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Hashemi J, Lipson DA, Arndt KA, Davidson SJ, Kalhori A, Lunneberg K, van Delden L, Oechel WC, Zona D. Thermokarst landscape exhibits large nitrous oxide emissions in Alaska's coastal polygonal tundra. COMMUNICATIONS EARTH & ENVIRONMENT 2024; 5:473. [PMID: 39220210 PMCID: PMC11364506 DOI: 10.1038/s43247-024-01583-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Accepted: 07/26/2024] [Indexed: 09/04/2024]
Abstract
Global atmospheric concentrations of nitrous oxide have been increasing over previous decades with emerging research suggesting the Arctic as a notable contributor. Thermokarst processes, increasing temperature, and changes in drainage can cause degradation of polygonal tundra landscape features resulting in elevated, well-drained, unvegetated soil surfaces that exhibit large nitrous oxide emissions. Here, we outline the magnitude and some of the dominant factors controlling variability in emissions for these thermokarst landscape features in the North Slope of Alaska. We measured strong nitrous oxide emissions during the growing season from unvegetated high centered polygons (median (mean) = 104.7 (187.7) µg N2O-N m-2 h-1), substantially higher than mean rates associated with Arctic tundra wetlands and of similar magnitude to unvegetated hotspots in peat plateaus and palsa mires. In the absence of vegetation, isotopic enrichment of 15N in these thermokarst features indicates a greater influence of microbial processes, (denitrification and nitrification) from barren soil. Findings reveal that the thermokarst features discussed here (~1.5% of the study area) are likely a notable source of nitrous oxide emissions, as inferred from chamber-based estimates. Growing season emissions, estimated at 16 (28) mg N2O-N ha-1 h-1, may be large enough to affect landscape-level greenhouse gas budgets.
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Affiliation(s)
- Josh Hashemi
- Biology Department, San Diego State University, San Diego, CA USA
- Department of Land, Air and Water Resources, University of California Davis, Davis, CA USA
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany
| | - David A. Lipson
- Biology Department, San Diego State University, San Diego, CA USA
| | | | - Scott J. Davidson
- University of Plymouth School of Geography, Earth and Environmental Sciences, Plymouth, UK
| | - Aram Kalhori
- GFZ German Research Centre for Geosciences, Potsdam, Germany
| | - Kyle Lunneberg
- Biology Department, San Diego State University, San Diego, CA USA
| | - Lona van Delden
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany
| | - Walter C. Oechel
- Biology Department, San Diego State University, San Diego, CA USA
- Department of Geography, University of Exeter, Exeter, UK
| | - Donatella Zona
- Biology Department, San Diego State University, San Diego, CA USA
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
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Guo J, Feng H, Peng C, Du J, Wang W, Kneeshaw D, Pan C, Roberge G, Feng L, Chen A. Fire effects on soil CH 4 and N 2O fluxes across terrestrial ecosystems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 948:174708. [PMID: 39032756 DOI: 10.1016/j.scitotenv.2024.174708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 07/08/2024] [Accepted: 07/09/2024] [Indexed: 07/23/2024]
Abstract
Fire, as a natural disturbance, significantly shapes and influences the functions and services of terrestrial ecosystems via biotic and abiotic processes. Comprehending the influence of fire on soil greenhouse gas dynamics is crucial for understanding the feedback mechanisms between fire disturbances and climate change. Despite work on CO2 fluxes, there is a large uncertainty as to whether and how soil CH4 and N2O fluxes change in response to fire disturbance in terrestrial ecosystems. To narrow this knowledge gap, we performed a meta-analysis synthesizing 3615 paired observations from 116 global studies. Our findings revealed that fire increased global soil CH4 uptake in uplands by 23.2 %, soil CH4 emissions from peatlands by 74.7 %, and soil N2O emissions in terrestrial ecosystems (including upland and peatland) by 18.8 %. Fire increased soil CH4 uptake in boreal, temperate, and subtropical forests by 20.1 %, 38.8 %, and 30.2 %, respectively, and soil CH4 emissions in tropical forests by 193.3 %. Additionally, fire negatively affected soil total carbon (TC; -10.3 %), soil organic carbon (SOC; -15.6 %), microbial biomass carbon (MBC; -44.8 %), dissolved organic carbon (DOC; -27 %), microbial biomass nitrogen (MBN; -24.7 %), soil water content (SWC; -9.2 %), and water table depth (WTD; -68.2 %). Conversely, the fire increased soil bulk density (BD; +10.8 %), ammonium nitrogen (NH4+-N; +46 %), nitrate nitrogen (NO3--N; +54 %), pH (+4.4 %), and soil temperature (+15.4 %). Our meta-regression analysis showed that the positive effects of fire on soil CH4 and N2O emissions were significantly positively correlated with mean annual temperature (MAT) and mean annual precipitation (MAP), indicating that climate warming will amplify the positive effects of fire disturbance on soil CH4 and N2O emissions. Taken together, since higher future temperatures are likely to prolong the fire season and increase the potential of fires, this could lead to positive feedback between warming, fire events, CH4 and N2O emissions, and future climate change.
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Affiliation(s)
- Jiahuan Guo
- Key Laboratory of Ministry of Education for Genetics and Germplasm Innovation of Tropical Special Trees and Ornamental Plants, School of Tropical Agriculture and Forestry (School of Agricultural and Rural Affairs, School of Rural Revitalization), Hainan University, Haikou, Hainan 570228, China
| | - Huili Feng
- Key Laboratory of Ministry of Education for Genetics and Germplasm Innovation of Tropical Special Trees and Ornamental Plants, School of Tropical Agriculture and Forestry (School of Agricultural and Rural Affairs, School of Rural Revitalization), Hainan University, Haikou, Hainan 570228, China.
| | - Changhui Peng
- Department of Biological Sciences, University of Quebec at Montreal, Montreal, Quebec H3C 3P8, Canada; College of Geographic Science, Hunan Normal University, Changsha, Hunan 410081, China
| | - Juan Du
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Science, Wuhan, Hubei 430223, China
| | - Weifeng Wang
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Ecology and Environment, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
| | - Daniel Kneeshaw
- Department of Biological Sciences, University of Quebec at Montreal, Montreal, Quebec H3C 3P8, Canada
| | - Chang Pan
- College of Life Sciences, Anqing Normal University, Anqing, Anhui 246011, China
| | - Gabrielle Roberge
- Department of Biological Sciences, University of Quebec at Montreal, Montreal, Quebec H3C 3P8, Canada
| | - Lei Feng
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Anping Chen
- Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO 80523, USA
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3
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Walter Anthony KM, Anthony P, Hasson N, Edgar C, Sivan O, Eliani-Russak E, Bergman O, Minsley BJ, James SR, Pastick NJ, Kholodov A, Zimov S, Euskirchen E, Bret-Harte MS, Grosse G, Langer M, Nitzbon J. Upland Yedoma taliks are an unpredicted source of atmospheric methane. Nat Commun 2024; 15:6056. [PMID: 39025864 PMCID: PMC11258132 DOI: 10.1038/s41467-024-50346-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Accepted: 07/02/2024] [Indexed: 07/20/2024] Open
Abstract
Landscape drying associated with permafrost thaw is expected to enhance microbial methane oxidation in arctic soils. Here we show that ice-rich, Yedoma permafrost deposits, comprising a disproportionately large fraction of pan-arctic soil carbon, present an alternate trajectory. Field and laboratory observations indicate that talik (perennially thawed soils in permafrost) development in unsaturated Yedoma uplands leads to unexpectedly large methane emissions (35-78 mg m-2 d-1 summer, 150-180 mg m-2 d-1 winter). Upland Yedoma talik emissions were nearly three times higher annually than northern-wetland emissions on an areal basis. Approximately 70% emissions occurred in winter, when surface-soil freezing abated methanotrophy, enhancing methane escape from the talik. Remote sensing and numerical modeling indicate the potential for widespread upland talik formation across the pan-arctic Yedoma domain during the 21st and 22nd centuries. Contrary to current climate model predictions, these findings imply a positive and much larger permafrost-methane-climate feedback for upland Yedoma.
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Affiliation(s)
- K M Walter Anthony
- Water and Environmental Research Center, University Alaska Fairbanks, Fairbanks, AK, USA.
| | - P Anthony
- Water and Environmental Research Center, University Alaska Fairbanks, Fairbanks, AK, USA
| | - N Hasson
- Water and Environmental Research Center, University Alaska Fairbanks, Fairbanks, AK, USA
| | - C Edgar
- Institute of Arctic Biology, University Alaska Fairbanks, Fairbanks, AK, USA
| | - O Sivan
- Department of Earth and Environmental Sciences, Ben Gurion University of the Negev, Beersheva, Israel
| | - E Eliani-Russak
- Department of Earth and Environmental Sciences, Ben Gurion University of the Negev, Beersheva, Israel
| | - O Bergman
- Water and Environmental Research Center, University Alaska Fairbanks, Fairbanks, AK, USA
- Department of Earth and Environmental Sciences, Ben Gurion University of the Negev, Beersheva, Israel
| | - B J Minsley
- U.S. Geological Survey, Geology, Geophysics, and Geochemistry Science Center, Denver, CO, USA
| | - S R James
- U.S. Geological Survey, Geology, Geophysics, and Geochemistry Science Center, Denver, CO, USA
| | - N J Pastick
- U.S. Geological Survey, Earth Resources Observation and Science Center, Sioux Falls, SD, USA
| | - A Kholodov
- Geophysical Research Institute, University Alaska Fairbanks, Fairbanks, AK, USA
| | - S Zimov
- Pacific Geographical Institute of the Russian Academy of Sciences, Northeast Science Station, Cherskiy, Russia
| | - E Euskirchen
- Institute of Arctic Biology, University Alaska Fairbanks, Fairbanks, AK, USA
| | - M S Bret-Harte
- Institute of Arctic Biology, University Alaska Fairbanks, Fairbanks, AK, USA
| | - G Grosse
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany
- University of Potsdam, Institute of Geosciences, Potsdam, Germany
| | - M Langer
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany
- Department of Earth Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - J Nitzbon
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany
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Graham EB, Garayburu-Caruso VA, Wu R, Zheng J, McClure R, Jones GD. Genomic fingerprints of the world's soil ecosystems. mSystems 2024; 9:e0111223. [PMID: 38722174 PMCID: PMC11237643 DOI: 10.1128/msystems.01112-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 03/25/2024] [Indexed: 06/19/2024] Open
Abstract
Despite the explosion of soil metagenomic data, we lack a synthesized understanding of patterns in the distribution and functions of soil microorganisms. These patterns are critical to predictions of soil microbiome responses to climate change and resulting feedbacks that regulate greenhouse gas release from soils. To address this gap, we assay 1,512 manually curated soil metagenomes using complementary annotation databases, read-based taxonomy, and machine learning to extract multidimensional genomic fingerprints of global soil microbiomes. Our objective is to uncover novel biogeographical patterns of soil microbiomes across environmental factors and ecological biomes with high molecular resolution. We reveal shifts in the potential for (i) microbial nutrient acquisition across pH gradients; (ii) stress-, transport-, and redox-based processes across changes in soil bulk density; and (iii) greenhouse gas emissions across biomes. We also use an unsupervised approach to reveal a collection of soils with distinct genomic signatures, characterized by coordinated changes in soil organic carbon, nitrogen, and cation exchange capacity and in bulk density and clay content that may ultimately reflect soil environments with high microbial activity. Genomic fingerprints for these soils highlight the importance of resource scavenging, plant-microbe interactions, fungi, and heterotrophic metabolisms. Across all analyses, we observed phylogenetic coherence in soil microbiomes-more closely related microorganisms tended to move congruently in response to soil factors. Collectively, the genomic fingerprints uncovered here present a basis for global patterns in the microbial mechanisms underlying soil biogeochemistry and help beget tractable microbial reaction networks for incorporation into process-based models of soil carbon and nutrient cycling.IMPORTANCEWe address a critical gap in our understanding of soil microorganisms and their functions, which have a profound impact on our environment. We analyzed 1,512 global soils with advanced analytics to create detailed genetic profiles (fingerprints) of soil microbiomes. Our work reveals novel patterns in how microorganisms are distributed across different soil environments. For instance, we discovered shifts in microbial potential to acquire nutrients in relation to soil acidity, as well as changes in stress responses and potential greenhouse gas emissions linked to soil structure. We also identified soils with putative high activity that had unique genomic characteristics surrounding resource acquisition, plant-microbe interactions, and fungal activity. Finally, we observed that closely related microorganisms tend to respond in similar ways to changes in their surroundings. Our work is a significant step toward comprehending the intricate world of soil microorganisms and its role in the global climate.
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Affiliation(s)
- Emily B. Graham
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington, USA
- School of Biological Sciences, Washington State University, Pullman, Washington, USA
| | | | - Ruonan Wu
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Jianqiu Zheng
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Ryan McClure
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Gerrad D. Jones
- Department of Biological and Ecological Engineering, Oregon State University, Corvallis, Oregon, USA
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5
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Liu Z, Chen B, Wang S, Xu X, Chen H, Liu X, He JS, Wang J, Wang J, Chen J, Wang X, Zheng C, Zhu K, Wang X. More enhanced non-growing season methane exchanges under warming on the Qinghai-Tibetan Plateau. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 917:170438. [PMID: 38286283 DOI: 10.1016/j.scitotenv.2024.170438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 01/12/2024] [Accepted: 01/23/2024] [Indexed: 01/31/2024]
Abstract
Uncertainty in methane (CH4) exchanges across wetlands and grasslands in the Qinghai-Tibetan Plateau (QTP) is projected to increase due to continuous permafrost degradation and asymmetrical seasonal warming. Temperature plays a vital role in regulating CH4 exchange, yet the seasonal patterns of temperature dependencies for CH4 fluxes over the wetlands and grasslands on the QTP remain poorly understood. Here, we demonstrated a stronger warming response of CH4 exchanges during the non-growing season compared to the growing season on the QTP. Analyzing 9745 daily observations and employing four methods -regression fitting of temperature-CH4 flux, temperature dependence calculations, field-based and model-based control experiments-we found that warming intensified CH4 emissions in wetlands and uptakes in grasslands. Specifically, the average reaction intensity in the non-growing season surpasses that in the growing season by 1.89 and 4.80 times, respectively. This stronger warming response of CH4 exchanges during the non-growing season significantly increases the regional CH4 exchange on the QTP. Our research reveals that CH4 exchanges in the QTP have a higher warming sensitivity in non-growing seasons, which meanwhile are dominated by a larger warming rate than the annual average. The combined effects of these two factors will significantly alter the CH4 source/sink on the QTP. Neglecting these impacts would lead to inaccurate estimations of CH4 source/sink over the QTP under climate warming.
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Affiliation(s)
- Zhenhai Liu
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China; Key Laboratory of Coupling Process and Effect of Natural Resources Elements, Beijing, 100055, China
| | - Bin Chen
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; Key Laboratory of Coupling Process and Effect of Natural Resources Elements, Beijing, 100055, China.
| | - Shaoqiang Wang
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China; Hubei Key Laboratory of Regional Ecology and Environmental Change, School of Geography and Information Engineering, China University of Geosciences, Wuhan 430078, China; Technology Innovation Center for Intelligent Monitoring and Spatial Regulation of Land Carbon Sequestrations, Ministry of Natural Resources, Wuhan 430078, China.
| | - Xiyan Xu
- Key Laboratory of Regional Climate-Environment for Temperate East Asia, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Huai Chen
- Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; Zoige Peatland and Global Change Research Station, Chinese Academy of Sciences, Hongyuan 624400, China
| | - Xinwei Liu
- Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; Zoige Peatland and Global Change Research Station, Chinese Academy of Sciences, Hongyuan 624400, China
| | - Jin-Sheng He
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730000, China; Department of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing 100871, China
| | - Jianbin Wang
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730000, China
| | - Jinsong Wang
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Jinghua Chen
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiaobo Wang
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Chen Zheng
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kai Zhu
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xueqing Wang
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
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6
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Feron S, Malhotra A, Bansal S, Fluet-Chouinard E, McNicol G, Knox SH, Delwiche KB, Cordero RR, Ouyang Z, Zhang Z, Poulter B, Jackson RB. Recent increases in annual, seasonal, and extreme methane fluxes driven by changes in climate and vegetation in boreal and temperate wetland ecosystems. GLOBAL CHANGE BIOLOGY 2024; 30:e17131. [PMID: 38273508 DOI: 10.1111/gcb.17131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 11/15/2023] [Accepted: 12/15/2023] [Indexed: 01/27/2024]
Abstract
Climate warming is expected to increase global methane (CH4 ) emissions from wetland ecosystems. Although in situ eddy covariance (EC) measurements at ecosystem scales can potentially detect CH4 flux changes, most EC systems have only a few years of data collected, so temporal trends in CH4 remain uncertain. Here, we use established drivers to hindcast changes in CH4 fluxes (FCH4 ) since the early 1980s. We trained a machine learning (ML) model on CH4 flux measurements from 22 [methane-producing sites] in wetland, upland, and lake sites of the FLUXNET-CH4 database with at least two full years of measurements across temperate and boreal biomes. The gradient boosting decision tree ML model then hindcasted daily FCH4 over 1981-2018 using meteorological reanalysis data. We found that, mainly driven by rising temperature, half of the sites (n = 11) showed significant increases in annual, seasonal, and extreme FCH4 , with increases in FCH4 of ca. 10% or higher found in the fall from 1981-1989 to 2010-2018. The annual trends were driven by increases during summer and fall, particularly at high-CH4 -emitting fen sites dominated by aerenchymatous plants. We also found that the distribution of days of extremely high FCH4 (defined according to the 95th percentile of the daily FCH4 values over a reference period) have become more frequent during the last four decades and currently account for 10-40% of the total seasonal fluxes. The share of extreme FCH4 days in the total seasonal fluxes was greatest in winter for boreal/taiga sites and in spring for temperate sites, which highlights the increasing importance of the non-growing seasons in annual budgets. Our results shed light on the effects of climate warming on wetlands, which appears to be extending the CH4 emission seasons and boosting extreme emissions.
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Affiliation(s)
- Sarah Feron
- Knowledge Infrastructures, Campus Fryslân, University of Groningen, Groningen, The Netherlands
- Department of Earth System Science, Stanford University, Stanford, California, USA
- Department of Physics, Universidad de Santiago, Santiago, Chile
| | - Avni Malhotra
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Sheel Bansal
- U.S. Geological Survey, Northern Prairie Wildlife Research Center, Jamestown, North Dakota, USA
| | - Etienne Fluet-Chouinard
- Earth Systems Science Division, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Gavin McNicol
- Department of Earth System Science, Stanford University, Stanford, California, USA
- Department of Earth and Environmental Sciences, University of Illinois Chicago, Chicago, Illinois, USA
| | - Sara H Knox
- Department of Geography, The University of British Columbia, Vancouver, British Columbia, Canada
- Department of Geography, McGill University, Montreal, Quebec, Canada
| | - Kyle B Delwiche
- Department of Earth System Science, Stanford University, Stanford, California, USA
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, California, USA
| | - Raul R Cordero
- Department of Physics, Universidad de Santiago, Santiago, Chile
| | - Zutao Ouyang
- Department of Earth System Science, Stanford University, Stanford, California, USA
| | - Zhen Zhang
- Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
| | - Benjamin Poulter
- Biospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
| | - Robert B Jackson
- Department of Earth System Science, Stanford University, Stanford, California, USA
- Woods Institute for the Environment, Stanford University, Stanford, California, USA
- Precourt Institute for Energy, Stanford, California, USA
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7
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Wang X, Song C, Chen N, Qiao T, Wang S, Jiang J, Du Y. Gas storage of peat in autumn and early winter in permafrost peatland. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 898:165548. [PMID: 37454856 DOI: 10.1016/j.scitotenv.2023.165548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 07/13/2023] [Accepted: 07/13/2023] [Indexed: 07/18/2023]
Abstract
The carbon (C) balance of permafrost peatlands in autumn and winter, which affects the annual C budget estimation, has become a hotspot of studies on peatlands C cycle. This study combined the static chamber method, in situ soil profile measurements, and incubation experiments to investigate release and storage of C during autumn and early winter in a permafrost peatland in the Da Xing'an Mountains, Northeast China. Our results showed that the peak values of CH4 fluxes (30 August 2016) lagged behind those of CO2 fluxes (24 July 2016). At the onset of soil freezing, CH4 fluxes slightly increased, while CO2 fluxes decreased. During soil freezing in autumn, gases were found to be mainly stored in the soil as dissolved CH4 and CO2 and dissolved C concentrations (CH4, CO2, and DOC (dissolved organic carbon)) increased with depth. DOC concentrations were closely related to dissolved C gases, implying that the stored dissolved C gases might be derived from DOC decomposition. The CO2: CH4 ratio decreased sharply from the freezing of the surface layer to the total freezing of the soil, indicating larger CH4 storage in totally frozen soil. The incubation experiments also showed larger CH4 storage in the frozen soils and the stored C gases could influence the assessment of C emissions during thawing. These findings have important implications for clarifying the gas storage of permafrost peatland in autumn and early winter. The results may also clarify the key link of C emissions between the growing season and the nongrowing season.
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Affiliation(s)
- Xianwei Wang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
| | - Changchun Song
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China; Dalian University of Technology, Dalian 116024, China.
| | - Ning Chen
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
| | - Tianhua Qiao
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
| | - Shujie Wang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China; University of Chinese Academy Sciences, Beijing 100049, China
| | - Jingyi Jiang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
| | - Yu Du
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
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Watts JD, Farina M, Kimball JS, Schiferl LD, Liu Z, Arndt KA, Zona D, Ballantyne A, Euskirchen ES, Parmentier FJW, Helbig M, Sonnentag O, Tagesson T, Rinne J, Ikawa H, Ueyama M, Kobayashi H, Sachs T, Nadeau DF, Kochendorfer J, Jackowicz-Korczynski M, Virkkala A, Aurela M, Commane R, Byrne B, Birch L, Johnson MS, Madani N, Rogers B, Du J, Endsley A, Savage K, Poulter B, Zhang Z, Bruhwiler LM, Miller CE, Goetz S, Oechel WC. Carbon uptake in Eurasian boreal forests dominates the high-latitude net ecosystem carbon budget. GLOBAL CHANGE BIOLOGY 2023; 29:1870-1889. [PMID: 36647630 DOI: 10.1111/gcb.16553] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 05/28/2023]
Abstract
Arctic-boreal landscapes are experiencing profound warming, along with changes in ecosystem moisture status and disturbance from fire. This region is of global importance in terms of carbon feedbacks to climate, yet the sign (sink or source) and magnitude of the Arctic-boreal carbon budget within recent years remains highly uncertain. Here, we provide new estimates of recent (2003-2015) vegetation gross primary productivity (GPP), ecosystem respiration (Reco ), net ecosystem CO2 exchange (NEE; Reco - GPP), and terrestrial methane (CH4 ) emissions for the Arctic-boreal zone using a satellite data-driven process-model for northern ecosystems (TCFM-Arctic), calibrated and evaluated using measurements from >60 tower eddy covariance (EC) sites. We used TCFM-Arctic to obtain daily 1-km2 flux estimates and annual carbon budgets for the pan-Arctic-boreal region. Across the domain, the model indicated an overall average NEE sink of -850 Tg CO2 -C year-1 . Eurasian boreal zones, especially those in Siberia, contributed to a majority of the net sink. In contrast, the tundra biome was relatively carbon neutral (ranging from small sink to source). Regional CH4 emissions from tundra and boreal wetlands (not accounting for aquatic CH4 ) were estimated at 35 Tg CH4 -C year-1 . Accounting for additional emissions from open water aquatic bodies and from fire, using available estimates from the literature, reduced the total regional NEE sink by 21% and shifted many far northern tundra landscapes, and some boreal forests, to a net carbon source. This assessment, based on in situ observations and models, improves our understanding of the high-latitude carbon status and also indicates a continued need for integrated site-to-regional assessments to monitor the vulnerability of these ecosystems to climate change.
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Affiliation(s)
| | - Mary Farina
- Woodwell Climate Research Center, Falmouth, Massachusetts, USA
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, Montana, USA
| | - John S Kimball
- Numerical Terradynamic Simulation Group (NTSG), ISB 415, University of Montana, Missoula, Montana, USA
| | - Luke D Schiferl
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA
| | - Zhihua Liu
- Numerical Terradynamic Simulation Group (NTSG), ISB 415, University of Montana, Missoula, Montana, USA
| | - Kyle A Arndt
- Woodwell Climate Research Center, Falmouth, Massachusetts, USA
- Earth Systems Research Center, University of New Hampshire, Durham, New Hampshire, USA
| | - Donatella Zona
- Global Change Research Group, Department of Biology, Physical Sciences 240, San Diego State University, San Diego, California, USA
| | - Ashley Ballantyne
- Global Climate and Ecology Laboratory, W.A. Franke College of Forestry and Conservation, University of Montana, Missoula, Montana, USA
| | | | - Frans-Jan W Parmentier
- Department of Geosciences, Center for Biogeochemistry in the Anthropocene, University of Oslo, Oslo, Norway
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Manuel Helbig
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada
| | | | - Torbern Tagesson
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Janne Rinne
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
- Natural Resources Institute Finland, Helsinki, Finland
| | - Hiroki Ikawa
- Hokkaido Agricultural Research Center, NARO, Sapporo, Japan
| | | | - Hideki Kobayashi
- JAMSTEC-Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan
| | - Torsten Sachs
- GFZ German Research Centre for Geoscience, Potsdam, Germany
| | - Daniel F Nadeau
- Department of Civil and Water Engineering, Université Laval, Quebec City, Quebec, Canada
| | - John Kochendorfer
- NOAA Air Resources Laboratory, Atmospheric and Turbulent Diffusion Division, Oak Ridge, Tennessee, USA
| | - Marcin Jackowicz-Korczynski
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
- Department of Ecoscience, Aarhus University, Roskilde, Denmark
| | - Anna Virkkala
- Woodwell Climate Research Center, Falmouth, Massachusetts, USA
| | - Mika Aurela
- Finnish Meteorological Institute, Helsinki, Finland
| | - Roisin Commane
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, USA
| | - Brendan Byrne
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Leah Birch
- Woodwell Climate Research Center, Falmouth, Massachusetts, USA
| | - Matthew S Johnson
- Biospheric Science Branch, NASA Ames Research Center, Moffett Field, California, USA
| | - Nima Madani
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Brendan Rogers
- Woodwell Climate Research Center, Falmouth, Massachusetts, USA
| | - Jinyang Du
- Numerical Terradynamic Simulation Group (NTSG), ISB 415, University of Montana, Missoula, Montana, USA
| | - Arthur Endsley
- Numerical Terradynamic Simulation Group (NTSG), ISB 415, University of Montana, Missoula, Montana, USA
| | - Kathleen Savage
- Woodwell Climate Research Center, Falmouth, Massachusetts, USA
| | - Ben Poulter
- NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
| | - Zhen Zhang
- Department of Geographical Sciences, University of Maryland, College Park, Maryland, USA
| | - Lori M Bruhwiler
- NOAA Earth System Research Laboratory, Global Monitoring Division, Boulder, Colorado, USA
| | - Charles E Miller
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Scott Goetz
- School of Informatics, Computing and Cyber Systems, Northern Arizona University, Flagstaff, Arizona, USA
| | - Walter C Oechel
- Global Change Research Group, Department of Biology, Physical Sciences 240, San Diego State University, San Diego, California, USA
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9
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Zona D, Lafleur PM, Hufkens K, Gioli B, Bailey B, Burba G, Euskirchen ES, Watts JD, Arndt KA, Farina M, Kimball JS, Heimann M, Göckede M, Pallandt M, Christensen TR, Mastepanov M, López‐Blanco E, Dolman AJ, Commane R, Miller CE, Hashemi J, Kutzbach L, Holl D, Boike J, Wille C, Sachs T, Kalhori A, Humphreys ER, Sonnentag O, Meyer G, Gosselin GH, Marsh P, Oechel WC. Pan-Arctic soil moisture control on tundra carbon sequestration and plant productivity. GLOBAL CHANGE BIOLOGY 2023; 29:1267-1281. [PMID: 36353841 PMCID: PMC10099953 DOI: 10.1111/gcb.16487] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 09/16/2022] [Accepted: 10/05/2022] [Indexed: 05/26/2023]
Abstract
Long-term atmospheric CO2 concentration records have suggested a reduction in the positive effect of warming on high-latitude carbon uptake since the 1990s. A variety of mechanisms have been proposed to explain the reduced net carbon sink of northern ecosystems with increased air temperature, including water stress on vegetation and increased respiration over recent decades. However, the lack of consistent long-term carbon flux and in situ soil moisture data has severely limited our ability to identify the mechanisms responsible for the recent reduced carbon sink strength. In this study, we used a record of nearly 100 site-years of eddy covariance data from 11 continuous permafrost tundra sites distributed across the circumpolar Arctic to test the temperature (expressed as growing degree days, GDD) responses of gross primary production (GPP), net ecosystem exchange (NEE), and ecosystem respiration (ER) at different periods of the summer (early, peak, and late summer) including dominant tundra vegetation classes (graminoids and mosses, and shrubs). We further tested GPP, NEE, and ER relationships with soil moisture and vapor pressure deficit to identify potential moisture limitations on plant productivity and net carbon exchange. Our results show a decrease in GPP with rising GDD during the peak summer (July) for both vegetation classes, and a significant relationship between the peak summer GPP and soil moisture after statistically controlling for GDD in a partial correlation analysis. These results suggest that tundra ecosystems might not benefit from increased temperature as much as suggested by several terrestrial biosphere models, if decreased soil moisture limits the peak summer plant productivity, reducing the ability of these ecosystems to sequester carbon during the summer.
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Affiliation(s)
- Donatella Zona
- Department BiologySan Diego State UniversitySan DiegoCaliforniaUSA
- School of BiosciencesUniversity of SheffieldSheffieldUK
| | - Peter M. Lafleur
- School of the EnvironmentTrent UniversityPeterboroughOntarioCanada
| | | | - Beniamino Gioli
- National Research Council (CNR)Institute of BioEconomy (IBE)FlorenceItaly
| | - Barbara Bailey
- Department of Mathematics and Statistics, San Diego State UniversitySan DiegoCaliforniaUSA
| | - George Burba
- LI‐COR BiosciencesLincolnNebraskaUSA
- The Robert B. Daugherty Water for Food Global Institute and School of Natural ResourcesUniversity of NebraskaLincolnNebraskaUSA
| | | | - Jennifer D. Watts
- Woodwell Climate Research CenterFalmouthMassachusettsUSA
- W.A. Franke College of Forestry & ConservationThe University of MontanaMissoulaMontanaUSA
| | - Kyle A. Arndt
- Woodwell Climate Research CenterFalmouthMassachusettsUSA
| | - Mary Farina
- Woodwell Climate Research CenterFalmouthMassachusettsUSA
| | - John S. Kimball
- W.A. Franke College of Forestry & ConservationThe University of MontanaMissoulaMontanaUSA
| | - Martin Heimann
- Max Planck Institute for BiogeochemistryJenaGermany
- Faculty of Science, Institute for Atmospheric and Earth System Research (INAR) / Physics, University of HelsinkiHelsinkiFinland
| | | | | | - Torben R. Christensen
- Department of Ecoscience, Arctic Research CentreAarhus UniversityRoskildeDenmark
- Oulanka Research StationOulu UniversityKuusamoFinland
| | - Mikhail Mastepanov
- Department of Ecoscience, Arctic Research CentreAarhus UniversityRoskildeDenmark
- Oulanka Research StationOulu UniversityKuusamoFinland
| | - Efrén López‐Blanco
- Department of Ecoscience, Arctic Research CentreAarhus UniversityRoskildeDenmark
- Department of Environment and Minerals, Greenland Institute of Natural ResourcesNuukGreenland
| | | | - Roisin Commane
- Department of Earth and Environmental Sciences, Lamont‐Doherty Earth ObservatoryColumbia UniversityPalisadesNew YorkUSA
| | - Charles E. Miller
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCaliforniaUSA
| | - Josh Hashemi
- Department BiologySan Diego State UniversitySan DiegoCaliforniaUSA
- Environmental Meteorology, Institute of Earth and Environmental SciencesUniversity of FreiburgFreiburgGermany
| | - Lars Kutzbach
- Institute of Soil Science, Center for Earth System Research and Sustainability (CEN)Universität HamburgHamburgGermany
| | - David Holl
- Institute of Soil Science, Center for Earth System Research and Sustainability (CEN)Universität HamburgHamburgGermany
| | - Julia Boike
- Geography DepartmentHumboldt‐Universität zu BerlinBerlinGermany
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine ResearchPotsdamGermany
| | | | - Torsten Sachs
- GFZ German Research Centre for GeosciencesPotsdamGermany
| | - Aram Kalhori
- GFZ German Research Centre for GeosciencesPotsdamGermany
| | - Elyn R. Humphreys
- Department of Geography & Environmental StudiesCarleton UniversityOttawaOntarioCanada
| | - Oliver Sonnentag
- Département de GéographieUniversité de MontréalMontréalQuebecCanada
| | - Gesa Meyer
- Département de GéographieUniversité de MontréalMontréalQuebecCanada
| | | | - Philip Marsh
- Department of Geography and Environmental Studies, Wilfrid Laurier UniversityWaterlooOntarioCanada
| | - Walter C. Oechel
- Department BiologySan Diego State UniversitySan DiegoCaliforniaUSA
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10
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Bansal S, Post van der Burg M, Fern RR, Jones JW, Lo R, McKenna OP, Tangen BA, Zhang Z, Gleason RA. Large increases in methane emissions expected from North America's largest wetland complex. SCIENCE ADVANCES 2023; 9:eade1112. [PMID: 36857447 PMCID: PMC9977182 DOI: 10.1126/sciadv.ade1112] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 01/30/2023] [Indexed: 06/18/2023]
Abstract
Natural methane (CH4) emissions from aquatic ecosystems may rise because of human-induced climate warming, although the magnitude of increase is highly uncertain. Using an exceptionally large CH4 flux dataset (~19,000 chamber measurements) and remotely sensed information, we modeled plot- and landscape-scale wetland CH4 emissions from the Prairie Pothole Region (PPR), North America's largest wetland complex. Plot-scale CH4 emissions were driven by hydrology, temperature, vegetation, and wetland size. Historically, landscape-scale PPR wetland CH4 emissions were largely dependent on total wetland extent. However, regardless of future wetland extent, PPR CH4 emissions are predicted to increase by two- or threefold by 2100 under moderate or severe warming scenarios, respectively. Our findings suggest that international efforts to decrease atmospheric CH4 concentrations should jointly account for anthropogenic and natural emissions to maintain climate mitigation targets to the end of the century.
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Affiliation(s)
- Sheel Bansal
- U.S. Geological Survey, Northern Prairie Wildlife Research Center, Jamestown, ND, USA
| | - Max Post van der Burg
- U.S. Geological Survey, Northern Prairie Wildlife Research Center, Jamestown, ND, USA
| | - Rachel R. Fern
- U.S. Geological Survey, Northern Prairie Wildlife Research Center, Jamestown, ND, USA
- Texas Parks and Wildlife Department, San Marcos, TX, USA
| | - John W. Jones
- U.S. Geological Survey, Hydrologic Remote Sensing Branch, Kearneysville, WV, USA
| | - Rachel Lo
- U.S. Geological Survey, Northern Prairie Wildlife Research Center, Jamestown, ND, USA
| | - Owen P. McKenna
- U.S. Geological Survey, Northern Prairie Wildlife Research Center, Jamestown, ND, USA
| | - Brian A. Tangen
- U.S. Geological Survey, Northern Prairie Wildlife Research Center, Jamestown, ND, USA
| | - Zhen Zhang
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, USA
| | - Robert A. Gleason
- U.S. Geological Survey, Northern Prairie Wildlife Research Center, Jamestown, ND, USA
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11
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Wang H, Yu L, Chen L, Zhang Z, Li X, Liang N, Peng C, He JS. Carbon fluxes and soil carbon dynamics along a gradient of biogeomorphic succession in alpine wetlands of Tibetan Plateau. FUNDAMENTAL RESEARCH 2023; 3:151-159. [PMID: 38932928 PMCID: PMC11197537 DOI: 10.1016/j.fmre.2022.09.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 09/16/2022] [Accepted: 09/19/2022] [Indexed: 11/07/2022] Open
Abstract
Hydrological changes under climate warming drive the biogeomorphic succession of wetlands and may trigger substantial carbon loss from the carbon-rich ecosystems. Although many studies have explored the responses of wetland carbon emissions to short-term hydrological change, it remains poorly understood how the carbon cycle evolves with hydrology-driven wetland succession. Here, we used a space-for-time approach across hydrological gradients on the Tibetan Plateau to examine the dynamics of ecosystem carbon fluxes (carbon dioxide (CO2) and methane (CH4)) and soil organic carbon pools during alpine wetland succession. We found that the succession from mesic meadow to fen changed the seasonality of both CO2 and CH4 fluxes, which was related to the shift in plant community composition, enhanced regulation of soil hydrology and increasing contribution of spring-thaw emission. The paludification caused a switch from net uptake of gaseous carbon to net release on an annual timescale but produced a large accumulation of soil organic carbon. We attempted to attribute the paradox between evidence from the carbon fluxes and pools to the lateral carbon input and the systematic changes of historical climate, given that the wetlands are spatially low-lying with strong temporal climate-carbon cycle interactions. These findings demonstrate a systematic change in the carbon cycle with succession and suggest that biogeomorphic succession and lateral carbon flows are both important for understanding the long-term dynamics of wetland carbon footprints.
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Affiliation(s)
- Hao Wang
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 730000, China
- Institute of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing 100871, China
| | - Lingfei Yu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Litong Chen
- Qinghai Haibei National Field Research Station of Alpine Grassland Ecosystem, and Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China
| | - Zhenhua Zhang
- Qinghai Haibei National Field Research Station of Alpine Grassland Ecosystem, and Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China
| | - Xuefei Li
- Institute for Atmospheric and Earth System Research (INAR)/Physics, Faculty of Science, University of Helsinki, P.O. Box 68, Helsinki FI-00014, Finland
| | - Naishen Liang
- Earth System Division, National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506, Japan
| | - Changhui Peng
- Department of Biology Sciences, Institute of Environment Sciences, University of Quebec at Montreal, Montreal, QC H3C 3P8, Canada
| | - Jin-Sheng He
- Institute of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing 100871, China
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730000, China
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12
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Wetland emission and atmospheric sink changes explain methane growth in 2020. Nature 2022; 612:477-482. [PMID: 36517714 DOI: 10.1038/s41586-022-05447-w] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 10/14/2022] [Indexed: 12/15/2022]
Abstract
Atmospheric methane growth reached an exceptionally high rate of 15.1 ± 0.4 parts per billion per year in 2020 despite a probable decrease in anthropogenic methane emissions during COVID-19 lockdowns1. Here we quantify changes in methane sources and in its atmospheric sink in 2020 compared with 2019. We find that, globally, total anthropogenic emissions decreased by 1.2 ± 0.1 teragrams of methane per year (Tg CH4 yr-1), fire emissions decreased by 6.5 ± 0.1 Tg CH4 yr-1 and wetland emissions increased by 6.0 ± 2.3 Tg CH4 yr-1. Tropospheric OH concentration decreased by 1.6 ± 0.2 per cent relative to 2019, mainly as a result of lower anthropogenic nitrogen oxide (NOx) emissions and associated lower free tropospheric ozone during pandemic lockdowns2. From atmospheric inversions, we also infer that global net emissions increased by 6.9 ± 2.1 Tg CH4 yr-1 in 2020 relative to 2019, and global methane removal from reaction with OH decreased by 7.5 ± 0.8 Tg CH4 yr-1. Therefore, we attribute the methane growth rate anomaly in 2020 relative to 2019 to lower OH sink (53 ± 10 per cent) and higher natural emissions (47 ± 16 per cent), mostly from wetlands. In line with previous findings3,4, our results imply that wetland methane emissions are sensitive to a warmer and wetter climate and could act as a positive feedback mechanism in the future. Our study also suggests that nitrogen oxide emission trends need to be taken into account when implementing the global anthropogenic methane emissions reduction pledge5.
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13
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Poppeliers SWM, Hefting M, Dorrepaal E, Weedon JT. Functional microbial ecology in arctic soils: the need for a year-round perspective. FEMS Microbiol Ecol 2022; 98:6824434. [PMID: 36368693 PMCID: PMC9701097 DOI: 10.1093/femsec/fiac134] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 11/01/2022] [Accepted: 11/09/2022] [Indexed: 11/13/2022] Open
Abstract
The microbial ecology of arctic and sub-arctic soils is an important aspect of the global carbon cycle, due to the sensitivity of the large soil carbon stocks to ongoing climate warming. These regions are characterized by strong climatic seasonality, but the emphasis of most studies on the short vegetation growing season could potentially limit our ability to predict year-round ecosystem functions. We compiled a database of studies from arctic, subarctic, and boreal environments that include sampling of microbial community and functions outside the growing season. We found that for studies comparing across seasons, in most environments, microbial biomass and community composition vary intra-annually, with the spring thaw period often identified by researchers as the most dynamic time of year. This seasonality of microbial communities will have consequences for predictions of ecosystem function under climate change if it results in: seasonality in process kinetics of microbe-mediated functions; intra-annual variation in the importance of different (a)biotic drivers; and/or potential temporal asynchrony between climate change-related perturbations and their corresponding effects. Future research should focus on (i) sampling throughout the entire year; (ii) linking these multi-season measures of microbial community composition with corresponding functional or physiological measurements to elucidate the temporal dynamics of the links between them; and (iii) identifying dominant biotic and abiotic drivers of intra-annual variation in different ecological contexts.
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Affiliation(s)
- Sanne W M Poppeliers
- Corresponding author: Department of Biology, Utrecht University, 3584 CH, The Netherlands. E-mail:
| | - Mariet Hefting
- Department of Biology, Utrecht University, 3584 CH, The Netherlands
| | - Ellen Dorrepaal
- Climate Impacts Research Centre, Umea University, SE-981 07, Abisko, Sweden
| | - James T Weedon
- Department of Ecological Science, Vrije Universiteit Amsterdam, 1081 HV, Amsterdam, The Netherlands
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14
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Kuai L, Parazoo NC, Shi M, Miller CE, Baker I, Bloom AA, Bowman K, Lee M, Zeng Z, Commane R, Montzka SA, Berry J, Sweeney C, Miller JB, Yung YL. Quantifying Northern High Latitude Gross Primary Productivity (GPP) Using Carbonyl Sulfide (OCS). GLOBAL BIOGEOCHEMICAL CYCLES 2022; 36:e2021GB007216. [PMID: 36590828 PMCID: PMC9787914 DOI: 10.1029/2021gb007216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 07/21/2022] [Accepted: 08/08/2022] [Indexed: 06/17/2023]
Abstract
The northern high latitude (NHL, 40°N to 90°N) is where the second peak region of gross primary productivity (GPP) other than the tropics. The summer NHL GPP is about 80% of the tropical peak, but both regions are still highly uncertain (Norton et al. 2019, https://doi.org/10.5194/bg-16-3069-2019). Carbonyl sulfide (OCS) provides an important proxy for photosynthetic carbon uptake. Here we optimize the OCS plant uptake fluxes across the NHL by fitting atmospheric concentration simulation with the GEOS-CHEM global transport model to the aircraft profiles acquired over Alaska during NASA's Carbon in Arctic Reservoirs Vulnerability Experiment (2012-2015). We use the empirical biome-specific linear relationship between OCS plant uptake flux and GPP to derive the six plant uptake OCS fluxes from different GPP data. Such GPP-based fluxes are used to drive the concentration simulations. We evaluate the simulations against the independent observations at two ground sites of Alaska. The optimized OCS fluxes suggest the NHL plant uptake OCS flux of -247 Gg S year-1, about 25% stronger than the ensemble mean of the six GPP-based OCS fluxes. GPP-based OCS fluxes systematically underestimate the peak growing season across the NHL, while a subset of models predict early start of season in Alaska, consistent with previous studies of net ecosystem exchange. The OCS optimized GPP of 34 PgC yr-1 for NHL is also about 25% more than the ensembles mean from six GPP data. Further work is needed to fully understand the environmental and biotic drivers and quantify their rate of photosynthetic carbon uptake in Arctic ecosystems.
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Affiliation(s)
- Le Kuai
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | | | - Mingjie Shi
- Pacific Northwest National LaboratoryRichlandWAUSA
| | - Charles E. Miller
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - Ian Baker
- Colorado State UniversityFort CollinsCOUSA
| | - Anthony A. Bloom
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - Kevin Bowman
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - Meemong Lee
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - Zhao‐Cheng Zeng
- University of California Los AngelesJIFRESSELos AngelesCAUSA
| | - Roisin Commane
- Lamont‐Doherty Earth Observatory at Columbia UniversityPalisadesNYUSA
| | | | | | | | | | - Yuk L. Yung
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
- California Institute of TechnologyPasadenaCAUSA
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15
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Fluid Migration through Permafrost and the Pool of Greenhouse Gases in Frozen Soils of an Oil and Gas Field. REMOTE SENSING 2022. [DOI: 10.3390/rs14153662] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Most methane (CH4) and carbon dioxide (CO2) emissions originate from the biodegradation of organic matter of soils and of degrading permafrost in the Arctic. However, there is limited evidence of the activity of geological sources, and little understanding of the pathways of migration of gaseous fluids through the porous mineral matrix filled with ice. We estimated the effect of geological factors on the winter storage of the greenhouse gases in frozen soils by statistical analysis of the geodatabase, which combined a field gas survey of frozen soils, subsurface sounding, and remote sensing data. Frozen soils stored on average 0.016 g CH4 m−3 and 11.5 g CO2 m−3. Microseeps, recognized by isolated anomalies of helium, had 30% higher CH4 concentrations. Lineaments marking margins of tectonic blocks were estimated to have 300% higher CH4 concentrations. High concentrations of propane and ethane indicated the contribution of diffuse fluid flow from hydrocarbon-bearing beds on 95% of the 130 km2 study area. In addition to the fluid contribution, we estimated an overwintering pool of greenhouse gases in frozen soil for the first time. Being at least 0.01–0.1% of the soil organic matter mass, these gaseous forms of carbon can be critical for the early-summer Arctic ecosystem functioning.
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16
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Domine F, Fourteau K, Picard G, Lackner G, Sarrazin D, Poirier M. Permafrost cooled in winter by thermal bridging through snow-covered shrub branches. NATURE GEOSCIENCE 2022; 15:554-560. [PMID: 35845978 PMCID: PMC9279148 DOI: 10.1038/s41561-022-00979-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
Considerable expansion of shrubs across the Arctic tundra has been observed in recent decades. These shrubs are thought to have a warming effect on permafrost by increasing snowpack thermal insulation, thereby limiting winter cooling and accelerating thaw. Here, we use ground temperature observations and heat transfer simulations to show that low shrubs can actually cool the ground in winter by providing a thermal bridge through the snowpack. Observations from unmanipulated herb tundra and shrub tundra sites on Bylot Island in the Canadian high Arctic reveal a 1.21 °C cooling effect between November and February. This is despite a snowpack that is twice as insulating in shrubs. The thermal bridging effect is reversed in spring when shrub branches absorb solar radiation and transfer heat to the ground. The overall thermal effect is likely to depend on snow and shrub characteristics and terrain aspect. The inclusion of these thermal bridging processes into climate models may have an important impact on projected greenhouse gas emissions by permafrost.
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Affiliation(s)
- Florent Domine
- Takuvik Joint International Laboratory, Université Laval (Canada) and CNRS-INSU (France), Québec, Canada
- Centre d’Études Nordiques, Université Laval, Québec, Canada
- Department of Chemistry, Université Laval, Québec, Canada
| | - Kévin Fourteau
- Université Grenoble Alpes, Université Toulouse, Météo-France, CNRS, CNRM, Centre d’Études de la Neige, Grenoble, France
| | - Ghislain Picard
- Université Grenoble Alpes, CNRS, IRD, Grenoble INP, IGE, Grenoble, France
| | - Georg Lackner
- Takuvik Joint International Laboratory, Université Laval (Canada) and CNRS-INSU (France), Québec, Canada
- Centre d’Études Nordiques, Université Laval, Québec, Canada
- Department of Civil and Water Engineering, Université Laval, Québec, Canada
| | - Denis Sarrazin
- Centre d’Études Nordiques, Université Laval, Québec, Canada
| | - Mathilde Poirier
- Centre d’Études Nordiques, Université Laval, Québec, Canada
- Department of Biology, Université Laval, Québec, Canada
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17
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Wang P, Wang J, Elberling B, Yang L, Chen W, Song L, Yan Y, Wang S, Pan J, He Y, Niu S. Increased annual methane uptake driven by warmer winters in an alpine meadow. GLOBAL CHANGE BIOLOGY 2022; 28:3246-3259. [PMID: 35122381 DOI: 10.1111/gcb.16120] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 01/27/2022] [Accepted: 01/29/2022] [Indexed: 06/14/2023]
Abstract
Pronounced nongrowing season warming and changes in soil freeze-thaw (F-T) cycles can dramatically alter net methane (CH4 ) exchange rates between soils and the atmosphere. However, the magnitudes and drivers of warming impacts on CH4 uptake in different stages of the F-T cycle are poorly understood in cold alpine ecosystems, which have been found to be a net sink of atmospheric CH4 . Here, we reported a year-round ecosystem daily CH4 uptake in an alpine meadow on the Qinghai-Tibetan Plateau after a 5-year warming experiment that included a control, a low-level warming treatment (+2.4℃ at 5 cm soil depth), and a high-level warming treatment (+4.5℃ at 5 cm soil depth). We found that warming shortened the F-T cycle under the low-level warming and soils did not freeze under the high-level warming. Although both warming treatments increased the mean CH4 uptake rate, only the high-level warming significantly increased annual CH4 uptake compared to the control. The warming-induced stimulation of CH4 uptake mainly occurred in the cold season, which was mostly during spring thaw under low-level warming and during the frozen winter under high-level warming due to a longer period with thawed soil. We also found that warming significantly stimulated daily CH4 uptake mainly by reducing near-surface soil water content in the warm season, whereas both soil water content and temperature controlled daily CH4 uptake in different ways during the autumn freeze, frozen winter, and spring thaw periods of the control. Our study revealed a strong warming effect on CH4 uptake during the entire F-T cycle in the alpine meadow, especially the unfrozen winter. Our results also suggested the important roles of soil pH, available phosphorus, and methanotroph abundance in regulating annual CH4 uptake in response to warming, which should be incorporated into biogeochemical models for accurately forecasting CH4 fluxes under future climate scenarios.
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Affiliation(s)
- Peiyan Wang
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Jinsong Wang
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Bo Elberling
- Center for Permafrost (CENPERM), Department of Geoscience and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
| | - Lu Yang
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Weinan Chen
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Lei Song
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Yingjie Yan
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Song Wang
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Junxiao Pan
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Yunlong He
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Shuli Niu
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
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18
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Keuschnig C, Larose C, Rudner M, Pesqueda A, Doleac S, Elberling B, Björk RG, Klemedtsson L, Björkman MP. Reduced methane emissions in former permafrost soils driven by vegetation and microbial changes following drainage. GLOBAL CHANGE BIOLOGY 2022; 28:3411-3425. [PMID: 35285570 PMCID: PMC9314937 DOI: 10.1111/gcb.16137] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 01/12/2022] [Indexed: 06/14/2023]
Abstract
In Arctic regions, thawing permafrost soils are projected to release 50 to 250 Gt of carbon by 2100. This data is mostly derived from carbon-rich wetlands, although 71% of this carbon pool is stored in faster-thawing mineral soils, where ecosystems close to the outer boundaries of permafrost regions are especially vulnerable. Although extensive data exists from currently thawing sites and short-term thawing experiments, investigations of the long-term changes following final thaw and co-occurring drainage are scarce. Here we show ecosystem changes at two comparable tussock tundra sites with distinct permafrost thaw histories, representing 15 and 25 years of natural drainage, that resulted in a 10-fold decrease in CH4 emissions (3.2 ± 2.2 vs. 0.3 ± 0.4 mg C-CH4 m-2 day-1 ), while CO2 emissions were comparable. These data extend the time perspective from earlier studies based on short-term experimental drainage. The overall microbial community structures did not differ significantly between sites, although the drier top soils at the most advanced site led to a loss of methanogens and their syntrophic partners in surface layers while the abundance of methanotrophs remained unchanged. The resulting deeper aeration zones likely increased CH4 oxidation due to the longer residence time of CH4 in the oxidation zone, while the observed loss of aerenchyma plants reduced CH4 diffusion from deeper soil layers directly to the atmosphere. Our findings highlight the importance of including hydrological, vegetation and microbial specific responses when studying long-term effects of climate change on CH4 emissions and underscores the need for data from different soil types and thaw histories.
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Affiliation(s)
- Christoph Keuschnig
- Environmental Microbial GenomicsLaboratoire AmpereEcole Centrale de LyonEcullyFrance
| | - Catherine Larose
- Environmental Microbial GenomicsLaboratoire AmpereEcole Centrale de LyonEcullyFrance
| | - Mario Rudner
- Department of Earth SciencesUniversity of GothenburgGothenburgSweden
| | - Argus Pesqueda
- Department of Earth SciencesUniversity of GothenburgGothenburgSweden
- Present address:
Center for Ecological Research and Forestry Applications (CREAF)‐Edifici CUniversitat Autonoma de BarcelonaBellaterra, BarcelonaSpain
| | - Stéphane Doleac
- Department of Earth SciencesUniversity of GothenburgGothenburgSweden
- Ecole PolytechniquePalaiseauFrance
| | - Bo Elberling
- Center for Permafrost (CENPERM)Department of Geosciences and Natural Resource ManagementUniversity of CopenhagenCopenhagenDenmark
| | - Robert G. Björk
- Department of Earth SciencesUniversity of GothenburgGothenburgSweden
- Gothenburg Global Biodiversity CentreGothenburgSweden
| | - Leif Klemedtsson
- Department of Earth SciencesUniversity of GothenburgGothenburgSweden
| | - Mats P. Björkman
- Department of Earth SciencesUniversity of GothenburgGothenburgSweden
- Gothenburg Global Biodiversity CentreGothenburgSweden
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19
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Scheller JH, Mastepanov M, Christensen TR. Toward UAV-based methane emission mapping of Arctic terrestrial ecosystems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 819:153161. [PMID: 35051474 DOI: 10.1016/j.scitotenv.2022.153161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 01/09/2022] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
Methane is an important greenhouse gas, and emissions are expected to rise in Arctic wetland ecosystems when temperatures increase due to climate change. However, current emission estimates are associated with large uncertainties because methane shows high spatial variability. A central problem is that existing methods are often spatially restricted due to limitations in access, cost, power availability, and in need of high maintenance levels. Our study explores how a setup consisting of an unmanned aerial vehicle and a high-precision trace gas analyzer can complement well-established methods, like mobile flux chambers and eddy covariance towers, by providing independent maps of spatial variability in emissions at the landscape scale. In Zackenberg Valley, Northeast Greenland, we mapped concentration measurements from a high-precision trace gas analyzer with a reported precision of 0.6 parts per billion in a high-Arctic tundra fen ecosystem. We connected the analyzer via a long tube to a consumer-grade quadcopter, finding that the combined setup could differentiate near-surface methane concentrations of less than 5 parts per billion within a few meters under favorable weather conditions. Five of ten campaigns showed that relative methane concentration hot spots and cold spots significantly correlated with areas showing relatively high and low emissions (ranging from 1.40 to 7.4 mg m-2 h-1) during study campaigns in previous years. Concurrent measurements in a stationary automated chamber setup showed comparatively low methane emissions (~0.1 to 3.9 mg m-2 h-1) compared to previous years, indicating that a further improved UAV-analyzer setup could demonstrate clear differences in an ecosystem where methane emissions are generally higher. Calm conditions with some degree of air mixing near the surface were best suited for the mapping. Windy and wet conditions should be avoided, both for the reliability of the mapping and for safely navigating the unmanned aerial vehicle.
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Affiliation(s)
- Johan H Scheller
- Department of Ecoscience, Aarhus University, Frederiksborgvej 399, DK-4000 Roskilde, Denmark.
| | - Mikhail Mastepanov
- Department of Ecoscience, Aarhus University, Frederiksborgvej 399, DK-4000 Roskilde, Denmark; Oulanka Research Station, University of Oulu, PO Box 8000, FI-90014, Finland.
| | - Torben R Christensen
- Department of Ecoscience, Aarhus University, Frederiksborgvej 399, DK-4000 Roskilde, Denmark; Oulanka Research Station, University of Oulu, PO Box 8000, FI-90014, Finland.
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20
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Utilizing Earth Observations of Soil Freeze/Thaw Data and Atmospheric Concentrations to Estimate Cold Season Methane Emissions in the Northern High Latitudes. REMOTE SENSING 2021. [DOI: 10.3390/rs13245059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The northern wetland methane emission estimates have large uncertainties. Inversion models are a qualified method to estimate the methane fluxes and emissions in northern latitudes but when atmospheric observations are sparse, the models are only as good as their a priori estimates. Thus, improving a priori estimates is a competent way to reduce uncertainties and enhance emission estimates in the sparsely sampled regions. Here, we use a novel way to integrate remote sensing soil freeze/thaw (F/T) status from SMOS satellite to better capture the seasonality of methane emissions in the northern high latitude. The SMOS F/T data provide daily information of soil freezing state in the northern latitudes, and in this study, the data is used to define the cold season in the high latitudes and, thus, improve our knowledge of the seasonal cycle of biospheric methane fluxes. The SMOS F/T data is implemented to LPX-Bern DYPTOP model estimates and the modified fluxes are used as a biospheric a priori in the inversion model CarbonTracker Europe-CH4. The implementation of the SMOS F/T soil state is shown to be beneficial in improving the inversion model’s cold season biospheric flux estimates. Our results show that cold season biospheric CH4 emissions in northern high latitudes are approximately 0.60 Tg lower than previously estimated, which corresponds to 17% reduction in the cold season biospheric emissions. This reduction is partly compensated by increased anthropogenic emissions in the same area (0.23 Tg), and the results also indicates that the anthropogenic emissions could have even larger contribution in cold season than estimated here.
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21
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Chen Y, Liu A, Cheng X. Vegetation grows more luxuriantly in Arctic permafrost drained lake basins. GLOBAL CHANGE BIOLOGY 2021; 27:5865-5876. [PMID: 34411382 PMCID: PMC9291482 DOI: 10.1111/gcb.15853] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 08/15/2021] [Indexed: 05/05/2023]
Abstract
As Arctic warming, permafrost thawing, and thermokarst development intensify, increasing evidence suggests that the frequency and magnitude of thermokarst lake drainage events are increasing. Presently, we lack a quantitative understanding of vegetation dynamics in drained lake basins, which is necessary to assess the extent to which plant growth in thawing ecosystems will offset the carbon released from permafrost. In this study, continuous satellite observations were used to detect thermokarst lake drainage events in northern Alaska over the past 20 years, and an advanced temporal segmentation and change detection algorithm allowed us to determine the year of drainage for each lake. Quantitative analysis showed that the greenness (normalized difference vegetation index [NDVI]) of tundra vegetation growing on wet and nutrient-rich lake sediments increased approximately 10 times faster than that of the peripheral vegetation. It takes approximately 5 years (4-6 years for the 25%-75% range) for the drainage lake area to reach the greenness level of the peripheral vegetation. Eventually, the NDVI values of the drained lake basins were 0.15 (or 25%) higher than those of the surrounding areas. In addition, we found less lush vegetation in the floodplain drained lake basins, possibly due to water logging. We further explored the key environmental drivers affecting vegetation dynamics in and around the drained lake basins. The results showed that our multivariate regression model well simulated the growth dynamics of the drainage lake ecosystem ( Radj2=.73 , p < .001) and peripheral vegetation ( Radj2=.68 , p < .001). Among climate variables, moisture variables were more influential than temperature variables, indicating that vegetation growth in this area is susceptible to water stress. Our study provides valuable information for better modeling of vegetation dynamics in thermokarst lake areas and provides new insights into Arctic greening and carbon balance studies as thermokarst lake drainage intensifies.
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Affiliation(s)
- Yating Chen
- State Key Laboratory of Remote Sensing Science, and College of Global Change and Earth System ScienceBeijing Normal UniversityBeijingChina
- School of Geospatial Engineering and ScienceSun Yat‐Sen UniversityZhuhaiChina
| | - Aobo Liu
- State Key Laboratory of Remote Sensing Science, and College of Global Change and Earth System ScienceBeijing Normal UniversityBeijingChina
- School of Geospatial Engineering and ScienceSun Yat‐Sen UniversityZhuhaiChina
| | - Xiao Cheng
- School of Geospatial Engineering and ScienceSun Yat‐Sen UniversityZhuhaiChina
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22
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Impact of river channel lateral migration on microbial communities across a discontinuous permafrost floodplain. Appl Environ Microbiol 2021; 87:e0133921. [PMID: 34347514 DOI: 10.1128/aem.01339-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Permafrost soils store approximately twice the amount of carbon currently present in Earth's atmosphere and are acutely impacted by climate change due to the polar amplification of increasing global temperature. Many organic-rich permafrost sediments are located on large river floodplains, where river channel migration periodically erodes and re-deposits the upper tens of meters of sediment. Channel migration exerts a first-order control on the geographic distribution of permafrost and floodplain stratigraphy and thus may affect microbial habitats. To examine how river channel migration in discontinuous permafrost environments affects microbial community composition, we used amplicon sequencing of the 16S rRNA gene on sediment samples from floodplain cores and exposed riverbanks along the Koyukuk River, a large tributary of the Yukon River in west-central Alaska. Microbial communities are sensitive to permafrost thaw: communities found in deep samples thawed by the river closely resembled near-surface active layer communities in non-metric multidimensional scaling analyses but did not resemble floodplain permafrost communities at the same depth. Microbial communities also displayed lower diversity and evenness in permafrost than in both the active layer and permafrost-free point bars recently deposited by river channel migration. Taxonomic assignments based on 16S and quantitative PCR for the methyl-coenzyme M reductase functional gene demonstrated that methanogens and methanotrophs are abundant in older permafrost-bearing deposits, but not in younger, non-permafrost point bar deposits. The results suggested that river migration, which regulates the distribution of permafrost, also modulates the distribution of microbes potentially capable of producing and consuming methane on the Koyukuk River floodplain. Importance Arctic lowlands contain large quantities of soil organic carbon that is currently sequestered in permafrost. With rising temperatures, permafrost thaw may allow this carbon to be consumed by microbial communities and released to the atmosphere as carbon dioxide or methane. We used gene sequencing to determine the microbial communities present in the floodplain of a river running through discontinuous permafrost. We found the river's lateral movement across its floodplain influences the occurrence of certain microbial communities-in particular, methane-cycling microbes were present on the older, permafrost-bearing eroding riverbank but absent on the newly deposited river bars. Riverbank sediment had microbial communities more similar to the floodplain active layer than permafrost samples from the same depth. Therefore, spatial patterns of river migration influence the distribution of microbial taxa relevant to the warming Arctic climate.
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23
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Knox SH, Bansal S, McNicol G, Schafer K, Sturtevant C, Ueyama M, Valach AC, Baldocchi D, Delwiche K, Desai AR, Euskirchen E, Liu J, Lohila A, Malhotra A, Melling L, Riley W, Runkle BRK, Turner J, Vargas R, Zhu Q, Alto T, Fluet-Chouinard E, Goeckede M, Melton JR, Sonnentag O, Vesala T, Ward E, Zhang Z, Feron S, Ouyang Z, Alekseychik P, Aurela M, Bohrer G, Campbell DI, Chen J, Chu H, Dalmagro HJ, Goodrich JP, Gottschalk P, Hirano T, Iwata H, Jurasinski G, Kang M, Koebsch F, Mammarella I, Nilsson MB, Ono K, Peichl M, Peltola O, Ryu Y, Sachs T, Sakabe A, Sparks JP, Tuittila ES, Vourlitis GL, Wong GX, Windham-Myers L, Poulter B, Jackson RB. Identifying dominant environmental predictors of freshwater wetland methane fluxes across diurnal to seasonal time scales. GLOBAL CHANGE BIOLOGY 2021; 27:3582-3604. [PMID: 33914985 DOI: 10.1111/gcb.15661] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 12/24/2020] [Indexed: 06/12/2023]
Abstract
While wetlands are the largest natural source of methane (CH4 ) to the atmosphere, they represent a large source of uncertainty in the global CH4 budget due to the complex biogeochemical controls on CH4 dynamics. Here we present, to our knowledge, the first multi-site synthesis of how predictors of CH4 fluxes (FCH4) in freshwater wetlands vary across wetland types at diel, multiday (synoptic), and seasonal time scales. We used several statistical approaches (correlation analysis, generalized additive modeling, mutual information, and random forests) in a wavelet-based multi-resolution framework to assess the importance of environmental predictors, nonlinearities and lags on FCH4 across 23 eddy covariance sites. Seasonally, soil and air temperature were dominant predictors of FCH4 at sites with smaller seasonal variation in water table depth (WTD). In contrast, WTD was the dominant predictor for wetlands with smaller variations in temperature (e.g., seasonal tropical/subtropical wetlands). Changes in seasonal FCH4 lagged fluctuations in WTD by ~17 ± 11 days, and lagged air and soil temperature by median values of 8 ± 16 and 5 ± 15 days, respectively. Temperature and WTD were also dominant predictors at the multiday scale. Atmospheric pressure (PA) was another important multiday scale predictor for peat-dominated sites, with drops in PA coinciding with synchronous releases of CH4 . At the diel scale, synchronous relationships with latent heat flux and vapor pressure deficit suggest that physical processes controlling evaporation and boundary layer mixing exert similar controls on CH4 volatilization, and suggest the influence of pressurized ventilation in aerenchymatous vegetation. In addition, 1- to 4-h lagged relationships with ecosystem photosynthesis indicate recent carbon substrates, such as root exudates, may also control FCH4. By addressing issues of scale, asynchrony, and nonlinearity, this work improves understanding of the predictors and timing of wetland FCH4 that can inform future studies and models, and help constrain wetland CH4 emissions.
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Affiliation(s)
- Sara H Knox
- Department of Geography, The University of British Columbia, Vancouver, BC, Canada
| | - Sheel Bansal
- Northern Prairie Wildlife Research Center, U.S. Geological Survey, Jamestown, ND, USA
| | - Gavin McNicol
- Department of Earth System Science, Stanford University, Stanford, CA, USA
| | - Karina Schafer
- Department of Earth and Environmental Science, Rutgers University Newark, New Brunswick, NJ, USA
| | - Cove Sturtevant
- National Ecological Observatory Network, Battelle, Boulder, CO, USA
| | - Masahito Ueyama
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Japan
| | - Alex C Valach
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, USA
| | - Dennis Baldocchi
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, USA
| | - Kyle Delwiche
- Department of Earth System Science, Stanford University, Stanford, CA, USA
| | - Ankur R Desai
- Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Eugenie Euskirchen
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, USA
| | - Jinxun Liu
- Western Geographic Science Center, U.S. Geological Survey, Moffett Field, CA, USA
| | - Annalea Lohila
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
- Climate System Research, Finnish Meteorological Institute, Helsinki, Finland
| | - Avni Malhotra
- Department of Earth System Science, Stanford University, Stanford, CA, USA
| | - Lulie Melling
- Sarawak Tropical Peat Research Institute, Sarawak, Malaysia
| | - William Riley
- Earth and Environmental Sciences Area, Lawrence Berkeley National Lab, Berkeley, CA, USA
| | - Benjamin R K Runkle
- Department of Biological & Agricultural Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Jessica Turner
- Freshwater and Marine Science, University of Wisconsin-Madison, Madison, WI, USA
| | - Rodrigo Vargas
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE, USA
| | - Qing Zhu
- Earth and Environmental Sciences Area, Lawrence Berkeley National Lab, Berkeley, CA, USA
| | - Tuula Alto
- Climate System Research, Finnish Meteorological Institute, Helsinki, Finland
| | | | - Mathias Goeckede
- Department of Biogeochemical Signals, Max Planck Institute for Biogeochemistry, Jena, Germany
| | - Joe R Melton
- Climate Research Division, Environment and Climate Change Canada, Victoria, BC, Canada
| | - Oliver Sonnentag
- Département de Géographie, Université de Montréal, Montréal, QC, Canada
| | - Timo Vesala
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
- Yugra State University, Khanty-Mansiysk, Russia
| | - Eric Ward
- Wetland and Aquatic Research Center, U.S. Geological Survey, Lafayette, LA, USA
| | - Zhen Zhang
- Department of Geographical Sciences, University of Maryland, College Park, MD, USA
| | - Sarah Feron
- Department of Earth System Science, Stanford University, Stanford, CA, USA
- Department of Physics, University of Santiago, Santiago de Chile, Chile
| | - Zutao Ouyang
- Department of Earth System Science, Stanford University, Stanford, CA, USA
| | | | - Mika Aurela
- Climate System Research, Finnish Meteorological Institute, Helsinki, Finland
| | - Gil Bohrer
- Department of Civil, Environmental & Geodetic Engineering, Ohio State University, Columbus, OH, USA
| | | | - Jiquan Chen
- Department of Geography, Environment, and Spatial Sciences, & Center for Global Change and Earth Observations, Michigan State University, East Lansing, MI, USA
| | - Housen Chu
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Lab, Berkeley, CA, USA
| | | | | | - Pia Gottschalk
- GFZ German Research Centre for Geosciences, Potsdam, Germany
| | - Takashi Hirano
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Hiroki Iwata
- Department of Environmental Science, Faculty of Science, Shinshu University, Matsumoto, Japan
| | | | - Minseok Kang
- National Center for Agro Meteorology, Seoul, South Korea
| | | | - Ivan Mammarella
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - Mats B Nilsson
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Keisuke Ono
- Institute for Agro-Environmental Sciences, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Matthias Peichl
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Olli Peltola
- Climate System Research, Finnish Meteorological Institute, Helsinki, Finland
| | - Youngryel Ryu
- Department of Landscape Architecture and Rural Systems Engineering, Seoul National University, Seoul, South Korea
| | - Torsten Sachs
- GFZ German Research Centre for Geosciences, Potsdam, Germany
| | | | - Jed P Sparks
- Department of Ecology and Evolutionary Biology, Cornell, Ithaca, NY, USA
| | | | | | - Guan X Wong
- Sarawak Tropical Peat Research Institute, Sarawak, Malaysia
| | | | - Benjamin Poulter
- Biospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - Robert B Jackson
- Department of Earth System Science, Stanford University, Stanford, CA, USA
- Woods Institute for the Environment, Stanford University, Stanford, CA, USA
- Precourt Institute for Energy, Stanford University, Stanford, CA, USA
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24
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The Predominance of Nongrowing Season Emissions to the Annual Methane Budget of a Semiarid Alpine Meadow on the Northeastern Qinghai-Tibetan Plateau. Ecosystems 2021. [DOI: 10.1007/s10021-021-00669-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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25
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Wang J, Quan Q, Chen W, Tian D, Ciais P, Crowther TW, Mack MC, Poulter B, Tian H, Luo Y, Wen X, Yu G, Niu S. Increased CO 2 emissions surpass reductions of non-CO 2 emissions more under higher experimental warming in an alpine meadow. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 769:144559. [PMID: 33485199 DOI: 10.1016/j.scitotenv.2020.144559] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 11/21/2020] [Accepted: 12/13/2020] [Indexed: 06/12/2023]
Abstract
It is well documented that warming can accelerate greenhouse gas (GHG) emissions, further inducing a positive feedback and reinforcing future climate warming. However, how different kinds of GHGs respond to various warming magnitudes remains largely unclear, especially in the cold regions that are more sensitive to climate warming. Here, we concurrently measured carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) fluxes and their total balance in an alpine meadow in response to three levels of warming (ambient, +1.5 °C, +3.0 °C). We found warming-induced increases in CH4 uptake, decreases in N2O emissions and increases in CO2 emissions at the annual basis. Expressed as CO2-equivalents with a global warming potential of 100 years (GWP100), the enhancement of CH4 uptake and reduction of N2O emissions offset only 9% of the warming-induced increase in CO2 emissions for 1.5 °C warming, and only 7% for 3.0 °C warming. CO2 emissions were strongly stimulated, leading to a significantly positive feedback to climate system, for 3.0 °C warming but less for 1.5 °C warming. The warming with 3.0 °C altered the total GHG balance mainly by stimulating CO2 emissions in the non-growing season due to warmer soil temperatures, longer unfrozen period, and increased soil water content. The findings provide an empirical evidence that warming beyond global 2 °C target can trigger a positive GHG-climate feedback and highlight the contribution from non-growing season to this positive feedback loop in cold ecosystems.
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Affiliation(s)
- Jinsong Wang
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, PR China; Center for Ecosystem Science and Society and the Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Quan Quan
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, PR China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Weinan Chen
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, PR China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Dashuan Tian
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Philippe Ciais
- Laboratoire des Sciences du Climat et de I'Environnement (LSCE), CEA CNRS UVSQ, 91191 Gif-sur-Yvette, France
| | - Thomas W Crowther
- Institute of Integrative Biology, Department of Environment Systems Science, ETH Zürich, 8092 Zürich, Switzerland
| | - Michelle C Mack
- Center for Ecosystem Science and Society and the Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | | | - Hanqin Tian
- International Center for Climate and Global Change Research, School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL 36849, USA
| | - Yiqi Luo
- Center for Ecosystem Science and Society and the Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Xuefa Wen
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, PR China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Guirui Yu
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, PR China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Shuli Niu
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, PR China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, PR China.
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Chang KY, Riley WJ, Knox SH, Jackson RB, McNicol G, Poulter B, Aurela M, Baldocchi D, Bansal S, Bohrer G, Campbell DI, Cescatti A, Chu H, Delwiche KB, Desai AR, Euskirchen E, Friborg T, Goeckede M, Helbig M, Hemes KS, Hirano T, Iwata H, Kang M, Keenan T, Krauss KW, Lohila A, Mammarella I, Mitra B, Miyata A, Nilsson MB, Noormets A, Oechel WC, Papale D, Peichl M, Reba ML, Rinne J, Runkle BRK, Ryu Y, Sachs T, Schäfer KVR, Schmid HP, Shurpali N, Sonnentag O, Tang ACI, Torn MS, Trotta C, Tuittila ES, Ueyama M, Vargas R, Vesala T, Windham-Myers L, Zhang Z, Zona D. Substantial hysteresis in emergent temperature sensitivity of global wetland CH 4 emissions. Nat Commun 2021; 12:2266. [PMID: 33859182 PMCID: PMC8050324 DOI: 10.1038/s41467-021-22452-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 03/15/2021] [Indexed: 11/21/2022] Open
Abstract
Wetland methane (CH4) emissions ([Formula: see text]) are important in global carbon budgets and climate change assessments. Currently, [Formula: see text] projections rely on prescribed static temperature sensitivity that varies among biogeochemical models. Meta-analyses have proposed a consistent [Formula: see text] temperature dependence across spatial scales for use in models; however, site-level studies demonstrate that [Formula: see text] are often controlled by factors beyond temperature. Here, we evaluate the relationship between [Formula: see text] and temperature using observations from the FLUXNET-CH4 database. Measurements collected across the globe show substantial seasonal hysteresis between [Formula: see text] and temperature, suggesting larger [Formula: see text] sensitivity to temperature later in the frost-free season (about 77% of site-years). Results derived from a machine-learning model and several regression models highlight the importance of representing the large spatial and temporal variability within site-years and ecosystem types. Mechanistic advancements in biogeochemical model parameterization and detailed measurements in factors modulating CH4 production are thus needed to improve global CH4 budget assessments.
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Affiliation(s)
- Kuang-Yu Chang
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - William J Riley
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Sara H Knox
- Department of Geography, The University of British Columbia, Vancouver, BC, Canada
| | - Robert B Jackson
- Department of Earth System Science, Stanford University, Stanford, CA, USA
- Woods Institute for the Environment and Precourt Institute for Energy, Stanford, CA, USA
| | - Gavin McNicol
- Department of Earth System Science, Stanford University, Stanford, CA, USA
| | - Benjamin Poulter
- NASA Goddard Space Flight Center, Biospheric Sciences Laboratory, Greenbelt, MD, USA
| | - Mika Aurela
- Finnish Meteorological Institute, Helsinki, Finland
| | - Dennis Baldocchi
- Department of Environmental Science, Policy & Management, UC Berkeley, Berkeley, CA, USA
| | - Sheel Bansal
- U.S. Geological Survey, Northern Prairie Wildlife Research Center, Jamestown, ND, USA
| | - Gil Bohrer
- Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, Columbus, OH, USA
| | | | | | - Housen Chu
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Kyle B Delwiche
- Department of Earth System Science, Stanford University, Stanford, CA, USA
| | - Ankur R Desai
- Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Eugenie Euskirchen
- University of Alaska Fairbanks, Institute of Arctic Biology, Fairbanks, AK, USA
| | - Thomas Friborg
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen K, Denmark
| | | | - Manuel Helbig
- School of Geography and Earth Sciences, McMaster University, Hamilton, ON, Canada
- Département de Géographie & Centre d'Études Nordiques, Montréal, QC, Canada
| | - Kyle S Hemes
- Woods Institute for the Environment, Stanford University, Stanford, CA, USA
| | - Takashi Hirano
- Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
| | - Hiroki Iwata
- Department of Environmental Science, Faculty of Science, Shinshu University, Matsumoto, Japan
| | - Minseok Kang
- National Center for AgroMeteorology, Seoul, South Korea
| | - Trevor Keenan
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Environmental Science, Policy & Management, UC Berkeley, Berkeley, CA, USA
| | - Ken W Krauss
- U.S. Geological Survey, Wetland and Aquatic Research Center, Lafayette, LA, USA
| | - Annalea Lohila
- Finnish Meteorological Institute, Helsinki, Finland
- Institute for Atmosphere and Earth System Research/Physics, Faculty of Science, University of Helsink, Helsinki, Finland
| | - Ivan Mammarella
- Institute for Atmosphere and Earth System Research/Physics, Faculty of Science, University of Helsink, Helsinki, Finland
| | - Bhaskar Mitra
- Department of Ecology and Conservation Biology, Texas A&M University, College Station, TX, USA
| | - Akira Miyata
- Institute for Agro-Environmental Sciences, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Mats B Nilsson
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Asko Noormets
- Department of Ecosystem Science and Management, Texas A&M University, College Station, TX, USA
| | - Walter C Oechel
- Department of Biology, San Diego State University, San Diego, CA, USA
| | - Dario Papale
- DIBAF, Università degli Studi della Tuscia, Largo dell'Università, Viterbo, Italy
| | - Matthias Peichl
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Michele L Reba
- United States Department of Agriculture, Agricultural Research Service, Delta Water Management Research Service, Jonesboro, AR, USA
| | - Janne Rinne
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Benjamin R K Runkle
- Department of Biological and Agricultural Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Youngryel Ryu
- Department of Landscape Architecture and Rural Systems Engineering, Seoul National University, Seoul, South Korea
| | - Torsten Sachs
- GFZ German Research Centre for Geoscience, Potsdam, Germany
| | - Karina V R Schäfer
- Department of Biological Sciences, Rutgers University Newark, Newark, NJ, USA
| | - Hans Peter Schmid
- Institute of Meteorology and Climatology - Atmospheric Environmental Research (IMK-IFU), Karlsruhe Institute of Technology (KIT), Garmisch-Partenkirchen, Germany
| | - Narasinha Shurpali
- Production Systems, Natural Resources Institute Finland, Maaninka, Finland
| | - Oliver Sonnentag
- Département de Géographie & Centre d'Études Nordiques, Montréal, QC, Canada
| | | | - Margaret S Torn
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Carlo Trotta
- DIBAF, Università degli Studi della Tuscia, Largo dell'Università, Viterbo, Italy
- Euro-Mediterranean Center on Climate Change, CMCC IAFES, Viterbo, Italy
| | | | - Masahito Ueyama
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka, Japan
| | - Rodrigo Vargas
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE, USA
| | - Timo Vesala
- Institute for Atmosphere and Earth System Research/Physics, Faculty of Science, University of Helsink, Helsinki, Finland
- Institute for Atmosphere and Earth System Research, Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | | | - Zhen Zhang
- Department of Geographical Sciences, University of Maryland, College Park, MD, USA
| | - Donatella Zona
- Department of Biology, San Diego State University, San Diego, CA, USA
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
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Roy Chowdhury T, Berns EC, Moon JW, Gu B, Liang L, Wullschleger SD, Graham DE. Temporal, Spatial, and Temperature Controls on Organic Carbon Mineralization and Methanogenesis in Arctic High-Centered Polygon Soils. Front Microbiol 2021; 11:616518. [PMID: 33505383 PMCID: PMC7829362 DOI: 10.3389/fmicb.2020.616518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 12/10/2020] [Indexed: 11/18/2022] Open
Abstract
Warming temperatures in continuous permafrost zones of the Arctic will alter both hydrological and geochemical soil conditions, which are strongly linked with heterotrophic microbial carbon (C) cycling. Heterogeneous permafrost landscapes are often dominated by polygonal features formed by expanding ice wedges: water accumulates in low centered polygons (LCPs), and water drains outward to surrounding troughs in high centered polygons (HCPs). These geospatial differences in hydrology cause gradients in biogeochemistry, soil C storage potential, and thermal properties. Presently, data quantifying carbon dioxide (CO2) and methane (CH4) release from HCP soils are needed to support modeling and evaluation of warming-induced CO2 and CH4 fluxes from tundra soils. This study quantifies the distribution of microbial CO2 and CH4 release in HCPs over a range of temperatures and draws comparisons to previous LCP studies. Arctic tundra soils were initially characterized for geochemical and hydraulic properties. Laboratory incubations at −2, +4, and +8°C were used to quantify temporal trends in CO2 and CH4 production from homogenized active layer organic and mineral soils in HCP centers and troughs, and methanogen abundance was estimated from mcrA gene measurements. Results showed that soil water availability, organic C, and redox conditions influence temporal dynamics and magnitude of gas production from HCP active layer soils during warming. At early incubation times (2–9 days), higher CO2 emissions were observed from HCP trough soils than from HCP center soils, but increased CO2 production occurred in center soils at later times (>20 days). HCP center soils did not support methanogenesis, but CH4-producing trough soils did indicate methanogen presence. Consistent with previous LCP studies, HCP organic soils showed increased CO2 and CH4 production with elevated water content, but HCP trough mineral soils produced more CH4 than LCP mineral soils. HCP mineral soils also released substantial CO2 but did not show a strong trend in CO2 and CH4 release with water content. Knowledge of temporal and spatial variability in microbial C mineralization rates of Arctic soils in response to warming are key to constraining uncertainties in predictive climate models.
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Affiliation(s)
- Taniya Roy Chowdhury
- Oak Ridge National Laboratory, Biosciences Division, Oak Ridge, TN, United States
| | - Erin C Berns
- Oak Ridge National Laboratory, Biosciences Division, Oak Ridge, TN, United States
| | - Ji-Won Moon
- Oak Ridge National Laboratory, Biosciences Division, Oak Ridge, TN, United States
| | - Baohua Gu
- Oak Ridge National Laboratory, Environmental Sciences Division, Oak Ridge, TN, United States
| | - Liyuan Liang
- Oak Ridge National Laboratory, Environmental Sciences Division, Oak Ridge, TN, United States
| | - Stan D Wullschleger
- Oak Ridge National Laboratory, Environmental Sciences Division, Oak Ridge, TN, United States.,Oak Ridge National Laboratory, Climate Change Science Institute, Oak Ridge, TN, United States
| | - David E Graham
- Oak Ridge National Laboratory, Biosciences Division, Oak Ridge, TN, United States
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Organohalide-Respiring Bacteria at the Heart of Anaerobic Metabolism in Arctic Wet Tundra Soils. Appl Environ Microbiol 2021; 87:AEM.01643-20. [PMID: 33187999 DOI: 10.1128/aem.01643-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 11/10/2020] [Indexed: 11/20/2022] Open
Abstract
Recent work revealed an active biological chlorine cycle in coastal Arctic tundra of northern Alaska. This raised the question of whether chlorine cycling was restricted to coastal areas or if these processes extended to inland tundra. The anaerobic process of organohalide respiration, carried out by specialized bacteria like Dehalococcoides, consumes hydrogen gas and acetate using halogenated organic compounds as terminal electron acceptors, potentially competing with methanogens that produce the greenhouse gas methane. We measured microbial community composition and soil chemistry along an ∼262-km coastal-inland transect to test for the potential of organohalide respiration across the Arctic Coastal Plain and studied the microbial community associated with Dehalococcoides to explore the ecology of this group and its potential to impact C cycling in the Arctic. Concentrations of brominated organic compounds declined sharply with distance from the coast, but the decrease in organic chlorine pools was more subtle. The relative abundances of Dehalococcoides were similar across the transect, except for being lower at the most inland site. Dehalococcoides correlated with other strictly anaerobic genera, plus some facultative ones, that had the genetic potential to provide essential resources (hydrogen, acetate, corrinoids, or organic chlorine). This community included iron reducers, sulfate reducers, syntrophic bacteria, acetogens, and methanogens, some of which might also compete with Dehalococcoides for hydrogen and acetate. Throughout the Arctic Coastal Plain, Dehalococcoides is associated with the dominant anaerobes that control fluxes of hydrogen, acetate, methane, and carbon dioxide. Depending on seasonal electron acceptor availability, organohalide-respiring bacteria could impact carbon cycling in Arctic wet tundra soils.IMPORTANCE Once considered relevant only in contaminated sites, it is now recognized that biological chlorine cycling is widespread in natural environments. However, linkages between chlorine cycling and other ecosystem processes are not well established. Species in the genus Dehalococcoides are highly specialized, using hydrogen, acetate, vitamin B12-like compounds, and organic chlorine produced by the surrounding community. We studied which neighbors might produce these essential resources for Dehalococcoides species. We found that Dehalococcoides species are ubiquitous across the Arctic Coastal Plain and are closely associated with a network of microbes that produce or consume hydrogen or acetate, including the most abundant anaerobic bacteria and methanogenic archaea. We also found organic chlorine and microbes that can produce these compounds throughout the study area. Therefore, Dehalococcoides could control the balance between carbon dioxide and methane (a more potent greenhouse gas) when suitable organic chlorine compounds are available to drive hydrogen and acetate uptake.
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Bao T, Xu X, Jia G, Billesbach DP, Sullivan RC. Much stronger tundra methane emissions during autumn freeze than spring thaw. GLOBAL CHANGE BIOLOGY 2021; 27:376-387. [PMID: 33118303 DOI: 10.1111/gcb.15421] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 10/25/2020] [Indexed: 06/11/2023]
Abstract
Warming in the Arctic has been more apparent in the non-growing season than in the typical growing season. In this context, methane (CH4 ) emissions in the non-growing season, particularly in the shoulder seasons, account for a substantial proportion of the annual budget. However, CH4 emissions in spring and autumn shoulders are often underestimated by land models and measurements due to limited data availability and unknown mechanisms. This study investigates CH4 emissions during spring thaw and autumn freeze using eddy covariance CH4 measurements from three Arctic sites with multi-year observations. We find that the shoulder seasons contribute to about a quarter (25.6 ± 2.3%, mean ± SD) of annual total CH4 emissions. Our study highlights the three to four times higher contribution of autumn freeze CH4 emission to total annual emission than that of spring thaw. Autumn freeze exhibits significantly higher CH4 flux (0.88 ± 0.03 mg m-2 hr-1 ) than spring thaw (0.48 ± 0.04 mg m-2 hr-1 ). The mean duration of autumn freeze (58.94 ± 26.39 days) is significantly longer than that of spring thaw (20.94 ± 7.79 days), which predominates the much higher cumulative CH4 emission during autumn freeze (1,212.31 ± 280.39 mg m-2 year-1 ) than that during spring thaw (307.39 ± 46.11 mg m-2 year-1 ). Near-surface soil temperatures cannot completely reflect the freeze-thaw processes in deeper soil layers and appears to have a hysteresis effect on CH4 emissions from early spring thaw to late autumn freeze. Therefore, it is necessary to consider commonalities and differences in CH4 emissions during spring thaw versus autumn freeze to accurately estimate CH4 source from tundra ecosystems for evaluating carbon-climate feedback in Arctic.
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Affiliation(s)
- Tao Bao
- Key Laboratory of Regional Climate-Environment for Temperate East Asia, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
| | - Xiyan Xu
- Key Laboratory of Regional Climate-Environment for Temperate East Asia, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
| | - Gensuo Jia
- Key Laboratory of Regional Climate-Environment for Temperate East Asia, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
| | - David P Billesbach
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Ryan C Sullivan
- Environmental Science Division, Argonne National Laboratory, Lemont, IL, USA
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30
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Methane Content and Emission in the Permafrost Landscapes of Western Yamal, Russian Arctic. GEOSCIENCES 2020. [DOI: 10.3390/geosciences10100412] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We present the results of studies of the methane content in soils of the active layer and underlying permafrost, as well as data on the emission of methane into the atmosphere in the dominant landscapes of typical tundra of the western coast of the Yamal Peninsula. A detailed landscape map of the study area was compiled, the dominant types of landscapes were determined, and vegetation cover was described. We determined that a high methane content is characteristic of the wet landscapes: peat bogs within the floodplains, water tracks, and lake basins. Average values of the methane content in the active layer for such landscapes varied from 2.4 to 3.5 mL (CH4)/kg, with a maximum of 9.0 mL (CH4)/kg. The distribution of methane in studied sections is characterized by an increase in its concentration with depth. This confirms the diffuse mechanism of methane transport in the active layer and emission of methane into the atmosphere. The transition zone of the upper permafrost contains 2.5–5-times more methane than the active layer and may become a significant source of methane during the anticipated permafrost degradation. Significant fluxes of methane into the atmosphere of 2.6 mg (CH4) * m−2 * h−1 are characteristic of the flooded landscapes of peat bogs, water tracks, and lake basins, which occupy approximately 45% of the typical tundra area.
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31
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Olid C, Klaminder J, Monteux S, Johansson M, Dorrepaal E. Decade of experimental permafrost thaw reduces turnover of young carbon and increases losses of old carbon, without affecting the net carbon balance. GLOBAL CHANGE BIOLOGY 2020; 26:5886-5898. [PMID: 32681580 DOI: 10.1111/gcb.15283] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 06/18/2020] [Indexed: 06/11/2023]
Abstract
Thicker snowpacks and their insulation effects cause winter-warming and invoke thaw of permafrost ecosystems. Temperature-dependent decomposition of previously frozen carbon (C) is currently considered one of the strongest feedbacks between the Arctic and the climate system, but the direction and magnitude of the net C balance remains uncertain. This is because winter effects are rarely integrated with C fluxes during the snow-free season and because predicting the net C balance from both surface processes and thawing deep layers remains challenging. In this study, we quantified changes in the long-term net C balance (net ecosystem production) in a subarctic peat plateau subjected to 10 years of experimental winter-warming. By combining 210 Pb and 14 Cdating of peat cores with peat growth models, we investigated thawing effects on year-round primary production and C losses through respiration and leaching from both shallow and deep peat layers. Winter-warming and permafrost thaw had no effect on the net C balance, but strongly affected gross C fluxes. Carbon losses through decomposition from the upper peat were reduced as thawing of permafrost induced surface subsidence and subsequent waterlogging. However, primary production was also reduced likely due to a strong decline in bryophytes cover while losses from the old C pool almost tripled, caused by the deepened active layer. Our findings highlight the need to estimate long-term responses of whole-year production and decomposition processes to thawing, both in shallow and deep soil layers, as they may contrast and lead to unexpected net effects on permafrost C storage.
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Affiliation(s)
- Carolina Olid
- Climate Impacts Research Centre (CIRC), Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
| | - Jonatan Klaminder
- Climate Impacts Research Centre (CIRC), Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
| | - Sylvain Monteux
- Climate Impacts Research Centre (CIRC), Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
- Department of Soil and Environment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Margareta Johansson
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
- Royal Swedish Academy of Science, Stockholm, Sweden
| | - Ellen Dorrepaal
- Climate Impacts Research Centre (CIRC), Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
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32
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Arndt KA, Lipson DA, Hashemi J, Oechel WC, Zona D. Snow melt stimulates ecosystem respiration in Arctic ecosystems. GLOBAL CHANGE BIOLOGY 2020; 26:5042-5051. [PMID: 32602589 DOI: 10.1111/gcb.15193] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 05/11/2020] [Indexed: 06/11/2023]
Abstract
Cold seasons in Arctic ecosystems are increasingly important to the annual carbon balance of these vulnerable ecosystems. Arctic winters are largely harsh and inaccessible leading historic data gaps during that time. Until recently, cold seasons have been assumed to have negligible impacts on the annual carbon balance but as data coverage increases and the Arctic warms, the cold season has been shown to account for over half of annual methane (CH4 ) emissions and can offset summer photosynthetic carbon dioxide (CO2 ) uptake. Freeze-thaw cycle dynamics play a critical role in controlling cold season CO2 and CH4 loss, but the relationship has not been extensively studied. Here, we analyze freeze-thaw processes through in situ CO2 and CH4 fluxes in conjunction with soil cores for physical structure and porewater samples for redox biogeochemistry. We find a movement of water toward freezing fronts in soil cores, leaving air spaces in soils, which allows for rapid infiltration of oxygen-rich snow melt in spring as shown by oxidized iron in porewater. The snow melt period coincides with rising ecosystem respiration and can offset up to 41% of the summer CO2 uptake. Our study highlights this important seasonal process and shows spring greenhouse gas emissions are largely due to production from respiration instead of only bursts of stored gases. Further warming is projected to result in increases of snowpack and deeper thaws, which could increase this ecosystem respiration dominate snow melt period causing larger greenhouse gas losses during spring.
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Affiliation(s)
- Kyle A Arndt
- Department of Biology, San Diego State University, San Diego, CA, USA
- Department of Land, Air, and Water Resources, University of California at Davis, Davis, CA, USA
| | - David A Lipson
- Department of Biology, San Diego State University, San Diego, CA, USA
| | - Josh Hashemi
- Department of Biology, San Diego State University, San Diego, CA, USA
- Department of Land, Air, and Water Resources, University of California at Davis, Davis, CA, USA
| | - Walter C Oechel
- Department of Biology, San Diego State University, San Diego, CA, USA
- Department of Geography, University of Exeter, Exeter, UK
| | - Donatella Zona
- Department of Biology, San Diego State University, San Diego, CA, USA
- Department of Plant and Animal Sciences, University of Sheffield, Sheffield, UK
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Carotenuto F, Brilli L, Gioli B, Gualtieri G, Vagnoli C, Mazzola M, Viola AP, Vitale V, Severi M, Traversi R, Zaldei A. Long-Term Performance Assessment of Low-Cost Atmospheric Sensors in the Arctic Environment. SENSORS (BASEL, SWITZERLAND) 2020; 20:E1919. [PMID: 32235527 PMCID: PMC7180591 DOI: 10.3390/s20071919] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 03/27/2020] [Accepted: 03/28/2020] [Indexed: 11/17/2022]
Abstract
The Arctic is an important natural laboratory that is extremely sensitive to climatic changes and its monitoring is, therefore, of great importance. Due to the environmental extremes it is often hard to deploy sensors and observations are limited to a few sparse observation points limiting the spatial and temporal coverage of the Arctic measurement. Given these constraints the possibility of deploying a rugged network of low-cost sensors remains an interesting and convenient option. The present work validates for the first time a low-cost sensor array (AIRQino) for monitoring basic meteorological parameters and atmospheric composition in the Arctic (air temperature, relative humidity, particulate matter, and CO2). AIRQino was deployed for one year in the Svalbard archipelago and its outputs compared with reference sensors. Results show good agreement with the reference meteorological parameters (air temperature (T) and relative humidity (RH)) with correlation coefficients above 0.8 and small absolute errors (≈1 °C for temperature and ≈6% for RH). Particulate matter (PM) low-cost sensors show a good linearity (r2 ≈ 0.8) and small absolute errors for both PM2.5 and PM10 (≈1 µg m-3 for PM2.5 and ≈3 µg m-3 for PM10), while overall accuracy is impacted both by the unknown composition of the local aerosol, and by high humidity conditions likely generating hygroscopic effects. CO2 exhibits a satisfying agreement with r2 around 0.70 and an absolute error of ≈23 mg m-3. Overall these results, coupled with an excellent data coverage and scarce need of maintenance make the AIRQino or similar devices integrations an interesting tool for future extended sensor networks also in the Arctic environment.
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Affiliation(s)
- Federico Carotenuto
- Institute of BioEconomy, National Research Council of Italy (CNR IBE), 50019 Sesto Fiorentino (FI), Italy; (L.B.); (G.G.); (C.V.); (A.Z.)
| | - Lorenzo Brilli
- Institute of BioEconomy, National Research Council of Italy (CNR IBE), 50019 Sesto Fiorentino (FI), Italy; (L.B.); (G.G.); (C.V.); (A.Z.)
| | - Beniamino Gioli
- Institute of BioEconomy, National Research Council of Italy (CNR IBE), 50019 Sesto Fiorentino (FI), Italy; (L.B.); (G.G.); (C.V.); (A.Z.)
| | - Giovanni Gualtieri
- Institute of BioEconomy, National Research Council of Italy (CNR IBE), 50019 Sesto Fiorentino (FI), Italy; (L.B.); (G.G.); (C.V.); (A.Z.)
| | - Carolina Vagnoli
- Institute of BioEconomy, National Research Council of Italy (CNR IBE), 50019 Sesto Fiorentino (FI), Italy; (L.B.); (G.G.); (C.V.); (A.Z.)
| | - Mauro Mazzola
- Institute of Polar Sciences, National Research Council of Italy (CNR ISP), 40129 Bologna (BO), Italy; (M.M.); (A.P.V.); (V.V.)
| | - Angelo Pietro Viola
- Institute of Polar Sciences, National Research Council of Italy (CNR ISP), 40129 Bologna (BO), Italy; (M.M.); (A.P.V.); (V.V.)
| | - Vito Vitale
- Institute of Polar Sciences, National Research Council of Italy (CNR ISP), 40129 Bologna (BO), Italy; (M.M.); (A.P.V.); (V.V.)
| | - Mirko Severi
- Chemistry Department, University of Florence, 50019 Sesto Fiorentino (FI), Italy; (M.S.); (R.T.)
| | - Rita Traversi
- Chemistry Department, University of Florence, 50019 Sesto Fiorentino (FI), Italy; (M.S.); (R.T.)
| | - Alessandro Zaldei
- Institute of BioEconomy, National Research Council of Italy (CNR IBE), 50019 Sesto Fiorentino (FI), Italy; (L.B.); (G.G.); (C.V.); (A.Z.)
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34
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Liu Z, Kimball JS, Parazoo NC, Ballantyne AP, Wang WJ, Madani N, Pan CG, Watts JD, Reichle RH, Sonnentag O, Marsh P, Hurkuck M, Helbig M, Quinton WL, Zona D, Ueyama M, Kobayashi H, Euskirchen ES. Increased high-latitude photosynthetic carbon gain offset by respiration carbon loss during an anomalous warm winter to spring transition. GLOBAL CHANGE BIOLOGY 2020; 26:682-696. [PMID: 31596019 DOI: 10.1111/gcb.14863] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 07/21/2019] [Indexed: 06/10/2023]
Abstract
Arctic and boreal ecosystems play an important role in the global carbon (C) budget, and whether they act as a future net C sink or source depends on climate and environmental change. Here, we used complementary in situ measurements, model simulations, and satellite observations to investigate the net carbon dioxide (CO2 ) seasonal cycle and its climatic and environmental controls across Alaska and northwestern Canada during the anomalously warm winter to spring conditions of 2015 and 2016 (relative to 2010-2014). In the warm spring, we found that photosynthesis was enhanced more than respiration, leading to greater CO2 uptake. However, photosynthetic enhancement from spring warming was partially offset by greater ecosystem respiration during the preceding anomalously warm winter, resulting in nearly neutral effects on the annual net CO2 balance. Eddy covariance CO2 flux measurements showed that air temperature has a primary influence on net CO2 exchange in winter and spring, while soil moisture has a primary control on net CO2 exchange in the fall. The net CO2 exchange was generally more moisture limited in the boreal region than in the Arctic tundra. Our analysis indicates complex seasonal interactions of underlying C cycle processes in response to changing climate and hydrology that may not manifest in changes in net annual CO2 exchange. Therefore, a better understanding of the seasonal response of C cycle processes may provide important insights for predicting future carbon-climate feedbacks and their consequences on atmospheric CO2 dynamics in the northern high latitudes.
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Affiliation(s)
- Zhihua Liu
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
- Numerical Terradynamic Simulation Group, WA Franke College of Forestry and Conservation, University of Montana, Missoula, MT, USA
| | - John S Kimball
- Numerical Terradynamic Simulation Group, WA Franke College of Forestry and Conservation, University of Montana, Missoula, MT, USA
- Department of Ecosystem and Conservation Sciences, WA Franke College of Forestry and Conservation, University of Montana, Missoula, MT, USA
| | - Nicholas C Parazoo
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Ashley P Ballantyne
- Department of Ecosystem and Conservation Sciences, WA Franke College of Forestry and Conservation, University of Montana, Missoula, MT, USA
| | - Wen J Wang
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
| | - Nima Madani
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Caleb G Pan
- Numerical Terradynamic Simulation Group, WA Franke College of Forestry and Conservation, University of Montana, Missoula, MT, USA
| | | | | | - Oliver Sonnentag
- Département de géographie and Centre d'études nordiques, Université de Montréal, Montreal, QC, Canada
| | - Philip Marsh
- Cold Regions Research Centre, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Miriam Hurkuck
- Département de géographie and Centre d'études nordiques, Université de Montréal, Montreal, QC, Canada
| | - Manuel Helbig
- School of Geography and Earth Sciences, McMaster University, Hamilton, ON, Canada
| | - William L Quinton
- Cold Regions Research Centre, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Donatella Zona
- Global Change Research Group, Department of Biology, San Diego State University, San Diego, CA, USA
| | - Masahito Ueyama
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Japan
| | - Hideki Kobayashi
- Institute of Arctic Climate and Environment Research, Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan
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Natali SM, Watts JD, Rogers BM, Potter S, Ludwig SM, Selbmann AK, Sullivan PF, Abbott BW, Arndt KA, Birch L, Björkman MP, Bloom AA, Celis G, Christensen TR, Christiansen CT, Commane R, Cooper EJ, Crill P, Czimczik C, Davydov S, Du J, Egan JE, Elberling B, Euskirchen ES, Friborg T, Genet H, Göckede M, Goodrich JP, Grogan P, Helbig M, Jafarov EE, Jastrow JD, Kalhori AAM, Kim Y, Kimball J, Kutzbach L, Lara MJ, Larsen KS, Lee BY, Liu Z, Loranty MM, Lund M, Lupascu M, Madani N, Malhotra A, Matamala R, McFarland J, McGuire AD, Michelsen A, Minions C, Oechel WC, Olefeldt D, Parmentier FJW, Pirk N, Poulter B, Quinton W, Rezanezhad F, Risk D, Sachs T, Schaefer K, Schmidt NM, Schuur EA, Semenchuk PR, Shaver G, Sonnentag O, Starr G, Treat CC, Waldrop MP, Wang Y, Welker J, Wille C, Xu X, Zhang Z, Zhuang Q, Zona D. Large loss of CO 2 in winter observed across the northern permafrost region. NATURE CLIMATE CHANGE 2019; 9:852-857. [PMID: 35069807 PMCID: PMC8781060 DOI: 10.1038/s41558-019-0592-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 09/04/2019] [Indexed: 05/18/2023]
Abstract
Recent warming in the Arctic, which has been amplified during the winter1-3, greatly enhances microbial decomposition of soil organic matter and subsequent release of carbon dioxide (CO2)4. However, the amount of CO2 released in winter is highly uncertain and has not been well represented by ecosystem models or by empirically-based estimates5,6. Here we synthesize regional in situ observations of CO2 flux from arctic and boreal soils to assess current and future winter carbon losses from the northern permafrost domain. We estimate a contemporary loss of 1662 Tg C yr-1 from the permafrost region during the winter season (October through April). This loss is greater than the average growing season carbon uptake for this region estimated from process models (-1032 Tg C yr-1). Extending model predictions to warmer conditions in 2100 indicates that winter CO2 emissions will increase 17% under a moderate mitigation scenario-Representative Concentration Pathway (RCP) 4.5-and 41% under business-as-usual emissions scenario-RCP 8.5. Our results provide a new baseline for winter CO2 emissions from northern terrestrial regions and indicate that enhanced soil CO2 loss due to winter warming may offset growing season carbon uptake under future climatic conditions.
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Affiliation(s)
- Susan. M. Natali
- Woods Hole Research Center, Falmouth, MA 02540, USA
- Correspondence to:
| | | | | | | | | | | | - Patrick F. Sullivan
- Environment and Natural Resources Institute, University of Alaska, Anchorage, AK 99508. USA
| | - Benjamin W. Abbott
- Brigham Young University, Department of Plant and Wildlife Sciences, Provo, UT 84602, USA
| | - Kyle A. Arndt
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
| | - Leah Birch
- Woods Hole Research Center, Falmouth, MA 02540, USA
| | - Mats P. Björkman
- Department of Earth Sciences, University of Gothenburg, PO Box 460, SE-405 30 Göteborg, Sweden
| | - A. Anthony Bloom
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Gerardo Celis
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ 86001, USA
| | - Torben R. Christensen
- Department of Bioscience, Arctic Research Centre, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | | | - Roisin Commane
- Dept. of Earth & Environmental Sciences of Lamont-Doherty Earth Observatory at Columbia University, Palisades, NY 10964, USA
| | - Elisabeth J. Cooper
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT. The Arctic University of Norway, N9037 Tromsø, Norway
| | - Patrick Crill
- Dept. of Geological Sciences and Bolin Centre for Climate Research, Stockholm University, Sweden
| | - Claudia Czimczik
- Earth System Science, University of California, Irvine, CA 92697, USA
| | - Sergey Davydov
- Northeast Science Station, Pacific Geographical Institute, Cherskii, Russia
| | - Jinyang Du
- Numerical Terradynamic Simulation Group, W.A. Franke College of Forestry & Conservation, University of Montana, Missoula, MT 59812, USA
| | - Jocelyn E. Egan
- Department of Earth Sciences, Dalhousie University, Halifax, NS, Canada
| | - Bo Elberling
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen, Denmark
| | - Eugenie S. Euskirchen
- University of Alaska Fairbanks, Institute of Arctic Biology, Fairbanks, AK 99775, USA
| | - Thomas Friborg
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark
| | - Hélène Genet
- University of Alaska Fairbanks, Institute of Arctic Biology, Fairbanks, AK 99775, USA
| | | | - Jordan P. Goodrich
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
- Scripps Institution of Oceanography, UCSD, La Jolla, CA 92037, USA
| | - Paul Grogan
- Department of Biology, Queen’s University, Kingston, ON, Canada
| | - Manuel Helbig
- McMaster University, School of Geography and Earth Sciences, Hamilton, ON, L8S 4K1
- Université de Montréal, Département de géographie & Centre d’études nordiques, 520 chemin de la Côte Sainte Catherine, Montréal, QC H2V 2B8
| | - Elchin E. Jafarov
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Julie D. Jastrow
- Environmental Science Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Aram A. M. Kalhori
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
| | - Yongwon Kim
- International Arctic Research Center, University of Alaska Fairbanks, AK 99775, USA
| | - John Kimball
- Numerical Terradynamic Simulation Group, W.A. Franke College of Forestry & Conservation, University of Montana, Missoula, MT 59812, USA
| | - Lars Kutzbach
- Institute of Soil Science, Universät Hamburg, Hamburg, Germany
| | - Mark J. Lara
- Department of Plant Biology, University of Illinois, Urbana, IL 61801, USA
| | - Klaus S. Larsen
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark
| | - Bang-Yong Lee
- Korea Polar Research Institute (KOPRI), Incheon 21990, Republic of Korea)
| | - Zhihua Liu
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
| | | | - Magnus Lund
- Department of Bioscience, Arctic Research Centre, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Massimo Lupascu
- Department of Geography, National University of Singapore, Singapore 117570
| | - Nima Madani
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Avni Malhotra
- Department of Earth System Science, Stanford University, Stanford, CA 94305
| | - Roser Matamala
- Environmental Science Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Jack McFarland
- Geology, Minerals, Energy, and Geophysics Science Center, U.S. Geological Survey, Menlo Park, CA 94025, USA
| | - A. David McGuire
- University of Alaska Fairbanks, Institute of Arctic Biology, Fairbanks, AK 99775, USA
| | | | | | - Walter C. Oechel
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
- University of Exeter, Exeter, UK
| | - David Olefeldt
- University of Alberta, Department of Renewable Resources, Edmonton, Alberta, Canada
| | - Frans-Jan W. Parmentier
- Department of Geosciences, University of Oslo, Oslo, Norway
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Norbert Pirk
- Department of Geosciences, University of Oslo, Oslo, Norway
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Ben Poulter
- NASA GSFC, Biospheric Sciences Lab., Greenbelt, MD 20771, USA
| | | | - Fereidoun Rezanezhad
- Ecohydrology Research Group, Water Institute and Department of Earth & Environmental Sciences, University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada
| | - David Risk
- St. Francis Xavier University, Antigonish, Nova Scotia, Canada
| | - Torsten Sachs
- GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, Germany
| | - Kevin Schaefer
- National Snow and Ice Data Center, Boulder, CO 80309, USA
| | - Niels M. Schmidt
- Arctic Research Centre, Department of Bioscience, Aarhus University, Roskilde, Denmark
| | - Edward A.G. Schuur
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ 86001, USA
| | - Philipp R. Semenchuk
- Division of Conservation Biology, Vegetation Ecology and Landscape Ecology, Department of Botany and Biodiversity Research, Rennweg 14, 1030 Vienna, Austria
| | - Gaius Shaver
- The Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Oliver Sonnentag
- Université de Montréal, Département de géographie & Centre d’études nordiques, 520 chemin de la Côte Sainte Catherine, Montréal, QC H2V 2B8
| | - Gregory Starr
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487, USA
| | - Claire C. Treat
- Department of Environmental and Biological Science, University of Eastern Finland, Finland
| | - Mark P. Waldrop
- Geology, Minerals, Energy, and Geophysics Science Center, U.S. Geological Survey, Menlo Park, CA 94025, USA
| | - Yihui Wang
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
| | - Jeffrey Welker
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA
- Ecology and Genetics Research Unit, University of Oulu, Finland and UArctic
| | - Christian Wille
- GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, Germany
| | - Xiaofeng Xu
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
| | - Zhen Zhang
- Department of Geographical Sciences, University of Maryland, College Park, MD 20742, USA
| | - Qianlai Zhuang
- Department of Earth, Atmospheric and Planetary Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Donatella Zona
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
- University of Sheffield, Sheffield, UK
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Tundra microbial community taxa and traits predict decomposition parameters of stable, old soil organic carbon. ISME JOURNAL 2019; 13:2901-2915. [PMID: 31384013 DOI: 10.1038/s41396-019-0485-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 04/17/2019] [Accepted: 05/09/2019] [Indexed: 01/08/2023]
Abstract
The susceptibility of soil organic carbon (SOC) in tundra to microbial decomposition under warmer climate scenarios potentially threatens a massive positive feedback to climate change, but the underlying mechanisms of stable SOC decomposition remain elusive. Herein, Alaskan tundra soils from three depths (a fibric O horizon with litter and course roots, an O horizon with decomposing litter and roots, and a mineral-organic mix, laying just above the permafrost) were incubated. Resulting respiration data were assimilated into a 3-pool model to derive decomposition kinetic parameters for fast, slow, and passive SOC pools. Bacterial, archaeal, and fungal taxa and microbial functional genes were profiled throughout the 3-year incubation. Correlation analyses and a Random Forest approach revealed associations between model parameters and microbial community profiles, taxa, and traits. There were more associations between the microbial community data and the SOC decomposition parameters of slow and passive SOC pools than those of the fast SOC pool. Also, microbial community profiles were better predictors of model parameters in deeper soils, which had higher mineral contents and relatively greater quantities of old SOC than in surface soils. Overall, our analyses revealed the functional potential of microbial communities to decompose tundra SOC through a suite of specialized genes and taxa. These results portray divergent strategies by which microbial communities access SOC pools across varying depths, lending mechanistic insights into the vulnerability of what is considered stable SOC in tundra regions.
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37
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Zhu D, Ciais P, Krinner G, Maignan F, Jornet Puig A, Hugelius G. Controls of soil organic matter on soil thermal dynamics in the northern high latitudes. Nat Commun 2019; 10:3172. [PMID: 31320647 PMCID: PMC6639258 DOI: 10.1038/s41467-019-11103-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 06/24/2019] [Indexed: 12/02/2022] Open
Abstract
Permafrost warming and potential soil carbon (SOC) release after thawing may amplify climate change, yet model estimates of present-day and future permafrost extent vary widely, partly due to uncertainties in simulated soil temperature. Here, we derive thermal diffusivity, a key parameter in the soil thermal regime, from depth-specific measurements of monthly soil temperature at about 200 sites in the high latitude regions. We find that, among the tested soil properties including SOC, soil texture, bulk density, and soil moisture, SOC is the dominant factor controlling the variability of diffusivity among sites. Analysis of the CMIP5 model outputs reveals that the parameterization of thermal diffusivity drives the differences in simulated present-day permafrost extent among these models. The strong SOC-thermics coupling is crucial for projecting future permafrost dynamics, since the response of soil temperature and permafrost area to a rising air temperature would be impacted by potential changes in SOC. Soils in the northern permafrost region contain large quantities of organic carbon, formed over long time scales under cold climates. Here the authors test a number of soil properties and show that soil organic carbon is the dominant factor controlling thermal diffusivity among 200 sites in high latitude regions.
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Affiliation(s)
- Dan Zhu
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Gif Sur Yvette, 91191, France.
| | - Philippe Ciais
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Gif Sur Yvette, 91191, France
| | - Gerhard Krinner
- CNRS, Univ. Grenoble Alpes, Institut de Géosciences de l'Environnement (IGE), Grenoble, 38000, France
| | - Fabienne Maignan
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Gif Sur Yvette, 91191, France
| | - Albert Jornet Puig
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Gif Sur Yvette, 91191, France
| | - Gustaf Hugelius
- Department of Physical Geography, Stockholm University, Stockholm, 10691, Sweden.,Bolin Centre for Climate Research, Stockholm University, Stockholm, 10691, Sweden
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Zhang H, Yao Z, Ma L, Zheng X, Wang R, Wang K, Liu C, Zhang W, Zhu B, Tang X, Hu Z, Han S. Annual methane emissions from degraded alpine wetlands in the eastern Tibetan Plateau. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 657:1323-1333. [PMID: 30677899 DOI: 10.1016/j.scitotenv.2018.11.443] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 11/29/2018] [Accepted: 11/29/2018] [Indexed: 06/09/2023]
Abstract
Grazing-oriented drainage of alpine/boreal wetlands has been broadly implemented to meet the increasing demand for animal products. However, the annual methane (CH4) emissions from alpine fens degraded due to drainage for grazing have not been well characterized due to a lack of year-round observations. In this study, the year-round CH4 fluxes from a degraded alpine fen that is typical in the Tibetan Plateau (TP) were measured. The temperature sensitivity of the CH4 emissions during the nongrowing season (NGS) was different between the microsites with and without CH4 uptake during the growing season (GS), showing apparent activation energy of 59-61 vs. 22-43 kJ mol-1 (or variation folds induced by the 10-degree change (i.e., Q10): 2.61-2.74 vs. 1.38-1.91). The CH4 emissions amounted to 0.2-63.3 kg C ha-1 yr-1 (with -0.8 to 41.4 kg C ha-1 and 0.9 to 21.9 kg C ha-1 in the GS and NGS, respectively), which were significantly (P < 0.05) related to the distances to the drainage ditch or water tables across the six microsites. As a key factor, the water table determined the role of the CH4 emissions during freezing/thawing. For cool/cold/alpine wetlands with no CH4 uptake in the GS, a mean factor of 1.52 (within a range of 1.00-2.44 at the 95% confidence interval), corresponding to an NGS contribution of 34% (ranging from 0 to 59%), was recommended to upscale the GS emissions to annual totals. Degradation of the native peat marshes in the Zoige region (originally the largest area of alpine wetlands) due to intentional drainage has greatly reduced the quantities of CH4 emissions. Additional studies are still needed to minimize the large uncertainties in CH4 emissions estimates for the changes in alpine wetlands in this region and for the entire TP.
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Affiliation(s)
- Han Zhang
- Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, College of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044, China; State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Zhisheng Yao
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Lei Ma
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xunhua Zheng
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Science, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Rui Wang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Kai Wang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Chunyan Liu
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Wei Zhang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Bo Zhu
- Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China
| | - Xiangyu Tang
- Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China
| | - Zhenghua Hu
- Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, College of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Shenghui Han
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
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Sistla SA, Schaeffer S, Schimel JP. Plant community regulates decomposer response to freezing more strongly than the rate or extent of the freezing regime. Ecosphere 2019. [DOI: 10.1002/ecs2.2608] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Seeta A. Sistla
- School of Natural Science Hampshire College Amherst Massachusetts 01002 USA
- Department of Ecology, Evolution and Marine Biology and The Environmental Studies Program University of California Santa Barbara Santa Barbara California 93106 USA
| | - Sean Schaeffer
- Department of Ecology, Evolution and Marine Biology and The Environmental Studies Program University of California Santa Barbara Santa Barbara California 93106 USA
- Institute of Agriculture University of Tennessee Knoxville Tennessee 37996 USA
| | - Joshua P. Schimel
- Department of Ecology, Evolution and Marine Biology and The Environmental Studies Program University of California Santa Barbara Santa Barbara California 93106 USA
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Arora B, Wainwright HM, Dwivedi D, Vaughn LJS, Curtis JB, Torn MS, Dafflon B, Hubbard SS. Evaluating temporal controls on greenhouse gas (GHG) fluxes in an Arctic tundra environment: An entropy-based approach. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 649:284-299. [PMID: 30173035 DOI: 10.1016/j.scitotenv.2018.08.251] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 07/23/2018] [Accepted: 08/19/2018] [Indexed: 06/08/2023]
Abstract
There is significant spatial and temporal variability associated with greenhouse gas (GHG) fluxes in high-latitude Arctic tundra environments. The objectives of this study are to investigate temporal variability in CO2 and CH4 fluxes at Barrow, AK and to determine the factors causing this variability using a novel entropy-based classification scheme. In particular, we analyzed which geomorphic, soil, vegetation and climatic properties most explained the variability in GHG fluxes (opaque chamber measurements) during the growing season over three successive years. Results indicate that multi-year variability in CO2 fluxes was primarily associated with soil temperature variability as well as vegetation dynamics during the early and late growing season. Temporal variability in CH4 fluxes was primarily associated with changes in vegetation during the growing season and its interactions with primary controls like seasonal thaw. Polygonal ground features, which are common to Arctic regions, also demonstrated significant multi-year variability in GHG fluxes. Our results can be used to prioritize field sampling strategies, with an emphasis on measurements collected at locations and times that explain the most variability in GHG fluxes. For example, we found that sampling primary environmental controls at the centers of high centered polygons in the month of September (when freeze-back period begins) can provide significant constraints on GHG flux variability - a requirement for accurately predicting future changes to GHG fluxes. Overall, entropy results document the impact of changing environmental conditions (e.g., warming, growing season length) on GHG fluxes, thus providing clues concerning the manner in which ecosystem properties may be shifted regionally in a future climate.
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Affiliation(s)
- Bhavna Arora
- Lawrence Berkeley National Laboratory, Berkeley, United States of America.
| | | | - Dipankar Dwivedi
- Lawrence Berkeley National Laboratory, Berkeley, United States of America
| | - Lydia J S Vaughn
- Lawrence Berkeley National Laboratory, Berkeley, United States of America
| | - John B Curtis
- University of Colorado, Boulder, United States of America
| | - Margaret S Torn
- Lawrence Berkeley National Laboratory, Berkeley, United States of America
| | - Baptiste Dafflon
- Lawrence Berkeley National Laboratory, Berkeley, United States of America
| | - Susan S Hubbard
- Lawrence Berkeley National Laboratory, Berkeley, United States of America
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41
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Treharne R, Bjerke JW, Tømmervik H, Stendardi L, Phoenix GK. Arctic browning: Impacts of extreme climatic events on heathland ecosystem CO 2 fluxes. GLOBAL CHANGE BIOLOGY 2019; 25:489-503. [PMID: 30474169 PMCID: PMC7379734 DOI: 10.1111/gcb.14500] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 10/05/2018] [Accepted: 10/15/2018] [Indexed: 05/22/2023]
Abstract
Extreme climatic events are among the drivers of recent declines in plant biomass and productivity observed across Arctic ecosystems, known as "Arctic browning." These events can cause landscape-scale vegetation damage and so are likely to have major impacts on ecosystem CO2 balance. However, there is little understanding of the impacts on CO2 fluxes, especially across the growing season. Furthermore, while widespread shoot mortality is commonly observed with browning events, recent observations show that shoot stress responses are also common, and manifest as high levels of persistent anthocyanin pigmentation. Whether or how this response impacts ecosystem CO2 fluxes is not known. To address these research needs, a growing season assessment of browning impacts following frost drought and extreme winter warming (both extreme climatic events) on the key ecosystem CO2 fluxes Net Ecosystem Exchange (NEE), Gross Primary Productivity (GPP), ecosystem respiration (Reco ) and soil respiration (Rsoil ) was carried out in widespread sub-Arctic dwarf shrub heathland, incorporating both mortality and stress responses. Browning (mortality and stress responses combined) caused considerable site-level reductions in GPP and NEE (of up to 44%), with greatest impacts occurring at early and late season. Furthermore, impacts on CO2 fluxes associated with stress often equalled or exceeded those resulting from vegetation mortality. This demonstrates that extreme events can have major impacts on ecosystem CO2 balance, considerably reducing the carbon sink capacity of the ecosystem, even where vegetation is not killed. Structural Equation Modelling and additional measurements, including decomposition rates and leaf respiration, provided further insight into mechanisms underlying impacts of mortality and stress on CO2 fluxes. The scale of reductions in ecosystem CO2 uptake highlights the need for a process-based understanding of Arctic browning in order to predict how vegetation and CO2 balance will respond to continuing climate change.
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Affiliation(s)
- Rachael Treharne
- Department of Animal and Plant SciencesThe University of SheffieldSheffieldUK
| | - Jarle W. Bjerke
- Norwegian Institute for Nature ResearchHigh North Research Centre for Climate and the EnvironmentTromsøNorway
| | - Hans Tømmervik
- Norwegian Institute for Nature ResearchHigh North Research Centre for Climate and the EnvironmentTromsøNorway
| | | | - Gareth K. Phoenix
- Department of Animal and Plant SciencesThe University of SheffieldSheffieldUK
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Schuur EA, Mack MC. Ecological Response to Permafrost Thaw and Consequences for Local and Global Ecosystem Services. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2018. [DOI: 10.1146/annurev-ecolsys-121415-032349] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The Arctic may seem remote, but the unprecedented environmental changes occurring there have important consequences for global society. Of all Arctic system components, changes in permafrost (perennially frozen ground) are one of the least documented. Permafrost is degrading as a result of climate warming, and evidence is mounting that changing permafrost will have significant impacts within and outside the region. This review asks: What are key structural and functional properties of ecosystems that interact with changing permafrost, and how do these ecosystem changes affect local and global society? Here, we look beyond the classic definition of permafrost to include a broadened focus on the composition of frozen ground, including the ice and the soil organic carbon content, and how it is changing. This ecological perspective of permafrost serves to identify areas of both vulnerability and resilience as climate, ecological disturbance regimes, and the human footprint all continue to change in this sensitive and critical region of Earth.
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Affiliation(s)
| | - Michelle C. Mack
- Center for Ecosystem Science and Society, and Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona 86011, USA
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Lyu Z, Genet H, He Y, Zhuang Q, McGuire AD, Bennett A, Breen A, Clein J, Euskirchen ES, Johnson K, Kurkowski T, Pastick NJ, Rupp TS, Wylie BK, Zhu Z. The role of environmental driving factors in historical and projected carbon dynamics of wetland ecosystems in Alaska. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2018; 28:1377-1395. [PMID: 29808543 DOI: 10.1002/eap.1755] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 04/05/2018] [Accepted: 04/13/2018] [Indexed: 06/08/2023]
Abstract
Wetlands are critical terrestrial ecosystems in Alaska, covering ~177,000 km2 , an area greater than all the wetlands in the remainder of the United States. To assess the relative influence of changing climate, atmospheric carbon dioxide (CO2 ) concentration, and fire regime on carbon balance in wetland ecosystems of Alaska, a modeling framework that incorporates a fire disturbance model and two biogeochemical models was used. Spatially explicit simulations were conducted at 1-km resolution for the historical period (1950-2009) and future projection period (2010-2099). Simulations estimated that wetland ecosystems of Alaska lost 175 Tg carbon (C) in the historical period. Ecosystem C storage in 2009 was 5,556 Tg, with 89% of the C stored in soils. The estimated loss of C as CO2 and biogenic methane (CH4 ) emissions resulted in wetlands of Alaska increasing the greenhouse gas forcing of climate warming. Simulations for the projection period were conducted for six climate change scenarios constructed from two climate models forced under three CO2 emission scenarios. Ecosystem C storage averaged among climate scenarios increased 3.94 Tg C/yr by 2099, with variability among the simulations ranging from 2.02 to 4.42 Tg C/yr. These increases were driven primarily by increases in net primary production (NPP) that were greater than losses from increased decomposition and fire. The NPP increase was driven by CO2 fertilization (~5% per 100 parts per million by volume increase) and by increases in air temperature (~1% per °C increase). Increases in air temperature were estimated to be the primary cause for a projected 47.7% mean increase in biogenic CH4 emissions among the simulations (~15% per °C increase). Ecosystem CO2 sequestration offset the increase in CH4 emissions during the 21st century to decrease the greenhouse gas forcing of climate warming. However, beyond 2100, we expect that this forcing will ultimately increase as wetland ecosystems transition from being a sink to a source of atmospheric CO2 because of (1) decreasing sensitivity of NPP to increasing atmospheric CO2 , (2) increasing availability of soil C for decomposition as permafrost thaws, and (3) continued positive sensitivity of biogenic CH4 emissions to increases in soil temperature.
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Affiliation(s)
- Zhou Lyu
- Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana, 47907, USA
| | - Hélène Genet
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Yujie He
- Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana, 47907, USA
| | - Qianlai Zhuang
- Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana, 47907, USA
| | - A David McGuire
- U.S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Alec Bennett
- Scenarios Network for Alaska and Arctic Planning, International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Amy Breen
- Scenarios Network for Alaska and Arctic Planning, International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Joy Clein
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Eugénie S Euskirchen
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Kristofer Johnson
- U.S. Department of Agriculture, Forest Service, Northern Research Station, Newtown Square, Pennsylvania, 19073, USA
| | - Tom Kurkowski
- Scenarios Network for Alaska and Arctic Planning, International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Neal J Pastick
- Department of Forest Resources, University of Minnesota, St. Paul, Minnesota, 55108, USA
- Stinger Ghaffarian Technologies Inc., contractor to the U.S. Geological Survey, Sioux Falls, South Dakota, 57198, USA
| | - T Scott Rupp
- Scenarios Network for Alaska and Arctic Planning, International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Bruce K Wylie
- U.S. Geological Survey, The Earth Resources Observation Systems Center, Sioux Falls, South Dakota, 57198, USA
| | - Zhiliang Zhu
- U.S. Geological Survey, Reston, Virginia, 12201, USA
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21st-century modeled permafrost carbon emissions accelerated by abrupt thaw beneath lakes. Nat Commun 2018; 9:3262. [PMID: 30111815 PMCID: PMC6093858 DOI: 10.1038/s41467-018-05738-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 07/17/2018] [Indexed: 12/01/2022] Open
Abstract
Permafrost carbon feedback (PCF) modeling has focused on gradual thaw of near-surface permafrost leading to enhanced carbon dioxide and methane emissions that accelerate global climate warming. These state-of-the-art land models have yet to incorporate deeper, abrupt thaw in the PCF. Here we use model data, supported by field observations, radiocarbon dating, and remote sensing, to show that methane and carbon dioxide emissions from abrupt thaw beneath thermokarst lakes will more than double radiative forcing from circumpolar permafrost-soil carbon fluxes this century. Abrupt thaw lake emissions are similar under moderate and high representative concentration pathways (RCP4.5 and RCP8.5), but their relative contribution to the PCF is much larger under the moderate warming scenario. Abrupt thaw accelerates mobilization of deeply frozen, ancient carbon, increasing 14C-depleted permafrost soil carbon emissions by ~125–190% compared to gradual thaw alone. These findings demonstrate the need to incorporate abrupt thaw processes in earth system models for more comprehensive projection of the PCF this century. Permafrost carbon feedback modeling has focused on gradual thaw of near-surface permafrost leading to greenhouse gas emissions that accelerate climate change. Here the authors show that deeper, abrupt thaw beneath lakes will more than double radiative forcing from permafrost-soil carbon fluxes this century.
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45
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Parazoo NC, Arneth A, Pugh TAM, Smith B, Steiner N, Luus K, Commane R, Benmergui J, Stofferahn E, Liu J, Rödenbeck C, Kawa R, Euskirchen E, Zona D, Arndt K, Oechel W, Miller C. Spring photosynthetic onset and net CO 2 uptake in Alaska triggered by landscape thawing. GLOBAL CHANGE BIOLOGY 2018; 24:3416-3435. [PMID: 29688596 DOI: 10.1111/gcb.14283] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 03/12/2018] [Accepted: 04/10/2018] [Indexed: 06/08/2023]
Abstract
The springtime transition to regional-scale onset of photosynthesis and net ecosystem carbon uptake in boreal and tundra ecosystems are linked to the soil freeze-thaw state. We present evidence from diagnostic and inversion models constrained by satellite fluorescence and airborne CO2 from 2012 to 2014 indicating the timing and magnitude of spring carbon uptake in Alaska correlates with landscape thaw and ecoregion. Landscape thaw in boreal forests typically occurs in late April (DOY 111 ± 7) with a 29 ± 6 day lag until photosynthetic onset. North Slope tundra thaws 3 weeks later (DOY 133 ± 5) but experiences only a 20 ± 5 day lag until photosynthetic onset. These time lag differences reflect efficient cold season adaptation in tundra shrub and the longer dehardening period for boreal evergreens. Despite the short transition from thaw to photosynthetic onset in tundra, synchrony of tundra respiration with snow melt and landscape thaw delays the transition from net carbon loss (at photosynthetic onset) to net uptake by 13 ± 7 days, thus reducing the tundra net carbon uptake period. Two global CO2 inversions using a CASA-GFED model prior estimate earlier northern high latitude net carbon uptake compared to our regional inversion, which we attribute to (i) early photosynthetic-onset model prior bias, (ii) inverse method (scaling factor + optimization window), and (iii) sparsity of available Alaskan CO2 observations. Another global inversion with zero prior estimates the same timing for net carbon uptake as the regional model but smaller seasonal amplitude. The analysis of Alaskan eddy covariance observations confirms regional scale findings for tundra, but indicates that photosynthesis and net carbon uptake occur up to 1 month earlier in evergreens than captured by models or CO2 inversions, with better correlation to above-freezing air temperature than date of primary thaw. Further collection and analysis of boreal evergreen species over multiple years and at additional subarctic flux towers are critically needed.
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Affiliation(s)
- Nicholas C Parazoo
- California Institute of Technology, Jet Propulsion Laboratory, Pasadena, California
| | - Almut Arneth
- Institute of Meteorology and Climate Research (IMK-IFU), Karlsruhe Institute of Technology, Garmisch-Pertenkirchen, Germany
| | - Thomas A M Pugh
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
- Birmingham Institute of Forest Research, University of Birmingham, Birmingham, UK
| | - Ben Smith
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Nicholas Steiner
- Department of Earth and Atmospheric Sciences, The City College of New York, New York, New York
| | | | - Roisin Commane
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts
| | - Josh Benmergui
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts
| | | | - Junjie Liu
- California Institute of Technology, Jet Propulsion Laboratory, Pasadena, California
| | | | - Randy Kawa
- NASA Goddard Space Flight Center, Greenbelt, Maryland
| | - Eugenie Euskirchen
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska
| | - Donatella Zona
- Biology Department, San Diego State University, San Diego, California
| | - Kyle Arndt
- Biology Department, San Diego State University, San Diego, California
| | - Walt Oechel
- Biology Department, San Diego State University, San Diego, California
| | - Charles Miller
- California Institute of Technology, Jet Propulsion Laboratory, Pasadena, California
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46
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Treat CC, Bloom AA, Marushchak ME. Nongrowing season methane emissions-a significant component of annual emissions across northern ecosystems. GLOBAL CHANGE BIOLOGY 2018; 24:3331-3343. [PMID: 29569301 DOI: 10.1111/gcb.14137] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 02/11/2018] [Indexed: 06/08/2023]
Abstract
Wetlands are the single largest natural source of atmospheric methane (CH4 ), a greenhouse gas, and occur extensively in the northern hemisphere. Large discrepancies remain between "bottom-up" and "top-down" estimates of northern CH4 emissions. To explore whether these discrepancies are due to poor representation of nongrowing season CH4 emissions, we synthesized nongrowing season and annual CH4 flux measurements from temperate, boreal, and tundra wetlands and uplands. Median nongrowing season wetland emissions ranged from 0.9 g/m2 in bogs to 5.2 g/m2 in marshes and were dependent on moisture, vegetation, and permafrost. Annual wetland emissions ranged from 0.9 g m-2 year-1 in tundra bogs to 78 g m-2 year-1 in temperate marshes. Uplands varied from CH4 sinks to CH4 sources with a median annual flux of 0.0 ± 0.2 g m-2 year-1 . The measured fraction of annual CH4 emissions during the nongrowing season (observed: 13% to 47%) was significantly larger than that was predicted by two process-based model ensembles, especially between 40° and 60°N (modeled: 4% to 17%). Constraining the model ensembles with the measured nongrowing fraction increased total nongrowing season and annual CH4 emissions. Using this constraint, the modeled nongrowing season wetland CH4 flux from >40° north was 6.1 ± 1.5 Tg/year, three times greater than the nongrowing season emissions of the unconstrained model ensemble. The annual wetland CH4 flux was 37 ± 7 Tg/year from the data-constrained model ensemble, 25% larger than the unconstrained ensemble. Considering nongrowing season processes is critical for accurately estimating CH4 emissions from high-latitude ecosystems, and necessary for constraining the role of wetland emissions in a warming climate.
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Affiliation(s)
- Claire C Treat
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
| | - A Anthony Bloom
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Maija E Marushchak
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
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47
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Christiansen CT, Lafreniére MJ, Henry GHR, Grogan P. Long-term deepened snow promotes tundra evergreen shrub growth and summertime ecosystem net CO 2 gain but reduces soil carbon and nutrient pools. GLOBAL CHANGE BIOLOGY 2018; 24:3508-3525. [PMID: 29411950 DOI: 10.1111/gcb.14084] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Accepted: 01/16/2018] [Indexed: 06/08/2023]
Abstract
Arctic climate warming will be primarily during winter, resulting in increased snowfall in many regions. Previous tundra research on the impacts of deepened snow has generally been of short duration. Here, we report relatively long-term (7-9 years) effects of experimentally deepened snow on plant community structure, net ecosystem CO2 exchange (NEE), and soil biogeochemistry in Canadian Low Arctic mesic shrub tundra. The snowfence treatment enhanced snow depth from 0.3 to ~1 m, increasing winter soil temperatures by ~3°C, but with no effect on summer soil temperature, moisture, or thaw depth. Nevertheless, shoot biomass of the evergreen shrub Rhododendron subarcticum was near-doubled by the snowfences, leading to a 52% increase in aboveground vascular plant biomass. Additionally, summertime NEE rates, measured in collars containing similar plant biomass across treatments, were consistently reduced ~30% in the snowfenced plots due to decreased ecosystem respiration rather than increased gross photosynthesis. Phosphate in the organic soil layer (0-10 cm depth) and nitrate in the mineral soil layer (15-25 cm depth) were substantially reduced within the snowfences (47-70 and 43%-73% reductions, respectively, across sampling times). Finally, the snowfences tended (p = .08) to reduce mineral soil layer C% by 40%, but with considerable within- and among plot variation due to cryoturbation across the landscape. These results indicate that enhanced snow accumulation is likely to further increase dominance of R. subarcticum in its favored locations, and reduce summertime respiration and soil biogeochemical pools. Since evergreens are relatively slow growing and of low stature, their increased dominance may constrain vegetation-related feedbacks to climate change. We found no evidence that deepened snow promoted deciduous shrub growth in mesic tundra, and conclude that the relatively strong R. subarcticum response to snow accumulation may explain the extensive spatial variability in observed circumpolar patterns of evergreen and deciduous shrub growth over the past 30 years.
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Affiliation(s)
- Casper T Christiansen
- Department of Biology, Queen's University, Kingston, ON, Canada
- Uni Research Climate, Bjerknes Centre for Climate Research, Bergen, Norway
| | | | - Gregory H R Henry
- Department of Geography, University of British Columbia, Vancouver, BC, Canada
| | - Paul Grogan
- Department of Biology, Queen's University, Kingston, ON, Canada
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48
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Zhang Z, Zimmermann NE, Calle L, Hurtt G, Chatterjee A, Poulter B. Enhanced response of global wetland methane emissions to the 2015-2016 El Niño-Southern Oscillation event. ENVIRONMENTAL RESEARCH LETTERS : ERL [WEB SITE] 2018; 13:074009. [PMID: 32788924 PMCID: PMC7418631 DOI: 10.1088/1748-9326/aac939] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Wetlands are thought to be the major contributor to interannual variability in the growth rate of atmospheric methane (CH4) with anomalies driven by the influence of the El Niño-Southern Oscillation (ENSO). Yet it remains unclear whether (i) the increase in total global CH4 emissions during El Niño versus La Niña events is from wetlands and (ii) how large the contribution of wetland CH4 emissions is to the interannual variability of atmospheric CH4. We used a terrestrial ecosystem model that includes permafrost and wetland dynamics to estimate CH4 emissions, forced by three separate meteorological reanalyses and one gridded observational climate dataset, to simulate the spatio-temporal dynamics of wetland CH4 emissions from 1980-2016. The simulations show that while wetland CH4 responds with negative annual anomalies during the El Niño events, the instantaneous growth rate of wetland CH4 emissions exhibits complex phase dynamics. We find that wetland CH4 instantaneous growth rates were declined at the onset of the 2015-2016 El Niño event but then increased to a record-high at later stages of the El Niño event (January through May 2016). We also find evidence for a step increase of CH4 emissions by 7.8±1.6 Tg CH4 yr-1 during 2007-2014 compared to the average of 2000-2006 from simulations using meteorological reanalyses, which is equivalent to a ~3.5 ppb yr-1 rise in CH4 concentrations. The step increase is mainly caused by the expansion of wetland area in the tropics (30°S-30°N) due to an enhancement of tropical precipitation as indicated by the suite of the meteorological reanalyses. Our study highlights the role of wetlands, and the complex temporal phasing with ENSO, in driving the variability and trends of atmospheric CH4 concentrations. In addition, the need to account for uncertainty in meteorological forcings is highlighted in addressing the interannual variability and decadal-scale trends of wetland CH4 fluxes.
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Affiliation(s)
- Zhen Zhang
- Department of Geographical Sciences, University of Maryland, College Park, MD 20740, USA
- Dynamic Macroecology, Swiss Federal Research Institute WSL, Zürcherstrasse 111, Birmensdorf 8903, Switzerland
| | - Niklaus E Zimmermann
- Dynamic Macroecology, Swiss Federal Research Institute WSL, Zürcherstrasse 111, Birmensdorf 8903, Switzerland
- Department of Environmental System Science, Swiss Federal Institute of Technology ETH, Zürich 8092, Switzerland
| | - Leonardo Calle
- Department of Ecology, Montana State University, Bozeman, MT 59717, USA
| | - George Hurtt
- Department of Geographical Sciences, University of Maryland, College Park, MD 20740, USA
| | - Abhishek Chatterjee
- Biospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
- Universities Space Research Association, Columbia, MD 21046, USA
| | - Benjamin Poulter
- Biospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
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49
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Ren J, Song C, Hou A, Song Y, Zhu X, Cagle GA. Shifts in soil bacterial and archaeal communities during freeze-thaw cycles in a seasonal frozen marsh, Northeast China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 625:782-791. [PMID: 29306166 DOI: 10.1016/j.scitotenv.2017.12.309] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 12/19/2017] [Accepted: 12/27/2017] [Indexed: 06/07/2023]
Abstract
Diurnal freeze-thaw cycles (FTCs) occur in the spring and autumn in boreal wetlands as soil temperatures rise above freezing during the day and fall below freezing at night. A surge in methane emissions from these systems is frequently documented during spring FTCs, accounting for a large portion of annual emissions. In boreal wetlands, methane is produced as a result of syntrophic microbial processes, mediated by a consortium of fermenting bacteria and methanogenic archaea. Further research is needed to determine whether FTCs enhance microbial metabolism related to methane production through the cryogenic decomposition of soil organic matter. Previous studies observed large methane emissions during the spring thawed period in the Sanjiang seasonal frozen marsh of Northeast China. To investigate how FTCs impact the soil microbial community and methanogen abundance and activity, we collected soil cores from the Sanjiang marsh during the FTCs of autumn 2014 and spring 2015. Methanogens were investigated based on expression level of the methyl coenzyme reductase (mcrA) gene, and soil bacterial and archaeal community structures were assessed by 16S rRNA gene sequencing. The results show that a decrease in bacteria and methanogens followed autumns FTCs, whereas an increase in bacteria and methanogens was observed following spring FTCs. The bacterial community structure, including Firmicutes and certain Deltaproteobacteria, was changed following autumn FTCs. Temperature and substrate were the primary factors regulating the abundance and composition of the microbial communities during autumn FTCs, whereas no factors significantly contributing to spring FTCs were identified. Acetoclastic methanogens from order Methanosarcinales were the dominant group at the beginning and end of both the autumn and spring FTCs. Active methanogens were significantly more abundant during the diurnal thawed period, indicating that the increasing number of FTCs predicted to occur with global climate change could potentially promote CH4 emissions in seasonal frozen marshes.
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Affiliation(s)
- Jiusheng Ren
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Changchun Song
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, PR China.
| | - Aixin Hou
- Department of Environmental Sciences, College of the Coast and Environment, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Yanyu Song
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, PR China
| | - Xiaoyan Zhu
- Key Laboratory of Songliao Aquatic Environment, Ministry of Education, Jilin Jianzhu University, Xincheng Street, District 5088, Changchun 130118, PR China
| | - Grace Ann Cagle
- Department of Environmental Sciences, College of the Coast and Environment, Louisiana State University, Baton Rouge, LA 70803, USA
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50
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Yang G, Peng Y, Olefeldt D, Chen Y, Wang G, Li F, Zhang D, Wang J, Yu J, Liu L, Qin S, Sun T, Yang Y. Changes in Methane Flux along a Permafrost Thaw Sequence on the Tibetan Plateau. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:1244-1252. [PMID: 29276825 DOI: 10.1021/acs.est.7b04979] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Permafrost thaw alters the physical and environmental conditions of soil and may thus cause a positive feedback to climate warming through increased methane emissions. However, the current knowledge of methane emissions following thermokarst development is primarily based on expanding lakes and wetlands, with upland thermokarst being studied less often. In this study, we monitored the methane emissions during the peak growing seasons of two consecutive years along a thaw sequence within a thermo-erosion gully in a Tibetan swamp meadow. Both years had consistent results, with the early and midthaw stages (3 to 12 years since thaw) exhibiting low methane emissions that were similar to those in the undisturbed meadow, while the emissions from the late thaw stage (20 years since thaw) were 3.5 times higher. Our results also showed that the soil water-filled pore space, rather than the soil moisture per se, in combination with the sand content, were the main factors that caused increased methane emissions. These findings differ from the traditional view that upland thermokarst could reduce methane emissions owing to the improvement of drainage conditions, suggesting that upland thermokarst development does not always result in a decrease in methane emissions.
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Affiliation(s)
- Guibiao Yang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences , Beijing 100093, China
- University of Chinese Academy of Sciences , Beijing 100049, China
| | - Yunfeng Peng
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences , Beijing 100093, China
| | - David Olefeldt
- Department of Renewable Resources, University of Alberta , Edmonton, Alberta Canada , T6G 2H1
| | - Yongliang Chen
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences , Beijing 100093, China
| | - Guanqin Wang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences , Beijing 100093, China
- University of Chinese Academy of Sciences , Beijing 100049, China
| | - Fei Li
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences , Beijing 100093, China
- University of Chinese Academy of Sciences , Beijing 100049, China
| | - Dianye Zhang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences , Beijing 100093, China
- University of Chinese Academy of Sciences , Beijing 100049, China
| | - Jun Wang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences , Beijing 100093, China
- University of Chinese Academy of Sciences , Beijing 100049, China
| | - Jianchun Yu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences , Beijing 100093, China
- University of Chinese Academy of Sciences , Beijing 100049, China
| | - Li Liu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences , Beijing 100093, China
- University of Chinese Academy of Sciences , Beijing 100049, China
| | - Shuqi Qin
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences , Beijing 100093, China
- University of Chinese Academy of Sciences , Beijing 100049, China
| | - Tianyang Sun
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences , Beijing 100093, China
- University of Chinese Academy of Sciences , Beijing 100049, China
| | - Yuanhe Yang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences , Beijing 100093, China
- University of Chinese Academy of Sciences , Beijing 100049, China
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