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Guo Y, Liu S, Qiu L, Zhang C, Shan W. Spatial stratified heterogeneity analysis of field scale permafrost in Northeast China based on optimal parameters-based geographical detector. PLoS One 2024; 19:e0297029. [PMID: 38363764 PMCID: PMC10871524 DOI: 10.1371/journal.pone.0297029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 12/25/2023] [Indexed: 02/18/2024] Open
Abstract
Affected by global warming, the permafrost in Northeast China (NEC) has been continuously degrading in recent years. Many researchers have focused on the spatial and temporal distribution characteristics of permafrost in NEC, however, few studies have delved into the field scale. In this study, based on the Optimal Parameters-based Geographical Detector (OPGD) model and Receiver Operating Characteristic (ROC) test, the spatial stratified heterogeneity of permafrost distribution and the indicating performance of environmental variables on permafrost in NEC at the field scale were analyzed. Permafrost spatial distribution data were obtained from the Engineering Geological Investigation Reports (EGIR) of six highways located in NEC and a total of 19 environmental variables related to heat transfer, vegetation, soil, topography, moisture, and ecology were selected. The H-factors (variables with the highest contribution in factor detector results and interaction detector results): slope position (γ), surface frost number (SFN), elevation (DEM), topographic diversity (TD), and annual snow cover days (ASCD) were found to be the major contributors to the distribution of permafrost at the field scale. Among them, γ has the highest contribution and is a special explanatory variable for permafrost. In most cases, interaction can improve the impact of variables, especially the interaction between H-factors. The risk of permafrost decreases with the increase of TD, RN, and SBD, and increases with the increase of SFN. The performance of SFN to indicate permafrost distribution was found to be the best among all variables (AUC = 0.7063). There is spatial heterogeneity in the distribution of permafrost on highways in different spatial locations. This study summarized the numerical and spatial location between permafrost and different environmental variables at the field scale, and many results were found to be informative for environmental studies and engineering construction in NEC.
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Affiliation(s)
- Ying Guo
- Institute of Cold Regions Science and Engineering, Northeast Forestry University, Harbin, China
- Ministry of Education Observation and Research Station of Permafrost Geo-Environment System in Northeast China, Harbin, China
- Collaborative Innovation Centre for Permafrost Environment and Road Construction and Maintenance in Northeast China, Harbin, China
| | - Shuai Liu
- Institute of Cold Regions Science and Engineering, Northeast Forestry University, Harbin, China
| | - Lisha Qiu
- Institute of Cold Regions Science and Engineering, Northeast Forestry University, Harbin, China
| | - Chengcheng Zhang
- Institute of Cold Regions Science and Engineering, Northeast Forestry University, Harbin, China
- Ministry of Education Observation and Research Station of Permafrost Geo-Environment System in Northeast China, Harbin, China
- Collaborative Innovation Centre for Permafrost Environment and Road Construction and Maintenance in Northeast China, Harbin, China
| | - Wei Shan
- Institute of Cold Regions Science and Engineering, Northeast Forestry University, Harbin, China
- Ministry of Education Observation and Research Station of Permafrost Geo-Environment System in Northeast China, Harbin, China
- Collaborative Innovation Centre for Permafrost Environment and Road Construction and Maintenance in Northeast China, Harbin, China
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2
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Zhao H, Yi P, Pan X, Wan C. The role of root zone soil moisture return on vegetation green-up: A comparison of two degrading permafrost sites. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 905:167049. [PMID: 37709095 DOI: 10.1016/j.scitotenv.2023.167049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 08/23/2023] [Accepted: 09/11/2023] [Indexed: 09/16/2023]
Abstract
The effects of permafrost degradation on ecological changes have attracted more and more attention, but the underlying interactive mechanisms are still not well understood. From a unique angle of view, this study focuses on the linkage between the freezing-induced root zone soil moisture return (SMR) and vegetation green-up along with climate warming and permafrost degradation. Using 7-year soil-weather monitoring data in the high-altitude and high-latitude permafrost regions, we investigated the changes of root zone SMR in two degrading permafrost sites. Results demonstrate that, as one important water source for vegetation green-up, the ratio of root zone SMR to the soil moisture storage after final thawed, Rsmr, could reach 22.8 % and 10.5 % at the two sites, respectively. In contrast to the negligible change at the high-latitude permafrost site, a rapid increase rate of 7.7 % per decade in Rsmr was found at the high-altitude permafrost site over the monitoring period of 2012-2018. Generally, vegetation green-up definitely benefited from the enrichment of soil moisture storage, but their sensitivities to climate warming and permafrost degradation were different at the two sites. The increase of Rsmr effectively buffered the shrinking trend of soil water availability of the root zone both over the pre-freezing and the green-up period at the high-altitude permafrost site. The changing role of root zone SMR might be threatened during the vegetation green-up in the longer future. Whereas, there would be no water shortage risk for the foreseeable future at the high-latitude permafrost site. Overall, this study emphasized the importance of SMR in enhancing soil water availability for vegetation green-up under the background of quick climate warming and permafrost degradation.
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Affiliation(s)
- Hanrui Zhao
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China; College of Hydrology and Water Resources, Hohai University, Nanjing 210098, China
| | - Peng Yi
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China; College of Hydrology and Water Resources, Hohai University, Nanjing 210098, China
| | - Xicai Pan
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
| | - Chengwei Wan
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
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Schuur EAG, Hicks Pries C, Mauritz M, Pegoraro E, Rodenhizer H, See C, Ebert C. Ecosystem and soil respiration radiocarbon detects old carbon release as a fingerprint of warming and permafrost destabilization with climate change. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2023; 381:20220201. [PMID: 37807688 PMCID: PMC10642809 DOI: 10.1098/rsta.2022.0201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 05/09/2023] [Indexed: 10/10/2023]
Abstract
The permafrost region has accumulated organic carbon in cold and waterlogged soils over thousands of years and now contains three times as much carbon as the atmosphere. Global warming is degrading permafrost with the potential to accelerate climate change as increased microbial decomposition releases soil carbon as greenhouse gases. A 19-year time series of soil and ecosystem respiration radiocarbon from Alaska provides long-term insight into changing permafrost soil carbon dynamics in a warmer world. Nine per cent of ecosystem respiration and 23% of soil respiration observations had radiocarbon values more than 50‰ lower than the atmospheric value. Furthermore, the overall trend of ecosystem and soil respiration radiocarbon values through time decreased more than atmospheric radiocarbon values did, indicating that old carbon degradation was enhanced. Boosted regression tree analyses showed that temperature and moisture environmental variables had the largest relative influence on lower radiocarbon values. This suggested that old carbon degradation was controlled by warming/permafrost thaw and soil drying together, as waterlogged soil conditions could protect soil carbon from microbial decomposition even when thawed. Overall, changing conditions increasingly favoured the release of old carbon, which is a definitive fingerprint of an accelerating feedback to climate change as a consequence of warming and permafrost destabilization. This article is part of the Theo Murphy meeting issue 'Radiocarbon in the Anthropocene'.
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Affiliation(s)
- Edward A. G. Schuur
- Center for Ecosystem Science and Society, and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Caitlin Hicks Pries
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Marguerite Mauritz
- Biological Sciences, University of Texas at El Paso, 500 West University Avenue, El Paso, TX 79902, USA
| | - Elaine Pegoraro
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Lab, Berkeley, CA, USA
| | | | - Craig See
- Center for Ecosystem Science and Society, and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Chris Ebert
- Center for Ecosystem Science and Society, and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
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4
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Scheel M, Zervas A, Rijkers R, Tveit AT, Ekelund F, Campuzano Jiménez F, Christensen TR, Jacobsen CS. Abrupt permafrost thaw triggers activity of copiotrophs and microbiome predators. FEMS Microbiol Ecol 2023; 99:fiad123. [PMID: 37796894 PMCID: PMC10599396 DOI: 10.1093/femsec/fiad123] [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: 03/01/2023] [Revised: 08/31/2023] [Accepted: 10/04/2023] [Indexed: 10/07/2023] Open
Abstract
Permafrost soils store a substantial part of the global soil carbon and nitrogen. However, global warming causes abrupt erosion and gradual thaw, which make these stocks vulnerable to microbial decomposition into greenhouse gases. Here, we investigated the microbial response to abrupt in situ permafrost thaw. We sequenced the total RNA of a 1 m deep soil core consisting of up to 26 500-year-old permafrost material from an active abrupt erosion site. We analysed the microbial community in the active layer soil, the recently thawed, and the intact permafrost, and found maximum RNA:DNA ratios in recently thawed permafrost indicating a high microbial activity. In thawed permafrost, potentially copiotrophic Burkholderiales and Sphingobacteriales, but also microbiome predators dominated the community. Overall, both thaw-dependent and long-term soil properties significantly correlated with changes in community composition, as did microbiome predator abundance. Bacterial predators were dominated in shallower depths by Myxococcota, while protozoa, especially Cercozoa and Ciliophora, almost tripled in relative abundance in thawed layers. Our findings highlight the ecological importance of a diverse interkingdom and active microbial community highly abundant in abruptly thawing permafrost, as well as predation as potential biological control mechanism.
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Affiliation(s)
- Maria Scheel
- Department of Environmental Science, Aarhus University, Roskilde 4000, Denmark
- Department of Ecoscience, Aarhus University, Roskilde 4000, Denmark
| | - Athanasios Zervas
- Department of Environmental Science, Aarhus University, Roskilde 4000, Denmark
| | - Ruud Rijkers
- Department of Ecological Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
- Department of Environmental Science, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Alexander T Tveit
- Department of Arctic and Marine Biology, University of Tromsø, Tromsø 9019, Norway
| | - Flemming Ekelund
- Department of Environmental Science, Aarhus University, Roskilde 4000, Denmark
- Department of Biology, Copenhagen University, DK-2200 Copenhagen, Denmark
| | | | - Torben R Christensen
- Department of Ecoscience, Aarhus University, Roskilde 4000, Denmark
- Water, Energy and Environmental Engineering Research Unit, University of Oulu, FI-90014 Oulu, Finland
| | - Carsten S Jacobsen
- Department of Environmental Science, Aarhus University, Roskilde 4000, Denmark
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5
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Qin Y, Wang N, Zheng L, Li Q, Wang L, Xu X, Yin X. Study of Archaeal Diversity in the Arctic Meltwater Lake Region. BIOLOGY 2023; 12:1023. [PMID: 37508452 PMCID: PMC10376139 DOI: 10.3390/biology12071023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 07/04/2023] [Accepted: 07/16/2023] [Indexed: 07/30/2023]
Abstract
Two typical lakes formed from meltwater in the Ny-Ålesund area were taken as the study subjects in 2018. To investigate the archaeal community compositions of the two lakes, 16S rRNA genes from soil samples from the intertidal and subtidal zones of the two lakes were sequenced with high throughput. At the phylum level, the intertidal zone was dominated by Crenarchaeota and the subtidal zone was dominated by Halobacter; at the genus level, the intertidal zone was dominated by Nitrososphaeraceae_unclassified and Candidatus_Nitrocosmicus, while the subtidal zone was dominated by Methanoregula. The soil physicochemical factors pH, moisture content (MC), total organic carbon (TOC), total organic nitrogen (TON), nitrite nitrogen (NO2--N), and nitrate nitrogen (NO3--N) were significantly different in the intertidal and subtidal zones of the lake. By redundancy analysis, the results indicated that NH4+-N, SiO32--Si, MC, NO3--N, and NO2--N have had highly significant effects on the archaeal diversity and distribution. A weighted gene co-expression network analysis (WGCNA) was used to search for hub archaea associated with physicochemical factors. The results suggested that these physicochemical factors play important roles in the diversity and structure of the archaeal community at different sites by altering the abundance of certain hub archaea. In addition, Woesearchaeales was found to be the hub archaea genus at every site.
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Affiliation(s)
- Yiling Qin
- First Institute of Oceanography, Ministry of Natural Resources, Qingdao 266061, China
| | - Nengfei Wang
- School of Chemistry and Chemical Engineering, Linyi University, Linyi 276000, China
| | - Li Zheng
- First Institute of Oceanography, Ministry of Natural Resources, Qingdao 266061, China
| | - Qinxin Li
- College of Chemistry and Chemical Engineering, Qingdao University, Qingdao 266071, China
| | - Long Wang
- Department of Bioengineering, College of Marine Sciences and Biological Engineering, Qingdao University of Science & Technology, Qingdao 266042, China
| | - Xiaoyu Xu
- School of Chemistry and Chemical Engineering, Linyi University, Linyi 276000, China
| | - Xiaofei Yin
- First Institute of Oceanography, Ministry of Natural Resources, Qingdao 266061, China
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Hamm A, Magnússon RÍ, Khattak AJ, Frampton A. Continentality determines warming or cooling impact of heavy rainfall events on permafrost. Nat Commun 2023; 14:3578. [PMID: 37328462 DOI: 10.1038/s41467-023-39325-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 06/07/2023] [Indexed: 06/18/2023] Open
Abstract
Permafrost thaw can cause an intensification of climate change through the release of carbon as greenhouse gases. While the effect of air temperature on permafrost thaw is well quantified, the effect of rainfall is highly variable and not well understood. Here, we provide a literature review of studies reporting on effects of rainfall on ground temperatures in permafrost environments and use a numerical model to explore the underlying physical mechanisms under different climatic conditions. Both the evaluated body of literature and the model simulations indicate that continental climates are likely to show a warming of the subsoil and hence increased end of season active layer thickness, while maritime climates tend to respond with a slight cooling effect. This suggests that dry regions with warm summers are prone to more rapid permafrost degradation under increased occurrences of heavy rainfall events in the future, which can potentially accelerate the permafrost carbon feedback.
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Affiliation(s)
- Alexandra Hamm
- Department of Physical Geography, Stockholm University, Stockholm, Sweden.
- Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden.
| | - Rúna Í Magnússon
- Plant Ecology and Nature Conservation Group, Wageningen University, Wageningen, Netherlands
| | - Ahmad Jan Khattak
- NOAA Affiliate at Lynker, Office of Water Prediction, National Water Center, Tuscaloosa, AL, USA
| | - Andrew Frampton
- Department of Physical Geography, Stockholm University, Stockholm, Sweden
- Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
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7
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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: 7] [Impact Index Per Article: 7.0] [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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8
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Distinct Growth Responses of Tundra Soil Bacteria to Short-Term and Long-Term Warming. Appl Environ Microbiol 2023; 89:e0154322. [PMID: 36847530 PMCID: PMC10056963 DOI: 10.1128/aem.01543-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
Increases in Arctic temperatures have thawed permafrost and accelerated tundra soil microbial activity, releasing greenhouse gases that amplify climate warming. Warming over time has also accelerated shrub encroachment in the tundra, altering plant input abundance and quality, and causing further changes to soil microbial processes. To better understand the effects of increased temperature and the accumulated effects of climate change on soil bacterial activity, we quantified the growth responses of individual bacterial taxa to short-term warming (3 months) and long-term warming (29 years) in moist acidic tussock tundra. Intact soil was assayed in the field for 30 days using 18O-labeled water, from which taxon-specific rates of 18O incorporation into DNA were estimated as a proxy for growth. Experimental treatments warmed the soil by approximately 1.5°C. Short-term warming increased average relative growth rates across the assemblage by 36%, and this increase was attributable to emergent growing taxa not detected in other treatments that doubled the diversity of growing bacteria. However, long-term warming increased average relative growth rates by 151%, and this was largely attributable to taxa that co-occurred in the ambient temperature controls. There was also coherence in relative growth rates within broad taxonomic levels with orders tending to have similar growth rates in all treatments. Growth responses tended to be neutral in short-term warming and positive in long-term warming for most taxa and phylogenetic groups co-occurring across treatments regardless of phylogeny. Taken together, growing bacteria responded distinctly to short-term and long-term warming, and taxa growing in each treatment exhibited deep phylogenetic organization. IMPORTANCE Soil carbon stocks in the tundra and underlying permafrost have become increasingly vulnerable to microbial decomposition due to climate change. The microbial responses to Arctic warming must be understood in order to predict the effects of future microbial activity on carbon balance in a warming Arctic. In response to our warming treatments, tundra soil bacteria grew faster, consistent with increased rates of decomposition and carbon flux to the atmosphere. Our findings suggest that bacterial growth rates may continue to increase in the coming decades as faster growth is driven by the accumulated effects of long-term warming. Observed phylogenetic organization of bacterial growth rates may also permit taxonomy-based predictions of bacterial responses to climate change and inclusion into ecosystem models.
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9
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Qi Q, Zhao J, Tian R, Zeng Y, Xie C, Gao Q, Dai T, Wang H, He JS, Konstantinidis KT, Yang Y, Zhou J, Guo X. Microbially enhanced methane uptake under warming enlarges ecosystem carbon sink in a Tibetan alpine grassland. GLOBAL CHANGE BIOLOGY 2022; 28:6906-6920. [PMID: 36191158 DOI: 10.1111/gcb.16444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 08/10/2022] [Accepted: 09/02/2022] [Indexed: 05/25/2023]
Abstract
The alpine grasslands of the Tibetan Plateau store 23.2 Pg soil organic carbon, which becomes susceptible to microbial degradation with climate warming. However, accurate prediction of how the soil carbon stock changes under future climate warming is hampered by our limited understanding of belowground complex microbial communities. Here, we show that 4 years of warming strongly stimulated methane (CH4 ) uptake by 93.8% and aerobic respiration (CO2 ) by 11.3% in the soils of alpine grassland ecosystem. Due to no significant effects of warming on net ecosystem CO2 exchange (NEE), the warming-stimulated CH4 uptake enlarged the carbon sink capacity of whole ecosystem. Furthermore, precipitation alternation did not alter such warming effects, despite the significant effects of precipitation on NEE and soil CH4 fluxes were observed. Metagenomic sequencing revealed that warming led to significant shifts in the overall microbial community structure and the abundances of functional genes, which contrasted to no detectable changes after 2 years of warming. Carbohydrate utilization genes were significantly increased by warming, corresponding with significant increases in soil aerobic respiration. Increased methanotrophic genes and decreased methanogenic genes were observed under warming, which significantly (R2 = .59, p < .001) correlated with warming-enhanced CH4 uptakes. Furthermore, 212 metagenome-assembled genomes were recovered, including many populations involved in the degradation of various organic matter and a highly abundant methylotrophic population of the Methyloceanibacter genus. Collectively, our results provide compelling evidence that specific microbial functional traits for CH4 and CO2 cycling processes respond to climate warming with differential effects on soil greenhouse gas emissions. Alpine grasslands may play huge roles in mitigating climate warming through such microbially enhanced CH4 uptake.
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Affiliation(s)
- Qi Qi
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China
| | - Jianshu Zhao
- School of Civil and Environmental Engineering and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Renmao Tian
- Institute for Food Safety and Health, Illinois Institute of Technology, Chicago, Illinois, USA
| | - Yufei Zeng
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China
| | - Changyi Xie
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China
| | - Qun Gao
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China
| | - Tianjiao Dai
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China
| | - Hao Wang
- State Key Laboratory of Grassland Agro-Ecosystems, and College of Ecology, Lanzhou University, Lanzhou, China
| | - Jin-Sheng He
- State Key Laboratory of Grassland Agro-Ecosystems, and College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China
- College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, Peking University, Beijing, China
| | - Konstantinos T Konstantinidis
- School of Civil and Environmental Engineering and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Yunfeng Yang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China
| | - Jizhong Zhou
- Institute for Environmental Genomics, University of Oklahoma, Norman, Oklahoma, USA
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
- Earth and Environmental Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Xue Guo
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China
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10
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Feng X, Duan L, Kurylyk BL, Cai T. Impacts of permafrost thaw on streamflow recession in a discontinuous permafrost watershed of northeastern China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 847:157624. [PMID: 35905958 DOI: 10.1016/j.scitotenv.2022.157624] [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: 04/15/2022] [Revised: 07/20/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
Permafrost thaw due to climate change is altering terrestrial hydrological processes by increasing ground hydraulic conductivity and surface and subsurface hydrologic connectivity across the pan-Arctic. Understanding how runoff responds to changes in hydrologic processes and conditions induced by permafrost thaw is critical for water resources management in high-latitude and high-altitude regions. In this study, we analyzed streamflow recession characteristics for 1964-2016 for the Tahe watershed located at the southern margin of the permafrost region in Eurasia. Results reveal a link between streamflow recession and permafrost degradation as indicated by the statistical analyses of streamflow and the modeled ground warming and active layer thickening. The recession constant and the active layer temperatures at depths of 5, 40, 100, and 200 cm simulated by the backpropagation neural network model significantly increased during the study period from 1972 to 2020 due to intensified climate warming in northeastern China. The onset of seasonal active layer thaw was advanced by 10 days, and the modeled active layer thickness increased by 54 cm in this period. The average annual streamflow recession time increased by 11.5 days (+53 %) from the warming period (1972-1988) to the thawing period (1989-2016), with these periods determined from breakpoint analysis. These hydrologic changes arose from increased catchment storage and were correlated to increased active layer thickness and longer seasonal thawing periods. These results highlight that permafrost degradation can significantly extend the recession flow duration in a watershed underlain by discontinuous, sporadic, and isolated permafrost, and thereby alter flooding dynamics and water resources in the southern margin of the Eurasian permafrost region.
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Affiliation(s)
- Xinyue Feng
- School of Forestry, Northeast Forestry University, 26 Hexing Road, Harbin 150040, China; Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, 26 Hexing Road, Harbin 150040, China
| | - Liangliang Duan
- School of Forestry, Northeast Forestry University, 26 Hexing Road, Harbin 150040, China; Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, 26 Hexing Road, Harbin 150040, China.
| | - Barret L Kurylyk
- Department of Civil and Resource Engineering and Centre for Water Resources Studies, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Tijiu Cai
- School of Forestry, Northeast Forestry University, 26 Hexing Road, Harbin 150040, China; Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, 26 Hexing Road, Harbin 150040, China.
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11
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Ernakovich JG, Barbato RA, Rich VI, Schädel C, Hewitt RE, Doherty SJ, Whalen E, Abbott BW, Barta J, Biasi C, Chabot CL, Hultman J, Knoblauch C, Vetter M, Leewis M, Liebner S, Mackelprang R, Onstott TC, Richter A, Schütte U, Siljanen HMP, Taş N, Timling I, Vishnivetskaya TA, Waldrop MP, Winkel M. Microbiome assembly in thawing permafrost and its feedbacks to climate. GLOBAL CHANGE BIOLOGY 2022; 28:5007-5026. [PMID: 35722720 PMCID: PMC9541943 DOI: 10.1111/gcb.16231] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 03/24/2022] [Indexed: 05/15/2023]
Abstract
The physical and chemical changes that accompany permafrost thaw directly influence the microbial communities that mediate the decomposition of formerly frozen organic matter, leading to uncertainty in permafrost-climate feedbacks. Although changes to microbial metabolism and community structure are documented following thaw, the generality of post-thaw assembly patterns across permafrost soils of the world remains uncertain, limiting our ability to predict biogeochemistry and microbial community responses to climate change. Based on our review of the Arctic microbiome, permafrost microbiology, and community ecology, we propose that Assembly Theory provides a framework to better understand thaw-mediated microbiome changes and the implications for community function and climate feedbacks. This framework posits that the prevalence of deterministic or stochastic processes indicates whether the community is well-suited to thrive in changing environmental conditions. We predict that on a short timescale and following high-disturbance thaw (e.g., thermokarst), stochasticity dominates post-thaw microbiome assembly, suggesting that functional predictions will be aided by detailed information about the microbiome. At a longer timescale and lower-intensity disturbance (e.g., active layer deepening), deterministic processes likely dominate, making environmental parameters sufficient for predicting function. We propose that the contribution of stochastic and deterministic processes to post-thaw microbiome assembly depends on the characteristics of the thaw disturbance, as well as characteristics of the microbial community, such as the ecological and phylogenetic breadth of functional guilds, their functional redundancy, and biotic interactions. These propagate across space and time, potentially providing a means for predicting the microbial forcing of greenhouse gas feedbacks to global climate change.
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Affiliation(s)
- Jessica G. Ernakovich
- Natural Resources and the EnvironmentUniversity of New HampshireDurhamNew HampshireUSA
- Molecular, Cellular and Biomedical SciencesUniversity of New HampshireDurhamNew HampshireUSA
- EMergent Ecosystem Response to ChanGE (EMERGE) Biology Integration Institute
| | - Robyn A. Barbato
- U.S. Army Cold Regions Research and Engineering LaboratoryHanoverNew HampshireUSA
| | - Virginia I. Rich
- EMergent Ecosystem Response to ChanGE (EMERGE) Biology Integration Institute
- Microbiology DepartmentOhio State UniversityColumbusOhioUSA
- Byrd Polar and Climate Research CenterOhio State UniversityColombusOhioUSA
- Center of Microbiome ScienceOhio State UniversityColombusOhioUSA
| | - Christina Schädel
- Center for Ecosystem Science and SocietyNorthern Arizona UniversityFlagstaffArizonaUSA
| | - Rebecca E. Hewitt
- Center for Ecosystem Science and SocietyNorthern Arizona UniversityFlagstaffArizonaUSA
- Department of Environmental StudiesAmherst CollegeAmherstMassachusettsUSA
| | - Stacey J. Doherty
- Molecular, Cellular and Biomedical SciencesUniversity of New HampshireDurhamNew HampshireUSA
- U.S. Army Cold Regions Research and Engineering LaboratoryHanoverNew HampshireUSA
| | - Emily D. Whalen
- Natural Resources and the EnvironmentUniversity of New HampshireDurhamNew HampshireUSA
| | - Benjamin W. Abbott
- Department of Plant and Wildlife SciencesBrigham Young UniversityProvoUtahUSA
| | - Jiri Barta
- Centre for Polar EcologyUniversity of South BohemiaCeske BudejoviceCzech Republic
| | - Christina Biasi
- Department of Environmental and Biological SciencesUniversity of Eastern FinlandKuopioFinland
| | - Chris L. Chabot
- California State University NorthridgeNorthridgeCaliforniaUSA
| | | | - Christian Knoblauch
- Institute of Soil ScienceUniversität HamburgHamburgGermany
- Center for Earth System Research and SustainabilityUniversität HamburgHamburgGermany
| | - Maggie C. Y. Lau Vetter
- Department of GeosciencesPrinceton UniversityPrincetonNew JerseyUSA
- Laboratory of Extraterrestrial Ocean Systems (LEOS)Institute of Deep‐sea Science and EngineeringChinese Academy of SciencesSanyaChina
| | - Mary‐Cathrine Leewis
- U.S. Geological Survey, GeologyMinerals, Energy and Geophysics Science CenterMenlo ParkCaliforniaUSA
- Agriculture and Agri‐Food CanadaQuebec Research and Development CentreQuebecQuebecCanada
| | - Susanne Liebner
- GFZ German Research Centre for GeosciencesSection GeomicrobiologyPotsdamGermany
| | | | | | - Andreas Richter
- Centre for Microbiology and Environmental Systems ScienceUniversity of ViennaViennaAustria
- Austrian Polar Research InstituteViennaAustria
| | | | - Henri M. P. Siljanen
- Department of Environmental and Biological SciencesUniversity of Eastern FinlandKuopioFinland
| | - Neslihan Taş
- Lawrence Berkeley National LaboratoryBerkeleyCaliforniaUSA
| | | | - Tatiana A. Vishnivetskaya
- University of TennesseeKnoxvilleTennesseeUSA
- Institute of Physicochemical and Biological Problems of Soil SciencePushchinoRussia
| | - Mark P. Waldrop
- U.S. Geological Survey, GeologyMinerals, Energy and Geophysics Science CenterMenlo ParkCaliforniaUSA
| | - Matthias Winkel
- GFZ German Research Centre for GeosciencesInterface GeochemistryPotsdamGermany
- BfR Federal Institute for Risk AssessmentBerlinGermany
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12
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Divergent changes in particulate and mineral-associated organic carbon upon permafrost thaw. Nat Commun 2022; 13:5073. [PMID: 36038568 PMCID: PMC9424277 DOI: 10.1038/s41467-022-32681-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 08/11/2022] [Indexed: 11/21/2022] Open
Abstract
Permafrost thaw can stimulate microbial decomposition and induce soil carbon (C) loss, potentially triggering a positive C-climate feedback. However, earlier observations have concentrated on bulk soil C dynamics upon permafrost thaw, with limited evidence involving soil C fractions. Here, we explore how the functionally distinct fractions, including particulate and mineral-associated organic C (POC and MAOC) as well as iron-bound organic C (OC-Fe), respond to permafrost thaw using systematic measurements derived from one permafrost thaw sequence and five additional thermokarst-impacted sites on the Tibetan Plateau. We find that topsoil POC content substantially decreases, while MAOC content remains stable and OC-Fe accumulates due to the enriched Fe oxides after permafrost thaw. Moreover, the proportion of MAOC and OC-Fe increases along the thaw sequence and at most of the thermokarst-impacted sites. The relatively enriched stable soil C fractions would alleviate microbial decomposition and weaken its feedback to climate warming over long-term thermokarst development. Based on observations from thermokarst-impacted sites on the Tibetan Plateau, the authors find substantial particulate organic carbon loss but stable mineral-associated organic carbon and enriched iron-bound organic carbon upon permafrost thaw.
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13
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Hewitt RE, Alexander HD, Izbicki B, Loranty MM, Natali SM, Walker XJ, Mack MC. Increasing tree density accelerates stand‐level nitrogen cycling at the taiga–tundra ecotone in northeastern Siberia. Ecosphere 2022. [DOI: 10.1002/ecs2.4175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Rebecca E. Hewitt
- Center for Ecosystem Science and Society, Department of Biological Sciences Northern Arizona University Flagstaff Arizona USA
- Department of Environmental Studies Amherst College Amherst Massachusetts USA
| | | | - Brian Izbicki
- Center for Ecosystem Science and Society, Department of Biological Sciences Northern Arizona University Flagstaff Arizona USA
| | | | | | - Xanthe J. Walker
- Center for Ecosystem Science and Society, Department of Biological Sciences Northern Arizona University Flagstaff Arizona USA
| | - Michelle C. Mack
- Center for Ecosystem Science and Society, Department of Biological Sciences Northern Arizona University Flagstaff Arizona USA
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14
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Drying–Wetting Changes of Surface Soil Moisture and the Influencing Factors in Permafrost Regions of the Qinghai-Tibet Plateau, China. REMOTE SENSING 2022. [DOI: 10.3390/rs14122915] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Soil moisture (SM), an important variable in water conversion between the atmosphere and terrestrial ecosystems, plays a crucial role in ecological processes and the evolution of terrestrial ecosystems. Analyzing and exploring SM’s processes and influencing factors in different permafrost regions of the Qinghai-Tibet Plateau (QTP) can better serve the regional ecological security, disaster warning, water management, etc. However, the changes and future trends of SM on the QTP in recent decades are uncertain, and the main factors affecting SM are not fully understood. The study used SM observations, the Global Land Evapotranspiration Amsterdam Model (GLEAM) SM products, meteorological and vegetation data, Mann–Kendall test, Theil–Sen estimation, Ensemble Empirical Mode Decomposition (EEMD), and correlation methods to analyze and explore the characteristics and influencing factors of SM change in different permafrost regions of the QTP. The results show that: (1) At the pixel scale, GLEAM SM products can better reflect SM changes in the QTP in the warm season. The seasonal permafrost region is closer to the real SM than the permanent region, with a median correlation coefficient (R) of 0.738, median bias of 0.043 m3 m−3, and median unbiased root mean square errors (ubRMSE) of 0.031 m3 m−3. (2) The average SM in the QTP warm season increased at a rate of 0.573 × 10−3 m3 m−3 yr−1 over the recent 40 years, and the trend accelerated from 2005–2020. In 64.31% of the region, the soil was significantly wetted, mainly distributed in the permafrost region, which showed that the wetting rate in the dry region was faster than in the wet region. However, the wetting trend does not have a long-term continuity and has a pattern of “wetting–drying-wetting” on interannual and decadal levels, especially in the seasonal permafrost region. (3) More than 65% of the SM wetting trend on the QTP is caused by temperature, precipitation, and vegetation. However, there is apparent spatial heterogeneity in the different permafrost regions and vegetation cover conditions, and the three factors have a more substantial explanatory power for SM changes in the seasonal permafrost region. With the global climate change, the synergistic SM–Climate–Vegetation effect on the QTP tends to be more evident in the seasonal permafrost region.
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15
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Yu RQ, Barkay T. Microbial mercury transformations: Molecules, functions and organisms. ADVANCES IN APPLIED MICROBIOLOGY 2022; 118:31-90. [PMID: 35461663 DOI: 10.1016/bs.aambs.2022.03.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Mercury (Hg) methylation, methylmercury (MeHg) demethylation, and inorganic redox transformations of Hg are microbe-mediating processes that determine the fate and cycling of Hg and MeHg in many environments, and by doing so influence the health of humans and wild life. The discovery of the Hg methylation genes, hgcAB, in the last decade together with advances in high throughput and genome sequencing methods, have resulted in an expanded appreciation of the diversity of Hg methylating microbes. This review aims to describe experimentally confirmed and recently discovered hgcAB gene-carrying Hg methylating microbes; phylogenetic and taxonomic analyses are presented. In addition, the current knowledge on transformation mechanisms, the organisms that carry them out, and the impact of environmental parameters on Hg methylation, MeHg demethylation, and inorganic Hg reduction and oxidation is summarized. This knowledge provides a foundation for future action toward mitigating the impact of environmental Hg pollution.
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Affiliation(s)
- Ri-Qing Yu
- Department of Biology, University of Texas at Tyler, Tyler, TX, United States.
| | - Tamar Barkay
- Department of Biochemistry and Microbiology, Rutgers, The State University of New Jersey, New Brunswick, NJ, United States
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16
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Scheel M, Zervas A, Jacobsen CS, Christensen TR. Microbial Community Changes in 26,500-Year-Old Thawing Permafrost. Front Microbiol 2022; 13:787146. [PMID: 35401488 PMCID: PMC8988141 DOI: 10.3389/fmicb.2022.787146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 02/09/2022] [Indexed: 12/02/2022] Open
Abstract
Northern permafrost soils store more than half of the global soil carbon. Frozen for at least two consecutive years, but often for millennia, permafrost temperatures have increased drastically in the last decades. The resulting thermal erosion leads not only to gradual thaw, resulting in an increase of seasonally thawing soil thickness, but also to abrupt thaw events, such as sudden collapses of the soil surface. These could affect 20% of the permafrost zone and half of its organic carbon, increasing accessibility for deeper rooting vegetation and microbial decomposition into greenhouse gases. Knowledge gaps include the impact of permafrost thaw on the soil microfauna as well as key taxa to change the microbial mineralization of ancient permafrost carbon stocks during erosion. Here, we present the first sequencing study of an abrupt permafrost erosion microbiome in Northeast Greenland, where a thermal erosion gully collapsed in the summer of 2018, leading to the thawing of 26,500-year-old permafrost material. We investigated which soil parameters (pH, soil carbon content, age and moisture, organic and mineral horizons, and permafrost layers) most significantly drove changes of taxonomic diversity and the abundance of soil microorganisms in two consecutive years of intense erosion. Sequencing of the prokaryotic 16S rRNA and fungal ITS2 gene regions at finely scaled depth increments revealed decreasing alpha diversity with depth, soil age, and pH. The most significant drivers of variation were found in the soil age, horizons, and permafrost layer for prokaryotic and fungal beta diversity. Permafrost was mainly dominated by Proteobacteria and Firmicutes, with Polaromonas identified as the most abundant taxon. Thawed permafrost samples indicated increased abundance of several copiotrophic phyla, such as Bacteroidia, suggesting alterations of carbon utilization pathways within eroding permafrost.
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Affiliation(s)
- Maria Scheel
- Department of Ecoscience, Arctic Research Centre, Aarhus University, Roskilde, Denmark
| | - Athanasios Zervas
- Department of Environmental Science, Aarhus University, Roskilde, Denmark
| | | | - Torben R. Christensen
- Department of Ecoscience, Arctic Research Centre, Aarhus University, Roskilde, Denmark
- Oulanka Research Station, Oulu University, Oulu, Finland
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17
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PermaBN: A Bayesian Network framework to help predict permafrost thaw in the Arctic. ECOL INFORM 2022. [DOI: 10.1016/j.ecoinf.2022.101601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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18
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Rogers A, Serbin SP, Way DA. Reducing model uncertainty of climate change impacts on high latitude carbon assimilation. GLOBAL CHANGE BIOLOGY 2022; 28:1222-1247. [PMID: 34689389 DOI: 10.1111/gcb.15958] [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: 07/16/2021] [Accepted: 09/17/2021] [Indexed: 06/13/2023]
Abstract
The Arctic-Boreal Region (ABR) has a large impact on global vegetation-atmosphere interactions and is experiencing markedly greater warming than the rest of the planet, a trend that is projected to continue with anticipated future emissions of CO2 . The ABR is a significant source of uncertainty in estimates of carbon uptake in terrestrial biosphere models such that reducing this uncertainty is critical for more accurately estimating global carbon cycling and understanding the response of the region to global change. Process representation and parameterization associated with gross primary productivity (GPP) drives a large amount of this model uncertainty, particularly within the next 50 years, where the response of existing vegetation to climate change will dominate estimates of GPP for the region. Here we review our current understanding and model representation of GPP in northern latitudes, focusing on vegetation composition, phenology, and physiology, and consider how climate change alters these three components. We highlight challenges in the ABR for predicting GPP, but also focus on the unique opportunities for advancing knowledge and model representation, particularly through the combination of remote sensing and traditional boots-on-the-ground science.
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Affiliation(s)
- Alistair Rogers
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, New York, USA
| | - Shawn P Serbin
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, New York, USA
| | - Danielle A Way
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, New York, USA
- Department of Biology, University of Western Ontario, London, Ontario, Canada
- Nicholas School of the Environment, Duke University, Durham, North Carolina, USA
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19
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Kim H, Kim M, Kim S, Lee YM, Shin SC. Characterization of antimicrobial resistance genes and virulence factor genes in an Arctic permafrost region revealed by metagenomics. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 294:118634. [PMID: 34875269 DOI: 10.1016/j.envpol.2021.118634] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 11/29/2021] [Accepted: 12/03/2021] [Indexed: 06/13/2023]
Abstract
Antimicrobial resistance genes (ARGs) and virulence factor genes (VFGs) constitute a serious threat to public health, and climate change has been predicted to affect the increase in bacterial pathogens harboring ARGs and VFGs. However, studies on bacterial pathogens and their ARGs and VFGs in permafrost region have received limited attention. In this study, a metagenomic approach was applied to a comprehensive survey to detect potential ARGs, VFGs, and pathogenic antibiotic resistant bacteria (PARB) carrying both ARGs and VFGs in the active layer and permafrost. Overall, 70 unique ARGs against 18 antimicrobial drug classes and 599 VFGs classified as 38 virulence factors were detected in the Arctic permafrost region. Eight genes with mobile genetic elements (MGEs) carrying ARGs were identified; most MGEs were classified as phages. In the metagenome-assembled genomes, the presence of 15 PARB was confirmed. The soil profile showed that the transcripts per million (TPM) values of ARGs and VFGs in the sub-soil horizon were significantly lower than those in the top soil horizon. Based on the TPM value of each gene, major ARGs, VFGs, and these genes in PARB from the Arctic permafrost region were identified and their distribution was confirmed. The major host bacteria for ARGs and VFGs and PARB were identified. A comparison of the percentage identity distribution of ARGs and VFGs to reference databases indicated that ARGs and VFGs in the Arctic soils differ from previously identified genes. Our results may help understand the characteristics and distribution of ARGs, VFGs, and these genes in PARB in the Arctic permafrost region. This findings suggest that the Arctic permafrost region may serve as potential reservoirs for ARGs, VFGs, and PARB. These genes could pose a new threat to human health if they are released by permafrost thawing owing to global warming and propagate to other regions.
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Affiliation(s)
- Heesoo Kim
- Division of Life Sciences, Korea Polar Research Institute, Incheon, 21990, Republic of Korea
| | - Mincheol Kim
- Division of Life Sciences, Korea Polar Research Institute, Incheon, 21990, Republic of Korea
| | - Sanghee Kim
- Division of Life Sciences, Korea Polar Research Institute, Incheon, 21990, Republic of Korea
| | - Yung Mi Lee
- Division of Life Sciences, Korea Polar Research Institute, Incheon, 21990, Republic of Korea
| | - Seung Chul Shin
- Division of Life Sciences, Korea Polar Research Institute, Incheon, 21990, Republic of Korea.
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20
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Gao W, Sun W, Xu X. Permafrost response to temperature rise in carbon and nutrient cycling: Effects from habitat-specific conditions and factors of warming. Ecol Evol 2021; 11:16021-16033. [PMID: 34824808 PMCID: PMC8601908 DOI: 10.1002/ece3.8271] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 09/30/2021] [Accepted: 10/12/2021] [Indexed: 11/06/2022] Open
Abstract
Permafrost is experiencing climate warming at a rate that is two times faster than the rest of the Earth's surface. However, it is still lack of a quantitative basis for predicting the functional stability of permafrost ecosystems in carbon (C) and nutrient cycling. We compiled the data of 708 observations from 89 air-warming experiments in the Northern Hemisphere and characterized the general effects of temperature increase on permafrost C exchange and balance, biomass production, microbial biomass, soil nutrients, and vegetation N dynamics through a meta-analysis. Also, an investigation was made on how responses might change with habitat-specific (e.g., plant functional groups and soil moisture status) conditions and warming variables (e.g., warming phases, levels, and timing). The net ecosystem C exchange (NEE) was found to be downregulated by warming as a result of a stronger sensitivity to warming in respiration (15.6%) than in photosynthesis (6.2%). Vegetation usually responded to warming by investing more C to the belowground, as belowground biomass increased much more (30.1%) than aboveground biomass (2.9%). Warming had a minor effect on microbial biomass. Warming increased soil ammonium and nitrate concentrations. What's more, a synthesis of 70 observations from 11 herbs and 9 shrubs revealed a 2.5% decline of N in green leaves. Compared with herbs, shrubs had a stronger response to respiration and had a decline in green leaf N to a greater extent. Not only in dry condition did green leaf N decline with warming but also in wet conditions. Warming in nongrowing seasons would negatively affect soil water, C uptake, and biomass production during growing seasons. Permafrost C loss and vegetation N decline may increase with warming levels and timing. Overall, these findings suggest that besides a positive C cycling-climate feedback, there will be a negative feedback between permafrost nutrient cycling and climate warming.
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Affiliation(s)
- Wenlong Gao
- National‐Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South ChinaGuangdong Key Laboratory of Integrated Agro‐environmental Pollution Control and ManagementInstitute of Eco‐environmental and Soil SciencesGuangdong Academy of SciencesGuangzhouChina
- Hainan Key Laboratory of Tropical Eco‐Circular AgricultureEnvironment and Plant Protection InstituteChinese Academy of Tropical Agricultural SciencesHaikouChina
- Hainan Danzhou Tropical Agro‐ecosystem National Observation and Research StationDanzhouChina
| | - Weimin Sun
- National‐Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South ChinaGuangdong Key Laboratory of Integrated Agro‐environmental Pollution Control and ManagementInstitute of Eco‐environmental and Soil SciencesGuangdong Academy of SciencesGuangzhouChina
- School of EnvironmentHenan Normal UniversityXinxiangChina
- Key Laboratory of Yellow River and Huai River Water Environment and Pollution ControlMinistry of EducationBeijingChina
| | - Xingliang Xu
- Key Laboratory of Ecosystem Network Observation and ModelingInstitute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijingChina
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21
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Chen Y, Liu F, Kang L, Zhang D, Kou D, Mao C, Qin S, Zhang Q, Yang Y. Large-scale evidence for microbial response and associated carbon release after permafrost thaw. GLOBAL CHANGE BIOLOGY 2021; 27:3218-3229. [PMID: 33336478 DOI: 10.1111/gcb.15487] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 12/04/2020] [Indexed: 06/12/2023]
Abstract
Permafrost thaw could trigger the release of greenhouse gases through microbial decomposition of the large quantities of carbon (C) stored within frozen soils. However, accurate evaluation of soil C emissions from thawing permafrost is still a big challenge, partly due to our inadequate understanding about the response of microbial communities and their linkage with soil C release upon permafrost thaw. Based on a large-scale permafrost sampling across 24 sites on the Tibetan Plateau, we employed meta-genomic technologies (GeoChip and Illumina MiSeq sequencing) to explore the impacts of permafrost thaw (permafrost samples were incubated for 11 days at 5°C) on microbial taxonomic and functional communities, and then conducted a laboratory incubation to investigate the linkage of microbial taxonomic and functional diversity with soil C release after permafrost thaw. We found that bacterial and fungal α diversity decreased, but functional gene diversity and the normalized relative abundance of C degradation genes increased after permafrost thaw, reflecting the rapid microbial response to permafrost thaw. Moreover, both the microbial taxonomic and functional community structures differed between the thawed permafrost and formerly frozen soils. Furthermore, soil C release rate over five month incubation was associated with microbial functional diversity and C degradation gene abundances. By contrast, neither microbial taxonomic diversity nor community structure exhibited any significant effects on soil C release over the incubation period. These findings demonstrate that permafrost thaw could accelerate C emissions by altering the function potentials of microbial communities rather than taxonomic diversity, highlighting the crucial role of microbial functional genes in mediating the responses of permafrost C cycle to climate warming.
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Affiliation(s)
- Yongliang Chen
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- College of Resources and Environmental Sciences, China Agricultural University, Beijing, China
| | - Futing Liu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Tree Breeding and Cultivation of the State Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
| | - Luyao Kang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Dianye Zhang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Dan Kou
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Chao Mao
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Shuqi Qin
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qiwen Zhang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Yuanhe Yang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
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22
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Pegoraro EF, Mauritz ME, Ogle K, Ebert CH, Schuur EAG. Lower soil moisture and deep soil temperatures in thermokarst features increase old soil carbon loss after 10 years of experimental permafrost warming. GLOBAL CHANGE BIOLOGY 2021; 27:1293-1308. [PMID: 33305441 DOI: 10.1111/gcb.15481] [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: 05/28/2020] [Revised: 09/05/2020] [Accepted: 10/20/2020] [Indexed: 06/12/2023]
Abstract
Almost half of the global terrestrial soil carbon (C) is stored in the northern circumpolar permafrost region, where air temperatures are increasing two times faster than the global average. As climate warms, permafrost thaws and soil organic matter becomes vulnerable to greater microbial decomposition. Long-term soil warming of ice-rich permafrost can result in thermokarst formation that creates variability in environmental conditions. Consequently, plant and microbial proportional contributions to ecosystem respiration may change in response to long-term soil warming. Natural abundance δ13 C and Δ14 C of aboveground and belowground plant material, and of young and old soil respiration were used to inform a mixing model to partition the contribution of each source to ecosystem respiration fluxes. We employed a hierarchical Bayesian approach that incorporated gross primary productivity and environmental drivers to constrain source contributions. We found that long-term experimental permafrost warming introduced a soil hydrology component that interacted with temperature to affect old soil C respiration. Old soil C loss was suppressed in plots with warmer deep soil temperatures because they tended to be wetter. When soil volumetric water content significantly decreased in 2018 relative to 2016 and 2017, the dominant respiration sources shifted from plant aboveground and young soil respiration to old soil respiration. The proportion of ecosystem respiration from old soil C accounted for up to 39% of ecosystem respiration and represented a 30-fold increase compared to the wet-year average. Our findings show that thermokarst formation may act to moderate microbial decomposition of old soil C when soil is highly saturated. However, when soil moisture decreases, a higher proportion of old soil C is vulnerable to decomposition and can become a large flux to the atmosphere. As permafrost systems continue to change with climate, we must understand the thresholds that may propel these systems from a C sink to a source.
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Affiliation(s)
- Elaine F Pegoraro
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
- Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Marguerite E Mauritz
- Ecology and Evolutionary Biology, The University of Texas at El Paso, El Paso, TX, USA
| | - Kiona Ogle
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA
| | - Christopher H Ebert
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
| | - Edward A G Schuur
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
- Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
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23
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An Object-Based Approach for Mapping Tundra Ice-Wedge Polygon Troughs from Very High Spatial Resolution Optical Satellite Imagery. REMOTE SENSING 2021. [DOI: 10.3390/rs13040558] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Very high spatial resolution commercial satellite imagery can inform observation, mapping, and documentation of micro-topographic transitions across large tundra regions. The bridging of fine-scale field studies with pan-Arctic system assessments has until now been constrained by a lack of overlap in spatial resolution and geographical coverage. This likely introduced biases in climate impacts on, and feedback from the Arctic region to the global climate system. The central objective of this exploratory study is to develop an object-based image analysis workflow to automatically extract ice-wedge polygon troughs from very high spatial resolution commercial satellite imagery. We employed a systematic experiment to understand the degree of interoperability of knowledge-based workflows across distinct tundra vegetation units—sedge tundra and tussock tundra—focusing on the same semantic class. In our multi-scale trough modelling workflow, we coupled mathematical morphological filtering with a segmentation process to enhance the quality of image object candidates and classification accuracies. Employment of the master ruleset on sedge tundra reported classification accuracies of correctness of 0.99, completeness of 0.87, and F1 score of 0.92. When the master ruleset was applied to tussock tundra without any adaptations, classification accuracies remained promising while reporting correctness of 0.87, completeness of 0.77, and an F1 score of 0.81. Overall, results suggest that the object-based image analysis-based trough modelling workflow exhibits substantial interoperability across the terrain while producing promising classification accuracies. From an Arctic earth science perspective, the mapped troughs combined with the ArcticDEM can allow hydrological assessments of lateral connectivity of the rapidly changing Arctic tundra landscape, and repeated mapping can allow us to track fine-scale changes across large regions and that has potentially major implications on larger riverine systems.
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24
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Seitz TJ, Schütte UME, Drown DM. Soil Disturbance Affects Plant Productivity via Soil Microbial Community Shifts. Front Microbiol 2021; 12:619711. [PMID: 33597939 PMCID: PMC7882522 DOI: 10.3389/fmicb.2021.619711] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 01/08/2021] [Indexed: 11/13/2022] Open
Abstract
Recent advances in climate research have discovered that permafrost is particularly vulnerable to the changes occurring in the atmosphere and climate, especially in Alaska where 85% of the land is underlain by mostly discontinuous permafrost. As permafrost thaws, research has shown that natural and anthropogenic soil disturbance causes microbial communities to undergo shifts in membership composition and biomass, as well as in functional diversity. Boreal forests are home to many plants that are integral to the subsistence diets of many Alaska Native communities. Yet, it is unclear how the observed shifts in soil microbes can affect above ground plant communities that are relied on as a major source of food. In this study, we tested the hypothesis that microbial communities associated with permafrost thaw affect plant productivity by growing five plant species found in Boreal forests and Tundra ecosystems, including low-bush cranberry and bog blueberry, with microbial communities from the active layer soils of a permafrost thaw gradient. We found that plant productivity was significantly affected by the microbial soil inoculants. Plants inoculated with communities from above thawing permafrost showed decreased productivity compared to plants inoculated with microbes from undisturbed soils. We used metagenomic sequencing to determine that microbial communities from disturbed soils above thawing permafrost differ in taxonomy from microbial communities in undisturbed soils above intact permafrost. The combination of these results indicates that a decrease in plant productivity can be linked to soil disturbance driven changes in microbial community membership and abundance. These data contribute to an understanding of how microbial communities can be affected by soil disturbance and climate change, and how those community shifts can further influence plant productivity in Boreal forests and more broadly, ecosystem health.
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Affiliation(s)
- Taylor J. Seitz
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, United States
| | - Ursel M. E. Schütte
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, United States
| | - Devin M. Drown
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, United States
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, United States
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25
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Haan TJ, Drown DM. Unearthing Antibiotic Resistance Associated with Disturbance-Induced Permafrost Thaw in Interior Alaska. Microorganisms 2021; 9:116. [PMID: 33418967 PMCID: PMC7825290 DOI: 10.3390/microorganisms9010116] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 12/31/2020] [Accepted: 12/31/2020] [Indexed: 01/02/2023] Open
Abstract
Monitoring antibiotic resistance genes (ARGs) across ecological niches is critical for assessing the impacts distinct microbial communities have on the global spread of resistance. In permafrost-associated soils, climate and human driven disturbances augment near-surface thaw shifting the predominant bacteria that shape the resistome in overlying active layer soils. This thaw is of concern in Alaska, because 85% of land is underlain by permafrost, making soils especially vulnerable to disturbances. The goal of this study is to assess how soil disturbance, and the subsequent shift in community composition, will affect the types, abundance, and mobility of ARGs that compose the active layer resistome. We address this goal through the following aims: (1) assess resistance phenotypes through antibiotic susceptibility testing, and (2) analyze types, abundance, and mobility of ARGs through whole genome analyses of bacteria isolated from a disturbance-induced thaw gradient in Interior Alaska. We found a high proportion of isolates resistant to at least one of the antibiotics tested with the highest prevalence of resistance to ampicillin. The abundance of ARGs and proportion of resistant isolates increased with disturbance; however, the number of ARGs per isolate was explained more by phylogeny than isolation site. When compared to a global database of soil bacteria, RefSoil+, our isolates from the same genera had distinct ARGs with a higher proportion on plasmids. These results emphasize the hypothesis that both phylogeny and ecology shape the resistome and suggest that a shift in community composition as a result of disturbance-induced thaw will be reflected in the predominant ARGs comprising the active layer resistome.
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Affiliation(s)
- Tracie J. Haan
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK 99775, USA;
| | - Devin M. Drown
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK 99775, USA;
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
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26
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Detecting and Mapping Gas Emission Craters on the Yamal and Gydan Peninsulas, Western Siberia. GEOSCIENCES 2021. [DOI: 10.3390/geosciences11010021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Rapid climate warming at northern high latitudes is driving geomorphic changes across the permafrost zone. In the Yamal and Gydan peninsulas in western Siberia, subterranean accumulation of methane beneath or within ice-rich permafrost can create mounds at the land surface. Once over-pressurized by methane, these mounds can explode and eject frozen ground, forming a gas emission crater (GEC). While GECs pose a hazard to human populations and infrastructure, only a small number have been identified in the Yamal and Gydan peninsulas, where the regional distribution and frequency of GECs and other types of land surface change are relatively unconstrained. To understand the distribution of landscape change within 327,000 km2 of the Yamal-Gydan region, we developed a semi-automated multivariate change detection algorithm using satellite-derived surface reflectance, elevation, and water extent in the Google Earth Engine cloud computing platform. We found that 5% of the landscape changed from 1984 to 2017. The algorithm detected all seven GECs reported in the scientific literature and three new GEC-like features, and further revealed that retrogressive thaw slumps were more abundant than GECs. Our methodology can be refined to detect and better understand diverse types of land surface change and potentially mitigate risks across the northern permafrost zone.
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27
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Abstract
Analysis of climatic conditions for the period of instrumental measurement in Central Yakutia showed three periods with two different mean annual air temperature (MAAT) shifts. These periods were divided into 1930–1987 (base period A), 1988–2006 (period B) and 2007–2018 (period C) timelines. The MAAT during these three periods amounted −10.3, −8.6 and −7.4 °C, respectively. Measurement of active layer depth (ALD) of permafrost pale soil under the forest (natural) and arable land (anthropogenic) were carried out during 1990–2018 period. MAAT change for this period affected an early transition of negative temperatures to positive and a later establishment of negative temperatures. Additionally, a shortening of the winter season and an extension of the duration of days with positive temperatures was found. Since the permafrost has a significant impact on soil moisture and thermal regimes, the deepening of ALD plays a negative role for studied soils. An increase in the ALD can cause thawing of underground ice and lead to degradation of the ice-rich permafrost. This thaw process causes a change of the ecological balance and leads to the destruction of natural landscapes, sometimes with a complete or prolonged loss of their biological productivity. During this observation (1990–2018 period) the active layer of permafrost is characterized by high dynamics, depending on climatic parameters such as air temperature, as well as thickness and duration of snow cover. A significant increase in ALD of forest permafrost soils—by 80 cm and 65 cm—on arable land was measured during the observation period (28 years).
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28
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Jin X, Jin H, Wu X, Luo D, Yu S, Li X, He R, Wang Q, Knops JMH. Permafrost Degradation Leads to Biomass and Species Richness Decreases on the Northeastern Qinghai-Tibet Plateau. PLANTS 2020; 9:plants9111453. [PMID: 33126554 PMCID: PMC7692190 DOI: 10.3390/plants9111453] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 10/21/2020] [Accepted: 10/22/2020] [Indexed: 11/16/2022]
Abstract
Degradation of permafrost with a thin overlying active layer can greatly affect vegetation via changes in the soil water and nutrient regimes within the active layer, while little is known about the presence or absence of such effects in areas with a deep active layer. Here, we selected the northeastern Qinghai-Tibet Plateau as the study area. We examined the vegetation communities and biomass along an active layer thickness (ALT) gradient from 0.6 to 3.5 m. Our results showed that plant cover, below-ground biomass, species richness, and relative sedge cover declined with the deepening active layer, while the evenness, and relative forb cover showed a contrary trend. The vegetation indices and the dissimilarity of vegetation composition exhibited significant changes when the ALT was greater than 2.0 m. The vegetation indices (plant cover, below-ground biomass, evenness index, relative forb cover and relative sedge cover) were closely associated with soil water content, soil pH, texture and nutrient content. Soil water content played a key role in the ALT–vegetation relationship, especially at depths of 30–40 cm. Our results suggest that when the ALT is greater than 2.0 m, the presence of underlying permafrost still benefits vegetation growth via maintaining adequate soil water contents at 30–40 cm depth. Furthermore, the degradation of permafrost may lead to declines of vegetation cover and below-ground biomass with a shift in vegetation species.
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Affiliation(s)
- Xiaoying Jin
- Northeast-China Observatory and Research-Station of Permafrost Geo-Environment-Ministry of Education, Institute of Cold-Regions Science and Engineering, School of Civil Engineering, Northeast Forestry University, Harbin 150040, China; (X.J.); (D.L.); (S.Y.); (X.L.); (R.H.); (Q.W.)
- State Key Laboratory of Frozen Soils Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Huijun Jin
- Northeast-China Observatory and Research-Station of Permafrost Geo-Environment-Ministry of Education, Institute of Cold-Regions Science and Engineering, School of Civil Engineering, Northeast Forestry University, Harbin 150040, China; (X.J.); (D.L.); (S.Y.); (X.L.); (R.H.); (Q.W.)
- State Key Laboratory of Frozen Soils Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
- Correspondence:
| | - Xiaodong Wu
- Cryosphere Research Station on the Qinghai-Tibetan Plateau, State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China;
| | - Dongliang Luo
- Northeast-China Observatory and Research-Station of Permafrost Geo-Environment-Ministry of Education, Institute of Cold-Regions Science and Engineering, School of Civil Engineering, Northeast Forestry University, Harbin 150040, China; (X.J.); (D.L.); (S.Y.); (X.L.); (R.H.); (Q.W.)
| | - Sheng Yu
- Northeast-China Observatory and Research-Station of Permafrost Geo-Environment-Ministry of Education, Institute of Cold-Regions Science and Engineering, School of Civil Engineering, Northeast Forestry University, Harbin 150040, China; (X.J.); (D.L.); (S.Y.); (X.L.); (R.H.); (Q.W.)
| | - Xiaoying Li
- Northeast-China Observatory and Research-Station of Permafrost Geo-Environment-Ministry of Education, Institute of Cold-Regions Science and Engineering, School of Civil Engineering, Northeast Forestry University, Harbin 150040, China; (X.J.); (D.L.); (S.Y.); (X.L.); (R.H.); (Q.W.)
- State Key Laboratory of Frozen Soils Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
- School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - Ruixia He
- Northeast-China Observatory and Research-Station of Permafrost Geo-Environment-Ministry of Education, Institute of Cold-Regions Science and Engineering, School of Civil Engineering, Northeast Forestry University, Harbin 150040, China; (X.J.); (D.L.); (S.Y.); (X.L.); (R.H.); (Q.W.)
| | - Qingfeng Wang
- Northeast-China Observatory and Research-Station of Permafrost Geo-Environment-Ministry of Education, Institute of Cold-Regions Science and Engineering, School of Civil Engineering, Northeast Forestry University, Harbin 150040, China; (X.J.); (D.L.); (S.Y.); (X.L.); (R.H.); (Q.W.)
| | - Johannes M. H. Knops
- Department of Health and Environmental Sciences, Xi’an Jiaotong Liverpool University, Suzhou 215123, China;
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29
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Mosaicking Landsat and Sentinel-2 Data to Enhance LandTrendr Time Series Analysis in Northern High Latitude Permafrost Regions. REMOTE SENSING 2020. [DOI: 10.3390/rs12152471] [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
Permafrost is warming in the northern high latitudes, inducing highly dynamic thaw-related permafrost disturbances across the terrestrial Arctic. Monitoring and tracking of permafrost disturbances is important as they impact surrounding landscapes, ecosystems and infrastructure. Remote sensing provides the means to detect, map, and quantify these changes homogeneously across large regions and time scales. Existing Landsat-based algorithms assess different types of disturbances with similar spatiotemporal requirements. However, Landsat-based analyses are restricted in northern high latitudes due to the long repeat interval and frequent clouds, in particular at Arctic coastal sites. We therefore propose to combine Landsat and Sentinel-2 data for enhanced data coverage and present a combined annual mosaic workflow, expanding currently available algorithms, such as LandTrendr, to achieve more reliable time series analysis. We exemplary test the workflow for twelve sites across the northern high latitudes in Siberia. We assessed the number of images and cloud-free pixels, the spatial mosaic coverage and the mosaic quality with spectral comparisons. The number of available images increased steadily from 1999 to 2019 but especially from 2016 onward with the addition of Sentinel-2 images. Consequently, we have an increased number of cloud-free pixels even under challenging environmental conditions, which then serve as the input to the mosaicking process. In a comparison of annual mosaics, the Landsat+Sentinel-2 mosaics always fully covered the study areas (99.9–100 %), while Landsat-only mosaics contained data-gaps in the same years, only reaching coverage percentages of 27.2 %, 58.1 %, and 69.7 % for Sobo Sise, East Taymyr, and Kurungnakh in 2017, respectively. The spectral comparison of Landsat image, Sentinel-2 image, and Landsat+Sentinel-2 mosaic showed high correlation between the input images and mosaic bands (e.g., for Kurungnakh 0.91–0.97 between Landsat and Landsat+Sentinel-2 mosaic and 0.92–0.98 between Sentinel-2 and Landsat+Sentinel-2 mosaic) across all twelve study sites, testifying good quality mosaic results. Our results show that especially the results for northern, coastal areas was substantially improved with the Landsat+Sentinel-2 mosaics. By combining Landsat and Sentinel-2 data we accomplished to create reliably high spatial resolution input mosaics for time series analyses. Our approach allows to apply a high temporal continuous time series analysis to northern high latitude permafrost regions for the first time, overcoming substantial data gaps, and assess permafrost disturbance dynamics on an annual scale across large regions with algorithms such as LandTrendr by deriving the location, timing and progression of permafrost thaw disturbances.
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30
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Kou D, Yang G, Li F, Feng X, Zhang D, Mao C, Zhang Q, Peng Y, Ji C, Zhu Q, Fang Y, Liu X, Xu-Ri, Li S, Deng J, Zheng X, Fang J, Yang Y. Progressive nitrogen limitation across the Tibetan alpine permafrost region. Nat Commun 2020; 11:3331. [PMID: 32620773 PMCID: PMC7335038 DOI: 10.1038/s41467-020-17169-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 06/15/2020] [Indexed: 11/13/2022] Open
Abstract
The ecosystem carbon (C) balance in permafrost regions, which has a global significance in understanding the terrestrial C-climate feedback, is significantly regulated by nitrogen (N) dynamics. However, our knowledge on temporal changes in vegetation N limitation (i.e., the supply of N relative to plant N demand) in permafrost ecosystems is still limited. Based on the combination of isotopic observations derived from a re-sampling campaign along a ~3000 km transect and simulations obtained from a process-based biogeochemical model, here we detect changes in ecosystem N cycle across the Tibetan alpine permafrost region over the past decade. We find that vegetation N limitation becomes stronger despite the increased available N production. The enhanced N limitation on vegetation growth is driven by the joint effects of elevated plant N demand and gaseous N loss. These findings suggest that N would constrain the future trajectory of ecosystem C cycle in this alpine permafrost region.
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Affiliation(s)
- Dan Kou
- 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
- Biogeochemistry Research Group, Department of Biological and Environmental Sciences, University of Eastern Finland, Kuopio, 70210, Finland
- Earth, Atmospheric and Planetary Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - 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
| | - 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
| | - Xuehui Feng
- 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
| | - Chao Mao
- 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
| | - Qiwen 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
| | - Yunfeng Peng
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Chengjun Ji
- 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
| | - Qiuan Zhu
- College of Hydrology and Water Resources, Hohai University, Nanjing, 210098, China
| | - Yunting Fang
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Xueyan Liu
- School of Earth System Science, Tianjin University, Tianjin, 300072, China
| | - Xu-Ri
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Siqi Li
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Jia Deng
- Earth Systems Research Centre, Institute for the Study of Earth, Oceans and Space, University of New Hampshire, Durham, NH, 03824, USA
| | - Xunhua Zheng
- University of Chinese Academy of Sciences, Beijing, 100049, China
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Jingyun Fang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, 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
| | - 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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31
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Chisholm C, Becker MS, Pollard WH. The Importance of Incorporating Landscape Change for Predictions of Climate-Induced Plant Phenological Shifts. FRONTIERS IN PLANT SCIENCE 2020; 11:759. [PMID: 32670312 PMCID: PMC7329987 DOI: 10.3389/fpls.2020.00759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 05/13/2020] [Indexed: 06/11/2023]
Abstract
Warming in the high Arctic is occurring at the fastest rate on the planet, raising concerns over how this global change driver will influence plant community composition, the timing of vegetation phenological events, and the wildlife that rely on them. In this region, as much as 50% of near-surface permafrost is composed of thermally sensitive ground ice that when melted produces substantial changes in topography and microbiome conditions. We take advantage of natural variations in permafrost melt to conduct a space-for-time study on Ellesmere Island in northern Canada. We demonstrate that phenological timing can be delayed in thermokarst areas when compared to stable ground, and that this change is a function of shifting species composition in these vegetation communities as well as delayed timing within species. These findings suggest that a warming climate could result in an overall broadening of blooming and leafing windows at the landscape level when these delayed timings are taken into consideration with the projected advance of phenological timings in ice-poor areas. We emphasize that the impacts of geomorphic processes on key phenological drivers are essential for enhancing our understanding of community response to climate warming in the high Arctic, with implications for ecosystem functioning and trophic interactions.
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Affiliation(s)
- Chelsea Chisholm
- Center for Macroecology, Evolution and Climate, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - Michael S. Becker
- Center for Macroecology, Evolution and Climate, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
- Department of Geography, McGill University, Montreal, QC, Canada
| | - Wayne H. Pollard
- Department of Geography, McGill University, Montreal, QC, Canada
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32
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Li F, Peng Y, Chen L, Yang G, Abbott BW, Zhang D, Fang K, Wang G, Wang J, Yu J, Liu L, Zhang Q, Chen K, Mohammat A, Yang Y. Warming alters surface soil organic matter composition despite unchanged carbon stocks in a Tibetan permafrost ecosystem. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13489] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Fei Li
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
- University of Chinese Academy of Sciences Beijing China
- College of Life Science Taizhou University Taizhou China
| | - Yunfeng Peng
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
| | - Leiyi Chen
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
| | - Guibiao Yang
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
- University of Chinese Academy of Sciences Beijing China
| | - Benjamin W. Abbott
- Department of Plant and Wildlife Sciences Brigham Young University Provo UT USA
| | - Dianye Zhang
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
- University of Chinese Academy of Sciences Beijing China
| | - Kai Fang
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
- University of Chinese Academy of Sciences Beijing China
| | - Guanqin Wang
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
- University of Chinese Academy of Sciences Beijing China
| | - Jun Wang
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
- University of Chinese Academy of Sciences Beijing China
| | - Jianchun Yu
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
- University of Chinese Academy of Sciences Beijing China
| | - Li Liu
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
- University of Chinese Academy of Sciences Beijing China
| | - Qiwen Zhang
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
- University of Chinese Academy of Sciences Beijing China
| | - Kelong Chen
- College of Life and Geography Sciences Qinghai Normal University Xining China
| | - Anwar Mohammat
- Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Urumqi China
| | - Yuanhe Yang
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
- University of Chinese Academy of Sciences Beijing China
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The Effect of Nitrogen Content on Archaeal Diversity in an Arctic Lake Region. Microorganisms 2019; 7:microorganisms7110543. [PMID: 31717448 PMCID: PMC6920864 DOI: 10.3390/microorganisms7110543] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 11/04/2019] [Accepted: 11/07/2019] [Indexed: 11/24/2022] Open
Abstract
The function of Arctic soil ecosystems is crucially important for the global climate, and nitrogen (N) is the major limiting nutrient in these environments. This study assessed the effects of changes in nitrogen content on archaeal community diversity and composition in the Arctic lake area (London Island, Svalbard). A total of 16S rRNA genes were sequenced to investigate archaeal community composition. First, the soil samples and sediment samples were significantly different for the geochemical properties and archaeal community composition. Thaumarchaeota was an abundant phylum in the nine soil samples. Moreover, Euryarchaeota, Woesearchaeota, and Bathyarchaeota were significantly abundant phyla in the three sediment samples. Second, it was found that the surface runoff caused by the thawing of frozen soil and snow changed the geochemical properties of soils. Then, changes in geochemical properties affected the archaeal community composition in the soils. Moreover, a distance-based redundancy analysis revealed that NH4+–N (p < 0.05) and water content were the most significant factors that correlated with the archaeal community composition. Our study suggests that nitrogen content plays an important role in soil archaeal communities. Moreover, archaea play an important role in the carbon and nitrogen cycle in the Arctic lake area.
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A High-Resolution Airborne Color-Infrared Camera Water Mask for the NASA ABoVE Campaign. REMOTE SENSING 2019. [DOI: 10.3390/rs11182163] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The airborne AirSWOT instrument suite, consisting of an interferometric Ka-band synthetic aperture radar and color-infrared (CIR) camera, was deployed to northern North America in July and August 2017 as part of the NASA Arctic-Boreal Vulnerability Experiment (ABoVE). We present validated, open (i.e., vegetation-free) surface water masks produced from high-resolution (1 m), co-registered AirSWOT CIR imagery using a semi-automated, object-based water classification. The imagery and resulting high-resolution water masks are available as open-access datasets and support interpretation of AirSWOT radar and other coincident ABoVE image products, including LVIS, UAVSAR, AIRMOSS, AVIRIS-NG, and CFIS. These synergies offer promising potential for multi-sensor analysis of Arctic-Boreal surface water bodies. In total, 3167 km2 of open surface water were mapped from 23,380 km2 of flight lines spanning 23 degrees of latitude and broad environmental gradients. Detected water body sizes range from 0.00004 km2 (40 m2) to 15 km2. Power-law extrapolations are commonly used to estimate the abundance of small lakes from coarser resolution imagery, and our mapped water bodies followed power-law distributions, but only for water bodies greater than 0.34 (±0.13) km2 in area. For water bodies exceeding this size threshold, the coefficients of power-law fits vary for different Arctic-Boreal physiographic terrains (wetland, prairie pothole, lowland river valley, thermokarst, and Canadian Shield). Thus, direct mapping using high-resolution imagery remains the most accurate way to estimate the abundance of small surface water bodies. We conclude that empirical scaling relationships, useful for estimating total trace gas exchange and aquatic habitats on Arctic-Boreal landscapes, are uniquely enabled by high-resolution AirSWOT-like mappings and automated detection methods such as those developed here.
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Remote Sensing of Environmental Changes in Cold Regions: Methods, Achievements and Challenges. REMOTE SENSING 2019. [DOI: 10.3390/rs11161952] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Cold regions, including high-latitude and high-altitude landscapes, are experiencing profound environmental changes driven by global warming. With the advance of earth observation technology, remote sensing has become increasingly important for detecting, monitoring, and understanding environmental changes over vast and remote regions. This paper provides an overview of recent achievements, challenges, and opportunities for land remote sensing of cold regions by (a) summarizing the physical principles and methods in remote sensing of selected key variables related to ice, snow, permafrost, water bodies, and vegetation; (b) highlighting recent environmental nonstationarity occurring in the Arctic, Tibetan Plateau, and Antarctica as detected from satellite observations; (c) discussing the limits of available remote sensing data and approaches for regional monitoring; and (d) exploring new opportunities from next-generation satellite missions and emerging methods for accurate, timely, and multi-scale mapping of cold regions.
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36
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Comparing Spectral Characteristics of Landsat-8 and Sentinel-2 Same-Day Data for Arctic-Boreal Regions. REMOTE SENSING 2019. [DOI: 10.3390/rs11141730] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The Arctic-Boreal regions experience strong changes of air temperature and precipitation regimes, which affect the thermal state of the permafrost. This results in widespread permafrost-thaw disturbances, some unfolding slowly and over long periods, others occurring rapidly and abruptly. Despite optical remote sensing offering a variety of techniques to assess and monitor landscape changes, a persistent cloud cover decreases the amount of usable images considerably. However, combining data from multiple platforms promises to increase the number of images drastically. We therefore assess the comparability of Landsat-8 and Sentinel-2 imagery and the possibility to use both Landsat and Sentinel-2 images together in time series analyses, achieving a temporally-dense data coverage in Arctic-Boreal regions. We determined overlapping same-day acquisitions of Landsat-8 and Sentinel-2 images for three representative study sites in Eastern Siberia. We then compared the Landsat-8 and Sentinel-2 pixel-pairs, downscaled to 60 m, of corresponding bands and derived the ordinary least squares regression for every band combination. The acquired coefficients were used for spectral bandpass adjustment between the two sensors. The spectral band comparisons showed an overall good fit between Landsat-8 and Sentinel-2 images already. The ordinary least squares regression analyses underline the generally good spectral fit with intercept values between 0.0031 and 0.056 and slope values between 0.531 and 0.877. A spectral comparison after spectral bandpass adjustment of Sentinel-2 values to Landsat-8 shows a nearly perfect alignment between the same-day images. The spectral band adjustment succeeds in adjusting Sentinel-2 spectral values to Landsat-8 very well in Eastern Siberian Arctic-Boreal landscapes. After spectral adjustment, Landsat and Sentinel-2 data can be used to create temporally-dense time series and be applied to assess permafrost landscape changes in Eastern Siberia. Remaining differences between the sensors can be attributed to several factors including heterogeneous terrain, poor cloud and cloud shadow masking, and mixed pixels.
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Kwon MJ, Natali SM, Hicks Pries CE, Schuur EAG, Steinhof A, Crummer KG, Zimov N, Zimov SA, Heimann M, Kolle O, Göckede M. Drainage enhances modern soil carbon contribution but reduces old soil carbon contribution to ecosystem respiration in tundra ecosystems. GLOBAL CHANGE BIOLOGY 2019; 25:1315-1325. [PMID: 30681227 DOI: 10.1111/gcb.14578] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 01/15/2019] [Accepted: 01/17/2019] [Indexed: 05/06/2023]
Abstract
Warming temperatures are likely to accelerate permafrost thaw in the Arctic, potentially leading to the release of old carbon previously stored in deep frozen soil layers. Deeper thaw depths in combination with geomorphological changes due to the loss of ice structures in permafrost, may modify soil water distribution, creating wetter or drier soil conditions. Previous studies revealed higher ecosystem respiration rates under drier conditions, and this study investigated the cause of the increased ecosystem respiration rates using radiocarbon signatures of respired CO2 from two drying manipulation experiments: one in moist and the other in wet tundra. We demonstrate that higher contributions of CO2 from shallow soil layers (0-15 cm; modern soil carbon) drive the increased ecosystem respiration rates, while contributions from deeper soil (below 15 cm from surface and down to the permafrost table; old soil carbon) decreased. These changes can be attributed to more aerobic conditions in shallow soil layers, but also the soil temperature increases in shallow layers but decreases in deep layers, due to the altered thermal properties of organic soils. Decreased abundance of aerenchymatous plant species following drainage in wet tundra reduced old carbon release but increased aboveground plant biomass elevated contributions of autotrophic respiration to ecosystem respiration. The results of this study suggest that drier soils following drainage may accelerate decomposition of modern soil carbon in shallow layers but slow down decomposition of old soil carbon in deep layers, which may offset some of the old soil carbon loss from thawing permafrost.
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Affiliation(s)
- Min Jung Kwon
- Max Planck Institute for Biogeochemistry, Jena, Germany
- Korea Polar Research Institute, Incheon, South Korea
| | | | - Caitlin E Hicks Pries
- Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire
| | - Edward A G Schuur
- Center for Ecosystem Science and Society, and Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona
| | - Axel Steinhof
- Max Planck Institute for Biogeochemistry, Jena, Germany
| | - K Grace Crummer
- Department of Biology, University of Florida, Gainesville, Florida
| | - Nikita Zimov
- North-East Science Station, Pacific Institute for Geography, Far-Eastern Branch of Russian Academy of Science, Chersky, Republic of Sakha (Yakutia), Russia
| | - Sergey A Zimov
- North-East Science Station, Pacific Institute for Geography, Far-Eastern Branch of Russian Academy of Science, Chersky, Republic of Sakha (Yakutia), Russia
| | - Martin Heimann
- Max Planck Institute for Biogeochemistry, Jena, Germany
- Division of Atmospheric Sciences, Department of Physics, Helsinki University, Helsinki, Finland
| | - Olaf Kolle
- Max Planck Institute for Biogeochemistry, Jena, Germany
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Dynamics of microbial communities and CO 2 and CH 4 fluxes in the tundra ecosystems of the changing Arctic. J Microbiol 2019; 57:325-336. [PMID: 30656588 DOI: 10.1007/s12275-019-8661-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 12/20/2018] [Accepted: 12/24/2018] [Indexed: 10/27/2022]
Abstract
Arctic tundra ecosystems are rapidly changing due to the amplified effects of global warming within the northern high latitudes. Warming has the potential to increase the thawing of the permafrost and to change the landscape and its geochemical characteristics, as well as terrestrial biota. It is important to investigate microbial processes and community structures, since soil microorganisms play a significant role in decomposing soil organic carbon in the Arctic tundra. In addition, the feedback from tundra ecosystems to climate change, including the emission of greenhouse gases into the atmosphere, is substantially dependent on the compositional and functional changes in the soil microbiome. This article reviews the current state of knowledge of the soil microbiome and the two most abundant greenhouse gas (CO2 and CH4) emissions, and summarizes permafrost thaw-induced changes in the Arctic tundra. Furthermore, we discuss future directions in microbial ecological research coupled with its link to CO2 and CH4 emissions.
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