1
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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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2
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Wang Q, Peng X, Watanabe M, Batkhishig O, Okadera T, Saito Y. Carbon budget in permafrost and non-permafrost regions and its controlling factors in the grassland ecosystems of Mongolia. Glob Ecol Conserv 2023. [DOI: 10.1016/j.gecco.2023.e02373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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3
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Liu Z, Kimball JS, Ballantyne AP, Parazoo NC, Wang WJ, Bastos A, Madani N, Natali SM, Watts JD, Rogers BM, Ciais P, Yu K, Virkkala AM, Chevallier F, Peters W, Patra PK, Chandra N. Respiratory loss during late-growing season determines the net carbon dioxide sink in northern permafrost regions. Nat Commun 2022; 13:5626. [PMID: 36163194 PMCID: PMC9512808 DOI: 10.1038/s41467-022-33293-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 09/12/2022] [Indexed: 11/20/2022] Open
Abstract
Warming of northern high latitude regions (NHL, > 50 °N) has increased both photosynthesis and respiration which results in considerable uncertainty regarding the net carbon dioxide (CO2) balance of NHL ecosystems. Using estimates constrained from atmospheric observations from 1980 to 2017, we find that the increasing trends of net CO2 uptake in the early-growing season are of similar magnitude across the tree cover gradient in the NHL. However, the trend of respiratory CO2 loss during late-growing season increases significantly with increasing tree cover, offsetting a larger fraction of photosynthetic CO2 uptake, and thus resulting in a slower rate of increasing annual net CO2 uptake in areas with higher tree cover, especially in central and southern boreal forest regions. The magnitude of this seasonal compensation effect explains the difference in net CO2 uptake trends along the NHL vegetation- permafrost gradient. Such seasonal compensation dynamics are not captured by dynamic global vegetation models, which simulate weaker respiration control on carbon exchange during the late-growing season, and thus calls into question projections of increasing net CO2 uptake as high latitude ecosystems respond to warming climate conditions. The northern high latitude permafrost region has been an important contributor to the carbon sink since the 1980s. A new study finds that as tree cover increases, respiratory CO2 loss during late-growing season offsets photosynthetic CO2 uptake and leads to a slower rate of increasing annual net CO2 uptake.
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Affiliation(s)
- Zhihua Liu
- Numerical Terradynamic Simulation Group, WA Franke College of Forestry and Conservation, University of Montana, Missoula, MT, USA. .,CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning, China.
| | - John S Kimball
- Numerical Terradynamic Simulation Group, WA Franke College of Forestry and Conservation, University of Montana, Missoula, MT, USA. .,Department of Ecosystem and Conservation Sciences, University of Montana, Missoula, MT, USA.
| | - Ashley P Ballantyne
- Department of Ecosystem and Conservation Sciences, University of Montana, Missoula, MT, USA. .,Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France.
| | - Nicholas C Parazoo
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Wen J Wang
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, Changchun, Jilin, China.
| | - Ana Bastos
- Max Planck Institute for Biogeochemistry, Department of Biogeochemical Integration, Jena, Germany
| | - Nima Madani
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | | | | | | | - Philippe Ciais
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Kailiang Yu
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France
| | | | - Frederic Chevallier
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Wouter Peters
- Meteorology and Air Quality Group, Wageningen University and Research, Wageningen, the Netherlands.,University, Centre for Isotope Research, Groningen, the Netherlands
| | - Prabir K Patra
- Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, Japan
| | - Naveen Chandra
- Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, Japan
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4
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Li Q, Liu Y, Kou D, Peng Y, Yang Y. Substantial non-growing season carbon dioxide loss across Tibetan alpine permafrost region. GLOBAL CHANGE BIOLOGY 2022; 28:5200-5210. [PMID: 35748703 DOI: 10.1111/gcb.16315] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 05/09/2022] [Accepted: 06/06/2022] [Indexed: 06/15/2023]
Abstract
One of the major uncertainties for projecting permafrost carbon (C)-climate feedback is a poor representation of the non-growing season carbon dioxide (CO2 ) emissions under a changing climate. Here, combining in situ field observations, regional synthesis and a random forest model, we assessed contemporary and future soil respired CO2 (i.e., soil respiration, Rs ) across the Tibetan alpine permafrost region, which has received much less attention compared with the Arctic permafrost domain. We estimated the regional mean Rs of 229.8, 72.9 and 302.7 g C m-2 year-1 during growing season, non-growing season and the entire year, respectively; corresponding to the contemporary losses of 296.9, 94.3 and 391.2 Tg C year-1 from this high-altitude permafrost-affected area. The non-growing season Rs accounted for a quarter of the annual soil CO2 efflux. Different from the prevailing view that temperature is the most limiting factor for cold-period CO2 release in Arctic permafrost ecosystems, precipitation determined the spatial pattern of non-growing season Rs on the Tibetan Plateau. Using the key predictors, model extrapolation demonstrated additional losses of 38.8 and 74.5 Tg C from the non-growing season for a moderate mitigation scenario and a business-as-usual emissions scenario, respectively. These results provide a baseline for non-growing season CO2 emissions from high-altitude permafrost areas and help for accurate projection of permafrost C-climate feedback.
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Affiliation(s)
- Qinlu 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
| | - Yang Liu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- College of Resources and Environmental Sciences/Key Laboratory of Farmland Eco-Environment of Hebei, Hebei Agricultural University, Baoding, China
| | - Dan Kou
- Biogeochemistry Research Group, Department of Biological and Environmental Sciences, University of Eastern Finland, Kuopio, Finland
| | - Yunfeng Peng
- 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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5
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Euskirchen ES, Serbin SP, Carman TB, Fraterrigo JM, Genet H, Iversen CM, Salmon V, McGuire AD. Assessing dynamic vegetation model parameter uncertainty across Alaskan arctic tundra plant communities. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2022; 32:e2499. [PMID: 34787932 PMCID: PMC9285828 DOI: 10.1002/eap.2499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 06/22/2021] [Accepted: 07/20/2021] [Indexed: 06/13/2023]
Abstract
As the Arctic region moves into uncharted territory under a warming climate, it is important to refine the terrestrial biosphere models (TBMs) that help us understand and predict change. One fundamental uncertainty in TBMs relates to model parameters, configuration variables internal to the model whose value can be estimated from data. We incorporate a version of the Terrestrial Ecosystem Model (TEM) developed for arctic ecosystems into the Predictive Ecosystem Analyzer (PEcAn) framework. PEcAn treats model parameters as probability distributions, estimates parameters based on a synthesis of available field data, and then quantifies both model sensitivity and uncertainty to a given parameter or suite of parameters. We examined how variation in 21 parameters in the equation for gross primary production influenced model sensitivity and uncertainty in terms of two carbon fluxes (net primary productivity and heterotrophic respiration) and two carbon (C) pools (vegetation C and soil C). We set up different parameterizations of TEM across a range of tundra types (tussock tundra, heath tundra, wet sedge tundra, and shrub tundra) in northern Alaska, along a latitudinal transect extending from the coastal plain near Utqiaġvik to the southern foothills of the Brooks Range, to the Seward Peninsula. TEM was most sensitive to parameters related to the temperature regulation of photosynthesis. Model uncertainty was mostly due to parameters related to leaf area, temperature regulation of photosynthesis, and the stomatal responses to ambient light conditions. Our analysis also showed that sensitivity and uncertainty to a given parameter varied spatially. At some sites, model sensitivity and uncertainty tended to be connected to a wider range of parameters, underlining the importance of assessing tundra community processes across environmental gradients or geographic locations. Generally, across sites, the flux of net primary productivity (NPP) and pool of vegetation C had about equal uncertainty, while heterotrophic respiration had higher uncertainty than the pool of soil C. Our study illustrates the complexity inherent in evaluating parameter uncertainty across highly heterogeneous arctic tundra plant communities. It also provides a framework for iteratively testing how newly collected field data related to key parameters may result in more effective forecasting of Arctic change.
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Affiliation(s)
| | - Shawn P. Serbin
- Terrestrial Ecosystem Science & Technology GroupEnvironmental Sciences DepartmentBrookhaven National LaboratoryUptonNew York11973USA
| | - Tobey B. Carman
- Institute of Arctic BiologyUniversity of Alaska FairbanksFairbanksAlaska99775USA
| | - Jennifer M. Fraterrigo
- Department of Natural Resources and Environmental SciencesUniversity of Illinois at Urbana‐ChampaignUrbanaIllinois61801USA
| | - Hélène Genet
- Institute of Arctic BiologyUniversity of Alaska FairbanksFairbanksAlaska99775USA
| | - Colleen M. Iversen
- Environmental Sciences Division and Climate Change Science InstituteOak Ridge National LaboratoryOak RidgeTennessee37831USA
| | - Verity Salmon
- Environmental Sciences Division and Climate Change Science InstituteOak Ridge National LaboratoryOak RidgeTennessee37831USA
| | - A. David McGuire
- Institute of Arctic BiologyUniversity of Alaska FairbanksFairbanksAlaska99775USA
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6
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Wu L, Yang F, Feng J, Tao X, Qi Q, Wang C, Schuur EAG, Bracho R, Huang Y, Cole JR, Tiedje JM, Zhou J. Permafrost thaw with warming reduces microbial metabolic capacities in subsurface soils. Mol Ecol 2021; 31:1403-1415. [PMID: 34878672 DOI: 10.1111/mec.16319] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/04/2021] [Accepted: 12/01/2021] [Indexed: 01/27/2023]
Abstract
Microorganisms are major constituents of the total biomass in permafrost regions, whose underlain soils are frozen for at least two consecutive years. To understand potential microbial responses to climate change, here we examined microbial community compositions and functional capacities across four soil depths in an Alaska tundra site. We showed that a 5-year warming treatment increased soil thaw depth by 25.7% (p = .011) within the deep organic layer (15-25 cm). Concurrently, warming reduced 37% of bacterial abundance and 64% of fungal abundances in the deep organic layer, while it did not affect microbial abundance in other soil layers (i.e., 0-5, 5-15, and 45-55 cm). Warming treatment altered fungal community composition and microbial functional structure (p < .050), but not bacterial community composition. Using a functional gene array, we found that the relative abundances of a variety of carbon (C)-decomposing, iron-reducing, and sulphate-reducing genes in the deep organic layer were decreased, which was not observed by the shotgun sequencing-based metagenomics analysis of those samples. To explain the reduced metabolic capacities, we found that warming treatment elicited higher deterministic environmental filtering, which could be linked to water-saturated time, soil moisture, and soil thaw duration. In contrast, plant factors showed little influence on microbial communities in subsurface soils below 15 cm, despite a 25.2% higher (p < .05) aboveground plant biomass by warming treatment. Collectively, we demonstrate that microbial metabolic capacities in subsurface soils are reduced, probably arising from enhanced thaw by warming.
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Affiliation(s)
- Linwei Wu
- Department of Microbiology and Plant Biology, School of Civil Engineering and Environmental Sciences, Institute for Environmental Genomics, University of Oklahoma, Norman, Oklahoma, USA
| | - Felix Yang
- Department of Microbiology and Plant Biology, School of Civil Engineering and Environmental Sciences, Institute for Environmental Genomics, University of Oklahoma, Norman, Oklahoma, USA
| | - Jiajie Feng
- Department of Microbiology and Plant Biology, School of Civil Engineering and Environmental Sciences, Institute for Environmental Genomics, University of Oklahoma, Norman, Oklahoma, USA
| | - Xuanyu Tao
- Department of Microbiology and Plant Biology, School of Civil Engineering and Environmental Sciences, Institute for Environmental Genomics, University of Oklahoma, Norman, Oklahoma, USA
| | - Qi Qi
- School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing, China
| | - Cong Wang
- Department of Microbiology and Plant Biology, School of Civil Engineering and Environmental Sciences, Institute for Environmental Genomics, University of Oklahoma, Norman, Oklahoma, USA
| | - Edward A G Schuur
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
| | - Rosvel Bracho
- Department of Biology, School of Forest Resources and Conservation, University of Florida, Gainesville, Florida, USA
| | - Yi Huang
- College of Environmental Science and Engineering, State Key Joint Laboratory of Environmental Simulation and Pollution Control, Peking University, Beijing, China
| | - James R Cole
- Center for Microbial Ecology, Michigan State University, East Lansing, Michigan, USA
| | - James M Tiedje
- Center for Microbial Ecology, Michigan State University, East Lansing, Michigan, USA
| | - Jizhong Zhou
- Department of Microbiology and Plant Biology, School of Civil Engineering and Environmental Sciences, Institute for Environmental Genomics, University of Oklahoma, Norman, Oklahoma, USA.,Earth and Environmental Sciences, Lawrence Berkeley National Laboratory, Berkeley, California, USA
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7
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Virkkala AM, Aalto J, Rogers BM, Tagesson T, Treat CC, Natali SM, Watts JD, Potter S, Lehtonen A, Mauritz M, Schuur EAG, Kochendorfer J, Zona D, Oechel W, Kobayashi H, Humphreys E, Goeckede M, Iwata H, Lafleur PM, Euskirchen ES, Bokhorst S, Marushchak M, Martikainen PJ, Elberling B, Voigt C, Biasi C, Sonnentag O, Parmentier FJW, Ueyama M, Celis G, St Louis VL, Emmerton CA, Peichl M, Chi J, Järveoja J, Nilsson MB, Oberbauer SF, Torn MS, Park SJ, Dolman H, Mammarella I, Chae N, Poyatos R, López-Blanco E, Christensen TR, Kwon MJ, Sachs T, Holl D, Luoto M. Statistical upscaling of ecosystem CO 2 fluxes across the terrestrial tundra and boreal domain: Regional patterns and uncertainties. GLOBAL CHANGE BIOLOGY 2021; 27:4040-4059. [PMID: 33913236 DOI: 10.1111/gcb.15659] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 03/05/2021] [Indexed: 06/12/2023]
Abstract
The regional variability in tundra and boreal carbon dioxide (CO2 ) fluxes can be high, complicating efforts to quantify sink-source patterns across the entire region. Statistical models are increasingly used to predict (i.e., upscale) CO2 fluxes across large spatial domains, but the reliability of different modeling techniques, each with different specifications and assumptions, has not been assessed in detail. Here, we compile eddy covariance and chamber measurements of annual and growing season CO2 fluxes of gross primary productivity (GPP), ecosystem respiration (ER), and net ecosystem exchange (NEE) during 1990-2015 from 148 terrestrial high-latitude (i.e., tundra and boreal) sites to analyze the spatial patterns and drivers of CO2 fluxes and test the accuracy and uncertainty of different statistical models. CO2 fluxes were upscaled at relatively high spatial resolution (1 km2 ) across the high-latitude region using five commonly used statistical models and their ensemble, that is, the median of all five models, using climatic, vegetation, and soil predictors. We found the performance of machine learning and ensemble predictions to outperform traditional regression methods. We also found the predictive performance of NEE-focused models to be low, relative to models predicting GPP and ER. Our data compilation and ensemble predictions showed that CO2 sink strength was larger in the boreal biome (observed and predicted average annual NEE -46 and -29 g C m-2 yr-1 , respectively) compared to tundra (average annual NEE +10 and -2 g C m-2 yr-1 ). This pattern was associated with large spatial variability, reflecting local heterogeneity in soil organic carbon stocks, climate, and vegetation productivity. The terrestrial ecosystem CO2 budget, estimated using the annual NEE ensemble prediction, suggests the high-latitude region was on average an annual CO2 sink during 1990-2015, although uncertainty remains high.
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Affiliation(s)
- Anna-Maria Virkkala
- Department of Geosciences and Geography, Faculty of Science, University of Helsinki, Helsinki, Finland
- Woodwell Climate Research Center, Falmouth, MA, USA
| | - Juha Aalto
- Department of Geosciences and Geography, Faculty of Science, University of Helsinki, Helsinki, Finland
- Weather and Climate Change Impact Research, Finnish Meteorological Institute, Helsinki, Finland
| | | | - Torbern Tagesson
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
- Department of Geosciences and Natural Resource Management, Copenhagen University, Copenhagen, Denmark
| | - Claire C Treat
- Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Potsdam, Germany
| | | | | | | | | | | | - Edward A G Schuur
- Center for Ecosystem Science and Society, Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - John Kochendorfer
- Atmosperic Turbulence and Diffusion Division of NOAA's Air Resources Laboratory, Oak Ridge, TN, USA
| | - Donatella Zona
- San Diego State University, San Diego, CA, USA
- University of Sheffield, Sheffield, UK
| | - Walter Oechel
- San Diego State University, San Diego, CA, USA
- University of Exeter, Exeter, UK
| | - Hideki Kobayashi
- Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokoama, Japan
| | | | - Mathias Goeckede
- Dept. Biogeochemical Signals, Max Planck Institute for Biogeochemistry, Jena, Germany
| | - Hiroki Iwata
- Department of Environmental Science, Shinshu University, Matsumoto, Japan
| | - Peter M Lafleur
- School of the Environment, Trent University, Peterborough, ON, Canada
| | | | - Stef Bokhorst
- Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Maija Marushchak
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
| | - Pertti J Martikainen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
| | - Bo Elberling
- Center for Permafrost, Department of Geoscience and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
| | - Carolina Voigt
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
- Département de géographie, Université de Montréal, Montréal, QC, Canada
| | - Christina Biasi
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
| | - Oliver Sonnentag
- Département de géographie, Université de Montréal, Montréal, QC, Canada
| | - Frans-Jan W Parmentier
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
- Centre for Biogeochemistry in the Anthropocene, Department of Geosciences, University of Oslo, Oslo, Norway
| | - Masahito Ueyama
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Japan
| | - Gerardo Celis
- Agronomy Department, University of Florida, Gainesville, FL, USA
| | - Vincent L St Louis
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Craig A Emmerton
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Matthias Peichl
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Jinshu Chi
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Järvi Järveoja
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Mats B Nilsson
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Steven F Oberbauer
- Department of Biological Sciences, Florida International University, Miami, FL, USA
| | | | - Sang-Jong Park
- Division of Atmospheric Sciences, Korea Polar Research Institute, Incheon, Republic of Korea
| | - Han Dolman
- Department of Earth Sciences, Free University Amsterdam, Amsterdam, the Netherlands
| | - Ivan Mammarella
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland
| | - Namyi Chae
- Institute of Life Science and Natural Resources, Korea University, Seoul, Republic of Korea
| | - Rafael Poyatos
- CREAF, Catalonia, Spain
- Universitat Autònoma de Barcelona, Catalonia, Spain
| | - Efrén López-Blanco
- Department of Environment and Minerals, Greenland Institute of Natural Resources, Nuuk, Greenland
- Department of Bioscience, Arctic Research Center, Aarhus University, Roskilde, Denmark
| | | | - Min Jung Kwon
- Laboratoire des Sciences du Climat et de l'Environnement, Gif-sur-Yvette, France
- Division of Life Sciences, Korea Polar Research Institute, Incheon, Republic of Korea
| | - Torsten Sachs
- GFZ German Research Centre for Geosciences, Potsdam, Germany
| | - David Holl
- Center for Earth System Research and Sustainability (CEN), University of Hamburg, Hamburg, Germany
| | - Miska Luoto
- Department of Geosciences and Geography, Faculty of Science, University of Helsinki, Helsinki, Finland
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8
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Wei D, Qi Y, Ma Y, Wang X, Ma W, Gao T, Huang L, Zhao H, Zhang J, Wang X. Plant uptake of CO 2 outpaces losses from permafrost and plant respiration on the Tibetan Plateau. Proc Natl Acad Sci U S A 2021; 118:e2015283118. [PMID: 34373324 PMCID: PMC8379928 DOI: 10.1073/pnas.2015283118] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
High-latitude and high-altitude regions contain vast stores of permafrost carbon. Climate warming may result in the release of CO2 from both the thawing of permafrost and accelerated autotrophic respiration, but it may also increase the fixation of CO2 by plants, which could relieve or even offset the CO2 losses. The Tibetan Plateau contains the largest area of alpine permafrost on Earth. However, the current status of the net CO2 balance and feedbacks to warming remain unclear, given that the region has recently experienced an atmospheric warming rate of over 0.3 °C decade-1 We examined 32 eddy covariance sites and found an unexpected net CO2 sink during 2002 to 2020 (26 of the sites yielded a net CO2 sink) that was four times the amount previously estimated. The CO2 sink peaked at an altitude of roughly 4,000 m, with the sink at lower and higher altitudes limited by a low carbon use efficiency and a cold, dry climate, respectively. The fixation of CO2 in summer is more dependent on temperature than the loss of CO2 than it is in the winter months, especially at higher altitudes. Consistently, 16 manipulative experiments and 18 model simulations showed that the fixation of CO2 by plants will outpace the loss of CO2 under a wetting-warming climate until the 2090s (178 to 318 Tg C y-1). We therefore suggest that there is a plant-dominated negative feedback to climate warming on the Tibetan Plateau.
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Affiliation(s)
- Da Wei
- Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China
| | - Yahui Qi
- Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yaoming Ma
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
- Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Xufeng Wang
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Weiqiang Ma
- Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Tanguang Gao
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China
| | - Lin Huang
- Institute of Geophysical Science and Natural Resource Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Hui Zhao
- Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China
| | - Jianxin Zhang
- Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaodan Wang
- Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China;
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9
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Lin X, Rogers BM, Sweeney C, Chevallier F, Arshinov M, Dlugokencky E, Machida T, Sasakawa M, Tans P, Keppel-Aleks G. Siberian and temperate ecosystems shape Northern Hemisphere atmospheric CO 2 seasonal amplification. Proc Natl Acad Sci U S A 2020; 117:21079-21087. [PMID: 32817563 PMCID: PMC7474631 DOI: 10.1073/pnas.1914135117] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
The amplitude of the atmospheric CO2 seasonal cycle has increased by 30 to 50% in the Northern Hemisphere (NH) since the 1960s, suggesting widespread ecological changes in the northern extratropics. However, substantial uncertainty remains in the continental and regional drivers of this prominent amplitude increase. Here we present a quantitative regional attribution of CO2 seasonal amplification over the past 4 decades, using a tagged atmospheric transport model prescribed with observationally constrained fluxes. We find that seasonal flux changes in Siberian and temperate ecosystems together shape the observed amplitude increases in the NH. At the surface of northern high latitudes, enhanced seasonal carbon exchange in Siberia is the dominant contributor (followed by temperate ecosystems). Arctic-boreal North America shows much smaller changes in flux seasonality and has only localized impacts. These continental contrasts, based on an atmospheric approach, corroborate heterogeneous vegetation greening and browning trends from field and remote-sensing observations, providing independent evidence for regionally divergent ecological responses and carbon dynamics to global change drivers. Over surface midlatitudes and throughout the midtroposphere, increased seasonal carbon exchange in temperate ecosystems is the dominant contributor to CO2 amplification, albeit with considerable contributions from Siberia. Representing the mechanisms that control the high-latitude asymmetry in flux amplification found in this study should be an important goal for mechanistic land surface models moving forward.
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Affiliation(s)
- Xin Lin
- Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI 48109;
| | | | - Colm Sweeney
- Global Monitoring Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO 80305
| | - Frédéric Chevallier
- Laboratoire des Sciences du Climat et de l'Environnement/Institut Pierre Simon Laplace, Commissariat à l'Énergie Atomique et aux Énergies Alternatives-CNRS-Université de Versailles Saint-Quentin-en-Yvelines, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
| | - Mikhail Arshinov
- Vladimir Evseevich Zuev Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, Tomsk 634055, Russia
| | - Edward Dlugokencky
- Global Monitoring Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO 80305
| | - Toshinobu Machida
- Center for Global Environmental Research, National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506, Japan
| | - Motoki Sasakawa
- Center for Global Environmental Research, National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506, Japan
| | - Pieter Tans
- Global Monitoring Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO 80305
| | - Gretchen Keppel-Aleks
- Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI 48109;
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10
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Insect herbivory dampens Subarctic birch forest C sink response to warming. Nat Commun 2020; 11:2529. [PMID: 32439857 PMCID: PMC7242322 DOI: 10.1038/s41467-020-16404-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Accepted: 04/27/2020] [Indexed: 11/21/2022] Open
Abstract
Climate warming is anticipated to make high latitude ecosystems stronger C sinks through increasing plant production. This effect might, however, be dampened by insect herbivores whose damage to plants at their background, non-outbreak densities may more than double under climate warming. Here, using an open-air warming experiment among Subarctic birch forest field layer vegetation, supplemented with birch plantlets, we show that a 2.3 °C air and 1.2 °C soil temperature increase can advance the growing season by 1–4 days, enhance soil N availability, leaf chlorophyll concentrations and plant growth up to 400%, 160% and 50% respectively, and lead up to 122% greater ecosystem CO2 uptake potential. However, comparable positive effects are also found when insect herbivory is reduced, and the effect of warming on C sink potential is intensified under reduced herbivory. Our results confirm the expected warming-induced increase in high latitude plant growth and CO2 uptake, but also reveal that herbivorous insects may significantly dampen the strengthening of the CO2 sink under climate warming. Warming is expected to increase C sink capacity in high-latitude ecosystems, but plant-herbivore interactions could moderate or offset this effect. Here, Silfver and colleagues test individual and interactive effects of warming and insect herbivory in a field experiment in Subarctic forest, showing that even low intensity insect herbivory strongly reduces C sink potential.
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11
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Ylänne H, Kaarlejärvi E, Väisänen M, Männistö MK, Ahonen SHK, Olofsson J, Stark S. Removal of grazers alters the response of tundra soil carbon to warming and enhanced nitrogen availability. ECOL MONOGR 2019. [DOI: 10.1002/ecm.1396] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Henni Ylänne
- Arctic Center University of Lapland P.O. Box 122 Rovaniemi FI‐96101 Finland
- Department of Ecology and Genetics University of Oulu P.O. Box 3000 Oulu FI‐90100 Finland
| | - Elina Kaarlejärvi
- Department of Ecology and Environmental Sciences Umeå University Umeå SE‐90187 Sweden
- Department of Biology Vrije Universiteit Brussel (VUB) Pleinlaan 2 Brussel B‐1050 Belgium
| | - Maria Väisänen
- Arctic Center University of Lapland P.O. Box 122 Rovaniemi FI‐96101 Finland
| | - Minna K. Männistö
- Natural Resources Institute Finland (Luke) Eteläranta 55 Rovaniemi FI‐96300 Finland
| | - Saija H. K. Ahonen
- Department of Ecology and Genetics University of Oulu P.O. Box 3000 Oulu FI‐90100 Finland
| | - Johan Olofsson
- Department of Ecology and Environmental Sciences Umeå University Umeå SE‐90187 Sweden
| | - Sari Stark
- Arctic Center University of Lapland P.O. Box 122 Rovaniemi FI‐96101 Finland
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12
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Gadkari PS, McGuinness LR, Männistö MK, Kerkhof LJ, Häggblom MM. Arctic tundra soil bacterial communities active at subzero temperatures detected by stable isotope probing. FEMS Microbiol Ecol 2019; 96:5645228. [DOI: 10.1093/femsec/fiz192] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 11/26/2019] [Indexed: 12/14/2022] Open
Abstract
ABSTRACT
Arctic soils store vast amounts of carbon and are subject to intense climate change. While the effects of thaw on the composition and activities of Arctic tundra microorganisms has been examined extensively, little is known about the consequences of temperature fluctuations within the subzero range in seasonally frozen or permafrost soils. This study identified tundra soil bacteria active at subzero temperatures using stable isotope probing (SIP). Soils from Kilpisjärvi, Finland, were amended with 13C-cellobiose and incubated at 0, −4 and −16°C for up to 40 weeks. 16S rRNA gene sequence analysis of 13C-labelled DNA revealed distinct subzero-active bacterial taxa. The SIP experiments demonstrated that diverse bacteria, including members of Candidatus Saccharibacteria, Melioribacteraceae, Verrucomicrobiaceae, Burkholderiaceae, Acetobacteraceae, Armatimonadaceae and Planctomycetaceae, were capable of synthesising 13C-DNA at subzero temperatures. Differences in subzero temperature optima were observed, for example, with members of Oxalobacteraceae and Rhizobiaceae found to be more active at 0°C than at −4°C or −16°C, whereas Melioribacteriaceae were active at all subzero temperatures tested. Phylogeny of 13C-labelled 16S rRNA genes from the Melioribacteriaceae, Verrucomicrobiaceae and Candidatus Saccharibacteria suggested that these taxa formed subzero-active clusters closely related to members from other cryo-environments. This study demonstrates that subzero temperatures impact active bacterial community composition and activity, which may influence biogeochemical cycles.
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Affiliation(s)
- Preshita S Gadkari
- School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick NJ 08901, USA
| | - Lora R McGuinness
- Department of Marine and Coastal Sciences, School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - Minna K Männistö
- Natural Resources Institute Finland, P.O. Box 16, FI-96301 Rovaniemi, Finland
| | - Lee J Kerkhof
- Department of Marine and Coastal Sciences, School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - Max M Häggblom
- School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick NJ 08901, USA
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13
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Natali SM, Watts JD, Rogers BM, Potter S, Ludwig SM, Selbmann AK, Sullivan PF, Abbott BW, Arndt KA, Birch L, Björkman MP, Bloom AA, Celis G, Christensen TR, Christiansen CT, Commane R, Cooper EJ, Crill P, Czimczik C, Davydov S, Du J, Egan JE, Elberling B, Euskirchen ES, Friborg T, Genet H, Göckede M, Goodrich JP, Grogan P, Helbig M, Jafarov EE, Jastrow JD, Kalhori AAM, Kim Y, Kimball J, Kutzbach L, Lara MJ, Larsen KS, Lee BY, Liu Z, Loranty MM, Lund M, Lupascu M, Madani N, Malhotra A, Matamala R, McFarland J, McGuire AD, Michelsen A, Minions C, Oechel WC, Olefeldt D, Parmentier FJW, Pirk N, Poulter B, Quinton W, Rezanezhad F, Risk D, Sachs T, Schaefer K, Schmidt NM, Schuur EA, Semenchuk PR, Shaver G, Sonnentag O, Starr G, Treat CC, Waldrop MP, Wang Y, Welker J, Wille C, Xu X, Zhang Z, Zhuang Q, Zona D. Large loss of CO 2 in winter observed across the northern permafrost region. NATURE CLIMATE CHANGE 2019; 9:852-857. [PMID: 35069807 PMCID: PMC8781060 DOI: 10.1038/s41558-019-0592-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 09/04/2019] [Indexed: 05/18/2023]
Abstract
Recent warming in the Arctic, which has been amplified during the winter1-3, greatly enhances microbial decomposition of soil organic matter and subsequent release of carbon dioxide (CO2)4. However, the amount of CO2 released in winter is highly uncertain and has not been well represented by ecosystem models or by empirically-based estimates5,6. Here we synthesize regional in situ observations of CO2 flux from arctic and boreal soils to assess current and future winter carbon losses from the northern permafrost domain. We estimate a contemporary loss of 1662 Tg C yr-1 from the permafrost region during the winter season (October through April). This loss is greater than the average growing season carbon uptake for this region estimated from process models (-1032 Tg C yr-1). Extending model predictions to warmer conditions in 2100 indicates that winter CO2 emissions will increase 17% under a moderate mitigation scenario-Representative Concentration Pathway (RCP) 4.5-and 41% under business-as-usual emissions scenario-RCP 8.5. Our results provide a new baseline for winter CO2 emissions from northern terrestrial regions and indicate that enhanced soil CO2 loss due to winter warming may offset growing season carbon uptake under future climatic conditions.
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Affiliation(s)
- Susan. M. Natali
- Woods Hole Research Center, Falmouth, MA 02540, USA
- Correspondence to:
| | | | | | | | | | | | - Patrick F. Sullivan
- Environment and Natural Resources Institute, University of Alaska, Anchorage, AK 99508. USA
| | - Benjamin W. Abbott
- Brigham Young University, Department of Plant and Wildlife Sciences, Provo, UT 84602, USA
| | - Kyle A. Arndt
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
| | - Leah Birch
- Woods Hole Research Center, Falmouth, MA 02540, USA
| | - Mats P. Björkman
- Department of Earth Sciences, University of Gothenburg, PO Box 460, SE-405 30 Göteborg, Sweden
| | - A. Anthony Bloom
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Gerardo Celis
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ 86001, USA
| | - Torben R. Christensen
- Department of Bioscience, Arctic Research Centre, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | | | - Roisin Commane
- Dept. of Earth & Environmental Sciences of Lamont-Doherty Earth Observatory at Columbia University, Palisades, NY 10964, USA
| | - Elisabeth J. Cooper
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT. The Arctic University of Norway, N9037 Tromsø, Norway
| | - Patrick Crill
- Dept. of Geological Sciences and Bolin Centre for Climate Research, Stockholm University, Sweden
| | - Claudia Czimczik
- Earth System Science, University of California, Irvine, CA 92697, USA
| | - Sergey Davydov
- Northeast Science Station, Pacific Geographical Institute, Cherskii, Russia
| | - Jinyang Du
- Numerical Terradynamic Simulation Group, W.A. Franke College of Forestry & Conservation, University of Montana, Missoula, MT 59812, USA
| | - Jocelyn E. Egan
- Department of Earth Sciences, Dalhousie University, Halifax, NS, Canada
| | - Bo Elberling
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen, Denmark
| | - Eugenie S. Euskirchen
- University of Alaska Fairbanks, Institute of Arctic Biology, Fairbanks, AK 99775, USA
| | - Thomas Friborg
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark
| | - Hélène Genet
- University of Alaska Fairbanks, Institute of Arctic Biology, Fairbanks, AK 99775, USA
| | | | - Jordan P. Goodrich
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
- Scripps Institution of Oceanography, UCSD, La Jolla, CA 92037, USA
| | - Paul Grogan
- Department of Biology, Queen’s University, Kingston, ON, Canada
| | - Manuel Helbig
- McMaster University, School of Geography and Earth Sciences, Hamilton, ON, L8S 4K1
- Université de Montréal, Département de géographie & Centre d’études nordiques, 520 chemin de la Côte Sainte Catherine, Montréal, QC H2V 2B8
| | - Elchin E. Jafarov
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Julie D. Jastrow
- Environmental Science Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Aram A. M. Kalhori
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
| | - Yongwon Kim
- International Arctic Research Center, University of Alaska Fairbanks, AK 99775, USA
| | - John Kimball
- Numerical Terradynamic Simulation Group, W.A. Franke College of Forestry & Conservation, University of Montana, Missoula, MT 59812, USA
| | - Lars Kutzbach
- Institute of Soil Science, Universät Hamburg, Hamburg, Germany
| | - Mark J. Lara
- Department of Plant Biology, University of Illinois, Urbana, IL 61801, USA
| | - Klaus S. Larsen
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark
| | - Bang-Yong Lee
- Korea Polar Research Institute (KOPRI), Incheon 21990, Republic of Korea)
| | - Zhihua Liu
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
| | | | - Magnus Lund
- Department of Bioscience, Arctic Research Centre, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Massimo Lupascu
- Department of Geography, National University of Singapore, Singapore 117570
| | - Nima Madani
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Avni Malhotra
- Department of Earth System Science, Stanford University, Stanford, CA 94305
| | - Roser Matamala
- Environmental Science Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Jack McFarland
- Geology, Minerals, Energy, and Geophysics Science Center, U.S. Geological Survey, Menlo Park, CA 94025, USA
| | - A. David McGuire
- University of Alaska Fairbanks, Institute of Arctic Biology, Fairbanks, AK 99775, USA
| | | | | | - Walter C. Oechel
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
- University of Exeter, Exeter, UK
| | - David Olefeldt
- University of Alberta, Department of Renewable Resources, Edmonton, Alberta, Canada
| | - Frans-Jan W. Parmentier
- Department of Geosciences, University of Oslo, Oslo, Norway
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Norbert Pirk
- Department of Geosciences, University of Oslo, Oslo, Norway
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Ben Poulter
- NASA GSFC, Biospheric Sciences Lab., Greenbelt, MD 20771, USA
| | | | - Fereidoun Rezanezhad
- Ecohydrology Research Group, Water Institute and Department of Earth & Environmental Sciences, University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada
| | - David Risk
- St. Francis Xavier University, Antigonish, Nova Scotia, Canada
| | - Torsten Sachs
- GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, Germany
| | - Kevin Schaefer
- National Snow and Ice Data Center, Boulder, CO 80309, USA
| | - Niels M. Schmidt
- Arctic Research Centre, Department of Bioscience, Aarhus University, Roskilde, Denmark
| | - Edward A.G. Schuur
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ 86001, USA
| | - Philipp R. Semenchuk
- Division of Conservation Biology, Vegetation Ecology and Landscape Ecology, Department of Botany and Biodiversity Research, Rennweg 14, 1030 Vienna, Austria
| | - Gaius Shaver
- The Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Oliver Sonnentag
- Université de Montréal, Département de géographie & Centre d’études nordiques, 520 chemin de la Côte Sainte Catherine, Montréal, QC H2V 2B8
| | - Gregory Starr
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487, USA
| | - Claire C. Treat
- Department of Environmental and Biological Science, University of Eastern Finland, Finland
| | - Mark P. Waldrop
- Geology, Minerals, Energy, and Geophysics Science Center, U.S. Geological Survey, Menlo Park, CA 94025, USA
| | - Yihui Wang
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
| | - Jeffrey Welker
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA
- Ecology and Genetics Research Unit, University of Oulu, Finland and UArctic
| | - Christian Wille
- GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, Germany
| | - Xiaofeng Xu
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
| | - Zhen Zhang
- Department of Geographical Sciences, University of Maryland, College Park, MD 20742, USA
| | - Qianlai Zhuang
- Department of Earth, Atmospheric and Planetary Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Donatella Zona
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
- University of Sheffield, Sheffield, UK
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14
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Zhou YM, Meng GL, Tai ZJ, Han JQ, Deng JF, Wang HW, Li MH. Effects of Experimental Warming on Growing Season Temperature and Carbon Exchange in an Alpine Tundra Ecosystem. RUSS J ECOL+ 2019. [DOI: 10.1134/s1067413619050138] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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15
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Tundra microbial community taxa and traits predict decomposition parameters of stable, old soil organic carbon. ISME JOURNAL 2019; 13:2901-2915. [PMID: 31384013 DOI: 10.1038/s41396-019-0485-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 04/17/2019] [Accepted: 05/09/2019] [Indexed: 01/08/2023]
Abstract
The susceptibility of soil organic carbon (SOC) in tundra to microbial decomposition under warmer climate scenarios potentially threatens a massive positive feedback to climate change, but the underlying mechanisms of stable SOC decomposition remain elusive. Herein, Alaskan tundra soils from three depths (a fibric O horizon with litter and course roots, an O horizon with decomposing litter and roots, and a mineral-organic mix, laying just above the permafrost) were incubated. Resulting respiration data were assimilated into a 3-pool model to derive decomposition kinetic parameters for fast, slow, and passive SOC pools. Bacterial, archaeal, and fungal taxa and microbial functional genes were profiled throughout the 3-year incubation. Correlation analyses and a Random Forest approach revealed associations between model parameters and microbial community profiles, taxa, and traits. There were more associations between the microbial community data and the SOC decomposition parameters of slow and passive SOC pools than those of the fast SOC pool. Also, microbial community profiles were better predictors of model parameters in deeper soils, which had higher mineral contents and relatively greater quantities of old SOC than in surface soils. Overall, our analyses revealed the functional potential of microbial communities to decompose tundra SOC through a suite of specialized genes and taxa. These results portray divergent strategies by which microbial communities access SOC pools across varying depths, lending mechanistic insights into the vulnerability of what is considered stable SOC in tundra regions.
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16
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Altshuler I, Hamel J, Turney S, Magnuson E, Lévesque R, Greer CW, Whyte LG. Species interactions and distinct microbial communities in high Arctic permafrost affected cryosols are associated with the CH 4 and CO 2 gas fluxes. Environ Microbiol 2019; 21:3711-3727. [PMID: 31206918 DOI: 10.1111/1462-2920.14715] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 05/27/2019] [Accepted: 06/10/2019] [Indexed: 11/29/2022]
Abstract
Microbial metabolism of the thawing organic carbon stores in permafrost results in a positive feedback loop of greenhouse gas emissions. CO2 and CH4 fluxes and the associated microbial communities in Arctic cryosols are important in predicting future warming potential of the Arctic. We demonstrate that topography had an impact on CH4 and CO2 flux at a high Arctic ice-wedge polygon terrain site, with higher CO2 emissions and lower CH4 uptake at troughs compared to polygon interior soils. The pmoA sequencing suggested that USCα cluster of uncultured methanotrophs is likely responsible for observed methane sink. Community profiling revealed distinct assemblages across the terrain at different depths. Deeper soils contained higher abundances of Verrucomicrobia and Gemmatimonadetes, whereas the polygon interior had higher Acidobacteria and lower Betaproteobacteria and Deltaproteobacteria abundances. Genome sequencing of isolates from the terrain revealed presence of carbon cycling genes including ones involved in serine and ribulose monophosphate pathways. A novel hybrid network analysis identified key members that had positive and negative impacts on other species. Operational Taxonomic Units (OTUs) with numerous positive interactions corresponded to Proteobacteria, Candidatus Rokubacteria and Actinobacteria phyla, while Verrucomicrobia and Acidobacteria members had negative impacts on other species. Results indicate that topography and microbial interactions impact community composition.
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Affiliation(s)
- Ianina Altshuler
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, Macdonald Campus, McGill University, 21111 Lakeshore Rd, Ste Anne-de-Bellevue, QC, H9X 3V9, Canada
| | - Jérémie Hamel
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, QC, Québec, Canada
| | - Shaun Turney
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, Macdonald Campus, McGill University, 21111 Lakeshore Rd, Ste Anne-de-Bellevue, QC, H9X 3V9, Canada
| | - Elisse Magnuson
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, Macdonald Campus, McGill University, 21111 Lakeshore Rd, Ste Anne-de-Bellevue, QC, H9X 3V9, Canada
| | - Roger Lévesque
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, QC, Québec, Canada
| | - Charles W Greer
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, Macdonald Campus, McGill University, 21111 Lakeshore Rd, Ste Anne-de-Bellevue, QC, H9X 3V9, Canada.,National Research Council of Canada, 6100 Royalmount Avenue, Montreal, QC, H4P 2R2, Canada
| | - Lyle G Whyte
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, Macdonald Campus, McGill University, 21111 Lakeshore Rd, Ste Anne-de-Bellevue, QC, H9X 3V9, Canada
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17
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Phillips JS, McCormick AR, Einarsson Á, Grover SN, Ives AR. Spatiotemporal variation in the sign and magnitude of ecosystem engineer effects on lake ecosystem production. Ecosphere 2019. [DOI: 10.1002/ecs2.2760] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Joseph S. Phillips
- Department of Integrative Biology University of Wisconsin‐Madison Madison Wisconsin 53706 USA
| | - Amanda R. McCormick
- Department of Integrative Biology University of Wisconsin‐Madison Madison Wisconsin 53706 USA
| | - Árni Einarsson
- Mývatn Research Station Skútustaðir IS‐660 Iceland
- Faculty of Life and Environmental Sciences University of Iceland Reykjavik IS‐101 Iceland
| | - Shannon N. Grover
- Department of Integrative Biology University of Wisconsin‐Madison Madison Wisconsin 53706 USA
| | - Anthony R. Ives
- Department of Integrative Biology University of Wisconsin‐Madison Madison Wisconsin 53706 USA
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18
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Evidence for non-steady-state carbon emissions from snow-scoured alpine tundra. Nat Commun 2019; 10:1306. [PMID: 30898997 PMCID: PMC6428862 DOI: 10.1038/s41467-019-09149-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 02/20/2019] [Indexed: 11/14/2022] Open
Abstract
High-latitude warming is capable of accelerating permafrost degradation and the decomposition of previously frozen carbon. The existence of an analogous high-altitude feedback, however, has yet to be directly evaluated. We address this knowledge gap by coupling a radiocarbon-based model to 7 years (2008–2014) of continuous eddy covariance data from a snow-scoured alpine tundra meadow in Colorado, USA, where solifluction lobes are associated with discontinuous permafrost. On average, the ecosystem was a net annual source of 232 ± 54 g C m−2 (mean ± 1 standard deviation) to the atmosphere, and respiration of relatively radiocarbon-depleted (i.e., older) substrate contributes to carbon emissions during the winter. Given that alpine soils with permafrost occupy 3.6 × 106 km2 land area and are estimated to contain 66.3 Pg of soil organic carbon (4.5% of the global pool), this scenario has global implications for the mountain carbon balance and corresponding resource allocation to lower elevations. The potential contribution of high altitude permafrost as a climate feedback is unknown. Here the authors show seven years of sustained carbon emissions from snow-scoured alpine tundra including respiration of older carbon substrate from solifluction lobes associated with permafrost during the winter.
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19
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Kendrick MR, Huryn AD, Bowden WB, Deegan LA, Findlay RH, Hershey AE, Peterson BJ, Beneš JP, Schuett EB. Linking permafrost thaw to shifting biogeochemistry and food web resources in an arctic river. GLOBAL CHANGE BIOLOGY 2018; 24:5738-5750. [PMID: 30218544 DOI: 10.1111/gcb.14448] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 08/04/2018] [Accepted: 08/18/2018] [Indexed: 05/21/2023]
Abstract
Rapidly, increasing air temperatures across the Arctic are thawing permafrost and exposing vast quantities of organic carbon, nitrogen, and phosphorus to microbial processing. Shifts in the absolute and relative supplies of these elements will likely alter patterns of ecosystem productivity and change the way carbon and nutrients are delivered from upland areas to surface waters such as rivers and lakes. The ultra-oligotrophic nature of surface waters across the Arctic renders these ecosystems particularly susceptible to changes in productivity and food web dynamics as permafrost thaw alters terrestrial-aquatic linkages. The objectives of this study were to evaluate decadal-scale patterns in surface water chemistry and assess potential implications of changing water chemistry to benthic organic matter and aquatic food webs. Data were collected from the upper Kuparuk River on the North Slope of Alaska by the U.S. National Science Foundation's Long-Term Ecological Research program during 1978-2014. Analyses of these data show increases in stream water alkalinity and cation concentrations consistent with signatures of permafrost thaw. Changes are also documented for discharge-corrected nitrate concentrations (+), discharge-corrected dissolved organic carbon concentrations (-), total phosphorus concentrations (-), and δ13 C isotope values of aquatic invertebrate consumers (-). These changes show that warming temperatures and thawing permafrost in the upland environment are leading to shifts in the supply of carbon and nutrients available to surface waters and consequently changing resources that support aquatic food webs. This demonstrates that physical, geochemical, and biological changes associated with warming permafrost are fundamentally altering linkages between upland and aquatic ecosystems in rapidly changing arctic environments.
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Affiliation(s)
- Michael R Kendrick
- Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama
| | - Alexander D Huryn
- Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama
| | - William B Bowden
- Rubenstein School of Environment & Natural Resources, University of Vermont, Burlington, Vermont
| | | | - Robert H Findlay
- Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama
| | - Anne E Hershey
- Department of Biology, University of North Carolina at Greensboro, Greensboro, North Carolina
| | - Bruce J Peterson
- Ecosystems Center, Marine Biological Laboratory, Woods Hole, Massachusetts
| | - Joshua P Beneš
- Rubenstein School of Environment & Natural Resources, University of Vermont, Burlington, Vermont
| | - Elissa B Schuett
- Rubenstein School of Environment & Natural Resources, University of Vermont, Burlington, Vermont
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20
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Schuur EA, Mack MC. Ecological Response to Permafrost Thaw and Consequences for Local and Global Ecosystem Services. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2018. [DOI: 10.1146/annurev-ecolsys-121415-032349] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The Arctic may seem remote, but the unprecedented environmental changes occurring there have important consequences for global society. Of all Arctic system components, changes in permafrost (perennially frozen ground) are one of the least documented. Permafrost is degrading as a result of climate warming, and evidence is mounting that changing permafrost will have significant impacts within and outside the region. This review asks: What are key structural and functional properties of ecosystems that interact with changing permafrost, and how do these ecosystem changes affect local and global society? Here, we look beyond the classic definition of permafrost to include a broadened focus on the composition of frozen ground, including the ice and the soil organic carbon content, and how it is changing. This ecological perspective of permafrost serves to identify areas of both vulnerability and resilience as climate, ecological disturbance regimes, and the human footprint all continue to change in this sensitive and critical region of Earth.
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Affiliation(s)
| | - Michelle C. Mack
- Center for Ecosystem Science and Society, and Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona 86011, USA
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21
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McGuire AD, Genet H, Lyu Z, Pastick N, Stackpoole S, Birdsey R, D'Amore D, He Y, Rupp TS, Striegl R, Wylie BK, Zhou X, Zhuang Q, Zhu Z. Assessing historical and projected carbon balance of Alaska: A synthesis of results and policy/management implications. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2018; 28:1396-1412. [PMID: 29923353 DOI: 10.1002/eap.1768] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 04/25/2018] [Accepted: 05/16/2018] [Indexed: 06/08/2023]
Abstract
We summarize the results of a recent interagency assessment of land carbon dynamics in Alaska, in which carbon dynamics were estimated for all major terrestrial and aquatic ecosystems for the historical period (1950-2009) and a projection period (2010-2099). Between 1950 and 2009, upland and wetland (i.e., terrestrial) ecosystems of the state gained 0.4 Tg C/yr (0.1% of net primary production, NPP), resulting in a cumulative greenhouse gas radiative forcing of 1.68 × 10-3 W/m2 . The change in carbon storage is spatially variable with the region of the Northwest Boreal Landscape Conservation Cooperative (LCC) losing carbon because of fire disturbance. The combined carbon transport via various pathways through inland aquatic ecosystems of Alaska was estimated to be 41.3 Tg C/yr (17% of terrestrial NPP). During the projection period (2010-2099), carbon storage of terrestrial ecosystems of Alaska was projected to increase (22.5-70.0 Tg C/yr), primarily because of NPP increases of 10-30% associated with responses to rising atmospheric CO2 , increased nitrogen cycling, and longer growing seasons. Although carbon emissions to the atmosphere from wildfire and wetland CH4 were projected to increase for all of the climate projections, the increases in NPP more than compensated for those losses at the statewide level. Carbon dynamics of terrestrial ecosystems continue to warm the climate for four of the six future projections and cool the climate for only one of the projections. The attribution analyses we conducted indicated that the response of NPP in terrestrial ecosystems to rising atmospheric CO2 (~5% per 100 ppmv CO2 ) saturates as CO2 increases (between approximately +150 and +450 ppmv among projections). This response, along with the expectation that permafrost thaw would be much greater and release large quantities of permafrost carbon after 2100, suggests that projected carbon gains in terrestrial ecosystems of Alaska may not be sustained. From a national perspective, inclusion of all of Alaska in greenhouse gas inventory reports would ensure better accounting of the overall greenhouse gas balance of the nation and provide a foundation for considering mitigation activities in areas that are accessible enough to support substantive deployment.
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Affiliation(s)
- A David McGuire
- U.S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Hélène Genet
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Zhou Lyu
- Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana, 47907, USA
| | - Neal Pastick
- Stinger Ghaffarian Technologies Inc., contractor to the U.S. Geological Survey, Sioux Falls, South Dakota, 57198, USA
- Department of Forest Resources, University of Minnesota, St. Paul, Minnesota, 55108, USA
| | - Sarah Stackpoole
- Water Mission Area, Denver Federal Center, MS413, U.S. Geological Survey, Denver, Colorado, 80225, USA
| | - Richard Birdsey
- Woods Hole Research Center, Falmouth, Massachusetts, 02540, USA
| | - David D'Amore
- U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Juneau, Alaska, 99801, USA
| | - Yujie He
- Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana, 47907, USA
| | - T Scott Rupp
- Scenarios Network for Alaska and Arctic Planning, International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Robert Striegl
- National Research Program, U.S. Geological Survey, 3215 Marine Street, Boulder, Colorado, 80303, USA
| | - Bruce K Wylie
- The Earth Resources Observation Systems Center, U.S. Geological Survey, Sioux Falls, South Dakota, 57198, USA
| | - Xiaoping Zhou
- U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Portland, Oregon, 97208, USA
| | - Qianlai Zhuang
- Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana, 47907, USA
| | - Zhiliang Zhu
- U.S. Geological Survey, Reston, Virginia, 12201, USA
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22
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Christiansen CT, Lafreniére MJ, Henry GHR, Grogan P. Long-term deepened snow promotes tundra evergreen shrub growth and summertime ecosystem net CO 2 gain but reduces soil carbon and nutrient pools. GLOBAL CHANGE BIOLOGY 2018; 24:3508-3525. [PMID: 29411950 DOI: 10.1111/gcb.14084] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Accepted: 01/16/2018] [Indexed: 06/08/2023]
Abstract
Arctic climate warming will be primarily during winter, resulting in increased snowfall in many regions. Previous tundra research on the impacts of deepened snow has generally been of short duration. Here, we report relatively long-term (7-9 years) effects of experimentally deepened snow on plant community structure, net ecosystem CO2 exchange (NEE), and soil biogeochemistry in Canadian Low Arctic mesic shrub tundra. The snowfence treatment enhanced snow depth from 0.3 to ~1 m, increasing winter soil temperatures by ~3°C, but with no effect on summer soil temperature, moisture, or thaw depth. Nevertheless, shoot biomass of the evergreen shrub Rhododendron subarcticum was near-doubled by the snowfences, leading to a 52% increase in aboveground vascular plant biomass. Additionally, summertime NEE rates, measured in collars containing similar plant biomass across treatments, were consistently reduced ~30% in the snowfenced plots due to decreased ecosystem respiration rather than increased gross photosynthesis. Phosphate in the organic soil layer (0-10 cm depth) and nitrate in the mineral soil layer (15-25 cm depth) were substantially reduced within the snowfences (47-70 and 43%-73% reductions, respectively, across sampling times). Finally, the snowfences tended (p = .08) to reduce mineral soil layer C% by 40%, but with considerable within- and among plot variation due to cryoturbation across the landscape. These results indicate that enhanced snow accumulation is likely to further increase dominance of R. subarcticum in its favored locations, and reduce summertime respiration and soil biogeochemical pools. Since evergreens are relatively slow growing and of low stature, their increased dominance may constrain vegetation-related feedbacks to climate change. We found no evidence that deepened snow promoted deciduous shrub growth in mesic tundra, and conclude that the relatively strong R. subarcticum response to snow accumulation may explain the extensive spatial variability in observed circumpolar patterns of evergreen and deciduous shrub growth over the past 30 years.
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Affiliation(s)
- Casper T Christiansen
- Department of Biology, Queen's University, Kingston, ON, Canada
- Uni Research Climate, Bjerknes Centre for Climate Research, Bergen, Norway
| | | | - Gregory H R Henry
- Department of Geography, University of British Columbia, Vancouver, BC, Canada
| | - Paul Grogan
- Department of Biology, Queen's University, Kingston, ON, Canada
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23
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Jeong SJ, Bloom AA, Schimel D, Sweeney C, Parazoo NC, Medvigy D, Schaepman-Strub G, Zheng C, Schwalm CR, Huntzinger DN, Michalak AM, Miller CE. Accelerating rates of Arctic carbon cycling revealed by long-term atmospheric CO 2 measurements. SCIENCE ADVANCES 2018; 4:eaao1167. [PMID: 30009255 PMCID: PMC6040845 DOI: 10.1126/sciadv.aao1167] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 05/31/2018] [Indexed: 05/27/2023]
Abstract
The contemporary Arctic carbon balance is uncertain, and the potential for a permafrost carbon feedback of anywhere from 50 to 200 petagrams of carbon (Schuur et al., 2015) compromises accurate 21st-century global climate system projections. The 42-year record of atmospheric CO2 measurements at Barrow, Alaska (71.29 N, 156.79 W), reveals significant trends in regional land-surface CO2 anomalies (ΔCO2), indicating long-term changes in seasonal carbon uptake and respiration. Using a carbon balance model constrained by ΔCO2, we find a 13.4% decrease in mean carbon residence time (50% confidence range = 9.2 to 17.6%) in North Slope tundra ecosystems during the past four decades, suggesting a transition toward a boreal carbon cycling regime. Temperature dependencies of respiration and carbon uptake suggest that increases in cold season Arctic labile carbon release will likely continue to exceed increases in net growing season carbon uptake under continued warming trends.
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Affiliation(s)
- Su-Jong Jeong
- Department of Environmental Planning, Graduate School of Environmental Studies, Seoul National University, Seoul, Korea
| | - A. Anthony Bloom
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - David Schimel
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Colm Sweeney
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO 80309, USA
- National Oceanic and Atmospheric Administration/Earth System Research Laboratory, Boulder, CO 80305, USA
| | - Nicholas C. Parazoo
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - David Medvigy
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Gabriela Schaepman-Strub
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Chunmiao Zheng
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Christopher R. Schwalm
- Woods Hole Research Center, Falmouth, MA 02540, USA
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Deborah N. Huntzinger
- School of Earth Sciences and Environmental Sustainability, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Anna M. Michalak
- Department of Global Ecology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Charles E. Miller
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
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24
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Street LE, Mielke N, Woodin SJ. Phosphorus Availability Determines the Response of Tundra Ecosystem Carbon Stocks to Nitrogen Enrichment. Ecosystems 2017. [DOI: 10.1007/s10021-017-0209-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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25
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Pires CV, Schaefer CERG, Hashigushi AK, Thomazini A, Filho EIF, Mendonça ES. Soil organic carbon and nitrogen pools drive soil C-CO2 emissions from selected soils in Maritime Antarctica. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 596-597:124-135. [PMID: 28431357 DOI: 10.1016/j.scitotenv.2017.03.144] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 03/15/2017] [Accepted: 03/15/2017] [Indexed: 06/07/2023]
Abstract
The ongoing trend of increasing air temperatures will potentially affect soil organic matter (SOM) turnover and soil C-CO2 emissions in terrestrial ecosystems of Maritime Antarctica. The effects of SOM quality on this process remain little explored. We evaluated (i) the quantity and quality of soil organic matter and (ii) the potential of C release through CO2 emissions in lab conditions in different soil types from Maritime Antarctica. Soil samples (0-10 and 10-20cm) were collected in Keller Peninsula and the vicinity of Arctowski station, to determine the quantity and quality of organic matter and the potential to emit CO2 under different temperature scenarios (2, 5, 8 and 11°C) in lab. Soil organic matter mineralization is low, especially in soils with low organic C and N contents. Recalcitrant C form is predominant, especially in the passive pool, which is correlated with humic substances. Ornithogenic soils had greater C and N contents (reaching to 43.15gkg-1 and 5.22gkg-1 for total organic carbon and nitrogen, respectively). C and N were more present in the humic acid fraction. Lowest C mineralization was recorded from shallow soils on basaltic/andesites. C mineralization rates at 2°C were significant lower than at higher temperatures. Ornithogenic soils presented the lowest values of C-CO2 mineralized by g of C. On the other hand, shallow soils on basaltic/andesites were the most sensitive sites to emit C-CO2 by g of C. With permafrost degradation, soils on basaltic/andesites and sulfates are expected to release more C-CO2 than ornithogenic soils. With greater clay contents, more protection was afforded to soil organic matter, with lower microbial activity and mineralization. The trend of soil temperature increases will favor C-CO2 emissions, especially in the reduced pool of C stored and protected on permafrost, or in occasional Histosols.
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Affiliation(s)
- C V Pires
- Departamento de Solos, Universidade Federal de Viçosa, 36570-000 Viçosa, Minas Gerais, Brazil.
| | - C E R G Schaefer
- Departamento de Solos, Universidade Federal de Viçosa, 36570-000 Viçosa, Minas Gerais, Brazil.
| | - A K Hashigushi
- Departamento de Solos, Universidade Federal de Viçosa, 36570-000 Viçosa, Minas Gerais, Brazil.
| | - A Thomazini
- Departamento de Solos, Universidade Federal de Viçosa, 36570-000 Viçosa, Minas Gerais, Brazil.
| | - E I F Filho
- Departamento de Solos, Universidade Federal de Viçosa, 36570-000 Viçosa, Minas Gerais, Brazil.
| | - E S Mendonça
- Departamento de Produção Vegetal, Universidade Federal do Espírito Santo, Alegre, Espírito Santo 29000-000, Brazil.
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26
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Mauritz M, Bracho R, Celis G, Hutchings J, Natali SM, Pegoraro E, Salmon VG, Schädel C, Webb EE, Schuur EAG. Nonlinear CO 2 flux response to 7 years of experimentally induced permafrost thaw. GLOBAL CHANGE BIOLOGY 2017; 23:3646-3666. [PMID: 28208232 DOI: 10.1111/gcb.13661] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Accepted: 01/19/2017] [Indexed: 06/06/2023]
Abstract
Rapid Arctic warming is expected to increase global greenhouse gas concentrations as permafrost thaw exposes immense stores of frozen carbon (C) to microbial decomposition. Permafrost thaw also stimulates plant growth, which could offset C loss. Using data from 7 years of experimental Air and Soil warming in moist acidic tundra, we show that Soil warming had a much stronger effect on CO2 flux than Air warming. Soil warming caused rapid permafrost thaw and increased ecosystem respiration (Reco ), gross primary productivity (GPP), and net summer CO2 storage (NEE). Over 7 years Reco , GPP, and NEE also increased in Control (i.e., ambient plots), but this change could be explained by slow thaw in Control areas. In the initial stages of thaw, Reco , GPP, and NEE increased linearly with thaw across all treatments, despite different rates of thaw. As thaw in Soil warming continued to increase linearly, ground surface subsidence created saturated microsites and suppressed Reco , GPP, and NEE. However Reco and GPP remained high in areas with large Eriophorum vaginatum biomass. In general NEE increased with thaw, but was more strongly correlated with plant biomass than thaw, indicating that higher Reco in deeply thawed areas during summer months was balanced by GPP. Summer CO2 flux across treatments fit a single quadratic relationship that captured the functional response of CO2 flux to thaw, water table depth, and plant biomass. These results demonstrate the importance of indirect thaw effects on CO2 flux: plant growth and water table dynamics. Nonsummer Reco models estimated that the area was an annual CO2 source during all years of observation. Nonsummer CO2 loss in warmer, more deeply thawed soils exceeded the increases in summer GPP, and thawed tundra was a net annual CO2 source.
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Affiliation(s)
- Marguerite Mauritz
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
| | - Rosvel Bracho
- School of Forest Resources and Conservation, University of Florida, Gainesville, FL, USA
| | - Gerardo Celis
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
| | - Jack Hutchings
- Department of Geological Sciences, University of Florida, Gainesville, FL, USA
| | | | - Elaine Pegoraro
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
| | - Verity G Salmon
- Environmental Sciences Division and Climate Change Sciences Institute, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Christina Schädel
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
| | - Elizabeth E Webb
- Department of Biology, University of Florida, Gainesville, FL, USA
| | - Edward A G Schuur
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
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27
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Carbon dioxide sources from Alaska driven by increasing early winter respiration from Arctic tundra. Proc Natl Acad Sci U S A 2017; 114:5361-5366. [PMID: 28484001 DOI: 10.1073/pnas.1618567114] [Citation(s) in RCA: 124] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
High-latitude ecosystems have the capacity to release large amounts of carbon dioxide (CO2) to the atmosphere in response to increasing temperatures, representing a potentially significant positive feedback within the climate system. Here, we combine aircraft and tower observations of atmospheric CO2 with remote sensing data and meteorological products to derive temporally and spatially resolved year-round CO2 fluxes across Alaska during 2012-2014. We find that tundra ecosystems were a net source of CO2 to the atmosphere annually, with especially high rates of respiration during early winter (October through December). Long-term records at Barrow, AK, suggest that CO2 emission rates from North Slope tundra have increased during the October through December period by 73% ± 11% since 1975, and are correlated with rising summer temperatures. Together, these results imply increasing early winter respiration and net annual emission of CO2 in Alaska, in response to climate warming. Our results provide evidence that the decadal-scale increase in the amplitude of the CO2 seasonal cycle may be linked with increasing biogenic emissions in the Arctic, following the growing season. Early winter respiration was not well simulated by the Earth System Models used to forecast future carbon fluxes in recent climate assessments. Therefore, these assessments may underestimate the carbon release from Arctic soils in response to a warming climate.
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28
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Fouché J, Keller C, Allard M, Ambrosi JP. Diurnal evolution of the temperature sensitivity of CO 2 efflux in permafrost soils under control and warm conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 581-582:161-173. [PMID: 28062107 DOI: 10.1016/j.scitotenv.2016.12.089] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Revised: 12/13/2016] [Accepted: 12/13/2016] [Indexed: 06/06/2023]
Abstract
Cryosols contain ~33% of the global soil organic carbon. Cryosol warming and permafrost degradation may enhance the CO2 release to the atmosphere through the microbial decomposition. Despite the large carbon pool, the permafrost carbon feedback on the climate remains uncertain. In this study, we aimed at better understanding the diurnal evolution of the temperature sensitivity of CO2 efflux in Cryosols. A Histic Cryosol and a Turbic Cryosol were instrumented in tussock tundra ecosystems near Salluit (Nunavik, Canada). Open top chambers were installed during summer 2011 and the ground temperature, the soil moisture and meteorological variables were recorded hourly while the ecosystem respiration was measured three times per day every second day with opaque and closed dynamic chambers in control and warm stations. Despite warmer conditions, the average CO2 efflux at the control stations at the Histic site (1.29±0.45μmolCO2m-2s-1) was lower than at the Turbic site (2.30±0.74μmolCO2m-2s-1). The increase in CO2 efflux with warming was greater in the Histic Cryosol (~39%) than in the Turbic Cryosol (~16%). Our study showed that the temperature sensitivity of the ecosystem respiration evolved during the day and decreased with the experimental warming. Both sites exhibited diurnal hysteresis loops between CO2 efflux and the soil surface temperature. The width of hysteresis loops increased with the solar radiation and decreased along the growing season. We developed simple linear models that took into account the diurnal evolution of the temperature sensitivity of CO2 efflux and we estimated the seasonal cumulative carbon release to the atmosphere. The calculation using solely diurnal measurements significantly differed from the seasonal carbon release modelled hourly. Our study highlighted that the time of the day when measurements are performed should be taken into account to accurately estimate the seasonal carbon release from tundra ecosystems.
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Affiliation(s)
- Julien Fouché
- Aix-Marseille Université, CNRS, IRD UMR 34 CEREGE, Technopôle de l'Environnement Arbois-Méditerranée, BP80, 13545 Aix-en-Provence, France; Centre d'Études Nordiques, Université Laval, pav. Abitibi-Price, Québec, QC G1K 7P4, Canada; Department of Geography, Queen's University, Kingston, ON K7L 3N6, Canada.
| | - Catherine Keller
- Aix-Marseille Université, CNRS, IRD UMR 34 CEREGE, Technopôle de l'Environnement Arbois-Méditerranée, BP80, 13545 Aix-en-Provence, France
| | - Michel Allard
- Centre d'Études Nordiques, Université Laval, pav. Abitibi-Price, Québec, QC G1K 7P4, Canada
| | - Jean Paul Ambrosi
- Aix-Marseille Université, CNRS, IRD UMR 34 CEREGE, Technopôle de l'Environnement Arbois-Méditerranée, BP80, 13545 Aix-en-Provence, France
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Varolo E, Zanotelli D, Montagnani L, Tagliavini M, Zerbe S. Colonization of a Deglaciated Moraine: Contrasting Patterns of Carbon Uptake and Release from C3 and CAM Plants. PLoS One 2016; 11:e0168741. [PMID: 28033605 PMCID: PMC5199236 DOI: 10.1371/journal.pone.0168741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 12/06/2016] [Indexed: 11/27/2022] Open
Abstract
INTRODUCTION Current glacier retreat makes vast mountain ranges available for vegetation establishment and growth. As a result, carbon (C) is accumulated in the soil, in a negative feedback to climate change. Little is known about the effective C budget of these new ecosystems and how the presence of different vegetation communities influences CO2 fluxes. METHODS On the Matsch glacier forefield (Alps, Italy) we measured over two growing seasons the Net Ecosystem Exchange (NEE) of a typical grassland, dominated by the C3 Festuca halleri All., and a community dominated by the CAM rosettes Sempervivum montanum L. Using transparent and opaque chambers, with air temperature as the driver, we partitioned NEE to calculate Ecosystem Respiration (Reco) and Gross Ecosystem Exchange (GEE). In addition, soil and vegetation samples were collected from the same sites to estimate the Net Ecosystem Carbon Balance (NECB). RESULTS The two communities showed contrasting GEE but similar Reco patterns, and as a result they were significantly different in NEE during the period measured. The grassland acted as a C sink, with a total cumulated value of -46.4±35.5 g C m-2 NEE, while the plots dominated by the CAM rosettes acted as a source, with 31.9±22.4 g C m-2. In spite of the different NEE, soil analysis did not reveal significant differences in carbon accumulation of the two plant communities (1770±130 for F. halleri and 2080±230 g C m-2 for S. montanum), suggesting that processes often neglected, like lateral flows and winter respiration, can have a similar relevance as NEE in the determination of the Net Ecosystem Carbon Balance.
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Affiliation(s)
- Elisa Varolo
- Faculty of Science and Technology, Free University of Bozen/Bolzano, Bolzano, Italy
- Institute of Biology and Chemistry, University of Hildesheim, Hildesheim, Germany
| | - Damiano Zanotelli
- Faculty of Science and Technology, Free University of Bozen/Bolzano, Bolzano, Italy
| | - Leonardo Montagnani
- Faculty of Science and Technology, Free University of Bozen/Bolzano, Bolzano, Italy
- Forest Services, Autonomous Province of Bolzano, Bolzano, Italy
| | - Massimo Tagliavini
- Faculty of Science and Technology, Free University of Bozen/Bolzano, Bolzano, Italy
| | - Stefan Zerbe
- Faculty of Science and Technology, Free University of Bozen/Bolzano, Bolzano, Italy
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Greater Abundance of Betula nana and Early Onset of the Growing Season Increase Ecosystem CO2 Uptake in West Greenland. Ecosystems 2016. [DOI: 10.1007/s10021-016-9997-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Sensitivity analysis of ecosystem CO2 exchange to climate change in High Arctic tundra using an ecological process-based model. Polar Biol 2015. [DOI: 10.1007/s00300-015-1777-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Sweet SK, Griffin KL, Steltzer H, Gough L, Boelman NT. Greater deciduous shrub abundance extends tundra peak season and increases modeled net CO2 uptake. GLOBAL CHANGE BIOLOGY 2015; 21:2394-409. [PMID: 25556338 DOI: 10.1111/gcb.12852] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 11/18/2014] [Indexed: 05/24/2023]
Abstract
Satellite studies of the terrestrial Arctic report increased summer greening and longer overall growing and peak seasons since the 1980s, which increases productivity and the period of carbon uptake. These trends are attributed to increasing air temperatures and reduced snow cover duration in spring and fall. Concurrently, deciduous shrubs are becoming increasingly abundant in tundra landscapes, which may also impact canopy phenology and productivity. Our aim was to determine the influence of greater deciduous shrub abundance on tundra canopy phenology and subsequent impacts on net ecosystem carbon exchange (NEE) during the growing and peak seasons in the arctic foothills region of Alaska. We compared deciduous shrub-dominated and evergreen/graminoid-dominated community-level canopy phenology throughout the growing season using the normalized difference vegetation index (NDVI). We used a tundra plant-community-specific leaf area index (LAI) model to estimate LAI throughout the green season and a tundra-specific NEE model to estimate the impact of greater deciduous shrub abundance and associated shifts in both leaf area and canopy phenology on tundra carbon flux. We found that deciduous shrub canopies reached the onset of peak greenness 13 days earlier and the onset of senescence 3 days earlier compared to evergreen/graminoid canopies, resulting in a 10-day extension of the peak season. The combined effect of the longer peak season and greater leaf area of deciduous shrub canopies almost tripled the modeled net carbon uptake of deciduous shrub communities compared to evergreen/graminoid communities, while the longer peak season alone resulted in 84% greater carbon uptake in deciduous shrub communities. These results suggest that greater deciduous shrub abundance increases carbon uptake not only due to greater leaf area, but also due to an extension of the period of peak greenness, which extends the period of maximum carbon uptake.
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Affiliation(s)
- Shannan K Sweet
- Lamont-Doherty Earth Observatory, Department of Earth and Environmental Sciences, Columbia University, Palisades, NY, 10964, USA
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Climate change and the permafrost carbon feedback. Nature 2015; 520:171-9. [DOI: 10.1038/nature14338] [Citation(s) in RCA: 1830] [Impact Index Per Article: 203.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 02/12/2015] [Indexed: 11/08/2022]
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