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Devoie É, Connon RF, Beddoe R, Goordial J, Quinton WL, Craig JR. Disconnected active layers and unfrozen permafrost: A discussion of permafrost-related terms and definitions. Sci Total Environ 2024; 912:169017. [PMID: 38040371 DOI: 10.1016/j.scitotenv.2023.169017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/27/2023] [Accepted: 11/29/2023] [Indexed: 12/03/2023]
Abstract
Permafrost is ground that remains at or below 0 °C for two or more consecutive years. It is overlain by an active layer which thaws and freezes annually. The difference between these definitions - the active layer based on pore water phase and permafrost based on soil temperature - leads to challenges when monitoring and modelling permafrost environments. Contrary to its definition, the key properties of permafrost including hardness, bearing capacity, permeability, unfrozen water content, and energy content, depend primarily on the ice content of permafrost and not its temperature. Temperature-based measurements in permafrost systems often overlook key features, e.g. taliks and cryopegs, and comparisons between measured and modelled systems can differ energetically by up to 90 % while reporting the same temperature. Due to the shortcomings of the temperature-based definition, it is recommended that an estimate of ice content be reported alongside temperature in permafrost systems for both in-situ measurements and modelling applications. PLAIN LANGUAGE SUMMARY: Permafrost is ground that remains at or below 0 °C for two or more consecutive years. Above it sits an active layer which thaws and freezes annually (meaning that the water in the ground changes to ice each winter). The difference between these definitions - the active layer based on the state or water in the ground and permafrost based on ground temperature - leads to challenges when measuring (in the field) and modelling (using computers) permafrost environments. In addition to these challenges, the key properties of permafrost including its ability to support infrastructure, convey water, and absorb energy depend more on its ice content than its temperature. Due to the shortcomings of the temperature-based definition, it is recommended that an estimate of ice content be reported alongside temperature in permafrost systems for both field measurements and modelling applications.
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Affiliation(s)
- É Devoie
- Department of Civil Engineering, Queen's University, Canada.
| | - R F Connon
- Department of Environment and Climate Change, Government of the Northwest Territories, Canada
| | - R Beddoe
- Department of Civil Engineering, Royal Military College of Canada, Canada
| | - J Goordial
- School of Environmental Sciences, University of Guelph, Canada
| | - W L Quinton
- Cold Regions Research Centre, Wilfrid Laurier University, Canada
| | - J R Craig
- Department of Civil and Environmental Engineering, University of Waterloo, Canada
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2
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Oehri J, Schaepman-Strub G, Kim JS, Grysko R, Kropp H, Grünberg I, Zemlianskii V, Sonnentag O, Euskirchen ES, Reji Chacko M, Muscari G, Blanken PD, Dean JF, di Sarra A, Harding RJ, Sobota I, Kutzbach L, Plekhanova E, Riihelä A, Boike J, Miller NB, Beringer J, López-Blanco E, Stoy PC, Sullivan RC, Kejna M, Parmentier FJW, Gamon JA, Mastepanov M, Wille C, Jackowicz-Korczynski M, Karger DN, Quinton WL, Putkonen J, van As D, Christensen TR, Hakuba MZ, Stone RS, Metzger S, Vandecrux B, Frost GV, Wild M, Hansen B, Meloni D, Domine F, te Beest M, Sachs T, Kalhori A, Rocha AV, Williamson SN, Morris S, Atchley AL, Essery R, Runkle BRK, Holl D, Riihimaki LD, Iwata H, Schuur EAG, Cox CJ, Grachev AA, McFadden JP, Fausto RS, Göckede M, Ueyama M, Pirk N, de Boer G, Bret-Harte MS, Leppäranta M, Steffen K, Friborg T, Ohmura A, Edgar CW, Olofsson J, Chambers SD. Vegetation type is an important predictor of the arctic summer land surface energy budget. Nat Commun 2022; 13:6379. [PMID: 36316310 PMCID: PMC9622844 DOI: 10.1038/s41467-022-34049-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 10/11/2022] [Indexed: 11/05/2022] Open
Abstract
Despite the importance of high-latitude surface energy budgets (SEBs) for land-climate interactions in the rapidly changing Arctic, uncertainties in their prediction persist. Here, we harmonize SEB observations across a network of vegetated and glaciated sites at circumpolar scale (1994-2021). Our variance-partitioning analysis identifies vegetation type as an important predictor for SEB-components during Arctic summer (June-August), compared to other SEB-drivers including climate, latitude and permafrost characteristics. Differences among vegetation types can be of similar magnitude as between vegetation and glacier surfaces and are especially high for summer sensible and latent heat fluxes. The timing of SEB-flux summer-regimes (when daily mean values exceed 0 Wm-2) relative to snow-free and -onset dates varies substantially depending on vegetation type, implying vegetation controls on snow-cover and SEB-flux seasonality. Our results indicate complex shifts in surface energy fluxes with land-cover transitions and a lengthening summer season, and highlight the potential for improving future Earth system models via a refined representation of Arctic vegetation types.
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Affiliation(s)
- Jacqueline Oehri
- grid.7400.30000 0004 1937 0650Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland ,grid.14709.3b0000 0004 1936 8649Department of Biology, McGill University, 1205 Docteur Penfield, H3A 1B1 Montreal, QC Canada
| | - Gabriela Schaepman-Strub
- grid.7400.30000 0004 1937 0650Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Jin-Soo Kim
- grid.7400.30000 0004 1937 0650Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland ,grid.35030.350000 0004 1792 6846Low-Carbon and Climate Impact Research Centre, School of Energy and Environment, City University of Hong Kong, Tat Chee Ave, Kowloon Tong, Hongkong, People’s Republic of China
| | - Raleigh Grysko
- grid.7400.30000 0004 1937 0650Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Heather Kropp
- grid.256766.60000 0004 1936 7881Environmental Studies Program, Hamilton College, 198 College Hill Rd, Clinton, NY USA
| | - Inge Grünberg
- grid.10894.340000 0001 1033 7684Permafrost Research Section, Alfred-Wegener Institute, Telegrafenberg, 14473 Potsdam Germany
| | - Vitalii Zemlianskii
- grid.7400.30000 0004 1937 0650Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Oliver Sonnentag
- grid.14848.310000 0001 2292 3357Département de géographie, Université de Montréal, 2900 Edouard Montpetit Blvd, Montreal, QC H3T 1J4 Canada
| | - Eugénie S. Euskirchen
- grid.70738.3b0000 0004 1936 981XInstitute of Arctic Biology, University of Alaska Fairbanks, 2140 Koyukuk Dr, Fairbanks, AK USA
| | - Merin Reji Chacko
- grid.7400.30000 0004 1937 0650Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland ,grid.5801.c0000 0001 2156 2780Institute of Terrestrial Ecosystems, ETH Zurich, CHN, Universitätstrasse 16, 8006 Zurich, Switzerland ,grid.419754.a0000 0001 2259 5533Land Change Science Unit, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, 8903 Birmensdorf, ZH Switzerland
| | - Giovanni Muscari
- grid.410348.a0000 0001 2300 5064Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata, 605 Rome, Italy
| | - Peter D. Blanken
- grid.266190.a0000000096214564Department of Geography, University of Colorado, Boulder, CO USA
| | - Joshua F. Dean
- grid.5337.20000 0004 1936 7603School of Geographical Sciences, University of Bristol, University Rd, Bristol, UK
| | - Alcide di Sarra
- grid.5196.b0000 0000 9864 2490Department for Sustainability, ENEA, Via Enrico Fermi 45, Frascati, Italy
| | - Richard J. Harding
- grid.494924.60000 0001 1089 2266UK Centre for Ecology & Hydrology (UKCEH), MacLean Bldg, Benson Ln, Crowmarsh Gifford, Wallingford, UK
| | - Ireneusz Sobota
- grid.5374.50000 0001 0943 6490Department of Hydrology and Water Management, Faculty of Earth Sciences and Spatial Management, Nicolaus Copernicus University, Lwowska, 87-100 Toruń Poland
| | - Lars Kutzbach
- grid.9026.d0000 0001 2287 2617Center for Earth System Research and Sustainability (CEN), University of Hamburg, Bundesstrasse 53, 20146 Hamburg, Germany
| | - Elena Plekhanova
- grid.7400.30000 0004 1937 0650Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Aku Riihelä
- grid.8657.c0000 0001 2253 8678Finnish Meteorological Institute, Erik Palménin aukio 1, 00560 Helsinki, Finland
| | - Julia Boike
- grid.10894.340000 0001 1033 7684Permafrost Research Section, Alfred-Wegener Institute, Telegrafenberg, 14473 Potsdam Germany ,grid.7468.d0000 0001 2248 7639Geography Department, Humboldt-Universität zu Berlin, Unter den Linden 6, 10117 Berlin, Germany
| | - Nathaniel B. Miller
- grid.14003.360000 0001 2167 3675University of Wisconsin-Madison, Madison, WI USA
| | - Jason Beringer
- grid.1012.20000 0004 1936 7910School of Agriculture and Environment, The University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009 WA Australia
| | - Efrén López-Blanco
- grid.424543.00000 0001 0741 5039Department of Environment and Minerals, Greenland Institute of Natural Resources, Kivioq 2, Nuuk, 3900 Greenland ,grid.7048.b0000 0001 1956 2722Department of Ecoscience, Aarhus University, Nordre Ringgade 1, 8000 Aarhus C, Denmark
| | - Paul C. Stoy
- grid.14003.360000 0001 2167 3675University of Wisconsin-Madison, Madison, WI USA
| | - Ryan C. Sullivan
- grid.187073.a0000 0001 1939 4845Environmental Science Division, Argonne National Laboratory, 9700 S Cass Ave, Lemont, IL USA
| | - Marek Kejna
- grid.5374.50000 0001 0943 6490Department of Meteorology and Climatology, Faculty of Earth Sciences and Spatial Management, Nicolaus Copernicus University, Lwowska, 87-100 Toruń Poland
| | - Frans-Jan W. Parmentier
- grid.5510.10000 0004 1936 8921Center for Biogeochemistry of the Anthropocene, Department of Geosciences, University of Oslo, Sem Sælands vei 1, 0371 Oslo, Norway ,grid.4514.40000 0001 0930 2361Department of Physical Geography and Ecosystem Science, Lund University, Geocentrum II, Sölvegatan 12, 223 62 Lund, Sweden
| | - John A. Gamon
- grid.24434.350000 0004 1937 0060University of Nebraska - Lincoln, 1400 R St, Lincoln, NE USA
| | - Mikhail Mastepanov
- grid.7048.b0000 0001 1956 2722Department of Ecoscience, Aarhus University, Nordre Ringgade 1, 8000 Aarhus C, Denmark ,grid.10858.340000 0001 0941 4873Oulanka Research Station, University of Oulu, Pentti Kaiteran katu 1, 90570 Oulu, Finland
| | - Christian Wille
- grid.23731.340000 0000 9195 2461GFZ German Research Centre for Geosciences, Wissenschaftspark Albert Einstein, Telegrafenberg, 14473 Potsdam Germany
| | - Marcin Jackowicz-Korczynski
- grid.7048.b0000 0001 1956 2722Department of Ecoscience, Aarhus University, Nordre Ringgade 1, 8000 Aarhus C, Denmark ,grid.4514.40000 0001 0930 2361Department of Physical Geography and Ecosystem Science, Lund University, Geocentrum II, Sölvegatan 12, 223 62 Lund, Sweden
| | - Dirk N. Karger
- grid.419754.a0000 0001 2259 5533Swiss Federal Institute for Forest, Snow, and Landscape Research (WSL), Zürcherstrasse 111, 8903 Birmensdorf, ZH Switzerland
| | - William L. Quinton
- grid.268252.90000 0001 1958 9263Cold Regions Research Centre, Wilfrid Laurier University, 75 University Ave W, Waterloo, ON Canada
| | - Jaakko Putkonen
- grid.266862.e0000 0004 1936 8163Harold Hamm School of Geology and Geological Engineering, University of North Dakota, Grand Forks, ND USA
| | - Dirk van As
- grid.13508.3f0000 0001 1017 5662Department of Glaciology and Climate, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, 1350 Copenhagen, Denmark
| | - Torben R. Christensen
- grid.7048.b0000 0001 1956 2722Department of Ecoscience, Aarhus University, Nordre Ringgade 1, 8000 Aarhus C, Denmark ,grid.10858.340000 0001 0941 4873Oulanka Research Station, University of Oulu, Pentti Kaiteran katu 1, 90570 Oulu, Finland
| | - Maria Z. Hakuba
- grid.20861.3d0000000107068890Jet Propulsion Laboratory, CalTech, 4800 Oak Grove Dr, Pasadena, CA USA
| | - Robert S. Stone
- grid.423024.30000 0000 8485 3852NOAA Global Monitoring Laboratory, 325 Broadway, Boulder, CO USA
| | - Stefan Metzger
- grid.422235.00000 0004 6483 1479National Ecological Observatory Network, Battelle, 1685 38th St #100, Boulder, CO USA ,grid.14003.360000 0001 2167 3675Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison, 1225 W Dayton St, Madison, WI USA
| | - Baptiste Vandecrux
- grid.13508.3f0000 0001 1017 5662Department of Glaciology and Climate, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, 1350 Copenhagen, Denmark
| | - Gerald V. Frost
- grid.487865.00000 0004 5928 6410Alaska Biological Research, Inc, 2842 Goldstream Rd, Fairbanks, AK USA
| | - Martin Wild
- grid.5801.c0000 0001 2156 2780Institute for Atmospheric and Climate Science, ETH Zurich, CHN, Universitätstrasse 16, 8006 Zurich, Switzerland
| | - Birger Hansen
- grid.5254.60000 0001 0674 042XDepartment of Geosciences and Natural Resource Management, University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg, Denmark
| | - Daniela Meloni
- grid.5196.b0000 0000 9864 2490Department for Sustainability, ENEA, Lungotevere Grande Ammiraglio Thaon di Revel, 76, Rome, Italy
| | - Florent Domine
- grid.23856.3a0000 0004 1936 8390Department of Chemistry, Université Laval, Pavillon Alexandre-Vachon, 1045 Av. de la Médecine, G1V 0A6 Québec, QC Canada ,grid.23856.3a0000 0004 1936 8390Takuvik Laboratory, CNRS-INSU, Département de Biologie, Université Laval, Pavillon Alexandre-Vachon, 1045 Av. de la Médecine, G1V 0A6 Québec, QC Canada
| | - Mariska te Beest
- grid.5477.10000000120346234Copernicus Institute of Sustainable Development, Utrecht University, Vening Meinesz Building, Princetonlaan 8a, 3584 CB Utrecht, The Netherlands ,grid.412139.c0000 0001 2191 3608Centre for African Conservation Ecology, Nelson Mandela University, University Way, Summerstrand, Gqeberha, 6019 Port Elizabeth, South Africa
| | - Torsten Sachs
- grid.23731.340000 0000 9195 2461GFZ German Research Centre for Geosciences, Wissenschaftspark Albert Einstein, Telegrafenberg, 14473 Potsdam Germany
| | - Aram Kalhori
- grid.23731.340000 0000 9195 2461GFZ German Research Centre for Geosciences, Wissenschaftspark Albert Einstein, Telegrafenberg, 14473 Potsdam Germany
| | - Adrian V. Rocha
- grid.131063.60000 0001 2168 0066Department of Biological Sciences, University of Notre Dame, 100 Galvin Life Sciences, Notre Dame, IN USA
| | - Scott N. Williamson
- grid.55614.330000 0001 1302 4958Polar Knowledge Canada, Canadian High Arctic Research Station, 1 rue Uvajuq place, CP 2150 Cambridge Bay, NU Canada
| | - Sara Morris
- grid.511342.0NOAA Physical Sciences Laboratory, 325 Broadway, Boulder, CO USA
| | - Adam L. Atchley
- grid.148313.c0000 0004 0428 3079Los Alamos National Laboratory, Bikini Atoll Rd., SM 30, Los Alamos, NM USA
| | - Richard Essery
- grid.4305.20000 0004 1936 7988School of Geosciences, University of Edinburgh, Drummond St, Edinburgh, EH8 9XP UK
| | - Benjamin R. K. Runkle
- grid.411017.20000 0001 2151 0999Department of Biological & Agricultural Engineering, University of Arkansas, 1164 W Maple St, Fayetteville, AR USA
| | - David Holl
- grid.9026.d0000 0001 2287 2617Center for Earth System Research and Sustainability (CEN), University of Hamburg, Bundesstrasse 53, 20146 Hamburg, Germany
| | - Laura D. Riihimaki
- grid.423024.30000 0000 8485 3852NOAA Global Monitoring Laboratory, 325 Broadway, Boulder, CO USA ,grid.266190.a0000000096214564CIRES (Cooperative Institute for Research in Environmental Sciences), 216 UCB, University of Colorado Boulder Campus, Boulder, CO USA
| | - Hiroki Iwata
- grid.263518.b0000 0001 1507 4692Department of Environmental Science, Shinshu University, 3 Chome-1-1 Asahi, Matsumoto, Nagano, 390-8621 Japan
| | - Edward A. G. Schuur
- grid.261120.60000 0004 1936 8040Center for Ecosystem Science and Society, Northern Arizona University, S San Francisco St, Flagstaff, AZ USA
| | - Christopher J. Cox
- grid.511342.0NOAA Physical Sciences Laboratory, 325 Broadway, Boulder, CO USA
| | - Andrey A. Grachev
- DEVCOM Army Research Laboratory, Owen Rd, White Sands Missile Range, New Mexico, NM USA
| | - Joseph P. McFadden
- grid.133342.40000 0004 1936 9676Department of Geography and Earth Research Institute, University of California Santa Barbara, 5816 Ellison Hall, Isla Vista, CA USA
| | - Robert S. Fausto
- grid.13508.3f0000 0001 1017 5662Department of Glaciology and Climate, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, 1350 Copenhagen, Denmark
| | - Mathias Göckede
- grid.419500.90000 0004 0491 7318Department of Biogeochemical Signals, Max Planck Institute for Biogeochemistry, Hans-Knöll-Straße 10, 07745 Jena, Germany
| | - Masahito Ueyama
- Osaka Metropolitan University, Sakai, Kita Ward, Umeda, 1 Chome−2 − 2-600, Osaka, Japan
| | - Norbert Pirk
- grid.5510.10000 0004 1936 8921Department of Geosciences, University of Oslo, Sem Sælands vei 1, 0371 Oslo, Norway
| | - Gijs de Boer
- grid.511342.0NOAA Physical Sciences Laboratory, 325 Broadway, Boulder, CO USA ,grid.266190.a0000000096214564CIRES (Cooperative Institute for Research in Environmental Sciences), 216 UCB, University of Colorado Boulder Campus, Boulder, CO USA ,grid.266190.a0000000096214564IRISS (Integrated Remote and In Situ Sensing), University of Colorado, Boulder, CO USA
| | - M. Syndonia Bret-Harte
- grid.70738.3b0000 0004 1936 981XInstitute of Arctic Biology, University of Alaska Fairbanks, 2140 Koyukuk Dr, Fairbanks, AK USA
| | - Matti Leppäranta
- grid.7737.40000 0004 0410 2071University of Helsinki, Yliopistonkatu 4, 00100 Helsinki, Finland
| | - Konrad Steffen
- grid.419754.a0000 0001 2259 5533Swiss Federal Institute for Forest, Snow, and Landscape Research (WSL), Zürcherstrasse 111, 8903 Birmensdorf, ZH Switzerland
| | - Thomas Friborg
- grid.5254.60000 0001 0674 042XDepartment of Geosciences and Natural Resource Management, University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg, Denmark
| | - Atsumu Ohmura
- grid.5801.c0000 0001 2156 2780Institute for Atmospheric and Climate Science, ETH Zurich, CHN, Universitätstrasse 16, 8006 Zurich, Switzerland
| | - Colin W. Edgar
- grid.70738.3b0000 0004 1936 981XInstitute of Arctic Biology, University of Alaska Fairbanks, 2140 Koyukuk Dr, Fairbanks, AK USA
| | - Johan Olofsson
- grid.12650.300000 0001 1034 3451Department of Ecology and Environmental Science, Umeå University, Linnaeus väg 4-6, 907 36 Umeå, Sweden
| | - Scott D. Chambers
- grid.1089.00000 0004 0432 8812ANSTO Lucas Heights, New Illawarra Rd, Lucas Heights NSW, 2234 Sydney, NSW Australia
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Byun E, Rezanezhad F, Fairbairn L, Slowinski S, Basiliko N, Price JS, Quinton WL, Roy-Léveillée P, Webster K, Van Cappellen P. Temperature, moisture and freeze-thaw controls on CO 2 production in soil incubations from northern peatlands. Sci Rep 2021; 11:23219. [PMID: 34853354 PMCID: PMC8636591 DOI: 10.1038/s41598-021-02606-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 11/19/2021] [Indexed: 11/20/2022] Open
Abstract
Peat accumulation in high latitude wetlands represents a natural long-term carbon sink, resulting from the cumulative excess of growing season net ecosystem production over non-growing season (NGS) net mineralization in soils. With high latitudes experiencing warming at a faster pace than the global average, especially during the NGS, a major concern is that enhanced mineralization of soil organic carbon will steadily increase CO2 emissions from northern peatlands. In this study, we conducted laboratory incubations with soils from boreal and temperate peatlands across Canada. Peat soils were pretreated for different soil moisture levels, and CO2 production rates were measured at 12 sequential temperatures, covering a range from - 10 to + 35 °C including one freeze-thaw event. On average, the CO2 production rates in the boreal peat samples increased more sharply with temperature than in the temperate peat samples. For same temperature, optimum soil moisture levels for CO2 production were higher in the peat samples from more flooded sites. However, standard reaction kinetics (e.g., Q10 temperature coefficient and Arrhenius equation) failed to account for the apparent lack of temperature dependence of CO2 production rates measured below 0 °C, and a sudden increase after a freezing event. Thus, we caution against using the simple kinetic expressions to represent the CO2 emissions from northern peatlands, especially regarding the long NGS period with multiple soil freeze and thaw events.
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Affiliation(s)
- Eunji Byun
- Ecohydrology Research Group, Department of Earth and Environmental Sciences and Water Institute, University of Waterloo, Waterloo, ON, Canada.
| | - Fereidoun Rezanezhad
- Ecohydrology Research Group, Department of Earth and Environmental Sciences and Water Institute, University of Waterloo, Waterloo, ON, Canada.
| | - Linden Fairbairn
- Ecohydrology Research Group, Department of Earth and Environmental Sciences and Water Institute, University of Waterloo, Waterloo, ON, Canada
- Environment and Climate Change Canada, Toronto, ON, Canada
| | - Stephanie Slowinski
- Ecohydrology Research Group, Department of Earth and Environmental Sciences and Water Institute, University of Waterloo, Waterloo, ON, Canada
| | - Nathan Basiliko
- Department of Biology and Vale Living With Lakes Centre, Laurentian University, Sudbury, ON, Canada
| | - Jonathan S Price
- Department of Geography and Environmental Management, University of Waterloo, Waterloo, ON, Canada
| | - William L Quinton
- Cold Regions Research Centre, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Pascale Roy-Léveillée
- Environment and Climate Change Canada, Toronto, ON, Canada
- Université Laval, Quebec City, QC, Canada
| | - Kara Webster
- Canadian Forest Service Great Lakes Forestry Centre - Natural Resources Canada, Sault Ste Marie, ON, Canada
| | - Philippe Van Cappellen
- Ecohydrology Research Group, Department of Earth and Environmental Sciences and Water Institute, University of Waterloo, Waterloo, ON, Canada.
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4
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Ackley C, Tank SE, Haynes KM, Rezanezhad F, McCarter C, Quinton WL. Coupled hydrological and geochemical impacts of wildfire in peatland-dominated regions of discontinuous permafrost. Sci Total Environ 2021; 782:146841. [PMID: 33848861 DOI: 10.1016/j.scitotenv.2021.146841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 06/12/2023]
Abstract
Naturally-ignited wildfires are increasing in frequency and severity in northern regions, contributing to rapid permafrost thaw-induced landscape change driven by climate warming. Low-severity wildfires typically result in minor organic matter loss. The impacts of such fires on the hydrological and geochemical dynamics of peat plateau-wetland complexes have not been examined. In 2014, a low-severity wildfire, with minimal ground surface damage, burned approximately one-half of a 5 ha permafrost plateau in the wetland-dominated landscape of the Scotty Creek watershed, Northwest Territories, Canada, in the discontinuous permafrost zone. In March 2016, hydrometeorological and permafrost conditions on the burned and unaffected plateaus were monitored including snowpack characteristics and surface energy dynamics. Pore water samples were collected from the saturated layer as thaw progressed throughout the growing season on the burned and unaffected plateaus. Repeated probing of the frost table depth was coupled with laboratory analyses of peat physical and hydraulic characteristics performed on peat cores collected from the top 20 cm of the ground surface in the burned and unaffected plots. The higher transmissivity of the burned forest canopy accelerated snowmelt promoting earlier onset of the thawing season and increased the ground heat flux to melt ground ice. Wildfire increased the thickness of the supra-permafrost layer, including the active layer and talik, resulting in a more uniform subsurface with limited depressional storage capacity and reduced preferential runoff flowpaths across the burned plateau. The incorporation of ash and char into the peat matrix reduced pore diameters, promoting greater subsurface soil moisture retention and longer pore water residence times ultimately providing greater opportunity for soil-water interaction and biogeochemical reactions. Consequently, pore water showed elevated dissolved solutes, dissolved organic matter and mercury concentrations in the burned site. Low-severity wildfires have the potential to trigger a series of complex, inter-related hydrological, thermal and biogeochemical processes and feedbacks.
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Affiliation(s)
- Caren Ackley
- Cold Regions Research Centre, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Suzanne E Tank
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Kristine M Haynes
- Cold Regions Research Centre, Wilfrid Laurier University, Waterloo, ON, Canada.
| | - Fereidoun Rezanezhad
- Ecohydrology Research Group, Department of Earth and Environmental Sciences and Water Institute, University of Waterloo, Waterloo, ON, Canada
| | - Colin McCarter
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, ON, Canada
| | - William L Quinton
- Cold Regions Research Centre, Wilfrid Laurier University, Waterloo, ON, Canada
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5
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Hutchins RHS, Tank SE, Olefeldt D, Quinton WL, Spence C, Dion N, Estop-Aragonés C, Mengistu SG. Fluvial CO 2 and CH 4 patterns across wildfire-disturbed ecozones of subarctic Canada: Current status and implications for future change. Glob Chang Biol 2020; 26:2304-2319. [PMID: 31834984 DOI: 10.1111/gcb.14960] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 11/28/2019] [Indexed: 06/10/2023]
Abstract
Despite occupying a small fraction of the landscape, fluvial networks are disproportionately large emitters of CO2 and CH4 , with the potential to offset terrestrial carbon sinks. Yet the extent of this offset remains uncertain, because current estimates of fluvial emissions often do not integrate beyond individual river reaches and over the entire fluvial network in complex landscapes. Here we studied broad patterns of concentrations and isotopic signatures of CO2 and CH4 in 50 streams in the western boreal biome of Canada, across an area of 250,000 km2 . Our study watersheds differ starkly in their geology (sedimentary and shield), permafrost extent (sporadic to extensive discontinuous) and land cover (large variability in lake and wetland extents). We also investigated the effect of wildfire, as half of our study streams drained watersheds affected by megafires that occurred 3 years prior. Similar to other boreal regions, we found that stream CO2 concentrations were primarily associated with greater terrestrial productivity and warmer climates, and decreased downstream within the fluvial network. No effects of recent wildfire, bedrock geology or land cover composition were found. The isotopic signatures suggested dominance of biogenic CO2 sources, despite dominant carbonate bedrock in parts of the study region. Fluvial CH4 concentrations had a high variability which could not be explained by any landscape factors. Estimated fluvial CO2 emissions were 0.63 (0.09-6.06, 95% CI) and 0.29 (0.17-0.44, 95% CI) g C m-2 year-1 at the landscape scale using a stream network modelling and a mass balance approach, respectively, a small but potentially important component of the landscape C balance. These fluvial CO2 emissions are lower than in other northern regions, likely due to a drier climate. Overall, our study suggests that fluvial CO2 emissions are unlikely to be sensitive to altered fire regimes, but that warming and permafrost thaw will increase emissions significantly.
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Affiliation(s)
- Ryan H S Hutchins
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Suzanne E Tank
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - David Olefeldt
- Department of Renewable Resources, University of Alberta, Edmonton, AB, Canada
| | - William L Quinton
- Cold Regions Research Centre, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Christopher Spence
- National Hydrology Research Centre, Environment and Climate Change Canada, Saskatoon, SK, Canada
| | - Nicole Dion
- Water Resources Department, Government of Northwest Territories, Yellowknife, NT, Canada
| | | | - Samson G Mengistu
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
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Langford JE, Schincariol RA, Nagare RM, Quinton WL, Mohammed AA. Transient and Transition Factors in Modeling Permafrost Thaw and Groundwater Flow. Ground Water 2020; 58:258-268. [PMID: 31081132 DOI: 10.1111/gwat.12903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 05/04/2019] [Accepted: 05/07/2019] [Indexed: 06/09/2023]
Abstract
Permafrost covers approximately 24% of the Northern Hemisphere, and much of it is degrading, which causes infrastructure failures and ecosystem transitions. Understanding groundwater and heat flow processes in permafrost environments is challenging due to spatially and temporarily varying hydraulic connections between water above and below the near-surface discontinuous frozen zone. To characterize the transitional period of permafrost degradation, a three-dimensional model of a permafrost plateau that includes the supra-permafrost zone and surrounding wetlands was developed. The model is based on the Scotty Creek basin in the Northwest Territories, Canada. FEFLOW groundwater flow and heat transport modeling software is used in conjunction with the piFreeze plug-in, to account for phase changes between ice and water. The Simultaneous Heat and Water (SHAW) flow model is used to calculate ground temperatures and surface water balance, which are then used as FEFLOW boundary conditions. As simulating actual permafrost evolution would require hundreds of years of climate variations over an evolving landscape, whose geomorphic features are unknown, methodologies for developing permafrost initial conditions for transient simulations were investigated. It was found that a model initialized with a transient spin-up methodology, that includes an unfrozen layer between the permafrost table and ground surface, yields better results than with steady-state permafrost initial conditions. This study also demonstrates the critical role that variations in land surface and permafrost table microtopography, along with talik development, play in permafrost degradation. Modeling permafrost dynamics will allow for the testing of remedial measures to stabilize permafrost in high value infrastructure environments.
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Affiliation(s)
- Joelle E Langford
- Department of Earth Sciences, University of Western Ontario, 1151 Richmond Street, N6A 5B7, London, ON, Canada
| | | | - Ranjeet M Nagare
- ARKK Engineering, #168 2301 Premier Way, T8H 2K8 Edmonton, AB, Canada
| | - William L Quinton
- Cold Regions Research Centre, Wilfrid Laurier University, 75 Avenue West, N2L 3C5 Waterloo, ON, Canada
| | - Aaron A Mohammed
- Department of Geoscience, University of Calgary, 2500 University Dr. N.W., T2N 1N4 Calgary, AB, Canada
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Liu Z, Kimball JS, Parazoo NC, Ballantyne AP, Wang WJ, Madani N, Pan CG, Watts JD, Reichle RH, Sonnentag O, Marsh P, Hurkuck M, Helbig M, Quinton WL, Zona D, Ueyama M, Kobayashi H, Euskirchen ES. Increased high-latitude photosynthetic carbon gain offset by respiration carbon loss during an anomalous warm winter to spring transition. Glob Chang Biol 2020; 26:682-696. [PMID: 31596019 DOI: 10.1111/gcb.14863] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 07/21/2019] [Indexed: 06/10/2023]
Abstract
Arctic and boreal ecosystems play an important role in the global carbon (C) budget, and whether they act as a future net C sink or source depends on climate and environmental change. Here, we used complementary in situ measurements, model simulations, and satellite observations to investigate the net carbon dioxide (CO2 ) seasonal cycle and its climatic and environmental controls across Alaska and northwestern Canada during the anomalously warm winter to spring conditions of 2015 and 2016 (relative to 2010-2014). In the warm spring, we found that photosynthesis was enhanced more than respiration, leading to greater CO2 uptake. However, photosynthetic enhancement from spring warming was partially offset by greater ecosystem respiration during the preceding anomalously warm winter, resulting in nearly neutral effects on the annual net CO2 balance. Eddy covariance CO2 flux measurements showed that air temperature has a primary influence on net CO2 exchange in winter and spring, while soil moisture has a primary control on net CO2 exchange in the fall. The net CO2 exchange was generally more moisture limited in the boreal region than in the Arctic tundra. Our analysis indicates complex seasonal interactions of underlying C cycle processes in response to changing climate and hydrology that may not manifest in changes in net annual CO2 exchange. Therefore, a better understanding of the seasonal response of C cycle processes may provide important insights for predicting future carbon-climate feedbacks and their consequences on atmospheric CO2 dynamics in the northern high latitudes.
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Affiliation(s)
- Zhihua Liu
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
- Numerical Terradynamic Simulation Group, WA Franke College of Forestry and Conservation, University of Montana, Missoula, MT, USA
| | - John S Kimball
- Numerical Terradynamic Simulation Group, WA Franke College of Forestry and Conservation, University of Montana, Missoula, MT, USA
- Department of Ecosystem and Conservation Sciences, WA Franke College of Forestry and Conservation, University of Montana, Missoula, MT, USA
| | - Nicholas C Parazoo
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Ashley P Ballantyne
- Department of Ecosystem and Conservation Sciences, WA Franke College of Forestry and Conservation, University of Montana, Missoula, MT, USA
| | - Wen J Wang
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
| | - Nima Madani
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Caleb G Pan
- Numerical Terradynamic Simulation Group, WA Franke College of Forestry and Conservation, University of Montana, Missoula, MT, USA
| | | | | | - Oliver Sonnentag
- Département de géographie and Centre d'études nordiques, Université de Montréal, Montreal, QC, Canada
| | - Philip Marsh
- Cold Regions Research Centre, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Miriam Hurkuck
- Département de géographie and Centre d'études nordiques, Université de Montréal, Montreal, QC, Canada
| | - Manuel Helbig
- School of Geography and Earth Sciences, McMaster University, Hamilton, ON, Canada
| | - William L Quinton
- Cold Regions Research Centre, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Donatella Zona
- Global Change Research Group, Department of Biology, San Diego State University, San Diego, CA, USA
| | - Masahito Ueyama
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Japan
| | - Hideki Kobayashi
- Institute of Arctic Climate and Environment Research, Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan
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Gibson CM, Chasmer LE, Thompson DK, Quinton WL, Flannigan MD, Olefeldt D. Wildfire as a major driver of recent permafrost thaw in boreal peatlands. Nat Commun 2018; 9:3041. [PMID: 30072751 PMCID: PMC6072743 DOI: 10.1038/s41467-018-05457-1] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 07/03/2018] [Indexed: 11/08/2022] Open
Abstract
Permafrost vulnerability to climate change may be underestimated unless effects of wildfire are considered. Here we assess impacts of wildfire on soil thermal regime and rate of thermokarst bog expansion resulting from complete permafrost thaw in western Canadian permafrost peatlands. Effects of wildfire on permafrost peatlands last for 30 years and include a warmer and deeper active layer, and spatial expansion of continuously thawed soil layers (taliks). These impacts on the soil thermal regime are associated with a tripled rate of thermokarst bog expansion along permafrost edges. Our results suggest that wildfire is directly responsible for 2200 ± 1500 km2 (95% CI) of thermokarst bog development in the study region over the last 30 years, representing ~25% of all thermokarst bog expansion during this period. With increasing fire frequency under a warming climate, this study emphasizes the need to consider wildfires when projecting future circumpolar permafrost thaw.
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Affiliation(s)
- Carolyn M Gibson
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2R3, Canada
| | - Laura E Chasmer
- Department of Geography, University of Lethbridge, Lethbridge, AB, T1K 6T5, Canada
| | - Dan K Thompson
- Natural Resources Canada, Canadian Forest Service, Edmonton, AB, T6H 3S5, Canada
| | - William L Quinton
- Cold Regions Research Centre, Wilfrid Laurier University, Waterloo, ON, N2L 3C5, Canada
| | - Mike D Flannigan
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2R3, Canada
| | - David Olefeldt
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2R3, Canada.
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Helbig M, Chasmer LE, Desai AR, Kljun N, Quinton WL, Sonnentag O. Direct and indirect climate change effects on carbon dioxide fluxes in a thawing boreal forest-wetland landscape. Glob Chang Biol 2017; 23:3231-3248. [PMID: 28132402 DOI: 10.1111/gcb.13638] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Accepted: 12/26/2016] [Indexed: 06/06/2023]
Abstract
In the sporadic permafrost zone of northwestern Canada, boreal forest carbon dioxide (CO2 ) fluxes will be altered directly by climate change through changing meteorological forcing and indirectly through changes in landscape functioning associated with thaw-induced collapse-scar bog ('wetland') expansion. However, their combined effect on landscape-scale net ecosystem CO2 exchange (NEELAND ), resulting from changing gross primary productivity (GPP) and ecosystem respiration (ER), remains unknown. Here, we quantify indirect land cover change impacts on NEELAND and direct climate change impacts on modeled temperature- and light-limited NEELAND of a boreal forest-wetland landscape. Using nested eddy covariance flux towers, we find both GPP and ER to be larger at the landscape compared to the wetland level. However, annual NEELAND (-20 g C m-2 ) and wetland NEE (-24 g C m-2 ) were similar, suggesting negligible wetland expansion effects on NEELAND . In contrast, we find non-negligible direct climate change impacts when modeling NEELAND using projected air temperature and incoming shortwave radiation. At the end of the 21st century, modeled GPP mainly increases in spring and fall due to reduced temperature limitation, but becomes more frequently light-limited in fall. In a warmer climate, ER increases year-round in the absence of moisture stress resulting in net CO2 uptake increases in the shoulder seasons and decreases during the summer. Annually, landscape net CO2 uptake is projected to decline by 25 ± 14 g C m-2 for a moderate and 103 ± 38 g C m-2 for a high warming scenario, potentially reversing recently observed positive net CO2 uptake trends across the boreal biome. Thus, even without moisture stress, net CO2 uptake of boreal forest-wetland landscapes may decline, and ultimately, these landscapes may turn into net CO2 sources under continued anthropogenic CO2 emissions. We conclude that NEELAND changes are more likely to be driven by direct climate change rather than by indirect land cover change impacts.
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Affiliation(s)
- Manuel Helbig
- Département de géographie & Centre d'études nordiques, Université de Montréal, 520 Chemin de la Côte Sainte-Catherine, Montréal, QC, H2V 2B8, Canada
| | - Laura E Chasmer
- Department of Geography, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada
| | - Ankur R Desai
- Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Natascha Kljun
- Department of Geography, Swansea University, Singleton Park, Swansea, SA28PP, UK
| | - William L Quinton
- Cold Regions Research Centre, Wilfrid Laurier University, Waterloo, ON, N2L 3C5, Canada
| | - Oliver Sonnentag
- Département de géographie & Centre d'études nordiques, Université de Montréal, 520 Chemin de la Côte Sainte-Catherine, Montréal, QC, H2V 2B8, Canada
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Helbig M, Chasmer LE, Kljun N, Quinton WL, Treat CC, Sonnentag O. The positive net radiative greenhouse gas forcing of increasing methane emissions from a thawing boreal forest-wetland landscape. Glob Chang Biol 2017; 23:2413-2427. [PMID: 27689625 DOI: 10.1111/gcb.13520] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 09/20/2016] [Indexed: 06/06/2023]
Abstract
At the southern margin of permafrost in North America, climate change causes widespread permafrost thaw. In boreal lowlands, thawing forested permafrost peat plateaus ('forest') lead to expansion of permafrost-free wetlands ('wetland'). Expanding wetland area with saturated and warmer organic soils is expected to increase landscape methane (CH4 ) emissions. Here, we quantify the thaw-induced increase in CH4 emissions for a boreal forest-wetland landscape in the southern Taiga Plains, Canada, and evaluate its impact on net radiative forcing relative to potential long-term net carbon dioxide (CO2 ) exchange. Using nested wetland and landscape eddy covariance net CH4 flux measurements in combination with flux footprint modeling, we find that landscape CH4 emissions increase with increasing wetland-to-forest ratio. Landscape CH4 emissions are most sensitive to this ratio during peak emission periods, when wetland soils are up to 10 °C warmer than forest soils. The cumulative growing season (May-October) wetland CH4 emission of ~13 g CH4 m-2 is the dominating contribution to the landscape CH4 emission of ~7 g CH4 m-2 . In contrast, forest contributions to landscape CH4 emissions appear to be negligible. The rapid wetland expansion of 0.26 ± 0.05% yr-1 in this region causes an estimated growing season increase of 0.034 ± 0.007 g CH4 m-2 yr-1 in landscape CH4 emissions. A long-term net CO2 uptake of >200 g CO2 m-2 yr-1 is required to offset the positive radiative forcing of increasing CH4 emissions until the end of the 21st century as indicated by an atmospheric CH4 and CO2 concentration model. However, long-term apparent carbon accumulation rates in similar boreal forest-wetland landscapes and eddy covariance landscape net CO2 flux measurements suggest a long-term net CO2 uptake between 49 and 157 g CO2 m-2 yr-1 . Thus, thaw-induced CH4 emission increases likely exert a positive net radiative greenhouse gas forcing through the 21st century.
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Affiliation(s)
- Manuel Helbig
- Département de Géographie, Université de Montréal & Centre d'études nordiques, 520 Chemin de la Côte Sainte-Catherine, Montréal, QC, H2V 2B8, Canada
| | - Laura E Chasmer
- Department of Geography, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada
| | - NatasCha Kljun
- Department of Geography, Swansea University, Singleton Park, Swansea, SA28PP, UK
| | - William L Quinton
- Cold Regions Research Centre, Wilfrid Laurier University, Waterloo, ON, N2L 3C5, Canada
| | - Claire C Treat
- Water and Environmental Research Center, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA
- U.S. Geological Survey, Menlo Park, CA, 94025, USA
| | - Oliver Sonnentag
- Département de Géographie, Université de Montréal & Centre d'études nordiques, 520 Chemin de la Côte Sainte-Catherine, Montréal, QC, H2V 2B8, Canada
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Helbig M, Wischnewski K, Kljun N, Chasmer LE, Quinton WL, Detto M, Sonnentag O. Regional atmospheric cooling and wetting effect of permafrost thaw-induced boreal forest loss. Glob Chang Biol 2016; 22:4048-4066. [PMID: 27153776 DOI: 10.1111/gcb.13348] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 04/02/2016] [Indexed: 06/05/2023]
Abstract
In the sporadic permafrost zone of North America, thaw-induced boreal forest loss is leading to permafrost-free wetland expansion. These land cover changes alter landscape-scale surface properties with potentially large, however, still unknown impacts on regional climates. In this study, we combine nested eddy covariance flux tower measurements with satellite remote sensing to characterize the impacts of boreal forest loss on albedo, eco-physiological and aerodynamic surface properties, and turbulent energy fluxes of a lowland boreal forest region in the Northwest Territories, Canada. Planetary boundary layer modelling is used to estimate the potential forest loss impact on regional air temperature and atmospheric moisture. We show that thaw-induced conversion of forests to wetlands increases albedo: and bulk surface conductance for water vapour and decreases aerodynamic surface temperature. At the same time, heat transfer efficiency is reduced. These shifts in land surface properties increase latent at the expense of sensible heat fluxes, thus, drastically reducing Bowen ratios. Due to the lower albedo of forests and their masking effect of highly reflective snow, available energy is lower in wetlands, especially in late winter. Modelling results demonstrate that a conversion of a present-day boreal forest-wetland to a hypothetical homogeneous wetland landscape could induce a near-surface cooling effect on regional air temperatures of up to 3-4 °C in late winter and 1-2 °C in summer. An atmospheric wetting effect in summer is indicated by a maximum increase in water vapour mixing ratios of 2 mmol mol-1 . At the same time, maximum boundary layer heights are reduced by about a third of the original height. In fall, simulated air temperature and atmospheric moisture between the two scenarios do not differ. Therefore, permafrost thaw-induced boreal forest loss may modify regional precipitation patterns and slow down regional warming trends.
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Affiliation(s)
- Manuel Helbig
- Département de géographie & Centre d'études nordiques, Université de Montréal, 520 Chemin de la Côte Sainte-Catherine, Montréal, QC, H2V 2B8, Canada
| | - Karoline Wischnewski
- Département de géographie & Centre d'études nordiques, Université de Montréal, 520 Chemin de la Côte Sainte-Catherine, Montréal, QC, H2V 2B8, Canada
| | - Natascha Kljun
- Department of Geography, Swansea University, Singleton Park, Swansea SA28PP, Swansea, UK
| | - Laura E Chasmer
- Department of Geography, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada
| | - William L Quinton
- Cold Regions Research Centre, Wilfrid Laurier University, 75 University Ave. W, Waterloo, ON N2L 3C5, Canada
| | - Matteo Detto
- Smithsonian Tropical Research Institute, Luis Clement Ave., Bldg. 401 Tupper, Balboa Ancon, Panama, Republica de Panama
| | - Oliver Sonnentag
- Département de géographie & Centre d'études nordiques, Université de Montréal, 520 Chemin de la Côte Sainte-Catherine, Montréal, QC, H2V 2B8, Canada
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Baltzer JL, Veness T, Chasmer LE, Sniderhan AE, Quinton WL. Forests on thawing permafrost: fragmentation, edge effects, and net forest loss. Glob Chang Biol 2014; 20:824-834. [PMID: 23939809 DOI: 10.1111/gcb.12349] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 07/30/2013] [Indexed: 06/02/2023]
Abstract
Much of the world's boreal forest occurs on permafrost (perennially cryotic ground). As such, changes in permafrost conditions have implications for forest function and, within the zone of discontinuous permafrost (30-80% permafrost in areal extent), distribution. Here, forested peat plateaus underlain by permafrost are elevated above the surrounding permafrost-free wetlands; as permafrost thaws, ground surface subsidence leads to waterlogging at forest margins. Within the North American subarctic, recent warming has produced rapid, widespread permafrost thaw and corresponding forest loss. Although permafrost thaw-induced forest loss provides a natural analogue to deforestation occurring in more southerly locations, we know little about how fragmentation relates to subsequent permafrost thaw and forest loss or the role of changing conditions at the edges of forested plateaus. We address these knowledge gaps by (i) examining the relationship of forest loss to the degree of fragmentation in a boreal peatland in the Northwest Territories, Canada; and (ii) quantifying associated biotic and abiotic changes occurring across forest-wetland transitions and extending into the forested plateaus (i.e., edge effects). We demonstrate that the rate of forest loss correlates positively with the degree of fragmentation as quantified by perimeter to area ratio of peat plateaus (edge : area). Changes in depth of seasonal thaw, soil moisture, and effective leaf area index (LAIe ) penetrated the plateau forests by 3-15 m. Water uptake by trees was sevenfold greater in the plateau interior than at the edges with direct implications for tree radial growth. A negative relationship existed between LAIe and soil moisture, suggesting that changes in vegetation physiological function may contribute to changing edge conditions while simultaneously being affected by these changes. Enhancing our understanding of mechanisms contributing to differential rates of permafrost thaw and associated forest loss is critical for predicting future interactions between the land surface processes and the climate system in high-latitude regions.
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Affiliation(s)
- Jennifer L Baltzer
- Biology Department, Wilfrid Laurier University, 75 University Ave. W, Waterloo, ON, Canada, N2L 3C5; Centre for Cold Regions & Water Science, Wilfrid Laurier University, 75 University Ave. W, Waterloo, ON, Canada, N2L 3C5
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Zhang Y, Carey SK, Quinton WL. Evaluation of the algorithms and parameterizations for ground thawing and freezing simulation in permafrost regions. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jd009343] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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