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Anthony KMW, Zimov SA, Grosse G, Jones MC, Anthony PM, Chapin FS, Finlay JC, Mack MC, Davydov S, Frenzel P, Frolking S. A shift of thermokarst lakes from carbon sources to sinks during the Holocene epoch. Nature 2014; 511:452-6. [PMID: 25043014 DOI: 10.1038/nature13560] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Accepted: 06/02/2014] [Indexed: 11/09/2022]
Abstract
Thermokarst lakes formed across vast regions of Siberia and Alaska during the last deglaciation and are thought to be a net source of atmospheric methane and carbon dioxide during the Holocene epoch. However, the same thermokarst lakes can also sequester carbon, and it remains uncertain whether carbon uptake by thermokarst lakes can offset their greenhouse gas emissions. Here we use field observations of Siberian permafrost exposures, radiocarbon dating and spatial analyses to quantify Holocene carbon stocks and fluxes in lake sediments overlying thawed Pleistocene-aged permafrost. We find that carbon accumulation in deep thermokarst-lake sediments since the last deglaciation is about 1.6 times larger than the mass of Pleistocene-aged permafrost carbon released as greenhouse gases when the lakes first formed. Although methane and carbon dioxide emissions following thaw lead to immediate radiative warming, carbon uptake in peat-rich sediments occurs over millennial timescales. We assess thermokarst-lake carbon feedbacks to climate with an atmospheric perturbation model and find that thermokarst basins switched from a net radiative warming to a net cooling climate effect about 5,000 years ago. High rates of Holocene carbon accumulation in 20 lake sediments (47 ± 10 grams of carbon per square metre per year; mean ± standard error) were driven by thermokarst erosion and deposition of terrestrial organic matter, by nutrient release from thawing permafrost that stimulated lake productivity and by slow decomposition in cold, anoxic lake bottoms. When lakes eventually drained, permafrost formation rapidly sequestered sediment carbon. Our estimate of about 160 petagrams of Holocene organic carbon in deep lake basins of Siberia and Alaska increases the circumpolar peat carbon pool estimate for permafrost regions by over 50 per cent (ref. 6). The carbon in perennially frozen drained lake sediments may become vulnerable to mineralization as permafrost disappears, potentially negating the climate stabilization provided by thermokarst lakes during the late Holocene.
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Affiliation(s)
- K M Walter Anthony
- Water and Environmental Research Center, University of Alaska, Fairbanks, Alaska 99775-5860, USA
| | - S A Zimov
- Northeast Scientific Station, Pacific Institute for Geography, Far-East Branch, Russian Academy of Sciences, Cherskii 678830, Russia
| | - G Grosse
- 1] Geophysical Institute, University of Alaska, Fairbanks, Alaska 99775-7320, USA [2] Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam 14473, Germany
| | - M C Jones
- 1] Water and Environmental Research Center, University of Alaska, Fairbanks, Alaska 99775-5860, USA [2] US Geological Survey, Reston, Virginia 20192, USA
| | - P M Anthony
- Water and Environmental Research Center, University of Alaska, Fairbanks, Alaska 99775-5860, USA
| | - F S Chapin
- Institute of Arctic Biology, University of Alaska, Fairbanks, Alaska 99775-7000, USA
| | - J C Finlay
- Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, Minnesota 55108, USA
| | - M C Mack
- Department of Biology, University of Florida, Gainesville, Florida 32611, USA
| | - S Davydov
- Northeast Scientific Station, Pacific Institute for Geography, Far-East Branch, Russian Academy of Sciences, Cherskii 678830, Russia
| | - P Frenzel
- Max Planck Institute for Terrestrial Microbiology, Marburg 35043, Germany
| | - S Frolking
- Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, New Hampshire 03824-3525, USA
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Zimov SA, Zimova GM, Daviodov SP, Daviodova AI, Voropaev YV, Voropaeva ZV, Prosiannikov SF, Prosiannikova OV, Semiletova IV, Semiletov IP. Winter biotic activity and production of CO2in Siberian soils: A factor in the greenhouse effect. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/92jd02473] [Citation(s) in RCA: 122] [Impact Index Per Article: 10.2] [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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Walter KM, Chanton JP, Chapin FS, Schuur EAG, Zimov SA. Methane production and bubble emissions from arctic lakes: Isotopic implications for source pathways and ages. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jg000569] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.3] [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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Affiliation(s)
- K. M. Walter
- Water and Environmental Research Center, University of Alaska, Fairbanks, AK 99775, USA
- International Arctic Research Center, University of Alaska, Fairbanks, AK 99775, USA
- School of Geography, University of Southampton, UK
- College of Natural Sciences, University of Alaska, Fairbanks, AK 99775, USA
- Geophysical Institute, University of Alaska, Fairbanks, AK 99775, USA
| | - M. E. Edwards
- Water and Environmental Research Center, University of Alaska, Fairbanks, AK 99775, USA
- International Arctic Research Center, University of Alaska, Fairbanks, AK 99775, USA
- School of Geography, University of Southampton, UK
- College of Natural Sciences, University of Alaska, Fairbanks, AK 99775, USA
- Geophysical Institute, University of Alaska, Fairbanks, AK 99775, USA
| | - G. Grosse
- Water and Environmental Research Center, University of Alaska, Fairbanks, AK 99775, USA
- International Arctic Research Center, University of Alaska, Fairbanks, AK 99775, USA
- School of Geography, University of Southampton, UK
- College of Natural Sciences, University of Alaska, Fairbanks, AK 99775, USA
- Geophysical Institute, University of Alaska, Fairbanks, AK 99775, USA
| | - S. A. Zimov
- Water and Environmental Research Center, University of Alaska, Fairbanks, AK 99775, USA
- International Arctic Research Center, University of Alaska, Fairbanks, AK 99775, USA
- School of Geography, University of Southampton, UK
- College of Natural Sciences, University of Alaska, Fairbanks, AK 99775, USA
- Geophysical Institute, University of Alaska, Fairbanks, AK 99775, USA
| | - F. S. Chapin
- Water and Environmental Research Center, University of Alaska, Fairbanks, AK 99775, USA
- International Arctic Research Center, University of Alaska, Fairbanks, AK 99775, USA
- School of Geography, University of Southampton, UK
- College of Natural Sciences, University of Alaska, Fairbanks, AK 99775, USA
- Geophysical Institute, University of Alaska, Fairbanks, AK 99775, USA
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Walter KM, Zimov SA, Chanton JP, Verbyla D, Chapin FS. Methane bubbling from Siberian thaw lakes as a positive feedback to climate warming. Nature 2006; 443:71-5. [PMID: 16957728 DOI: 10.1038/nature05040] [Citation(s) in RCA: 198] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2005] [Accepted: 07/03/2006] [Indexed: 11/08/2022]
Abstract
Large uncertainties in the budget of atmospheric methane, an important greenhouse gas, limit the accuracy of climate change projections. Thaw lakes in North Siberia are known to emit methane, but the magnitude of these emissions remains uncertain because most methane is released through ebullition (bubbling), which is spatially and temporally variable. Here we report a new method of measuring ebullition and use it to quantify methane emissions from two thaw lakes in North Siberia. We show that ebullition accounts for 95 per cent of methane emissions from these lakes, and that methane flux from thaw lakes in our study region may be five times higher than previously estimated. Extrapolation of these fluxes indicates that thaw lakes in North Siberia emit 3.8 teragrams of methane per year, which increases present estimates of methane emissions from northern wetlands (< 6-40 teragrams per year; refs 1, 2, 4-6) by between 10 and 63 per cent. We find that thawing permafrost along lake margins accounts for most of the methane released from the lakes, and estimate that an expansion of thaw lakes between 1974 and 2000, which was concurrent with regional warming, increased methane emissions in our study region by 58 per cent. Furthermore, the Pleistocene age (35,260-42,900 years) of methane emitted from hotspots along thawing lake margins indicates that this positive feedback to climate warming has led to the release of old carbon stocks previously stored in permafrost.
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Affiliation(s)
- K M Walter
- Institute of Arctic Biology, University of Alaska Fairbanks, Alaska 99775, USA.
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Chapin FS, Callaghan TV, Bergeron Y, Fukuda M, Johnstone JF, Juday G, Zimov SA. Global change and the boreal forest: thresholds, shifting states or gradual change? Ambio 2004; 33:361-5. [PMID: 15387075 DOI: 10.1579/0044-7447-33.6.361] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Changes in boreal climate of the magnitude projected for the 21st century have always caused vegetation changes large enough to be societally important. However, the rates and patterns of vegetation change are difficult to predict. We review evidence suggesting that these vegetation changes may be gradual at the northern forest limit or where seed dispersal limits species distribution. However, forest composition may be quite resilient to climate change in the central portions of a species range until some threshold is surpassed. At this point, changes can be rapid and unexpected, often causing a switch to very different ecosystem types. Many of these triggers for change are amenable to management, suggesting that our choice of policies in the coming decades will substantially influence the ecological and societal consequences of current climatic change.
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Affiliation(s)
- F Stuart Chapin
- Institute of Arctic Biology, University of Alaska, Fairbanks 99775, USA.
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Chapin FS, Mcguire AD, Randerson J, Pielke R, Baldocchi D, Hobbie SE, Roulet N, Eugster W, Kasischke E, Rastetter EB, Zimov SA, Running SW. Arctic and boreal ecosystems of western North America as components of the climate system. Glob Chang Biol 2000; 6:211-223. [PMID: 35026938 DOI: 10.1046/j.1365-2486.2000.06022.x] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Synthesis of results from several Arctic and boreal research programmes provides evidence for the strong role of high-latitude ecosystems in the climate system. Average surface air temperature has increased 0.3 °C per decade during the twentieth century in the western North American Arctic and boreal forest zones. Precipitation has also increased, but changes in soil moisture are uncertain. Disturbance rates have increased in the boreal forest; for example, there has been a doubling of the area burned in North America in the past 20 years. The disturbance regime in tundra may not have changed. Tundra has a 3-6-fold higher winter albedo than boreal forest, but summer albedo and energy partitioning differ more strongly among ecosystems within either tundra or boreal forest than between these two biomes. This indicates a need to improve our understanding of vegetation dynamics within, as well as between, biomes. If regional surface warming were to continue, changes in albedo and energy absorption would likely act as a positive feedback to regional warming due to earlier melting of snow and, over the long term, the northward movement of treeline. Surface drying and a change in dominance from mosses to vascular plants would also enhance sensible heat flux and regional warming in tundra. In the boreal forest of western North America, deciduous forests have twice the albedo of conifer forests in both winter and summer, 50-80% higher evapotranspiration, and therefore only 30-50% of the sensible heat flux of conifers in summer. Therefore, a warming-induced increase in fire frequency that increased the proportion of deciduous forests in the landscape, would act as a negative feedback to regional warming. Changes in thermokarst and the aerial extent of wetlands, lakes, and ponds would alter high-latitude methane flux. There is currently a wide discrepancy among estimates of the size and direction of CO2 flux between high-latitude ecosystems and the atmosphere. These discrepancies relate more strongly to the approach and assumptions for extrapolation than to inconsistencies in the underlying data. Inverse modelling from atmospheric CO2 concentrations suggests that high latitudes are neutral or net sinks for atmospheric CO2 , whereas field measurements suggest that high latitudes are neutral or a net CO2 source. Both approaches rely on assumptions that are difficult to verify. The most parsimonious explanation of the available data is that drying in tundra and disturbance in boreal forest enhance CO2 efflux. Nevertheless, many areas of both tundra and boreal forests remain net sinks due to regional variation in climate and local variation in topographically determined soil moisture. Improved understanding of the role of high-latitude ecosystems in the climate system requires a concerted research effort that focuses on geographical variation in the processes controlling land-atmosphere exchange, species composition, and ecosystem structure. Future studies must be conducted over a long enough time-period to detect and quantify ecosystem feedbacks.
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Affiliation(s)
- F S Chapin
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775, USA
| | - A D Mcguire
- US Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit, University of Alaska, Fairbanks, AK 99775, USA
| | - J Randerson
- Department of Atmospheric Sciences, University of California, Berkeley, CA 94720, USA
| | - R Pielke
- Department of Atmospheric Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - D Baldocchi
- Atmospheric Turbulence and Diffusion Division, PO Box 2456, Oak Ridge, TN 37831, USA
| | - S E Hobbie
- Department of Ecology, Evolution, and Behaviour, University of Minnesota, St. Paul MN 55108, USA
| | - N Roulet
- Department of Geography, McGill University, Montreal, Quebec, Canada H3A 2K6
| | - W Eugster
- Institute of Geography, University of Bern, CH-3012 Bern, Switzerland
| | - E Kasischke
- ERIM International, Inc., PO Box 134008, Ann Arbor, MI 48113-4008, USA
| | - E B Rastetter
- Ecosystem Center, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - S A Zimov
- North-East Science Station, PO Box 18, Cherskii, Republic of Sakha (Yakutia), 678830 Russia, School of Forestry, University of Montana, Missoula, MT 59812-1063, USA
| | - S W Running
- North-East Science Station, PO Box 18, Cherskii, Republic of Sakha (Yakutia), 678830 Russia, School of Forestry, University of Montana, Missoula, MT 59812-1063, USA
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Zimov SA, Davidov SP, Zimova GM, Davidova AI, Chapin FS, Chapin MC, Reynolds JF. Contribution of disturbance to increasing seasonal amplitude of atmospheric CO2. Science 1999; 284:1973-6. [PMID: 10373112 DOI: 10.1126/science.284.5422.1973] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Recent increases in the seasonal amplitude of atmospheric carbon dioxide (CO2) at high latitudes suggest a widespread biospheric response to high-latitude warming. The seasonal amplitude of net ecosystem carbon exchange by northern Siberian ecosystems is shown to be greater in disturbed than undisturbed sites, due to increased summer influx and increased winter efflux. Increased disturbance could therefore contribute significantly to the amplified seasonal cycle of atmospheric carbon dioxide at high latitudes. Warm temperatures reduced summer carbon influx, suggesting that high-latitude warming, if it occurred, would be unlikely to increase seasonal amplitude of carbon exchange.
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Affiliation(s)
- SA Zimov
- North-East Scientific Station, Pacific Institute for Geography, Far-East Branch, Russian Academy of Sciences, Republic of Sakha, Yakutia, 678830 Cherskii, Russia. Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775-7000
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Zimov SA, Chuprynin VI, Oreshko AP, Chapin FS, Reynolds JF, Chapin MC. Steppe-Tundra Transition: A Herbivore-Driven Biome Shift at the End of the Pleistocene. Am Nat 1995. [DOI: 10.1086/285824] [Citation(s) in RCA: 276] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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