A shift of thermokarst lakes from carbon sources to sinks during the Holocene epoch

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.

[1]  J. Kalff,et al.  Benthic Photosynthesis and Respiration in Char Lake , 1974 .

[2]  Guido Grosse,et al.  The use of CORONA images in remote sensing of periglacial geomorphology: an illustration from the NE Siberian coast , 2005 .

[3]  Jaromír Demek,et al.  Thermokarst in Siberia and Its Influence on the Development of Lowland Relief , 1970, Quaternary Research.

[4]  Guido Grosse,et al.  Distribution of late Pleistocene ice-rich syngenetic permafrost of the Yedoma Suite in east and central Siberia, Russia , 2013 .

[5]  C. Buck,et al.  IntCal09 and Marine09 Radiocarbon Age Calibration Curves, 0–50,000 Years cal BP , 2009, Radiocarbon.

[6]  J. Houghton,et al.  Climate change 2001 : the scientific basis , 2001 .

[7]  J. Finlay,et al.  Biogeochemical processes in high-latitude lakes and rivers , 2009 .

[8]  Sarah E. Gergel,et al.  Relative impacts of disturbance and temperature: persistent changes in microenvironment and vegetation in retrogressive thaw slumps , 2009 .

[9]  J. Canadell,et al.  Soil organic carbon pools in the northern circumpolar permafrost region , 2009 .

[10]  Quan Hua,et al.  14CH4 Measurements in Greenland Ice: Investigating Last Glacial Termination CH4 Sources , 2009, Science.

[11]  G. Henderson,et al.  Speleothems Reveal 500,000-Year History of Siberian Permafrost , 2013, Science.

[12]  F. Chapin,et al.  Permafrost and the Global Carbon Budget , 2006, Science.

[13]  M. Hinderer,et al.  Long‐term carbon burial in European lakes: Analysis and estimate , 2011 .

[14]  Guido Grosse,et al.  Application of Landsat-7 satellite data and a DEM for the quantification of thermokarst-affected terrain types in the periglacial Lena–Anabar coastal lowland , 2006 .

[15]  Guido Grosse,et al.  Peat accumulation in drained thermokarst lake basins in continuous, ice-rich permafrost, northern Seward Peninsula, Alaska , 2011 .

[16]  Katey Walter Anthony,et al.  Constraining spatial variability of methane ebullition seeps in thermokarst lakes using point process models , 2013 .

[17]  Corinne Le Quéré,et al.  Climate Change 2013: The Physical Science Basis , 2013 .

[18]  Walter E. Dean,et al.  Determination of carbonate and organic matter in calcareous sediments and sedimentary rocks by loss on ignition; comparison with other methods , 1974 .

[19]  T. Prowse,et al.  Effects of retrogressive permafrost thaw slumping on sediment chemistry and submerged macrophytes in Arctic tundra lakes , 2010 .

[20]  M. Weintraub Biological Phosphorus Cycling in Arctic and Alpine Soils , 2011 .

[21]  T. Péwé,et al.  Radiocarbon Dates and Late-Quaternary Stratigraphy from Mamontova Gora, Unglaciated Central Yakutia, Siberia, U.S.S.R. , 1977, Quaternary Research.

[22]  Anne Morgenstern,et al.  Thermokarst and thermal erosion: Degradation of Siberian ice-rich permafrost , 2012 .

[23]  M. Noguer,et al.  Climate change 2001: The scientific basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change , 2002 .

[24]  Lee Slater,et al.  Carbon Cycling in Northern Peatlands , 2009 .

[25]  E. S. Melnikov,et al.  The Circumpolar Arctic vegetation map , 2005 .

[26]  D. Walker,et al.  Loess Ecosystems of Northern Alaska: Regional Gradient and Toposequence at Prudhoe Bay , 1991 .

[27]  A. Hershey Effects of Predatory Sculpin on the Chironomid Communities in an Arctic Lake , 1985 .

[28]  Masami Fukuda,et al.  Thermokarst as a short‐term permafrost disturbance, Central Yakutia , 2004 .

[29]  J. Canadell,et al.  The Northern Circumpolar Soil Carbon Database: spatially distributed datasets of soil coverage and soil carbon storage in the northern permafrost regions , 2012 .

[30]  Guido Grosse,et al.  Spatial analyses of thermokarst lakes and basins in Yedoma landscapes of the Lena Delta , 2011 .

[31]  Louette R. Johnson Lutjens Research , 2006 .

[32]  Guido Grosse,et al.  Land cover classification of tundra environments in the Arctic Lena Delta based on Landsat 7 ETM+ data and its application for upscaling of methane emissions , 2009 .

[33]  P. Grootes,et al.  Late Quaternary ice-rich permafrost sequences as a paleoenvironmental archive for the Laptev Sea Region in northern Siberia , 2002 .

[34]  Jeffrey N. Houser,et al.  Water color affects the stratification, surface temperature, heat content, and mean epilimnetic irradiance of small lakes , 2006 .

[35]  Corinne Le Quéré,et al.  Climate Change 2013: The Physical Science Basis , 2013 .

[36]  Guido Grosse,et al.  Modern thermokarst lake dynamics in the continuous permafrost zone, northern Seward Peninsula, Alaska , 2011 .

[37]  G. Grosse,et al.  Weichselian and Holocene palaeoenvironmental history of the Bol'shoy Lyakhovsky Island, New Siberian Archipelago, Arctic Siberia , 2009 .

[38]  Mikhail Kanevskiy,et al.  Cryostratigraphy of late Pleistocene syngenetic permafrost (yedoma) in northern Alaska, Itkillik River exposure , 2011, Quaternary Research.

[39]  Corinne Le Quéré,et al.  An efficient and accurate representation of complex oceanic and biospheric models of anthropogenic carbon uptake , 1996 .

[40]  André Berger,et al.  Insolation values for the climate of the last 10 , 1991 .

[41]  J. Finlay,et al.  Long-term effects of PO4 fertilization on the distribution of bryophytes in an arctic river , 1994 .

[42]  Katrin J. Meissner,et al.  Reduction in areal extent of high-latitude wetlands in response to permafrost thaw , 2011 .

[43]  G. Grosse,et al.  The deep permafrost carbon pool of the Yedoma region in Siberia and Alaska , 2013, Geophysical research letters.

[44]  R. Vaikmae Oxygen isotope composition of ground ice: Application to paleogeocryological reconstructions: Y. Vasil'chuk. Volumes 1 and 2, The Russian Academy of Science, 1992 (in Russian) , 1994 .

[45]  B. Olesen,et al.  Growth Rate of an Aquatic Bryophyte ( Warnstorfia fluitans (Hedw.) Loeske) from a High Arctic Lake: Effect of Nutrient Concentration , 2010 .

[46]  K. W. Anthony,et al.  Simulating the decadal‐ to millennial‐scale dynamics of morphology and sequestered carbon mobilization of two thermokarst lakes in NW Alaska , 2012 .

[47]  Guido Grosse,et al.  Using the deuterium isotope composition of permafrost meltwater to constrain thermokarst lake contributions to atmospheric CH4 during the last deglaciation , 2012 .

[48]  F. Chapin,et al.  Thermokarst Lakes as a Source of Atmospheric CH4 During the Last Deglaciation , 2007, Science.

[49]  John M. Melack,et al.  Lakes and reservoirs as regulators of carbon cycling and climate , 2009 .

[50]  J. M. Bremner,et al.  A simple titrimetric method for determination of inorganic carbon in soils , 1972 .

[51]  G. Grosse,et al.  Periglacial landscape evolution and environmental changes of Arctic lowland areas for the last 60 000 years (western Laptev Sea coast, Cape Mamontov Klyk) , 2008 .

[52]  E. Maltby,et al.  Carbon dynamics in peatlands and other wetland soils regional and global perspectives , 1993 .

[53]  N. Rose,et al.  A whole-basin, mass-balance approach to paleolimnology , 2013, Journal of Paleolimnology.

[54]  R. D. Dietz,et al.  Land-use change, not climate, controls organic carbon burial in lakes , 2013, Proceedings of the Royal Society B: Biological Sciences.

[55]  Alexandra Veremeeva,et al.  Modern tundra landscapes of the Kolyma Lowland and their evolution in the Holocene , 2009 .

[56]  Steve Frolking,et al.  Holocene radiative forcing impact of northern peatland carbon accumulation and methane emissions , 2006 .

[57]  Warwick F. Vincent,et al.  Polar Lakes and Rivers - Limnology of Arctic and Antarctic Aquatic Ecosystems , 2008 .

[58]  E. Schuur,et al.  Fossil organic matter characteristics in permafrost deposits of the northeast Siberian Arctic , 2011 .

[59]  A A Velichko,et al.  Siberian Peatlands a Net Carbon Sink and Global Methane Source Since the Early Holocene , 2004, Science.

[60]  R Core Team,et al.  R: A language and environment for statistical computing. , 2014 .

[61]  Yves T. Prairie,et al.  Long‐term C accumulation and total C stocks in boreal lakes in northern Québec , 2012 .

[62]  F. Chapin,et al.  Methane bubbling from Siberian thaw lakes as a positive feedback to climate warming , 2006, Nature.

[63]  Laurence C. Smith,et al.  A first pan‐Arctic assessment of the influence of glaciation, permafrost, topography and peatlands on northern hemisphere lake distribution , 2007 .

[64]  Vladimir E. Romanovsky,et al.  Thermal state of permafrost in Russia , 2010 .

[65]  D. Lawrence,et al.  Diagnosing Present and Future Permafrost from Climate Models , 2012 .