Roles of Thermokarst Lakes in a Warming World

Permafrost covers a quarter of the northern hemisphere land surface and contains twice the amount of carbon that is currently present in the atmosphere. Future climate change is expected to reduce its near-surface cover by over 90% by the end of the 21st century, leading to thermokarst lake formatio...

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Bibliographic Details
Published in:Trends in microbiology (Regular ed.) 2020-09, Vol.28 (9), p.769-779
Main Authors: in 't Zandt, Michiel H., Liebner, Susanne, Welte, Cornelia U.
Format: Article
Language:English
Subjects:
Air temperature
Atmosphere
Carbon
Carbon dioxide
Carbon sources
Climate change
Global warming
Greenhouse effect
Greenhouse gases
Lakes
methane
methanogenesis
methanotrophy
Microorganisms
Northern Hemisphere
Permafrost
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Summary:Permafrost covers a quarter of the northern hemisphere land surface and contains twice the amount of carbon that is currently present in the atmosphere. Future climate change is expected to reduce its near-surface cover by over 90% by the end of the 21st century, leading to thermokarst lake formation. Thermokarst lakes are point sources of carbon dioxide and methane which release long-term carbon stocks into the atmosphere, thereby initiating a positive climate feedback potentially contributing up to a 0.39°C rise of surface air temperatures by 2300. This review describes the potential role of thermokarst lakes in a warming world and the microbial mechanisms that underlie their contributions to the global greenhouse gas budget. Thermokarst lakes form as a result of permafrost thaw in predominantly ice-rich yedoma deposits and are therefore an ecosystem that is rapidly expanding with the onset of climate change.Thermokarst lakes are net greenhouse gas sources as century-old carbon deposits become bioavailable and are mineralized to CO2 and CH4.CH4 is a more potent greenhouse gas than CO2. Changed dynamics will therefore disproportionately affect global warming.Methane emissions are the net result of methane production by methanogenesis and methane oxidation by aerobic bacteria or anaerobic archaea, with high levels of heterogeneity and intricate interactions.Future climate change will have disproportionate effects on the Arctic, which implies potentially strong consequences for future greenhouse gas fluxes and thaw progression.
ISSN:0966-842X
1878-4380
DOI:10.1016/j.tim.2020.04.002