Isotopic composition of ground ice, ebullition gases and thermokarst lake water, North America ...

Thermokarst lakes are thought to have been an important source of methane (CH4) during the last deglaciation when atmospheric CH4 concentrations increased rapidly. Here we demonstrate that meltwater from permafrost ice serves as an H source to CH4 production in thermokarst lakes, allowing for region...

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Bibliographic Details
Main Authors: Brosius, Laura Susan, Walter Anthony, Katey M, Grosse, Guido, Chanton, Jeffrey P, Farquharson, Louise M, Overduin, Pier Paul, Meyer, Hanno
Format: Article in Journal/Newspaper
Language:English
Published: PANGAEA 2012
Subjects:
Ice
IPY
Online Access:https://dx.doi.org/10.1594/pangaea.808037
https://doi.pangaea.de/10.1594/PANGAEA.808037
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Summary:Thermokarst lakes are thought to have been an important source of methane (CH4) during the last deglaciation when atmospheric CH4 concentrations increased rapidly. Here we demonstrate that meltwater from permafrost ice serves as an H source to CH4 production in thermokarst lakes, allowing for region-specific reconstructions of dD-CH4 emissions from Siberian and North American lakes. dD CH4 reflects regionally varying dD values of precipitation incorporated into ground ice at the time of its formation. Late Pleistocene-aged permafrost ground ice was the dominant H source to CH4 production in primary thermokarst lakes, whereas Holocene-aged permafrost ground ice contributed H to CH4 production in later generation lakes. We found that Alaskan thermokarst lake dD-CH4 was higher (-334 ± 17 per mil) than Siberian lake dD-CH4 (-381 ± 18 per mil). Weighted mean dD CH4 values for Beringian lakes ranged from -385 per mil to -382 per mil over the deglacial period. Bottom-up estimates suggest that Beringian thermokarst ... : Data extracted in the frame of a joint ICSTI/PANGAEA IPY effort, see http://doi.pangaea.de/10.1594/PANGAEA.150150 ...