High biolability of ancient permafrost carbon upon thaw

Ongoing climate warming in the Arctic will thaw permafrost and remobilize substantial terrestrial organic carbon (OC) pools. Around a quarter of northern permafrost OC resides in Siberian Yedoma deposits, the oldest form of permafrost carbon. However, our understanding of the degradation and fate of...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Vonk, Jorien, Mann, Paul, Davydov, Sergey, Davydova, Anna, Spencer, Robert, Schade, John, Sobczak, William, Zimov, Nikita, Zimov, Sergei, Bulygina, Ekaterina, Eglinton, Timothy, Holmes, Robert
Format: Article in Journal/Newspaper
Language:unknown
Published: Wiley-Blackwell 2013
Subjects:
C100 Biology
C500 Microbiology
C900 Others in Biological Sciences
F700 Ocean Sciences
Arctic
permafrost
Online Access:https://nrl.northumbria.ac.uk/id/eprint/13297/
https://doi.org/10.1002/grl.50348
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Summary:Ongoing climate warming in the Arctic will thaw permafrost and remobilize substantial terrestrial organic carbon (OC) pools. Around a quarter of northern permafrost OC resides in Siberian Yedoma deposits, the oldest form of permafrost carbon. However, our understanding of the degradation and fate of this ancient OC in coastal and fluvial environments still remains rudimentary. Here, we show that ancient dissolved OC (DOC, >21,000 14C years), the oldest DOC ever reported, is mobilized in stream waters draining Yedoma outcrops. Furthermore, this DOC is highly biolabile: 34 ± 0.8% was lost during a 14 day incubation under dark, oxygenated conditions at ambient river temperatures. Mixtures of Yedoma stream DOC with mainstem river and ocean waters, mimicking in situ mixing processes, also showed high DOC losses (14 days; 17 ± 0.8% to 33 ± 1.0%). This suggests that this exceptionally old DOC is among the most biolabile DOC in any previously reported contemporary river or stream in the Arctic.

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