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Mineral Weathering and the Permafrost Carbon‐Climate Feedback
Author(s) -
Zolkos Scott,
Tank Suzanne E.,
Kokelj Steven V.
Publication year - 2018
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2018gl078748
Subject(s) - thermokarst , weathering , permafrost , carbonate , arctic , earth science , geology , carbon dioxide , carbon cycle , environmental chemistry , sulfuric acid , carbonic acid , ocean acidification , geochemistry , environmental science , climate change , oceanography , chemistry , ecosystem , ecology , inorganic chemistry , organic chemistry , biology
Permafrost thaw in the Arctic enables the biogeochemical transformation of vast stores of organic carbon into carbon dioxide (CO 2 ). This CO 2 release has significant implications for climate feedbacks, yet the potential counterbalance from CO 2 fixation via chemical weathering of minerals exposed by thawing permafrost is entirely unstudied. We show that thermokarst in the western Canadian Arctic can enable rapid weathering of carbonate tills, driven by sulfuric acid from sulfide oxidation. Unlike carbonic acid‐driven weathering, this caused significant and previously undocumented CO 2 production and outgassing in headwater streams. Increasing riverine solute fluxes correspond with long‐term intensification of thermokarst and reflect the regional predominance of sulfuric acid‐driven carbonate weathering. We conclude that thermokarst‐enhanced mineral weathering has potential to profoundly disrupt Arctic freshwater carbon cycling. While thermokarst and sulfuric acid‐driven carbonate weathering in the western Canadian Arctic amplify CO 2 release, regional variation in sulfide oxidation will moderate the effects on the permafrost carbon‐climate feedback.