Premium
Long‐term anoxia and release of ancient, labile carbon upon thaw of Pleistocene permafrost
Author(s) -
Ewing Stephanie A.,
O'Donnell Jonathan A.,
Aiken George R.,
Butler Kenna,
Butman David,
WindhamMyers Lisamarie,
Kanevskiy Mikhail Z.
Publication year - 2015
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 - 10.1002/2015gl066296
Subject(s) - permafrost , dissolved organic carbon , context (archaeology) , environmental chemistry , environmental science , total organic carbon , ammonium , isotopes of carbon , δ13c , dissolution , geology , stable isotope ratio , hydrology (agriculture) , chemistry , oceanography , paleontology , geotechnical engineering , organic chemistry , physics , quantum mechanics
The fate of permafrost carbon upon thaw will drive feedbacks to climate warming. Here we consider the character and context of dissolved organic carbon (DOC) in yedoma permafrost cores from up to 20 m depth in central Alaska. We observed high DOC concentrations (4 to 129 mM) and consistent low molecular weight organic acid concentrations in three cores. We estimate a DOC production rate of 12 µmol DOC m −2 yr −1 based on model ages of up to ~200 kyr derived from uranium isotopes. Acetate C accounted for 24 ± 1% of DOC in all samples. This proportion suggests long‐term anaerobiosis and is likely to influence thaw outcomes due to biolability of acetate upon release in many environments. The combination of uranium isotopes, ammonium concentrations, and calcium concentrations explained 86% of the variation in thaw water DOC concentrations, suggesting that DOC production may be related to both reducing conditions and mineral dissolution over time.