["Ewing, Stephanie A","O'Donnell, Jonathan A","Aiken, George R","Butler, Kenna","Butman, David","Windham-Myers, Lisamarie","Kanevskiy, Mikhail Z"]2015-12-28期刊论文
(24)
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 20m depth in central Alaska. We observed high DOC concentrations (4 to 129mM) and consistent low molecular weight organic acid concentrations in three cores. We estimate a DOC production rate of 12 mu molDOCm(-2)yr(-1) based on model ages of up to similar to 200kyr derived from uranium isotopes. Acetate C accounted for 241% 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.
