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Short and Long‐Term Controls on Active Layer and Permafrost Carbon Turnover Across the Arctic
Author(s) -
Faucherre Samuel,
Jørgensen Christian Juncher,
Blok Daan,
Weiss Niels,
Siewert Matthias Benjamin,
BangAndreasen Toke,
Hugelius Gustaf,
Kuhry Peter,
Elberling Bo
Publication year - 2018
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1002/2017jg004069
Subject(s) - permafrost , soil carbon , carbon fibers , arctic , environmental science , active layer , decomposition , soil water , nitrogen , soil science , soil organic matter , total organic carbon , environmental chemistry , chemistry , ecology , layer (electronics) , materials science , thin film transistor , organic chemistry , biology , composite number , composite material
Decomposition of soil organic matter (SOM) in permafrost terrain and the production of greenhouse gases is a key factor for understanding climate change‐carbon feedbacks. Previous studies have shown that SOM decomposition is mostly controlled by soil temperature, soil moisture, and carbon‐nitrogen ratio (C:N). However, focus has generally been on site‐specific processes and little is known about variations in the controls on SOM decomposition across Arctic sites. For assessing SOM decomposition, we retrieved 241 samples from 101 soil profiles across three contrasting Arctic regions and incubated them in the laboratory under aerobic conditions. We assessed soil carbon losses (C loss ) five times during a 1 year incubation. The incubated material consisted of near‐surface active layer (AL NS ), subsurface active layer (AL SS ), peat, and permafrost samples. Samples were analyzed for carbon, nitrogen, water content, δ 13 C, δ 15 N, and dry bulk density (DBD). While no significant differences were observed between total AL SS and permafrost C loss over 1 year incubation (2.3 ± 2.4% and 2.5 ± 1.5% C loss , respectively), AL NS samples showed higher C loss (7.9 ± 4.2%). DBD was the best explanatory parameter for active layer C loss across sites. Additionally, results of permafrost samples show that C:N ratio can be used to characterize initial C loss between sites. This data set on the influence of abiotic parameter on microbial SOM decomposition can improve model simulations of Arctic soil CO 2 production by providing representative mean values of CO 2 production rates and identifying standard parameters or proxies for upscaling potential CO 2 production from site to regional scales.