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Short and Long-Term Controls on Active Layer and Permafrost Carbon Turnover Across the Arctic

Faucherre, Samuel; Jørgensen, Christian Juncher; Blok, Daan LU ; Weiss, Niels; Siewert, Matthias Benjamin; Bang-Andreasen, Toke; Hugelius, Gustaf; Kuhry, Peter and Elberling, Bo (2018) In Journal of Geophysical Research: Biogeosciences
Abstract

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 (Closs) five times during a 1 year incubation. The... (More)

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 (Closs) five times during a 1 year incubation. The incubated material consisted of near-surface active layer (ALNS), subsurface active layer (ALSS), peat, and permafrost samples. Samples were analyzed for carbon, nitrogen, water content, δ13C, δ15N, and dry bulk density (DBD). While no significant differences were observed between total ALSS and permafrost Closs over 1 year incubation (2.3 ± 2.4% and 2.5 ± 1.5% Closs, respectively), ALNS samples showed higher Closs (7.9 ± 4.2%). DBD was the best explanatory parameter for active layer Closs across sites. Additionally, results of permafrost samples show that C:N ratio can be used to characterize initial Closs between sites. This data set on the influence of abiotic parameter on microbial SOM decomposition can improve model simulations of Arctic soil CO2 production by providing representative mean values of CO2 production rates and identifying standard parameters or proxies for upscaling potential CO2 production from site to regional scales.

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author
organization
publishing date
type
Contribution to journal
publication status
epub
subject
keywords
Carbon, Carbon dioxide, Carbon mineralization, Decomposition, Permafrost
in
Journal of Geophysical Research: Biogeosciences
publisher
American Geophysical Union
external identifiers
  • scopus:85042108000
ISSN
2169-8953
DOI
10.1002/2017JG004069
language
English
LU publication?
yes
id
fb38887d-1e01-468f-84ef-d7a2b6dc62c1
date added to LUP
2018-03-07 11:52:35
date last changed
2018-05-29 12:13:17
@article{fb38887d-1e01-468f-84ef-d7a2b6dc62c1,
  abstract     = {<p>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<sub>loss</sub>) five times during a 1 year incubation. The incubated material consisted of near-surface active layer (AL<sub>NS</sub>), subsurface active layer (AL<sub>SS</sub>), peat, and permafrost samples. Samples were analyzed for carbon, nitrogen, water content, δ<sup>13</sup>C, δ<sup>15</sup>N, and dry bulk density (DBD). While no significant differences were observed between total AL<sub>SS</sub> and permafrost C<sub>loss</sub> over 1 year incubation (2.3 ± 2.4% and 2.5 ± 1.5% C<sub>loss</sub>, respectively), AL<sub>NS</sub> samples showed higher C<sub>loss</sub> (7.9 ± 4.2%). DBD was the best explanatory parameter for active layer C<sub>loss</sub> across sites. Additionally, results of permafrost samples show that C:N ratio can be used to characterize initial C<sub>loss</sub> between sites. This data set on the influence of abiotic parameter on microbial SOM decomposition can improve model simulations of Arctic soil CO<sub>2</sub> production by providing representative mean values of CO<sub>2</sub> production rates and identifying standard parameters or proxies for upscaling potential CO<sub>2</sub> production from site to regional scales.</p>},
  author       = {Faucherre, Samuel and Jørgensen, Christian Juncher and Blok, Daan and Weiss, Niels and Siewert, Matthias Benjamin and Bang-Andreasen, Toke and Hugelius, Gustaf and Kuhry, Peter and Elberling, Bo},
  issn         = {2169-8953},
  keyword      = {Carbon,Carbon dioxide,Carbon mineralization,Decomposition,Permafrost},
  language     = {eng},
  month        = {02},
  publisher    = {American Geophysical Union},
  series       = {Journal of Geophysical Research: Biogeosciences},
  title        = {Short and Long-Term Controls on Active Layer and Permafrost Carbon Turnover Across the Arctic},
  url          = {http://dx.doi.org/10.1002/2017JG004069},
  year         = {2018},
}