Details
| Original language | English |
|---|---|
| Pages (from-to) | 3401-3415 |
| Number of pages | 15 |
| Journal | Global change biology |
| Volume | 24 |
| Issue number | 8 |
| Early online date | 18 May 2018 |
| Publication status | Published - 3 Jul 2018 |
Abstract
Climate change in Arctic ecosystems fosters permafrost thaw and makes massive amounts of ancient soil organic carbon (OC) available to microbial breakdown. However, fractions of the organic matter (OM) may be protected from rapid decomposition by their association with minerals. Little is known about the effects of mineral-organic associations (MOA) on the microbial accessibility of OM in permafrost soils and it is not clear which factors control its temperature sensitivity. In order to investigate if and how permafrost soil OC turnover is affected by mineral controls, the heavy fraction (HF) representing mostly MOA was obtained by density fractionation from 27 permafrost soil profiles of the Siberian Arctic. In parallel laboratory incubations, the unfractionated soils (bulk) and their HF were comparatively incubated for 175 days at 5 and 15°C. The HF was equivalent to 70 ± 9% of the bulk CO2 respiration as compared to a share of 63 ± 1% of bulk OC that was stored in the HF. Significant reduction of OC mineralization was found in all treatments with increasing OC content of the HF (HF-OC), clay-size minerals and Fe or Al oxyhydroxides. Temperature sensitivity (Q10) decreased with increasing soil depth from 2.4 to 1.4 in the bulk soil and from 2.9 to 1.5 in the HF. A concurrent increase in the metal-to-HF-OC ratios with soil depth suggests a stronger bonding of OM to minerals in the subsoil. There, the younger 14C signature in CO2 than that of the OC indicates a preferential decomposition of the more recent OM and the existence of a MOA fraction with limited access of OM to decomposers. These results indicate strong mineral controls on the decomposability of OM after permafrost thaw and on its temperature sensitivity. Thus, we here provide evidence that OM temperature sensitivity can be attenuated by MOA in permafrost soils.
Keywords
- carbon mineralization, incubation, mineral-organic association, permafrost soils, radiocarbon, temperature sensitivity
ASJC Scopus subject areas
- Environmental Science(all)
- Global and Planetary Change
- Environmental Science(all)
- Environmental Chemistry
- Environmental Science(all)
- Ecology
- Environmental Science(all)
Sustainable Development Goals
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In: Global change biology, Vol. 24, No. 8, 03.07.2018, p. 3401-3415.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Temperature response of permafrost soil carbon is attenuated by mineral protection
AU - Gentsch, Norman
AU - Wild, Birgit
AU - Mikutta, Robert
AU - Čapek, Petr
AU - Diáková, Katka
AU - Schrumpf, Marion
AU - Turner, Stephanie
AU - Minnich, Cynthia
AU - Schaarschmidt, Frank
AU - Shibistova, Olga
AU - Schnecker, Jörg
AU - Urich, Tim
AU - Gittel, Antje
AU - Šantrůčková, Hana
AU - Bárta, Jiři
AU - Lashchinskiy, Nikolay
AU - Fuß, Roland
AU - Richter, Andreas
AU - Guggenberger, Georg
N1 - © 2018 John Wiley & Sons Ltd
PY - 2018/7/3
Y1 - 2018/7/3
N2 - Climate change in Arctic ecosystems fosters permafrost thaw and makes massive amounts of ancient soil organic carbon (OC) available to microbial breakdown. However, fractions of the organic matter (OM) may be protected from rapid decomposition by their association with minerals. Little is known about the effects of mineral-organic associations (MOA) on the microbial accessibility of OM in permafrost soils and it is not clear which factors control its temperature sensitivity. In order to investigate if and how permafrost soil OC turnover is affected by mineral controls, the heavy fraction (HF) representing mostly MOA was obtained by density fractionation from 27 permafrost soil profiles of the Siberian Arctic. In parallel laboratory incubations, the unfractionated soils (bulk) and their HF were comparatively incubated for 175 days at 5 and 15°C. The HF was equivalent to 70 ± 9% of the bulk CO2 respiration as compared to a share of 63 ± 1% of bulk OC that was stored in the HF. Significant reduction of OC mineralization was found in all treatments with increasing OC content of the HF (HF-OC), clay-size minerals and Fe or Al oxyhydroxides. Temperature sensitivity (Q10) decreased with increasing soil depth from 2.4 to 1.4 in the bulk soil and from 2.9 to 1.5 in the HF. A concurrent increase in the metal-to-HF-OC ratios with soil depth suggests a stronger bonding of OM to minerals in the subsoil. There, the younger 14C signature in CO2 than that of the OC indicates a preferential decomposition of the more recent OM and the existence of a MOA fraction with limited access of OM to decomposers. These results indicate strong mineral controls on the decomposability of OM after permafrost thaw and on its temperature sensitivity. Thus, we here provide evidence that OM temperature sensitivity can be attenuated by MOA in permafrost soils.
AB - Climate change in Arctic ecosystems fosters permafrost thaw and makes massive amounts of ancient soil organic carbon (OC) available to microbial breakdown. However, fractions of the organic matter (OM) may be protected from rapid decomposition by their association with minerals. Little is known about the effects of mineral-organic associations (MOA) on the microbial accessibility of OM in permafrost soils and it is not clear which factors control its temperature sensitivity. In order to investigate if and how permafrost soil OC turnover is affected by mineral controls, the heavy fraction (HF) representing mostly MOA was obtained by density fractionation from 27 permafrost soil profiles of the Siberian Arctic. In parallel laboratory incubations, the unfractionated soils (bulk) and their HF were comparatively incubated for 175 days at 5 and 15°C. The HF was equivalent to 70 ± 9% of the bulk CO2 respiration as compared to a share of 63 ± 1% of bulk OC that was stored in the HF. Significant reduction of OC mineralization was found in all treatments with increasing OC content of the HF (HF-OC), clay-size minerals and Fe or Al oxyhydroxides. Temperature sensitivity (Q10) decreased with increasing soil depth from 2.4 to 1.4 in the bulk soil and from 2.9 to 1.5 in the HF. A concurrent increase in the metal-to-HF-OC ratios with soil depth suggests a stronger bonding of OM to minerals in the subsoil. There, the younger 14C signature in CO2 than that of the OC indicates a preferential decomposition of the more recent OM and the existence of a MOA fraction with limited access of OM to decomposers. These results indicate strong mineral controls on the decomposability of OM after permafrost thaw and on its temperature sensitivity. Thus, we here provide evidence that OM temperature sensitivity can be attenuated by MOA in permafrost soils.
KW - carbon mineralization
KW - incubation
KW - mineral-organic association
KW - permafrost soils
KW - radiocarbon
KW - temperature sensitivity
UR - http://www.scopus.com/inward/record.url?scp=85047829376&partnerID=8YFLogxK
U2 - 10.1111/gcb.14316
DO - 10.1111/gcb.14316
M3 - Article
C2 - 29774972
AN - SCOPUS:85047829376
VL - 24
SP - 3401
EP - 3415
JO - Global change biology
JF - Global change biology
SN - 1354-1013
IS - 8
ER -