Temperature response of permafrost soil carbon is attenuated by mineral protection.

Autor: Gentsch N; Institute of Soil Science, Leibniz Universität Hannover, Hannover, Germany., Wild B; Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria.; Austrian Polar Research Institute, Vienna, Austria.; Department of Environmental Science and Analytical Chemistry, Stockholm University, Stockholm, Sweden.; Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden., Mikutta R; Institute of Soil Science, Leibniz Universität Hannover, Hannover, Germany.; Soil Science and Soil Protection, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany., Čapek P; Department of Ecosystems Biology, University of South Bohemia, České Budéjovice, Czech Republic., Diáková K; Department of Ecosystems Biology, University of South Bohemia, České Budéjovice, Czech Republic., Schrumpf M; Max Planck Institute for Biogeochemistry, Jena, Germany., Turner S; Federal Institute for Geosciences and Natural Resources (BGR), Hannover, Germany., Minnich C; Institute of Soil Science, Leibniz Universität Hannover, Hannover, Germany.; Soil Ecology, University of Bayreuth, Bayreuth, Germany., Schaarschmidt F; Institute of Biostatistics, Leibniz Universität Hannover, Hannover, Germany., Shibistova O; Institute of Soil Science, Leibniz Universität Hannover, Hannover, Germany.; V.N. Sukachev Institute of Forest, Siberian Branch of Russian Academy of Sciences, Krasnoyarsk, Russia., Schnecker J; Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria.; Austrian Polar Research Institute, Vienna, Austria.; Department of Natural Resources and the Environment, University of New Hampshire, Durham, New Hampshire., Urich T; Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria.; Institute of Microbiology, Ernst-Moritz-Arndt University, Greifswald, Germany., Gittel A; Department of Biology, Centre for Geobiology, University of Bergen, Bergen, Norway.; Department of Bioscience, Centre for Geomicrobiology, Aarhus, Denmark., Šantrůčková H; Department of Ecosystems Biology, University of South Bohemia, České Budéjovice, Czech Republic., Bárta J; Department of Ecosystems Biology, University of South Bohemia, České Budéjovice, Czech Republic., Lashchinskiy N; Central Siberian Botanical Garden, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia., Fuß R; Thünen Institute of Climate-Smart Agriculture, Braunschweig, Germany., Richter A; Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria.; Austrian Polar Research Institute, Vienna, Austria., Guggenberger G; Institute of Soil Science, Leibniz Universität Hannover, Hannover, Germany.; V.N. Sukachev Institute of Forest, Siberian Branch of Russian Academy of Sciences, Krasnoyarsk, Russia.
Jazyk: angličtina
Zdroj: Global change biology [Glob Chang Biol] 2018 Aug; Vol. 24 (8), pp. 3401-3415. Date of Electronic Publication: 2018 Jun 01.
DOI: 10.1111/gcb.14316
Abstrakt: 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 CO 2 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 14 C signature in CO 2 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.
(© 2018 John Wiley & Sons Ltd.)
Databáze: MEDLINE
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