Кл.слова (ненормированные):
13C enrichment of soil profile -- Anaplerotic enzymes -- Carboxylase genes -- Microbial community composition -- Permafrost soils -- Biogeochemistry -- Biological materials -- Carbon -- Carbon dioxide -- Ecosystems -- Enzymes -- Fatty acids -- Genes -- Metabolism -- Microorganisms -- Organic carbon -- Organic compounds -- Permafrost -- Phospholipids -- Soils -- Anaplerotic enzymes -- Microbial community composition -- Microbial metabolism -- Net primary productivity -- Phospholipid fatty acids -- Regulatory functions -- Soil organic matters -- Soil profiles -- Soil surveys
Аннотация: The occurrence of dark fixation of CO2 by heterotrophic microorganisms in soil is generally accepted, but its importance for microbial metabolism and soil organic carbon (C) sequestration is unknown, especially under C-limiting conditions. To fill this knowledge gap, we measured dark 13CO2 incorporation into soil organic matter and conducted a 13C-labelling experiment to follow the 13C incorporation into phospholipid fatty acids as microbial biomass markers across soil profiles of four tundra ecosystems in the northern circumpolar region, where net primary productivity and thus soil C inputs are low. We further determined the abundance of various carboxylase genes and identified their microbial origin with metagenomics. The microbial capacity for heterotrophic CO2 fixation was determined by measuring the abundance of carboxylase genes and the incorporation of 13C into soil C following the augmentation of bioavailable C sources. We demonstrate that dark CO2 fixation occurred ubiquitously in arctic tundra soils, with increasing importance in deeper soil horizons, presumably due to increasing C limitation with soil depth. Dark CO2 fixation accounted on average for 0.4, 1.0, 1.1, and 16% of net respiration in the organic, cryoturbated organic, mineral and permafrost horizons, respectively. Genes encoding anaplerotic enzymes of heterotrophic microorganisms comprised the majority of identified carboxylase genes. The genetic potential for dark CO2 fixation was spread over a broad taxonomic range. The results suggest important regulatory function of CO2 fixation in C limited conditions. The measurements were corroborated by modeling the long-term impact of dark CO2 fixation on soil organic matter. Our results suggest that increasing relative CO2 fixation rates in deeper soil horizons play an important role for soil internal C cycling and can, at least in part, explain the isotopic enrichment with soil depth. © 2018 Elsevier Ltd
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Держатели документа:
University of South Bohemia, Department of Ecosystems Biology, Ceske Budejovice, Czech Republic
Institute of Microbiology, Ernst-Moritz-Arndt University Greifswald, Greifswald, Germany
Department of Physical Geography, Stockholm University, Sweden
Austrian Polar Research Institute, Vienna, Austria
Department of Environmental Science, University of Eastern Finland, PO Box 1627, Kuopio, Finland
Leibniz Universitat Hannover, Institut fur Bodenkunde, Hannover, Germany
University of Bergen, Centre for Geobiology, Department of Biology, Bergen, Norway
Siberian Branch of Russian Academy of Sciences, Central Siberian Botanical Garden, Novosibirsk, Russian Federation
Soil Science and Soil Protection, Martin Luther University Halle-Wittenberg, Germany
University of Vienna, Department of Ecogenomics and Systems Biology, Division of Archaea Biology and Ecogenomics, Vienna, Austria
University of Vienna, Department of Microbiology and Ecosystem Science, Division of Terrestrial Ecosystem Research, Vienna, Austria
Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH, United States
Laboratory of Food Biotechnology, ETH Zurich, Institute of Food, Nutrition and Health, Schmelzbergstrasse 7, Zurich, Switzerland
Siberian Branch of Russian Academy of Sciences, VN Sukachev Institute of Forest, Krasnoyarsk, Russian Federation
Department of Environmental Science and Analytical Chemistry, Stockholm University, Stockholm, Sweden
Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
Доп.точки доступа:
Santruckova, H.; Kotas, P.; Barta, J.; Urich, T.; Capek, P.; Palmtag, J.; Eloy Alves, R. J.; Biasi, C.; Diakova, K.; Gentsch, N.; Gittel, A.; Guggenberger, G.; Hugelius, G.; Lashchinsky, N.; Martikainen, P. J.; Mikutta, R.; Schleper, C.; Schnecker, J.; Schwab, C.; Shibistova, O.; Wild, B.; Richter, A.