Significance of dark CO2 fixation in arctic soils
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 incorpora...
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ftcdlib:oai:escholarship.org:ark:/13030/qt9hz3c08w 2023-09-05T13:17:20+02:00 Significance of dark CO2 fixation in arctic soils Šantrůčková, Hana Kotas, Petr Bárta, Jiří Urich, Tim Čapek, Petr Palmtag, Juri Alves, Ricardo J Eloy Biasi, Christina Diáková, Kateřina Gentsch, Norman Gittel, Antje Guggenberger, Georg Hugelius, Gustaf Lashchinsky, Nikolaj Martikainen, Pertti J Mikutta, Robert Schleper, Christa Schnecker, Jörg Schwab, Clarissa Shibistova, Olga Wild, Birgit Richter, Andreas 2018-04-01 application/pdf https://escholarship.org/uc/item/9hz3c08w unknown eScholarship, University of California qt9hz3c08w https://escholarship.org/uc/item/9hz3c08w public Life on Land Anaplerotic enzymes Carboxylase genes Microbial community composition Permafrost soils C-13 enrichment of soil profile Environmental Sciences Biological Sciences Agricultural and Veterinary Sciences Agronomy & Agriculture article 2018 ftcdlib 2023-08-21T18:05:46Z 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. Article in Journal/Newspaper Arctic permafrost Tundra University of California: eScholarship Arctic |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Life on Land Anaplerotic enzymes Carboxylase genes Microbial community composition Permafrost soils C-13 enrichment of soil profile Environmental Sciences Biological Sciences Agricultural and Veterinary Sciences Agronomy & Agriculture |
spellingShingle |
Life on Land Anaplerotic enzymes Carboxylase genes Microbial community composition Permafrost soils C-13 enrichment of soil profile Environmental Sciences Biological Sciences Agricultural and Veterinary Sciences Agronomy & Agriculture Šantrůčková, Hana Kotas, Petr Bárta, Jiří Urich, Tim Čapek, Petr Palmtag, Juri Alves, Ricardo J Eloy Biasi, Christina Diáková, Kateřina Gentsch, Norman Gittel, Antje Guggenberger, Georg Hugelius, Gustaf Lashchinsky, Nikolaj Martikainen, Pertti J Mikutta, Robert Schleper, Christa Schnecker, Jörg Schwab, Clarissa Shibistova, Olga Wild, Birgit Richter, Andreas Significance of dark CO2 fixation in arctic soils |
topic_facet |
Life on Land Anaplerotic enzymes Carboxylase genes Microbial community composition Permafrost soils C-13 enrichment of soil profile Environmental Sciences Biological Sciences Agricultural and Veterinary Sciences Agronomy & Agriculture |
description |
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. |
format |
Article in Journal/Newspaper |
author |
Šantrůčková, Hana Kotas, Petr Bárta, Jiří Urich, Tim Čapek, Petr Palmtag, Juri Alves, Ricardo J Eloy Biasi, Christina Diáková, Kateřina Gentsch, Norman Gittel, Antje Guggenberger, Georg Hugelius, Gustaf Lashchinsky, Nikolaj Martikainen, Pertti J Mikutta, Robert Schleper, Christa Schnecker, Jörg Schwab, Clarissa Shibistova, Olga Wild, Birgit Richter, Andreas |
author_facet |
Šantrůčková, Hana Kotas, Petr Bárta, Jiří Urich, Tim Čapek, Petr Palmtag, Juri Alves, Ricardo J Eloy Biasi, Christina Diáková, Kateřina Gentsch, Norman Gittel, Antje Guggenberger, Georg Hugelius, Gustaf Lashchinsky, Nikolaj Martikainen, Pertti J Mikutta, Robert Schleper, Christa Schnecker, Jörg Schwab, Clarissa Shibistova, Olga Wild, Birgit Richter, Andreas |
author_sort |
Šantrůčková, Hana |
title |
Significance of dark CO2 fixation in arctic soils |
title_short |
Significance of dark CO2 fixation in arctic soils |
title_full |
Significance of dark CO2 fixation in arctic soils |
title_fullStr |
Significance of dark CO2 fixation in arctic soils |
title_full_unstemmed |
Significance of dark CO2 fixation in arctic soils |
title_sort |
significance of dark co2 fixation in arctic soils |
publisher |
eScholarship, University of California |
publishDate |
2018 |
url |
https://escholarship.org/uc/item/9hz3c08w |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic permafrost Tundra |
genre_facet |
Arctic permafrost Tundra |
op_relation |
qt9hz3c08w https://escholarship.org/uc/item/9hz3c08w |
op_rights |
public |
_version_ |
1776198540682330112 |