Details
| Original language | English |
|---|---|
| Pages (from-to) | 11-21 |
| Number of pages | 11 |
| Journal | Soil Biology and Biochemistry |
| Volume | 119 |
| Early online date | 11 Jan 2018 |
| Publication status | Published - Apr 2018 |
Abstract
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.
Keywords
- C enrichment of soil profile, Anaplerotic enzymes, Carboxylase genes, Microbial community composition, Permafrost soils
ASJC Scopus subject areas
- Immunology and Microbiology(all)
- Microbiology
- Agricultural and Biological Sciences(all)
- Soil Science
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In: Soil Biology and Biochemistry, Vol. 119, 04.2018, p. 11-21.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Significance of dark CO2 fixation in arctic soils
AU - Šantrůčková, Hana
AU - Kotas, Petr
AU - Bárta, Jiří
AU - Urich, Tim
AU - Čapek, Petr
AU - Palmtag, Juri
AU - Eloy Alves, Ricardo J.
AU - Biasi, Christina
AU - Diáková, Kateřina
AU - Gentsch, Norman
AU - Gittel, Antje
AU - Guggenberger, Georg
AU - Hugelius, Gustaf
AU - Lashchinsky, Nikolaj
AU - Martikainen, Pertti J.
AU - Mikutta, Robert
AU - Schleper, Christa
AU - Schnecker, Jörg
AU - Schwab, Clarissa
AU - Shibistova, Olga
AU - Wild, Birgit
AU - Richter, Andreas
N1 - Funding information: This study was supported by the International Program CryoCARB ( MSM 7E10073 – CryoCARB , FWF I370-B17 ), BMBF 03F0616A , MEYS ( LM 2015075 , cz.02.1.01/0.0/0.0/16_013/0001782 ) and Grant Agency ( 16-18453S ). TU and CS acknowledge support from NFR ? grant 200411 . CB acknowledges financial support from the Nessling foundation and the Academy of Finland (project COUP, decision no. 291691 ; part of the European Union Joint Programming Initiative, JPI Climate) and OS and GG appreciate support from the Russian Ministry of Education and Science (No. 14.B25.31.0031 ). The authors thank Gerhard Kerstiens for language editing and unknown reviewer for valuable comments. This study was supported by the International Program CryoCARB (MSM 7E10073 – CryoCARB, FWF I370-B17), BMBF 03F0616A, MEYS (LM 2015075, cz.02.1.01/0.0/0.0/16_013/0001782) and Grant Agency (16-18453S). TU and CS acknowledge support from NFR ? grant 200411. CB acknowledges financial support from the Nessling foundation and the Academy of Finland (project COUP, decision no. 291691; part of the European Union Joint Programming Initiative, JPI Climate) and OS and GG appreciate support from the Russian Ministry of Education and Science (No. 14.B25.31.0031). The authors thank Gerhard Kerstiens for language editing and unknown reviewer for valuable comments.
PY - 2018/4
Y1 - 2018/4
N2 - 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.
AB - 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.
KW - C enrichment of soil profile
KW - Anaplerotic enzymes
KW - Carboxylase genes
KW - Microbial community composition
KW - Permafrost soils
UR - http://www.scopus.com/inward/record.url?scp=85040237897&partnerID=8YFLogxK
U2 - 10.1016/j.soilbio.2017.12.021
DO - 10.1016/j.soilbio.2017.12.021
M3 - Article
AN - SCOPUS:85040237897
VL - 119
SP - 11
EP - 21
JO - Soil Biology and Biochemistry
JF - Soil Biology and Biochemistry
SN - 0038-0717
ER -