Non-phototrophic CO2 fixation by soil microorganisms

By Anja Miltner, F. Kopinke, R. Kindler, D. Selesi, Anton Hartmann, Matthias Kästner. Plant and Soil, 2005

113 citations recorded by the source corpus.

Although soils are generally known to be a net source of CO2 due to microbial respiration, CO2 fixation may also be an important process. The non-phototrophic fixation of CO2 was investigated in a tracer experiment with 14CO2 in order to obtain information about the extent and the mechanisms of this process. Soils were incubated for up to 91 days in the dark. In three independent incubation experiments, a significant transfer of radioactivity from 14CO2 to soil organic matter was observed. The process was related to microbial activity and could be enhanced by the addition of readily available substrates such as acetate. CO2 fixation exhibited biphasic kinetics and was linearly related to respiration during the first phase of incubation (about 20–40 days). The fixation amounted to 3–5% of the net respiration. After this phase, the CO2 fixation decreased to 1–2% of the respiration. The amount of carbon fixed by an agricultural soil corresponded to 0.05% of the organic carbon present in the soil at the beginning of the experiment, and virtually all of the fixed CO2 was converted to organic compounds. Many autotrophic and heterotrophic biochemical processes result in the fixation of CO2. However, the enhancement of the fixation by addition of readily available substrates and the linear correlation with respiration suggested that the process is mainly driven by aerobic heterotrophic microorganisms. We conclude that heterotrophic CO2 fixation represents a significant factor of microbial activity in soils.

Subfields: Ecology, Global and Planetary Change, Soil Science

View Paper: https://www.semanticscholar.org/paper/ec8c849012e3a0bc20abc4eb4db8ca730155b408

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In Ecology

1. Christoph Emmerling
2. R. Joergensen
3. Y. Kuzyakov
4. E. Blagodatskaya
5. P. Chamberlain
6. Liliane Ruess

In Global and Planetary Change

1. J. Jansa

In Soil Science

1. Christoph Emmerling
2. R. Joergensen
3. J. Jansa
4. Y. Kuzyakov
5. Liliane Ruess
6. E. Blagodatskaya
7. P. Chamberlain

Citations in the corpus

• Methods for evaluating human impact on soil microorganisms based on their activity, biomass, and diversity in agricultural soils (2006, background): “In addition, CO2-production rates may also be affected by autotrophic microorganisms in soil, which fix atmospheric CO2 (Miltner et al., 2005; Stein et al., 2005).”
• Carbon flow from plant to arbuscular mycorrhizal fungi is reduced under phosphorus fertilization (2017, background): “This notion is supported by the fact that non-phototrophic CO2 fixation by heterotrophic soil organisms is about one to two orders of magnitude lower than are their respiration rates (Miltner et al. 2005).”
• Soil-carbon preservation through habitat constraints and biological limitations on decomposer activity (2008, unknown): “…et al., 2005). c) CO 2 was strongly re-assimilated under experimental stimulation through H 2 , as compared to the control treatment (Stein et al., 2005). d) Under ambient conditions, a proportion of 2%–5% respired CO 2 was re-assimilated in a tracer experiment with 14 CO 2 (Miltner et al., 2005a).”