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Walker TWN, Kaiser C, Strasser F, Herbold CW, Leblans NIW, Woebken D, Janssens IA, Sigurdsson BD, Richter A. Microbial temperature sensitivity and biomass change explain soil carbon loss with warming. NATURE CLIMATE CHANGE 2018. [PMID: 30288176 DOI: 10.1038/s41558-018-0322-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Soil microorganisms control carbon losses from soils to the atmosphere1-3, yet their responses to climate warming are often short-lived and unpredictable4-7. Two mechanisms, microbial acclimation and substrate depletion, have been proposed to explain temporary warming effects on soil microbial activity8-10. However, empirical support for either mechanism is unconvincing. Here we used geothermal temperature gradients (> 50 years of field warming)11 and a short-term experiment to show that microbial activity (gross rates of growth, turnover, respiration and carbon uptake) is intrinsically temperature sensitive and does not acclimate to warming (+ 6 ºC) over weeks or decades. Permanently accelerated microbial activity caused carbon loss from soil. However, soil carbon loss was temporary because substrate depletion reduced microbial biomass and constrained the influence of microbes over the ecosystem. A microbial biogeochemical model12-14 showed that these observations are reproducible through a modest, but permanent, acceleration in microbial physiology. These findings reveal a mechanism by which intrinsic microbial temperature sensitivity and substrate depletion together dictate warming effects on soil carbon loss via their control over microbial biomass. We thus provide a framework for interpreting the links between temperature, microbial activity and soil carbon loss on timescales relevant to Earth's climate system.
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Affiliation(s)
- Tom W N Walker
- Department of Microbiology & Ecosystem Science, Division of Terrestrial Ecosystem Research, University of Vienna, 1090 Vienna, Austria
- Department of Ecology & Evolution, Université de Lausanne, CH-1015, Switzerland
| | - Christina Kaiser
- Department of Microbiology & Ecosystem Science, Division of Terrestrial Ecosystem Research, University of Vienna, 1090 Vienna, Austria
- Institute of Applied Systems Analysis, 2361 Laxenburg, Austria
| | - Florian Strasser
- Department of Microbiology & Ecosystem Science, Division of Microbial Ecology, University of Vienna, 1090 Vienna, Austria
| | - Craig W Herbold
- Department of Microbiology & Ecosystem Science, Division of Microbial Ecology, University of Vienna, 1090 Vienna, Austria
| | - Niki I W Leblans
- Department of Biology, University of Antwerp, 2610 Wilrijk, Antwerp, Belgium
- Agricultural University of Iceland, Hvanneyri, 311 Borgarnes, Iceland
| | - Dagmar Woebken
- Department of Microbiology & Ecosystem Science, Division of Microbial Ecology, University of Vienna, 1090 Vienna, Austria
| | - Ivan A Janssens
- Department of Biology, University of Antwerp, 2610 Wilrijk, Antwerp, Belgium
| | | | - Andreas Richter
- Department of Microbiology & Ecosystem Science, Division of Terrestrial Ecosystem Research, University of Vienna, 1090 Vienna, Austria
- Institute of Applied Systems Analysis, 2361 Laxenburg, Austria
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Walker TWN, Kaiser C, Strasser F, Herbold CW, Leblans NIW, Woebken D, Janssens IA, Sigurdsson BD, Richter A. Microbial temperature sensitivity and biomass change explain soil carbon loss with warming. NATURE CLIMATE CHANGE 2018; 8:885-889. [PMID: 30288176 PMCID: PMC6166784 DOI: 10.1038/s41558-018-0259-x] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 07/19/2018] [Indexed: 05/25/2023]
Abstract
Soil microorganisms control carbon losses from soils to the atmosphere1-3, yet their responses to climate warming are often short-lived and unpredictable4-7. Two mechanisms, microbial acclimation and substrate depletion, have been proposed to explain temporary warming effects on soil microbial activity8-10. However, empirical support for either mechanism is unconvincing. Here we used geothermal temperature gradients (> 50 years of field warming)11 and a short-term experiment to show that microbial activity (gross rates of growth, turnover, respiration and carbon uptake) is intrinsically temperature sensitive and does not acclimate to warming (+ 6 ºC) over weeks or decades. Permanently accelerated microbial activity caused carbon loss from soil. However, soil carbon loss was temporary because substrate depletion reduced microbial biomass and constrained the influence of microbes over the ecosystem. A microbial biogeochemical model12-14 showed that these observations are reproducible through a modest, but permanent, acceleration in microbial physiology. These findings reveal a mechanism by which intrinsic microbial temperature sensitivity and substrate depletion together dictate warming effects on soil carbon loss via their control over microbial biomass. We thus provide a framework for interpreting the links between temperature, microbial activity and soil carbon loss on timescales relevant to Earth's climate system.
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Affiliation(s)
- Tom W. N. Walker
- Department of Microbiology & Ecosystem Science, Division of Terrestrial Ecosystem Research, University of Vienna, 1090 Vienna, Austria
- Department of Ecology & Evolution, Université de Lausanne, CH-1015, Switzerland
| | - Christina Kaiser
- Department of Microbiology & Ecosystem Science, Division of Terrestrial Ecosystem Research, University of Vienna, 1090 Vienna, Austria
- Institute of Applied Systems Analysis, 2361 Laxenburg, Austria
| | - Florian Strasser
- Department of Microbiology & Ecosystem Science, Division of Microbial Ecology, University of Vienna, 1090 Vienna, Austria
| | - Craig W. Herbold
- Department of Microbiology & Ecosystem Science, Division of Microbial Ecology, University of Vienna, 1090 Vienna, Austria
| | - Niki I. W. Leblans
- Department of Biology, University of Antwerp, 2610 Wilrijk, Antwerp, Belgium
- Agricultural University of Iceland, Hvanneyri, 311 Borgarnes, Iceland
| | - Dagmar Woebken
- Department of Microbiology & Ecosystem Science, Division of Microbial Ecology, University of Vienna, 1090 Vienna, Austria
| | - Ivan A. Janssens
- Department of Biology, University of Antwerp, 2610 Wilrijk, Antwerp, Belgium
| | | | - Andreas Richter
- Department of Microbiology & Ecosystem Science, Division of Terrestrial Ecosystem Research, University of Vienna, 1090 Vienna, Austria
- Institute of Applied Systems Analysis, 2361 Laxenburg, Austria
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