Land use intensity has a stronger effect on the temperature sensitivity of soil microbial carbon cycling processes than long-term climate change.
- 1University of Paris-Saclay, INRAE, AgroParisTech, UMR EcoSys, 91120 Palaiseau, France
- 2Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, 8057, Switzerland
- 3IFP Énergies Nouvelles, Rueil-Malmaison, France
- 4Institute of Earth Surface Dynamics, Faculty of Geosciences and the Environment, University of Lausanne, Lausanne, 1015, Switzerland
- 5Department of Environmental Sciences – Botany, University of Basel, Basel 4056, Switzerland
- 6Research Centre for Ecological Change, Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki 00014, Finland
- 7Department of Agroecology, Center for Landscape Research in Sustainable Agricultural Futures - Land-CRAFT, Aarhus University, Denmark
- 8Karlsruhe Institute of Technology, Institute for Meteorology and Climate Research, Atmospheric Environmental Research (IMK-IFU), Kreuzeckbahnstrasse 19, 82467 Garmisch-Partenkirchen, Germany
Microbes are responsible for the cycling of carbon (C) in soils, and predicted changes in soil C stocks under climate change are highly sensitive to shifts in the mechanisms thought to control microbial physiological response to warming. Two mechanisms have been proposed to explain the long-term effects of warming on microbial physiology: microbial thermal acclimation and changes in the quantity and quality of substrates available for microbial metabolism. However, studies disentangling these two mechanisms and assessing how land use affects them are lacking. To disentangle the drivers of changes in microbial physiology in response to long-term climate change, we sampled soils from a 10-year old global change and land use intensity experiment at the Pre-Alpine Terrestrial Environmental Observatories (TERENO project). The global change treatment includes a warming of 2oC and a reduction in precipitation of about 450 mm. We took soil samples at different time-points during the spring season and depths. We performed short-term laboratory incubations over a range of temperatures to measure the relationships between temperature sensitivity of physiology (growth, respiration, carbon use efficiency with the 18O-H2O method) and we characterized the quantity and quality of soil organic matter with the ramped thermal rock-eval pyrolysis at different depths. In this ongoing project, we did not observe thermal acclimation of microbial respiration, growth or CUE to climate change. However, fertilization had the strongest effect on the temperature sensitivity of microbial respiration. In the next steps of this project, we will determine whether climate change and/or land use intensity has an effect on soil organic carbon fractions with different residence times. Our preliminary results show that land use intensity has an overriding effect on the temperature sensitivity of microbial processes compared to long-term climate change.
How to cite: Domeignoz-Horta, L., McLaughlin, M., Soares Fontes, M., Sebag, D., Aubertin, M.-L., Verrecchia, E., Kahmen, A., Nelson, D., Laine, A.-L., Niklaus, P., Butterbach-Bahl, K., and Kiese, R.: Land use intensity has a stronger effect on the temperature sensitivity of soil microbial carbon cycling processes than long-term climate change., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16307, https://doi.org/10.5194/egusphere-egu24-16307, 2024.
