Temperature sensitivity of microbial processes and functions in a long-term soil warming experiment

Jörg Schnecker1, Wolfgang Wanek1, Mounir Takriti1, Andreas Schindlbacher2
1 Department of Microbiology and Ecosystem Science, University of Vienna
2 Federal Research and Training Centre for Forests, Natural Hazards and Landscape

O 2.7 in Environmental controls on fluxes and processes in ecosystems

17.07.2014, 11:20-11:40, H18

Temperature is a main driver of microbial processes in soils, with (bio)chemical processes increasing with temperature. A long-term increase in soil temperature however can change the functional properties of microbial decomposer communities and thereby alter microbial processes. These alterations might in turn lead to enhanced decomposition and a loss of CO2 from soils to the atmosphere. In a long-term soil warming experiment in a mature spruce forest, after 9 years of warming, soil respiration was still significantly higher in warmed than in control plots. To elucidate whether or not a functional adaptation of the soil microbial community to warming has occurred we determined the temperature sensitivity (Q10) of soil respiration, extracellular enzyme activities, microbial substrate use efficiency (SUE) and gross nitrogen mineralization. Results at this early stage of data evaluation show no differences in Q10 values of respiration, enzyme activities and SUE between warmed and control plots. Our results suggest that the 4°C increase in soil temperature in warmed plots did not alter the temperature sensitivity of microbial processes and functions. The absence of thermal adaptation of soil microbes in this field experiment might therefore contribute greatly to the observed increase in total soil respiration in warmed plots. 

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Letzte Änderung 03.04.2014