Temperature Increases Soil Respiration Across Ecosystem Types and Soil Development, But Soil Properties Determine the Magnitude of This Effect

Soil carbon losses to the atmosphere, via soil heterotrophic respiration, are expected to increase in response to global warming, resulting in a positive carbon-climate feedback. Despite the well-known suite of abiotic and biotic factors controlling soil respiration, much less is known about how the magnitude of soil respiration responses to temperature changes over soil development and across contrasting soil properties. Here we investigated the role of soil development stage and soil properties in driving the responses of soil heterotrophic respiration to temperature. We incubated soils from eight chronosequences ranging in soil age from hundreds to million years, and encompassing a wide range of vegetation types, climatic conditions and chronosequences origins, at three assay temperatures (5 °C, 15 °C and 25 °C). We found a consistent positive effect of assay temperature on soil respiration rates across the eight chronosequences evaluated. However, chronosequences parent materials (sedimentary/sand dunes or volcanic) and soil properties (pH, phosphorus content and microbial biomass) determined the magnitude of this temperature effect. Finally, we observed a positive effect of soil development stage on soil respiration across chronosequences that did not alter the magnitude of assay temperature effects. Our work reveals that key soil properties alter the magnitude of the positive effect of temperature on soil respiration found across ecosystem types and soil development stages. This information is essential to better understand the magnitude of the carbon-climate feedback and thus to establish accurate greenhouse gas emission targets.

This research received funding from the European Union’s Horizon 2020 research and innovation program under Marie Sklodowska-Curie Grant Agreement 702057. M.D. was supported by an FPU fellowship from the Spanish Ministry of Education, Culture and Sports (FPU-15/00392). M.D. and F.T.M. are supported by the European Research Council (Consolidator Grant Agreement No 647038, BIODESERT). M.D-B. is supported by a Large Research Grant from the British Ecological Society (grant agreement n° LRA17\1193, MUSGONET). F.T.M and M.D-B. acknowledge support from the Spanish Ministry (project CGL2017-88124-R). PGP and M.D-B. are supported by a Ramón y Cajal grant from the Spanish Ministry of Science and Innovation (RYC2018-024766-I and RYC2018-025483-I, respectively). F.T.M. acknowledges support from the Generalitat Valenciana (CIDEGENT/2018/041).