Impact of climate warming on soil exoenzyme kinetic properties and their role in forecasting carbon flux

ended

The majority of the Earth’s terrestrial carbon (C) is stored in the soil as organic carbon, at quantities more than three times the size of the atmospheric carbon pool. Response of this vast reservoir of C to climate change is highly uncertain and changes may alter multiple soil ecosystem services such as climate regulation, food production and water purification. Soil microorganisms drive the decomposition of soil organic C and determine C losses from soils to the atmosphere through soil respiration (Rsoil). To date, no consensus has been reached on the direction or magnitude of Rsoil responses to climate change with contrasting results and conflicting theory making future predictions unreliable. Up to now, research into rising temperature respiratory responses has focussed on substrate depletion mechanisms and metabolic adjustments, with little attention being paid to the importance of change in exoenzyme kinetic properties. Bringing together state of the art measurements from different rarely combined disciplines, this EUsoil-C-FLUX project will focus on soil exoenzyme thermal adaptation to unravel new mechanisms of Rsoil response to climate warming at the European scale. To this end, this project proposes to (i) determine the local adaptation of soil exoenzyme kinetic properties across Europe, from Greece to Iceland in three major habitats (grassland, forest and peatland); (ii) impose a controlled warming experient on these soils in a unique world leading research facility (the European Ecotron of Montpellier); (iii) use cutting edge and interdisciplineray technology (isotope labelling, high throughput DNA sequencing, radio carbon dating) to provide a detailed mechanistic understanding of Rsoil responses to warming; and finally (iv) incorporate the new findings into the latest mechanistic C models to better predict Rsoil response to climate change, a prerequisite to fulfill a key priority of the European Union in reducing greenhouse gas emissions.