PhD defense Magnus Kramshøj

Biogenic volatile organic compounds in a changing climate - Emissions from an Arctic heath and permafrost soil, and uptake by microbes

Supervisors:Riikka Rinnan, BIO-UCPH and Christian Albers, GEUS

Evaluation Committee:
Anders Michelsen, BIO-UCPH (chair)
Christina Biasi, University of Eastern Finland
Janne Rinne, University of Lund

Abstract
The PhD project deals with the emissions of biogenic volatile organic compounds (BVOCs) from Arctic ecosystems and how this will be affected by future climate changes. All living organisms release BVOCs, which are reactive gases that have impacts on the atmospheric concentrations of methane, ozone, secondary organic aerosol and clouds. The Arctic is particularly sensitive to climate changes and is currently experiencing climate warming at twice the rate compared to the global mean, while permafrost soils containing huge amounts of carbon are thawing. I find that a 2 °C rise in temperature increase Arctic tundra BVOC emissions by 260%, while an increased simulated cloud cover decerase emissions by 70%. Furthermore thawing permafrost soils are found to release significant amounts of BVOCs. Most of these compounds are however mineralized by a range of soil types in varying rate, and will therefore never reach the atmosphere.