PhD defense: Sarah Hagel Svendsen – Biologisk Institut - Københavns Universitet

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PhD defense: Sarah Hagel Svendsen

Arctic emissions of biogenic volatile organic compounds – from plants, litter and soils

Supervisors
Professor Riikka Rinnan (principal), BIO-UCPH
Professor Anders Michelsen, BIO-UCPH

Evaluation committee
Associate professor Guy Schurgers, University of Copenhagen, Denmark (Chair)
Senior Researcher Aino Smolander, Natural Resources Institute Finland (Luke), Finland
Research Scientist Elena Ormeño Lafuente, Aix-Marseille University, France

Abstract
Significant amounts of biogenic volatile organic compounds are emitted from terrestrial ecosystems. These emissions may influence the atmospheric chemistry and the climate. Climate warming will be most pronounced in the Arctic and this will likely have a large effect on the BVOC emissions. Despite this, BVOC emissions from arctic ecosystems are sparsely studied. For this PhD project, I have studied arctic BVOC emissions from a soil moisture gradient, from decomposing shrub litter at increasing temperature and from active layer soils and permafrost soils during a thaw event and at increasing temperature.

I show that ecosystem BVOC emissions differ in both the composition and rates along a soil moisture gradient with changes in plant species composition. Furthermore, I show that litter emissions may derive both from microbial processes and from stores inside the litter tissue and that the relative importance of these two sources might be plant species specific. I also find that BVOC emissions from active layer soils and permafrost soils depend greatly on the soil water content and temperature.

A warmer arctic climate will likely alter the composition of arctic plant species, cause a thawing of permafrost soil and change soil characteristics such as the water content. This PhD project suggests that these changes will alter the composition of arctic BVOCs emissions and increase the magnitude.