Convener: Reinhard Well  | Co-Conveners: Dries Roobroeck , Yit Arn Teh , Reinhard Well , Klaus Butterbach-Bahl 
Wed, 05 May, 14:00–14:45  / Room 35

The contribution of microbial denitrification to nitrogen cycling in terrestrial and aquatic ecosystems is poorly understood. Exchanges of gaseous N species by microbial denitrification are of importance to ecosystem N budgets as well as to global warming scenarios and stratospheric ozone degradation. Quantification of gaseous N exchange rates is a great analytical challenge, precise and accurate detection of gaseous N fluxes is difficult because of high ambient backgrounds and quantitatively small mass fluxes. Since dynamics of microbial denitrification have mostly been investigated under laboratory conditions, the effective control at the field scale and the spatial variability of in situ denitrification is still not sufficiently clarified. Due to the lack of suitable data-sets, process-based denitrification models have rarely been validated and results of their application on site-specific and regional scales are highly uncertain. Recent technological advances in measurements of N2 fluxes and linking structure and activity of denitrifying microbial communities with denitrification rates offer new opportunities in this area. We invite contributions from the following fields:
Methodical advances in measuring and modelling of denitrification in soils, wetlands, aquifers and open water bodies; measuring N2 and N2O fluxes from denitrification and controlling factors under field-like conditions using methods like incubation under He atmosphere, 15N-Tracer technique, natural abundance stable isotopes signatures of N2O and N2 fluxes, or N2/Ar ratios; method comparisons; process-based modelling of denitrification at various scales; linking denitrification rates to parameters of the denitrifying community.

Public information: This session will provide short oral presentations of the posters (for list and abstracts see poster session BG 2.13), followed by a plenary discussion.