Sulzberger, B. ., Eawag: Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Duebendorf, Switzerland, sulzberger@eawag.ch
Durisch-Kaiser, E. ., Institute of Biogeochemistry and Pollution Dynamics, ETH Zurich, CH-8092 Zurich, Switzerland, edith.durisch-kaiser@env.ethz.ch

WHY DO WE NEED TO SPAN THE RANGE FROM MOLECULAR-LEVEL TO WHOLE ECOSYSTEM SCALE STUDIES IN AQUATIC PHOTOCHEMICAL RESEARCH?

This question will be addressed regarding the light-induced cycling of natural dissolved organic matter (DOM) in aquatic systems. The optical properties, bioavailability, and rates of microbial and abiotic mineralization of DOM depend on the origin and chemical composition of DOM and are strongly affected by solar radiation. For example, terrestrially derived DOM often exhibits a higher photoreactivity than autochthonous DOM, and light-induced transformations of terrigenous DOM tend to increase DOM bioavailability. Because of the strong link between the chemical composition and the photochemical and biological reactivity of DOM, the molecular-level characterization of DOM is a prerequisite for a better understanding of the effects of solar radiation, particularly UVR, on carbon cycling. Furthermore, mathematical kinetic modeling in conjunction with experimental studies greatly helps to assess individual (photo)chemical reactions occurring in complex heterogeneous aqueous systems. This paper will present study results from my research group at Eawag that combined photochemical laboratory experiments, kinetic modeling, and molecular-level characterization involving natural and synthetic DOM systems. It will be discussed how these studies help understand the fate of DOM in sunlit aquatic ecosystems.

Oral presentation

Presentation is given by student: No
Session #:SS01
Date: Friday, June 13, 2008
Time: 10:00 AM

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