SS3.04 Biogeochemistry of DOC/DON in a Watershed Context
Date: Wednesday, June 12, 2002
Time: 9:45:00 AM
Location: Carson B
 
PeduzziP, University of Vienna, IECB, Vienna, Austria, peter.peduzzi@univie.ac.at
Hein, T, , University of Vienna, IECB, Vienna, Austria, thomas.hein@univie.ac.at
Schelest, J, , University of Vienna, IECB, Vienna, Austria, 
 
IMPACT OF HYDROLOGY ON THE BIOGEOCHEMISTRY OF DOM IN A DYNAMIC RIVER–FLOODPLAIN SYSTEM
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Most large rivers in the temperate zone are greatly impacted by regulation work and active floodplains have been drained or disconnected. Since these changes have led to alterations of the biological compartments, it can be assumed that dissolved organic matter (DOM), as one important component, is also affected. In Austria, the ”Danube Restoration Project” was implemented within a National Park zone to re-establish the connectivity between the Danube and selected floodplain segments. DOM properties and reactivity were investigated in the years 1999/2000/2001 under varying hydrologic conditions. Most DOM parameters, like molecular size distribution, C:N-ratios, stable isotope signatures, carbohydrate contents or optical properties were significantly related to the hydrologic regime of the floodplain pools. Bacterial secondary production appeared to respond to these changes. As a consequence, the re-connection of backwaters is thought to influence both the C-cycling within the floodplains and also the downstream-integrated biochemistry of the main river. Therefore, the investigation of DOM properties should become an integrated part of the ecological evaluation of restoration programs.