CAN FLOOD - The role of benthic processes for carbon and nitrogen cycling in complex floodplain landscapes
Abstract
River ecosystems play a key role in the transport and transformation of carbon and nutrients. While material is being transported downstream, organic matter is produced and degraded. This matter carries the fingerprint of human activities along its entire course. Microbial community features such as composition and activity are the major biotic component in all processes, especially in nitrogen cycling. Within the riverine landscape these processes are strongly associated with the availability of retention zones such as floodplain, riparian and instream zones. The processes related to nutrient and organic matter cycling are basically controlled by the hydromorphology. Thus, at the landscape scale, three fundamental principles regulate the cycling and transfer of carbon and nitrogen in river ecosystems: i) The mode of carbon and nitrogen delivery affects ecosystem functioning; ii) Increasing contact between water and soil or sediment increases nutrient retention and processing; iii) Floods and droughts are natural events that strongly influence pathways of carbon and nutrient cycling. These three principles can be strongly affected either by natural disturbances or anthropogenic impacts, which involve altered water regimes or a change in the geomorphologic setting of the river valley. An altered natural water regime will affect the biogeochemistry of riparian and instream zones as well as their ability to cycle and mitigate nutrient fluxes originating from upstream and upslope. This calls for a more integrated approach including restoration of landscape dynamics and key ecosystem processes such as carbon and nutrient retention. In this context the objectives of our project are i) to understand the consequences of changes in flow regimes on the functioning of river ecosystems and, more specifically, on their nitrogen cycling capacity, and ii) to accurately estimate the rates of these biogeochemical processes under hydrological changes. The following 3 hypotheses based on the 3 above-mentioned fundamental principles are the methodological approach to investigate the regulation of nitrogen and carbon cycling and transfer at the sediment/water interface in retention areas of river ecosystems: H1: The hydrogeomorphic structures of floodplains affect the quality of carbon input and the nitrogen dynamics in retention areas H2: The quality and quantity of organic carbon supply in alluvial zones affect nitrogen cycling in the sediments of retention areas H3: The resistance and the resilience of nutrient cycling processes to restoration and rehabilitation measures is controlled by past water regime patterns
Nutrient dynamics in riverine floodplains Floodplain restauration
Publikationen
Project staff
Thomas Hein
Univ.Prof. Dr. Thomas Hein
thomas.hein@boku.ac.at
Tel: +43 1 47654-81201, 81229
Project Leader
01.07.2007 - 31.03.2011
Helmut Habersack
Univ.Prof. Dipl.-Ing. Dr.nat.techn. Dr.h.c. Helmut Habersack
helmut.habersack@boku.ac.at
Tel: +43 1 47654-81901, 81911
Sub Projectleader
01.07.2007 - 31.03.2011
Elisabeth Bondar-Kunze
Mag. Dr. Elisabeth Bondar-Kunze
elisabeth.bondar@boku.ac.at
Tel: +43 1 47654-81206
Project Staff
01.07.2007 - 31.03.2011
BOKU partners
External partners
Wassercluster Lunz - biologische Station GmbH
Thomas Hein
partner