UFZ-Seminar "Water and Environment"

Programme 2016

29 January 2016, 11am - Marc Piepoch (University of Montana, Institute on Ecosystems)

15 February 2016, 3pm - Eric von Elert (Universität zu Köln)

18 April 2016, 3pm - Peter Krebs (TU Dresden)

23 May 2016, 3pm - Gregor Ollesch (RBC Elbe)

15 August 2016, 3pm - Stan Harpole (Department of Physiological Diversity, UFZ)

24 October 2016, 3.30pm - Martyn Futter (Swedish University of Agricultural Sciences, University Uppsala)

21 November 2016, 3pm - Michael Mutz (BTU Cottbus-Senftenberg)

Michael Mutz (BTU Cottbus-Senftenberg)

Drying and moving sediments - overlooked but coming, sediment metabolism at hydrological extremes

Monday, November 21th 2016, 3pm
Brückstraße 3a, 39114 Magdeburg, Seminarroom

Drought and heavy rainfall are the extremes in the hydrological drivers of stream ecosystems. These extremes are predicted to be further pronounced in the temperate zone with change of climate and land use and consequently periodic and episodic ephemeral reaches will increase their extent. On the other hand the load of fine sediments from surface runoff will increase, in turn expanding the percentage of stream bed covered by patches of quasi constantly moving bed forms. In experimental studies in outdoor flumes and laboratory microcosms we investigated how these two extremes affect the microbial metabolism associated to the sediments. The drying reduced community respiration and the strength of this response was related to the humidity in the sediment pore space during drought. Shifting sands had surprising little effect on the quality of particulate organic matter transported within migrating sand ripples, while the community respiration and primary production were severely curbed in this highly dynamic habitat. The resilience of the metabolic function to both stressors was surprisingly fast. However, clear changes of the community structure were observed from pre to post stress. Our findings suggest that streams C-transformations are well buffered against, respectively resilient to even extreme hydrological stress, while the stress changes the structure of the obviously functionally redundant microbial community.