München 2019 – scientific programme
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UP: Fachverband Umweltphysik
UP 9: Hydrology, oceanography and miscellaneous
UP 9.1: Invited Talk
Thursday, March 21, 2019, 14:00–14:30, HS 22
Hydrodynamic control of biogeochemical cycling in streams — •Andreas Lorke1, Christian Noss1, Christine Anlanger1, Ute Risse-Buhl2, and Markus Weitere2 — 1Institute for Enviromental Sciences, University of Koblenz-Landau, Forststr. 7, 76829 Landau — 2Department River Ecology, Helmholtz Centre for Environmental Research UFZ, Brückstraße 3a, 39114 Magdeburg
Low-order streams form the most abundant and the largest component of fluvial networks. They transport and process particulate and dissolved substances of terrestrial or anthropogenic origin. For example, they can be strong sources of the atmospheric greenhouse gases CO2, CH4 and N2O, and they convert anthropogenic nitrate loads into N2. Biodiversity and biogeochemical cycling in streams, as well their spatial and temporal variability are ubiquitously linked to flow velocity and turbulence. Although stream flow has been modified globally by human activities, the processes by which flow and turbulence regulate biogeochemical cycling and biodiversity are poorly understood. Here we analyze the interactions between streambed and water surface roughness and their influence on stream flow turbulence and atmospheric aeration rates. By combining existing ecological and physical frameworks, we present a novel concept for quantifying physical heterogeneity in streams. The concept is applied to study the effects of physical heterogeneity on biodiversity and ecological functioning of epilithic biofilms.