Biologically- induced Mixing of Stratified Waters by Swimming Zooplankton

• Applicant: Professor Dr. Andreas Lorke
• Subject Area: Hydrogeology, Hydrology, Limnology, Urban Water Management, Water Chemistry, Integrated Water Resources Management
• Term: from 2011 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 193232038

Swimming of aquatic organisms is associated with the generation of velocity fluctuations and fluid mixing. Such biologically-generated flows are not only important for the organisms itself, by affecting nutrient uptake, predator-prey interactions, and the perception of hydrodynamic and chemical signals, an ongoing scientific debate also concerns their importance for the vertical mass and heat transport on basin-scales. In this project we will quantify the fluid transport associated with swimming zooplankton in density-stratified waters. Although zooplankton belongs to the smallest motile organisms in aquatic ecosystems, their contribution to biomixing are expected to be important because they occur in high densities and many zooplankton species perform a diel vertical migration. Using volumetric particle image velocimetry for characterizing the flow field, in combination with laser-induced fluorescence for measuring scalar transport and fluxes, we will quantify the biologically-induced mixing due to individuals, groups of interacting organisms, and vertically migrating zooplankton, in a series of laboratory experiments.

• DFG Programme: Research Grants
• Major Instrumentation: PLIF-System (zusätzl. Laser + zusätzl. CCD-Kamera)
• Instrumentation Group: 8860 Geschwindigkeitsmeßgeräte (außer 047, 053, 192 und 244)
• Participating Person: Dr.-Ing. Christian Noß