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SUMMARY:EESS talk on "Interactions of cyanobacterial blooms with energy fl
 uxes across the air-water interface in lakes"
DTSTART:20210601T121500
DTEND:20210601T130000
DTSTAMP:20260427T204105Z
UID:6929b83d02ddce05e19e02c91e14d25e1d5fc118a9cb936db3535619
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr Andreas Lorke\, Professor\, Environmental Physics Group\, K
 oblenz University-Landau\, DE\nAbstract:\nWind-induced water motions are a
 n important physical characteristic of lakes and play a vital role in thei
 r ecology and biogeochemistry. Yet little is known about the controls on m
 omentum transfer from wind to water and its interaction with biochemical c
 haracteristics of the water surface at low wind speed. Cyanobacterial bloo
 ms are harmful phenomena that negatively affect water quality\, human and 
 animal health. Colony-forming Microcystis is one of the most important and
  ubiquitous genera that can suddenly accumulate at water surfaces\, formin
 g surface scum. We studied the processes of scum formation and its respons
 e to wind-generated turbulence in a laboratory mesocosm. We observed a str
 ong reduction of momentum transfer from wind to water with a growing scum 
 layer. The presence of the scum increased the threshold wind speed for the
  onset of flow and reduced flow velocities that were generated by wind spe
 eds above that threshold. This effect was likely caused by the presence of
  a film of surface-active material at the water surface (surface microlaye
 r)\, which is related to the presence of Microcystis. We hypothesize that 
 the surface microlayer plays an important\, yet largely unexplored role bo
 th in Microcystis surface scum development and in energy fluxes across the
  air-water interface in aquatic ecosystems. In my talk\, I will highlight 
 recent results and discuss future research directions.\n\nShort biography:
 \nProfessor Lorke is a physicist with a research focus on environmental fl
 uid mechanics and physical limnology. In his lab\, which was founded in 20
 08 at the University of Koblenz-Landau\, the research focuses on how water
  flows in aquatic ecosystems are generated\, how they interact with organi
 sms\, transport material and affect biogeochemical cycling. The lab's inte
 rdisciplinary research projects range from analyses of individual swimming
  organisms to the quantification of global biogeochemical cycles. With the
  findings\, the lab contribute to the understanding of how water systems a
 re affected by global change and how water resources management can be imp
 roved to provide sustainability and to maintain biodiversity.
LOCATION:ZOOM https://epfl.zoom.us/j/84677261593
STATUS:CONFIRMED
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