Speekmann, C. L.. Romberg Tiburon Center for Environmental Studies and Department of Biology, San Francisco State University, speekman@sfsu.edu
Bollens, S. L.. Romberg Tiburon Center for Environmental Studies and Department of Biology, San Francisco State University, sbollens@sfsu.edu
Avent, S. R.. Romberg Tiburon Center for Environmental Studies and Department of Biology, San Francisco State University, savent@sfsu.edu

 
THE EFFECTS OF ULTRAVIOLET RADIATION ON MORTALITY AND VERTICAL MIGRATION OF ZOOPLANKTON FROM SAN FRANCISCO BAY.
 
The importance of UV-B radiation (280 - 320 nm) in altering the survival and behavior of marine zooplankton has been the subject of conflicting reports in the literature. The purpose of this study was to determine the effect of UV radiation on 1) the mortality and 2) the vertical migration of four calanoid copepods species: Acartia (Acartiura) sp. , A. californiensis, A. tonsa and Tortanus dextrilobutus, commonly found in San Francisco Bay. In the mortality experiments copepods were exposed to ambient levels of radiation and reduced levels of radiation (filtered with Mylar). A significantly higher mortality occurred for animals exposed to full radiation. Vertical migration experiments were conducted using 2 m high columnar mini-tower systems with infra-red video microscopy to determine the vertical distribution of organisms in the presence and absence of UV-B radiation. Our results show that copepods avoided the top 50 cm of the tank when UV-B radiation was present. These results, combined with those from the mortality experiments, suggest that copepods are able to reduce their exposure to harmful UV-B radiation by avoiding the very surface layer of the water column.
 
Day: Thursday, Feb. 4
Time: 02:00 - 02:15pm
Location: Hilton of Santa Fe
 
Code: SS16TH0200H