Brindza, N. R. Utah State University, nbrindza@cc.usu.edu
Luecke, C. R. Utah State University, luecke@cc.usu.edu
Wurtsbaugh, W. Utah State University, wurts@cc.usu.edu

 
THE EFFECTS OF DIEL MIGRATION CHANGES ON ZOOPLANKTON GRAZING RATES
 
The zooplankton community of a small oligotrophic lake in central Idaho was examined from early June through September. In situ grazing rates for the community were determined several times during the year. Individual species grazing rates were also determined under laboratory conditions. Vertical migration of zooplankton was minimal in early summer with the majority of zooplankton biomass residing in epilimnetic water during day and night. Diel vertical migration increased during the summer such that by late August zooplankton biomass was greatest in the hypolimnion by day. This increase in migration resulted in significant changes in grazing rates. Hypolimnetic phytoplankton suffered greater losses to grazing as a result of increased numbers of zooplankton, especially Daphnia, during daylight hours. Epilimnetic grazing decreased dramatically during daytime and increased during nighttime hours.
 
Day: Wednesday, Feb. 3
Time: Poster
Location: Sweeney Center
 
Code: SS21WE0874S