Aquatic Sciences Meeting, Albuquerque 2001

CS37 Zooplankton

Date: Wednesday, February 14, 2001, Time: 10:00:00 AM

Location: Aztec

Hambright, K, D, Kinneret Limnological Laboratory, Tiberias, Israel, kdh@ocean.org.il

Zohary, T, , Kinneret Limnological Laboratory, Tiberias, Israel, tamarz@ocean.org.il

Guede, H, , Institut fuer Seenforschung, Langenargen, Germany, hans.guede@lfula.um.bwl.de

EXPERIMENTAL ANALYSIS OF ZOOPLANKTON GRAZING AND PREDATION IN LAKE KINNERET

We quantified consumption by grazing and predatory macro- (greater than 150 um) and micro- (less than 150 um) zooplankton using natural Lake Kinneret plankton assemblages. Instantaneous mass-specific mortality rates due to grazing were prey size- and grazer size-specific. Micro-grazing yielded plankton mortality rates similar in magnitude to plankton growth rates, with mortality rates for bacteria and pico-phytoplankton greater than for nano- and net-phytoplankton. In contrast, macro-grazing yielded plankton mortality rates lower than plankton growth rates, with mortality rates for bacteria and pico-phytoplankton lower than for nano- and net-phytoplankton. Total consumption by micro- and macro-grazers amounted to 25 and 10 times, respectively, of grazer body carbon daily. Predation by cyclopoid copepods increased with prey size with mortality rates increasing from protozoans to rotifers and cyclopoid nauplii to cyclopoid copepodids to cladocerans. Total consumption by cyclopoids varied from 50-80% of body carbon daily. Our results highlight the need to modify our views of the relative importance of micro- and macro-grazers in eutrophic freshwater food webs.

This Session Listing

Aquatic Sciences Meeting, Albuquerque 2001

Quicklinks