A field technique for the determination of zooplankton grazing on natural bacterioplankton

Abstract

SUMMARY. 1. A method for the determination of zooplankton community grazing rates on natural populations of bacteria is described. 2. Undisturbed zooplankton samples were incubated with 3 H‐thymidine‐labelled bac teriioplankton, and animals and their food subsequently separated by size. 3. Prehandling of zooplankton by concentration before incubation reduce the grazing rates by a factor ranging from three to four. 4. Time series experiments showed that appropriate incubation periods ranged from 40 min at 14°C to 60 min at 10°C. 5. Spatial variability in the zooplankton was the main source of the overall standard error. This was considerably reduced by using composite samples.