Live sieving of freshwater zooplankton: A technique for monitoring community size structure

Abstract

A simple method is described for a quick determination of the size structure of zooplankton communities. This is based on sieving of a live sample, using one or two sieves of known mesh size, and determining the dry weight of the size fractions. Size separation by live sieving is validated statistically on Daphnia galeata, a common planktonic cladoceran, by comparing size-sieved fractions against direct microscopic measurements of individuals. A non-linear model was used for assessment of sieving statistics. The sieving technique facilitates the gathering of size-structured biomass data for zooplankton for routine monitoring or long-term studies.