Acta Univ Latv (2007) 723: 61–69

Zooplankton indicators of trophy in Latvian lakes

Abstract

Studies on the relationship between zooplankton taxonomic composition and environment characteristics are an important issue in the evaluation of the ecological quality of lakes. Data were collected in 1998 - 2004 in 113 lakes of different types. Zooplankton samples were taken simultaneously with the hydrochemical and phytoplankton samples, and field measurement of physical parameters. Redundancy Analysis was used to ordinate zooplankton abundance data against environmental variables, and General Linear Models and XY(Z) plots were used to test and visualize these relationships. A number of taxa increased in abundance with eutrophication, while results on using of zooplankton organisms as low trophy indicators were poor. However, an indirect adverse effect of increased nutrient concentrations through algal blooms was suggested.