The relationship between trace metal contamination and stream meiofauna

The effect of chemical contaminants on freshwater meiofaunal communities is poorly understood and meiofauna rarely form part of environmental impact a ssessments in fresh waters. The community composition and diversity of meio fauna in streams of southwest England (Cornwall) representing a gradient in trace metal contamination were investigated. Multivariate and univariate s tatistical techniques were used to correlate community composition, diversi ty and environmental variables. Meiofaunal communities were very different at sites with high compared with low metal concentrations. Copper, either s ingly, or in combination with other environmental variables (aluminium, zin c or dissolved organic carbon), was the most important correlate with commu nity composition. Not all meiofaunal species were adversely affected by met als, however, and some taxa, most notably certain cyclopoid copepods, were abundant at high metal concentrations. Moreover, sites with high metal conc entrations were not significantly less diverse than sites of low metal conc entrations. These data suggest that metal contamination significantly alter s the composition of stream meiofaunal assemblages and highlight the import ance of including meiofauna in impact studies of fresh waters. (C) 2000 Els evier Science Ltd. All rights reserved.