EFFECTS OF METAL CONTAMINATION ON MACROBENTHOS OF 2 NORTH-SEA ESTUARIES

Time series of faunal data for the Tyne (1978-1989) and the Tees (1981 -1992) estuaries were analysed using Bray-Curtis similarity indices an d dendrogram plots, multidimensional scaling, and principal components analysis (PCB). These data show that benthic community structure chan ged during the 1980s. Data on sediment heavy metal concentrations in t he Tees estuary For the period 1971-1986 show significant reductions i n contamination across this period, and also between-station differenc es. PCA of faunal data showed grouping of stations into marine, estuar ine, and contaminated clusters. PC axis 1 appeared to be controlled by position of sampling site in relation to sources of contamination, an d PC axis 2 by salinity. However, sediment metal concentrations were n ot significantly correlated with PC axis 1 scores. Reasons for this ar e discussed. Changes in the benthos indicate improving environmental q uality, suggesting that clean-up initiatives in both estuaries have be en effective. (C) 1996 International Council for the Exploration of th e Sea