Effects of copper contamination on recolonisation of subtidal marine soft sediments - an experimental field study

Recolonisation patterns of soft-bottom macrofauna on defaunated Cu-spiked s ediments were studied in a field experiment at 63 m depth in the Oslofjord, Norway. Field experiments studying colonisation patterns of contaminated s ediments are ecologically relevant since settling and metamorphosis of pela gic larvae are generally considered the most critical phases in the develop ment of marine benthic assemblages. Total faunal abundance and the density of the polychaetes Pectinaria koreni and Prionospio cirrifera decreased sig nificantly at sediment Cu-concentrations of 300 mg kg(-1). Also the polycha etes Pseudopolydora pancibranchiata, Capitella capitata, Chaetozone setosa, Harmothoe spp., the bivalve Thyasira sar si and the brittlestar Ophiura af finis were significantly negative correlated to increased sediment Cu-conte nt, Although these species were affected negatively, most of the 116 taxa w ithin the experimental trays showed no response over the entire range of Cu sediment concentrations. Most field studies on recolonisation have been pe rformed in the intertidal or shallow subtidal, These environments are often dominated by robust organisms while animals living in deeper waters are mo re sensitive to disturbance. The experimental system developed could easily be used at depths between 20 and 100 m to study effects of toxic compounds separately or as mixtures, or colonisation and succession processes of unc ontaminated sediments in general. (C) 1999 Elsevier Science Ltd. All rights reserved