The aim of this study was to identify the influence of copper pollution on benthic copepod populations by means of dosing seabed sediments with copper. Superficial muddy sediments were removed from a shallow subtidal experimental site on the west coast of Scotland and dosed with copper powder to produce nominal dry weight concentrations of 0, 50, 500, and 5000 µg/g sediment. Four replicate 100 cm3 polycarbonate bottles were filled with spiked sediment for each concentration, and the bottles were implanted into the seabed at the experimental site. After 1 mo, the bottles, together with replicate core samples from the untreated background sediment, were collected, the meiofauna was extracted using colloidal silica, and the copper concentration was measured. In relation to the controls, copepod abundance was significantly depressed in the high-copper treatment. Composite diversity indices (Shannon-Wiener and Simpson's) and evenness failed to exhibit any copper-induced changes, although the number of species and genera were depressed at the highest concentration. Differences in the responses of copepods to copper were found between copepodites and adults and among different species. In general, the dominance of Tachidiella minuta and species of Halectinosoma and Longipedia in the control and low copper concentrations was replaced by dominance of species of Cletodes, Laophonte, and Stenhelia at the higher concentrations. The abundance of Cletodes longicaudatus was significantly enhanced in the high-copper treatment. The only statistical evidence for an impact of copper on the copepod assemblage at levels lower than the high treatment was revealed by applying the multivariate test ANOSIM (analysis of similarities) to the copepodite abundance data at the generic level, with the copepodite assemblage in the medium treatment being of a significantly different composition to that in the controls. Results are discussed in relation to other studies on the impact of pollution on the meiofaunal taxa, the likely mechanisms bringing about the observed changes, and the validity of this in situ approach.
|Number of pages||16|
|Publication status||Published - Apr 2004|