Using benthic recruitment to assess the significance of contaminated sediments: the influence of taxonomic resolution.

The use of small-scale experimental units as a means of evaluating the ecological effects of contaminated sediments was examined at the species, family, mixed and phylum levels of taxonomic resolution. Sediments were taken from various locations representing a range of contaminant loads. Containers with these sediments were placed in situ at a relatively uncontaminated location for 90 days. The containers were retrieved and the abundance of the macrofauna which recruited to the containers was estimated. The results showed that the composition of the benthic communities in the more highly contaminated sediments differed significantly from those in less contaminated sediments. Analyses at the different taxonomic levels showed that all but the phylum level data showed some differences in community structure among sediment types. The study showed that small-scale experiments are useful for examining the effects of contaminants and that higher levels of taxonomic resolution can be used to describe variations in the structure of benthic communities at this spatial scale.