Variability of trace-metal concentrations within and between colonies of Pocillopora damicornis

Variations of cadmium, lead, copper, nickel and chromium concentrations in tissues and skeletons of the scleractinian coral Pocillopora damicornis wer e measured to provide information for designing bio-assay surveys involving this organism. Intra-colony variations were measured using multiple portio ns from individual colonies, and inter-colony variations were measured usin g single portions from different colonies of a coral community. We found th at specific metals partitioned differently into tissue and skeletal parts, possibly because selectivity for each metal differed due to biochemical uti lity or toxicity. Intra-colony variations in metal concentrations were inco nsistent, and skewed distributions of tissue-metal concentrations were some times observed. Overall, the application of tissues for heavy-metal bio-ass ays is compromised by inconsistent intra-colony variation, and the substant ial material needed to represent tissue-biomass. In contrast, small replica te samples of skeleton can be collected from a colony, allowing representat ion of intracolony metal variation with minimal damage to the organism. (C) 2000 Elsevier Science Ltd. All rights reserved.