Investigating lethal and sublethal effects of the trace metals cadmium, cobalt, lead, nickel and zinc on the anemone Aiptasia pulchella, a cnidarian representative for ecotoxicology in tropical marine environments

The zooxanthellate sea anemone Aiptasia pulchella is found throughout the tropical and subtropical oceans of the Indo-Pacific and is easily maintained in aquaria, posing potential suitability as a standard tropical marine test organism for use in ecotoxicology. To gain an understanding of the sensitivity of A. pulchella to trace metals, 96-h static-renewal toxicity tests were conducted. Values of 96-h LC50 between 946 and 1196 mu gL(-1) were estimated for cadmium, between 595 and 1146 mu gL(-1) for zinc, 8060 and 12 352 mu g L-1 for lead and 2209 and 5751 mu g L-1 for nickel. In addition, preliminary assessment of rapid tentacle retraction was made. Six-hour EC50 values of 355 and 979 mgL(-1) for cadmium, between 384 and 493 mu g L-1 for zinc, between 2340 and 2584 mu g L-1 for nickel, and 2610 mu g L-1 for lead, were estimated for 'severe' tentacle retraction. Cobalt concentrations up to 1547 mu g L-1 caused extreme zooxanthellae loss, but no more than 10% mortality and no rapid 'severe' tentacle retraction. The present study has provided important baseline information, enabling comparison of the acute sensitivity of A. pulchella to trace metals with other marine invertebrates, and guiding the development of sublethal endpoints.