Ecotoxicological studies of the effects of heavy metals and hydrocarbons on Antarctic and temperate echinoderms

Contamination of Antarctic marine environments with heavy metals and hydrocarbons has occurred as a result of human habitation and activities over the past 100 years. Despite a commitment by Antarctic Treaty Nations to minimise environmental harm and remediate existing contaminated sites, there is insufficient data on the sensitivities of Antarctic marine species to set priorities or targets for clean-up efforts or to establish guidelines for water and sediment quality. As a pre-requisite to collecting these data there is need for relevant and practical toxicity testing protocols for Antarctic species. Morphological deformities of Abatus spp. heart urchins from contaminated sites were quantitatively investigated. Urchins from the contaminated sites were found to be smaller, flatter and wider, particularly those from the inshore areas closest to the contamination source. Obvious deformities occurred in nearly 50% of the inshore urchins. Metal concentrations in carbonate tests of urchins from these sites appear to correlate with the observed morphological differences. Techniques for the larval culture of echinoids with planktonic larvae are well developed, however culture of brooding species has not previously been described. Methods were developed for the collection, maintenance and transport of juvenile Abatus spp. with juveniles that were removed from the brood pouch and then reared for one year. This work has potential application to a range of biological and toxic iological studies of brooding echinoids. Juvenile Abatus ingens and A. nimrodi urchins were exposed to metals in seawater for 10 days. Copper and zinc caused mortality at concentrations affecting larval development in other echinoid species. In particular copper was toxic within concentration ranges that may occur in contaminated Antarctic marine environments. To assess accumulation of metals by heart urchins, the temperate species Echinocardium cordatum were exposed to sub-lethal concentrations of lead and copper in sediments for 60 days. Chemical analysis of the carbonate shell at the end of this period showed increased concentrations of copper in exposed animals, although results varied between and within individuals. Results of high resolution elemental analysis suggest that the incorporation of metals occurs throughout the carbonate test and not only in newly deposited shell material. The toxicity of diesel in sediments to the Antarctic ophiuroid Ophiura crassa and to the temperate urchin Echinocardium cordatum was examined over 10 days. Undispersed diesel impacted on ophiuroid movement within 24 hours although the effects were reduced over a longer period. Dispersed diesel was more toxic than undispersed diesel to ophiuroids, causing high rates of mortality. E. cordatum was not tested with dispersed diesel, but was far more sensitive to undispersed diesel than 0. crassa, with mortality of all exposed animals at concentrations 42 mg diesel kg dry sediment-1 . The methods for culture and toxicological testing described in this thesis have potential application to other related echinoderm species and toxicants. The results of the studies have relevance to the development of water and sediment quality guidelines for Antarctica.