Summary
Sewage discharge into near-shore marine ecosystems is one of the most common forms of contamination that occurs in Antarctica today, and is likely to impact on the biota living in these habitats. In this study the morphological responses of four species of Abatus heart urchins (A. philippii, A. nimrodi, A. ingens, and A. shackletoni) to sewage contamination from the Davis Station sewage outfall were examined. Three external measurements of the calcareous test dimensions, length, width and height, as well as test thickness and the width of the final growth sequence were collected from each individual, and a qualitative assessment of abnormalities in the test was conducted. Analysis of covariance, suggested in all cases that urchins from the outfall site had wider growth sequences, but thinner tests relative to urchins of the same size at reference locations. Abnormalities of the calcareous test were most frequent at the outfall site. A. nimrodi and A. shackletoni appeared to be the most sensitive species assessed to contamination, with 35% of individuals of both species at the outfall having some form of abnormality. Implications of these results are discussed in terms of biological monitoring in the region.