BENTHIC FAUNAL ASSOCIATIONS ON SOFT SUBSTRATES AT POTTER COVE, KING-GEORGE-ISLAND, ANTARCTICA

Associations of benthic invertebrates from Potter Cove (Antarctica) we re defined from photo-transects. Density, percentage cover, species ri chness S', diversity index H', evenness index J' and mean-size estimat ions were studied in relation to water depth down to 30 m. A clear bat hymetric pattern was evident, with two different communities at 15 and 30 m, and a transition area between 20 and 25 m. At 15 m we observed a small number of taxa (nine in total), a high percentage of bare subs tratum (95%), and the dominant species were pennatulids and the bivalv e Laternula elliptica. From 20 to 30 m the dominant species was the as cidian Molgula pedunculata and there was a slight increase in S', H' a nd J', as well as in the mean size of individuals, especially in M. pe dunculata, while the proportion of bare substratum showed a constant d ecrease with depth. Using multivariate analyses, three faunal assembla ges related to depth were defined and a strong association of some spe cies, mainly predators and opportunistic necrophages, with M. peduncul ata was revealed. Ice impact (icebergs and anchor ice) seems to be the major regulating factor of benthic assemblages in shallow waters.