Distribution of polychaetes in the shallow, sublittoral zone of Admiralty Bay, King George Island, Antarctica in the early and late austral summer ()
ABSTRACT
This study assessed the spatial distribution pa- ttern of soft-sediment polychaetes on the near-shore of Admiralty Bay, King George Island, Antarctica. In the early and late summer of 2003 /04, seven sites at three different depths (20,30 and 60 meters) were sampled using a van Veen grab. 8,668 individuals all told, belonging to 67 species and 23 families, were identified. The families Terebellidae, Syllidae and Maldanidae were the most speciose. Mean densities ranged from 45.2 to 388.1 ind. 0.1 m-2 in the early summer, and from 29 to 183 ind.0.1m-2 in the late. The species Aphelochaeta cincinnata, Levinsenia gracilis and Rhodine antarctica were the most frequent and abundant. Initially, mean biomass ranged from 0.11 to 5.27 g.0.1 m-2, in the early season and from 0.35 to 5.86 g.0.1 m-2 towards the end. Aglaophamus trissophyllus, Eupolymnia sp. and Barrukia cristata were the species with the highest biomass. Polychaete taxocoenosis structure remained similar in both periods. In the early summer, mean densities, biomass and number of species were lower at 30 meters and higher at 60, whereas in the late, these differences were higher among transects. Ice impacts, mainly anchor-ice, in the early summer, as well as icebergs later on, most likely caused the differences encountered.