SUBLITTORAL EPIFAUNAL COMMUNITIES AT SIGNY ISLAND, ANTARCTICA .1. THEICE FOOT ZONE

Photographs were taken every 0.5 m along three transects of 5.5 m leng th on shallow rock faces at Signy Island, Antarctica, during the austr al summer of 1991/1992. The percentage cover of substratum ranged from 0 to 100% and the colonising communities included representatives of ten phyla. The zone from mean low-water neap level to 1.5 m depth was mostly devoid of organisms as a result of the seasonal formation of th e encrusting ice foot. Coralline and macroalgae dominated from 2 to 3 m, and animal groups from 3.5 to 5.5 m. Bryozoans, and to a lesser ext ent sponges, were the most abundant animal phyla. Within the bryozoans a succession of colonisation of different species was observed, the m ost abundant two of which occupied >80% of substratum in places. Subst ratum type seemed to be the main factor influencing community developm ent in the shallow sublittoral at Signy Island, although ice impact pr events community development in the top 1.5 m and limits it over the r est of the transect down to 5.5 m. Depth and profile of substratum als o influenced communities within this depth range (particularly taxonom ic composition).