Epifaunal communities in Potter Cove, King George Island, Antarctica

RICARDO SAHADE; MARCOS TATIÁN; JENS KOWALKE; STEPHAN KHÜNE; GRACIELA ESNAL

POLARFORSCHUNG

Año: 1998 p. 123 - 132

0032-2490

Sub-littoral benthic ecology in Antarctica is a relatively new field of research. The majority of early studies, were rnade On systematics and On deep-water benthos. During the last two decades, quantitative analyses of the Antarctic benthos have been carried out in various regions (Barthel and Gutt 1992, Dayton et al. 1974, Gallardo et. al 1977, Gerdes et al. 1992, Kirkwood and Burton 1988, Mühlenhardt-Siege1 988, Saiz-Salinas et al. 1997). One of the emergent features of these works, is the richness in terms of diversity and biornass of Antarctic benthos, especially in shallow waters. Another peculiarity is the widespread dorninance of sessile epifaunal groups rnainly sponges (Dayton et al. 1974). But polychaetes, molluscs, echinoderms and crustaceans can dominate as well (White 1984, Starmans 1997). However comparisons of all results is usually difficult because of the use of different sampling methods (dredges, trawls, prers, photographs, etc.) and parameters (biomass as wet weigth or dry weigth, densities, percentaje Cover etc.). Althougth the study of the community structure along a natural environmental gradient may not provide conclusive insights into the processes that form this pattern, it is a necessary step before studies can be undertaken to reveal the processes themselves (Turon 1990). A variety of factors have been proposed to influence the comrnunity structure in Antarctic benthos. The principal ones are substrate type, physical disturbs caused by ice action, phytoplancton biomass, predation, competition, oxygenation, current speed, and pollution (Dayton et. al 1970, Dayton and Oliver 1977, Hedgpeth 1969, Kirkwood and Burton, Platt 1978, Sahade et al. 1998). The aim of the present study is to describe the benthic community structure in Potter Cove in relation to physical factors as depth and substrate types, and to discuss about the principal factors that may determine the observed patterns.