Epilithic biomass in an outflow stream at Potter Peninsula, King George Island, Antarctica

Abstract

The epilithic biomass of an outflow stream at Potter Peninsula (King George Island, Antarctica) was studied from November 1996 to February 1997 by means of chlorophyll a concentration, dry weight and ash-free dry weight. The Autotrophic Index and the Lakatos classification were also used in order to characterize the epilithic community. Several physical and chemical parameters were analyzed. Snow and ice melt greatly increased water flow through Tres Hermanos Lake and in the stream. Chlorophyll a concentrations fluctuated between undetectable and 3.5 μg cm−2 with a marked increase, which averaged 3 orders of magnitude, towards the end of the study period. Dry weight ranged between 299.9 and 13,118.7 μg cm−2 and ash-free dry weight between 70.8 and 996.9 μg cm−2. According to the Autotrophic Index and the Lakatos classification, the epilithon of the stream had a low mass with low organic component and large amount of inorganic sediment. The organic matter comprised a low proportion of chlorophyll a and a major proportion of probably detritus or bacteria, rather than fauna.