Typology of lentic water bodies at Potter Peninsula (King George Island, Antarctica) based on physical-chemical characteristics and phytoplankton communities

Abstract

During austral summer 1995/1996, 26 ultraoligotrophic to hypereutrophic ponds and lakes on Potter Peninsula (King George Island, Antarctica) were characterized on the basis of abiotic factors and the phytoplankton community. The influence of vegetation and animal presence in the catchment, morphometric variables of the water bodies and their proximity to the sea on composition and abundance of phytoplankton was also considered. Results of a Principal Component Analysis show that the characteristics of each catchment strongly influenced the abiotic parameter accounting for the obtained lake and pond ordination. In particular, five groups of water bodies were clearly defined primarily based on nutrients and suspended solid concentrations, and to a lesser extent on pH and conductivity. These groups could be classified into two assemblages distributed along a phytoplankton biomass gradient, which is regulated by the light availability in one case and by nutrient concentrations in the other. Among 140 algal taxa registered, 3 were new records for Antarctica and 18 taxa were new records for Potter Peninsula. Bacillariophyceae was the dominant class in terms of species number and density. Chlorophyta and Cyanobacteria were subdominant. The tychoplanktonic habit was the best represented in almost all lakes.