Factors regulating summer phytoplankton in a highly eutrophic Antarctic lake.

MATALONI, G.; TESOLÍN, G.; SACULLO, F.; TELL, G.

HYDROBIOLOGIA

Springer

Lugar: Netherlands; Año: 2000 p. 65 - 72

0018-8158

Lakes from Maritime Antarctica are regarded as systems generally inhabited by metazoan plankton which would be capable of imposing a top-down control on the phytoplankton during short periods, while lakes from Continental Antarctica lacking these communities would be typically controlled by scarcity of nutrients, following a bottom-up model. Otero Lake is a highly eutrophic small lake located on the NW of the Antarctic Peninsula, which has no metazoan plankton. During summer 1996, we studied the abundance, composition and vertical distribution of the phytoplanktonic community of this lake with respect to various abiotic parameters and the microheterotrophic community. Our results demonstrated neither nutrient limitation nor any significant plankton loss to the outflow. Moreover, it is the remarkably high density of ciliates (up to 1775 ind. ml-1) which seems to be controlling the abundant phytoplankton, dominated by Chlamydomonas aff. celerrima Pascher, through heavy grazing.