Structure and ecology of the flagellate Scourfieldia caeca (Korsh.) Belcher & Swale in two meromictic lakes in Tasmania

Abstract

The minute green flagellate S. caeca occurs in large numbers in two dystrophic meromictic lakes in Tasmania, constantly occupying a narrow stratum immediately above the chemocline, where physical and chemical conditions change dramatically with depth and where available light is less than 1% of surface radiation and restricted to red wavelengths. In its ultrastructure, S. caeca resembles cultured material described previously but differs in the structure and size of its chloroplast and in the structure of its diagnostic keel of starch.