Diatoms from a hot spring in Lake Tanganyika

Diatoms from an underwater hot spring in the northern basin of Lake Tangany ika were studied. Only 19.5% of the frustules observed were living cells, b elonging to 19 diatom tare. Four taxa, belonging to the genera Caloneis, Di ploneis and Sellaphora were dominant; the other taxa occurred at frequencie s less than 2%. The two abundant Caloneis taxa, C. bacillum var. fontinalis and C, ventricosa f. peisonis have not previously been reported from Lake Tanganyika, nor from the other East African Great Lakes. Morphological desc riptions and light and electron micrographs are presented of the four domin ant taxa living in the hot spring: Caloneis silicula f. peisonis, Caloneis bacillum var. fontinalis, Diploneis subovalis and Sellaphora pupula.