Presence and genetic diversity of microcystin-producing cyanobacteria (Anabaena and Microcystis) in Lake Kotokel (Russia, Lake Baikal Region)

A survey was conducted for the presence of cyanobacteria toxins in Lake Kotokel due to a few cases of Haff disease registered in 2008-2009 caused by consumption of fish from Lake Kotokel, and wildlife mortality including large fish kill. The aims of this study were to determine what cyanotoxins (if any) were present in the lake, to describe phytoplankton composition including morphology, density, and species diversity of cyanobacteria, as well as to evaluate the trophic state of the lake. Samples were collected from both nearshore and central sites in August of 2009. Aphanocapsa holsatica dominated the phytoplankton. The presence of toxigenic genotypes of Microcystis spp. and Anabaena lemmermannii was detected by sequencing of PCR-amplified aminotransferase domain of microcystin synthetase gene. LR, RR, and YR microcystin (MC) variants were detected with liquid chromatography-UV mass spectrometry. The data do not shed light on the etiology of Haff disease in Lake Kotokel region, nevertheless taking into account the recreational importance of the lake and its direct connection to Lake Baikal, a necessity to monitor cyanobacteria in these water bodies is evident. This is the first report on simultaneous detection of MC-producing genotypes and MCs in the Lake Baikal region.