Phytoplankton composition and seasonal succession in 1995 were also unusual.
In January, there was a brief outgrowth of the diatom Aulacoseira granulata,
followed by a bloom of Microcystis aeruginosa. These cyanobacteria peaked in
March (54.5 g m~2
) and declined in mid-April. Microcystis was accompanied by
high numbers of Cryptomonas spp. The decline of Microcystis was followed by an intense bloom of P.gatunense, which reached an unusually high peak (329.5 g
m~2
) in May and decreased rapidly in June. The dinoflagellates were accompanied
by chlorophytes, especially Oocystis spp.