Phytoplankton development in both 1994 and 1995 was unusual. In 1994, the
bloom of P.gatunense started in January, reached a record high biomass in
March-April, and declined in June. The 1994 annual average of the dinoflagellate
biomass was 87.3 g nr2
, -70% higher than that observed in 1993 (51.5 g nr2
).
The multi-annual average of dinoflagellate biomass (1969-1993) was 51 g m~2
.
Following the Peridinium bloom, the diatom Cyclotella polymorpha (Meyer and
Hakansson, 1996) developed in June, accompanied by the desmid Closterium
acutum var. variabile and Synedra (= Fragilaria) ulna. Cyclotella became rare in
July when an outgrowth of the diatom S.ulna occurred.