Spatio-temporal dynamics of the cyanobacterial blooms in the Gulf of Finland, Baltic Sea

Abstract

Summer cyanobacterial blooms, consisting mainly of the filamentous, nitrogen-fixing species, Aphanizomenon flos-aquae, Nodularia spumigena and Anabaena, are regular phenomena in the Baltic Sea. The Gulf of Finland is divided into several sub-basins which are separated from each other by quasi-stationary fronts related to the bottom topography and circulation patterns of the Gulf. The basins and fronts had their own characteristic bloom dynamics: wind-induced external energy inputs controlled bloom formation within the sub-basins, whereas the vertical, front-related transport processes had an additional impact on the bloom in front areas. Nutrient reserves and inorganic N:P ratios below the seasonal thermocline differed between sub-areas. -from Authors