Bacterial numbers, biomass and productivity in the Baltic Sea: a cruise study

Bacterial numbers, biomass and productivity were studied during 2 cruises in the Baltic Proper, Gulf of Finland and the Bothnian Sea. Bacterial populations in the open sea area had longer turnover times and lower productivity than in coastal areas, comparable to those found in the open ocean, but their biomass and abundance were as high as in the coastal areas of the Baltic Sea. High bacterial productivity in the aphotic water layer in the Gulf of Finland is suggested to indicate eutrophication of this area.