Bacterial community structure influenced by Coscinodiscus sp. in the Vistula river plume* This research was carried out with the support of a grant from the Polish Ministry of Science and Higher Education (No. NN304 025334) and statutory activities of the Department of Fisheries Oceanography and Marine Ecology of the National Marine Fisheries Research Institute (project P1-2).

Abstract

The Gulf of Gdańsk is influenced by freshwater inflow from the River Vistula and by a wind-driven current along the coast. Bacterial communities from five stations along a salinity gradient were sampled during one day and analysed by terminal restriction fragment length polymorphism (T-RFLP), catalysed reporter deposition-fluorescence in situ hybridisation (CARD-FISH) and 16S rRNA gene libraries. On the day of sampling, we observed a probable current-driven seawater influx into the inner part of the gulf that separated the gulf into distinct water bodies. Members of the diatom Coscinodiscus sp. dominated one of these water bodies and influenced the bacterial community. The coexistence of typically freshwater and marine bacterioplankton populations in the Vistula river plume suggested an integration of some freshwater populations into the Baltic Sea bacterioplankton.

Keywords

• Baltic Sea
• Bacterioplankton
• Coscinodiscus sp
• T-RFLP
• Clone library