Tallinn-Helsinki transect; Tallinn-Lehtma transect;surveys near shallows Vinkov and Apollo

Primary production in the water column

CTD; autoanalysers

The distribution of phytoplankton in water bodies (including the Baltic Sea) is highly heterogeneous, both horizontally and vertically. Typical vertical separation of resources in the stratified Gulf of Finland in summer - light that is supplied from above and nutrients that are supplied from below - could lead to the development of a subsurface maximum. Subsurface maxima contain fine-scale layers ranging in thickness from a few centimetres to a few metres (known as 'thin layers') where densities of organisms are far greater than those above or below the layer, and as a result, thin layers may play an important role in the marine ecosystems. Subsurface maxima are often dominated by potentially toxic species of phytoplankton. The main goal of the project is to estimate the extent of the phytoplankton/chlorophyll a subsurface maxima layers in the Gulf of Finland through hydrophysical, -chemical and -biological measurements and analysis of meteorological parameters, and to determine favourable conditions/processes for their formation and to estimate the role of these layers in the pelagic ecosystem. The results allow to understand better the functioning of pelagic ecosystem of the gulf and to give an answer whether and how the subsurface maxima have to be taken into account when assessing the state, modelling the ecosystem and forecasting harmful algae blooms.

Department of Marine Systems at Tallinn University of Technology
MSI, Akadeemia tee 15a
Tallinn

12618
Estonia