Keywords: Baltic Sea, airborne nitrogen, nitrogen load control, air quality, air pollution, atmospheric dispersion modelling, nutrient deposition, eutrophication, phytoplankton blooms, chlorophyll–a, bloom length, bloom intensity, water pollution
Origin and possible effects of episodic nutrient deposition events over the Baltic Sea
HELCOM has defined eutrophication as the greatest threat to the Baltic Sea environment. The focus of the paper is the identification of the possible geographical areas from where the airborne nitrogen deposited to the Baltic Sea sub–basins during main episodic events is emitted. While the nitrogen compounds are long–lived, one goal was to check if those sources are located on the Baltic Sea drainage basin, where most of the nitrogen load control actions are required to be made in order to reduce harmful effects of eutrophication of the sea. Additionally, the possible influence of airborne nutrient load on the spring phytoplankton blooms is studied by looking for causal relationships of deposition events and chlorophyll–a concentrations (bloom intensity and length) over the Gulf of Finland and the Baltic proper.