SOME PECULIARITIES OF SPATIAL DISTRIBUTION OF LAND-BASED INORGANIC NUTRIENTS IN THE COASTAL PART OF THE BALTIC SEA

Abstract

The Baltic Sea is a semi-enclosed sea with remarkable cyclonic circulation. The most attention must be paid to the local-scale factors playing the significant role in the overall figures. Fresh water inflow takes the majority of the mass budget income thus enabling local streams. The bathymetry of the Lithuanian Baltic zone is lowering gradually towards the open sea and has no significant deeps or depths. As the little exception there is a deeper basin, which stretches from the Curonian Spit until it reaches the approaches of the Southern Gotland Deep. The long-term investigations of spatial seasonal distribution of inorganic nutrients (nitrite, nitrate and orthophosphate) resulted to some regularities depending on prevailing wind scale duration and force. The results obtained during the experiment showed the complicacy of field structure. Extremely heterogeneous patterns of nutrients are formed when northern or eastern winds or breezes are prevailing. After the other wind directions significant decrease of heterogeneity was observed. Assessment showed that Curonian Lagoon water entering the Baltic Sea is enriched with dissolved inorganic nitrogen 6 times more and dissolved inorganic phosphorus concentration is higher by 2 times in comparison to the open sea values in winter.