Biogeochemical Budgets of Nutrients and Metabolism in the Curonian Lagoon (South East Baltic Sea): Spatial and Temporal Variations

Estuaries are biogeochemical reactors able to modulate the transfer of energy and matter from watershed coastal zones retain or remove large amounts terrestrially generated nutrients. However, they may switch nutrient sink source depending upon interannual variability supply internal processes driving whole system metabolism (e.g., net autotrophic heterotrophic). We tested this hypothesis in Curonian Lagoon, a hypertrophic estuary located south east Baltic Sea, following budget approach developed Land-Ocean Interactions Coastal Zone (LOICZ) project. Annual budgets for nitrogen (N), phosphorus (P), silica (Si) were calculated 2013–2015 period. The lagoon was divided flushed, loaded area, confined, less area. always dissolved inorganic Si P whereas it N confined dominated by denitrification, flushed due dinitrogen (N2) fixation. ecosystem (NEM) indicated that Lagoon mainly because high primary production rates. In turbid system, low N:P ratio, summer temperatures, calm weather conditions support N2-fixing cyanobacteria, suppressing estuarine N-sink role.