| Abstract [eng] |
Nutrient loads (nitrogen (N), silica (Si) and phosphorus (P)) and their ecological stoichiometry (sensu Redfield) were analyzed along the Nemunas River-Curonian Lagoon (CL)-Baltic Sea continuum, and budgets were calculated. The mechanisms linking nutrient loads and the lagoon functioning were also analyzed by means of laboratory experiments. The results of the study suggest a significant drop in total P loads to the lagoon as compared to historical data, while N loads remain high. Interestingly, P loads showed limited interannual fluctuations, while N loads varied by 50 %, suggesting short-term control of their genesis and export. Despite P reduction, a regular, strong limitation of N and Si occurs in the summer, favoring the diatoms-cyanobacteria shift. Mass balance calculations suggest that large cyanobacteria blooms impact the nutrient retention capacity of the CL, due to large export of particulate matter and regeneration of nutrients from sediments, as confirmed by laboratory experiments. |
