СЕЗОННАЯ ИЗМЕНЧИВОСТЬ ПЕРВИЧНОЙ ПРОДУКЦИИ И СОСТАВА ФИТОПЛАНКТОНА В БЕРЕГОВОЙ ЗОНЕ РОССИЙСКОГО СЕКТОРА ГДАНЬСКОГО БАССЕЙНА БАЛТИЙСКОГО МОРЯ

From April 2008 to until April 2009 we investigated the seasonal dynamic of primary production in the coastal zone of the south-eastern Baltic Sea. The predominant limiting factor for diatoms and dinoflagellates spring bloom was nitrate. During the nitrate-limited period, increase of ammonium due to mineralization of organic matter can temporarily change the prevailing N-limitation for phytoplankton grow into a P-limited phase. Nitrate and phosphate concentrations reached minimum values in mid-summer, almost below detection limits (0,07 mmol/m3 NO3, 0,06 mmol/m3 PO4). Moderate influence of continental run off with the peak runoff during of the spring-summer minimum of phytoplankton grow on primary production was observed: its annual value reached to the eutrophic level (290 gC·m-2·year-1), however the seasonal dynamic type was typical for mesotrophic waters of northern middle latitudes.