Interaction effects of N:P ratios and frequency of nutrient supply on the plankton community in the northern Baltic Sea

摘要: An experiment was carried out in brackish seawater mesocosms to investigate the impacts of different N:P ratios and frequency nutrient supply on phytoplankton zooplankton communities Archipelago Sea, part northern Baltic Sea. The used a 2 × factorial design which nitrogen (N) phosphorus (P) were added either an N-deficient or Redfield ratio daily at 1 wk intervals. Both total biomass most groups increased enrichments with ratio. effect addition frequencies varied time between ratios. heterocystous N2-fixing cyanobacteria highest enrichment, while chloro- phytes weekly treatment. concentration cyanobacterian hepa- totoxins during experiment, but not affected by enrichments. bio- mass calanoid copepods more than when nutrients supplied Small rotifers, other hand, favored especially daily. Based results this study it seems that favors cyanobacterial growth, intermittent heavier discharge may result advantageous plankton community, fewer community dominated larger species.