On the relation of the dynamics in zooplankton abundance in the Baltic with phosphorus and Kattegat waters advection

Abstract

The relationship between the dynamics of the abundance of the crustacean plankton and the phosphorus concentration in the active (0-60 m) layer, and the advection of the Kattegat waters in the Baltic in the 1960-1977 are considered. It is shown that in spring (May) the abundance of the crustacean plankton is relatively poorly connected with the dynamics in phosphorus amount. It has distinctly been observed only in the years following warm winters (r=0.94, alpha =0,01) when phytoplankton vegetation begins early and the decrease in microalgae spring bloom is considerable. In summer and autumn clear and direct connections are observed between the abundance of crustacean plankton and phosphate concentration (r sub(1)=0,79, alpha sub(1)=0,01; r sub(2)=0,90, alpha sub(2)=0,01). The advection of Kattegat waters influences greatly the dynamics of biogenies promoting the outflow of nutritional salts from the deep-water layer. The effect of advection on the formation of productive zones (by zooplankton) is revealed the most distinctly in the Southern and North-Eastern Baltic in summer.