The relationship between the distribution of plankton biomass and plankton communities in the Drake Passage and the Bransfield Strait (BIOMASS-FIBEX, February-March 1981)

In the investigated area of ca. 79 thousand (miles)^2,krill biomass, as designated by Data Workshop 1981 in Hamburg, makes up about 17% of zooplankton wet weight in the surface 100m water layer. Based on our own hydroacoustic measurements over an area of 48 thousand (miles)^2,krill biomass there makes up about 44% of the total zooplankton biomass. Three plankton communities with distinct trophic relations and the dominance of certain taxa have been distinguished in the area investigated. The "continental" community comprises phytoplankton with large quantities of flagellata, small phytoplankton consumers, predatory Cyclopoida, krill, carnivorous Parathemisto, and also larvae and young Channichthyidae. The "antarctic" community contains planktonic diatoms, Radiolaria, phytophagous Calanoida, Pteropoda and carnivorous Chaetognatha. The "intermediate" community is completed by Appendicularia, naupli, krill larvae, predacious Polychaeta and immature Nototheniidae. The distribution of plankton communities and plankton biomass in the research area may provide biological indicators for the intensity of water inflow from the Weddell Sea