Structure and Trophic Characteristics of Zooplankton Communities of the East Siberian Sea

Abstract

Abstract Research on the structure and trophic characteristics of zooplankton communities of the East Siberian Sea (ESS) was performed within the program “Marine Ecosystems of the Siberian Arctic” during cruise 69 of the R/V Akademik Mstislav Keldysh. The material was collected on two quasimeridional transects conducted in the latitudinal range ~71°00′–75°30′ N from the inner shelf adjacent to the Indigirka and Kolyma outfalls to the outer shelf during September 5–9, 2017. The list of species and larger taxa, as well as their biomass and trophic characteristics, are presented, and the peculiarities of cross-shelf distribution in relation to the conditions of the pelagic environment are described. The obtained estimates of the mezoplankton biomass in the ESS are on the whole within the range typical of the rest of the Siberian Seas in summer–fall. It has been established that mezoplankton communities of the western and eastern ESS significantly differ in quantitative characteristics, the role of dominant species and taxonomic groups in biomass, grazing impact of mesoplankton on the phytoplankton biomass and production, and features of the cross-shelf distribution of these characteristics. The boundary between the communities with different structural functional characteristics is located approximately at 160°–163° E. A conclusion is made that analysis of climatic and seasonal changes in ESS mezoplankton should be examined with allowance for the principal differences between pelagic biotopes and communities of the western and eastern parts of the basin.