ЗООПЛАНКТОН ПЕТРОЗАВОДСКОЙ ГУБЫ ОНЕЖСКОГО ОЗЕРА В ПОДЛЕДНЫЙ ПЕРИОД
UNDER ICE ZOOPLANCTON OF PETROZAVODSK BAY OF ONEGO LAKE

Summary/Abstract: A detailed study of the under-ice zooplankton in Petrozavodsk Bay of Onega Lake was made in the frames of the project “Lake Ladoga: Life under ice” in March of 2015 and 2016. The winter zooplankton was characterized by scarce species composition (24 species) and low quantity (0,5 th. ind./m3 and 0,016 g /m3). The basis of its numerical strength (91 %) and biomass (98 %) was presented by adult copepods and their nauplial stages. The zooplankton biomass in the water column increased with the depth of the water and decreased in the coastal zone. The vertical distribution of zooplankton and its some species has been studied. The zooplankton characteristics significantly differed by years. The phase of convective mixing was observed in 2015; in contrast, in 2016 it was not registered, which was conditioned by the shift in the thermal regime phase. The composition, structure and numerical strength of the studied zooplankton have not changed since the 60s of the last century, which indicates its functioning stability.

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