Winter Zooplankton in a Small Arctic Lake: Abundance and Vertical Distribution

Vladimir G Dvoretsky,Alexander G Dvoretsky

doi:10.3390/w13070912

Abstract

Zooplankton assemblages are of great importance in aquatic food webs because they link lower (microplankton) and higher trophic levels (top predators). Small water bodies in the Arctic regions of Russia are less studied in winter because of severe ice conditions. For this reason, we analyzed the winter zooplankton community in Lake Kulonga (western coast of Kola Bay, Barents Sea). A total of 9 taxa were found in the samples. The total abundance varied from 200 to 1320 ind. m−3, averaging 705 ind. m−3. The total zooplankton biomass was 1.8–72.8 mg of wet mass m−3 with an average of 30 mg m−3. These parameters were lower than in other Russian Arctic and sub-arctic lakes in summer. Old copepodites of Cyclops spp. dominated the zooplankton community at deep-water stations in terms of the total abundance consisting of 24–33%. The copepod Macrocyclops albidus prevailed in terms of the total zooplankton biomass comprising 30–33% at deep-water stations while Cyclops scutifer and copepodites Cyclops spp. had the highest biomass at shallow water stations. Vertical distribution demonstrated different patterns at neighboring stations, probably as a result of differences in the density of fish predators.

Highlights

Arctic Lake: Abundance and VerticalThe significance of plankton for freshwater, brackish, and marine ecological systems is unquestionable [1,2,3,4]
Old copepodites of Cyclops spp. dominated the zooplankton community at deep-water stations in terms of the total abundance consisting of 24–33%
The aim of this paper is to report the species composition, abundance, biomass, and the vertical distribution of the zooplankton community in Lake Kulonga in winter as a basis for further water quality assessment of this lake under anthropogenic pressure

Summary

Introduction

Arctic Lake: Abundance and VerticalThe significance of plankton for freshwater, brackish, and marine ecological systems is unquestionable [1,2,3,4]. Because many Copepoda, Cladocera, and Rotifera are filter-feeding organisms with relatively short lifespans and their taxonomical identification is easier than in the case of phytoplankton, zooplankton assemblages may be considered as good biological indicators of environmental conditions and shifts of hydrological regimes in freshwater ecosystems [9]. Their composition and abundance may reflect changes in aquatic environments under modern climatic fluctuations and anthropogenic impacts [10,11]. The trophic structure of zooplankton in Arctic lakes is considered to be simple compared to boreal waters [13,14]

Objectives

Methods

Discussion

Conclusion