Assessment of Freshwater Bodies in Murmansk in Terms of Composition of Aquatic Invertebrates

Abstract

The paper presents the results of analysis of hydrobiological samples of freshwater bodies of Murmansk (Lake Okunevoe, Lake Ledovoe and Lake Semyonovskoe). The number, degree of dominance and frequency of occurrence of organisms are determined. In Lake Ledovoe, the dominant species represent small organisms with simple life cycles and a high rate of reproduction. The taxonomic composition of water invertebrate community in the Lake Ledovoe highlights features of anthropogenic eutrophication. Several dominant species stand out in the ciliatocenosis of the Lake Okunevoe. The species diversity of micrzooplankton community is higher than in the Lake Ledovoe. In general, the Lake Okunevoe can be characterized as a water body with signs of ecosystem stability damage. The hydrobiocenoses of the Lake Semyonovskoe has the greatest species diversity. However, it is characterized by the tendency to decrease the species composition of organisms – indicators of clean waters. There are initial signs of anthropogenic eutrophication of the Lake Semyonovskoe. The waters of the studied lakes are characterized as β-mesosaprobic (moderately contaminated). It is generally noted that the fauna of water bodies is characterized by small species diversity. In lakes, there is a prevalence of small-sized organisms of heterotrophic nutrition. There is a stable decreasing tendency of species composition of hydrobionts and simplification of food chains in urban aquatic ecosystems subject to anthropogenic impact.