Архив метки: zooplankton

THE INFLUENCE OF THE IONIC COMPOSITION OF WATER ON THE STRUCTURE OF THE ZOOPLANKTON OF THE LAKES OF THE TAZHERAN STEPPE (WESTERN BAIKAL REGION)

Arid Ecosystems

Yermolaeva N.I.,  Fetter G.V. THE INFLUENCE OF THE IONIC COMPOSITION OF WATER ON THE STRUCTURE OF THE ZOOPLANKTON OF THE LAKES OF THE TAZHERAN STEPPE (WESTERN BAIKAL REGION) // Arid ecosystems. 2021. V.27. № 4 (88). P. 107-117. | PDF

An assessment of the modern state of the zooplankton of diverse lakes of the Tazheran steppe and the identification of the features of the formation of the structure of communities depending on the change in the ionic composition of water under the influence of changing hydrophysical conditions was carried out. In August 2017, hydrochemical indicators and zooplankton of 6 lakes were investigated: Namshi-Nur, Holbo-Nur, Gyzgi-Nur, Nuhu-Nur, nameless and Hara-Nur. It has been shown that when lakes dry and salinity increases, a decrease in the species diversity of zooplankton is noted. The main factors explaining 77.9% of the dispersion of numerical indicators of certain types of zooplankton in the lakes of the Tazheran steppe were salinity, the depth of the lakes, primary production, the content of organic substances, and the amount of dissolved oxygen. Different types of zooplankton respond to changes in each individual factor in different ways. When assessing the effect of a particular factor on zooplankton, it is necessary to take into account the limits of tolerance of individual species to the effects of each factor individually and to their combination.

Keywords: salt lakes, zooplankton, hydrochemical conditions, environmental factors, ecological optimums, Baikal region.

Financing. The work was carried out within the framework of the Project 134.1.2. of the program of the Federal Research Institute of State Academies «Spatial and temporal organization of aquatic ecosystems and assessment of the influence of natural and anthropogenic factors on the formation of hydrobiocenoses and the quality of surface waters».

DOI: 10.24412/1993-3916-2021-4-107-117

HYDROBIOLOGICAL RESEARCH OF THE TEREK-CASPIAN COASTAL AREA

Arid Ecosystems

Osmanov M.M., Amaeva F.Sh., Abdurakhmanova A.A. HYDROBIOLOGICAL RESEARCH OF THE TEREK-CASPIAN COASTAL AREA // Arid ecosystems. 2021. V. 27. № 2 (87). P. 106-111 | PDF

Structure of zooplankton communities in the Terek-Caspian coastal region of the Caspian Sea under the conditions of flow regulation of the river Terek and its passage through the Uch-Kosinsky channel are researched. Hydrobiological material collected in the waters of the Terek coastal region of the Caspian sea was used. The long-term data of zooplankton distribution in the studied region, which reflect the nature of the influence of various factors, as fluctuations in the level regime, arid climate, the mass development of the Azov-Blacksea invader Acartia tonsa (Dana, 1849) and the trophic press of another invasive species Mnemiopsis leidyi (A. Agassiz) after passing the river runoff Terek in a new direction. The influence of these factors mainly affected the autochthonous fauna of the waters of the Terek coast. It was shown that previously leading native species Calanipeda aquae dulcis and Eurytemora grimmi for a long period were in the background and only in recent years C. a. dulcis, due to a decrease in the press of the ctenophore Mnemiopsis leidyi, becomes a subdominant form in the zooplankton of the studied water area of the Caspian Sea.

Keywords: The Caspian Sea, Uch-Kosinskiy channel, arid climate, zooplankton, species diversity, Copepoda, invasive species.

DOI: 10.24411/1993-3916-2021-10156

CURRENT STATE AND LONG-TERM DYNAMICS OF ZOOPLANKTON OF THE TSIMLYANSK RESERVOIR (DON RIVER, RUSSIA)

Arid Ecosystems

Lazareva V.I. CURRENT STATE AND LONG-TERM DYNAMICS OF ZOOPLANKTON OF THE TSIMLYANSK RESERVOIR (DON RIVER, RUSSIA) // Arid ecosystems. 2021. V. 27. № 2 (87). P. 112-119 | PDF

The structure and distribution of zooplankton of the Tsimlyansk Reservoir was studied in August – September 2018. It was shown that the amount of zooplankton was halved from the Upper part of the reservoir (2.4 ± 0.8 g / m3) to the dam of the Tsimlyanskaya hydroelectric station (1.2 ± 0.6 g / m3), Copepoda formed 70% of the biomass. Ponto-Caspian Heterocope caspia and invaders Calanipeda aquaedulcis, Thermocyclops taihokuensis and Acanthocyclops americanus were abundant copepod species. According to literature data, the dynamics of the zooplankton abundance in the reservoir for more than 65 years of its existence (1952–2018) is analyzed. A more than double (up to 2.1 ± 0.5 g / m3) biomass of the community was revealed in 2015–2018 compared with the 40-year period until 2013 (0.8 ± 0.1 g / m3). The trends in the dynamics of the zooplankton abundance in the Tsimlyansk reservoir are discussed, including the importance of the Ponto-Caspian crustaceans and invaders from other regions in the community.

Keywords: Don River, Tsimlyansk reservoir, zooplankton, invaders, structure, abundance, long-term dynamics.

DOI: 10.24411/1993-3916-2021-10157

ANALYSIS OF THE META-COMMUNITY STRUCTURE OF PLANKTON AND BOTTOM ORGANISMS IN RIVERS OF THE LAKE ELTON BASIN

Arid Ecosystems

Zinchenko T.D.,  Shitikov V.K.,  Golovatyuk L.V., Abrosimova E.V. ANALYSIS OF THE META-COMMUNITY STRUCTURE OF PLANKTON AND BOTTOM ORGANISMS IN RIVERS OF THE LAKE ELTON BASIN // Arid ecosystems. 2020. V. 26. № 4 (85). P. 150-156. | PDF

The authors performed a statistical analysis of hydrochemical and hydrobiological data obtained during the sampling of macrozoobenthos, meiobenthos and zooplankton in 2013, 2018 on different biotopes of five highly mineralized rivers of the basin of the hyperhaline Lake Elton. The authors consider the general patterns of the species structure of the meta-community of aquatic organisms based on the concept of Leybold and Mikkelson (Leybold, Mikkelson, 2002). Using random null-models the authors tested the hypothesis of consistent species occurrence (coherence), the formation of compact species associations (boundary clumping), and the regular change in the species composition along ecological gradients (turnover). The authors found the unsteady and intermittent nature of changes in biotic diversity, as well as the high mosaic taxonomic structure, that is typical for stochastic-type ecosystems.

The authors established a close correlation within individual mixed associations of benthic and plankton species. This relationship is due to biotic interactions and the coordinated response of organisms to environmental factors. Using statistical models of the “random forest” and subsequent multivariate analysis, the authors identified groups of species according to their degree of tolerance to external abiotic influences and determined the complexes of factors that have a significant impact.

Keywords: saline rivers, zooplankton, macrozoobenthos, meiobenthos, metacommunity structure, indicator species, partial correlation network, factor analysis.

DOI: 10.24411/1993-3916-2020-10130