Структура зоопланктонних угруповань річкової ділянки літоралі Каховського водосховища - Статья

Запорізький національний університет СТРУКТУРА ЗООПЛАНКТОННИХ УГРУПОВАНЬ РІЧКОВОЇ ДІЛЯНКИ ЛІТОРАЛІ КАХОВСЬКОГО ВОДОСХОВИЩА Домбровський К.О., Бичок С.В. Проведено дослідження структурної організації зоопланктонних угруповань річкової ділянки літоралі Каховського водосховища в літній період. Встановлено видовий склад, представленість таксономічних груп, вивчено динаміку чисельності та біомаси зоопланктону упродовж 3-4 років дослідження. On the riverbed area of the Kakhovka reservoir in general 29 families, 55 genera and 83 species and forms of littoral zooplankton in the ratio of the major taxonomic groups Cladocera: Copepoda: Rotatoria (Cl: Co: Ro) as 24: 18: 41 were registered. In addition to the major taxonomic groups of zooplankton also tardigrades and ostracods were revealed. The greatest number of zooplankton species was identified in the overgrown areas of the upper reaches of the reservoir that are characterized by the dominance of various complexes of higher aquatic vegetation. So in the zooplankton community of the Balabinskii bay 41 species, including Rotatoria - 23 species (56%), Cladocera - 8 species (20%), Copepoda - 10 species (24%) were identified, and on the lake-like reach (city flows of waste treatment facilities) 35 species in the ratio of the major taxonomic groups Cl: Co: Ro as 12: 7: 16 were identified. 14 species of zooplankton, including Rotatoria - 6 species (43%), Cladocera and Copepoda - 4 species for each one (28, 5%), respectively were revealed above Zhdanovskii beach. 21 species, including 11 species of Rotatoria (52%), Cladocera - 8 species (38%), Copepoda - 2 species (10%) were identified in zooplankton below Zhdanovskii beach. In the area of the rest house «Volna» the zooplankton community was represented by 24 species in the ratio of the major taxonomic groups Cl: Co: Ro as 9: 9: 6. In 2014 in zooplankton community of the river area of the reservoir for the first time Rotatoria Lacinularia ismailoviensis was registered, which previously was not indicated in this reservoir. Also that year the representative of the Ponto-Caspian complex Cladocera Podonevadne camptonyx was revealed. During the period of study the stability of zooplankton community structure was no established: there was an annual change of the dominant species. In 1990 Bosmina longirostris, Keratella quadrata were the structure-forming species of zooplankton communities in most of the stations. According to the results of the research in 1997-1998 a complex of dominant species changed and was presented exclusively by Crustacea Scapholeberis mucronata, Chydorus sphaericus, Eudiaptomus vulgaris, Eucyclops serrulatus. In 2014 the structure-forming species and forms of zooplankton were mostly Rotatoria Trichocerca (s. Str.) Pusilla, K. cochlearis tecta, Colurella colurus and Copepoda Eud. vulgaris. The most common in this part of the reservoir during the whole period of study were Crustacea Sc. mucronata, Eud. vulgaris, Ch. sphaericus. The low indicators of average number and biomass of zooplankton were registered in 1990 which ranged between 565-1500 species/m2 and 3,9-31,4 mg/m2, respectively. The maximum values of the average number and biomass of zooplankton were identified in 1997-1998, which varied in the range of 140015200 species/m2 and 12,7-289,8 mg/m2, respectively. The river area of the Kakhovka reservoir corresponds to evtrophic type for the structural characteristics of zooplankton communities. The quality of water in this part of the reservoir corresponds to moderately polluted waters (P-mesosaprobic zone) for saprobity index during the whole period of study. Keywords: zooplankton, community structure, reservoir, trophic coefficient, saprobity index. Таблиця 2 Динаміка кількісних характеристик зоопланктону річкової ділянки Каховського водосховища вище Жданівського пляжу в літній період Рік Кількість видів Чисельність, екз./м3 Біомаса, мг/м3 Ro Co Cl Разом Ro Co Cl Разом Ro Co Cl Разом 1990 2 2 1 5 150 300 200 650 2,40 2,26 4,00 8,66 1997 4 1 2 7 1800 2100 4500 8400 1,14 8,40 135,6 145,14 1998 - 1 2 3 - 2100 600 2700 - 7,00 5,70 12,70 Примітка.