T. D. Zinchenko

Comprehensive ecological zoning of the Kuibyshev Reservoir

Multidimensional mathematical analysis of a set of abiotic and biotic indices was carried out on the basis of many-year (1958–1984, 1992) observations of the Kuibyshev Reservoir. The character of the space and time dynamics of the samples is studied; the localization of sections of statistically homogeneous data was implemented. Graphs of the long-term spatial taxonomic structure of water masses were analyzed for different periods. The graphs had been formed with the use of the principal component method, neuron network modeling, and self-organizing Kohonen maps. Comprehensive zoning of the reservoir water area was carried out with the help of GIS technologies.

Comparison of fatty acid compositions in birds feeding in aquatic and terrestrial ecosystems

Fatty acid (FA) contents and compositions in the pectoral muscles of 18 bird species from Novosibirsk, Volgograd, and Yaroslavl oblasts were studied. Three groups of birds that had significantly different FA compositions were distinguished based on a multivariate statistical analysis: Passeriformes, Columbiformes, and a group of waterfowl and waterbird species (Charadriiformes, Anseriformes, Podicipediformes, and Ciconiiformes). The highest content of physiologically important docosahexaenoic acid (22:6n-3, DHA), which is considered a marker of aquatic food, was surprisingly found in the biomass of Passeriformes, which are terrestrial feeders, rather than in the biomass of waterfowls and waterbirds. It was suggested that Passeriformes species had the ability to synthesize large quantities of DHA from short-chain omega-3 FAs, which is rare among animals.

Macrozoobenthos in saline rivers in the Lake Elton basin: Spatial and temporal dynamics

The data on seasonal and interannual changes in the taxonomic, structural, and quantitative characteristics of macrozoobenthos communities in rivers with a high salinity gradient are given. A total of 91 benthic invertebrate taxa have been revealed, which were dominated by Cricotopus salinophilus, Chironomus salinarius, C. aprilinus, Tanytarsus kharaensis, Microchironomus deribae, Glyptotendipes salinus (Diptera: Chironomidae), Culicoides (M.) riethi, Palpomyia schmidti (Diptera: Ceratopogonidae), Paranais simplex (Oligochaeta), and Ephydra sp. (Ephydridae) in different years. The fauna of benthic communities is mainly represented by eurybiontic halotolerant species with different ranges of resistance to salinity. The taxonomic composition and diversity of macrozoobenthos communities are closely correlated with water salinity in the range from 4 to 41 g/L; the complex of hydrological and hydrophysical factors (depth, overgrowing, water temperature, pH, etc.) control the distribution and abundance of species.

All stages of the Palaearctic predaceous midge Palpomyia schmidti Goetghebuer, 1934 (Diptera: Ceratopogonidae)

All stages and the ecology of the Southern Palaearctic Palpomyia schmidti collected from the vicinity of the saline Lake Elton in Russia are described and illustrated. The morphology of larvae and pupae as well as the detailed ecology of the larvae are described for the first time. P. schmidti is a halobiontic biting midge, widely distributed in the steppes and deserts of the Palaearctic region. It is proposed that the Palpomyia schmidti group should include five Holarctic species. P. downesi Grogan & Wirth, 1979 from north-western North America is recognized as a new junior synonym of the Eastern Palaearctic P. tuvae Remm, 1972. New synonymy.

Redescription of larva, pupa and imago male of Chironomus (Chironomus) salinarius Kieffer from the saline rivers of the Lake Elton basin (Russia), its karyotype and ecology

Cytology and ecology of Chironomus (Chironomus) salinarius Kieffer, 1915 (Diptera, Chironomidae) was examined from material collected in the saline rivers of the Lake Elton basin (Volgograd region, Russia). Larvae of salinarius-type were identified as C. salinarius on the basis of their karyotype. The species is redescribed on the basis of all metamorphic stages. The reared imago and karyotype were obtained from larvae of the same population. The karyotype of C. salinarius, detailed mapping of the 5 chromosome arms A, C, D, E, F and characteristics of chromosome polymorphism are provided. Information on distribution and ecology of C. salinarius from the saline rivers (total mineralization 6.8-31.6 g l-1) of the Lake Elton basin is also given. Chironomus salinarius is a common in the saline rivers and occurs in sediments with high silt content. On the basis of recent samplings C. salinarius appears to be very abundant in saline, mesotrophic as well as in eutrophic rivers. Chironomus salinarius accounted for 49-66% of total abundance of zoobenthos in water with salinity up to 13-31.6 g l-1.

Biological aspects of the associations of biting midges (Diptera: Ceratopogonidae) in two saline rivers of the Elton Lake Basin, Russia

We studied species composition, density, biomass and production of larvae of the family Ceratopogonidae in two saline rivers (Volgograd region, Russia). Ceratopoponids make up an important part of macroinvertebrate community in these rivers. Average monthly production (dry weight) of ceratopogonid larvae in the rivers was 3.5–4.8gm–2 month–1 in May and ~0.9gm–2 month–1 in August. For the first time, feeding spectra of ceratopogonid larvae, Palpomyia schmidti Goetghebuer, 1934, was studied using fatty acid analyses. The larvae of P. schmidti appeared to selectively consume diatoms and other algae and to avoid bacteria and decomposed dead organic matter (detritus) of low nutritive quality.

Plankton and Bottom Communities in the Saline Rivers of Lake Elton Basin: Statistical Analysis of Dependences

Hydrological, hydrochemical, and hydrobiological data for five saline rivers of the arid Lake Elton region were analyzed. We found that interactions between plankton and benthic communities, in particular, between macrozoobenthos, meiobenthos and zooplankton, created mixed ecological groups of species. Abundances of plankton and bottom communities significantly correlated, which indicated that there is a close relationship between them due to biotic interactions and their similar responses to the effects of environmental factors. Multidimensional scaling and cluster analyses, the construction of hierarchical trees and species diversity models, the spatial correlation Mantel test, etc., were used to study the structure of communities in strongly disbalanced ecosystems of highly mineralized rivers. Indicator species were established by the TWINSPAN procedure. Our results demonstrated that plankton and bottom communities of the saline rivers can be represented as specific consortia or structural units of the river ecosystems.

Statistical Analysis of Structural Variations of Benthic Communities and Testing the Hypothesis of River Continuum

Statistical methods for assessing the spatial distribution of benthic communities in different parts of watercourses have been considered as applied to lowland rivers of the Lower Volga region. The applicability domains are described for different response models, gradient analysis, and random skewers methods, which are used to analyze the distribution of aquatic organisms in bottom sediments. Stationarity and autocorrelation criteria for the description of generalized characteristics of macrozoobenthos communities are analyzed. The problems of identification of statistically significant isolated zones at whose boundaries the succession change of the species composition of aquatic organisms are discussed. The results of nonparametric dispersion analysis of species similarity matrices, the formation of dendrites, and the search for barriers between individual areas are given (based on Delaunay triangulation and Monmonier’s maximal-diversity algorithm).

An indicative assessment of macrozoobenthos organisms in flowing waters

Indicator valences, taking into account the regional features of the middle and lower Volga River basin of water quality classes for the benthofauna of lowland rivers, are calculated. The lists of 450 species that can be used to indicate pollution are given. An advanced method of estimating bioindication factors of bottom organisms is used. The results of calculations can be used for the quality intercalibration of the surface water of lotic systems.