The analysis of long-term data on the zooplankton of mesotrophic lakes of Belarus has been carried out in order to determine ways to assess the impact of climate change. The possibilities of using the parameters of zooplankton communities to register climate change are shown. It is indicated that changes in the density of psychrophilic species can be used to register the effects of increases in temperature.
The zooplankton of the floodplain reservoirs of the Middle Ob, located at various distances from the main channel of the river, has been studied. It is shown that, in floodplain reservoirs, the development of the summer zooplankton complex begins simultaneously with the passage of the flood; in the summer months, the greatest species diversity and the highest biomass are noted in them. The more often a reservoir is filled with high waters, the higher the species diversity and abundance of zooplankton in it. Factors have been identified that statistically significantly determine the development of zooplankton in floodplain reservoirs: frequency of flooding, water temperature, content of organic substances, and (for a number of taxa) gas regime. It is confirmed that the zooplankton of floodplain reservoirs differs significantly from the communities of the mother river and from the lakes of the terrace above the floodplain in significant faunal diversity, increased species richness, and specific species structure.
The results of summer studies of phyto- and zooplankton in aquatic systems of technogenic origin are presented. There are low species richness and a significant range of the quantitative indicators of aquatic organisms. The change in the main structure-forming taxa in the pH gradient is shown. Environmental factors that determine the composition and structure of plankton communities have been identified.
The long-term (2001–2020) data of the primary production and abundance of phytoplankton (according to the concentration of chlorophyll a) in the Vistula Lagoon under significant ecosystem changes have been analyzed. The long-term dynamics is characterized by an increase in primary production to a hypertrophic level (>450 g C/(m2 year) in 2006–2010. After the intensive development of the bivalve filter-feeding mollusk Rangia cuneata, the primary production in 2011–2020 remained at the hypertrophic level, despite significant changes in the structure and abundance of phytoplankton. Average annual primary production in 2001–2020 was 60% higher than in 1974–1976. Primary production exceeds the mineralization of organic matter in water by 60%, which leads to the secondary eutrophication of the Vistula Lagoon and pollution of the Baltic Sea.
The mass development of diatoms Dactyliosolen fragilissimus and Cerataulina pelagica, atypical algae for the southeastern Baltic Sea (SEB) water area, were registered along the Sambia peninsula coastline in the middle of October 2020. Both species were found in the coastal zone off the western and northern coast of the Sambia peninsula from the Baltic Strait to port Pionerskiy at depths reaching 32 m. In early November 2021, C. pelagica bloomed both in the shallow coastal zone of the northern coast of the Sambia peninsula and in the deepwater zone of the SEB. The biomass of this species reached 2.8 g/m3. Both diatom species were abundant within the entire Russian exclusive economic zone (EEZ). The prevailing hydrological situation during the study period probably facilitated the penetration of the species into the study area by surface transport from the Arkona Basin.
The species diversity and spatial distribution of ichthyoplankton in the shelf and deep-sea waters of the northern half of the Black Sea near the Crimean Peninsula and the shores of the Caucasus under the conditions of prolongation of the summer hydrological season 2020 for September–October are presented. The high temperatures of the upper layer of the sea, peculiar of the summer spawning season, cause a continuation of productive spawning of warm-water fish. Eggs and larvae of 19 species from 12 families are identified in the ichthyoplankton. The maximum number of eggs is 302 ind./m2 and that of larvae is 58 ind./m2. Eggs and larvae of the mass commercial species Engraulis encrasicolus (L., 1758) dominate, and their shares in the total population are 92.9 and 84.2%, respectively. The highest abundance of ichthyoplankton correspond to areas with minimal dynamic activity and maximum warming within the limits of coastal-shelf quasi-stationary anticyclonic vortices characteristic of the summer hydrological season.
General concepts of reservoirs as artificial water bodies with slow water exchange and a complex hydrodynamic structure are considered based on the published data. Reservoirs combine the features of a natural system powered by the sun and subsidized system and are characterized by highly dynamic development. Eight large plain reservoirs of the Volga cascade are characterized in detail. They extend from southern taiga to semidesert and differ in the morphometry, flow rate, and trophic status.
The intensity of oxidative processes and integral destruction of plankton in Volga reservoirs have been considered. Data on the seasonal dynamics and distribution of destruction in the water area of individual reservoirs and on the scale of the entire Volga cascade are provided. An assessment of the respiration losses of phytoplankton is given.
Freshwater bryozoans are unique invertebrates that have complicated life cycles and are sedentary, filter-feeding, colonial organisms. In scientific studies, freshwater bryozoans have gained very little attention. With just 88 species, this group of “moss animals” is spread out among ponds, lakes, streams, and rivers. They widely belong to the freshwater-only phylactolaemate class, while a few species can also be classified as members of the gymnolaemate class, which predominates in marine environments. In this study, we recorded two bryozoan species of Plumatella emarginata and P. geimermassardi for the first time in Valankulam Lake, Coimbatore City, Tamil Nadu, and they were identified and described based on their morphological characteristics.
Ecological data has a great importance for species distribution of whole aquatic systems. The aims of this study are determined to estimate the effects of various parameters (water temperature, dissolved oxygen, pH, electrical conductivity, salinity) on habitat preferences of Hydrophilidae and Helophoridae (Coleoptera) which were collected from Beyşehir Lake and surrounding areas in Konya province, Turkey. Principal Component Analysis (PCA) was used to determine which environmental factors are effective in the habitat preferences. According to the two first axes of the PCA analysis explained 59.5% of variation among sites in relation to their environmental features and pH, water temperature, electrical conductivity and salinity are the main water parameters associated with aquatic beetle distribution. Canonical correspondence analysis (CCA) revealed that the important physicochemical attributes of the species distribution were pH, electrical conductivity, and water temperature and CCA analyzes showed that the physicochemical parameters of water are directly related to the distribution of insects.
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