Inland Water Biology最新文献

Abstract

The article describes scientific and methodological possibilities of bioassays in the field of studying consequences of climate change for water bodies and aquatic organisms inhabiting them. Using fish aquacultures, it was found that an increase in water temperature changes biochemical parameters of internal environments of organisms, affects their behavior and the number of offspring. A number of biogeochemical transformations of aquatic ecosystems are predicted: a decrease in water pH, mineralization of organic matter in bottom sediments, release and increase in bioavailability of compounds of potentially toxic elements. Using bioassay methods on monocultures and laboratory microcosms, it was shown that pessimal temperature values and a cascade of accompanying changes will lead to a restructuring of the community of aquatic organisms, changes in the habitats of organisms, and the disappearance of stenothermic species. The reality of such scenarios is confirmed by paleodata and phenomena that are already happening.

Abstract

According to data on the late 20th century in the Trans-Baikal and Baikal areas, the family Najadaceae is represented by four species known in few localities: Caulinia flexilis (4 localities), C. minor (3), Najas major (3), and N. marina (4). All of them are annuals, r-strategists, which are characterized by fluctuations in abundance. Since the 21st century, these species have been found in 20 more localities, mainly situated within the Baikal Depression. In 2015, when performing monitoring studies of aquatic flora, three more new localities of Caulinia flexilis, C. minor, and Najas major were found in the basin of the Amur River. Distribution maps of the Najadaceae species in the region were compiled, and the ecological characteristics of their habitats were given. In Trans-Baikal area, since the middle of the 20th century, warming has occurred due to an increase in the average annual temperature. For the last 70 years, aridization has increased in southern regions, which changes the habitat conditions in waterbodies. Findings of these Najadaceae species in Trans-Baikal area have coincided with the periods of increase in mean annual air temperatures and with local minimums of precipitation. An increase in the number of findings of Najadaceae species since the beginning of the 21st century, both in the Trans-Baikal area and in other regions of Russia, has been occurring against the background of an increase in the average annual air temperature. In Trans-Baikal area, the trend of increasing of temperatures in the warm season since the beginning of the 21st century is favorable for these species and may contribute to their further distribution.

Abstract

Studies of the pollution of Lake Baikal with microplastic particles have been started quite recently. Almost all of them are focused on assessing surface water pollution, while the impact of microplastics on Baikal organisms remains unexplored. We have conducted a laboratory experiment involving three species of gastropod mollusks, the Palearctic Lymnaea stagnalis (L., 1758) and Radix auricularia (L., 1758) and the Baikal endemic Benedictia baicalensis (Gerstfeldt, 1859). Two types of microplastics are used in the experiment: fragments of polystyrene and polyester fibers prepared in the laboratory. These plastic particles, along with the food mixture, are placed in aquariums with mollusks. In total, 386 preparations with mollusk excrements have been obtained (144 preparations from Radix auricularia, 176 from Lymnaea stagnalis, and 67 from Benedictia baicalensis). The experiment with Benedictia baicalensis has been carried out only with polystyrene fragments. All preparations have been analyzed according their fluorescence ability. The data have been statistically processed using Spearman’s rank correlation coefficient. The data allow us to conclude that gastropods of these species are able both to absorb microplastic particles and remove them from the body. However, the rate of removal of microplastic particles from the body of a mollusk is species-specific and also directly depends on the morphological structure of microplastic particles.

Abstract

The features of the structure of zooplankton in beaver ponds and the course of successions in zooplanktocenoses have been studied in the Kologrivsky Forest State Natural Reserve. Ponds are divided into groups according to the nature of the watercourse on which they are formed, the height of the floodplain, and the duration of existence. The seasonal succession of zooplankton for all types of ponds begins with the predominance of juvenile stages of Copepoda. In the summer, in newly formed ponds and in ponds on rivers with high floodplains, a typical zoogenic transformation of communities is observed that occurs with the development of large Cladocera. In long-term ponds on streams and in rivers with low floodplains, the dominance of Rotifera and small Cladocera (which are characteristic of anthropogenic eutrophication) and the highest average values of abundance and biomass, indices of species diversity, and evenness are noted.

Abstract

The results of the ecological and anatomical study of plants in the coastal shallows of rivers and lakes of the Lower Amur region are presented to identify their resistance and adaptability to the habitat conditions. Seven stenotopic species have been studied. It is revealed that the vegetative organs of plants are characterized by a combination of typical hydromorphic and specific adaptive features. The species are adapted to sandy-clay shallow habitats due to histological transformations of the main tissues. The narrow specialization of species does not affect the typical structure of plant organs and does not cause a simplification of their internal structure. The studied species are to a greater extent characterized by evidences of terrestrial micromorphology (sclerification, suberinization, and cutinization of tissues) rather than of hydrophytic one. It is assumed that a specific complex of flora of shallows is mainly formed by terrestrial species.

Abstract

In populations of different systematic groups of fish living in lakes of both the same and different continents, the patterns of morphological differences between piscivorous and non-piscivorous ecological forms under sympatric conditions were analyzed. It is shown that, in the Altai osmans of the species Oreoleuciscus potanini in two lakes of the Central Asian Closed Basin, the pattern of differences is almost identical to the pattern of differences between the piscivorous and non-piscivorous forms of barbs of the Barbus intermedius complex sensu Banister (1973) in the African Lake Tana. At the same time, the pattern of differences between the piscivorous and non-piscivorous forms of another species of Altai osmans, Oreoleuciscus humilis, in the lake located in another part of the Central Asian Closed Basin differs significantly from the pattern of differences in ecological forms of both the species O. potanini and the B. intermedius complex. It is assumed that the following explanation may be given for the revealed difference in the variability of osmans in the studied water bodies. In the African Lake Tana and Mongolian lakes Bayan and Khar-Us, the pattern of differences reflects the long-standing situation of stationary coexistence of piscivorous and non-piscivorous forms in the same water body. The pattern of variability in the periodically drying Mongolian Lake Orog reflects not a stable situation, but an incomplete process of its developing interrupted over and over again by the death of the lake population during the next drought period.

Background: There are no studies currently in the literature that assesses complications following revision total shoulder arthroplasty (TSA) in patients with varying severity of anemia. The purpose of this study was to determine the impact of preoperative anemia severity on postoperative complications following revision TSA.

Methods: Patients undergoing revision TSA from 2013 to 2019 were queried in a national database. Based on previous studies' definitions of anemia, three subgroups were stratified: patients without anemia (hematocrit >36% for women, hematocrit >39% for men), patients with mild anemia (hematocrit 33% to 36% for women, hematocrit 33% to 39% for men) and patients with moderate to severe anemia (hematocrit <33% for both women and men). In this analysis, patient demographics, comorbidities, and postoperative complications were compared between the three groups.

Results: Of 1559 total patients undergoing revision TSA, 1178 patients (75.6%) did not have anemia, 255 (16.3%) had mild anemia, and 126 (8.1%) had moderate/severe anemia. Following adjustment on multivariate analysis, patients with mild anemia were more likely to have postoperative transfusion and extended length of stay compared to non-anemic patients. Patients with moderate/severe anemia were at increased risk of postoperative transfusion, sepsis, extended length of stay, and reoperation compared to non-anemic patients.

Discussion: From mild anemia to moderate/severe anemia, there was a stepwise increase in the risk of postoperative complications. Our study showed that there is clinical value in the preoperative correction of anemia for these patients as it relates to complications and hospital stay.

Level of evidence: III.

Abstract

In 2019, due to changes in the hydrograph caused by the construction of dams upstream, the Mekong River Basin experienced a decline in delta water level. In this year, macrozoobenthos communities of the Bassac (Hau) and Mekong (Tien) Rivers in Vietnam were studied in April and December. The total species richness, abundance, and biomass of studied macrozoobenthos assemblages did not depend on any environmental factors. The β-diversity estimation for species abundance shows the existence of three groups of species assemblages, related mostly to salinity. Most assemblages were characterized by low species richness (3.2 on average) and similarity (general mean Bray-Curtis = 8%), a large number of species, which were dominants in certain assemblages (31–42% of the total list), with the absence of a relationship with hydrological zones or seasons. This allowed us to consider these groupings as “pseudocommunities”, randomly formed in the extreme conditions of a sharp change in the hydrological regime of the Mekong River Delta in 2019.

Abstract

The results of an analysis of the morphophysiological and biochemical indicators of somatic growth in Black Sea bivalve mollusks, the cockle Cerastoderma glaucum (Bruguiere, 1789) and the scallop Flexopecten glaber ponticus (Bucguoy, Dautzenberg et Dollfus, 1889), living in the vicinity of Sevastopol, are presented. The examples are of three size-age groups in the length range from 12 to 30 mm for both species; the features of tissue biosynthesis (somatic growth) of soft tissues are studied. According to the total RNA content and the RNA/DNA index in the C. glaucum, it is shown that, in the 17–22 and 23–28 mm groups (age 2–3 years), the level of synthesis of protein structures is 1.3–1.7 times higher than in the underyearlings. In individuals of F. glaber ponticus with linear sizes of 13–17 and 21–24 mm (underyearlings), the level of synthesis of protein structures is 1.2–1.5 times higher than in larger individuals (age 2 years). The species specificity of somatic growth is most significantly manifested in the middle and older size groups of the studied mollusks. The values of biochemical growth parameters in both species indicates an average level of tissue growth in comparison with other previously obtained data for the mass Black Sea bivalves. Linear regression models of size–weight values show that, for both species, the change in size explains 62–86% of the variation in body weight of the mollusk. An analysis of weight parameters (total mass/soft tissue mass) indicates a positive allometry of somatic tissue growth.

Abstract

The results of a complex hydrochemical and hydrobiological study of salt lakes in southeastern Transbaikalia during the period of moisture change are presented. The studied lakes, according to geochemical classification, are chloride and soda types. The taxonomic diversity of aquatic biota decreases, while the salinity increases and the hydrochemical type of lakes changes from soda oligo-mesohaline (4–16 g/L) to chloride eu-hyperhaline (33–70 g/L) and soda hyperhaline (128–231 g/L). In soda oligo-mesohaline and chloride lakes, the phytoplankton taxonomic composition is similar and is represented by green and diatom algae, as well as cyanobacteria. Submerged aquatic plants are represented by Stuckenia pectinata in soda oligo-mesohaline lakes. Ruppia maritima is found in the Dabasa-Nor chloride lake. In zooplankton and zoobenthos, rotifers and chironomids dominate respectively. Quantitative characteristics of phytoplankton in oligo-mesohaline lakes are lower than in hyperhaline soda and eu-hyperhaline chloride lakes. The phytomass of submerged aquatic plants, on the contrary, is higher in oligo-mesohaline lakes. In the hyperhaline soda lake Borzinskoye, zoobenthos and zooplankton organisms are represented by planktonobenthos species, namely Anostraca, with low abundance.