Preliminary Assessment of Ecological Status of the Siversky Donets River Basin (Ukraine) Based on Phytoplankton Parameters and Its Verification by Other Biological Data
Abstract:The river basin of Siversky Donets is of great scientific interest since this river runs through a territory with heavy industry (in particular, coal mining, chemical processing and metal industries). Within the basin, rivers of different sizes were explored (small, medium, large and extra-large) that flow through siliceous and calcareous rocks on the same elevation (lowland—below 200 m a.s.l.). Phytoplankton, as one of the Biological Quality Element, was used to perform the assessment of ecological status of … Show more
“…One of the ways of implementing the purposes of this document is assessment of ecological condition and risks that could hinder its improvement (Solimini et al, 2008;Allan, 2012). Measures of the Water Framework Directive of the EU have already been introduced for many aquatic objects of Europe: rivers (Spänhoff et al, 2012;Bilous et al, 2021;Skoulikidis et al, 2021), lakes (Søndergaard et al, 2005;Latinopoulos et al, 2021;Ntislidou et al, 2021), transitional (Pérez-Ruzafa et al, 2007;Cacciatore et al, 2019;Facca, 2020) and coastal (Giovanardi et al, 2018;Gerakaris et al, 2022) water, including river deltas (Newton et al, 2014;Stoica et al, 2014;Goulding et al, 2021).…”
Resumption of shipping in the Bystryi branch in the Ukrainian part of the Danube Delta, one of the largest aquatic-wetland areas of Europe and the world, has made it necessary to control the anthropogenic impact on the neighboring water areas of the Danube Biosphere Reserve. The objective of the study was comparing the compositions and structure of phytoplankton, microphytobenthos, macrophytes, benthic invertebrates and ichthyofauna of the mouth area of the Bystryi branch with such communities of the mouths of the branches Vostochnyi, Tsyhanka and Starostambulskyi, which are situated in the protected zone and characterized by limited anthropogenic activity. We also determined the correspondence of the descriptors of biotic groups to the categories of the ecological status according to the Water Framework Directive of the EU. The studies were performed in the autumn and summer periods in 2020–2021. We recorded 367 species of animals and plants, the richest biodiversity was seen for the biota of the Bystryi branch – 250 species, and 180–231 species of hydrobionts were found in the undisturbed mouths. We determined 25.3% of shared species for the water areas, and therefore high values of similarity of the species compositions according to Bray-Curtis (47.5% to 81.5%). We determined no significant differences between the groups of the mouths of the examined branches according to most indicators of taxonomic and ecological structure. As the descriptors of ecological status, we chose assemblage indices of phytoplankton and microphytobenthos, which are based on ratios of biomass of functional groups of algae, and also the Macrophyte Biological Index for Rivers, saprobic index of Zelinka & Marvan and Biological Monitoring Working Party Index of Benthic Invertebrates and Representation of Species of Ichthyfauna according to vulnerability to actions of environmental factors. We determined that the range of descriptors of phytoplankton and microphytobenthos corresponded to the “high” ecological status category, such of macrophytes and benthic invertebrates to “good”, and such of ichthyofauna varied “high” to “good”. In general, all the mouth areas were characterized by “good” ecological status. Similarities of the species composition and the structure of biotic communities of the mouths of the studied branches of the delta indicate the absence of negative impact of the deepwater shipping on adjacent ecosystems, which may be related to the peculiarities of reactions of groups in the water areas with natural stress, as well as local impact of the hydrotechnical construction.
“…One of the ways of implementing the purposes of this document is assessment of ecological condition and risks that could hinder its improvement (Solimini et al, 2008;Allan, 2012). Measures of the Water Framework Directive of the EU have already been introduced for many aquatic objects of Europe: rivers (Spänhoff et al, 2012;Bilous et al, 2021;Skoulikidis et al, 2021), lakes (Søndergaard et al, 2005;Latinopoulos et al, 2021;Ntislidou et al, 2021), transitional (Pérez-Ruzafa et al, 2007;Cacciatore et al, 2019;Facca, 2020) and coastal (Giovanardi et al, 2018;Gerakaris et al, 2022) water, including river deltas (Newton et al, 2014;Stoica et al, 2014;Goulding et al, 2021).…”
Resumption of shipping in the Bystryi branch in the Ukrainian part of the Danube Delta, one of the largest aquatic-wetland areas of Europe and the world, has made it necessary to control the anthropogenic impact on the neighboring water areas of the Danube Biosphere Reserve. The objective of the study was comparing the compositions and structure of phytoplankton, microphytobenthos, macrophytes, benthic invertebrates and ichthyofauna of the mouth area of the Bystryi branch with such communities of the mouths of the branches Vostochnyi, Tsyhanka and Starostambulskyi, which are situated in the protected zone and characterized by limited anthropogenic activity. We also determined the correspondence of the descriptors of biotic groups to the categories of the ecological status according to the Water Framework Directive of the EU. The studies were performed in the autumn and summer periods in 2020–2021. We recorded 367 species of animals and plants, the richest biodiversity was seen for the biota of the Bystryi branch – 250 species, and 180–231 species of hydrobionts were found in the undisturbed mouths. We determined 25.3% of shared species for the water areas, and therefore high values of similarity of the species compositions according to Bray-Curtis (47.5% to 81.5%). We determined no significant differences between the groups of the mouths of the examined branches according to most indicators of taxonomic and ecological structure. As the descriptors of ecological status, we chose assemblage indices of phytoplankton and microphytobenthos, which are based on ratios of biomass of functional groups of algae, and also the Macrophyte Biological Index for Rivers, saprobic index of Zelinka & Marvan and Biological Monitoring Working Party Index of Benthic Invertebrates and Representation of Species of Ichthyfauna according to vulnerability to actions of environmental factors. We determined that the range of descriptors of phytoplankton and microphytobenthos corresponded to the “high” ecological status category, such of macrophytes and benthic invertebrates to “good”, and such of ichthyofauna varied “high” to “good”. In general, all the mouth areas were characterized by “good” ecological status. Similarities of the species composition and the structure of biotic communities of the mouths of the studied branches of the delta indicate the absence of negative impact of the deepwater shipping on adjacent ecosystems, which may be related to the peculiarities of reactions of groups in the water areas with natural stress, as well as local impact of the hydrotechnical construction.
“…To determine the environmental factors affecting the diversity of phytoplankton in the Sasyk, a few studies were performed. Bioindicator analyses were performed according to [22], based on species-specific ecological preferences of the revealed algae and cyanobacteria [23][24][25], with the combination of species with similar ecological properties to indicator groups reflecting the response of aquatic ecosystems to habitat, pH, oxygenation, water mass dynamics, salinity, trophic state, and the class of organic pollution. The analysis of bioindicators included several steps.…”
Section: Bioindicators and Statistical Analysismentioning
Forty years ago, the transformation of the estuary of the Black Sea to a freshwater reservoir was started by its connection with the Danube River through the Danube–Sasyk Canal. Today, the inflow of the Danube water into the Sasyk is the main component of the water balance, affecting the internal and external water exchange, and it is, in general, responsible for the quality of the aquatic environment. In addition, the channel is a migration route for hydrobionts and the main source of invasion. We describe the changes in the composition of algal communities in Sasyk, which was converted from an estuary to a reservoir during three stages: estuary-lake in 1967–1977 (stage I), the forming of the reservoir from 1980–1990 (stage II), and the reservoir from 2013–2019 (stage III). Average salinity decreased from 7790 to 491 mg L−1 chlorides, and the species richness of algae increased from 259 to 289 taxa during the Sasyk transformation. Analysis of the algal communities revealed that salinity could have an effect on their composition. The species list for the Sasyk, including 586 taxa of algae and cyanobacteria (613 infraspecific taxa), is presented here for the first time. Rare marine and freshwater taxa present in the algal community at the modern stage of the reservoir and their transformation are discussed. An ecological analysis of the different stages of the Sasyk transformation from an estuary into a reservoir was conducted. The increase in species richness for stages II and III along with an increase in desalination was noted. To keep the current ecological status of the reservoir and its hydrological stability, the role of the Danube River should be considered. Bioindicators, statistical analysis of species, and environmental variables’ relationships confirm salinity as a major regulating factor that can be observed by way of long-term monitoring.
“…In fact, practically the entire basin of the Siverskyi Donets River and rivers of the northern coast of the Sea of Azov are affected by the mine waters. The environmental effects can be assessed only after the hostilities’ cessation by comparison of data with those obtained before the wide-scale Russian aggression [ 244 ].…”
This paper is a synthetic overview of some of the threats, risks, and integrated water management elements in freshwater ecosystems. The paper provides some discussion of human needs and water conservation issues related to freshwater systems: (1) introduction and background; (2) water basics and natural cycles; (3) freshwater roles in human cultures and civilizations; (4) water as a biosphere cornerstone; (5) climate as a hydrospheric ‘game changer’ from the perspective of freshwater; (6) human-induced stressors’ effects on freshwater ecosystem changes (pollution, habitat fragmentation, etc.); (7) freshwater ecosystems’ biological resources in the context of unsustainable exploitation/overexploitation; (8) invasive species, parasites, and diseases in freshwater systems; (9) freshwater ecosystems’ vegetation; (10) the relationship between human warfare and water. All of these issues and more create an extremely complex matrix of stressors that plays a driving role in changing freshwater ecosystems both qualitatively and quantitatively, as well as their capacity to offer sustainable products and services to human societies. Only internationally integrated policies, strategies, assessment, monitoring, management, protection, and conservation initiatives can diminish and hopefully stop the long-term deterioration of Earth’s freshwater resources and their associated secondary resources.
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