The Role of Planktonic Algae in the Ecological Assessment of Storage-Reservoirs of the ILI-Balkhash Basin

Algae and Cyanobacteria Diversity and Bioindication of Long-Term Changes in the Hula Nature Reserve, Israel

Lake Hula, the core of one of the most extensive wetland complexes in the Eastern Mediterranean, was drained in 1951–1958. However, about 350 hectares of papyrus marshes were allocated in the southwestern part of the previous lake and became the Hula Nature Reserve status, the first of two wetlands in Israel included in the Ramsar List of Wetlands of International Importance. The list of algae and cyanobacteria species of Lake Hula was compiled by us for the first time based on data from publications of 1938–1958, as well as our research in the Hula Nature Reserve, obtained within the framework of the monitoring program for 2007–2013. The list includes 225 species and intraspecies of algae and cyanobacteria belonging to eight phyla. The dynamics of the species richness of algae and cyanobacteria flora for 1938–2013 are shown. Species-bioindicators of water quality have been identified, and the change in their composition by ecological groups for a period of about a hundred years has been shown. Based on the species richness of algae communities, water quality indices were calculated with particular attention to changes in trophic status during the study period. The algae flora of Lake Hula and Hula Nature Reserve was found to be similar, but bioindication has revealed an increase in salinity and organic pollution in recent years.

Species and Thallus Structure Diversity of Chlorophyta in Shore Platform of Dwarka (Gujarat Coast, India)

Present study shows the species and thallus structure diversity of Chlorophyta in shore platform of Dwarka, Gujarat Coast. Chlorophyta were surveyed based on systematic random sampling for two years: April 2013 to April 2015. Total 27 species of Chlorophyta were identified through intensive fieldwork survey based on line transect and quadrate based methods. This study identifies four orders, nine families, 13 genera and 27 species among the green macroalgae population inhabiting the rock shore platform of Dwarka. Total 27 species of Chlorophyta have been found with major nine thallus types and 19 sub types of thallus structure. Ramiform and filamentous types of thallus structure are most common in this study.

Planktonic Invertebrates in the Assessment of Long-Term Change in Water Quality of the Sorbulak Wastewater Disposal System (Kazakhstan)

The multicomponent composition of wastewater makes it challenging to assess its quality objectively, but the last one is a prerequisite for the safe re-use of wastewater. The solution to this problem should be aimed at finding criteria that make it possible to increase the objectivity of assessing the water quality of reservoirs with multicomponent pollution. This work analyzes the water quality of the Sorbulak wastewater disposal system in the summer of 2017, based on chemical variables and zooplankton structure and assess the long-term changes in the water quality of Sorbulak. According to the Kruskal–Wallis test, in 2017, the differences between the studied water bodies in the content of nutrients and heavy metals were mostly insignificant. From 2000–2002 to 2017, nitrate, nitrite nitrogen, and heavy metals in Sorbulak significantly decreased. Zooplankton communities consisted of a relatively small number of eurybiontic species resistant to environmental factors. The variability of the quantitative variables of zooplankton was associated with the nutrients. Males dominated the population of the cyclopoid copepods Acanthocyclops trajani. In 2000–2002 individuals with morphological anomalies were found in cyclopoid copepods populations, but were absent in 2017. The appearance of individuals with morphological anomalies was associated with copper or lead. The chemical data and structure of zooplankton communities indicated that the toxic pollution of Sorbulak decreased by 2017 compared to 2000–2002. Our results demonstrate that the structural variables of zooplankton communities could be successfully used to assess the water quality of water bodies with mixed pollution. We recommend using not only the traditional set of biological variables (abundance, biomass, diversity indices, and the average mass of an individual), but also data on the structure of species dominance, the sex structure of copepod populations, and the presence of individuals with morphological anomalies for monitoring of water bodies with mixed pollution.

Zooplankton as Indicator of the Ecological State of Protected Aquatic Ecosystems (Lake Borovoe, Burabay National Nature Park, Northern Kazakhstan)

The enrichment of the protected Borovoe Lake with nutrients has taken place within the last 100 years, from the moment the first resort was formed on its shores. The purpose of this study was to assess the current ecological state of Borovoe based on the structure of zooplankton. According to the chemical data, in the summer of 2019, the content of nutrients in the water was, relatively, not high; the content of heavy metals was very low. Twenty-seven species were found in zooplankton. The average abundance of zooplankton was 988.8 thousand ind./m3 with a biomass of 1.52 g/m3. Rotifera dominated. Cladocera sub-dominated. The Shannon index values were 2.31 bit/ind. and 2.57 bit/mg; the values of Clarke’s W-statistics and Δ-Shannon were negative. The abundance of zooplankton increased more than nine times, but the average individual mass of an organism decreased from 0.0112 to 0.0016 mg over the past decade. Despite the relatively low content of nutrients, the structure of zooplankton demonstrated that the nutritional load on Lake Borovoe is currently close to critical. Statistical mapping of the data and redundancy analysis (RDA) showed that the primary source of lake pollution is the village of Borovoe and sanatoriums located on the southeast and northwest coasts.

Self-purification ability of natural waters in the arid zones

The paper presents the analysis of literature data and research results on self-purification and self-purification ability of natural waters at arid zones (on example of closed Lake Balkhash). The self-purification processes are a combination of all natural (hydrodynamic, chemical, microbiological and hydrobiological) processes in contaminated natural waters. A large number of pollutants and specific (physical and geographical) conditions of reservoirs causes the complexity and variety of cleaning processes of natural waters. Large amounts of pollutants discharged into water reservoirs and drains impede the self-purification processes. It has been established that the sediments and clay of Lake Balkhash absorb the metal ions. Thus, the process of absorption of Mn2+ ions by clay minerals mainly occurs within the first three hours of contact, whereas sorption by slits continues until 10-15 days. The sediments are good absorbents for cadmium (90%), zinc (86%) and copper (78%). The sorption properties in the dynamic mode decreases in the row of zeolite (SEC = 1.02·10-3), then Fe (OH)3 (SEC = 0.28·10-3) and Al (OH)3 (SEC = 0.10·10-3 mmol-eq/g) with respect to Mn+2 ion with concentrations from 5.0 to 100 μg/L.