Dezvoltarea fitoplanctonului fluviului Nistru și lacului de acumulare Dubăsari în condițiile impactului factorilor naturali și antropici

The article presents the results of study of qualitative and quantitative indicators of phytoplankton of the Dniester River within the Republic of Moldova and Dubasari reservoir in 2020. In phytoplankton compositions of the Dniester River were identified 64 species, Dubasari Lake – 56 species. The numbers of phytoplankton changed within the limits 0,39 to 16,99 mln. cel/l with biomass 0,7-17,19 g/m3 in Dniester River and in Dubasari Lake – 3,47-14,83 mln. cel/l with biomass 4,76-11,29 g/m3. The values of saprobic indexes, estimated on the basis of species-indicators from phytoplankton composition, which are in proportion of 60% typically β-mezosaprobic, confirm the following: the water quality of Dniester River and Dubasari Lake in the period of 2020 year was satisfactory for the development of phytoplankton and was attributed mainly to II-III (good-moderately polluted) quality classes.

Assessment of phytoplankton composition and physicochemical parameters of Omasi rice field, Anambra State, Nigeria

The microalgae and physicochemical parameters of floodwater of Omasi rice field in Anambra State, Nigeria were studied. Samples for the studies were collected at monthly intervals. The microalgae were studied using light microscopy and identified with taxonomic keys, text books and photograph materials from the internet. The physicochemical parameters and coliform content of the floodwater were analysed using the methods described by the American Public Health Association. Simple means of the parameters and percentages of the algal populations were calculated, while Pearson correlation (p ≤ 0.05) was used to check for significance of the relationships between the investigated parameters. A total of 12 algal taxa belonging to Chlorophyta (48.99%), Cyanophyta (32.89%), Euglenophyta (10.07%), and Bacillariophyceae (8.05%) were recorded in decreasing order of abundance. Water temperature ranged from 26-38 °C with mean of 33.3 ± 2.56 °C; colour ranged from 15-175 Hazen units with mean of 86.25 ± 33.19 Hazen units; depth of water ranged from 7-10.5 cm with mean of 9.38 ± 0.8 cm. Ranges of nitrates and phosphates with their respective means were 0.5-1.8 mg/l (0.86±0.31 mg/l) and 0.79-1.96 mg/l (1.18±0.28 mg/l). Omasi rice field supported the growth of diverse algal groups and species; this may be as a result of available nutrients and good climate as can be deduced from the correlation analyses. Omasi rice field is typical of tropical freshwaters and some tropical rice fields that have been studied in terms of microalgal diversities and some physicochemistry

Summer plankton of high mountain Lake Dzhulukul (Altai, Russia) in August 2020

The summer phytoplankton composition of high mountain Lake Dzhulukul located in Altai Mountainsat the source of Chulyshman River was studied in August 2020. Under the electron microscopic examination of thephytoplankton samples algae from four taxa groups – Chrysophyta, Bacillariophyta, Chlorophyta and Euglenophyta wererevealed, that has been supplemented the list of algae for the lake. Stomatocysts of chrysophycean algae various in shapeand structure have been revealed firstly for the lake algaflora.

The seasonal dynamics of phytoplankton and water quality in the Prut River lower sector

The article presents the results on qualitative and quantitative indicators of phytoplankton of the Prut River lower sector within the Republic of Moldova in 2018-2020. In phytoplankton compositions 72 species were identified. Seasonal and long-term patterns of phytoplankton development have been established in Prut River lower sector. The numbers of phytoplankton changed within the limits 1,06 to 20,32 mln. cell/l, with biomass 1,23-21,64 g/m3. The values of saprobic indexes, estimated on the basis of species-indicators (52 species) from phytoplankton composition, which are in proportion of 58% typically β-mezosaprobic, confirm the following: the water quality of lower Prut River sector in the period 2018-2020 was satisfactory for the development of phytoplankton and was attributed mainly to II-III (good-moderately polluted) quality classes.