Phytoplankton Spectral Pigment Indices in the Lakes of the City of Kyiv

Phytoplankton annual dynamics and ecological structure were studied in the Irpin River (the right bank tributary of the Kyiv Reservoir) near the town of Irpin (50°31'N, 30°15' E). On the whole, 121 algal species of nine divisions were identified. Chlorophyta (57) and Bacillariophyta (27) included the largest number of species. During the year, phytoplankton species composition, and also the complex of dominant species, varied significantly. This is supported by rather low values of the Sorensen coefficient of community similarity (on the average 53% and 41%, respectively). The quantitative indices of its development also varied significantly. The lowest number of species (25), cell numbers, and biomass of plankton algae (on the average 662 thousand cells/L and 0.165 mg/L) were registered in winter and the largest number of species (83) - in summertime. At the same time, the highest cell numbers and biomass (19,480 thousand cells/L and 5.143 mg/L) were observed in autumn (in September). Direct significant correlations were established between phytoplankton quantitative indices and water temperature. However, it has been found that phytoplankton annual dynamics in the Irpin River depended not only on water temperature, but also on the trophic status of the watercourse. As a result of the performed bioindication analysis, it has been found that in terms of such indices as the contribution of species - indicators of the trophic status, nutrition type, and organic contamination, and also in terms of phytoplankton biomass, the waters of the studied section of the Irpin River can be characterized as eutrophic ones, which is supported by the data of direct hydrochemical measurements. The pattern of phytoplankton annual dynamics was characterized by the formation of the peak of its numbers and biomass in early autumn. The maximum quantitative indices of phytoplankton development were conditioned by intensive development of blue-green algae with a predominance of Aphanizomenon flos-aquae (L.) Ralfs belonging to water bloom forming species. Such pattern of phytoplankton annual dynamics is typical to eutrophic water bodies. The obtained information on the development of algae in the Irpin River in the period preceding military activities can be used to assess their consequences.

Phytoplankton Annual Dynamics and Ecological Characteristics in the Irpin River (Ukraine) Prior to the Beginning of Military Activities

Shevchenko,

Klochenko,

Sereda

2024

Changes in Phytoplankton of the Irpin River (Ukraine) as a Result of Military Activities in Its Basin

Shevchenko,

Sereda,

Nezbrytska

et al. 2024

Phytoplankton structure was studied in a comparative aspect (before and after the beginning of military activities) in the section of the Irpin River belonging to a large lowland rivers flowing in silicate rocks. On the whole, 132 algal species of seven divisions were found in the water column of the Irpin River during the period of investigations. Bacillariophyta and Chlorophyta were highly diverse in their species composition (37.1 and 31.1% of the total number of species). The distribution of plankton algae at the studied stations even within the same massif of surface waters was non-uniform in terms of species composition (the Sorensen coefficient of community similarity on the average was 37%), species richness (18-49 species), cell numbers (1930 thousand cells/L - 24,450 thousand cells/L), and biomass (2.118 mg/L - 20.374 mg/L). Almost different algal species dominated at various stations (14 species among 20 dominated only at one station). Compared to the previous period of investigations (2018), the number of plankton algal species in the studied section of the Irpin River somewhat increased (from 121 to 132). Phytoplankton taxonomic structure also somewhat changed. The contribution of Bacillariophyta increased from 22.3 to 37.1% and that of Cyanoprokaryota - from 9.1 to 12.1%. In this case, the contribution of Chlorophyta decreased from 47.1 to 37.1%. The quantitative indices of phytoplankton development increased. The maximum numbers increased from 19,480 thousand cells/L to 24,450 thousand cells/L, whereas the maximum biomass - from 5.143 mg/L to 20.374 mg/L. As a consequence of the impact of military activities on phytoplankton of the Irpin River, it is possible to consider an increase in the number of its species, the maximum numbers and biomass, as well as the contribution of water bloom forming blue-green algae in the estuarine section of the Irpin River due to the disturbance of hydromorphology and the income of an additional amount of nutrients from flooded territories, which can lead to the formation of such a negative phenomenon as water bloom in this section of the river.

Epiphyton Pigment Indices in the River Section of the Kaniv Reservoir (Ukraine)

Medved',

Kharchenko

2024

The content of photosynthetic pigments (chlorophyll a, b, c and carotenoids) was studied in algal epiphyton of nine species of higher aquatic plants of various ecological groups occurring in the river section of the Kaniv Reservoir. It has been found that these indices varied over a wide range. Thus, in the fouling of emergent plants, the content of chlorophyll a was 0.9 μg/g of the dry mass of plant substratum, in epiphyton of submerged plants it varied from 15.4 to 62.4 μg/g, and in that of plants with floating leaves-from 3.1 to 11.0 μg/g. The content of chlorophyll b and c in epiphyton of submerged plants accounted for 1.0 and 8.5 μg/g, respectively, in that of plants with floating leaves - 0.5 and 2.1 μg/g, and in the fouling of emergent plants - 0.1 and 0.2 μg/g. The concentration of carotenoids in the fouling of emergent plants was 0.7 μgSPU/g of the dry mass of plant substratum, in epiphyton of submerged plants it varied from 13.2 to 49.3 μgSPU/g, and in that of plants with floating leaves it was within 2.5-9.5 μgSPU/g. It has been found that the content of chlorophyll a and carotenoids in algal epiphyton of higher aquatic plants correlates with its biomass.