The Sevastopol seashore is influenced by a variety of anthropogenic and natural factors, which can be particularly pronounced in enclosed bays. The objective of this study is to analyse the spatial and temporal variability of hydrological and hydrochemical parameters and the modern state of plankton communities of the Sevastopol seashore. The variability of hydrochemical indicators of water, phytoplankton and meroplankton was studied in 2020-2022 in Kamyshovaya, Kazachya, Kruglaya, Streletskaya, Sevastopol and Karantinnaya Bays. The hydrochemical parameters (salinity, biochemical oxygen demand over five days BOD₅, permanganate index, silicon content, mineral and organic forms of nitrogen and phosphorus) were determined according to generally accepted methods. The Redfield stoichiometric ratios were applied in order to ascertain the limiting nutrient factor. The species composition, abundance and biomass of phytoplankton and meroplankton were determined. In comparison to data collected 20 years ago, an increase in surface water pollution (BOD₅ and permanganate index exceeding maximum permissible values) was observed on the seashore of Sevastopol. Biogenic elements (nitrogen, phosphorus, and silicon compounds) varied widely. The study found that limiting factor for phytoplankton vegetation was nitrogen in spring, silicon in summer, and phosphorus in summer and autumn. No phytoplankton blooms were recorded during the study period. Mass development of diatoms and coccolithophores was observed in spring. In summer and autumn, the abundance and biomass of planktonic microalgae decreased to minimum values. Relative synchrony of seasonal dynamics of meroplankton density was observed: in all Sevastopol bays minimum values were registered in the cold period of the year, whereas maximum values were recorded in the warm period when the water warmed up above 14.5°C. Comparative analyses and quantitative assessments of plankton dynamics in bays, differing in hydrological and hydrochemical environmental parameters, can contribute to the assessment of the functional response of Black Sea coastal ecosystems to anthropogenic and natural factors.
About the authors:
Natalya V. Pospelova, Leading Research Associate, A. O. Kovalevsky Institute of Biology of the Southern Seas of RAS (2 Nakhimov Av., Sevastopol, 299011, Russian Federation), Ph.D. (Biol.), ORCID ID: 0000-0002-3165-2090, Scopus Author ID: 56884605100, ResearcherID: C-7572-2016, nvpospelova@ibss-ras.ru
Sergey V. Shchurov, Research Associate, A. O. Kovalevsky Institute of Biology of the Southern Seas of RAS (2 Nakhimov Av., Sevastopol, 299011, Russian Federation), ORCID ID: 0000-0002-8913-2637, Scopus Author ID: 57214992790, ResearcherID: AAC-9044-2022, skrimea@mail.ru
Nelya P. Kovrigina, Senior Research Associate, A. O. Kovalevsky Institute of Biology of the Southern Seas of RAS (2 Nakhimov Av., Sevastopol, 299011, Russian Federation), Ph.D. (Geogr.), ORCID ID: 0000-0002-6734-8285, Scopus Author ID: 6507114864, ResearcherID: AAC-9395-2022, npkovrigina@yandex.ru
Elena V. Lisitskaya, Senior Research Associate, A. O. Kovalevsky Institute of Biology of the Southern Seas of RAS (2 Nakhimov Av., Sevastopol, 299011, Russian Federation), Ph.D. (Biol.), ORCID ID: 0000-0002-8219-4616, Scopus Author ID: 6504112143, ResearcherID: T-1970-2017, lisitskaya@ibss-ras.ru
Oleg A. Troshchenko, Research Associate, A. O. Kovalevsky Institute of Biology of the Southern Seas of RAS (2 Nakhimov Av., Sevastopol, 299011, Russian Federation), Ph.D. (Geogr.), ORCID ID: 0000-0001-5200-9996, Scopus Author ID: 57218589904, ResearcherID: AAC-9364-2022, oleg_tr59@mail.ru
Contribution of the authors:
Natalya V. Pospelova – literature review on the study problem, analysis and interpretation of phytoplankton results, statistical analysis, conclusion drawing
Sergey V. Shchurov – concept development, problem statement, literature review on the study problem, analysis and interpretation of hydrological and hydrochemical results, conclusion drawing
Nelya P. Kovrigina – analysis and interpretation of hydrological and hydrochemical results, conclusion drawing
Elena V. Lisitskaya – literature review on the study problem, analysis and interpretation of meroplankton results, conclusion drawing
Oleg A. Troshchenko – analysis and interpretation of hydrological and hydrochemical results, conclusion drawing
All the authors have read and approved the final manuscript.