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Results of Long-Term Bacterioplankton Monitoring in the Northwestern Black Sea
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 15th International Conference Monitoring of Geological Processes and Ecological Condition of the Environment, Nov 2021, Volume 2021, p.1 - 5
Abstract
Purpose of the work. Study of the long-period changes in bacterioplankton abundance in the northwestern Black Sea (NWBS) under external factors. Data and Methods. The data used were collected during integrated environmental monitoring in the open coastal NWBS areas in 1978- 1997, near the Zmiinyi Island in 2003–2020 and in the Odesa Bay in 2016–2017. Total bacteria number was assessed by direct count method under microscope on membrane filters. The results of study. Maximal values of bacterioplankton number ((1.0–7.2)∙106 cells/ml) were observed in early 90s of the past century. In 2003–2020 bacterioplankton abundance was 1.6- fold lower than in 1983–1997. Mesotrophic status of water (<2.0∙106 cells/ml) was registered in 68–89% of samples, eutrophic - in 11–32% of samples only. Bacterioplankton abundance in the Odesa Bay is 1.2-fold higher than near the Zmiinyi Island coast. Significant statistical relationships between bacterioplankton abundance and chlorophyll ‘a’ and salinity were identified. Conclusions. Quantitative changes of the NWBS bacterioplankton under the influence of allochthonous substance brought by rivers were calculated. Tendency of the surface waters’ eutrophic status lowering by 40% on bacteria number in 2003–2020 compared with 1990–1995 were identified. Dominant majority (80%) of observations performed in the past 18 years gives evidence of waters’ mesotrophic status.