Dynamics of physicochemical and microbiological parameters of peloids of the Kuyalnitsky Estuary under the influence of the Black Sea’s water

Babov K., Arabadji M., Koieva K., Nikolenko S., Kysylevska A., Tsurkan O., Plakida A. Dynamics of physicochemical and microbiological parameters of peloids of the Kuyalnitsky Estuary under the influence of the Black Sea’s water. Arabian Journal of Geosciences. 2023; 16: 56. https://doi.org/10.1007/s12517-022-11066-6

The Kuyalnitsky Estuary is located on the northwestern coast of the Black Sea, north of Odessa, Ukraine. Its hydromineral base comprises silt-sulfide peloids – a complex and dynamic interaction system between the organo-mineral complex and microbiota sources. Shallowing of the reservoir reduces the water inflow from the catchment due to anthropogenic impact and climate change. Since 2014, the problem has been solved by filling the estuary basin with water from the Black Sea. We analyzed the dynamics of changes in the physicochemical and microbiological parameters of peloids after the launch of the Black Sea water. The study of the dynamics of mud solution mineralization of the peloids shows a significant increase from 234.00 g/l in 2015 to 324.03 g/l in 2020. Over the same period, there was a decrease in pH values from a neutral-weakly alkaline medium (7.15 c.u.) to a slightly acidic (5.80 c.u.) and an increase in the values of the Eh index from − 180 mV in 2015 to − 120 mV, which indicates the attenuation of the processes of peloidogenesis. A decrease in the mass fraction of organic carbon from 1.83 to 1.62% is an indicator of an insufficient supply of fresh organic matter for the processes of peloidogenesis. Microbiological indicators show the redistribution in the peloid-forming microbiota with the domination of saprophytic, butyric, ammonifying, and putrefactive bacteria. Research results prove that the launch of seawater into the estuary does not solve the issue of preserving its natural medicinal resources.