The marine ecosystem can be affected by various anthropogenic activities, including wastewater pollution, due to population growth in coastal areas. The impact of nutrients and microorganisms from wastewater treatment plants on the bacterial community in coastal waters is poorly understood. Therefore, we focused our study on the response of marine bacterial metabolism to the addition of wastewater in microcosm experiments. We found that nutrient uptake from wastewater reduced the C:N molar ratio of dissolved organic matter in the experimental bottle and enhanced bacterial growth, respiration, and production. The highest bacterial density was measured in bottles with unfiltered wastewater, which also contained bacteria from wastewater treatment plants. Calculations showed that bacteria consumed most of the assimilated carbon in the respiration process, which is consistent with the low values of bacterial growth efficiency. Pathogenic organisms may also enter the sea with the wastewater, which can potentially include bacteria of the genus Vibrio. In the second part of the thesis, we focused on pure Vibrio cultures. We exposed Vibrio isolates to growth media with different nutrient concentrations. Growth, respiration, and production of each isolate were highest at the nutrient conditions most similar to the isolation site, suggesting good bacterial adaptation to the environmental conditions from which strains were isolated.
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