Varna Bay (Bulgaria): research based on the water-related challenges

Many factors influence bay waters, including greater concentration of people in cities, industrial production, how land is used, dynamics of flow in water systems, and climate change. Water management remains one of the greatest human challenges. Scientists continue to respond to water-related challenges through the research to improve both human and environmental health. Study in the Varna Bay, providing key knowledge on hydrological and hydrochemical characteristics, was done over 2015–2018. Unified methods for marine waters were used. An increase in SST was ascertained. The range of SSS monthly fluctuations increased almost twice compared to a long-term range. Nitrate nitrogen range was bigger than phosphate phosphorus range. A sharp increase in organic matter was ascertained but generally the range decreased compared to a long-term range.