Ecological assessment of Shabla Tuzla Lake using satellite methods for the period 2017–2024

Shabla Tuzla is a saline lake-lagoon located approximately 3.7 km east-northeast of the town of Shabla, Bulgaria. The lake is separated from the Black Sea by a sandbar. During the summer months, the lake often nearly dries up. Its bottom is covered with therapeutic mud (hydrogen sulfide sludge), with reserves exceeding 200,000 tons, which are used for mud therapy. The wetland is of critical importance for the conservation of rare and endangered animal species and habitats. Shabla Tuzla falls within two categories of the European Ecological Network NATURA 2000. To support the work of local authorities and conservation organizations, an eight-year monitoring period (2017–2024) was conducted using satellite data. Recent advancements in high-resolution satellite imagery and data from the European Space Agency's Sentinel missions have significantly enhanced the ability to monitor ecological and hydrological processes in this region. The Sentinel-2 satellites, equipped with multispectral sensors, are particularly well-suited for detailed land and vegetation monitoring, while the Sentinel-3 satellites provide critical data on surface temperature, ocean color, and altimetry. These datasets provide comprehensive long-term information on water and environmental resources, facilitating the examination of trends such as variations in water levels, shifts in vegetation patterns, and the detection of potential contamination sources. This research employs Sentinel-2 and Sentinel-3 satellite data to investigate the spatiotemporal dynamics of the area between 2017 and 2024, offering critical insights into ongoing environmental changes and supporting informed strategies for sustainable management and conservation. An index-based classification was used in the study, for classifying the contents within the wetlands boundaries. The results demonstrated the effectiveness of these indices in facilitating accurate mapping and monitoring of wetland areas, providing valuable insights into their ecological characteristics and changes over time.