Absheron Peninsula's Coasts Under Threat: Satellite Data Reveals Rapid Degradation

The southern Absheron Peninsula is experiencing increasing ecological stress caused by both climatic shifts and anthropogenic pressures. To investigate these changes, researchers utilized multi-sensor satellite data, including Sentinel-2 optical data for water quality indicators such as Chlorophyll-a (Chl-a), Trophic State Index (TSI), Colored Dissolved Organic Matter (CDOM), and Land Surface Temperature (LST), estimated for 2021-2025. Further insights into physical drivers underlying these ecological changes were gained using ICESat-2 ATL03 photon data and GRACE/GRACE-FO sea level observations, providing a comprehensive view of the region's environmental health.

The analysis revealed concerning trends in water quality. Summer surface temperatures frequently surpassed 30 °C, overlapping with higher Chl-a and TSI values and highlighting the role of temperature in intensifying eutrophication risk. Moreover, land reclamation along the Zigh and Hovsan coastlines decreased water circulation, resulting in the boosting of CDOM and Chl-a accumulation, indicating a clear link between anthropogenic activities and water quality deterioration.

Beyond water quality, significant physical changes to the coastline were detected. ICESat-2 bathymetry analyses showed significant nearshore bathymetry changes, with depths decreasing from approximately 7 meters (2020-2021) to 2-3 meters in 2024. This 'shoaling' is attributed to sediment accumulation or coastal infilling, likely linked to reclamation activities and altered hydrodynamic conditions near the Zigh shoreline. These changes were further reinforced by GRACE/GRACE-FO observations of sea-level decline, underscoring the combined influence of hydrological change, sediment redistribution, and human-driven alterations on coastal morphology.

As lead author Ahadov notes in the paper, "Results underscore the pressing nature of the situation, with climate-driven sea-level decline, rising temperatures, and local anthropogenic activities jointly degrading water quality and reshaping bathymetry in the southern Absheron Peninsula." This integrated approach highlights the urgent need for enhanced wastewater management and sustainable coastal planning to protect the Caspian Sea's ecosystems.