Algae bloom formation in the Baltic Sea/Curonian Lagoon

The Curonian Spit is a long and thin sand-dune spit that separates the Curonian Lagoon from the Baltic Sea. Formed by the accumulation of glacial debris, and sand carried by the wind, it is a UNESCO World Heritage Site, whose northern part lies in Lithuania. The Spit is an important ecological area and home to several migratory bird species, such as herons.

On July 10th, 2024, one of the Copernicus Sentinel-2 satellites acquired this image of swirling green blooms in the Baltic Sea and Curonian Lagoon. 

Nutrient concentration and water temperature are important factors of algae growth, creating favourable conditions for bloom formation, especially inside the lagoon.  Sentinel-2 plays an important role in water quality monitoring for inland and coastal waters, but calibration with local measurements remains essential.