Because of the shallow waters, the development of aquatic life in the Sea of Azov is more characteristic of a lagoon, and the plankton patterns are rather similar in the open sea and near the shores. Despite its shallowness, the water has low transparency, so bottom plants are poorly developed and most algae are of planktonic type. The sea is characterised by high concentrations of organic matter and long blooming periods. Another specific feature of the sea is the variable salinity – low in the large bays and higher in the open sea, especially near the Kerch Strait. Therefore, the plankton species are distributed inhomogeneously in the Sea of Azov. Although many additional species are brought in from the saltier Black Sea, most of them cannot adjust to the variable salinity of the Sea of Azov, except for the euryhaline species. About 600 species of planktonic algae are known in the Sea of Azov. The number of species is dominated by diatoms and green algae; blue-green algae and pyrophites are significant, and euglena and yellow-green algae form only 5% of the species. Green algae are mostly responsible for the colour of the sea in the satellite images (see photos above).