Sediments and Phytoplankton in Southern Caspian Sea39.0N 50.9E
Sediments pour into the southeastern part of the Caspian Sea, giving the waters a milky blue color. These sediments add extra nutrients to the water, encouraging the growth of phytoplankton, as is evidenced by the green and blue color.
Bordering the southern part of the sea is the Alborz mountain range, in northern Iran. The range stretches from the borders of Azerbaijan and Armenia in the northwest to the southern end of the Caspian Sea, and ending in the east at the borders of Turkmenistan and Afghanistan. It forms a barrier between the south Caspian and the Qazvin-Tehran plateau.