Caspian Depression
The southern region of the depression, or the north coast of the Caspian Sea, is characterized by the large development of damp sites resulting from tidal phenomena. The depression is also home to many insect species, with several thousand different species likely living in the region around the Caspian Sea. Studies have shown that water pollution, mostly coming from the Volga River, poses a serious threat to the biodiversity of the Caspian Depression. Water pollution is contributed mainly by industrial, agricultural, and household discharges.