On the transformation of the chemical composition of the Volga River discharge waters at the Caspian shallows

• Published in: Oceanology (Washington. 1965) Vol. 51; no. 5; pp. 796 - 803
• Main Authors: Vinogradova, E. L., Makkaveev, P. N., Melnikova, Z. G., Nalbandov, Yu. R., Stunzhas, P. A., Khlebopashev, P. V.
• Format: Journal Article
• Language: English
• Published: Dordrecht SP MAIK Nauka/Interperiodica 01-10-2011; Springer Nature B.V
• Subjects: Aquatic plants; Biofilters; Carbon dioxide; Chemical elements; Chemical oceanography; Dissolved inorganic carbon; Dissolved oxygen; Earth and Environmental Science; Earth Sciences; Freshwater; Groundwater discharge; Marine; Marine Chemistry; Oceanography; River discharge; River flow; Rivers; Caspian Sea; Volga River; Russia, Volga R; Eurasia, Caspian Sea; Shallow Area; Outer Edge; Volga Delta; Maximum Permissible Concentration; Dissolve Oxygen Content
• ISSN: 0001-4370; 1531-8508
• DOI: 10.1134/S0001437011050213

The Volga River discharge consists of the waters transferred by fast currents through channels and the waters which are passing through the shallow areas of the delta overgrown by cane. Using the hydrochemical data, it is possible to track distribution of the waters modified by “biofilters” of macrophytes in the delta shallows starting from the external edge of the delta. The main distinctive features of these waters are the high content of dissolved oxygen, the abnormally high values of the pH, and the low content of dissolved inorganic carbon (both total and as CO
2
). These waters extend in the shape of 1 to 3-km-wide strips at a distance of 20–40 km from the outer border of the delta. The analysis of the data obtained during the expeditions run by the Institute of Oceanology of the Russian Academy of Sciences in 2003–2009, along with archived and published data, show that such “modified” waters occur almost constantly along the outer edge of the Volga River delta.