In the Caspian Sea discovered zones of oxygen starvation

An expedition in the northwestern part of the Caspian Sea revealed zones with a reduced oxygen content in the bottom layer. This may be the result of a powerful flood and mudflows in Dagestan, which brought a large amount of organic substances into the sea, the press service of the Institute of Oceanology named after P. P. Shirshov RAS told TASS.

According to scientists, the phenomenon may be associated with difficult vertical exchange and insufficient oxygen supply to the bottom layer. Another possible reason is the anthropogenic factor: against the background of floods with villages in Dagestan, an impressive amount of organic matter could get into the waters of the Caspian Sea, the abundance of which leads to hypoxia zones. The exact cause will be determined by laboratory work.

During the expedition on the ship “Deneb” in the 12-mile and economic zones of the Russian sector of the sea, material was selected for suspended substances, plankton, zoobenthos and microplastics. Within the 12-mile zone of the Dagestan coast, zones with a reduced percentage of dissolved oxygen and the poverty of the composition of zooplankton were noted in the bottom layer. Scientists also recorded a shift in the warm layer of the sea compared to 2024. The temperature of about 20 degrees contributed to the growth of jelly plankton and a decrease in the density of crustaceans and larval forms of bottom organisms.

In general, the results indicate a stable state of the ecosystem of the Russian sector of the Caspian Sea, no potentially dangerous phenomena have been identified.