The vicious cycle
Environmental degradation
According to forecasts, the sea level in the Caspian Sea in scenarios with medium and high GHG emissions will decrease by 9-18 m by the end of this century, which is caused by global warming and a significant increase in lake evaporation, which is not balanced by an increase in river runoff or precipitation.
A decrease of 9-18 m will mean that the vast shelf of the northern Caspian, the Turkmen shelf in the southeast and all coastal areas in the middle and southern Caspian will rise above the sea surface. In addition, the Kara-Bogaz-Gol Bay on the eastern outskirts will be completely dehydrated.
In general, the surface area of the Caspian Sea will decrease by 23% with a drop in sea level by 9 m and by 34% with a drop by 18 m (see the picture below).”
Matthias Prange, Thomas Wilke, Frank P. Wesselingh “The other side of sea level change” read the full article atnature.com
Unique Pontocaspian biota
The Black Sea-Caspian Sea region hosts a unique aquatic biota. These Pontocaspian biota evolved in the region in the past millions of years to withstand the unusual salinity settings in lakes and seas. Sturgeons and Caspian seals are well known representatives, but Pontocaspian faunas contain hundreds of invertebrate species such as molluscs, crustaceans, worms and also fish that are unique to the region.
In the Black Sea Basin habitat degradation and nutrient pollution are major drivers, in the Caspian Sea it is a combination of invasive species, pollution and overfishing whereas the Aral Sea has simply vanished with its biota.
In general the awareness of Pontocaspian biota is low and needs improvement in order to foster effective conservation of these unique ecosystems and biota.
Research by the project “PRIDE: Pontocaspian rise and demise“ Naturalis Biodiversity Center (Netherlands): Frank Wesselingh, Koos Biesmeijer, Aleksandre Gogaladze, Sabrina van de Velde.
Pusa caspica
The Caspian seal is one of the endangered endemic Caspian species that will be seriously affected by the exposure of the northern Caspian shelf and the reduction of winter sea ice cover due to rising temperatures. Today, at least 99% of the puppy breeding sites are located there.
Matthias Prange, Thomas Wilke, Frank P. Wesselingh “The other side of sea level change”read the full article at nature.com
Largest landlocked sea on the Planet Earth is eutrophying
"The competition over extracting the energy resources of the Caspian Sea together with the major anthropogenic changes in the coastal zones have resulted in increased pollution and environmental degradation of the sea. We provide the first evaluation of the spatiotemporal variation of chlorophyll-a (Chl-a) across the Caspian Sea. Using remotely sensed data from 2003 to 2017, we found that the Caspian Sea has suffered from a growing increase in Chl-a, especially in warmer months. The shallow parts of the sea, near Russia and Kazakhstan, especially where the Volga and Terek rivers discharge large nutrient loads (nitrogen- and phosphorus-rich compounds) into the sea, have experienced the highest variations in Chl-a. The Carlson's trophic state index showed that during the study period, on average, about 12%, 26%, and 62% of the Caspian Sea's area was eutrophic, mesotrophic, and oligotrophic, respectively. The identified trends reflect an increasing rate of environmental degradation in the Caspian Sea, which has been the subject of conflict among its littoral states that since the collapse of the Soviet Union have remained unable to agree on a legal regime for governing the sea and its resources".
Modabberi, Noori "Caspian Sea is eutrophying: the alarming message of satellite data"