Caspian Basin

The landlocked Caspian Sea is the largest inland body of water on Earth. Surrounded by Azerbaijan, Iran, Kazakhstan, Russia, and Turkmenistan, the Caspian Sea is home to myriad ecosystems. At the meeting point of the Middle East, Europe, and Asia, the Caspian region includes steppe land in the north, cold, continental deserts and semi-deserts in the northeast and east, and warmer mountain and highland systems in the south and southwest. The coastal wetlands of the Caspian basin include many shallow, saline pools, which attract a variety of bird life and biodiversity over 400 species are unique to the Caspian. In addition, the sea s native sturgeon is famous the world around for the roe it produces sturgeon from the Caspian Sea accounts for approximately 90% of the world s caviar industry. 

The Black Sea region is also a very important communication center due to international transport corridor of energy flows from the Caspian basin to the West. 

Great Basin (Jones, 1966) or the Volga-Caspian Basin (Clauer et al., 1998), multiple sources of chemically distinct waters are generally associated with corresponding geologic settings. 

Figure 2.14 Distribution of superhydrostatic pressures of the groundwater in part of the South Caspian Basin near the Baku Archipelago, indicating lateral flow of groundwater through sand units from area III towards area I (from Bredehoeft et al., 1988. Reprinted by permission of the American Association of Petroleum Geologists).

Bredehoeft, J.D., Blyth, C.R., White, W.A. and G.B. Maxey, 1963. A possible mechanism for concentration of brines in subsurface formations. The American Association of Petroleum Geologists Bulletin, Vol. 47, no. 2, pp. 257-269 Bredehoeft, J.D., Djevanshir, R.D. and K.R. Belitz, 1988. Lateral fluid flow in a compacting sand-shale sequence South Caspian Basin. The American Association of Petroleum Geologists Bulletin, Vol. 72, no. 4, pp. 416-424... 

Bredehoeft, J., Djevanshir, R.D. and Belitz, K.R. 1988. Lateral fluid flow in a compacting sand-shale sequence south Caspian Basin. Am. Assoc. Pet. Geol. Bull., 72 416-424. 

Figure 1. The Caspian Sea and rivers of its basin. The Caspian Sea s states 1—Russia, 2— Kazakhstan, 3—Turkmenistan, 4—Iran, 5—Azerbaijan.

The Caspian Sea is the largest inland water body on earth (386,400 km2, maximum depth 1025 m). With its long history of oil and industrial development, the Caspian is often regarded as severely polluted and ecologically degraded. The North Basin of the Caspian Sea is a large (25% of the Caspian Sea surface area), shallow (median... 

Thus, at present, the input of unused DDT and HCH insecticides in water and bottom sediments of the rivers and reservoirs of the Caspian Sea basin is mainly connected with loss or leaching from old RPA or young LPA. As regards PCBs, their input is mainly related to industrial sources. The high toxicity of POCs for organisms and their persistence in the water and sediments are the principal forms of ecological risk for rivers and the Caspian Sea. The behavior of POCs in the northern part of... 

Oradovskii, S. G., Afanasyeva, N. A., Ivanova, T. A., Matveychuk, I. G. (1997). Assessment of trends of the chemical pollution level in the Russian basins of the Caspian, Black and Azov Seas during 1980-1995. Oceanology, 37(6), 862-867. 

The largest internal basins are the Black Sea and tte Caspian Sea. Tte salinity of surface waters in the Black Sea is about 17%o (half that of the Mediterranean), while in the Caspian Sea it is very low. 

Consideration of the impact of low-frequency fluctuations of climate on Caspian Sea level showed that the long-term variability of the level is connected mainly with SST anomalies in the eastern part of the tropical Pacific Ocean. It turns out that positive SST anomalies correlate with the growing rain rate in the Volga River watershed basin and vice versa. The main reason for variations in Caspian Sea level is the long-term dynamics of El Nino events, which should be considered as chaotic. 

At the end of the preceding century, an intensification of the studies of the Black Sea ecosystem occurred. Its necessity was mainly defined by three principal reasons the influence of the regional climate changes during the last decade of the last century on the entire Black Sea ecosystem the strongest impact of species-invaders on the pelagic and bottom biocenoses of the basin and catastrophic reduction in their commercial potential and, finally, the large-scale construction and plans of construction of object of oil and gas complex in the sea area such as the oil terminal of the the Caspian Pipeline Consortium (CPC) on the Russian shelf (2001), and the Blue Flow (2003) and Blue Flow - 2 (nearest future) underwater gas pipelines. 

Freshwater regressive basin occasionally connected with the Caspian Sea and inhabited by the Sea of Azov, freshwater and brackishwater fauna - salinity 2-7 %o... 

Brackishwater basin connected with the Caspian Sea and inhabited by brackishwater endemic species and immigrants from the Caspian Sea - salinity up to 15 96o... 

Fig. 2 Pleistocene basins of the Black Sea. 1-4 Types of the mollusk fauna 1 brackishwater fauna 2 Pliocene relics 3 Black Sea endemic species 4 Caspian immigrants. 5-6 Mediterranean fauna 5 stenohaline 6 euryhaline...

With respect to its area and the sea level height, the Early Chaudian sea did not exceed the present-day Black Sea basin. It was definitely not connected with the Mediterranean Sea and, probably, not with the Caspian Sea the latter suggestion may be inferred from the absence of Caspian mollusks in the Lower Chaudian deposits. Presumably, the climate of this epoch, which coincided with the first Pleistocene cooling over the Russian Plain, was cold open steppe landscapes existed in coastal lowlands and cold steppes were developed in the northern regions. 

The Uzunlarian transgressive stage represents the further evolution of the Old Euxinian basin and its transition from the brackish-water basin of Caspian type to a freshened marine basin with a salinity close to the present-day Black Sea value (about 18%o). 

The long-term evolution history (about 0.5 million years) of this basin, which is commonly referred to as the Pantikapean basin [7], consists of a series of stages that reflect the sequence of its evolution from the brackish-water basin of a Caspian type to a freshened marine basin (Black Sea type), normal marine basin (Mediterranean type), and, finally, to a strongly freshened basin (Azov type). 

About 15 000 years B.P., the waters of the Khvalynian transgression of the Caspian Sea overcame the Manych threshold (with an absolute mark of about 45 m) and started to enter the Black Sea basin. At the beginning of the transgression, the Kerch Strait and the Sea of Azov were dried here, drilling revealed [10,12,18] a system of major channels, via which the Caspian waters were dumped into the Black Sea. 

The end of the Caspian water supply to the Azov-Black Sea basin and the termination of the New Euxinian transgression occurred after 11000 years B.P., when the level of the regressing Khvalynian sea fell below the position of the Manych threshold. During the Holocene, there was no connection between the Caspian Sea and the Azov-Black Sea basin and the basins have been evolving independently. 

During the Pleistocene history of the Black Sea, a series of basins may be traced that are noticeably different in their hydrological and faunistic characteristics. The formation and evolution of these basins was defined by many factors, the principal factors being the availability of the connection with the Caspian and the Mediterranean seas, the character of the water exchange with... 

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