Small Aral Sea

Today at the location of the former Aral Sea there are three remnant water bodies the Small Aral Sea, Western Large Aral Sea, and Eastern Large Aral Sea (see Fig. 2). In June 2009 the Western and Eastern Large Aral Sea were still coimected by a small, shallow, and narrow channel in the northern part of both basins (Fig. 3). The Aral Sea lost its economic importance, and the aftermath of its degradation represents a serious threat to the local population due to a lack of fresh water, water quality loss, salinization of soils, dust and salt storms, climate deterioration, various diseases, etc. 

Fig. 2 The map of the Aral Sea coast line changes during 1957-2008. Figures in circles 1 - western Large Aral Sea, 2 - eastern Large Aral Sea, 3 - bay Tshchebas detached in 2004, 4 - Small Aral Sea...

The differences in the hydrological regimes of the two lakes have thus led to stabilization of the Small Aral Sea level and continued desiccation and salinization of the Large Aral Sea. All the above has been widely documented in several articles [11, 14, 16, 18-24], and Fig. 5 of [19]. 

Aladin NV, Cretaux J-F, Plotnikov IS, Kouraev AV, Smurov AO, Cazenave A, Egorov AN, Papa F (2005) Modem hydro-biological state of the Small Aral Sea. Environmetric 6(4) 375-392... 

When mineralisation reached 36 ppt, the number of bacteria increased. According to Sulalina and Smurov [51] in the small Aral Sea and Butakov Bay the number of bacteria varied from 0.7 to 2.4 x 10 cells ml with a tendency of increasing to the bottom. At that time bacterioplankton were mainly represented by rod-like, coccoid, filamentous and spiral forms. 

Zavialov PO, Ni AA, Kudy shkin TV (2008) Five years of field hydrographie research in the Large Aral Sea (2002-2006). J Mar Syst. doi 10.1016/j.jmarsys.2008.03.013 Aladin NV, Filippov AA, Plotnikov IS et al (1998) Changes in the stmeture and function of biological communities in the Aral Sea, with particular reference to the northern part (Small Aral Sea), 1985-1994 a review. Int J Salt Lake Res 7 301-343... 

All is not lost, however. The government of Kazakhstan has moved forward to restore the Small Aral Sea. After several attempts to build earthen barriers to arrest the flow from the Small Aral to the Large Aral, a concrete wall now helps to return water in the Small Aral. Its level has steadily risen, as the government assures a steady flow of Syrdarya water into its delta. The fishing industry, too, has been resurrected in this region. 

Small, 1., van der Meer, J., Upshur, R. E. (2001, June). Acting on an environmental health disaster The case of the Aral Sea. Environmental Health Perspectives, 109(6), 547-549. 

Fig. 4 Scheme of the bottom sediments of the Aral Sea [10]. (1) Sand (2) oolitic-calcareous sand (3) coarse silt (4) fine silt (5) clayey-calcareous mud (6) deltaic clayey mud of the northern bays and small Sea... 

From the early twentieth century when instrumental observations were started and till the mid-1960s the water balance of the Aral Sea was quasistationary. The annual inflow of river waters (52-56 km ) and atmospheric precipitation (8-10 km ) managed to compensate for the evaporative water losses (62-66 km ). Small fluctuations of the sea level around 53 m over the ocean level were observed and this level was assumed to be average over a many-year period. 

The average cmitent of phosphates varied in some years from 1.0 to 4.2 mg m and, in some cases, dropped even to analytical zero. During the whole observation period their maximum content was registered in August 1949 in the southeastern part of the sea - over 20 mg m [8]. The Small Sea was one of the areas with the higher phosphate content (1.0-4.6 mg m as well as the mouth areas of the Amudaiya and Syrdarya. The low level of phosphates was recorded in the western area and in the eastern shallow part of the sea - from 0 to 1.0 mg m . The highest values of phosphate content were usually observed in the surface layer, but with depth it sometimes dropped even to analytical zero (at 10-20 m depths). Some enrichment of the surface water layer with phosphates occurred, thanks to the river flow. The seasonal variations in the phosphate content in the Aral Sea, unlike other seas, were revealed rather weakly. On a year-to-year scale the average phosphate values increased in the water abundant years and dropped with the decrease of flow from the rivers. 

As is known, fixed nitrogen is present in seas and lakes in several forms. Nitrates produce the greatest influence on biotic productivity. They, similar to phosphates, are present in the Aral Sea in very low concentrations. Thus, the nitrate nitrogen content in the open part of the Large Sea never exceeded 5 mg m and only in the mouth areas of rivers was it somewhat higher. The nitrate values in the Small Sea were higher. Their content in the surface waters varied from 7.0 to 15.0 mg m and in the bottom layer - from 1.0 to 3.0 mg m . ... 

There is hardly any other example of the degradation of a sea (one of the largest lakes on the Earth) within one generation but this really is what happened to the Aral Sea. We can recollect cases of desiccation of small lakes, such as Lon-Nor in China. 

Such conditions are formed due to frequent recurrence of weather with a small cloud fraction. The number of cloud-free days is the greatest in summer months (Fig. la). In the coastal zone of the Aral Sea compared to inland regions the... 

Wind velocities in winter markedly exceed the summer ones (Fig. 2d). Practically everywhere in the Aral region their mean monthly values exceed 3 ms reaching in some places even 5 ms and more, which makes these territories rather attractive in terms of small-scale wind energy development. Strong winds and loose soils -the consequence of the Aral desiccation - create a serious environmental problem as salt and sand drift from the exposed seabed in addition to transfer of chemicals that were once brought into the sea from the fields with river waters. Every year from coastal areas that were up to quite recently at the bottom of the Aral Sea the wind puts adrift more then 75,000 tons of sand and salts [5] and transports them hundreds of kilometers. This causes progressive soil salinization in the Aral Region. 

Because of the small depths of the Aral Sea winds blowing even with small velocities create short, but steep waves. Over the flat territories of the Aral region and over the sea surface the wind velocities often reach storm magnitudes, hi the... 

Herein is described the natural fluctuatirms of the Amudarya and Syrdarya annual flow, the variatiOTis in the river inflow to the deltas and to the Aral Sea that occurred (and are still in progress) as a result of economic activities in the drainage basins of the abovementioned rivers. This process is a crucial factor leading to the shallowing and division of the Aral Sea into two parts the Large Sea and Small Sea. 

Fig. 1 The Aral Sea catchment area 1 Large Sea 2 Small Sea 3 Dam in the Berg Strait 4 Peninsula (former island) Vozrozhdeniya...

The long-term fluctuations of annual volumes of the natural flow of the Amudarya and Syrdarya rivers (water resources), total inflow to the deltas and to the Aral Sea and main annual water levels of the Large and Small Sea are shown in Fig. 6. 

Fig. 6 Total natural flow of the Amudarya and the Syrdarya rivers, inflow to the deltas and to the Aral Sea, water levels in the Aral Sea 1 natural flow 2 and 3 inflow to the deltas and to the Sea 4 water level in the Large Sea 5 water level in the Small Sea...

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