What did the Aral Sea look like before drying up? Let's talk about this.
Oddly enough, but the water of the Aral Sea is very poor in nutrient salts. The Aral water is very poor in phosphates and nitrates; the number of the former increases somewhat with depth, while the latter disappear altogether.
Silicon is richer in surface waters, mainly at river mouths, where it is supplied with river waters. Due to the low content of biogenic elements in the Aral Sea, there is no accumulation of organic matter consumed by the fauna.
Only in the estuarine areas are the waters rich in nutrient salts brought by rivers. In this regard, here, in shallow, well-heated areas, are concentrated the main fish spawning grounds, feeding grounds and growing fry.
The waves in the Aral Sea are determined by the wind, and since the wind is rarely strong here, the strength of the waves is most often measured by one or two points. In autumn and spring, when the strongest winds occur, the waves reach four to five points.
Because of the shallow water, short but steep waves are formed. They grow quickly and pose a great danger to small fishing vessels in case of sudden oncoming squalls.
The system of its currents is one of the peculiar features of the Aral Sea. Along the western coast, the current flows from south to north. North of about. The renaissance stream splits into two branches. One of them enters the Chernyshev Bay, forming a clockwise circulation there, and the other turns to the northeast.
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Passing between about. Barsa-Kelmes and the Kulandy Peninsula, it merges with the waters of the Syr Darya and moves south along the eastern coast. Fr. The Tolmachev current turns to the west, merges with the Amudarya waters, and follows to the northeast, closing the ring of the anticyclonic circulation of currents.
This flow pattern is generally directionally stable. The speeds depend on the wind. In light winds or calm weather, the currents of the Aral Sea have a speed of 0.2-0.4 knots. During prolonged winds of the north and north-east directions, the speed of currents can increase by 40-50%.
The highest turning speeds (up to 1 knot) are observed in the Muynak Bay and between the Vozrozhdenie and Barsa-Kelmes Islands. These currents cover a layer 10-20 m thick. In the center of the sea between 44 ° 40 'and 45 ° 15' N. sh. and 59 ° 40 'and 60 ° 20' E. there is a stagnant zone with an almost complete absence of currents.
Unlike other seas of the northern hemisphere, the waters of the Aral Sea move clockwise. There are various explanations for this feature. It is possible that the main reason for the anticyclonic movement of the Aral waters is the prevalence of northern winds over the Aral Sea.
These winds are characterized by a slight decrease in speed from east to west. The general circulation includes river waters, the desalination effect of which affects the north and center of the sea.
Rivers do not affect the nature of the movement of the Aral waters. Deeper than 20 m, the currents are almost invisible. Only in the western part at this depth are currents from north to south noted.
Like other closed basins of the desert zone, the Aral Sea is characterized by large fluctuations in water level. Over the centuries, sea level has been higher and lower than today.
Secular level changes occur due to changes in climatic conditions not only in the Aral Sea region, but also far to the south of it, in the mountains, where the Amu Darya and Syr Darya originate, the flow of which depends on climatic factors and ultimately determines the sea level height.
The Aral Sea level does not remain constant throughout the year, but changes depending on the season. Om also depends on the seasonal change in river flow and is in direct relationship with it: the larger the flow, the higher the sea level.
In summer, due to the melting of snow and glaciers in the mountains, the river flow increases, and, therefore, the level rises. In autumn and winter, runoff decreases and the level goes down. In different years, the magnitude of seasonal sea level fluctuations is different.
