Science Fair Project Encyclopedia
The Aral Sea is an endorheic inland sea in Central Asia; it lies between Kazakhstan in the north and Karakalpakstan, an autonomous region of Uzbekistan, in the south. Since the 1960s, the Aral Sea has been shrinking, as the rivers that feed it were diverted by the USSR for irrigation. The Aral Sea is badly polluted, largely as the result of weapons testing, industrial projects, and fertilizer runoff before the breakup of the Soviet Union.
The major ecological problem is that diversion of the Amu Darya and Syr Darya rivers for irrigation has shrunk the Aral Sea dramatically; the Aral Sea has been drying up for about 40 years. This has brought about a number of ecological problems both for the sea and for the surrounding area.
The Soviet Union decided in 1918 that the two rivers that fed the Aral Sea—the Amu Darya in the south and the Syr Darya in the northeast—would be diverted for irrigating the desert in order to grow rice, melons, cereal, and, above all, cotton; this was part of the Soviet plan for cotton, or "white gold," to become a major export. (This did eventually end up becoming the case, and even today Uzbekistan is one of the world's biggest exporters of cotton.)
The irrigation canals began to be built on a large scale in the 1930s. Many of the irrigation canals were poorly built, letting water leak out or evaporate; from the Kara Kum canal, the largest in Central Asia, perhaps 30–70% of the water went to waste. Still today only 12% of Uzbekistan's irrigation canal length is waterproofed.
By 1960, somewhere between 20 and 50 cubic kilometers of water were going to the land instead of the sea. Thus, most of the sea's water supply had now been diverted, and in the 1960s, the Aral Sea began to shrink. From 1961 to 1970, the Aral's sea level fell at a mean of 20 cm a year; in the 1970s, the average rate nearly tripled to 50–60 cm per year, and by the 1980s it continued to drop, now with a mean of 80–90 cm each year. Even seeing this, the rate of water usage for irrigation continued to increase: the amount of water taken from the rivers doubled between 1960 and 1980; the cotton production nearly doubled in the same period.
The disappearance of the lake was no surprise to the Soviets; they expected it to happen long before. The USSR apparently considered the Aral to be "nature's error," and a Soviet engineer said in 1968 that "it is obvious to everyone that the evaporation of the Aral Sea is inevitable."
The sea's surface area has now shrunk by approximately 60 percent, and its volume by almost 80 percent. In 1960, the Aral Sea was the world's fourth-largest lake, with an area of approximately 68,000 km≤ (about the size of the Republic of Ireland), and a volume of 1100 km≥; by 1998, it had dropped to 28,687 km≤, and eighth-largest. Over the same time period, the salinity of the Aral Sea has increased from about 10 g/l to about 45 g/l.
In 1987, the continuing shrinkage split the lake into two separate bodies of water, the North Aral Sea and the South Aral Sea ; an artificial channel was dug to connect them, but that connection was gone by 1999, as the two seas continued to shrink.
Work is being done to preserve the North Aral Sea, including the construction of dams to ensure that fresh water continues to flow into it. In October 2003, the Kazakh government announced a plan to build a concrete dam (Dike Kokaral) separating the two halves of the Aral Sea, in order to raise the water level of the North Aral Sea and reduce its salinity. For financial reasons, the (much larger) South Aral Sea has been abandoned to its fate. As it dries, it is leaving behind vast salt plains, producing dust storms, and making regional winters colder and summers hotter. Attempts to mitigate these effects include planting vegetation in the newly exposed seabed.
As of summer 2003, the South Aral Sea is vanishing faster than predicted. The surface is now 30.5 meters above sea level (3.5 meters lower than predicted in the early 1990s), and the water is 2.4 times as salty as the ocean. In the deepest parts of the sea, the bottom waters are saltier than the top, and not mixing. Thus, only the top of the sea is heated in the summer, and it evaporates faster than would otherwise be expected. Based on the recent data, the western part of the South Aral Sea is expected to be gone within 15 years; the eastern part could last indefinitely.
The ecosystem of the Aral Sea and the river deltas feeding into it has been nearly destroyed, not least because of the much higher salinity. The land around the Aral Sea is also heavily polluted, and the people living in the area are suffering from a lack of fresh water, as well as from a number of other health problems—the receding sea has left huge plains covered with salt and toxic chemicals, which are picked up, carried away by the wind as toxic dust, and spread to the surrounding area; the population around the Aral Sea now shows high rates of certain forms of cancer and lung diseases, as well as other diseases. Crops in the region are also destroyed by salt being deposited onto the land. The town of Moynaq in Uzbekistan had at one point a thriving harbor and fishing industry employing approximately 60,000 people; now the town lies miles from the shore. Fishing boats lie scattered on dry land that was once covered by water; many of them have been there for 20 years. Almost the only fishing company left in the area has its fish shipped from the Baltic Sea, thousands of miles away.
The tragedy of Aral coast was portrayed in "Psy" ("Dogs") motion picture by Dmitriy Svetozarov (USSR, 1989). The film was shot on location of the actual ghost town, showing scenes of abandoned buildings and scattered vessels.
Possible Solutions to Problems
Many different solutions to the different problems have been suggested, ranging in feasibility and cost. These include:
- Improving the quality of irrigation canals ;
- Installing desalinisation plants;
- Charging farmers to use the water from the rivers;
- Using different cotton species, which use less water;
- Melting glaciers in Siberia, and moving the water to refill the Aral.
- Using less chemicals on the cotton
Bioweapons facility on the Vozrozhdeniya Island
In 1948, a top-secret Soviet bioweapons laboratory was established on the island situated in the middle of the Aral sea (now a disputed territory between Kazakhstan and Uzbekistan). The exact history, functions and current status of this facility have not yet been disclosed. The base was abandoned in 1992 following the disintegration of the Soviet Army. Scientific expeditions (incl. American) proved this had been a site for production, testing and later dumping of pathogenic weapons. A joint international program is underway for cleaning such dumps, particularly those of anthrax. Amateur studies also claim finding on-site evidence of testing those weapons on humans (probably prisoners), including pregnant women.
External links & further reading
- BBC article by David Shukman on a study that finds high levels of DNA damage that could explain the region's abnormally high cancer rate; Muynak, Uzbekistan, 29 June 2004
- New Scientist article, 21 July 2003
- BBC article on planned dam, 29 October 2003
- State of Environment of the Aral Sea Basin (extensive information about the Aral Sea ecosystem)
- People & the Planet: Requiem for a dying sea
- 365 satellite images of the Aral Sea on NASA's Visible Earth website
- www.american.edu: Aral Sea Loss and Cotton
- Earthshots: satellite images of environmental change
- Anthrax 'time bomb' ticking in Aral Sea, researchers say - CNN's report on bioweapons dump on Vozrozhdeniya Island
- The Secrets of Vozrozhdeniya Island (in Russian)
- "Psy" motion picture page (in Russian)
- Bissell, Tom. "Eternal Winter: Lessons of the Aral Sea Disaster." Harper's, April 2002, pp. 41–56.
- Ellis, William S. "A Soviet Sea Lies Dying." National Geographic, February 1990, pp. 73–93.
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