Aral Sea ecosystem
The Aral Sea ecosystem, once one of the world's largest lakes, has undergone a significant transformation resulting in an environmental crisis. Located in Central Asia, bordered by Kazakhstan to the north and Uzbekistan to the south, the Aral Sea was historically vital for the region, providing fish resources and facilitating transportation. However, since the 1960s, extensive irrigation practices initiated by the Soviet Union diverted the rivers feeding the sea for agricultural purposes, leading to a dramatic reduction in water levels and increasing salinity. This has severely impacted biodiversity, with only six out of thirty-two fish species surviving, and has devastated the local fishing industry.
The ecological decline has also had profound social and health repercussions for the surrounding communities, contributing to increased rates of various health issues due to pollution and diminished agricultural yields. Additionally, the climate has shifted, resulting in harsher winters and hotter summers, while the landscape has changed as vegetation adapted to desert conditions. Recent efforts, such as the construction of the Kok-Aral Dam, have shown some promise in restoring parts of the North Aral Sea, yet much of the region continues to grapple with the consequences of this environmental calamity. Ongoing agricultural ambitions and natural resource extraction further complicate the recovery of the Aral Sea ecosystem.
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Aral Sea ecosystem
- Category: Inland Aquatic Biomes.
- Geographic Location: Central Asia.
- Summary: The Aral Sea, once one of the largest lakes in the world, has become a large-scale environmental tragedy, although it now shows some signs of partial recovery.
The Aral Sea was once known as the fourth-largest inland sea of the world by area, with a surface area of 25,500 square miles (66,100 square kilometers) and a mean depth of 53 feet (16.1 meters), reaching up to 221 feet (68 meters) in the deepest portions. This inland lake is located in central Asia and is bordered by the countries of the north and Uzbekistan to the south, both previously members of the Soviet Union. It was characterized by once having more than 1,000 islands; its name stems from that fact.
The Aral Sea region is a semi-desert, with an annual rainfall of merely eight inches (20 centimeters) and a continental climate (one marked by strong demarcations in seasonal temperatures). The Aral Sea receives most of its water from the Amu Darya River in the south and the Syr Darya River in the north, keeping its salinity content at roughly one percent. Geographic conditions of the area have strongly influenced human activities; people in the northern portion have long-raised livestock, while the ones in the southern region depended on vegetative agriculture. The Aral Sea was of great importance for the region because, besides being an abundant fish resource, it facilitated transportation by boat throughout the provinces.
The story of prosperity ended when, in the 1960s, the Soviet Union diverted the rivers that fed the Aral Sea to serve an ambitious plan to irrigate thirsty crops like rice, cotton, and cereals in the desert. Irrigation channels were grossly inefficient, with an estimated 30 to 75 percent of the water evaporating or leaking away. The farmers did not practice crop rotation, and the extensive monoculture demanded ever-higher quantities of fertilizer and pesticides. The runoff of these chemicals into the shrinking Aral Sea became a big pollution issue. Even today, only 12 percent of Uzbekistan's irrigation channel network has antifiltration linings. Although Uzbekistan became a large exporter of cotton, the Aral Sea has contracted ever since, becoming a great calamity to the region.
In 1987 the continued dwindling away of the water level left the Aral Sea split in two, as the North Aral Sea and the South Aral Sea. In 1998, the sea was just the eighth-largest inland sea, with a water surface area reduced by about 60 percent to 11,000 square miles (29,000 square kilometers). Salinity increased from 10 parts per thousand (ppt) to about 45 ppt, making a substantial negative impact in the region. (It would later increase to 100 ppt, about three times as salty as seawater). The decrease in water depth caused surface water temperature to increase during summer, promoting a greater evaporation rate. To try to save the North Aral Sea, Kazakhstan built a dam in 2005 called the Kok-Aral Dam. The 86-million-dollar project separates the northern and southern parts of the Aral Sea. In 2007, the steady decline in the water volume caused the South Aral Sea to be divided into western and eastern basins. By 2009, the North Aral Sea was still alive, but the eastern lake in South Aral disappeared while the western lake shrank to a thin strip of water. By 2011, the Kok-Aral dam was credited with helping restore the North Aral Sea's water salinity level to pre-1960 conditions.
Although the Aral Sea also receives about 5,200 cubic yards (4,000 cubic meters) of water per year from groundwater discharge that finds its way from the Tian Shan and Pamir mountain ranges, this is insufficient to replenish the shrinking sea and stop desiccation or salt intrusion.
Extended Effects
As a result of the Aral Sea shrinkage in recent decades, the diversity and amount of fish radically dropped because they could not adapt to the far higher salinity levels. Of 32 species of fish, only six were known to have survived. Thus, the fishing industry that was once prosperous collapsed. Muskrat trapping, which once yielded a half-million pelts per year from the wetlands around the Amu Darya River and Syr Darya River deltas, also dwindled drastically.
Shipping trade suffered because the water receded far away from the ports of Moynak to the south and Aralsk to the north. Sixty thousand jobs were lost by the mid-1980s, impacting such water-hungry industries as paper manufacturing. To survive, many men migrated to other regions but left their wives and children behind.
Beyond losing the use of abundant water, the plants, animals, and people of the Aral Sea region also suffered secondary effects. When the sea level dropped by 45 feet (14 meters), some 200,000 tons of salt and sand were exposed on the seabed. The scorching heat dried the debris, and the wind carried this salt and sand as far as 190 miles (300 kilometers) every day. The whitish, high-salt layer covering the land surface destroyed many agricultural fields and pastures. Nowadays, before the sowing season, the salt on the land surface must be washed away, which in turn requires more water. Crop yields have diminished; the shortage of forage also has a negative effect on cattle and domestic animals.
The constant use of pesticides and fertilizers in the cotton and rice fields has been a public health concern. The heavily contaminated agricultural waters go back to the rivers and eventually to the Aral Sea. Since most people obtain their drinking water directly from the Syr Darya River, they are highly exposed to contaminants, heavy metals, increased salinity, and pesticides. Health effects are noticeable in the population, in particular in children. Diseases like tuberculosis, viral hepatitis, eye problems, throat cancer, anemia, allergies, digestive disorders, kidney and liver ailments, and congenital disabilities have increased. And the windblown dust seems responsible for many respiratory illnesses.
The climate itself has also changed due to the waste of the Aral Sea. Winters are colder, while summers are hotter. Precipitation has decreased, extending drought periods and shortening the growing seasons. Biodiversity has been affected; about half of the native bird and mammal species have withdrawn from the region. Vegetation has also shifted from trees and shrubs to xerophytes and halophytes, plants better tuned to true desert conditions.
The former major island of Vozrozhdeniya in the Aral Sea became a peninsula in 2001, and in 2008, the island merged with the mainland. In 1948, the Soviet Union had a bioweapons laboratory there, but in 1992, the lab was abandoned. Surveys of the area showed that the site was used for the production, testing, and disposal of biological weapons like typhus, botulinum toxin, plague, tularemia, and brucellosis. The health risk is that since Vozrozhdeniya is no longer an island, weaponized organisms such as fleas and rodents might reach the cities and spread. Thus, in 2002, the United States and the local government put into action a plan to decontaminate ten anthrax burial sites, and according to the Kazakh Scientific Center for Quarantine and Zoonotic Infections, all were decontaminated.
Despite the health, social, and economic repercussions of diverting water from the rivers that feed the Aral Sea into water-intensive crops, the governments of Uzbekistan and neighboring Turkmenistan still plan to enlarge the cotton and rice production in the area. Furthermore, in 2005, they signed an agreement to explore the seabed of the South Aral Sea for gas and oil. As of 2010, they had extracted 654,000 cubic yards (500,000 cubic meters) of gas. Natural gas drilling continued into 2021 in Uzbekistan on the dry seabed of the Aral Sea, with plans to produce 66.1 billion cubic meters by 2030. To combat soil conditions and damage in the region, the Environmental Restoration of the Aral Sea implemented a three-year $1.35-million plan. From 2021 to 2024, it planned to improve soil conditions and vegetation in the dry seabeds of the Aral Sea through afforestation.
Bibliography
Aladin, Nickolay V., et al. "Aral Sea: Water Level, Salinity and Long-Term Changes in Biological Communities of an Endangered Ecosystem—Past, Present and Future." Natural Resources and Environmental Issues, vol. 15, no. 36, 2009, pp. 1-6.
Micklin, Philip, and Nikolay Aladin. "Reclaiming the Aral Sea." Scientific American, vol. 164, no. 4, 2008, pp. 64-71.
"USAID Environmental Restoration of the Aral Sea." USAID Central Asia, 2 Nov. 2021, www.usaid.gov/central-asia-regional/fact-sheets/environmental-restoration-aral-sea-i-eras-i-activity. Accessed 28 Oct. 2024.
"Uzbekistan Implements New Project to Produce 1.2 Billion Cubic Metres of Gas Annually." The Tribune, 20 July 2022, www.thetribune.com/uzbek-state-oil-and-gas-firm-to-issue-700-mln-bonds-2/. Accessed 28 Oct. 2024.
Walters, Pat. "Aral Sea Recovery?" National Geographic, 2 Apr. 2010, news.nationalgeographic.com/news/2010/04/100402-aral-sea-story. Accessed 28 Oct. 2024.