19 июня 2013 16:22

Aral Sea stops dwindling

ПОДЕЛИТЬСЯ

The Aral Sea that has been dwindling since the 1960s has finally stabilized, RIA Novosti writes citing deputy director of Oceanology Institute of Russian Science Academy Pyotr Zavyalov. The Aral Sea started drying out because the Syrdarya and Amudarya rivers that fed it were diversion by the Soviet Uion to water cotton fields. In his report on the man-induced impact on the rivers, Zavyalov said that the water table of the formerly one of the four largest lakes in the world with an area of 68,000 square kilometers shrank 4-fold and the volume of its water reduced 10-fold after the 1960s. The water salinity increased sharply. The shrinking of the Aral Sea is often referred to as "one of the planet's worst environmental disasters." The region's once prosperous fishing industry was destroyed together with the sea's fish that became largely extinct because of the extreme salinity, bringing unemployment and economic hardships to the local population. The Aral Sea region is also heavily polluted because harsh winds pick up dust and salt from the dried bottom and carry the for miles, with consequent serious public health problems. A multi-year tree planting campaign is being held by Kazakhstan to make the dried bottom green, restore its flora and tackle the health problem. Massive amount of trees - mostly saksaul that is capable of growing in deserted areas - are being planted every year as part of the campaign. The retreat of the sea also caused a local climate change, with summers becoming hotter and drier, and winters becoming colder, longer and more severe. In an ongoing effort in Kazakhstan to save and replenish the North Aral Sea, a dam project was completed in 2005 with a support from the international community. After the dam was in place the water level in the North Aral Sea rose by 24 m by 2008 from its lowest level in 2007. Its salinity dropped and fish is again found in sufficient numbers to sustain some fishing. The maximum depth of the North Aral Sea was 42 m in 2008. The dammed North Aral Sea is the best part of the sea in terms of both depth and salinity. “The analysis shows that the sea has come close to the balance, as its table has shrunk so much that the evaporation have decreased as well. Now even the insignificant remaining river flows and underground waters help the sea to maintain the balance,” the scientist said. Despite of the extreme salinity of the water, an ecosystem has formed at the Aral Sea. “The Aral Sea’s ecosystem is quite specific, but alive,” Zavyalov said. A recent expedition of the Oceanology Institute discovered 40 types of phytoplankton and big amounts of zooplankton represented mainly by only species, Artemia parthenogenetica. This is not the first case of catastrophic drying out in the history of the Aral Sea, Zavlyalov said. The sea was in a similar condition around 2 thousand years ago, as well as in the Middle Age period, around 400-500 years ago. “We are saying it cautiously, but we believe that the dwindling of the Aral Sea has both man-induced and natural causes behind it,” the scientist said.


The Aral Sea that has been dwindling since the 1960s has finally stabilized, RIA Novosti writes citing deputy director of Oceanology Institute of Russian Science Academy Pyotr Zavyalov. The Aral Sea started drying out because the Syrdarya and Amudarya rivers that fed it were diversion by the Soviet Uion to water cotton fields. In his report on the man-induced impact on the rivers, Zavyalov said that the water table of the formerly one of the four largest lakes in the world with an area of 68,000 square kilometers shrank 4-fold and the volume of its water reduced 10-fold after the 1960s. The water salinity increased sharply. The shrinking of the Aral Sea is often referred to as "one of the planet's worst environmental disasters." The region's once prosperous fishing industry was destroyed together with the sea's fish that became largely extinct because of the extreme salinity, bringing unemployment and economic hardships to the local population. The Aral Sea region is also heavily polluted because harsh winds pick up dust and salt from the dried bottom and carry the for miles, with consequent serious public health problems. A multi-year tree planting campaign is being held by Kazakhstan to make the dried bottom green, restore its flora and tackle the health problem. Massive amount of trees - mostly saksaul that is capable of growing in deserted areas - are being planted every year as part of the campaign. The retreat of the sea also caused a local climate change, with summers becoming hotter and drier, and winters becoming colder, longer and more severe. In an ongoing effort in Kazakhstan to save and replenish the North Aral Sea, a dam project was completed in 2005 with a support from the international community. After the dam was in place the water level in the North Aral Sea rose by 24 m by 2008 from its lowest level in 2007. Its salinity dropped and fish is again found in sufficient numbers to sustain some fishing. The maximum depth of the North Aral Sea was 42 m in 2008. The dammed North Aral Sea is the best part of the sea in terms of both depth and salinity. “The analysis shows that the sea has come close to the balance, as its table has shrunk so much that the evaporation have decreased as well. Now even the insignificant remaining river flows and underground waters help the sea to maintain the balance,” the scientist said. Despite of the extreme salinity of the water, an ecosystem has formed at the Aral Sea. “The Aral Sea’s ecosystem is quite specific, but alive,” Zavyalov said. A recent expedition of the Oceanology Institute discovered 40 types of phytoplankton and big amounts of zooplankton represented mainly by only species, Artemia parthenogenetica. This is not the first case of catastrophic drying out in the history of the Aral Sea, Zavlyalov said. The sea was in a similar condition around 2 thousand years ago, as well as in the Middle Age period, around 400-500 years ago. “We are saying it cautiously, but we believe that the dwindling of the Aral Sea has both man-induced and natural causes behind it,” the scientist said.
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