Kamis, 10 Desember 2020

Small Aral Sea brings hope for Lake Balkhash - Science Magazine


In the recent Letter “Save Kazakhstan's shrinking Lake Balkhash” (16 October, p. 303), A. Ussenaliyeva calls for international attention to the ecological crisis now facing Lake Balkhash. Similar problems face other water bodies without effluents, such as the Great Salt Lake (1) and Lake Urmia in Iran (2). A parallel crisis severely damaged the Aral Sea (2, 3), located between Kazakhstan and Uzbekistan. The action taken in response could provide a model for lakes suffering from desiccation.

Starting around 1960, diversion of inflowing water for irrigation purposes caused an accelerating regression and salinization of the Aral Sea (3). By 1990, the remaining waters sustained only organisms able to thrive in polyhaline conditions, and commercial fisheries, formerly of prime importance, had vanished (4). The desiccation also caused multiple severe health problems due to airborne dust (5). In 1992, a primitive dam was constructed across the Berg Strait to retain water in the northern Small Aral Sea, demonstrating a cost-effective way to maintain a low level of salinity. With financial help from the World Bank, the structure was later replaced by a stronger dam (3, 6), which succeeded in rapidly restoring the Small Aral.

With increasing water volume and decreasing salinity, species that had become extinct during the regression crisis repopulated the sea by natural means from refugia in the affluent Syr Darya river system (7). Commercial fisheries that depend on the lake are thriving again (7, 8). The Aral Sea crisis foreshadows what may face Lake Balkhash if no timely action is taken. It also shows that a relatively small financial effort can yield substantial results. The Aral Sea is surrounded by several countries that should, jointly with the international community, take renewed action to preserve even more of this system. This coalition should also lend its expertise to determine how attention and investment can best prevent a similar ecological crisis at Lake Balkhash and the Great Salt Lake.

The Link Lonk

December 11, 2020 at 02:05AM

Small Aral Sea brings hope for Lake Balkhash - Science Magazine



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