Fig. 12.

Causes and effects in the Aral Sea crisis. Hatched outlines show the extension of the sea after the regression had split it into two main bodies in the south and the Small Aral Sea in the north. (1) Diversion of water for irrigation resulted in (2) disastrously reduced inflow to the sea from ca.1960 onwards (3) Almost simultaneously planned species introductions seriously disturbed the native fauna (4) The reduced water inflow caused area regression, increased salinity and therefore serious reduction in biodiversity (5) Almost all fish disappeared with serious economic consequences for the human population (6) Sediment form the dried out sea bottom was blown into the air, causing very serious health problems for the human population (7) At the height of the area regression in 1990, the northern Small Aral Sea was connected to the vanishing Large Aral only through eastern Berg Strait, since the western Auzy-Kokaral Strait had dried out; a dam constructed in 2005 across the Berg Strait now retains inflowing water from the Syr Darya (8) Water level in the Small Aral Sea rapidly increased and salinity decreased; the fauna was reconstituted from refugial populations and fisheries recovered, where it again became an important commercial asset. (9) The larger part of the original Aral Sea continues to degrade into hypersaline water bodies and dried out salt flats with little or no metazoan life (10) The surrounding arid steppe now suffers from more extreme weather oscillations, since Aral waters no longer act as a buffer to temperature (11) In the future, climate caused, decreased precipitation at the sources of the two rivers will add to the shortage of water.