Pioneer limnological observations on the developed ecosystem of a permanent lake in Abu-Dhabi Desert, U.A.E

摘要

In arid regions, wetlands and salt lakes are the most productive environments, whether natural or man-made. In these environments, water is the primary factor influencing plant and animal life (WILLIAMS 1993, 1998, SADA 2001, ZHENG 2001). Despite its subtropical arid nature, the Gulf region hosts several wetlands represented by the mangrove environments of the coastal areas. These wetlands are in stark contrast to the remainder of the Arabian Peninsula, which is characterized by deserts with ephemeral salt lakes that form immediately after rainfalls on low-lying areas with hypersaline substrates. In these latter environments, there are no permanent all-season saline lakes. However, in 1982 a permanent lake formed within the desert of Abu-Dhabi (largest emirate of the United Arab Emirates), due to an unplanned discharge of secondary treated wastewater from Al-Marfaq sewage treatment plant into a neighbouring area of sabkha. Subsequent small discharges have maintained the lake as a permanent body of water. The lake is fed by the continuous supply of treated water and also by saline drainage and runoff from the nearby Al-Wathba Camel Race Track. Evaporation is the main factor responsible for the water level decrease of the lake. Daily evaporation varies between 8000 m~3 in winter and 22 000 m~3 in summer.