Large,deep salt lakes: a comparative limnological analysis

Among athalassic salt lakes of the world large, deep lakes are rare. A comparative analysis of Mono(USA), Walker (USA), Qinghai Hu (China), Shala (Ethiopia), Van (Turkey), Panggong Tso (Indian Tibet) and Karakul (USSR) (with emphasis on the two italicized lakes) reveals a number of ecological similarities. The criteria for selection were a mean depth greater than 15 m, an area greater than 100 km² and a salinity greater than 10 g l^?1 and less than 100 g l^?1. The Aral and Caspian Seas were excluded because of the relict marine affinities of their biota. Large, deep salt lakes are located at moderate to high altitude in mountainous terrain: They stratify and mix at least once per year, and dissolved oxygen is depleted in the hypolimnia of most. The lakes contain alkaline, sodium rich waters with considerable chloride, sulfate and carbonate plus bicarbonate. Phosphate concentrations are usually high while inorganic nitrogen varies widely. Secchi disk transparency ranged from < 1 m to ca. 20 m. Supersaturation of dissolved oxygen, abundant animals and seasonally high algal populations indicate that some of the lakes are productive. All except Mono contain fish.