Showing papers on "Secchi disk published in 1983"
TL;DR: A comparative analysis of athalassic salt lakes of the world large, deep lakes are rare as discussed by the authors reveals a number of ecological similarities, such as abundant animals, abundant animals and seasonally high algal populations indicate that some of the lakes are productive.
Abstract: 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.
69 citations
TL;DR: It is concluded that single factor theories, those which ascribe the maximum depth of penetration to a single variable (e.g., light, temperature, hydrostatic pressure), are all deficient, and that the actual limitation is brought about by a combination of factors.
31 citations