WATER-QUALITY AND LIMNOLOGICAL FEATURES OF A HIGH-ALTITUDE ANDEAN LAKE, CHUNGARA IN NORTHERN CHILE

The water quality of lake Chungara (4,520 ma.s.l.), in the Unesco worl d biosphere reserve Lauca, northern Chile was investigated between Oct ober 1982 - April 1984. Additional water quality information and data over the trophic status of the lake were collected during shea visits carried out in April 1980, October 1985 and Jannuary 1986. Lake Chunga ra can be classified as a cold-polymictic, high altitude, tropical, vo lcanic, and saline lake. Cations in lake Chungara ranks as: Mg+2 > Na > Ca+2 > K+. The chemistry of water in lake Chungara is also dominate d by: SO42-, CO2, HCO3-, Li, and Al. Large concentrations of P-PO4, up to 10 mu M 1(-1) were measured in the lake water. Nitrate and Silica in the lake, are in moderate concentrations. The phytoplankton in Lake Chungara is dominated by Chlorophyta and Bacillariophyta. Zooplankton is dominated by calanoids and cladocerans. Fishes are present: Tricho mycterus sp. (Trichomicteridae) and Orestias sp. (Cyprinodontidae). La ke Chungara is a sanctuary for an abundant migratory avifauna. The tro phic status of this lake was estimated according to chlorophyll a conc entration (1.49 mu g 1(-1)) as oligomesotrophic, and according to phot osynthetic activity (0.0428 g C m(-2) h(-1)) as meso-eutrophic. Concur rence of unique physical, chemical and biological features make lake C hungara worth of further specific intensive studies and long term moni toring.