Contribution to the Limnology of High Montain Lakes in Central America
Tropical high mountain lakes have been defined as cold polymictic lakes which throughout the year exhibit frequent circulation periods and in general occur above 3800 m where temperatures in lakes normally do not exceed 12-15 "C, (LOFFLER, 1960(LOFFLER, , 1964(LOFFLER, , 1968). I n wet, tropical high mountain zones or "Paramos" the diurnal range of temperature may be less than 1 "C, and lakes with almost thermostatic conditions result. Such extreme "Paramo" lakes are usually found in connection with more or less permanent fog (e.g. in the Ecuadorian and Colombian Andes). Less extreme examples occur not only in South America, where most of the tropical high mountain lakes are located, but also in East Africa, Borneo and Indonesia, New Guinea and Central America. Another type of lake is encountered in "Punas" or dry tropical high mountain zones. This exhibits a diurnal variation in temperature because of a range of air temperature of sometimes more than 50 "C (e.g. Andes of northern Chile). Outside South America Puna type lakes are less common, and have only been found on Mauna Kea (MACIOLEK 1969), on Kilimanjaro and in locations of Guatemala which will be described in this paper.
Except for a few geographic observations (WEYL 1956 a, b) no information