Lake Titikaka

Lake Titicaca (; es, Lago Titicaca ; qu, Titiqaqa Qucha) is a large freshwater lake in the Andes mountains on the border of Bolivia and Peru. It is often called the highest navigable lake in the world. By volume of water and by surface area, it is also the largest lake in South America.Grove, M. J., P. A. Baker, S. L. Cross, C. A. Rigsby and G. O. Seltzer 2003 Application of Strontium Isotopes to Understanding the Hydrology and Paleohydrology of the Altiplano, Bolivia-Peru. ''Palaeogeography, Palaeoclimatology, Palaeoecology'' 194:281-297.

Lake Titicaca has a surface elevation of . The "highest lake" claim is generally considered to refer to commercial craft. Numerous smaller bodies of water (that are not considered lakes) around the world are at higher elevations. For many years, the largest vessel afloat on the lake was the 2,200-ton (2,425 U.S. tons), SS ''Ollanta''. Today, the largest vessel is most likely the similarly sized train barge/float '' Manco Capac'', operated by PeruRail.

Other cultures lived on Lake Titicaca prior to the arrival of the Incas. In 2000, a team of international archaeologists and divers found the ruins of an underwater temple, thought to be between 1,000 and 1,500 years old, most likely built by the Tiwanaku people. The ruins have been measured to be . The temple was accompanied by a village, some roads, terraces for farming and a retaining wall that ran for 800 metres.

Overview

The lake is located at the northern end of the endorheic Altiplano basin high in the Andes on the border of Peru and Bolivia. The western part of the lake lies within the Puno Region of Peru, and the eastern side is located in the Bolivian La Paz Department.

The lake consists of two nearly separate subbasins connected by the Strait of Tiquina, which is across at the narrowest point. The larger subbasin, ''Lago Grande'' (also called ''Lago Chucuito''), has a mean depth of and a maximum depth of . The smaller subbasin, Wiñaymarka (also called ''Lago Pequeño'', "little lake"), has an average depth of and a maximum depth of .Dejoux, C. and A. Iltis (editors) (1992). ''Lake Titicaca: A Synthesis of Limnological Knowledge''. 68. Kluwer Academic Publishers, Boston. The overall average depth of the lake is .

Five major river systems feed into Lake Titicaca. In order of their relative flow volumes these are Ramis, Coata, Ilave, Huancané, and Suchez. More than 20 other smaller streams empty into Titicaca. The lake has 41 islands, some of which are densely populated.

Having only a single season of free circulation, the lake is monomictic,Cross, S. L., P. A. Baker, G. O. Seltzer, S. C. Fritz and R. B. Dunbar (2001). Late Quaternary Climate and Hydrology of Tropical South America Inferred from an Isotopic and Chemical Model of Lake Titicaca, Bolivia and Peru. ''Quaternary Research'' 56(1):1–9. and water passes through Lago Huiñaimarca and flows out the single outlet at the Río Desaguadero, which then flows south through Bolivia to Lake Poopó. This only accounts for about 10% of the lake's water balance. Evapotranspiration, caused by strong winds and intense sunlight at high altitude, balances the remaining 90% of the water loss. It is nearly a closed lake.

Since 2000, Lake Titicaca has experienced constantly receding water levels. Between April and November 2009 alone, the water level dropped by , reaching the lowest level since 1949. This drop is caused by shortened rainy seasons and the melting of glaciers feeding the tributaries of the lake. Water pollution is also an increasing concern because cities in the Titicaca watershed grow, sometimes outpacing solid waste and sewage treatment infrastructure. According to the Global Nature Fund (GNF), Titicaca's biodiversity is threatened by water pollution and the introduction of new species by humans. In 2012, the GNF nominated the lake "Threatened Lake of the Year".

Temperature

The cold sources and winds over the lake give it an average surface temperature of . In the winter (June – September), mixing occurs with the deeper waters, which are always between .

Name

Neither the protohistoric nor prehistoric name for Lake Titicaca is known. Given the various Indigenous groups that occupied the Lake Titicaca region, it likely lacked a single, commonly accepted name in prehistoric times and at the time the Spaniards arrived.Standish, C. (2005) ''Ancient Titicaca: The Evolution of Complex Society in Southern Peru and Northern Bolivia.'' Oakland, California, University of California Press. 338 pp.

The terms ''titi'' and ''caca'' can be translated in multiple ways. In Aymara, ''titi'' can be translated as either puma, lead, or a heavy metal. The word ''caca'' (''kaka'') can be translated as white or grey hairs of the head and the term ''k’ak’a'' can be translated as either crack or fissure, or alternatively, comb of a bird. According to Weston La Barre, the Aymara considered in 1948 that the proper name of the lake is ''titiq’aq’a,'' which means gray, discolored, lead-colored puma. This phrase refers to the sacred carved rock found on the Isla del Sol.La Barre, W. (1948) ''The Aymara Indians of the Lake Titicaca Plateau, Bolivia.'' American Anthropological Association Memoir. no. 68, pp. 208–210. In addition to names including the term ''titi'' and/or ''caca,'' Lake Titicaca was also known as ''Chuquivitu'' in the 16th century. This name can be loosely translated as lance point. This name survives in modern usage in which the large lake is occasionally referred to as ''Lago Chucuito.''

Stanish argues that the logical explanation for the origin of the name Titicaca is a corruption of the term ''thakhsi cala,'' which is the 15th- to 16th-century name of the sacred rock on the Isla del Sol.Bauer, B., and Stanish, C. (2001) ''Ritual and Pilgrimage in the Ancient Andes.'' Austin, Texas, University of Texas Press. 314 pp. Given the lack of a common name for Lake Titicaca in the 16th century, the Spaniards are thought to have used the name of the site of the most important indigenous shrine in the region, ''thakhsi cala'' on the Isla del Sol, as the name for the lake. In time and with usage, this name developed into ''Titicaca.''

Locally, the lake goes by several names. The southeast quarter of the lake is separate from the main body (connected only by the Strait of Tiquina) and the Bolivians call it Lago Huiñaymarca (also Wiñay Marka, which in Aymara means the Eternal City) and the larger part Lago Chucuito. The large lake also is occasionally referred to as Lago Mayor, and the small lake as Lago Menor. In Peru, these smaller and larger parts are referred to as Lago Pequeño and Lago Grande, respectively.

Ecology

Lake Titicaca is home to more than 530 aquatic species.Kroll; Hershler; Albrecht; Terrazas; Apaza; Fuentealba; Wolff; and Wilke (2012). ''The endemic gastropod fauna of Lake Titicaca: correlation between molecular evolution and hydrographic history.'' Ecol Evol. Jul 2012; 2(7): 1517–1530.

The lake holds large populations of water birds and was designated as a Ramsar Site