Lake Titicaca (; ; and ) is a large lake in the Andes mountains on the border of Bolivia and Peru. It is often called the highest navigable lake in the world. It is often listed as a freshwater lake, though its waters are slightly brackish. Titicaca is the largest lake in South America, both in terms of the volume of water and surface area.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.Rigsby, C., P. A. Baker and M. S. Aldenderfer 2003 Fluvial History of the Rio Ilave Valley, Peru, and Its Relationship to Climate and Human History. Palaeogeography, Palaeoclimatology, Palaeoecology 194:165-185 It is the 18th largest lake in the world. It has a surface elevation of .
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.Roche, M. A., J. Bourges, J. Cortes and R. Mattos (1992). Climatology and Hydrology of the Lake Titicaca Basin. In Lake Titicaca: A Synthesis of Limnological Knowledge, edited by C. Dejoux and A. Iltis, pp. 63–88. Monographiae Biologicae. vol. 68, H. J. Dumont and M. J. A. Werger, general editor. Kluwer Academic Publishers, Boston. 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.Mourguiart, P., T. Corrége, D. Wirrmann, J. Argollo, M. E. Montenegro, M. Pourchet and P. Carbonel (1998). Holocene Palaeohydrology of Lake Titicaca Estimated from an Ostracod-Based Transfer Function. Palaeogeography, Palaeoclimatology, Palaeoecology 143:51–72. and water passes through Lago Huiñaimarca and flows out the single outlet at the Río Desaguadero,Baucom, P. C. and C. A. Rigsby 1999 Climate and Lake Level History of the Northern Altiplano, Bolivia, as Recorded in Holocene Sediments of the Río Desaguadero. Journal of Sedimentary Research 69(3):597–611. 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. Its waters are slightly brackish, with UNESCO reporting its salinity as ranging from 5.2-5.5 parts per 1000. It is nearly a closed lake.Talbi, A., A. Coudrain, P. Ribstein and B. Pouyaud (1999). Computation of the Rainfall of Lake Titicaca Catchment During the Holocene. Géosciences de Surface 329:197–203.
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.Carlos Valdez: Lake Titicaca at dangerously low level – website of the Sydney Morning Herald (accessed 2009-11-28)Lake Titicaca evaporating away (video) – report by al Jazeera (accessed 2009-11-28) 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. A 2011 United Nations report found alarming concentrations of cadmium, arsenic, and lead in various parts of the lake. In 2012, the GNF nominated the lake "Threatened Lake of the Year".
Name
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 several 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 the 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.
Highest lake With a surface area of and an elevation of , Lake Titicaca is often called the highest navigable lake in the world. That claim is generally considered to refer to commercial craft. Numerous smaller lakes around the world are at higher elevations, such as the crater lake of Ojos del Salado volcano in Chile, which at an elevation of is the overall highest lake in the world, and the Lake Puma Yumco in Tibet, which at an elevation of is the highest large lake in the world. For many years, the largest vessel afloat on Lake Titicaca 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.
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 on August 26, 1998. It has also been designated an Important Bird Area (IBA), in both Bolivia and Peru, by BirdLife International because it supports significant populations of many bird species. Several threatened species such as the huge Titicaca water frog and the flightless Titicaca grebe are largely or entirely restricted to the lake.Fjeldså, J.; & Krabbe, N. (1990). Birds of the High Andes: A Manual to the Birds of the Temperate Zone of the Andes and Patagonia, South America.
In addition to the threatened Titicaca grebe, some of the birds associated with water at Titicaca are the white-tufted grebe, Puna ibis, Chilean flamingo, Andean gull, Andean lapwing, white-backed stilt, greater yellowlegs, snowy egret, black-crowned night-heron, Andean coot, common gallinule, plumbeous rail, various ducks, wren-like rushbird, many-colored rush-tyrant, and yellow-winged blackbird.
The Titicaca orestias has likely become extinct (last seen in 1938) due to competition and predation by the introduced rainbow trout and the silverside Odontesthes bonariensis.Parenti, Lynne R. (1984). A taxonomic revision of the Andean Killifish Genus Orestias (Cyprinodontiformes, Cyprinodontidae). Bulletin of the American Museum of Natural History 178: 107–214. In addition to the Titicaca orestias, native fish species in the lake's basin are other species of Orestias, and the catfish Trichomycterus dispar, T. rivulatus, and Astroblepus stuebeli (the last species not in the lake itself, but in associated ecosystems). The many Orestias species in Lake Titicaca differ significantly in both habitat preferenceLauzanne, L. (1992). Fish Fauna. pp. 405–448 in: Dejoux, C., eds. (1992). Lake Titicaca: a synthesis of limnological knowledge. and feeding behavior.Maldonado, E. E., Hubert, N. N., Sagnes, P. P., & De MÉrona, B. B. (2009). Morphology–diet relationships in four killifishes (Teleostei, Cyprinodontidae, Orestias) from Lake Titicaca. Journal of Fish Biology, 74(3), 502–520. About 90% of the fish species in the basin are endemic,Hales, J., and P. Petry (2013). Titicaca . Freshwater Ecoregions of the World. Retrieved 11 February 2013 including 23 species of Orestias that only are found in the lake.Vila, Morales, Scott, Poulin, Veliz, Harrod and Mendez (2013). Phylogenetic and phylogeographic analysis of the genus Orestias (Teleostei: Cyprinodontidae) in the southern Chilean Altiplano: the relevance of ancient and recent divergence processes in speciation. Journal of Fish Biology 82, 927–943.Titicaca is home to 24 described species of freshwater snails (15 endemics, including several tiny Heleobia spp.)Segers, H.; and Martens, K; editors (2005). The Diversity of Aquatic Ecosystems. p. 46. Developments in Hydrobiology. Aquatic Biodiversity. and less than half a dozen bivalves (all in family Sphaeriidae), but in general these are very poorly known and their taxonomy is in need of a review.Slugina, Z.V. (2006). Endemic Bivalvia in ancient lakes. Hydrobiologia 568(S): 213–217. The lake also has an endemic species flock of amphipods consisting of 11 Hyalella (an additional Titicaca Hyalella species is nonendemic).González, E.R.; and Watling, L. (2003). Two new species of Hyalella from Lake Titicaca, and redescriptions of four others in the genus (Crustacea: Amphipoda). Hydrobiologia 497(1-3): 181–204.