__NOTOC__

Lake Poopó ( es, Lago Poopó ) was a large

saline lake A salt lake or saline lake is a landlocked body of water that has a concentration of salt (chemistry), salts (typically sodium chloride) and other dissolved minerals significantly higher than most lakes (often defined as at least three grams of ...

in a shallow depression in the Altiplano Mountains in

Oruro Department Oruro (; Quechua: ''Uru Uru''; Aymara: ''Ururu'') is a department of Bolivia, with an area of . Its capital is the city of Oruro. According to the 2012 census, the Oruro department had a population of 494,178. Provinces of Oruro The departme ...

Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square p ...

, at an

altitude Altitude or height (also sometimes known as depth) is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The exact definition and reference datum varies according to the context ...

of approximately . Because the lake was long and wide (), it made up the eastern half of the department, known as a mining region in southwest

. The permanent part of the lake body covered approximately and it was the second-largest lake in the country. The lake received most of its water from the Desaguadero River, which flows from

Lake Titicaca 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, ...

at the north end of the Altiplano. Since the lake lacked any major outlet and had a mean depth of less than , the surface area differed greatly seasonally. In 2002 the lake was designated as a site for conservation under the

Ramsar Convention The Ramsar Convention on Wetlands of International Importance Especially as Waterfowl Habitat is an international treaty for the conservation and sustainable use of Ramsar sites (wetlands). It is also known as the Convention on Wetlands. It i ...

. By December 2015, the lake had completely dried up, leaving only a few marshy areas. Although the lake has dried up completely twice in the past, it does not appear that it will recover this time. Suggested causes of the decline are the melting of the Andes glaciers and loss of their waters, because of a drought due to climate change, as well as continued diversion of water for mining and agriculture.

Archaeological evidence

Archaeological investigations conducted by the San Andrés University of La Paz, Bolivia, shows the influence of the

Wankarani culture The Wankarani culture was a formative stage culture that existed from approximately 1500 BCE to 400 CE on the altiplano highlands of Bolivia's Oruro Department to the north and northeast of Lake Poopo. It is the earliest known sedentary culture ...

in the Poopó area. Complex central

urban area An urban area, built-up area or urban agglomeration is a human settlement with a high population density and infrastructure of built environment. Urban areas are created through urbanization and are categorized by urban morphology as cities ...

s, such as villages and towns, were developed that expanded into the Poopó basin during the Late Formative period, (200 BC – 200 AD), probably in conjunction with changing patterns of agriculture. Herders and the life style of

llama The llama (; ) (''Lama glama'') is a domesticated South American camelid, widely used as a meat and pack animal by Andean cultures since the Pre-Columbian era. Llamas are social animals and live with others as a herd. Their wool is soft ...

caravan merchants coexisted with more sedentary farmers in a harmonious system of exchange of goods and services. Other investigators examining the following period, the Early Regional Developments ( 300 – 900 AD), have concluded that the size of the inhabited areas increased. The South Poopó inhabitants developed a unique style of ceramics style with triangular spirals. The east portion of the lake has evidence of an important

Tiwanaku Tiwanaku ( es, Tiahuanaco or ) is a Pre-Columbian archaeological site in western Bolivia near Lake Titicaca, about 70 kilometers from La Paz, and it is one of the largest sites in South America. Surface remains currently cover around 4 square kilo ...

enclave An enclave is a territory (or a small territory apart of a larger one) that is entirely surrounded by the territory of one other state or entity. Enclaves may also exist within territorial waters. ''Enclave'' is sometimes used improperly to deno ...

, with ceramic styles from the core Titicaca area and surrounding styles, demonstrating the interactions between different peoples in the area.

Lake dynamics

The main inlet of Lake Poopó (roughly 92% of the water) comes from the Desaguadero River, which enters the lake at the north end. It flows south from

. There are numerous smaller inlets along the eastern shore of the lake, many of which are dry most of the year. At times of very high water levels, Poopó is connected to the salt desert

Salar de Coipasa __NOTOC__ Lago Coipasa or Salar de Coipasa is a lake in Sabaya Province, Oruro Department, Bolivia. At an elevation of 3657 m, its surface area is 806 km². It is on the western part of Altiplano, 20 km north of Salar de Uyuni and south ...

in the west. A minor outlet leads to Salar de Uyuni in the far south of the Altiplano, but as the lake lacks any major outlet, it is classified as an

endorheic basin An endorheic basin (; also spelled endoreic basin or endorreic basin) is a drainage basin that normally retains water and allows no outflow to other external bodies of water, such as rivers or oceans, but drainage converges instead into lakes ...

When the water level of Lake Titicaca is below , the flow of Desaguadero River is so low it can no longer compensate for the massive water losses due to evaporation from the surface of Lake Poopó. At this point, the lake volume begins to decrease. At its maximum in 1986, the lake had an

area Area is the quantity that expresses the extent of a region on the plane or on a curved surface. The area of a plane region or ''plane area'' refers to the area of a shape or planar lamina, while '' surface area'' refers to the area of an ope ...

of . During the years that followed, the surface area steadily decreased until 1994, when the lake disappeared completely. The time period between 1975 and 1992 is the longest period in recent times when the lake had a continuous water body. Renewed rainfalls in the mid-1990s revitalized the lake again. Action has been taken in order to make the area ecologically sustainable again, with the help of funding from the

European Union The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...

. But the efforts have been unable to offset other changes: since 1995 regional temperatures have risen and consequently tripled the evaporation rates. In addition, water was drawn off for mining and irrigation, compounding the problems. On 20 January 2016 the area was declared a disaster zone by the Bolivian government.

Salinity and geology

The water of Lake Poopó is highly saline. The salinity is a result of the endorheic nature of the hydrological system on the Altiplano, which allows all weathered ions to remain in the system. The salinity of Lake Poopó is further increased by the

arid A region is arid when it severely lacks available water, to the extent of hindering or preventing the growth and development of plant and animal life. Regions with arid climates tend to lack vegetation and are called xeric or desertic. Most ...

climate Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologi ...

and the high evaporation from the lake surface. In the northern end of Lake Poopó, dilution of the salinity occurs due to freshwater flow from the Desaguadero River. The salt

gradient In vector calculus, the gradient of a scalar-valued differentiable function of several variables is the vector field (or vector-valued function) \nabla f whose value at a point p is the "direction and rate of fastest increase". If the gr ...

of the water increases towards the south. The salinity varies with water volume. During October and November 2006, the salinity in the north end of the lake varied between

brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estu ...

and saline (15–30,000 mg/L). In the south end of the lake the water was classified as a brine (105,000–125,000 mg/L). The water type is a 4–2 Na-(Mg)-Cl-(SO₄). Geological sources of

sodium chloride Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g ...

(NaCl), such as

halite Halite (), commonly known as rock salt, is a type of salt, the mineral (natural) form of sodium chloride ( Na Cl). Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, p ...

and

feldspars Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feldsp ...

, are present in the drainage area. These could also contribute to the salinity of Lake Poopó. The lake body is situated on top of

Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configura ...

deposits, consisting mainly of unconsolidated material. These sediments are the remains of extensive

prehistoric Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of ...

lakes, which covered the Altiplano during at least five

glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate be ...

periods.

Mining and heavy metals

There is a long tradition of

mining Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic ...

in the Poopó Basin. Extraction of metals was ordered in the 13th century to support the

Inca The Inca Empire (also known as the Incan Empire and the Inka Empire), called ''Tawantinsuyu'' by its subjects, (Quechua for the "Realm of the Four Parts", "four parts together" ) was the largest empire in pre-Columbian America. The admin ...

army. After Spanish colonization in the 16th century, the mining operations increased in scale. At this point the region became known as one of the mining centres of Bolivia. footprint

The mining districts are situated at the foothills of the Cordillera Oriental along the eastern border of the Poopó basin. The most important minerals to the economy are

silver Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical ...

and

tin Tin is a chemical element with the symbol Sn (from la, stannum) and atomic number 50. Tin is a silvery-coloured metal. Tin is soft enough to be cut with little force and a bar of tin can be bent by hand with little effort. When bent, t ...

. Studies have shown elevated concentrations of heavy metals in surface and ground waters of the Poopó basin. These metals are naturally present in the bedrock, from which they are released through

weathering Weathering is the deterioration of rocks, soils and minerals as well as wood and artificial materials through contact with water, atmospheric gases, and biological organisms. Weathering occurs ''in situ'' (on site, with little or no movement), ...

processes. The mining activities in the area further contributes to the heavy metal

pollution Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the ...

. Acid leaching from mines and mechanical processing of

ore Ore is natural rock or sediment that contains one or more valuable minerals, typically containing metals, that can be mined, treated and sold at a profit.Encyclopædia Britannica. "Ore". Encyclopædia Britannica Online. Retrieved 7 Apr ...

speed up the process. The major part of the heavy metals transported to Lake Poopó seem to be immobilized in the bottom sediments. But concentrations of

arsenic Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, ...

lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...

, and

cadmium Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it demonstrates oxidation state +2 in most of ...

in the lake water exceed Bolivian and

World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of h ...

guideline values for drinking water.

Flora and fauna

There are only three fish species in the system: the native pupfish ''

Orestias Orestias ( el, Ὀρεστιάς) was an ancient Greek settlement next to the Maritsa (or Evros) river, near or at the site of present-day Edirne, and close to the current border between Turkey and Greece. Legends claim that Orestias was founded ...

agassizii'' and catfish '' Trichomycterus rivulatus'', and the introduced silverside ''

Odontesthes bonariensis ''Odontesthes bonariensis'' is a species of Neotropical silverside, an euryhaline fish native to fresh, brackish and salt water in south-central and southeastern South America, but also introduced elsewhere. It is often known by the common nam ...

''. The lake had a relatively large fish population, but by 2017 pollution and the near-complete reduction of water had all but decimated the locally important fishing industry. The aquatic bird life was very diverse, with a total of 34 species. Most famous are the three species of

flamingo Flamingos or flamingoes are a type of wading bird in the family Phoenicopteridae, which is the only extant family in the order Phoenicopteriformes. There are four flamingo species distributed throughout the Americas (including the Caribbea ...

(

Andean The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S l ...

, James's and Chilean), which mainly lived in the shallow lagoons in the northern and eastern parts of the lake. An inventory of the bird population, made in 2000 in cooperation with BirdLife International, identified 6

threatened species Threatened species are any species (including animals, plants and fungi) which are vulnerable to endangerment in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of '' critical depen ...

and others that are

near-threatened A near-threatened species is a species which has been categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature as that may be vulnerable to endangerment in the near future, but it does not currently qualify f ...

. Among these are the Andean flamingo and the

Andean condor The Andean condor (''Vultur gryphus'') is a giant South American Cathartid vulture and is the only member of the genus ''Vultur''. Found in the Andes mountains and adjacent Pacific coasts of western South America, the Andean condor is the larg ...

. A total of 17

higher plant Vascular plants (), also called tracheophytes () or collectively Tracheophyta (), form a large group of land plants ( accepted known species) that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They a ...

s and 3 species of algae were identified in and around Lake Poopó. Due to the constant drought and flooding, the

littoral zone The littoral zone or nearshore is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely inundated), to coastal a ...

experiences great disturbances. As a result, there was hardly any vegetation to be found on the shores of the lake.

Effects of the loss of the lake

The sparse communities nearby have suffered culturally and financially due to the local economy being dependent on lake fishing. Moreover, many bird species native to Bolivia and internationally have been affected due to loss of food, and an annual migration area.

References

* Drever, James I: ''The Geochemistry of Natural Waters'', 3rd edition, Prentice Hall, 1997. * Montes de Oca; ''Geografia y Recursos Naturales de Bolivia'', 3rd Edition, EDOBOL, La Paz, 1997. * Rocha, O.O. (editor): "Diagóstico de los recursos naturales y culturales de los lagos Poopó y Uru Uru, Oruro – Bolivia". Convención Ramsar, WCS/Bolivia, La Paz, 2002. * Troëng, B., Riera-Kilibarda C. ''Mapas temáticos de recursos minerales de Bolivia'', Boletin del Servicio geológico de Bolivia N 7, La Paz, 1996.

External links

Master thesis about heavy metals in the rivers of the Poopó basinMaster thesis about heavy metals in Lake PoopóSatellite images and information from NASA about Lake PoopóLake Titicaca, Lake Poopó, and Salar de Uyuni, BoliviaBolivia DrainageBolivia's second-largest lake dries up and may be gone forever, lost to climate change
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The Guardian ''The Guardian'' is a British daily newspaper. It was founded in 1821 as ''The Manchester Guardian'', and changed its name in 1959. Along with its sister papers ''The Observer'' and ''The Guardian Weekly'', ''The Guardian'' is part of the Gu ...

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{{DEFAULTSORT:Poopo Lakes of Oruro Department Endorheic lakes of South America Saline lakes of South America Archaeological cultures of South America Ramsar sites in Bolivia Former lakes of South America Altiplano