Wednesday, 31 December 2014

Sarmiento Lake and Amarga Lagoon

Sarmiento Lake is the largest lake in the Torres del Paine National Park, has an area of 86.2 km2 and maximum depth of 312m. It is considered a sub saline lake due to chemical composition of its water. Also it is the only lake in the park that is not fed directly from a glacier but by a number of streams that come from eutrophic lagoons which ones characterise by having a high concentration of organisms due to the presence of excessive nutrients.

    The lake waters are deep blue and is surrounded by the exotic Patagonian steep vegetation.

Toponym: the name, Sarmiento, is a tribute to Argentine Domingo Faustino Sarmiento, politician and writer who ruled Argentina between 1831 and 1874.
Earlier in 1831 and also in 1840, he lived in exile in Chile where he had a remarkable activity both in the field of education and journalism.

However Faustino Sarmiento was a very controversial man, he was accused of allowing Chile to take possession of Patagonian territory, ensuring that the Strait of Magellan belonged to Chile and was not worth doing military spending to defend the region.
Also he was one of the most criticised president in the history of Argentina mainly because of his racism against both Patagonian indigenous and gaucho.

The Amarga Lagoon is a shallow lagoon, maximum depth of 4m, is small: has an area of 318km2 and is located outside the boundaries of the park, about 5km from Sarmiento Lake.
The waters of the lake is lush green colour and flamencos use to come to its shore in search of food.

Toponym: the name, Amarga which means bitter, is related to the bitter taste of its water as it has a high salt index, PH 9.1 which form a halo of salt in almost all the edge. For reference: pure water has a PH 7 index and toilet soap 9-10.

The Sarmiento Lake and Amarga Lagoon belong to the same basin closed by moraines (moraine is a mass of rocks and other debris carried down and deposited by a glacier.) and both have closed water systems: receive their waters from some streams, but not having drainage emptying takes place by evaporation, when the water evaporates can not carry the minerals resulting in high- salt environment.

Along the shoreline of Sarmiento lake there can be observed a white halo, the thrombolites, a drop in lake level by 9m has resulted in the exposure of these carbonate structure reefs.

Thrombolites and stromatolites are structures generated in shallow and/or salty waters by cyanobacterias (Cianobae rivularia), also known as blue-green algaes because they are able to perform photosynthesis in which they absolve the carbon dioxide from the atmosphere with which to form the carbonate that precipitate to the ground combining with sedimentary material to build these structures.

The word thrombolite or thrombolith derived from the same root as thrombosis which means clot, as thrombolites have a clotted structure, clumpy structure.

And the word stromatolite or stromatolith from the Greek word stroma that means bed, as stromatolites have a laminated structure, finely layered structure.

Scientists do not know whether stromatolites became thrombolites or thrombolites arose independently.

Biologists generally believe that cyanobacterias played a key role in increasing the amount of oxygen in the earth's atmosphere as these organisms are very old, some fossils date back more than 3.5 billion years, one of the oldest things in the fossil record. However is belied that the formation of the lake took place about 10.000 years ago so these thrombolites as well.

Thrombolites and stromatolites are true living fossils, in fact, are few places in the world that these living organisms can be studied and observed. However there is no doubt that it is the scenic beauty of Torres del Paine National Park that attracts thousands of visitors each year. From the viewpoints of Sarmiento Lake and Amarga Lagoon one can have a magnificent panoramic of the Paine Massif and observe the amazing condors flying around.

Tourist information:  Punta Arenas:





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