Rio Tinto (river)

Río Tinto
River
Rio Tinto
Country Spain
Region Andalusia
Source Sierra Morena
Mouth
 - location Gulf of Cádiz
 - coordinates 37°12′36″N 6°56′17″W / 37.21°N 6.938°W / 37.21; -6.938Coordinates: 37°12′36″N 6°56′17″W / 37.21°N 6.938°W / 37.21; -6.938
Length 100 km (62 mi)
Location of the mouth within Andalusia

The Río Tinto (Spanish pronunciation: [ˈri.o ˈtinto], red river) is a river in southwestern Spain that rises in the Sierra Morena mountains of Andalusia. It flows generally south-southwest, reaching the Gulf of Cádiz at Huelva. The Rio Tinto River has a unique red and orange colour. The colour is derived from the chemical makeup of the river. The river is extremely acidic and contains very high levels of iron.[1] The combination of the acid water, heavy metals and high levels of iron give the river its unique colour.[2] The River maintains its colour for an approximate length of 50 kilometres.[3] After the 50 kilometre mark, the chemistry that makes the Rio Tinto river so unique appears to slowly decline, as with the odd colouring. The location where the chemistry of the river is altered is near a town called Niebla.[4] The river's chemistry begins to significantly change following the town of Niebla owing to the fact that the Rio Tinto blends itself with other streams that are connected to the Atlantic Ocean.[4] The length of the river is around 100 kilometres long and is located within the Iberian Pyrite Belt.[5] This area has large amounts of ore and sulfide deposits. This specific region in Spain has seen many years of mining. The mining projects focus primarily on the river but ore deposits have also been found 20 kilometres from the shoreline.[6] Rio Tinto has been the root of approximately 5000 years of ore extraction.[7] Due to all of the mining activity in the area, the topography has been vastly modified.[7]

Rio Tinto River

Since ancient times, a site along the river has been mined for copper, silver, gold, and other minerals.[8] In approximately 3000 BC, Iberians and Tartessians began mining the site, followed by the Phoenicians, Greeks, Romans, Visigoths, and Moors. After a period of abandonment, the mines were rediscovered in 1556 and the Spanish government began operating them once again in 1724.[8] As a possible result of the mining, the Río Tinto is notable for being very acidic (pH 2) and its deep reddish hue is due to iron dissolved in the water. Acid mine drainage from the mines leads to severe environmental problems due to the heavy metal concentrations in the river. In 1873, the Rio Tinto Company was formed to operate the mines; by the end of the 20th century it had become one of the world's largest multinational mining companies, although it no longer controls the Río Tinto mines; these are now owned by EMED Mining.

The Rio Tinto River is extremely acidic which is due to the acid drainage from previous mining history as well as natural acid rock drainage in the area. It is not clear how much acid drainage has come from natural processes and how much has come from mining. This fact has yet to be discovered. There are severe environmental concerns over the pollution in the river. The pollution plays a key role in the river's unique colour. Its environmental concerns are partially due to the river's' very high levels of metal and hydrogen ions.[9] Although certain forms of life do thrive in these extreme environmental conditions. The Rio Tinto River is habitat to certain forms of bacteria, algae and heterotrophs.[10] More specifically eukaryotes and chemolithotrophic bacteria, as well as other microorganisms.[10]

History

The Rio Tinto in 2006

The ore body was deposited in the Carboniferous (300–350 Ma) by hydrothermal activities on the sea floor. The river area has a history of mining activity since the Tartessans and the Iberians started mining in 3000 BC. The mining continued over the Phoenician era and under the Roman Empire until the second part of the 15th century: primarily for copper but also for iron and manganese. In the nineteenth century the mining operation started on a large scale mining companies from the United Kingdom. After the peak of production in 1930, production declined and ended in 1986 for copper mining and in 1996 for silver and gold mining.[11] The mine closed in 2001. Increased copper prices in the 2010s led to efforts by EMED Mining to reopen the mine, but difficulties in acquiring all property rights necessary, environmental concerns, and obtaining regulatory approval delayed reopening. The mine, which employed as many as 20,000 in the past, would employ 350 people during its startup phase. The firm acquired US$250 million in financing for the project. Environmental concerns are centered on disused water reservoirs which might not be able to withstand the stress of renewed waste inputs.[12]

Astrobiology

This river has gained recent scientific interest due to the presence of extremophile anaerobic bacteria that dwell in the water. (Similar extremophile archaea are Archaeal Richmond Mine Acidophilic Nanoorganisms.) The subsurface rocks on the river bed contain iron and sulfide minerals on which the bacteria feed.[13][14][15] The extreme conditions in the river may be analogous to other locations in the solar system thought to contain liquid water, such as subterranean Mars. NASA scientists have also directly compared the chemistry of the water in which the rocks of Meridiani Planum were deposited in the past with the Río Tinto.[16] Likewise Jupiter's moon Europa is theorized to contain an acidic ocean of water underneath its ice surface. Thus the river is of interest to astrobiologists.

Based partially on research done near the Río Tinto, two NASA scientists were reported saying on February 2005 that they had found strong evidence of present life on Mars.[17] NASA officials denied the scientists’ claims shortly after they were released,[18] and one of the scientists, Carol Stoker, said she was misquoted at the party in which the initial statement was made.[19]

Anaerobic sediments

Due to the extreme conditions of the river, there is very little in the way of life, with the exception of small amounts of microorganisms, including algae. The presence of anaerobic bacteria in the form of sediments is thought to contribute to the river's famously low pH. The waters from the Rio Tinto, high in metal sulfides, provide an ideal environment for chemolithoautotrophic microorganisms, with the sulfides acting as a food source. The product of metal sulfide metabolism through oxidization is ferric iron and secretion of acidic liquid. The continuation of this process for an extended period of time is thought to be responsible for keeping the river's pH between 2 and 2.5 in most areas. Even in the extremely acidic water, both red and green algae have been observed to grow and survive in relatively high concentrations[20]. Despite algae levels in the Rio Tinto accounting for over half of the total biomass in the river, algae is understood to have minimal effects on the characteristics of the complex ecosystem[21]. A common belief of the Rio Tinto is that it became acidic and developed its unique water chemistry as a result of thousands of years of mining, including intensive mining during the twentieth century. This has in fact proven to be false, through the discovery of multiple oxide terraces at up to 60 meters above the current water level, and as far away as 20 kilometers from the current river's path. Oxide terraces prove that the unusual ecosystem is a natural phenomenon and has been present since before human involvement in the region by showing historical proof of the similar water chemistry[22].

See also

References

  1. ↑ Amaral Zettler, Linda A.; Messerli, Mark A.; Laatsch, Abby D.; Smith, Peter J. S.; Sogin, Mitchell L. (2003-04-01). "From Genes to Genomes: Beyond Biodiversity in Spain's Rio Tinto". The Biological Bulletin. 204 (2): 205–209. doi:10.2307/1543560. ISSN 0006-3185.
  2. ↑ Amaral Zettler, Linda A.; Messerli, Mark A.; Laatsch, Abby D.; Smith, Peter J. S.; Sogin, Mitchell L. (2003-04-01). "From Genes to Genomes: Beyond Biodiversity in Spain's Rio Tinto". The Biological Bulletin. 204 (2): 205–209. doi:10.2307/1543560. ISSN 0006-3185.
  3. ↑ Fernández-Remolar, David C.; Morris, Richard V.; Gruener, John E.; Amils, Ricardo; Knoll, Andrew H. "The Río Tinto Basin, Spain: Mineralogy, sedimentary geobiology, and implications for interpretation of outcrop rocks at Meridiani Planum, Mars". Earth and Planetary Science Letters. 240 (1): 149–167. Bibcode:2005E&PSL.240..149F. doi:10.1016/j.epsl.2005.09.043.
  4. 1 2 Fernández-Remolar, David C.; Morris, Richard V.; Gruener, John E.; Amils, Ricardo; Knoll, Andrew H. "The Río Tinto Basin, Spain: Mineralogy, sedimentary geobiology, and implications for interpretation of outcrop rocks at Meridiani Planum, Mars". Earth and Planetary Science Letters. 240 (1): 149–167. Bibcode:2005E&PSL.240..149F. doi:10.1016/j.epsl.2005.09.043.
  5. ↑ Amaral Zettler, Linda A.; Messerli, Mark A.; Laatsch, Abby D.; Smith, Peter J. S.; Sogin, Mitchell L. (2003-04-01). "From Genes to Genomes: Beyond Biodiversity in Spain's Rio Tinto". The Biological Bulletin. 204 (2): 205–209. doi:10.2307/1543560. ISSN 0006-3185.
  6. ↑ Fernández-Remolar, David C.; Morris, Richard V.; Gruener, John E.; Amils, Ricardo; Knoll, Andrew H. "The Río Tinto Basin, Spain: Mineralogy, sedimentary geobiology, and implications for interpretation of outcrop rocks at Meridiani Planum, Mars". Earth and Planetary Science Letters. 240 (1): 149–167. Bibcode:2005E&PSL.240..149F. doi:10.1016/j.epsl.2005.09.043.
  7. 1 2 Fernández-Remolar, David C.; Morris, Richard V.; Gruener, John E.; Amils, Ricardo; Knoll, Andrew H. "The Río Tinto Basin, Spain: Mineralogy, sedimentary geobiology, and implications for interpretation of outcrop rocks at Meridiani Planum, Mars". Earth and Planetary Science Letters. 240 (1): 149–167. Bibcode:2005E&PSL.240..149F. doi:10.1016/j.epsl.2005.09.043.
  8. 1 2 Bordenstein, Sarah. "Rio Tinto, Spain". Science Education Resource Center. Carleton College. Retrieved March 3, 2009.
  9. ↑ Fernández-Remolar, David C.; Morris, Richard V.; Gruener, John E.; Amils, Ricardo; Knoll, Andrew H. "The Río Tinto Basin, Spain: Mineralogy, sedimentary geobiology, and implications for interpretation of outcrop rocks at Meridiani Planum, Mars". Earth and Planetary Science Letters. 240 (1): 149–167. Bibcode:2005E&PSL.240..149F. doi:10.1016/j.epsl.2005.09.043.
  10. 1 2 Fernández-Remolar, David C.; Morris, Richard V.; Gruener, John E.; Amils, Ricardo; Knoll, Andrew H. "The Río Tinto Basin, Spain: Mineralogy, sedimentary geobiology, and implications for interpretation of outcrop rocks at Meridiani Planum, Mars". Earth and Planetary Science Letters. 240 (1): 149–167. Bibcode:2005E&PSL.240..149F. doi:10.1016/j.epsl.2005.09.043.
  11. ↑ Davis, R. A., Jr.; Welty, A. T.; Borrego, J.; Morales, J. A.; Pendon, J. G.; Ryan, J. G. (2000). "Rio Tinto estuary (Spain): 5000 years of pollution". Environmental Geology. 39 (10): 1107–1116. doi:10.1007/s002549900096.
  12. ↑ Minder, Raphael (April 12, 2012). "In Struggling Spanish Town, Hopes of Reopening Mine Are Delayed". The New York Times. Retrieved April 13, 2012.
  13. ↑ Fernández Remolar, D. C.; Morris, R. V.; Gruener, J. E.; Amils, R.; Knoll, A. H. (2005). "The Rio Tinto basin, Spain: Mineralogy, sedimentary geobiology, and implications for interpretation of outcrop rocks at Meridiani Planum, Mars". Earth and Planetary Science Letters. 240 (1): 149–167. Bibcode:2005E&PSL.240..149F. doi:10.1016/j.epsl.2005.09.043.
  14. ↑ Fernández Remolar, D. C.; Rodríguez, N.; Gómez, F.; Amils, R. (2003). "Geological record of an acidic environment driven by iron hydrochemistry: The Tinto River system". Journal of Geophysical Research: Planets. 108 (E7): 5080. Bibcode:2003JGRE..108.5080F. doi:10.1029/2002JE001918.
  15. ↑ Sánchez Andrea, I; Rodríguez, N; Amalis, R; Sans, J. L. (2011). "Microbial diversity in anaerobic sediments at Rio Tinto, a naturally acidic environment with a high heavy metal content". Applied and Environmental Microbiology. 77 (17): 6085–6093. doi:10.1128/AEM.00654-11. PMC 3165421.
  16. ↑ Guy Webster (2005-11-29). "News | NASA Rover Helps Reveal Possible Secrets of Martian Life". Jpl.nasa.gov. Retrieved 2017-01-16.
  17. ↑ Berger, Brian (2005-02-16). "Exclusive: NASA Researchers Claim Evidence of Present Life on Mars". Space.com. Retrieved 2017-01-16.
  18. ↑ "NASA denies Mars life reports". Spacetoday.net. 2005-02-19. Retrieved 2017-01-16.
  19. ↑ "Scientist at center of Mars flap speaks out - Technology & science - Space". NBC News. 2005-03-22. Retrieved 2017-01-16.
  20. ↑ Sanz, José L.; Rodríguez, Nuria; Díaz, Emiliano E.; Amils, Ricardo (2011-08-01). "Methanogenesis in the sediments of Rio Tinto, an extreme acidic river". Environmental Microbiology. 13 (8): 2336–2341. doi:10.1111/j.1462-2920.2011.02504.x. ISSN 1462-2920.
  21. ↑ Fernández-Remolar, David C.; Morris, Richard V.; Gruener, John E.; Amils, Ricardo; Knoll, Andrew H. "The Río Tinto Basin, Spain: Mineralogy, sedimentary geobiology, and implications for interpretation of outcrop rocks at Meridiani Planum, Mars". Earth and Planetary Science Letters. 240 (1): 149–167. Bibcode:2005E&PSL.240..149F. doi:10.1016/j.epsl.2005.09.043.
  22. ↑ Fernández-Remolar, David C.; Morris, Richard V.; Gruener, John E.; Amils, Ricardo; Knoll, Andrew H. "The Río Tinto Basin, Spain: Mineralogy, sedimentary geobiology, and implications for interpretation of outcrop rocks at Meridiani Planum, Mars". Earth and Planetary Science Letters. 240 (1): 149–167. Bibcode:2005E&PSL.240..149F. doi:10.1016/j.epsl.2005.09.043.
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