Don Juan Pond

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Don Juan Pond
DonJuanSTILL.0660 web.jpg
Satellite image
Location East Antarctica
Coordinates 77°33′52″S 161°10′20″E / 77.56444°S 161.17222°E / -77.56444; 161.17222Coordinates: 77°33′52″S 161°10′20″E / 77.56444°S 161.17222°E / -77.56444; 161.17222
Type hypersaline lake
Basin countries (Antarctica)
Max. length 300 m (980 ft)
Max. width 100 m (330 ft)
Surface area 0.03 km2 (0.012 sq mi)
Average depth 16 in (410 mm)
Max. depth 3 ft (0.91 m)
Water volume 3,000 m3 (110,000 cu ft)
Surface elevation 116 m (381 ft)
Frozen no
Islands none
Settlements Vanda Station
(14 km to the east)

Don Juan Pond is a small and very shallow hypersaline lake in the western end of Wright Valley (South Fork), Victoria Land, Antarctica, 9 kilometres (5.6 mi) west from Lake Vanda. It is wedged between the Asgard Range to the south and the Dais Range to the north. On the west end is a small tributary and a rock glacier. With a salinity level of over 47%, Don Juan Pond is the saltiest of the Antarctic lakes[1][2] This salinity allows the pond to remain liquid even at temperatures as low as −50 °C (−58 °F) due to the interference of salts with the bonding of water molecules.

Don Juan Pond was discovered in 1961 by George H. Meyer. It was named for two helicopter pilots, Lt. Don Roe and Lt. John Hickey, who piloted the helicopter involved with the first field party investigating the pond.[2]

Salinity[edit]

Don Juan Pond is located near lower left (southwest) corner of map

Don Juan Pond is a shallow, flat-bottom, hyper-saline pond. It has the highest total dissolved solids on record, with greater salinity than the Dead Sea or Lake Assal (Djibouti) (the same is true for Lake Vanda and perhaps other lakes in the McMurdo Dry Valleys). Salinity varies over time from 200 to 474 g/L, dominated by calcium chloride, and is over 18 times the ocean's salinity and 1.3 times that of the Dead Sea. It is the only Antarctic hypersaline lake that almost never freezes. It has been described as a groundwater discharge zone.[3] The area around Don Juan Pond is covered with sodium chloride and calcium chloride salts that have precipitated as the water evaporated.[4][5]

The area and volume of Don Juan Pond vary over time. According to the USGS topographical map published in 1977, the area was approximately 0.25 km2 (62 acres). However, in recent years the pond has shrunk considerably. The maximum depth in 1993–1994 was described as "a foot deep" (30 cm). In January 1997, it was approximately 10 centimetres (3.9 in) deep; [3] in December 1998 the pond was almost dry everywhere except for an area of a few tens of square metres. Most of the remaining water was in depressions around large boulders in the pond.[6]

Life[edit]

Studies of lifeforms in the hypersaline (and/or brine) water of Don Juan Pond have been equivocal.[7][8]

Literature[edit]

  • Yamagata, N.; T. Torii, S. Murata. "Report of the Japanese summer parties in Dry Valleys, Victoria Land, 1963–65; V – Chemical composition of lake waters". Antarctic Record. 29: 53–75. 

References[edit]

  1. ^ Hammer, U.T. (1986). Saline Lake Ecosystems of the World. Springer. p. 109. ISBN 9789061935353. Retrieved 27 March 2018. 
  2. ^ a b Vanjo, Grobljar. "Don Juan Pond and Lake Vanda". pbase.com. Retrieved April 7, 2017. 
  3. ^ a b Salty Antarctic pond could be a replica of Mars' water. Astrobiology Magazine. 23 November 2017.
  4. ^ Hammer, U.T. (1986). Saline Lake Ecosystems of the World. Springer. p. 109. ISBN 9789061935353. Retrieved 27 March 2018. 
  5. ^ Oren, Aharon (2007). "Salts and Brines". In Whitton, Brian A.; Potts, Malcolm. The Ecology of Cyanobacteria: Their Diversity in Time and Space. Springer. p. 287. ISBN 9780306468551. Retrieved 27 March 2018. 
  6. ^ "Lake Levels" (csv). McMurdo Dry Valleys Long-Term Ecological Research. Retrieved 28 March 2018. 
  7. ^ Siegel, B.Z.; McMurty, G.; Siegel, S.M.; Chen, J.; Larock, P. (30 August 1979). "Life in the calcium chloride environment of Don Juan Pond, Antarctica". Nature. 280: 828–829. doi:10.1038/280828a0. Retrieved 30 September 2015. 
  8. ^ Chang, Kenneth (28 September 2015). "NASA Says Signs of Liquid Water Flowing on Mars". New York Times. Retrieved 28 September 2015. 

External links[edit]