Loki's Castle (hydrothermal field)

Loki's Castle is a field of five active hydrothermal vents in the mid-Atlantic ocean, located at 73 degrees north on the Mid-Atlantic Ridge between Greenland and Norway [cite web |url=http://www.sciencedaily.com/releases/2008/07/080724153941.htm |title=Scientists Break Record By Finding Northernmost Hydrothermal Vent Field |accessdate=2008-07-25 |publisher="Science Daily" |date=2008-07-24 ] at a depth of 2,352.18 metres. [cite web |url=http://www.eurekalert.org/multimedia/pub/9252.php?from=118768 |title=Arctic Circle Vent |accessdate=2008-07-25 |publisher=University of Washington |date=2008-07-24 ] They were discovered in mid-July 2008 and are the most northerly Black Smokers which have been located. [cite web |url=http://www.livescience.com/environment/080724-black-smokers.html |title=Boiling Hot Water Found in Frigid Arctic Sea |accessdate=2008-07-25 |publisher=livescience.com |date=2008-07-24 ] They are of geological interest as they are in a more stable area of the earth's crust, where tectonic forces are less and consequently fields of hydrothermal vents are relatively less common.

The vents were discovered by a 25-person multinational scientific expedition of the University of Bergen, Norway, more than convert|120|mi|km north of what were previously the most northern vents which were discovered in 2005. The 2005 and 2008 expeditions were both led by geologist Rolf Pedersen of the university’s Centre for Geobiology, aboard the new Research Vessel "G.O. Sars" [cite web |url=http://www.sciencedaily.com/releases/2008/07/080724153941.htm |title=Scientists Break Record By Finding Northernmost Hydrothermal Vent Field |accessdate=2008-07-25 |publisher="Science Daily" |date=2008-07-24 ] (named after the Norwegian marine biologist Georg Ossian Sars [cite web |url=http://www.uib.no/forskningsfartoy/english/background/index.html |title=Background about the G.O. Sars |accessdate=2008-07-25 |publisher=University of Bergen] and launched in May 2003 [cite web |url=http://www.imr.no/english/about_imr/vessels/g.o._sars |title=G.O. Sars |accessdate=2008-07-25 |publisher=Norwegian Institute of Marine Research] ). The vents were located using a remotely controlled undersea vehicle. [cite web |url=http://www.sciencedaily.com/releases/2008/07/080724153941.htm |title=Scientists Break Record By Finding Northernmost Hydrothermal Vent Field |accessdate=2008-07-25 |publisher="Science Daily" |date=2008-07-24 ]

The five active chimneys of Loki's Castle are venting water as hot as 300 °C (570 °F) and sit on a vast mound of sulphide minerals which is about 251 metres (825 ft) in diameter at its base, and some 91 metres (300 ft) across its top. [cite web |url=http://www.sciencedaily.com/releases/2008/07/080724153941.htm |title=Scientists Break Record By Finding Northernmost Hydrothermal Vent Field |accessdate=2008-07-25 |publisher="Science Daily" |date=2008-07-24 ] A member of the 2008 Expedition, oceanographer Marvin Lilley of the University of Washington, has speculated that this may be the largest such deposit ever seen on the sea floor. [cite web |url=http://www.sciencedaily.com/releases/2008/07/080724153941.htm |title=Scientists Break Record By Finding Northernmost Hydrothermal Vent Field |accessdate=2008-07-25 |publisher="Science Daily" |date=2008-07-24 ] The active chimneys are mostly black in colour, but are covered with mats of white bacteria which are living on minerals and materials emitted by the vents. The older chimneys are a mottled red colour, due to the presence of deposits of oxidised iron.

The vent field was given the name Loki's Castle as its shape reminded its discoverers of a fantasy castle. The reference to the ancient Norse god Loki was explained by a University of Bergen press release that said it "was an appropriate name for a field that was so difficult to locate". [cite web |url=http://www.sciencedaily.com/releases/2008/07/080724153941.htm |title=Scientists Break Record By Finding Northernmost Hydrothermal Vent Field |accessdate=2008-07-25 |publisher="Science Daily" |date=2008-07-24 ]

Preliminary observations have shown the warm area around the Loki's Castle vents to be alive with diverse and apparently unique microorganisms and vent fauna, unlike vent communities observed elsewhere. [cite web |url=http://www.sciencedaily.com/releases/2008/07/080724153941.htm |title=Scientists Break Record By Finding Northernmost Hydrothermal Vent Field |accessdate=2008-07-25 |publisher="Science Daily" |date=2008-07-24 ]

References

External links

*cite web |url=http://www.sciencedaily.com/releases/2008/07/080724153941.htm |title=Scientists Break Record By Finding Northernmost Hydrothermal Vent Field |accessdate=2008-07-25 |publisher="Science Daily" |date=2008-07-24
*Sandra Hines, " [http://www.eurekalert.org/pub_releases/2008-07/uow-sbr072408.php Scientists break record by finding northernmost hydrothermal vent field] ", University of Washington Press Release, 24 July 2008.
* [http://www.geobio.uib.no/View.aspx?mid=1062&itemid=90&pageid=1093&moduledefid=71 2008 University of Bergen Expedition Journal for Day 17 (15 July 2008)] , describing the moment of discovery.
* [http://www.geobio.uib.no/Default.aspx?pageid=1092 Photographs of the 2008 University of Bergen Expedition team members]
* [http://www.geobio.uib.no/Default.aspx?pageid=792 Background information about hydrothermal fields] (provided by the Centre for Geobiology, University of Bergen)