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ocean bank

{{Short description|Part of the sea which is shallow compared to its surrounding area}}

{{For|the American financial institution|Ocean Bank}}

File:GulfofMaine.jpg in the Gulf of Maine is a large elevated area of the sea floor, shown in this map as the light blue region at the bottom centre.]]

{{Ocean habitat topics}}

An ocean bank, sometimes referred to as a fishing bank or simply bank, is a part of the seabed that is shallow compared to its surrounding area, such as a shoal or the top of an underwater hill. Somewhat like continental slopes, ocean bank slopes can upwell as tidal and other flows intercept them, sometimes resulting in nutrient-rich currents.{{how|date=March 2013}} Because of this, some large banks, such as Dogger Bank and the Grand Banks of Newfoundland, are among the richest fishing grounds in the world.

There are some banks that were reported in the 19th century by navigators, such as Wachusett Reef, whose existence is doubtful.

Types

Ocean banks may be of volcanic nature. Banks may be carbonate or terrigenous. In tropical areas some banks are submerged atolls. As they are not associated with any landmass, banks have no outside source of sediments.

Carbonate banks are typically platforms, rising from the ocean depths, whereas terrigenous banks are elevated sedimentary deposits.Morelock, J. (2005). [https://web.archive.org/web/20070106165300/http://geology.uprm.edu/Morelock/marg.htm Morphology]. Geological Oceanography Program, University of Puerto Rico at Mayagüez (UPRM). Retrieved on: October 11, 2008.

Seamounts, by contrast, are mountains rising from the deep sea and are steeper and higher in comparison to the surrounding seabed.Farallones Marine Sanctuary Association. [http://www.farallones.org/findings/documents/Geology.pdf Islands, Banks & Seamounts: Geologic Features Under the Sea] {{webarchive|url=https://web.archive.org/web/20061215125219/http://www.farallones.org/findings/documents/Geology.pdf |date=2006-12-15 }}. Examples of these are Pioneer and Guide Seamounts, west of the Farallon Islands. The Pioneer Seamount has a depth of 1,000 meters, In other cases, parts of a bank may reach above the water surface, thereby forming islands.World Wildlife Fund. [http://www.panda.org/about_wwf/what_we_do/marine/blue_planet/deep_sea/seamounts/index.cfm Deep sea ecology: seamounts]. Retrieved on: October 11, 2008.

Prominent banks

The largest banks in the world are:

  1. Grand Banks of Newfoundland (280,000 km2)Fisheries and Oceans Canada [http://www.dfo-mpo.gc.ca/overfishing-surpeche/media/bk_grandbanks_e.htm Backgrounder: The Grand Banks and the Flemish Cap]. Retrieved on: October 11, 2008. - terrigenous bank
  2. Agulhas Bank (116,000 km2){{Cite web

| last = Whittle | first = C. P.

| title = Characterization of Agulhas Bank upwelling variability from satellite-derived sea surface temperature and ocean colour products

| year = 2012 | publisher = American Geophysical Union Chapman Conference

| url = http://chapman.agu.org/agulhas/files/2012/11/Whittle_Poster_Chapman_2012_01.pdf | access-date = 29 March 2015}}

  1. Great Bahama Bank (95,798.12 km2, has islands, area without islands)
  2. Saya de Malha (35,000 km2, excluding the separate North bank, least depth 7 m)
  3. Seychelles Bank (31,000 km2, including islands of 266 km2)
  4. Georges Bank (28,800 km2) - terrigenous bank
  5. Lansdowne Bank (4,300 km2,[http://docplayer.fr/65661420-Le-parc-naturel-de-la-mer-de-corail.html Le parc naturel de la mer de Corail], p. 26 west of New Caledonia, least depth 3.7 m)
  6. Dogger Bank (17,600 km2, least depth 13 m)
  7. Little Bahama Bank (14,260.64 km2, has islands, area without islands)
  8. Great Chagos Bank (12,642 km2, including islands of 4.5 km2)
  9. Reed Bank, Spratly Islands (8,866 km2, least depth 9 m)
  10. Caicos Bank, Caicos Islands (7,680 km2, including islands of 589.5 km2)
  11. Macclesfield Bank (6,448 km2, least depth 9.2 m)
  12. North Bank or Ritchie Bank (5,800 km2, north of Saya de Malha, least depth <10 m)
  13. Cay Sal Bank (5,226.73 km2, including islands of 14.87 km2)
  14. Rosalind Bank (4,500 km2, least depth 7.3 m)
  15. Bassas de Pedro (2,474.33 km2, least depth 16.4 m), part of the Amindivi Subgroup of Lakshadweep, India

See also

Notes

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External links

  • [https://web.archive.org/web/20061215125219/http://www.farallones.org/findings/documents/Geology.pdf Definitions – Islands, Banks & Seamounts: Geologic Features Under the Sea]

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Category:Physical oceanography