Dom João de Castro Bank () is a large

submarine volcano Submarine volcanoes are underwater vents or fissures in the Earth's surface from which magma can erupt. Many submarine volcanoes are located near areas of tectonic plate formation, known as mid-ocean ridges. The volcanoes at mid-ocean ridges ...

located in the central north

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

, between the islands of São Miguel and

Terceira Terceira () is a volcanic island in the Azores archipelago, about a third of the way across the North Atlantic Ocean at a similar latitude to Portugal's capital Lisbon, with the island group forming an insular part of Portugal. It is one of the ...

in the archipelago of the

Azores The Azores ( , , ; , ), officially the Autonomous Region of the Azores (), is one of the two autonomous regions of Portugal (along with Madeira). It is an archipelago composed of nine volcanic islands in the Macaronesia region of the North Atl ...

History

The first historical reference correlated with the submarine volcanoes between São Miguel and Terceira occurred after two ships of the French corsair Henry Tourin sank in the spring of 1718. The last major eruption associated with this region occurred on 31 December 1720.Sérgio Paulo Ávila (1997), p.1 Beginning as a submarine eruption, it eventually built into a

Surtseyan eruption A Surtseyan eruption is a type of explosive eruption that takes place in shallow seas or lakes when rapidly rising and fragmenting hot magma interacts explosively with water and with water-steam- tephra slurries. The eruption style is named afte ...

that resulted in the formation of a circular island long and in altitude. Smoke and steam released by the eruption was visible from the islands of São Miguel and Terceira. The eruption also caused multiple small earthquakes felt on those islands. Designated the ''Ilha Nova'' (New Island), it remained above sea-level for only two years, reaching a height of and diameter of . Marine erosion and ocean swells reduced and degraded the cone's size considerably, so that by 21 July 1722 the ''Conselho da Marinha Português'' (Portuguese Marine Council) was advised the island had disappeared (Oliveira, 1943). After two centuries of disputed references to the existence of the island, on 28 July 1941 the hydrographic ship ''NH D. João de Castro'' identified its position and cataloged the morphology of the bank. In keeping with nautical tradition, the bank inherited the discovering ship's name. Intense seismic activity in the area in 1997 suggests a small eruption may have occurred in that year. The most recent seismic events from the region occurred from 4 June 2012, when incrementally increasing tremors affected the region. A maximum seismic event was recorded from the islands of São Miguel and Terceira, equivalent to levels III/IV on the

Mercalli Scale The Modified Mercalli intensity scale (MM, MMI, or MCS) measures the effects of an earthquake at a given location. This is in contrast with the seismic magnitude usually reported for an earthquake. Magnitude scales measure the inherent force or ...

Geography

The volcano remains seismically active between the islands of São Miguel and Terceira, rising to within of the sea surface. The volcano has a large

fumarole A fumarole (or fumerole) is a vent in the surface of the Earth or another rocky planet from which hot volcanic gases and vapors are emitted, without any accompanying liquids or solids. Fumaroles are characteristic of the late stages of volcani ...

field approximately in area. Volcanic gases released from the fumaroles are visible on the water's surface. Two parasitic craters, both about wide, are located on the northwest flank. The younger crater displays a floor consisting of a chilled

lava lake Lava lakes are large volumes of molten lava, usually basaltic, contained in a volcanic vent, crater, or broad depression. The term is used to describe both lava lakes that are wholly or partly molten and those that are solidified (sometim ...

with polygonal surface fractures, while the older, less distinct crater is obscured by

tephra Tephra is fragmental material produced by a Volcano, volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, ...

deposits.

Biome

D. João de Castro Bank showcases significant

biodiversity Biodiversity is the variability of life, life on Earth. It can be measured on various levels. There is for example genetic variability, species diversity, ecosystem diversity and Phylogenetics, phylogenetic diversity. Diversity is not distribut ...

, with approximately 220 identified species. Fish species observed near the bank include Bermuda chub ('' Kyphosus sectatrix''),

triggerfish Triggerfish are about 40 species of often brightly colored marine ray-finned fishes belonging to the family Balistidae. Often marked by lines and spots, they inhabit tropical and subtropical oceans throughout the world, with the greatest speci ...

(

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

''Balistidae''),

needlefish Needlefish (family Belonidae) or long toms are piscivorous fishes primarily associated with very shallow marine habitats or the surface of the open sea. Some genera include species found in marine, brackish, and freshwater environments (e.g., ...

(family ''Belonidae''),

wahoo The wahoo (''Acanthocybium solandri'') is a scombrid fish found worldwide in tropical and subtropical seas. In Hawaii, the wahoo is known as ono. The species is sometimes called hoo in the United States. It is best known to sports fishermen, a ...

(''Acanthocybium solandri''), and giant oceanic manta ray (''Mobula birostris''). The dominant species of aquatic flora are ''

Sargassum ''Sargassum'' is a genus of brown macroalgae ( seaweed) in the order Fucales of the Phaeophyceae class. Numerous species are distributed throughout the temperate and tropical oceans of the world, where they generally inhabit shallow water and ...

'' seaweeds. The bank is an important fishing ground for

demersal fish Demersal fish, also known as groundfish, live and feed on or near the bottom of seas or lakes (the demersal zone).Walrond Carl . "Coastal fish - Fish of the open sea floor"Te Ara - the Encyclopedia of New Zealand. Updated 2 March 2009 They oc ...

, such as the

black seabream The black seabream (''Spondyliosoma cantharus'') is a species of marine ray-finned fish belonging to the family Sparidae, which includes the seabreams and porgies. This fish has a wide distribution in the eastern Atlantic Ocean and the Mediterran ...

(''Spondyliosoma cantharus'') and

blackbelly rosefish ''Helicolenus dactylopterus'', blackbelly rosefish, bluemouth rockfish, and bluemouth seaperch, is a species of marine ray-finned fish belonging to the subfamily Sebastinae which is classified within the family Scorpaenidae. This Atlantic specie ...

(''Helicolenus dactylopterus''), as well as

pelagic The pelagic zone consists of the water column of the open ocean and can be further divided into regions by depth. The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the sur ...

tuna A tuna (: tunas or tuna) is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae ( mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bul ...

species (''

Thunnus ''Thunnus'' is a genus of ocean-dwelling, ray-finned bony fish from the mackerel family, Scombridae. More specifically, ''Thunnus'' is one of five genera which make up the tribe Thunnini – a tribe that is collectively known as the tunas. Al ...

'' and others). On 27 July 1996, in a scientific expedition organized by the ''Clube Naval de Ponta Delgada'', marine biology researchers from the

University of the Azores The University of the Azores (Portuguese: ''Universidade dos Açores''), or commonly abbreviated as ''UAc'', is the only public university in the Autonomous Region of the Azores. It was founded on January 9, 1976, two years after the Carnation Re ...

completed a study identifying species localized within the bank.

References

;Notes ;Sources * * * * {{DEFAULTSORT:Dom Joao de Castro Bank Volcanoes of Portugal Protected areas of Portugal Seamounts of the Atlantic Ocean Islands of the Azores Ephemeral islands Former islands from the last glacial maximum

History

Geography

Biome

See also

References