Dom João de Castro Bank ( pt, Banco de D. João de Castro) is a large
submarine volcano located in the central north
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
, between the islands of
São Miguel and
Terceira
Terceira () is a volcanic island in the Azores archipelago, in the middle of the North Atlantic Ocean. It is one of the larger islands of the archipelago, with a population of 53,311 inhabitants in an area of approximately . It is the location ...
in the archipelago of the
Azores
)
, motto =( en, "Rather die free than subjected in peace")
, anthem= ( en, "Anthem of the Azores")
, image_map=Locator_map_of_Azores_in_EU.svg
, map_alt=Location of the Azores within the European Union
, map_caption=Location of the Azores wi ...
.
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The first historical reference correlated with the submarine volcanoes between São Miguel and Terceira occurred after two ships of the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 an explosive style of volcanic 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 ...
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.][
]
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 other 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 (someti ...
with polygonal surface fractures, while the older, less distinct crater is obscured by tephra
Tephra is fragmental material produced by a 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, they re ...
deposits.
Biome
D. João de Castro Bank showcases significant biodiversity
Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic (''genetic variability''), species (''species diversity''), and ecosystem (''ecosystem diversity'') l ...
, 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 fish of the family Balistidae. Often marked by lines and spots, they inhabit tropical and subtropical oceans throughout the world, with the greatest species richness in the Indo-Pacifi ...
(family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
''Balistidae''), needlefish (family ''Belonidae''), wahoo
Wahoo (''Acanthocybium solandri'') is a scombrid fish found worldwide in tropical and subtropical seas. It is best known to sports fishermen, as its speed and high-quality flesh makes it a prized and valued game fish. In Hawaii, the wahoo is kn ...
(''Acanthocybium solandri''), and giant oceanic manta ray
The giant oceanic manta ray, giant manta ray, or oceanic manta ray (''Mobula birostris'') is a species of ray in the family Mobulidae, and the largest type of ray in the world. It is circumglobal and is typically found in tropical and subtropica ...
(''Mobula birostris''). The dominant species of aquatic flora are ''Sargassum
''Sargassum'' is a genus of brown (class Phaeophyceae) macroalgae ( seaweed) in the order Fucales. Numerous species are distributed throughout the temperate and tropical oceans of the world, where they generally inhabit shallow water and coral ...
'' seaweeds.
The bank is an important fishing ground for demersal fish, such as the black seabream
The black seabream (''Spondyliosoma cantharus'') is a species of Sparidae fishes. They are recognisable by their oval compressed body and jaws containing 4-6 rows of slender teeth which are larger at the front. They are silvery in colour with bl ...
(''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 (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or w ...
tuna
A 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 bullet tuna (max len ...
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. ...
'' 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.[
]
See also
* List of volcanoes in Azores
References
;Notes
;Sources
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{{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