Diagrammatic cross-section of an oceanic basin, showing the relationship of the abyssal plain to a continental rise and an oceanic trenchDepiction of the abyssal zone in relation to other major oceanic zones
Aquatic layers
Pelagic
Photic
Epipelagic
Aphotic
Mesopelagic
Bathypelagic
Abyssopelagic
Hadopelagic
Demersal
Benthic
Stratification
Pycnocline
Isopycnal
Chemocline
Nutricline
Halocline
Thermocline
Thermohaline
See also
Marine habitats
Lake stratification
Ocean stratification
Aquatic ecosystems
Wild fisheries
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An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between 3,000 and 6,000 metres (9,800 and 19,700 ft). Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth's surface.[1][2] They are among the flattest, smoothest, and least explored regions on Earth.[3] Abyssal plains are key geologic elements of oceanic basins (the other elements being an elevated mid-ocean ridge and flanking abyssal hills).
The creation of the abyssal plain is the result of the spreading of the seafloor (plate tectonics) and the melting of the lower oceanic crust. Magma rises from above the asthenosphere (a layer of the upper mantle), and as this basaltic material reaches the surface at mid-ocean ridges, it forms new oceanic crust, which is constantly pulled sideways by spreading of the seafloor. Abyssal plains result from the blanketing of an originally uneven surface of oceanic crust by fine-grained sediments, mainly clay and silt. Much of this sediment is deposited by turbidity currents that have been channelled from the continental margins along submarine canyons into deeper water. The rest is composed chiefly of pelagic sediments. Metallic nodules are common in some areas of the plains, with varying concentrations of metals, including manganese, iron, nickel, cobalt, and copper. There are also amounts of carbon, nitrogen, phosphorus and silicon, due to material that comes down and decomposes.
Owing in part to their vast size, abyssal plains are believed to be major reservoirs of biodiversity. They also exert significant influence upon ocean carbon cycling, dissolution of calcium carbonate, and atmospheric CO2 concentrations over time scales of a hundred to a thousand years. The structure of abyssal ecosystems is strongly influenced by the rate of flux of food to the seafloor and the composition of the material that settles. Factors such as climate change, fishing practices, and ocean fertilization have a substantial effect on patterns of primary production in the euphotic zone.[1][4] Animals absorb dissolved oxygen from the oxygen-poor waters. Much dissolved oxygen in abyssal plains came from polar regions that had melted long ago. Due to scarcity of oxygen, abyssal plains are inhospitable for organisms that would flourish in the oxygen-enriched waters above. Deep sea coral reefs are mainly found in depths of 3,000 meters and deeper in the abyssal and hadal zones.
Abyssal plains were not recognized as distinct physiographic features of the sea floor until the late 1940s and, until recently, none had been studied on a systematic basis. They are poorly preserved in the sedimentary record, because they tend to be consumed by the subduction process. Due to darkness and a water pressure that can reach about 750 times atmospheric pressure (76 megapascal), abyssal plains are not well explored.
^ abCraig R. Smith; Fabio C. De Leo; Angelo F. Bernardino; Andrew K. Sweetman; Pedro Martinez Arbizu (2008). "Abyssal food limitation, ecosystem structure and climate change" (PDF). Trends in Ecology and Evolution. 23 (9): 518–528. doi:10.1016/j.tree.2008.05.002. PMID 18584909. Archived from the original (PDF) on 20 July 2011. Retrieved 18 June 2010.
^N.G. Vinogradova (1997). "Zoogeography of the Abyssal and Hadal Zones". The Biogeography of the Oceans. Advances in Marine Biology. Vol. 32. pp. 325–387. doi:10.1016/S0065-2881(08)60019-X. ISBN 9780120261321.
^P.P.E. Weaver; J. Thomson; P. M. Hunter (1987). Geology and Geochemistry of Abyssal Plains(PDF). Oxford: Blackwell Scientific Publications. p. x. ISBN 978-0-632-01744-7. Archived from the original (PDF) on 24 December 2010. Retrieved 18 June 2010.
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accumulated sediments that lies between the continental slope and the abyssalplain. It is a major part of the continental margin, covering around 10% of...
rise and a mid-ocean ridge, abyssalplains are among the flattest, smoothest and least explored regions on Earth. Abyssalplains are key geologic elements...
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The abyssal zone or abyssopelagic zone is a layer of the pelagic zone of the ocean. The word abyss comes from the Greek word ἄβυσσος (ábussos), meaning...
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demersal fish living on the bottom of the Atlantic Ocean, even on the abyssalplain. It is one of the deepest-dwelling fish known. This solitary fish grows...
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The Haunted from Revolver Abyssalplain, a flat area on the ocean floor Abyssal zone, a deep extent of the sea Into the Abyss (disambiguation) Bezdna (disambiguation)...
eroding the continental slope and finally depositing sediment onto the abyssalplain, where the particles settle out. About 3% of submarine canyons include...
depositional plains include: Abyssalplains, flat or very gently sloping areas of the deep ocean basin. Planitia /pləˈnɪʃiə/, the Latin word for plain, is used...
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An abyssal hill is a small hill that rises from the floor of an abyssalplain. They are the most abundant geomorphic structures on Earth, covering more...
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shelf. The continental margin, between the continental shelf and the abyssalplain, comprises a steep continental slope, surrounded by the flatter continental...
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the 19th century from the Madeira AbyssalPlain, and subsequent specimens have been found in other abyssalplains of both the Atlantic and Pacific Oceans...
foraminiferal ooze that had dried into dust and been blown about on the hot dry abyssalplain by sandstorms, mixed with quartz sand blown in from nearby continents...
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