# abyssal plain researcher henry swanson thinks the notion of 'abyssal plain' awesome and intense ![[oceanicbasin.svg.png]] diagrammatic cross-section of an oceanic basin showing the relationship of the abyssal plain to a continental rise and an oceanic trench ![[oceanicdivisions.svg.png]] depiction of the abyssal zone in relation to other major oceanic zones 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. they are among the flattest smoothest and least explored regions on earth. 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 ir 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 fertilisation have a substantial effect on patterns of primary production in the euphotic zone. 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 > tiefer tiefer irgendwo in der tiefe gibt es ein licht (deeper deeper somewhere in the depths there is a light) > ~ hello world by kate bush // republic of bob