1.
Abyssal plain
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An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between 3,000 metres and 6,000 metres. Lying generally between the foot of a 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. In addition to elements, active oceanic basins also typically include an oceanic trench. Abyssal plains were not recognized as distinct physiographic features of the sea floor until the late 1940s and, until very recently and they are poorly preserved in the sedimentary record, because they tend to be consumed by the subduction process. The creation of the plain is the end result of spreading of the seafloor. Magma rises from above the asthenosphere and as this material reaches the surface at mid-ocean ridges it forms new oceanic crust. This 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 down into deeper water, the remainder of the sediment is composed chiefly of pelagic sediments. Metallic nodules are common in areas of the plains, with varying concentrations of metals, including manganese, iron, nickel, cobalt. These nodules may provide a significant resource for future mining ventures, owing in part to their vast size, abyssal plains are currently believed to be a major reservoir of biodiversity. The abyss also exerts significant influence upon ocean carbon cycling, dissolution of calcium carbonate, the structure and function of abyssal ecosystems are strongly influenced by the rate of flux of food to the seafloor and the composition of the material that settles. Factors such as change, fishing practices, and ocean fertilization are expected to have a substantial effect on patterns of primary production in the euphotic zone. This will undoubtedly impact the flux of material to the abyss in a similar manner and thus have a profound effect on the structure, function. The ocean can be conceptualized as being divided into zones, depending on depth. Photosynthesis in turn requires energy from sunlight to drive the chemical reactions that produce organic carbon, the stratum of the water column nearest the surface of the ocean is referred to as the photic zone. The photic zone can be subdivided into two different vertical regions, the uppermost portion of the photic zone, where there is adequate light to support photosynthesis by phytoplankton and plants, is referred to as the euphotic zone. The lower portion of the zone, where the light intensity is insufficient for photosynthesis, is called the dysphotic zone
2.
Abyssal (EP)
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Abyssal is an EP by the Japanese screamo band Envy. Abyssal likens itself with Insomniac Dozes more atmospheric sound, recorded and mixed at Bazooka Higashinakano, Spring 2007. Includes booklet with lyrics in both Japanese & English
3.
Pelagic zone
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Any water in a sea or lake that is neither close to the bottom nor near the shore can be said to be in the pelagic zone. The word pelagic is derived from Greek πέλαγος, meaning open sea, the pelagic zone can be thought of in terms of an imaginary cylinder or water column that goes from the surface of the sea almost to the bottom. Conditions differ deeper in the water such that as pressure increases with depth. Depending on the depth, the column, rather like the Earths atmosphere. The pelagic zone occupies 1,330 million km3 with a depth of 3.68 km. Pelagic life decreases with increasing depth and it is affected by light intensity, pressure, temperature, salinity, the supply of dissolved oxygen and nutrients, and the submarine topography, which is called bathymetry. In deep water, the zone is sometimes called the open-ocean zone. In other contexts, coastal water not near the bottom is still said to be in the pelagic zone, the pelagic zone can be contrasted with the benthic and demersal zones at the bottom of the sea. The benthic zone is the region at the very bottom of the sea. It includes the sediment surface and some subsurface layers, Marine organisms living in this zone, such as clams and crabs, are called benthos. The demersal zone is just above the benthic zone and it can be significantly affected by the seabed and the life that lives there. Demersal fish are known as bottom feeders and groundfish. Depending on how deep the sea is, the zone can extend over up to five horizontal layers in the ocean. From the top down, these are, From the surface down to around 200 m This is the zone at the surface of the sea where enough light is available for photosynthesis. Nearly all primary production in the ocean occurs here, consequently, plants and animals are largely concentrated in this zone. Examples of organisms living in this zone are plankton, floating seaweed, jellyfish, tuna, many sharks, from 200 m down to around 1,000 m The name for this zone stems from Greek μέσον, meaning middle. Although some light penetrates this second layer it is insufficient for photosynthesis, at about 500 m the water also becomes depleted of oxygen. Organisms survive this environment by having more efficient gills or by minimizing movement, examples of animals that live here are swordfish, squid, Anarhichadidae or wolffish and some species of cuttlefish
4.
Photic zone
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The photic zone, euphotic zone, or sunlight or zone is the depth of the water in a lake or ocean that is exposed to such intensity of sunlight which designates compensation point, i. e. It extends from the surface down to a depth where light intensity falls to one percent of that at the surface, accordingly, its thickness depends on the extent of light attenuation in the water column. Typical euphotic depths vary from only a few centimetres in highly turbid eutrophic lakes and it also varies with seasonal changes in turbidity. About 90% of all marine life lives in the photic zone, a small amount of primary production is generated deep in the abyssal zone around the hydrothermal vents which exist along some mid-oceanic ridges. The zone which extends from the base of the zone to about 200 metres is sometimes called the disphotic zone. While there is light, it is insufficient for photosynthesis. The euphotic zone together with the disphotic zone coincides with the epipelagic zone, the bottommost zone, below the euphotic zone, is called the aphotic zone. Most deep ocean waters belong to this zone, the transparency of the water, which determines the depth of the photic zone, is measured simply with a Secchi disk. It may also be measured with a photometer lowered into the water, electromagnetic absorption by water Epipelagic fish
5.
Mesopelagic zone
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The mesopelagic is that part of the pelagic zone that extends from a depth of 200 to 1000 metres below the ocean surface. It lies between the photic epipelagic above and the aphotic bathypelagic below, where there is no light at all, although some light penetrates the mesopelagic zone, it is insufficient for photosynthesis. The general types of forms found are daytime visiting herbivores, detritivores feeding on dead organisms and fecal pellets. Examples of animals in the zone are, bristlemouth, swordfish, squid, wolf eels, cuttlefish. The bristlemouth is the Earths most abundant vertebrate, numbering in the hundreds of trillions to quadrillions, the small amount of sunlight is sufficient for animals, such as the chain catshark, to be fluorescent. As of 2015 its small commercial fishery targeted meal, oil, the quantity of mesopelagic life is large enough to play a significant role in global carbon cycling. As the fish participate in the chain, they acquire carbon rendered from carbon dioxide absorbed by surface waters. Upon death, they transport that carbon into the abyss, as of 2015 the revised estimates of mesopelagic life had yet to be incorporated into climate models
6.
Bathyal zone
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The bathyal zone or bathypelagic – from Greek βαθύς, deep – is the part of the pelagic zone that extends from a depth of 1000 to 4000 meters below the ocean surface. It lies between the mesopelagic above, and the abyssopelagic below, the average temperature hovers at about 4 °C. Although larger by volume than the euphotic zone, the zone is less densely populated. Sunlight does not reach this zone, meaning primary production, if any, is almost nonexistent, there are no known plants because of the lack of sunlight necessary for photosynthesis. It is known as the zone because of this feature. Because of the lack of light, some species do not have eyes, however those possessing eyes in this include the viperfish. Many forms of live in the bathyal zone, such as squid, large whales. In the bathyal, some of the worlds largest whales feed, sponges, brachiopods, sea stars, and echinoids are also common in the bathyal zone. Animals in the zone are not threatened by predators that can see them. This zone is difficult for fish to live in, since it is hard to find nutrients. They have become very efficient, and many have slow metabolic rates to conserve energy. The fish are characterized by weak muscles, soft skin and slimy bodies, the adaptations of some of the fish that live there include small eyes and transparent skin. Except where the ocean is deep, the bathyal zone extends to the benthic zone on the ocean bed of that part of the continental slope that lies between 1000 and 4000 meters deep. The bathyal zone contains sharks, squid, octopuses, and many different species of fish, bathyal zones on the Mediterranean continental slope, An attempt. Research on marine benthos, 9th Iberian Symposium on Studies of Marine Benthos
7.
Hadal zone
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The hadal zone, also known as the hadopelagic zone and composed of trench zones, is the delineation for the deepest trenches in the ocean. The hadal zone is found from a depth to the bottom of the ocean of around 6,000 to 11,000 metres and exists in long, in total there are 33 trenches and 13 troughs around the world—46 individual hadal habitats in total. All the trenches together occupy an area less than one-quarter of one percent of the entire seafloor, the hadal zone has low population and low diversity of marine life. It is believed that most life at this depth is sustained by marine snow or the chemical reactions around thermal vents, the low nutrient level, extreme pressure and lack of sunlight create hostile living conditions in which few species are able to exist. As no sunlight reaches this layer of the ocean, deep sea creatures have reduced eyesight, the most common organisms include jellyfish, viperfish, tube worms and sea cucumbers. The hadal zone can reach far below 6,000 meters deep, at such depths the pressure in the hadal zone exceeds 1,100 standard atmospheres. In 1960, Jacques Piccard and Don Walsh reached the bottom of the Mariana Trench, the deepest known trench on Earth, james Cameron also reached the bottom in 2012 using the Deepsea Challenger. Abyssal plain Deep sea Alan Jamieson, The hadal zone - life in the deepest oceans, forscher filmen lebende Fische in Rekordtiefe from Spiegel 10/09/2008 about an expedition filming fish at a depth of more than 7,000 m
8.
Demersal zone
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The demersal zone is the part of the sea or ocean consisting of the part of the water column near to the seabed and the benthos. The demersal zone is just above the zone and forms a layer of the larger profundal zone. The distinction between species of fish and pelagic species is not always clear cut. Two types of fish inhabit the zone, those that are heavier than water and rest on the seabed. In many species of fish, neutral buoyancy is maintained by a swim bladder which can be expanded or contracted as the circumstances require. A disadvantage of this method is that adjustments need to be made constantly as the pressure varies when the fish swims higher and lower in the water column. An alternative buoyancy aid is the use of lipids, these are less dense water and squalene. In the velvet belly lanternshark, a species, 17% of the bodyweight is liver. Benthic rays and skates have smaller livers with lower concentrations of lipids, they are denser than water. Some fish have no buoyancy aids but use their pectoral fins which are so angled as to lift as they swim. The disadvantage of this is that, if they stop swimming, the fish sink, demersal fish have various feeding strategies, many feed on zooplankton or organisms or algae on the seabed, some of these feed on epifauna, while others specialise on infauna. Others are scavengers, eating the remains of plants or animals while still others are predators. Zooplankton are animals that drift with the current, but many have limited means of locomotion and have some control over the depths at which they drift. They use gas-filled sacs or accumulations of substances with low densities to provide buoyancy, where the adult, benthic organism is limited to life in a certain range of depths, their larvae need to optimise their chances of settling on a suitable substrate. Cuttlefish are able to adjust their buoyancy using their cuttlebones, lightweight rigid structures with cavities filled with gas and this enables them to swim at varying depths. Another invertebrate that feeds on the seabed and has swimming abilities is the nautilus, which stores gas in its chambers and adjusts its buoyancy by use of osmosis, pumping water in and out
