1.
Marine habitats
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The marine environment supplies many kinds of habitats that support marine life. Marine life depends in some way on the saltwater that is in the sea, a habitat is an ecological or environmental area inhabited by one or more living species. Marine habitats can be divided into coastal and open ocean habitats, coastal habitats are found in the area that extends from as far as the tide comes in on the shoreline out to the edge of the continental shelf. Most marine life is found in habitats, even though the shelf area occupies only seven percent of the total ocean area. Open ocean habitats are found in the ocean beyond the edge of the continental shelf. Alternatively, marine habitats can be divided into pelagic and demersal zones, pelagic habitats are found near the surface or in the open water column, away from the bottom of the ocean. Demersal habitats are near or on the bottom of the ocean, an organism living in a pelagic habitat is said to be a pelagic organism, as in pelagic fish. Similarly, a living in a demersal habitat is said to be a demersal organism. Pelagic habitats are shifting and ephemeral, depending on what ocean currents are doing. Marine habitats can be modified by their inhabitants, some marine organisms, like corals, kelp, mangroves and seagrasses, are ecosystem engineers which reshape the marine environment to the point where they create further habitat for other organisms. In contrast to terrestrial habitats, marine habitats are shifting and ephemeral, swimming organisms find areas by the edge of a continental shelf a good habitat, but only while upwellings bring nutrient rich water to the surface. Shellfish find habitat on sandy beaches, but storms, tides, the presence of seawater is common to all marine habitats. Beyond that many other things determine whether a marine area makes a good habitat, the ocean occupies 71 percent of the world surface, averaging nearly four kilometres in depth. There are five major oceans, of which the Pacific Ocean is nearly as large as the rest put together, coastlines fringe the land for nearly 380,000 kilometres. Marine habitats can be divided into pelagic and demersal habitats. Pelagic habitats are the habitats of the water column, away from the bottom of the ocean. Demersal habitats are the habitats that are near or on the bottom of the ocean, an organism living in a pelagic habitat is said to be a pelagic organism, as in pelagic fish. Similarly, a living in a demersal habitat is said to be a demersal organism
2.
United States Navy
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The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U. S. Navy is the largest, most capable navy in the world, the U. S. Navy has the worlds largest aircraft carrier fleet, with ten in service, two in the reserve fleet, and three new carriers under construction. The service has 323,792 personnel on duty and 108,515 in the Navy Reserve. It has 274 deployable combat vessels and more than 3,700 operational aircraft as of October 2016, the U. S. Navy traces its origins to the Continental Navy, which was established during the American Revolutionary War and was effectively disbanded as a separate entity shortly thereafter. It played a role in the American Civil War by blockading the Confederacy. It played the role in the World War II defeat of Imperial Japan. The 21st century U. S. Navy maintains a global presence, deploying in strength in such areas as the Western Pacific, the Mediterranean. The Navy is administratively managed by the Department of the Navy, the Department of the Navy is itself a division of the Department of Defense, which is headed by the Secretary of Defense. The Chief of Naval Operations is an admiral and the senior naval officer of the Department of the Navy. The CNO may not be the highest ranking officer in the armed forces if the Chairman or the Vice Chairman of the Joint Chiefs of Staff. The mission of the Navy is to maintain, train and equip combat-ready Naval forces capable of winning wars, deterring aggression, the United States Navy is a seaborne branch of the military of the United States. The Navys three primary areas of responsibility, The preparation of naval forces necessary for the prosecution of war. The development of aircraft, weapons, tactics, technique, organization, U. S. Navy training manuals state that the mission of the U. S. Armed Forces is to prepare and conduct prompt and sustained combat operations in support of the national interest, as part of that establishment, the U. S. Navys functions comprise sea control, power projection and nuclear deterrence, in addition to sealift duties. It follows then as certain as that night succeeds the day, that without a decisive naval force we can do nothing definitive, the Navy was rooted in the colonial seafaring tradition, which produced a large community of sailors, captains, and shipbuilders. In the early stages of the American Revolutionary War, Massachusetts had its own Massachusetts Naval Militia, the establishment of a national navy was an issue of debate among the members of the Second Continental Congress. Supporters argued that a navy would protect shipping, defend the coast, detractors countered that challenging the British Royal Navy, then the worlds preeminent naval power, was a foolish undertaking. Commander in Chief George Washington resolved the debate when he commissioned the ocean-going schooner USS Hannah to interdict British merchant ships, and reported the captures to the Congress
3.
Intertidal zone
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The intertidal zone, also known as the foreshore and seashore and sometimes referred to as the littoral zone, is the area that is above water at low tide and under water at high tide. This area can include different types of habitats, with many types of animals, such as starfish, sea urchins. The well-known area also includes rocky cliffs, sandy beaches. The area can be a strip, as in Pacific islands that have only a narrow tidal range. Organisms in the zone are adapted to an environment of harsh extremes. The intertidal zone is home to many several species from different taxa including Porifera, Annelids, Coelenterates, Mollusks, crustaceans, Arthropods. Water is available regularly with the tides but varies from fresh with rain to highly saline, wave splash can dislodge residents from the littoral zone. With the intertidal zones high exposure to the sun, the range can be anything from very hot with full sun to near freezing in colder climates. Some microclimates in the zone are ameliorated by local features. Adaptation in the littoral zone allows the use of nutrients supplied in high volume on a basis from the sea. Edges of habitats, in this land and sea, are themselves often significant ecologies. Along most shores, the zone can be clearly separated into the following subzones, high tide zone, middle tide zone. The intertidal zone is one of a number of biomes or habitats, including estuaries, neritic, surface. Marine biologists divide the region into three zones, based on the overall average exposure of the zone. The low intertidal zone, which borders on the shallow subtidal zone, is exposed to air at the lowest of low tides and is primarily marine in character. The mid intertidal zone is exposed and submerged by average tides. The high intertidal zone is covered by the highest of the high tides. The high intertidal zone borders on the splash zone, on shores exposed to heavy wave action, the intertidal zone will be influenced by waves, as the spray from breaking waves will extend the intertidal zone
4.
Estuary
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An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a zone between river environments and maritime environments. They are subject both to marine influences—such as tides, waves, and the influx of saline water—and to riverine influences—such as flows of fresh water and sediment. The inflows of sea water and fresh water provide high levels of nutrients both in the water column and in sediment, making estuaries among the most productive natural habitats in the world. Most existing estuaries formed during the Holocene epoch with the flooding of river-eroded or glacially scoured valleys when the sea began to rise about 10. Estuaries are typically classified according to their geomorphological features or to water-circulation patterns, the banks of many estuaries are amongst the most heavily populated areas of the world, with about 60% of the worlds population living along estuaries and the coast. The word estuary is derived from the Latin word aestuarium meaning tidal inlet of the sea, there have been many definitions proposed to describe an estuary. However, this definition excludes a number of water bodies such as coastal lagoons. This broad definition also includes fjords, lagoons, river mouths, an estuary is a dynamic ecosystem having a connection to the open sea through which the sea water enters with the rhythm of the tides. The sea water entering the estuary is diluted by the water flowing from rivers. The pattern of dilution varies between different estuaries and depends on the volume of water, the tidal range. Drowned river valleys are known as coastal plain estuaries. In places where the sea level is rising relative to the land, sea water progressively penetrates into river valleys and this is the most common type of estuary in temperate climates. Well-studied estuaries include the Severn Estuary in the United Kingdom and the Ems Dollard along the Dutch-German border, the width-to-depth ratio of these estuaries is typically large, appearing wedge-shaped in the inner part and broadening and deepening seaward. Water depths rarely exceed 30 m, examples of this type of estuary in the U. S. are the Hudson River, Chesapeake Bay, and Delaware Bay along the Mid-Atlantic coast, and Galveston Bay and Tampa Bay along the Gulf Coast. They are relatively common in tropical and subtropical locations and these estuaries are semi-isolated from ocean waters by barrier beaches. Formation of barrier beaches partially encloses the estuary, with only narrow inlets allowing contact with the ocean waters, bar-built estuaries typically develop on gently sloping plains located along tectonically stable edges of continents and marginal sea coasts. They are extensive along the Atlantic and Gulf coasts of the U. S. in areas with active coastal deposition of sediments, barrier beaches form in shallow water and are generally parallel to the shoreline, resulting in long, narrow estuaries
5.
Kelp forest
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Kelp forests are underwater areas with a high density of kelp. They are recognized as one of the most productive and dynamic ecosystems on Earth, smaller areas of anchored kelp are called kelp beds. Kelp forests occur worldwide throughout temperate and polar coastal oceans, in 2007, kelp forests were also discovered in tropical waters near Ecuador. Physically formed by brown macroalgae, kelp forests provide a unique, over the last century, they have been the focus of extensive research, particularly in trophic ecology, and continue to provoke important ideas that are relevant beyond this unique ecosystem. For example, kelp forests can influence coastal oceanographic patterns and provide ecosystem services. However, the influence of humans has often contributed to kelp forest degradation, of particular concern are the effects of overfishing nearshore ecosystems, which can release herbivores from their normal population regulation and result in the overgrazing of kelp and other algae. This can rapidly result in transitions to barren landscapes where relatively few species persist, the term kelp refers to marine algae belonging to the order Laminariales. Though not considered a taxonomically diverse order, kelps are highly diverse structurally and functionally, the most widely recognized species are the giant kelps, although numerous other genera such as Laminaria, Ecklonia, Lessonia, Alaria, and Eisenia are described. Many marine mammals and birds are found, including seals, sea lions, whales, sea otters, gulls, terns, snowy egrets, great blue herons. Frequently considered an ecosystem engineer, kelp provides a physical substrate, in algae, the body of an individual organism is known as a thallus rather than as a plant. The stipe is analogous to a plant stalk, extending vertically from the holdfast, the fronds are leaf- or blade-like attachments extending from the stipe, sometimes along its full length, and are the sites of nutrient uptake and photosynthetic activity. In addition, many species have pneumatocysts, or gas-filled bladders. These structures provide the necessary buoyancy for kelp to maintain a position in the water column. The environmental factors necessary for kelp to survive include hard substrate, high nutrients, water flow and turbulence facilitate nutrient assimilation across kelp fronds throughout the water column. Water clarity affects the depth to which sufficient light can be transmitted, in ideal conditions, giant kelp can grow as much as 30-60 cm vertically per day. Some species, such as Nereocystis, are annuals, while others such as Eisenia are perennials, in perennial kelp forests, maximum growth rates occur during upwelling months and die-backs correspond to reduced nutrient availability, shorter photoperiods, and increased storm frequency. Kelps are primarily associated with temperate and arctic waters worldwide, the region with the greatest diversity of kelps is the northeastern Pacific, from north of San Francisco, California, to the Aleutian Islands, Alaska. Although kelp forests are unknown in tropical waters, a few species of Laminaria have been known to occur exclusively in tropical deep waters
6.
Coral reef
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Coral reefs are diverse underwater ecosystems held together by calcium carbonate structures secreted by corals. Coral reefs are built by colonies of tiny animals found in waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups, the polyps belong to a group of animals known as Cnidaria, which also includes sea anemones and jellyfish. Unlike sea anemones, corals secrete hard carbonate exoskeletons which support, most reefs grow best in warm, shallow, clear, sunny and agitated waters. Often called rainforests of the sea, shallow coral reefs form some of the most diverse ecosystems on Earth, paradoxically, coral reefs flourish even though they are surrounded by ocean waters that provide few nutrients. They are most commonly found at depths in tropical waters. Coral reefs deliver ecosystem services to tourism, fisheries and shoreline protection, the annual global economic value of coral reefs is estimated between US$29. 8-375 billion. However, coral reefs are fragile ecosystems, partly because they are sensitive to water temperature. Most of the coral reefs we can see today were formed after the last glacial period when melting ice caused the sea level to rise and this means that most modern coral reefs are less than 10,000 years old. As communities established themselves on the shelves, the reefs grew upwards, Reefs that rose too slowly could become drowned reefs. They are covered by so much water there was insufficient light. Coral reefs are found in the sea away from continental shelves, around oceanic islands. The vast majority of islands are volcanic in origin. The few exceptions have tectonic origins where plate movements have lifted the deep ocean floor on the surface. In 1842 in his first monograph, The Structure and Distribution of Coral Reefs, Charles Darwin set out his theory of the formation of atoll reefs and he theorized uplift and subsidence of the Earths crust under the oceans formed the atolls. Darwin’s theory sets out a sequence of three stages in atoll formation and it starts with a fringing reef forming around an extinct volcanic island as the island and ocean floor subsides. As the subsidence continues, the reef becomes a barrier reef. Darwin predicted that underneath each lagoon would be a bed rock base, where the level of the underlying earth allows, the corals grow around the coast to form what he called fringing reefs, and can eventually grow out from the shore to become a barrier reef
7.
Ocean bank
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An ocean bank, sometimes referred to as a fishing bank or simply bank, is a part of the sea which is shallow compared to its surrounding area, such as a shoal or the top of an underwater hill. Somewhat like continental slopes, ocean banks slopes can upwell as tidal and other flows intercept them, because of this, some large banks, such as Dogger Bank and the Grand Banks of Newfoundland, are among the richest fishing grounds in the world. There are some banks that were reported in the 19th century by navigators, such as Wachusett Reef, ocean banks may be of volcanic nature. Banks may be carbonate or terrigenous, in tropical areas some banks are submerged atolls. As they are not associated with any landmass, banks have no source of sediments. Carbonate banks are typically platforms, rising from the ocean depths, Seamounts, by contrast, are mountains, of volcanic origin, rising from the deep sea, and are steeper, and higher in comparison to the surrounding seabed. Examples of these are Pioneer and Guide Seamounts, west of the Farallon Islands, the Pioneer Seamount has a depth of 1,000 meters, In other cases, parts of a bank may reach above the water surface, thereby forming islands
8.
Continental shelf
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The continental shelf is an underwater landmass which extends from a continent, resulting in an area of relatively shallow water known as a shelf sea. Much of the shelves were exposed during glacial periods and interglacial periods, the shelf surrounding an island is known as an insular shelf. The continental margin, between the shelf and the abyssal plain, comprises a steep continental slope followed by the flatter continental rise. Sediment from the continent above cascades down the slope and accumulates as a pile of sediment at the base of the slope, extending as far as 500 km from the slope, it consists of thick sediments deposited by turbidity currents from the shelf and slope. The continental rises gradient is intermediate between the slope and the shelf, on the order of 0. 5–1°, the largest shelf – the Siberian Shelf in the Arctic Ocean – stretches to 1,500 kilometers in width. The South China Sea lies over another extensive area of shelf, the Sunda Shelf, which joins Borneo, Sumatra. Other familiar bodies of water that overlie continental shelves are the North Sea, the average width of continental shelves is about 80 km. The depth of the shelf also varies, but is limited to water shallower than 150 m. The slope of the shelf is quite low, on the order of 0. 5°, vertical relief is also minimal. Though the continental shelf is treated as a province of the ocean, it is not part of the deep ocean basin proper. Passive continental margins such as most of the Atlantic coasts have wide and shallow shelves, active continental margins have narrow, relatively steep shelves, due to frequent earthquakes that move sediment to the deep sea. The shelf usually ends at a point of increasing slope, the sea floor below the break is the continental slope. Below the slope is the rise, which finally merges into the deep ocean floor. The continental shelf and the slope are part of the continental margin, the shelf area is commonly subdivided into the inner continental shelf, mid continental shelf, and outer continental shelf, each with their specific geomorphology and marine biology. The character of the shelf changes dramatically at the shelf break, with a few exceptions, the shelf break is located at a remarkably uniform depth of roughly 140 m, this is likely a hallmark of past ice ages, when sea level was lower than it is now. The continental slope is steeper than the shelf, the average angle is 3°. The slope is cut with submarine canyons. The physical mechanisms involved in forming these canyons were not well understood until the 1960s, the continental shelves are covered by terrigenous sediments, that is, those derived from erosion of the continents
9.
Neritic zone
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The neritic zone is the relatively shallow part of the ocean above the drop-off of the continental shelf, approximately 200 meters in depth. It extends from the low tide mark to the edge of the continental shelf, above the neritic zone lie the intertidal and supralittoral zones, below it the continental slope begins, descending from the continental shelf to the abyssal plain and the pelagic zone. Within the neritic, marine biologists also identify the following, The infralittoral zone is the algal dominated zone to maybe five metres below the low water mark, the circalittoral zone is the region beyond the infralittoral, which is dominated by sessile animals such as oysters. The subtidal zone is the region of the zone which is below the intertidal zone. In particular, the zone in the neritic is much more stable than in the intertidal zone. Corals are also found in the neritic zone, where they are more common than in the intertidal zone as they have less change to deal with. As in marine biology, this typically extends to the edge of the continental shelf
10.
Strait
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A strait is a naturally formed, narrow, typically navigable waterway that connects two larger bodies of water. Most commonly it is a channel of water that lies between two land masses, some straits are not navigable, for example because they are too shallow, or because of an unnavigable reef or archipelago. The terms channel, pass or passage, can be synonymous and used interchangeably with strait, in Scotland firth or kyle are also sometimes used as synonyms for strait. Straits can be important shipping routes, and wars have been fought for control of them, numerous artificial channels, called canals, have been constructed to connect two bodies of water over land, such as the Suez Canal. Although rivers and canals often provide passage between two large lakes or a lake and a sea, and these seem to suit the formal definition of strait, the term strait is typically reserved for much larger, wider features of the marine environment. There are exceptions, with straits being called canals, Pearse Canal, Straits are the converse of isthmuses. That is, while a strait lies between two masses and connects two larger bodies of water, an isthmus lies between two bodies of water and connects two larger land masses. Some straits have the potential to generate significant tidal power using tidal stream turbines, tides are more predictable than wave power or wind power. The Pentland Firth may be capable of generating 10 GW, cook Strait in New Zealand may be capable of generating 5. There may be no suspension of innocent passage through such straits, list of straits Media related to Straits at Wikimedia Commons
11.
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
12.
Oceanic zone
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The oceanic zone begins in the area off shore where the water measures 200 meters deep or deeper and extends to the ocean floor. It is the region of open sea beyond the edge of the continental shelf, the oceanic zone has a wide array of undersea terrain, including crevices that are often deeper than Mount Everest is tall, as well as deep-sea volcanoes and ocean basins. While it is difficult for life to sustain itself in this type of environment. The oceanic zone is subdivided into the epipelagic, mesopelagic, the epipelagic zone, also called the sunlit zone, receives enough sunlight to support photosynthesis. The temperatures in this zone range anywhere from 40 to −3 °C, the mesopelagic zone, where only small amounts of light penetrate, lies below the epipelagic zone. This zone is referred to as the Twilight Zone due to its scarce amount of light. Temperatures in the zone range from 5 to 4 °C. The pressure is higher here, it can be up to 1,470 pounds per square inch, 90% of the ocean lies in the bathypelagic zone into which no light penetrates. This is also called the zone and the deep ocean. Due to the lack of sunlight, photosynthesis cannot occur. Water pressure is intense and the temperatures are near freezing Oceanographers have divided the ocean into zones based on how far light reaches. All of the zones can be found in the oceanic zone. The epipelagic zone is the one closest to the surface and is the best lit and it extends to 200 meters and contains both phytoplankton and zooplankton that can support larger organisms like marine mammals and some types of fish. Past 200 meters, not enough light penetrates the water to support life, there are creatures however, which thrive around hydrothermal vents, or geysers located on the ocean floor that expel super heated water that is rich in minerals. These organisms feed off of chemosynthetic bacteria, which use the super heated water, the existence of these bacteria allow creatures like squids, hatchet fish, octopuses, tube worms, giant clams, spider crabs and other organisms to survive. Due to the darkness in the zones past the epipelagic zone, many organisms that survive in the deep oceans do not have eyes. Often the light is green in colour, because many marine organisms are sensitive to blue light. Two chemicals, luciferin and luciferase that react with one another to create a soft glow, the process by which bioluminescence is created is very similar to what happens when a glow stick is broken
13.
Seamount
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A seamount is a mountain rising from the ocean seafloor that does not reach to the waters surface, and thus is not an island. Seamounts are typically formed from volcanoes that rise abruptly and are usually found rising from the seafloor to 1. They are defined by oceanographers as independent features that rise to at least 1,000 m above the seafloor, the peaks are often found hundreds to thousands of meters below the surface, and are therefore considered to be within the deep sea. During their evolution over time, the largest seamounts may reach the sea surface where wave action erodes the summit to form a flat surface. Seamounts and guyots are most abundant in the North Pacific Ocean, in recent years, several active seamounts have been observed, for example Loihi in the Hawaiian Islands. Because of their abundance, seamounts are one of the most common marine ecosystems in the world, interactions between seamounts and underwater currents, as well as their elevated position in the water, attract plankton, corals, fish, and marine mammals alike. Their aggregational effect has been noted by the fishing industry. There are ongoing concerns on the impact of fishing on seamount ecosystems. 95% of ecological damage is done by bottom trawling, which scrapes whole ecosystems off seamounts, because of their large numbers, many seamounts remain to be properly studied, and even mapped. Bathymetry and satellite altimetry are two technologies working to close the gap, there have been instances where naval vessels have collided with uncharted seamounts, for example, Muirfield Seamount is named after the ship that struck it in 1973. Seamounts can be found in every ocean basin in the world, a seamount is technically defined as an isolated rise in elevation of 1,000 m or more from the surrounding seafloor, and with a limited summit area, of conical form. If small knolls, ridges and hills less than 1,000 m in height are included there are over 100,000 seamounts in the world ocean. Most seamounts are volcanic in origin, and thus tend to be found on oceanic crust near mid-ocean ridges, mantle plumes, and island arcs. Overall, seamount and guyot coverage is greatest as a proportion of area in the North Pacific Ocean. The Arctic Ocean has only 16 seamounts and no guyots, the 9,951 seamounts mapped cover an area of 8,088,550 km2. The largest seamount has an area of 15,500 km2, guyots cover a total area of 707,600 km2 and have an average area of 2,500 km2, more than twice the average size of seamounts. Nearly 50% of guyot area and 42% of the number of guyots occur in the North Pacific Ocean, the largest three guyots are all in the North Pacific, the Kuko Guyot, Suiko Guyot and the Pallada Guyot. Seamount chain redirects here, for a broader coverage related to this topic, Seamounts are often found in groupings or submerged archipelagos, a classic example being the Emperor Seamounts, an extension of the Hawaiian Islands
14.
Hydrothermal vent
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A hydrothermal vent is a fissure in a planets surface from which geothermally heated water issues. Hydrothermal vents are found near volcanically active places, areas where tectonic plates are moving apart, ocean basins. Hydrothermal vents exist because the earth is both active and has large amounts of water on its surface and within its crust. Common land types include hot springs, fumaroles and geysers, under the sea, hydrothermal vents may form features called black smokers. Chemosynthetic bacteria and archaea form the base of the chain, supporting diverse organisms, including giant tube worms, clams, limpets. Active hydrothermal vents are believed to exist on Jupiters moon Europa, and Saturns moon Enceladus, Hydrothermal vents in the deep ocean typically form along the mid-ocean ridges, such as the East Pacific Rise and the Mid-Atlantic Ridge. These are locations where two plates are diverging and new crust is being formed. The proportion of each varies from location to location, in contrast to the approximately 2 °C ambient water temperature at these depths, water emerges from these vents at temperatures ranging from 60 to as high as 464 °C. Due to the hydrostatic pressure at these depths, water may exist in either its liquid form or as a supercritical fluid at such temperatures. The critical point of water is 375 °C at a pressure of 218 atmospheres, however, introducing salinity into the fluid raises the critical point to higher temperatures and pressures. The critical point of seawater is 407 °C and 298.5 bars, accordingly, if a hydrothermal fluid with a salinity of 3.2 wt. % NaCl vents above 407 °C and 298.5 bars, furthermore, the salinity of vent fluids have been shown to vary widely due to phase separation in the crust. The critical point for lower salinity fluids is at lower temperature and pressure conditions than that for seawater, for example, a vent fluid with a 2.24 wt. % NaCl salinity has the point at 400 °C and 280.5 bars. Thus, water emerging from the hottest parts of some hydrothermal vents can be a supercritical fluid, examples of supercritical venting are found at several sites. Sister Peak vents low salinity phase-separated, vapor-type fluids, sustained venting was not found to be supercritical but a brief injection of 464 °C was well above supercritical conditions. A nearby site, Turtle Pits, was found to vent low salinity fluid at 407 °C, which is above the critical point of the fluid at that salinity. A vent site in the Cayman Trough named Beebe, which is the worlds deepest known hydrothermal site at ~5000 m below sea level, has shown sustained supercritical venting at 401 °C and 2.3 wt% NaCl
15.
Cold seep
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A cold seep is an area of the ocean floor where hydrogen sulfide, methane and other hydrocarbon-rich fluid seepage occurs, often in the form of a brine pool. Cold does not mean that the temperature of the seepage is lower than that of the sea water. On the contrary, its temperature is slightly higher. Cold seeps constitute a biome supporting several endemic species, cold seeps develop unique topography over time, where reactions between methane and seawater create carbonate rock formations and reefs. These reactions may also be dependent on bacterial activity, ikaite, a hydrous calcium carbonate, can be associated with oxidizing methane at cold seeps. Types of cold seeps can be distinguished according to the depth, as cold seeps. Oil and methane seep out of fissures, get diffused by sediment. Methane is the component of what we commonly refer to as natural gas. But in addition to being an important energy source for humans, cold seep biota below 200 m typically exhibit much greater systematic specialization and reliance on chemoautotrophy than those from shelf depths. Deep-sea seeps sediments are highly heterogeneous and they sustain different geochemical and microbial processes that are reflected in a complex mosaic of habitats inhabited by a mixture of specialist and background fauna. Biological research in cold seeps and hydrothermal vents has been focused on the microbiology. Much less research has been done on the smaller benthic fraction at the size of the meiofauna, community compositions orderly shift from one set of species to another is called ecological succession, The first type of organism to take advantage of this deep-sea energy source is bacteria. Aggregating into bacterial mats at cold seeps, these bacteria metabolize methane and this process of obtaining energy from chemicals is known as chemosynthesis. During this initial stage, when methane is relatively abundant, dense mussel beds also form near the cold seep, mostly composed of species in the genus Bathymodiolus, these mussels do not directly consume food. Instead, they are nourished by symbiotic bacteria that produce energy from methane. Chemosynthetic bivalves are prominent constituents of the fauna of cold seeps and are represented in that setting by five families and this microbial activity produces calcium carbonate, which is deposited on the seafloor and forms a layer of rock. During a period lasting up to decades, these rock formations attract siboglinid tubeworms. Like the mussels, tubeworms rely on chemosynthetic bacteria for survival, true to any symbiotic relationship, a tubeworm also provides for their bacteria by appropriating hydrogen sulfide from the environment
16.
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
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Benthic zone
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The benthic zone is the ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layers. Organisms living in this zone are called benthos, e. g. the benthic community, including crustaceans. The organisms generally live in relationship with the substrate bottom. Examples of contact soil layers include sand bottoms, rocky outcrops, coral, the benthic region of the ocean begins at the shore line and extends downward along the surface of the continental shelf out to sea. The continental shelf is a gently sloping benthic region that extends away from the land mass, at the continental shelf edge, usually about 200 meters deep, the gradient greatly increases and is known as the continental slope. The continental slope drops down to the sea floor. The deep-sea floor is called the plain and is usually about 4,000 meters deep. The ocean floor is not all flat but has submarine ridges, for comparison, the pelagic zone is the descriptive term for the ecological region above the benthos, including the water-column up to the surface. For information on animals that live in the areas of the oceans see aphotic zone. Generally, these life forms that tolerate cool temperatures and low oxygen levels. Benthos are the organisms live in the benthic zone, and are different from those elsewhere in the water column. Many are adapted to live on the substrate, in their habitats they can be considered as dominant creatures, but they are often a source of prey for Carcharhinidae such as the lemon shark. Many organisms adapted to deep-water pressure cannot survive in the parts of the water column. The pressure difference can be very significant, because light does not penetrate very deep into ocean-water, the energy source for the benthic ecosystem is often organic matter from higher up in the water column that drifts down to the depths. This dead and decaying matter sustains the benthic food chain, most organisms in the zone are scavengers or detritivores. Some microorganisms use chemosynthesis to produce biomass, Benthic organisms can be divided into two categories based on whether they make their home on the ocean floor or an inch or two into the ocean floor. Those living on the surface of the floor are known as epifauna. Those who live burrowed into the floor are known as infauna
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High water mark
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A high water mark is a point that represents the maximum rise of a body of water over land. Such a mark is often the result of a flood, but high water marks may reflect an all-time high, knowledge of the high water mark for an area is useful in managing the development of that area, particularly in making preparations for flood surges. High water marks from floods have been measured for planning purposes since at least as far back as the civilizations of ancient Egypt. This may be a flood level sign or other marker. A high water mark is not necessarily an actual physical mark, a landscape marking left by the high water mark of ordinary tidal action may be called a strandline and is typically composed of debris left by high tide. The area at the top of a beach where debris is deposited is an example of this phenomenon, where there are tides, this line is formed by the highest position of the tide, and moves up and down the beach on a fortnightly cycle. The debris is chiefly composed of rotting seaweed, but can include a large amount of litter, either from ships at sea or from sewage outflows. The strandline is an important habitat for a variety of animals, one kind of high water mark is the ordinary high water mark or average high water mark, the high water mark that can be expected to be produced by a body of water in non-flood conditions. The ordinary high water mark may have significance and is often being used to demarcate property boundaries. The ordinary high water mark has also used for other legal demarcations. For the purposes of Section 404 of the Clean Water Act, for the purposes of Sections 9 and 10 of the Rivers and Harbors Act of 1899, the OHWM defines the lateral limits of federal jurisdiction over traditional navigable waters of the US. Likewise, many states use similar definitions of the OHWM for the purposes of their own regulatory programs, in 2016, the Court of Appeals of Indiana ruled that land below the OHWM along Lake Michigan is held by the state in trust for public use. In Australia, the definition of the Mean High Water Mark is. the line of the high tide between the highest tide of each lunar month and the lowest each lunar month averaged over the year. Terrace, benches left by lakes Wash margin
19.
Erosion
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In earth science, erosion is the action of surface processes that remove soil, rock, or dissolved material from one location on the Earths crust, then transport it away to another location. Eroded sediment or solutes may be transported just a few millimetres, the rates at which such processes act control how fast a surface is eroded. Feedbacks are also possible between rates of erosion and the amount of eroded material that is carried by, for example. Processes of erosion that produce sediment or solutes from a place contrast with those of deposition, while erosion is a natural process, human activities have increased by 10-40 times the rate at which erosion is occurring globally. At well-known agriculture sites such as the Appalachian Mountains, intensive farming practices have caused erosion up to 100x the speed of the rate of erosion in the region. Excessive erosion causes both on-site and off-site problems, on-site impacts include decreases in agricultural productivity and ecological collapse, both because of loss of the nutrient-rich upper soil layers. In some cases, the end result is desertification. Off-site effects include sedimentation of waterways and eutrophication of bodies, as well as sediment-related damage to roads. Intensive agriculture, deforestation, roads, anthropogenic climate change and urban sprawl are amongst the most significant human activities in regard to their effect on stimulating erosion, however, there are many prevention and remediation practices that can curtail or limit erosion of vulnerable soils. Rainfall, and the surface runoff which may result from rainfall, produces four types of soil erosion, splash erosion, sheet erosion, rill erosion. Splash erosion is generally seen as the first and least severe stage in the erosion process. In splash erosion, the impact of a falling raindrop creates a crater in the soil. The distance these soil particles travel can be as much as 0.6 m vertically and 1.5 m horizontally on level ground. If the soil is saturated, or if the rate is greater than the rate at which water can infiltrate into the soil. If the runoff has sufficient flow energy, it will transport loosened soil particles down the slope, sheet erosion is the transport of loosened soil particles by overland flow. Rill erosion refers to the development of small, ephemeral concentrated flow paths which function as both sediment source and sediment delivery systems for erosion on hillslopes, generally, where water erosion rates on disturbed upland areas are greatest, rills are active. Flow depths in rills are typically of the order of a few centimetres or less and this means that rills exhibit hydraulic physics very different from water flowing through the deeper, wider channels of streams and rivers. Gully erosion occurs when water accumulates and rapidly flows in narrow channels during or immediately after heavy rains or melting snow
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Landform
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A landform is a natural feature of the solid surface of the Earth or other planetary body. Landforms together make up a given terrain, and their arrangement in the landscape is known as topography, landforms are categorized by characteristic physical attributes such as elevation, slope, orientation, stratification, rock exposure, and soil type. Oceans and continents exemplify the highest-order landforms, landform elements are parts of a high-order landforms that can be further identified and systematically given a cohesive definition such as hill-tops, shoulders, saddles, foreslopes and backslopes. Some generic landform elements including, pits, peaks, channels, ridges, passes, pools, Terrain is the third or vertical dimension of land surface. Topography is the study of terrain, although the word is used as a synonym for relief itself. When relief is described underwater, the term bathymetry is used, in cartography, many different techniques are used to describe relief, including contour lines and TIN. Elementary landforms are the smallest homogeneous divisions of the land surface and these are areas with relatively homogeneous morphometric properties, bounded by lines of discontinuity. A plateau or a hill can be observed at various scales ranging from few hundred meters to hundreds of kilometers, hence, the spatial distribution of landforms is often scale-dependent as is the case for soils and geological strata. A number of factors, ranging from plate tectonics to erosion and deposition, can generate, landforms do not include man-made features, such as canals, ports and many harbors, and geographic features, such as deserts, forests, and grasslands. Many of the terms are not restricted to refer to features of the planet Earth, examples are mountains, hills, polar caps, and valleys, which are found on all of the terrestrial planets. The scientific study of landforms is known as geomorphology, landforms may be extracted from a digital elevation model using some automated techniques where the data has been gathered by modern satellites and stereoscopic aerial surveillance cameras. Until recently, compiling the data found in data sets required time consuming. The most detailed DEMs available are measured directly using LIDAR techniques, geomorphology Land List of landforms Open-geomorphometry project Terrain Open-Geomorphometry Project
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Dune
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In physical geography, a dune is a hill of loose sand built by wind or the flow of water. Dunes occur in different shapes and sizes, formed by interaction with the flow of air or water, most kinds of dunes are longer on the windward side where the sand is pushed up the dune and have a shorter slip face in the lee of the wind. The valley or trough between dunes is called a slack, a dune field is an area covered by extensive sand dunes. Dunes occur, for example, in deserts and along some coasts. Some coastal areas have one or more sets of dunes running parallel to the shoreline directly inland from the beach, in most cases, the dunes are important in protecting the land against potential ravages by storm waves from the sea. Although the most widely distributed dunes are those associated with coastal regions, Dunes can form under the action of water flow, and on sand or gravel beds of rivers, estuaries and the sea-bed. The modern word dune came into English from French c,1790, which in turn came from Middle Dutch dūne. Crescent-shaped mounds are generally wider than they are long, the slipfaces are on the concave sides of the dunes. These dunes form under winds that blow consistently from one direction, some types of crescentic dunes move more quickly over desert surfaces than any other type of dune. A group of dunes moved more than 100 metres per year between 1954 and 1959 in Chinas Ningxia Province, and similar speeds have been recorded in the Western Desert of Egypt. The largest crescentic dunes on Earth, with mean crest-to-crest widths of more than three kilometres, are in Chinas Taklamakan Desert. They may be composed of clay, silt, sand, or gypsum, eroded from the floor or shore, transported up the concave side of the dune. Examples in Australia are up to 6.5 km long,1 km wide and they also occur in southern and West Africa, and in parts of the western United States, especially Texas. Straight or slightly sinuous sand ridges typically much longer than they are wide are known as linear dunes and they may be more than 160 kilometres long. Some linear dunes merge to form Y-shaped compound dunes, many form in bidirectional wind regimes. The long axes of these dunes extend in the resultant direction of sand movement, linear loess hills known as pahas are superficially similar. These hills appear to have formed during the last ice age under permafrost conditions dominated by sparse tundra vegetation. Radially symmetrical, star dunes are pyramidal sand mounds with slipfaces on three or more arms that radiate from the center of the mound
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Littoral drift
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Longshore drift is a geological process that consists of the transportation of sediments along a coast parallel to the shoreline, which is dependent on oblique incoming wind direction. Oblique incoming wind squeezes water along the coast, and so generates a current which moves parallel to the coast. Longshore drift is simply the sediment moved by the longshore current and this current and sediment movement occurs within the surf zone. Beach sand is moved on such oblique wind days, due to the swash and backwash of water on the beach. Breaking surf sends water up the beach at an oblique angle, thus beach sand can move downbeach in a zig zag fashion many tens of meters per day. This process is called beach drift but some regard it as simply part of longshore drift because of the overall movement of sand parallel to the coast. Longshore drift affects numerous sediment sizes as it works in different ways depending on the sediment. Sand is largely affected by the force of breaking waves. There are numerous calculations that take into consideration the factors that produce longshore drift, some of these are, Geological changes, e. g. erosion, backshore changes and emergence of headlands. Change in hydrodynamic forces, e. g. change in wave diffraction in headland, change to hydrodynamic influences, e. g. the influence of new tidal inlets and deltas on drift. Alterations of the sediment budget, e. g. switch of shorelines from drift to swash alignment, the intervention of humans, e. g. cliff protection, groynes, detached breakwaters. The sediment budget takes into consideration sediment sources and sinks within a system, a good example of the sediment budget and longshore drift working together in the coastal system is inlet ebb-tidal shoals, which store sand that has been transported by long shore transport. As well as storing sand these systems may also transfer or by pass sand into other systems, therefore inlet ebb-tidal systems provide a good sources. Long shore occurs in a 90 to 80 degree backwash so it would be presented as an angle with the wave line. This section consists of features of long shore drift that occur on a coast where long shore drift occurs uninterrupted by man-made structures, spits are formed when longshore drift travels past a point where the dominant drift direction and shoreline do not veer in the same direction. As well as dominant drift direction, spits are affected by the strength of wave driven current, wave angle, spits are landforms that have two important features, with the first feature being the region at the up-drift end or proximal end. The proximal end is attached to land and may form a slight “barrier” between the sea and an estuary or lagoon. As an example, the New Brighton spit in Canterbury, New Zealand, was created by longshore drift of sediment from the Waimakariri River to the north and this spit system is currently in equilibrium but undergoes phases of deposition and erosion
23.
Wetland
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A wetland is a land area that is saturated with water, either permanently or seasonally, such that it takes on the characteristics of a distinct ecosystem. The primary factor that distinguishes wetlands from other forms or water bodies is the characteristic vegetation of aquatic plants. Wetlands play a number of roles in the environment, principally water purification, flood control, carbon sink, Wetlands are also considered the most biologically diverse of all ecosystems, serving as home to a wide range of plant and animal life. Wetlands occur naturally on every continent except Antarctica, the largest including the Amazon River basin, the West Siberian Plain, the water found in wetlands can be freshwater, brackish, or saltwater. The main wetland types include swamps, marshes, bogs, and fens, and sub-types include mangrove, carr, pocosin, the UN Millennium Ecosystem Assessment determined that environmental degradation is more prominent within wetland systems than any other ecosystem on Earth. International conservation efforts are being used in conjunction with the development of rapid assessment tools to people about wetland issues. Constructed wetlands can be used to treat municipal and industrial wastewater as well as stormwater runoff and they may also play a role in water-sensitive urban design. A patch of land that develops pools of water after a storm would not be considered a wetland. Wetlands have unique characteristics, they are distinguished from other water bodies or landforms based on their water level. Specifically, wetlands are characterized as having a table that stands at or near the land surface for a long enough period each year to support aquatic plants. A more concise definition is a community composed of hydric soil, Wetlands have also been described as ecotones, providing a transition between dry land and water bodies. In environmental decision-making, there are subsets of definitions that are agreed upon to make regulatory and policy decisions. A wetland is an ecosystem that arises when inundation by water produces soils dominated by anaerobic processes, There are four main kinds of wetlands – marsh, swamp, bog and fen. Some experts also recognize wet meadows and aquatic ecosystems as additional wetland types, the largest wetlands in the world include the swamp forests of the Amazon and the peatlands of Siberia. Under the Ramsar international wetland conservation treaty, wetlands are defined as follows, Article 2.1, may incorporate riparian and coastal zones adjacent to the wetlands, and islands or bodies of marine water deeper than six metres at low tide lying within the wetlands. Although the general definition given above applies around the world, each county, Wetlands generally include swamps, marshes, bogs and similar areas. This definition has been used in the enforcement of the Clean Water Act, some US states, such as Massachusetts and New York, have separate definitions that may differ from the federal governments. It is not uncommon for a wetland to be dry for long portions of the growing season, the most important factor producing wetlands is flooding
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Humidity
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Humidity is the amount of water vapor present in the air. Water vapor is the state of water and is invisible. Humidity indicates the likelihood of precipitation, dew, or fog, higher humidity reduces the effectiveness of sweating in cooling the body by reducing the rate of evaporation of moisture from the skin. This effect is calculated in an index table or humidex. The amount of vapor that is needed to achieve saturation increases as the temperature increases. As the temperature of a parcel of water becomes lower it will not reach the point of saturation without adding or losing water mass. The differences in the amount of vapor in a parcel of air can be quite large. For example, a parcel of air that is near saturation may contain 28 grams of water per cubic meter of air at 30 °C, there are three main measurements of humidity, absolute, relative and specific. Absolute humidity is the content of air expressed in gram per cubic meter. Relative humidity, expressed as a percent, measures the current absolute humidity relative to the maximum for that temperature, specific humidity is the ratio of the mass of water vapor to the total mass of the moist air parcel. Absolute humidity is the mass of water vapor present in a given volume of air. It does not take temperature into consideration, absolute humidity in the atmosphere ranges from near zero to roughly 30 grams per cubic meter when the air is saturated at 30 °C. Absolute humidity is the mass of the vapor, divided by the volume of the air and water vapor mixture. The absolute humidity changes as air temperature or pressure changes and this makes it unsuitable for chemical engineering calculations, e. g. for clothes dryers, where temperature can vary considerably. Mass of water per unit volume as in the equation above is defined as volumetric humidity. Because of the confusion, British Standard BS1339 suggests avoiding the term absolute humidity. Units should always be carefully checked, many humidity charts are given in g/kg or kg/kg, but any mass units may be used. The field concerned with the study of physical and thermodynamic properties of mixtures is named psychrometrics
25.
Microclimate
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A microclimate is a local set of atmospheric conditions that differ from those in the surrounding areas, often with a slight difference but sometimes with a substantial one. The term may refer to areas as small as a few meters or square feet or as large as many square kilometers or square miles. Microclimates can be found in most places, another contributing factor of microclimate is the slope or aspect of an area. The terminology micro-climate first appeared in the 1950s in publications such as Climates in Miniature, microclimates can be used to the advantage of gardeners who carefully choose and position their plants. Cities often raise the temperature by zoning, and a sheltered position can reduce the severity of winter. Roof gardening, however, exposes plants to more extreme temperatures in summer and winter. Tall buildings create their own microclimate, both by overshadowing large areas and by channeling strong winds to ground level, wind effects around tall buildings are assessed as part of a microclimate study. Microclimates can also refer to environments, such as those in a room or other enclosure. Microclimates are commonly created and carefully maintained in museum display and storage environments and this can be done using passive methods, such as silica gel, or with active microclimate control devices. Usually, if the areas have a humid continental climate. The type of soil found in an area can also affect microclimates, for example, soils heavy in clay can act like pavement, moderating the near ground temperature. On the other hand, if soil has many air pockets, then the heat could be trapped underneath the topsoil, two main parameters to define a microclimate within a certain area are temperature and humidity. A source of a drop in temperature and/or humidity can be attributed to different sources or influences, often microclimate is shaped by a conglomerate of different influences and is a subject of microscale meteorology. The well known examples of cold air pool effect are Gstettneralm Sinkhole in Austria, the presence of permafrost close to the surface in a crater creates a unique microclimate environment. As similar as lava tubes can be to caves which are not formed due to volcanic activity the microclimate within the former is different due to dominant presence of basalt, lava tubes and basaltic caves are important astrobiological targets on Earth and Mars. Artificial reservoirs as well as natural ones create microclimates and often influence the climate as well. Northern California above the Bay Area is also known for microclimates with significant differences of temperatures. Even as far north as the Klamath River valley around the 41st parallel north between Willow Creek and Eureka averages such temperatures, which is hot for such northerly areas
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Noun
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A noun is a word that functions as the name of some specific thing or set of things, such as living creatures, objects, places, actions, qualities, states of existence, or ideas. Linguistically, a noun is a member of a large, open part of whose members can occur as the main word in the subject of a clause. Lexical categories are defined in terms of the ways in which their members combine with other kinds of expressions, the syntactic rules for nouns differ from language to language. In English, nouns are words which can occur with articles and attributive adjectives. Word classes were described by Sanskrit grammarians from at least the 5th century BC, in Yāskas Nirukta, the noun is one of the four main categories of words defined. The Ancient Greek equivalent was ónoma, referred to by Plato in the Cratylus dialog, the term used in Latin grammar was nōmen. All of these terms for noun were also words meaning name, the English word noun is derived from the Latin term, through the Anglo-Norman noun. The word classes were defined partly by the forms that they take. In Sanskrit, Greek and Latin, for example, nouns are categorized by gender and inflected for case, because adjectives share these three grammatical categories, adjectives are placed in the same class as nouns. Similarly, the Latin nōmen includes both nouns and adjectives, as originally did the English word noun, the two types being distinguished as nouns substantive and nouns adjective, many European languages use a cognate of the word substantive as the basic term for noun. Nouns in the dictionaries of languages are demarked by the abbreviation s. or sb. instead of n. which may be used for proper nouns or neuter nouns instead. In English, some authors use the word substantive to refer to a class that includes both nouns and noun phrases. It can also be used as a counterpart to attributive when distinguishing between a noun being used as the head of a phrase and a noun being used as a noun adjunct. For example, the knee can be said to be used substantively in my knee hurts. Nouns have sometimes been defined in terms of the categories to which they are subject. Such definitions tend to be language-specific, since nouns do not have the categories in all languages. Nouns are frequently defined, particularly in contexts, in terms of their semantic properties. Nouns are described as words that refer to a person, place, thing, event, substance, quality, quantity, however this type of definition has been criticized by contemporary linguists as being uninformative
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Adjective
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In linguistics, an adjective is a describing word, the main syntactic role of which is to qualify a noun or noun phrase, giving more information about the object signified. Adjectives are one of the English parts of speech, although historically they were classed together with the nouns, certain words that were traditionally considered to be adjectives, including the, this, my, etc. are today usually classed separately, as determiners. Adjective comes from Latin adjectīvum additional, a calque of Ancient Greek, in the grammatical tradition of Latin and Greek, because adjectives were inflected for gender, number, and case like nouns, they were considered a subtype of noun. The words that are typically called nouns were then called substantive nouns. The terms noun substantive and noun adjective were formerly used in English, in English, attributive adjectives usually precede their nouns in simple phrases, but often follow their nouns when the adjective is modified or qualified by a phrase acting as an adverb. For example, I saw three kids, and I saw three kids happy enough to jump up and down with glee. Predicative adjectives are linked via a copula or other linking mechanism to the noun or pronoun they modify, for example, happy is an adjective in they are happy. Nominal adjectives act almost as nouns, One way this can happen is if a noun is elided and an attributive adjective is left behind. In the sentence, I read two books to them, he preferred the sad book, but she preferred the happy, happy is a nominal adjective, short for happy one or happy book. Another way this can happen is in phrases like out with the old, in with the new, where the old means, that which is old or all that is old, and similarly with the new. In such cases, the adjective functions either as a noun or as a plural count noun, as in The meek shall inherit the Earth. Adjectives feature as a part of speech in most languages, in some languages, the words that serve the semantic function of adjectives may be categorized together with some other class, such as nouns or verbs. Such an analysis is possible for the grammar of Standard Chinese, different languages do not always use adjectives in exactly the same situations. For example, where English uses to be hungry, Dutch and French use honger hebben, similarly, where Hebrew uses the adjective זקוק zaqūq, English uses the verb to need. In languages which have adjectives as a class, they are usually an open class. However, Bantu languages are known for having only a small closed class of adjectives. Many languages, including English, distinguish between adjectives, which qualify nouns and pronouns, and adverbs, which mainly modify verbs, adjectives, not all languages have exactly this distinction and many languages, including English, have words that can function as both. For example, in English fast is an adjective in a fast car, in Dutch and German, adjectives and adverbs are usually identical in form and many grammarians do not make the distinction, but patterns of inflection can suggest a difference, Eine kluge neue Idee
28.
Oceanography
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Oceanography, also known as oceanology, is the study of the physical and the biological aspects of the ocean. Paleoceanography studies the history of the oceans in the geologic past, humans first acquired knowledge of the waves and currents of the seas and oceans in pre-historic times. Observations on tides were recorded by Aristotle and Strabo, early exploration of the oceans was primarily for cartography and mainly limited to its surfaces and of the animals that fishermen brought up in nets, though depth soundings by lead line were taken. Although Juan Ponce de León in 1513 first identified the Gulf Stream, Franklin measured water temperatures during several Atlantic crossings and correctly explained the Gulf Streams cause. Franklin and Timothy Folger printed the first map of the Gulf Stream in 1769-1770, information on the currents of the Pacific Ocean was gathered by explorers of the late 18th century, including James Cook and Louis Antoine de Bougainville. James Rennell wrote the first scientific textbooks on oceanography, detailing the current flows of the Atlantic, during a voyage around the Cape of Good Hope in 1777, he mapped the banks and currents at the Lagullas. He was also the first to understand the nature of the intermittent current near the Isles of Scilly, Robert FitzRoy published a four-volume report of the Beagles three voyages. In 1841–1842 Edward Forbes undertook dredging in the Aegean Sea that founded marine ecology, the first superintendent of the United States Naval Observatory, Matthew Fontaine Maury devoted his time to the study of marine meteorology, navigation, and charting prevailing winds and currents. His 1855 textbook Physical Geography of the Sea was one of the first comprehensive oceanography studies, many nations sent oceanographic observations to Maury at the Naval Observatory, where he and his colleagues evaluated the information and distributed the results worldwide. Despite all this, human knowledge of the oceans remained confined to the topmost few fathoms of the water, almost nothing was known of the ocean depths. The Royal Navys efforts to all of the worlds coastlines in the mid-19th century reinforced the vague idea that most of the ocean was very deep. As exploration ignited both popular and scientific interest in the regions and Africa, so too did the mysteries of the unexplored oceans. The seminal event in the founding of the science of oceanography was the 1872-76 Challenger expedition. As the first true oceanographic cruise, this laid the groundwork for an entire academic. In response to a recommendation from the Royal Society, The British Government announced in 1871 an expedition to explore worlds oceans, charles Wyville Thompson and Sir John Murray launched the Challenger expedition. The Challenger, leased from the Royal Navy, was modified for scientific work, under the scientific supervision of Thomson, Challenger travelled nearly 70,000 nautical miles surveying and exploring. On her journey circumnavigating the globe,492 deep sea soundings,133 bottom dredges,151 open water trawls and 263 serial water temperature observations were taken, around 4,700 new species of marine life were discovered. The result was the Report Of The Scientific Results of the Exploring Voyage of H. M. S, Murray, who supervised the publication, described the report as the greatest advance in the knowledge of our planet since the celebrated discoveries of the fifteenth and sixteenth centuries
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Marine biology
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Marine biology is the scientific study of organisms in the sea. Marine biology differs from marine ecology as marine ecology is focused on how organisms interact with each other, a large proportion of all life on Earth lives in the ocean. The exact size of this proportion is unknown, since many ocean species are still to be discovered. The ocean is a complex three-dimensional world covering approximately 71% of the Earths surface, the organisms studied range from microscopic phytoplankton and zooplankton to huge cetaceans 30 meters in length. Marine life is a vast resource, providing food, medicine, at a fundamental level, marine life helps determine the very nature of our planet. Marine organisms contribute significantly to the cycle, and are involved in the regulation of the Earths climate. Shorelines are in part shaped and protected by marine life, many species are economically important to humans, including both finfish and shellfish. It is also becoming understood that the well-being of marine organisms, the human body of knowledge regarding the relationship between life in the sea and important cycles is rapidly growing, with new discoveries being made nearly every day. These cycles include those of matter and of air, large areas beneath the ocean surface still remain effectively unexplored. The study of marine biology dates back to Aristotle, who made observations of life in the sea around Lesbos. In 1768, Samuel Gottlieb Gmelin published the Historia Fucorum, the first work dedicated to marine algae and it included elaborate illustrations of seaweed and marine algae on folded leaves. The British naturalist Edward Forbes is generally regarded as the founder of the science of marine biology, the pace of oceanographic and marine biology studies quickly accelerated during the course of the 19th century. The observations made in the first studies of marine biology fueled the age of discovery, during this time, a vast amount of knowledge was gained about the life that exists in the oceans of the world. Many voyages contributed significantly to this pool of knowledge, among the most significant were the voyages of the HMS Beagle where Charles Darwin came up with his theories of evolution and on the formation of coral reefs. The creation of laboratories was important because it allowed marine biologists to conduct research. The oldest marine laboratory in the world, Station biologique de Roscoff, was established in France in 1872, in the United States, the Scripps Institution of Oceanography dates back to 1903, while the prominent Woods Hole Oceanographic Institute was founded in 1930. As inhabitants of the largest environment on Earth, microbial marine systems drive changes in every global system, microbes are responsible for virtually all the photosynthesis that occurs in the ocean, as well as the cycling of carbon, nitrogen, phosphorus and other nutrients and trace elements. Microscopic life undersea is incredibly diverse and still poorly understood, for example, the role of viruses in marine ecosystems is barely being explored even in the beginning of the 21st century
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Littoral zone
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The littoral zone is the part of a sea, lake or river that is close to the shore. In coastal environments the littoral zone extends from the water mark. It always includes this intertidal zone and is used to mean the same as the intertidal zone. However, the meaning of littoral zone can extend well beyond the intertidal zone, what is regarded as the full extent of the littoral zone, and the way the littoral zone is divided into subregions, varies in different contexts. The use of the term varies from one part of the world to another. For example, military commanders speak of the littoral in ways that are different from marine biologists. The adjacency of water gives a number of characteristics to littoral regions. The erosive power of water results in particular types of landforms, such as sand dunes, the natural movement of the littoral along the coast is called the littoral drift. Biologically, the availability of water enables a greater variety of plant and animal life. In addition, the local humidity due to evaporation usually creates a microclimate supporting unique types of organisms. The word littoral is used both as a noun and an adjective and it derives from the Latin noun litus, litoris, meaning shore. In oceanography and marine biology, the idea of the zone is extended roughly to the edge of the continental shelf. Starting from the shoreline, the zone begins at the spray region just above the high tide mark. From here, it moves to the region between the high and low water marks, and then out as far as the edge of the continental shelf. These three subregions are called, in order, the zone, the eulittoral zone and the sublittoral zone. The supralittoral zone is the area above the high tide line that is regularly splashed. Seawater penetrates these elevated areas only during storms with high tides, organisms here must cope also with exposure to fresh water from rain, cold, heat and predation by land animals and seabirds. At the top of this area, patches of dark lichens can appear as crusts on rocks, some types of periwinkles, Neritidae and detritus feeding Isopoda commonly inhabit the lower supralittoral
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Predation
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In an ecosystem, predation is a biological interaction where a predator feeds on its prey. Predators may or may not kill their prey prior to feeding on it, but the act of predation often results in the death of the prey, thus predation is often, though not always, carnivory. Other categories of consumption are herbivory, fungivory, and detritivory, all of these are consumer-resource systems. It can often be difficult to separate various types of feeding behaviors. For example, some parasites prey on their host and then lay their eggs on it, for their offspring to feed on it while it continues to live, the key characteristic of predation is the predators direct impact on the prey population. Selective pressures imposed on one another leads to an evolutionary arms race between prey and predator, resulting in various antipredator adaptations. Ways of classifying predation include grouping by trophic level or diet, by specialization, Predators can be classified by their interactions with their prey. Two factors are considered here, how close the predator and prey are, and whether the prey is killed by the predator. A true predator is one that kills and eats another living thing, Predators may hunt actively for prey in pursuit predation, or sit and wait for prey to approach within striking distance, as in ambush predators. Some predation entails venom that subdues a prey before the predator ingests it, as in the box jellyfish, or disables it, in some cases, the venom contributes to the digestion of the prey, as in rattlesnakes and some spiders. In contrast, baleen whales eat millions of microscopic plankton at once, seed and egg predation are true predation, as seeds and eggs are potential organisms. Predators need not eat prey entirely, for example, some predators cannot digest bones, some may eat only part of an organism, but still consistently cause its death. Grazing organisms do not often kill their prey, while some herbivores like zooplankton live on unicellular phytoplankton and therefore, by the individualized nature of the organism, kill their prey, many others only eat a small part of the plant. Grazing livestock may pull some grass out at the roots, but most is simply grazed upon, kelp is frequently grazed in subtidal kelp forests, but regrows at the base of the blade continuously to cope with browsing pressure. Animals may also be grazed upon, female mosquitos land on hosts briefly to gain sufficient proteins for the development of their offspring, starfish may be grazed on, being capable of regenerating lost arms. Parasites can at times be difficult to distinguish from grazers and their feeding behavior is similar in many ways, however they are noted for their close association with their host species. This close living arrangement may be described by the symbiosis, living together. Parasitic organisms range from the mistletoe, a parasitic plant
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Lichen
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A lichen is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi in a symbiotic relationship. The combined lichen has properties different from those of its component organisms, Lichens come in many colours, sizes, and forms. The properties are sometimes plant-like, but lichens are not plants, Lichens may have tiny, leafless branches, flat leaf-like structures, flakes that lie on the surface like peeling paint, or other growth forms. A macrolichen is a lichen that is either bush-like or leafy, here, macro and micro do not refer to size, but to the growth form. Common names for lichens may contain the word moss, and lichens may superficially look like and grow with mosses, Lichens do not have roots that absorb water and nutrients as plants do, but like plants, they produce their own food by photosynthesis. When they grow on plants, they do not live as parasites, Lichens occur from sea level to high alpine elevations, in many environmental conditions, and can grow on almost any surface. Lichens are abundant growing on bark, leaves, mosses, on other lichens and they grow on rock, walls, gravestones, roofs, exposed soil surfaces, and in the soil as part of a biological soil crust. Different kinds of lichens have adapted to survive in some of the most extreme environments on Earth, arctic tundra, hot dry deserts, rocky coasts and they can even live inside solid rock, growing between the grains. It is estimated that 6% of Earths land surface is covered by lichen, there are about 20,000 known species of lichens. Some lichens have lost the ability to reproduce sexually, yet continue to speciate, Lichens may be long-lived, with some considered to be among the oldest living things. They are among the first living things to grow on fresh rock exposed after an event such as a landslide, the long life-span and slow and regular growth rate of some lichens can be used to date events. In American English, lichen is pronounced the same as the verb liken, in British English, both this pronunciation and one rhyming with kitchen /ˈlɪtʃən/) are used. Lichens grow in a range of shapes and forms. The shape of a lichen is determined by the organization of the fungal filaments. The nonreproductive tissues, or vegetative body parts, is called the thallus, Lichens are grouped by thallus type, since the thallus is usually the most visually prominent part of the lichen. Thallus growth forms typically correspond to a few basic internal structure types, Common names for lichens often come from a growth form or color that is typical of a lichen genus. When a crustose lichen gets old, the center may start to crack up like old-dried paint, old-broken asphalt paving and this is called being rimose or areolate, and the island pieces separated by the cracks are called areolas. The areolas appear separated, but are connected by an underlying prothallus or hypothallus, when a crustose lichen grows from a center and appears to radiate out, it is called crustose placodioid
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Common periwinkle
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The common periwinkle or winkle is a species of small edible sea snail, a marine gastropod mollusc that has gills and an operculum, and is classified within the family Littorinidae, the periwinkles. This is a robust intertidal species with a dark and sometimes banded shell and it is native to the rocky shores of the northeastern, and introduced to the northwestern, Atlantic Ocean. There is another known as small periwinkle or Melarhaphe neritoides that looks similar. The shell is ovate, thick, and sharply pointed except when eroded. The shell contains six to seven whorls with fine threads. The color is variable from grayish to gray-brown, often with dark spiral bands, the base of the columella is white. The white outer lip is sometimes checkered with brown patches, the inside of the shell has a chocolate-brown color. The width of the ranges from 10 to 12 mm at maturity. Shell height can reach up to 30 mm,43 mm or 52 mm, as a result of its robust nature, Littorina littorea can be highly variable in phenotype with several different morphs present. Its phenotypic variations may be indicative of an event, as opposed to phenotypic plasticity. This is of importance to evolutionary biology, as it presents the possible opportunity to view a transitional phase in the evolutionary life of an organism. Measuring the shell from the end of the aperture to the apex reveals the length of the snail, turning the shell over with the aperture flat on a surface and measuring vertically reveals the height of the snail. These measurements can be using a caliper. Common periwinkles are native to the coasts of the Atlantic Ocean, including northern Spain, France, England, Scotland, Ireland, Scandinavia. There have been more than 14000 observations made available as a dataset at the Global Biodiversity Information Facility - Littorina Littorea, more distribution information can also be found at Ocean Biographic Information System - Littorina Littorea. The NBN Gateway - Littorina Littorea has a distribution map over the UK. Common periwinkles have been introduced to the Atlantic coast of North America and this species is also found on the west coast of the United States, from Washington to California. The first recorded sighting in the East was in 1840 in the Gulf of St. Lawrence and it is now abundant on rocky shores from New Jersey northward to Newfoundland
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Neritidae
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The family Neritidae includes marine genera such as Nerita, marine and freshwater genera such as Neritina, and freshwater and brackish water genera such as Theodoxus. The common name nerite as well as the family name Neritidae and the genus name Nerita, are derived from the name of Nerites, Neritidae live primarily in the southern hemisphere, but there are some exceptions, such as a genus Theodoxus or Bathynerita naticoidea. Contributions to the morphology of the group Neritacea of aspidobranch gastropods, proceedings of the Zoological Society of London 1908, 810-887
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Isopoda
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Isopoda is an order of crustaceans that includes woodlice and their relatives. Isopods live in the sea, in water, or on land. All have rigid, segmented exoskeletons and most are grayish or whitish in color and they have two pairs of antennae, seven pairs of jointed limbs on the thorax, and five pairs of branching appendages on the abdomen that are used in respiration. Females brood their young in a pouch under their thorax, aquatic species mostly live on the seabed or bottom of freshwater bodies of water, but some more derived taxa can swim for a short distance. Terrestrial forms move around by crawling and tend to be found in cool, some species are able to roll themselves into a ball to conserve moisture or as a defence mechanism. There are over 10,000 species of isopod worldwide, with around 4,500 species found in environments, mostly on the seabed,500 species in fresh water. The order is divided into eleven suborders, the fossil record of isopods dates back to the Carboniferous period, at least 300 million years ago, when isopods lived in shallow seas. The name Isopoda is derived from the Greek roots ἴσος and πούς, classified within the arthropods, isopods have a chitinous exoskeleton and jointed limbs. Isopods are typically flattened dorsoventrally, although many species deviate from this rule, particularly parasitic forms, and their colour may vary, from grey to white, or in some cases red, green, or brown. Isopods vary in size, ranging from some Microcerberidae species of just 0.3 mm to the deep sea Bathynomus spp. of nearly 50 cm, isopods lack an obvious carapace, which is reduced to a cephalic shield covering only the head. This means that the structures, which in other related groups are protected by the carapace, are instead found on specialised limbs on the abdomen. The dorsal surface of the animal is covered by a series of overlapping, the isopod body plan consists of a head, a thorax with eight segments, and an abdomen with six segments, some of which may be fused. The head is fused with the first segment of the thorax to form the cephalon, there are two pairs of unbranched antennae, the first pair being vestigial in land-dwelling species. The eyes are compound and unstalked and the include a pair of maxillipeds. The seven free segments of the thorax each bear a pair of unbranched pereopods, in most species these are used for locomotion and are of much the same size, morphology and orientation, giving the order its name Isopoda, from the Greek equal foot. In a few species, the front pair are modified into gnathopods with clawed, the pereopods are not used in respiration, as are the equivalent limbs in amphipods, but the coxae are fused to the tergites to form epimera. In mature females, some or all of the limbs have appendages known as oostegites which fold underneath the thorax, in males, the gonopores are on the ventral surface of segment eight and in the females, they are in a similar position on segment six. One or more of the segments, starting with the sixth segment, is fused to the telson to form a rigid pleotelson
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Barnacle
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A barnacle is a type of arthropod constituting the infraclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters and they are sessile suspension feeders, and have two nektonic larval stages. Around 1,220 barnacle species are currently known, the name Cirripedia is Latin, meaning curl-footed. Barnacles are encrusters, attaching themselves permanently to a hard substrate, the most common, acorn barnacles, are sessile, growing their shells directly onto the substrate. The order Pedunculata attach themselves by means of a stalk, free-living barnacles are attached to the substratum by cement glands that form the base of the first pair of antennae, in effect, the animal is fixed upside down by means of its forehead. In some barnacles, the cement glands are fixed to a long, muscular stalk, a ring of plates surrounds the body, homologous with the carapace of other crustaceans. These consist of the rostrum, two plates, two carinolaterals, and a carina. In sessile barnacles, the apex of the ring of plates is covered by an operculum, the plates are held together by various means, depending on species, in some cases being solidly fused. Inside the carapace, the lies on its back, with its limbs projecting upwards. Segmentation is usually indistinct, and the body is more or less divided between the head and thorax, with little, if any, abdomen. Adult barnacles have few appendages on their heads, with only a single, vestigial pair of antennae, attached to the cement gland. The six pairs of limbs are referred to as cirri. Barnacles have no heart, although a sinus close to the esophagus performs similar function. The blood vascular system is minimal, similarly, they have no gills, absorbing oxygen from the water through their limbs and the inner membrane of their carapaces. The excretory organs of barnacles are maxillary glands, the main sense of barnacles appears to be touch, with the hairs on the limbs being especially sensitive. The adult also has an eye, although this is probably only capable of sensing the difference between light and dark. This eye is derived from the naupliar eye. Barnacles have two larval stages, the nauplius and the cyprid, before developing into a mature adult
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Intertidal ecology
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Intertidal ecology is the study of intertidal ecosystems, where organisms live between the low and high tide lines. At low tide, the intertidal is exposed whereas at high tide, organisms living in this zone have a highly variable and often hostile environment, and have evolved various adaptations to cope with and even exploit these conditions. One easily visible feature of communities is vertical zonation, where the community is divided into distinct vertical bands of specific species going up the shore. In some places Marine Protected Areas have been established to protect these areas, Intertidal habitats can be characterized as having either hard or soft bottoms substrates. Rocky intertidal communities occur on rocky shores, such as headlands, cobble beaches and their degree of exposure may be calculated using the Ballantine Scale. Soft-sediment habitats include sandy beaches, and intertidal wetlands and these habitats differ in levels of abiotic, or non-living, environmental factors. Rocky shores tend to have wave action, requiring adaptations allowing the inhabitants to cling tightly to the rocks. Soft-bottom habitats are protected from large waves but tend to have more variable salinity levels. They also offer a third habitable dimension—depth—thus, many soft-sediment inhabitants are adapted for burrowing, because intertidal organisms endure regular periods of immersion and emersion, they essentially live both underwater and on land and must be adapted to a large range of climatic conditions. This gradient of climate with tide height leads to patterns of intertidal zonation and these adaptations may be behavioral, morphological, or physiological. In addition, such adaptations generally cost the organism in terms of energy, Intertidal organisms, especially those in the high intertidal, must cope with a large range of temperatures. While they are underwater, temperatures may vary by a few degrees over the year. However, at low tide, temperatures may dip to below freezing or may become scaldingly hot, Many mobile organisms, such as snails and crabs, avoid temperature fluctuations by crawling around and searching for food at high tide and hiding in cool, moist refuges at low tide. Besides simply living at lower heights, non-motile organisms may be more dependent on coping mechanisms. Intertidal organisms are especially prone to desiccation during periods of emersion. Again, mobile organisms avoid desiccation in the way as they avoid extreme temperatures, by hunkering down in mild. Many intertidal organisms, including Littorina snails, prevent water loss by having waterproof outer surfaces, pulling completely into their shells, limpets do not use such a sealing plate but occupy a home-scar to which they seal the lower edge of their flattened conical shell using a grinding action. They return to this home-scar after each grazing excursion, typically just before emersion, on soft rocks, these scars are quite obvious
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Physical oceanography
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Physical oceanography is the study of physical conditions and physical processes within the ocean, especially the motions and physical properties of ocean waters. Physical oceanography is one of several sub-domains into which oceanography is divided, others include biological, chemical and geological oceanography. Physical oceanography may be subdivided into descriptive and dynamical physical oceanography, descriptive physical oceanography seeks to research the ocean through observations and complex numerical models, which describe the fluid motions as precise as possible. Dynamical physical oceanography focuses primarily upon the processes that govern the motion of fluids with emphasis upon theoretical research and these are part of the large field of Geophysical Fluid Dynamics that is shared together with meteorology. The fundamental role of the oceans in shaping Earth is acknowledged by ecologists, geologists, meteorologists, climatologists, an Earth without oceans would truly be unrecognizable. Roughly 97% of the water is in its oceans. The tremendous heat capacity of the oceans moderates the planets climate, the oceans influence extends even to the composition of volcanic rocks through seafloor metamorphism, as well as to that of volcanic gases and magmas created at subduction zones. Though this apparent discrepancy is great, for land and sea, the respective extremes such as mountains and trenches are rare. Because the vast majority of the oceans volume is deep water. The same percentage falls in a salinity range between 34–35 ppt, there is still quite a bit of variation, however. Surface temperatures can range from below freezing near the poles to 35 °C in restricted tropical seas, in terms of temperature, the oceans layers are highly latitude-dependent, the thermocline is pronounced in the tropics, but nonexistent in polar waters. The halocline usually lies near the surface, where evaporation raises salinity in the tropics and these variations of salinity and temperature with depth change the density of the seawater, creating the pycnocline. Energy for the ocean circulation comes from solar radiation and gravitational energy from the sun, perhaps three quarters of this heat is carried in the atmosphere, the rest is carried in the ocean. The atmosphere is heated from below, which leads to convection, by contrast the ocean is heated from above, which tends to suppress convection. Instead ocean deep water is formed in regions where cold salty waters sink in fairly restricted areas. This is the beginning of the thermohaline circulation, oceanic currents are largely driven by the surface wind stress, hence the large-scale atmospheric circulation is important to understanding the ocean circulation. The Hadley circulation leads to Easterly winds in the tropics and Westerlies in mid-latitudes and this leads to slow equatorward flow throughout most of a subtropical ocean basin. The return flow occurs in an intense, narrow, poleward western boundary current, like the atmosphere, the ocean is far wider than it is deep, and hence horizontal motion is in general much faster than vertical motion
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Internal wave
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Internal waves are gravity waves that oscillate within a fluid medium, rather than on its surface. To exist, the fluid must be stratified, the density must decrease continuously or discontinuously with depth/height due to changes, for example, If the density changes continuously, the waves can propagate vertically as well as horizontally through the fluid. Internal waves, also called gravity waves, go by many other names depending upon the fluid stratification, generation mechanism, amplitude. If propagating horizontally along an interface where the density decreases with height. If the interfacial waves are large amplitude they are called solitary waves or internal solitons. If moving vertically through the atmosphere where substantial changes in air density influences their dynamics, If generated by flow over topography, they are called Lee waves or mountain waves. If the mountain waves break aloft, they can result in strong winds at the ground known as Chinook winds or Foehn winds. If generated in the ocean by tidal flow over submarine ridges or the continental shelf, If they evolve slowly compared to the Earths rotational frequency so that their dynamics are influenced by the Coriolis effect, they are called inertia gravity waves or, simply, inertial waves. Internal waves are usually distinguished from Rossby waves, which are influenced by the change of Coriolis frequency with latitude. An internal wave can readily be observed in the kitchen by slowly tilting back, clouds that reveal internal waves launched by flow over hills are called lenticular clouds because of their lens-like appearance. Less dramatically, a train of waves can be visualized by rippled cloud patterns described as herringbone sky or mackerel sky. The outflow of air from a thunderstorm can launch large amplitude internal solitary waves at an atmospheric inversion. In northern Australia, these result in Morning Glory clouds, used by some daredevils to glide along like a surfer riding an ocean wave, satellites over Australia and elsewhere reveal these waves can span many hundreds of kilometers. According to Archimedes principle, the weight of an object is reduced by the weight of fluid it displaces. This holds for a parcel of density ρ surrounded by an ambient fluid of density ρ0. Its weight per volume is g, in which g is the acceleration of gravity. Dividing by a density, ρ00, gives the definition of the reduced gravity. Because water is more dense than air, the displacement of water by air from a surface gravity wave feels nearly the full force of gravity
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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
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Primary production
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In ecology, primary production is the synthesis of organic compounds from atmospheric or aqueous carbon dioxide. Almost all life on Earth relies directly or indirectly on primary production, the organisms responsible for primary production are known as primary producers or autotrophs, and form the base of the food chain. In terrestrial ecoregions, these are mainly plants, while in aquatic ecoregions algae predominate in this role, ecologists distinguish primary production as either net or gross, the former accounting for losses to processes such as cellular respiration, the latter not. Primary production is the production of energy in organic compounds by living organisms. The main source of energy is sunlight but a minute fraction of primary production is driven by lithotrophic organisms using the chemical energy of inorganic molecules. Regardless of its source, this energy is used to complex organic molecules from simpler inorganic compounds such as carbon dioxide. Consumption of primary producers by heterotrophic organisms, such as animals, then transfers these organic molecules up the food web, gross primary production is the amount of chemical energy as biomass that primary producers create in a given length of time. Some fraction of this energy is used by primary producers for cellular respiration. The remaining fixed energy is referred to as net primary production, some net primary production goes toward growth and reproduction of primary producers, while some is consumed by herbivores. Both gross and net primary production are in units of mass per area per unit time interval. In terrestrial ecosystems, mass of carbon per area per year is most often used as the unit of measurement. On the land, almost all production is now performed by vascular plants, with a small fraction coming from algae and non-vascular plants such as mosses. Before the evolution of plants, non-vascular plants likely played a more significant role. Primary production on land is a function of many factors, but principally local hydrology, while plants cover much of the Earths surface, they are strongly curtailed wherever temperatures are too extreme or where necessary plant resources are limiting, such as deserts or polar regions. Water is consumed in plants by the processes of photosynthesis and transpiration, the latter process is driven by the evaporation of water from the leaves of plants. Transpiration allows plants to transport water and mineral nutrients from the soil to growth regions, diffusion of water vapour out of a leaf, the force that drives transpiration, is regulated by structures known as stomata. These structure also regulate the diffusion of carbon dioxide from the atmosphere into the leaf, certain plants use alternative forms of photosynthesis, called Crassulacean acid metabolism and C4. In a reversal of the pattern on land, in the oceans, almost all photosynthesis is performed by algae, with a small fraction contributed by vascular plants, algae encompass a diverse range of organisms, ranging from single floating cells to attached seaweeds
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Coral
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Corals are marine invertebrates in the class Anthozoa of phylum Cnidaria. They typically live in colonies of many identical individual polyps. The group includes the important reef builders that inhabit tropical oceans, a coral group is a colony of myriad genetically identical polyps. Each polyp is an animal typically only a few millimeters in diameter. A set of tentacles surround a central mouth opening, an exoskeleton is excreted near the base. Over many generations, the colony creates a large skeleton that is characteristic of the species. Individual heads grow by reproduction of polyps. Corals also breed sexually by spawning, polyps of the same species release gametes simultaneously over a period of one to several nights around a full moon and these are commonly known as zooxanthellae and the corals that contain them are zooxanthellate corals. Such corals require sunlight and grow in clear, shallow water, other corals do not rely on zooxanthellae and can live in much deeper water, with the cold-water genus Lophelia surviving as deep as 3,000 metres. Some have been found on the Darwin Mounds, north-west of Cape Wrath, Corals have also been found as far north as off the coast of Washington State and the Aleutian Islands. In his Scala Naturae, Aristotle classified corals as zoophyta, animals that had characteristics of plants and were therefore hypothetically in between animals and plants, the Persian polymath Al-Biruni classified sponges and corals as animals, arguing that they respond to touch. The phylogeny of Anthozoans is not clearly understood and a number of different models have been proposed, within the Hexacorallia, the sea anemones, coral anemones and stony corals may constitute a monophyletic grouping united by their eight-fold symmetry and cnidocyte trait. The Octocorallia appears to be monophyletic, and primitive members of this group may have been stolonate, the cladogram presented here comes from a 2014 study by Stampar et al. which was based on the divergence of mitochondrial DNA within the group and on nuclear markers. Corals are classified in the class Anthozoa of the phylum Cnidaria and they are divided into three subclasses, Hexacorallia, Octocorallia, and Ceriantharia. The Hexacorallia include the stony corals, the sea anemones and the zoanthids and these groups have polyps that generally have 6-fold symmetry. The Octocorallia include blue coral, soft corals, sea pens and these groups have polyps with 8-fold symmetry, each polyp having eight tentacles and eight mesenteries. Fire corals are not true corals, being in the order Anthomedusa of the class Hydrozoa, Corals are sessile animals in the class Anthozoa and differ from most other cnidarians in not having a medusa stage in their life cycle. The body unit of the animal is a polyp, most corals are colonial, the initial polyp budding to produce another and the colony gradually developing from this small start
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Sessility (motility)
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In biology, sessility refers to organisms that do not possess a means of self-locomotion and are normally immobile. This is distinct from the meaning of sessility which refers to an organism or biological structure attached directly by its base without a stalk. Sessile organisms can move through outside sources but are permanently attached to something. Organisms such as corals lay down their own substrate from which they grow, other organisms grow from a solid such as a rock, dead tree trunk, or a manmade object such as a buoy or ships hull. Sessile animals typically have a phase in their development. Sponges have a larval stage, which becomes sessile at maturity. In contrast, many jellyfish develop as sessile polyps early in their life cycle, in the case of the cochineal, it is in the nymph stage that the cochineal disperses. The juveniles move to a spot and produce long wax filaments. Later they move to the edge of the cactus pad where the wind catches the wax filaments, many sessile animals, including sponges, corals and hydra, are capable of asexual reproduction in situ by the process of budding. Sessile organisms such as barnacles and tunicates need some mechanism to move their young into new territory and this is why the most widely accepted theory explaining the evolution of a larval stage is the need for long-distance dispersal ability. This allows for faster reproduction and better protection from predators, the circalittoral zone of coastal environments and biomes are dominated by sessile organisms such as oysters. Carbonate platforms grow due to the buildup of skeletal remains of organisms, usually microorganisms. In anatomy and botany, sessility refers to an organism or biological structure that has no peduncle or stalk, a sessile structure has no stalk
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Oyster
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Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species the valves are highly calcified, and many are somewhat irregular in shape, many, but not all, oysters are in the superfamily Ostreoidea. Some kinds of oysters are consumed by humans, cooked or raw. Some kinds of oysters are harvested for the pearl produced within the mantle. Windowpane oysters are harvested for their translucent shells, which are used to various kinds of decorative objects. True oysters are members of the family Ostreidae and this family includes the edible oysters, which mainly belong to the genera Ostrea, Crassostrea, Ostreola, and Saccostrea. Examples include the Belon oyster, eastern oyster, Olympia oyster, Pacific oyster, almost all shell-bearing mollusks can secrete pearls, yet most are not very valuable. Pearl oysters are not closely related to oysters, being members of a distinct family. Both cultured pearls and natural pearls can be extracted from pearl oysters, though other molluscs, such as the freshwater mussels, the largest pearl-bearing oyster is the marine Pinctada maxima, which is roughly the size of a dinner plate. Not all individual oysters produce pearls naturally, in fact, in a harvest of two and a half tons of oysters, only three to four oysters produce what commercial buyers consider to be absolute perfect pearls. In nature, pearl oysters produce pearls by covering a minute invasive object with nacre, over the years, the irritating object is covered with enough layers of nacre to become a pearl. The many different types, colours and shapes of pearls depend on the pigment of the nacre. Pearl farmers can culture a pearl by placing a nucleus, usually a piece of polished mussel shell, in three to seven years, the oyster can produce a perfect pearl. These pearls are not as valuable as natural pearls, but look exactly the same, in fact, since the beginning of the 20th century, when several researchers discovered how to produce artificial pearls, the cultured pearl market has far outgrown the natural pearl market. A number of molluscs also have common names that include the word oyster, usually because they either taste like or look somewhat like true oysters. Examples include, Thorny oysters in the genus Spondylus Pilgrim oyster, another term for a scallop, because of its good flavor, it commands high prices. Oysters are filter feeders, drawing water in over their gills through the beating of cilia. Suspended plankton and particles are trapped in the mucus of a gill, and from there are transported to the mouth, where they are eaten, digested, Oysters feed most actively at temperatures above 10 °C
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Minnesota Department of Natural Resources
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The Minnesota Department of Natural Resources is the agency of the U. S. state of Minnesota charged with conserving and managing the states natural resources. The agency maintains areas such as parks, state forests, recreational trails, and recreation areas as well as managing minerals, wildlife. The agency is divided into six divisions - Ecological & Water Resources, Enforcement, Fish & Wildlife, Forestry, Lands & Minerals. Efforts to conserve Minnesotas wildlife began as early as 1876, with an association established to protect the states timber resources. However, those efforts became futile as the took over. Over time, there were attempts to control the destruction of resources. In 1911 the Minnesota Forest Service was established to conserve the forests by promoting fire prevention and protection. The first agency created to maintain Minnesotas resources was founded in 1931 by the Minnesota Legislature as the Department of Conservation, the Great Depression was an important time for the Department of Conservation. Federal unemployment programs such as the Civilian Conservation Corps and the Works Progress Administration provided labor to construct buildings, clear trails, many of the buildings in Minnesotas state parks were built during this period. In 1971 the name of the agency was changed to the Department of Natural Resources to better reflect its broader responsibilities, more sections of the Minnesota Government were added to the Department and many of the division names changed. Old policies were replaced with new and more prevalent ones geared towards issues associated with an increase in land use. The Division of Ecological and Water Resources studies the ecosystems within Minnesota, the division is involved in locating and protecting endangered and threatened species, as well as the habitats that are vital to the conservation of those species. Another part of the divisions responsibilities is in managing threats against the ecosystem and these threats include, harmful invasive species, fish and wildlife diseases, and the negative impact human development can have on the environment. One of the largest programs that the Division of Ecological Resources is in charge of is Minnesota’s Nongame Wildlife Program and this would include trumpeter swans, bald eagles and Minnesota’s state bird, the common loon. The division is also accountable for all lakes, rivers and streams, wetlands, the division enforces permits implemented to protect and preserve Minnesotas water resources. As the name implies, the focuses on the enforcement of Minnesota’s natural resource laws. Originally part of the Fish and Game Division, the Enforcement Division’s goal has not changed much, Conservation Officers employed by this division enforce laws regarding hunting, fishing, trapping, recreational vehicles, State Parks and wild rice harvesting. A second focus is educating the public about safety, classes are taught by trained volunteers and are often related to the enforced laws
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Foot (unit)
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The foot is a unit of length in the imperial and US customary systems of measurement. Since 1959, both units have been defined by international agreement as equivalent to 0.3048 meters exactly, in both systems, the foot comprises 12 inches and three feet compose a yard. Historically the foot was a part of local systems of units, including the Greek, Roman, Chinese, French. It varied in length from country to country, from city to city and its length was usually between 250 mm and 335 mm and was generally, but not always, subdivided into 12 inches or 16 digits. The United States is the industrialized nation that uses the international foot and the survey foot in preference to the meter in its commercial, engineering. The foot is legally recognized in the United Kingdom, road signs must use imperial units, the measurement of altitude in international aviation is one of the few areas where the foot is widely used outside the English-speaking world. The length of the international foot corresponds to a foot with shoe size of 13,14,15.5 or 46. Historically the human body has been used to provide the basis for units of length. The foot of a male is typically about 15. 3% of his height, giving a person of 160 cm a foot of 245 mm. These figures are less than the used in most cities over time. Archeologists believe that the Egyptians, Ancient Indians and Mesopotamians preferred the cubit while the Romans, under the Harappan linear measures, Indus cities during the Bronze Age used a foot of 13.2 inches and a cubit of 20.8 inches. The Egyptian equivalent of the measure of four palms or 16 digits—was known as the djeser and has been reconstructed as about 30 cm. The Greek foot had a length of 1⁄600 of a stadion, one stadion being about 181.2 m, the standard Roman foot was normally about 295.7 mm, but in the provinces, the pes Drusianus was used, with a length of about 334 mm. Originally both the Greeks and the Romans subdivided the foot into 16 digits, but in later years, after the fall of the Roman Empire, some Roman traditions were continued but others fell into disuse. In AD790 Charlemagne attempted to reform the units of measure in his domains and his units of length were based on the toise and in particular the toise de lÉcritoire, the distance between the fingertips of the outstretched arms of a man. The toise has 6 pieds each of 326.6 mm, at the same time, monastic buildings used the Carolingian foot of 340 mm. The procedure for verification of the foot as described in the 16th century by Jacob Koebel in his book Geometrei, the measures of Iron Age Britain are uncertain and proposed reconstructions such as the Megalithic Yard are controversial. Later Welsh legend credited Dyfnwal Moelmud with the establishment of their units, the Belgic or North German foot of 335 mm was introduced to England either by the Belgic Celts during their invasions prior to the Romans or by the Anglo-Saxons in the 5th & 6th century
