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.
Mattole River
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The Mattole River is a river on the north coast of California, that flows northerly, then westerly into the Pacific Ocean. A short section of the flows through northern Mendocino County. Communities, from north to south, closely associated with the Mattole River include, Petrolia, Honeydew, Ettersburg, Thorn Junction, the river enters the ocean at the Mattole Estuary about 4 miles west-southwest of Petrolia and 10 miles south of Cape Mendocino. Mattole refers to an Athabaskan Indian people, the Mattole and they historically called themselves Mattóal or bedool, but were called by neighboring Wyott Indians Medol or metuul. The Mattole lived principally on the Mattole and Bear rivers and this war-like tribe was practically exterminated because of its resistance to white settlers during the Bald Hills War. The local tradition is that Mattole means clear water, the river and its 74 tributaries drain about 304 square miles, including the eastern side of the King Range, and flows through Mattole Valley before emptying into the Pacific Ocean. Although the Mattole Rivers source is at about 1,780 feet elevation, the North Fork of the Mattole River enters the river main stem just west of Petrolia. For most of its length, the river is only a 4.2 miles east of the King Range National Conservation Area, about halfway to the ocean, near Honeydew, California, the river passes by Humboldt Redwoods State Park. There are numerous tributaries and creeks that feed the drainage area, some of the largest are the Upper North Fork at Honeydew, Honeydew, Bear, Rattlesnake, and Oil Creeks. The Mattole River has been declared a 303 impaired waterbody that flows into a Marine Protected Area, the river is used for recreation and agricultural, municipal and industrial water supply. It also provides wildlife habitat including cold freshwater habitat for fish migration, the Mattole River is home to three salmonid species listed as threatened under the Federal Endangered Species Act, chinook and coho salmon, and steelhead. Coho salmon are listed as threatened under the California State Endangered Species Act. In 2010-2011 ten coho were counted and five redds, but these numbers are still 95% lower than 2006-2007, each salmon run is on a three-year cycle. Recently the group planned a project to decrease winter runoff. This suggests that re-establishment of beaver populations would be 80 times more effective in recovery efforts than large woody debris placement alone. Riparian zones of the Mattole also support Bigleaf maple, Red alder, Fremont cottonwood, Oregon ash, arthur W. Way County Memorial Park is on the north bank of and adjacent to the river. List of rivers in California Mattole Restoration Council Mattole Salmon Group Sanctuary Forest
3.
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
4.
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
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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Brackish water
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Brackish water or briny water is water that has more salinity than fresh water, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, the word comes from the Middle Dutch root brak. Brackish water is also the primary product of the salinity gradient power process. Because brackish water is hostile to the growth of most terrestrial plant species, without appropriate management it is damaging to the environment. Technically, brackish water contains between 0.5 and 30 grams of salt per litre—more often expressed as 0.5 to 30 parts per thousand, thus, brackish covers a range of salinity regimes and is not considered a precisely defined condition. It is characteristic of many brackish surface waters that their salinity can vary considerably over space and/or time, brackish water condition commonly occurs when fresh water meets seawater. In fact, the most extensive brackish water habitats worldwide are estuaries, the River Thames flowing through London is a classic river estuary. A similar pattern of replacement can be observed with the aquatic plants and this type of ecological succession from a freshwater to marine ecosystem is typical of river estuaries. Salmon are anadromous, meaning live in the sea but ascend rivers to spawn, eels are catadromous, living in rivers and streams. Besides the species migrate through estuaries, there are many other fish that use them as nursery grounds for spawning or as places young fish can feed. Herring and plaice are two commercially important species that use the Thames Estuary for this purpose, estuaries are also commonly used as fishing grounds, and as places for fish farming or ranching. Another important brackish water habitat is the swamp or mangal. Many, though not all, mangrove swamps fringe estuaries and lagoons where the salinity changes with each tide, like estuaries, mangrove swamps are extremely important breeding grounds for many fish, with species such as snappers, halfbeaks, and tarpon spawning or maturing among them. Mangroves represent important nesting site for numerous birds groups such as herons, storks, spoonbills, ibises, kingfishers, the Sundarbans and Bhitarkanika Mangroves are two of the large mangrove forests in the world, both on the coast of the Bay of Bengal. Some seas and lakes are brackish, the Baltic Sea is a brackish sea adjoining the North Sea. Because the salt water coming in from the sea is denser than freshwater, limited mixing occurs because of the lack of tides and storms, with the result that the fish fauna at the surface is freshwater in composition while that lower down is more marine. Cod are an example of a species found in deep water in the Baltic. The Caspian Sea is the worlds largest lake and contains brackish water with a salinity about one-third that of normal seawater, the Caspian is famous for its peculiar animal fauna, including one of the few non-marine seals and the great sturgeons, a major source of caviar
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Tide
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Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation of the Earth. Some shorelines experience a semi-diurnal tide—two nearly equal high and low tides each day, other locations experience a diurnal tide—only one high and low tide each day. A mixed tide—two uneven tides a day, or one high, Tides vary on timescales ranging from hours to years due to a number of factors. To make accurate records, tide gauges at fixed stations measure water level over time, gauges ignore variations caused by waves with periods shorter than minutes. These data are compared to the level usually called mean sea level. Tidal phenomena are not limited to the oceans, but can occur in other systems whenever a gravitational field varies in time. For example, the part of the Earth is affected by tides. Tide changes proceed via the following stages, Sea level rises over several hours, covering the intertidal zone, the water rises to its highest level, reaching high tide. Sea level falls over several hours, revealing the intertidal zone, the water stops falling, reaching low tide. Oscillating currents produced by tides are known as tidal streams, the moment that the tidal current ceases is called slack water or slack tide. The tide then reverses direction and is said to be turning, slack water usually occurs near high water and low water. But there are locations where the moments of slack tide differ significantly from those of high, Tides are commonly semi-diurnal, or diurnal. The two high waters on a day are typically not the same height, these are the higher high water. Similarly, the two low waters each day are the low water and the lower low water. The daily inequality is not consistent and is small when the Moon is over the equator. From the highest level to the lowest, Highest Astronomical Tide – The highest tide which can be predicted to occur, note that meteorological conditions may add extra height to the HAT. Mean High Water Springs – The average of the two high tides on the days of spring tides, mean High Water Neaps – The average of the two high tides on the days of neap tides. Mean Sea Level – This is the sea level
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Sediment
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For sediment in beverages, see dregs. For example, sand and silt can be carried in suspension in water and on reaching the sea be deposited by sedimentation. Sediments are most often transported by water, but also wind, beach sands and river channel deposits are examples of fluvial transport and deposition, though sediment also often settles out of slow-moving or standing water in lakes and oceans. Desert sand dunes and loess are examples of transport and deposition. Glacial moraine deposits and till are ice-transported sediments, sediment can be classified based on its grain size and/or its composition. Sediment size is measured on a log base 2 scale, called the Phi scale, composition of sediment can be measured in terms of, parent rock lithology mineral composition chemical make-up. This leads to an ambiguity in which clay can be used as both a size-range and a composition, sediment is transported based on the strength of the flow that carries it and its own size, volume, density, and shape. Stronger flows will increase the lift and drag on the particle, causing it to rise, rivers and streams carry sediment in their flows. This sediment can be in a variety of locations within the flow and these relationships are shown in the following table for the Rouse number, which is a ratio of sediment fall velocity to upwards velocity. If the upwards velocity is less than the settling velocity, but still high enough for the sediment to move, it will move along the bed as bed load by rolling, sliding. If the upwards velocity is higher than the velocity, the sediment will be transported high in the flow as wash load. As there are generally a range of different particle sizes in the flow, sediment motion can create self-organized structures such as ripples, dunes, antidunes on the river or stream bed. These bedforms are often preserved in rocks and can be used to estimate the direction. Overland flow can erode soil particles and transport them downslope, the erosion associated with overland flow may occur through different methods depending on meteorological and flow conditions. If the initial impact of rain droplets dislodges soil, the phenomenon is called rainsplash erosion, if overland flow is directly responsible for sediment entrainment but does not form gullies, it is called sheet erosion. If the flow and the substrate permit channelization, gullies may form, glaciers carry a wide range of sediment sizes, and deposit it in moraines. The overall balance between sediment in transport and sediment being deposited on the bed is given by the Exner equation and this expression states that the rate of increase in bed elevation due to deposition is proportional to the amount of sediment that falls out of the flow. This can be localized, and simply due to obstacles, examples are scour holes behind boulders, where flow accelerates
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Holocene
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The Holocene is the geological epoch that began after the Pleistocene at approximately 11,700 years before present. The term Recent has often used as an exact synonym of Holocene. The Holocene is part of the Quaternary period and its name comes from the Ancient Greek words ὅλος and καινός, meaning entirely recent. It has been identified with the current warm period, known as MIS1, given these, a new term, Anthropocene, is specifically proposed and used informally only for the very latest part of modern history involving significant human impact. It is accepted by the International Commission on Stratigraphy that the Holocene started approximately 11,700 years ago, the epoch follows the Pleistocene and the last glacial period. The Holocene can be subdivided into five time intervals, or chronozones, based on climatic fluctuations, Preboreal, Boreal, Atlantic, Subboreal and they find a general correspondence across Eurasia and North America, though the method was once thought to be of no interest. The scheme was defined for Northern Europe, but the changes were claimed to occur more widely. The periods of the include a few of the final pre-Holocene oscillations of the last glacial period. Paleontologists have not defined any faunal stages for the Holocene, if subdivision is necessary, periods of human technological development, such as the Mesolithic, Neolithic, and Bronze Age, are usually used. However, the time periods referenced by these terms vary with the emergence of those technologies in different parts of the world, climatically, the Holocene may be divided evenly into the Hypsithermal and Neoglacial periods, the boundary coincides with the start of the Bronze Age in Europe. According to some scholars, a division, the Anthropocene, has now begun. Continental motions due to plate tectonics are less than a kilometre over a span of only 10,000 years, however, ice melt caused world sea levels to rise about 35 m in the early part of the Holocene. The sea level rise and temporary land depression allowed temporary marine incursions into areas that are now far from the sea, Holocene marine fossils are known, for example, from Vermont and Michigan. Other than higher-latitude temporary marine incursions associated with depression, Holocene fossils are found primarily in lakebed, floodplain. Holocene marine deposits along low-latitude coastlines are rare because the rise in sea levels during the period exceeds any likely tectonic uplift of non-glacial origin, post-glacial rebound in the Scandinavia region resulted in the formation of the Baltic Sea. The region continues to rise, still causing weak earthquakes across Northern Europe, the equivalent event in North America was the rebound of Hudson Bay, as it shrank from its larger, immediate post-glacial Tyrrell Sea phase, to near its present boundaries. Climate has been stable over the Holocene. It appears that this was influenced by the glacial ice remaining in the Northern Hemisphere until the later date
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Geomorphology
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Geomorphology is the scientific study of the origin and evolution of topographic and bathymetric features created by physical, chemical or biological processes operating at or near the Earths surface. Geomorphologists work within disciplines such as geography, geology, geodesy, engineering geology, archaeology. This broad base of interests contributes to many styles and interests within the field. Earths surface is modified by a combination of processes that sculpt landscapes, and geologic processes that cause tectonic uplift and subsidence. Many of these factors are strongly mediated by climate, the broad-scale topographies of the Earth illustrate this intersection of surface and subsurface action. Mountain belts are uplifted due to geologic processes, denudation of these high uplifted regions produces sediment that is transported and deposited elsewhere within the landscape or off the coast. On progressively smaller scales, similar ideas apply, where individual landforms evolve in response to the balance of additive processes, often, these processes directly affect each other, ice sheets, water, and sediment are all loads that change topography through flexural isostasy. Topography can modify the climate, for example through orographic precipitation. Many geomorphologists are particularly interested in the potential for feedbacks between climate and tectonics, mediated by geomorphic processes, in addition to these broad-scale questions, geomorphologists address issues that are more specific and/or more local. Fluvial geomorphologists focus on rivers, how they transport sediment, migrate across the landscape, cut into bedrock, respond to environmental and tectonic changes, and interact with humans. Soils geomorphologists investigate soil profiles and chemistry to learn about the history of a landscape and understand how climate, biota. Other geomorphologists study how hillslopes form and change, still others investigate the relationships between ecology and geomorphology. Because geomorphology is defined to comprise everything related to the surface of the Earth and its modification, geomorphologists use a wide range of techniques in their work. These may include fieldwork and field data collection, the interpretation of remotely sensed data, geochemical analyses, geomorphologists may rely on geochronology, using dating methods to measure the rate of changes to the surface. Practical applications of geomorphology include hazard assessment, river control and stream restoration, planetary geomorphology studies landforms on other terrestrial planets such as Mars. Indications of effects of wind, fluvial, glacial, mass wasting, meteor impact, tectonics and this effort not only helps better understand the geologic and atmospheric history of those planets but also extends geomorphological study of the Earth. Planetary geomorphologists often use Earth analogues to aid in their study of surfaces of other planets, other than some notable exceptions in antiquity, geomorphology is a relatively young science, growing along with interest in other aspects of the earth sciences in the mid-19th century. This section provides a brief outline of some of the major figures
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Habitat destruction
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Habitat destruction is the process in which natural habitat is rendered unable to support the species present. In this process, the organisms that used the site are displaced or destroyed. Habitat destruction by human activity is mainly for the purpose of harvesting natural resources for production and urbanization. Clearing habitats for agriculture is the cause of habitat destruction. Other important causes of habitat destruction include mining, logging, trawling, habitat destruction is currently ranked as the primary cause of species extinction worldwide. Perhaps the greatest threat to organisms and biodiversity is the process of habitat loss, temple found that 82% of endangered bird species were significantly threatened by habitat loss. Endemic organisms with limited ranges are most affected by destruction, mainly because these organisms are not found anywhere else within the world. Many endemic organisms have very specific requirements for their survival that can only be found within a certain ecosystem, extinction may also take place very long after the destruction of habitat, a phenomenon known as extinction debt. Habitat destruction can also decrease the range of certain organism populations, one of the most famous examples is the impact upon Chinas giant panda, once found across the nation. Now it is found in fragmented and isolated regions in the southwest of the country. Biodiversity hotspots are chiefly tropical regions that feature high concentrations of species and. These hotspots are suffering from loss and destruction. Most of the habitat on islands and in areas of high human population density has already been destroyed. Islands suffering extreme habitat destruction include New Zealand, Madagascar, the Philippines, South and East Asia — especially China, India, Malaysia, Indonesia, and Japan — and many areas in West Africa have extremely dense human populations that allow little room for natural habitat. Marine areas close to highly populated coastal cities also face degradation of their coral reefs or other marine habitat and these areas include the eastern coasts of Asia and Africa, northern coasts of South America, and the Caribbean Sea and its associated islands. Regions of unsustainable agriculture or unstable governments, which may go hand-in-hand, central America, Sub-Saharan Africa, and the Amazonian tropical rainforest areas of South America are the main regions with unsustainable agricultural practices and/or government mismanagement. Areas of high agricultural output tend to have the highest extent of habitat destruction, in the U. S. less than 25% of native vegetation remains in many parts of the East and Midwest. Only 15% of land area remains unmodified by human activities in all of Europe, tropical rainforests have received most of the attention concerning the destruction of habitat
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Soil erosion
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Soil erosion is the displacement of upper layer of soil. The erosion of soil is a naturally occurring process on all land, the agents of soil erosion are water and wind, each contributing a significant amount of soil loss each year. Soil erosion may be a process that continues relatively unnoticed. The loss of soil from farmland may be reflected in reduced crop production potential, lower water quality. While erosion is a process, human activities have increased by 10–40 times the rate at which erosion is occurring globally. 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 centimeters 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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Deforestation
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Deforestation, clearance or clearing is the removal of a forest or stand of trees where the land is thereafter converted to a non-forest use. Examples of deforestation include conversion of forestland to farms, ranches, the most concentrated deforestation occurs in tropical rainforests. About 30% of Earths land surface is covered by forests, Deforestation occurs for multiple reasons, trees are cut down to be used for building or sold as fuel, while cleared land is used as pasture for livestock and plantation. The removal of trees without sufficient reforestation has resulted in damage to habitat, biodiversity loss and it has adverse impacts on biosequestration of atmospheric carbon dioxide. Deforestation has also used in war to deprive the enemy of cover for its forces. Modern examples of this were the use of Agent Orange by the British military in Malaya during the Malayan Emergency, as of 2005, net deforestation rates have ceased to increase in countries with a per capita GDP of at least US$4,600. Deforested regions typically incur significant adverse soil erosion and frequently degrade into wasteland, disregard of ascribed value, lax forest management and deficient environmental laws are some of the factors that allow deforestation to occur on a large scale. In many countries, deforestation, both naturally occurring and human-induced, is an ongoing issue, Deforestation causes extinction, changes to climatic conditions, desertification, and displacement of populations as observed by current conditions and in the past through the fossil record. More than half of all plant and land animal species in the live in tropical forests. Between 2000 and 2012,2.3 million square kilometres of forests around the world were cut down, as a result of deforestation, only 6.2 million square kilometres remain of the original 16 million square kilometres of forest that formerly covered the Earth. According to the United Nations Framework Convention on Climate Change secretariat, subsistence farming is responsible for 48% of deforestation, commercial agriculture is responsible for 32%, logging is responsible for 14%, and fuel wood removals make up 5%. Experts do not agree on whether industrial logging is an important contributor to global deforestation, some argue that poor people are more likely to clear forest because they have no alternatives, others that the poor lack the ability to pay for the materials and labour needed to clear forest. One study found that population increases due to fertility rates were a primary driver of tropical deforestation in only 8% of cases. Other causes of contemporary deforestation may include corruption of government institutions, the distribution of wealth and power, population growth and overpopulation. Globalization is often viewed as another cause of deforestation, though there are cases in which the impacts of globalization have promoted localized forest recovery. The degradation of forest ecosystems has also traced to economic incentives that make forest conversion appear more profitable than forest conservation. Some commentators have noted a shift in the drivers of deforestation over the past 30 years, Deforestation is ongoing and is shaping climate and geography. Deforestation is a contributor to global warming, and is cited as one of the major causes of the enhanced greenhouse effect
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Overgrazing
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Overgrazing occurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods. It can be caused by either livestock in poorly managed agricultural applications, game reserves and it can also be caused by immobile, travel restricted populations of native or non-native wild animals. The only thing to stop overgrazing is to limit the space to roam around. Cows are the things that causes overgrazing and overgrazing can lead to desertification. It reduces the usefulness, productivity, and biodiversity of the land and is one cause of desertification and erosion, Overgrazing is also seen as a cause of the spread of invasive species of non-native plants and of weeds. Sustainable grassland production is based on grass and grassland management, land management, animal management, grazing management, with sustainable agriculture and agroecology practices, is the foundation of grassland-based livestock production since it affects both animal and plant health and productivity. In some regions of the United States under continuous grazing, overgrazed pastures are predominated by short-grass species such as bluegrass, in all cases, palatable tall grasses such as orchard grass are sparse or non-existent. Under rotational grazing, overgrazed plants do not have time to recover to the proper height between grazing events. The animals resume grazing before the plants have restored carbohydrate reserves, another indicator of overgrazing in some parts of North America is that livestock run out of pasture, and hay needs to be fed early in the fall. In contrast, most areas of the world do not experience the climatic regime as the continental United States. Overgrazing is also indicated in livestock performance and condition, cows having inadequate pasture immediately following their calfs weaning may have poor body condition the following season. This may reduce the health and vigor of cows and calves at calving, also, cows in poor body condition do not cycle as soon after calving, which can result in delayed breeding. This can result in a long calving season, with good cow genetics, nutrition, ideal seasons and controlled breeding 55% to 75% of the calves should come in the first 21 days of the calving season. Poor weaning weights of calves can be caused by insufficient pasture, when cows give less milk, reduction in soil depth, soil organic matter and soil fertility impair the lands future natural and agricultural productivity. Soil fertility can sometimes be mitigated by applying the appropriate lime, however, the loss of soil depth and organic matter takes centuries to correct. Their loss is critical in determining the soils water-holding capacity and how well pasture plants do during dry weather, native plant grass species, both individual bunch grasses and in grasslands, are especially vulnerable. In the continental United States, to prevent overgrazing, match the forage supplement to the herds requirement and this means that a buffer needs to be in the system to adjust for the fastest growth of forages. Another potential buffer is to plant warm-season perennial grasses such as switchgrass and this reduces the area that the livestock can use early in the season, making it easier for them to keep up with the cool-season grasses
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Land degradation
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Land degradation is a process in which the value of the biophysical environment is affected by a combination of human-induced processes acting upon the land. It is viewed as any change or disturbance to the land perceived to be deleterious or undesirable, Natural hazards are excluded as a cause, however human activities can indirectly affect phenomena such as floods and bush fires. This is considered to be an important topic of the 21st century due to the land degradation has upon agronomic productivity, the environment. It is estimated that up to 40% of the agricultural land is seriously degraded. Land degradation is a term that can be applied differently across a wide range of scenarios. There are four ways of looking at land degradation and its impact on the environment around it. This can be seen through a loss of biomass, a loss of productivity or in potential productivity, or a loss or change in vegetative cover. Action in the capacity to provide resources for human livelihoods. This can be measured from a line of past land use. Loss of biodiversity, A loss of range of species or ecosystem complexity as a decline in the environmental quality, shifting ecological risk, increased vulnerability of the environment or people to destruction or crisis. This is measured through a line in the form of pre-existing risk of crisis or destruction. A problem with defining land degradation is that one group of people might view as degradation. Overall,36 types of land degradation can be assessed, all are induced or aggravated by human activities, e. g. sheet erosion, silting, aridification, salinization, urbanization, etc. Land degradation is a global problem largely related to agricultural use. g and this is frequent in semi-arid environments, where fuelwood shortages are often severe. It is a significant factor in Afghanistan, the growing population pressure, during 1980-1990, has led to decreases in the already small areas of agricultural land per person in six out of eight countries. Population pressure also operates through other mechanisms, high population density is not always related to land degradation. Rather, it is the practices of the population that can cause a landscape to become degraded. Populations can be a benefit to the land and make it more productive than it is in its natural state, Land degradation is an important factor of internal displacement in many African and Asian countries
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Overfishing
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Overfishing is a form of overexploitation where fish stocks are reduced to below acceptable levels. Overfishing can occur in bodies of any sizes, such as ponds, rivers, lakes or oceans. Sustained overfishing can lead to critical depensation, where the population is no longer able to sustain itself. Some forms of overfishing, for example the overfishing of sharks, has led to the upset of entire marine ecosystems, the ability of a fishery to recover from overfishing depends on whether the ecosystems conditions are suitable for the recovery. For example, once trout have been overfished, carp might take over in a way makes it impossible for the trout to re-establish a breeding population. Overfishing occurs when fish are caught than the population can replace through natural reproduction. Gathering as many fish as possible may seem like a profitable practice, the results not only affect the balance of life in the oceans, but also the social and economic well-being of the coastal communities who depend on fish for their way of life. Overfishing has significantly affected many fisheries around the world, as much as 85% of the worlds fisheries may be over-exploited, depleted, fully exploited or in recovery from exploitation. Significant overfishing has been observed in pre-industrial times, in particular, the overfishing of the western Atlantic Ocean from the earliest days of European colonisation of the Americas has been well documented. Following World War Two, industrial fishing rapidly expanded with rapid increases in worldwide fishing catches, however, many fisheries have either collapsed or degraded to a point where increased catches are no longer possible. Daniel Pauly, a fisheries scientist known for pioneering work on the impacts on global fisheries, has commented. We are gradually winning this war to exterminate them, and to see this destruction happen, for nothing really – for no reason – that is a bit frustrating. Examples of overfishing exist in such as the North Sea, the Grand Banks of Newfoundland. In these locations, overfishing has not only proved disastrous to fish stocks, the Peruvian coastal anchovy fisheries crashed in the 1970s after overfishing and an El Niño season largely depleted anchovies from its waters. Anchovies were a natural resource in Peru, indeed,1971 alone yielded 10.2 million metric tons of anchovies. However, the five years saw the Peruvian fleets catch amount to only about 4 million tons. This was a loss to Perus economy. The collapse of the cod fishery off Newfoundland, and the 1992 decision by Canada to impose a moratorium on the Grand Banks, is a dramatic example of the consequences of overfishing
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Eutrophication
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Eutrophication, or more precisely hypertrophication, is the enrichment of a water body with nutrients, usually with an excess amount of nutrients. This process induces growth of plants and algae and due to the biomass load, one example is the bloom or great increase of phytoplankton in a water body as a response to increased levels of nutrients. Eutrophication is almost always induced by the discharge of phosphate-containing detergents, fertilizers, or sewage, Eutrophication arises from the oversupply of nutrients, which leads to overgrowth of plants and algae. After such organisms die, the degradation of their biomass consumes the oxygen in the water. According to Ullmanns Encyclopedia, the limiting factor for eutrophication is phosphate. Phosphorus is a nutrient for plants to live, and is the limiting factor for plant growth in many freshwater ecosystems. Phosphate adheres tightly to soil, so it is transported by erosion. Once translocated to lakes, the extraction of phosphate into water is slow, the sources of these excess phosphates are phosphates in detergent, industrial/domestic run-offs, and fertilizers. With the phasing out of phosphate-containing detergents in the 1970s, industrial/domestic run-off, cultural Eutrophication is the process that speeds up natural eutrophication because of human activity. Extra nutrients are supplied by treatment plants, golf courses, fertilizers, farms. When algae die, they decompose and the contained in that organic matter are converted into inorganic form by microorganisms. This decomposition process consumes oxygen, which reduces the concentration of dissolved oxygen, the depleted oxygen levels in turn may lead to fish kills and a range of other effects reducing biodiversity. Nutrients may become concentrated in a zone and may only be made available again during autumn turn-over or in conditions of turbulent flow. The water becomes cloudy, typically coloured a shade of green, yellow, brown, Eutrophication also decreases the value of rivers, lakes and aesthetic enjoyment. Health problems can occur where eutrophic conditions interfere with drinking water treatment, human activities can accelerate the rate at which nutrients enter ecosystems. Elevated levels of compounds of nitrogen can increase nitrogen availability. Phosphorus is often regarded as the culprit in cases of eutrophication in lakes subjected to point source pollution from sewage pipes. The concentration of algae and the state of lakes correspond well to phosphorus levels in water
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Heavy metals
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Heavy metals are generally defined as metals with relatively high densities, atomic weights, or atomic numbers. The criteria used, and whether metalloids are included, vary depending on the author, more specific definitions have been published, but none of these have been widely accepted. The definitions surveyed in this article encompass up to 96 out of the 118 chemical elements, only mercury, lead, despite this lack of agreement, the term is widely used in science. A density of more than 5 g/cm3 is sometimes quoted as a commonly used criterion and is used in the body of this article. The earliest known metals—common metals such as iron, copper, and tin, and precious metals such as silver, gold, and platinum—are heavy metals. From 1809 onwards, light metals, such as magnesium, aluminium, and titanium, were discovered, as well as less well-known heavy metals including gallium, thallium, and hafnium. Some heavy metals are essential nutrients, or relatively harmless. Other heavy metals, such as cadmium, mercury, and lead, are highly poisonous, potential sources of heavy metal poisoning include mining and industrial wastes, agricultural runoff, occupational exposure, and paints and treated timber. Physical and chemical characterisations of heavy metals need to be treated with caution, as well as being relatively dense, heavy metals tend to be less reactive than lighter metals and have much less soluble sulfides and hydroxides. Heavy metals are scarce in the Earths crust but are present in many aspects of modern life. They are used in, for example, golf clubs, cars, antiseptics, self-cleaning ovens, plastics, solar panels, mobile phones, there is no widely agreed criterion-based definition of a heavy metal. Different meanings may be attached to the term, depending on the context, density criteria range from above 3.5 g/cm3 to above 7 g/cm3. Atomic weight definitions can range from greater than sodium, greater than 40, or more than 200, atomic numbers of heavy metals are generally given as greater than 20, sometimes this is capped at 92. Definitions based on atomic number have been criticised for including metals with low densities. For example, rubidium in group 1 of the table has an atomic number of 37 but a density of only 1.532 g/cm3. The same problem may occur with atomic weight based definitions, criteria based on chemical behaviour or periodic table position have been used or suggested. The United States Pharmacopeia includes a test for metals that involves precipitating metallic impurities as their coloured sulfides. The lanthanides satisfy Hawkes three-part description, the status of the actinides is not completely settled, in biochemistry, heavy metals are sometimes defined—on the basis of the Lewis acid behaviour of their ions in aqueous solution—as class B and borderline metals
31.
Polychlorinated biphenyl
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A polychlorinated biphenyl is an organic chlorine compound with the formula C12H10−xClx. Polychlorinated biphenyls were once widely deployed as dielectric and coolant fluids in electrical apparatus, carbonless copy paper, because of their longevity, PCBs are still widely in use, even though their manufacture has declined drastically since the 1960s, when a host of problems were identified. The International Research Agency on Cancer, rendered PCBs as definite carcinogens in humans, according to the U. S. Environmental Protection Agency, PCBs cause cancer in animals and are probable human carcinogens. Many rivers and buildings including schools, parks, and other sites are contaminated with PCBs, some PCBs share a structural similarity and toxic mode of action with dioxin. Other toxic effects such as endocrine disruption and neurotoxicity are known, the bromine analogues of PCBs are polybrominated biphenyls, which have analogous applications and environmental concerns. The compounds are pale-yellow viscous liquids and they are hydrophobic, with low water solubilities —0. 0027-0.42 ng/L for Aroclors, but they have high solubilities in most organic solvents, oils, and fats. They have low vapor pressures at room temperature and they have dielectric constants of 2. 5~2.7, very high thermal conductivity, and high flash points. The density varies from 1.182 to 1.566 kg/L, other physical and chemical properties vary widely across the class. As the degree of chlorination increases, melting point and lipophilicity increase, PCBs do not easily break down or degrade, which made them attractive for industries. PCB mixtures are resistant to acids, bases, oxidation, hydrolysis and they can generate extremely toxic dibenzodioxins and dibenzofurans through partial oxidation. Intentional degradation as a treatment of unwanted PCBs generally requires high heat or catalysis, PCBs readily penetrate skin, PVC, and latex. PCB-resistant materials include Viton, polyethylene, polyvinyl acetate, polytetrafluoroethylene, butyl rubber, nitrile rubber, PCBs are derived from biphenyl, which has the formula C12H10, sometimes written 2. In PCBs, some of the atoms in biphenyl are replaced by chlorine atoms. There are 209 different chemical compounds in which one to ten chlorine atoms can replace hydrogen atoms, PCBs are typically used as mixtures of compounds and are given the single identifying CAS number 1336-36-3. About 130 different individual PCBs are found in commercial PCB products, toxic effects vary depending on the specific PCB. Coplanar or non-ortho The coplanar group members have a rigid structure. They do not activate the AhR, and are not considered part of the dioxin group, because of their lower toxicity, they are of less concern to regulatory bodies. Di-ortho-substituted, non-coplanar PCBs interfere with signal transduction dependent on calcium which may lead to neurotoxicity
32.
Radionuclide
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A radionuclide is an atom that has excess nuclear energy, making it unstable. During those processes, the radionuclide is said to undergo radioactive decay, the unstable nucleus is more stable following the emission, but will sometimes undergo further decay. Radioactive decay is a process at the level of single atoms. However, for a collection of atoms of an element the decay rate. The range of the half-lives of radioactive atoms have no known limits, Radionuclides occur naturally and are artificially produced in nuclear reactors, cyclotrons, particle accelerators or radionuclide generators. There are about 730 radionuclides with half-lives longer than 60 minutes, with the longest half lives are the 32 primordial radionuclides that have survived from the creation of the Solar System. Over 60 further radionuclides are detectable in nature, either as daughters of these, more than 2400 radionuclides have half-lives less than 60 minutes. Most of those are produced artificially, and have very short half-lives. For comparison, there are about 254 stable nuclides, even the lightest element, hydrogen, has a well-known radionuclide, tritium. Elements heavier than lead, and the elements technetium and promethium, unplanned exposure to radionuclides generally has a harmful effect on living organisms including humans, although low levels of exposure occur naturally without harm. However, radionuclides with suitable properties are used in medicine for both diagnosis and treatment. An imaging tracer made with radionuclides is called a radioactive tracer, a pharmaceutical drug made with radionuclides is called a radiopharmaceutical. On Earth, naturally occurring radionuclides fall into three categories, primordial radionuclides, secondary radionuclides, and cosmogenic radionuclides, Radionuclides are produced in stellar nucleosynthesis and supernova explosions along with stable nuclides. Most decay quickly but can still be observed astronomically and can play a part in understanding astronomic processes, primordial radionuclides, such as uranium and thorium, exist in the present time because their half-lives are so long they have not yet completely decayed. It is possible decay may be observed in other nuclides adding to this list of primordial radionuclides, secondary radionuclides are radiogenic isotopes derived from the decay of primordial radionuclides. They have shorter half-lives than primordial radionuclides and they arise in the decay chain of the primordial isotopes thorium-232, uranium-238 and uranium-235. Examples include the natural isotopes of polonium and radium, cosmogenic isotopes, such as carbon-14, are present because they are continually being formed in the atmosphere due to cosmic rays. Many of these radionuclides exist only in trace amounts in nature, secondary radionuclides will occur in proportion to their half-lives, so short-lived ones will be very rare
33.
Hydrocarbon
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In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon, and thus are group 14 hydrides. Hydrocarbons from which one atom has been removed are functional groups. Aromatic hydrocarbons, alkanes, alkenes, cycloalkanes and alkyne-based compounds are different types of hydrocarbons, the classifications for hydrocarbons, defined by IUPAC nomenclature of organic chemistry are as follows, Saturated hydrocarbons are the simplest of the hydrocarbon species. They are composed entirely of single bonds and are saturated with hydrogen, the formula for acyclic saturated hydrocarbons is CnH2n+2. The most general form of saturated hydrocarbons is CnH2n+2, where r is the number of rings and those with exactly one ring are the cycloalkanes. Saturated hydrocarbons are the basis of petroleum fuels and are found as linear or branched species. Substitution reaction is their characteristics property, hydrocarbons with the same molecular formula but different structural formulae are called structural isomers. As given in the example of 3-methylhexane and its higher homologues, chiral saturated hydrocarbons constitute the side chains of biomolecules such as chlorophyll and tocopherol. Unsaturated hydrocarbons have one or more double or triple bonds between carbon atoms and those with double bond are called alkenes. Those with one double bond have the formula CnH2n and those containing triple bonds are called alkyne. Those with one triple bond have the formula CnH2n−2, aromatic hydrocarbons, also known as arenes, are hydrocarbons that have at least one aromatic ring. Hydrocarbons can be gases, liquids, waxes or low melting solids or polymers, in terms of shells, carbon consists of an incomplete outer shell, which comprises 4 electrons, and thus has 4 electrons available for covalent or dative bonding. Some hydrocarbons also are abundant in the solar system, lakes of liquid methane and ethane have been found on Titan, Saturns largest moon, confirmed by the Cassini-Huygens Mission. Hydrocarbons are also abundant in nebulae forming polycyclic aromatic hydrocarbon compounds, hydrocarbons are a primary energy source for current civilizations. The predominant use of hydrocarbons is as a fuel source. In their solid form, hydrocarbons take the form of asphalt, mixtures of volatile hydrocarbons are now used in preference to the chlorofluorocarbons as a propellant for aerosol sprays, due to chlorofluorocarbons impact on the ozone layer. Methane and ethane are gaseous at ambient temperatures and cannot be liquefied by pressure alone. Propane is however easily liquefied, and exists in propane bottles mostly as a liquid, butane is so easily liquefied that it provides a safe, volatile fuel for small pocket lighters
34.
River Exe
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It flows for 60 miles and reaches the sea at a substantial ria, the Exe Estuary, on the south coast of Devon. Historically, its lowest bridging point was at Exeter, though there is now a viaduct for the M5 motorway about 3 kilometres south of the city centre. The rivers name is an anglicisation of the Latin isca, itself a form of a Brittonic root meaning water or, more exactly. It seems to be a cognate of pysg, the Welsh word for fish. The river gave the name of Exeter and many settlements along its course, including Exford, Up Exe, Nether Exe, Exwick, Exton, Exminster, and Exebridge. The seaside town of Exmouth is at the east side of the estuary mouth, the river fuelled Exeters growth and relative importance in medieval times, and the citys first industrial area was developed at Exe Island, created by a series of leats to the west of the city. The island was home to numerous watermills producing paper and textiles, tides on the river are limited at Countess Wear, the site of a weir commissioned by the Countess of Devon in the 13th century. The Exeter Canal bypasses this weir to enable ships to reach Exeter Quay, at high tide, the estuary forms a large body of water that is heavily used for water sports especially sailing, windsurfing and water skiing. Railways run along both sides of the estuary, the Avocet Line from Exeter to Exmouth on the eastern side, and the South Devon main line on the western. The latter is on a causeway, the South Devon Railway sea wall from Powderham to Dawlish Warren, at low tide, extensive mud flats are exposed, and these are an important feeding source for wading birds. Along with other rias in South West England, the Exe estuary is an important site for wintering waders, Dawlish Warren is a favoured site for birdwatching. The river has a low pH but does not suffer from an acid rain problem. It is populated with wild brown trout, and in the lower reaches coarse fish including dace, chub, perch, roach, pike and bream and some grayling, there is a run of Atlantic salmon and a sparse run of sea trout. Just 150 metres below the union of the River Barle is Black Pool, which is one of the best, the smaller fish species present include stone loach and there are good reasons to assume others are present. In 2008 the Environment Agency embarked on a project to clean the river from vegetation forming, in order to do so the water level decreased to its lowest level – less water remained than the droughts the city has suffered. Rivers of the United Kingdom Lawrence, Rod, the Exe, A River for Wildlife. RSPB reserves, Exminster & Powderham Marshes Dawlish Warren Nature Reserve
35.
Darwin, Northern Territory
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Darwin /ˈdɑːrwᵻn/ is the capital city of the Northern Territory of Australia. Situated on the Timor Sea, Darwin is the largest city in the sparsely populated Northern Territory and it is the smallest and most northerly of the Australian capital cities, and acts as the Top Ends regional centre. Darwins proximity to South East Asia makes it a link between Australia and countries such as Indonesia and East Timor, the Stuart Highway begins in Darwin, ending at Port Augusta in South Australia. The city itself is built on a low bluff overlooking the harbour and its suburbs spread out over some area, beginning at Lee Point in the north and stretching to Berrimah in the east. Past Berrimah, the Stuart Highway goes on to Darwins satellite city, Palmerston, the Darwin region, like the rest of the Top End, has a tropical climate, with a wet and a dry season. Prone to cyclone activity during the wet season, Darwin experiences heavy monsoonal downpours, during the dry season, the city is met with blue skies and gentle sea breezes from the harbour. The greater Darwin area is the home of the Larrakia people. On 9 September 1839, HMS Beagle sailed into Darwin harbour during its surveying of the area, John Clements Wickham named the region Port Darwin in honour of their former shipmate Charles Darwin, who had sailed with them on the ships previous voyage which had ended in October 1836. The settlement there became the town of Palmerston in 1869, and was renamed Darwin in 1911. The city has been almost entirely rebuilt four times, following devastation caused by the 1897 cyclone, the 1937 cyclone, Japanese air raids during World War II, the Aboriginal people of the Larrakia language group are the traditional custodians and the first inhabitants of the greater Darwin area. They had trading routes with Southeast Asia, and imported goods from as far afield as South, established songlines penetrated throughout the country, allowing stories and histories to be told and retold along the routes. The extent of shared songlines and history of multiple groups within this area is still contestable. The Dutch visited Australias northern coastline in the 1600s and landed on the Tiwi Islands only to be repelled by the Tiwi peoples, the Dutch created the first European maps of the area. This accounts for the Dutch names in the area, such as Arnhem Land, the first British person to see Darwin harbour appears to have been Lieutenant John Lort Stokes of HMS Beagle on 9 September 1839. The ships captain, Commander John Clements Wickham, named the port after Charles Darwin, in 1863, the Northern Territory was tranferred from New South Wales to South Australia. In 1864 South Australia sent B. T. Finniss north as Government Resident to survey, Finniss chose a site at Escape Cliffs, near the entrance to Adelaide River, about 60 km northeast of the modern city. This attempt was short-lived, however, and the settlement abandoned by 1865, on 5 February 1869, George Goyder, the Surveyor-General of South Australia, established a small settlement of 135 people at Port Darwin between Fort Hill and the escarpment. Goyder named the settlement Palmerston, after the British Prime Minister Lord Palmerston, in 1870, the first poles for the Overland Telegraph were erected in Darwin, connecting Australia to the rest of the world
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Northern Territory
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The Northern Territory is a federal Australian territory in the central and central northern regions of Australia. It shares borders with Western Australia to the west, South Australia to the south, to the north, the territory is bordered by the Timor Sea, the Arafura Sea and the Gulf of Carpentaria. Despite its large area—over 1,349,129 square kilometres, the Northern Territorys population of 244,000 makes it the least populous of Australias eight major states and territories, having fewer than half as many people as Tasmania. The archaeological history of the Northern Territory begins over 40,000 years ago when Indigenous Australians settled the region, makassan traders began trading with the indigenous people of the Northern Territory for trepang from at least the 18th century onwards. The coast of the territory was first seen by Europeans in the 17th century, the British were the first Europeans to attempt to settle the coastal regions. After three failed attempts to establish a settlement, success was achieved in 1869 with the establishment of a settlement at Port Darwin. Today the economy is based on tourism, especially Kakadu National Park in the Top End and the Uluru-Kata Tjuta National Park in central Australia, the capital and largest city is Darwin. The population is not concentrated in regions but rather along the Stuart Highway. The other major settlements are Palmerston, Alice Springs, Katherine, Nhulunbuy, residents of the Northern Territory are often known simply as Territorians and fully as Northern Territorians, or more informally as Top Enders and Centralians. With the coming of the British, there were four attempts to settle the harsh environment of the northern coast. The Northern Territory was part of colonial New South Wales from 1825 to 1863, except for a time from February to December 1846. It was part of South Australia from 1863 to 1911, under the administration of colonial South Australia, the overland telegraph was constructed between 1870 and 1872. A railway was built between Palmerston and Pine Creek between 1883 and 1889. The economic pattern of raising and mining was established so that by 1911 there were 513,000 cattle. Victoria River Downs was at one time the largest cattle station in the world, gold was found at Grove Hill in 1872 and at Pine Creek, Brocks Creek, Burrundi, and copper was found at Daly River. On 1 January 1911, a decade after federation, the Northern Territory was separated from South Australia, alfred Deakin opined at this time To me the question has been not so much commercial as national, first, second, third and last. Either we must accomplish the peopling of the territory or submit to its transfer to some other nation. In late 1912 there was growing sentiment that the name Northern Territory was unsatisfactory, the names Kingsland, Centralia and Territoria were proposed with Kingsland becoming the preferred choice in 1913
37.
Paravur, Kollam
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Paravur, or South Paravoor, is a town and a municipality in the Kollam district of the Indian state of Kerala. The lakes and sea coast of Paravur attract visitors and foreigners with the attraction the interconnection of Paravur Kayal. Paravur lies 21 kilometres from Kollam by road and can be reached within 15 minutes by train from Kollam Junction, Paravur Municipality consists of Kottapuram, Koonayil, Thekkumbhagam, Chillakkal, Perumpuzha, Nedungolam, Pozhikara, Maniyamkulam, Kurumandal, Kottamoola, Attinpuram & Kochalummoodu. Paravur Municipality is a Grade-II Municipality of Kerala, Paravur is located at 8.78 N76 E. It has an elevation of 10 metres. Paravur,21 kilometers from the Kollam, is a skirt of land stretching in between the backwaters and the sea. The famous Varkala beach is a mere 12 kilometres drive from here, there is an elevation of 6 metres above sea level, extending to 16 metres on the inland. As of 2011 India census, Paravur has a population of 43,739, males constitute 47% of the population and females 53%. Paravur has an literacy rate of 79%, higher than the national average of 59. 5%, male literacy is 81%. In Paravur, 10% of the population are under 6 years of age, total number of households are 9,155. Pozhikara was the headquarters of Paravur. Remnants of the old fort, Thaana and Anchalappees still remain, a mint of the erstwhile Travancore Kingdom for printing and punching their currencies was once situated at Paravur. Paravur panchayat was formed in 1936 as one of the four panchayats sanctioned by Sir C. P. Ramaswamy Iyer, the others were Boothapandi, Nedumangadu, and Perumbavoor. The so formed Paravur panchayat included nine territories-Thekkumbhagam, Kottappuram, Kongal, Pozhikara, Kurumandal, Koonayil, Kalakkode, Bhoothakkulam, sree Ramavarma koyi thampuram from Kilimanoor Palace was the first executive officer of the panchayat. The first election for Paravur panchayat was held in 1942 and Sri Achuthan Pillai became the first elected panchayat president, later Paravur became a Municipality on May 1,1988. For the first seven years it was ruled by special officers, in 1995 after the first Municipal election, Smt. Bhanumati became the first Municipal Chairperson, in April 2016, over 100 people were killed in a fireworks explosion at a local temple in the town. There are so many important roads in Paravur, connecting Kollam city and neighbouring towns like Varkala, Chathannoor, Parippally, Poothakkulam
38.
Kollam
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Kollam or Quilon, formerly Desinganadu, is an old seaport and city on the Laccadive Sea coast of Kerala, India. The city is on the banks Ashtamudi Lake, Kollam has had a strong commercial reputation since the days of the Phoenicians and Romans. Fed by the Chinese trade, it was mentioned by Ibn Battuta in the 14th century as one of the five Indian ports he had seen during the course of his twenty-four year travels, desinganadus rajas exchanged embassies with Chinese rulers while there was a flourishing Chinese settlement at Kollam. In the 9th Century, on his way to Canton, China, Marco Polo, the great Venetian traveller, who was in Chinese service under Kublai Khan in 1275, visited Kollam and other towns on the west coast, in his capacity as a Chinese mandarin. V. Nagam Aiya in his Travancore State Manual records that in 822 AD two East Syrian bishops Mar Sabor and Mar Proth, settled in Quilon with their followers. Two years later the Malabar Era began and Quilon became the city of the Malabar region ahead of Travancore. Kollam is a city on the banks of Ashtamudi Lake that took the title Gods Own Country without much demur. The braids of Ashtamudi Lake lie about 71 kilometres north of the state capital, the city hosts the administrative offices of Kollam district and is a prominent trading city for the state. The proportion of females to males in Kollam city is second highest among the 500 most populous cities in India, Kollam is the least polluted city in India. Four major trading centers/towns around Kollam are Kottarakara, Punalur, Paravur, There was also internal trade through the Punalur Pass connecting the ancient town to Tamil Nadu. The rail links later established to Tamil Nadu supported still stronger trade links, the factories processing marine exports and the processing and packaging of cashewnuts extended its trade across the globe. Kollam is the fourth most populous city in Kerala and the fifth largest in incorporated area and it is known for cashew processing and coir manufacturing. Ashtamudi Lake is considered the gateway to the backwaters of Kerala and is a prominent tourist destination at Kollam. The Kollam urban area includes towns such as Paravur in the south, Kundara in the east. Other important towns in the city suburbs are Eravipuram, Kottiyam, Kannanallur, Kollam appeared as Palombe in Mandevilles Travels, where he claimed it contained a Fountain of Youth. During the later stages of the rule of the Chera monarchy in Kerala, Kollam emerged as the point of trade. Kollam continues to be a business and commercial centre in the Southern Kerala. In 825 CE, the Malayalam calendar, or Kollavarsham, was created in Kollam at meetings held in the city, the present Malayalam calendar is said to have begun with the re-founding of the town, which was rebuilt after its destruction by a fire
39.
Yachats River
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The Yachats River is a short river on the central Oregon coast, about 60 miles west-north-west of Eugene. The name is the name meaning at the foot of the mountain.4 miles later joins with School Fork. Keller Creek and Stump Creek join after about a mile of meandering, the river bed widens significantly and levels out to become very slow moving and turns northward about a half mile, then westward at river mile 8. It meanders westward the rest of the way to the ocean, the sand and stone beach at the river bar is normally very shallow, which allows the tide to change the length of the river as much as a mile. Named tributaries from source to mouth are Grass Creek, School Fork, then Keller, Stump, below that come Axtell, Helms, Werner, Bend, Clear, Carlson, Dawson, Beamer, South Beamer, Marks, Reedy, and Salmon creeks
40.
Yachats, Oregon
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Yachats is a small coastal city in Lincoln County, Oregon, United States. According to Oregon Geographic Names, the name comes from the Siletz language, there is a range of differing etymologies, however. William Bright says the name comes from the Alsea placename yáx̣ayky, at the 2010 census, the citys population was 690. In 2007, Budget Travel magazine named Yachats one of the Ten Coolest Small Towns of the U. S. A. in 2011, Arthur Frommer, founder of Frommers Travel Guides, listed Yachats number seven among his ten favorite vacation destinations in the world. Archeological studies have shown that the Yachats area has been inhabited for at least 1,500 years, remains of a pit-house in Yachats have been radiocarbon dated at approximately 570 AD. Yachats is built on seashell middens and numerous graves left by its past inhabitants, excavations for construction of buildings and U. S. Route 101 uncovered a great many skeletons and artifacts. Most of these part of the fill dirt forming the base of the current highway. For many centuries the Native Americans in this area were hunter-gatherers who migrated between summer camps and winter residences, the Alsea Tribe had as many as 20 permanent villages on the Alsea River and the central Oregon coast. Archeological and linguistic evidence support the existence of a southern Alsea village known as the Yahuch band, by 1860, the Yahuch band was extinct, many having succumbed to European diseases such as smallpox and tuberculosis. The trail climbs 800 feet from downtown Yachats to the summit of Cape Perpetua where it links with the trail system of the Siuslaw National Forest. In Yachats the hunter-gatherer tribes were forced to learn to make a living by agriculture, crops planted near the ocean failed, resulting in many deaths from starvation. Approximately 300 Indians died in just 10 years and they were also allowed to return to hunting. Many of the Indians died during this relocation, homesteaders used the Indian farms and trails to develop the Yachats area. In 1892 the first post office was established in Yachats, until Yachats could be reached by a macadam road, rains made it impossible for the mail to be carried by car. The Roosevelt Memorial Highway, carved out of the rock of Cape Perpetua in 1931, despite the early difficulties of reaching Yachats, the tourist industry began in 1905 with the conversion of a chittum bark warehouse into the first hotel. Today tourism is the main industry. Yachats was part of the war effort in both World Wars I and II, spruce was needed for airplanes during World War I, and in 1918 the U. S. Army Signal Corps undertook logging at Camp 1, an area about 2 miles north of Yachats. A railroad needed for transporting logs to a mill was completed just three days before the war ended, a private company continued the logging operations, however
41.
Amazon River
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The Amazon River, usually abbreviated to Amazon, in South America is the largest river by discharge of water in the world and, according to some authors, the longest in length. Brazilians call this section the Solimões River above its confluence with the Rio Negro to form what Brazilians call the Amazon at the Meeting of Waters at Manaus, the rivers largest city. The Amazon basin is the largest drainage basin in the world, the portion of the rivers drainage basin in Brazil alone is larger than any other rivers basin. The Amazon enters Brazil with only one-fifth of the flow it finally discharges into the Atlantic Ocean, during what many archaeologists call the formative stage, Amazonian societies were deeply involved in the emergence of South Americas highland agrarian systems. Early human settlements were based on low-lying hills or mounds. Shell mounds were the earliest evidences of inhabitation, they represent piles of refuse and are mainly dated between 7500 and 4000 years BP. They are associated with ceramic age cultures, no preceramic shell mounds have been documented so far by archaeologists, artificial earth platforms for entire villages are the second type of mounds. They are best represented by the Marajoara culture, figurative mounds are the most recent types of occupation. There is ample evidence that the surrounding the Amazon River were home to complex and large-scale indigenous societies, mainly chiefdoms who developed large towns. Archeologists estimate that by the time the Spanish conquistador De Orellana travelled across the Amazon in 1541 and these pre-Columbian settlements created highly developed civilizations. For instance, pre-Columbian indigenous people on the island of Marajó may have developed social stratification, in order to achieve this level of development, the indigenous inhabitants of the Amazon rainforest altered the forests ecology by selective cultivation and the use of fire. Scientists argue that by burning areas of the forest repetitiously, the people caused the soil to become richer in nutrients. This created dark soil areas known as terra preta de índio, further research has hypothesized that this practice began around 11,000 years ago. Some say that its effects on forest ecology and regional climate explain the otherwise inexplicable band of rainfall through the Amazon basin. Many indigenous tribes engaged in constant warfare, james Stuart Olson wrote, The Munduruku expansion dislocated and displaced the Kawahíb, breaking the tribe down into much smaller groups. First came to the attention of Europeans in 1770 when they began a series of attacks on Brazilian settlements along the Amazon River. In March 1500, Spanish conquistador Vicente Yáñez Pinzón was the first documented European to sail up the Amazon River. Pinzón called the stream Río Santa María del Mar Dulce, later shortened to Mar Dulce, literally, sweet sea, because of its fresh water pushing out into the ocean
42.
Head of tide
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Head of tide or tidal limit is the farthest point upstream where a river is affected by tidal fluctuations, or where the fluctuations are less than a certain amount. This applies to rivers which flow into tidal bodies such as oceans, bays, though this point may vary due to storms, spring tides, and seasonal or annual differences in water flows, there is generally an average point which is accepted as the head of tide. A rivers tidal data are recorded at various locations downstream of this point, a rivers head of tide may be considered the upper boundary of its estuary. The head of tide is important in surveying, navigation, and fisheries management, as the head of tide is useful for navigation, separate maps can be made of the tidal zones up to the head of tide, such as was done in New Jersey. The head of tide may be many miles upstream from the rivers mouth, for example, on the Hudson River, it is located 140 miles upstream, near Albany, New York. On the Saint Lawrence River, tides affect shipping upstream past Quebec City, which is located several hundred miles inland from the Gulf of Saint Lawrence, tidal bore tidal river The Tideway
43.
Fjord
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Geologically, a fjord or fiord is a long, narrow inlet with steep sides or cliffs, created by glacial erosion. Norways coastline is estimated at 29,000 kilometres with 1,190 fjords, a fjord is formed when a glacier cuts a U-shaped valley by ice segregation and abrasion of the surrounding bedrock. Glacial melting is accompanied by the rebounding of Earths crust as the ice load, in some cases this rebound is faster than sea level rise. Most fjords are deeper than the adjacent sea, Sognefjord, Norway, fjords generally have a sill or shoal at their mouth caused by the previous glaciers reduced erosion rate and terminal moraine. In many cases this causes extreme currents and large saltwater rapids. Saltstraumen in Norway is often described as the worlds strongest tidal current and these characteristics distinguish fjords from rias, which are drowned valleys flooded by the rising sea. Drammensfjorden is cut almost in two by the Svelvik ridge, a moraine that during the ice cover was under sea level. During the winter there is usually little inflow of freshwater. Surface water and deeper water are mixed during winter because of the cooling of the surface. In the deep there is still fresh water from the summer with less density than the saltier water along the coast. Offshore wind, common in the areas during winter, sets up a current on the surface from the inner to the outer parts. This current on the surface in turn pulls dense salt water from the coast across the fjord threshold, during the summer season there is usually a large inflow of river water in the inner areas. This freshwater gets mixed with saltwater creating a layer of water with a slightly higher surface than the ocean which in turn sets up a current from the river mouths towards the ocean. This current is more salty towards the coast and right under the surface current there is a reverse current of saltier water from the coast. In the deeper parts of the fjord the cold water remaining from winter is still, fjords with a shallow threshold this deep water is not replaced every year and low oxygen concentration makes the deep water unsuitable for fish and animals. In the most extreme cases there is a constant barrier of freshwater on the surface, gaupnefjorden branch of Sognefjorden is strongly affected by freshwater as glacial river flow in. Velfjorden has little inflow of freshwater, as late as 2000, some coral reefs were discovered along the bottoms of the Norwegian fjords. These reefs were found in fjords from the north of Norway to the south, the marine life on the reefs is believed to be one of the most important reasons why the Norwegian coastline is such a generous fishing ground
44.
Lagoon
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A lagoon is a shallow body of water separated from a larger body of water by barrier islands or reefs. Lagoons are commonly divided into coastal lagoons and atoll lagoons and they have also been identified as occurring on mixed-sand and gravel coastlines. There is an overlap between bodies of water classified as coastal lagoons and bodies of water classified as estuaries, lagoons are common coastal features around many parts of the world. Lagoons can also be man-made and used for treatment, as is the case for e. g. aerated lagoons. Lagoons are shallow, often elongated bodies of water separated from a body of water by a shallow or exposed shoal, coral reef. Some authorities include fresh water bodies in the definition of lagoon, the distinction between lagoon and estuary also varies between authorities. Richard A. Davis Jr. restricts lagoon to bodies of water with little or no fresh water inflow, and little or no tidal flow, Davis does state that the terms lagoon and estuary are often loosely applied, even in scientific literature. Timothy M. Kusky characterizes lagoons as normally being elongated parallel to the coast, while estuaries are usually drowned river valleys, coastal lagoons are classified as inland bodies of water. Many lagoons do not include lagoon in their common names, in England, The Fleet at Chesil Beach has also been described as a lagoon. In Latin America, the term laguna in Spanish, which translates to. However, sometimes it is used to describe a full-sized lake, such as Laguna Catemaco in Mexico. The brackish water lagoon may be explicitly identified as a coastal lagoon. In Portuguese the same usage is found, lagoa may be a body of sea water. Lagoon is derived from the Italian laguna, which refers to the waters around Venice, Laguna is attested in English by at least 1612, and had been Anglicized to lagune by 1673. In 1697 William Dampier referred to a Lagune or Lake of Salt water on the coast of Mexico, captain James Cook described an island of Oval form with a Lagoon in the middle in 1769. Atoll lagoons form as coral reefs grow upwards while the islands that the reefs surround subside, unlike the lagoons that form shoreward of fringing reefs, atoll lagoons often contain some deep portions. Coastal lagoons form along gently sloping coasts where barrier islands or reefs can develop off-shore, coastal lagoons do not form along steep or rocky coasts, or if the range of tides is more than 4 metres. Due to the slope of the coast, coastal lagoons are shallow
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River mouth
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A river mouth is the part of a river where the river flows into a larger river, a lake, a reservoir or an ocean. The water from a river can enter the body in a variety of different ways. The motion of the river mainly depends on the density of the river compared to the receiving water and any ambient motion in the receiving water. If the river water is denser than the surface of the receiving water, the river water will then either form an underflow or an interflow within the lake. Alongside these advective transports, inflowing water will also diffuse, at the mouth of a river, the change in flow condition can cause the river to drop any sediment it is carrying. This sediment deposition can generate a variety of landforms, such as deltas, sand bars, spits, many places in England take their names from their positions at the mouths of rivers, for example Plymouth, Sidmouth and Great Yarmouth. Confluence River delta Estuary Liman Aber and Inver
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Creek (tidal)
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A tidal creek, tidal channel, or estuary is the portion of a stream that is affected by ebb and flow of ocean tides, in the case that the subject stream discharges to an ocean, sea or strait. Thus this portion of the stream has variable salinity and electrical conductivity over the tidal cycle, due to the temporal variability of water quality parameters within the tidally influenced zone, there are unique biota associated with tidal creeks, which biota are often specialised to such zones. Creeks may often dry to a channel with little or no flow at low tide. In British English and in other countries in the Commonwealth, as well as some parts of the United States. In parts of southwest England and Wales, the pill is used. On the India and Pakistan borders the term applies to the salt water inlets enclosed by mangroves. Creeks are found dispersed all along the Indian coast, in the Florida Keys, a creek is a narrow channel between islands. There are thousands of examples of tidal creeks throughout the world
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Ecosystem
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An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment, interacting as a system. These biotic and abiotic components are regarded as linked together through nutrient cycles, as ecosystems are defined by the network of interactions among organisms, and between organisms and their environment, they can be of any size but usually encompass specific, limited spaces. Energy, water, nitrogen and soil minerals are other essential components of an ecosystem. The energy that flows through ecosystems is obtained primarily from the sun and it generally enters the system through photosynthesis, a process that also captures carbon from the atmosphere. By feeding on plants and on one another, animals play an important role in the movement of matter and they also influence the quantity of plant and microbial biomass present. Ecosystems are controlled both by external and internal factors, other external factors include time and potential biota. Ecosystems are dynamic entities—invariably, they are subject to disturbances and are in the process of recovering from some past disturbance. Ecosystems in similar environments that are located in different parts of the world can have different characteristics simply because they contain different species. The introduction of species can cause substantial shifts in ecosystem function. Internal factors not only control ecosystem processes but are controlled by them and are often subject to feedback loops. Other internal factors include disturbance, succession and the types of species present, although humans exist and operate within ecosystems, their cumulative effects are large enough to influence external factors like climate. Biodiversity affects ecosystem function, as do the processes of disturbance, classifying ecosystems into ecologically homogeneous units is an important step towards effective ecosystem management, but there is no single, agreed-upon way to do this. The term ecosystem was first used in 1935 in a publication by British ecologist Arthur Tansley, Tansley devised the concept to draw attention to the importance of transfers of materials between organisms and their environment. He later refined the term, describing it as The whole system, including not only the organism-complex, but also the whole complex of physical factors forming what we call the environment. Tansley regarded ecosystems not simply as natural units, but as mental isolates, Tansley later defined the spatial extent of ecosystems using the term ecotope. G. Raymond Lindeman took these ideas one step further to suggest that the flow of energy through a lake was the driver of the ecosystem. Most mineral nutrients, on the hand, are recycled within ecosystems. Ecosystems are controlled both by external and internal factors, external factors, also called state factors, control the overall structure of an ecosystem and the way things work within it, but are not themselves influenced by the ecosystem
