1.
Ekman transport
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Ekman transport, part of Ekman motion theory first investigated in 1902 by Vagn Walfrid Ekman, is the term given for the 90° net transport of the surface layer of a fluid by wind forcing. This phenomenon was first noted by Fridtjof Nansen, who recorded that ice transport appeared to occur at an angle to the wind direction during his Arctic expedition during the 1890s. Ekman theory explains the state of circulation if water currents were driven only by the transfer of momentum from the wind. In the physical world, this is difficult to observe because of the influences of many simultaneous current driving forces, though the following theory technically applies to the idealized situation involving only wind forces, Ekman motion describes the wind-driven portion of circulation seen in the surface layer. Surface currents flow at a 45° angle to the due to a balance between the Coriolis force and the drags generated by the wind and the water. If the ocean is divided vertically into thin layers, the magnitude of the velocity decreases from a maximum at the surface until it dissipates, the direction also shifts slightly across each subsequent layer. This is called the Ekman spiral, the layer of water from the surface to the point of dissipation of this spiral is known as the Ekman layer. If all flow over the Ekman layer is integrated, the net transportation is at 90° to the right of the wind in the northern hemisphere. Some assumptions of the dynamics involved in the process must be made in order to simplify the process to a point where it is solvable. Here M x and M y represent the zonal and meridional mass transport terms with units of mass per time per unit length. Contrarily to common logic, north-south winds cause mass transport in the East-West direction, in order to understand the vertical velocity structure of the water column, equations 1 and 2 can be rewritten in terms of the vertical eddy viscosity term. ∂ τ x ∂ z = ρ A z ∂2 u ∂ z 2, ∂ τ y ∂ z = ρ A z ∂2 v ∂ z 2, where A z is the vertical eddy viscosity coefficient. This gives a set of equations of the form A z ∂2 u ∂ z 2 = − f v, A z ∂2 v ∂ z 2 = f u. In order to solve this system of two equations, two boundary conditions can be applied, →0 as z → ∞, friction is equal to wind stress at the free surface. Things can be simplified by considering wind blowing in the y-direction only. By solving this at z=0, the current is found to be 45 degrees to the right of the wind in the Northern Hemisphere. This also gives the shape of the Ekman spiral, both in magnitude and direction. Integrating these equations over the Ekman layer shows that the net Ekman transport term is 90 degrees to the right of the wind in the Northern Hemisphere
2.
Physical oceanography
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Physical oceanography is the study of physical conditions and physical processes within the ocean, especially the motions and physical properties of ocean waters. Physical oceanography is one of several sub-domains into which oceanography is divided, others include biological, chemical and geological oceanography. Physical oceanography may be subdivided into descriptive and dynamical physical oceanography, descriptive physical oceanography seeks to research the ocean through observations and complex numerical models, which describe the fluid motions as precise as possible. Dynamical physical oceanography focuses primarily upon the processes that govern the motion of fluids with emphasis upon theoretical research and these are part of the large field of Geophysical Fluid Dynamics that is shared together with meteorology. The fundamental role of the oceans in shaping Earth is acknowledged by ecologists, geologists, meteorologists, climatologists, an Earth without oceans would truly be unrecognizable. Roughly 97% of the water is in its oceans. The tremendous heat capacity of the oceans moderates the planets climate, the oceans influence extends even to the composition of volcanic rocks through seafloor metamorphism, as well as to that of volcanic gases and magmas created at subduction zones. Though this apparent discrepancy is great, for land and sea, the respective extremes such as mountains and trenches are rare. Because the vast majority of the oceans volume is deep water. The same percentage falls in a salinity range between 34–35 ppt, there is still quite a bit of variation, however. Surface temperatures can range from below freezing near the poles to 35 °C in restricted tropical seas, in terms of temperature, the oceans layers are highly latitude-dependent, the thermocline is pronounced in the tropics, but nonexistent in polar waters. The halocline usually lies near the surface, where evaporation raises salinity in the tropics and these variations of salinity and temperature with depth change the density of the seawater, creating the pycnocline. Energy for the ocean circulation comes from solar radiation and gravitational energy from the sun, perhaps three quarters of this heat is carried in the atmosphere, the rest is carried in the ocean. The atmosphere is heated from below, which leads to convection, by contrast the ocean is heated from above, which tends to suppress convection. Instead ocean deep water is formed in regions where cold salty waters sink in fairly restricted areas. This is the beginning of the thermohaline circulation, oceanic currents are largely driven by the surface wind stress, hence the large-scale atmospheric circulation is important to understanding the ocean circulation. The Hadley circulation leads to Easterly winds in the tropics and Westerlies in mid-latitudes and this leads to slow equatorward flow throughout most of a subtropical ocean basin. The return flow occurs in an intense, narrow, poleward western boundary current, like the atmosphere, the ocean is far wider than it is deep, and hence horizontal motion is in general much faster than vertical motion
3.
Wind
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Wind is the flow of gases on a large scale. On the surface of the Earth, wind consists of the movement of air. Winds are commonly classified by their scale, their speed, the types of forces that cause them, the regions in which they occur. The strongest observed winds on a planet in the Solar System occur on Neptune, Winds have various aspects, an important one being its velocity, another the density of the gas involved, another its energy content or wind energy. In meteorology, winds are referred to according to their strength. Short bursts of high speed wind are termed gusts, strong winds of intermediate duration are termed squalls. Long-duration winds have various names associated with their strength, such as breeze, gale, storm. The two main causes of large-scale atmospheric circulation are the differential heating between the equator and the poles, and the rotation of the planet, within the tropics, thermal low circulations over terrain and high plateaus can drive monsoon circulations. In coastal areas the sea breeze/land breeze cycle can define local winds, in areas that have variable terrain, mountain, Wind powers the voyages of sailing ships across Earths oceans. Hot air balloons use the wind to take trips, and powered flight uses it to increase lift. Areas of wind caused by various weather phenomena can lead to dangerous situations for aircraft. When winds become strong, trees and man-made structures are damaged or destroyed, Winds can shape landforms, via a variety of aeolian processes such as the formation of fertile soils, such as loess, and by erosion. Wind also affects the spread of wildfires, Winds can disperse seeds from various plants, enabling the survival and dispersal of those plant species, as well as flying insect populations. When combined with temperatures, wind has a negative impact on livestock. Wind affects animals food stores, as well as their hunting, Wind is caused by differences in the atmospheric pressure. When a difference in atmospheric pressure exists, air moves from the higher to the pressure area. On a rotating planet, air will also be deflected by the Coriolis effect, globally, the two major driving factors of large-scale wind patterns are the differential heating between the equator and the poles and the rotation of the planet. Outside the tropics and aloft from frictional effects of the surface, near the Earths surface, friction causes the wind to be slower than it would be otherwise
4.
Nutrient
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A nutrient is a component in foods that an organism uses to survive and grow. Macronutrients provide the energy an organisms metabolic system needs to function while micronutrients provide the necessary cofactors for metabolism to be carried out. Both types of nutrients can be acquired from the environment, micronutrients are used to build and repair tissues and to regulate body processes while macronutrients are converted to, and used for, energy. Methods of nutrient intake are different for plants and animals, plants take in nutrients directly from the soil through their roots and from the atmosphere through their leaves. Animals and protists have specialized digestive systems that work to break down macronutrients for energy, organic nutrients consist of carbohydrates, fats, proteins, and vitamins. Inorganic chemical compounds such as minerals, water, and oxygen may also be considered nutrients. A nutrient is considered if it must be obtained from an external source either because the organism cannot synthesize it or because insufficient quantities are produced. Nutrients needed in small amounts are called micronutrients while those needed in large quantities are called macronutrients. The effects of nutrients are dose-dependent, shortages are called deficiencies, macronutrients are defined in several different ways. The chemical elements humans consume in the largest quantities are carbon, hydrogen, nitrogen, oxygen, phosphorus, the classes of chemical compounds humans consume in the largest quantities and which provide bulk energy are carbohydrates, proteins, and fats. Water and atmospheric oxygen also must be consumed in large quantities, calcium, salt, magnesium, and potassium are sometimes added to the list of macronutrients because they are required in large quantities compared to other vitamins and minerals. They are sometimes referred to as the macrominerals, carbohydrates are compounds made up of types of sugars. Carbohydrates are classified by their number of units, monosaccharides, disaccharides, oligosaccharides. Proteins are organic compounds that consist of amino acids joined by peptide bonds, the body cannot manufacture some of the amino acids, the diet must supply them. Proteins, in nutrition, are broken down through digestion by proteases back into free amino acids, fats consist of a glycerin molecule with three fatty acids attached. Fatty acids are unbranched hydrocarbon chains,1 connected by single bonds alone or by double and single bonds. Fats are needed to keep cell membranes functioning properly, to insulate body organs against shock, to body temperature stable. The body does not manufacture certain fatty acids and the diet must supply them, although alcohol provides energy, and can thus be compared to macronutrients, it is not a substance that is essential for normal function
5.
Ocean
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An ocean is a body of saline water that composes much of a planets hydrosphere. On Earth, an ocean is one of the major divisions of the World Ocean. These are, in descending order by area, the Pacific, Atlantic, Indian, Southern, the word sea is often used interchangeably with ocean in American English but, strictly speaking, a sea is a body of saline water partly or fully enclosed by land. The ocean contains 97% of Earths water, and oceanographers have stated that less than 5% of the World Ocean has been explored, the total volume is approximately 1.35 billion cubic kilometers with an average depth of nearly 3,700 meters. As the world ocean is the component of Earths hydrosphere, it is integral to all known life, forms part of the carbon cycle. The world ocean is the habitat of 230,000 known species, but because much of it is unexplored, the origin of Earths oceans remains unknown, oceans are thought to have formed in the Hadean period and may have been the impetus for the emergence of life. Extraterrestrial oceans may be composed of water or other elements and compounds, the only confirmed large stable bodies of extraterrestrial surface liquids are the lakes of Titan, although there is evidence for the existence of oceans elsewhere in the Solar System. Early in their histories, Mars and Venus are theorized to have had large water oceans. The Mars ocean hypothesis suggests that nearly a third of the surface of Mars was once covered by water, compounds such as salts and ammonia dissolved in water lower its freezing point so that water might exist in large quantities in extraterrestrial environments as brine or convecting ice. Unconfirmed oceans are speculated beneath the surface of many planets and natural satellites, notably. The Solar Systems giant planets are thought to have liquid atmospheric layers of yet to be confirmed compositions. Oceans may also exist on exoplanets and exomoons, including surface oceans of water within a circumstellar habitable zone. Ocean planets are a type of planet with a surface completely covered with liquid. The concept of Ōkeanós has an Indo-European connection, Greek Ōkeanós has been compared to the Vedic epithet ā-śáyāna-, predicated of the dragon Vṛtra-, who captured the cows/rivers. Related to this notion, the Okeanos is represented with a dragon-tail on some early Greek vases, though generally described as several separate oceans, these waters comprise one global, interconnected body of salt water sometimes referred to as the World Ocean or global ocean. This concept of a body of water with relatively free interchange among its parts is of fundamental importance to oceanography. The major oceanic divisions – listed below in descending order of area and volume – are defined in part by the continents, various archipelagos, Oceans are fringed by smaller, adjoining bodies of water such as seas, gulfs, bays, bights, and straits. The Mid-Oceanic Ridge of the World are connected and form the Ocean Ridge, the continuous mountain range is 65,000 km long, and the total length of the oceanic ridge system is 80,000 km long
6.
Surface water
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Surface water is water on the surface of the planet such as in a river, lake, wetland, or ocean. It can be contrasted with groundwater and atmospheric water, non-saline surface water is replenished by precipitation and by recruitment from ground-water. Surface and groundwater are two entities, so they must be regarded as such. However, there is an ever-increasing need for management of the two as they are part of a system that is paramount when the demand for water exceeds the available supply. Depletion of surface and ground water sources for public consumption is caused by over-pumping, aquifers near river systems that are over-pumped have been known to deplete surface water sources as well. Research supporting this has found in numerous water budgets for a multitude of cities. Response times for an aquifer are long, however, a total ban on ground water usage during water recessions would allow surface water to retain better levels required for sustainable aquatic life. By reducing ground water pumping, the water supplies will be able to maintain their levels, as they recharge from direct precipitation, surface runoff. Environmental persistent pharmaceutical pollutant Meltwater Optimum water content for tillage Applied Hydrogeology, Fourth Edition by C. W. Fetter
7.
Phytoplankton
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Phytoplankton /ˌfaɪtoʊˈplæŋktən/ are the autotrophic components of the plankton community and a key part of oceans, seas and freshwater basin ecosystems. The name comes from the Greek words φυτόν, meaning plant, most phytoplankton are too small to be individually seen with the unaided eye. Phytoplankton are photosynthesizing microscopic organisms that inhabit the upper layer of almost all oceans. They are agents for primary production, the creation of organic compounds from carbon dioxide dissolved in the water, Phytoplankton obtain energy through the process of photosynthesis and must therefore live in the well-lit surface layer of an ocean, sea, lake, or other body of water. Phytoplankton account for half of all activity on Earth. Their cumulative energy fixation in carbon compounds is the basis for the vast majority of oceanic, the effects of anthropogenic warming on the global population of phytoplankton is an area of active research. Additionally, changes in the mortality of phytoplankton due to rates of zooplankton grazing may be significant, as a side note, one of the more remarkable food chains in the ocean – remarkable because of the small number of links – is that of phytoplankton-feeding krill feeding baleen whales. Phytoplankton are also dependent on minerals. However, across large regions of the World Ocean such as the Southern Ocean and this has led to some scientists advocating iron fertilization as a means to counteract the accumulation of human-produced carbon dioxide in the atmosphere. Large-scale experiments have added iron to the oceans to promote phytoplankton growth, however, controversy about manipulating the ecosystem and the efficiency of iron fertilization has slowed such experiments. Phytoplankton depend on other substances to survive as well, in particular, Vitamin B is crucial. Areas in the ocean have been identified as having a lack of Vitamin B. While almost all species are obligate photoautotrophs, there are some that are mixotrophic and other. Of these, the best known are dinoflagellate genera such as Noctiluca and Dinophysis, the term phytoplankton encompasses all photoautotrophic microorganisms in aquatic food webs. Phytoplankton serve as the base of the food web, providing an essential ecological function for all aquatic life. However, unlike terrestrial communities, where most autotrophs are plants, phytoplankton are a group, incorporating protistan eukaryotes. There are about 5,000 known species of marine phytoplankton, how such diversity evolved despite scarce resources is unclear. In terms of numbers, the most important groups of phytoplankton include the diatoms, cyanobacteria and dinoflagellates, one group, the coccolithophorids, is responsible for the release of significant amounts of dimethyl sulfide into the atmosphere
8.
Biomass
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Biomass is an industry term for getting energy by burning wood, and other organic matter. It has become popular among power stations, which switch from coal to biomass to comply with the law. Biomass most often refers to plants or plant-based materials that are not used for food or feed, as an energy source, biomass can either be used directly via combustion to produce heat, or indirectly after converting it to various forms of biofuel. Conversion of biomass to biofuel can be achieved by different methods which are classified into, thermal, chemical. Historically, humans have harnessed biomass-derived energy since the time people began burning wood to make fire. Even today, biomass is the source of fuel for domestic use in many developing countries. Biomass is all biologically-produced matter based in carbon, hydrogen and oxygen, the estimated biomass production in the world is 104.9 petagrams of carbon per year, about half in the ocean and half on land. Wood remains the largest biomass energy source today, examples include forest residues, yard clippings, wood chips, wood energy is derived by using lignocellulosic biomass as fuel. Harvested wood may be used directly as a fuel or collected from waste streams to be processed into pellet fuel or other forms of fuels. The largest source of energy from wood is pulping liquor or black liquor, in the second sense, biomass includes plant or animal matter that can be converted into fibers or other industrial chemicals, including biofuels. Based on the source of biomass, biofuels are classified broadly into two major categories, first-generation biofuels are derived from sources such as sugarcane and corn starch. Sugars present in this biomass are fermented to produce bioethanol, a fuel which can be used directly in a fuel cell to produce electricity or serve as an additive to gasoline. However, utilizing food-based resources for production only aggravates the food shortage problem. Second-generation biofuels, on the hand, utilize non-food-based biomass sources such as agriculture. These biofuels mostly consist of lignocellulosic biomass, which is not edible and is a waste for many industries. Despite being the alternative, economical production of second-generation biofuel is not yet achieved due to technological issues. These issues arise due to chemical inertness and structural rigidity of lignocellulosic biomass. Plant energy is produced by crops grown for use as fuel that offer high biomass output per hectare with low input energy
9.
Sea surface temperature
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Sea surface temperature is the water temperature close to the oceans surface. The exact meaning of surface varies according to the measurement method used, air masses in the Earths atmosphere are highly modified by sea surface temperatures within a short distance of the shore. Localized areas of snow can form in bands downwind of warm water bodies within an otherwise cold air mass. Warm sea surface temperatures are known to be a cause of tropical cyclogenesis over the Earths oceans, tropical cyclones can also cause a cool wake, due to turbulent mixing of the upper 30 metres of the ocean. SST changes diurnally, like the air above it, but to a lesser degree, there is less SST variation on breezy days than on calm days. Coastal SSTs can cause winds to generate upwelling, which can significantly cool or warm nearby landmasses. Onshore winds can cause a considerable warm-up even in areas where upwelling is fairly constant and its values are important within numerical weather prediction as the SST influences the atmosphere above, such as in the formation of sea breezes and sea fog. It is also used to calibrate measurements from weather satellites, there are a variety of techniques for measuring this parameter that can potentially yield different results because different things are actually being measured. Away from the sea surface, general temperature measurements are accompanied by a reference to the specific depth of measurement. Sea surface temperature measurements are confined to the top portion of the ocean, SST was one of the first oceanographic variables to be measured. Benjamin Franklin suspended a mercury thermometer from a ship travelling between the United States and Europe in his survey of the Gulf stream in the late eighteenth century. SST was later measured by dipping a thermometer into a bucket of water that was drawn from the sea surface. The first automated technique for determining SST was accomplished by measuring the temperature of water in the port of large ships. These observations have a bias of around 0.6 °C due to the heat of the engine room. This bias has led to changes in the perception of global warming since 2000, fixed weather buoys measure the water temperature at a depth of 3 metres. Measurements of SST have had inconsistencies over the last 130 years due to the way they were taken, in the nineteenth century, measurements were taken in a bucket off of a ship. However, there was a variation in temperature because of the differences in buckets. Samples were collected in either a wood or a canvas bucket
10.
Chlorophyll a
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Chlorophyll a is a specific form of chlorophyll used in oxygenic photosynthesis. It absorbs most energy from wavelengths of violet-blue and orange-red light and it also reflects green/yellow light, and as such contributes to the observed green color of most plants. This photosynthetic pigment is essential for photosynthesis in eukaryotes, cyanobacteria, Chlorophyll a also transfers resonance energy in the antenna complex, ending in the reaction center where specific chlorophylls P680 and P700 are located. Chlorophyll a is essential for most photosynthetic organisms to release energy but is not the only pigment that can be used for photosynthesis. All oxygenic photosynthetic organisms use chlorophyll a, but differ in accessory pigments like chlorophylls b, Chlorophyll a can also be found in very small quantities in the green sulfur bacteria, an anaerobic photoautotroph. These organisms use bacteriochlorophyll and some chlorophyll a but do not produce oxygen, anoxygenic photosynthesis is the term applied to this process, unlike oxygenic photosynthesis where oxygen is produced during the light reactions of photosynthesis. The molecular structure of chlorophyll a consists of a ring, whose four nitrogen atoms surround a central magnesium atom, and has several other attached side chains. Chlorophyll a contains a magnesium ion encased in a ring structure known as a chlorin. The chlorin ring is a compound derived from pyrrole. Four nitrogen atoms from the surround and bind the magnesium atom. The magnesium center uniquely defines the structure as a chlorophyll molecule, the porphyrin ring of bacteriochlorophyll is saturated, and lacking alternation of double and single bonds causing variation in absorption of light. Side chains are attached to the ring of the various chlorophyll molecules. Different side chains characterize each type of molecule, and alters the absorption spectrum of light. For instance, the difference between Chlorophyll a and Chlorophyll b is that Chlorophyll b has an aldehyde instead of a methyl group at the C-7 position. Chlorophyll a has a hydrophobic tail, which anchors the molecule to other hydrophobic proteins in the thylakoid membrane of the chloroplast. Once detached from the ring, this long hydrocarbon tail becomes the precursor of two biomarkers, pristane and phytane. Both of which are important in the study of geochemistry and the determination of petroleum sources, Chlorophyll a biosynthetic pathway utilizes a variety of enzymes. Genes code for the enzymes on the Mg-tetrapyrroles of both bacteriochlorophyll a and chlorophyll a and it begins with glutamic acid, which is transformed into a 5-aminolevulinic acid
11.
Primary production
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In ecology, primary production is the synthesis of organic compounds from atmospheric or aqueous carbon dioxide. Almost all life on Earth relies directly or indirectly on primary production, the organisms responsible for primary production are known as primary producers or autotrophs, and form the base of the food chain. In terrestrial ecoregions, these are mainly plants, while in aquatic ecoregions algae predominate in this role, ecologists distinguish primary production as either net or gross, the former accounting for losses to processes such as cellular respiration, the latter not. Primary production is the production of energy in organic compounds by living organisms. The main source of energy is sunlight but a minute fraction of primary production is driven by lithotrophic organisms using the chemical energy of inorganic molecules. Regardless of its source, this energy is used to complex organic molecules from simpler inorganic compounds such as carbon dioxide. Consumption of primary producers by heterotrophic organisms, such as animals, then transfers these organic molecules up the food web, gross primary production is the amount of chemical energy as biomass that primary producers create in a given length of time. Some fraction of this energy is used by primary producers for cellular respiration. The remaining fixed energy is referred to as net primary production, some net primary production goes toward growth and reproduction of primary producers, while some is consumed by herbivores. Both gross and net primary production are in units of mass per area per unit time interval. In terrestrial ecosystems, mass of carbon per area per year is most often used as the unit of measurement. On the land, almost all production is now performed by vascular plants, with a small fraction coming from algae and non-vascular plants such as mosses. Before the evolution of plants, non-vascular plants likely played a more significant role. Primary production on land is a function of many factors, but principally local hydrology, while plants cover much of the Earths surface, they are strongly curtailed wherever temperatures are too extreme or where necessary plant resources are limiting, such as deserts or polar regions. Water is consumed in plants by the processes of photosynthesis and transpiration, the latter process is driven by the evaporation of water from the leaves of plants. Transpiration allows plants to transport water and mineral nutrients from the soil to growth regions, diffusion of water vapour out of a leaf, the force that drives transpiration, is regulated by structures known as stomata. These structure also regulate the diffusion of carbon dioxide from the atmosphere into the leaf, certain plants use alternative forms of photosynthesis, called Crassulacean acid metabolism and C4. In a reversal of the pattern on land, in the oceans, almost all photosynthesis is performed by algae, with a small fraction contributed by vascular plants, algae encompass a diverse range of organisms, ranging from single floating cells to attached seaweeds
12.
Fishery
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Generally, a fishery is an entity engaged in raising or harvesting fish which is determined by some authority to be a fishery. The definition often includes a combination of fish and fishers in a region, a fishery may involve the capture of wild fish or raising fish through fish farming or aquaculture. Directly or indirectly, the livelihood of over 500 million people in developing countries depends on fisheries, overfishing, including the taking of fish beyond sustainable levels, is reducing fish stocks and employment in many world regions. In biology – the term fish is most strictly used to any animal with a backbone that has gills throughout life and has limbs, if any. Many types of animals commonly referred to as fish are not fish in this strict sense. In fisheries – the term fish is used as a collective term, true fish – The strict biological definition of a fish, above, is sometimes called a true fish. True fish are referred to as finfish or fin fish to distinguish them from other aquatic life harvested in fisheries or aquaculture. Fisheries are harvested for their value and they can be saltwater or freshwater, wild or farmed. Examples are the salmon fishery of Alaska, the cod fishery off the Lofoten islands, capture fisheries can be broadly classified as industrial scale, small-scale or artisanal, and recreational. Close to 90% of the fishery catches come from oceans. These marine catches have remained stable since the mid-nineties. Most marine fisheries are based near the coast, however, productive wild fisheries also exist in open oceans, particularly by seamounts, and inland in lakes and rivers. Most fisheries are fisheries, but farmed fisheries are increasing. Farming can occur in areas, such as with oyster farms. There are species fisheries worldwide for finfish, mollusks, crustaceans and echinoderms, however, a very small number of species support the majority of the world’s fisheries. Some of these species are herring, cod, anchovy, tuna, flounder, mullet, squid, shrimp, salmon, crab, lobster, oyster and scallops. All except these last four provided a catch of well over a million tonnes in 1999, with herring. Many other species are harvested in smaller numbers, cullis-Suzuki S and Pauly D Failing the high seas, A global evaluation of regional fisheries management organizations Marine Policy,34 pp 1036–1042
13.
Fish
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A fish is any member of a group of animals that consist of all gill-bearing aquatic craniate animals that lack limbs with digits. They form a group to the tunicates, together forming the olfactores. Included in this definition are the living hagfish, lampreys, and cartilaginous, tetrapods emerged within lobe-finned fishes, so cladistically they are fish as well. However, traditionally fish are rendered obsolete or paraphyletic by excluding the tetrapods, because in this manner the term fish is defined negatively as a paraphyletic group, it is not considered a formal taxonomic grouping in systematic biology. The traditional term pisces is considered a typological, but not a phylogenetic classification, the earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts, fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators, the first fish with jaws appeared in the Silurian period, after which many became formidable marine predators rather than just the prey of arthropods. Fish are abundant in most bodies of water and they can be found in nearly all aquatic environments, from high mountain streams to the abyssal and even hadal depths of the deepest oceans. With 33,100 described species, fish exhibit greater species diversity than any group of vertebrates. Fish are an important resource for humans worldwide, especially as food, commercial and subsistence fishers hunt fish in wild fisheries or farm them in ponds or in cages in the ocean. They are also caught by fishers, kept as pets, raised by fishkeepers. Fish have had a role in culture through the ages, serving as deities, religious symbols, fish do not represent a monophyletic group, and therefore the evolution of fish is not studied as a single event. Early fish from the record are represented by a group of small, jawless. Jawless fish lineages are mostly extinct, an extant clade, the lampreys may approximate ancient pre-jawed fish. The first jaws are found in Placodermi fossils, the diversity of jawed vertebrates may indicate the evolutionary advantage of a jawed mouth. It is unclear if the advantage of a hinged jaw is greater biting force, improved respiration, fish may have evolved from a creature similar to a coral-like sea squirt, whose larvae resemble primitive fish in important ways. The first ancestors of fish may have kept the form into adulthood. Fish are a group, that is, any clade containing all fish also contains the tetrapods
14.
Ocean current
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Depth contours, shoreline configurations, and interactions with other currents influence a currents direction and strength. Therefore ocean currents are primarily horizontal water movements, Ocean currents flow for great distances, and together, create the global conveyor belt which plays a dominant role in determining the climate of many of the Earth’s regions. More specifically, ocean currents influence the temperature of the regions through which they travel, for example, warm currents traveling along more temperate coasts increase the temperature of the area by warming the sea breezes that blow over them. Perhaps the most striking example is the Gulf Stream, which makes northwest Europe much more temperate than any region at the same latitude. Another example is Lima, Peru where the climate is cooler than the tropical latitudes in which the area is located, in these wind driven currents, the Ekman spiral effect results in the currents flowing at an angle to the driving winds. In addition, the areas of ocean currents move somewhat with the seasons. Deep ocean basins generally have a surface current, in that the eastern equatorward-flowing branch is broad. These western boundary currents are a consequence of the rotation of the Earth, Deep ocean currents are driven by density and temperature gradients. Thermohaline circulation is known as the oceans conveyor belt. These currents, called submarine rivers, flow under the surface of the ocean and are hidden from immediate detection, where significant vertical movement of ocean currents is observed, this is known as upwelling and downwelling. Deep ocean currents are currently being researched using a fleet of robots called Argo. The South Equatorial Currents of the Atlantic and Pacific straddle the equator, though the Coriolis effect is weak near the equator, water moving in the currents on either side of the equator is deflected slightly poleward and replaced by deeper water. Thus, equatorial upwelling occurs in these westward flowing equatorial surface currents, upwelling is an important process because this water from within and below the pycnocline is often rich in nutrients and greatly benefits the growth of marine organisms. By contrast, generally poor conditions for growth prevail in most of the tropical ocean because strong layering isolates deep. Ocean currents are measured in sverdrup, where 1 sv is equivalent to a flow rate of 1,000,000 m3 per second. Surface currents are found on the surface of an ocean, and are driven by large scale wind currents and they are directly affected by the wind—the Coriolis effect plays a role in their behaviors. Horizontal and vertical currents also exist below the pycnocline in the deeper waters. The movement of water due to differences in density as a function of water temperature, ripple marks in sediments, scour lines, and the erosion of rocky outcrops on deep-ocean floors are evidence that relatively strong, localized bottom currents exist
15.
Coriolis force
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In physics, the Coriolis force is an inertial force that acts on objects that are in motion relative to a rotating reference frame. In a reference frame with clockwise rotation, the acts to the left of the motion of the object. In one with anticlockwise rotation, the acts to the right. Early in the 20th century, the term Coriolis force began to be used in connection with meteorology, deflection of an object due to the Coriolis force is called the Coriolis effect. Newtons laws of motion describe the motion of an object in a frame of reference. When Newtons laws are transformed to a frame of reference. Both forces are proportional to the mass of the object, the Coriolis force is proportional to the rotation rate and the centrifugal force is proportional to its square. The Coriolis force acts in a perpendicular to the rotation axis. The centrifugal force acts outwards in the direction and is proportional to the distance of the body from the axis of the rotating frame. These additional forces are termed inertial forces, fictitious forces or pseudo forces and they allow the application of Newtons laws to a rotating system. They are correction factors that do not exist in a non-accelerating or inertial reference frame, a commonly encountered rotating reference frame is the Earth. The Coriolis effect is caused by the rotation of the Earth, such motions are constrained by the surface of the Earth, so only the horizontal component of the Coriolis force is generally important. This force causes moving objects on the surface of the Earth to be deflected to the right in the Northern Hemisphere, the horizontal deflection effect is greater near the poles, since the effective rotation rate about a local vertical axis is largest there, and smallest at the equator. This effect is responsible for the rotation of large cyclones, riccioli, Grimaldi, and Dechales all described the effect as part of an argument against the heliocentric system of Copernicus. In other words, they argued that the Earths rotation should create the effect, the effect was described in the tidal equations of Pierre-Simon Laplace in 1778. Gaspard-Gustave Coriolis published a paper in 1835 on the yield of machines with rotating parts. That paper considered the forces that are detected in a rotating frame of reference. Coriolis divided these forces into two categories
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Ekman spiral
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The Ekman spiral is a structure of currents or winds near a horizontal boundary in which the flow direction rotates as one moves away from the boundary. It derives its name from the Swedish oceanographer Vagn Walfrid Ekman, the deflection of surface currents was first noticed by the Norwegian oceanographer Fridtjof Nansen during the Fram expedition and the effect was first physically explained by Vagn Walfrid Ekman. The effect is a consequence of the Coriolis effect which subjects moving objects to a force to the right of their direction of motion in the northern hemisphere. As the flow is now somewhat right of the wind, the Coriolis force perpendicular to the motion is now partly directed against the wind. The depth to which the Ekman spiral penetrates is determined by how far turbulent mixing can penetrate over the course of a pendulum day, the diagram above attempts to show the forces associated with the Ekman spiral as applied to the Northern hemisphere. The first documented observations of an oceanic Ekman spiral were made in the Arctic Ocean from an ice floe in 1958. Though in the Southern Ocean the compression, or spiral flattening effect disappeared when new data permitted a more careful treatment of the effect of geostrophic shear, the classic Ekman spiral has been observed under sea ice, but observations remain rare in open-ocean conditions. This is due both to the fact that the turbulent mixing in the layer of the ocean has a strong diurnal cycle. Ekman spirals are found in the atmosphere. Surface winds in the Northern Hemisphere tend to blow to the left of winds aloft, Ekman transport Ekman layer Secondary flow Upwelling AMS Glossary, mathematical description A. Gnanadesikan and R. A. Weller,1995 · Structure and instability of the Ekman spiral in the presence of gravity waves · Journal of Physical Oceanography 25. Weller and R. Pinkel,1986 · Diurnal cycling, Observations and models of the upper ocean response to heating, cooling and wind mixing · Journal of Geophysical Research 91. Davis,1987 · Measurements of near-surface shear in the ocean · Journal of Geophysical Research 92, pp. 2851–2858. Field, J. G. C. L. Griffiths, E. A. S. Linley, P. Zoutendyk and R. Carter,1981 Wind-induced water movements in a Benguela kelp bed
17.
Nitrate
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Nitrate is a polyatomic ion with the molecular formula NO−3 and a molecular mass of 62.0049 g/mol. Nitrates also describe the functional group RONO2. These nitrate esters are a class of explosives. The anion is the base of nitric acid, consisting of one central nitrogen atom surrounded by three identically bonded oxygen atoms in a trigonal planar arrangement. The nitrate ion carries a charge of −1. This arrangement is used as an example of resonance. Like the isoelectronic carbonate ion, the ion can be represented by resonance structures. A common example of a nitrate salt is potassium nitrate. A rich source of nitrate in the human body comes from diets rich in leafy green foods, such as spinach. NO3- is the active component within beetroot juice and other vegetables. Nitrite and water are converted in the body to nitric oxide, nitrate salts are found naturally on earth as large deposits, particularly of nitratine, a major source of sodium nitrate. Nitrates are found in man-made fertilizers, as a byproduct of lightning strikes in earths nitrogen-oxygen rich atmosphere, nitric acid is produced when nitrogen dioxide reacts with water vapor. Nitrates are mainly produced for use as fertilizers in agriculture because of their solubility and biodegradability. The main nitrate fertilizers are ammonium, sodium, potassium, several million kilograms are produced annually for this purpose. The second major application of nitrates is as oxidizing agents, most notably in explosives where the oxidation of carbon compounds liberates large volumes of gases. Sodium nitrate is used to air bubbles from molten glass. Mixtures of the salt are used to harden some metals. Explosives and table tennis balls are made from celluloid, although nitrites are the nitrogen compound chiefly used in meat curing, nitrates are used in certain specialty curing processes where a long release of nitrite from parent nitrate stores is needed
18.
Silicic acid
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Silicic acid /sɪˈlɪsɪk ˌæsɪd/ is a chemical compound. Silicic acid is the name for a family of chemical compounds containing the element silicon attached to oxide. This family of compounds have the formula n. In general, silicic acid reactions are difficult to control, partial dehydration to metasilicic acid, for example, is challenging because the reaction typically progresses all the way to silicon dioxide and water. Like other silanols, silicic acid is a weak acid and it can be deprotonated in solution, the conjugate base silicate is known. Silicic acid was discovered by Jöns Jacob Berzelius between 1810 and 1836 when studying silicon generated by his experiments, however, he failed to recognise it as distinct from silicon dioxide. Naturally occurring silicic acid is produced by a process called hydration involving water, and quartz. The reaction producing silicic acid from quartz can be written as, if the products are left in air dry products are formed. Silicic acid can be produced by the acidification of sodium silicate in aqueous solution, the main problem in using silicic acids in chemical synthesis is that silicic acids readily lose water to form randomly polymeric silica gel, a form of silicon dioxide. Dissolved silica is a used in the field of oceanography to describe the form of water-soluble silica as silicon hydroxide which can be measured by standard analyses. However, the dissolved silica excludes silicate occurring as silicate minerals, which is a class of minerals forming rings, sheets, chains. Likewise, the dissolved silica is different from the term silicone. There exist three different species of DSi in natural waters, SiO222− SiO3− Si4 DSi is created near the oceans surface and it is carried into the abyssopelagic zone by falling water in the poles. Uncontrolled build-up of silicic acid in the ocean is naturally checked – although human influence can upset this natural regulation and it is primarily removed by conversion to silicon dioxide and water. In the oceans, silicon exists primarily as orthosilicic acid, and these algae polymerise the silicic acid to so-called biogenic silica, used to construct their cell walls. In the uppermost water column the surface ocean is undersaturated with respect to DSi, DSi is regenerated with increasing water depth, and DSi values increase along the conveyor belt from the Atlantic over the Indian into the Pacific Ocean. Study has shown that physiological concentration of orthosilicic acid stimulates collagen type 1 synthesis, choline-stabilized orthosilicic acid is a bioavailable nutritional supplement. Bioinorganic Chemistry of Aluminium and Silicon research group website
19.
Decomposition
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Decomposition is the process by which organic substances are broken down into simpler matter. The process is a part of nutrient cycle and is essential for recycling the matter that occupies physical space in the biosphere. Bodies of living organisms begin to decompose shortly after death, animals, such as worms, also help decompose the organic materials. Organisms that do this are known as decomposers, although no two organisms decompose in the same way, they all undergo the same sequential stages of decomposition. The science which studies decomposition is referred to as taphonomy from the Greek word τάφος taphos. One can differentiate abiotic from biotic decomposition, the former means degradation of a substance by chemical or physical processes, e. g. hydrolysis. The latter means the metabolic breakdown of materials into simpler components by living organisms and these processes release gases, such as cadaverine and putrescine, that are the chief source of the unmistakably putrid odor of decaying animal tissue. Prime decomposers are bacteria or fungi, though larger scavengers also play an important role in decomposition if the body is accessible to insects, mites and other animals. The most important arthropods that are involved in the process include carrion beetles, mites, the most important non-insect animals that are typically involved in the process include mammal and bird scavengers, such as coyotes, dogs, wolves, foxes, rats, crows and vultures. Some of these scavengers also remove and scatter bones, which they ingest at a later time, aquatic and marine environments have break-down agents that include bacteria, fish, crustaceans, Diptera larvae and other carrion scavengers. Five general stages are used to describe the process of decomposition in vertebrate animals, fresh, bloat, active and advanced decay, the general stages of decomposition are coupled with two stages of chemical decomposition, autolysis and putrefaction. These two stages contribute to the process of decomposition, which breaks down the main components of the body. The fresh stage begins immediately after the heart stops beating, from the moment of death, the body begins cooling or warming to match the temperature of the ambient environment, during a stage called algor mortis. Shortly after death, within three to six hours, the tissues become rigid and incapable of relaxing, during a stage called rigor mortis. Once the heart stops, the blood can no longer supply oxygen or remove carbon dioxide from the tissues and this process is known as autolysis. Visible changes caused by decomposition are limited during the fresh stage and these multiply, consuming the bodys carbohydrates, lipids, and proteins, to produce a variety of substances including propionic acid, lactic acid, methane, hydrogen sulfide, and ammonia. The process of microbial proliferation within a body is referred to as putrefaction and leads to the stage of decomposition. Blowflies and flesh flies are the first carrion insects to arrive, the bloat stage provides the first clear visual sign that microbial proliferation is underway
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Sun
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The Sun is the star at the center of the Solar System. It is a perfect sphere of hot plasma, with internal convective motion that generates a magnetic field via a dynamo process. It is by far the most important source of energy for life on Earth. Its diameter is about 109 times that of Earth, and its mass is about 330,000 times that of Earth, accounting for about 99. 86% of the total mass of the Solar System. About three quarters of the Suns mass consists of hydrogen, the rest is mostly helium, with smaller quantities of heavier elements, including oxygen, carbon, neon. The Sun is a G-type main-sequence star based on its spectral class and it formed approximately 4.6 billion years ago from the gravitational collapse of matter within a region of a large molecular cloud. Most of this matter gathered in the center, whereas the rest flattened into a disk that became the Solar System. The central mass became so hot and dense that it eventually initiated nuclear fusion in its core and it is thought that almost all stars form by this process. The Sun is roughly middle-aged, it has not changed dramatically for more than four billion years and it is calculated that the Sun will become sufficiently large enough to engulf the current orbits of Mercury, Venus, and probably Earth. The enormous effect of the Sun on Earth has been recognized since prehistoric times, the synodic rotation of Earth and its orbit around the Sun are the basis of the solar calendar, which is the predominant calendar in use today. The English proper name Sun developed from Old English sunne and may be related to south, all Germanic terms for the Sun stem from Proto-Germanic *sunnōn. The English weekday name Sunday stems from Old English and is ultimately a result of a Germanic interpretation of Latin dies solis, the Latin name for the Sun, Sol, is not common in general English language use, the adjectival form is the related word solar. The term sol is used by planetary astronomers to refer to the duration of a solar day on another planet. A mean Earth solar day is approximately 24 hours, whereas a mean Martian sol is 24 hours,39 minutes, and 35.244 seconds. From at least the 4th Dynasty of Ancient Egypt, the Sun was worshipped as the god Ra, portrayed as a falcon-headed divinity surmounted by the solar disk, and surrounded by a serpent. In the New Empire period, the Sun became identified with the dung beetle, in the form of the Sun disc Aten, the Sun had a brief resurgence during the Amarna Period when it again became the preeminent, if not only, divinity for the Pharaoh Akhenaton. The Sun is viewed as a goddess in Germanic paganism, Sól/Sunna, in ancient Roman culture, Sunday was the day of the Sun god. It was adopted as the Sabbath day by Christians who did not have a Jewish background, the symbol of light was a pagan device adopted by Christians, and perhaps the most important one that did not come from Jewish traditions
21.
Organic compound
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An organic compound is virtually any chemical compound that contains carbon, although a consensus definition remains elusive and likely arbitrary. Organic compounds are rare terrestrially, but of importance because all known life is based on organic compounds. The most basic petrochemicals are considered the building blocks of organic chemistry, for historical reasons discussed below, a few types of carbon-containing compounds, such as carbides, carbonates, simple oxides of carbon, and cyanides are considered inorganic. The distinction between organic and inorganic compounds, while useful in organizing the vast subject of chemistry. Organic chemistry is the science concerned with all aspects of organic compounds, Organic synthesis is the methodology of their preparation. The word organic is historical, dating to the 1st century, for many centuries, Western alchemists believed in vitalism. This is the theory that certain compounds could be synthesized only from their classical elements—earth, water, air, vitalism taught that these organic compounds were fundamentally different from the inorganic compounds that could be obtained from the elements by chemical manipulation. Vitalism survived for a while even after the rise of modern atomic theory and it first came under question in 1824, when Friedrich Wöhler synthesized oxalic acid, a compound known to occur only in living organisms, from cyanogen. A more decisive experiment was Wöhlers 1828 synthesis of urea from the inorganic salts potassium cyanate, urea had long been considered an organic compound, as it was known to occur only in the urine of living organisms. Wöhlers experiments were followed by others, in which increasingly complex organic substances were produced from inorganic ones without the involvement of any living organism. Even though vitalism has been discredited, scientific nomenclature retains the distinction between organic and inorganic compounds, still, even the broadest definition requires excluding alloys that contain carbon, including steel. The C-H definition excludes compounds that are considered organic, neither urea nor oxalic acid is organic by this definition, yet they were two key compounds in the vitalism debate. The IUPAC Blue Book on organic nomenclature specifically mentions urea and oxalic acid, other compounds lacking C-H bonds but traditionally considered organic include benzenehexol, mesoxalic acid, and carbon tetrachloride. Mellitic acid, which contains no C-H bonds, is considered an organic substance in Martian soil. The C-H bond-only rule also leads to somewhat arbitrary divisions in sets of carbon-fluorine compounds, for example, CF4 would be considered by this rule to be inorganic, whereas CF3H would be organic. Organic compounds may be classified in a variety of ways, one major distinction is between natural and synthetic compounds. Another distinction, based on the size of organic compounds, distinguishes between small molecules and polymers, natural compounds refer to those that are produced by plants or animals. Many of these are extracted from natural sources because they would be more expensive to produce artificially
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Photosynthesis
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Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that can later be released to fuel the organisms activities. In most cases, oxygen is released as a waste product. Most plants, most algae, and cyanobacteria perform photosynthesis, such organisms are called photoautotrophs, in plants, these proteins are held inside organelles called chloroplasts, which are most abundant in leaf cells, while in bacteria they are embedded in the plasma membrane. In these light-dependent reactions, some energy is used to strip electrons from suitable substances, such as water, in the Calvin cycle, atmospheric carbon dioxide is incorporated into already existing organic carbon compounds, such as ribulose bisphosphate. Using the ATP and NADPH produced by the light-dependent reactions, the compounds are then reduced and removed to form further carbohydrates. Cyanobacteria appeared later, the oxygen they produced contributed directly to the oxygenation of the Earth. Today, the rate of energy capture by photosynthesis globally is approximately 130 terawatts. Photosynthetic organisms also convert around 100–115 thousand million tonnes of carbon into biomass per year. Photosynthetic organisms are photoautotrophs, which means that they are able to synthesize food directly from carbon dioxide, however, not all organisms that use light as a source of energy carry out photosynthesis, photoheterotrophs use organic compounds, rather than carbon dioxide, as a source of carbon. In plants, algae, and cyanobacteria, photosynthesis releases oxygen and this is called oxygenic photosynthesis and is by far the most common type of photosynthesis used by living organisms. Although there are differences between oxygenic photosynthesis in plants, algae, and cyanobacteria, the overall process is quite similar in these organisms. There are also varieties of anoxygenic photosynthesis, used mostly by certain types of bacteria. Carbon dioxide is converted into sugars in a process called carbon fixation, photosynthesis provides the energy in the form of free electrons that are used to split carbon from carbon dioxide that is then used to fix that carbon once again as carbohydrate. Carbon fixation is a redox reaction, so photosynthesis supplies the energy that drives both process. In the first stage, light-dependent reactions or light reactions capture the energy of light and use it to make the energy-storage molecules ATP, during the second stage, the light-independent reactions use these products to capture and reduce carbon dioxide. Most organisms that utilize oxygenic photosynthesis use visible light for the light-dependent reactions, some organisms employ even more radical variants of photosynthesis. Some archea use a method that employs a pigment similar to those used for vision in animals. The bacteriorhodopsin changes its configuration in response to sunlight, acting as a proton pump and this produces a proton gradient more directly, which is then converted to chemical energy
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Food chain
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A food chain is a linear network of links in a food web starting from producer organisms and ending at apex predator species, detritivores, or decomposer species. A food chain also shows how the organisms are related with each other by the food they eat, each level of a food chain represents a different trophic level. A food chain differs from a web, because the complex network of different animals feeding relations are aggregated. Natural interconnections between food chains make it a food web, a common metric used to quantify food web trophic structure is food chain length. Food chains are used in ecological modeling. They are simplified abstractions of real food webs, but complex in their dynamics, food chain studies have an important role in ecotoxicology studies tracing the pathways and biomagnification of environmental contaminants. Producers, such as plants, are organisms that utilize solar or chemical energy to synthesize starch, all food chains must start with a producer. In the deep sea, food chains centered on hydrothermal vents, chemosynthetic bacteria and archaea use hydrogen sulfide and methane from hydrothermal vents and cold seeps as an energy source to produce carbohydrates, they form the base of the food chain. Consumers are organisms that eat other organisms, all organisms in a food chain, except the first organism, are consumers. Autotroph Heterotroph Lithotroph Trophic pyramid Predator-prey interaction
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Zooplankton
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Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word zooplankton is derived from the Greek zoon, meaning animal, individual zooplankton are usually microscopic, but some are larger and visible with the naked eye. Zooplankton is a categorization spanning a range of organism sizes including small protozoans, although zooplankton are primarily transported by ambient water currents, many have locomotion, used to avoid predators or to increase prey encounter rate. Ecologically important protozoan zooplankton groups include the foraminiferans, radiolarians and dinoflagellates and this wide phylogenetic range includes a similarly wide range in feeding behavior, filter feeding, predation and symbiosis with autotrophic phytoplankton as seen in corals. Zooplankton feed on bacterioplankton, phytoplankton, other zooplankton, detritus, as a result, zooplankton are primarily found in surface waters where food resources are abundant. Just as any species can be limited within a geographical region, however, species of zooplankton are not dispersed uniformly or randomly within a region of the ocean. As with phytoplankton, ‘patches’ of zooplankton species exist throughout the ocean, zooplankton patchiness can also be influenced by biological factors, as well as other physical factors. Biological factors include breeding, predation, concentration of phytoplankton, the physical factor that influences zooplankton distribution the most is mixing of the water column that affects nutrient availability and, in turn, phytoplankton production. Since they are small, zooplankton can respond rapidly to increases in phytoplankton abundance, for instance. Zooplankton can also act as a disease reservoir, crustacean zooplankton have been found to house the bacterium Vibrio cholerae, which causes cholera, by allowing the cholera vibrios to attach to their chitinous exoskeletons. This symbiotic relationship enhances the ability to survive in an aquatic environment, as the exoskeleton provides the bacterium with carbon. A global coverage database of zooplankton biomass and abundance data
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Filter feeder
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Some animals that use this method of feeding are clams, krill, sponges, baleen whales, and many fish. Some birds, such as flamingos and certain species of duck, are filter feeders. Filter feeders can play an important role in clarifying water, and are therefore considered ecosystem engineers, most forage fish are filter feeders. For example, the Atlantic menhaden, a type of herring, adult menhaden can filter up to four gallons of water a minute and play an important role in clarifying ocean water. They are also a check to the deadly red tide. In addition to bony fish, four types of cartilaginous fishes are also filter feeders. The whale shark sucks in a mouthful of water, closes its mouth, during the slight delay between closing the mouth and opening the gill flaps, plankton is trapped against the dermal denticles which line its gill plates and pharynx. This fine sieve-like apparatus, which is a modification of the gill rakers, prevents the passage of anything. Any material caught in the filter between the bars is swallowed. Whale sharks have been observed coughing and it is presumed that this is a method of clearing a build up of particles in the gill rakers. The megamouth shark has luminous organs called photophores around its mouth and it is believed they may exist to lure plankton or small fish into its mouth. The basking shark is a filter feeder, filtering zooplankton, small fish. Unlike the megamouth and whale sharks, the shark does not appear to actively seek its quarry. Unlike the other filter feeders, it relies only on the water that is pushed through the gills by swimming. Manta rays can time their arrival at the spawning of large shoals of fish and feed on the free-floating eggs and this stratagem is also employed by whale sharks. Mysidacea are small crustaceans that live close to shore and hover above the sea floor and they are an important food source for herring, cod, flounder, and striped bass. Mysids have a resistance to toxins in polluted areas. Antarctic krill manages to directly utilize the minute phytoplankton cells, which no other animal of krill size can do
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Canary Current
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The Canary Current is a wind-driven surface current that is part of the North Atlantic Gyre. This eastern boundary current branches south from the North Atlantic Current and flows southwest about as far as Senegal where it turns west, the current is named after the Canary Islands. The archipelago partially blocks the flow of the Canary Current and this wide and slow moving current is thought to have been exploited in the early Phoenician navigation and settlement along the coast of western Morocco. A prominent feature of Eastern Boundary Currents is the presence of upwelling, ekman drift causes offshore transport of surface waters, which are then replaced with deep water from below. Deep waters are cold and nutrient-rich and have a key role in stimulating primary productivity, upwelling has led to the enhancement of coastal fisheries in western Morocco. Major upwelling occurs between 23 and 25 degrees northern latitude, upwelling occurs year-round at Cap Blanc and northward. South of Cap Blanc, upwelling is limited to winter and spring due to the migration of the Azores high during summer. Minas et al. showed that at the latitude of Cap Blanc, SACW, to the south of Cap Blanc, is richer in nutrients than NACW. A poleward subsurface counter-current is responsible for bringing SACW to the Cap Blanc region resulting in maximal primary production, primary production to the north is limited by nutrient availability in NACW. Primary production to the south of Cap Blanc is limited by the occurrence of upwelling events, Huntsman and Barber hypothesized that high productivity results from alternating upwelling events and relatively calm periods. Upwelling is necessary to bring the nutrients to the surface but if the event is sustained for a period of time. Calm periods allow for stratification to develop, which means that phytoplankton can grow, in other words, there is a miniature spring bloom during each calm period. Upwelling and primary production follow the onset of a wind within a few days. Zooplankton, such as copepods, take longer to respond to the abundance of food available because they have life cycles of weeks rather than days, zooplankton in the Canary Current reach their peak density in autumn when upwelling intensity decreases. The decrease in upwelling allows the zooplankton to stay over the shelf where their food supply exists, due to the rapid response of phytoplankton to upwelled nutrients, zooplankton are seldom food-limited. Four types of fish comprise 75% of total catch in the Cap Blanc region, S. pilchards dominate in the cooler northern waters while S. aurita are prevalent in warmer southern waters. Next most abundant were Jack mackerel and Redfish, Ansa-Emmin found that in 1974, the total fish landings reached 2.68 million tons. Nearly 1 million tons were Clupeidae with.67 million tons being sardines, phytoplankton over the shelf area face two fates, They sink to the bottom or are consumed by zooplankton
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Maghreb
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The Maghreb, or the Greater Maghreb, is usually defined as much or most of the region of western North Africa or Northwest Africa, west of Egypt. Historical terms for the region or various portions of the Maghreb include Mauretania, Numidia, Libya, the term maghrib is Arabic for west, from the verb gharaba. In the strict sense, the definite form al-maghrib denotes the country of Morocco in particular and it identified the westernmost territories that fell to the Islamic conquests of the 7th century. Today, it is a noun for the present region of the Maghreb. The Berber languages alternative term for the region, Tamazgha, has been popularized by Berber activists since the second half of the 20th century. As recently as the late 19th century it was used to refer to the Western Mediterranean region of coastal North Africa in general, and to Algeria, Morocco and Tunisia in particular. The region was unified as an independent political entity during the rule of the Berber kingdom of Numidia. The most enduring rule was that of the local Berber empires of the Almoravids, Almohads, Hammadids, Zirids, Marinids, Saadi, the Ottoman Turks ruled the region as well. Mauritania, Morocco, Tunisia, Algeria, and Libya established the Maghreb Union in 1989 to promote cooperation and it was envisioned initially by Muammar Gaddafi as a superstate. The union included Western Sahara implicitly under Moroccos membership, putting Moroccos long cold war with Algeria to a rest, however, this progress was short-lived, and the union is now frozen. Tensions between Algeria and Morocco over Western Sahara re-emerged strongly, reinforced by the unsolved borderline issue between the two countries and these two main conflicts have hindered progress on the unions joint goals and practically made it inactive as a whole. Around 3,500 BC a tilt in the Earths orbit created a rapid desertification of the Sahara, the Maghreb or western North Africa is believed to have been inhabited by Berbers since from at least 10,000 BC. Maghreb coast ports were predominantly occupied or constructed by the Phoenicians, the main Phoenician settlements centered in the Gulf of Tunis along the North African littoral between the Pillars of Hercules and the Libyan coast east of ancient Cyrenaica. They dominated the trade and intercourse of the Western Mediterranean for centuries, Rome was greatly helped by the defection of King Massinissa and Carthaginians eastern Numidian Massylii client-allies. A century later, the Byzantine emperor Justinian I sent a force under General Belisarius that succeeded in destroying the Vandal kingdom, the Berbers contested outside-the-area control although after the 640s-700 AD period the Arabs controlled the entire region. The Arabs reached the Maghreb in early Umayyad times, Arab expansion and the spread of Islam pushed the development of trans-Saharan trade. While restricted due to the cost and dangers, the trade was highly profitable, commodities traded included such goods as salt, gold, ivory, and slaves. Arab control over the Maghreb was quite weak, various Islamic variations, such as the Ibadis and the Shia, were adopted by some Berbers, often leading to scorning of Caliphal control in favour of their own interpretation of Islam
28.
Benguela Current
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The Benguela Current /bɛŋˈɡweɪlə/ is the broad, northward flowing ocean current that forms the eastern portion of the South Atlantic Ocean gyre. The current extends from roughly Cape Point in the south, to the position of the Angola-Benguela front in the north, the current is driven by the prevailing south easterly trade winds. Inshore of the Benguela Current proper, the easterly winds drive coastal upwelling, forming the Benguela Upwelling System. The cold, nutrient rich waters that upwell from around 200–300 m depth in turn fuel high rates of phytoplankton growth, and sustain the productive Benguela ecosystem. Eddies from the warm South Indian Ocean Agulhas current along South Africas east coast do round the Cape of Good Hope from time to time to join the Bengulela current, the Benguela current is 200 to 300 km wide and widens further as it flows north and northwest. Its western, seaward edge is ill-defined, with temporary and seasonal eddies. Northward winds along the coast result in Ekman transport offshore and upwelling of nutrient rich water to the euphotic zone. The intensity of the event is determined by wind strength. Variations in wind strength cause pulses of upwelling, which propagate to the south along the coast with speeds of 5 to 8 m/s. The pulses are similar to a Kelvin wave, except on a scale of 30 to 60 km instead of 1000 km, pulses of upwelling induce biological production. In the Benguela system, phytoplankton growth requires a period of upwelling followed by a period of stratification, the phytoplankton bloom usually lags the upwelling event by 1 to 4 days and blooms for 4 to 10 days. In order for zooplankton to have a food supply, the phytoplankton blooms must not occur too far apart. Pulses of upwelling in the Benguela system regularly have a duration of 10 days, an optimal period for biological production. It is estimated that the new production in the Benguela system is 4.7 × 10^13 gC/y. The Benguela oxygen minimum zone starts around a depth of 100 m and is a few hundred meters thick, bacteria that use sulpher rather than oxygen reside in the oxygen minimum zone. The most abundant fishes in the Benguela system are Sardinops and Engraulis, Sardinops ocelata was intensely fished beginning in the 1950s and peaking in 1968 with landings over 1.3 million tons. Since then, the Sardinops fishery has declined and the Engraulis capensis fishery has taken over, similar to the Pacific El Niño, a thick slab of warm, nutrient poor water enters the northern part of the Benguela upwelling system off the Namibia coast about once per decade. During the Benguela Niño, warm, salty waters from the Angola Current move southward and this slab of warm salty water extends to 150 km offshore and to 50 m depth
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Southern Africa
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Southern Africa is the southernmost region of the African continent, variably defined by geography or geopolitics, and including several countries. The term southern Africa or Southern Africa, generally includes Angola, Botswana, Lesotho, Malawi, Mozambique, Namibia, South Africa, Swaziland, Zambia, from a political perspective the region is said to be unipolar with South Africa as a first regional power. It is not used in political, economic or human geography contexts because this definition cuts Mozambique in two, the Southern African Development Community was established in 1980 to facilitate co-operation in the region. Comoros, Madagascar, Malawi, Mayotte, Mauritius, Mozambique, Réunion, Seychelles, Zambia, the Democratic Republic of the Congo and Tanzania, though more commonly reckoned in Central and Eastern Africa, respectively, are occasionally included in Southern Africa as they are SADC members. The terrain of Southern Africa is varied, ranging from forest, the region has both low-lying coastal areas, and mountains. While colonialism has left its mark on the development over the course of history, today poverty, corruption, the pursuit of economic and political stability is an important part of the regions goals, as demonstrated by the SADC. In terms of strength, South Africa is by far the dominant power of the region. South Africas GDP alone is many times greater than the GDPs of all countries in the region. Southern Africa has a diversity of ecoregions including grassland, bushveld, karoo, savannah. It has complex Plateaus that create massive mountain structures along the South African border, there are numerous environmental issues in Southern Africa, including air pollution and desertification. Southern Africa is home to cultures and people. It was once populated by San, Khoikhoi and Pygmies in widely dispersed concentrations, the process of colonization and settling resulted in a significant population of European and Asian descent in many southern African countries. These factors vary from country to country, for example, the Democratic Republic of Congo has favourable climatic and physical conditions, but performs far below its capacity in food provision due to political instability and poor governance. The Republic of South Africa is a food producer and exporter in the region. However this data might not fully capture the reality of a region with high urban populations, urban food security has been noted as an emerging area of development concern in the region, with recent data showing high levels of food insecurity amongst low-income households. In South Africa for example, while over 50% experience hunger, there is only limited data on the other Southern African countries. History of Southern Africa Sub-Saharan Africa Southern Africa
30.
California Current
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It is considered an Eastern boundary current due to the influence of the North American coastline on its course. It is also one of five major coastal currents affiliated with upwelling zones, the others being the Humboldt Current, the Canary Current, the Benguela Current, and the Somali Current. The California Current is part of the North Pacific Gyre, a large swirling current that occupies the northern basin of the Pacific. For example, Half Moon Bay at 37 degrees latitude has no month with a high above 67 °F. Additionally, extensive upwelling of colder sub-surface waters occurs, caused by the northwesterly winds acting through the Ekman Effect. The winds drive surface water to the right of the flow, that is offshore. The upwelling further cools the already cool California Current and this is the mechanism that produces Californias characteristic coastal fog and the negative temperature anomaly measured in Californias coastal waters during summer. This translates into cold coastal waters during the summer, stretching from Oregon to Baja California and this does not include the coastal water surrounding San Diego, where a warm water anomaly occurs. The cold water is highly due to the upwelling, which brings to the surface nutrient-rich sediments, supporting large populations of whales, seabirds. Winds of the direction and strength to induce upwelling are more prevalent in the presence of Eastern boundary currents. Phytoplankton production is increased in these areas because the nutrient-rich water lying below the pycnocline is relatively close to the surface and is thus easily upwelled. Scientists at Scripps Institution of Oceanography said in 2011 that the surface temperature of the water at Scripps Pier has increased by almost 3 degrees since 1950. The Bakun upwelling index is based on a 20-year average of the monthly mean Ekman transport for different regions off the California coast and it ranges from 300 meters-cubed/second to −212 meters-cubed/second. There is year-round upwelling off Southern Californias coast, but it is strongest in the summer months, off the coast of Oregon and Washington, there is forceful downwelling in the winter months, and upwelling in the region is restricted to the months of April through September. Primary production is a topic of interest among those who study the California Current, in their study, Hayward and Venrick found great variability in both biomass and the productivity of phytoplankton in the California Current. The differences observed by Hayward and Venrick in carbon-fixation rates show the nature of the California Current. Several studies have investigated the carbon flow from primary production to the fish stocks which depend on the California Current. Lasker described powerful jets and squirts off northern and central California and these jets and squirts move large quantities of cold, nutrient rich water offshore
31.
California
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California is the most populous state in the United States and the third most extensive by area. Located on the western coast of the U. S, California is bordered by the other U. S. states of Oregon, Nevada, and Arizona and shares an international border with the Mexican state of Baja California. Los Angeles is Californias most populous city, and the second largest after New York City. The Los Angeles Area and the San Francisco Bay Area are the nations second- and fifth-most populous urban regions, California also has the nations most populous county, Los Angeles County, and its largest county by area, San Bernardino County. The Central Valley, an agricultural area, dominates the states center. What is now California was first settled by various Native American tribes before being explored by a number of European expeditions during the 16th and 17th centuries, the Spanish Empire then claimed it as part of Alta California in their New Spain colony. The area became a part of Mexico in 1821 following its war for independence. The western portion of Alta California then was organized as the State of California, the California Gold Rush starting in 1848 led to dramatic social and demographic changes, with large-scale emigration from the east and abroad with an accompanying economic boom. If it were a country, California would be the 6th largest economy in the world, fifty-eight percent of the states economy is centered on finance, government, real estate services, technology, and professional, scientific and technical business services. Although it accounts for only 1.5 percent of the states economy, the story of Calafia is recorded in a 1510 work The Adventures of Esplandián, written as a sequel to Amadis de Gaula by Spanish adventure writer Garci Rodríguez de Montalvo. The kingdom of Queen Calafia, according to Montalvo, was said to be a land inhabited by griffins and other strange beasts. This conventional wisdom that California was an island, with maps drawn to reflect this belief, shortened forms of the states name include CA, Cal. Calif. and US-CA. Settled by successive waves of arrivals during the last 10,000 years, various estimates of the native population range from 100,000 to 300,000. The Indigenous peoples of California included more than 70 distinct groups of Native Americans, ranging from large, settled populations living on the coast to groups in the interior. California groups also were diverse in their organization with bands, tribes, villages. Trade, intermarriage and military alliances fostered many social and economic relationships among the diverse groups, the first European effort to explore the coast as far north as the Russian River was a Spanish sailing expedition, led by Portuguese captain Juan Rodríguez Cabrillo, in 1542. Some 37 years later English explorer Francis Drake also explored and claimed a portion of the California coast in 1579. Spanish traders made unintended visits with the Manila galleons on their trips from the Philippines beginning in 1565
32.
Oregon
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Oregon is a state in the Pacific Northwest region of the United States. Oregon is bordered on the west by the Pacific Ocean, on the north by Washington, on the south by California, on the east by Idaho, the Columbia River delineates much of Oregons northern boundary, and the Snake River delineates much of the eastern boundary. The parallel 42° north delineates the boundary with California and Nevada. Oregon was inhabited by indigenous tribes before Western traders, explorers. An autonomous government was formed in the Oregon Country in 1843 before the Oregon Territory was created in 1848, Oregon became the 33rd state on February 14,1859. Today, at 98,000 square miles, Oregon is the ninth largest and, with a population of 4 million, the capital of Oregon is Salem, the second most populous of its cities, with 164,549 residents. Portland is Oregons most populous city, with 632,309 residents, Portlands metro population of 2,389,228 ranks the 23rd largest metro in the nation. The Willamette Valley in western Oregon is the states most densely populated area, the tall conifers, mainly Douglas fir, along Oregons rainy west coast contrast with the lighter-timbered and fire-prone pine and juniper forests covering portions to the east. Abundant alders in the west fix nitrogen for the conifers, stretching east from central Oregon are semi-arid shrublands, prairies, deserts, steppes, and meadows. At 11,249 feet, Mount Hood is the states highest point, Oregons only national park, Crater Lake National Park, comprises the caldera surrounding Crater Lake, the deepest lake in the United States. The state is home to the single largest organism in the world, Armillaria ostoyae. Because of its landscapes and waterways, Oregons economy is largely powered by various forms of agriculture, fishing. It is also the top timber-producer of the lower 48 states, Technology is another one of the states major economic forces, which began in the 1970s with the establishment of the Silicon Forest and the expansion of Tektronix and Intel. Sportswear company Nike, Inc. headquartered in Beaverton, is the states largest public corporation with a revenue of $30.6 billion. The earliest evidence of the name Oregon has Spanish origins and this chronicle is the first topographical and linguistic source with respect to the place name Oregon. There are also two other sources with Spanish origins such as the name Oregano which grows in the part of the region. Another early use of the name, spelled Ouragon, was in a 1765 petition by Major Robert Rogers to the Kingdom of Great Britain, the term referred to the then-mythical River of the West. By 1778 the spelling had shifted to Oregon, in his 1765 petition, Rogers wrote, The rout. is from the Great Lakes towards the Head of the Mississippi, and from thence to the River called by the Indians Ouragon
33.
Humboldt Current
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The Humboldt Current is a cold, low-salinity ocean current that flows north along the west coast of South America from the southern tip of Chile to northern Peru. Also called the Peru Current, it is an eastern boundary current flowing in the direction of the equator and it is the most productive marine ecosystem in the world, as well as the largest upwelling system. The Humboldt’s high rates of primary and secondary productivity support the world’s largest fisheries, approximately 18-20% of the world’s fish catch comes from the Humboldt Current LME. The species are pelagic, sardines, anchovies and jack mackerel. The LME’s high productivity supports other important fishery resources as well as marine mammals, the cold, nutrient-rich water brought to the surface by upwelling drives the system’s extraordinary productivity. Periodically, the upwelling that drives the system’s productivity is disrupted by the El Niño-Southern Oscillation event, when this occurs, fish abundance and distribution are significantly affected, often leading to stock crashes and cascading social and economic impacts. These events have led to changes, where sardines and anchovies have replaced each other periodically as the dominant species in the ecosystem. These species changes can have consequences for the fishing industry. The Humboldt has a cooling influence on the climate of Chile, Peru. It is also responsible for the aridity of Atacama Desert in northern Chile and coastal areas of Peru. Marine air is cooled by the current and thus is not conducive to generating precipitation
34.
Peru
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Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the west by the Pacific Ocean. Peruvian territory was home to ancient cultures spanning from the Norte Chico civilization in Caral, one of the oldest in the world, to the Inca Empire, the largest state in Pre-Columbian America. The Spanish Empire conquered the region in the 16th century and established a Viceroyalty with its capital in Lima, ideas of political autonomy later spread throughout Spanish America and Peru gained its independence, which was formally proclaimed in 1821. After the battle of Ayacucho, three years after proclamation, Peru ensured its independence, subsequently, the country has undergone changes in government from oligarchic to democratic systems. Peru has gone through periods of political unrest and internal conflict as well as periods of stability, Peru is a representative democratic republic divided into 25 regions. It is a country with a high Human Development Index score. Its main economic activities include mining, manufacturing, agriculture and fishing, the Peruvian population, estimated at 31.2 million in 2015, is multiethnic, including Amerindians, Europeans, Africans and Asians. The main spoken language is Spanish, although a significant number of Peruvians speak Quechua or other native languages and this mixture of cultural traditions has resulted in a wide diversity of expressions in fields such as art, cuisine, literature, and music. The name of the country may be derived from Birú, the name of a ruler who lived near the Bay of San Miguel, Panama. When his possessions were visited by Spanish explorers in 1522, they were the southernmost part of the New World yet known to Europeans, thus, when Francisco Pizarro explored the regions farther south, they came to be designated Birú or Perú. An alternative history is provided by the contemporary writer Inca Garcilasco de la Vega, son of an Inca princess, the Spanish Crown gave the name legal status with the 1529 Capitulación de Toledo, which designated the newly encountered Inca Empire as the province of Peru. Under Spanish rule, the country adopted the denomination Viceroyalty of Peru, the earliest evidences of human presence in Peruvian territory have been dated to approximately 9,000 BC. Andean societies were based on agriculture, using such as irrigation and terracing, camelid husbandry. Organization relied on reciprocity and redistribution because these societies had no notion of market or money, the oldest known complex society in Peru, the Norte Chico civilization, flourished along the coast of the Pacific Ocean between 3,000 and 1,800 BC. These early developments were followed by archaeological cultures that developed mostly around the coastal, the Cupisnique culture which flourished from around 1000 to 200 BC along what is now Perus Pacific Coast was an example of early pre-Incan culture. The Chavín culture that developed from 1500 to 300 BC was probably more of a religious than a political phenomenon, on the coast, these included the civilizations of the Paracas, Nazca, Wari, and the more outstanding Chimu and Mochica. Their capital was at Chan Chan outside of modern-day Trujillo, in the 15th century, the Incas emerged as a powerful state which, in the span of a century, formed the largest empire in pre-Columbian America with their capital in Cusco
35.
Chile
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Chile, officially the Republic of Chile, is a South American country occupying a long, narrow strip of land between the Andes to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, Chilean territory includes the Pacific islands of Juan Fernández, Salas y Gómez, Desventuradas, and Easter Island in Oceania. Chile also claims about 1,250,000 square kilometres of Antarctica, the arid Atacama Desert in northern Chile contains great mineral wealth, principally copper. Southern Chile is rich in forests and grazing lands, and features a string of volcanoes and lakes, the southern coast is a labyrinth of fjords, inlets, canals, twisting peninsulas, and islands. Spain conquered and colonized Chile in the century, replacing Inca rule in northern and central Chile. After declaring its independence from Spain in 1818, Chile emerged in the 1830s as a relatively stable authoritarian republic, in the 1960s and 1970s the country experienced severe left-right political polarization and turmoil. The regime, headed by Augusto Pinochet, ended in 1990 after it lost a referendum in 1988 and was succeeded by a coalition which ruled through four presidencies until 2010. Chile is today one of South Americas most stable and prosperous nations and it leads Latin American nations in rankings of human development, competitiveness, income per capita, globalization, state of peace, economic freedom, and low perception of corruption. It also ranks high regionally in sustainability of the state, Chile is a founding member of the United Nations, the Union of South American Nations and the Community of Latin American and Caribbean States. There are various theories about the origin of the word Chile, another theory points to the similarity of the valley of the Aconcagua with that of the Casma Valley in Peru, where there was a town and valley named Chili. Another origin attributed to chilli is the onomatopoeic cheele-cheele—the Mapuche imitation of the warble of a locally known as trile. The Spanish conquistadors heard about this name from the Incas, ultimately, Almagro is credited with the universalization of the name Chile, after naming the Mapocho valley as such. The older spelling Chili was in use in English until at least 1900 before switching over to Chile, stone tool evidence indicates humans sporadically frequented the Monte Verde valley area as long as 18,500 years ago. About 10,000 years ago, migrating Native Americans settled in fertile valleys, settlement sites from very early human habitation include Monte Verde, Cueva del Milodon and the Pali Aike Craters lava tube. They fought against the Sapa Inca Tupac Yupanqui and his army, the result of the bloody three-day confrontation known as the Battle of the Maule was that the Inca conquest of the territories of Chile ended at the Maule river. The next Europeans to reach Chile were Diego de Almagro and his band of Spanish conquistadors, the Spanish encountered various cultures that supported themselves principally through slash-and-burn agriculture and hunting. The conquest of Chile began in earnest in 1540 and was carried out by Pedro de Valdivia, one of Francisco Pizarros lieutenants, who founded the city of Santiago on 12 February 1541. Although the Spanish did not find the gold and silver they sought, they recognized the agricultural potential of Chiles central valley
36.
Somali Current
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The Somali Current is an ocean boundary current that runs along the coast of Somalia and Oman in the Western Indian Ocean and is analogous to the Gulf Stream in the Atlantic Ocean. This current is heavily influenced by the monsoons and is the major upwelling system that occurs on a western boundary of an ocean. The water that is upwelled by the current merges with another upwelling system, the Somali current is characterized by seasonal changes influenced by the Southwest monsoon and the Northeast Monsoon. During the months of June to September, the warm Southwest monsoon moves the coastal waters northeastward, the upwelled water is carried offshore by Ekman transport and merges with water that was brought to the surface by open-ocean upwelling. The Findlater jet, a narrow low-level, atmospheric jet, also develops during the Southwest monsoon, as a result, an Ekman transport is created to the right of the wind. At the center of the jet, the transport is maximum and decreases to the right, to the left of the jet center, there is less water movement toward the center than is leaving, creating a divergence in the upper layer and resulting in an upwelling event. In contrast, to the right of the center of the jet and this open-ocean upwelling in combination with the coastal upwelling cause a massive upwelling. The Northeast monsoon, which occurs from December to February, causes a reversal of the Somalia current, cooler air causes the surface water to cool and creates deep mixing, bringing abundant nutrients to the surface. The history of physical oceanographic approaches to the Somali current has begun from the mid 1960s with serious interests, from the mid-1960s until the late 1970s several magnificent theoretical studies had been proposed and gave physical answers of the current behaviors and formations. After the late 1970s, the physics of the Somali current enhanced by ocean data analyses with outstanding field measurements of the current properties, the research footprints during the early 1960s to the late 1970s are presented as below. Oceanographers and Meteorologists agreed the existence of the Somali current and its behaviors,1969 Lighthill, the source of the Somali current is mass flux deposited by baroclinic and barotropic waves in the western boundary region. 1970 Düing, presented the presence of alternative cyclonic and anti-cyclonic gyre, the Somali Current is rapid response, shallow and shifts its direction seasonally. Especially from 5°N and southward, the Somali current is extremely shallow, further north, the jet deepens somewhat, reaching the permanent thermocline. The structure of the current around the equator is extremely complex and similarly layered to the equatorial flows, the typical water volume transported by the Somali Current amounts to 37+/-5 Sv, making the current circulation generally weaker than other mid-latitude western boundary currents. However, volume transport maxima as high as 60-70 Sv have been measured around the south of Socotra Island, the Somali Current is driven principally by the seasonal monsoon winds. In summer the southwest monsoon blows along the east coast of Africa, during the fall it reverses its direction to become a northeasterly wind during winter. Before the onset of the monsoon, During this season, shallow northward coastal current flows with 50–100 km width near the Somali coast, by alongshore winds, upwelling current flows to the coast. Near the equator, the East African Coast Current flows northward across the equator, the southern Somali Current flows northward as an extension of the EACC from south to the 3-4°N
37.
Somalia
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Somalia, officially the Federal Republic of Somalia, is a country located in the Horn of Africa. It is bordered by Ethiopia to the west, Djibouti to the northwest, the Gulf of Aden to the north, the Indian Ocean to the east, Somalia has the longest coastline on Africas mainland, and its terrain consists mainly of plateaus, plains and highlands. Climatically, hot conditions prevail year-round, with monsoon winds. Somalia has an population of around 12.3 million. Around 85% of its residents are ethnic Somalis, who have inhabited the northern part of the country. Ethnic minorities are largely concentrated in the southern regions, the official languages of Somalia are Somali and Arabic, both of which belong to the Afroasiatic family. Most people in the country are Muslim, with the majority being Sunni, in antiquity, Somalia was an important commercial centre. It is among the most probable locations of the fabled ancient Land of Punt, during the Middle Ages, several powerful Somali empires dominated the regional trade, including the Ajuran Empire, the Adal Sultanate, the Warsangali Sultanate, and the Geledi Sultanate. The toponym Somalia was coined by the Italian explorer Luigi Robecchi Bricchetti, Italian occupation lasted until 1941, yielding to British military administration. British Somaliland would remain a protectorate, while Italian Somaliland in 1949 became a United Nations Trusteeship under Italian administration, in 1960, the two regions united to form the independent Somali Republic under a civilian government. The Supreme Revolutionary Council seized power in 1969 and established the Somali Democratic Republic, led by Mohamed Siad Barre, this government later collapsed in 1991 as the Somali Civil War broke out. Various armed factions began competing for influence in the power vacuum, during this period, due to the absence of a central government, Somalia was a failed state, and residents returned to customary and religious law in most regions. A few autonomous regions, including the Somaliland and Puntland administrations emerged in the north, the early 2000s saw the creation of fledgling interim federal administrations. The Transitional National Government was established in 2000, followed by the formation of the Transitional Federal Government in 2004, in 2006, the TFG, assisted by Ethiopian troops, assumed control of most of the nations southern conflict zones from the newly formed Islamic Courts Union. The ICU subsequently splintered into more radical groups such as Al-Shabaab, by mid-2012, the insurgents had lost most of the territory that they had seized. In 2011–2012, a political process providing benchmarks for the establishment of permanent democratic institutions was launched, within this administrative framework a new provisional constitution was passed in August 2012, which reformed Somalia as a federation. Somalia has maintained an informal economy, mainly based on livestock, remittances from Somalis working abroad, Somalia has been inhabited since at least the Paleolithic. During the Stone Age, the Doian and Hargeisan cultures flourished here, the oldest evidence of burial customs in the Horn of Africa comes from cemeteries in Somalia dating back to the 4th millennium BCE
38.
Oman
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Oman, officially the Sultanate of Oman, is an Arab country on the southeastern coast of the Arabian Peninsula. The coast is formed by the Arabian Sea on the southeast, the Madha and Musandam exclaves are surrounded by the UAE on their land borders, with the Strait of Hormuz and Gulf of Oman forming Musandams coastal boundaries. From the late 17th century, the Omani Sultanate was an empire, vying with Portugal and Britain for influence in the Persian Gulf. At its peak in the 19th century, Omani influence or control extended across the Strait of Hormuz to modern-day Iran and Pakistan, as its power declined in the 20th century, the sultanate came under the influence of the United Kingdom. Historically, Muscat was the trading port of the Persian Gulf region. Muscat was also among the most important trading ports of the Indian Ocean, the Sultan Qaboos bin Said al Said has been the hereditary leader of the country since 1970. Sultan Qaboos is the current ruler in the Middle East. Oman has modest oil reserves, ranking 25th globally, nevertheless, in 2010 the UNDP ranked Oman as the most improved nation in the world in terms of development during the preceding 40 years. A significant portion of its economy is tourism and trade of fish, dates and this sets it apart from its neighbors solely oil-dependent economies. Oman is categorized as an economy and ranks as the 74th most peaceful country in the world according to the Global Peace Index. Two optically stimulated luminescence age estimates place the Arabian Nubian Complex at 106,000 years old and this supports the proposition that early human populations moved from Africa into Arabia during the Late Pleistocene. Dereaze, located in the city of Ibri, is the oldest known settlement in the area. Archaeological remains have been discovered here from the Stone Age and the Bronze Age, findings have included stone implements, animal bones, shells and fire hearths, with the latter dating back to 7615 BC as the oldest signs of human settlement in the area. Other discoveries include hand-molded pottery bearing distinguishing pre-Bronze Age marks, heavy flint implements, pointed tools, sumerian tablets refer to a country called Magan or Makan, a name believed to refer to Omans ancient copper mines. Mazoon, another used for the region, is derived from the word muzn. The present-day name of the country, Oman, is believed to originate from the Arab tribes who migrated to its territory from the Uman region of Yemen. Many such tribes settled in Oman, making a living by fishing, herding or stock breeding, from the 6th century BC to the arrival of Islam in the 7th century AD, Oman was controlled and/or influenced by three Persian dynasties, the Achaemenids, Parthians and Sassanids. A few scholars believe that in the 6th century BC, the Achaemenids exerted a strong degree of control over the Omani peninsula, Central Oman has its own indigenous so-called Late Iron Age cultural assemblage, the Samad al-Shan
39.
South Atlantic Gyre
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The South Atlantic Gyre is the subtropical gyre in the south Atlantic Ocean. In the southern portion of the gyre, northwesterly winds drive eastward-flowing currents that are difficult to distinguish from the boundary of the Antarctic Circumpolar Current. Like other oceanic gyres, it collects vast amounts of floating debris, South of this gyre is the Antarctic Circumpolar Current. This current flows from West to East around Antarctica, another name for this current is the West Wind Drift. This current allows Antarctica to maintain its huge ice sheet by keeping warm ocean waters away, at approximately 125 Sv, this current is the largest ocean current. The Brazil Current is the western boundary current of the gyre and it flows south along the Brazilian coast to the Rio de la Plata. The current is considerably weaker than its North Atlantic counterpart, the Gulf Stream, Ocean current Volta do mar Ocean currents Ocean currents
40.
Point Conception
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Point Conception is a headland along the Pacific coast of the U. S. state of California, located in southwestern Santa Barbara County. The Point Conception Lighthouse is at its tip, Point Conception was first noted by Spanish maritime explorer Juan Rodriguez Cabrillo in 1542 and named Cabo de Galera. In 1602, Sebastian Vizcaíno sailed past again, renaming the protruding headland Punta de la Limpia Concepción, vizcaínos name stuck, and was later anglicized to todays version. It is called Humqaq in the Chumashan languages, in 1978, the Point Conception area was occupied by Chumash and other Native Americans trying to save it from development by a liquefied natural gas company. Courtney Milne, Sacred Places in North America, A Journey into the Medicine Wheel
41.
North Atlantic Gyre
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The North Atlantic Gyre, located in the Atlantic Ocean, is one of the five major oceanic gyres. This gyre is similar to the North Pacific Gyre in the way it traps man-made marine debris in the North Atlantic Garbage Patch, the North Atlantic Gyre forms the Sargasso Sea, noted for its still waters and dense seaweed accumulations. As with many patterns, the North Atlantic Gyre experiences seasonal changes. Stramma and Siedler determined that the gyre expands and contracts with a variance, however. During the Northern Hemisphere winter season, the gyre follows a more zonal pattern, as the seasons move from winter to summer, the gyre shifts south by a few degrees latitude. This occurs concurrently with the displacement of the part of the gyre. It has been concluded that zonal deviations within the gyre remain small while north and south of the gyre they are large. Data collected in the Sargasso Sea region in the part of the North Atlantic Gyre has led to analytical evidence that the variability of this gyre is linked to wintertime convective mixing. According to Bates, a variation of 8-10 °C in surface temperature occurs alongside a fluctuation in the mixed layer depth between the Northern Hemisphere winter and summer seasons. The depth rises from 200 meters in winter to about 10 meters in summer, nutrients remain below the euphotic zone for most of the year, resulting in low primary production. Yet during winter convective mixing, nutrients penetrate the euphotic zone and this then lifts the mixed-layer depth to 10 meters. The changes in oceanic biology and vertical mixing between winter and summer in the North Atlantic Gyre seasonally alter the amount of carbon dioxide in the seawater. Interannual trends have established that carbon dioxide concentrations within this gyre are increasing at a rate to that occurring in the atmosphere. This discovery concurs with that made in the North Pacific Gyre, the North Atlantic Gyre also undergoes temperature changes via atmospheric wave patterns. The North Atlantic Oscillation is one such pattern, during its positive phase, the gyre warms. This is due to a weakening of the winds, resulting in reduced wind stress and heat exchange. Collections of aerosols, marine particles, and ocean water in the North Atlantic Gyre from 1990-1992 have led to measurements in lead isotope ratios, the surface layers of the Sargasso Sea were used to estimate the lead isotopic concentrations. 42-57% of the lead isotope concentrations result from American industrial and automotive contamination, despite the reduction in the production, however, lead concentrations from measurements made after 1992 show a decrease in the amount of lead contamination
42.
Canary Islands
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The Canary Islands, also known as the Canaries, are an archipelago and autonomous community of Spain located on the Atlantic Ocean,100 kilometres west of Morocco. The Canaries are among the outermost regions of the European Union proper and it is also one of the eight regions with special consideration of historical nationality recognized as such by the Spanish Government. The main islands are Tenerife, Fuerteventura, Gran Canaria, Lanzarote, La Palma, La Gomera, the archipelago also includes a number of islands and islets, La Graciosa, Alegranza, Isla de Lobos, Montaña Clara, Roque del Oeste and Roque del Este. In ancient times, the chain was often referred to as the Fortunate Isles. The Canary Islands is the most southerly region of Spain and the largest and most populated archipelago of the Macaronesia region, the islands have a subtropical climate, with long hot summers and moderately warm winters. The precipitation levels and the level of maritime moderation varies depending on location and elevation, green areas as well as desert exist on the archipelago. Due to their location above the inversion layer, the high mountains of these islands are ideal for astronomical observation. For this reason, two professional observatories, Teide Observatory on the island of Tenerife and Roque de los Muchachos Observatory on the island of La Palma, have built on the islands. Las Palmas de Gran Canaria has been the largest city in the Canaries since 1768, between the 1833 territorial division of Spain and 1927 Santa Cruz de Tenerife was the sole capital of the Canary Islands. In 1927 a decree ordered that the capital of the Canary Islands be shared, the third largest city of the Canary Islands is San Cristóbal de La Laguna on Tenerife. This city is home to the Consejo Consultivo de Canarias. During the time of the Spanish Empire, the Canaries were the main stopover for Spanish galleons on their way to the Americas, who came south to catch the prevailing northeasterly trade winds. The name Islas Canarias is likely derived from the Latin name Canariae Insulae, meaning Islands of the Dogs, according to the historian Pliny the Elder, the Mauretanian king Juba II named the island Canaria because it contained vast multitudes of dogs of very large size. Another speculation is that the dogs were actually a species of monk seal, critically endangered. The dense population of seals may have been the characteristic that most struck the few ancient Romans who established contact with these islands by sea. Alternatively, it is said that the inhabitants of the island, Guanches, used to worship dogs, mummified them. The ancient Greeks also knew about a people, living far to the west, who are the dog-headed ones, who worshipped dogs on an island. Some hypothesize that the Canary Islands dog-worship and the ancient Egyptian cult of the god, Anubis are closely connected
43.
South America
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South America is a continent located in the western hemisphere, mostly in the southern hemisphere, with a relatively small portion in the northern hemisphere. It may also be considered a subcontinent of the Americas, which is the used in nations that speak Romance languages. The reference to South America instead of other regions has increased in the last decades due to changing geopolitical dynamics. It is bordered on the west by the Pacific Ocean and on the north and east by the Atlantic Ocean, North America and it includes twelve sovereign states, a part of France, and a non-sovereign area. In addition to this, the ABC islands of the Kingdom of the Netherlands, Trinidad and Tobago, South America has an area of 17,840,000 square kilometers. Its population as of 2005 has been estimated at more than 371,090,000, South America ranks fourth in area and fifth in population. Brazil is by far the most populous South American country, with more than half of the population, followed by Colombia, Argentina, Venezuela. In recent decades Brazil has also concentrated half of the regions GDP and has become a first regional power, most of the population lives near the continents western or eastern coasts while the interior and the far south are sparsely populated. Most of the continent lies in the tropics, the continents cultural and ethnic outlook has its origin with the interaction of indigenous peoples with European conquerors and immigrants and, more locally, with African slaves. Given a long history of colonialism, the majority of South Americans speak Portuguese or Spanish. South America occupies the portion of the Americas. The continent is delimited on the northwest by the Darién watershed along the Colombia–Panama border. Almost all of mainland South America sits on the South American Plate, South Americas major mineral resources are gold, silver, copper, iron ore, tin, and petroleum. These resources found in South America have brought high income to its countries especially in times of war or of rapid growth by industrialized countries elsewhere. However, the concentration in producing one major export commodity often has hindered the development of diversified economies and this is leading to efforts to diversify production to drive away from staying as economies dedicated to one major export. South America is one of the most biodiverse continents on earth, South America is home to many interesting and unique species of animals including the llama, anaconda, piranha, jaguar, vicuña, and tapir. The Amazon rainforests possess high biodiversity, containing a proportion of the Earths species. Brazil is the largest country in South America, encompassing around half of the land area
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Pacific Ocean
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The Pacific Ocean is the largest and deepest of the Earths oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean in the south and is bounded by Asia and Australia in the west, the Mariana Trench in the western North Pacific is the deepest point in the world, reaching a depth of 10,911 metres. Both the center of the Water Hemisphere and the Western Hemisphere are in the Pacific Ocean, the oceans current name was coined by Portuguese explorer Ferdinand Magellan during the Spanish circumnavigation of the world in 1521, as he encountered favourable winds on reaching the ocean. He called it Mar Pacífico, which in both Portuguese and Spanish means peaceful sea, important human migrations occurred in the Pacific in prehistoric times. Long-distance trade developed all along the coast from Mozambique to Japan, trade, and therefore knowledge, extended to the Indonesian islands but apparently not Australia. By at least 878 when there was a significant Islamic settlement in Canton much of trade was controlled by Arabs or Muslims. In 219 BC Xu Fu sailed out into the Pacific searching for the elixir of immortality, from 1404 to 1433 Zheng He led expeditions into the Indian Ocean. The east side of the ocean was discovered by Spanish explorer Vasco Núñez de Balboa in 1513 after his expedition crossed the Isthmus of Panama and he named it Mar del Sur because the ocean was to the south of the coast of the isthmus where he first observed the Pacific. Later, Portuguese explorer Ferdinand Magellan sailed the Pacific East to West on a Castilian expedition of world circumnavigation starting in 1519, Magellan called the ocean Pacífico because, after sailing through the stormy seas off Cape Horn, the expedition found calm waters. The ocean was often called the Sea of Magellan in his honor until the eighteenth century, sailing around and east of the Moluccas, between 1525 and 1527, Portuguese expeditions discovered the Caroline Islands, the Aru Islands, and Papua New Guinea. In 1542–43 the Portuguese also reached Japan, in 1564, five Spanish ships consisting of 379 explorers crossed the ocean from Mexico led by Miguel López de Legazpi and sailed to the Philippines and Mariana Islands. The Manila galleons operated for two and a half centuries linking Manila and Acapulco, in one of the longest trade routes in history, Spanish expeditions also discovered Tuvalu, the Marquesas, the Cook Islands, the Solomon Islands, and the Admiralty Islands in the South Pacific. In the 16th and 17th century Spain considered the Pacific Ocean a Mare clausum—a sea closed to other naval powers, as the only known entrance from the Atlantic the Strait of Magellan was at times patrolled by fleets sent to prevent entrance of non-Spanish ships. On the western end of the Pacific Ocean the Dutch threatened the Spanish Philippines, Spain also sent expeditions to the Pacific Northwest reaching Vancouver Island in southern Canada, and Alaska. The French explored and settled Polynesia, and the British made three voyages with James Cook to the South Pacific and Australia, Hawaii, and the North American Pacific Northwest, one of the earliest voyages of scientific exploration was organized by Spain in the Malaspina Expedition of 1789–1794. It sailed vast areas of the Pacific, from Cape Horn to Alaska, Guam and the Philippines, New Zealand, Australia, and the South Pacific. Growing imperialism during the 19th century resulted in the occupation of much of Oceania by other European powers, and later, Japan, in Oceania, France got a leading position as imperial power after making Tahiti and New Caledonia protectorates in 1842 and 1853 respectively. After navy visits to Easter Island in 1875 and 1887, Chilean navy officer Policarpo Toro managed to negotiate an incorporation of the island into Chile with native Rapanui in 1888, by occupying Easter Island, Chile joined the imperial nations
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Equator
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The Equator usually refers to an imaginary line on the Earths surface equidistant from the North Pole and South Pole, dividing the Earth into the Northern Hemisphere and Southern Hemisphere. The Equator is about 40,075 kilometres long, some 78. 7% lies across water and 21. 3% over land, other planets and astronomical bodies have equators similarly defined. Generally, an equator is the intersection of the surface of a sphere with the plane that is perpendicular to the spheres axis of rotation. The latitude of the Earths equator is by definition 0° of arc, the equator is the only line of latitude which is also a great circle — that is, one whose plane passes through the center of the globe. The plane of Earths equator when projected outwards to the celestial sphere defines the celestial equator, in the cycle of Earths seasons, the plane of the equator passes through the Sun twice per year, at the March and September equinoxes. To an observer on the Earth, the Sun appears to travel North or South over the equator at these times, light rays from the center of the Sun are perpendicular to the surface of the Earth at the point of solar noon on the Equator. Locations on the Equator experience the quickest sunrises and sunsets because the sun moves nearly perpendicular to the horizon for most of the year. The Earth bulges slightly at the Equator, the diameter of the Earth is 12,750 kilometres. Because the Earth spins to the east, spacecraft must also launch to the east to take advantage of this Earth-boost of speed, seasons result from the yearly revolution of the Earth around the Sun and the tilt of the Earths axis relative to the plane of revolution. During the year the northern and southern hemispheres are inclined toward or away from the sun according to Earths position in its orbit, the hemisphere inclined toward the sun receives more sunlight and is in summer, while the other hemisphere receives less sun and is in winter. At the equinoxes, the Earths axis is not tilted toward the sun, instead it is perpendicular to the sun meaning that the day is about 12 hours long, as is the night, across the whole of the Earth. Near the Equator there is distinction between summer, winter, autumn, or spring. The temperatures are usually high year-round—with the exception of high mountains in South America, the temperature at the Equator can plummet during rainstorms. In many tropical regions people identify two seasons, the wet season and the dry season, but many places close to the Equator are on the oceans or rainy throughout the year, the seasons can vary depending on elevation and proximity to an ocean. The Equator lies mostly on the three largest oceans, the Pacific Ocean, the Atlantic Ocean, and the Indian Ocean. The highest point on the Equator is at the elevation of 4,690 metres, at 0°0′0″N 77°59′31″W and this is slightly above the snow line, and is the only place on the Equator where snow lies on the ground. At the Equator the snow line is around 1,000 metres lower than on Mount Everest, the Equator traverses the land of 11 countries, it also passes through two island nations, though without making a landfall in either. Starting at the Prime Meridian and heading eastwards, the Equator passes through, Despite its name, however, its island of Annobón is 155 km south of the Equator, and the rest of the country lies to the north
