Krill are small crustaceans of the order Euphausiacea, and are found in all the worlds oceans. The name krill comes from the Norwegian word krill, meaning small fry of fish, which is often attributed to species of fish. In the Southern Ocean, one species, the Antarctic krill, Euphausia superba, makes up an estimated biomass of around 379,000,000 tonnes, making it among the species with the largest total biomass. Of this, over half is eaten by whales, penguins and fish each year, most krill species display large daily vertical migrations, thus providing food for predators near the surface at night and in deeper waters during the day. Krill are fished commercially in the Southern Ocean and in the waters around Japan, the total global harvest amounts to 150, 000–200,000 tonnes annually, most of this from the Scotia Sea. Most of the catch is used for aquaculture and aquarium feeds, as bait in sport fishing. In Japan and Russia, krill are used for human consumption and are known as okiami in Japan.
They are eaten as camarones in Spain, in the Philippines, it is known as alamang and it is used to make a salty paste called bagoong. Krill are the prey of baleen whales, including the blue whale. Krill belong to the arthropod subphylum, the Crustacea. The most familiar and largest group of crustaceans, the class Malacostraca, the order Euphausiacea comprises two families. The more abundant Euphausiidae contains ten different genera with a total of 85 species, of these, the genus Euphausia is the largest, with 31 species. The lesser known family, the Bentheuphausiidae, has one species, Bentheuphausia amblyops. It is considered the most primitive extant krill species, well-known species of the Euphausiidae of commercial krill fisheries include Antarctic krill, Pacific krill and Northern krill. There have been many theories of the location of the order Euphausiacea, William Thomas Calman ranked the Mysidacea in the superorder Peracarida and euphausiids in the superorder Eucarida, although even up to the 1930s the order Schizopoda was advocated.
It was proposed that order Euphausiacea should be grouped with the Penaeidae in the Decapoda based on developmental similarities, as noted by Robert Gurney. The reason for debate is that krill share some morphological features of decapods. Molecular studies have not unambiguously grouped them, possibly due to the paucity of key rare species such as Bentheuphausia amblyops in krill, one study supports the monophyly of Eucarida, another groups Euphausiacea with Mysida, while yet another groups Euphausiacea with Hoplocarida
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 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 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
The nutrient-rich upwelled water stimulates the growth and reproduction of primary producers such as phytoplankton. Due to the biomass of phytoplankton and presence of water in these regions, upwelling zones can be identified by cool sea surface temperatures. The increased availability in upwelling regions results in levels of primary productivity. Approximately 25% of the global marine fish catches come from five upwellings that occupy only 5% of the total ocean area. Upwellings that are driven by coastal currents or diverging open ocean have the greatest impact on nutrient-enriched waters, the three main drivers that work together to cause upwelling are wind, Coriolis effects, and Ekman transport. They operate differently for different types of upwelling, but the effects are the same. In the overall process of upwelling, winds blow across the sea surface at a particular direction, as a result of the wind, the water is transported a net of 90 degrees from the direction of the wind due to Coriolis forces and Ekman transport.
This results in a spiral of water movement down the water column, then, it is the Coriolis forces that dictate which way the water will move, in the Northern hemisphere, the water is transported to the right of the direction of the wind. In the Southern Hemisphere, the water is transported to the left of the wind, if this net movement of water is divergent, upwelling of deep water occurs to replace the water that was lost. The major upwellings in the ocean are associated with the divergence of currents that bring deeper, coastal upwelling is the best known type of upwelling, and the most closely related to human activities as it supports some of the most productive fisheries in the world. Wind-driven currents are diverted to the right of the winds in the Northern Hemisphere, the result is a net movement of surface water at right angles to the direction of the wind, known as the Ekman transport. When Ekman transport is occurring away from the coast, surface waters moving away are replaced by deeper and denser water.
Normally, this process occurs at a rate of about 5–10 meters per day. Deep waters are rich in nutrients, including nitrate and silicic acid, Upwelling regions therefore result in very high levels of primary production in comparison to other areas of the ocean. They account for about 50% of global marine productivity, high primary production propagates up the food chain because phytoplankton are at the base of the oceanic food chain. All of these currents support major fisheries, the four major eastern boundary currents in which coastal upwelling primarily occurs are the Canary Current, Benguela Current, California Current, and Humboldt Current. The Benguela Current is the boundary of the South Atlantic subtropical gyre. The subsystems are divided by an area of permanent upwelling off of Luderitz, the California Current System is an eastern boundary current of the North Pacific that is characterized by a north and south split
Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. They are a grouping within the infraorder Cetacea, usually excluding dolphins. Whales and porpoises belong to the order Cetartiodactyla with even-toed ungulates and their closest living relatives are the hippopotamuses, the two parvorders of whales, baleen whales and toothed whales, are thought to have split apart around 34 million years ago. The whales comprise eight extant families, Balaenidae, Eschrichtiidae, Physeteridae, Whales are creatures of the open ocean, they feed, give birth and raise their young at sea. So extreme is their adaptation to life underwater that they are unable to survive on land. Whales range in size from the 2.6 metres and 135 kilograms dwarf sperm whale to the 29.9 metres and 190 metric tons blue whale, the sperm whale is the largest toothed predator on earth. Several species exhibit sexual dimorphism, in that the females are larger than males, baleen whales have no teeth, instead they have plates of baleen, a fringe-like structure used to expel water while retaining the krill and plankton which they feed on.
They use their throat pleats to expand the mouth to take in huge gulps of water, balaenids have heads that can make up 40% of their body mass to take in water. Toothed whales, on the hand, have conical teeth designed for catching fish or squid. Some species, such as whales, are well adapted for diving to great depths to catch squid. Whales have evolved from land-living mammals, as such they must breathe air regularly, though they can remain submerged for long periods. They have blowholes located on top of their heads, through air is taken in. They are warm-blooded, and have a layer of fat, or blubber, under the skin, with streamlined fusiform bodies and two limbs that are modified into flippers, whales can travel at up to 20 knots, though they are not as flexible or agile as seals. Whales produce a variety of vocalizations, notably the extended songs of the humpback whale. Although whales are widespread, most species prefer the waters of the Northern and Southern Hemispheres. Species such as humpbacks and blue whales are capable of travelling thousands of miles without feeding, males typically mate with multiple females every year, but females only mate every two to three years.
Calves are typically born in the spring and summer months and females bear all the responsibility for raising them, mothers of some species fast and nurse their young for one to two years. Once relentlessly hunted for their products, whales are now protected by international law, the North Atlantic right whales nearly became extinct in the twentieth century, with a population low of 450, and the North Pacific gray whale population is ranked Critically Endangered by the IUCN
North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere. It can be considered a subcontinent of the Americas. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the southeast by South America and the Caribbean Sea. North America covers an area of about 24,709,000 square kilometers, about 16. 5% of the land area. North America is the third largest continent by area, following Asia and Africa, and the fourth by population after Asia and Europe. In 2013, its population was estimated at nearly 565 million people in 23 independent states, or about 7. 5% of the worlds population, North America was reached by its first human populations during the last glacial period, via crossing the Bering land bridge. The so-called Paleo-Indian period is taken to have lasted until about 10,000 years ago, the Classic stage spans roughly the 6th to 13th centuries. The Pre-Columbian era ended with the migrations and the arrival of European settlers during the Age of Discovery.
Present-day cultural and ethnic patterns reflect different kind of interactions between European colonists, indigenous peoples, African slaves and their descendants, European influences are strongest in the northern parts of the continent while indigenous and African influences are relatively stronger in the south. Because of the history of colonialism, most North Americans speak English, Spanish or French, the Americas are usually accepted as having been named after the Italian explorer Amerigo Vespucci by the German cartographers Martin Waldseemüller and Matthias Ringmann. Vespucci, who explored South America between 1497 and 1502, was the first European to suggest that the Americas were not the East Indies, but a different landmass previously unknown by Europeans. In 1507, Waldseemüller produced a map, in which he placed the word America on the continent of South America. He explained the rationale for the name in the accompanying book Cosmographiae Introductio, for Waldseemüller, no one should object to the naming of the land after its discoverer.
He used the Latinized version of Vespuccis name, but in its feminine form America, following the examples of Europa and Africa. Later, other mapmakers extended the name America to the continent, In 1538. Some argue that the convention is to use the surname for naming discoveries except in the case of royalty, a minutely explored belief that has been advanced is that America was named for a Spanish sailor bearing the ancient Visigothic name of Amairick. Another is that the name is rooted in a Native American language, the term North America maintains various definitions in accordance with location and context. In Canadian English, North America may be used to refer to the United States, usage sometimes includes Greenland and Mexico, as well as offshore islands
Pixar, referred to as Pixar Animation Studios, is an American computer animation film studio based in Emeryville, California that is a subsidiary of The Walt Disney Company. Disney purchased Pixar in 2006 at a valuation of $7.4 billion, Pixar has produced seventeen feature films, beginning with Toy Story, which was the first-ever computer-animated feature film, and its most recent being Finding Dory. All 17 of its films have debuted with CinemaScore ratings of at least an A−, the studio has produced several short films. As of October 2016, its films have earned approximately $10.8 billion at the box office worldwide. Fourteen of Pixars films are among the 50 highest-grossing animated films of all time, the studio has earned sixteen Academy Awards, seven Golden Globe Awards, and eleven Grammy Awards, among many other awards and acknowledgments. Monsters, Inc. and Cars are the two films that were nominated for the award without winning it, while Cars 2, Monsters University, The Good Dinosaur. Up and Toy Story 3 were the second and third animated films to be nominated for the Academy Award for Best Picture, the first being Walt Disney Animation Studios Beauty.
Luxo Jr. a character from the studios 1986 short film of the name, is the studios mascot. The award was presented by Lucasfilms founder George Lucas, Schure kept pouring money into the computer graphics lab, an estimated $15 million, giving the group everything they desired and drove NYIT into serious financial troubles. During the following months, they resigned from CGL, found temporary jobs for about a year to avoid making Schure suspicious. He was reunited with Alvy Ray Smith, who made the journey from NYIT to Lucasfilm. At NYIT, the researchers pioneered many of the CG foundation techniques—in particular the invention of the alpha channel, Years later, the CGL produced a few frames of an experimental film called The Works. In 1982, the team working on special effects film sequences with Industrial Light & Magic. In 1983, Nolan Bushnell founded a new computer-guided animation studio called Kadabrascope as a subsidiary of his Chuck E. Cheeses Pizza Time Theatres company, only one major project was made out of the new studio, an animated Christmas movie for NBC starring Chuck E.
The animation movement would be made using Tweening instead of cel animation. After the North American Video Game Crash of 1983, Bushnell started selling some subsidiaries of PTT to keep the business afloat, sente Technologies would be sold to Bally Games and Kadabrascope would be sold to LucasFilm. The Kadabrascope assets s would be combined with the Computer Division of LucasFilm, PTT would be sold to ShowBiz Pizza Place, a competitor, in 1985. Amongst the 38 remaining employees, there were Malcolm Blanchard, David DiFrancesco, Ralph Guggenheim and Bill Reeves, Tom Duff, an NYIT member, would join Pixar after its formation
The current results from the flow of the Atlantic South Equatorial Current as it flows north along the coast of Brazil. As the current turns north through the Yucatan Channel, it is renamed the Yucatan Current, the Caribbean Current water comes from the Atlantic Ocean via the North Equatorial, North Brazil, and Guiana Currents. The circulation of the Columbia-Panama Gyre flows counter-clockwise to the Caribbean Current
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, 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
Eddy (fluid dynamics)
In fluid dynamics, an eddy is the swirling of a fluid and the reverse current created when the fluid is in a turbulent flow regime. The moving fluid creates a space devoid of downstream-flowing fluid on the side of the object. This phenomenon is naturally observed behind large emergent rocks in swift-flowing rivers, the propensity of a fluid to swirl is used to promote good fuel/air mixing in internal combustion engines. In fluid mechanics and transport phenomena, an eddy is not a property of the fluid, turbulent flow is defined as the flow in which the systems inertial forces are dominant over the viscous forces. This phenomena is described by Reynolds number, a number used to determine when turbulent flow will occur. Conceptually, the Reynolds number is the ratio between inertial forces and viscous forces, blood flow in straight sections of the arterial tree are typically laminar, but branches and curvatures in the system cause turbulent flow. Lift and drag properties of golf balls are customized by the manipulation of dimples along the surface of the ball and atmospheric currents transfer particles and organisms all across the globe.
Eddy formations circulate trash and other pollutants into concentrated areas which researchers are tracking to improve clean-up, mesoscale ocean eddies play crucial rolls in transferring heat poleward, as well as maintaining heat gradients at different depths. Eddies are common in the ocean, and range in diameter from centimeters to hundreds of kilometers, the smallest scale eddies may last for a matter of seconds, while the larger features may persist for months to years. Eddies which are between about 10 and 500 km in diameter and persist for periods of days to months are known in oceanography as mesoscale eddies. Mesoscale eddies can be split into two categories, static eddies, caused by flow around an obstacle, and transient eddies, when the ocean contains a sea surface height gradient this creates a jet or current, such as the Antarctic Circumpolar Current. This current as part of an unstable system meanders and creates eddies. Mesoscale ocean eddies are characterized by currents which flow in a circular motion around the center of the eddy.
The sense of rotation of these currents may either be cyclonic or anticyclonic, oceanic eddies are usually made of water masses that are different from those outside of the eddy. That is, the water within an eddy usually has different temperature, there is a direct link between the water mass properties of an eddy and its rotation. Warm eddies rotate anti-cyclonically, while cold eddies rotate cyclonically, because eddies may have a vigorous circulation associated with them, they are of concern to naval and commercial operations at sea. Further, because eddies transport anomalously warm or cold water as they move, they have an important influence on heat transport in certain parts of the ocean
Boundary currents are ocean currents with dynamics determined by the presence of a coastline, and fall into two distinct categories, western boundary currents and eastern boundary currents. Eastern boundary currents are relatively shallow and slow-flowing and they are found on the eastern side of oceanic basins. Coastal upwelling often brings nutrient-rich water into eastern boundary current regions, western boundary currents are warm, deep and fast flowing currents that form on the west side of ocean basins due to western intensification. They carry warm water from the tropics poleward, examples include the Gulf Stream, the Agulhas Current, and the Kuroshio. Western intensification is the intensification of the arm of an oceanic current. The trade winds blow westward in the tropics, and the westerlies blow eastward at mid-latitudes and this wind pattern applies a stress to the subtropical ocean surface with negative curl in the northern hemisphere and a positive curl in the southern hemisphere.
The resulting Sverdrup transport is equatorward in both cases, western intensification occurs in the polar gyres, where the sign of the wind stress curl and the direction of the resulting currents are reversed. It is because of western intensification that the currents on the boundary of a basin are stronger than those on the eastern boundary. Western intensification was first explained by the American oceanographer Henry Stommel, the wind is blowing towards the west at y =0 and towards the east at y = b. Such currents are observed to be faster, deeper and warmer than their eastern counterparts. The streamlines exhibit a behavior in all directions, with the height contours demonstrating a nearly parallel relation to the streamlines. The physics of western intensification can be understood through a mechanism that helps maintain the balance along an ocean gyre. He assumed a geostrophic flow, while neglecting any frictional or viscosity effects. Sverdrup introduced a potential vorticity argument to connect the net, interior flow of the oceans to the wind stress.
This is accomplished via a decrease in planetary vorticity, a phenomenon attainable through an equator-wardly directed, the opposite is applicable when Ekman divergence is induced, leading to Ekman absorption and a subsequent, water column stretching and poleward return flow, a characteristic of sub-polar gyres. This return flow, as shown by Stommel, occurs in a meridional current, to balance the vorticity source induced by the wind stress forcing, Stommel introduced a linear frictional term in the Sverdrup equation, functioning as the vorticity sink. Walter Munk further implemented Stommels theory of western intensification by using a more realistic frictional term, Ekman Transport Ocean Gyres Sverdrup Balance Thurman, Harold V. Trujillo, Alan P. On the wind-driven ocean circulation, J. Meteorol, Ocean Currents, A Derivative of the Encyclopedia of Ocean Sciences