1.
Pacific Ocean
–
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
Pacific Ocean
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Maris Pacifici by
Ortelius (1589). One of the first printed maps to show the Pacific Ocean; see also
Waldseemüller map (1507).
Pacific Ocean
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The Pacific Ocean
Pacific Ocean
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USS
Lexington under air attack on 8 May 1942 during the
Battle of the Coral Sea
Pacific Ocean
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Map of the Pacific Ocean during European Exploration, circa 1702–1707.
2.
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
Ocean current
–
Major ocean surface currents (Source:
NOAA)
Ocean current
–
The ocean currents.
Ocean current
–
The
bathymetry of the
Kerguelen Plateau in the
Southern Ocean governs the course of the new current part of the global network of ocean currents (Source:
CSIRO)
Ocean current
–
Coupling data collected by NASA/JPL by several different satellite-borne sensors, researchers have been able to "break through" the ocean's surface to detect "Meddies" -- super-salty warm-water eddies that originate in the Mediterranean Sea and then sink more than a half-mile underwater in the Atlantic Ocean. The Meddies are shown in red in this scientific figure.
3.
North America
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North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere. It can also 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, Africa, 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, Asia 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, alternatively, usage sometimes includes Greenland and Mexico, as well as offshore islands
North America
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Map of North America, from 1621.
North America
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North America
North America
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The
El Castillo pyramid, at
Chichén Itzá, Mexico.
North America
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Benjamin West 's
The Death of General Wolfe (1771) depicting the
Battle of the Plains of Abraham.
4.
British Columbia
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British Columbia is the westernmost province of Canada, with a population of more than four million people located between the Pacific Ocean and the Rocky Mountains. British Columbia is also a component of the Pacific Northwest and the Cascadia bioregion, along with the U. S. states of Idaho, Oregon, Washington and Alaska. The first British settlement in the area was Fort Victoria, established in 1843, subsequently, on the mainland, the Colony of British Columbia was founded by Richard Clement Moody and the Royal Engineers, Columbia Detachment, in response to the Fraser Canyon Gold Rush. Port Moody is named after him, in 1866, Vancouver Island became part of the colony of British Columbia, and Victoria became the united colonys capital. In 1871, British Columbia became the province of Canada. Its Latin motto is Splendor sine occasu, the capital of British Columbia remains Victoria, the fifteenth-largest metropolitan region in Canada, named for the Queen who created the original European colonies. The largest city is Vancouver, the third-largest metropolitan area in Canada, the largest in Western Canada, in October 2013, British Columbia had an estimated population of 4,606,371. British Columbia evolved from British possessions that were established in what is now British Columbia by 1871, First Nations, the original inhabitants of the land, have a history of at least 10,000 years in the area. Today there are few treaties and the question of Aboriginal Title, notably, the Tsilhqotin Nation has established Aboriginal title to a portion of their territory, as a result of the recent Supreme Court of Canada decision. BCs economy is diverse, with service producing industries accounting for the largest portion of the provinces GDP and it is the endpoint of transcontinental railways, and the site of major Pacific ports that enable international trade. Though less than 5% of its vast 944,735 km2 land is arable and its climate encourages outdoor recreation and tourism, though its economic mainstay has long been resource extraction, principally logging, farming, and mining. Vancouver, the provinces largest city and metropolitan area, also serves as the headquarters of many western-based natural resource companies and it also benefits from a strong housing market and a per capita income well above the national average. The Northern Interior region has a climate with very cold winters. The climate of Vancouver is by far the mildest winter climate of the major Canadian cities, the provinces name was chosen by Queen Victoria, when the Colony of British Columbia, i. e. the Mainland, became a British colony in 1858. The current southern border of British Columbia was established by the 1846 Oregon Treaty, British Columbias land area is 944,735 square kilometres. British Columbias rugged coastline stretches for more than 27,000 kilometres and it is the only province in Canada that borders the Pacific Ocean. British Columbias capital is Victoria, located at the tip of Vancouver Island. Only a narrow strip of the Island, from Campbell River to Victoria, is significantly populated, much of the western part of Vancouver Island and the rest of the coast is covered by thick, tall and sometimes impenetrable temperate rainforest
British Columbia
–
Strait of Georgia, near
Vancouver.
British Columbia
–
Flag
British Columbia
–
The Okanagan region has a climate suitable to vineyards.
British Columbia
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Mount Robson,
Canadian Rockies, BC
5.
Baja California Peninsula
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The Baja California Peninsula is a peninsula in Northwestern Mexico. Its land mass separates the Pacific Ocean from the Gulf of California, the peninsula extends 1,247 km from Mexicali, Baja California in the north to Cabo San Lucas, Baja California Sur in the south. It ranges from 40 km at its narrowest to 320 km at its widest point and has approximately 3,000 km of coastline, the total area of the Baja California Peninsula is 143,390 km2. The peninsula is separated from mainland Mexico by the Gulf of California, there are four main desert areas on the peninsula, the San Felipe Desert, the Central Coast Desert, the Vizcaíno Desert and the Magdalena Plain Desert. The land of California existed as a myth among European explorers before it was discovered, the earliest known mention of the idea of California was in the 1510 romance novel Las Sergas de Esplandián by Spanish author Garci Rodríguez de Montalvo. Its first expedition reached the Gulf of California and California, nevertheless, the idea of the island persisted for well over a century and was included in many maps. 1532, Hernán Cortés sends three ships North along the coast of Mexico in search of the Island of California, the three ships disappear without a trace. 1533, Cortés sends a mission to search for the lost ships. Pilot Fortún Ximénez leads a mutiny and founds a settlement in the Bay of La Paz before being killed,1539, Francisco de Ulloa explores both coasts. 1690s–1800s, Spanish settlement and colonization in lower Las Californias, the first Spanish missions in Baja California are established by Jesuit missionaries,1701, The first report and a map showing California as a peninsula rather than an island is sent to Europe. 1767, Jesuits expelled, Franciscans take over the Baja missions,1769, Franciscans go with the Portola expedition to establish new missions in Alta California. Control of the existing Baja missions passes to the Dominican Order,1773, Francisco Palóus line demarcates Franciscan and Dominican areas of mission control. 1804, Las Californias divided into Alta and Baja California, using Palóus line, 1810–1821, Mexican War of Independence 1821, First Mexican Empire, Baja California Territory established, covering Baja California Peninsula. 1847, The Battle of La Paz and the Siege of La Paz occurs,1848, Treaty of Guadalupe Hidalgo cedes Alta California to the United States. As a U. S. territory it receives the California Gold Rush,1850, California admitted to U. S. statehood. 1853, William Walker, with 45 men, captures the city of La Paz. Mexico forces him to retreat a few months later, 1930–31, The Territory of Baja California is further divided into Northern and Southern territories. 1952, The North Territory of Baja California becomes the 29th State of Mexico, the southern portion, below 28°N, remains a federally administered territory
Baja California Peninsula
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Satellite image of the Baja California Peninsula
Baja California Peninsula
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Isla Partida, which is part of the
San Lorenzo Marine Archipelago National Park
Baja California Peninsula
–
Port of
Cabo San Lucas
Baja California Peninsula
–
Baja California as seen in April 1984, from the bay of a Space Shuttle (
STS 41)
6.
Eastern boundary current
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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, broad 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, narrow, 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 also 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, narrower 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
Eastern boundary current
–
The main ocean currents involved with the North Pacific Gyre
7.
Upwelling
–
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, then 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, colder, 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, colder, 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, phosphate 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 also characterized by a north and south split
Upwelling
–
Areas of upwelling in red
Upwelling
–
If the wind blows parallel to the coast in the northern hemisphere (such as the coast of California, where the wind blows South), then
Ekman transport can produce a net movement of surface water 90° to the right. This may result in coastal upwelling.
Upwelling
–
Unusually strong winds from the east push warm (red) surface water towards Africa, allowing cold (blue) water to upwell along the Sumatran coast
Upwelling
–
During an
El Niño, wind indirectly drives warm water to the South American coast, reducing the effects of cold upwelling
8.
Humboldt Current
–
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
Humboldt Current
–
Humboldt Current
Humboldt Current
–
La Silla is in the Southern outskirts of the
Atacama Desert, one of the driest places on Earth, it may come as a surprise to see cloud formations result of the Peruvian Humboldt Current.
Humboldt Current
–
Fisheries science
Humboldt Current
–
Management
9.
Canary Current
–
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
Canary Current
–
EUMETSAT (European Meteorological satellite) image from Northwest Africa, showing the lack of clouds on the upwelling waters of the Canary Current
10.
Benguela 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, 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
Benguela Current
–
The courses of the warm Agulhas current (red) along the east coast of South Africa, and the cold Benguela current (blue) along the west coast. Note that the Benguela current does not originate from Antarctic waters in the South Atlantic Ocean, but from upwelling of water from the cold depths of the Atlantic Ocean against the west coast of the continent. The two currents do not "meet" anywhere along the south coast of Africa.
Benguela Current
–
The red areas show major upwelling areas. The Benguela Current is on the southwest coast of Africa.
11.
Somali Current
–
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
Somali Current
–
Southward Somali Current during Northeast Indian Monsoon
12.
North Pacific Gyre
–
The North Pacific Gyre, located in the northern Pacific Ocean, is one of the five major oceanic gyres. This gyre covers most of the northern Pacific Ocean and it is the largest ecosystem on Earth, located between the equator and 50° N latitude, and comprising 20 million square kilometers. It is the site of an unusually intense collection of marine debris. Ecosystem of the North Pacific Subtropical Gyre North Atlantic Garbage Patch Great Pacific Garbage Patch Ocean current Marine Pollution South Atlantic Gyre Ocean currents
North Pacific Gyre
–
The main ocean currents involved with the North Pacific Gyre
13.
Latitude
–
In geography, latitude is a geographic coordinate that specifies the north–south position of a point on the Earths surface. Latitude is an angle which ranges from 0° at the Equator to 90° at the poles, lines of constant latitude, or parallels, run east–west as circles parallel to the equator. Latitude is used together with longitude to specify the location of features on the surface of the Earth. Without qualification the term latitude should be taken to be the latitude as defined in the following sections. Also defined are six auxiliary latitudes which are used in special applications, there is a separate article on the History of latitude measurements. Two levels of abstraction are employed in the definition of latitude and longitude, in the first step the physical surface is modelled by the geoid, a surface which approximates the mean sea level over the oceans and its continuation under the land masses. The second step is to approximate the geoid by a mathematically simpler reference surface, the simplest choice for the reference surface is a sphere, but the geoid is more accurately modelled by an ellipsoid. The definitions of latitude and longitude on such surfaces are detailed in the following sections. Lines of constant latitude and longitude together constitute a graticule on the reference surface, latitude and longitude together with some specification of height constitute a geographic coordinate system as defined in the specification of the ISO19111 standard. This is of importance in accurate applications, such as a Global Positioning System, but in common usage, where high accuracy is not required. In English texts the latitude angle, defined below, is denoted by the Greek lower-case letter phi. It is measured in degrees, minutes and seconds or decimal degrees, the precise measurement of latitude requires an understanding of the gravitational field of the Earth, either to set up theodolites or to determine GPS satellite orbits. The study of the figure of the Earth together with its field is the science of geodesy. These topics are not discussed in this article and this article relates to coordinate systems for the Earth, it may be extended to cover the Moon, planets and other celestial objects by a simple change of nomenclature. The primary reference points are the poles where the axis of rotation of the Earth intersects the reference surface, the plane through the centre of the Earth and perpendicular to the rotation axis intersects the surface at a great circle called the Equator. Planes parallel to the plane intersect the surface in circles of constant latitude. The Equator has a latitude of 0°, the North Pole has a latitude of 90° North, the latitude of an arbitrary point is the angle between the equatorial plane and the radius to that point. The latitude, as defined in this way for the sphere, is termed the spherical latitude
Latitude
–
A graticule on the Earth as a
sphere or an
ellipsoid. The lines from pole to pole are lines of constant
longitude, or meridians. The circles parallel to the
equator are lines of constant latitude, or parallels. The graticule determines the latitude and longitude of points on the surface. In this example meridians are spaced at 6° intervals and parallels at 4° intervals.
14.
Half Moon Bay, California
–
Half Moon Bay is a coastal city in San Mateo County, California, United States. Its population was 11,324 as of the 2010 census, immediately at the north of Half Moon Bay is the Pillar Point Harbor and the unincorporated community of Princeton-by-the-Sea. The urban area had a population of 20,713 at the same census, Half Moon Bay began as a rural agriculture area, primarily used for grazing of cattle, horses, and oxen used by Mission San Francisco de Asis. Following the secularization of the Mission, Tiburcio Vásquez received the Rancho Corral de Tierra Mexican land grant in 1839, the community began to develop in the 1840s as the first real town in San Mateo County. Known originally as San Benito, the town was renamed Spanishtown, Spanishtown became a racially diverse community, settled by Canadians, Chinese, English, Germans, Irish, Mexicans, Italians, Scots, Portuguese, and Pacific Islanders. Regular stagecoach service was established with San Mateo, coaches also served the communities of Purissima, Lobitos, levy Brothers opened a department store in downtown Half Moon Bay. Spanishtown was officially renamed Half Moon Bay in 1874, the area grew very slowly, even after the Ocean Shore Railroad began serving the community in 1907. The construction of Pedro Mountain Road in 1914 provided better access to San Francisco, the USS DeLong ran aground at Half Moon Bay 1 December 1921. During Prohibition rum runners took advantage of dense fog and hidden coves in the area to serve a number of roadhouses and inns, some of which operate today as restaurants. Real growth in the area came after World War II with the construction of numerous subdivisions, the city preserves a historic downtown district which includes historic buildings dating as far back as 1869. In 2008, financial setbacks endangered the citys viability, the economic crisis severely affected tourism, which generates the most revenue, and that just at the time when the city had finalized a $18 million settlement over a property lawsuit. As the municipal budget was typically $14 million or less, city fathers had issued bonds with annual payments of approximately $1 million over 25 years, as a result of these combined fiscal obstacles, the threat of bankruptcy was very real. Dozens of meetings were held in order to decide where the budget should be cut and finally 75% of municipal employees were laid off, also, employee contributions toward retirement benefits were raised. However, the city sought to regain the money paid in the settlement. Since then, the Citys finances have shown great improvement, the City was able to retire the first of its two 30-year Judgment Obligation Bonds a full 20 years early. The early retirement will save the City over $426,000 in annual General Fund expenses starting in 2015-16, as of the publication of the Fiscal Year 2015/16 Budget the General Fund budget is balanced and has a structural surplus of $4.0 Million. The General Fund budget is projected to have a significant structural surplus in the following four years according to revenue. Half Moon Bay is located at 37°27′32″N 122°26′13″W, approximately 25 miles south of San Francisco,10 miles west of San Mateo, neighboring towns include El Granada, Princeton-by-the-Sea, Moss Beach, and Montara to the north and Purissima, San Gregorio, and Pescadero to the south
Half Moon Bay, California
–
Pillar Point Harbor
Half Moon Bay, California
–
A valley floor outside the city
Half Moon Bay, California
–
The USS DeLong, run aground
Half Moon Bay, California
–
Aerial view of Pillar Point Harbor. View is to the east.
15.
San Francisco
–
San Francisco, officially the City and County of San Francisco, is the cultural, commercial, and financial center of Northern California. It is the birthplace of the United Nations, the California Gold Rush of 1849 brought rapid growth, making it the largest city on the West Coast at the time. San Francisco became a consolidated city-county in 1856, after three-quarters of the city was destroyed by the 1906 earthquake and fire, San Francisco was quickly rebuilt, hosting the Panama-Pacific International Exposition nine years later. In World War II, San Francisco was a port of embarkation for service members shipping out to the Pacific Theater. Politically, the city votes strongly along liberal Democratic Party lines, San Francisco is also the headquarters of five major banking institutions and various other companies such as Levi Strauss & Co. Dolby, Airbnb, Weebly, Pacific Gas and Electric Company, Yelp, Pinterest, Twitter, Uber, Lyft, Mozilla, Wikimedia Foundation, as of 2016, San Francisco is ranked high on world liveability rankings. The earliest archaeological evidence of habitation of the territory of the city of San Francisco dates to 3000 BC. Upon independence from Spain in 1821, the became part of Mexico. Under Mexican rule, the system gradually ended, and its lands became privatized. In 1835, Englishman William Richardson erected the first independent homestead, together with Alcalde Francisco de Haro, he laid out a street plan for the expanded settlement, and the town, named Yerba Buena, began to attract American settlers. Commodore John D. Sloat claimed California for the United States on July 7,1846, during the Mexican–American War, montgomery arrived to claim Yerba Buena two days later. Yerba Buena was renamed San Francisco on January 30 of the next year, despite its attractive location as a port and naval base, San Francisco was still a small settlement with inhospitable geography. The California Gold Rush brought a flood of treasure seekers, with their sourdough bread in tow, prospectors accumulated in San Francisco over rival Benicia, raising the population from 1,000 in 1848 to 25,000 by December 1849. The promise of fabulous riches was so strong that crews on arriving vessels deserted and rushed off to the gold fields, leaving behind a forest of masts in San Francisco harbor. Some of these approximately 500 abandoned ships were used at times as storeships, saloons and hotels, many were left to rot, by 1851 the harbor was extended out into the bay by wharves while buildings were erected on piles among the ships. By 1870 Yerba Buena Cove had been filled to create new land, buried ships are occasionally exposed when foundations are dug for new buildings. California was quickly granted statehood in 1850 and the U. S. military built Fort Point at the Golden Gate, silver discoveries, including the Comstock Lode in Nevada in 1859, further drove rapid population growth. With hordes of fortune seekers streaming through the city, lawlessness was common, and the Barbary Coast section of town gained notoriety as a haven for criminals, prostitution, entrepreneurs sought to capitalize on the wealth generated by the Gold Rush
San Francisco
–
San Francisco and the
Golden Gate Bridge from
Marin Headlands
San Francisco
–
Mission San Francisco de Asís (Mission Dolores)
San Francisco
–
1853
United States Coast Survey Map
San Francisco
–
Francis Samuel Marryat, Hilltop of San Francisco, California, Looking toward the Bay, 1849. M.& N. Hanhart Chromolithograph
16.
Ekman Effect
–
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
Ekman Effect
–
Ekman spiral effect. 1. Wind 2. force from above 3. Effective direction of the current 4. Coriolis effect
17.
Fog
–
Fog consists of visible cloud water droplets or ice crystals suspended in the air at or near the Earths surface. Fog can be considered a type of low-lying cloud and is influenced by nearby bodies of water, topography. In turn, fog has affected many human activities, such as shipping, travel, the term fog is typically distinguished from the more generic term cloud in that fog is low-lying, and the moisture in the fog is often generated locally. By definition, fog reduces visibility to less than 1 kilometre, for aviation purposes in the UK, a visibility of less than 5 kilometres but greater than 999 metres is considered to be mist if the relative humidity is 70% or greater, below 70%, haze is reported. Fog forms when the difference between air temperature and dew point is less than 2.5 °C or 4 °F, Fog begins to form when water vapor condenses into tiny liquid water droplets suspended in the air. Water vapor normally begins to condense on condensation nuclei such as dust, ice, Fog, like its elevated cousin stratus, is a stable cloud deck which tends to form when a cool, stable air mass is trapped underneath a warm air mass. Fog normally occurs at a relative humidity near 100% and this occurs from either added moisture in the air, or falling ambient air temperature. However, fog can form at lower humidities, and can fail to form with relative humidity at 100%. At 100% relative humidity, the air cannot hold additional moisture, thus, Fog can form suddenly and can dissipate just as rapidly. The sudden formation of fog is known as flash fog, Fog commonly produces precipitation in the form of drizzle or very light snow. Drizzle occurs when the humidity of fog attains 100% and the cloud droplets begin to coalesce into larger droplets. This can occur when the fog layer is lifted and cooled sufficiently, drizzle becomes freezing drizzle when the temperature at the surface drops below the freezing point. The inversion boundary varies its altitude primarily in response to the weight of the air above it, the marine layer, and any fogbank it may contain, will be squashed when the pressure is high, and conversely, may expand upwards when the pressure above it is lowering. Fog can form in a number of ways, depending on how the cooling that caused the condensation occurred, radiation fog is formed by the cooling of land after sunset by thermal radiation in calm conditions with clear sky. The warm ground produces condensation in the air by heat conduction. In perfect calm the fog layer can be less than a meter deep, radiation fogs occur at night, and usually do not last long after sunrise, but they can persist all day in the winter months especially in areas bounded by high ground. Radiation fog is most common in autumn and early winter, examples of this phenomenon include the Tule fog. Ground fog is fog that obscures less than 60% of the sky, advection fog occurs when moist air passes over a cool surface by advection and is cooled
Fog
–
Fog, in the form of a cloud, descends upon a
High Desert community in the western US, while leaving the mountain exposed.
Fog
–
Minute droplets of water constitute this after-dark radiation fog, with the ambient temperature −2
°C (28
°F)
Fog
–
Up-close view of water particles forming fog
Fog
–
Heavier fog on a road near Baden, Austria
18.
New York City
–
The City of New York, often called New York City or simply New York, is the most populous city in the United States. With an estimated 2015 population of 8,550,405 distributed over an area of about 302.6 square miles. Located at the tip of the state of New York. Home to the headquarters of the United Nations, New York is an important center for international diplomacy and has described as the cultural and financial capital of the world. Situated on one of the worlds largest natural harbors, New York City consists of five boroughs, the five boroughs – Brooklyn, Queens, Manhattan, The Bronx, and Staten Island – were consolidated into a single city in 1898. In 2013, the MSA produced a gross metropolitan product of nearly US$1.39 trillion, in 2012, the CSA generated a GMP of over US$1.55 trillion. NYCs MSA and CSA GDP are higher than all but 11 and 12 countries, New York City traces its origin to its 1624 founding in Lower Manhattan as a trading post by colonists of the Dutch Republic and was named New Amsterdam in 1626. The city and its surroundings came under English control in 1664 and were renamed New York after King Charles II of England granted the lands to his brother, New York served as the capital of the United States from 1785 until 1790. It has been the countrys largest city since 1790, the Statue of Liberty greeted millions of immigrants as they came to the Americas by ship in the late 19th and early 20th centuries and is a symbol of the United States and its democracy. In the 21st century, New York has emerged as a node of creativity and entrepreneurship, social tolerance. Several sources have ranked New York the most photographed city in the world, the names of many of the citys bridges, tapered skyscrapers, and parks are known around the world. Manhattans real estate market is among the most expensive in the world, Manhattans Chinatown incorporates the highest concentration of Chinese people in the Western Hemisphere, with multiple signature Chinatowns developing across the city. Providing continuous 24/7 service, the New York City Subway is one of the most extensive metro systems worldwide, with 472 stations in operation. Over 120 colleges and universities are located in New York City, including Columbia University, New York University, and Rockefeller University, during the Wisconsinan glaciation, the New York City region was situated at the edge of a large ice sheet over 1,000 feet in depth. The ice sheet scraped away large amounts of soil, leaving the bedrock that serves as the foundation for much of New York City today. Later on, movement of the ice sheet would contribute to the separation of what are now Long Island and Staten Island. The first documented visit by a European was in 1524 by Giovanni da Verrazzano, a Florentine explorer in the service of the French crown and he claimed the area for France and named it Nouvelle Angoulême. Heavy ice kept him from further exploration, and he returned to Spain in August and he proceeded to sail up what the Dutch would name the North River, named first by Hudson as the Mauritius after Maurice, Prince of Orange
New York City
–
Clockwise, from top:
Midtown Manhattan,
Times Square, the
Unisphere in
Queens, the
Brooklyn Bridge,
Lower Manhattan with
One World Trade Center,
Central Park, the
headquarters of the United Nations, and the
Statue of Liberty
New York City
–
New Amsterdam, centered in the eventual
Lower Manhattan, in 1664, the year
England took control and renamed it "New York".
New York City
–
The
Battle of Long Island, the largest battle of the
American Revolution, took place in
Brooklyn in 1776.
New York City
–
Broadway follows the Native American Wickquasgeck Trail through Manhattan.
19.
Eureka, CA
–
Eureka is the principal city and county seat of Humboldt County in the Redwood Empire region of California. The city is located on U. S. Route 101 on the shores of Humboldt Bay,270 miles north of San Francisco and 100 miles south of the Oregon border. At the 2010 census, the population of the city was 27,191, Eureka is the largest coastal city between San Francisco and Portland, and the westernmost city of more than 25,000 residents in the 48 contiguous states. It is the center for government, health care, trade. Greater Eureka, one of Californias major commercial fishing ports, is the location of the largest deep-water port between San Francisco and Coos Bay, a stretch of about 500 miles. The headquarters of both the Six Rivers National Forest and the North Coast Redwoods District of the California State Parks System are in Eureka. As entrepôt for hundreds of mills that once existed in the area. Eureka is home to Californias oldest zoo, the Sequoia Park Zoo, Eurekas Pacific coastal location on Humboldt Bay, adjacent to abundant redwood forests, provided the reason for settlement of this 19th-century seaport town. Before the arrival of Euro-American settlers, including farmers, miners, fishermen, and loggers, the Wiyot people lived in Jaroujiji, now known as Eureka, for thousands of years prior to European arrival. They are the farthest-southwest people whose language has Algonquian roots and their traditional coastal homeland ranged from the lower Mad River through Humboldt Bay and south along the lower basin of the Eel River. The Wiyot are particularly known for their basketry and fishery management, an extensive collection of intricate basketry of the areas indigenous groups exists in the Clarke Historical Museum in Old Town Eureka. As of 2013, Eureka High School has the largest Yurok language program in California, the timing of this discovery would lead to the May 13,1850 founding of the settlement of Eureka on its shore by the Union and Mendocino Exploring companies. Eureka received its name from a Greek word meaning I have found it and this exuberant statement of successful gold rush miners is also the official Motto of the State of California. Eureka is the only U. S. location to use the seal as the state for its seal. In the United States, Eureka, California is the largest of about a dozen towns, the first Europeans venturing into Humboldt Bay encountered the indigenous Wiyot. Records of early forays into the bay in 1806 reported that the violence of the indigenous people made it nearly impossible for landing parties to survey the area. After 1850, Europeans ultimately overwhelmed the Wiyot, whose maximum population before the Europeans was in the hundreds in the area of what would become the primary city. The 1860 Wiyot Massacre took place on Indian Island in the spring of 1860, committed by a group of locals, thought to be primarily Eureka businessmen
Eureka, CA
–
Aerial view: Eureka on Humboldt Bay
Eureka, CA
–
A Humboldt Bay (Woodley Island) view of
Indian Island (both within the city limits) and the memorial to fisherman
Eureka, CA
–
Mill yard across the bay from Eureka
Eureka, CA
–
The
Carson Mansion (1886) in Eureka's
Old Town
20.
Whale
–
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, dolphins 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, Balaenopteridae, Balaenidae, Cetotheriidae, Eschrichtiidae, Monodontidae, Physeteridae, Kogiidae, Whales are creatures of the open ocean, they feed, mate, give birth, suckle 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
Whale
–
Southern right whale
Whale
–
The
hippopotamuses are the
sister clade to the
Cetacea, which contains whales,
dolphins and
porpoises.
Whale
–
Basilosaurus skeleton
Whale
–
Features of a
sperm whale skeleton
21.
Seabird
–
Seabirds are birds that are adapted to life within the marine environment. The first seabirds evolved in the Cretaceous period, and modern seabird families emerged in the Paleogene, in general, seabirds live longer, breed later and have fewer young than other birds do, but they invest a great deal of time in their young. Most species nest in colonies, which can vary in size from a few birds to millions. Many species are famous for undertaking long annual migrations, crossing the equator or circumnavigating the Earth in some cases and they feed both at the oceans surface and below it, and even feed on each other. Seabirds can be highly pelagic, coastal, or in some cases spend a part of the year away from the sea entirely, Seabirds and humans have a long history together, they have provided food to hunters, guided fishermen to fishing stocks and led sailors to land. Many species are threatened by human activities, and conservation efforts are under way. There exists no single definition of which groups, families and species are seabirds, and most definitions are in some way arbitrary. In the words of two scientists, The one common characteristic that all seabirds share is that they feed in saltwater. However, by all of the Sphenisciformes and Procellariiformes, all of the Pelecaniformes except the darters. The phalaropes are usually included as well, since although they are waders, loons and grebes, which nest on lakes but winter at sea, are usually categorized as water birds, not seabirds. Although there are a number of sea ducks in the family Anatidae that are truly marine in the winter, many waders and herons are also highly marine, living on the seas edge, but are also not treated as seabirds. Seabirds, by virtue of living in a depositional environment, are well represented in the fossil record. In the Paleogene the seas were dominated by early Procellariidae, giant penguins, modern genera began their wide radiation in the Miocene, although the genus Puffinus might date back to the Oligocene. The highest diversity of seabirds apparently existed during the Late Miocene, Seabirds have made numerous adaptations to living on and feeding in the sea. Wing morphology has been shaped by the niche an individual species or family has evolved, so that looking at a wings shape, longer wings and low wing loading are typical of more pelagic species, while diving species have shorter wings. Seabirds also almost always have webbed feet, to aid movement on the surface as well as assisting diving in some species. The Procellariiformes are unusual among birds in having a sense of smell, which is used to find widely distributed food in a vast ocean. Salt glands are used by seabirds to deal with the salt they ingest by drinking and feeding, the excretions from these glands are almost pure sodium chloride
Seabird
–
The
sooty tern is highly aerial and marine and will spend months flying at sea, returning to land only for breeding.
Seabird
–
The Cretaceous seabird Hesperornis
Seabird
–
Cormorants, like this
double-crested cormorant, have plumage that is partly wettable, allowing them to dive without fighting buoyancy.
Seabird
–
Wilson's storm petrels pattering on the water's surface
22.
Fisheries
–
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
Fisheries
–
Salmon spawn in a salmon fishery within the
Becharof Wilderness in
Southwest Alaska.
Fisheries
–
Fishermen in
Sesimbra, Portugal
Fisheries
–
Wild
Fisheries
23.
Scripps Institution of Oceanography
–
Hundreds of ocean and Earth scientists conduct research with the aid of oceanographic research vessels and shorebased laboratories. Its Old Scripps Building is a U. S. National Historic Landmark, SIO is a department of the University of California, San Diego. The public explorations center of the institution is the Birch Aquarium at Scripps, since becoming part of the University of California in 1912, the institution has expanded its scope to include studies of the physics, chemistry, geology, biology, and climate of Earth. Dr. Margaret Leinen took office as Vice Chancellor for Marine Sciences, Director of Scripps Institution of Oceanography, Scripps publishes explorations now, an e-magazine of ocean and earth science. To seek, teach, and communicate scientific understanding of the oceans, atmosphere, Earth, and other planets for the benefit of society, Scripps Institution of Oceanography was founded in 1903 as the Marine Biological Association of San Diego, an independent biological research laboratory. It was proposed and incorporated by a committee of the San Diego Chamber of Commerce, led by local activist and they fully funded the institution for its first decade. It began institutional life in the boathouse of the Hotel del Coronado located on San Diego Bay and it re-located in 1905 to the La Jolla area on the head above La Jolla Cove, and finally in 1907 to its present location. In 1912 Scripps became part of the University of California and was renamed the Scripps Institution for Biological Research, the name was changed to Scripps Institution of Oceanography in October 1925. The Old Scripps Building, designed by Irving Gill, was declared a National Historic Landmark in 1982, architect Barton Myers designed the current Scripps Building. The institutions research programs encompass biological, physical, chemical, geological, Scripps also studies the interaction of the oceans with both the atmospheric climate and environmental concerns on terra firma. Related to this research, Scripps offers undergraduate and graduate degrees, today, the Scripps staff of 1,300 includes approximately 235 faculty,180 other scientists and some 300 graduate students, with an annual budget of more than $195 million. The institution operates a fleet of three research vessels and the research platform R/P FLIP for oceanographic research. – RV Ellen B. Scripps 1966–1992 – RV Thomas Washington 1969–2014 – RV Melville 1973–, in 2014, the institution and its Keeling Curve measurement of atmospheric carbon dioxide levels were featured as a plot point in an episode of HBOs The Newsroom. In 2008, Scripps Institution of Oceanography was the subject of a category on the TV game show Jeopardy, Scripps has been a story element in numerous fictional works. Array Network Facility The Scripps Research Institute, a neighboring, woods Hole Oceanographic Institution, a similar research facility on the east coast of the USA. Monterey Bay Aquarium Research Institute, a private, non-profit oceanographic research center in Moss Landing, Scripps Institution of Oceanography, First Fifty Years Helen Raitt and Beatrice Moulton. Los Angeles, W. Ritchie Press,1967, Scripps Institution of Oceanography, Probing the Oceans,1936 to 1976 Elizabeth Noble Shor
Scripps Institution of Oceanography
–
A view of Scripps Institution of Oceanography in 2011, taken from the Birch Aquarium.
Scripps Institution of Oceanography
–
Scripps Institution of Oceanography pier
Scripps Institution of Oceanography
–
Scripps Institution of Oceanography researchers at sea
Scripps Institution of Oceanography
–
Scripps research vessel Roger Revelle
24.
Phytoplankton
–
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
Phytoplankton
–
Diatoms are one of the most common types of phytoplankton.
Phytoplankton
–
Phytoplankton come in many shapes and sizes.
Phytoplankton
–
Phytoplankton are the foundation of the oceanic food chain.
Phytoplankton
–
When two currents collide (here the
Oyashio and
Kuroshio currents) they create
eddies. Phytoplankton concentrates along the boundaries of the eddies, tracing the motion of the water.
25.
Krill
–
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 also 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, seals, penguins, squid 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, Philippines 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 also 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, later, 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 later 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
Krill
–
Euphausiacea
Krill
–
A krill swarm
Krill
–
Krill anatomy explained, using
Euphausia superba as a model
Krill
–
The
gills of krill are externally visible.
26.
Eddies
–
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, oceanic and atmospheric currents transfer particles, debris, 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 also 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
Eddies
–
Downwind of obstacles, in this case, the
Madeira and the
Canary Islands off the west African coast, eddies create turbulent patterns called vortex streets.
Eddies
–
When two currents (in this case the
Oyashio and
Kuroshio currents) collide, they create eddies.
Phytoplankton become concentrated along the boundaries of these eddies, tracing out the motions of the water.
27.
Walt Disney Pictures
–
Walt Disney Pictures, Inc. is an American film production company and a subsidiary of Walt Disney Studios, owned by The Walt Disney Company. The subsidiary is based at the Walt Disney Studios in Burbank, California and it took on its current name in 1983. Today, in conjunction with the units of Walt Disney Studios. Animated films such as those by Walt Disney Animation Studios and Pixar Animation Studios are released under this brand. Pirates of the Caribbean series is the corporations most successful franchise, the studios predecessor was founded as the Disney Brothers Cartoon Studio, by filmmaker Walt Disney and his business partner and brother, Roy, in 1923. The creation of Mickey Mouse and subsequent short films and merchandise generated revenue for the studio which was renamed as The Walt Disney Studio at the Hyperion Studio in 1926, in 1929, it was renamed again to Walt Disney Productions. With the profits from Snow White, Walt relocated to a studio in Burbank. In the 1940s, Disney began experimenting with full-length live-action films, with the introduction of hybrid live action-animated films such as The Reluctant Dragon and Song of the South. By 1953, the company ended their agreements with such third-party distributors as RKO Radio Pictures and United Artists and formed their own distribution company, Buena Vista Distribution. The Walt Disney Productions in April 1983 incorporated its film division as Walt Disney Pictures, Inc. Touchstone Films banner was used by then new Disney CEO Michael Eisner in the 1984–85 television season with the short lived western, Wildside. The next TV season, Touchstone produced a hit with The Golden Girls, David Hoberman was promoted to president of production, Walt Disney Pictures in April 1988. In April 1994, Hoberman was promoted to president of motion pictures at Walt Disney Studios and was replaced as Disney President by David Vogel. Vogel added the position of Hollywood Pictures in 1997, then was promoted in 1998 to head up all live action motion picture units as president of Buena Vista Motion Pictures Group, Pirates of the Caribbean launched a film series and made the ride into a franchise. After four Pirates sequels, the franchise took in more than $5.4 billion worldwide, so, the corporation was looking for addition of the ride adaptations. In 2010, Disney released Alice in Wonderland, an adaptation of the 1951 animated film of the name that became the second $1 billion-grossing film in the studios history. The film began a trend of fantasy genre films being green-lit. With sister units Marvel Studios and Lucasfilm successfully targeting the male market, with the success of Maleficent and Cinderella, the studio announced a whole series of live-action adaptations of animated films as being in early stages. The Jungle Book cemented this trend with a global near billion-dollar box office, some adaptations are sequels to existing adaptations, origin stories and prequels
Walt Disney Pictures
–
Walt Disney Pictures, Inc.
28.
Pixar
–
Pixar, also 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 also 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 also 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 also 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 then 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 later be sold to ShowBiz Pizza Place, a competitor, in 1985. Amongst the 38 remaining employees, there were also Malcolm Blanchard, David DiFrancesco, Ralph Guggenheim and Bill Reeves, Tom Duff, also an NYIT member, would later join Pixar after its formation
Pixar
–
Pixar's headquarters in Emeryville
Pixar
–
A Pixar Computer photographed at the
Computer History Museum with the 1986–1995 logo on it.
Pixar
–
John Lasseter appears with characters from
Up at the 2009
Venice Film Festival.
Pixar
–
Career
29.
Finding Dory
–
Finding Dory is a 2016 American 3D computer-animated comedy-drama adventure film produced by Pixar Animation Studios and released by Walt Disney Pictures. Directed by Andrew Stanton with co-direction by Angus MacLane, the screenplay was written by Stanton, Finding Dory focuses on the amnesiac fish Dory, who journeys to be reunited with her parents. The film premiered at the El Capitan Theatre in Los Angeles on June 8,2016, upon release, the film was a critical and commercial success, grossing over $1 billion worldwide, becoming the second Pixar film to cross this mark after 2010s Toy Story 3. The film set records, including the highest-grossing animated film opening of all time in North America. Dory, a Regal blue tang, gets separated from her parents as a child, as she grows up, Dory attempts to search for them, but gradually forgets them due to her short-term memory loss disability. In the flashback of the film, after accidentally running into Marlin. One year later, Dory has joined Marlin and Nemo on their reef, one day, Dory has a flashback and remembers that she has parents. She decides to look for them, but finds her memory problem an obstacle and she remembers that they lived at the Jewel of Morro Bay across the ocean in California. With the help of Crush, a sea turtle friend, they ride a water current to California, upon arrival, Dory accidentally awakens a squid, who immediately pursues them, almost devouring Nemo. Marlin berates Dory for endangering them and her feelings hurt, Dory travels to the surface to seek help and is captured by staff members from the nearby Marine Life Institute after getting entangled in six pack rings. Dory is placed in the section and tagged. There she meets a grouchy but well-meaning octopus named Hank, Dorys tag shows that she will be sent to an aquarium in Cleveland. Due to a traumatic ocean life, Hank wants to live in the aquarium instead of being released back into the ocean, Dory subsequently has flashbacks of life with her parents and struggles to recall details. She finally remembers how she was separated from her parents, she overheard her mother crying one night, left to retrieve a shell to cheer her up, Marlin and Nemo attempt to rescue Dory. With the help of two sea lions named Fluke and Rudder and a common loon named Becky, they manage to get into the institute. Other blue tangs tell them that Dorys parents escaped from the institute a time ago to search for her and never came back. Hank retrieves Dory from the tank, accidentally leaving Marlin and Nemo behind and he is then apprehended by one of the employees and unintentionally drops Dory into the drain, flushing her out to the ocean. While wandering aimlessly, she comes across a trail of shells, remembering that when she was young, her parents had set out a trail to help her find her way back home
Finding Dory
–
Teaser poster
30.
California
–
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
California
–
A forest of redwood trees in
Redwood National Park
California
–
Flag
California
–
Mount Shasta
California
–
Aerial view of the
California Central Valley
31.
East Australian Current
–
The East Australian Current is the southward western boundary current that is formed from the South Equatorial Current crossing the Coral Sea and reaching the eastern coast of Australia. At around 15° S near the Australian coast the SEC divides forming the flow of the EAC. It is the largest ocean current close to the shores of Australia, the EAC reaches a maximum velocity at 30° S where its flow can reach 90 cm/s. As it flows southward it splits from the coast at around 31° to 32° S, by the time it reaches 33° S it begins to undergo a southward meander while another portion of the transport turns back northward in a tight recirculation. At this location the EAC reaches its maximum transport of nearly 35 Sv, the majority of the EAC flow that does not recirculate will move eastward into the Tasman Front crossing the Tasman Sea just north of the cape of New Zealand. The Tasman Front transport is estimated at 13 Sv, the eastward movement of the EAC through the Tasman Front and reattaching to the coastline of New Zealand forms the East Auckland Current. The EAC also acts to transport tropical marine fauna to habitats in sub-tropical regions along the south east Australian coast, in the 2003 Disney/Pixar animated film Finding Nemo, the EAC is portrayed as a superhighway that fish and sea turtles use to travel down the east coast of Australia. The characters Marlin and Dory join a group of sea turtles in using the EAC to help them travel to Sydney Harbour, the basic premise of this storyline is correct. Every summer, thousands of fish are swept from the Great Barrier Reef to Sydney Harbour, ocean current Oceanic gyres Physical oceanography Image of the East Australian Current. Sea surface temperature and currents, New South Wales
East Australian Current
–
Thermal profile of the East Australian Current
East Australian Current
–
CSIRO NOAA polar orbiting satellites obtain the data generating sea surface temperature images. (Composite 15 day image showing the extension of the Leeuwin Current around Tasmania)
32.
International Standard Book Number
–
The International Standard Book Number is a unique numeric commercial book identifier. An ISBN is assigned to each edition and variation of a book, for example, an e-book, a paperback and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, the method of assigning an ISBN is nation-based and varies from country to country, often depending on how large the publishing industry is within a country. The initial ISBN configuration of recognition was generated in 1967 based upon the 9-digit Standard Book Numbering created in 1966, the 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108. Occasionally, a book may appear without a printed ISBN if it is printed privately or the author does not follow the usual ISBN procedure, however, this can be rectified later. Another identifier, the International Standard Serial Number, identifies periodical publications such as magazines, the ISBN configuration of recognition was generated in 1967 in the United Kingdom by David Whitaker and in 1968 in the US by Emery Koltay. The 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108, the United Kingdom continued to use the 9-digit SBN code until 1974. The ISO on-line facility only refers back to 1978, an SBN may be converted to an ISBN by prefixing the digit 0. For example, the edition of Mr. J. G. Reeder Returns, published by Hodder in 1965, has SBN340013818 -340 indicating the publisher,01381 their serial number. This can be converted to ISBN 0-340-01381-8, the check digit does not need to be re-calculated, since 1 January 2007, ISBNs have contained 13 digits, a format that is compatible with Bookland European Article Number EAN-13s. An ISBN is assigned to each edition and variation of a book, for example, an ebook, a paperback, and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, a 13-digit ISBN can be separated into its parts, and when this is done it is customary to separate the parts with hyphens or spaces. Separating the parts of a 10-digit ISBN is also done with either hyphens or spaces, figuring out how to correctly separate a given ISBN number is complicated, because most of the parts do not use a fixed number of digits. ISBN issuance is country-specific, in that ISBNs are issued by the ISBN registration agency that is responsible for country or territory regardless of the publication language. Some ISBN registration agencies are based in national libraries or within ministries of culture, in other cases, the ISBN registration service is provided by organisations such as bibliographic data providers that are not government funded. In Canada, ISBNs are issued at no cost with the purpose of encouraging Canadian culture. In the United Kingdom, United States, and some countries, where the service is provided by non-government-funded organisations. Australia, ISBNs are issued by the library services agency Thorpe-Bowker
International Standard Book Number
–
A 13-digit ISBN, 978-3-16-148410-0, as represented by an
EAN-13 bar code
33.
Seattle Times
–
The Seattle Times is a newspaper serving Seattle, Washington, United States. It is the daily newspaper in the state of Washington and has the largest Sunday circulation in the Pacific Northwest. It has been Seattles only major daily print newspaper since the demise of the version of the rival Seattle Post-Intelligencer in 2009. The Seattle Times originated as the Seattle Press-Times, a newspaper founded in 1891 with a daily circulation of 3,500. Renamed the Seattle Daily Times, it doubled its circulation within half a year, by 1915, circulation stood at 70,000. The newspaper moved to the Times Square Building at 5th Avenue and it built a new headquarters, the Seattle Times Building, north of Denny Way in 1930. The paper moved to its current headquarters at 1000 Denny Way in 2011, the Seattle Times switched from afternoon delivery to mornings on March 6,2000, citing that the move would help them avoid the fate of other defunct afternoon newspapers. This placed the Times in direct competition with its JOA partner, nine years later, the P-I became an online-only publication. The Times is one of the few remaining major city dailies in the United States independently operated and owned by a local family. The Seattle Times Company, while owning and operating the Times, the McClatchy Company owns 49.5 percent of voting common stock in the Seattle Times Company, formerly held by Knight Ridder until 2006. The Times reporting has received 10 Pulitzer Prizes, most recently for its news coverage of the 2014 landslide that killed 43 people in Oso. It has a reputation for its investigative journalism, in particular. In February 2002, The Seattle Times ran a subheadline American outshines Kwan, many Asian Americans felt insulted by the Times actions even after the newspaper apologized, because Michelle Kwan is also American. The newspapers management said the ads were aimed at demonstrating how effective advertising with The Times can be, the advertisements in favor of McKenna represent an $80,000 independent expenditure, making the newspaper the third largest contributor to his campaign. More than 100 staffers signed a letter of protest sent to Seattle Times Publisher Frank Blethen, the two papers maintained their own identities with separate news and editorial departments. The Times announced its intention to cancel the Joint Operating Agreement in 2003, hearst sued, arguing that a force majeure clause prevented the Times from claiming losses as reason to end the JOA when they result from extraordinary events. While a district judge ruled in Hearsts favor, the Times won on appeal, hearst continued to argue that the Times fabricated its loss in 2002. The two papers announced an end to their dispute on April 16,2007 and this arrangement JOA was terminated when the Post-Intelligencer ceased publication, its final printed edition was March 17,2009
Seattle Times
–
The July 4, 2006 front page of The Seattle Times
Seattle Times
–
The Seattle Times
Seattle Times
–
"Quarters of the news editor", one a group of four photos in the
brochure Seattle and the Orient (1900) collectively captioned "The Seattle Daily Times —Editorial Department"
34.
Ocean gyre
–
A gyre in oceanography is any large system of circulating ocean currents, particularly those involved with large wind movements. Gyres are caused by the Coriolis effect, planetary vorticity along with horizontal and vertical friction, determine the circulation patterns from the wind curl. The term gyre can be used to refer to any type of vortex in the air or the sea, even one that is man-made, atlantic Equatorial Current System Pacific Equatorial Current System Indian Monsoon Gyres The center of a subtropical gyre is a high pressure zone. Circulation around the high pressure is clockwise in the hemisphere and counterclockwise in the southern hemisphere. The high pressure in the center is due to the winds on the northern side of the gyre. These cause frictional surface currents towards the latitude at the center of the gyre and this build-up of water in the center creates flow towards the equator in the upper 1,000 to 2,000 m of the ocean, through rather complex dynamics. This flow is returned towards the pole in a western boundary current. Subpolar gyres form at high latitudes, circulation of surface wind and ocean water is counterclockwise in the Northern Hemisphere, around a low-pressure area, such as the persistent Aleutian Low and the Icelandic Low. Surface currents generally move outward from the center of the system and this drives the Ekman transport, which creates an upwelling of nutrient-rich water from the lower depths. Subpolar circulation in the southern hemisphere is dominated by the Antarctic Circumpolar Current, there are minor gyres in the Weddell Sea and the Ross Sea, the Weddell Gyre and Ross Gyre, which circulate in a clockwise direction. Recently stronger winds, especially the trade winds in the Pacific ocean have provided a mechanism for vertical heat distribution. The effect are changes in the currents, increasing the subtropical overturning. Depending on natural variability, during La Niña years around 30% more heat from the upper layer is transported into the deeper ocean. Several studies in recent years, found an increase in OHC of the deep and upper ocean regions. Because the Coriolis effect is strongest near the poles, water flowing eastward at high latitudes turns sooner and is short circuiting the gyre, at the equator the Coriolis effect is nonexistent and the water flows westward until it encounters a blocking continent. Westward boundary currents are faster and deeper than eastern boundary currents. Ocean gyres are known to collect pollutants
Ocean gyre
–
The five major ocean gyres
35.
East Greenland Current
–
The East Greenland Current is a cold, low salinity current that extends from Fram Strait to Cape Farewell. The current is located off the eastern coast of Greenland along the Greenland continental margin, the current cuts through the Nordic Seas and through the Denmark Strait. The EGC is composed of a mixture of three distinct water masses, the water masses are Polar Water, Atlantic Water, and Deep Water. The top 150 meters of the EGC is considered polar water and it is cold and low in salinity. The lowness in salinity has a lot to do with freshwater run off from sea ice melting, river runoff, and Pacific water flux and it is cold due to air-sea interactions while in the Arctic. Typical characteristics for the EGC Polar water are a temperature between 0 °C and –1.7 °C, and the salinity varies greatly from 30 psu to 34 psu at a 150-meter depth, the layer beneath the Polar Water is known as the Atlantic Water layer. It extends down to about 1000 m and this layer is defined as having relatively warm temperatures and saline waters. The temperatures are normally above 0 °C and have a salinity of 34 psu at 150 meters, the Atlantic water that is seen in the EGC comes from two different sources. The first source of Atlantic Water originates from westward directed Atlantic water in the West Spitsbergen Current and this current sends Atlantic water into the Fram Strait, and because it is more dense then the surface Polar water it sinks to an intermediate depth. The second source of AW in the EGC originates from recirculated AW in the Arctic and this is AW that has entered the Arctic via the North Atlantic and has been circulating in the Arctic and is now being pushed out of the Arctic via the EGC. The layer beneath the Atlantic Water is simply referred to as the Deep Water where the salinity and this level typically extends from 1000 meters to the bottom of the ocean. The temperatures in this level are normally below 0 °C. The deep water masses are recirculated within the Greenland Sea due to the Jan Mayen Fracture Zone, here, the deep water encounters the Jan Mayen Ridge and are deflected eastward towards the interior of the Greenland Sea Gyre. The upper layers are able to pass into the north of Iceland unhindered. It is important to note that these recirculated deep water masses in the Greenland Sea Gyre will be recirculated into the EGC once again in the future near Fram Strait, the general movement of the EGC is southward along the eastern Greenland continental margin. The currents are strong with annual averages of 6–12 cm/s in the upper part of the EGC with inter-annual maximums of 20–30 cm/s. It was estimated in 1991 by Hopkins et al. that the transport of water southward ranged from 2–32 sverdrups and that is quite a large variation that they attributed to the widely varying strength of the Atlantic Water flow at intermediate depths. More recent estimations of water transport in the top layers of the EGC is between 3 and 4 sverdrups, one of the most important aspects of the East Greenland Current is the amount of sea ice it exports into the North Atlantic Ocean
East Greenland Current
–
East Greenland Current
36.
Transpolar Drift Stream
–
The Transpolar Drift Stream is a major ocean current of the Arctic Ocean, transporting sea ice from the Laptev Sea and the East Siberian Sea towards Fram Strait. Drift experiments with ships like Fram or Tara showed that the drift takes between two and four years, in 1937, Pyotr Shirshov at the Soviet drift ice station North Pole-1 described this drift. The stream conveys water in two major routes to the northern Atlantic Ocean at a rate of about 1.5 miles per day. Primarily wind-driven, it flows roughly from the northern coast of Russia and Alaska and it has been cited as a major factor in the North Atlantic Oscillation and Arctic oscillation atmospheric changes. The drift typically takes one of two paths before exiting into the northern Atlantic Ocean, on decadal and longer timescales, the North Atlantic Oscillation and the Arctic Oscillation indices affect the flow pattern of the transpolar drift stream. During times of positive NAO and positive AO, there is a weak Arctic high, in this case, the drift flows from the Laptev Sea towards the Beaufort Sea before exiting the Arctic Ocean through the Fram Strait. Conversely, during periods of NAO- and AO-, there is a strong Arctic high, in this phase, the drift flows directly from the Laptev Sea through the Fram Strait. Drift Station, Arctic Outposts of Superpower Science
Transpolar Drift Stream
–
Transpolar Drift and
Beaufort Gyre are major
ocean currents within the
Arctic Ocean.
37.
Brazil Current
–
The Brazil Current is a warm water current that flows south along the Brazilian south coast to the mouth of the Río de la Plata. This current is caused by diversion of a portion of the Atlantic South Equatorial Current from where that current meets the South American continent and it is a western boundary current like the Gulf Stream, and is indeed its southern counterpart, however, it is considerably shallower and weaker. It flows south from the equator to the west wind drift and it joins the Falkland Current at the Argentine Sea, making it a temperate sea
Brazil Current
–
Brazil Current in a map of the Atlantic Ocean
38.
Caribbean Current
–
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
Caribbean Current
–
This article needs additional citations for
verification. Please help improve this article by
adding citations to reliable sources. Unsourced material may be challenged and removed. (February 2013)
39.
Gulf Stream
–
The process of western intensification causes the Gulf Stream to be a northward accelerating current off the east coast of North America. At about 40°0′N 30°0′W, it splits in two, with the stream, the North Atlantic Drift, crossing to Northern Europe and the southern stream. The Gulf Stream influences the climate of the east coast of North America from Florida to Newfoundland, and it is part of the North Atlantic Gyre. Its presence has led to the development of strong cyclones of all types, the Gulf Stream is also a significant potential source of renewable power generation. The Gulf Stream may be slowing down as a result of climate change, the Gulf Stream is typically 100 kilometres wide and 800 metres to 1,200 metres deep. The current velocity is fastest near the surface, with the maximum speed typically about 2.5 metres per second. European discovery of the Gulf Stream dates to the 1512 expedition of Juan Ponce de León and its existence was also known to Peter Martyr dAnghiera. Benjamin Franklin became interested in the North Atlantic Ocean circulation patterns, Franklin asked Timothy Folger, his cousin twice removed, a Nantucket Island whaling captain, for an answer. Franklin worked with Folger and other experienced ship captains, learning enough to chart the Gulf Stream and he offered this information to Anthony Todd, secretary of the British Post Office, but it was ignored by British sea captains. Franklins Gulf Stream chart was published in 1770 in England, where it was mostly ignored, subsequent versions were printed in France in 1778 and the U. S. in 1786. The Gulf Stream proper is a current, driven largely by wind stress. The North Atlantic Drift, in contrast, is largely thermohaline circulation–driven, in 1958 the oceanographer Henry Stommel noted that very little water from the Gulf of Mexico is actually in the Stream. By carrying warm water northeast across the Atlantic, it makes Western, a river of sea water, called the Atlantic North Equatorial Current, flows westward off the coast of Central Africa. When this current interacts with the northeastern coast of South America, one passes into the Caribbean Sea, while a second, the Antilles Current, flows north and east of the West Indies. These two branches north of the Straits of Florida. 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 across the north Atlantic Ocean. The resulting Sverdrup transport is equatorward, the conservation of potential vorticity also causes bends along the Gulf Stream, which occasionally break off due to a shift in the Gulf Streams position, forming separate warm and cold eddies. This overall process, known as western intensification, causes currents on the boundary of an ocean basin, such as the Gulf Stream
Gulf Stream
–
Surface temperature in the western North Atlantic. North America is black and dark blue (cold), the Gulf Stream red (warm). Source:
NASA
Gulf Stream
–
Benjamin Franklin 's map of the Gulf Stream
Gulf Stream
–
Evolution of the Gulf Stream to the west of Ireland continuing as the
North Atlantic Current
Gulf Stream
–
Hurricane Alex formed and moved along the axis of the Gulf Stream in 2004.
40.
Labrador Current
–
It is a continuation of the West Greenland Current and the Baffin Island Current. It meets the warm Gulf Stream at the Grand Banks southeast of Newfoundland, the combination of these two currents produces heavy fogs and has also created one of the richest fishing grounds in the world. In spring and early summer, this current transports icebergs from the glaciers of Greenland southwards into the shipping lanes. The waters of the Labrador Current have an effect on the Canadian Atlantic provinces. The transport of the Labrador Current is believed to contain a large barotropic component, early estimates indicated that the current may be 30% stronger than geostrophic calculations indicated as a result of a significant barotropic flow component. Greenberg and Petrie calculated a total transport of 7.6 sverdrup, the geostrophic transport was calculated to be just 4.1 Sv. With a 30% increase the transport is only 5.3 Sv so, speeds for the Labrador Current are about 0. 3–0.5 m/s along the shelf edge. Current speeds of 0. 3–0.5 m/s were found by Reynaud et al. for the Labrador Current. Including the barotropic component, they estimate a value of 3 Sv for the continental shelf branch of the Labrador Current and 16 Sv transport for the branch of the Labrador Current. Within the Flemish Pass, Petrie and Isenor report that the width of the Labrador Current is reduced to 50 km with a speed of 0.25 m/s which they believe is actually 0.30 m/s. The Labrador Current has a tendency to go farther south and/or east than normal. This can produce hazardous shipping conditions as it can carry icebergs into an area of the Atlantic where they are not usually found, the current has been known to transport icebergs as far south as Bermuda and as far east as the Azores. After the sinking of the RMS Titanic in 1912, the International Ice Patrol was set up to track icebergs, surface Currents in the Atlantic Ocean
Labrador Current
–
Photo of
eddies in the Labrador Current
Labrador Current
–
Map of Labrador Current
41.
Loop Current
–
Mesh analysis is a method that is used to solve planar circuits for the currents at any place in the electrical circuit. Planar circuits are circuits that can be drawn on a surface with no wires crossing each other. A more general technique, called loop analysis can be applied to any circuit, mesh analysis and loop analysis both make use of Kirchhoff’s voltage law to arrive at a set of equations guaranteed to be solvable if the circuit has a solution. Mesh analysis is easier to use when the circuit is planar. Mesh analysis works by arbitrarily assigning mesh currents in the essential meshes, an essential mesh is a loop in the circuit that does not contain any other loop. Figure 1 labels the essential meshes with one, two, and three, a mesh current is a current that loops around the essential mesh and the equations are set solved in terms of them. A mesh current may not correspond to any physically flowing current and it is usual practice to have all the mesh currents loop in the same direction. This helps prevent errors when writing out the equations, the convention is to have all the mesh currents looping in a clockwise direction. Figure 2 shows the circuit from Figure 1 with the mesh currents labeled. Solving for mesh currents instead of directly applying Kirchhoffs current law and this is because there are fewer mesh currents than there are physical branch currents. In figure 2 for example, there are six branch currents and these equations are the sum of the voltage drops in a complete loop of the mesh current. For problems more general than those including current and voltage sources, the following is the same circuit from above with the equations needed to solve for all the currents in the circuit. There are two cases in mesh current, currents containing a supermesh and currents containing dependent sources. A supermesh occurs when a current source is contained between two essential meshes, the circuit is first treated as if the current source is not there. This leads to one equation that incorporates two mesh currents, once this equation is formed, an equation is needed that relates the two mesh currents with the current source. This will be an equation where the current source is equal to one of the mesh currents minus the other, the following is a simple example of dealing with a supermesh. When a dependent source is contained within an essential mesh, the dependent source should be treated like an independent source, after the mesh equation is formed, a dependent source equation is needed. This equation is called a constraint equation
Loop Current
42.
North Atlantic Current
–
The North Atlantic Current, also known as North Atlantic Drift and North Atlantic Sea Movement, is a powerful warm western boundary current that extends the Gulf Stream north-eastward. The NAC originates from where the Gulf Stream turns north at the Southeast Newfoundland Rise, the NAC flows northward east of the Grand Banks, from 40°N to 51°N, before turning sharply east to cross the Atlantic. It transports more warm water to northern latitudes than any other boundary current. It reaches speeds of 2 knots near the North American coast, directed by topography, the NAC meanders heavily but, in contrast to the meanders of the Gulf Stream, the NAC meanders remain stable without breaking off into eddies. The colder parts of the Gulf Stream turn northward near the tail of the Grand Banks at 50°W where the Azores Current branches off to flow south of the Azores, from there the NAC flow north-eastward east of the Flemish Cap. Approaching the Mid-Atlantic Ridge, it turns eastward and becomes much broader. It then splits into a colder, north-eastern branch and an eastern branch. West of Continental Europe, it splits into two major branches, one branch goes southeast, later to become the Canary Current as it passes northwest Africa and turns southwest. The other major branch continues north along the coast of Northwestern Europe, other branches include the Irminger Current and the Norwegian Current. The North Atlantic Current, together with the Gulf Stream, have a reputation for having a considerable warming influence on European climate. The principal cause for differences in climate between North America and Europe is, however, winds rather than ocean currents. North Atlantic Oscillation Ocean gyre Physical oceanography Notes Sources The North Atlantic Current, elizabeth Rowe, Arthur J. Mariano, Edward H. Ryan, The Cooperative Institute for Marine and Atmospheric Studies
North Atlantic Current
–
Schematic of the world's ocean currents
43.
Portugal Current
–
The Portugal Current is a weak warm water current that flows south-easterly towards the coast of Portugal. The current results from the movement of water east caused by the North Atlantic Drift, bischof, Barbie, Arthur J. Mariano, Edward H. Ryan. University of Miami Rosenstiel School of Marine and Atmospheric Science
Portugal Current
–
North Atlantic currents
44.
West Spitsbergen Current
–
The West Spitsbergen Current is a warm, salty current that runs poleward just west of Spitsbergen, in the Arctic Ocean. The WSC branches off the Norwegian Atlantic Current in the Norwegian Sea, the WSC is of importance because it drives warm and salty Atlantic Water into the interior Arctic. The warm and salty WSC flows north through the side of Fram Strait. The EGC is characterized by being cold and low in salinity. Thus, the EGC combined with the warm WSC makes the Fram Strait the northernmost ocean area having ice-free conditions throughout the year in all of the global ocean, the WSC has a unique structure as it flows poleward off the western coast of Spitsbergen. It is easiest to discuss horizontal movements and vertical movements of the WSC, specifically, it tends to follow along steep continental shelves. The current is quite narrow and strong, having a width of roughly 100 kilometers, at about 80° North latitude the WSC splits into two different sections, the Svalbard branch and the Yermak Branch. The Yermak Branch moves northwesterly till about 81°N, and then it moves directly westward, the Return Atlantic Current is directly east of the East Greenland Current. There is a current that splits off from the Yermak Branch and this current is not well understood in the literature, and thus more information is needed. It is believed this current loops back into the Svalbard Branch further along in its track eastward, after the WSC splits off from the Norwegian Atlantic Current it begins to enter very cold atmospheric conditions. This is one element of the formation of the Lower Arctic Intermediate Water, as the current continues to move northward and reaches the continental shelf of western Svalbard it begins to encounter sea-ice. The sea-ice melts due to the warmth of the WSC, winds mix the freshwater and the warm salty water of the WSC mix, creating some Arctic Surface Water. This Arctic Surface Water is now less dense than the Atlantic Water in the WSC, at this point the WSC is still relatively warm and very saline. Thus, this allows the Atlantic Water in the WSC to be isolated from the surface waters. After the current splits into the Svalbard Branch and the Yermak Branch, however, in the Yermak Branch the WSC is not able to penetrate deep inside the Arctic Ocean because the zone it enters has very strong tidal mixing. This allows the Atlantic Water to mix with the Polar Waters, creating more of a mixture of relatively warm. This extends down to about 300 meters which is recognized as the depth of the Return Atlantic Current. For the Svalbard Branch, the Atlantic Water core of the WSC continues to sink as it more and more freshwater on its eastern route
West Spitsbergen Current
–
The West Spitsbergen Current transport relative warm and saline water into the
Arctic Ocean.
45.
Agulhas Current
–
The Agulhas Current /əˈɡʌləs/ is the western boundary current of the southwest Indian Ocean. It flows down the east coast of Africa from 27°S to 40°S and it is narrow, swift and strong. The sources of the Agulhas Current are the East Madagascar Current, the Mozambique Current, the net transport of the Agulhas Current is estimated as 100 Sv. The flow of the Agulhas Current is directed by the topography, the current follows the continental shelf from Maputo to the tip of the Agulhas Bank. Here the momentum of the current overcomes the vorticity balance holding the current to the topography, the current reaches its maximum transport near the Agulhas Bank where it ranges between 95-136 Sv. The core of the current is defined as where the surface velocities reaches 100 cm/s, the mean peak speed is 136 cm/s, but the current can reach 245 cm/s. As the Agulhas Current flows south along the African east coast, it tends to bulge inshore frequently and these bulges are occasionally followed by a much larger offshore bulge, known as Natal pulses. Natal pulses move along the coast at 20 km per day, an ACM can bulge up to 20 km and a NP up to 120 km from the currents mean position. The AC passes 34 km offshore and an ACM can reach 123 km offshore, when the AC meanders, its width broadens from 88 km to 125 km and its velocity weakens from 208 cm/s to 136 cm/s. An ACM induces a strong inshore counter-current, large-scale cyclonic meanders known as Natal pulses are formed as the Agulhas Current reaches the continental shelf on the South African east-coast. As these pulses moves along the coast on the Agulhas Bank, such a ring shedding can be triggered by a Natal pulse alone, but sometimes meanders on the Agulhas Return Current merge to contribute to the shedding of an Agulhas ring. This water becomes the Agulhas Return Current, rejoining the Indian Ocean Gyre and it is estimated that up to 85 Sv of the net transport is returned to the Indian Ocean through the retroflection. The remaining water is transported into the South Atlantic Gyre in the Agulhas Leakage, along with direct branch currents, this leakage takes place in surface water filaments, and Agulhas Eddies. It is estimated that as much as 15 Sv of Indian Ocean water is leaked directly into the South Atlantic,10 Sv of this is relatively warm, salty thermocline water, with the remaining 5 Sv being cold, low salinity Antarctic Intermediate Water. Since Indian Ocean water is warmer and saltier than South Atlantic water. This heat flux is believed to contribute to the rate of evaporation in the South Atlantic. It should be noted that an amount of the Agulhas Leakage joins the North Brazil Current. Surface water filaments are estimated to account for up to 13% of the total salt transport from the Agulhas Current into the Benguela Current, due to surface dissipation, these filaments are not believed to significantly contribute to inter-basin heat flux
Agulhas Current
46.
Agulhas Return Current
–
The Agulhas Return Current is an ocean current in the South Indian Ocean. The ARC contributes to the exchange between oceans by forming a link between the South Atlantic Current and the South Indian Ocean Current. It can reach velocities of up to 4 knots and is popular among participants in trans-oceanic sailing races. The Agulhas Current follows the continental shelf of the African east-coast, pass through the Agulhas Passage until it leaves the Agulhas Bank and reaches the Agulhas Basin south of South Africa. From there it retroflects almost completely back into the south Indian Ocean as the ARC, the water mass loses a lot of heat at the Agulhas Retroflection, up to 200 W/m3, while evaporation and precipitation change the composition of the upper layers. The ARC, therefore, has another composition than the Agulhas Current proper and it also loses velocity from 110–75 cm/s and volume transport from 70 to 54 million m³/s. Furthermore, all traces of Indian Tropical Surface Water are gone, having left the retroflection, the ARC meanders east between 36°S and 41°S. These meanders were described as Rossby waves in 1970 and are known to shed cold eddies equatorward, the ARC makes a large, quasi-permanent northward meander around the Agulhas Plateau after which it loses more velocity and volume by leakage into the South Indian subtropical gyre. Over the Crozet Basin the last remnants of the ARC are gone, as it enters the Crozet Basin at 53°E, the transport of the ARC is 35 Sv, most of which is recirculated northward before reaching the Kerguelen-Amsterdam Passage. The current east of the Crozet Basin, at 66°E-70°E, is called the South Indian Ocean Current and lacks the distinctive features of the ARC
Agulhas Return Current
–
The Agulhas Return Current (ARC) meanders east from the southern tip of Africa
47.
Indonesian Throughflow
–
From the Banda Sea the ITF exits Timor, Ombai, and Lombok passages. The location and topography of the channels that make up the ITF are shown in the Figure, Lombok Strait is 300m deep and roughly 35 km wide and the currents vary between 0.286 m/s eastward to 0.67 m/s westward and average 0.25 m/s westward. Currents in Ombai vary between 0.12 m/s eastward to 0.16 m/s westward, averaging 0.11 m/s westward and are funneled within the 1250m deep and 35 km wide passage. Timor passage, which is 1890 m deep by 160 km wide, is the widest of the exit pathways, flow in through Makassar and Lifamatola sums to 12.7 Sv. Total outflow transport corresponds to 15.0 Sv and is made up of Lombok, Ombai, heat Transport of the Indonesian Throughflow is 1.087 PW. Circulation and transport within the Indonesian Seas varies along with large-scale monsoon flow, another way to think about it is that downwelling on the Indian Ocean side increases sea level and so reduces the normal Pacific-to-Indian pressure head reducing the flow. Global-scale, ocean waves such as equatorial/coastal Kelvin and Rossby waves drive interannual variation of the ITF with an amplitude of roughly +/-3 Sv, upwelling associated with Rossby waves on the Pacific side reduces the Pacific-to-Indian pressure gradient and reduces the ITF. Interannual variability of Indian Ocean westerlies act in the manner as the seasonal equatorial Kelvin waves to reduce the normal westward ITF flow as well. When the Indonesian Throughflow enters the Indian Ocean it is advected towards Africa within the Indian South Equatorial Current, there it eventually exits the Indian Ocean with the Agulhas Current around South Africa into the Atlantic Ocean. So the Indonesian Throughflow transports a significant amount of Pacific Ocean heat into the southwest Indian Ocean, Ocean gyre Throughflow The Indonesian Throughflow at whoi. edu
Indonesian Throughflow
–
Schematic of the ITF. Values of the flow and the major passages are indicated by red. Water enters the ITF from the western Pacific and exits into the Indian Ocean.
48.
Leeuwin Current
–
The Leeuwin Current is a warm ocean current which flows southwards near the western coast of Australia. It rounds Cape Leeuwin to enter the south of Australia where its influence extends as far as Tasmania. Its strength varies through the year, it is weakest during the months from November to March when the winds tend to blow strongly from the south west northwards. The greatest flow is in the autumn and winter when the winds are weakest. Evaporation from the Leeuwin current during this period contributes greatly to the rainfall in the southwest region of Western Australia. Typically the Leeuwin Currents speed and its eddies are about 1 knot, although speeds of 2 knots are common, and the highest speed ever recorded by a drifting satellite-tracked buoy was 3.5 knots. The Leeuwin Current is shallow for a current system, by global standards, being about 300 m deep. Because of the Leeuwin Current, the shelf waters of Western Australia are warmer in winter and cooler in summer than the corresponding regions off the other continents. The ‘core’ of the Leeuwin Current can generally be detected as a peak in the temperature with a strong temperature decrease further offshore. The surface temperature difference across the Current is about 1°C at North West Cape, 2° to 3° at Fremantle, the current frequently breaks out to sea, forming both clockwise and anti-clockwise eddies. The existence of the current was first suggested by William Saville-Kent in 1897, Saville-Kent noted the presence of warm tropical water offshore in the Houtman Abrolhos, making the water there in winter much warmer than inshore at the adjacent coast. The existence of the current was confirmed over the years, but not characterised and named until Cresswell, Western fisheries magazine, Winter 2000, p. 47-49 Ocean current Oceanic gyres Physical oceanography West Australian Current Climate change threatening the Southern Ocean. CSIRO Marine Research Rottnest Island context
Leeuwin Current
–
CSIRO NOAA polar orbiting satellites obtain the data generating sea surface temperature images. (Composite 15 day image showing the extension of the Leeuwin Current around Tasmania)
Leeuwin Current
–
Ocean Currents surrounding Australia. The Leeuwin Current can be seen off the Western Australian Coast
Leeuwin Current
–
Data from two satellite instruments is used in constructing this image of the Leeuwin Current. Sea surface temperature information comes from the US NOAA 14 satellite while the surface current velocity is derived from sea level measurements made by the satellite-borne altimeter. Sea level data from the US/French Topex/Poseidon and European ERS altimeters are combined
49.
Mozambique Current
–
The classical definition of the Mozambique Current is that it is a strong, steady, western boundary current. Modern research has challenged that assumption, and indicates that rather than a western boundary current. Direct evidence for these eddies has been found in satellite altimetry data, ship borne surveys, nonetheless, it is impossible to rule out the possibility that the Mozambique Current may appear intermittently, for short durations. Indeed, numerical simulations in the Mozambique Channel show the appearance of a current on the Mozambican Coast. Mozambique Channel Eddies are large, warm, anti-cyclonic eddies that propagate southwards in the Mozambique Channel and these eddies may have diameters of up to 300 km, and maximum swirl velocities of nearly 1 m/s. The exact causal mechanism, and location of the formation is still debated. The frequency of eddy occurrence reduces from around seven per year in the north of the Channel, once the eddies exit the Mozambique Channel, they contribute to the variability of the Agulhas Current, including the generation of the Natal Pulse, and Agulhas Rings
Mozambique Current
–
visualisation of ocean currents
50.
West Australian Current
–
The West Australian Current, is a cool surface current of the Southern Ocean and Southern Indian Ocean. It starts as the Southern Indian Ocean Current, a part of the larger Antarctic Circumpolar Current, as the current approaches Western Australia, it turns north, parallel to the western coast of Australia, and becomes the West Australian Current. The current is mainly seasonal, being weaker in winter and stronger in summer and these 3 currents together contribute greatly to the rainfall and climate in the southwest region of Western Australia. Ocean current Oceanic gyres Physical oceanography
West Australian Current
–
Ocean Currents surrounding Australia. The West Australian Current is located where the
Leeuwin Current is labeled and flows in the opposite direction to the Leeuwin Current
51.
Kuroshio Current
–
The Kuroshio is a north-flowing ocean current on the west side of the North Pacific Ocean. It is similar to the Gulf Stream in the North Atlantic and is part of the North Pacific ocean gyre, like the Gulf stream, it is a strong western boundary current. It begins off the east coast of Luzon, Philippines, Taiwan and flows northeastward past Japan and it is analogous to the Gulf Stream in the Atlantic Ocean, transporting warm, tropical water northward toward the polar region. It is sometimes known as the Black Stream — the English translation of kuroshio, the path of Kuroshio south of Japan is reported every day. Its counterparts are the North Pacific Current to the north, the California Current to the east, the warm waters of the Kuroshio Current sustain the coral reefs of Japan, the northernmost coral reefs in the world. The branch into the Sea of Japan is called Tsushima Current, western boundary currents transport organisms long distances rapidly and a variety of commercially important marine organisms migrate in these currents in the course of completing their lives. Subtropical gyres occupy a fraction of the worlds ocean and are more productive than originally thought. In addition, their fixation of carbon dioxide is an important factor in the budget for carbon dioxide in the atmosphere. Satellite images of the Kuroshio Current illustrate how the current path meanders, eddies retain their unique form for several months and have their own biological characteristics that depend on where they form. The eddies size and strength decline with distance from major ocean currents, the amount of energy decreases from the rings associated with the major currents and down to eddies remote from those currents. Cyclonic eddies have the potential to cause upwelling that would affect the global primary-production budget, upwelling brings cold, nutrient-rich water to the surface resulting in an increase in productivity. The biological consequences for fish populations that inhabit the shelf are quite large. The Kuroshio is a warm current—24 °C annual average sea-surface temperature—about 100 kilometres wide, the coastal areas are highly productive and the maximum chlorophyll value is found around 100 metres depth. There are indications that eddies contribute to the preservation and survival of fish larvae transported by the Kuroshio, plankton biomass fluctuates yearly and is typically highest in the eddy area of the Kuroshio’s edge. Warm-core rings are not known for having high productivity, however, the biology of the warm-core rings from the Kuroshio Current show results of productivity equally distributed throughout for a couple of reasons. One is upwelling at the periphery, the other is the convective mixing caused by the cooling of water as the ring moves north of the current. The thermostad is the mixed layer that has discrete boundaries. Within this layer, nutrient-rich water is brought to the surface, there are many complex interactions with the warm-core ring and thus lifetime productivity is not very different from the surrounding shelf water
Kuroshio Current
–
The
Oyashio Current colliding with the Kuroshio Current near
Hokkaido. When two currents collide, they create
eddies.
Phytoplankton growing in the surface waters become concentrated along the boundaries of these eddies, tracing out the motions of the water.
Kuroshio Current
–
The Kuroshio Current is the west side of the clockwise North Pacific
ocean gyre
52.
North Pacific Current
–
The North Pacific Current is a slow warm water current that flows west-to-east between 40 and 50 degrees north in the Pacific Ocean. The current forms the part of the North Pacific Subpolar Gyre. The North Pacific Current forms the part of the North Pacific Subtropical Gyre. In the eastern North Pacific near southern British Columbia, it splits into the southward California Current, flowing easterly from the island of Honshu, Japan, the North Pacific Current covers over 20° of longitude. According to the Great Soviet Encyclopedia the NPC is often considered to be a part of the Kuroshio current, the current covers a large area bringing the warmer latitudinal waters up into the sub-polar latitudes causing a temperature differential of nearly 48.2 F°. The average sea temperature along the NPC can range in the winter from 45-61°F. Along the NPC path from west to east the current begins to slow in velocity to around 0.1 m/s, as the NPC approaches the Northwestern coast of North America it divides into two currents the Alaska and California current. The Gulf of Alaska and the California Current receive different volumes and this division of water flow is known as bifurcation The Gulf of Alaska receives about 60% of the water from the NPC and the California Current receives approximately the other 40% of the NPC water. These volumes do fluctuate, however the result in increased volumes and velocities of the NPC water entering into these currents. The NPC is the Northern boundary current that forms the North Pacific Subtropical Gyre, as a shoot off of the Kuroshio the NPC slows during its westward flow to the Americas. However, the NPC maintains enough momentum to bound the northern edge of the gyre, the North Pacific Gyre is estimated to be 7-9 million square miles. Debris from the ocean can become isolated into the center of the gyres as well as being distributed along the perimeter, debris from the Japanese earthquake of 2011 has been found on the shores of Canada, Alaska, and Washington. Quick Bulletin of Ocean Conditions around Japan
North Pacific Current
–
The North Pacific Current.
53.
Oyashio Current
–
Oyashio, also known as Oya Siwo, Okhotsk or the Kurile current, is a cold subarctic ocean current that flows south and circulates counterclockwise in the western North Pacific Ocean. It collides with the Kuroshio Current off the shore of Japan to form the North Pacific Current. The nutrient-rich Oyashio is named for its role as the parent that provides for. However, the Oyashio Current also causes Vladivostok to be the most equatorward port to seasonally freeze, nonetheless, this has relatively little effect on the fish yield through the Sea of Okhotsk, because the large tides mean freezing does not occur so easily. During glacial periods, when sea level exposed the Bering land bridge. The level of cooling with the onset of glacial conditions was much less than in areas of the Earth at similar latitudes. Ocean current Oceanic gyres Physical oceanography Japanese destroyer Oyashio, the Imperial Japanese Navy destroyer named after the current, taylor and Francis, ISBN 90-5410-706-5, pp 367–8. Regional Definition page for the Oyashio Current, UNEP Global International Waters Assessment, accessed 2 July 2010
Oyashio Current
–
The Oyashio Current colliding with the
Kuroshio Current near
Hokkaido. When two currents collide, they create
eddies.
Phytoplankton growing in the surface waters become concentrated along the boundaries of these eddies, tracing out the motions of the water.
54.
Antarctic Circumpolar Current
–
The Antarctic Circumpolar Current is an ocean current that flows clockwise from west to east around Antarctica. An alternative name for the ACC is the West Wind Drift, the ACC is the dominant circulation feature of the Southern Ocean and has a mean transport of 100-150 Sverdrups, making it the largest ocean current. More recent research puts this number at over 173 Sv. The current is due to the lack of any landmass connecting with Antarctica. Associated with the Circumpolar Current is the Antarctic Convergence, where the cold Antarctic waters meet the waters of the subantarctic. These nurture high levels of phytoplankton with associated copepods and krill, and resultant foodchains supporting fish, whales, seals, penguins, albatrosses and a wealth of other species. The clipper route, which is the fastest sailing route around the world, the current creates the Ross and Weddell gyres. The ACC connects the Atlantic, Pacific and Indian Oceans, the current is strongly constrained by landform and bathymetric features. Passing through the Indian Ocean, the current first retroflects the Agulhas Current to form the Agulhas Return Current before it is split by the Kerguelen Plateau, deflection is also seen as it passes over the mid-ocean ridge in the Southeast Pacific. The current is accompanied by three fronts, the Subantarctic front, the Polar front, and the Southern ACC front, furthermore, the waters of the Southern Ocean are separated from the warmer and saltier subtropical waters by the subtropical front. The northern boundary of the ACC is defined by the edge of the SAF. Still further south lies the PF, which is marked by a transition to cold, relatively fresh. Here a temperature minimum is allowed by salinity dominating density stratification, further south still is the SACC, which is determined as the southernmost extent of Circumpolar Deep Water. This water mass flows along the shelfbreak of the western Antarctic Peninsula and thus marks the most southerly water flowing through Drake Passage, the bulk of the transport is carried in the middle two fronts. The total transport of the ACC at Drake Passage is estimated to be around 135 Sv, or about 135 times the transport of all the worlds rivers combined. There is a small addition of flow in the Indian Ocean, with the transport south of Tasmania reaching around 147 Sv. The circumpolar current is driven by the westerly winds in the latitudes of the Southern Ocean. In latitudes where there are continents, winds blowing on light surface water can pile up light water against these continents
Antarctic Circumpolar Current
–
The Antarctic Circumpolar Current is the strongest current system in the world oceans and the only ocean current linking all major oceans: the Atlantic, Indian and Pacific Oceans. Seawater density fronts after Orsi, Whitworth & Nowlin 1995.
Antarctic Circumpolar Current
–
The
Falkland Current transports nutrient-rich cold waters from the ACC north towards the
Brazil–Malvinas Confluence. Phytoplankton chlorophyll concentration are shown in blue (lower concentrations) and yellow (higher concentrations).
55.
Indian Ocean Gyre
–
The Indian Ocean gyre, located in the Indian Ocean, is one of the five major oceanic gyres, large systems of rotating ocean currents, which together form the backbone of the global conveyer belt. The Indian Ocean gyre is composed of two currents, the South Equatorial Current, and the West Australian Current. Normally moving counter-clockwise, in the winter the Indian Ocean gyre reverses direction due to the winds of the South Asian Monsoon. In the summer, the land is warmer than the ocean, however, during the winter, these temperatures reverse, making the winds blow from the land to the ocean. Because most of the air pressure gradient is retained behind the Tibetan plateau, air pressure gradients over the Indian Ocean and this results in winds of moderate strength, due to the protection from the full force winds blowing off the Mongolian high pressure region. Because of these moderate, dry winds, the Winter Monsoon season in the Indian Ocean region is the dry season for most of Southern Asia. Due to this seasonal wind cycle, the currents of the Indian Ocean, like the other gyres, it contains a garbage patch. A garbage patch is a region of marine debris within the water column that circulate the gyre constantly. The Indian Ocean’s garbage patch covers an area, at least five million square kilometers. As garbage patches such as these circulate for long periods of time, in the Indian Ocean gyre, the garbage patch has been more of a mystery. Having just been discovered in 2010, it is still under research and it is known, however, that like most garbage patches, it is very fluid, and changes with the seasons, making its location difficult to pinpoint. It seems to circulate with the Indian Ocean gyre, from the Australian side to the African side, down the African coast, and then back to Australia. According to the team who discovered the garbage patch, the rotation of the gyre’s garbage patch takes about six years, until it reaches the center of the gyre
Indian Ocean Gyre
–
The Indian Ocean Gyre
56.
North Atlantic Gyre
–
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
North Atlantic Gyre
–
View of the currents surrounding the gyre.
57.
South Atlantic Gyre
–
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
South Atlantic Gyre
–
A
tristan thrush on
Inaccessible Island, strewn with oceanic trash.
South Atlantic Gyre
–
The South Atlantic Gyre on 1943 map.
58.
South Pacific Gyre
–
The center of the South Pacific Gyre is the site on Earth farthest from any continents and productive ocean regions and is regarded as Earth’s largest oceanic desert. Earth’s trade winds and Coriolis force cause the ocean currents in South Pacific Ocean to circulate counter clockwise, the low levels of biogenic and eolian deposition cause sediments to accumulate on the ocean floor very slowly. In the center of the South Pacific Gyre, the rate is 0.1 to 1 m per million years. The sediment thickness ranges from 1 to 70m, with thinner sediments occurring closer to the center of the Gyre, the low flux of particles to the South Pacific Gyre cause the water there to be the clearest seawater in the world. Beneath the seafloor, the sediments and surrounding porewaters contain an unusual subseafloor biosphere. Despite extremely low amounts of buried organic material, microbes live throughout the sediment column. Average cell abundances and net rates of respiration are a few orders of magnitude lower than any other subseafloor biosphere previously studied, the South Pacific Gyre subseafloor community is also unusual because it contains oxygen throughout the entire sediment column. In other subseafloor biospheres, microbial respiration will break down organic material, however, in the South Pacific Gyre the low levels of organic material, the low rates of respiration, and the thin sediments allow the porewater to be oxygenated throughout the entire sediment column. Satellite data images show that some areas in the gyre are greener than the clear blue water. However, the assumption that greener ocean water contains more phytoplankton is not always true. Even though the South Pacific Gyre contains these patches of green water, instead, some studies hypothesize that these green patches are a result of the accumulated waste of marine life. The optical properties of the South Pacific Gyre remain largely unexplored
South Pacific Gyre
–
The South Pacific Gyre.
59.
Beaufort Gyre
–
The Beaufort Gyre is a wind-driven ocean current located in the Arctic Ocean polar region. The gyre contains both ice and water and it accumulates fresh water by the process of melting the ice floating on the surface of the water. Conditions in the Arctic have favored sea ice loss in recent years during the Northern Hemisphere summers. A reason for the existence of this link was proposed, “. delayed winter ice formation allows for efficient coupling between the ocean and wind forcing. ”These dynamical mechanisms are observed in the spin-up and circulation of the Beaufort Gyre. Housed in the part of the Arctic Ocean is the Beaufort Gyre. In recent years, this increasing freshwater content has been the point of many studies. The majority of the Arctic’s freshwater content resides in the Beaufort Gyre, although biased toward the Northern Hemisphere summer months, observations from submarines, ships, and stations on drifting ice suggest that the gyre has been expanding over the past two decades. Researchers have employed coupled sea-ice-ocean general circulation models in order to analyze these observations. Model results show that Ekman transport plays an role in the variability of freshwater in the gyre. The prevailing rotational direction of the Beaufort Gyre is clockwise, following the wind circulation of the Polar High. Coriolis veers moving objects to the right in the northern hemisphere and this is why anything floating, including fresher water tends to move toward the centre of the system. Indeed, there is a bulge in the centre of the Beaufort gyre when it is rotating in its predominant clockwise direction. This could well bring up the saltier, slightly warmer Atlantic water which lies under the floating, variations in the Ekman transport change the sea surface height and depth of the halocline, resulting in Ekman pumping. Giles et al. conclude that the variability in freshwater content varies with wind stress curl, the seasonal cycle of freshwater content does not only concern mechanical processes, but thermal processes as well. The Beaufort Gyre contains a volume of 800 km^3 of frozen freshwater, or sea ice. The maximum in freshwater content released into the ocean waters coincides with a maximum in wind stress curl and this rapid influx of freshwater into the Arctic circulation forces a large volume of freshwater to outflow into the North Atlantic basin, affecting the Atlantic Meridional Overturning Circulation. The Beaufort Gyre has formed a dome of freshwater that has expanded vertically by about 15 centimetres since 2002, the freshwater within this gyre represents about 10% of all the freshwater in the Arctic Ocean, the majority of the Arctics freshwater supply originates from Russian rivers as runoff. The clockwise circulation of the Beaufort Gyre is induced by the patterns associated with the permanent anticyclonic high pressure system over the western part of the Arctic
Beaufort Gyre
–
Transpolar Drift and Beaufort Gyre are major
ocean currents within the
Arctic Ocean.
60.
Ross Gyre
–
The Ross Gyre is one of the two gyres that exist within the Southern Ocean. The gyre is located in the Ross Sea, and rotates clockwise, the gyre is formed by interactions between the Antarctic Circumpolar Current and the Antarctic Continental Shelf. Sea ice has been noted to persist in the area of the gyre. There is some evidence that global warming has resulted in decrease of the salinity of the waters of the Ross Gyre since the 1950s. Oceanic current Physical oceanography Weddell Gyre
Ross Gyre
–
Location of the Ross Gyre in the
Ross Sea
61.
Atmospheric circulation
–
Atmospheric circulation is the large-scale movement of air, and together with ocean circulation is the means by which thermal energy is redistributed on the surface of the Earth. The Earths atmospheric circulation varies from year to year, but the scale structure of its circulation remains fairly constant. The Earths weather is a consequence of its illumination by the Sun, the atmospheric circulation can be viewed as a heat engine driven by the Suns energy, and whose energy sink, ultimately, is the blackness of space. Over very long periods, a tectonic uplift can significantly alter their major elements, such as the jet stream. During the extremely hot climates of the Mesozoic, a third desert belt may have existed at the Equator, the wind belts girdling the planet are organised into three cells in each hemisphere, the Hadley cell, the Ferrel cell, and the Polar cell. Those cells exist in both the northern and southern hemispheres, the vast bulk of the atmospheric motion occurs in the Hadley cell. The high pressure systems acting on the Earths surface are balanced by the low pressure systems elsewhere, as a result, there is a balance of forces acting on the Earths surface. The atmospheric circulation pattern that George Hadley described was an attempt to explain the trade winds, the Hadley cell is a closed circulation loop which begins at the equator. There, moist air is warmed by the Earths surface, decreases in density, a similar air mass rising on the other side of the equator forces those rising air masses to move poleward. The rising air creates a low pressure zone near the equator, as the air moves poleward, it cools, becomes more dense, and descends at about the 30th parallel, creating a high-pressure area. The descended air then travels toward the equator along the surface, replacing the air that rose from the equatorial zone, the poleward movement of the air in the upper part of the troposphere deviates toward the east, caused by the coriolis acceleration. At the ground however, the movement of the air toward the equator in the lower troposphere deviates toward the west. The winds that flow to the west at the level in the Hadley cell are called the Trade Winds. The zone where the greatest heating takes place is called the thermal equator, as the southern hemisphere summer is December to March, the movement of the thermal equator to higher southern latitudes takes place then. The Hadley system provides an example of a thermally direct circulation, the thermodynamic efficiency and power of the Hadley system, considered as a heat engine, is estimated at 200 terawatts. The Polar cell, likewise, is a simple system, though cool and dry relative to equatorial air, the air masses at the 60th parallel are still sufficiently warm and moist to undergo convection and drive a thermal loop. At the 60th parallel, the air rises to the tropopause, as it does so, the upper level air mass deviates toward the east. When the air reaches the areas, it has cooled and is considerably denser than the underlying air
Atmospheric circulation
–
Highly idealised depiction of the global circulation on Earth.
Atmospheric circulation
–
The
ITCZ 's band of clouds over the
Eastern Pacific and the
Americas as seen from space
62.
Boundary current
–
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, broad 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, narrow, 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 also 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, narrower 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
Boundary current
–
The main ocean currents involved with the North Pacific Gyre
63.
Coriolis force
–
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
Coriolis force
–
This
low-pressure system over
Iceland spins counter-clockwise due to balance between the Coriolis force and the pressure gradient force.
Coriolis force
–
Coordinate system at latitude φ with x -axis east, y -axis north and z -axis upward (that is, radially outward from center of sphere).
Coriolis force
–
Cloud formations in a famous image of Earth from Apollo 17, makes similar circulation directly visible
Coriolis force
–
A carousel is rotating counter-clockwise. Left panel: a ball is tossed by a thrower at 12:00 o'clock and travels in a straight line to the center of the carousel. While it travels, the thrower circles in a counter-clockwise direction. Right panel: The ball's motion as seen by the thrower, who now remains at 12:00 o'clock, because there is no rotation from their viewpoint.
64.
Ekman transport
–
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
Ekman transport
–
Ekman Transport is the net motion of fluid as the result of a balance between Coriolis and turbulent drag forces. In the picture above, the wind blowing North creates a surface stress and a resulting
Ekman spiral is found below it in the
water column.
Ekman transport
–
Diving medicine:
65.
Great Pacific garbage patch
–
The Great Pacific garbage patch, also described as the Pacific trash vortex, is a gyre of marine debris particles in the central North Pacific Ocean discovered between 1985 and 1988. It is located roughly between 135°W to 155°W and 35°N and 42°N, the patch extends over an indeterminate area of widely varying range depending on the degree of plastic concentration used to define the affected area. The patch is characterized by high relative concentrations of pelagic plastics, chemical sludge. Its low density prevents detection by satellite photography, or even by casual boaters or divers in the area and it consists primarily of a small increase in suspended, often microscopic, particles in the upper water column. The great Pacific garbage patch was described in a 1988 paper published by the National Oceanic and Atmospheric Administration of the United States, the description was based on results obtained by several Alaska-based researchers between 1985 and 1988 that measured neustonic plastic in the North Pacific Ocean. Researchers found high concentrations of marine debris accumulating in regions governed by ocean currents and they specifically indicated the North Pacific Gyre. Charles J. Moore, returning home through the North Pacific Gyre after competing in the Transpac sailing race in 1999, Moore alerted the oceanographer Curtis Ebbesmeyer, who subsequently dubbed the region the Eastern Garbage Patch. The area is featured in media reports as an exceptional example of marine pollution. The patch is not easily visible, because it consists of tiny pieces almost invisible to the naked eye, a similar patch of floating plastic debris is found in the Atlantic Ocean, called the North Atlantic garbage patch. The garbage patch occupies a large and relatively stationary region of the North Pacific Ocean bound by the North Pacific Gyre, the gyres rotational pattern draws in waste material from across the North Pacific Ocean, including coastal waters off North America and Japan. As material is captured in the currents, wind-driven surface currents gradually move floating debris toward the center, there is no strong scientific data concerning the origins of pelagic plastics. The figure that an estimated 80% of the garbage comes from land-based sources, according to a 2011 EPA report, The primary source of marine debris is the improper waste disposal or management of trash and manufacturing products, including plastics. Debris is generated on land at marinas, ports, rivers, harbors, docks, debris is generated at sea from fishing vessels, stationary platforms and cargo ships. Pollutants range in size from abandoned fishing nets to micro-pellets used in abrasive cleaners, currents carry debris from the west coast of North America to the gyre in about six years, and debris from the east coast of Asia in a year or less. The size of the patch is unknown, because large items readily visible from a deck are uncommon. Most debris consists of plastic particles suspended at or just below the surface. Instead, the size of the patch is determined by sampling, estimates of size range from 700,000 square kilometres to more than 15,000,000 square kilometres, or, in some media reports, up to twice the size of the continental United States. Such estimates, however, are given the complexities of sampling
Great Pacific garbage patch
–
The Patch is created in the gyre of the North Pacific Subtropical Convergence Zone
Great Pacific garbage patch
–
The area of increased plastic particles is located within the
North Pacific Gyre, one of the five major oceanic
gyres.
66.
Indian Ocean garbage patch
–
The patch does not appear as a continuous debris field. As with other patches in each of the five oceanic gyres, the plastics in it break down to ever smaller particles, and to constituent polymers. As with the patches, the field constitutes an elevated level of pelagic plastics, chemical sludge. The North Atlantic garbage patch was discovered in 2010, the existence of the Great Pacific garbage patch, the first to be discovered, was predicted in a 1988 paper published by the National Oceanic and Atmospheric Administration of the United States. The prediction was based on results obtained by several Alaska-based researchers between 1985 and 1988 that measured neustonic plastic in the North Pacific Ocean. Research studying trash washed onto beaches in and around the Indian Ocean suggested that there would be found in the water column in the Indian Ocean as well. On the Indian Ocean leg of their trip, they travelled between Perth, Australia, and Port Louis, Mauritius, each of the samples they collected in the 4,800 km between contained plastic. They found that the South Atlantic, South Pacific, and Indian Ocean gyres were affected in the way as the North Pacific. Anna Cummins, cofounder of 5 Gyres Institute called the pollution they found a thin plastic soup, Great Pacific garbage patch North Atlantic garbage patch Plastisphere Notes Further reading Gregory, M. R. Ryan, P. G. Pelagic plastics and other seaborne persistent synthetic debris, a review of Southern Hemisphere perspectives, in Coe, J. M. & Rogers, D. B. eds. CS1 maint, Uses editors parameter Masahisa Kubota, Katsumi Takayama, movement and accumulation of floating marine debris simulated by surface currents derived from satellite data. School of Marine Science and Technology, Tokai University, retrieved 28 July 2010. com Sea of Trash – New York Times Magazine Captain Charles Moore on the seas of plastic Charles Moore, Sailing the Great Pacific Garbage Patch – TED Conference talk
Indian Ocean garbage patch
–
There are trash vortices in each of the five major oceanic
gyres.
67.
Marine debris
–
Marine debris, also known as marine litter, is human-created waste that has deliberately or accidentally been released in a lake, sea, ocean or waterway. Floating oceanic debris tends to accumulate at the center of gyres and on coastlines, frequently washing aground, deliberate disposal of wastes at sea is called ocean dumping. Naturally occurring debris, such as driftwood, are also present, with the increasing use of plastic, human influence has become an issue as many types of plastics do not biodegrade. Waterborne plastic poses a threat to fish, seabirds, marine reptiles. Dumping, container spillages, litter washed into storm drains and waterways, more recent studies have found that more than half of plastic debris found on Korean shores is ocean-based. Six pack rings, in particular, are considered emblematic of the problem, the US military used ocean dumping for unused weapons and bombs, including ordinary bombs, UXO, landmines and chemical weapons from at least 1919 until 1970. Millions of pounds of ordnance were disposed of in the Gulf of Mexico and off the coasts of at least 16 states, eighty percent of marine debris is plastic. Plastics accumulate because they typically do not biodegrade as many other substances do and they photodegrade on exposure to sunlight, although they do so only under dry conditions, as water inhibits photolysis. Fishing nets left or lost in the ocean by fishermen – ghost nets – can entangle fish, dolphins, sea turtles, sharks, dugongs, crocodiles, seabirds, crabs and other creatures. These nets restrict movement, causing starvation, laceration and infection,8.8 million metric tons of plastic waste are dumped in the worlds oceans each year. Asia was the source of mismanaged plastic waste, with China alone accounting for 2.4 million metric tons. Plastic waste has reached all the worlds oceans and this plastic pollution harms an estimated 100,000 sea turtles and marine mammals and 1,000,000 sea creatures each year. Microplastics on the other hand harm smaller marine life, pelagic plastic pieces in the center of our ocean’s gyres for example outnumber live marine plankton, and are passed up the food chain to reach all marine life. A1994 study of the seabed using trawl nets in the North-Western Mediterranean around the coasts of Spain, France, plastic debris accounted for 77%, of which 93% was plastic bags. Nurdles, also known as mermaids tears, are plastic pellets, typically under five millimetres in diameter and they are a raw material in plastics manufacturing, and enter the natural environment when spilled. Research performed by MBARI found items including plastic bags below 2000m depth off the west coast of North America, an estimated 10,000 containers at sea each year are lost by container ships, usually during storms. One spillage occurred in the Pacific Ocean in 1992, when thousands of rubber ducks, the toys have since been found all over the world, providing a better understanding of ocean currents. Similar incidents have happened before, such as when Hansa Carrier dropped 21 containers, in 2007, MSC Napoli beached in the English Channel, dropping hundreds of containers, most of which washed up on the Jurassic Coast, a World Heritage Site
Marine debris
–
Marine debris on the
Hawaiian coast
Marine debris
–
Debris on beach near
Dar es Salaam, Tanzania
Marine debris
–
Debris collected from beaches on Tern Island in the
French Frigate Shoals over one month
Marine debris
–
A handful of
nurdles, spilt from a train in
Pineville,
Louisiana
68.
North Atlantic garbage patch
–
The North Atlantic garbage patch is an area of man-made marine debris found floating within the North Atlantic Gyre, originally documented in 1972. The patch is estimated to be hundreds of kilometres across in size, the debris zone shifts by as much as 1,600 km north and south seasonally, and drifts even farther south during the El Niño-Southern Oscillation, according to the NOAA. To study the scale of the debris accumulation in the area. Nearly 7,000 students from the SEA semester program have been dragging 6,100 fine-mesh nets through the Atlantic over 22 years. The gyre in the North Atlantic Ocean contains plastic marine pollution in a pattern, while eating their normal source of food, plastic ingestion can be unavoidable to wildlife. On 11 April 2013 in order to create awareness, artist Maria Cristina Finucci founded The Garbage patch state at UNESCO –Paris in front of Director General Irina Bokova, first of a series of events under the patronage of UNESCO and of Italian Ministry of the Environment
North Atlantic garbage patch
–
The five major
ocean gyres.
69.
Thermohaline circulation
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Thermohaline circulation is a part of the large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes. The adjective thermohaline derives from thermo- referring to temperature and -haline referring to salt content, wind-driven surface currents travel polewards from the equatorial Atlantic Ocean, cooling en route, and eventually sinking at high latitudes. This dense water then flows into the ocean basins, while the bulk of it upwells in the Southern Ocean, the oldest waters upwell in the North Pacific. Extensive mixing therefore takes place between the basins, reducing differences between them and making the Earths oceans a global system. On their journey, the water masses transport both energy and matter around the globe, as such, the state of the circulation has a large impact on the climate of the Earth. The thermohaline circulation is called the ocean conveyor belt, the great ocean conveyor, or the global conveyor belt. On occasion, it is used to refer to the overturning circulation. Moreover, temperature and salinity gradients can lead to circulation effects that are not included in the MOC itself. The movement of surface currents pushed by the wind is fairly intuitive, for example, the wind easily produces ripples on the surface of a pond. Thus the deep ocean—devoid of wind—was assumed to be perfectly static by early oceanographers, however, modern instrumentation shows that current velocities in deep water masses can be significant. In general ocean water velocities range from fractions of centimeters per second to more than 1 m/s in surface currents like the Gulf Stream. In the deep ocean, the predominant driving force is differences in density, caused by salinity, there is often confusion over the components of the circulation that are wind and density driven. Note that ocean currents due to tides are also significant in places, most prominent in relatively shallow coastal areas. There they are thought to facilitate mixing processes, especially diapycnal mixing. The density of water is not globally homogeneous, but varies significantly and discretely. Sharply defined boundaries exist between water masses which form at the surface, and subsequently maintain their own identity within the ocean, but these sharp boundaries are not to be imagined spatially but rather in a T-S-diagram where water masses are distinguished. They position themselves above or below each other according to their density, warm seawater expands and is thus less dense than cooler seawater. Saltier water is denser than water because the dissolved salts fill interstices between water molecules, resulting in more mass per unit volume
Thermohaline circulation
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Global map of average Sea Surface Density
Thermohaline circulation
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A summary of the path of the thermohaline circulation. Blue paths represent deep-water currents, while red paths represent surface currents.
Thermohaline circulation
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Benjamin Franklin 's map of the
Gulf Stream
