What is the primary cause of the major surface currents found in the north atlantic ocean
The wind exerts stress on the ocean surface proportional to the square of the wind speed and in the direction of the wind, setting the surface water in motion. Upgrade to remove ads. Almost half of stocks are fished at biologically unsustainable levels.
Which type of wave do surfers prefer? What is a "rip current? How is a swimmer advised to escape from a dangerous "rip current?
What are "internal waves? What are "standing waves?
What is the difference between single-node and two-node standing waves? What is a "seiche?
What is a "mega-tsunami" and how does it differ from a "tsunami? What are the four primary causes of a tsunami? What is a typical wavelength, wave height, period and speed of a tsunami? Is a tsunami a "deep water wave" or a "shallow water wave?
How can a tsunami wave pass relatively unnoticed under a ship at sea? What happens to the tsunami wave as it approaches a coast? Why does the water often recede out to sea minutes before a tsunami strikes? How do animals know to flee to higher ground before a tsunami strikes? Where do tsunami typically occur most often? What is a "rogue wave?
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List the major characteristics of rogue waves. Why are rogue waves to devastating to ships at sea? What are the four probable causes of rogue waves? Africa - 3 - Normal part of the wave spectrum: Factors that set surface ocean currents into motions are the global circulation cells Hadley, Ferrel, Polarthe Coriolis effect, and the continental deflection.
If a sword had memory, it might be grateful to the forge fire, but never fond of it. In Oceans and Seas. Categories you should follow. Log in or Sign Up to follow categories. What do Jews think will happen after death? What dissolves in hot water to form solutions? What are Two muscle that bring about opposite effects are known as what? The mid Atlantic ridge essentially divides the Atlantic Ocean floor into two large troughs with depths ranging from meters to meters.
There are also many transverse ridges that run between the two continents.
These transverse ridges and the mid Atlantic ridge together divide the Atlantic Ocean floor into several basins. The ocean floor is made up of occasional deeps, trenches, abyssal plains, seamounts, basins, canyons, plateaus and some guyots. Puerto Rico trench in the North Atlantic Ocean is the deepest trench with a depth of meters. Atlantic Ocean has one of the most saline waters among all the oceans in the world. The salinity in the open ocean varies from 33 to 37 parts per thousand by mass and varies with latitude and season.
The salinity levels are lower in the high latitudes and along the coasts where large rivers enter. But it is found lowest in regions just north of equator because of the heavy tropical rainfall in that region. The temperatures vary with latitude, current systems and seasonal changes. The flow of water in the ocean is affected by the Coriolis Effect. It makes the north Atlantic waters to flow in a clockwise direction and South Atlantic Ocean waters to flow in an anti clockwise direction.
The ocean water is made up of four large water masses. The surface water is made up of north and south Atlantic central waters. Since man-made substances were introduced into the environment, the path of the NADW can be traced throughout its course by measuring tritium and radiocarbon from nuclear weapon tests in the s and CFCs.
The clockwise warm-water North Atlantic Gyre occupies the northern Atlantic, and the counter-clockwise warm-water South Atlantic Gyre appears in the southern Atlantic.
In the North Atlantic surface circulation is dominated by three inter-connected currents: This system of currents transport warm water into the North Atlantic, without which temperatures in the North Atlantic and Europe would plunge dramatically. It is governed by ocean currents from marginal seas and regional topography, rather than being steered by wind, both in the deep ocean and at sea level. Its eastern portion includes eddying branches of the North Atlantic Current which transport warm, saline waters from the subtropics to the north-eastern Atlantic.
The NADW, in its turn, feed the meridional overturning circulation MOCthe northward heat transport of which is threatened by anthropogenic climate change. Large variations in the subpolar gyre on a decade-century scale, associated with the North Atlantic oscillationare especially pronounced in Labrador Sea Waterthe upper layers of the MOC.
The South Atlantic is dominated by the anti-cyclonic southern subtropical gyre. Both these currents receive some contribution from the Indian Ocean. On the African east coast the small cyclonic Angola Gyre lies embedded in the large subtropical gyre. The residence time of the gyre is 4. North Atlantic Deep Water flows southerward below the thermocline of the subtropical gyre.
This population of seaweed probably originated from Tertiary ancestors on the European shores of the former Tethys Ocean and has, if so, maintained itself by vegetative growthfloating in the ocean for millions of years. Other species endemic to the Sargasso Sea include the sargassum fisha predator with algae-like appendages who hovers motionless among the Sargassum. Fossils of similar fishes have been found in fossil bays of the former Tethys Ocean, in what is now the Carpathian region, that were similar to the Sargasso Sea.
The fossils found in the Carpathians in the midth century, often called the "quasi-Sargasso assemblage", finally showed that this assemblage originated in the Carpathian Basin from were it migrated over Sicily to the Central Atlantic where it evolved into modern species of the Sargasso Sea.
The location of the spawning ground for European eels remained unknown for decades. Climate is influenced by the temperatures of the surface waters and water currents as well as winds. Because of the ocean's great capacity to store and release heat, maritime climates are more moderate and have less extreme seasonal variations than inland climates. Precipitation can be approximated from coastal weather data and air temperature from water temperatures. The oceans are the major source of the atmospheric moisture that is obtained through evaporation.
Climatic zones vary with latitude; the warmest zones stretch across the Atlantic north of the equator. The coldest zones are in high latitudes, with the coldest regions corresponding to the areas covered by sea ice. Ocean currents influence climate by transporting warm and cold waters to other regions. The winds that are cooled or warmed when blowing over these currents influence adjacent land areas. The Gulf Stream and its northern extension towards Europe, the North Atlantic Drift is thought to have at least some influence on climate.
For example, the Gulf Stream helps moderate winter temperatures along the coastline of southeastern North America, keeping it warmer in winter along the coast than inland areas. The Gulf Stream also keeps extreme temperatures from occurring on the Florida Peninsula. In the higher latitudes, the North Atlantic Drift, warms the atmosphere over the oceans, keeping the British Isles and north-western Europe mild and cloudy, and not severely cold in winter like other locations at the same high latitude.
The cold water currents contribute to heavy fog off the coast of eastern Canada the Grand Banks of Newfoundland area and Africa's north-western coast. In general, winds transport moisture and air over land areas. Icebergs are common from February to August in the Davis StraitDenmark Straitand the northwestern Atlantic and have been spotted as far south as Bermuda and Madeira. Ships are subject to superstructure icing in the extreme north from October to May.
Persistent fog can be a maritime hazard from May to September, as can hurricanes north of the equator May to December. The United States' southeast coast, especially the Virginia and North Carolina coasts, has a long history of shipwrecks due to its many shoals and reefs.
The Bermuda Triangle is popularly believed to be the site of numerous aviation and shipping incidents because of unexplained and supposedly mysterious causes, but Coast Guard records do not support this belief. Hurricanes are also a natural hazard in the Atlantic, but mainly in the northern part of the ocean, rarely tropical cyclones form in the southern parts.
Hurricanes usually form annually between June and November. This period also saw the first stages of the uplift of the Atlas Mountains. The opening of the Atlantic Ocean coincided with the initial break-up of the supercontinent Pangaeaboth of which were initiated by the eruption of the Central Atlantic Magmatic Province CAMPone of the most extensive and voluminous large igneous provinces in Earth's history associated with the Triassic—Jurassic extinction eventone of Earth's major extinction events.
The extent of the volcanism has been estimated to 4. The formation of the isthmus resulted in the migration and extinction of many land-living animals, known as the Great American Interchangebut the closure of the seaway resulted in a "Great American Schism" as it affected ocean currents, salinity, and temperatures in both the Atlantic and Pacific.
Marine organisms on both sides of the isthmus became isolated and either diverged or went extinct. Geologically the Northern Atlantic is the area delimited to the south by two conjugate margins, Newfoundland and Iberia, and to the north by the Arctic Eurasian Basin. The opening of the Northern Atlantic closely followed the margins of its predecessor, the Iapetus Oceanand spread from the Central Atlantic in six stages: Active and inactive spreading systems in this area are marked by the interaction with the Iceland hotspot.
The apparent fit between the coastlines of the two continents was noted on the first maps that included the South Atlantic and it was also the subject of the first computer-assisted plate tectonic reconstructions in Geologically the South Atlantic can be divided into four segments: It covered an area of 1. Dyke swarms in Brazil, Angola, eastern Paraguay, and Namibia, however, suggest the LIP originally covered a much larger area and also indicate failed rifts in all these areas.
Associated offshore basaltic flows reach as far south as the Falkland Islands and South Africa.
The equatorial segment is the last phase of the break-up, but, because it is located on the Equator, magnetic anomalies cannot be used for dating. This final stage, nevertheless, coincided with or resulted in the end of continental extension in Africa. First small ocean basins opened and a shallow gateway appeared during the Middle Eocene. An embryonic subduction margin is potentially developing west of Gibraltar. The Gibraltar Arc in the western Mediterranean is migrating westward into the Central Atlantic where it joins the converging African and Eurasian plates.
Together these three tectonic forces are slowly developing into a new subduction system in the eastern Atlantic Basin.
Meanwhile, the Scotia Arc and Caribbean Plate in the western Atlantic Basin are eastward-propagating subduction systems that might, together with the Gibraltar system, represent the beginning of the closure of the Atlantic Ocean and the final stage of the Atlantic Wilson Cycle. During the latest glacial stages the now-submerged plains of the Agulhas Bank were exposed above sea level, extending the South African coastline farther south by hundreds of kilometers.
The GCFR is delimited to the north by the Cape Fold Belt and the limited space south of it resulted in the development of social networks out of which complex Stone Age technologies emerged. This group of people not only expanded over the whole of Africa, but also started to disperse out of Africa into Asia, Europe, and Australasia around 65, years ago and quickly replaced the archaic humans in these regions.
Following rapid climate changes at the end of the LGM this region was repopulated by Magdalenian culture.
Other hunter-gatherers followed in waves interrupted by large-scale hazards such as the Laacher See volcanic eruption, the inundation of Doggerland now the North Seaand the formation of the Baltic Sea. This human dispersal left abundant traces along the coasts of the Atlantic Ocean. The MSA population was small and dispersed and the rate of their reproduction and exploitation was less intense than those of later generations.