An ocean current is a continuous, directed movement of seawater generated by a number of forces acting upon the water, including wind, the Coriolis effect , breaking waves , cabbeling , and temperature and salinity differences. Depth contours , shoreline configurations, and interactions with other currents influence a current's direction and strength. Ocean currents move both horizontally, on scales that can span entire oceans, as well as vertically, with vertical currents ( upwelling and downwelling ) playing an important role in the movement of nutrients and gases, such as carbon dioxide, between the surface and the deep ocean.
41-438: Balaenoptera Megaptera Eschrichtiidae ? Ellerman & Morrison-Scott 1951 Rhachianectidae Weber 1904 Rorquals ( / ˈ r ɔːr k w əl z / ) are the largest group of baleen whales , comprising the family Balaenopteridae , which contains nine extant species in two genera . They include the largest known animal that has ever lived, the blue whale , which can reach 180 tonnes (200 short tons), and
82-399: A decisive role in influencing the climates of regions through which they flow. Ocean currents are important in the study of marine debris . Upwellings and cold ocean water currents flowing from polar and sub-polar regions bring in nutrients that support plankton growth, which are crucial prey items for several key species in marine ecosystems . Ocean currents are also important in
123-569: A much colder northern Europe and greater sea-level rise along the U.S. East Coast." In addition to water surface temperatures, the wind systems are a crucial determinant of ocean currents. Wind wave systems influence oceanic heat exchange, the condition of the sea surface, and can alter ocean currents. In the North Atlantic, equatorial Pacific, and Southern Ocean, increased wind speeds as well as significant wave heights have been attributed to climate change and natural processes combined. In
164-533: A new species of balaenopterid, Omura's whale ( Balaenoptera omurai ), was announced in November 2003, which looks similar to, but smaller than, the fin whale ; individuals of this species were found in Indo-Pacific waters. The discovery of the highly endangered Rice's whale was announced in 2021 after a genetic study found it to be distinct from Bryde's whale ; this species is known from a small portion of
205-453: A result, influence the biological composition of oceans. Due to the patchiness of the natural ecological world, dispersal is a species survival mechanism for various organisms. With strengthened boundary currents moving toward the poles, it is expected that some marine species will be redirected to the poles and greater depths. The strengthening or weakening of typical dispersal pathways by increased temperatures are expected to not only impact
246-418: A significant role in influencing climate, and shifts in climate in turn impact ocean currents. Over the last century, reconstructed sea surface temperature data reveal that western boundary currents are heating at double the rate of the global average. These observations indicate that the western boundary currents are likely intensifying due to this change in temperature, and may continue to grow stronger in
287-420: A unique sensory organ consisting of a bundle of mechanoreceptors that helps their brains to coordinate the engulfment action. Furthermore, their large nerves are flexible so that they can stretch and recoil. In fact, they give rorquals the ability to open their mouths so wide that they would be capable of taking in water at volumes greater than their own sizes. These nerves are packed into a central core area that
328-487: A wind-driven current which flows clockwise uninterrupted around Antarctica. The ACC connects all the ocean basins together, and also provides a link between the atmosphere and the deep ocean due to the way water upwells and downwells on either side of it. Ocean currents are patterns of water movement that influence climate zones and weather patterns around the world. They are primarily driven by winds and by seawater density, although many other factors influence them – including
369-425: Is also known as the ocean's conveyor belt. Where significant vertical movement of ocean currents is observed, this is known as upwelling and downwelling . The adjective thermohaline derives from thermo- referring to temperature and -haline referring to salt content , factors which together determine the density of seawater. The thermohaline circulation is a part of the large-scale ocean circulation that
410-509: Is an extreme feeding method, where the whale accelerates to a high velocity and then opens its mouth to a large gape angle. This generates the water pressure required to expand its mouth and engulf and filter a huge amount of water and fish. The gray whale does not lunge feed, as it gulps in sediments from the seafloor rather than water. Rorquals have a number of anatomical features that enable them to do this, including bilaterally separate mandibles , throat pleats that can expand to huge size, and
451-537: Is driven by global density gradients created by surface heat and freshwater fluxes . Wind -driven surface currents (such as the Gulf Stream ) travel polewards from the equatorial Atlantic Ocean , cooling en route, and eventually sinking at high latitudes (forming North Atlantic Deep Water ). This dense water then flows into the ocean basins . While the bulk of it upwells in the Southern Ocean ,
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#1732776827178492-592: Is surrounded by elastin fibers. Opening the mouth causes the nerves to unfold, and they snap back after the mouth is closed. According to Potvin and Goldbogen, lunge feeding in rorquals represents the largest biomechanical event on Earth. Formerly, the rorqual family Balaenopteridae was split into two subfamilies, the Balaenopterinae and the Megapterinae , with each subfamily containing one genus, Balaenoptera and Megaptera , respectively. However,
533-482: The Atlantic meridional overturning circulation (AMOC) is in danger of collapsing due to climate change, which would have extreme impacts on the climate of northern Europe and more widely, although this topic is controversial and remains an active area of research. The "State of the cryosphere" report, dedicates significant space to AMOC, saying it may be enroute to collapse because of ice melt and water warming. In
574-506: The East Australian Current , global warming has also been accredited to increased wind stress curl , which intensifies these currents, and may even indirectly increase sea levels, due to the additional warming created by stronger currents. As ocean circulation changes due to climate, typical distribution patterns are also changing. The dispersal patterns of marine organisms depend on oceanographic conditions, which as
615-645: The Gulf Stream , which, together with its extension the North Atlantic Drift , makes northwest Europe much more temperate for its high latitude than other areas at the same latitude. Another example is Lima, Peru , whose cooler subtropical climate contrasts with that of its surrounding tropical latitudes because of the Humboldt Current . The largest ocean current is the Antarctic Circumpolar Current (ACC),
656-580: The fin whale , which reaches 120 tonnes (130 short tons); even the smallest of the group, the northern minke whale , reaches 9 tonnes (10 short tons). Rorquals take their name from French rorqual , which derives from the Norwegian word røyrkval : the first element røyr originated from the Old Norse name for this type of whale, reyðr , probably related to the Norse word for "red", and
697-401: The global conveyor belt , which plays a dominant role in determining the climate of many of 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
738-509: The humpback whale (which is oceanic but passes close to shore when migrating). It is the largest and the smallest types — the blue whale and Antarctic minke whale — that occupy the coldest waters in the extreme south; the fin whale tends not to approach so close to the ice shelf; the sei whale tends to stay further north again. (In the northern hemisphere, where the continents distort weather patterns and ocean currents , these movements are less obvious, although still present.) Within each species,
779-509: The phylogeny of the various rorqual species shows the current division is paraphyletic , and in 2005, the division into subfamilies was dropped. Two genetic studies, one in 2018 and one in 2020, suggest that the gray whale ( Eschrichtius robustus ) be counted among the rorquals, being more derived than the two minke whales but basal to the humpback whale , fin whale , and the other taxa classified in Balaenoptera . The discovery of
820-545: The right whales , and most have narrow, elongated flippers. They have a dorsal fin, situated about two-thirds the way back. Most rorquals feed by gulping in water, and then pushing it out through the baleen plates with their tongue; the exception is the gray whale , which gulps in and filters large amounts of marine sediments from the seafloor. They feed on crustaceans , such as krill , but also on various fish, such as herrings and sardines . Gestation in rorquals lasts 11–12 months, so that both mating and birthing occur at
861-533: The southern hemisphere . In addition, the areas of surface ocean currents move somewhat with the seasons ; this is most notable in equatorial currents. Deep ocean basins generally have a non-symmetric surface current, in that the eastern equator-ward flowing branch is broad and diffuse whereas the pole-ward flowing western boundary current is relatively narrow. Large scale currents are driven by gradients in water density , which in turn depend on variations in temperature and salinity. This thermohaline circulation
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#1732776827178902-459: The circulation has a large impact on the climate of the Earth. The thermohaline circulation is sometimes called the ocean conveyor belt, the great ocean conveyor, or the global conveyor belt. On occasion, it is imprecisely used to refer to the meridional overturning circulation , (MOC). Since the 2000s an international program called Argo has been mapping the temperature and salinity structure of
943-563: The common (northern) and Antarctic (southern) minke whale species are found in all the oceans of their respective hemispheres; either of Bryde's whale and Eden's whale occur in the Atlantic , Pacific , and Indian oceans, being absent only from the cold waters of the Arctic and Antarctic ; and the gray whale is found in the northern Pacific Ocean, although it was also found in the Atlantic Ocean in historic times. Rice's whale has
984-554: The cost and emissions of shipping vessels. Ocean currents can also impact the fishing industry , examples of this include the Tsugaru , Oyashio and Kuroshio currents all of which influence the western North Pacific temperature, which has been shown to be a habitat predictor for the Skipjack tuna . It has also been shown that it is not just local currents that can affect a country's economy, but neighboring currents can influence
1025-570: The dispersal and distribution of many organisms, inclusing those with pelagic egg or larval stages. An example is the life-cycle of the European Eel . Terrestrial species, for example tortoises and lizards, can be carried on floating debris by currents to colonise new terrestrial areas and islands . The continued rise of atmospheric temperatures is anticipated to have various effects on the strength of surface ocean currents, wind-driven circulation and dispersal patterns. Ocean currents play
1066-875: The genus is currently polyphyletic , with the two aforementioned species being phylogenetically nested within it. This genus is known in the fossil records from the Neogene to the Quaternary (13.65 million years ago to the present). The genus Balaenoptera contains the following extant species and subspecies: Many fossil Balaenoptera species have been described. Some (namely B. borealina , B. definata , B. emarginata , B. gibbosa , B. rostratella , and B. sibbaldina ) are either nondiagnostic, highly fragmentary, or had no holotype specimen named, hence are considered nomina dubia . The valid fossil species of Balaenoptera are: Ocean current Ocean currents flow for great distances and together they create
1107-509: The large scale prevailing winds drive major persistent ocean currents, and seasonal or occasional winds drive currents of similar persistence to the winds that drive them, and the Coriolis effect plays a major role in their development. The Ekman spiral velocity distribution results in the currents flowing at an angle to the driving winds, and they develop typical clockwise spirals in the northern hemisphere and counter-clockwise rotation in
1148-434: The largest individuals tend to approach the poles more closely, while the youngest and fittest ones tend to stay in warmer waters before leaving on their annual migration. Most rorquals breed in tropical waters during the winter, then migrate back to the polar feeding grounds rich in plankton and krill for the short polar summer. As well as other methods, rorquals obtain prey by lunge-feeding on bait balls . Lunge feeding
1189-462: The near future. There is evidence that surface warming due to anthropogenic climate change has accelerated upper ocean currents in 77% of the global ocean. Specifically, increased vertical stratification due to surface warming intensifies upper ocean currents, while changes in horizontal density gradients caused by differential warming across different ocean regions results in the acceleration of surface zonal currents . There are suggestions that
1230-450: The northeastern Gulf of Mexico . In 2012, the following alternate taxonomy was presented: Balaenoptera See text Balaenoptera (from Latin balaena 'whale' and Ancient Greek πτερά ( pterá ) 'fin') is a genus of rorquals containing eight extant species . Balaenoptera comprises all but two of the extant species in its family (the humpback whale and gray whale );
1271-515: The ocean with a fleet of automated platforms that float with the ocean currents. The information gathered will help explain the role the oceans play in the earth's climate. Ocean currents affect temperatures throughout the world. For example, the ocean current that brings warm water up the north Atlantic to northwest Europe also cumulatively and slowly blocks ice from forming along the seashores, which would also block ships from entering and exiting inland waterways and seaports, hence ocean currents play
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1312-656: The oceans. Ocean temperature and motion fields can be separated into three distinct layers: mixed (surface) layer, upper ocean (above the thermocline), and deep ocean. Ocean currents are measured in units of sverdrup (Sv) , where 1 Sv is equivalent to a volume flow rate of 1,000,000 m (35,000,000 cu ft) per second. There are two main types of currents, surface currents and deep water currents. Generally surface currents are driven by wind systems and deep water currents are driven by differences in water density due to variations in water temperature and salinity . Surface oceanic currents are driven by wind currents,
1353-471: The oldest waters (with a transit time of around 1000 years) upwell in the North Pacific. Extensive mixing therefore takes place between the ocean basins, reducing differences between them and making the Earth's oceans a global system. On their journey, the water masses transport both energy (in the form of heat) and matter (solids, dissolved substances and gases) around the globe. As such, the state of
1394-582: The same latitude North America's weather was colder. A good example of this is the Agulhas Current (down along eastern Africa), which long prevented sailors from reaching India. In recent times, around-the-world sailing competitors make good use of surface currents to build and maintain speed. Ocean currents can also be used for marine power generation , with areas of Japan, Florida and Hawaii being considered for test projects. The utilization of currents today can still impact global trade, it can reduce
1435-438: The same time of year. Cows give birth to a single calf, which is weaned after 6–12 months, depending on species. Of some species, adults live in small groups, or "pods" of two to five individuals. For example, humpback whales have a fluid social structure, often engaging behavioral practices in a pod, other times being solitary. Distribution is worldwide: the blue, fin, humpback, and the sei whales are found in all major oceans;
1476-450: The same time, the Antarctic Circumpolar Current (ACC) is also slowing down and is expected to lose 20% of it power by the year 2050, "with widespread impacts on ocean circulation and climate". UNESCO mentions that the report in the first time "notes a growing scientific consensus that melting Greenland and Antarctic ice sheets, among other factors, may be slowing important ocean currents at both poles, with potentially dire consequences for
1517-561: The second from the Norse word hvalr meaning "whale" in general. The family name Balaenopteridae is from the type genus , Balaenoptera . All members of the family have a series of longitudinal folds of skin running from below the mouth back to the navel (except the sei whale and common minke whale , which have shorter grooves). These furrows allow the mouth to expand immensely when feeding. These "pleated throat grooves" distinguish balaenopterids from other whales. Rorquals are slender and streamlined in shape, compared with their relatives
1558-424: The shape and configuration of the ocean basin they flow through. The two basic types of currents – surface and deep-water currents – help define the character and flow of ocean waters across the planet. Ocean currents are driven by the wind, by the gravitational pull of the moon in the form of tides , and by the effects of variations in water density. Ocean dynamics define and describe the motion of water within
1599-626: The smallest distribution of rorquals and possibly baleen whales in general, being endemic to a small portion of the Gulf of Mexico west of the Florida peninsula and south of Alabama and the Florida panhandle , although it likely formerly had a much wider distribution in the Gulf. Most rorquals are strictly oceanic: the exceptions are the gray whale, Bryde's whale, Eden's whale, and Rice's whale (which are usually found close to shore all year round) and
1640-413: The survival of native marine species due to inability to replenish their meta populations but also may increase the prevalence of invasive species . In Japanese corals and macroalgae, the unusual dispersal pattern of organisms toward the poles may destabilize native species. Knowledge of surface ocean currents is essential in reducing costs of shipping, since traveling with them reduces fuel costs. In
1681-527: The wind powered sailing-ship era, knowledge of wind patterns and ocean currents was even more essential. Using ocean currents to help their ships into harbor and using currents such as the gulf stream to get back home. The lack of understanding of ocean currents during that time period is hypothesized to be one of the contributing factors to exploration failure. The Gulf Stream and the Canary current keep western European countries warmer and less variable, while at