The Drake Passage (referred to as Mar de Hoces Hoces Sea"in Spanish-speaking countries) is the body of water between South America's

Cape Horn Cape Horn ( es, Cabo de Hornos, ) is the southernmost headland of the Tierra del Fuego archipelago of southern Chile, and is located on the small Hornos Island. Although not the most southerly point of South America (which are the Diego Ramí ...

, Chile and the

South Shetland Islands The South Shetland Islands are a group of Antarctic islands with a total area of . They lie about north of the Antarctic Peninsula, and between southwest of the nearest point of the South Orkney Islands. By the Antarctic Treaty of 195 ...

of Antarctica. It connects the southwestern part of the Atlantic Ocean ( Scotia Sea) with the southeastern part of the Pacific Ocean and extends into the

Southern Ocean The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the World Ocean, generally taken to be south of 60° S latitude and encircling Antarctica. With a size of , it is regarded as the second-smal ...

. The Drake Passage is considered one of the most treacherous voyages for ships to make. Currents at its latitude meet no resistance from any landmass, and waves top , hence its reputation as "the most powerful convergence of seas". As the Drake Passage is the narrowest passage around Antarctica, its existence and shape strongly influence the circulation of water around Antarctica and the global oceanic circulation, as well as the global climate. The

bathymetry Bathymetry (; ) is the study of underwater depth of seabed, ocean floors (''seabed topography''), lake floors, or river floors. In other words, bathymetry is the underwater equivalent to hypsometry or topography. The first recorded evidence of w ...

of the Drake Passage plays an important role in the global mixing of oceanic water. It is one of the most treacherous bodies of water on earth.

History

Sailing south from the entrance of the Strait of Magellan, Spanish navigator Francisco de Hoces discovered this passage in 1525, making him the first European to pass through it.Oyarzun, Javier, ''Expediciones españolas al Estrecho de Magallanes y Tierra de Fuego'', 1976, Madrid: Ediciones Cultura Hispánica For this reason, it appears as Mar de Hoces in most Spanish and Spanish American maps and sources. The passage received its English name from the 16th-century explorer

Francis Drake Sir Francis Drake ( – 28 January 1596) was an English explorer, sea captain, privateer, slave trader, naval officer, and politician. Drake is best known for his circumnavigation of the world in a single expedition, from 1577 to 1580 ...

during his circumnavigation. After passing through the Strait of Magellan with ''Marigold'', ''Elizabeth'', and his

flagship A flagship is a vessel used by the commanding officer of a group of naval ships, characteristically a flag officer entitled by custom to fly a distinguishing flag. Used more loosely, it is the lead ship in a fleet of vessels, typically the f ...

''Golden Hind'', Drake entered the Pacific Ocean and was blown far south in a tempest. ''Marigold'' was lost, and ''Elizabeth'' abandoned the fleet. Only Drake's Golden Hind entered the passage. This incident demonstrated to the English that there was open water south of South America. The first recorded voyage through the passage was that of ''Eendracht'', captained by the Dutch navigator

Jacob Le Maire Jacob Le Maire (c. 1585 – 22 December 1616) was a Dutch mariner who circumnavigated the earth in 1615 and 1616. The strait between Tierra del Fuego and Isla de los Estados was named the Le Maire Strait in his honour, though not without controv ...

in 1616, naming Cape Horn in the process. The first human-powered transit (by rowing) across the passage was accomplished on December 25, 2019. Their accomplishment became the subject of a 2020 documentary, '' The Impossible Row''.

Geography

The Drake Passage opened when Antarctica separated from South America due to

plate tectonics Plate tectonics (from the la, label= Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large t ...

. There is much debate about when that occurred. The opening had a major effect on the global oceans due to deep currents like the Antarctic Circumpolar Current (ACC). This opening could have been a primary cause of changes in global circulation and climate, as well as the rapid expansion of Antarctic ice sheets, because as Antarctica was encircled by ocean currents it was cut off from receiving heat from warmer regions. Precise dating of the earliest opening of the Drake Passage is complicated by the existence of plate fragments, which have been reconstructed to show the age of the earliest opening. The passage between Cape Horn and

Livingston Island Livingston Island (Russian name ''Smolensk'', ) is an Antarctic island in the Southern Ocean, part of the South Shetlands Archipelago, a group of Antarctic islands north of the Antarctic Peninsula. It was the first land discovered south of 60� ...

is the shortest crossing from Antarctica to another landmass. The boundary between the Atlantic and Pacific Oceans is sometimes taken to be a line drawn from Cape Horn to Snow Island ( north of mainland Antarctica), though the

International Hydrographic Organization The International Hydrographic Organization (IHO) is an intergovernmental organisation representing hydrography. , the IHO comprised 98 Member States. A principal aim of the IHO is to ensure that the world's seas, oceans and navigable waters ...

defines it as the meridian that passes through Cape Horn—67° 16′ W. Both lines lie within the Drake Passage. The other two passages around the extreme southern part of South America (though not going around Cape Horn as such), the Strait of Magellan and

Beagle Channel Beagle Channel (; Yahgan: ''Onašaga'') is a strait in the Tierra del Fuego Archipelago, on the extreme southern tip of South America between Chile and Argentina. The channel separates the larger main island of Isla Grande de Tierra del Fuego ...

, are narrow, leaving little maneuvering room for a ship. They can become icebound. Sometimes the wind blows so strongly that no sailing vessel can make headway against it. Most sailing ships thus prefer the Drake Passage, which is open water for hundreds of miles. The small

Diego Ramírez Islands The Diego Ramírez Islands ( es, Islas Diego Ramírez) are a small group of subantarctic islands located in the southernmost extreme of Chile. History The islands were first sighted on 12 February 1619 by the Spanish Garcia de Nodal expedition ...

lie about south-southwest of Cape Horn. No significant land sits at the

latitude In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north po ...

s of the Drake Passage. That is important to the unimpeded flow eastward of the Antarctic Circumpolar Current, which carries a huge volume of water through the passage and around Antarctica. The passage hosts whales, dolphins and seabirds including giant petrels, other petrels,

albatross Albatrosses, of the biological family Diomedeidae, are large seabirds related to the procellariids, storm petrels, and diving petrels in the order Procellariiformes (the tubenoses). They range widely in the Southern Ocean and the North P ...

es and penguins.

Importance in physical oceanography

The presence of the Drake Passage allows the three main ocean basins (Atlantic, Pacific and Indian) to be connected via the Antarctic Circumpolar current, the strongest oceanic current, with an estimated transport of 100–150 Sv ( Sverdrups, million m³/s). This flow is the only large-scale exchange occurring between the global oceans, and the Drake passage is the narrowest passage on its flow around Antarctica. A significant amount of research has been done in understanding how the shape of the Drake passage (bathymetry and width) affects the global climate.

Oceanic and climate interactions

''"Major features of the modern ocean’s temperature and salinity fields, including the overall thermal asymmetry between the hemispheres, the relative saltiness of deep water formed in the northern hemisphere, and the existence of a transequatorial conveyor circulation, develop after Drake Passage is opened"''''.'' Flow from the Antarctic Circumpolar Current to the other ocean basins

Flow from the Antarctic Circumpolar Current to the other ocean basins

The importance of an open Drake Passage extends far more than the

latitudes. The

Roaring Forties The Roaring Forties are strong westerly winds found in the Southern Hemisphere, generally between the latitudes of 40°S and 50°S. The strong west-to-east air currents are caused by the combination of air being displaced from the Equator ...

and the Furious Fifties blow around Antarctica and drive the Antarctic Circumpolar Current. As a result of the Ekman Transport, water gets transported northward from the Antarctic Circumpolar Current (on the left-hand side while facing the stream direction). Using a

lagrangian approach Lagrangian may refer to: Mathematics * Lagrangian function, used to solve constrained minimization problems in optimization theory; see Lagrange multiplier ** Lagrangian relaxation, the method of approximating a difficult constrained problem with ...

, water parcels passing through the Drake Passage can be followed in their journey in the oceans. Around 23 Sv of water is transported from the Drake Passage to the equator, mainly in the Atlantic and Pacific oceans. To make a blunt comparison, this value is not far from the

Gulf Stream The Gulf Stream, together with its northern extension the North Atlantic Drift, is a warm and swift Atlantic ocean current that originates in the Gulf of Mexico and flows through the Straits of Florida and up the eastern coastline of the Uni ...

transport in the Florida Strait (33 Sv), but is an order of magnitude lower than the transport of the Antarctic Circumpolar Current (100–150 Sv). Water transported from the

to the Northern Hemisphere contributes to the global mass balance and permits the meridional circulation across the oceans. Several studies linked the current shape of the Drake Passage to an effective Atlantic Meridional Overturning Circulation (AMOC). Models have been run with different widths and depths of the Drake Passage, and consequent changes in the global oceanic circulation and temperature distribution have been analysed. It appears that the “conveyor belt” of the global Thermohaline Circulation appears only in presence of an open Drake Passage, subject to wind forcing. In particular, with a closed Drake Passage, there is no North Atlantic Deep Water cell, and no Antarctic Circumpolar Current (obviously, as Antarctica is not completely surrounded by water). With a shallower Drake Passage, a weak Antarctic Circumpolar Current appears, but still no North Atlantic Deep Water cell. Conveyor belt

Parallelly, it has been shown that present-day distribution of

dissolved inorganic carbon Dissolved inorganic carbon (DIC) is the sum of the aqueous species of inorganic carbon in a solution. Carbon compounds can be distinguished as either organic or inorganic, and as dissolved or particulate, depending on their composition. Organic ...

can be obtained only with an open Drake Passage. In short, not only the Drake Passage must be open to allow the Antarctic Circumpolar Current to flow around Antarctica, but also the current topography is the only one that allows enough transport from the

to sustain a North Atlantic Deep Water cell, thus allowing a sufficiently strong thermohaline circulation. To make a connection with the global surface temperature, an open (and sufficiently deep) Drake Passage cools the

and warms the high latitudes of the northern hemisphere. Indeed, the isolation of Antarctica by the Antarctic Circumpolar Current (that can flow only with an open Drake Passage) is credited by many researchers with causing the glaciation of the continent and global cooling in the

Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...

epoch.

Turbulence and mixing

Diapycnal mixing is the process by which different layers of a stratified fluid mix. It directly affects vertical gradients, thus it is of great importance in all the gradient-driven type of transport and circulation (such as the thermohaline circulation). In a simplified way, mixing drives the global thermohaline circulation: without internal mixing, cooler water would never be above warmer water, and there would be no density(buoyancy)-driven circulation. However, mixing in the interior of most of the ocean is thought to be ten times weaker than required to support the global circulation. It has been hypothesised that the extra-mixing can be ascribed to breaking of

internal waves Internal waves are gravity waves that oscillate within a fluid medium, rather than on its surface. To exist, the fluid must be stratified: the density must change (continuously or discontinuously) with depth/height due to changes, for example, in ...

( Lee waves). When a stratified fluid reaches an internal obstacle, a wave is created that can eventually break, mixing the fluid’s layers. It has been estimated that the diapycnal diffusivity in the Drake Passage is ~20 times the value immediately to the west in the Pacific sector of the Antarctic Circumpolar Current. Much of the energy that is dissipated through internal wave breaking (around 20% of the wind energy put into the ocean) gets dissipated in the

southern ocean The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the World Ocean, generally taken to be south of 60° S latitude and encircling Antarctica. With a size of , it is regarded as the second-smal ...

. In short, without the coarse topography in the depths of the Drake Passage, oceanic internal mixing would be weaker, and the global circulation would be affected. DensityDrivenCirculation

Historical importance in oceanographic observations

Worldwide satellite measurements of oceanic properties are available since the 1980s. Before then, data could be only gathered through oceanic ships taking direct measurements. The Antarctic Circumpolar Current has been (and is) surveyed making repeated transects. South America and the

Antarctic Peninsula The Antarctic Peninsula, known as O'Higgins Land in Chile and Tierra de San Martín in Argentina, and originally as Graham Land in the United Kingdom and the Palmer Peninsula in the United States, is the northernmost part of mainland Antarctic ...

constrain the Antarctic Circumpolar Current in the Drake Passage: the convenience of measuring the Antarctic Circumpolar Current across the passage lays in the clear boundaries of the current in that stripe. Even after the advent of satellite altimetry data, direct observations in the Drake Passage have not lost their exceptionality. The relative shallowness and narrowness of the passage makes it particularly suitable to assess the validity of horizontally ''and'' vertically changing quantities (such as velocity in Ekman’s classic theory). In addition, the strength of the Antarctic Circumpolar Current makes meanders and pinching cold-core cyclonic rings easier to observe.

Fauna

Wildlife in the Drake Passage includes the following species:

Birds

Cetaceans

Gallery

File:Drake2.JPG, Rough seas are common in the Drake Passage File:Drake3.JPG, Tourists watch whales in the Drake Passage File:Drake4.JPG, Seabird (light-mantled sooty albatross) flying over the Drake Passage File:Drake5.JPG,

Humpback whale The humpback whale (''Megaptera novaeangliae'') is a species of baleen whale. It is a rorqual (a member of the family Balaenopteridae) and is the only species in the genus ''Megaptera''. Adults range in length from and weigh up to . The hum ...

s are a common sight in the Drake Passage File:Hourglas dolphin crop.jpg, Hourglass dolphins leaping in the Passage Image:Drake Passage - Lambert Azimuthal projection.png, Drake Passage or ''Mar de Hoces'' between

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...

and

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest co ...

Image:Drake Passage - Orthographic projection.png, Drake Passage

References

External links

National Oceanography Centre, Southampton page of the important and complex bathymetry of the Passage

A NASA image of an eddy in the Passage

{{Coord, 58, 35, S, 65, 54, W, type:waterbody_scale:10000000, display=title Francis Drake Straits of Chile Straits of Antarctica Bodies of water of Magallanes Region Landforms of Tierra del Fuego Province, Argentina Borders of Chile Antarctic region