Antarctic Circumpolar Current in the context of "Scotia Arc"

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⭐ Core Definition: Antarctic Circumpolar Current

The Antarctic Circumpolar Current (ACC) is an ocean current that flows clockwise (as seen from the South Pole) 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 estimated at 137 ± 7 Sverdrups (Sv, million m/s), or possibly even higher, making it the largest ocean current. The current is circumpolar due to the lack of any landmass connecting with Antarctica and this keeps warm ocean waters away from Antarctica, enabling that continent to maintain its huge ice sheet.

Associated with the Circumpolar Current is the Antarctic Convergence, where the cold Antarctic waters meet the warmer waters of the subantarctic, creating a zone of upwelling nutrients. These nurture high levels of phytoplankton with associated copepods and krill, and resultant food chains supporting fish, whales, seals, penguins, albatrosses, and a wealth of other species.

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👉 Antarctic Circumpolar Current in the context of Scotia Arc

The Scotia Arc is the island arc system forming the north, east and south border of the Scotia Sea. The northern border, the North Scotia Ridge, comprises (from west to east): Isla de los Estados at the tip of Tierra del Fuego, the Burdwood, Davis, and Aurora Banks; the Shag, South Georgia Island and Clerke Rocks. The eastern border comprises the volcanic South Sandwich Islands flanked by the South Sandwich Trench. The southern border, the South Scotia Ridge, comprises (east to west): Herdman, Discovery, Bruce, Pirie, and Jane Banks; the South Orkney Islands and Elephant Island. Finally, the Bransfield Strait separates the arc from the South Shetland Islands and James Ross Island flanking the tip of the Antarctic Peninsula.

The Scotia Arc surrounds the small Scotia and South Sandwich Plates.The arc is formed by continental fragments that once formed a land bridge between South America and Antarctica, which was once part of the subduction margin that still forms the Andes. An ancestral arc, which formed a separate subduction system, broke through this land bridge and started to form the Scotia Sea by eastward back-arc extension driven by subduction of the South American Plate (also located east of the Scotia Arc).Today, the Scotia Arc forms a discontinuous link between South America and Antarctica. It is considered a continuation of the Andes, and the antarctic part of that mountain range is called the Antarctandes. The Scotia Arc is also an important barrier between the Pacific and Atlantic Oceans, and therefore for the Antarctic Circumpolar Current.

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Antarctic Circumpolar Current in the context of Drake Passage

The Drake Passage is the body of water between Cape Horn in Chile at the southern extreme of the South American mainland and the South Shetland Islands 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 passage is named after the 16th-century English explorer and privateer Sir Francis Drake.

The Drake Passage is considered one of the most treacherous voyages for ships to make. The Antarctic Circumpolar Current, which runs through it, meets no resistance from any landmass, and waves top 40 feet (12 m), giving it a reputation for being "the most powerful convergence of seas".

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Antarctic Circumpolar Current in the context of South Pacific Gyre

The Southern Pacific Gyre is part of the Earth's system of rotating ocean currents, bounded by the Equator to the north, Australia to the west, the Antarctic Circumpolar Current to the south, and South America to the east. The center of the South Pacific Gyre is the oceanic pole of inaccessibility, the site on Earth farthest from any continents and productive ocean regions and is regarded as Earth's largest oceanic desert. With an area of 37 million square kilometres, it makes up approximately 10% of the Earth's ocean surface. The gyre, as with Earth's other four gyres, contains an area with elevated concentrations of pelagic plastics, chemical sludge, and other debris known as the South Pacific garbage patch.

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Antarctic Circumpolar Current in the context of South Pacific garbage patch

The South Pacific garbage patch is an area of ocean with increased levels of marine debris and plastic particle pollution, within the ocean's pelagic zone. This area is in the South Pacific Gyre, which itself spans from waters east of Australia to the South American continent, as far north as the Equator, and south until reaching the Antarctic Circumpolar Current. The degradation of plastics in the ocean also leads to a rise in the level of toxics in the area. The garbage patch was confirmed in mid-2017, and has been compared to the Great Pacific Garbage Patch's state in 2007, making the former ten years younger. The South Pacific garbage patch is not visible on satellites, and is not a landmass. Most particles are smaller than a grain of rice. A researcher said: "This cloud of microplastics extends both vertically and horizontally. It's more like smog than a patch".

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Antarctic Circumpolar Current in the context of South Atlantic Gyre

The South Atlantic Gyre is the subtropical gyre in the south Atlantic Ocean. In the southern portion of the gyre, northwesterly (or southeastward-flowing) winds drive eastward-flowing currents that are difficult to distinguish from the northern boundary of the Antarctic Circumpolar Current. Like other oceanic gyres, it collects vast amounts of floating debris as a garbage patch.

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Antarctic Circumpolar Current in the context of Weddell Gyre

The Weddell Gyre is one of the two gyres that exist within the Southern Ocean. The gyre is formed by interactions between the Antarctic Circumpolar Current (ACC) and the Antarctic Continental Shelf. The gyre is located in the Weddell Sea, and rotates clockwise. South of the ACC and spreading northeast from the Antarctic Peninsula, the gyre is an extended large cyclone. Where the northeastern end ends at 30°E, which is marked by the southward turn of the ACC, the northern part of the gyre spreads over the Southern Scotia Sea and goes northward to the South Sandwich Arc. Axis of the gyre is over the southern flanks of the South Scotia, America-Antarctic, and Southwest Indian Ridges. In the southern part of the gyre, the westward return flow is about 66 sverdrup (Sv), while in the northern rim current, there is an eastward flow of 61 Sv.

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