Ocean gyre in the context of "Marginal sea"

The Sargasso Sea (/sɑːrˈɡæsoʊ/) is a region of the Atlantic Ocean bounded by four currents forming an ocean gyre. It is the only named sea without land boundaries. It is distinguished from other parts of the Atlantic Ocean by its characteristic brown Sargassum seaweed and often calm blue water.

The sea is bounded on the west by the Gulf Stream, on the north by the North Atlantic Current, on the east by the Canary Current, and on the south by the North Atlantic Equatorial Current, the four together forming a clockwise-circulating system of ocean currents termed the North Atlantic Gyre. It lies between 20° and 35° north and 40° and 70° west and is approximately 1,100 kilometres (600 nautical miles) wide by 3,200 km (1,750 nmi) long. Bermuda is near the western fringes of the sea. While all of the above currents deposit marine plants and refuse into the sea, ocean water in the Sargasso Sea is distinctive for its deep blue color and exceptional clarity, with underwater visibility of up to 60 m (200 ft).

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.

The Benguela Current /bɛŋˈɡɛlə/ 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, at around 16°S. The current is driven by the prevailing south easterly trade winds. Inshore of the Benguela Current proper, the south easterly winds drive coastal upwelling, forming the Benguela Upwelling System. The cold, nutrient rich waters that upwell from around 200–300 m (656–984 ft) depth in turn fuel high rates of phytoplankton growth, and sustain the productive Benguela ecosystem.

The Ross Sea is a deep bay of the Southern Ocean in Antarctica, between Victoria Land and Marie Byrd Land and within the Ross Embayment, and is the southernmost sea on Earth. It derives its name from the British explorer James Clark Ross who visited this area in 1841. To the west of the sea lies Ross Island and Victoria Land, to the east Roosevelt Island and Edward VII Peninsula in Marie Byrd Land, while the southernmost part is covered by the Ross Ice Shelf, and is about 200 miles (320 km) from the South Pole. Its boundaries and area have been defined by the New Zealand National Institute of Water and Atmospheric Research as having an area of 637,000 square kilometres (246,000 sq mi).

The circulation of the Ross Sea is dominated by a wind-driven ocean gyre and the flow is strongly influenced by three submarine ridges that run from southwest to northeast. The circumpolar deep water current is a relatively warm, salty and nutrient-rich water mass that flows onto the continental shelf at certain locations. The Ross Sea is covered with ice for most of the year.

A garbage patch is a gyre of marine debris particles caused by the effects of ocean currents and increasing plastic pollution by human populations. These human-caused collections of plastic and other debris are responsible for ecosystem and environmental problems that affect marine life, contaminate oceans with toxic chemicals, and contribute to greenhouse gas emissions. Once waterborne, marine debris becomes mobile. Flotsam can be blown by the wind, or follow the flow of ocean currents, often ending up in the middle of oceanic gyres where currents are weakest.

Within garbage patches, the waste is not compact, and although most of it is near the surface of the ocean, it can be found up to more than 30 metres (100 ft) deep in the water. Patches contain plastics and debris in a range of sizes from microplastics and small scale plastic pellet pollution, to large objects such as fishing nets and consumer goods and appliances lost from flood and shipping loss.