The Benguela Current /bɛŋˈɡweɪlə/ 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 depth in turn fuel high rates of phytoplankton growth, and sustain the productive Benguela ecosystem.
Source waters for the Benguela include cold upwelled waters from the depths of the Atlantic Ocean close inshore, joined further off-shore by nutrient poor water that has crossed the Southern Atlantic from South America as part of South Atlantic Gyre. Eddies from the warm South Indian Ocean Agulhas current along South Africa's east coast do round the Cape of Good Hope from time to time to join the Bengulela current. The Benguela current is 200 to 300 km wide and widens further as it flows north and northwest. Its western, seaward edge is well-defined, with many temporary and seasonal eddies and meanders. There is however a well-defined thermal front between the waters associated with the Benguela Upwelling System and those of the eastward flowing Atlantic currents which are not deflected northward by the African continent. The icy Benguela and the warm, south-flowing Agulhas current do not meet off the Cape of Good Hope (see diagram on the right, above), but there is a body of water off the South African south coast, east and particularly west of Cape Agulhas that consists of eddies from both currents, so that off-shore water temperatures along the south coast of Africa vary chaotically.
Northward winds along the coast result in Ekman transport offshore and upwelling of nutrient rich deep water to the euphotic zone. The intensity of the upwelling event is determined by wind strength. Variations in wind strength cause pulses of upwelling, which propagate to the south along the coast with speeds of 5 to 8 m/s. The pulses are similar to a Kelvin wave, except on a scale of 30 to 60 km instead of 1000 km, and can propagate around the cape depending on wind systems.
Pulses of upwelling induce biological production. In the Benguela system, phytoplankton growth requires a period of upwelling followed by a period of stratification and relatively calm waters. The phytoplankton bloom usually lags the upwelling event by 1 to 4 days and blooms for 4 to 10 days. In order for zooplankton to have a continuous food supply, the phytoplankton blooms must not occur too far apart. Pulses of upwelling in the Benguela system regularly have a duration of 10 days, an optimal period for biological production. It is estimated that the annual new production in the Benguela system is 4.7 × 10^13 gC/y, making the Benguela system 30 to 65 times more productive per unit area than the global ocean average.
While upwelling promotes abundant primary and secondary production in the upper parts of the water column and near the coast, deeper waters with limited oxygen exchange create hypoxic areas called oxygen minimum zones at the coastal shelf and upper coastal slope. The Benguela oxygen minimum zone starts around a depth of 100 m and is a few hundred meters thick. Bacteria that use sulpher rather than oxygen reside in the oxygen minimum zone.
The most abundant fishes in the Benguela system are Sardinops and Engraulis. Sardinops ocelata (pilchard) was intensely fished beginning in the 1950s and peaking in 1968 with landings over 1.3 million tons. Since then, the Sardinops fishery has declined and the Engraulis capensis (anchovy) fishery has taken over.
Similar to the Pacific El Niño, a thick slab of warm, nutrient poor water enters the northern part of the Benguela upwelling system off the Namibia coast about once per decade. During the Benguela Niño, warm, salty waters from the Angola Current move southward, from 15°S to as far as 25°S. This slab of warm salty water extends to 150 km offshore and to 50 m depth. Heavy rains, changes in fish abundance, and temporal proximity to the Pacific El Niño have been observed; however, the causes and effects of the Benguela Niño are not well understood. One research team has shown that the Benguela Niño is caused by winds in the west-central equatorial Atlantic Ocean that propagate as subsurface sea temperature anomalies to the African coast. A recent study has demonstrated the importance of local winds in the development of the Benguela Niño off the coast of Namibia and Angola. This local process together with the remote signal from the equatorial regions form the basis of the formation mechanism in which both processes sometimes reinforce each other.
Abraliopsis atlantica is a species of enoploteuthid cephalopod found in the tropical and subtropical Atlantic Ocean, including the Caribbean Sea, the Gulf of Mexico and the Benguela Current. Female oocytes are around 1 mm in length and number between 4,000 and 29,000 in mature females. There is a lack of information about the species and it is rated as data deficient by the International Union for the Conservation of Nature (IUCN) due to this. It was described by Kir Nesis in 1982.Benguela Current Commission
The Benguela Current Commission, or BCC, is a multi-sectoral inter-governmental, initiative of Angola, Namibia and South Africa. It promotes the sustainable management and protection of the Benguela Current Large Marine Ecosystem, or BCLME. The BCC was established in January 2007 through the signing of an Interim Agreement between the governments of Angola, Namibia and South Africa. Then, on 18 March 2013, the three governments signed the Benguela Current Convention, an environmental treaty that entrenches the Benguela Current Commission as a permanent inter-governmental organization.
The BCC is based on the large marine ecosystem (LME) approach to ocean governance. It is focused on the management of shared fish stocks; environmental monitoring; biodiversity and ecosystem health; the mitigation of pollution; and minimizing the impacts of marine mining and oil and gas production. Sound environmental governance and training and capacity building are at the forefront of its agenda.
The BCC provides a vehicle for Angola, Namibia and South Africa to introduce an ecosystem approach to ocean governance. This means that, instead of managing living and non-living resources at the national level, the three countries work together through the BCC, to address the problems that affect the BCLME.California Current
The California Current is a Pacific Ocean current that moves southward along the western coast of North America, beginning off southern British Columbia and ending off southern Baja California Peninsula. It is considered an Eastern boundary current due to the influence of the North American coastline on its course. It is also one of five major coastal currents affiliated with strong upwelling zones, the others being the Humboldt Current, the Canary Current, the Benguela Current, and the Somali Current. The California Current is part of the North Pacific Gyre, a large swirling current that occupies the northern basin of the Pacific.Cape Peninsula
The Cape Peninsula (Afrikaans: Kaapse Skiereiland) is a generally rocky peninsula that juts out into the Atlantic Ocean at the south-western extremity of the African continent. At the southern end of the peninsula are Cape Point and the Cape of Good Hope. On the northern end is Table Mountain, overlooking Cape Town, South Africa. The peninsula is 52 km long from Mouille point in the north to Cape Point in the south.
The Peninsula has been an island on and off for the past 5 million years, as sea levels fell and rose with the ice age and interglacial global warming cycles of, particularly, the Pleistocene. The last time that the Peninsula was an island was about 1.5 million years ago. Soon afterwards it was joined to the mainland by the emergence from the sea of the sandy area now known as the Cape Flats. The towns and villages of the Cape Peninsula and Cape Flats now form part of the City of Cape Town Metropolitan Municipality.
The Cape of Good Hope is sometimes given as the meeting point of the Atlantic and Indian Oceans. Thus the west coast of the Peninsula is invariably referred to as the "Atlantic Coast", but the eastern side is known as the "False Bay Coast". It is at Cape Point (or the Cape of Good Hope) that the ocean to the south is often said to be divided into the Atlantic Ocean to the west, and the Indian Ocean to the east. However, according to the International Hydrographic Organization agreement that defines the ocean boundaries, the meeting point is at Cape Agulhas, about 200 km (120 mi) to the southeast.Similarly, Cape Point is not the fixed "meeting point" of the cold Benguela Current, running northwards along the west coast of Africa, and the warm Agulhas Current, running south from the equator along the east coast of Africa. In fact the south flowing Agulhas Current swings away from the African coastline between about East London and Port Elizabeth, from where it follows the edge of the Continental shelf roughly as far as the southern tip of the Agulhas Bank, 250 km (155 miles) south of Cape Agulhas. From there it is retroflexed (turned sharply round) in an easterly direction by the South Atlantic, South Indian and Southern Ocean currents, known as the "West Wind Drift", which flow eastwards round Antarctica. The Benguela Current, on the other hand, is an upwelling current which brings cold, mineral-rich water from the depths of the Atlantic Ocean to the surface along the west coast of Southern Africa. Having reached the surface it flows northwards as a result of the prevailing wind and Coriolis forces. The Benguela Current, therefore, effectively starts at Cape Point, and flows northwards from there, although further out to sea it is joined by surface water that has crossed the South Atlantic from South America as part of the South Atlantic Gyre. Thus the Benguela and Agulhas currents do not strictly "meet" anywhere, although eddies from the Agulhas current do from time to time round the Cape to join the Benguela Current.Cocobeach
Cocobeach is a town in northwestern Gabon, lying on the south bank of the Muni River. It is the capital of the Noya Department. It has a beach and is the main border town for Equatorial Guinea, ferries sailing to Cogo across the river and the border.
The town is very small, containing just a fishing village, a small market and a number of adjacent beaches. It is one of the major travel destinations in the region owing to the Crystal Mountains inland from the town, which contain some of the oldest rainforests in Gabon. These were able to largely escape the drying effect of glacial periods of the Quaternary due to the persistent fog from the Benguela Current providing moisture during the dry season.Crowned cormorant
The crowned cormorant (Microcarbo coronatus) is a small cormorant that is endemic to the waters of the cold Benguela Current of southern Africa. It is an exclusively coastal species and is not found more than 10 km (6 mi) away from land. This species is related to the reed cormorant, and was formerly considered to the same species.Discovery Investigations
The Discovery Investigations were a series of scientific cruises and shore-based investigations into the biology of whales in the Southern Ocean. They were funded by the British Colonial Office and organised by the Discovery Committee in London, which was formed in 1918. They were intended to provide the scientific background to stock management of the commercial Antarctic whale fishery.
The work of the Investigations contributed hugely to our knowledge of the whales, the krill they fed on, and the oceanography of their habitat, while charting the local topography, including Atherton Peak. The investigations continued until 1951, with the final report being published in 1980.Good Hope Jet
The Good Hope Jet is the northward-running shelf edge frontal jet of the Southern Benguela Current off the Cape Peninsula of South Africa's west coast. The jet, an intrusion of water from the Agulhas Current, was first described by South African oceanographers, Nils Bang and W.R.H. (Bill) Andrews in 1974. This warm water jet forms a sharp front as it comes into contact with the colder upwelled water over the shelf and plays a key role in carrying fish eggs and larvae from their food-poor Agulhas Bank spawning grounds to inshore nurseries.Leeuwin Current
The Leeuwin Current is a warm ocean current which flows southwards near the western coast of Australia. It rounds Cape Leeuwin to enter the waters south of Australia where its influence extends as far as Tasmania.
The West Australian Current and Southern Australian Countercurrent, which are produced by the West Wind Drift on the southern Indian Ocean and at Tasmania, respectively, flow in the opposite direction, producing one of the most interesting oceanic current systems in the world.
Its strength varies through the year; it is weakest during the summer months (winter in the northern hemisphere) from November to March when the winds tend to blow strongly from the south west northwards. The greatest flow is in the autumn and winter (March to November) when the opposing winds are weakest. Evaporation from the Leeuwin current during this period contributes greatly to the rainfall in the southwest region of Western Australia.
Typically the Leeuwin Current's speed and its eddies are about 1 knot (50 cm/s), although speeds of 2 knots (1 m/s) are common, and the highest speed ever recorded by a drifting satellite-tracked buoy was 3.5 knots (6.5 km/h). The Leeuwin Current is shallow for a major current system, by global standards, being about 300 m deep, and lies on top of a northwards countercurrent called the Leeuwin Undercurrent.
The Leeuwin Current is very different from the cooler, equatorward flowing currents found along coasts at equivalent latitudes such as the southwest African Coast (the Benguela Current); the long Chile-Peru Coast (the Humboldt Current), where upwelling of cool nutrient-rich waters from below the surface results in some of the most productive fisheries; the California Current, which brings foggy conditions to San Francisco; or the cool Canary current of North Africa.
Because of the Leeuwin Current, the continental shelf waters of Western Australia are warmer in winter and cooler in summer than the corresponding regions off the other continents. The Leeuwin Current is also responsible for the presence of the most southerly true corals at the Abrolhos Islands and the transport of tropical marine species down the west coast and across into the Great Australian Bight.
The ‘core’ of the Leeuwin Current can generally be detected as a peak in the surface temperature with a strong temperature decrease further offshore. The surface temperature difference across the Current is about 1 °C at North West Cape, 2° to 3° at Fremantle and can be over 4° off Albany in the Great Australian Bight. The current frequently breaks out to sea, forming both clockwise and anti-clockwise eddies.
The Leeuwin Current is influenced by El Niño conditions, characterised by slightly lower sea temperatures along the Western Australian coast and a weaker Leeuwin Current, with corresponding effects upon rainfall patterns.
The existence of the current was first suggested by William Saville-Kent in 1897. Saville-Kent noted the presence of warm tropical water offshore in the Houtman Abrolhos, making the water there in winter much warmer than inshore at the adjacent coast. The existence of the current was confirmed over the years, but not characterised and named until Cresswell and Golding did so in the 1980s.Namib
The Namib is a coastal desert in southern Africa. The name Namib is of Khoekhoegowab origin and means "vast place". According to the broadest definition, the Namib stretches for more than 2,000 kilometres (1,200 mi) along the Atlantic coasts of Angola, Namibia, and South Africa, extending southward from the Carunjamba River in Angola, through Namibia and to the Olifants River in Western Cape, South Africa. The Namib's northernmost portion, which extends 450 kilometres (280 mi) from the Angola-Namibia border, is known as Moçâmedes Desert, while its southern portion approaches the neighboring Kalahari Desert. From the Atlantic coast eastward, the Namib gradually ascends in elevation, reaching up to 200 kilometres (120 mi) inland to the foot of the Great Escarpment. Annual precipitation ranges from 2 millimetres (0.079 in) in the most arid regions to 200 millimetres (7.9 in) at the escarpment, making the Namib the only true desert in southern Africa. Having endured arid or semi-arid conditions for roughly 55–80 million years, the Namib may be the oldest desert in the world and contains some of the world's driest regions, with only western South America's Atacama Desert to challenge it for age and aridity benchmarks.
The desert geology consists of sand seas near the coast, while gravel plains and scattered mountain outcrops occur further inland. The sand dunes, some of which are 300 metres (980 ft) high and span 32 kilometres (20 mi) long, are the second largest in the world after the Badain Jaran Desert dunes in China. Temperatures along the coast are stable and generally range between 9–20 °C (48–68 °F) annually, while temperatures further inland are variable—summer daytime temperatures can exceed 45 °C (113 °F) while nights can be freezing. Fogs that originate offshore from the collision of the cold Benguela Current and warm air from the Hadley Cell create a fog belt that frequently envelops parts of the desert. Coastal regions can experience more than 180 days of thick fog a year. While this has proved a major hazard to ships—more than a thousand wrecks litter the Skeleton Coast—it is a vital source of moisture for desert life.
The Namib is almost completely uninhabited by humans except for several small settlements and indigenous pastoral groups, including the Ovahimba and Obatjimba Herero in the north, and the Topnaar Nama in the central region. Owing to its antiquity, the Namib may be home to more endemic species than any other desert in the world. Most of the desert wildlife is arthropods and other small animals that live on little water, although larger animals inhabit the northern regions. Near the coast, the cold ocean water is rich in fishery resources and supports populations of brown fur seals and shorebirds, which serve as prey for the Skeleton Coast's lions. Further inland, the Namib-Naukluft National Park, the largest game park in Africa, supports populations of African Bush Elephants, Mountain Zebras, and other large mammals. Although the outer Namib is largely barren of vegetation, lichens and succulents are found in coastal areas, while grasses, shrubs, and ephemeral plants thrive near the escarpment. A few types of trees are also able to survive the extremely arid climate.National Marine Aquarium of Namibia
The National Marine Aquarium of Namibia is an aquarium in Swakopmund, Namibia. The Aquarium features fauna from the cold Benguela Current in the southern Atlantic Ocean.RRS William Scoresby
RRS William Scoresby was British Royal Research Ship built for operations in Antarctic waters. Specially built for the Discovery Committee by Cook, Welton & Gemmell of Beverley, the ship was launched on 31 December 1925, and named after the noted 19th-century Arctic explorer, scientist and clergyman. Over the next 12 years the ship made seven voyages into Antarctic waters as part of the Discovery Investigations, accompanied by the ship Discovery until 1929, and then by Discovery II. During this time she marked about 3,000 whales and completed biological, hydrographical and oceanographic studies. She also took part in the 2nd Wilkins-Hearst Antarctic Expedition in 1929-1930, launching a Lockheed Vega floatplane for flights over Antarctica.Laid up in St Katharine Docks in 1938, she was the requisitioned by the Admiralty in October 1939 and converted into a minesweeper. Commissioned as HMS William Scoresby (J122) in June 1940 she was stationed in the Falkland Islands. In early 1944 she took part in Operation Tabarin, establishing British bases in Antarctica. The vessel was decommissioned in September 1946, and transferred to the newly formed National Institute of Oceanography in February 1951. She made one last voyage, surveying the Benguela Current off the west coast of Africa, before finally being sold for scrapping by the British Iron & Steel Corporation in 1954.Rondeletiola minor
Rondeletiola minor, also known as the lentil bobtail, is a species of bobtail squid native to the eastern Atlantic Ocean and Mediterranean Sea. Its natural range covers the northwest of Spain, Portugal, and the eastern, central and western Mediterranean Sea (including the Ligurian Sea, northern and southern Tyrrhenian Sea, Strait of Sicily, Gulf of Taranto,
Adriatic Sea, north Aegean Sea, Sea of Marmara, and Levantine Sea) to the southeastern Atlantic Benguela Current off Namibia.R. minor grows to a mantle length (ML) of 23 mm.The type specimen was collected in the Tyrrhenian Sea and is deposited at the Stazione Zoologica in Naples.Sataspes
Sataspes was a Persian navigator and cavalry commander whose name is derived from Sat (=100 sad) and Asp (= Horse, Asb). He is also credited with originating the term "horse latitudes".
Sataspes (who, according to Herodotus, was Xerxes I's cousin by his mother being Darius I's sister) had been condemned to death for kidnapping and raping Megabyzus's daughter. However his mother, Atossa, successfully convinced Xerxes to change the punishment to a more severe one - Sataspes was tasked to circumnavigate Africa. He took an Egyptian ship and crew, sailed through the Pillars of Hercules, and proceeded south for many months, but returned to Egypt without successfully completing his task. He claimed that at the farthest point he reached, he encountered a "dwarfish race, who wore a dress made from the palm tree", and that he was forced to return because his ship stopped and would not sail any further. Xerxes did not accept this excuse, and had him put to death. However, it has been suggested that Sataspes could have simply encountered the Benguela Current, which prevented him from sailing any farther.Skeleton Coast
The Skeleton Coast is the northern part of the Atlantic coast of Namibia and south of Angola from the Kunene River south to the Swakop River, although the name is sometimes used to describe the entire Namib Desert coast. The Bushmen of the Namibian interior called the region "The Land God Made in Anger", while Portuguese sailors once referred to it as "The Gates of Hell".
The name Skeleton Coast was coined by John Henry Marsh as the title for the book he wrote chronicling the shipwreck of the Dunedin Star. Since the book was first published in 1944, it has become so well known that the coast is now generally referred to as Skeleton Coast and is given that as its official name on most maps today.
On the coast, the upwelling of the cold Benguela current gives rise to dense ocean fogs (called cassimbo by the Angolans) for much of the year. The winds blow from land to sea, rainfall rarely exceeds 10 millimetres (0.39 in) annually and the climate is highly inhospitable. There is a constant, heavy surf on the beaches. In the days before engine-powered ships and boats, it was possible to get ashore through the surf but impossible to launch from the shore. The only way out was by going through a marsh hundreds of miles long and only accessible via a hot and arid desert.
The coast is largely soft sand occasionally interrupted by rocky outcrops. The southern section consists of gravel plains, while north of Terrace Bay the landscape is dominated by high sand dunes. Skeleton Bay is now known as a great location for surfing.South Atlantic Current
South Atlantic Current is an eastward ocean current, fed by the Brazil Current. That fraction of it which reaches the African coast feeds the Benguela Current. It is continuous with the northern edge of the Antarctic Circumpolar Current.
The seafaring is usually easier and thus safer in area of the South Atlantic Current than in the Antarctic Circumpolar Current, though also slower.Stoloteuthis leucoptera
Stoloteuthis leucoptera, also known as the butterfly bobtail squid, is a widespread species of bobtail squid. Its natural range covers the Atlantic Ocean, Mediterranean Sea, and southwestern Indian Ocean. It is distributed from the Gulf of St Lawrence to the Straits of Florida in the western Atlantic and in the Bay of Biscay in the eastern Atlantic. In the Mediterranean Sea, it is specifically found in the northern and southern Tyrrhenian Sea, Ligurian Sea, and off Gorgona Island. S. leucoptera has also been recorded from the Benguela Current off Namibia. There exist unverified records of specimens off eastern Tasmania.On average, females are slightly larger than males. They grow to 18 mm and 17 mm in mantle length, respectively.Succulent Karoo
The Succulent Karoo is a desert ecoregion of South Africa and Namibia.Thiomargarita
Thiomargarita is a genus (family Thiotrichaceae) which includes the vacuolate sulfur bacteria species Thiomargarita namibiensis, Candidatus Thiomargarita nelsonii, and Ca. Thiomargarita joergensii.
Representatives of this genus can be found in a variety of environments that are rich in hydrogen sulfide, including methane seeps, mud volcanoes, brine pools, and organic-rich sediments such as those found beneath the Benguela Current and Humboldt Current. These bacteria are generally considered to be chemolithotrophs that utilize reduced inorganic species of sulfur as metabolic electron donors to produce energy for the fixation of carbon into biomass. Carbon fixation occurs via the Calvin Benson Bassham cycle and possibly the reverse Krebs cycle.