Benthic lander

Benthic landers are observational platforms that sit on the seabed or benthic zone to record physical, chemical or biological activity.[1] The landers are autonomous and have deployment durations from a few days (for biological studies) to several years (for physical oceanography studies).

Benthic landers come in a variety of shapes and sizes depending upon the instrumentation they carry, and are typically capable of working at any ocean depth.

Skaf and Closp shortly before a launch
Two Benthic landers are prepared for a deployment during the Five Deeps Expedition

See also

References

  1. ^ Freiwald, André; Roberts, J. Murray (2005). Cold-water Corals and Ecosystems. Springer. p. 485. ISBN 3-540-24136-1. Retrieved 2008-06-27.
BENGAL (project)

BENGAL was the acronym of the research project High-resolution temporal and spatial study of the BENthic biology and Geochemistry of a north-eastern Atlantic abyssal Locality. The project was funded through the EC MAST III program from 1996 to 1998 (EC contract MAS-3 950018).

The project was a three-year multidisciplinary study of the abyssal benthic boundary layer in the northeast Atlantic. The aim of BENGAL was to determine how the seabed community and the geochemistry of the sediments change seasonally in response to a highly seasonal input of organic matter from the overlying water column. It did this by organising an intensive sampling programme on 14 research cruises over a two-year period and using a range of observational techniques including time-series sediment traps, marine snow cameras, benthic lander systems, long-term moorings and time-lapse photography. The study area was located in the middle of the Porcupine Abyssal Plain at a water depth of about 4850 m, 270 km southwest of Ireland (central location: 48°50′N 16°30′W). The BENGAL project involved 17 partners from 9 European countries.

Bahama Banks

The Bahama Banks are the submerged carbonate platforms that make up much of the Bahama Archipelago. The term is usually applied in referring to either the Great Bahama Bank around Andros Island, or the Little Bahama Bank of Grand Bahama Island and Great Abaco, which are the largest of the platforms, and the Cay Sal Bank north of Cuba. The islands of these banks are politically part of the Bahamas. Other banks are the three banks of the Turks and Caicos Islands, namely the Caicos Bank of the Caicos Islands, the bank of the Turks Islands, and wholly submerged Mouchoir Bank. Further southeast are the equally wholly submerged Silver Bank and Navidad Bank north of the Dominican Republic.

Bathythermograph

The bathythermograph, or BT, also known as the Mechanical Bathythermograph, or MBT; is a small torpedo-shaped device that holds a temperature sensor and a transducer to detect changes in water temperature versus depth down to a depth of approximately 285 meters (935 feet). Lowered by a small winch on the ship into the water, the BT records pressure and temperature changes on a coated glass slide as it is dropped nearly freely through the water. While the instrument is being dropped, the wire is paid out until it reaches a predetermined depth, then a brake is applied and the BT is drawn back to the surface. Because the pressure is a function of depth (see Pascal's law), temperature measurements can be correlated with the depth at which they are recorded.

Cabled observatory

Cabled observatories are seabed oceanographic research platforms connected to the surface by undersea cables. Such cables supply both power and telecommunications to instruments. By removing the limitations of undersea power sources and sonar or RF communications, cabled observatories allow persistent study of underwater phenomena. A single cable can support multiple observation sites via individual "drops;" multiple or branching cables may then provide data in 2D or 3D.

The extent of coverage is limited by the high cost of laying dedicated undersea cable. Initial experiments used abandoned communications cables; efforts are in progress to extend observations at lower cost by accessing more such cables.

Despite their advantages, cabled observatories can (and do) relay compromised data to scientists, particularly when located in remote parts of the ocean. Factors such as instrumental malfunction and biofouling are often responsible for this. Systematic improvements, to lessen the impacts of such factors, are currently being studied by groups such as Ocean Networks Canada.

Carbonate platform

A carbonate platform is a sedimentary body which possesses topographic relief, and is composed of autochthonic calcareous deposits. Platform growth is mediated by sessile organisms whose skeletons build up the reef or by organisms (usually microbes) which induce carbonate precipitation through their metabolism. Therefore, carbonate platforms can not grow up everywhere: they are not present in places where limiting factors to the life of reef-building organisms exist. Such limiting factors are, among others: light, water temperature, transparency and pH-Value. For example, carbonate sedimentation along the Atlantic South American coasts takes place everywhere but at the mouth of the Amazon River, because of the intense turbidity of the water there. Spectacular examples of present-day carbonate platforms are the Bahama Banks under which the platform is roughly 8 km thick, the Yucatan Peninsula which is up to 2 km thick, the Florida platform, the platform on which the Great Barrier Reef is growing, and the Maldive atolls. All these carbonate platforms and their associated reefs are confined to tropical latitudes. Today's reefs are built mainly by scleractinian corals, but in the distant past other organisms, like archaeocyatha (during the Cambrian) or extinct cnidaria (tabulata and rugosa) were important reef builders.

Chinese oceanographic research ship Zhang Jian

Chinese oceanographic research ship Zhang Jian is a Chinese research ship designed by Shanghai Ocean University and built by the civilian owned Zhejiang TianShi Shipbuilding Co., Ltd. (浙江天时造船有限公司) in Wenling, instead of government-owned enterprise, as in most cases of the ships in Chinese service.Chinese research ship Zhang Jian is the newest research ship in China (as of 2015), and it is designed to have an endurance of 60 days before needing resupply. The ship is designed to be a multifunction ship capable of carrying out various missions that previously had to be performed by separate ships. The ship primarily functions as an oceanographic research ship, buyt it can also act as a dive tender, a salvage ship, a rescue ship, a tourist ship, and a mother ship for a deep-submergence vehicle. The ship will be used as a mother ship for a Rainbowfish class bathyscaphe.

The ship also carries other equipment for deep sea exploration, including an UUV and three benthic landers. Designed by the Shenyang Institute of Automation (SIA, 沈阳自动化研究所) of Chinese Academy of Sciences, the three benthic landers were originally to be capable of operating at the depth of 11000 meters. To avoid delays, this goal was modified with reduced requirements for the first benthic lander, which would use foreign components purchased abroad and have a maximum operational depth of 7000 meters. The 11000 meter operational depth of the original specification will be met by the second and third units. These will use completely indigenous components; development was to be completed in 2015. The first benthic lander begun sea trials in October 2014.

List of submarine volcanoes

A list of active and extinct submarine volcanoes and seamounts located under the world's oceans. There are estimated to be 40,000 to 55,000 seamounts in the global oceans. Almost all are not well-mapped and many may not have been identified at all. Most are unnamed and unexplored. This list is therefore confined to seamounts that are notable enough to have been named and/or explored.

Mooring (oceanography)

A mooring in oceanography is a collection of devices connected to a wire and anchored on the sea floor. It is the Eulerian way of measuring ocean currents, since a mooring is stationary at a fixed location. In contrast to that, the Lagrangian way measures the motion of an oceanographic drifter, the Lagrangian drifter.

Oceanic plateau

An oceanic or submarine plateau is a large, relatively flat elevation that is higher than the surrounding relief with one or more relatively steep sides.There are 184 oceanic plateaus covering an area of 18,486,600 km2 (7,137,700 sq mi), or about 5.11% of the oceans. The South Pacific region around Australia and New Zealand contains the greatest number of oceanic plateaus (see map).

Oceanic plateaus produced by large igneous provinces are often associated with hotspots, mantle plumes, and volcanic islands — such as Iceland, Hawaii, Cape Verde, and Kerguelen. The three largest plateaus, the Caribbean, Ontong Java, and Mid-Pacific Mountains, are located on thermal swells. Other oceanic plateaus, however, are made of rifted continental crust, for example Falkland Plateau, Lord Howe Rise, and parts of Kerguelen, Seychelles, and Arctic ridges.

Plateaus formed by large igneous provinces were formed by the equivalent of continental flood basalts such as the Deccan Traps in India and the Snake River Plain in the United States.

In contrast to continental flood basalts, most igneous oceanic plateaus erupt through young and thin (6–7 km (3.7–4.3 mi)) mafic or ultra-mafic crust and are therefore uncontaminated by felsic crust and representative for their mantle sources.

These plateaus often rise 2–3 km (1.2–1.9 mi) above the surrounding ocean floor and are more buoyant than oceanic crust. They therefore tend to withstand subduction, more-so when thick and when reaching subduction zones shortly after their formations. As a consequence, they tend to "dock" to continental margins and be preserved as accreted terranes. Such terranes are often better preserved than the exposed parts of continental flood basalts and are therefore a better record of large-scale volcanic eruptions throughout Earth's history. This "docking" also means that oceanic plateaus are important contributors to the growth of continental crust. Their formations often had a dramatic impact on global climate, such as the most recent plateaus formed, the three, large, Cretaceous oceanic plateaus in the Pacific and Indian Ocean: Ontong Java, Kerguelen, and Caribbean.

Outline of oceanography

The following outline is provided as an overview of and introduction to Oceanography.

Physical oceanography

Physical oceanography is the study of physical conditions and physical processes within the ocean, especially the motions and physical properties of ocean waters.

Physical oceanography is one of several sub-domains into which oceanography is divided. Others include biological, chemical and geological oceanography.

Physical oceanography may be subdivided into descriptive and dynamical physical oceanography.Descriptive physical oceanography seeks to research the ocean through observations and complex numerical models, which describe the fluid motions as precisely as possible.

Dynamical physical oceanography focuses primarily upon the processes that govern the motion of fluids with emphasis upon theoretical research and numerical models. These are part of the large field of Geophysical Fluid Dynamics (GFD) that is shared together with meteorology. GFD is a sub field of Fluid dynamics describing flows occurring on spatial and temporal scales that are greatly influenced by the Coriolis force.

Undersea mountain range

Undersea mountain ranges are mountain ranges that are mostly or entirely underwater, and specifically under the surface of an ocean. If originated from current tectonic forces, they are often referred to as a mid-ocean ridge. In contrast, if formed by past above-water volcanism, they are known as a seamount chain. The largest and best known undersea mountain range is a mid-ocean ridge, the Mid-Atlantic Ridge. It has been observed that, "similar to those on land, the undersea mountain ranges are the loci of frequent volcanic and earthquake activity".

Wave base

The wave base, in physical oceanography, is the maximum depth at which a water wave's passage causes significant water motion. For water depths deeper than the wave base, bottom sediments and the seafloor are no longer stirred by the wave motion above.

Waves
Circulation
Tides
Landforms
Plate
tectonics
Ocean zones
Sea level
Acoustics
Satellites
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