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The Antarctic Technology Offshore Lagoon Laboratory (ATOLL) was a floating oceanographic laboratory for in situ observation experiments. This facility also tested instruments and equipment for polar expeditions. The ATOLL hull was the largest fiberglass structure ever built at that time. [1] It was in operation from 1982 to 1995.
The ATOLL was composed of three curved fiberglass elements, each 25 m (82 ft) long and having a draught of only 38 cm (15 in). For towing, the elements could be assembled in a long S-shape; in operation, the elements would form a horseshoe shape surrounding 150 m2 (1,615 sq ft) water surface. The lab provided ample space for twelve researchers. The laboratory contained a lab, storage and supply facilities, a dormitory, computer room, and a fireplace.
The laboratory was installed and operated in the Baltic Sea (and the Bay of Kiel in particular) at the initiative and under the direction of Uwe Kils, at the Institute of Oceanography (Institut für Meereskunde) of the University of Kiel. The fiberglass hulls themselves were bought from Waki Zöllner's "Atoll" company. [2]
The onboard computer was a NeXT and the first versions of a virtual microscope of Antarctic krill for interactive dives into their morphology and behavior were developed here, finding later mention in Science magazine. The lab was connected to the Internet via a radio link, and the first images of ocean critters on the internet came from this NeXT. The first ever in situ videos of Atlantic herring feeding on copepods were recorded from this lab.
An underwater observation and experimentation room allowed direct observation and manipulation through large portholes.
The technical equipment included an ultra-high-resolution scanning sonar [3] that was used for locating schools of juvenile herring, for guiding a ROV, which was controlled via a cyberhelmet and glove, and for determining positions, distances, and speeds. Probes measured the water salinity, temperature, and oxygen levels. Special instruments could measure plankton-, particle-, and bubble-concentrations and their size distributions. [4] Imaging equipment included low-light still and high speed video cameras using shuttered Laser-sheet or infrared LED illumination. [5] An endoscope-system for non-invasive optical measurements called ecoSCOPE, which could also be mounted on an ROV, was developed and used to record the microscale dynamics and behavior of the highly evasive herring.
Scientific investigations aboard the ATOLL concentrated on one of the most important food chain transitions: the linkages between the early life stages of herring (Clupea harengus) and their principal prey, the copepods. A major hypotheses of fisheries ecologists is that the microdistribution of prey, the microturbulence of the ocean, or the retention conditions are normally not suited to allow strong year classes of fish to develop. In most years more than 99% of herring larvae do not survive.[ citation needed ] Occasionally however, physical and biotic conditions are favorable, larval survival is high, and large year-classes result. Research work at the ATOLL investigated the effects of small-scale dynamics on fish feeding and predator avoidance and their correlation to year-class strength.
Research questions investigated by students during courses and their thesis work at the Laboratory included: What are the effects of the natural light gradient on predator-prey interactions? How can the predator best see the prey without being seen? [6] How does the focussing of small waves oscillating light regime influence camouflage and attack strategy? What are the influences of the different frequencies of microturbulences? How do such effects change at the moment when herring larvae join into schools? What role does the phenomenon of aggregation play? Do ocean physics create or alter organism-aggregations? Can the dynamics of aggregations effect ocean physics at the microscales? [7] Are there effects of the surface waves? What are the distribution and dynamics of microbubbles caused by turbulences and gas-oversaturations? How can the organisms orient in respect to micro-gradients of the ocean physics? How do they survive in the direct vicinity of undulating anoxia and hypoxia? [8] Why are eelpouts, sticklebacks and herrings so extremely successful in the Baltic while cod is not? [9] What are the effects and functions of schooling for feeding and microscale-orientation? What is the behavior of fish in netcages and how much food is lost from the cages. [3] The ATOLL mainly served as a test bed for the development and field testing of equipment such as developing ROVs [10] that were to be used later in Antarctic expeditions, e.g. for in situ imaging of transparent organisms of krill size under the ice.
Antarctic krill is a species of krill found in the Antarctic waters of the Southern Ocean. It is a small, swimming crustacean that lives in large schools, called swarms, sometimes reaching densities of 10,000–30,000 individual animals per cubic metre. It feeds directly on minute phytoplankton, thereby using the primary production energy that the phytoplankton originally derived from the sun in order to sustain their pelagic life cycle. It grows to a length of 6 centimetres (2.4 in), weighs up to 2 grams (0.071 oz), and can live for up to six years. It is a key species in the Antarctic ecosystem and in terms of biomass, is one of the most abundant animal species on the planet – approximately 500 million metric tons.
Herring are forage fish, mostly belonging to the family of Clupeidae.
Atlantic herring is a herring in the family Clupeidae. It is one of the most abundant fish species in the world. Atlantic herrings can be found on both sides of the Atlantic Ocean, congregating in large schools. They can grow up to 45 centimetres (18 in) in length and weigh up to 1.1 kilograms (2.4 lb). They feed on copepods, krill and small fish, while their natural predators are seals, whales, cod and other larger fish.
Krill are small and exclusively marine crustaceans of the order Euphausiacea, found in all the world's oceans. The name "krill" comes from the Norwegian word krill, meaning "small fry of fish", which is also often attributed to species of fish.
The crabeater seal, also known as the krill-eater seal, is a true seal with a circumpolar distribution around the coast of Antarctica. They are medium- to large-sized, relatively slender and pale-colored, found primarily on the free-floating pack ice that extends seasonally out from the Antarctic coast, which they use as a platform for resting, mating, social aggregation and accessing their prey. They are by far the most abundant seal species in the world. While population estimates are uncertain, there are at least 7 million and possibly as many as 75 million individuals. This success of this species is due to its specialized predation on the abundant Antarctic krill of the Southern Ocean, for which it has uniquely adapted, sieve-like tooth structure. Indeed, its scientific name, translated as "lobe-toothed (lobodon) crab eater (carcinophaga)", refers specifically to the finely lobed teeth adapted to filtering their small crustacean prey. Despite its name, crabeater seals do not eat crabs. As well as being an important krill predator, the crabeater seal's pups are an important component of the diet of leopard seals. They are the only member of the genus Lobodon.
The ecoSCOPE is an optical sensor system, deployed from a small remotely operated vehicle (ROV) or fibre optic cable, to investigate behavior and microdistribution of small organisms in the ocean.
Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feeding are clams, krill, sponges, baleen whales, and many fish. Some birds, such as flamingos and certain species of duck, are also filter feeders. Filter feeders can play an important role in clarifying water, and are therefore considered ecosystem engineers. They are also important in bioaccumulation and, as a result, as indicator organisms.
The leopard seal, also referred to as the sea leopard, is the second largest species of seal in the Antarctic. Its only natural predator is the orca. It feeds on a wide range of prey including cephalopods, other pinnipeds, krill, fish, and birds, particularly penguins. It is the only species in the genus Hydrurga. Its closest relatives are the Ross seal, the crabeater seal and the Weddell seal, which together are known as the tribe of Lobodontini seals. The name hydrurga means "water worker" and leptonyx is the Greek for "thin-clawed".
The Antarctic fur seal, is one of eight seals in the genus Arctocephalus, and one of nine fur seals in the subfamily Arctocephalinae. Despite what its name suggests, the Antarctic fur seal is mostly distributed in Subantarctic islands and its scientific name is thought to have come from the German vessel SMS Gazelle, which was the first to collect specimens of this species from Kerguelen Islands.
Uwe Kils is a German marine biologist specializing in Antarctic biology.
Moroteuthopsis longimana, also known as the giant warty squid or longarm octopus squid, is a large species of hooked squid. It attains a mantle length of at least 85 cm and probably over 1.15 m. The largest complete specimen of this species, measuring 2.3 m in total length, was found in Antarctica in 2000.
Forage fish, also called prey fish or bait fish, are small pelagic fish which are preyed on by larger predators for food. Predators include other larger fish, seabirds and marine mammals. Typical ocean forage fish feed near the base of the food chain on plankton, often by filter feeding. They include particularly fishes of the order Clupeiformes, but also other small fish, including halfbeaks, silversides, smelt such as capelin and goldband fusiliers.
In biology, any group of fish that stay together for social reasons are shoaling, and if the group is swimming in the same direction in a coordinated manner, they are schooling. In common usage, the terms are sometimes used rather loosely. About one quarter of fish species shoal all their lives, and about one half shoal for part of their lives.
The true seal tribe Lobodontini, collectively known as the Antarctic seals or lobodontin seals, consist of four species of seals in four genera: the crabeater seal, the leopard seal, the Weddell seal, and the Ross seal. All lobodontine seals have circumpolar distributions surrounding Antarctica. They include both the world's most abundant seal and the only predominantly mammal-eating seal. While the Weddell seal prefers the shore-fast ice, the other species live primarily on and around the off-shore pack ice. Thus, though they are collectively the most abundant group of seals in the world, the combination of remote range and inaccessible habitat make them among the least well studied of the world's seals.
A bait ball, or baitball, occurs when small fish swarm in a tightly packed spherical formation about a common centre. It is a last-ditch defensive measure adopted by small schooling fish when they are threatened by predators. Small schooling fish are eaten by many types of predators, and for this reason they are called bait fish or forage fish.
Bettina Meyer is a German Antarctic researcher, best known for her work on the ecology and physiology of invertebrates in the pelagic zone. She is the head of the ecophysiology of pelagic key species working group at the Alfred Wegener Institute for Polar and Marine Research (AWI).
A metachronal swimming or metachronal rowing is the swimming technique used by animals with multiple pairs of swimming legs. In this technique, appendages are sequentially stroked in a back-to-front wave moving along the animal’s body. In literature, while metachronal rhythm or metachronal wave usually refer to the movement of cilia; metachronal coordination, metachronal beating, metachronal swimming or metachronal rowing usually refer to the leg movement of arthropods, such as mantis shrimp, copepods, antarctic krill etc. though all of them refer to the similar locomotion pattern.
A micronekton is a group of organisms of 2 to 20 cm in size which are able to swim independently of ocean currents. The word 'nekton' is derived from the Greek νήκτον, translit. nekton, meaning "to swim", and was coined by Ernst Haeckel in 1890.
Kendra Lee Daly is an oceanographer known for her work on zooplankton, particularly in low oxygen regions of the ocean. She is a professor at the University of South Florida, and an elected fellow of the American Association for the Advancement of Science.
Callianira antarctica is a species of ctenophore that physically resembles Mertensia ovum, but lacks the oil sacs. Just like other ctenophores, over 95% of its body mass and composition is water.
