MAR-ECO component projects
Nekton are mobile animals that can swim against currents, e.g. fishes, cephalopods, large crustaceans, and even whales. We know very little about the nektonic species living in the water column of the blue ocean waters, and especially at depths beyond 1000 m.
- Who are they, and how are they distributed?
- Do they aggregate around topographic and hydrographic features?
- How much daily vertical migration is there?
- What are the feeding patterns of the different species?
- How do they interact?
- What are their reproductive strategies?
Demersal nekton are mobile animal species living near or on the seabed. Most species are widely distributed across the Atlantic. With different shapes and sizes, they have fascinating life histories and ecological adaptations. Some species, primarily fishes, are being harvested by deep-sea trawlers and longliners. However, most of the species have life history features that are incompatible with high exploitation rates.
- Many are long-lived. (Some, such as the orange roughy, may live to be over a hundred years old, perhaps even more than 150 years)
- Most deep-sea species mature late and have low fecundities; hence their reproductive capacity is limited
- Growth rates tend to be slow and natural mortalities low
Much more information about deep-sea species is needed before researchers assume an advisory role for the management of deep-sea fisheries resources. Specific questions include:
- Do the members of given species inhabit different habitats at different ages?
- Do fish seek out specific topographical features (near to currents, in the lee of geographic features etc)?
- What kinds of communities exist in areas of soft or hard bottoms? Are there latitudinal differences?
Planktonic animals drift with the ocean currents and have limited mobility. Light drives photosynthesis and the production of microscopic plants, the food of minute animals living near the surface. However, light penetration and plant production decreases exponentially with depth, so how is energy conveyed to organisms living in the water column of deeper waters?
Epibenthos are animals living on or immediately above the seafloor. Some are attached to the substrate, others are mobile. Examples are sponges, corals and seastars.
A particularly interesting mobile group is the sea cucumbers which have swimming representatives in the deep-sea. Photographic images from submersibles used by MAR-ECO provide new insight and discoveries.
Studies of DNA can be used to characterize species, and delineate populations, and MAR-ECO will use modern molecular techniques to address several questions:
- Are the populations of a species inhabiting different parts of the mid-Atlantic Ridge distinct?
- Are they inter-related via "stepping stone" migration patterns?
- How do climate and current patterns influence diversity and dispersal patterns?
- Do thermal boundaries, such as the sub-polar front, restrict gene flow?
Researchers have developed kits that have been sent to researchers around the Atlantic. They have already collected many samples from a broad geographic range for a number of different fish species.
To adopt appropriate tools (technologies), procedures and strategies is critical for the success / failure of a research expedition.
Research vessels from several nations have been committed to MAR-ECO, equipped with the latest generation of modern technology. A core effort in the project is a two-month international cruise on Norway’s newest research vessel, the RV “G.O.Sars”, in 2004.
The project is collaborating with industry partners to develop and test new technologies. Kongsberg SIMRAD is providing major in-kind support, including the development of specialised moored instrument packages.
Video documentation of deep-sea and fragile marine life forms is of critical importance. MAR-ECO will use Remotely Operated Vehicles (ROVs) capable of operating at depth to observe, film, and sample organisms in the water columns and near the bottom.
A range of towed and lowered instruments and sampling devices will be used to observe and collect biological material, including also traditional fishing gears such as trawls, longlines and traps adapted for deep-sea use.
Mammals and seabirds
Whales and seabirds utilize oceanic plankton and nekton as food and may congregate in productive frontal zones and around topographic features. Researchers plan to conduct visual surveys of the large-scale migration patterns of whales and seabirds during the MAR-ECO cruises.