(ORDO NEWS) — Japanese oceanographers have provided seals with sensors for water depth, temperature and conductivity to study hard-to-reach areas of the continental shelf. This made it possible to determine seasonal changes in the ecosystem of the shelf of East Antarctica and assess their biological effects.
The continental shelves of Antarctica are one of the most biologically productive regions of the World Ocean: due to the interaction of the ocean, sea ice and the ice shelf, a huge amount of biomass is produced in it. A special role in this process is played by deep warm streams coming from coastal areas, and coastal polynyas – areas of unfrozen sea water surrounded by ice.
Until now, scientists have not been able to fully study the seasonal dynamics of ocean circulation in the continental shelves, inaccessible to conventional research vessels. However, the scientists came to the aid of the Weddell seals that live on the fast ice – the sea ice frozen to the coast, which surrounds the polynya.
It turned out that CTD sensors can be attached to animals, which measure the electrical conductivity of water, its temperature and depth ( English conductivity, temperature, depth), and thus study hard-to-reach underwater areas. Using data from sensors, scientists can determine the origin of water flows at different depths and recreate their seasonal dynamics.
The researchers attached half-kilogram CTD sensors to eight seals living in eastern Queen Maud Land and western Endbury Land in East Antarctica. The testimony was taken from March to September in 2017.
It turned out that warm water with low salinity appears under the ice surface in the fall and goes deeper over time. In combination with meteorological and oceanographic modeling, scientists have shown that in the fall, an east wind causes a flow of warm surface waters from the shelf, and at the same time, possibly, additional production to the continental shelf. It also turned out that the warm water with low salinity encouraged the seals to search for food more actively.
Thus, data from Weddell seals have provided a description of the physical processes that increase the availability of prey in the Antarctic coastal marine ecosystem.
An article with the results of the study was published in the journal Limnology and Oceanography , dedicated to the study of inland waters and the ocean.
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