Bitter cold and floating sea ice long frustrated scientists seeking to study the ocean around Antarctica in winter. The solution: Send in the seals.
The polar regions are expected to be especially sensitive to climate change, but collecting data has been a problem, especially in the wind-whipped Southern Ocean surrounding Antarctica.
So researchers led by Jean-Benoit Charrassin of the National Museum of Natural History in Paris decided to recruit help from residents of the area.
They glued electronic data-collecting equipment to 58 elephant seals that lived in the region. The animals can dive more than a mile deep in search of food.
The machines radioed back information on temperature, pressure, salinity and position whenever the seals surfaced.
The result: Nine times more data than had been previously available from buoys and ships and 30 times more information than had been known from beneath the winter sea ice, the researchers report in Tuesday's edition of Proceedings of the National Academy of Sciences.
Overall, the researchers obtained 16,500 water profiles from the seal-borne instruments, including 4,520 from beneath the sea ice.
With the information, the scientists are mapping the water properties of the Southern Ocean, including the main fronts where the properties of the water change.
They report that formation of sea ice peaked in April and May — early winter in the Southern Hemisphere.
Funding for the study was provided by government and research agencies in France, Australia, the United States and United Kingdom.