Deep-Diving Seals Are Cheap Labor for Antarctic Surveys

August 12, 2008

Sensor-equipped elephant seals are helping scientists survey the ice-covered oceans surrounding Antarctica—and in some ways the animals do a better—and cheaper—job than traditional methods.

Scientists typically collect data about Antarctica's waters using satellites, buoyant floats, and ship expeditions.

But during the winter, increased amounts of sea ice renders the region virtually impermeable to all three.

Using tagged elephant seals, researchers collected 30 times more data about the sea ice in oceans off Antarctica than was possible using conventional methods.

"This is the first study to look at the entire [ocean off Antarctica] and to show the scale over which these kinds of data can be collected," said study team member Daniel Costa, a marine biologist at the University of California, Santa Cruz.

(Watch streaming video of elephant seals on the Seal Cam.)

The research appears this week in the Proceedings of the National Academy of Sciences.

Living Submarines

Costa and his colleagues attached electronic sensor tags to 58 southern elephant seals wintering in Antarctica.

The tags—each about the size of a remote garage-door opener—measured temperature, pressure, salinity, and the animals' positions when they surfaced.

The data was beamed to a satellite and then relayed to researchers.

The tags, which were glued to the seals' heads using epoxy while the animals were anesthetized, remained attached for several months before falling off during seasonal sheddings.

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