Double duty

Science World, Nov 13, 2006 by Sara Bennington

What can you learn from an elephant seal? For years, seals fitted with sensors have been beaming back information about their movements and diving behavior to researchers. Now, new seal sensors are also enabling marine biologist Dan Costa and colleagues to collect hard-to-get data on the ocean water.

In addition to recording how far and deep the seal swims, Costa's new high-tech sensors document ocean temperatures and salinity levels, or the amount of salt in the water. Changes in these characteristics affect how currents flow through ocean water. So by gathering this data from around the world, scientists can trace ocean circulation patterns.

Scientists have traditionally used buoys, ships, and submarines to gather this information. However, elephant seals regularly swim in places to which these devices can't go--including under the floating ice around Antarctica. Costa hopes that the roughly 10,000 ocean profiles collected by elephant seals each year will help researchers fill in these gaps.