Cetaceans provide cheap labor in the icy deep. (Putting whales to work).

Polar scientists have recruited an unlikely pair to aid their exploration of freezing Arctic waters: two wild white whales. The data gathered by these cetacean assistants promise to bolster scientists' understanding of environmental conditions in the Arctic region, which climate modelers predict will be hard hit by global warming.

White whales, also known as belugas, live primarily in the Arctic Ocean and adjoining seas. In winter, the 3-to-5-meter-long whales frequent waters topped by ice. "The whales enabled us to get data from an area that would be more or less impossible to explore any other way," says oceanographer Ole Anders Nost of the Norwegian Polar Institute in Tromso.

Nost and his colleagues captured the whales--residents of the Storfjorden, Svalbard, Arctic fjord--and outfitted them with sensors designed to track their movements and relay the information via satellite. To measure ocean conditions, the team added temperature and salinity sensors to the devices. After the whales were released, the sensors sampled the water once per second each time the animals ascended from a dive. Researchers on shore received the data when the whales surfaced for air.

"We couldn't plan where the whales were going to go," Nost says. "It was lucky for us that they swam where the data was interesting."

Marine mammals naturally seek out temperature boundaries because they are prime feeding spots. That inclination led to a surprising discovery: Beneath the Arctic Ocean's ice-covered surface lies a tongue of warmer North Atlantic water. Scientists had thought that the entire water column is at or near the freezing point. The inflow of higher-temperature water could be part of a complex equation governing ice formation, the researchers report in an upcoming Geophysical Research Letters.

Information gathered by whales and other marine mammals could lead to improved climate models and enable researchers to separate natural short-term cycles in ocean conditions from longer-term change driven by global warming, the researchers suggest.

"It's fine data and a really novel approach," says physical oceanographer James H. Swift of the Scripps Institution of Oceanography in La Jolla, Calif. However, robotic underwater vehicles now under development (Electronic Jetsam) will also be able to access arctic waters, he notes, so the use of marine mammals as data collectors might be short-lived.

Or maybe not, says George W. Boehlert, an oceanographer at the Oregon State University Hatfield Marine Science Center in Newport. The oceans are vast, and a diverse set of approaches--including use of sensor-carrying animals--may be needed to understand changing conditions.