Climate scientists hoping to collect data about fluctuating sea temperatures in the inaccessible and icy waters of Baffin Bay have enlisted the aid of some unconventional interns: narwhals.

Arctic waters like those in Baffin Bay represent an embarrassing data hole for researchers hoping to better predict and monitor the effects of global warming. Harsh winters make measuring temperatures in the Bay's depths an impossibility, and researchers are typically forced to make loose estimates from data collected at small coastal settlements which are often far apart from one another. 

So when marine biologist Kristin Laidre, a researcher from the University of Washington, offered to share temperature data collected during her biological study of narwhals, climate scientists jumped at the chance, reports Nature.

"The animals have what we call high site fidelity," Laidre said. "We can catch some during summer, instrument them, and have a pretty good idea where they're going to go during winter."

In all, 14 narwhals were strapped with thermometers and satellite transmitters for the study. Throughout the winter, the unusual tusked marine mammals gave the most comprehensive coverage of the bay ever recorded, occasionally even diving to depths as deep as 1,773 meters.

The results were alarming. After combining the data from the narwhals with a series of samples taken from a helicopter and a ship in the spring of 2007, researchers discovered that waters in the center of Baffin Bay were about 0.9 °C warmer than previous estimates had suggested.

"It's always exciting to fill in a gap," said oceanographer Mike Steele, who co-authored the study, "but to find warming was not surprising."

Understanding the fluctuating temperatures in Baffin Bay and other Arctic waters in the region are important because they allow climate scientists to make better climate models. The region's pack ice, which includes Greenland's extensive ice cover, is in danger of collapsing if global temperatures continue to rise.

Scientists said they hope narwhals can continue to supply valuable data going forward, and Laidre is already envisioning ways to improve future studies.

"We were a little constrained as to how large an instrument we want to put on a narwhal," she said. "But if we were to continue this in the future we would like to talk more to oceanographers about what they need — for example salinity measurements."