'Unicorn' Whales Track Arctic Temperatures

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It’s no secret that the proverbial canary in the climate change mine is the Arctic. As National Oceanic and Atmospheric Administration (NOAA) administrator Jane Lubchenco noted when her organization launched its annual Arctic Report Card last week,“To quote one of my NOAA colleagues, ‘whatever is going to happen in the rest of the world happens first, and to the greatest extent, in the Arctic.’”

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But, even as the Arctic warms, seemingly irrevocably, it is still a formidable environment in which to operate, particularly in the winter. The coasts of Greenland, in particular, act as pathways for ice from the Arctic Ocean, as a result of which winter research expeditions can require icebreaking vessels that cost millions of dollars to charter.

Consequently, in some areas, such as Baffin Bay, a large area between northeast Canada and southwest Greenland, winter data have been scarce — or, in the words of Mike Steele of the University of Washington, “there was this gigantic, embarrassing hole.”

That hole is now being filled – thanks to narwhals, medium-size whales, endemic to the Arctic, known as unicorns of the seas because of the single, spiralling tusk found in males.

In a paper just published in the Journal of Geophysical Research -Oceans, Steele and other researchers, led by Kristin Laidre, also of the University of Washington, described tagging narwhals with satellite sensors that recorded ocean depths and temperatures during feeding dives from the surface pack ice to the seafloor, as deep as 1,773 meters, or more than a mile.

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In total, 14 adult narwhals were tagged with sensors. The data were automatically sent to a satellite when the narwhals surfaced for air between cracks in the sea ice. Tagging was carried out in accordance with the University of Washington’s Animal Care Guidelines and a permit issued by the Government of Greenland. Each sensor tag provided up to seven months of data before falling off.

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Previously, winter temperature estimates in Baffin Bay were based on climatology data gathered from small settlements on both coasts. That data provided an estimated average winter temperature in southern Baffin Bay of about 3.3 degrees C (37.9 F). Data from the narwhals, however, showed that the temperatures in the bay were in fact warmer — between 4 and 4.6 degrees C (39.2 – 40.3 degrees F).

“Narwhals proved to be highly efficient and cost-effective ‘biological oceanographers,’ providing wintertime data to fill gaps in our understanding of this important ocean area,” said Laidre.

“It’s always nice to fill in a gap,” added Steele, who said that the new data, and data collected from possible future narwhal-centric missions, may help make future climate models of the region more accurate.

Top Image: Narwhals breaching through a polynya, or hole in the sea ice. Glenn Williams/National Institute of Standards and Technology.

Lower Image: Narwhal being affixed with a satellite transmitter. Kristin Laidre/NOAA