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.
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.
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).