Tagged Narwhals in Arctic Provide Key Winter Temperature Data

Scientists from the United States and Greenland have successfully used satellite tags on narwhals to measure rising ocean temperatures in Baffin Bay. In 2006 and 2007, the scientists outfitted 14 adult narwhals — medium-sized toothed Arctic whales — with satellite tags that recorded ocean temperatures, depths, and location and that transmitted that data to satellites whenever the whales surfaced between the ice in Baffin Bay, west of Greenland. The tags showed that the highest winter ocean temperatures ranged between 4 and 4.6 degrees Celsius (39.2 and 40.3 degrees Fahrenheit), which is nearly a degree Celsius warmer that previous human-collected data showed. The narwhal study, funded by the U.S. National Oceanic and Atmospheric Administration, also showed that the thickness of a stable layer of sea surface temperatures — which plays an important role in ocean circulation — was 50 to 80 meters thinner than reported in previous climatology data. Scientists said that the narwhals, which dove to a depth of 1,773 meters — more than a mile — provided vital data not only about warming sea temperatures but about possible effects on ocean circulation patterns.