In a research paper to be published online Saturday in the Journal of Geophysical Research, Oceans, scientists report that Baffin Bay off West Greenland has continued to warm since wintertime ocean temperatures were last able to be measured in the early 2000s.
And they used whales to measure the temperatures.
Using sensors tagged to narwhals –- a medium-sized, toothed whale -– the scientists were able to gather data that they had not been able to acquire for some time. The sensors recorded ocean depths and temperatures as the whales made successive vertical feeding dives from the pack ice above them to the ocean floor below.
The report found that the highest winter ocean temperature measurements during 2006 and 2007 ranged between 4 and 4.6 degrees Celsius (39.2 and 40.3 degrees Fahrenheit).
Sadly, these figures differ from previous climatology data; the temperatures were on average nearly a degree Celsius warmer, while the thickness of the winter surface isothermal layer was 50 to 80 meters less than it should have been.
“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 Kristin Laidre from the Polar Science Center in the University of Washington’s Applied Physics Laboratory. “Their natural behavior makes them ideal for obtaining ocean temperatures during repetitive deep vertical dives. This mission was a ‘proof-of-concept’ that narwhal-obtained data can be used to make large-scale hydrographic surveys in Baffin Bay and to extend the coverage of a historical database into the poorly sampled winter season.”
“Continued warming will likely have pronounced effects on the species and ecosystem in Baffin Bay and may eventually affect sea ice coverage in the region, which in recent years has already retreated significantly,” Laidre said, who was lead author of the paper and lead scientist on the NOAA-sponsored missions. “The timing of the break-up of spring sea ice is ecologically important for many marine species and is linked to primary production that forms the base of the food chain.”
Image Source: NOAA/University of Washington