This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: They live in some of the most inaccessible waters on Earth, where ocean temperatures hover around freezing. Because they move through areas that humans rarely reach, they have been able to help researchers with a special task.
Equipped with sensors, six narwhals from the Scoresby Sound region, the world's largest fjord system on Greenland's east coast, collected data during their natural movements. This provided researchers from the University of Copenhagen, the Greenland Institute of Natural Resources and other institutions with entirely new data that would otherwise have been impossible to obtain. "The narwhals have been in parts of the fjords where very few measurements have been taken before.
And there, 300 kilometers (186 miles) from the coast, we find traces of Atlantic water. It is completely new that we can show this," says Mads Peter Heide-Jørgensen, professor at the Greenland Institute of Natural Resources. The water in the fjord system is a mixture of cold Polar Water originating in the Arctic and warmer, more saline Atlantic Intermediate Water from the Atlantic Ocean.
But the region has long been one of the major blind spots on the oceanographic map. Where research vessels often must turn back, narwhals can continue swimming. "Now we suddenly have measurements from places we can use in our models, giving us a much more complete picture of the ocean.
It is absolutely fantastic to use the animals in this way," says Susanne Ditlevsen, professor at the Department of Mathematical Sciences. In the study, which was published in the journal Science Advances, the researchers combined the narwhal measurements with historical oceanographic data from the World Ocean Database (WOD) for the Scoresby Sound region. "We used the two large data sets to build a robust model showing how temperature, salinity and depth are related.
The models show that the layer consisting of Atlantic water has become thicker, while the upper layer of Polar Water has become thinner," Ditlevsen says. The researchers show that warm Atlantic Intermediate Water now reaches deep basins in front of glaciers hundreds of kilometers into the fjord systems. "This is the water that helps melt the glaciers.
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