For three years, six Arctic travelers carried instruments into waters that research vessels could barely reach, exposing a worrying signal beneath the ice.
Narwhals, known as the “unicorns of the sea” because of their long spiral tusks, have helped scientists study changes in one of the most remote regions of the Arctic. Satellite transmitters were attached to six animals, and observations continued for three years.
According to CNN
The narwhals traveled along the coast of East Greenland and ventured into an extensive network of fjords – the largest in the world. The data collected showed that relatively warm, salty Atlantic water penetrates deep into the fjords. There, it erodes the glaciers from below and creates an additional threat to the ice sheet.
What data did the satellite transmitters collect?
Devices attached to the narwhals provided more than 2,000 measurements of water temperature and salinity between 2017 and 2020. The animals transmitted data even from hard-to-reach areas that research vessels can barely access.
Atlantic water was detected more than 290 kilometers from the coast.
Warm-water currents reached the glacier fronts and may have accelerated melting beneath the waterline.
The narwhals dove to depths of nearly 1,830 meters, exploring virtually the entire water column.
Winter measurements were especially important because it is dangerous for vessels to operate amid unstable sea ice during that season.
These findings are a serious cause for concern, as they point to the rapid melting of glaciers that flow into the sea.
– Eric Achterberg, professor at the Helmholtz Center for Ocean Research
East Greenland plays an important role in the planet’s climate system. Its glaciers discharge part of the ice sheet into the ocean, while local currents carry cold polar water southward toward the North Atlantic. These processes affect the distribution of freshwater and the health of marine ecosystems.
The region is also connected to the Atlantic Meridional Overturning Circulation – a large-scale system of ocean currents that influences weather and climate in different parts of the world. Scientists fear that its weakening or possible collapse could have serious consequences: rising sea levels along the U.S. coast, severe cooling in Europe, and droughts in Africa.
In many respects, East Greenland is an indicator of the climate changes that can be expected in the North Atlantic.
– Mads Peter Heide-Jørgensen, professor at the Greenland Institute of Natural Resources
Why were narwhals chosen for the observations?
The ocean in this region remains poorly studied because of its remoteness, harsh climate, and unpredictable ice conditions. Working in such conditions requires expensive icebreakers, whereas narwhals can travel through the fjords year-round.
The animals were caught by hunters, after which instruments weighing less than 450 grams were attached to them. The transmitters measured water temperature and salinity and sent the information via satellite. The researchers noted that the devices did not harm the narwhals.
The narwhals enabled us to obtain almost as many measurements in three years as humans had collected over the previous 130 years.
– Helen Coxall, professor at Stockholm University
Scientists refer to the penetration of warm, salty Atlantic water into Arctic seas as Atlantification. Observations of the narwhals showed that this process is already affecting the glaciers of East Greenland. At the same time, further long-term observations are needed to fully understand the scale of the changes taking place in the North Atlantic.