Narwhals are toothed Arctic whales capable of deep dives. Scientists were able to attach sensors to the whales to record ocean depths and temperatures. Some of the narwhals dove deeper than one mile. The whales are able to swim and feed even during winter conditions in Baffin Bay near West Greenland, but scientists have more difficulty conducting their research then due to the increase in ice and harsh weather. So they hatched the plan to place sensors on the whales during winter and take measurements using a much easier method. Previously scientists had relied on long-term historical data based on averages, but not many direct measurements.
“Narwhals 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,” said Kristin Laidre from the Polar Science Center. (Source: NOAA.gov)
The new direct measurements coming from the whale-based sensors did help the scientists fill in gaps in their data. They found on average their ocean temperature measurements were almost a full degree greater than those in climatology data. Fourteen adult narwhals were tagged with the sensors which recorded date, time, depth, and temperature data. When the narwhals surfaced between sea ice to breathe, data from the sensors was transmitted to satellites. Sensors were tagged to the narwhals according to University of Washington guidelines which protect animals used in research. Each sensor collected up to seven months of data before falling off.
Narwhals in Baffin Bay were chosen because the area is significant for climate change research due to the large concentration of sea ice and marine mammals. Baffin Bay is over five hundred miles wide in some places. It is right next to Greenland where huge slabs of ice are breaking off and sliding into the ocean. Some of the slabs are so large they are referred to as islands, such as Petermann B 2010. This ice island, estimated to be 80 square kilometers, is big enough helicopters can land on it.
These gigantic slabs of ice are melting and releasing fresh water, disrupting the balance of fresh water and salt water, which blocks certain marine life from forming. They also can disrupt the food cycle, it is thought, by blocking sunlight plankton need to survive. Without plankton the narwhals and other species living there might not have enough food. The ice islands also scrape the ocean floor in some places dislocating clams, starfish, and whatever is in their paths. “All these organisms are very important food sources for animals like seal and whales or walrus,” said scientist Jean-Eric Tremblay. (Source: Nunatsiaqonline.ca)
Narwhals are known for their long tusks, which are actually teeth.
Image Credit: Public Domain