Friday, July 29, 2011

Narwhals contributing to mounting climate change data

While the major heat wave last week may only hint at the long term climate changes taking place on Earth, the indisputable evidence from around the world – especially in the Arctic – continues to mount.  Even narwhals have been used to collect climate data.
Photo by Paul Nicklen
University of Washington biologist Kristin Laidre has found a new and unusual use for what may be the narwhal’s greatest behavioral claim to fame – their incredible ability to dive to great depths.  In 2006 and 2007, Laidre successfully attached satellite transmitters to14 narwhals in Melville Bay on the west coast of Greenland, and in addition to collecting data on the animals’ geographic positioning, the tags also recorded the temperature of the water as they dived to the bottom.  While Laidre knew that temperature data would be somewhat insightful to her narwhal research, she also guessed that oceanographers and climatologists might find the data useful as well.  It is difficult to use traditional oceanographic measuring devices to monitor water temperatures at great depths, especially in the winter when the water is frozen over for many months.  As a result, researchers have little data from the middle of Baffin Bay to feed into their climate models.  Instead, they have used temperature readings from coastal locations or estimates calculated from historic data, which clearly provide only a hint of the true picture.
“The gliders that oceanographers occasionally use to collect this data sort of look like a streamlined narwhal, with a long pointy antenna, but they’re not as smart as narwhals because sometimes they can’t find the surface and get caught under the ice,” Laidre said. When the narwhal-collected temperature data was published in a scientific journal in 2010, it generated considerable media attention, not only for what oceanographers learned about water temperatures but also for the unusual way the data were collected.  Thanks to the narwhals, water temperatures were determined to be about 1.8 degrees F warmer than what the climate models predicted, and the surface isothermal layer – a layer of water that is at a constant temperature – was 160-260 feet thinner than previously believed.
“I’m not an oceanographer, but for me the excitement was the proof of concept -- that it worked and we collected useful data and the scientific community seemed to be interested in it,” Laidre added. “[The data] suggested that Baffin Bay has continued its warming trend, though I don’t know that it was terribly surprising to the oceanographers.”
Similar data is being collected by narwhals along the East Greenland coast this year.

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