University of Alaska Fairbanks professor returns from seven week arctic expedition
FAIRBANKS, Alaska (KTVF) - A University of Alaska Fairbanks (UAF) professor has recently returned from a seven week expedition into the Arctic Ocean.
According to Bernard Coakley, Professor of Geology and Geophysics with the UAF Geophysical Institute, his expedition had to jump over a number of hurdles in order to take place.
“I raised the money for it from the National Science Foundation,” Coakley explained. “I arranged for us to be on the Sikuliaq, the UAF research vessel. Also there was a lot of other heartburn associated with this cruise, largely because of COVID. We had to do a one week quarantine before we got onto the ship, with testing at the beginning of quarantine and at the end. You had to have two negative tests to be able to board the ship. The science party was about 20 people and everybody tested negative so we all were able to get on, and then we lived in the bubble on the ship for seven weeks.”
Coakley continued, “We also had to get visas for the two Danes who ran the equipment, and we had to go through the State Department and get what’s called a National Interest Exemption. If we hadn’t been able to get those guys, or we hadn’t been able to get the equipment, that cruise would not have happened. So it was all kind of teetering on a knife edge for awhile, but in the end it all worked out.”
However, nature itself presented its own set of challenges that caused obstacles for the research crew.
“My joke about this kind of thing is, ‘I’d rather be lucky than good,’ and I was lucky in many respects,” Coakley elaborated. “But the luck didn’t extend to the ice. The ice was much more extensive than I anticipated and it was harder and more continuous than I anticipated. There are broad areas up north of Alaska that were open water, just every year for the last ten, except for this year. These were the heaviest ice conditions probably in 15 years or maybe more. It’s still nothing compared to what the ice used to be back even in the late 80s and 90s, but it complicated both the progress that Sikuliaq was able to make in the ice. Sikuliaq is technically not an icebreaker. It’s a ship that can push through ice up to maybe a meter thick as long as the ice is uncompressed. If you start squeezing the ice it gets harder to break.”
Fortunately the researchers were able to access areas despite the ice thanks to the ship’s crew according to Coakley.
There are areas I wanted to go that we couldn’t get in,” Coakley continued. “We had to improvise - and another thing I say about arctic science is, ‘It’s always plan B, or plan C, or plan D,’ because you can say you’re going to do wonderful and amazing things... but in the end the ice will tell you what to do. They call these ships icebreakers but really they might better be called ice avoiders because they prefer to approach with more finesse rather than brute force. That’s because of fuel, fuel’s expense, and because some captains, not the captain on Sikuliaq, some captains seem to worry about scratching the paint. But the captain on Sikuliaq and the whole crew on Sikuliaq, I cannot possibly say enough good things about them. They were great, they were very supportive, and honestly we got into areas that I did not think, given the ice conditions, we’d be able to get into - and that’s because they were very good.”
The goal of the expedition was to learn the history of the Arctic Ocean north of Alaska and Canada. To accomplish this, the crew used equipment to omit various types of sound along the sea floor.
“For example we had a swath mapping system that maps the stripe at the bottom of the sea floor, four times the water depth under the ship as the ship moved forward,” Coakley explained. “That is at 30 kilohertz, 30 thousand cycles per second, and that high frequency will hit the seafloor but it won’t penetrate it - so we just get a reflection from the sea floor surface. The next instrument that we use is called a bottom profiler, and that emits energy in a range of 2.5 and 6.5 kilohertz that will penetrate the seafloor and get an image, you know, the velocity of the sediment changes - so a little bit of the energy is reflected back. If you are clever, then you can reconstruct an image of the sediments beneath the sea floor, and that’s the sub-bottom profiler, it’s called a TOPAS 18, it gives us an image down to about 50 meters, maybe 100 meters if the conditions are right.”
Of particular interest of the expedition were two geological features in the area - in particular their history and when they formed.
“The two big features there are the Chukchi Borderland which is a high standing block of continental crust,” Coakley said. “It’s continental. We know it is continental because it is high standing, and that is the only way you get high standing stuff out in the ocean.”
He continued, “And then there is the Canada Basin, which is a relatively deep water basin but it is not your grandfather’s ocean basin. It seems that there is a fairly narrow base of strip of what we would call oceanic crust, like you get in the Atlantic or in the Pacific. Then there is a broader band of what appears to be a heavily deformed continental crust, and understanding the relationship between the oceanic crust, the very extended continental crust and the Chukchi Borderland is something that we are trying to do so that we can understand how that whole area formed.”
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