+A permafrost-created a pingo or “ice pimple” in the North Slope of Alaska. Scientists from Sandia National Laboratories have been using a fiber optic cable to study permafrost in the Arctic seafloor to improve the understanding of global climate change. Credit: Sandia National Laboratories
The Arctic is remote, with often harsh conditions, and its climate is changing rapidly—warming four times faster than the rest of the Earth. This makes studying the Arctic climate both challenging and vital for understanding global climate change.
Scientists at Sandia National Laboratories are using an existing fiber optic cable off Oliktok Point on the North Slope of Alaska to study the conditions of the Arctic seafloor up to 20 miles from shore. Christian Stanciu, project lead, will present their latest findings on Friday, Dec. 15 at AGU’s Fall Meeting in San Francisco.
Their goal is to determine the seismic structure of miles of Arctic seafloor. Using an emerging technique, they can spot areas of the seafloor where sound travels faster than on the rest of the seafloor, typically because of more ice. They have identified several areas with lots of ice, said Stanciu, a Sandia geophysicist.
The scientists also used the cable to determine temperatures over the stretch of seafloor and monitored temperature changes over seasons. These data, unlike any collected before, were inserted into a computer model to infer the distribution of submarine permafrost, said Jennifer Frederick, a computational geoscientist.
“One of the innovations of this project is that we can now use a single fiber to get acoustic and temperature data,” Stanciu said. “We developed a new system to remotely collect both types of data using one fiber strand. We’re getting some interesting results.”
+Sandia National Laboratories researchers Michael Baker, Rob Abbott and Christian Stanciu, stand in front of the iced overBeaufort Sea on the North Slope of Alaska. By sending laser pulses down a fiber optic cable under the sea floor, the researchers study permafrost in the seafloor. Credit: Sandia National Laboratories
Permafrost and bouncing light
Like leftover roast turkey sitting in the back of the freezer since Thanksgiving, Arctic permafrost is a banquet just waiting to be thawed. Specifically, as the once-living matter that was frozen during the last ice age thaws, microbes begin to digest it and produce waste gases such as methane and carbon dioxide, Frederick said. Scientists are studying just how large a microbial banquet lies frozen in the Arctic and how large of an impact those gases could have on the global climate.
To study permafrost on the Arctic seafloor, the researchers used pulses of laser light shot down a submarine telecommunications fiber optic cable buried off the coast of Alaska, running north from Oliktok Point. Tiny imperfections in the cable caused light to bounce back to a sensor system.
By capturing this light at two wavelengths, or colors, and comparing them, the researchers could determine the temperature of the cable every yard,
