Giant Mud Waves Found on Arctic Sea Floor

Giant mud waves along the bottom of the Arctic Ocean are the latest mystery confronting polar researchers, according to news from Ohio State University (OSU).

Researchers discovered the waves of mud while taking sonar images of the Arctic Ocean sea floor during icebreaker expeditions in 2005 and 2007. The undulating piles of mud -- some nearly 100 feet across -- were created by currents along the ocean bottom. Such features are common along the sea floor in other parts of the world, but scientists previously believed the Arctic Ocean was too calm to create such structures.

"The mud waves could be caused by tidal fluctuations," said Leonid Polyak, a research scientist at OSU's Byrd Polar Research Center. "But that's really just speculation at this point."

The icebreakers' sonar systems, which provided images of sediment layers as far as 1,000 feet below the sea floor, also provided evidence that huge glaciers once flowed along the bottom of the Arctic Ocean. In some places, the ice flows were heavy enough to create gouges a half-mile deep along the sea floor. Sonar images of these areas show parallel grooves where the glaciers once flowed, and boulders and debris left behind when the undersea ice retreated.

The 2005 and 2007 research trips -- known respectively as the Healy-Oden Trans-Arctic Expedition (HOTRAX) and the Lomonosov Ridge off Greenland (LOMROG) expedition -- were both aimed at studying the Arctic Ocean sediment record to see how the region changed over time. Researchers hope the data they gathered will also help them better understand the Arctic's role in global climate systems.

In addition to the sonar images, scientists from both expeditions are also analyzing more than 1,000 feet of sediment cores pulled from the sea bottom. The cores are being kept in refrigerated storage at the Byrd Polar Research Center.

Researchers are now studying the cores to better understand the Arctic's past and present, including the cause of the sea floor mud waves.

"Frankly, we have so much material to go through, and we've only just started," Polyak said. "The goal is to establish a climate record in the sediments. To figure it out, we'll go through the cores centimeter by centimeter."

By unraveling what the Arctic looked like during warm periods in the past, scientists seek to gain a better grasp of what it might look like in the near future. Climate change is affecting the polar regions more than anywhere else right now, and this past summer saw record low sea ice coverage in the Arctic Ocean.

"Even a couple of years ago, we wouldn't have predicted that so little ice would cover the Arctic Ocean," Polyak said. "It really looks like we may be living in a completely different world 20 to 30 years from now, with no ice in the Arctic in summer at all."

Ohio State University, "Arctic Expeditions Find Giant Mud Waves, Glacier Tracks." URL: (http://researchnews.osu.edu/archive/mudwave.htm)