Alaska continental slope 100 miles farther out than thought
The foot of the continental slope off Alaska is more than 100 nautical miles farther from the U.S. coast than previously assumed, according to new Arctic sea floor data released today by the University of New Hampshire and the federal government.
The data could support U.S. rights to natural resources of the sea floor beyond the generally accepted limit of 200 nautical miles from the coast.
'We found evidence that the foot of the slope was much farther out than we thought. That was the big discovery,' said Dr. Larry Mayer, expedition chief scientist and co-director of the Joint Hydrographic Center at University of New Hampshire.
The Joint Hydrographic Center is a partnership between the university and the National Oceanic and Atmospheric Administration, NOAA.
The NOAA co-director, Andy Armstrong, also was co-chief scientist on the expedition. 'We now have a better geologic picture of what’s happening in that area of the Arctic,' Armstrong said.
The Arctic mapping expedition to the Chukchi Cap some 600 nautical miles north of Alaska was conducted between August 17 and September 15, 2007 aboard the U.S. Coast Guard Cutter Healy.
'Understanding the bathymetry and geological history of the Arctic is an important part of understanding global climate change,' said Mayer. 'The Arctic acts as a global spigot in controlling the flow of deep ocean currents that distribute the Earth’s heat and control climate. The Arctic is the canary in the coal mine.'
Scientists used sophisticated echo sounders to survey this little-known region, providing more detailed data and images than existed previously as they mapped about 5,000 linear nautical miles.
'These are valuable data for NOAA and the United States, and I’m pleased that we’re making them available for anyone to use,' Armstrong said. The data are available at the Joint Hydrographic Center website at: http://www.ccom-jhc.unh.edu
'The sea floor is full of mysteries, and beneath the Arctic ice cap those mysteries are even harder to reveal,' said Mayer. 'The kind of full-coverage, high-resolution mapping we do provides critical insight for meeting the criteria of the Law of the Sea Convention as well as the geologic history of the region.'
Prior to this work, the only seafloor mapping data available in the ice-covered Arctic came mostly from ice islands and helicopters. These sparse individual measurements produced low-resolution maps compared to the Joint Hydrographic Center’s mapping.
Any coastal nation has sovereign rights over the natural resources of its continental shelf, generally recognized to extend 200 nautical miles out from the coast.
The Law of the Sea Convention, an international treaty now under consideration in the U.S. Senate, provides nations an internationally recognized basis to extend their sea floor resource rights beyond the foot of the continental slope if they meet certain geological criteria backed up by scientific data.
The Bush administration supports approval of the treaty.
Sam Fuerst, a Durham, North Carolina high school teacher joined the crew of the USCG Healy to aid the the mapping of the seafloor in support of the Law of the Sea mapping program.
'We were able to map an area much larger than in the original cruise plan, covering almost 5,000 miles,' wrote Fuerst in his blog from onboard the ship as the expedition was winding up. 'The reason for this great success has been the lack of sea ice. What has been good for our project has been bad for the Arctic.'
'We have accumulated a lot of data about the base of the continental slope and how it seems to trace around the Chukchi Cap at about a depth of 3,800 meters. At this depth, there is a clear break between the slope and the flat lying abyssal plain sediments,' Fuerst wrote. 'This may make a convincing case for an extended United States continental margin.'
On September 13, 2007, shipboard blogger McKenzie Funk wrote about how warm the Arctic appeared.
'If big swells and open water sound more typical to the Pacific or Atlantic Oceans, then that's the sad new reality. The Arctic Ocean doesn't seem quite like the Arctic Ocean anymore. Thanks to a warming climate, the polar ice cap is melting away.'
'For much of this cruise, the chief scientists have been shocked at how little ice there is, and now we're told there's empirical proof of the melt. Last week, Pablo Clemente-Colón of the National Ice Center turned to me at the row of computers that serves as our Internet café and said it was official: sometime in late August, according to his center's satellite analysis, the polar ice cap reached its lowest extent in recorded history.'
'Some scientists now predict the summer Arctic will be ice-free by 2040. What does this mean for the animals that live on the ice? Nothing good,' Funk wrote.
'A few days ago, the USGS announced the results of a study about the polar bear, which may soon be listed as threatened under the Endangered Species Act. By the middle of the century, the report said, the worldwide polar-bear population estimated at 22,000 today will shrink by two thirds, and the few survivors will be clustered on or near the islands of the Canadian Arctic, just about the only solid ground they'll be able to find,' he wrote.
'Here on the Healy, we keep a tally of the bears we've seen: 22 so far. Which means we've seen perhaps a thousandth of the total population,' wrote Funk. 'Not all of the sightings have been uplifting. A few nights ago, a bunch of us were out on the back deck at 2 am to watch Pablo deploy one of his buoys. We were in fully open ocean, dozens of miles from the ice pack, in a sort of half-fog at what passes for dusk around here, when a 10 foot wide chunk of ice flowed past. It was visible for maybe 15 seconds - the only ice we'd seen for days. On it: a polar bear, just drifting wherever the ocean wanted to take him.'