Amundsen to use sonar to map Lancaster Sound this week

Amundsen feeds into on-board computers as it maps the sea floor using sound waves. (PHOTO BY JANE GEORGE)”/>
The sonar equipment on this barge launched from the Amundsen feeds into on-board computers as it maps the sea floor using sound waves. (PHOTO BY JANE GEORGE)

Amundsen, en route to a fiord north of Clyde River, where researchers did undersea mapping work using sonar. Sonar equipment emits sound waves that are similar to, but less powerful than the sounds emitted by seismic air guns. Researchers say they information they gather will be used for mapping, and could also be used by the oil and gas industry/ (PHOTO BY JANE GEORGE)”/>
The Amundsen, en route to a fiord north of Clyde River, where researchers did undersea mapping work using sonar. Sonar equipment emits sound waves that are similar to, but less powerful than the sounds emitted by seismic air guns. Researchers say they information they gather will be used for mapping, and could also be used by the oil and gas industry/ (PHOTO BY JANE GEORGE)

ON BOARD THE AMUNDSEN — If you’re the captain of an icebreaker like the Amundsen, you want to know where you’re going.

But most Arctic waterways are poorly mapped — and this means most marine traffic sticks to the same narrow shipping lanes over and over again.

To upgrade these navigation maps, researchers on board the Amundsen are using sonar waves — similar to, but less powerful than the sound waves emitted during seismic testing — to see what lies below the ocean and produce an image of the seabed.

Since the Amundsen left Quebec City five weeks ago, its sonar equipment, which produces audible chirps and pings as sound waves hit the sea floor and bounce back up, has been running continuously.

The icebreaker plans to map Lancaster Sound on Aug. 6.

There, the Amundsen’s multi-beam sonar machine will send out hundreds of sound waves covering about two kilometres on either side.

Like an ultrasound image of a baby in utero, the sonar waves produce detailed images down through the water to the sea floor.

The Amundsen also carries a single-beam sonar device attached to the bottom of its hull that can penetrate 100 metres below the sea floor.

Although the kind of sound waves the apparatus emits are similar to those sent out during seismic testing, they’re not as forceful and don’t go as far below the surface of the earth.

Still, the Amundsen’s mapping in Lancaster Sound is expected to reveal information about the sea floor and sediment distribution.

It may also provide clues thatshow where there may be gas deposits, if the sonar detects a natural leakage of gas from below the sea floor.

But the main goal of the mapping is to increase ship safety, says James Muggah, a researcher with the University of New Brunswick’s ocean mapping project.

Recent mapping in the Coronation Gulf near Kugluktuk found a new, southerly shipping lane that is safe for shipping, he says.

Improved mapping could also support Canada’s claim to the Northwest Passage, Muggah says.

The mapping will also help support Canada’s claim under the United Nations Convention on the Law of the Sea for rights over the North Pole and parts of the Arctic Ocean.

And mapping can also show where there’s been damage done by trawlers, and can be useful in dividing up fishery licenses or showing where fish stocks may be located, he said.

According to a description of the mapping project, oil and gas developers are also likely to make use of the mapping work that the Amundsen is doing this week.

“Canada has potentially huge economic benefits to gain by having access to the natural resources of the Arctic Archipelago region. Exploitation in this manner however, can only proceed in a safe and responsible manner, by managing the potential detrimental impacts to the environment,” says the mapping project description.

Before developing oil or gas, mapping has to be done “to assess potential natural hazards that might result in harmful affects both to persons and the environment.”

These hazards include underwater landslides and the impacts of glacial and sea ice.

The Amundsen’s trip across the Lancaster Sound will also collect information, among other things, about the water’s temperature and salt content by dragging a trailer, nicknamed “the fish,” off the back of the ship.

The impact of the mapping on marine mammals in Lancaster Sound will be little or none, says the Amundsen’s chief scientist, André Rochon, a marine geologist from the University of Rimouski.

But the results will prove useful in establishing a future marine protected area in Lancaster Sound.

“We need to know the shape, height and different features on the bottom to know what we’re protecting,” Rochon says.