It's a hard life for creatures that live at the bottom of the Beaufort Sea off the Yukon North Slope.

In some areas of the Beaufort, winter ice reaches all the way to the sea bottom. As the ice is pushed by winds, tides, and the forces of its own freezing, it scours the sea floor, wreaking havoc on the animals that live there.

In other areas, the sea ice stays clear of the sea bed, but cuts bottom-dwelling organisms off from the supply of food available during open-water season.

Alec Aitken wants to understand more about creatures that can survive such difficult conditions, and the processes that keep them going.

Aitken, a University of Saskatchewan geographer, is part of an international research team taking part in a year-long study of Canada's arctic seas.

The researchers involved in the multimillion-dollar Canadian Arctic Shelf Exchange Study (CASES) will be based aboard the Canadian icebreaker Franklin, which has been refitted as a research vessel.

The 12 months of the study voyage, from September 2003 to September 2004, are broken into nine "legs" involving different kinds of research and different researchers. The research team Aitken leads will be on board for six of those legs.

He and his colleagues and students will be spending their time digging up samples of the sea bed at about 20 stations situated across the Mackenzie Shelf and Amundsen Gulf.

The samples are taken with an instrument called a box core, Aitken explains.

"It's a large steel box. It's released from a winch on the ship and dropped to the sea floor."

The weight of the falling box drives it into the sea floor, trapping a cross-section of sediments and the organisms that live in them. The box and cross-section are hauled back up, and Aitken and his crew retrieve organisms from the top 20 centimetres of sediment.

Of course, it's not quite that simple or neat. The organisms are small, ranging from clams, snails, and marine worms to little creatures best seen through a microscope. And they're embedded in muck -- lots of it.

"The organisms are sieved out of the sediment, then they're weighed and put in preservative to be counted and identified later," says Aitken. "We're interested in what animals inhabit the sea floor, the size of their populations, and how much carbon is stored in their tissues."

"Between stations, you just sieve like crazy so you'll be ready for the next station."

The actual counting and identifying of organisms happens later, and it's a slow process. Aitken's team took its first set of samples almost a year ago.

"We've just got it sorted," he says. "It takes a while, especially the little guys."

One thing Aitken's research team is hoping to learn from the series of samples, taken at different times over the course of the year, is how life at the bottom of the sea varies with the seasons and with ice cover. Since the sea-bottom creatures are a food source for other marine animals like fish and sea mammals, variations in life on the sea floor affect life higher up in the ocean too.

The research projects aboard the Franklin will also be looking at how much carbon is stored in the sediments and animal tissues of the sea bed, and how that changes with the seasons and the extent of sea ice.

Understanding the processes that govern whether carbon is stored in the organisms and sediments or released into the atmosphere in the form of carbon dioxide is important to our ability to predict how global climate change might affect the Arctic, says Aitken.

Carbon dioxide is one of the greenhouse gases recognized as a factor in the current worldwide warming trend.

"If less carbon is stored in the Arctic Ocean than is released, then we have a problem," he says.

The research into sea-bed organisms in the Beaufort is only one part of the work that will be done on the Franklin over the next year. For detailed information, go to the CASES website at www.cases.quebec-ocean.ulaval.ca.