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Yukon's largest lake gets a thorough biophysical

When University of Alberta graduate student Ellorie McKnight began working on her biology master's thesis project, her primary research focus was: "How are large northern lakes being affected by climate change?"

When University of Alberta graduate student Ellorie McKnight began working on her biology master’s thesis project, her primary research focus was: “How are large northern lakes being affected by climate change?” She planned to use Kluane Lake as her model system.

“That was the original question,” says McKnight, who embarked on her master’s quest a year and a half ago. She soon realized that there was little, and sometimes no, historical data on water characteristics she most wanted to investigate - temperature, conductivity (the ability of water to dissolve and transport salt and other solids), nutrient levels, and primary productivity (the ability to support life at the bottom of the food chain, e.g., algae).

McKnight does have access to some lake temperature data from the summers of 1982 and 1983, and some water chemistry data for point locations throughout the lake for summers when Yukon Environment has conducted fish surveys at Kluane, she says. “But it’s tricky when you have data from 1983 and 2015 with very little data between these years. You can’t determine a trend with two points in time.”

In order to answer the most pressing questions about any changing water conditions, McKnight realized she would have to “take a step backwards” and initiate a comprehensive baseline study.

“‘Baseline study’ may not sound very significant at first,” she says, “but monitoring lake changes over time and over space is not possible without baseline data.” And, she says, such a study can be very interesting in and of itself.

Why then is there a shortage of such data on Kluane Lake and on the big lakes of the Far North in general?

It’s not that scientists in the Kluane area haven’t been hard at work, and not that local residents haven’t been generous with their knowledge and skills, McKnight stresses. Researchers around Kluane have been diligently studying the effects of changing climate on permafrost, glaciers, communities, vegetation, wildlife… and the list goes ever on.

But the big lakes, despite being sources of food and potable water, and despite their effects on local climates and their essential role in maintaining biodiversity, have been neglected. Logistical issues are a major reason for that, says McKnight. Most northern lakes are isolated in rugged country and costly to reach.

The local conditions are often harsh. Arctic cold, wind and snow dominate the surroundings for much of the year. Meanwhile, lakes must be visited frequently to establish detailed, effective water-parameter baselines over time.

Large water bodies can be very sensitive to change - slight changes in various water characteristics could have large impacts on both the aquatic and neighbouring terrestrial environment.

McKnight departed Edmonton for Kluane Lake in February. She was based at the Kluane Lake Research Station and at the communities of Burwash and Destruction Bay, depending on study-site locations.

“Typically, we’d load up the snow machine and a sled. We’d carry an ice auger and safety and science equipment,” she says. That equipment included sondes - probes designed to test for such characteristics as oxygen, conductivity and temperature at different water levels.

The researchers targeted 20 sites on the lake. When they reached prearranged GPS co-ordinates, they’d auger a hole and lower their probes almost to the bottom of the lake.

“We’d pull them up slowly - recording data throughout the water column,” McKnight says. “We’d measure ice thickness and collect water samples.”

During the months when the water was ice free, the work would be much the same, but undertaken from a boat.

Ice-pressure ridges are dangerous obstacles for snow-machine travel, she says. And in warmer months, katabatic (downsloping) winds coming off the St-Elias ice fields can create nearly oceanic waves. Researchers must live beside the lake during all four seasons to be on hand when conditions allow for safe travel on the water and ice.

McKnight makes good use of her shore-bound time by getting to know the locals and listening to their advice and stories. And Kluane Lake is certainly a repository of fascinating stories. In one famous instance, in the 1700s the Kaskawulsh glacier advanced and blocked the southern outflow of the lake. Currents reversed. Water rose. Yukon River chum salmon began to make their way into the lake via the Kluane River - as they still do.

“Kluane is like three lakes in one,” says McKnight, referring to its Y- shape - its two northern arms and one southern arm. Temperatures in the arms can vary greatly. In mid-summer last year, it was eight degrees at lake surface on the south end and 16 degrees at lake surface in the north end, she says.

Exchanging information with people in the communities is an enjoyable priority, she stresses. And locals, experts on water and ice travel, operate the boat and snow machines and help McKnight with her research chores. “Community members are tons of help,” she says.

Hopefully, the baseline will identify key monitoring sites which can be revisited regularly over coming years. Perhaps monitoring can be done by community members themselves, she adds.

Meanwhile, other academic researchers are looking into mercury levels in Kluane Lake and exchanging anecdotes and data with McKnight. See Your Yukon for Nov. 6: Mercury and the North’s lake-bottom line.

The comprehensive baseline data from Kluane Lake may someday be compared with the discoveries made by scientists working on other, far-distant northern lakes, she says. For instance, a university team is probing Ellesmere Island’s Lake Hazen, the largest lake entirely north of the Arctic Circle. Historically, Hazen was often covered by ice year-round, but is now opening during summer

There are plenty of complex lake systems like Kluane and Hazen to keep graduate students busy for the foreseeable future.

“When it comes to lakes and climate change, there are a million questions,” says McKnight.

This column is co-ordinated by the Yukon Research Centre at Yukon College with major financial support from Environment Yukon and Yukon College. The articles are archived at