The following article originally appeared in the Kenora Miner
& News. It is reproduced here with the permission of
the Kenora Miner & News.
Kenora Miner & News
Elsie Neufeld
March 13 2002
Scientists extract samples to reveal history of lake
By Elsie Neufeld
Miner and News Staff
Lake of the Woods gave up a few volumes of her history last
week when a Department of Fisheries and Oceans team extracted
sediment cores from her bottom.
From Monday to Friday, the team put in long days working
with ice and water, collecting the samples which will tell the
history of the lake's water activity, what has lived in it,
fell into it and washed into it over the past 100 to 200
years.
When the expedition was being planned in February, warm
temperatures promised spring. By the time the team was on
location, winter was back. Old Man Winter blew one last frigid
breath across the lake - temperatures ranged from -12C to
-18C.
"It was much colder than we expected," said Bob
Danell, head of the sampling team, a field technician in the
radiochemistry lab at the Department of Fisheries and Oceans
in Winnipeg. Cold is no deterrent, though.
"We're used to it," Danell said. His team usually
works in the high Arctic. They dress properly and have a tent
where they can escape the wind. Inside is a camp stove
providing heat and hot water to keep people and equipment
warm.
Last Wednesday, the drill site was at Deception Bay. The
hole in the ice had been drilled and the coring tube was being
winched down. Two technicians watched a sonar screen trying to
determine the depth of the bottom.
The core tube, about 10 cm in diameter and 80 cm long, was
being lowered slowly to touch the lake bottom.
When it reached the bottom, the tension was taken off the
line enough to let it sink into the sediment, but not enough
to tilt. Sometimes the core sinks too far and the sediment
flows over the top.
If that happens the sample must be retaken with a longer
tube.
"They must catch the interface (where water meets the
bottom of the lake) in the tube," said Mike Stainton.
Stainton is with the Analytical Unit, Environmental Science
Division of the Freshwater Institute at the Department of
Fisheries and Oceans in Winnipeg. He has been working with the
Lake of the Woods District Property Owners Association to get
this project done.
The Lake of the Woods District Property Owners Association
contributed $20,000 to have two core samples tested. The
association is concerned about the water quality of the lake.
In particular, the association worries that algae blooms on
the lake are indicating nutrient overloading in the lake.
The sediment samples will reveal the history of algae
activity. A history would show what it was like before
development started on the lake and what has happened with
development.
However, before those samples mean anything, they must be
dated. Everything depends on that.
"We are the most important ones," Danell said.
"Without us doing it properly and dating it properly
(the other tests are pointless)."
Each core will take up to two or three months to date, he
said.
The core drawn up from the bottom of Deception Bay is about
65 cm long. It is carried into the tent and set on a pedestal.
There it is sliced, half a centimetre at a time, and put into
labelled sample bags. Sub-samples are taken off for diatom
analysis and the balance are freeze-dried for dating and other
analysis later.
Some of these samples will have to wait until funds and/or
opportunity are available.
While the team aimed to collect samples from eight sites,
it managed only seven. Time ran out for them. The sample sites
were: Poplar Hill Bay, White Partridge Bay, Clearwater Bay
(Deception Bay), Gardner Island, Cochrane Island, White Fish
Bay and near Sioux Narrows. A site near Northwest Angle had to
be skipped. The team hope to do it at a later date.
It will be a long while before any of the results are known
but the writing of the hidden history has begun.
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