New face of the Canadian Shield

“This forest should never be cut,” said Norman Yan, a York University biology professor, regarding the lands surrounding the Dorset Lakes near Sudbury.

Yan presented his findings on the decrease of calcium in Canadian Shield lakes at Wilfrid Laurier University on Jan. 21.

According to Yan, his research was initiated after realizing the decline in calcium and the lack of understanding on its implication for marine wildlife.

“No one knew anything about [how] levels of calcium that might actually be damaging,” explained Yan.

He specifically analyzed the implications on zooplankton, including the jelly-like holopedium, daphniids and the spiny water flea bythotrephes.

After looking at several lakes across Ontario and comparing the results to other areas across the Canadian Shield, a pattern emerged.

“When we see such coherence in our lakes we should look at changes in the environment,” said Yan.

Calcium levels in the lakes have decreased due to sulphur dioxide (SO2) emissions from pollution, acid rain and logging.

Although the acidity of rain has improved by approximately 50 per cent from the early 1980s to the early 2000s, the other detrimental elements remain an issue.

“We should see more daphnia in lakes than 30 years ago,” said Yan. However, numbers of daphnia have been on the decline, while holopedium and bythrotrephe populations have risen.

Although Yan’s study was very specific to the wildlife affected by these changes, the impact of calcium depletion has not been studied for any other species.

All living creatures need a certain amount of calcium to survive.

Calcium in the forest soils is not only important to life in the lakes, but also to the re-growth of trees and shrubbery.

“We don’t understand the magnitude of the threat and where humans are involved so if we can understand that magnitude maybe something can be done,” said Yan.

As the issue does not appear to be improving, resolving the declination of calcium is equally as important to understanding its implications.

“We have to add calcium back to the soil,” said Yan. “I do like the idea of developing a wood-ash recycling program so that every logging truck or skinner would have a 25 gallon drum of wood-ash in the back.”

“For every ton of trees they took out they’d have to sprinkle a certain number of pounds of wood-ash back in the land and a dramatic reduction of SO2 emissions.”

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