Biologists find new environmental threat in North American lakes

Kingston, ON

Calling the phenomenon “aquatic osteoporosis,” Queen’s PhD candidate Adam Jeziorski, lead author of the study, notes that calcium is an essential nutrient for many lake-dwelling organisms. “Once calcium declines below a certain threshold, some keystone species can no longer reproduce,” he says. “These species and other organisms that feed on them are endangered.”

…The researchers found that key invertebrate species were disappearing in the lakes with declining calcium levels, often starting in the 1970s.

Linking the problem to the long-term effects of acid rain on forest soils, as well as to logging and forest re-growth, the researchers note that, despite signs of chemical recovery from recent reductions in sulphur dioxide emissions, lower calcium levels may delay the biological recovery of lakes from acidification.

“This is all very worrisome,” concludes Dr. Smol, recipient of the 2004 NSERC Herzberg Gold Medal as Canada’s top scientist and co-director of Queen’s Paleoecological Environmental Assessment and Research Laboratory (PEARL). “The good news is that we have found the ‘miner’s canary’ in the form of these water fleas that track the decline in calcium levels. The bad news is that many lakes have already passed these critical thresholds.”

EurekAlert