New research from Queen’s University has shown that mercury biomagnification rates in aquatic ecosystems in the Arctic are higher than those in warmer climates.
Biomagnification is the process in all ecosystems which leads to increased concentration of substances like mercury in organisms at increasingly higher levels of the food chain (see chart below). However, this new study by researcher Raphael Lavoie demonstrates that colder temperatures increases the rate of biomagnification in Arctic food chains.
“High Arctic ecosystems are already affected by global changes. When contaminants from human activity end up in the Arctic, they tend to stay there,” said Mr. Lavoie in a release. “Mercury will always biomagnify, but we’ve found that depending on the latitude, the degree of biomagnification will vary.”
The low Arctic temperatures slows the metabolism and growth rate for Arctic aquatic life compared to warmer climates.
As the growth rate of marine life in this climate is reduced, their bodies contain higher concentrations of mercury compared to organisms in warmer temparatures, where growth rate is accelerated.
“Our study indicates that fragile arctic ecosystems may be more at risk from mercury pollution than ecosystems in other parts of the world,” says Mr. Lavoie. “In addition, arctic food webs may be slower to respond to current efforts to reduce mercury pollution. Our study highlights the need for consistent data collection and collaboration to monitor mercury in food webs across the globe.”
Mercury is naturally produced by volcanoes and forest fires, however mercury production has increased significantly world wide due to human activities that include coal burning and artisanal gold extraction, where toxic materials are used in the recovery process.
7000 tissue samples in 205 aquatic food webs from 31 countries and oceans provided data used by the researchers. In addition, data from 69 other studies were collected and incorporated by Lavoie and his team to produce the first comprehensive study of mercury biomagnification trends.
Led by Raphael Lavoie, the team was supervised by Dr. Linda Campbell of St. Mary’s University and co-authors of the paper included Dr. Timothy D. Jardine (University of Saskatchewan), Dr. Matthew M. Chumchal (Texas Christian University) and Dr. Karen A. Kidd (University of New Brunswick).
For more information, read this synopsis at St Mary’s University or in the online edition of Environmental Science and Technology.
—————————————————————————————
Top photo (Arctic grayling): Wikimedia Commons | Chart source: St Mary’s University / Designed by David Orr
