Discussions of ocean acidification start at UVic

Oceanographers and experts gathered at the Victoria Conference Centre last month for a two day expert’s forum on ocean acidification. Running from Feb. 18–19, participants met with the intention of establishing a Canadian effort to address the impacts of ocean acidification. Kicking off the event the night before, Ken Denman of the UVic School of Earth and Ocean Sciences gave a talk on the subject in the David Turpin Building.

“There’s reason to be concerned, but part of that concern is that we don’t really know how things are going to play out,” said Denman in an interview with the Martlet. “The ocean acidification issue has kind of crept up on us, I think. Where the climate change issue is nebulous in some ways, especially for people who live on the coast or make their living by raising shellfish, this is much more immediate.”

Ocean acidification is a result of fossil fuel emissions. As Denman explains it, one third of carbon dioxide in the atmosphere is absorbed by the ocean. As the CO2 dissociates and combines with water, hydrogen ions are released from the ocean, lowering the pH level and therefore making the water more acidic.

Referring to pteropods as the poster child of ocean acidification, Debby Ianson of the Department of Fisheries and Oceans explains how certain changes are already being noted. “[Pteropods] have shells that are made of calcium carbonate. The mineral structure that they use is the type that is most susceptible to changes in acidity. At a higher pH it dissolves.”

Ianson describes pteropods as tiny snail-like sea butterflies that are just visible to the naked eye. Pteropods harvested from areas of lower pH levels have been found with pitted and unhealthy shells. “[What] we don’t know is what they looked like 10 or 20 years ago,” said Ianson. “But, we can look at their condition and look at the chemistry of the water and make that link now.”

Denman pointed out that many factors of this issue are still unknown. As oysters and other shellfish are particularly susceptible to minute environmental changes, it is not simply the lowered pH that is affecting them but also rising temperatures and a decrease in the amount of dissolved oxygen. “It’s not just one stress on these animals,” said Denman. “It is at least three.”

“The number one thing that everyone can do is consider their own carbon footprint,” said Ianson. Though in a worst-case scenario multiple species could die off and affect the remaining ecosystem, Ianson pointed out that the ocean is still basic. On a pH scale, coffee and fresh water are still more acidic than ocean water.

To learn more about the event, visit meopar.ca/news-events/meoparoa.

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