Whenever scientist Iria Giménez wants to contemplate her work, she settles on a wobbly driftwood bench perched on a mossy rock bluff and stares over the waters of Hyacinthe Bay on Quadra Island.
But despite the remoteness of her thinking spot on the small ferry-dependent island, Giménez is just steps away from the Hakai Institute’s cutting-edge Marna Lab, a key research hub on the biological impacts of ocean acidification (OA) and climate change on the B.C. coast.
A postdoctoral research fellow with Hakai and the University of British Columbia, Giménez heads a team of female scientists at the lab investigating the effects of ocean acidification and other climate change impacts on shellfish and various marine organisms.
Ocean acidification and hypoxia (OAH) — dangerously low oxygen levels in the marine environment — have been identified by the province as one of the top climate risks for the B.C. coast.
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Shellfish especially vulnerable to increasing ocean acidification
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The acidity of the ocean is rising as it absorbs increasing amounts of carbon dioxide from human-caused emissions.
This process reduces the amount of calcium carbonate available in oceans necessary to build the shells or skeletons of many sea creatures — including crabs, shellfish, prawns, sea urchins and other tiny organisms that are important in the marine food web.
Baby oysters are particularly vulnerable when they are in the larval stage because they have a very limited window of time and energy to create their initial shell and be able to begin feeding themselves, Giménez said.
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If the conditions aren’t ideal, the tiny larval oysters can die or construct inferior shells that make them more vulnerable to other stressors or diseases down the road, she said.
Ocean acidification doesn’t impact shellfish in isolation, she added. Other factors such as warming waters, an increase in pathogens, less food availability, salinity and oxygen levels may all be intertwined and behind the large summer die-off events shellfish farmers in B.C. have been experiencing in recent years.
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Marna Lab boasts advantages in the study of ocean acidification
Ongoing research at the Marna Lab will advance the understanding of acidification by simulating a range of conditions and teasing out individual factors and thresholds in a controlled manner, said Giménez.
The Quadra-based lab has a number of advantages, she said.
It’s equipped with 40 high-tech mesocosms — large aquariums that allow researchers to accurately control water properties such as pH, temperature, salinity and carbonate saturation levels to mimic current or projected ocean conditions and climate stressors.
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The lab also uses bioreactors, which look remarkably similar to space capsules, to grow algae to feed shellfish in their tanks.
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Do stressed-out shellfish pass survival tactics to offspring?
The lab has run a variety of experiments over the past year and half, and is in the process of analyzing all the results, Giménez said.
One of the puzzles the research team has been working on is if adult shellfish stressed by acidification provide any advantages or disadvantages to their offspring in surviving similar conditions.
One interesting response by shellfish “parents” is they tend to spawn faster and earlier when placed into more corrosive waters with higher carbon dioxide levels than those that aren’t, Giménez said.
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Rochelle Bakes, Canada’s National Observer, 4 March 2022. Full article.
