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Effects of Ocean Acidification on Marine Fauna and Ecosystem Processes in the Northwest Atlantic


Cod, pre-hatching (light field). Atlantic Cod eggs after exposure to reduced pH-levels in the lab. Photo: Steven Neil, DFO

To date, global studies have revealed that marine organisms have a diverse response to climate-change related ocean acidification, an increase in ocean acidity or declining pH (a measure of acidity) as atmospheric carbon dioxide (CO2) dissolves in surface waters, forming carbonic acid. The most direct biological impact will be on organisms that form shells and skeletons from calcium carbonate (CaCO3) in seawater. Since higher acidity increases the solubility of CaCO3, shellfish, corals and some phytoplankton and zooplankton will find it more difficult to form and maintain their shells and skeletons.

Variation in species' ability to accommodate and adapt to changes in ocean biogeochemistry require that studies be carried out on local and regional scales. This project will examine the biological impacts of the projected increase in ocean acidification on marine fauna in the Northwest Atlantic. Dr. Trippel will continue to examine the impacts on Atlantic Cod and American Lobster, and he will also initiate studies on Green Sea Urchin, Sea Scallop, Soft-Shell Clam and Blue Mussel, which are commercially important and widely distributed in the coastal zone. Dr. Starr will continue research into the impacts on key ecosystem processes using mesocosms—experimental water enclosures—with sea water from the St. Lawrence Estuary containing a natural community of phytoplankton. He will also study the effects of different pH levels and long-term exposure to lowered pH on Northern Shrimp and the copepod Calanus hyperboreus. The sensitivities of species to ocean acidification and their geographical distributions will be made available to other ACCASP activities as needed.

Program Name

Aquatic Climate Change Adaptation Services Program (ACCASP)


Atlantic: Gulf of St. Lawrence, St. Lawrence Estuary

Principal Investigator(s)

Edward Trippel
Fisheries and Oceans Canada

Michel Starr
Fisheries and Oceans Canada

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