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Delineation of Ocean Acidification and Calcium Carbonate Saturation State of the Atlantic Zone



Atlantic Zone biogeochemical monitoring stations (circles) with sites proposed for the acidification survey in purple. Credit: DFO

Ocean acidification, caused by the formation of carbonic acid as atmospheric carbon dioxide (CO2) dissolves in the ocean, is expected to have profound effects on marine ecosystems. Organisms that form shells and skeletons of calcium carbonate (CaCO3), including phytoplankton, zooplankton and other invertebrates, will be particularly affected. As ocean acidity increases, there is a decline in the degree to which sea water is saturated with CaCO3 (called the “saturation state”), making it more difficult for organisms to form their protective outer shells. The Northwest Atlantic contains the largest inventory of CO2 from human activities in the world.

In the autumn of 2014, this project sampled a range of variables related to ocean acidification—including dissolved inorganic carbon (DIC), total alkalinity (TA), and pH (a measure of acidity)—at 102 sites in the Atlantic Zone in order to establish baseline measurements of ocean acidification status. DIC and TA will be used to estimate the saturation state of CaCO3 at each site. Results from these analyses will be used to develop regional maps of bottom water saturation states, which will enable evaluation of the potential risk of damage to crabs, shrimp and other shellfish. The maps will inform state of the ocean assessments and decision-making related to the fisheries management, existing and future marine protected areas, NAFO Footnote 1 assessments of vulnerable marine ecosystems, and other ecosystem-related decisions.

Program Name

Aquatic Climate Change Adaptation Services Program (ACCASP)


2014 - 2015


Atlantic: Newfoundland, Labrador Shelves

Principal Investigator(s)

Pierre Pepin
Chair, Atlantic Zone Monitoring Program, Newfoundland and Labrador
Tel.: (709) 772-2081

Stephen Snow
Division Manager, Oceans, Newfoundland and Labrador
Tel.: (709) 772-2852

Kevin Anderson
Director, Fisheries Management, Newfoundland and Labrador
Tel.: (709) 772-4543

Team Member(s)

Kumiko Azetsu-Scott, DFO, Maritimes Region

Blair Greenan, DFO, Maritimes Region

Stephen Punshon, DFO, Maritimes Region

Catherine Johnson, DFO, Maritimes Region

Michel Starr, DFO, Quebec Region

Peter Galbraith, DFO, Quebec Region

Diane Lavoie, DFO, Quebec Region

Joël Chassé, DFO, Gulf Region

Gary Maillet, DFO, Newfoundland and Labrador Region

Collaborative Partner(s)

Atlantic Zone Monitoring Program

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