What is ocean acidification?
The ocean naturally absorbs over a quarter of the carbon dioxide (CO2) in the atmosphere. So as a result of rising atmospheric CO2 concentrations from burning fossil fuels, levels of CO2 in the ocean are also increasing. When CO2 enters the ocean it reacts with sea water and forms carbonic acid (H2Co3). Carbonic acid is a weak acid which separates or dissociates into a hydrogen ion (H+) and a bicarbonate ion (HCO3-). As more hydrogen ions are formed from this reaction, the pH of the ocean is decreasing, meaning it is becoming more acidic. This is called ocean acidification (OA).
Over the last 200 years, the ocean has become 30% more acidic. The last time it was this acidic was over 300 million years ago. This is presenting new challenges for marine life, and especially for organisms with hard shells and skeletons like oysters, mussels, crabs, and corals.
Learn more about OA and how it impacts marine life in national parks.
Like sea temperature rise, OA is a huge threat to marine life. But for now, it is harder to track remotely on a large scale. So this summer, seven West Coast national parks are teaming up with the 2021 National Oceanic And Atmospheric Administration (NOAA) West Coast Ocean Acidification (WCOA) Cruise. They’ll collect water samples in-person to check several OA indicators. Their data will help paint the most detailed picture yet of OA conditions up and down the coast, from parks’ rocky intertidal zones to dozens of miles offshore.
The National Park Service (NPS) and NOAA tested a similar collaboration for the first time during NOAA’s 2016 WCOA Cruise. As scientists aboard the NOAA ship collected water samples offshore of Cabrillo National Monument and Olympic National Park, scientists at the parks collected samples from their intertidal zones. This time, scientists at Cabrillo National Monument, Channel Islands National Park, Olympic National Park, Point Reyes National Seashore, Golden Gate National Recreation Area, Redwood National Park, and Lewis and Clark National Historical Park will participate.
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The 2021 WCOA cruise will head from north to south. Along the way, it will pause to travel along over a dozen established transects perpendicular to the coast. That will allow the scientists on board NOAA’s Ronald H. Brown research vessel to collect water samples at different depths and distances from shore. Olympic will be the first park site it reaches in late June. When it gets there, the scientists at Olympic will have their sampling gear ready to go. Coordinating the timing of the sampling means the samples can be used to help decipher the spatial patterns of OA from the very edge of the shore, out to the sea.
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National Park Service, 9 July 2021. Article.
