Each year the world's oceans absorb huge amounts of atmospheric carbon dioxide from automobile, power plant emissions and other sources. Widely known for its role in climate change, carbon dioxide also increases the oceans' acidity, with potential for profound effects on marine ecosystems.
Rippling Through the Food Web
While species like clams or corals are particularly vulnerable because too much acidity can literally dissolve their calcium carbonate shell, the consequences of acidification can ripple through the entire food web, affecting everything from microscopic plankton, to salmon, to orcas.
Scientists expect current ocean patterns to cause some of the greatest increases in ocean acidification off our shores in the Pacific Northwest, and the Northwest Fisheries Science Center is actively researching the potential impact.
Initial Tests: Vulnerable and Valuable
The Center is laboratory-testing the response of economically and ecologically important species in waters off the Oregon and Washington. Initial studies will examine:
- geoduck clams
- Dungeness crabs
- echinoderms (sea stars and sea urchins)
Because carbon dioxide has effects upon both ocean acidity and climate change, we are exploring how the combined effects of acidification and warming affect West Coast marine species.
While laboratory experiments tell us how individual species are directly affected by acidification, we must also determine how changes to susceptible species will affect the entire food web. For example:
- Will acidification caused changes in zooplankton composition affect food available for salmon, which in turn serve as food for orca?
- Will changes in eel grass growth (which actually increases in a carbon dioxide rich environment) alter the abundance of eel grass dependent species?
- Will non-commercial species like jelly fish that do not seem susceptible to acidification increase in abundance at the expense of harvestable fish?
To address these question, we are developing models to help predict how acidification induced changes will ripple throughout the entire marine system.
Given the current load of carbon dioxide in the atmosphere, some acidification has already taken place and more is inevitable as the oceans continue to absorb the gas. However, lower carbon dioxide emissions can reduce future acidification, and avoid some consequences of this fundamental change in ocean chemistry.
As acidification alters ocean ecosystems, scientists at the Northwest Fisheries Science Center are at the forefront of research that will help us anticipate what those changes will be.
Several NWFSC divisions conduct research on ocean acidification. You can learn more about each division by clicking on their names.