The general acidity of the oceans has risen 30% since the Industrial Revolution. The culprit is carbon, which is being released into the atmosphere through the burning of fossil fuels such as coal and oil. The oceans act like massive sponges soaking up airborne carbon. As carbon dissolves in seawater it forms carbonic acid, which lowers pH and increases acidity.
The Pacific Coast of North America is being hit particularly hard because, due to a unique system of wind and currents, deep water surfaces along the west coast. This older water has been absorbing carbon for a relatively long period of time and is therefore unusually acidic. Ocean water off the Pacific coast has absorbed so much carbon that it is becoming acidic enough to melt the shells of sea creatures.
The West Coast shellfish industry, which contributes more than 100 million dollars a year to the economy and provides thousands of jobs, is in jeopardy. Acidity levels are already high enough to prevent oyster larvae from forming shells. Some hatchery businesses have moved to Hawaii. Others are installing expensive monitoring equipment and shutting down operations when acidity is too high.
The harm done to oyster farmers is just the tip of the iceberg. Acidification could disrupt the entire marine food web. Pteropods are tiny, snail-like creatures that are a fundamental food source for myriad species, from fish to whales. They make up 50 percent of the diet of Northwest salmon. Researchers predicted pteropods could begin dissolving by mid-century, but Seattle scientists have recently discovered that acidifying seas are damaging pteropods right now — decades earlier than expected.
Coral reefs are also in the crosshairs of ocean acidification. Acidity slows reef-building and eventually leads to their erosion and extinction. Coral reefs serve as the home for many species and their disappearance would have profound consequences on the food web.
Researchers predict that if carbon emissions continue at their current rate, ocean acidity will more than double by 2100. The oceans provide over 25 percent of all protein consumed by the entire human species. The collapse of the marine food web and the numerous fisheries that depend upon it will have incalculable ramifications for a human population headed toward ten billion people.
As the first place in the world to experience real-time ecosystem and economic disruption from ocean acidification the West Coast has become a dynamic laboratory for a carbon-imbalanced world. We are the canary in the global coal mine. Much is riding on our response.
For more information see the report from Washington State’s Blue Ribbon Panel on Ocean Acidification: http://www.ecy.wa.gov/water/marine/oceanacidification.html