The marine waters of the Pacific Northwest are particularly vulnerable to ocean acidification. Regional marine processes including coastal upwelling exacerbate the acidifying effects of global carbon dioxide emissions. Coastal upwelling brings deep ocean water, which is rich in carbon dioxide and low in pH, up into the coastal zone. This upwelled water has spent decades circulating deep in the ocean, out of contact with the atmosphere for 30 to 50 years. This means that the waters currently upwelled onto the coast of the Pacific Northwest reflect the atmospheric carbon dioxide concentrations of the 1970s and 1980s. We will continue to see more acidifying conditions coming from upwelled waters into the future.

Other local factors that include runoff of nutrients from land, and local emissions of carbon dioxide, nitrogen oxides, and sulfur oxides, which are absorbed by seawater from the atmosphere, also impact the chemistry of the waters of the Pacific Northwest. The relative importance of these local factors varies by location. For example, acidification along the outer coast of Washington and Puget Sound is strongly influenced by coastal upwelling while acidification in shallow estuaries, including those in Puget Sound, may be influenced more by run off from fresh water sources (which are naturally low in pH) that are carrying nutrients from human and natural sources.

Shellfish along the West Coast is an $111 million industry, supplying 1000s of jobs in Oregon and Washington. Less than a decade ago, shellfish hatcheries in Oregon and Washington, essential to shellfish growers all along the West Coast, were on the verge of collapse. In 2012, scientists in Oregon found evidence that higher levels of carbon dioxide in the Pacific Ocean were responsible for the failure of oyster larvae to survive in 2005 at Whiskey Creek Shellfish Hatchery on Netarts Bay (Barton et al, 2012). Federal and state investments in monitoring of coastal seawater have helped to provide shellfish hatchery managers with real-time data on the seawater coming into their hatcheries. The data provide an early warning system, signaling the approach of cold, acidified seawater one to two days before it arrives in the sensitive coastal waters where shellfish larvae are cultivated. The data help hatchery managers schedule production when water quality is good, anticipate the need to buffer or adjust the chemistry of the water coming into their hatcheries, and avoid wasting valuable energy and other resources it water quality is poor.