How might ocean acidification already be affecting oceans near places you live, travel or care about? Read on to learn about the dangers they — and the species they harbor — are already facing.
For nearly all of the past six years, baby oysters could not grow in Willapa Bay, partly because of acidification. This area provides one-sixth of the nation’s natural oysters, and oyster farms in Washington and Oregon have reported hatchery failures in recent years. The Pacific Northwest is a warning of what’s to come if we don’t curb our emissions. Tide pools up north are also changing, with mussels and other shell-building animals being replaced by grasses and unshelled organisms.
A research cruise along the Pacific Coast found that acidified waters were coming closest to shore in Northern California. Indeed, waters affected by ocean acidification are welling up from the deep during certain seasons and exposing marine life to corrosive waters. These waters were last exposed to the atmosphere about 50 years ago, when CO2 levels were much lower than they are today. This means there’s even more trouble in the pipeline. Monitoring has documented increased levels of CO2 in the waters of Monterey Bay and corresponding acidification.
Alaska’s polar waters are especially vulnerable to ocean acidification. Cold waters easily absorb CO2 and they’re also naturally less conducive to shell-building. A notable change in water conditions has occurred since 1997 making the waters unfavorable for shell-building, partly from ice melt and organic processes. But it is getting worse. In the most extensive study of Alaska’s waters, researchers found seasonal corrosive waters in the Bering Sea. They determined that these waters crossed the tipping point because of ocean acidification. Effects on Alaska’s ecosystems and fisheries are already underway.
Coral reefs in Florida are in crisis. Already global warming, fishing, disease and pollution have devastated these once-magnificent reefs, Florida’s dominant reef-building corals have declined upwards of 70 percent in just 30 years. The waters of the greater Caribbean are now beginning to feel the impacts of ocean acidification, and if atmospheric CO2 levels reach 450 parts per million (today, it’s about 391 ppm), the waters will become noticeably worse for reef building. Ocean acidification will decrease the ability of Florida’s imperiled elkhorn coral to reproduce, which in this century will halve the number of baby corals settling on the reef, and those that survive will have difficulty growing into reefs.
With its vast coral reefs and rich ocean diversity, Hawaii faces enormous risk. Hawaii has one of the few monitoring stations of ocean acidification, and it has documented a 20-year change in seawater acidity that parallels CO2 levels in the atmosphere. Hawaii is home to a diversity of corals that so far have escaped the devastation of mass bleaching events. Yet ocean acidification looms, and it alone is predicted to cut Hawaii’s coral cover by one-third within this century. Hawaii's coral reefs are worth $33.57 billion a year, and keeping ocean acidification in check will be vital to supporting healthy coral reefs, reef-dependent marine life, and the services these provide to coastal communities.
The eastern seaboard’s coastal estuaries are among the most biologically productive environments and are a vital support system for water purification, wildlife nursery grounds, shellfish and other fisheries, flood and storm-surge protection, and human recreation. Acidification is affecting the Chesapeake Bay even faster than the open ocean. Already, shell-building of juvenile oysters has been compromised, and oyster populations are plummeting to historically low levels. While atmospheric CO2 is not the only source of Chesapeake Bay’s acidity, its contribution cannot be ignored. A study of clams, scallops and oysters showed that levels of CO2 expected this century will significantly decrease the size, growth and survival of the Atlantic’s commercially and ecologically valuable shellfish.