Scientists embark on West Coast ocean acidification mission

SEATTLE — On Monday scientists from the National Oceanic and Atmospheric Administration will begin a one-month U.S. West Coast expedition to investigate ocean acidification, an issue that poses a serious threat to the Pacific Northwest’s shellfish industry.

“We will for the first time not only study the chemistry of acidification, but also study the biological impacts on the marine ecosystems in the open ocean,” says Richard A. Feely, a scientist from NOAA’s Pacific Marine Environmental Research Laboratory in Seattle. Feely is co-chief of the mission.

Over the past 30 years, oceanographers like Feely have found that the burning of fossil fuels has released about 2 trillion tons of carbon dioxide into the atmosphere. About a quarter of that has been absorbed by the oceans, Feely says. Carbon dioxide reacts with seawater to form carbonic acid and that acid can corrode the shells of calcifying organisms including oysters and clams.

This upcoming expedition follows the same path taken during a similar survey in 2007, stretching from the Canadian border to the Mexican border. That earlier expedition was the first survey to show that the West Coast of North America is a hot spot for ocean acidification.

Feely explained that the tendency for the West Coast to have some of the world’s most corrosive waters comes in large part from a natural upwelling process that pulls corrosive waters from deep in the ocean to West Coast shores, where shellfish live.

Because the West Coast has these higher levels of acidity, Feely explained, taking a closer look at these waters is a chance to get a snapshot of what the future could look like for oceans across the globe.

“The results (of the 2007 mission) were a huge wake-up call for West Coast seafood producers, especially for shellfish producers,” says Brad Warren, director of the Global Ocean Health Partnership, a joint sustainable fisheries partnership and National Fisheries Conservation Center program. “The seafood industry has a lot, potentially everything, at stake.”

Shellfish are particularly susceptible to changes in pH during the larval stage when acidifying waters can prevent them from forming shells. This has lead to massive waves of mortality at oyster hatcheries throughout the Pacific Northwest in recent years.

“What folks at NOAA have done is begin to make it possible for people to see what’s happening. It’s like turning on the lights in a room where you’re being hit by people and you can’t see the fists coming,” Warren said.

Warren says the information gathered on this mission will help Pacific Northwest shellfish growers develop ways to adapt to the changing pH of the oceans.

Mission scientists on board the NOAA ship Fairweather will also look at the impacts of acidification on a tiny organism called a pteropod, or a “sea butterfly.” This creature is about the size of a pea and is eaten by organisms as small as krill to as large as whales. Pteropods are also a major food source for North Pacific juvenile salmon.

Other mission scientists will look closely at the impacts of decreased pH on toxic algal species, which could lead to an increase in the prevalence and toxicity of harmful algal blooms. Algal blooms can cause various forms of shellfish poisoning which can be harmful to people and animals that eat those poisoned shellfish, including marine species like sea lions, sea otters and sea birds.

In addition to these expeditions, NOAA scientists have been been conducting ongoing monitoring of the increase in levels of carbon dioxide through testing equipment stationed on moorings throughout the West Coast.

“Right now we’re seeing a pH change that’s on average about .002 pH units per year consistently along the coast,” Feely said.

With pH, tiny changes can have huge impacts. Since the beginning of the Industrial Revolution, the pH of surface all ocean waters has fallen by 0.1 pH units. This change represents about a 30 percent increase in acidity.

NOAA oceanographers predict that oceans will continue to absorb carbon dioxide and by the end of this century the surface waters of the ocean could be nearly 150 percent more acidic. This would cause the pH of the oceans to drop to a level that hasn’t been experienced in more than 20 million years.

Photos and updates from the ocean acidification mission will be posted online throughout the journey at NOAA’s Ocean Acidification program website.

EarthFix, 25 July 2013. Article.

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