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Ocean of Change: Changing chemistry of seawater poses lethal threat to marine life

Published:  Sept. 22

 

Oregon fishermen tell stories of strange events on the Pacific Ocean that have made them shudder over the past half dozen years.

The Whiskey Creek Shellfish Hatchery on the state’s north coast watched oyster larvae die en masse for three years in a row in the mid-2000s — depriving oyster farms along the entire West Coast of seed oysters.

Florence crabber Al Pazar saw baby octopuses, an inch or two long, climb up his crab lines to escape the sea waters in the 2005 season. When he pulled up his pots, the crab were dead.

Eugene fisherman Ryan Rogers, who drags in great piles of salmon on an Alaska purse seiner, has instead brought up nets full of jellyfish in recent years.

“Sometimes we’ll catch 4,000 or 5,000 pounds of jellyfish. They spray all around. We get stung,” he said. “It makes it difficult to bring your net in. You have to let it go and lose the salmon that are in your net.”

Scientists — including many at Oregon State University — are beginning to define the cause of these events. They call it ocean acidification and hypoxia.

Wind, currents and ocean chemistry conspire to create pools of corrosive waters that can be lethal to key commercial species in Northwest waters — and favorable to some nuisance species, such as jellyfish.

The die-off of coral reefs has been publicized everywhere from Australia to the Indian Ocean to the Caribbean. But less well known are the problems surfacing on the West Coast of North America — where people may have more cause to worry.

“Scientists are learning that ocean acidification is hitting waters off the West Coast earlier and harder than elsewhere on the planet,” Oregon Gov. John Kitzhaber said recently.

Kitzhaber in August appointed five Oregon State University scientists to a multistate panel that’s charged with determining the extent, causes and effects of ocean acidification along the Pacific coast.

Acidification is a potential threat to shellfish and other marine life and also to thousands of jobs that depend on them, according to the governor, so the state needs a clearer understanding of what’s happening in Oregon’s waters.

Oyster growers, crabbers and fishermen have reported losses in the millions related to the strange events.

“Equally evil twin”

The precise cause is poorly understood but, study-by-study, experts in chemical and physical oceanography, biogeochemistry, marine biology, ecology and physiology are building a picture of the problem.

They theorize that acidification is spurred by a rapid increase in the amount of carbon dioxide taken up by the ocean, which sets off a chemical reaction that sours the waters. Scientists estimate that the world’s seas are 30 percent more acidic than they were before the industrial revolution 200 years ago.

Top marine ecologist Jane Lubchenco, who’s on leave from OSU to head the National Oceanic and Atmospheric Administration, calls ocean acidification the “equally evil twin” of climate change. Both involve excess carbon dioxide and both are inhospitable to life.

Readings taken out in the center of the Pacific show fluctuations around an average that is stepping ever upward, said George Waldbusser, a professor of ocean ecology and biogeochemistry at OSU. But the coastline of Oregon and Washington see higher levels of acidity because deep ocean currents drive cold, acidified waters from the east Pacific to the west.

Each May and June, winds along the Oregon Coast switch directions and begin shoving warm surface waters away from the shore, and that allows upwellings of those cold deep waters, which are devoid of oxygen and dangerous to sea life.

Scientists call it “hypoxia,” which means devoid of oxygen. Fishermen call these areas “dead zones” because the sea life that can swim away does and those creatures that can’t die.

In 2006, a dead zone off Oregon covered 1,800 square miles of ocean and lasted for four months, according to an OSU report.

This and other “severe episodes” make Oregon an excellent research subject, OSU assistant professor Francis Chan said at the most recent meeting of the governor-appointed West Coast Ocean Acidification and Hypoxia Science Panel.

Shells and brains

In the past half dozen years, science has focused on the effect of acidification on Northwest marine life, including oysters, pollock and tiny sea snails called pteropods.

Oyster larvae strain to make their protective shells in acidic waters and if the pH — scale of acidity and alkalinity in water — drops too low they die. Any other shell-building sea creature is vulnerable to the same problem.

“I am totally worried about it,” Portland-based Nature Conservancy ecologist Dick Vander Schaaf said. “You need to have juveniles to have more oysters. We’re very concerned about barnacles and their ability to form shells.”

Besides young oysters, shell builders include clams, abalone, scallops, sand dollars and sea stars. Crabs, too, build skeletons on the outside, so they could eventually be harmed.

Steve Rumrill, the shellfish program leader at the Oregon Department of Fish and Wildlife, worries about razor clams, mussels, Dungeness crab and red sea urchins.

Acidification also affects tiny organisms that float in the waves and serve as feed stock for fish — of all sizes — and even whales.

Rumrill, for example, worries about the microscopic larval form of Dungeness crab, which hang in the water column and feed coho salmon and gray whales. And pteropods dissolve when sea water gets too acidic, studies show. They are a chief staple of pink salmon.

“We are really in the infancy of understanding the extent of this problem — and it’s one that’s going to outlast all of us,” Rumrill said.

An early study on how corrosive waters affect fish was done in Australia on clownfish, like Nemo. The orange-and-white fish normally stick close to protective reefs, but in acidic waters they wander, including into the jaws of predators.

Newport-based scientist Thomas Hurst ran tests on juvenile walleye pollock at the Hatfield Marine Science Center. In acid waters, their brain signals were so scrambled that they couldn’t seem to recognize their regular foods. The result ultimately may be bad news for surimi eaters.

For fishermen, the news is strange and unsettling. Newman’s Fish Co. owner Dwight Collins wearies of the trail of news stories that follow each new discovery.

“This whole climate change, and such, some days I don’t even want to read about it because it is so scary,” he said.

Whiskey Creek discovery

The big break in scientific understanding of ocean acidification, though, happened in an oyster hatchery on the north Oregon Coast over the past five years. Hatcheries raise larval oysters in mammoth tanks until they form shells and can be planted in the ocean to grow to harvestable size.

But the larvae at Whiskey Creek Shellfish Hatchery at Netarts Bay, near Tillamook, inexplicably began dying at an alarming rate — 70 to 80 percent — each year for three years, said Waldbusser, the OSU professor.

The oyster die-offs at Whiskey Creek were dire for the entire $100 million West Coast oyster industry, he said.

“Most of the independent growers on the West Coast get their oyster larvae from that hatchery,” Waldbusser said.

“Growers would call up the hatchery and say, ‘We want seed’ and they had to tell them, ‘We don’t have any.’ Imagine if you were growing corn and you called up the seed supplier and they said, ‘Sorry, we don’t have any corn for you to grow.”

At first, the hatchery thought it was a disease that was killing the larvae. But treatments didn’t help. The hatchery’s scientist, Alan Barton, had a hunch that the acidity of the sea waters from Netarts Bay that supplied the hatchery’s tanks was killing the larvae.

He contacted OSU chemical oceanographer Burke Hales, who in 2010 lent the hatchery monitoring equipment that could test the acidity of the waters. Subsequent experiments found that treating the tank waters with sodium carbonate, basically Tums, reduced the larval deaths.

With OSU’s monitoring equipment, the hatchery learned to react when the pH started dropping into the acidic zone. Measurements over time helped it pinpoint hourly, daily and monthly fluctuations in acidity.

“Funny story,” Waldbusser said, when Hales asked for return of the (OSU) equipment for a research project, “the hatchery basically said, ‘Too bad we’re keeping it.’”

The hatchery’s misfortune brought critical insights to the scientists.

“There’s a window of time that (larvae) appear to be very sensitive to acidification, but if there is enough carbon dioxide in the water, even the later stages of larvae are going to be sensitive,” Waldbusser said. At some point on the pH scale, the shells of adult shellfish would be compromised, he said.

Washington takes note

The discovery in the Whiskey Creek tanks was the first straight-line connection between ocean acidification and damage to marine life — and demonstration of harm to a food source and an industry. Losses to oyster growers were on the order of $100 million, Waldbusser said.

“The work that we’ve been doing here in Oregon at the hatchery has helped really pave the way for a lot of other places to start addressing the issue,” he said. “I’m really proud of that work we’ve done.”

The Northwest shellfish industry — the bulk of it located on Puget Sound and Willapa Bay in Washington — took the lessons at Whiskey Creek to heart. In February 2012, then-Washington Gov. Christine Gregoire appointed a Blue Ribbon Panel on Ocean Acidification that wrote an action plan to combat the problem.

The Washington Legislature, based on the panel’s recommendations, invested $1.82 million in a new center on ocean acidification at the University of Washington to study the problem and aid shellfish growers.

But some oyster growers were too worried to wait around for science. Goose Point Oyster Co. in Willapa Bay, for example, didn’t want to rely on just the Whiskey Creek hatchery. The company, instead, built its own hatchery at Hilo, Hawaii, far away from upwellings and dead zones. When the seed oysters are ready, the company ships them home to Willapa Bay.

Search for solutions

The hunt for immediate ways to protect the Northwest shellfish industry is on.

Scientists want to be able to make short-term predictions about when acidification is on the rise so hatcheries can turn off their water intakes or otherwise protect their brood.

The Washington panel recommended a selective breeding program for shellfish aimed at creating new breeds of oysters that are resistant to acid waters.

Another strategy: oyster shell recycling.

In acidic waters, the shells, which contain calcium carbonate, slowly dissolve and buffer the waters around the seeded oysters — again it’s the “Tums effect,” Waldbusser said.

Shell recycling projects that collect shells from oyster houses and seafood processors have existed for years in Maryland, Virginia and most recently in Louisiana, where New Orleans restaurants contribute mountains of shells. Northwest oyster shells generally go to landfills.

The Washington panel debated introducing shell recycling to the Northwest, but there’s an issue that made participants wary. It’s herpes, basically, Waldbusser said. California oyster growers have been plagued with the virus, but it hasn’t spread to the Northwest.

Imported California oysters shells could get in the mix and infect Northwest oysters.

“It’s a real issue. You don’t want to contaminate or infect populations in Washington or Oregon,” Waldbusser said. Recyclers on the East Coast exposed recycled shells to sunlight for months before returning them to the sea, but that treatment is not yet proven to stop disease, Waldbusser said.

Overall, these short- term steps might help a bit with rising acidity — the Washington panel referred to them as “buying time.”

“But that’s only going to carry us so far,” Waldbusser said. “Fundamentally, at the base of it, we have to address carbon dioxide emissions. That’s not going to change.”

The increased carbon dioxide in the ocean is related to increasing concentrations of carbon dioxide in the atmosphere, studies suggest.

Waldbusser is not prepared to pin the problem on climate change caused by greenhouse gases created by burning fossil fuels — mostly in car engines — but time will tell.

“There’s predictions that the timing and intensity of upwellings will become worse with climate change on our coast,” he said.

The Washington panel doesn’t mince words: It’s No. 1 conclusion is that carbon dioxide emissions are the most significant driver of ocean acidification.

The solutions are the same ones recommended for curbing climate change: large scale deployment of plug-in vehicles, car sharing, mileage-based insurance, low-carbon fuel standards, transportation planning, energy efficiency standards, weatherization and solar panels.

Source: http://www.registerguard.com/rg/news/local/30407375-75/ocean-waters-acidification-coast-oregon.html.csp

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