Decades ago, some scientists believed the oceans could absorb much of the carbon dioxide the world’s fossil fuel-driven economy was spewing into the atmosphere. The oceans, early studies suggested, would serve as a so-called carbon sink, drinking up that carbon and storing it for perpetuity.

Now, leading scientists in the region say, those oceanographers were both right and wrong. The oceans did absorb much of that carbon. But not for perpetuity.

Today, according to leading researchers, ocean acidification — as this far-reaching change in the ocean’s chemistry is called — is occurring at a rapid pace. Oceanic upwellings are delivering carbon-rich waters to coastal zones, making the sea corrosive to oysters, mussels, crabs and other crustaceans and leading to indications that the ocean’s food chains are beginning to unravel.

The chemical change in the world’s oceans is happening much faster than some of the best models had predicted, scientists at the University of Washington and the National Oceanic and Atmospheric Administration (NOAA) say. And ground zero for the phenomenon is Puget Sound, an inland sea that’s facing a kind of triple punch — upwellings from the ocean depths that carry carbon, atmospheric carbon heavily influenced by regional weather patterns and polluted run-off from fertilized yards, parking lots, horse pastures and failed septic systems.

Shellfish growers — such as Taylor Shellfish Farms, the largest bivalve grower in the country — are already seeing the impact. In 2008, the company’s larvae production — the seeds that became oysters — fell by 60 percent at its three regional hatcheries, according to Bill Dewey, public policy director at Taylor Shellfish. In 2009, larvae production was off by 80 percent.

The situation, said Jan Newton, a UW oceanographer and a member of a statewide blue ribbon panel that put out a headline-garnering report last fall, “is serious. I think the important thing to consider is that shellfish growers are seeing some impacts now.”

“What’s at risk,” she added, “is the exact food web as we have it and know it right now. Trying to predict winners and losers and how that’s going to ricochet through the food web is really difficult. … But will we have the same food web that we know and love in the same quantities as we do now? Probably not.”

Puget Sound, added Betsy Peabody, head of the Puget Sound Restoration Fund and another member of the blue ribbon panel, is particularly threatened.

“There’s the big global driver — CO2 emissions. Then there’s the regional phenomenon, the coastal upwellings. Then there are the local drivers, our land-based activities. It’s a triple storm of factors. Each of them is exacerbating and driving ocean acidification,” she said.

But recent research by NOAA’s Pacific Marine Environmental Laboratory suggests that local sources — the CO2 residents and businesses in the region are putting into the atmosphere — is a bigger factor in Puget Sound’s acidification than global carbon emissions. A monitor placed on the Space Needle has found spikes in CO2 during rush hour — an increase in carbon particulates significantly higher than the current global average, said Adrienne Sutton, a research scientist with the Pacific Marine Environmental Laboratory. Researchers now believe 75 percent of the carbon getting into Puget Sound stems from local air pollution, she said.

Sutton said she finds that information encouraging. “It means we can definitely have an influence.”

Simple acts — such as using public transportation and avoiding driving during rush hour — can make a difference, she said.

Even so, the ongoing research about ocean acidification is sobering to conservationists on Vashon, surrounded as it is by Puget Sound and a place where orca whales, the top of the region’s food chain, have become an iconic and celebrated species.

What’s particularly sobering, said Tom Dean, the head of the Vashon-Maury Island Land Trust, is the realization that the region is experiencing the results of decades of fossil fuel-consumption — what one scientist called a package we mailed to ourselves years ago and that is just now being delivered.

“There’s a growing realization that the ship of climate change has sailed, and even radical reductions in CO2-producing fuels are not necessarily going to turn that ship around,” Dean said.

Vashon is buffered from some of the anticipated impacts of climate change that have gotten the most attention, he noted. “We’re not reliant on a snow pack for our water. We don’t have a lot of low-lying land, like Kent, which will be completely flooded one day. We don’t have bugs eating our forests — yet. So far, so good,” he said.

But what’s happening to Puget Sound — unseen to many people — is an impact islanders will eventually feel, he predicts.

“If crustaceans disappear from the food chain in Puget Sound, that probably means a collapse of the food web. And that means your top predators may become squid and jellyfish. … No more orcas. No more crabbing. No more salmon-fishing,” he said.

“Vashon has a lot going for it in the face of climate change, especially if we can learn to feed ourselves,” he added. “But when it comes to ocean acidification, I just can’t find a silver lining.”

The issue recently came up at a meeting on Vashon, where Dean and several other conservationists got together to discuss ways to engage citizen scientists in the protection and restoration of the Maury Island Aquatic Reserve, a state-managed reserve that wraps around Maury and takes in all of Quartermaster Harbor. Preserve Our Islands was one of two organizations that received a federal grant to engage residents in the aquatic reserve’s health, and some at the meeting thought it might be a good idea to have citizen scientists explore the impact of ocean acidification on the reserve.

“No one’s really thinking about how you manage for this,” said Bob Fuerstenberg, an ecologist who recently retired from King County and who was at the meeting. “It’s a huge bio-regional issue. What do you do? How do make these waters more resilient?”

John “Oz” Osborne was also at the meeting, another islander who brought information to the table. Osborne, a software engineer, works for the Pacific Marine Environmental Laboratory and was recently tasked with overseeing the quality of the data coming into the lab from two buoys that are measuring Puget Sound’s chemistry.

But as the group discussed the threats to the reserve, they realized that Quartermaster Harbor is not an under-studied body of water and that research from citizen scientists likely wouldn’t make a difference, Dean and others said. “In fact, it’s the one place where we have a lot of information,” Dean said.

What’s more, it’s hard to know what the goal of such a project would be when the region — and the nation — has still not put in place meaningful measures to try to limit carbon emissions. Noting the regional debate over a coal-export terminal north of Bellingham, Dean added, “Can dying invertebrates stop coal trains? That’s the question.”

The seriousness of the situation was first identified by shellfish growers in Washington and Oregon who initially thought their oyster larvae were failing to survive because of a naturally occurring marine bacteria, said Dewey with Taylor Shellfish. In 2008, an engineer for one of the hatcheries near Tillamook, Ore., noticed the connection between oyster die-offs and summertime peaks in the north wind, which caused upwelled water to flood the hatcheries’ tanks.

The industry was able to sound the alarm, Dewey said, adding wryly, “Ours are the first organisms to have a spokesman for them.”

Since then, much has happened in both the scientific and political world. The oyster industry, with the help of Sen. Marie Cantwell (D-Washington), got funding that enabled hatcheries to install sophisticated monitoring equipment that measures the carbon levels in the water and change their practices when those levels are high. Using a metaphor another oysterman coined, Dewey said, “That monitoring equipment was like putting headlights on the car. We could see the chemistry in the water that was coming our way.”

Another significant development was then-Gov. Chris Gregoire’s appointment of a blue ribbon panel to take a comprehensive look at ocean acidification, hailed as a pioneering effort in November, when the panel issued its 156-page report as well as a slew of recommendations to address the situation.

Sen. Kevin Ranker (D-Orcas Island), a member of the blue ribbon panel, put forward a bill a month ago that would begin to coordinate the state’s response to ocean acidification. The bill died in the Senate but has been added as an amendment to another bill, Dewey said. “In effect, it’s still alive.”

Like Dean, Dewey sees the situation facing the region’s marine waters as dire. “We’re doing a chemistry experiment in the ocean on a world-wide basis,” he said.

But he takes heart in the fact that Gov. Jay Inslee is deeply concerned about climate change and ocean acidification — “probably the most informed governor in the country on both of these issues,” he said.

Peabody, with Puget Sound Restoration Fund, also says she finds hope in local actions that are making a difference. The organization, for instance, installed a floating field station in inner Quartermaster Harbor with funding from King County two years ago. The raft, which has 60,000 mussels suspended from it, is part of an effort to determine if the bivalves can help reduce the bay’s nutrient-loaded waters. Nutrient pollution results in more CO2 in the water. Mussels, however, take in those nutrients and convert them into protein, filtering out particulates and cleaning the water in the process.

The research so far is promising. “We need more data,” Peabody said. “But the Quartermaster Harbor project does show that shellfish production provides a helpful piece in the mix of strategies we can use to mitigate nutrient pollution.”

Peabody, meanwhile, says she believes only when people realize what’s at stake will they begin to take steps that can make a difference. And what’s at stake, she said, are several kinds of food — oysters, clams, mussels and ultimately salmon — that many people enjoy.

“The water around us is changing, and the ability of this place to feed us is threatened by what we’re doing,” she said. “That, fundamentally, is how we relate to a place — through food. It’s a very clear measure of whether or not this place is healthy.”