By Christopher Dunagan, Puget Sound Institute
The dangers of ocean acidification — an intrinsic feature of climate change — are coming early to Washington state, causing measurable harm to sea life, according to a new report that outlines a state strategy for pushing back against the problem.
The report, titled “Ocean Acidification: from knowledge to action,” updates and expands upon strategies first developed in 2012 by the Washington State Blue Ribbon Panel on Ocean Acidification.
“Ocean acidification threatens Washington shellfish, fisheries industries, and the coastal communities that depend on them,” said Gov. Jay Inslee in a prepared statement. “Our state is on the front lines of responding to these threats.”
In some ways, Washington State is at the mercy of natural and human forces operating on a global scale. Carbon dioxide in the atmosphere is absorbed into ocean waters, forming carbonic acid. In the Pacific Ocean, deep waters circulate for decades, becoming more acidic, until they rise near the surface along the West Coast and enter Puget Sound.
As a result, Washington state has gained worldwide recognition as a hotspot for ocean acidification problems — much like some South Pacific islands are being lost to sea-level rise and the Arctic landscape is threatened by melting ice and permafrost.
“By accident of geography, we have this upwelling that … forces us into dealing with ocean acidification before almost anywhere else on the planet,” said Jay Manning, chairman of the Puget Sound Leadership Council. “I don’t believe I’m exaggerating when I say that Washington is leading the world in terms of science and monitoring…”
Although ocean acidification is a global problem, new studies have revealed that Washington state residents are not powerless against it, according to the new report. It turns out that local sources of carbon dioxide in the air exacerbates the problem for Puget Sound, while excess nutrients from human sources adversely change the water chemistry in certain locations.
Ultimately, the solution to ocean acidification involves reducing carbon dioxide emissions worldwide, but it is clear that local actions can make a difference, said Manning, who attended the United Nations Climate Change Conference last month in Bonn, Germany. Manning also is a member of the Marine Resources Advisory Council, which developed the plan for dealing with ocean acidification.
“It is all about buying time and hoping that we, as a species, can reduce CO2 emissions quickly enough across the entire planet to shift the trend,” he said. “That’s one reason we are being viewed as leaders by ocean nations like Fiji. The science and monitoring are super important, but we are also taking actions.”
Ongoing studies have shown that increasing carbon dioxide levels in the water have reduced the availability of calcium carbonate for organisms that need the mineral to build and maintain their shells and other hard body parts.
While conditions vary from time to time and place to place, recent studies have shown that corrosive waters in Puget Sound are able to dissolve the shells of free-swimming snails called pteropods.
Laboratory studies have shown similar effects on krill, which are tiny crustaceans, and bottom-dwelling animals called foraminifera. Since these tiny creatures are eaten by fish and many other organisms, their loss can ultimately affect the entire food web right up to salmon and killer whales.
Shellfish biologists have learned that increased acidity also prevents oyster larvae from forming proper shells, which can affect entire oyster populations. In Willapa Bay on the Washington Coast, conditions were favorable for oysters only a few weeks each year from 2012 through 2014 and not at all in 2011. In pre-industrial times, experts say favorable conditions lasted for months.
The effects of increased acidity are serious enough for sensitive organisms, but they often face the dual effect of low oxygen conditions at the same time. Increasing water temperature, another effect of climate change, has been found to make the problem even worse.
Nitrogen from sewage-treatment plants, septic systems, fertilizers and other sources has been shown to foster the growth of algae, which eventually die and sink to the bottom. The dead algae are consumed by bacteria, which use up the available oxygen while releasing carbon dioxide and increasing the acidity of the water. The combined effects of low oxygen and elevated acidity can be dire for bottom-dwelling creatures.
Shellfish hatchery operators are learning to adapt to periods of increased acidity by monitoring water conditions and adjusting for proper chemistry in their growing tanks, according to the report. A three-day forecast model developed by the University of Washington provides an early warning of acidity, temperature, oxygen levels and other conditions for coastal waters. The next step is to extend the model into Puget Sound.
In other efforts since 2012, researchers were able to show that eelgrass beds can absorb enough carbon dioxide to reduce the effects of acidification. Eelgrass, an important habitat for nearshore species, helped juvenile oysters grow 20-25 percent faster when they were inside rather than outside the eelgrass beds.
Kelp may also play an important role. Researchers are growing kelp at a site near the Hood Canal bridge to determine how much carbon dioxide and nitrogen can be soaked up by the leafy seaweed (kelp is a member of the algae family), which also provides habitat for multiple species. The study will determine if the kelp can be harvested for food, fertilizer, feed and other products.
Other studies are under way to measure the effects of nitrogen coming into Puget Sound from various sources. A computer model, called the Salish Sea Model, is being used to see if upgrading sewage-treatment plants and taking other steps to remove nitrogen can improve oxygen conditions and reduce ocean acidification in Puget Sound.
Meanwhile, Gov. Inslee has announced that he will push ahead with the idea of a carbon tax to reduce carbon dioxide emissions into the atmosphere. If successful, the reduction could have benefits for Puget Sound as well as the world’s climate, according to the report.
Washington has joined forces with California, Oregon and British Columbia to battle ocean acidification. Last year, these states went international to form a network of governments and other organizations called the International Alliance to Combat Ocean Acidification.
“Global and local carbon dioxide emissions, as well as local nutrient sources beyond natural levels, are significantly altering seawater chemistry, Martha Kongsgaard, chairwoman of the MRAC, said in a written statement.
“We are the cause for the rapid accumulation of 30 to 50 percent of the enriched CO2 in surface waters in Puget Sound and 20 percent of enriched CO2 in deep waters off our shores,” she said. “Washingtonians understand what is so dramatically at stake. We are not standing by waiting for someone else to inform or rescue us.”
Christopher Dunagan is a senior writer at the Puget Sound Institute.