The Oregon Ocean Acid Test

By Jim Yuskavitch

On a cold, windy afternoon last November, Dick Vander Schaaf stood on the beach at Cascade Head near Lincoln City anxiously scanning the outgoing tide. He leaned on a shovel he hoped he wouldn’t have to use.

He was looking for a black and white PVC tube that had been bolted to a rock in the wave-tossed intertidal zone. Inside the tube was a sensor for measuring water temperature and pH, the chemical yardstick of acidity.

The tube had reportedly been buried in up to a yard of sand by wave action, and Vander Schaaf, the associate coast and marine conservation director for The Nature Conservancy, Oregon office, wasn’t keen on having to dig for it.

Then his face brightened. “There it is!” he called. Wading in knee-deep water, he brought the tube and its contents safely back to dry land. He would send the sensor and its stored data to Francis Chan, an associate professor and senior researcher in Oregon State University’s Department of Integrative Biology. Oregon’s coastal waters, says Chan, are a world hotspot of ocean acidification.

Chan has been monitoring pH levels off the Oregon coast for the past two years. Working with a network of volunteers like Vander Schaaf, he has seven monitors strategically placed in the intertidal zones at the state’s five marine reserves — Cape Falcon, Cascade Head, Otter Rock, Cape Perpetua and Redfish Rocks. Ocean acidification is a growing influence on Oregon coastal waters, Chan has found, along with indications there may also be some “safe zones” for marine organisms susceptible to its effects.

Sometimes called “climate change’s evil twin,” a phrase coined by Oregon State’s Jane Lubchenco, ocean acidification is an insidious and unseen effect of rising carbon dioxide (CO₂) levels in the atmosphere. The oceans have always absorbed CO₂ from the atmosphere, but as levels of the greenhouse gas have climbed, primarily the result of fossil fuel burning, the oceans have taken in ever-higher amounts, leading to shifts in ocean chemistry.

Organisms from oysters to corals are considered sensitive. Over the past 200 years, according to the National Oceanic and Atmospheric Administration, average ocean-wide pH has dropped from 8.2 to 8.1. That may not sound like much, but on the pH scale, it amounts to a nearly 30 percent increase in acidity. Other researchers have found that highly acidified water can cause calcium shells made or used by many marine creatures to be harder to build or to dissolve. The net effects may be felt up and down the food chain. Animals in the intertidal and near-shore zones, including economically important species such as oysters and crabs, may be at risk.

A Path to Lower pH

Chan arrived at OSU in 2001 to conduct post-doctoral research on ocean hypoxia — water with low oxygen levels — and has since become an expert on the subject, including its intensity, duration, where it occurs and how it impacts marine organisms. His interest in biogeochemistry (the study of the physical, biological, geological and chemical processes in the environment) led him to start the Oregon coast ocean acidification monitoring study in 2016. Chan is also affiliated with PISCO (the Partnership for Interdisciplinary Studies of Coastal Oceans), a research collaborative including OSU, Stanford University and the University of California at Santa Cruz and at Santa Barbara. PISCO scientists study the near-shore ocean environment from Baja California to British Columbia.

“The ocean may look the same, but the water is changing, especially on the Oregon coast,” says Chan. Here’s why the Oregon coast is particularly vulnerable to acidification and thus an important place to study ocean chemistry.

Much of Oregon’s coastal water originates in the North Pacific off Japan in two cold, deep-water currents. One takes about 10 years to reach Oregon, while the second takes a more circuitous path and nearly 50 years to deliver its water here. Because cold water can hold higher concentrations of CO₂ than warmer water, these currents start off with increased CO₂ levels. As they slowly flow toward the U.S. West Coast, biological activity by organisms living in that water layer — zooplankton, phytoplankton and other microorganisms — continually generates CO₂ until, by the time the water rises to the surface off the Oregon coast, its CO₂ level has increased dramatically. Once that water is finally exposed to the atmosphere after decades in the deep, it begins absorbing even more of the greenhouse gas. “Together, those two are putting us through some chemical

Science in Action

In addition to collecting data, Chan also involves coastal community residents in the research. One of his goals is expanded public awareness about ocean acidification and local adoption of solutions. Beginning with volunteers from the Redfish Rocks Community Team — a group of Port Orford residents who act as stewards for the Redfish Rocks Marine Reserve — he has expanded his volunteer network of citizen scientists to include other marine reserve community teams, The Nature Conservancy and the Surfrider Foundation.

“Francis gets credit for identifying the need to reach out to community groups and identify people who would be able to help,” says Tom Calvanese, manager of OSU’s Port Orford Field Station, who helps coordinate the Redfish Rocks Community Team volunteers.

Using their local knowledge, these citizen scientists help Chan pick the best locations in the intertidal zones to place the monitors. During the spring-to-fall field season, they remove the sensors every four weeks and send them to Chan, who downloads the data. Chan installs a new sensor in its place and sends it back to the volunteer. Because everything is self-contained, the citizen scientists don’t have to worry about making mistakes that might compromise the data.

“The monitoring is helping us find out things about ocean acidification on the coast that we didn’t know before,” adds Calvanese. “It’s an example of the benefits of a partnership between the university and the community.”

One of the lessons they have learned is that ocean acidification is not uniformly spread in Oregon’s coastal waters. The headlands and bays, continental shelf and other features both above and below the water’s surface affect currents and chemistry, feeding more acidic water to some parts of the coast and not to others. Chan’s sensors have detected some of the lowest coastal pH levels off the Cape Perpetua Marine Reserve. In contrast, the Redfish Rocks Marine Reserve appears to be less affected by ocean acidification.

Looking for Refuge

That’s important because, in addition to monitoring ocean acidification levels over time, Chan wants to know if protected marine areas might help mitigate some of the future impacts. “We want to know if there are some marine reserves that might act as refuges for fish and other organisms,” says Chan. This kind of information is also being provided to the Oregon Department of Fish and Wildlife to help it better manage the nearshore environment.

Another component of Chan’s research, and equally important, is public outreach. Chan wants to share the results of his research so more people understand ocean acidification and other changes that are happening to our oceans. He wants science to empower citizen action. “There is so much skepticism about science these days,” says Charlie Plybon, Oregon program manager for the Surfrider Foundation, one of Chan’s partner organizations. “The more we can energize people with science, the more scientific information we can bring to the public, the better.”

The Surfrider Foundation has developed a website about ocean acidification on the Oregon coast and Chan’s research. The Redfish Rocks Community Team is developing a K-12 curriculum about ocean acidification, producing a film on the subject and conducting teacher training. OSU is also at work on teaching curriculums and helping scientists better communicate their research to the public.

Back on the beach at Cascade Head, a marine reserve that Chan has found to be less affected by ocean acidification, Vander Schaaf, sensor in hand, watched the now incoming tide splash against the rocks. “The conservation importance of refugia with lower ocean acidification effects can’t be overstated,” he says. “The ocean acidification monitoring may give us the opportunity to put measures in place in these areas to help conserve the organisms and habitats there.”

Human activities continue to affect the very chemistry of the ocean, but Chan and his network of volunteers are on the forefront of citizen science. Using the knowledge they create, they are looking for strategies to help protect the ocean and its creatures from this profound and growing environmental challenge.

Jim Yuskavitch is a freelance writer and photographer. He lives in Sisters.