Researchers tackle data gaps in ocean acidification impacts

  • Graduate Student Marina Washburn with the larval culture buckets containing razor clams at the Alutiiq Pride Shellfish Hatchery. (Photo/Courtesy/Marina Washburn)

SEWARD — Increasingly acidic oceans are expected to affect marine species on which fishermen of all stripes rely. One of the things that’s not known is how it’s exactly going to affect each individual species, particularly in Alaska.

A group of researchers from the University of Alaska Fairbanks is looking into the effect of ocean acidification on three clam species — littleneck and razor clams and cockles — that are important for subsistence and sport harvest in the state.

Entrenched in their research is a desire to know more generally about how ocean acidification is going to play out in the state.

“Our goal is really to define what those sensitivities are in the hope of managing these species,” said Amanda Kelley, an assistant professor of marine biology at the University of Alaska Fairbanks. “What we can say is that okay, if our data supports what is happening with these species, we know that (a specific species) is more sensitive to climate change effects.”

Kelley and two of her graduate students are working on research specific to how more acidic oceans will affect shellfish. For Marina Washburn, who is working toward a master’s degree in marine biology, there’s a personal connection, too: she grew up harvesting the once-plentiful razor clams on the beaches of Ninilchik and Clam Gulch.

Due to depressed populations, that fishery has been closed for four straight seasons.

Washburn successfully hatched razor clams this summer at the Alutiiq Pride Shellfish Hatchery in Seward, the first time it’s ever been done in a lab. Her project involves continuously bubbling a set amount of carbon dioxide into seawater, patterned after what scientists expect ocean conditions to be like by 2100. The project can be done all year because it’s done in a closed lab, she said.

The collapse of the razor clam fishery on the east side of Cook Inlet likely isn’t solely due to ocean acidification — the Alaska Department of Fish and Game has cited harvest pressure, poor survival, storm damage and unfavorable environmental conditions among the possible causes — but it could be playing a role. Even if it isn’t now, it could in the future, Washburn said.

“That sad truth about mollusks in in Alaska is that (the information available) is shockingly low,” Washburn said. “There is very little research. I think Alaska has a problem with not appreciating our resources like shellfish and fish until there is a problem.”

Researchers worldwide have been tracking a gradual increase in the acidity of the ocean, linked to an increase in carbon dioxide in the atmosphere. Essentially, the ocean absorbs more of the carbon dioxide from the atmosphere and breaks it down, absorbing the carbon molecules and creating carbonic acid.

Some of that carbonic acid breaks down, though, freeing hydrogen molecules and increasing the pH of the water, making it more acidic and raising a host of issues for marine animals adapted specifically to a less acidic ocean.

Shellfish are on the front lines of those risks. More acidic oceans can dissolve the calcium carbonate-based shells mollusks build to protect their soft bodies, exposing them to predation. Mollusks are important in the marine food chain — everything from fish to otters to sea stars predate on shellfish.

Many Alaskans also depend on shellfish for subsistence. Ashley Rossin, a marine biology Ph.D. student working with Kelley, is studying the impact of ocean acidification on littleneck clams and cockles, both of which have been traditional subsistence foods.

Out in remote coastal communities, where imported groceries are not as common and are more expensive, rural residents have relied on abundant shellfish for generations. That’s changed in the last decade or so, as populations of clams around the state have reportedly been in decline, Rossin said.

“(In research, rural populations have) said they don’t even know what to do, and the clam and chiton populations are so small but they need to continue to fish there because that’s what available to them, but they don’t want to fish them because they know it may not be good for them,” she said.

Her project includes looking at the water in beaches where littlenecks and cockles settle — called pore water — to see if the conditions there are different than the surrounding ocean and how that may affect them.

The two species occupy the exact same habitats but have opposite life history strategies, Rossin said — littlenecks grow slowly while cockles grow quickly.

“(Kelley) wanted to see what the difference in their responses would be,” Rossin said. “We’re going to see basically which one is the winner or the loser in this situation. The conditions that are there are kind of unknown … some people have hypothesized that the water in that sediment is actually more acidic.”

One of the frustrations all three mentioned was a lack of overall existing data both about existing shellfish populations and about the effect of ocean acidification on Alaskan species overall.

Kelley said there have been about six studies so far about ocean acidification’s effect on Alaskan marine animal species in Alaska. The work they’re doing on shellfish is the first of its kind in the state, she said.

“We are only measuring one variable in the lab,” Kelley said. “But what you start to do is develop a series of mounting evidence. The only thing we can do is accumulate evidence … Alaska is behind the curveball for research on climate change. Funding is definitely a big part of it. I have to submit grants (for research) and when I submit a grant, I have to compete with everyone else who wants to study seabirds.”

Rossin’s project includes a citizen science aspect using the Local Environmental Observation, or LEO, network and Epi Collect 5, asking individuals to record their observations about shellfish and shellfish harvests all over Alaska.

Alaska SeaGrant is supporting both projects, in part because of the importance of the clam species to harvest by the subsistence, sport and commercial sectors alike.

There is some baseline information being gathered around the state, though. In a back room at the Alutiiq Pride Shellfish Hatchery, shellfish biologist Jacqueline Ramsay is testing water samples from all across the Gulf of Alaska coast for their baseline water conditions to help track localized changes.

At first glance, it looks like she’s storing shelves and shelves of six-packs of beer. But those are actually the sample containers: she has citizen scientists gather water samples in cleaned, recycled beer bottles and mail them to her at the hatchery.

She then plugs them into a machine known as the Burke-o-lator — named for its creator, Burke Hales of Oregon State University — to continuously test them for water quality measures.

“What this machine does is it just constantly sips on (the water sample) and measures salinity and pH (among other metrics),” she said.

Alutiiq Pride Shellfish Hatchery, the only shellfish hatchery in Alaska, is an operation of Chugach Regional Resources Commission. Ramsay receives samples from many of the corporation’s member villages, from Seldovia to Eyak, with about three years of data on hand.

She’s working with several other researchers through to build baseline data on existing conditions in Alaska using these longterm data sets. Longterm data is important for gauging changes, establishing baseline conditions to work with on different species and locations.

“I think we alread know that pollock and crab and clams all react differently,” Ramsay said. “That’s why this is so important.”

Alaska is especially vulnerable to ocean acidification in the future, as colder water holds more gas and is more susceptible to changing pH. With Alaska’s dependency on healthy marine ecosystems for healthy fisheries and subsistence, being able to look forward and estimate impacts will be important, Washburn said.

“We’re kind of getting hit on both sides,” she said. “As terrible as it is, Alaska is a great place to study ocean acidification, because we are going to feel the effects of it.”

Elizabeth Earl can be reached at [email protected].

Updated: 
10/17/2018 - 10:37am

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