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New study shows ocean acidification affects razor clam development

Pacific razor clams being held in a tank.
Marina Alcantar
Courtesy of Marina Alcantar
Pacific razor clams being held in a tank.

Harvesting razor clams is a beloved activity for many Alaskan families, especially in Cook Inlet. The Alaska Department of Fish and Game manages a fishery for the clams in the Ninilchik area, but it closed in 2015 due to declining populations. The fishery opened back up last year, but officials say it’s unlikely to reopen for the foreseeable future.

Marina Alcantar is a doctoral candidate at the University of Alaska Fairbanks. She says after talks with professors, they realized how little razor clams have been studied.

“As we moved forward, it became kind of shocking how much we didn't know about razor clams, especially considering how much they're loved, especially in Alaska,” she said, “and so it just really became kind of a mission to figure out some of their works, and how they will respond under future ocean acidification conditions.”

Alcantar collected clams from western Cook Inlet and transported them to the Alutiiq Pride Marine Institute in Seward for the study. She and the other researchers looked into the effect of ocean acidification on the early development of razor clams in Cook Inlet.

Marina Alcantar squatting behind tanks with buckets and tubing. The tanks are part of the experiment testing the effects of ocean acidification on the shell development of Pacific razor clams.
Cale Miller
Courtesy of Marina Alcantar
Marina Alcantar squatting behind tanks with buckets and tubing. The tanks are part of the experiment testing the effects of ocean acidification on the shell development of Pacific razor clams.

Ocean acidification happens when greenhouse gasses go into the atmosphere and raise carbon dioxide levels. When this happens, carbon dioxide also goes into the ocean and lowers its pH. A lower pH makes the ocean more acidic, and can have a negative impact on many kinds of marine life.

The study looked at the effect of high levels of ocean acidification, as well as changing levels of acidification. The higher levels of acidification simulate what future ocean conditions may look like. However, in many parts of the ocean, the level of acidification goes through a cycle of changes. These changing levels can now be replicated in a lab. While very few studies have used this method, it could provide a more realistic picture on ocean acidification’s effect on marine life.

Amanda Kelley is an associate professor at the UAF College of Fisheries and Ocean Sciences. They say this varying acidification better reflects the clam’s living conditions in Cook Inlet.

Amanda Kelley holding a razor clam.
Paula Dobbyn
Courtesy of Marina Alcantar
Amanda Kelley holding a razor clam. Kelley and other researchers looked at the effect of ocean acidification on Pacific razor clams.

“We know that razor clams inhabit the upper subtidal regions of the nearshore environment, and in Alaska, it happens to be super variable,” they said.

The study found that the acidification affects how the clam forms its shell. Razor clam shells are made of calcium carbonate, which is also found in chalk and limestone. This can be formed in different structures that have varying levels of stability.

The study used a scanning electron microscope – an instrument that shoots electrons at a surface to detect its shape. They also used a laser system typically used for weather science to analyze the mineral structure in the shells. Alcantar says clams in high and changing acid levels have a different structure than the control group.

“When we combined that data, it really pointed out to us that we are using some of the rarer and more vulnerable to dissolving versions of calcium carbonate,” she said.

She says as the shell forms in more and variable acidic conditions, they’re more likely to dissolve. As adults, the shells are mainly made up of aragonite, which is stronger but still susceptible to dissolving.

In addition to the results of the study, Kelley says doing this research gives a better understanding of basic information about the clams.

“We really knew nothing about the early life history of razor clams until this study was carried out,” they said.

Alcantar says this information will help to regulate and protect future populations, but this is just the beginning.

It just means a lot, and I feel like, you know, it's a way for me to use my, my nerdiness for marine biology to serve my community,” she said.

Alcantar says she’s waiting to publish another paper diving deeper into razor clams, and may look into developing ways to grow razor clams in hatcheries.

Jamie Diep is a reporter/host for KBBI from Portland, Oregon. They joined KBBI right after getting a degree in music and Anthropology from the University of Oregon. They’ve built a strong passion for public radio through their work with OPB in Portland and the Here I Stand Project in Taipei, Taiwan.Jamie covers everything related to Homer and the Kenai Peninsula, and they’re particularly interested in education and environmental reporting. You can reach them at to send story ideas.