Oyster farming lines at Lambert Shellfish on the Eastern Shore in Virginia on May 28, 2026. Katherine Hafner/WHRO News
Shellfish farmers are working with the Virginia Institute of Marine Science to better understand the looming issue.
Shellfish such as clams, crabs and oysters need tiny building blocks called calcium carbonate ions to grow and thrive.
These particles are essential to build sturdy shells that protect marine creatures from predators – and make them more appealing for human diners.
But rising acidity tied to climate change is making it harder for shellfish to access those fundamental building blocks.
The issue caught officials’ attention in the late 2000s when acidic corrosion caused mass die-offs of baby oysters in the Pacific Northwest.
Researchers at William & Mary’s Batten School and Virginia Institute of Marine Science have teamed up with local shellfish farmers to learn more about how changing conditions could impact the aquaculture industry in coastal Virginia.
“We know the threat exists,” said Emily Rivest, an associate professor in ecosystem health at the Batten School and VIMS. “This gives us the opportunity to try to get ahead of it to understand how to build our resilience and prevent those kinds of dramatic negative impacts.”
The project is funded by a $1.2 million grant from the National Oceanic and Atmospheric Administration’s Ocean Acidification Program.
The ocean absorbs about a third of the climate-warming carbon dioxide humans release into the atmosphere. That causes a cascade of chemical changes underwater, including reducing pH levels.
For millions of years, the ocean’s pH remained relatively stable at 8.2 on the pH scale, which ranges to 14, the most basic. Since the start of the Industrial Revolution, it has dropped to 8.1. Because the scale is logarithmic, that represents a nearly 30% increase in acidity, according to NOAA.
In much of the Chesapeake Bay, the rate of change is happening even more quickly, particularly in the middle, VIMS previously found.
One factor is freshwater. When freshwater surges into the bay, it lowers the amount of salt in the water, which makes it more susceptible to acidity, Rivest said. That has sometimes affected restored oyster reefs on the western side of the Eastern Shore.
Pollution from nutrients washing off land into the bay compounds the issue by triggering algae that produce carbon dioxide when eaten by bacteria, Rivest said.
Luckily, natural variability in the Chesapeake Bay “has shaped the eastern oyster to be a very tough and resilient species,” Rivest said.
Lab tests indicate local oysters are “much more tolerant of acidification” than out West. The question is: What is their breaking point?
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WHRO, 29 May 2026. Full article.
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