Researchers look into acidification in Chesapeake Bay
Changes in water chemistry could endanger shellfish like oysters and clams
Scientists are examining how ocean acidification interplays with estuaries like the Chesapeake Bay, a process that could put shellfish at greater risk.
Worldwide, seawater is becoming more acidic as it absorbs an increasing amount of carbon dioxide. Ocean acidification has been a concern for many as it posts a significant impact on marine life, commercial fishery and the
livelihoods of those who depend on it.
In a study published this week, a group of 16 scientists from seven universities and institutions looked into ocean acidification and nutrient loading, and their interactions within the bay.
In general, acidification is bad news for shellfish, because it reduces mollusks’ ability to build their shells.
Also, if the pH in the water becomes too low, meaning more acidic, that could affect the operation of a hatchery that grows oyster larvae, said Jeffrey Cornwell, a research professor at the University of Maryland Center for Environmental Science based at Horn Point Laborator y.
Considering the amount of investment put in projects like oyster restoration, Cornwell said the impact of acidification on shellfish is the biggest concern.
The study’s lead author, Wei-Jun Cai, a University of Delaware professor, said in large estuaries like the Chesapeake, the combined environmental and climate change
stressors make the bay more vulnerable, and the excess nutrients and increase in acidity may take a larger toll.
“Ocean acidification is happening, but how that process is going to play out with estuaries is less clear,” said Jeremy Testa, assistant professor at the University of Maryland Center for Environmental Science based at Chesapeake Biological Laborator y in Solomons.
“Every summer, in the bay’s deep water, there’s a reduction in pH,” meaning the water becomes more acidic, Testa said. But the answer of if there’s acidification in the bay “depends on where and when you look.”
Previous studies have indicated that acidification can be particularly serious in nutrient-rich coastal waters, such as the bay, which often contain areas with too little oxygen and high levels of carbon dioxide near the bottom, according to a University of Maryland press release.
In coastal waters, excessive nutrients from runoffs can stimulate an overgrowth of algae, which then sinks and decomposes in the water. That process uses oxygen in the water and creates excess carbon dioxide, leaving areas of water with little or low oxygen, hence creating dead zones and reducing pH in the water.
Testa said part of looking ahead for further research is to identify areas in the bay that are most vulnerable to acidification and how can an oyster aquaculture operation, for example, adopt to it or mitigate the impact.