When seawater chemistry shifts, marine life pays the price.
Ocean acidification makes it harder for shell-building organisms to grow and survive. That stress can ripple through food webs—changing habitats, weakening ecosystems, and threatening coastal economies.
Shellfish are the early warning system
Oysters, clams, mussels, scallops, and many plankton species build shells from calcium carbonate. When seawater becomes more acidic, carbonate ions become less available—so shell formation gets harder.
Slower shell growth
Building and maintaining shells takes more energy, leaving less energy for growth and reproduction.
Larvae are most vulnerable
Early life stages need to form shells quickly. Acidification can raise mortality and reduce survival rates.
Weaker shells
Thinner shells can break more easily—making shellfish more vulnerable to predators and storms.
Impacts spread through marine ecosystems
Even organisms without shells can be affected. Acidification can alter behavior, growth, and survival—especially when combined with warming, low oxygen, and pollution.
Food webs shift
If plankton and shellfish decline, predators have less to eat—affecting fish, seabirds, and marine mammals.
Habitats weaken
Coral reefs and shellfish reefs support biodiversity. When they erode or fail to form, ecosystems lose complexity.
Stress stacks
Acidification + heat + low oxygen can be worse than any one factor alone. Real oceans face multiple pressures at once.
Why humans should care
Ocean acidification threatens seafood supply, coastal jobs, and the natural systems that keep coastal waters healthy. It also makes restoration harder—because organisms are trying to rebuild in more challenging chemistry.
Seafood + aquaculture
Shellfish farms and hatcheries can experience losses when intake water becomes corrosive to larvae.
Coastal protection
Reefs and beds reduce wave energy and erosion. Healthier ecosystems mean more resilient shorelines.
Water quality
Filter-feeders like oysters remove particles from water. When populations decline, water can get murkier.