Research Shows Growing Kelp Helps Reduce Ocean Acidification

giant kelp
Macrocystis pyrifera, which is commonly called giant kelp or bladder kelp. Photo: Claire Fackler, CINMS, NOAA.

Researchers at Stony Brook University in southeastern New York say their studies show that the presence of kelp, already recognized as a nutritious food source for people and marine life, significantly reduces ocean acidification, which is a result of climate change.

The study, led by Christopher Gobler and scientists at the Stony Brook University School of Marine and Atmospheric Sciences, also demonstrated that deployment of kelp on an oyster farm nullifies ocean acidification, thereby protecting bivalves such as oysters and clams.

Researchers said the process may also have additional ecosystem and aquaculture benefits, including sequestration and extraction of carbon and nitrogen, and protection against harmful algae blooms.

Overall, researchers said “the cultivation of kelp constitutes an environmentally friendly means of protecting shellfisheries against present and future ocean acidification and other coastal stressors.” Ocean acidification poses a major threat to shellfish, particularly in coastal zones where additional sources of acidity can further reduce pH and slow shell formation in shellfish.

While many wild populations of bivalves have collapsed, a burgeoning wave of domestic aquaculture, as well as around the world, have caused the global production of seafood via aquaculture to grow and now exceed wild capture.

“Despite this wave of aquaculture, the intensification of ocean acidification now threatens bivalve aquaculture and has necessitated a solution,” Gobler said. “We believe our work is foundational to a solution.”

The study, entitled “Kelp (Saccharina latissima) Mitigates Coastal Ocean Acidification and Increases the Growth of North Atlantic Bivalves in Lab Experiments and on an Oyster Farm,” was published in April by the trade journal Frontiers in Marine Science.

Gobler and his colleagues said their findings have strong implications for oyster farming in coastal zones.

“We have been witnessing coastal ocean acidification for years and have documented its ability to slow the growth, and even kill off, shellfish,” Gobler explained. “We began growing kelp on oyster farms to simply expand aquaculture, regionally.”

“After seeing its ability to rapidly take up CO2 and improve low pH conditions, we knew it had the potential to benefit shellfish experiencing acidification,” he added. “And while showing that in the lab was exciting, being able to improve the growth of oysters on an oyster farm experiencing coastal acidification proves this approach can have very broad applications.”