GALWAY, IRELAND — A new study has designated farmed oysters as a “blue superfood,” capable of actively benefiting the environment by cleaning coastal waters and storing carbon. The research, focused on Irish Pacific oysters, highlights how oyster farming can tip the ecological balance toward a positive impact, rather than a burden.
Oysters Offer Net Environmental Cleanup
The study, led by the University of Galway, used a life cycle assessment (LCA) to measure the footprint of oyster farming against the ecosystem services provided by the shellfish. The key findings demonstrate the dual environmental benefits.
Oysters filter excess nitrogen and phosphorus from the water column and incorporate the nutrients into their tissues and shells. The nutrient removal measured in the study exceeded modeled nutrient pollution by 228 percent, pushing the eutrophication balance into negative territory, which signals a cleanup effect rather than a pollution burden.
One metric ton of oysters removed about 3.05 \text{ kilograms} of nitrogen and 0.35 \text{ kilograms} of phosphorus.
Oysters lock up carbon through biomineralization in their shells. About 274 \text{ kilograms} of carbon dioxide equivalent per ton of oysters ended up stored in the shell material. This storage offset roughly 73 percent of the carbon emissions generated by farm operations (such as diesel for harvesting and electricity for grading).
Economic and Dietary Potential
When scaled to Ireland’s annual oyster production, the sector could remove an estimated 33.9 tons of nitrogen and 3.9 tons of phosphorus annually, while storing about 834.3 \text{ tons} of carbon in shells.
Researchers estimated the nutrient clean-up service to be valued at approximately $2.13 million per year, based on the cost utilities would otherwise incur to achieve the same water quality improvements.
The study confirms that unfed shellfish are among the aquatic foods with the lowest emissions. On a protein basis, the oyster’s footprint, including the shell’s carbon storage, was 5.7 \text{ kilograms} of carbon dioxide equivalent per kilogram of oyster protein. The authors emphasize that oysters are a sustainable food source that offers both high nutrient density and local environmental benefits.