Harnessing nature's buffer: Assessing the role of bivalve shells in coastal alkalinity regeneration

Abstract Bivalve shells, a natural alkaline material, play a crucial role in coastal carbon cycles by influencing total alkalinity (TA) and dissolved inorganic carbon (DIC). This study investigated oyster shell dissolution in Narragansett Bay, Rhode Island, under varying p CO 2 conditions, revealing TA regeneration rates of 4–56 μ mol L −1 d −1 , which could mitigate localized ocean acidification (OA). Notably, significant dissolution occurred even in oversaturated waters (Ω calcite > 1) due to corrosive microenvironments created by microbial respiration. Although shell formation (calcification) emits CO 2 , TA regeneration (shell dissolution) buffers OA when the carbonate chemistry of the water is corrosive, offsetting the initial CO 2 emissions. Therefore, recycling shells enhances ecosystem resilience by buffering acidification stress for OA‐sensitive organisms. This research highlights the need to revisit shell management policies to promote sustainable aquaculture and sheds light on the potential of incorporating this nature‐based alkaline material into ocean alkalinity enhancement strategies for improved coastal carbon management.