Ocean alkalinity enhancement (OAE) is a marine carbon dioxide removal approach that increases seawater alkalinity to enhance the uptake and long-term storage of atmospheric carbon dioxide. This special issue compiles studies from the Ocean Alkalinity Enhancement Pelagic Impact Intercomparison Project (OAEPIIP), a global initiative designed to investigate the responses of natural plankton communities to OAE using a common experimental framework. Together, the contributions provide a comprehensive assessment of the biological, ecological, and biogeochemical consequences of OAE across a wide range of oceanographic regions and environmental conditions.

Review process: all papers of this special issue underwent the regular interactive peer-review process of Biogeosciences handled by members of the editorial board as well as guest editors designated by the BG co-editors-in-chief.