A research team released 16,500 gallons of sodium hydroxide solution into the Gulf of Maine in August 2025 to test whether raising seawater alkalinity could pull more carbon dioxide from the air. The trial, the first ocean alkalinity enhancement experiment permitted by the EPA in U.S. federal waters, drew an estimated 2 to 10 metric tons of CO2 during the monitoring period, with models projecting up to 50 tons over a year. No significant effects on plankton, fish larvae, or lobster larvae were reported in preliminary results presented in early 2026. The project changed its design after commercial fishing groups raised concerns about potential harm to marine life and food safety. The team dropped a planned site south of Martha's Vineyard and ran a single trial in the Gulf of Maine instead. The permitting process included two public comment periods and more than 250 comments. The main open questions are the lifecycle emissions from producing purified sodium hydroxide and whether the carbon stays stored for long enough to matter for climate accounting.
