Ocean lye trial in Gulf of Maine shows potential for carbon removal, but scale and energy costs remain open questions

In August 2025, researchers released 16,500 gallons of purified sodium hydroxide into the Gulf of Maine as part of a permitted ocean alkalinity enhancement trial. Early results from Woods Hole Oceanographic Institution suggest the treated water absorbed more carbon dioxide from the air than untreated water, with no measurable effects on sampled plankton, bacteria, or larvae. The project, the first of its kind permitted by the EPA, used a pink dye tracer to track the water patch for five days. Researchers say the spread matched their models. But the trial was small and results are preliminary. Producing lye is energy intensive, so lifecycle emissions will matter if the approach ever scales. The team also notes that ocean carbon removal does not replace the need to cut emissions. For anyone following carbon markets and CDR, this trial is a useful example of how marine carbon removal projects are being tested, measured, and regulated.