Olivine for Ocean Carbon Dioxide Removal: NOAA and Canadian Scientists Test Effects on Phytoplankton

NOAA Fisheries and Fisheries and Oceans Canada researchers ran a small marine carbon dioxide removal experiment at the Milford Lab in Connecticut. They added the mineral olivine to seawater inside 12 mesocosms built from off-the-shelf home brewing fermenters. Olivine raised alkalinity and pH, and the treated bottles grew more phytoplankton than the controls. The surprise was that the growth response was not driven by the metals people usually focus on. Instead, olivine contributed nitrogen, a nutrient that can fuel blooms. The results are useful for ocean alkalinity enhancement, but they come with a warning. Too much nitrogen from olivine could trigger phytoplankton blooms that decompose, consume oxygen, and lower pH, which would undercut the intended benefit. The study was short-term, and the authors say additions would need to be small. More research is needed on nitrogen release rates, long-term effects, and real coastal conditions before marine CDR protocols can treat olivine as a safe, measurable removal method.