Ocean alkalinity enhancement in the Gulf of Maine captured between 2 and 10 metric tons of carbon dioxide during a four-day open-water test conducted by the Woods Hole Oceanographic Institution, according to preliminary results presented at the Ocean Sciences Meeting and reported by Chemistry World. Authorized by the U.S.
How Ocean Alkalinity Enhancement Drives Carbon Removal
Seawater acts as a chemical buffer containing dissolved carbon in three forms: carbon dioxide, bicarbonate, and carbonate, according to project documentation from the Woods Hole Oceanographic Institution. When sodium hydroxide enters the water, it shifts this chemical equilibrium. Dissolved carbon dioxide converts into bicarbonate, causing the partial pressure of carbon dioxide in the water to drop sharply. This drop forces the ocean to pull gas from the atmosphere until a new balance is reached, while simultaneously raising local pH levels against ocean acidification caused by fossil fuel emissions.
Permitting and Operational Constraints in Federal Waters
The EPA-approved trial authorized up to 50 metric tons of sodium hydroxide administered as a 50% solution in freshwater—totaling approximately 62 mil litros—within federal waters located about 61 kilometers off the coast of Cape Cod. According to reporting from the sector publication National Fisherman, the release took place over six hours across a one-square-kilometer zone limited to the upper 5 to 10 meters of the water column. Operational safety rules required operators to cut the sodium hydroxide flow rate in half mid-operation when onboard pH sensors reached authorized regulatory thresholds.
Tracing the Plume and Calculating Carbon Accounting
While laboratory calculations of theoretical capture are straightforward, tracking an open-water plume as it dilutes, spreads, and sinks presents major accounting challenges. Preliminary findings presented at the 2026 Ocean Sciences Meeting in Glasgow showed actual carbon capture ranging between 2 and 10 metric tons over four days, with models projecting total uptake to reach 50 tons over a full year.
Biological Monitoring of Bacteria, Plankton, and Larvae
Biological monitoring data released by the Woods Hole Oceanographic Institution in February 2026 compared the treated water against surrounding control zones and found no statistically significant differences across four key ecological groups. Microbial bacterial communities showed no separation from neighboring waters, photosynthetic surface phytoplanktons exhibited no detectable response, and zooplankton counts—including typical Gulf of Maine copepods—remained stable. Furthermore, young fish and lobster larvae monitored in the project area recorded no measurable impacts during the brief tracking period.
Legal Frameworks Governing Marine Alkalinization
International rules governing ocean releases trace back to the London Convention of 1972, which was promulgated in Brazil by Decree 87.566 of September 16, 1982, and is housed in the official Union decree repository. Article III of the convention defines dumping as any deliberate disposal at sea but creates a specific exception for placing materials for purposes other than mere disposal, provided the action does not contradict the convention’s goals. This legal exemption serves as the pathway for scientific marine alkalinization trials globally, requiring proposals to establish whether a material functions as waste or as a research instrument.
Frequently Asked Questions
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How much sodium hydroxide was used in the Gulf of Maine test?
The approved plan utilized up to 50 metric tons of sodium hydroxide mixed into roughly 62 mil litros of freshwater, according to Woods Hole Oceanographic Institution materials. -
What agency authorized the LOC-NESS project?
The U.S. Environmental Protection Agency issued the open-water research permit on April 23, 2025. -
Did the alkalinity test harm marine life?
Preliminary biological monitoring released in February 2026 found no statistically significant or measurable impacts on bacteria, phytoplankton, zooplankton, or fish and lobster larvae over the four-day study window.