Researchers Tested Ocean Carbon Removal in Gulf of Maine

A 2025 trial released 16,500 gallons of sodium hydroxide to study carbon dioxide absorption in seawater.

Updated on Sept. 29, 2026 in Environmental

A research vessel on open ocean water with a fluid-dispersal nozzle creating foam and floating scientific sensor buoys nearby. — Researchers in the Gulf of Maine conducted an EPA-permitted trial, dispersing 16,500 gallons of sodium hydroxide to test seawater's ability to absorb atmospheric carbon dioxide. AI Illustration. Upload story photo >

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In August 2025, researchers conducted the first EPA-permitted trial involving the release of 16,500 gallons of sodium hydroxide into the Wilkinson Basin of the Gulf of Maine. The experiment tested whether increasing seawater alkalinity could enhance carbon dioxide absorption.

Why it matters

Scientists are exploring ocean alkalinity enhancement as a method to mitigate rising atmospheric carbon dioxide levels. The goal is to capture more carbon without significantly altering the acidity or health of the surrounding marine ecosystem.

The five-day monitoring period utilized robotic gliders, satellites, and underwater vehicles to track the Rhodamine Water Tracer patch. Researchers observed no significant differences in biological health among fish, lobster larvae, or plankton within the treated area.

The players

Environmental Protection Agency

This federal agency is responsible for regulating human health and environmental impact through permitting and scientific oversight.

The details

During the six-hour release, a ship dispersed highly purified sodium hydroxide into the Wilkinson Basin. The team monitored a wide array of marine life to ensure the substance did not negatively impact the local biological environment.

April 2025: The Environmental Protection Agency approved the research project.
August 2025: Researchers released sodium hydroxide into the Gulf of Maine.
February 2026: The team announced preliminary results and ongoing analysis.

The Big Picture

This project represents a critical shift toward field-based testing for ocean-based carbon removal technologies. It marks a departure from theoretical modeling by providing empirical data on how alkaline substances interact with complex, open-water ecosystems.

While this study focuses on large-scale carbon capture, the findings help determine if ocean alkalinity enhancement is a safe, viable tool for future climate policy. Successful implementation could eventually lead to new, non-invasive methods for lowering atmospheric carbon levels.

The takeaway

Ocean alkalinity enhancement is currently in the early stages of experimental validation to verify its safety and efficacy. Researchers continue to analyze findings from the Gulf of Maine to assess the feasibility of scaling this technology for climate mitigation.