Gulf of Maine experiment tests ocean alkalinity to capture CO2

Scientists conducted a controlled experiment in the Gulf of Maine, off the coast of the United States, to test ocean alkalinity enhancement as a tool against climate change. Through the LOC-NESS project, tens of thousands of liters of sodium hydroxide, commonly known as caustic soda, were released into the sea over a six-hour period in August 2025.

The goal of the experiment is to artificially increase the ocean's alkalinity, allowing it to absorb and store more carbon dioxide (CO2) from the atmosphere. While the ocean naturally regulates carbon by converting CO2 into bicarbonate and carbonate, this process leads to ocean acidification, which alters marine chemistry and harms organisms. This research seeks to determine if increasing alkalinity can boost carbon sequestration without causing further ecological damage.