Scientists in the United States released caustic soda into the ocean in an experiment that raised the sea's capacity to absorb excess carbon dioxide from the atmosphere, according to researchers at the Woods Hole Oceanographic Institution (WHOI).
The findings come from the LOC-NESS project, short for Locking Ocean Carbon in the Northeast Shelf and Slope. WHOI researchers presented the results this year at the Ocean Sciences Meeting conference in Scotland, though the test itself took place in August 2025.
The project is led by Adam Subhas of WHOI, working alongside colleagues including Kate Morkeski.
An Antacid for the Sea
The method is known as Ocean Alkalinity Enhancement, or OAE. In practice, researchers said, it works like giving the ocean an antacid.
Ocean acidity rises with pollution, which reduces the water's ability to absorb greenhouse gases. Adding alkaline substances counteracts that acidity, allowing the ocean to naturally absorb more carbon dioxide from the air.
The Gulf of Maine Test
Three ships took part in the trial, which was carried out in federal waters in the Gulf of Maine. Researchers released high-purity sodium hydroxide, the caustic soda, into the water along with a biodegradable red dye used to track its movement.
The dispersal lasted about six hours, and the team continued monitoring the site for roughly five days afterward.
Tracking the Alkaline Patch
To follow the changes in the water, the team used underwater robots and gliders that measured ocean chemistry before, during and after the sodium hydroxide was applied. Satellites and buoys tracked the alkaline patch from space and at the surface, while scientists aboard a research vessel manually collected water samples and marine organisms over the five-day period.
Results Matched Predictions
The patch behaved exactly as computer models had forecast, researchers said. The treated water returned to its normal chemical levels within the expected timeframe, and the ocean surface did absorb more carbon from the air.
David "Roo" Nicholson, one of the research leaders, said the data collected would serve as a roadmap for designing larger-scale ocean observation systems in the future.
No Harm Found to Marine Life
Biologists on the project examined organisms ranging from bacteria and phytoplankton to fish and lobster larvae. They found no negative impact on marine life in the area where the experiment was carried out.
Despite the successful results, the scientists stressed that the technology should be used to complement the fight against climate change, not to replace the urgent need to cut pollutant emissions.
