Groundbreaking Ocean Experiment Tests Carbon Capture Potential
In a bold scientific endeavour last August, research vessels participating in the Loc-ness project released 65,000 litres of sodium hydroxide into the Gulf of Maine. This environmental research trial of ocean alkalinity enhancement (OAE) was designed to investigate whether deliberately altering ocean chemistry could help mitigate global heating and ocean acidification.
The Science Behind Ocean Alkalinity Enhancement
Ocean alkalinity enhancement mimics natural weathering processes but operates on human timescales rather than geological ones. The ocean already contains approximately 38,000 billion tonnes of carbon stored as dissolved bicarbonate, according to Adam Subhas, lead oceanographer of the research team. By boosting this natural alkalinity with chemical antacids, scientists theorize the ocean can absorb additional carbon dioxide from the atmosphere.
The experiment, licensed by the US Environmental Protection Agency and overseen by Woods Hole Oceanographic Institution scientists, took place 50 miles off the Massachusetts coast in waters commonly fished for cod, haddock, and lobster. Despite initial appearances resembling a toxic red tide due to the red dye used to track the chemical, the trial yielded promising preliminary results.
Measurable Environmental Impact
Over five days of intensive monitoring using autonomous gliders, underwater vehicles, and shipboard sensors, researchers documented significant changes:
- Approximately 10 tonnes of carbon entered the ocean during the observation period
- Local pH levels increased from 7.95 to 8.3, representing a return to preindustrial alkalinity levels
- No significant harm was detected to plankton, fish larvae, or lobster larvae
The study has not yet undergone peer review, but early findings presented at the AGU Ocean Sciences Meeting in Glasgow suggest OAE could potentially prevent global temperatures from exceeding 2°C above preindustrial levels when combined with sharp emissions reductions.
Environmental Concerns and Ethical Considerations
Not everyone views this technological approach positively. Benjamin Day, a senior campaigner at Friends of the Earth US, expressed profound concern about "catastrophic unforeseen consequences" if OAE were implemented at scale. He warned against what he sees as a dangerous push to exert precise control over natural systems.
However, Phil Renforth, a carbon dioxide removal expert at Heriot-Watt University, argues that humanity is already conducting uncontrolled climate experiments through carbon emissions. "We really need to think about this in terms of stewardship," Renforth emphasizes, questioning whether we can proactively manage how carbon enters oceans rather than simply allowing it to happen passively.
Historical Precedents and Commercial Applications
The concept of alkalinity enhancement has historical roots dating back 2,000 years to Greek farmers who used lime to neutralize acidic fields. More recently, Scandinavian rivers suffering from acid rain were treated with alkaline lime in the 1980s, successfully restoring native salmon populations to Sweden's Ätran River.
Today, numerous OAE startups have been verified to sell carbon credits through the international carbon removal registry Isometric. These credits are purchased by companies aiming to achieve net-zero status for their businesses. The US National Oceanic and Atmospheric Administration estimates OAE could potentially remove between 1 billion and 15 billion tonnes of CO2 annually at costs up to $160 per tonne.
Community Engagement and Future Research
Sarah Schumann, a commercial fisher who served as an observer during the experiment, noted that researchers conducted 50 meetings with fishers, tribal leaders, and stakeholders along the Massachusetts coastline before proceeding with the field trial. While local fishers generally trust the science, Schumann expressed concern that this research could become a "Trojan horse" allowing commercial operators to advance technologies primarily for carbon credit eligibility rather than environmental benefit.
The research team, which includes scientists from Woods Hole Oceanographic Institution, Rutgers University, and the Environmental Defence Fund, plans to continue modeling how the chemical plume absorbs CO2 over time. In their best-case scenario, the dispersal could lead to approximately 50 tonnes of carbon dioxide uptake from the atmosphere into seawater over one year—equivalent to the annual emissions of five UK citizens.
Despite the modest scale of this initial experiment, researchers emphasize they began small to establish best practices in a rapidly evolving field. As Renforth concludes, "There are not many places on our planet where we can store carbon. We shouldn't be throwing anything off the table until we've really got a workable solution across the whole space."
