CO2 removal.
How the ocean does the heavy lifting — safely and permanently.
What it does
The alkaline stream from salt conversion is returned to the ocean. Raising local seawater alkalinity shifts the ocean's chemical equilibrium: the ocean absorbs additional atmospheric CO2 to rebalance. The CO2 is stored as dissolved bicarbonate and carbonate ions — chemically stable forms that remain in the ocean for thousands of years. The result is permanent, measurable CO2 removal, while simultaneously helping to reverse local ocean acidification.
The chemistry, in brief
Ocean acidification is caused by atmospheric CO2 dissolving into seawater and forming carbonic acid. This increases the proton (H+) concentration and lowers pH, reducing the carbonate ion availability that marine organisms — corals, shellfish, plankton — depend on.
Our process neutralises those protons by adding hydroxide ions (OH−). This does three things at once:
- It increases seawater alkalinity.
- It restores the ocean's buffering capacity.
- It shifts the carbonate equilibrium toward bicarbonate and carbonate formation.
Le Châtelier's principle predicts the rest. Removing protons drives the carbonate system to the right: dissolved CO2 is converted into bicarbonate (HCO3−) and carbonate (CO32−) ions — the stable, dissolved forms of inorganic carbon that the ocean already stores naturally and durably, on timescales of centuries to millennia.
How Henry's Law completes the cycle
Increasing seawater alkalinity also enhances how much CO2 the ocean can pull from the atmosphere. Henry's Law describes the equilibrium between atmospheric CO2 and dissolved CO2 in seawater. As hydroxide neutralises protons and dissolved CO2 converts into bicarbonate, the concentration of free dissolved CO2 in the surface ocean falls.
That creates a thermodynamic imbalance with the atmosphere above. The seawater becomes under-saturated relative to atmospheric CO2 — and additional atmospheric CO2 is absorbed across the ocean-air interface until equilibrium is re-established.
The net effect: a single mole of added alkalinity delivers both acidification reversal and atmospheric CO2 removal from the same chemistry. The two outcomes are not separate problems solved in parallel — they are two facets of the same chemical shift.
Drag the slider to add alkalinity.
Watch the potential CO2 uptake respond, the carbonate equilibrium shift on the Bjerrum plot, and the ocean start drawing additional CO2 from the atmosphere.
The same shift on the standard carbonate-speciation diagram: the marker tracks the pH set by the slider above. Raising pH moves the balance from dissolved CO2 toward bicarbonate and carbonate — which is what lets the ocean draw down more atmospheric CO2. Dissociation constants are for seawater (25 °C, salinity 35).
At baseline, dissolved CO2 is elevated, pH is depressed, and surface seawater sits close to equilibrium with the atmosphere — so little additional net CO2 is being absorbed.
Why it matters
The ocean already removes roughly a quarter of human CO2 emissions every year. Ocean alkalinity enhancement makes that natural process work harder, faster, and more measurably. Storage is genuinely permanent — bicarbonate and carbonate ions are the long-term form in which the ocean already holds inorganic carbon. The carbon ledger is verifiable through ocean chemistry. And the intervention helps the marine system rather than burdening it.
Talk to us about pilots, partnerships, or investment.
Project Alkalion, our modular demonstration, takes the technology into the real ocean environment — ahead of Ocean Ionics One, our first commercial plant.