Ocean Alkalinity

The total alkalinity of sea water is dominated by the concentration of bicarbonate ions. If you can increase the total alkalinity you can store more carbon in the upper ocean (in equilibrium with the atmosphere) at a constant pH.

Presently, the concentration of carbon dioxide in the atmosphere is rising and since the total alkalinity is almost constant the pH is falling rapidly. The Royal Society of London report [www.royalsoc.ac.uk] says that under a continuation of our current trends, the process of calcification by some phytoplankton and zooplankton will become extremely difficult, particularly in the Southern Ocean. Much human protein depends on the marine ecosystem and so we need to be to reduce the risk of large scale interruption. One approach is to increase the total alkalinity of the ocean.

The method under investigation is to use concentrated sources of carbon dioxide, such as flue gases, to dissolve calcium carbonate and form bicarbonate which is then added to the ocean. The carbon in the bicarbonate will stay in an ocean that is in CO2 equilibrium with atmosphere.

This concept not only sequesters carbon dioxide that would have invaded the ocean and lowered the pH but also leaves the ocean with a higher pH due to the increase in alkalinity.