In the ocean that surrounds Antarctica, deep water wells up to the surface, carrying nutrients and other dissolved materials needed by light-loving ocean life. One of these materials is calcium carbonate, which, when dissolved, raises seawater alkalinity and helps the ocean respond to increasing carbon dioxide levels. Ocean currents carry this alkalinity-enriched water northward—unless tiny organisms intercept it and trap the alkalinity in the Southern Ocean.
source https://phys.org/news/2021-02-tiny-microorganisms-southern-ocean-affect.html
