As the amount of carbon has risen in the atmosphere there has been a corresponding rise of carbon going into the ocean. Between 1751 and 1994 surface ocean pH is estimated to have decreased from approximately 8.25 to 8.14, representing an increase of almost 30% in "acidity" (H+ ion concentration) in the world's ocean.
The Iron Hypothesis has been proven to remove carbon dioxide from the atmosphere. It works by adding finely ground iron into the ocean which stimulates photosynthesis in phytoplanktons. The phytoplankton converts the ocean’s dissolved carbon dioxide into carbohydrate and oxygen gas. In 1993 John Martin and his associates spread a soluble solution of finely ground iron into a small patch of ocean near the Galápagos Islands in the Pacific Ocean. Their results, along with a dozen other open-sea experiments confirmed that adding iron to the ocean increases photosynthesis in phytoplankton by up to 30 times.
Issues the scientist face includes producing the finely ground iron, dispersing the iron into the sea and increasing the iron solution’s shelf-life. The amount of soluble iron dispersed into the ocean needs to be closely monitored. Algae can bloom from the excess oxygen generated by the phytoplankton and possibly suffocate the marine life below. And when the algae die, their bodies dump massive amounts of carbon dioxide into the ocean all at once, harming calcareous sponges.
Bony fishes are contributing to the alkalization of the world’s oceans. Using estimates of precipitated carbonate excretion coupled with estimates of global fish biomass, they built a model which suggested that marine fish produce approximately 3 -15% of ocean carbonate or one-quarter of the oceans increased alkalinity. This contribution is also predicted to increase as more CO2 is absorbed by the oceans. As ocean temperature and CO2 levels increase, the metabolic rates of fishes are also predicted to increase—meaning fish will play a more significant role in the offset of ocean acidification in the future.
It could be possible to genetically engineer certain bony fish and other aquatic life to boost alkanization or use aquatic management (politics and policy) to boost bony fish populations.
The carbon cycle describes the fluxes of carbon dioxide (CO2) between the oceans, terrestrial biosphere, lithosphere, and the atmosphere. Human activities such as the combustion of fossil fuels and land use changes have led to a new flux of CO2 into the atmosphere. About 45% has remained in the atmosphere; most of the rest has been taken up by the oceans, with some also taken up by terrestrial plants.
So various solutions that reduce carbon dioxide production (like shifting from coal and natural gas to nuclear) or shifting for cement production that generates a lot of carbon dioxide to alternative methods that have a net absorption of carbon dioxide.