Oceans are considered to be a big reservoir of carbon sink. Carbon dioxide can be deliberately injected into the oceans at greater depths so that the captured CO2 remains isolated from the atmosphere for centuries. Oceans absorb CO2 naturally in a slow process and try to attain a balance between the atmospheric CO2 and oceanic concentrations of CO2. But this balance has been affected due to anthropogenic carbon emissions by human activity.
The basic concept of artificial CO2 storage in ocean floor is to take a stream of CO2 captured from the power plants/industries, compress it and transport it to the deep ocean. Once injected into ocean bed, the carbon dioxide would dissolve into the surrounding sea water, disperse and become a part of the ocean carbon cycle.