I understand that bottom ocean does not equilibrate with 5000C of Earth crust because of slow mixing with colder water coming from arctic, as explained by michael sweet@11, thanks!. (skepticalscience.com)
That CO2 can reach transmission state only says it didn't equilibrate by collision. (theinconvenientskeptic.com)
Different parts of the ocean equilibrate with the atmosphere on different time scales, ranging from a year for the tropical surface ocean to a millennium for the deep sea. (realclimate.org)