Benthic and tropopause are the the two main sources of temperature difference with the ocean surface, for proposed carnot cycles that generate electricity in the tropical oceans. These cycles necessarily create large fluid flows near the ocean surface which pass next to the site where electricity is being generated.
Utilizing that electricity to remove CO2 from those fluid flows makes virtue of necessity.
I understand there are quite a number of techniques proposed for such oceanic carnot-cycles, but the aforementioned "virtue of necessity" applies to all of them. Therefore, I would suggest that these ocean thermal electrical generation proposals are inherently suited to carbon dioxide removal.
*I was instrumental in helping Michaud get his grant from Thiel, and remain unconvinced by Bonnelle's critique regarding Rayleigh Instability -- so I do have a dog but I won't unleash him in this particular fight. Let's not quibble when we can agree on more fundamentally important issues. (And by the way, I brought up "tropopause" rather than "upper trophosphere" precisely because I am aware of the danger of overshoot delivering water vapor to the stratosphere. So don't jump all over that either.)