That is only true for sea water near surface. I am talking about deeper levels of the ocean. If my calculation is correct the mass of CO2 released into the air

That is only true for sea water near surface. I am talking about deeper levels of the ocean. If my calculation is correct the mass of CO2 released into the air per year is roughtly 1/35000 the mass of all sea water in the oceans. Sounds not too concentrated to me.