Look, I know that bubbling CO
2 in a closed water system, say a fish tank, will form some amount of carbonic acid and lower the pH, but only to the extent of free hydrogen ions already present. To increase acidity in a macro NON-closed system, one simply must keep introducing or creating
new hydrogen ions. Further, carbonic acid in water breaks down over time under heat (I doubt there's much carbonic acid in the GOM right now...heh heh).
Where does the new hydrogen come from?