Planktonic Marine Microbes
Teira, E., Fernandez, A., Alvarez-Salgado, X.A., Garcia-Martin, E.E., Serret, P. and Sobrino, C. 2012. Response of two marine bacterial isolates to high CO2 concentration. Marine Ecology Progress Series 453: 27-36.
In doing so, the six Spanish scientists write that "contrary to some expectations, lowering pH did not negatively affect bacterial growth." In fact, they indicate that it actually increased growth efficiency in the case of Cytophaga. And they write that "in both cases, the bacterial activity under high CO2 would increase the buffering capacity of seawater."
Teira et al.'s final words on the implications of their findings are that the responses of both marine bacterial families "would tend to increase the pH of seawater, acting as a negative feedback between elevated atmospheric CO2 concentrations and ocean acidification." And, of course, they also reveal the identities of two more sets of marine organisms that are in no way threatened by the seawater pH changes induced by the historical and still-ongoing rise in the atmosphere's CO2 concentration.