Carbon dioxide in the atmosphere enters the surface ocean by
diffusion that depends on water temperature, salinity, and
windspeed. The gas is most soluble in cold, salty water,
and greater wind speeds drive more gas into the water surface more
quickly. As a result, the upper oceans and the cold, polar
oceans will experience ocean acidification due to increased CO2
before the deep oceans. Figure 1 shows the extent to which
anthropogenic CO2 has invaded the ocean already, and the surface oceans
are clearly most affected.
Due to the large size of the ocean basin and the large capacity of
deep seawater for carbon dioxide, models predict that the ocean can
take up X amount of atmospheric CO2. However, that will come at
the cost of further decreasing ocean pH and injuring ocean ecosystems.
Ocean pH is changing throughout the worlds' oceans (figure 2) from ocean uptake of atmospheric CO2 (Kleypas et al., 2005). Even though the ocean will not become neutral or even acidic due to OA, the pH decrease due to OA can still significantly influence ocean life.