The Carbon Cycle - Introduction to Carbon Capture and Sequestration - page 114

CO 2 rivers: weathering

of rocks

CO 2 + H 2 O HCO 3 - + H + 2H + + CO 3 2-

CaCO 3

corals, benthic algae ,
coccolithophorids and
planktonic foraminifera.

C org

CO 2 + H 2 O HCO 3 - + H + 2H + + CO 3 2-

CaCO 3

C org

Figure 3.3.2 CO 2 chemistry in the ocean
This animation can be viewed at : http://www.worldscientifi c.com/worldscibooks/
10.1142/p911#t=suppl

For many years these chemical equilibria have been in a steady state
situation, where the fl ux of CO 2 leaving the ocean surface equals the fl ux
entering the ocean surface. Furthermore, the ocean's burial rate of
CaCO 3 equals the amount of CaCO 3 entering through the rivers.

Flow in the oceans

In the previous section, we discussed the CO 2 chemistry of the oceans.
To fully understand the mechanism it is important to comprehend ocean
fl ow patterns. These patterns are shown schematically in Figure 3.3.3
and Movie 3.3.1. We see that water fl ows in a circular pattern: both in the
Atlantic Ocean and in the Southern Ocean. In the deep ocean, regener-
ated CO 2 and regenerated nutrients follow the same pattern. An impor-
tant difference between the two regions is that in the Northern Atlantic
most of the surface is at a high latitude while in the Southern Ocean most
of the surface is at low latitudes. In the vast low-latitude oceans of the
Atlantic, the nutrients are almost completely consumed and returned to
the ocean interior as sinking organic matter. However, in the warm and