Ecoinformatics Problems of the World Ocean - New Ecoinformatics Tools in Environmental Science: Applications and Decision-making - page 270

In conclusion, the arctic waters play the role of a pump that pumps away carbon
dioxide from the atmosphere. Therefore, a detailed study of this process is needed
to specify the global model of carbon cycle and to raise the accuracy of the esti-
mation of the greenhouse effect due to emissions of anthropogenic CO 2 .
On the whole, in the synthesis of the global model of the CO 2 biogeochemical
cycle, the unit that simulates the ocean part of this cycle must describe the func-
tioning of the ocean carbonate system. Alexeev et al. (1992), analyzed the system
CO 2 -HCO 3 -CO 2 − and the distribution of pH values of the ocean waters and found
out that more than 80 % of dissolved carbon dioxide are in the form of hydro-
carbonate ion of HCO 3 . This means that only a

first stage of dissociation of car-
bonic acid can be reliably considered in the synthesis of the model of the ocean
carbonate system.
On global scales, in the World Ocean regions with cold waters (northern lati-
tudes, upwelling zones) the

ux H 2 .
The dynamics of this regime is maintained by reactions that take place in the
hydrosphere between CO 2 and water resulting in the formation of carbonic acid:

fl ux H 3 prevails while in the warm waters the fl

H 2 CO 3 þ OH CO 2

3

H 2 CO 3 þ 2OH ;

HCO 3 þ H 2 O , ; þ 2H 2 O ,

In the salt water, there are dissolved carbon dioxide, non-dissociated molecules
of H 2 CO 3 , anions of HCO 3 , and CO 3 2 − . They all are in equilibrium:

CO 2 þ H 2 O , H 2 CO 3 , HCO 3 þ H þ , CO 2

þ 2H þ

3

An equilibrium state between carbonic acid bicarbonate and carbonate ions
establishes rapidly. The solution of CO 2 and formation of H 2 CO 3 take place much
slower. However, since many authors dispute the availability of H 2 CO 3 , the sum-
marized concentration of CO 2 and H 2 CO 3 should be considered, denoting it as
[CO 2 ]. Let us introduce notations to characterize the total concentration of inter-
mediate components
X C ¼ CO 2

þ CO 2
3

þ HCO 3

½ þ H 2 CO 3 ½ ð 4 : 1 Þ

Another characteristic of the hydrosphere is alkalinity:

þ 2 CO 2 3 þ H 2 CO 3

A= HCO 3 OH H þ ½ ½ ½ 4 : 2 Þ

where [Ca 2+ ] and [H + ] are the concentrations of ions of calcium and hydrogen
respectively, and HCO 3 and [CO 2 − ] are the concentrations of bicarbonate and
carbonate ions correspondingly.