282
Chemical Oceanography, 4th Edition
1. Removal by photosynthesis
2. Removal by dissolution of CaCO 3
3. Removal by solar heating
4. Addition by oxidation of plant material
5. Addition by formation of CaCO 3
6. Addition by increases in CO 2 in the atmosphere from fossil fuel burning
Unraveling all these effects is even more difficult because of the sluggish response of the
oceans to changes in the level of CO 2 in the atmosphere. As with other gases, the driving
force of CO 2 across the air–sea interface is the differences between the concentrations in
the atmosphere and oceans given by
Flux = k{pCO 2 (SW) – pCO 2 (ATM)} = k ΔpCO 2
(7.122)
where the value k is called the transfer velocity. Liss (1975) divided this transfer velocity
into two terms:
1/k = 1/αk W + 1/Hk A
(7.123)
where k w and k A are transfer velocities in the water and air, respectively; H is the Henry’s
law constant (a unitless value, the ratio of air to water concentrations at equilibrium); and
α is a factor that accounts for any enhancement of the transfer on the water side caused
by chemical reactions between the gas and H 2 O (CO 2 + H 2 O → H + + HCO 3
– ). The value
of α is 1.02 to 1.03 for CO 2 . From 14 C measurements, values of k w average about 6 mol m –2
yr –1 μatm –1 on a global basis. The transfer velocity increases with increasing wind speed
(see Figure 7.12). The values of k determined in wind tunnel measurements are 3 to 4 mol
m –2 yr –1 μatm –1 , much smaller than the value estimated from 14 C measurements, making it
Year
pCO
2 (µatm)
260
280
300
320
340
Atmospheric CO 2
TTO/NA
GEOSECS
IGY
1.5 ± 0.5 µatm yr
–1
Oceanic CO 2
1960
1965
1970
1975
1980
Figure 7.11
A comparison of the increase of the partial pressure of carbon dioxide in the atmosphere and the ocean from
1957 to 1980.
Chemical Oceanography, 4th Edition
1. Removal by photosynthesis
2. Removal by dissolution of CaCO 3
3. Removal by solar heating
4. Addition by oxidation of plant material
5. Addition by formation of CaCO 3
6. Addition by increases in CO 2 in the atmosphere from fossil fuel burning
Unraveling all these effects is even more difficult because of the sluggish response of the
oceans to changes in the level of CO 2 in the atmosphere. As with other gases, the driving
force of CO 2 across the air–sea interface is the differences between the concentrations in
the atmosphere and oceans given by
Flux = k{pCO 2 (SW) – pCO 2 (ATM)} = k ΔpCO 2
(7.122)
where the value k is called the transfer velocity. Liss (1975) divided this transfer velocity
into two terms:
1/k = 1/αk W + 1/Hk A
(7.123)
where k w and k A are transfer velocities in the water and air, respectively; H is the Henry’s
law constant (a unitless value, the ratio of air to water concentrations at equilibrium); and
α is a factor that accounts for any enhancement of the transfer on the water side caused
by chemical reactions between the gas and H 2 O (CO 2 + H 2 O → H + + HCO 3
– ). The value
of α is 1.02 to 1.03 for CO 2 . From 14 C measurements, values of k w average about 6 mol m –2
yr –1 μatm –1 on a global basis. The transfer velocity increases with increasing wind speed
(see Figure 7.12). The values of k determined in wind tunnel measurements are 3 to 4 mol
m –2 yr –1 μatm –1 , much smaller than the value estimated from 14 C measurements, making it
Year
pCO
2 (µatm)
260
280
300
320
340
Atmospheric CO 2
TTO/NA
GEOSECS
IGY
1.5 ± 0.5 µatm yr
–1
Oceanic CO 2
1960
1965
1970
1975
1980
Figure 7.11
A comparison of the increase of the partial pressure of carbon dioxide in the atmosphere and the ocean from
1957 to 1980.