0
100
200
300
400
500
600
0
1 0
2 0
3 0
0
5000
10000
15000
20000
25000
0
500
1000
1500
2000
2500
1300
1500
1700
1 900
2 100
0
500
1000
1500
2000
2500
3000
0
1 0
2 0
3 0
(a)
(b)
(c)
Water / atmospheric pCO
2
(µatm)
Water / air temperature (°C)
Water
Atmosphere
Water pCO
2 for TA
(µatm)
Water pCO
2 for DIC
(µatm)
TA / DIC (µmol kg
−1
-water)
TA
DIC
Salinity
Water pCO
2
(µatm)
Fig. 6.3 Physical and chemical parameters used to determine CO 2 partial pressure (pCO 2 ) in
water. (a) Changes in pCO 2 due to changes in water or atmospheric temperature assuming that CO 2
concentration is constant. Computational conditions: water temperature, variable; TA,
2200 μmol kg
−1 -water; DIC, 1950 μmol kg
−1 -water; salinity, 35; air temperature, variable; atmospheric CO 2 concentration, 15.85 mmol m
−3 ; atmospheric pressure, 1 atm. (b) Change in pCO 2 in
water due to changes in total alkalinity (TA) and dissolved inorganic carbon concentration (DIC).
Computational conditions: DIC, variable; TA, 2200 μmol kg
−1
-water; water temperature, 20 °C;
salinity, 35; TA, variable; DIC, 1950 μmol kg
−1 -water; water temperature, 20 °C; salinity, 35. (c)
Changes in pCO 2 in water due to changes in salinity assuming that TA and DIC also change
because of salinity. Computational conditions: water temperature, 20 °C; river end member: salinity, 0; TA, 800 μmol kg
−1 -water; DIC, 850 μmol kg
−1 -water; marine end member: salinity, 35; TA,
2200 μmol kg
−1 -water; DIC, 1950 μmol kg
−1 -water