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Chemical Oceanography, 4th Edition
C = –2.892532 + 116.270079/T + 0.45788501 ln T
D = –0.00613142
where the thermodynamic value is given by
ln K HB = 148.0248 – 8966.90/T – 24.4344 ln T
(7.70)
The effect of pressure on K HB * can be determined from Equation 7.62, where
–ΔV HB = 29.48 – 0.295(S – 34.8) – 0.1622(T − 273.15)
(7.71)
–103ΔK HB = 2.84 – 0.354(S – 34.8)
(7.72)
The solubility of CaCO 3 in its two major forms, calcite and aragonite, is also needed
when studying the carbonate system. The stoichiometric solubility product is given by
K SP * = [Ca 2+ ][CO 3
2– ]
(7.73)
and is related to the thermodynamic value by
K SP * = K SP /­ γ T (Ca 2+ )γ T (CO 3
2– )
(7.74)
The values in seawater are given by (Mucci, 1983)
ln K SP * = ln K SP (i) + A S 0.5 + B S + C S 1.5
(7.75)
where
A cal = –0.77712 + 0.0028426 T + 178.34/T
B cal = –0.07711
C cal = 0.0041249
A arag = –0.068393 + 0.0017276 T + 88.135/T
B arag = –0.10018
C arag = 0.0059415
The thermodynamic Ksp is given by
ln Ksp(calcite) = –171.9065 – 0.077993 T + 2839.319/T + 71.595 log T
(7.76)
ln Ksp(aragonite) = –171.945 – 0.077993 T + 2903.293/T + 71.595 log T
(7.77)
The effects of pressure on the solubility of calcite and aragonite are calculated from
Equation 7.65, where