229
Dissolved Gases Other than CO 2
At temperature t = 25°C and humidity (h) = 100%, the vapor pressure of water is 3.169 kPa
or 0.03169 bar. Thus, the water will contribute 3% to the total pressure (similar to Ar). The
partial pressure of the other gases can be converted to dry air using
P P
h
P
X
i
T
H O
i
=
−
[
(
)
]
/100 2
(6.7)
The stable isotopic composition of atmospheric gases is summarized in Table 6.2 (Kester,
1975). The values of the mole percentage were calculated using 5 × 10 21 g or 1.71 × 10 20 moles
for the total atmosphere.
6.3 Dissolution of Gases in Seawater
The concentration of a gas in solution is related to the partial pressure by Henry’s law:
P i = k i [i]
(6.8)
where [i] is the concentration of the dissolved gas (expressed in mol kg –1 of solution), and k i is
the Henry’s law constant. The parameter k i will depend on the particular gas, the salinity or
ionic strength of the solution, the temperature, and total pressure. Equilibrium is obtained
when the partial pressure of the gas in solution is equal to the value in the gas phase:
P i (soln) = P i (gas)
(6.9)
Table 6.2
Isotopic Abundance of Atmospheric Gases
Element
Mass Number
Mole%
Element
Mass Number
Mole%
H (in H 2 O)
1
99.98
Kr
78
0.354
H (in H 2 O)
2
0.02
Kr
80
2.27
He
3
1.1 × 10 –4
Kr
82
11.56
He
4
100.0
Kr
83
11.55
C (in CO 2 )
12
98.9
Kr
84
56.90
C (in CO 2 )
13
1.1
Kr
86
17.37
C (in CO 2 )
14
9.5 × 10 –13
N
14
99.62
Xe
124
0.096
N
15
0.38
Xe
126
0.090
O
16
99.757
Xe
128
1.919
O
17
0.039
Xe
129
26.44
O
18
0.204
Xe
130
4.08
Ne
20
90.92
Xe
131
21.18
Ne
21
0.257
Xe
132
26.89
Ne
22
8.82
Xe
134
10.44
Ar
36
0.337
Xe
136
8.87
Ar
38
0.063
Ar
40
99.600
Source: Data from Kester, D.R., Dissolved gases other than CO 2 , in Chemical
Oceanography, Vol. 1, 2nd ed., J.P. Riley and G. Skirrow, Eds., Academic
Press, New York, 498–556, 1975.
Dissolved Gases Other than CO 2
At temperature t = 25°C and humidity (h) = 100%, the vapor pressure of water is 3.169 kPa
or 0.03169 bar. Thus, the water will contribute 3% to the total pressure (similar to Ar). The
partial pressure of the other gases can be converted to dry air using
P P
h
P
X
i
T
H O
i
=
−
[
(
)
]
/100 2
(6.7)
The stable isotopic composition of atmospheric gases is summarized in Table 6.2 (Kester,
1975). The values of the mole percentage were calculated using 5 × 10 21 g or 1.71 × 10 20 moles
for the total atmosphere.
6.3 Dissolution of Gases in Seawater
The concentration of a gas in solution is related to the partial pressure by Henry’s law:
P i = k i [i]
(6.8)
where [i] is the concentration of the dissolved gas (expressed in mol kg –1 of solution), and k i is
the Henry’s law constant. The parameter k i will depend on the particular gas, the salinity or
ionic strength of the solution, the temperature, and total pressure. Equilibrium is obtained
when the partial pressure of the gas in solution is equal to the value in the gas phase:
P i (soln) = P i (gas)
(6.9)
Table 6.2
Isotopic Abundance of Atmospheric Gases
Element
Mass Number
Mole%
Element
Mass Number
Mole%
H (in H 2 O)
1
99.98
Kr
78
0.354
H (in H 2 O)
2
0.02
Kr
80
2.27
He
3
1.1 × 10 –4
Kr
82
11.56
He
4
100.0
Kr
83
11.55
C (in CO 2 )
12
98.9
Kr
84
56.90
C (in CO 2 )
13
1.1
Kr
86
17.37
C (in CO 2 )
14
9.5 × 10 –13
N
14
99.62
Xe
124
0.096
N
15
0.38
Xe
126
0.090
O
16
99.757
Xe
128
1.919
O
17
0.039
Xe
129
26.44
O
18
0.204
Xe
130
4.08
Ne
20
90.92
Xe
131
21.18
Ne
21
0.257
Xe
132
26.89
Ne
22
8.82
Xe
134
10.44
Ar
36
0.337
Xe
136
8.87
Ar
38
0.063
Ar
40
99.600
Source: Data from Kester, D.R., Dissolved gases other than CO 2 , in Chemical
Oceanography, Vol. 1, 2nd ed., J.P. Riley and G. Skirrow, Eds., Academic
Press, New York, 498–556, 1975.