108
Fig. 4.16. Profiles of pH, TeOz,
and TA in the Framvaren Fjord
(Yao and Millero 1995b)
§
• Q. Qj
Q
20
40
60
80
100
120
140
160
180
200
0
4
6.8
7.0
0
4
F.J. Millero
TC0 2 (mM)
8
12
16
20
24
pH
7.2
7.4
7.6
7.8
8.0
8
12
19
20
TA(mM)
the impact of fresh water is minor. The cause of the higher values of NTC02 in the surface waters may be due to the oxidation of organic matter in oxic water or diffusion
from below the interface.
Plots of ~TA and ~TC02 vs. H2S are shown in Fig. 4.17. The linear correlation between these properties demonstrates that hydrogen sulfide is produced proportionatelytothe formation of both TC02 and TA.However, the values of ~TA / ~H2S = 3.42 ±0.1
and ~TC02/ ~H2S = 3.00 ±0.12 are both higher than the model values. Based on previous data, a value of ~TC02/ ~H2S = 2.54 was obtained by Dyrssen (1988). The ratio
of ~ TA to ~ TC02 in anoxic waters of the Framvaren is 1.14 and equal to the model value.
Dyrssen (1988) found a similar value of ~TA/ ~TC02 (1.15). The differences between
the observed ratios and the model values may be attributed to a combination of the
high values of TA and TC02 and the low values ofH 2 S. The low H 2 S concentration could
be due the formation of Fe sulfides
2 FeOOH + 3 H2S ~ FeS + FeS2 + 4 H20
without changing TA and TC02. The inflow of O2 containing water through the sill may
cause the removal of H2S in the deep waters of the Framvaren, such as the renewal of
the bottom waters when the channel was dug in 1850. In order to keep the same devia-