Environmental Engineering Reference
In-Depth Information
Mariager Fjord [38]. Unfortunately, we do not have high quality nutrient data
from before the earthquake to determine whether ratios were the same as those
observed by [37].
Figure 8.
For data collected on January 2004, the relationship between nutrient species and
sulfide. Open symbols are from depths between the suboxic zone and 400 m.
Finally, a plot of alkalinity vs. TCO
2
(Fig. 9) can provide information on
the type of metabolic processes responsible for organic carbon mineralization.
If the dominant process were sulfate reduction coupled with organic matter
remineralization, as predicted by Zhang and Millero [37], the slope of a plot
of alkalinity versus TCO
2
should be 1. In fact, the observed slope is 0.76
(r
2
= 0.976). Sulfide oxidation, producing elemental sulfur, thiosulfate and/or
sulfite, will decrease alkalinity without affecting TCO
2
, so the fact that our
observed slope is less than one is consistent with our hypothesis that sulfide
oxidation is an important sink for sulfide in the Cariaco. It also is consistent with
our observations of fluctuation in the depth of the oxycline, with the phosphate
