Environmental Engineering Reference
In-Depth Information
Figure 1.
15
N of the substrate
and product of a reaction with an isotope discrimination factor ()of10‰. As reaction proceeds
from right to left, the δ
Effects of isotopic fractionation. Upper panel: Trajectory of δ
15
N of the residual substrate and accumulated produce pool increase,
15
N of the product formed at any instant. Lower panel: Schematic showing the
effect of various N cycle processes on the δ
as does the δ
15
NofNO
3
−
. Trajectories for denitrification, nitrate
uptake, and sedimentary denitrification were calculated using a closed-system Rayleigh model
with isotope discrimination factors () as shown. The trajectory associated with N
2
-fixation was
calculated using a mass balance model for remineralization and nitrification of newly fixed N
with a δ
