[delta][sup.13]C (i) = isotopic enrichment
of tissue, at the beginning (dimensionless);
The isotopic enrichment
factor of denitrification can vary according to the denitrification rate constant and the substrate concentration (Ostrom et al.
That is, higher rates of denitrification result in higher (less negative) values of isotopic enrichment
and lower rates result in lower (more negative) values of isotopic enrichment
To overcome these difficulties in the GC/MS assessment of stable-isotope-labeled long-chain fatty acids in biological specimens, we have developed a new analytical protocol that includes the use of trimethylsilyl (TMS) esters as derivatized compounds and the calculation of isotopic enrichment
from calibration curves obtained from mixtures containing known isotopic enrichments
If we assume that [[delta].sub.species] = [[delta].sub.food ] + [delta] [plus or minus] [[sigma].sub.[delta]], where [[sigma].sub.[delta]] is the standard deviation of the values of isotopic enrichment
([delta]) in various species given in Gearing et al.
Estimates of isotopic enrichment
of biota were made during the period of maximum enrichment and are reach (0-5 kin) averages.