Dear Bill
This one may be useful

Huang, Y., Eglinton, G., Ineson, P., Latter, P.M., Bol, R., Harkness, D.D.
(1997) Absence of carbon isotope fractionation of individual n-alkanes in a
23-year field decomposition experiment with Calluna vulgaris. Org. Geochem.,
26(7/8):497-501. 

Rafael
>Hello all, 
>
>I'm looking into using the isotope (d13C and d18O) values of Amazonian
rainforest litter (as well as fruits and seeds) as a means of tracking
animal life history. Has anyone out there compared d13C(organic) and
d18O(organic) values of wood decay products with the original
d13C(cellulose) and d18O(cellulose) values? Additionally, I'm interested in
any isotope analyses of carbohydrates, fats, and proteins in low-latitude
fruits (including seeds). Any references (or insight?) would be most welcome!
>
>Cheers,
>Bill
>
> NOTE: Email address from 12/24/97 through 1/5/98 will be "Wppatter
<[log in to unmask]>" 
>
>William P. Patterson
>Syracuse University 
>Department of Earth Sciences
>Syracuse, NY 13244-1070
>Phone: 315-443-3869
>http://128.230.24.91/Bill/Patterson.html
>Mórán cainte ar bheagán cúise
Rafael Nunez Gomez
Laboratorio Isotopos Estables
Estacion Experimental del Zaidin (C.S.I.C.)
Profesor Albareda 1, 18008
Granada, Spain
Tf 34 58 121011
Fax 34 58 129600
[log in to unmask]
http://www.eez.csic.es/~isotopos/