I would be interested, too. Maybe it would be possible to post a
summary of answers (if there were any) to the list?

Thanks
Sergine

The only question I can answer is the last one : you need
approximately 1mg for the analysis. Maybe a ittle bit less could do,
the best is to discuss this with the person in charge of the
spectrometer on which you will perform the analyses.

For the rest, I think it depends very much on the question you want
to ask. Of course diet can change the d13C, but also relative
inorganic carbon content if you compare different species (you may
acidify your samples to control for this), etc. I think there is no
simple answer to your questions about factors that may affect d13C in
zooplankton, you have to read about it and see whether the magnitude
of the variations likely to arise because of "parasite" factors are
likely to be large compared to those due to the factor you would like
to study...

Sorry not to be of more help.
Sergine

>Have you got some answer?
>I'm interested too.
>Thanks in advance
>Veronica
>-----Messaggio originale-----
>Da: Theodory R G <[log in to unmask]>
>A: [log in to unmask] <[log in to unmask]>
>Data: lunedì 30 agosto 1999 22.42
>Oggetto: D13C IN ZOOPLANKTON
>
>
> >Dear list members,
> >        I'm working with a predatory zooplankton species.  Should I expect
> >different d13C values for the same species at different sites within the
> >same lake?  Could a different diet at each location enrich or deplete the
> >d13C of the species?  Are there other factors such as depth, temperature,
> >discharges from sewage treatment plants, or d13C of DIC that could affect
> >d13C?  What would a variation in sulfur isotope composition of the species
> >in different areas tell us?
> >        My other question deals with the procedural aspects of handling
> >the zooplankton samples after collection.  Is it as simple as freezing
> >then drying the samples before analysis?  And, finally, how many
> >milligrams of the zooplankton sample would be sufficient for isotopic
> >analysis?
> >        Any help or references would be greatly appreciated.  Thank you in
> >advance.
> >
> >Cheers,
> >Ronnie
> >

Sergine PONSARD
laboratoire d'Ecologie des Populations et Communautes
UPRESA 8079
Batiment 362
Universite Paris XI
91 405 Orsay Cedex
France
Tel : 33 1 / 69 15 56 91