Hello all,

I'm fairly new to the world of stable isotopes so my question can probably be 
easily answered.  I am trying to run some of my data in IsoCon to figure out 
dietarty proportions.  However, I get some proportions that are greater than 
one and some that are negative.  Does this mean that my food sources are 
not far apart enough to discern correct proportions?  I have also read that 
some folks "correct" their consumers for isotopic fractionation.  I have not 
done this...mostly because I'm not sure what that means.  For instance, 
would you subtract ~3 from your consumer N value and ~1 from your 
consumer C value to account for the possible fractionation?  Any help would 
be greatly appreciated.  

Cheers,

Dan Nelson
MS student
University of Idaho
Department of Natural Resources