Being unable to work at any speed in the lab and being liable to dropping things due to my dodgy shoulder, I have taken the opportunity to catch up on some website pages.  The species profiles are finally undergoing some work - the page for Hermann's is now up (link) and I'm getting to work on Horsfields.

I ran a plate of claw samples this week and so far it would seem that claw is more enriched in both carbon and nitrogen than the shell (by about 1.5 permil for carbon, and by about 2 or 3 permil for nitrogen).  I can't say much more than that at the moment as I used whole claw and do not know what time period it reflects.  The enrichment could be due to different trophic enrichment factors (TEFs) (tissues formed using the same foodsource may end up with different isotope ratios to each other due to different metabolic pathways), may reflect a change in location or diet between when the shell was grown and when the claws were grown, or be a combination of these factors.  

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