Hi all!
Re measuring the N isotopes in mussels, I think Arndt has it covered as to
the technique. I have found that drying the samples in an oven at 60C is
adequate for my samples if you don't have access to a freeze drier or have
too many samples to make this practical (as in my case). You may have to
check up on this however as I am using plant, not animal samples. Also, I
have found it easiest to dry the samples first, then grind them in an
analytical mill, which allows you to accurately control the particle size of
the sample. All of this will depend on the nature of your sample, so I
guess you will have to see which techniques are most suitable for the type
of samples you will be handling. Yoshioka and Wada's 1994 (Ecology
75(3):835-846) is also a good reference as to this type of study. They
have also written heaps more on the subject both together and separately eg
1980, 1987, 1988 (2 papers) and 1996. Van Dover et al's paper is also good -
Nature (Letters to Nature) vol. 360, March 1992. All of Bill Dennisons
work is also probably relevant. Good luck with the project!
Cheers
Jo Rush
>Randy,
>if you are just concerned about the stable isotope ratio of total nitrogen
>in the soft tissue, then it is best to first surgically remove the soft
>tissue from hard parts, if possible eliminate the gut contents (as it is
>not mussel biomass in a strict sense), thoroughly grind the tissue, then
>freeze-dry it, and ultimately use an aliquot of ca. 5 to 10 mg for
>combustion, for example in sealed quartz or Vycor tubes. By homogenizing
>the soft tissue you avoid possible fractionation that may occur between
>various organs/body parts of an organism. DeNiro and former co-workers
>have extensively used various aspects of this and similar procedures.
>Isotope geochem. textbooks mostly reference some DeNiro articles.
> Best regards, Arndt Schimmelmann
>ph 812 855 7645
>
>On Thu, 6 Nov 1997, Theodory Ronnie George wrote:
>
>> DOES ANYBODY HAVE ANY INFORMATION ABOUT THE METHODOLOGY OF MEASURING
>> NITROGEN ISOTOPE RATIOS IN THE SOFT BODY OF ZEBRA MUSSELS? DOES ANYONE
>> SUGGEST ANY REFERENCES?
>> THANKS.
>>
>
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Jo Rush Phone: 02) 9351 5118
PhD student or 02) 9351 3006
Biological Sciences A08 Fax: 02) 93351 4119
University of Sydney 2006 Mobile: 0416 28 2309
Australia Country code = 61
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