Re: NANFA-- salmon carcass nutrients article

Jay DeLong (
Sat, 27 Jan 2001 10:41:47 -0800


>Various metabolic processes in some organisms "discriminate" against N15,
>because each atom weighs slightly more than an atom of N14; more work to
>move the N15 around. So, as a result of this continuous discrimination,
>some organic residues will be "lighter"; they'll contain relatively more
>N14. On the other hand, other metabolic processes in other organisms don't
>discriminate against N15, so that they'll contain relatively more N15 and
>be considered "heavy" or enriched in N15. The isotopic ratio can be
>considered a signature, and gives you important clues to both the origin
>of organic material and an idea of how trophic webs work (who eats who).

Thanks! I wonder at what trophic level(s) this is most important. Using
the salmon example, are marine salmon metabolic systems less discriminatory
because these fish have to grow large fast? Or is it because that
discrimination occurred with their food, or their food's food? Or none or
all, or is it not that simple?

Jay DeLong
Olympia, WA

/----------------------------------------------------------------------------- /"Unless stated otherwise, comments made on this list do not necessarily / reflect the beliefs or goals of the North American Native Fishes / Association" / This is the discussion list of the North American Native Fishes Association / To subscribe, unsubscribe, or get help, send the word / subscribe, unsubscribe, or help in the body (not subject) of an email to / For a digest version, send the command to / instead. / For more information about NANFA, visit our web page, </x-flowed>