Dear Colleagues:

A graduate student here at Scripps (Aaron Hartmann) has posed the question pasted below.  If you can help him, please respond directly to him (I would be happy to be cc'd but that is not essential).  Many thanks,
Russ Chapman
P.S. Algae-L did not generate any answers to the questions on global algal biomass etc. that I posted previously, but I received many interesting replies.

Hi Russ,

I have an algae-related question to which I'm struggling to find the
answer.   I'm wondering if you wouldn't mind sending out my question
to the Algae-List (assuming that you don't know the answer!). My
problem/question is as follows:

I am trying to find a reliable signal for fertilizer runoff in marine
algal tissue.
Stable nitrogen isotopes (N15) are useful for tracking
sewage flux into coastal environments, but are not as effective for
fertilizer runoff. I realize that there are many different types of
fertilizer, which may explain the difficulty in finding a single or
group of reliable signals, but I am hopeful that such a signal exists.
I have tried to find field research studies that have used trace
metals, different forms of P, or other potential signals and have come
up empty. Has anyone found a useful signal (or group of signals) for
fertilizer runoff in algal tissue and would they be willing to share
their protocol with me?

Thank you in advance.

Aaron C. Hartmann
Graduate Student

Center for Marine Biodiversity and Conservation
Scripps Institution of Oceanography
University of California, San Diego
9500 Gilman Drive, Mail Code 0208
La Jolla, CA 92093-0208

3400 Hubbs Hall
(858) 822-1426
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Russell L. Chapman, Ph D., FLS
Executive Director, Center for Marine Biodiversity and Conservation 0202
Scripps Institution of Oceanography
University of California San Diego
9500 Gilman Drive
La Jolla, CA 92093

FAX 858-8221267