Alayne:

It is possibl;e that Mike Talbot may have run carbon isotopes on some of my
Botryococcuu-Pediastrum gyttja from Mahoma Lake.  Judging from the amount of
effervescence there was on that lake in July of 1960, I'd say that there is
a good possibility of heavy methanogenesis (the deep water was quite anoxic)
and recycling of heavy carbon through photosynthesis.  Drop Mike a note at
Bergen.  I have an address for him, but it doesn't evoke e-mail replies and
I suspect that it is faulty.

All the best

Dan

  >Hi everybody!
>
>Can anyone provide me with examples of very heavy delta-13C values in 
>organic matter from modern environments (higher than -10 in TOC)?
> 
>We have been studying Late Quaternary lake sediments from high-
>altitude lakes on various East African mountains. In our cores we 
>have found delta-13C values as high as -7 per mille in TOC and -5 per 
>mille in individual algal lipids.  These occur at more than one site, 
>and at two sites are associated with remains of green algae 
>(Botryococcus and Pediastrum).
>
>We are in the process of setting up a modest stable-isotope lab here 
>in association with the existing Radiocarbon Laboratory.  More 
>anon.
>
>Alayne
>
>F.A. Street-Perrott
>Research Professor of Physical Geography
>Tropical Palaeoenvironments Research Group
>Department of Geography
>University of Wales Swansea
>Singleton Park
>Swansea SA2 8PP
>Tel +44-1792-295910
>Fax +44-1792-205556
>e-mail  [log in to unmask]
>
>
>