Science, Vol 236, Issue 4797, 66-68
Copyright © 1987 by American Association for the Advancement of Science
Natural abundances of carbon isotopes in acetate from a coastal marine sediment
NE Blair,
CS Martens,
and
DJ Des Marais
Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh 27695, USA.
Measurements of the natural abundances of carbon isotopes were made in acetate samples isolated from the anoxic marine sediment of Cape Lookout Bight, North Carolina. The typical value of the total acetate carbon isotope ratio (delta 13C) was -16.1 +/- 0.2 per mil. The methyl and carboxyl groups were determined to be -26.4 +/- 0.3 and -6.0 +/- 0.3 per mil, respectively, for one sample. The isotopic composition of the acetate is thought to have resulted from isotopic discriminations that occurred during the cycling of that molecule. Measurements of this type, which have not been made previously in the natural environment, may provide information about the dominant microbial pathways in anoxic sediments as well as the processes that influence the carbon isotopic composition of biogenic methane from many sources.
