Stable carbon isotopes of lipid biomarkers: analysis of metabolites and metabolic fates of environmental microorganisms.

Lipid biomarkers are specific compounds that are characteristic of certain groups or species of microorganisms. The use of natural or labeled carbon isotopes of lipid biomarkers has enabled a better understanding of carbon flow pathways at the molecular level. Recent advances include, but are not limited to, the elucidation of mechanisms of anaerobic methane oxidation mediated by syntrophic sulfate-reducing bacteria and Archaea, linking microbial populations with specific microbial processes or bacterial transport mechanisms in natural or contaminated environments, and elucidation of the biosynthetic pathways of cellular material.