The individual fatty acids of mytilids and vestimentiferan (Escarpis sp.) from hydrocarbon seeps exhibit light δ13Cvalues: from -56.9 to -49.0‰ for the mytilids and from -38.6 to -31.6‰ for the vestimentiferan. Unsaturated fatty acids have lighter δ13C than saturated ones. The variations in δ13C are up to 5.1-6.7‰ (mytilids) and 7.0‰ (vestimentiferan) within a single specimen. It is suggested that a kinetic isotopic effect in the biosynthesis of fatty acids and intermolecular isotope fractionation during fatty acid desaturation and elongation are responsible for the observed distribution pattern. Fatty acids are depleted in 13C relative to the gills of the mytilids, whereas fatty acids of the vestimentiferan are enriched relative to trophosomes. The difference in δ13C of fatty acids between mytilids and vestimentiferan reflects the differences in substrates (methane vs. CO2), and the different chemosynthetic processes of the invertebrates.
ASJC Scopus subject areas
- Geochemistry and Petrology