Distributions and carbon isotopic compositions of lipid biomarkers in authigenic carbonate crusts from the Nordic margin (Norwegian Sea)

We investigated the distributions and δ13C values of lipid biomarkers in authigenic carbonate crusts from the Nordic margin (Norwegian Sea). Abundant, highly 13C-depleted archaeal and bacterial biomarkers revealed that anaerobic oxidation of methane (AOM) is associated with carbonate authigenesis at the Håkon Mosby Mud Volcano (HMMV) and the Nyegga pockmark field. No conclusive evidence for AOM was found in the crust sample from the Storegga Slide. ANME-2 methanotrophic archaea and sulfate-reducing bacteria from the Desulfosarcina/Desulfococcus cluster were inferred from lipid fingerprints. Distinct patterns of 13C-depleted, non-isoprenoid dialkyl glycerol diethers (DAGEs) are possibly associated with unknown microbial partners in the AOM.