title: Biomarker evidence for a major preservation pathway of sedimentary organic carbon.
abstract: Hydrogenation processes leading from biomolecules to fossil biomarkers in anoxic sediments are crucial for the preservation of organic matter. However, these processes are still poorly understood. The present identification of several reduced carotenoids in recent sediments attests that these processes operate at the earliest stages of diagenesis without structural or stereochemical specificity, implying a nonbiological reduction pathway. Sulfur species (e.g., H2S) are the hydrogen donors involved in such reduction, as demonstrated with laboratory experiments. These reactions allow the preservation of abundant organic carbon in the rock record.
authors.affiliation: Laboratoire de Géochimie Bioorganique, Unité Mixte de Recherche 7509 du CNRS, Université Louis Pasteur, Ecole de Chimie, Polymères, Matériaux de Strasbourg, 25 rue Becquerel, 67200 Strasbourg, France.
authors.forename: Y
authors.initials: Y
authors.lastname: Hebting
authors.forename: P
authors.initials: P
authors.lastname: Schaeffer
authors.forename: A
authors.initials: A
authors.lastname: Behrens
authors.forename: P
authors.initials: P
authors.lastname: Adam
authors.forename: G
authors.initials: G
authors.lastname: Schmitt
authors.forename: P
authors.initials: P
authors.lastname: Schneckenburger
authors.forename: S M
authors.initials: SM
authors.lastname: Bernasconi
authors.forename: P
authors.initials: P
authors.lastname: Albrecht
mesh_terms: D000693:Anaerobiosis; D001419:Bacteria / Q000378:metabolism; D002244:Carbon / Q000737:chemistry* / Q000378:metabolism; D002338:Carotenoids / Q000737:chemistry; D002384:Catalysis; D019414:Chlorobi / Q000737:chemistry / Q000378:metabolism; D002783:Cholestenones / Q000737:chemistry; D002841:Chromatiaceae / Q000737:chemistry / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D019015:Geologic Sediments / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D006862:Hydrogen Sulfide / Q000737:chemistry / Q000378:metabolism; D007659:Ketones / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D015394:Molecular Structure; D009930:Organic Chemicals / Q000737:chemistry* / Q000378:metabolism; D010084:Oxidation-Reduction; D010839:Phytoplankton / Q000737:chemistry / Q000378:metabolism; D013237:Stereoisomerism; D013557:Switzerland; D019207:beta Carotene / Q000737:chemistry
chemical_list: D002783:Cholestenones; D007659:Ketones; D009930:Organic Chemicals; D019207:beta Carotene; D002338:Carotenoids; C030311:4,6-cholestadien-3-one; D002244:Carbon; D006859:Hydrogen; D006862:Hydrogen Sulfide