1. Plant Wax n ‐Alkane and n ‐Alkanoic Acid Signatures Overprinted by Microbial Contributions and Old Carbon in Meromictic Lake Sediments
- Author
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Ingrid Antheaume, Vincent Grossi, Daniel B. Montluçon, Matthew Makou, Timothy I. Eglinton, Cameron McIntyre, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Chimie Et Interdisciplinarité : Synthèse, Analyse, Modélisation (CEISAM), Université de Nantes - Faculté des Sciences et des Techniques, and Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
010504 meteorology & atmospheric sciences ,meromictic lake ,chemistry.chemical_element ,010502 geochemistry & geophysics ,01 natural sciences ,law.invention ,n-alkane ,compound specific radiocarbon analysis ,law ,plant wax ,[CHIM]Chemical Sciences ,Radiocarbon dating ,Alkanoic acid ,ComputingMilieux_MISCELLANEOUS ,0105 earth and related environmental sciences ,Alkane ,chemistry.chemical_classification ,Wax ,Hard water ,Geophysics ,Deposition (aerosol physics) ,chemistry ,[SDU]Sciences of the Universe [physics] ,13. Climate action ,Environmental chemistry ,visual_art ,[SDE]Environmental Sciences ,Soil water ,n-alkanoic acid ,visual_art.visual_art_medium ,biomarker ,General Earth and Planetary Sciences ,Carbon - Abstract
International audience; Specific n-alkanes and n-alkanoic acids are commonly used as biomarkers in paleoenvironmental reconstruction, yet any individual homologue may originate from multiple biological sources. Here we improve source and age controls for these compounds in meromictic systems by measuring the radiocarbon (C-14) ages of specific homologues preserved in twentieth century Lake Pavin (France) sediments. In contrast to many studies, C-14 ages generally decreased with increasing carbon chain length, from 7.3 to 2.6 ka for the C-14-C-30 n-alkanoic acids and from 9.2 to 0.3 ka for the C-21-C-33 n-alkanes. Given a known hard water effect, these values suggest that aquatic microbial sources predominate and contributed to most of the homologues measured. Only the longest chain n-alkanes exclusively represent inputs of higher plant waxes, which were previously sequestered in soils over centennial to millennial timescales prior to transport and deposition. These findings suggest that biomarker source and age should be carefully established for lacustrine settings.
- Published
- 2018
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