Trace element systematics in cold seep carbonates and associated lipid compounds

Type Article
Date 2019-12
Language English
Author(s) Wang Xudong1, 2, 7, 8, Bayon Germain2, Kim Jung-Hyun3, Lee Dong-Hun4, Kim Dahae3, Guéguen Bleuenn5, Rouget Marie-Laure5, Barrat Jean-Alix5, Toffin LaurentORCID6, Feng Dong1, 7
Affiliation(s) 1 : Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
2 : IFREMER, Marine Geosciences Unit, F-29280 Plouzané, France
3 : KOPRI Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 21990, South Korea
4 : Hanyang University, 55 Hanyangdaehak-ro, Sangrok-gu, Ansan 15588, Republic of Korea
5 : Laboratoire Géosciences Océan, Université de Bretagne Occidentale et Institut Universitaire Européen de la Mer, Place Nicolas Copernic, 29280 Plouzané, France
6 : IFREMER, UMR6197, Laboratoire Microbiologie des Environnements Extrêmes, F-29280 Plouzané, France
7 : Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou 510301, China
8 : University of Chinese Academy of Sciences, Beijing 100049, China
Source Chemical Geology (0009-2541) (Elsevier BV), 2019-12 , Vol. 528 , P. 119277 (18p.)
DOI 10.1016/j.chemgeo.2019.119277
WOS© Times Cited 9
Keyword(s) Seep carbonate, Lipid compounds, Trace elements, Tungsten, Nickel, Cobalt, Molybdenum

Seeping of methane-rich fluids at submarine cold seeps drives intense microbial activity and precipitation of authigenic carbonates. Some trace elements play an important role in the biogeochemical processes operating at cold seeps, especially as specific enzymatic co-factors related to methanogenesis and the anaerobic oxidation of methane (AOM). However, it is unclear whether microbial trace metal utilization can be traced by the geochemical composition of seep carbonates. In this study, we analyzed a series of authigenic carbonate samples recovered from various seep settings worldwide and report for the first time trace element concentrations for total lipid fractions, combined with biomarker analyses and determination of elemental abundances in associated inorganic mineral phases (carbonate phases, sulfides, organic compounds and detrital fractions). Our results indicate marked enrichments of Co, Ni, Cu, Mo and W in the archaeal and bacterial lipids associated with authigenic carbonates, which can all be ascribed to previously identified enzymatic pathways. In addition to the microbial communities involved in AOM, which most likely control specific lipid-bound enrichments of Co, Ni, Mo and W in seep carbonates, Cu was found to display higher concentrations in the lipid fractions extracted from a few authigenic carbonate samples formed closer to the sediment-water interface, hence possibly related to the presence of aerobic methane-oxidizing bacterial assemblages in the near seafloor environment. While the above mentioned trace metals are relatively enriched in all studied inorganic and organic fractions, the very low W concentrations measured in carbonate phases, combined with their pronounced enrichment in associated lipid fractions and inferred microbial requirement, suggest that tungsten depletion in pore waters could possibly act as a limiting factor on AOM at cold seeps. Finally, two other trace elements (Li and Ti) also displayed particular enrichments in studied lipid fractions, which, despite no reported evidence, could possibly indicate that they are also involved as metalloenzymes in microbial methane oxidation processes at cold seeps.

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