@article{7ebec277117e4f1799d1e0333df6b123,
title = "Authigenic metastable iron sulfide minerals preserve microbial organic carbon in anoxic environments",
abstract = "The burial of organic carbon (OC) in sedimentary environments promotes long-term carbon sequestration, which allows the release of oxygen in the atmosphere. Organo-mineral interactions that form between terrigenous minerals and OC during transport to and deposition on the seabed enhance OC preservation. Here, we propose an authigenic mechanism for the coupled preservation of labile OC and metastable iron sulfide minerals under anoxic conditions. Sulfate-reducing microorganisms (SRM) are ubiquitous in anoxic environments and produce the majority of free sulfide in marine sediments, leading to the formation of iron sulfide minerals in situ. Using high spatial resolution microscopy, spectroscopy and spectro-microscopy, we show that iron sulfide biominerals precipitated in the presence of SRM incorporate and adsorb organic molecules, leading to the formation of stable organo-mineral aggregates that could persist for years in anoxic environments. OC/iron sulfide assemblages consist of the metastable iron sulfide mineral phases mackinawite and/or greigite, along with labile organic compounds derived from microbial biomass or from organic molecules released extracellularly by SRM. Together these results underscore the role that a major group of anoxic microbes play in OC preservation and illustrate the value of the resulting authigenic metastable iron sulfide minerals mackinawite and greigite in protecting labile organic molecules from degradation over time.",
author = "Aude Picard and Amy Gartman and Julie Cosmidis and Martin Obst and Charles Vidoudez and Clarke, {David R.} and Girguis, {Peter R.}",
note = "Funding Information: We would like to thank the editor and two reviewers for helping to improve the manuscript significantly. This work was performed in part at the Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Coordinated Infrustructure Network (NNCI), which is supported by the National Science Foundation under NSF award no. 1541959. CNS is part of Harvard University. We thank the Harvard Center for Biological Imaging for infrastructure and support. We thank Shao-Liang Zheng for support at the X-ray laboratory of the Department of Chemistry and Chemical Biology, Harvard University. This research used resources of the Advanced Light Source, which is a DOE Office of Science User Facility under contract no. DE-AC02-05CH11231. Research described in this paper was partly performed at the Canadian Light Source, which is supported by the Canada Foundation for Innovation, Natural Sciences and Engineering Research Council of Canada, the University of Saskatchewan, the Government of Saskatchewan, Western Economic Diversification Canada, the National Research Council Canada, and the Canadian Institutes of Health Research. We thank the staff of beamlines and analytical facilities for support. This work was supported by the National Science Foundation under Grant Numbers NSF-1344241, NSF-1542506 and OCE-1635365 awarded to P.R.G. M.O. was supported by DFG grant OB 362/4-1. J.C. was supported by the Colorado Advanced Industries Accelerator Program (POGGI 2016-1054 0842), sponsored by the Colorado Office of Economic Development, and the Rock-Powered Life 1055 NASA Astrobiology Institute (Coorperative Agreement NNS15BB02A). The authors gratefully acknowledge the support of the Deep Carbon Observatory and the Deep Energy Community. Funding Information: We would like to thank the editor and two reviewers for helping to improve the manuscript significantly. This work was performed in part at the Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Coordinated Infrustructure Network (NNCI), which is supported by the National Science Foundation under NSF award no. 1541959 . CNS is part of Harvard University. We thank the Harvard Center for Biological Imaging for infrastructure and support. We thank Shao-Liang Zheng for support at the X-ray laboratory of the Department of Chemistry and Chemical Biology, Harvard University. This research used resources of the Advanced Light Source, which is a DOE Office of Science User Facility under contract no. DE-AC02-05CH11231. Research described in this paper was partly performed at the Canadian Light Source, which is supported by the Canada Foundation for Innovation , Natural Sciences and Engineering Research Council of Canada , the University of Saskatchewan , the Government of Saskatchewan, Western Economic Diversification Canada , the National Research Council Canada, and the Canadian Institutes of Health Research . We thank the staff of beamlines and analytical facilities for support. This work was supported by the National Science Foundation under Grant Numbers NSF-1344241 , NSF-1542506 and OCE-1635365 awarded to P.R.G. M.O. was supported by DFG grant OB 362/4-1 . J.C. was supported by the Colorado Advanced Industries Accelerator Program (POGGI 2016-1054 0842 ), sponsored by the Colorado Office of Economic Development, and the Rock-Powered Life 1055 NASA Astrobiology Institute (Coorperative Agreement NNS15BB02A ). The authors gratefully acknowledge the support of the Deep Carbon Observatory and the Deep Energy Community . Publisher Copyright: {\textcopyright} 2019 Elsevier B.V.",
year = "2019",
month = dec,
day = "30",
doi = "10.1016/j.chemgeo.2019.119343",
language = "English (US)",
volume = "530",
journal = "Chemical Geology",
issn = "0009-2541",
publisher = "Elsevier",
}
