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Research Article| October 01, 2008 Sulfidity controls molybdenum isotope fractionation into euxinic sediments: Evidence from the modern Black Sea Nadja Neubert; Nadja Neubert 11Institute of Geological Sciences, Isotope Geology Group, University of Bern, CH-3012 Bern, Switzerland Search for other works by this author on: GSW Google Scholar Thomas F. Nägler; Thomas F. Nägler 11Institute of Geological Sciences, Isotope Geology Group, University of Bern, CH-3012 Bern, Switzerland Search for other works by this author on: GSW Google Scholar Michael E. Böttcher Michael E. Böttcher 22Leibniz Institute for Baltic Sea Research, Marine Geochemistry Group, Warnemünde, Germany, and Max Planck Institute for Marine Microbiology, Biogeochemistry Department, Bremen, Germany Search for other works by this author on: GSW Google Scholar Geology (2008) 36 (10): 775–778. https://doi.org/10.1130/G24959A.1 Article history received: 17 Mar 2008 rev-recd: 08 Jun 2008 accepted: 16 Jun 2008 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Nadja Neubert, Thomas F. Nägler, Michael E. Böttcher; Sulfidity controls molybdenum isotope fractionation into euxinic sediments: Evidence from the modern Black Sea. Geology 2008;; 36 (10): 775–778. doi: https://doi.org/10.1130/G24959A.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Molybdenum (Mo) isotope fractionation has recently been introduced as a new proxy in oceanography and biogeochemistry. It is therefore fundamental to understand the processes controlling Mo partitioning into modern marine environments. This study identifies the availability of dissolved sulfide as the dominant control on overall Mo removal from the water column in euxinic systems. Mo isotopic composition of surface sediments from different localities of the Black Sea demonstrates complete fixation of Mo only below 400 m water depth, above a critical concentration of 11 μmol l−1 aqueous hydrogen sulfide in the bottom water. The Mo isotopic composition of these sediments reflects the homogeneous seawater isotopic composition of 2.3‰. In contrast, significant Mo isotope fractionation into less euxinic sediments is evident at shallower depths in the Black Sea, as well as in temporarily euxinic deeps of the Baltic Sea, consistent with the observed lower maximum sulfide concentrations in the respective water columns. Therefore, Mo isotope signatures in the modern Black Sea constrain the processes responsible for global Mo removal from the ocean by euxinic sediments. Furthermore, models of past ocean anoxia reconstruction have to consider that the seawater Mo isotopic composition is not per se archived in euxinic sediments. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.