title: Sulfur and iron accumulation in three marine-archaeological shipwrecks in the Baltic Sea: the Ghost, the Crown and the Sword.
abstract: Sulfur and iron concentrations in wood from three 17(th) century shipwrecks in the Baltic Sea, the Ghost wreck, the Crown and the Sword, were obtained by X-ray fluorescence (XRF) scanning. In near anaerobic environments symbiotic microorganisms degrade waterlogged wood, reduce sulfate and promote accumulation of low-valent sulfur compounds, as previously found for the famous wrecks of the Vasa and Mary Rose. Sulfur K-edge X-ray absorption near-edge structure (XANES) analyses of Ghost wreck wood show that organic thiols and disulfides dominate, together with elemental sulfur probably generated by sulfur-oxidizing Beggiatoa bacteria. Iron sulfides were not detected, consistent with the relatively low iron concentration in the wood. In a museum climate with high atmospheric humidity oxidation processes, especially of iron sulfides formed in the presence of corroding iron, may induce post-conservation wood degradation. Subject to more general confirmation by further analyses no severe conservation concerns are expected for the Ghost wreck wood.
authors.affiliation: Department of Conservation, University of Gothenburg, Sweden.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Fors
authors.affiliation: Bolin Centre for Climate Research, Department of Physical Geography and Quaternary Geology, Stockholm University, Sweden.
authors.forename: Håkan
authors.initials: H
authors.lastname: Grudd
authors.affiliation: Cox Analytical Systems, Mölndal, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Rindby
authors.affiliation: Department of Chemistry, University of Calgary, Canada.
authors.forename: Farideh
authors.initials: F
authors.lastname: Jalilehvand
authors.affiliation: Department of Materials and Environmental Chemistry, Stockholm University, Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: Sandström
authors.affiliation: Department of Earth Sciences, University of Gothenburg, Sweden, and Geological Survey of Sweden.
authors.forename: Ingemar
authors.initials: I
authors.lastname: Cato
authors.affiliation: Department of Earth Sciences and Department of Biology and Environmental Sciences, University of Gothenburg, Sweden.
authors.forename: Lennart
authors.initials: L
authors.lastname: Bornmalm
mesh_terms: D007501:Iron / Q000737:chemistry*; D012623:Seawater; D013455:Sulfur / Q000737:chemistry*; D014934:Wood / Q000737:chemistry* / Q000382:microbiology; D014961:X-Ray Diffraction
chemical_list: D013455:Sulfur; D007501:Iron