Sulfur accumulation in the timbers of King Henry VIII's warship Mary Rose : A pathway in the sulfur cycle of conservation concern

Abstract

In marine-archaeological oak timbers of the Mary Rose large amounts of reduced sulfur compounds abound in lignin-rich parts such as the middle lamella between the cell walls, mostly as thiols and disulfides, whereas iron sulfides and elemental sulfur occur in separate particles. Synchrotron-based x-ray microspectroscopy was used to reveal this environmentally significant accumulation of organosulfur compounds in waterlogged wood. The total concentration of sulfur in reduced forms is Ϸ1 mass % throughout the timbers, whereas iron fluctuates up to several mass %. Conservation methods are being developed aiming to control acid-forming oxidation processes by removing the reactive iron sulfides and stabilizing the organosulfur compounds.organosulfur ͉ waterlogged wood ͉ iron sulfides ͉ conservation ͉ marine archaeology

Assessing Potential Acidification of Marine Archaeological Wood Based on Concentration of Sulfur Species

“…The surviving timbers of the Mary Rose were embedded in clay and buried with silt, resting in an anaerobic environment in situ [9]. The presence of sulfonate suggests that during its 450 year burial period our sample must have come into contact with dissolved oxygen for an extended period of time.…”

The application of X-ray absorption spectroscopy in archaeological conservation: Example of an artefact from Henry VIII warship, the Mary Rose

“…The reaction pathways are complex and can be both abiotic and biotic, as sulfur-oxidising microorganisms will also produce sulfuric acid. The problem is exacerbated in iron rich regions as iron is believed to catalyse the production of sulfuric acid [26,33,42,43]. For the conservator the challenges are firstly to understand the underlying processes and secondly to develop a remediation strategy which has to provide long-term protection for the timbers.…”

“…In the case of the Mary Rose the measurements have been used to identify the iron and sulfur compounds in the timbers [32,33] and to determine the effectiveness of chemical treatments to remove iron [34,45] or the use of nanoparticles to neutralise sulfuric acid in the wood [35,37,38,40]. The technique has also been used to study bacteria that could be in the timbers [39] and in long-term monitoring of iron and sulfur compounds of the ship in the museum environment [44].…”

“…There is an enormous breadth of problems to which the technique has been applied; ranging from the origin of Ancient Greek (5th century BCE) burial vessels [20], to the deterioration of medieval stained glass windows [21], to degradation of historic documents by iron gall ink [22] and to the origin of van Gogh's yellow paint [23]. Artefacts that have been a particular focus for XAS studies are waterlogged archaeological timbers, namely the historic ships the Vasa [24][25][26][27][28][29][30][31] and the Mary Rose [32][33][34][35][36][37][38][39][40]. It is this latter ship that has been of interest to the current group of authors with a special interest in the 'sulfur problem'.…”

Novel Bacterial Community Associated with 500-Year-Old Unpreserved Archaeological Wood from King Henry VIII's Tudor Warship the Mary Rose

“…Iron sulfides (FeS and FeS 2 ) form when hydrogen sulfide ions react with available Fe 2ϩ (33,42), such as soluble Fe(II) ions from corroding iron nails used during the construction of the Mary Rose (4). Approximately 1 mass percent sulfur is present in the Mary Rose hull, of which pyrite (FeS 2 ) accounts for a third of the total reduced sulfur (34). The oxidation of RISCs upon excavation, and the resulting production of sulfuric acid, is of major conservation concern, as acid hydrolysis of cellulose and hemicellulose diminishes wood strength and structure and, with mostly lignin remaining, leads to cellular collapse.…”