Microbial decay of waterlogged archaeological wood found in Sweden Applicable to archaeology and conservation

Björdal, Charlotte Gjelstrup; Nilsson, Thomas; Daniel, Geoffrey

doi:10.1016/s0964-8305(98)00070-5

Cited by 185 publications

(124 citation statements)

References 7 publications

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“…In addition to structural instability, biological degradation from marine organisms and water-borne microbes has also become a major conservation issue over time. To combat biological degradation, broad spectrum biocides have generally been added to the polymer solutions during the conservation process (Bjordal et al, 1999;May & Jones, 2008). In the case of the Mary Rose, a biocide known as PhaseChem305 was used (Jones, 2013), resulting in timbers that retain their structure after drying and are less prone to biological attack.…”

Section: Introductionmentioning

confidence: 99%

“…It is important to consider the three most important issues affecting the conservation of the Mary Rose, which will determine the applicability of any alternative material. These are structural instability upon drying (Giachi et al, 2010), biological degradation (Bjordal et al, 1999;May & Jones, 2008) and, more recently discovered, the build-up of Fe 3+ from corroded iron bolts that can catalyse the production of acid in the timbers (Sandström et al, 2002;Fors & Sandström, 2006;Almkvist & Persson, 2008b, 2008c. Ultimately, the ability to address these conservation issues will determine the future of any alternative consolidant materials.…”

Section: Introductionmentioning

confidence: 99%

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Natural polymers as alternative consolidants for the preservation of waterlogged archaeological wood

Walsh

Janeček

Jones

et al. 2016

Studies in Conservation

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In recent years, there has been increased interest in examining alternative polymers for the conservation of archaeological artefacts, particularly waterlogged timbers, providing better, renewable, greener alternatives to poly(ethylene glycol) (PEG). The degradation of PEG consolidants in the timbers of the sixteenth century warship Mary Rose has been examined and the rheological and thermal properties of PEG have been compared with its monomethyl and dimethyl ethers and several polysaccharide consolidants (chitosan, guar, and 2-hydroxyethyl cellulose) in order to evaluate their potential as alternative consolidants for the conservation of waterlogged wooden artefacts. Additionally, the effect of the polymers on the archaeological wood was characterised by thermogravimetric analysis and solid-state nuclear magnetic resonance spectroscopy. The results suggest that the future of conservation technologies lies with polysaccharide consolidant materials, which show enhanced compatibility with wooden artefacts with no detectable side effects while also being cheap, with extremely low toxicity, renewable, and sustainably resourced.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Natural polymers as alternative consolidants for the preservation of waterlogged archaeological wood

Walsh

Janeček

Jones

et al. 2016

Studies in Conservation

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“…The variation in mechanical performance at different positions in the enormous ship's structure is therefore expected to be larger than that in recent European oak. In General, waterlogged archaeological wood undergoes physical and chemical modifications as a result of erosion bacteria in anaerobic conditions, for example, causing the separation of the secondary cell-wall layers [2,3,20]. As the microstructure of the cell wall governs the strength characteristics in wood, cell-wall decomposition severely reduces the strength [6,7].…”

Section: Mechanical Characteristics Of Archaeological Wood and Influementioning

confidence: 99%

“…This could be achieved by the relationships established between PEG content, density and the MOE in Step 2. The PEG content, however, varies in depth [8,20] and has a negative impact on the mechanical performance [38,39]. As it is impossible to monitor the depth of the PEG visually or by X-ray, a general PEG profile, based on previous measurements from different locations on the Vasa warship and at different depths, will serve as a further link to estimate the stiffness properties in terms of MOE of structural elements.…”

Section: Relationship Between Density Moe and Peg Distributionmentioning

confidence: 99%

Strategy for developing a future support system for the Vasa warship and evaluating its mechanical properties

2013

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To maintain the integrity of the Vasa warship after salvage in 1961, conservation treatment with polyethylene glycol was carried out to prevent the collapse of cell walls. This treatment had negative effects on the strength and stiffness of the oak and the hull structure has been found to slowly deform over time. It is of interest to construct a three-dimensional numerical computer model to model and predict the deformation of the warship. This creates difficulties related to the complexity of measuring the detailed material properties that are required as input. In this context, a non-destructive methodology to predict the stiffness of the Vasa oak in terms of moduli of elasticity in the three principal directions of timber at critical positions in the ship would be useful. The twofold aim of the paper is to propose a strategy for a support system and to conduct an on-site assessment of the warship to predict the mechanical properties of the Vasa oak material. This paper also contains an up-to-date review of all essential mechanical data measured on the Vasa oak. The preliminary investigation using an X-ray technique to investigate the density properties produced promising results for future use in the evaluation of the mechanical performance. Based on these results, a procedure to establish the stiffness properties of the Vasa oak in terms of MOE was suggested, using a combination of data from previous measurements, in combination with extended tests on Vasa oak specimens and an X-ray-based density calibration procedure. The general complexity of the Vasa warship can be mainly attributed to large variations in the properties of Vasa oak due to surface degradation, chemical treatment and the disintegration of the cell-wall structure originating from centuries of waterlogged conditions. That causes difficulties when assessing mechanical and physical properties on a structural level. A combination of visual inspection together with X-ray investigation is of great importance to evaluate those properties and to obtain more accurate estimates. The results from evaluating mechanical properties can serve as input in a numerical model and serve as a foundation for decision-making relating to the modification of the support system.

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“…Furthermore, studies of wood exposed to underwater conditions can be used to provide support to the search for new information about underwater archaeological objects (Björdal 1999, Jensen and Gregory 2006, Tamburini et al 2014, flooded forests (Kooye 2011, Tenenbaum 2004, and wood underwater to preserve its structure before some industrial application.…”

Section: Introductionmentioning

confidence: 99%

Wood under fresh water: Effect on the chemical properties and on decay resistance

Lourençon

Santos

Labidi

et al. 2016

Maderas, Cienc. tecnol.

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This study aimed to evaluate the effect of waterlogging on the chemical properties and on decay resistance of two fast-growing eucalypt species. Samples of spotted gum and rose gum wood were placed underwater and taken out at different times: after 4, 8 and 12 months. Chemical properties were performed via wet chemical quantification (Tappi standards), monomeric sugars by HPLC, and qualitative evaluation of extractives by Py-GC/MS and ATR-IR spectroscopy; biological performance was investigated using Trametes versicolor and Gloeophyllum trabeum rot fungi. The results showed slight changes to the chemical properties of both wood species, with an increase in lignin represented by the reduction of sugars due to waterlogging. Both species showed higher susceptibility to Gloeophyllum trabeum mainly in the sapwood, with no influence on decay resistance due the waterlogging.

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Microbial decay of waterlogged archaeological wood found in Sweden Applicable to archaeology and conservation

Cited by 185 publications

References 7 publications

Natural polymers as alternative consolidants for the preservation of waterlogged archaeological wood

Natural polymers as alternative consolidants for the preservation of waterlogged archaeological wood

Strategy for developing a future support system for the Vasa warship and evaluating its mechanical properties

Wood under fresh water: Effect on the chemical properties and on decay resistance

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