Microbial community analysis and biodeterioration of waterlogged archaeological wood from the Nanhai No. 1 shipwreck during storage

Abstract

Wooden shipwrecks are a significant part of the underwater cultural heritage. In 2007, the Nanhai No. 1 shipwreck was salvaged from the seabed and moved into the Marine Silk Road Museum, where it is still stored in a water tank. We analysed the microbial communities colonizing the hull surface of the Nanhai No. 1 shipwreck during storage. Six samples exposed to air were collected from different spots of the ship that exhibited obvious microbial plaques. High-throughput sequencing revealed the bacterial community includes both aquatic and terrestrial species, while in the fungal community, Fusarium was the most abundant genus across all samples and accounted for 84.91% to 98.40% of the total community composition. Two Fusarium species were isolated from the samples and were identified as F. solani and F. oxysporum. Both of the isolates were able to degrade cellulose, but only F. solani had the ability to degrade lignin. Antimicrobial efficacy in inhibiting the growth of Fusarium was assessed with five kinds of biocides, and isothiazolinones exhibited specific inhibition of Fusarium growth. These results provide critical background information to protect and reduce the biodegradation and destruction of this important historical shipwreck, and inform efforts to protect other similar artifacts.

Fungal Community Analyses of a Pirogue from the Tang Dynasty in the National Maritime Museum of China

“…For the study of fungal community, internal transcribed spacer 1 (ITS1) was amplified with the universal fungal primers ITS5-1737F/ITS2-2043R [17,18] (Table S2). The amplification reaction mixture and PCR program were prepared as described Liu et al [4]. Samples with amplicon bands in the range of 500-700 bp were selected for further analysis.…”

“…The CMC agar consisted of 0.2% NaNO 3 , 0.1% K 2 HPO 4 , 0.05% MgSO 4 , 0.05% KCL, 0.2% carboxymethylcellulose sodium (CMC-Na), 0.02% peptone, 1.7% agar and 1 L of tap water [23]. Specific methods of operation can be found in the literature described by Liu et al [4]. Each test comprised three replicates.…”

“…1 shipwreck, preserved in the Yangjiang Museum, was severely attacked by Fusarium sp. due to a change in the environment [4]. Fungi has also been discovered on wooden historical objects in a regional museum [5].…”

Bacterial and Biodeterioration Analysis of the Waterlogged Wooden Lacquer Plates from the Nanhai No. 1 Shipwreck

“…Second, the application of efficient and low-toxicity biocides may be considered to restrain bacterial growth and mitigate biodeterioration [39]. Although the biocide susceptibility test illustrated the great capacity of biocides to chemically repress the growth of prominent bacteria, biocides can exert pressure on microbial communities, resulting in the development of biocide-resistant mechanisms or the replacement of dominant bacteria with new microbial communities, which may bring about more serious damage to cultural artifacts [2]. For example, in the French Lascaux Cave, a series of biocide treatments were applied that led to new microbial outbreaks [40].…”

“…The discovery of the Nanhai No. 1 shipwreck is an unprecedented achievement and a historical landmark for Chinese underwater archaeology [2].…”