Analysis of microbial community and biodeterioration of maritime cultural relics (ironware, porcelain, axes, hull wood) from the Nanhai No. 1 shipwreck

Purpose Maritime cultural relics from the Nanhai No. 1 shipwreck were immersed in a buffer to maintain stability. To better monitor the changes in the composition of microorganisms in the buffer and, thus, prevent the damage to artifacts caused by harmful microorganisms. Methods In September and November 2019, we conducted high-throughput sequencing of water samples from four types of maritime cultural relics (ironware, porcelain, axe, and hull wood) to reveal the composition and changes in microbial communities. In addition, we isolated culturable microorganisms and conducted biocide sensitivity tests and lignin and cellulose degradation tests. Results Visible microbial colonization was observed in the water samples collected from the buffer solutions of ironware, porcelain, axe, and hull wood of the Nanhai No. 1 shipwreck; additionally, apparent differences in the composition of microorganisms in the water samples collected from different cultural relics and different collection times of the same cultural relics were noted. Few species of bacteria and fungi from the microbial community observed in the maritime cultural relics were cultured, and it was noted that various biocides had certain inhibitory effects on them. Some dominant strains had lignin and cellulose degradation abilities and could only grow under specific environmental conditions. Conclusion We found apparent differences in the composition of microorganisms obtained from different cultural relics and different collection times of the same cultural relics. This study can provide data support for better protection of maritime cultural relics obtained from the Nanhai No. 1 shipwreck and provide a theoretical basis for the biological protection of other maritime cultural relics.