Analysis of the bacterial communities in the waterlogged wooden cultural relics of the Xiaobaijiao No. 1 shipwreck via high-throughput sequencing technology

Abstract

Abstract The microbial impact on waterlogged wooden cultural relics from Xiaobaijiao No. 1 shipwreck was investigated by means of a high-throughput sequencing technology, while the focus was on the composition of prokaryotic microorganisms in 10 wood samples collected from different parts of the shipwreck. A total of 28 501 different operational taxonomic units (OTUs) were obtained based on 97% sequence similarity. The α-diversity index is for the bacterial diversity, which was the highest and the lowest in the samples SS8 and SS5, respectively. Proteobacteria was the largest category of bacterial abundance (47.3%) followed by Bacteroidetes (10%). α-Proteobacteria was the first largest bacteria class with the maximum abundance (21.0%) followed by γ-Proteobacteria (16.9%). Other groups rich in the following species were found: Bacteroidales (13.3%), Thiotrichales (5.0%), Rhodobacterales (4.2%), Rhizobiales (4.0%), Chromatiales (3.5%), Oceanospirillales (3.3%), Flavobacteriales (2.9%) and Sphingomonadales (2.8%). At the level of the bacterial genus, Marinomonas was the most abundant one. Phylogenetic analysis revealed that there are some differences in the composition of bacterial communities from different wood samples. The species number of bacteria in the relics of this shipwreck was far more than that reported in those found in Europe, and in which species composition was similar to the benthic bacteria in the corresponding sea area. The coexistence of anaerobic and aerobic bacteria is remarkable.