Structure and diversity of microbial community on the surface of pottery figurines in the Hanyang Mausoleum

Abstract:

[Background] Han Yangling Museum has been the largest group of pottery figurines of the Han Dynasty so far found in China. A large number of nude figurines have been unearthed. Archaeologists believe that these nude pottery figurines were originally dressed and equipped with wooden arms, which are unique to the royal family and extremely precious. However, there is no scientific support for these conjectures. In addition, the microorganisms attached to the surface may corrode the pottery figurines. [Objective] To provide scientific evidence for the speculation that clothes and broken arms exist by comparing the structure of microbial community on the surface of the pottery figurines, and to provide targets for the prevention and control of the microbial corrosion of pottery figurines in the Han Dynasty. [Methods] The microorganisms on different parts of the pottery figurines were identified by high-throughput sequencing and pure culture method. [Results] The high-throughput sequencing results showed that the microbial diversity in female figurines was higher on the head. In male figurines, the microbial diversity was high on the upper body, moderate on the legs, and low on the head. The microbial taxa on the surface of the pottery figurines were clustered according to the types and different parts of the figurines. The dominant groups were Clostridia, Saccharopolyspora, Pseudonocardia, and Streptomycetaceae of Actinomycetes. The relative abundance of dominant groups varied in different parts, and the relative abundance of the functional microorganisms involved in the carbon cycle on broken arms was the highest. The culturable bacteria on the head of female figurines were more than those on the head of male figurines. The culturable microorganisms on the upper body and legs were more than those on the head in male figurines. The upper body and legs may have been covered by clothing, which provided the habitats with different nutrients for microorganisms. [Conclusion] There were significant differences in microbial diversity and composition between the head and the body of the pottery figurines in the Han Dynasty, which suggested that the nutrient composition varied in different parts of the pottery figurines. Such differences might be related to the covering of the pottery figurines with clothes or dye.