Abstract:Excavated in 1974, the Quanzhou Bay Song Dynasty shipwreck is the first large and early wooden sailboat for ocean trades excavated in China. It is not only a precious national grade-one cultural relic with important conservation value, but also a rare material for studying the history of China’s ancient overseas transportation, foreign trade and shipbuilding, etc. As a precedent for the conservation of large marine wooden relics in China and Asia, the Quanzhou Bay Song Dynasty shipwreck has been preserved for many years. After years of integrated conservation and restoration, the status of the shipwreck deserves attention. The action of microorganisms is one of the important biological factors causing wood degradation. The microbial hazard of wood is mainly caused by fungi such as wood-decay fungi, coloring fungi and molds, as well as some bacteria that can decompose cellulose. Therefore, the analysis of microbial communities in wooden cultural relics is not only an important strategy for the preventive conservation of wooden cultural relics, but also an important guarantee for efficient conservation to avoid the microbial hazard. In order to understand the population and distribution law of microorganisms in the currently preserved hull, samples from 25 different regions from the bow to the cabin and the stern were collected. Microbial high-throughput amplification sequencing was used to analyze the microbial composition groups and distribution laws of the hull, which is composed of different wood types, and to determine whether there were harmful, corrosive microbial groups in the current hull. The results of sequencing analysis show that there were stable and abundant microbial groups in all parts of the hull. Although there are some differences in the composition of bacterial and fungal communities in different parts of the hull, these differences are not significantly related to the wood type and structural position of the hull. The dominant bacterial species in different preservation areas of the hull are Acinetobacter sp. (13.65%), Bacillus sp. (6.88%) and Pseudomonas sp. (3.69%), and the dominant fungal species are Cladosporium sp. (12.26%), Candida sp. (5.93%) and Lophiostoma sp. (5.66%). In addition, the species of Bacillus, Streptococcus, Cladosporium and Aspergillus found in this study have strong abilities to degrade wood cellulose. The growth and outbreak of these microorganisms under certain environmental conditions will threaten the preservation of the hull. Therefore, in the subsequent conservation of the hull, the prevention and treatment to avoid the microbial hazard should be carried out regularly, and the temperature and humidity of the storage environment of the hull should be controlled strictly, so as to benefit the long-term preservation of the hull. This study systematically analyzed the microbial community structural composition of various parts of the Quanzhou Bay Song Dynasty shipwreck for the first time, and evaluated the risk of the microbial hazard for the public exhibition of the ship held by Quanzhou Maritime Museum Fujian, so as to provide an important reference for the following preventive conservation of the Song Dynasty shipwreck against microbial degradation in the future.