## 4 Discussion
There are indeed a number of wooden artifacts suffering from the biodegradation caused by bacteria. According to [PERSON] and [PERSON], several types of dominant bacteria, such as _Actinobacteria_, _Alphaproteobacteria_, _Gammaproteobacteria_, and _Acidobacteria_, were isolated from the samples collected from the Tomba della Sci mma (Tomb of the Monkey) 480-470 BC near Chiusi, Italy [31]. According to [PERSON], [PERSON], and [PERSON], the microbial decay of waterlogged archaeological wood found in Sweden was mainly caused by bacterial corrosion [32]. A similar case is also exemplified by the Xiaobaijiao shipwreck (1821-1850) in Zhejiang province [9]. Moreover, according to [PERSON], bamboo slips, belonging to the Three Kingdoms period, that were excavatedfrom Changsha, Hunan have suffered from degradation by seven genera of bacteria: _Bacillus, Acinetobacter, Staphylococcus, Pandoraea, Novosphingobium, Cupriavidus,_ and _Comanonas_[8]. Microbial interactions also have important effects on the degradation of cellulose and lignin in wood. Studies on the biodegradation of cellulose have shown that the degradation of cellulose by a single microorganism is difficult or only weak and must rely on the combined action of two or more microorganisms [33]. Due to the synergistic effect and interdependence of different species in the microbial community, it is speculated that the interaction of microorganisms in the liquid matrix may greatly improve enzyme activity and promote the degradation of cellulose. The biodegradation of lignin under natural conditions is also the result of the combined action of many kinds of microorganisms, among which the role of fungi is the most important. For example, the high-throughput sequencing of fungi involved in our research was conducted, though the results were not published; _Penicillium_ sp. and _Fusarium_ sp. were the most predominant fungi. A rising number of studies on the bacterial degradation of lignin have proved that bacteria can degrade lignin in a liquid matrix and, at the same time, have a good ability to adapt and regulate the environment [34]. Bacteria degrade lignin in the primary metabolic stage and synthesize lignin-degrading enzymes in the logarithmic and stable growth stages [35]. In the degradation process, bacteria mainly denaturate lignin to a certain extent and make it a water-soluble polymer, but they seldom mineralize lignin into CO\({}_{2}\). In addition, bacteria mainly play an indirect role in the degradation of lignin, and there are synergistic effects between bacteria and fungi in the degradation of lignin [36]. For waterlogged wooden artifacts, we suggest that some effective measures can be taken to conserve them. Most wooden remains from archaeological sites in waterlogged burial environments are found to be intact without shrinkage, despite centuries of storage. However, waterlogged wooden remains are subject to shrinkage damage, and some even lose up to 80% of their original volume when exposed to air [37]. When such objects are allowed to dry, they may collapse [38]. This is the reason why lacquer plates excavated from the Nanhai No. 1 shipw neck need to be conserved in water prior to reinforcement. Hence, it has been feasible to store the lacquer plates in sterilized distilled water or double distilled water (ddH\({}_{2}\)O), providing an environment with few microorganisms. While in storage, the water should be replaced at regular intervals. Furthermore, cold, dark and near-anaerobic conditions result in slower degradation [38]. Since the lacquer plates from the Nanhai No. 1 shipw neck involved in this research still need to be stored in water, the measure of maintaining an anaerobic environment needs to be considered. Meanwhile, other waterlogged wooden artifacts may take this method into account. In addition, the temperature used for wooden storage should be taken into consideration--waterlogged wood should be preserved at a low temperature of approximately 4 \({}^{\circ}\)C to inhibit bacterial growth.