岩画和壁画类文物微生物病害研究进展

古代岩画和壁画是人类文明发展历史进程的重要记录,具有极高的历史价值、艺术价值及科学价值,但他们无时无刻不受到环境因素引起的物理、化学及生物的劣化作用。近年,有关微生物对古代岩/壁画的危害逐渐受到关注。阐述了世界一些著名的岩/壁画文物的微生物的研究进展,如法国拉斯科洞穴岩画(Lascaux Cave)、西班牙阿尔塔米拉洞穴岩画(Altamira Cave)、敦煌石窟壁画、嘉峪关魏晋墓壁画以及我国东北地区公元5世纪的墓葬壁画等。通过对以上所述岩画和壁画微生物群落的分析比较,发现主要的细菌群落是变形菌门和放线菌门,放线菌门以假诺卡氏菌为主。真菌群落主要以虫生真菌为主。进一步分析了岩画和壁画微生物病害的共性和区别,揭示了洞穴、墓室等特殊环境下的微生物群落特点,为防治古代岩/壁画微生物病害提供了以下借鉴。

Microbial deterioration in ancient cave and wall paintings

Abstract: Ancient cave and wall paintings are important records of human civilization, with great historical, artistic and scientific value, however they are commonly affected by physical, chemical and biological deterioration. In recent years, the issue of microbial deterioration in ancient cave and wall paintings has received more attention. This paper summarizes the research progress on the effect of microbes on famous cave and wall paintings throughout the world, such as the Lascaux cave paintings (France), the Altamira cave paintings (Spain), the Dunhuang Mogao grottoes murals (China), the Wei and Jin dynasty tomb wall paintings (Jiayuguan, China), and the 5th century tomb murals from the northeast of China. Through a comparative study of microbial communities at these sites, we conclude that the microbes responsible for cave painting degradation are mainly Proteobacteria and Actinobacteria, of which Escherichia and Enterobacter are types of human pathogenic Proteobacteria. According to the analysis in this review, the emergence of these microbial communities in cave and wall paintings is closely related to the presence of tourists. The acid metabolism produced by Pseudonomas and Nitrobacter causes serious corrosion of murals. Our results suggest that the Actinobacteria Pseudonocadia accounts for approximately 68% of bacteria in a clone library produced from samples taken from 5th Century tomb murals in northeast China. Pseudonocadia is the dominant microflora responsible for white biofilms attached to the murals, while algae are the dominant flora responsible for the green biofilms, the abundance of which is closely related to light, carbon dioxide and humidity levels in the cave. Conversely, fungal communities on cave murals, dominated by entomogenous fungi, appear to have a close relationship with insects that live in the cave. This paper analyzed similarities and differences between microbial communities that do harm to famous ancient cave and wall paintings, in an effort to understand their characteristics under the specific conditions found in caves and tombs, and also provide useful information for ancient painting conservation. Firstly, if effective measures are to be taken to protect these world heritage sites, it is important to consider the ecological perspective. Microorganisms do not grow in isolation and the relationship between various microorganisms, between microorganisms and the environment, and between microorganisms and insects, should be considered in order to facilitate the protection process. For example, a change in cave temperature and humidity will prevent a proportion of the microflora from growing due to the newly unsuitable conditions. Secondly, adopting a cross-disciplinary approach incorporating physics, chemistry, biology and engineering science, will help to control the emergence of these damaging microfloral communities. Furthermore, employing the methodology of phage inhibition and competitive advantage to inhibit the growth of unwanted microbial communities has proven to be an important research direction in recent years. Thirdly, both the conservation and tourist requirements of these cave sites must be balanced in the long-term, for example by reducing the number of visitors that enter the caves and tombs, and by employing the use of disposable sterile clothing and shoe covers to reduce the transmission of exogenous microbes into the caves. The long-term monitoring and regular analysis of cave and tomb paintings and the balancing of the local ecosystem are both important directions for the protection of these cultural heritage sites.