| Aerobiological investigations of cultural heritage may help to identify the presence of microorganisms and then is possible to intervene for the prevention of biological degradation of art works by controlling microbial growth and biofilm formation. Mogao grottoes are well-know due to its amazing sculptures and ancient wall paintings. But it suffered from factors like collapse, salts problems, lost of painting layers, sand blown by wind, and biological deterioration etc. With the increasing of tourists year by year, both environment outside and microclimate inside caves will be affected greatly, the mechanisms of mural diseases would be activated or aggravated. In order to monitor mural diseases and microenvironment in each cave, clarify the mechanisms and corresponding environmental factors, we selected the typical caves and its attached environment as our study objects, to investigate the composition and community structures of fungi exists in aerosols surrounding in Mogao Grottoes of Dunhuang, China. Meanwhile, we aimed to provide some helpful advice or guidance for the visitor management and conservation of ancient wall paintings.In our study, we used morphological method and molecular method to investigate the temporal and spatial distributions, compositions, and determinants of ambient airborne fungi in Mogao Grottoes of Dunhuang, China. Culturable fungi in three categories of caves, Open Cave (OC) to visitors, Semi-open Cave (SC), and Closed Cave (CC) and an outdoor area (OD) in Mogao Grottoes monthly from September 2008 to August 2009, using a six-stage Anderson FA-1 sampler.The results demonstrated that the grand mean of total culturable fungi was 187.45±37.76 colony-forming units (CFU)/m3 for all sites considered, the number was 110.52±17.40 CFU/m3, 137.81±26.67 CFU/m3,245.39±37.20 CFU/m3,240.87±54.91 CFU/m3 in OC, SC, CC and OD individually. The most prevalent fungi were Cladosporium spp., Fusarium spp., Penicillium spp., Alternaria spp. and Aspergillus spp. at all four sampling sites. Airborne fungal numbers and their diversity were generally higher in CC and OD than in OC and SC. Most of fungal genus had significant seasonal variations, more appeared in warmer seasons. Pearson correlation analysis indicated that the numbers of ambient fungi were correlated positively with temperature and visitor numbers, but negatively with relative humidity and rainfall in our study site. The community structure of culturable fungi varied greatly at four different sampling sites, demonstrated by the Principal Coordinate Analysis (PCoA). Significantly effects were found between community composition in genera level and sampling sites (r=-0.293, p=0.039), as well as sampling time (r=-0.523, p=0.000). The airborne fungi abundance and concentrations varied throughout the sampling time in four different sampling sites. Meteorological parameters influence both abundance and community structure of airborne fungi in Mogao Grottoes, Dunhuang. Meanwhile, visitor was also influenced concentrations and compositions of ambient fungi evidently in our study site. Temperature, Relative humidity and human activity are the main factors influencing fungal concentrations and community structure in Mogao Caves. High temperature, high humidity, and more visitors will increase the concentration and diversity of aerosol fungi, especially in bigger caves.The results suggested that temperature, relative humidity and human activity have an obvious influence on concentrations and compositions of ambient fungi in Mogao Grottoes and providing information to be considered in conservation and management of Mogao Grottoes...
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