Seasonal dynamics of airborne fungi in different caves of the Mogao Grottoes, Dunhuang, China Wanfu Wang a, b, 1 , Xu Ma a,1 , Yantian Ma a , Lin Mao a , Fasi Wu a, b , Xiaojun Ma a , Lizhe An a, * , Huyuan Feng a, * a School of Life Sciences, Key Lab of Arid and Grassland Ecology of Ministry of Education, Lanzhou University, Lanzhou, Gansu 730000, China b The Conservation Research Institute of Dunhuang Academy, Dunhuang 736200, China article info Article history: Received 17 March 2010 Received in revised form 13 May 2010 Accepted 17 May 2010 Available online 2 July 2010 Keywords: Aerobiology Biodeterioration Culturable fungi Mogao Grottoes abstract Fungal spores are ubiquitous and can be found in both outdoor and indoor air samples, we investigated 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 grand mean of total culturable fungi was 187.45  37.76 colony-forming units (CFU)/m 3 for all sites considered, and the number was 110.52  17.40 CFU/m 3 , 137.81  26.67 CFU/m 3 , 245.39  37.20 CFU/m 3 , 240.87  54.91 CFU/ m 3 in OC, SC, CC, OD. The most prevalent fungi were Cladosporium spp., non-sporing fungi, 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 fungal genus had significant seasonal variations, higher levels were observed in summer and autumn. Pearson correlation analysis showed that the levels of ambient fungi were correlated positively with temperature and visitor numbers, but negatively with relative humidity and rainfall. The results suggested that the visitors have an obvious influence on concentrations and compositions of ambient fungi in Mogao Grottoes providing information to be considered in conservation and management. Ó 2010 Elsevier Ltd. All rights reserved. 1. Introduction Many microorganisms such as fungi, algae and bacteria may have a negative effect on the preservation of artistic-historical heritage, especially when microclimatic conditions favor their growth. Recent studies reported interaction between microscopic fungi and arthropods on the surface of wall paintings leading to mural biodeterioration (Hoffland et al., 2004; Dupont et al., 2007; Jurado et al., 2008, 2009). These biological agents affect not only the aesthetical appearance but also the integrity of materials (Mitchell and Gu, 2000; Gu, 2003; Li et al., 2008; McNamara et al., 2010). Among all cave microorganisms, fungi are by far the most predominating due to their high rate of spore dissemination, better survival in the air and colonization capability. Therefore, many studies have been carried out on the mycobiota in conservation of heritage buildings (Jurado et al., 2009). 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. Fungal dynamics often shows a pronounced seasonal periodicity and fluc- tuations related to meteorological conditions such as solar radiation, temperature, rainfall and wind speeds, among others (Jones and Harrison, 2004). Constituents of indoor air can also be resulted from both outdoor and indoor sources from human or animal transportation. Normal indoor and enclosed conditions provide a suitable environment for the growth of a wide range of fungal spores (Gu, 2007). The presence of moisture or higher relative humidity is a prerequisite for the germination and growth of fungal spores. Some of these fungi can be allergic or toxic, while a few may cause infections in susceptible individuals (Green et al., 2005). The presence and concentration of airborne fungal spores, in both indoor and outdoor environments, have been the subject of numerous studies in various geographical regions (Basilico et al., 2007; Wu et al., 2007; Abdel Hameed et al., 2009; Stepalska and Wo1ek, 2009). More recently, airborne fungal spores have been investigated with reference to the conservation of art works * Corresponding authors. Tel.: þ86 931 8912560; fax: þ86 931 8912562. E-mail addresses: lizhean@lzu.edu.cn (L. An), fenghy@lzu.edu.cn (H. Feng). 1 Contribution equally to this work. Contents lists available at ScienceDirect International Biodeterioration & Biodegradation journal homepage: www.elsevier.com/locate/ibiod 0964-8305/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.ibiod.2010.05.005 International Biodeterioration & Biodegradation 64 (2010) 461e466