Microbial Ecology of Indoor Environments: The Ecological and Applied Aspects of Microbial Contamination in Archives, Libraries and Conservation Environments

Abstract

Filamentous fungi can colonise a wide range of organic and inorganic materials and play an important role in biodeterioration processes. They are able to tolerate desiccation, high mineral salt concentrations and the heavy metal compounds that are often present in inks and pigments, substances which are therefore frequently found on paper supported heritage and in the dust present in closed spaces. The fungal and bacterial communities that can develop on a book are similar to the communities of decomposers which, in natu-ral environments, transform nutrients bound to lifeless organic mat-ter into low molecular or inorganic forms, thereby making them available to plants. The development and sustained presence of a fungal community on a shelf in a library or on an individual book depends on the type of spore that reaches the host material's surface, the particular microenvironment (temperature, relative humidity, light), the substrate's water activity, and the casual events which promote the colonisation of materials (insect-bourne dispersion, hu-man contamination, external sources of fungal diversity). An entire library or a single book can be compared to a tract of virgin land reached by colonising organisms which then behave like a pioneer-ing species on fresh soil. According to Wardle (2002) species' iden-tity and the composition of decomposers exert a far greater impact on ecosystem processes than species richness per se. When consider-ing paper stored in a closed environment, its colonisation and bio-degradation depends on species identity and composition since only cellulolytic organisms can exploit the bulk of the substrate (Pinzari