
Violeta Atienza and Isaac Garrido, professors in the Department of Botany and Geology at the University of Valencia, are investigating approximately twenty species of fungi that have appeared in archived documentation affected by the Mediterranean storm known as DANA of 29 October, which was relocated to Feria Valencia. Microscopic examination of the fungi's characteristics has identified species belonging to the genera Stachybotrys, Penicillium, Aspergillus and Cladosporium. These fungi form mould on the documents – particularly in shades of grey, white, black and greenish – and can continue biodegrading the paper and cardboard, as well as producing pigments that aesthetically alter the documents or erase information.
In addition to the microscopic study, which involves the morphological analysis of reproductive structures using staining techniques (lactophenol blue) and phase-contrast microscopy, Garrido and Atienza will also extract DNA from the various samples collected to conduct a phylogenetic study. Specifically, they will perform a PCR to amplify the so-called “fungal genetic barcode”, a region of 500 to 600 nucleotides used to infer fungal phylogenies.
“This strategy will not only refine the taxonomic identification of fungal species, but also measure intraspecific genetic diversity, considering samples from the different municipalities affected by the DANA. In fact, it is assumed that some of the species collected have never been recorded in the Valencian Community, based on current data in the Valencian Biodiversity Data Bank”, explain Atienza and Garrido.
The specialists indicate that if analysis of the samples reveals any fungal species previously associated with public health issues, the technical staff working on the restoration of the archives will be informed to enhance protective measures. “It is important to remember that these fungi disperse via very small spores, sometimes less than 10 micrometres in diameter, which can easily be carried by the wind. The spores themselves are not destructive, but under suitable conditions of humidity and substrate, they can germinate and develop mature mycelia, which produce enzymes that facilitate material degradation”, the researchers explain.
Atienza and Garrido have focused their work on paper documentation, including documents that in some cases are over a century old. These substrates, in conditions of high humidity, have proven to be an ideal habitat for numerous fungal species. At Feria Valencia, they have been working with technical staff from the Valencian Institute for Conservation and Restoration (IVCR+i).
From visual observation alone, they conclude that most towns host more or less the same species. However, there are exceptions, such as Aldaia, where due to the diversity of substrates, the weather or the degree of humidity the documents were exposed to, a greater variety of species seems to be present.
Annex photo captions:
- Examples of fungi, including species of the genera Aspergillus, Penicillium and Stachybotrys.
- Documents affected by the DANA in a pavilion at Feria Valencia, where researchers from the University of Valencia are working.