New microcolonial black fungus with potential to contribute to monument degradation was discovered.

Diana Paiva, researcher from the CFE from the Department of Life Sciences (DCV) from the Faculty of Sciences and Technology of the University of Coimbra (FCTUC), has identified and described a new genus and species of microcolonial black fungus with the potential to contribute to stone monument degradation.

With the name Saxispiralis lemnorum, this new species was found in Panteão dos Lemos, a National monument in Trofa do Vouga, Águeda, on a limestone funerary art piece with markers of biodegradation. This species belongs to the Aeminiaceae family which was discovered by the same research group, led by the DCV Professor António Portugal, in 2019, in Sé Velha, Coimbra. The name of this new genus alludes to the substrate where it was isolated, and to its peculiar morphological characteristics. While the specific epithet is a tribute to the monument in which it was identified.

Similar to the species Aeminium ludgeri, which was the only other species belonging to Aeminaceae family until this discovery, “the new species is also characterized by its impressive ability to survive adverse conditions. Black fungi are an ecological group of melanized fungi that are widely known as one of the main contributors to biodegradation of stone cultural patrimony” reveals Diana Paiva.

As is explained by the CFE researcher, “these fungi have notable adaptations that allow them to tolerate a wide range of stress factors, such as extreme temperatures, high ultraviolet radiation dosages, low availability of water and nutrients, high concentration of salt and pH fluctuations, that are frequently found in the surface of stone. By colonizing stone, these fungi can introduce chemical degradation by secreting a variety of compounds, such as siderophores for instance.

However, “the significant damage results from the mechanical action caused by its hyphae growth, which can lead to erosion, to small fissures formation and to the disaggregation of small stone fragments, consequently, weakening the substrate”, describes Diana Paiva.

According to the researcher, this finding should not be looked at as alarming. “The aim should not be to eradicate these types of fungi, and that is why studies like this one are so important, but to understand the best way to minimize the impact these fungi have and, consequently, protect these monuments” she says.

Given the incalculable value that these historic monuments have, according to Diana Paiva “doing studies like this one is crucial to build an information base about this and other species that colonize stone, that can be useful for the establishment of restoration processes more adequate and effective for the conservation of cultural patrimony, allowing to control these organisms’ development”.

This study, developed as a part of her Ph.D. in Biosciences, “represents a significant contribution to the understanding of fungi diversity that affects the deterioration of limestone patrimony”, believes Diana Paiva, also revealing that, in Panteão dos Lemos, a diversity much higher than initially expected was found. “We are working on the description of seven more species, which involves long and laborious work”, she concludes.

The paper published in the Jounal of Fungi can be accessed here.

(Original press release in Portuguese by Sara Machado, FCTUC)