Ecological and taxonomic characterisation of Trentepohlia umbrina (Kützing) Bornet growing on stone surfaces in Lazio (Italy)

Abstract

Purpose The colonisation of building material by photosynthetic organisms is highly dependent on the environmental conditions and the nature of the substrate. The growths of red-orange phototrophic biofilms have been widely reported in the literature and have commonly been associated with the order Trentepohliales, whose ecological and taxonomical information needs to be improved. Considering the recurrent presence of such biofilms throughout the Lazio region, we would identify the occurring species and define their favourable environmental conditions, through morphological, genetic and ecological analyses. Results Biofilms were collected across an altitude range of 0 to 860 m asl, occurring from the coast to 60-km inland. A dominant presence of the filamentous terrestrial green alga Trentepohlia umbrina (Kützing) Bornet was confirmed in all sites sometimes mixed with cyanobacteria of the genus Gloeocapsa. The distribution of Trentepohliales is generally given as pan-tropical, but some species, such as T. umbrina, are also distributed in temperate climates. Here, it is reported for the first time a Mediterranean occurrence of the species. Low humidity and light conditions, such as those occurring on vertical surfaces with mainly northern aspects, are the preferred environmental conditions. Coastal areas were more favourable for its growth, probably due to the higher nocturnal condensation that occurs here. Concrete and mortars were particularly bioreceptive to T. umbrina, but marble and trachyte were also colonised under favourable conditions. Conclusions The findings better define the ecological range of this species, suggesting a wider biogeographic distribution, and adding information on morphological features and genetic data.

Predicted Dynamic of Biodeterioration in Cultural Heritage Stones Due to Climate Changes in Humid Tropical Regions—A Case Study on the Rhodotorula sp. Yeast

“…Typical examples of metabolites are carotenoids, natural pigments that are part of the class of tetraterpernoid compounds derived from highly unsaturated isoprenes. These bioactive compounds, which may induce yellow, orange, pink, and red hues [36], are mostly produced by filamentous fungi and yeasts, but also bacteria, algae, and lichens [37]. Their main functions are the harvesting of light energy, protection against oxidative damage, and stabilization of certain pigment-protein complexes.…”

In Living Color: Pigment-Based Microbial Ecology At the Mineral–Air Interface

“…Within biodeterioration processes, a rosy alteration is a widespread phenomenon on both lithic and painted surfaces. The phenomenon was related mainly to the presence of cyanobacteria (Cappitelli et al 2009 ) and algae (Ortega-Morales et al 2013 , Bartoli et al 2019 ) and extremophiles (alkaliphilic, thermophilic, and halophilic microorganisms) that produce carotenoids (Imperi et al 2007 , De Felice et al 2010 , Ettenauer et al 2014 , Gomoiu et al 2017 , Cojoc et al 2019 , Leplat et al 2019 ). The common link among different monuments colonized by pink biofilms (due to carotenoids) seems to be the crystallization of salts aided by water infiltration, which creates an optimal condition for the growth of the halophilic microorganisms (Ettenauer et al 2014 ).…”

The Green Patina and Chromatic Alterations on Surfaces of Gypsum Plaster Casts by Lucio Fontana: Multidisciplinary Investigations in a Case Study of Contemporary Art

“…In fact, microbial colonization of heritage materials can lead to discolorations, sometimes disfiguring the surface. Fungi-tape sampling is a non-invasive technique, widely used for monitoring microbial colonization on different materials, from human skin infections [23] to objects with cultural value like bones [24] to stone surfaces [25]. Figure 3 Bright field microscope images display filamentous structures of dust with a blue fluorescence probably due to the presence of cellulose.…”