Characterization of a biofilm and the pattern outlined by its growth on a granite-built cloister in the Monastery of San Martiño Pinario (Santiago de Compostela, NW Spain)

New oxidative alginate-biocide hydrogels against stone biodeterioration

The potentially biodeteriogenic, subaerial green alga Trentepohlia umbrina is widely distributed on shaded substrates with northern aspects. This preference for low light was confirmed by a recent ...

Photosynthetic response to different light exposures and associated environmental conditions of the subaerial, epilithic green alga Trentepohlia umbrina (Chlorophyta, Ulvophyceae)

Abstract Pigment-based color is one of the most important phenotypic traits of biofilms at the mineral–air interface (subaerial biofilms, SABs), because it reflects the physiology of the microbial community. Because color is the hallmark of all SABs, we argue that pigment-based color could convey the mechanisms that drive microbial adaptation and coexistence across different terrestrial environments and link phenotypic traits to community fitness and ecological dynamics. Within this framework, we present the most relevant microbial pigments at the mineral–air interface and discuss some of the evolutionary landscapes that necessitate pigments as adaptive strategies for resource allocation and survivability. We report several pigment features that reflect SAB communities’ structure and function, as well as pigment ecology in the context of microbial life-history strategies and coexistence theory. Finally, we conclude the study of pigment-based ecology by presenting its potential application and some of the key challenges in the research.

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

The influence of environment and carbonation of fiber cement tiles on the reflectance of a cool surface exposed in four Brazilian cities

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. 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 (Kutzing) 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. The findings better define the ecological range of this species, suggesting a wider biogeographic distribution, and adding information on morphological features and genetic data.

/pdf/ecological-and-taxonomic-characterisation-of-trentepohlia-2l3c5o18d3.pdf

Lorenza Rugnini

Papers

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