Biopatinas: Cryptogams in urban environment as potential biofilters, CO2 sinks, and bioremediation systems

Biopatina refers to cryptogamic organisms that naturally thrive on urban architectural surfaces, such as buildings, stone walls, and monuments, often influencing the surface coloration and structure. Similar to other cryptogams that thrive in natural environments, biopatinas represent photosynthetic communities composed of various organisms that serve numerous ecosystem functions. Here, we hypothesize that biopatinas can provide a microclimatic cooling effect, serve as a valuable carbon sink, and function as natural biofilters by trapping particulate matter and dust. Additionally, we suggest that they may act as a bioremediation system for breaking down polycyclic aromatic hydrocarbons (PAHs). Our hypothesis will be investigated on representative biopatinas on building surfaces in the city of Vienna in the framework of our project “Biopatinas on buildings in urban environments” funded by WWTF (Wiener Wissenschafts-, Forschungs- und Technologiefonds). We will collect biopatina as well as uncolonized samples from randomly selected buildings during two different seasons (e.g., summer and winter). On these samples, we will conduct CO₂ gas exchange measurements to assess the carbon fixation and measure the dust entrapment properties of wet and dry biopatina. Furthermore, the role of biopatina in regulating surface temperature of building walls will be examined under varying hydration conditions. Since the function of biopatina is related to its microbial composition, we will characterize its composition by means of metagenomics. We will map the biopatina coverage in a representative part of Vienna to be used for upscaling in order to develop predictive models.

In this highly interdisciplinary project, the scientific approach will be supported by the use of participatory art-based practices to achieve greater public awareness and acceptance of biopatina on monuments and architecture in the city. The results of our study will help to embrace the functional complexity of biopatina, which will be essential for protecting cultural heritage, increasing urban environmental quality, and developing biologically informed solutions for sustainable cities.