A Lichens-Mediated Mechanism for Environmental Biodeterioration

Abstract

As mediators in soil formation, lichens play an essential role in the physical and biological formation of the natural environment. A recent study showed that they are capable of biodegrading stone substrates in a little amount of time, despite being excluded in a geological setting. Many species, mainly those able to produce an oxalate at the thallus-substratum interface, can alter the surface, affecting it chemically. The oxalate remains a noticeable increase even after the lichen has faded, and it makes a major contribution to the structure and composition of the thallus itself. These severe oxalate deposits on historical sites have been alternatively attributed to the earlier as the consequence of air pollutants, prior mechanical/chemical renovation treatments, as well as environmental deterioration. Lichen growth on building materials and biodegradation are frequently based on environmental variables. The biogeophysical and biogeochemical weathering of the substrate by the lichens is the mechanism underlying biodegradation. For stone surfaces, lichens can endeavor bio protection by acting as a barrier against weathering, holding humidity, improving permeability, reducing heat stress and erosion, and absorbing contaminants. Lichen’s significance as a biodeteriorant, its colonization and impact on monuments, as well as bioprotection, are all discussed in the current review.