Impact of Environmental Factors on the Formation and Development of Biological Soil Crusts in Lime Concrete Materials of Building Facades

Microbial colonization leads to the formation of biological soil crusts (BSCs) on the surface of architecture, which causes the deterioration of construction materials. However, little information is available on the formation of BSCs on lime concrete materials of early architecture. In this study, the variances of microbial communities, physicochemical properties, and surrounding environmental factors of the lime concrete facades from the early architecture of Wuhan University were investigated. It was found that the surface of lime concrete materials was internally porous and permeable, embedded with biofilms of cyanobacteria, mosses, bacteria, and fungi. Redundancy analysis (RDA) analysis showed that the abundances of photoautotrophic microorganisms depended on light intensity and moisture content of construction materials, while that of heterotrophic microorganisms depended on total nitrogen (TN) and NO3−-N content. The deposition of total carbon (TC), NH4+-N, and total organic carbon (TOC) was mainly generated by photoautotrophic microorganisms. The lime concrete surface of early architecture allowed internal growth of microorganisms and excretion of metabolites, which promoted the biodeterioration of lime concrete materials.