Study on the Biological Communities and Bioweathering of Marble Surfaces at Temple of Heaven Park, Beijing, China

Abstract. This study examines the biological communities on the marble surfaces of the Temple of Heaven Park, Beijing, China and finds that the dominant populations are aerophytic cyanobacteria (blue-green algae) that prefer calcareous environments, are drought-resistant, slow-growing, and extremely resilient. These aerophytic cyanobacteria on the marble surface of the Hall of Prayer for Good Harvests in the Temple of Heaven exhibit different population compositions depending on the orientation. On the east-facing, warm and humid rock surfaces, the biological communities are mainly composed of small filamentous algae and spherical algae, such as Scytonema bohneri and Gomphosphaeria sp. On the west-facing, hot and humid rock surfaces, the biological communities are mainly composed of small filamentous algae and mosses, such as Scytonema millei. On the north-facing, cold and humid rock surfaces, the biological communities are mainly composed of spherical algae, such as Myxosarcina sp. and Gomphosphaeria sp. On the south-facing, hot and dry rock surfaces, the biological communities are mainly composed of small filamentous algae or large filamentous algae, such as Scytonema myochrous and Nostoc calcicole. The biological communities in the study area display various colors, with grayish-black being the most common, followed by grayish-white, black, brown, and blackish-brown. The grayish-black communities are primarily composed of Myxosarcina sp. and Gomphosphaeria sp. The rock surface biological communities exhibit different morphologies, including membranous, hairy, carpet-like, leathery, shell-like, and powdery layers. Different morphological communities have different population compositions. The growth and distribution of aerophytic organisms on the rock surfaces are closely related to the smoothness and texture of the marble. On uneven or non-uniform marble surfaces, aerophytic communities appear in spots, forming solution pits, cavities, and depressions. On surfaces with linear patterns or non-uniform textures with joint stripes, the communities form linear distributions, resulting in solution marks, grooves, and channels. On smooth, uniform marble surfaces, the communities spread evenly, leading to weathering layers or exfoliation. The mechanism of biological dissolution involves aerophytic organisms secreting organic acids, which dissolve inorganic salts from the rock to obtain nutrients. This process “erodes” the rock, damaging its surface structure and gradually weathering it. Given the prolific growth of aerophytic organisms on marble surfaces, finding ways to prevent or reduce their growth is crucial for slowing down the weathering process of stone cultural relics in the Temple of Heaven Park.