Environmental Factors Affecting the Diversity and Abundance of Soil Photomicrobes in Arid Lands of Subtropical Taiwan

The purpose of this study was to characterize the diversity and abundance of indigenous soil photomicrobes with respect to the physico-chemical environment at a highly eroded loamy sand mountain situated in mid-Taiwan. Denaturing gradient gel electrophoresis and clone library were employed to characterize the operational taxonomic unit of photomicrobes present in the natural environment. The predominant species identified by plastid 23S rRNA were green algae belonging to the genera Bracteacoccus, Coccomyxa, and Koliella, while sub-dominant species included the cyanobacteria Leptolyngbya and Microcoleus. Principal component analysis indicated that the distribution of soil photomicrobes exhibited a strong dependency on the chemical variables, such as organic materials, total nitrogen, and inorganic nutrients, and that the low diversity was related to low water potential status. The present study illustrated the main factors affecting the distribution of soil photomicrobes and provided the basic characteristics of biological soil crusts in arid lands in subtropical areas.