Core bacterial community composition of a cryptoendolithic ecosystem in the Grand Staircase‐Escalante National Monument, Utah

Cryptoendolithic bacterial communities in the Jurassic Navajo Sandstones play an important ecological role in this ecosystem. Developing a better understanding of the role of these cryptoendolithic communities required a deeper knowledge of the microbial diversity present. We analyzed the bacterial diversity in eight sandstones samples from several microgeological features associated with a large sandstone dome. Cryptoendolithic bacterial diversity is clustered into three distinct groups which correlated with topography, suggesting the duration of water retention might be a factor. Comparisons of diversity between each cluster showed that a core bacterial community exists in this habitat. The overall bacterial community structure was dominated by Cyanobacteria , Proteobacteria , Bacteroidetes, and Actinobacteria . The most prevalent genera in cyanobacteria were Leptolyngbya , Chroococcidiopsis, and unclassified cyanobacteria accounting for the bulk of cyanobacterial sequences. Within the Proteobacteria , Alphaproteobacteria were the largest class detected, with members of the Acetobacteraceae, particularly the genus Acidiphilium , being the most abundant. Acidiphilium spp. are capable of aerobic ferric iron reduction under moderately acidic conditions, explaining the high levels of iron ( II ) in this system. This study highlights the extent of unexplored bacterial diversity in this habitat system and sets the premise for elaborating on the ecological function of cryptoendolithic communities.