Bacterial Communities on the Surface of the Mineral Sandy Soil from the Desert of Maine (USA)

The Desert of Maine, not a real desert, is a 160,000 m2 tourist attraction of glacial silt which resembles a desert, surrounded by a pine forest in the state of Maine located in the northeastern USA. Though not a true desert, the soil of the Desert of Maine has a sandy texture with poor water-holding abilities, nutrient retention capabilities, and a relatively low pH value (pH 5.09). Samples from this site may be of interest to examine the bacterial diversity present on mineral sandy loam soils with an acidic pH, low concentrations of organic materials though surrounded by a pine forest, and compare it with true desert soil microbial populations. Two surface sand samples from the Desert of Maine were obtained, and pyrosequencing of PCR amplified 16S rRNA genes from total extracted DNA was used to assess bacterial diversity, community structure, and the relative abundance of major bacterial taxa. We found that the soil samples from the Desert of Maine displayed high levels of bacterial diversity, with a predominance of members belonging to the Proteobacteria and Actinobacteria phyla. Bacteria from the most abundant genus, Acidiphilium, represent 12.5% of the total 16S rDNA sequences. In total, 1394 OTUs were observed in the two samples, with 668 OTUs being observed in both samples. By comparing Desert of Maine bacterial populations with studies on similar soil environments, we found that the samples contained less Acidobacteria than soils from acid soil forests, and less Firmicutes plus more Proteobacteria than oligotrophic desert soils. Interestingly, our samples were found to be highly similar in their composition to an oak forest soil in France.