Bacterial community composition of divergent soil habitats in a polar desert

Abstract

Edaphic factors such as pH, organic matter, and salinity are often the most significant drivers of diversity patterns in soil bacterial communities. Desert ecosystems in particular are model locations for examining such relationships as food web complexity is low and the soil environment is biogeochemically heterogeneous. Here, we present the findings from a 16S rRNA gene sequencing approach used to observe the differences in diversity and community composition among three divergent soil habitats of the McMurdo Dry Valleys, Antarctica. Results show that alpha diversity is significantly lowered in high pH soils, which contain higher proportions of the phyla Acidobacteria and Actinobacteria, while mesic soils with higher soil organic carbon (and ammonium) content contain high proportions of Nitrospira, a nitrite-oxidizing bacteria. Taxonomic community resolution also had a significant impact on our conclusions, as pH was the primary predictor of phylum-level diversity, while moisture was the most significant predictor of diversity at the genus level. Predictive power also increased with increasing taxonomic resolution, suggesting a potential increase in niche-based drivers of bacterial community composition at such levels.

The role of abiotic factors modulating the plant-microbe-soil interactions: toward sustainable agriculture. A review

“…Furthermore, pH was recently proposed to be the best predictor of microbial diversity at the phylum level (Geyer et al, 2014), which is consistent with a recent study of the presence of Acidobacteria along an elevational gradient (Zhang et al, 2014). Acidobacteria is one of the most dominant soil genera, which could reflect its metabolic plasticity.…”

“…In an analysis of soil bacteria diversity, Zhang et al (2013) found that Proteobacteria was the dominant group and was significantly associated with the amount of soil moisture. Geyer et al (2014) investigated the association between the type of soil and bacterial diversity in Polar desert soils, and also found that moisture content was closely related to the abundance of several bacterial genera.…”

Genomic profiling of four cultivated Candidatus Nitrotoga spp. predicts broad metabolic potential and environmental distribution

“…Nitrospira are the only known thermophilic NOB; whereas, Ca. Nitrotoga, Nitrospina, and Nitrospira have been detected in polar settings [104][105][106]. Overall, Ca.…”

Unimodal productivity–diversity relationships among bacterial communities in a simple polar soil ecosystem

“…Model soils help to establish causative relationships that may be obscured in other systems by confounding variables. Our earlier work from this system documented an asymptote in bacterial diversity along a naturally occurring soil productivity gradient (Geyer et al ., ; Geyer et al ., ). The objectives of the present study are to (i) confirm earlier observations with a manipulative experiment and (ii) induce a broader resource gradient than natural field conditions provide in order to capture the full potential response profile of bacterial diversity.…”