1 research outputs found
Bacterial Communities Involved in Soil Formation and PlantEstablishment Triggered by Pyrite Bioweathering on ArcticMoraines
Abstract In arctic glacier moraines, bioweathering primed
by microbial iron oxidizers creates fertility gradients that
accelerate soil development and plant establishment. With
the aim of investigating the change of bacterial diversity in
a pyrite-weathered gradient, we analyzed the composition
of the bacterial communities involved in the process by
sequencing 16S rRNA gene libraries from different biological
soil crusts (BSC). Bacterial communities in three BSC
of different morphology, located within 1 m distance
downstream a pyritic conglomerate rock, were significantly
diverse. The glacier moraine surrounding the weathered site
showed wide phylogenetic diversity and high evenness with
15 represented bacterial classes, dominated by Alphaproteobacteria
and pioneer Cyanobacteria colonizers. The bioweathered
area showed the lowest diversity indexes and only nine
bacterial families, largely dominated by Acidobacteriaceae
and Acetobacteraceae typical of acidic environments, in
accordance with the low pH of the BSC. In the weathered
BSC, iron-oxidizing bacteria were cultivated, with counts
decreasing along with the increase of distance from the rock,
and nutrient release from the rock was revealed by
environmental scanning electron microscopy-energy dispersive
X-ray analyses. The vegetated area showed the presence
of Actinomycetales, Verrucomicrobiales, Gemmatimonadales,
Burkholderiales, and Rhizobiales, denoting a bacterial
community typical of developed soils and indicating that the
lithoid substrate of the bare moraine was here subjected to an
accelerated colonization, driven by iron-oxidizing activity