ABSTRACT
The dissolution of minerals plays an important role
in the formation of soils and sediments. In nutrient limiting soils, minerals constitute a
major reservoir of bio-essential cations. Of particular interest is granite as
it is the major rock type of the continental land mass. Although certain bacteria
have been shown to enhance weathering of granite-forming minerals, little is
known about the dissolution of granite, at the whole rock scale, and the
microbial community involved. In this study, both
culture-independent and culture-dependent approaches were used to study the
bacterial community at the interface between granite bedrock and
nutrient limiting soil in Dartmoor National Park, United Kingdom. High throughput sequencing
demonstrated that over 70% of the bacterial population consisted of the
bacterial classes Bacilli, Beta-proteobacteria and Gamma-proteo-bacteria. Bacteria
belonging to the genera Serratia, Pseudomonas, Bacillus, Paenibacillus, Chromo-bacterium and Burkholderia were isolated from the
sample site. All of the isolates were able to grow in a minimal growth medium,
which contained glucose and ammonium chloride, with granite as the sole source
of bio-essential elements. Sixty six percent of the isolates significantly enhanced
basalt dissolution (p < 0.05). Dissolution
of Si, K, Ca and Mg correlated with production of oxalic acid and
acidification. The results of this study suggest that microorganisms in
nutrient limiting soils can enhance the rate of granite dissolution, which is
an important part of the biogeochemical cycle.
Share and Cite:
Olsson-Francis, K. , Pearson, V. , Schofield, P. , Oliver, A. and Summers, S. (2016) A Study of the Microbial Community at the Interface between Granite Bedrock and Soil Using a Culture-Independent and Culture-Dependent Approach.
Advances in Microbiology,
6, 233-245. doi:
10.4236/aim.2016.63023.