A Study of the Microbial Community at the Interface between Granite Bedrock and Soil Using a Culture-Independent and Culture-Dependent Approach

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-proteobacteria. Bacteria belonging to the genera Serratia, Pseudomonas, Bacillus, Paenibacillus, Chromobacterium 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 biogeo-* Corresponding author. K. Olsson-Francis et al. 234chemical cycle.

Geochemical bio-signatures in Martian analogue basaltic environments using laboratory experiments and thermochemical modelling

“…Unfortunately, the heterogeneity of the natural environment, the lack of control over changes during even a short sampling period, and the difficulty of finding relevant abiotic controls, make such work challenging. Moreover, although basalt weathering and secondary alteration mineral formation have been widely investigated in the field and in laboratory experiments under abiotic (Gislason and Eugster, 1987;Oelkers and Gislason, 2001;Wolff-Boenisch et al, 2006) and biotic conditions (Wu et al, 2007;Olsson-Francis et al, 2010;Olsson-Francis et al, 2012;Olsson-Francis et al, 2015;Olsson-Francis et al, 2016;Olsson-Francis et al, 2017;Price et al, 2018;Olsson-Francis et al, 2020) these studies have been only over short timeframes (months-years). This makes it difficult, if not impossible, to predict what would happen over years or even over geological time scales when the rock is fully dissolved or more likely, subject to the effects of incongruent dissolution.…”

Effects of Mineral on Taxonomic and Functional Structures of Microbial Community in Tengchong Hot Springs via in-situ cultivation

“…For example, mineral microhabitats (mica, basalt, and rock phosphate) contained nutritive elements such as P, K, Na, and Mg, which have been shown to determine and select bacterial communities with distinct structures [ 61 ]. At the same time, mineral weatherability has a prominent impact on microbial communities and can stimulate the growth of effective-weathering bacteria (e.g., β-Proteobacteria) on their surface [ 58 , 59 , 62 , 63 ]. Proteobacteria and Bacteroidetes , as the dominant bacterial phyla in terrestrial and aquatic habitats, are positively related to organic matter [ 64 ] and have been detected on minerals [ 58 , 59 , 65 ].…”

Effect of inorganic nutrients on bacterial community composition in oil-bearing sandstones from the subsurface strata of an onshore oil reservoir and its potential use in Microbial Enhanced Oil Recovery

“…(2010) observed that rocks with porosity of about 20% supported recovery of additional incremental oil from the sandstone core up to 75% [27]. The cores contained elements commonly found in other sandstone reservoirs’ strata [28]. Moreover, the produced water, which was low in salinity and had neutral to slightly alkaline pH, could support microbial growth [5].…”