Experimental Study on the Phlogopite Weathering Potential of Bacterial Communities Isolated from Different Soil Profiles

The silicate mineral weathering potential of different weathering pattern soil bacteria was characterized, and links between key habitat determinants and soil bacteria strategies were established in this work. Phlogopite weathering experiments were conducted under aerobic conditions and in closed systems with bacterial communities isolated from different soil profiles that are typical of a temperate climate. Our results suggest that the phlogopite weathering processes (i.e., acidolysis and complexolysis processes) of bacterial communities is determined by soil horizons as a function of (i) organic matter content, (ii) impoverishment in clays in leached horizons and (iii) the content of exchangeable cations. In our experiments, bacterial communities developed two strategies for iron release from phlogopite: the first was the K-strategy, which is used by bacterial communities extracted from soil rich in nutrient elements (especially in horizons with high contents of exchangeable Mg, Ca, etc.) and organic carbon. These communities produced strong chelating organic acids in low concentrations and used small amounts of carbon. The other was the r-strategy for bacterial communities extracted from soils poor in nutrient elements and organic carbon content. They produced weak chelating organic acids in large amounts and used a large proportion of the carbon source.