Keywords: phosphorus solubilising bacteria, phosphate cycling, water eutrophication, water–sediment interface, environmental pollution, water pollution, biogeochemical function, simulation, water reservoirs, biofilm, metal ions, calcium, magnesium, iron
Biogeochemical function of phosphorus–solubilising bacteria on cycling of phosphorus at the water–sediment interface under laboratorial simulated conditions
With an efficient phosphorus–solubilising bacterium (PSB) Paenibacillus sp. isolated from sediment of a eutrophic water reservoir, the biogeochemical function of bacteria on the P–cycling at water–sediment interface was studied using simulated columns at laboratorial scale. Results showed that, when PSB formed biofilm at water–sediment interface, the P content showed a largest reduction of 56 mg/L in the water phase and of about 40–50 mg/L in the pore water of the sediment comparing to blank columns without PSB. The activity of alkaline phosphatase in the water phase increased as the bacterial biomass increasing when the P content is low. Great changes of Mg2+, Ca2+ and Fe2+ contents in the upper water phase and the pore water of sediment was observed when pH value increased from 7.5 to 8.5 at the interface mediated by the PSB, and had the similar trend of that of the P content. Results suggested that PSB could accelerate release of P from sediment, and the biogeochemical function of PSB on P–cycling between water phase and sediment relied on pH conditions of the upper water phase and the interfacial pore water, and influenced the concentration of metal ions, mainly as Mg2+ and Ca2+.