Distribution of phosphate-accumulating bacteria in phosphorite-bearing rocks and surface and ground waters of the Ural region

Phosphate-accumulating bacteria (PAB) were quantified in phosphorite-bearin g rocks and surface and ground waters of various origin in a number of regi ons of Perm, Chelyabinsk, and Kirov oblasts. The number of PAB was very low in springs in winter, prior to ground melting (0.01% of the total bacteria l number of 0.1 million cells/ml). Elevated numbers of PAB were found in gr ound waters of Kungurskaya ice cave (18-41% of the total bacterial number o f 0.2-8.3 million cells/ml), in near-bottom waters of Nytvenskoe and Ochers koe reservoirs (23-56% of 17-438 million cells/ml), and in moist loose frac tions of sedimentary racks of the Ashanskoe and Vyatsko-Kamskoe phosphorite deposits (26-52% of 1.2-37 billion cells/g). The absolute and relative con tents of volutin-containing cells tended to increase with the increase in t he total number of bacteria in poorly aerated neutral and alkaline environm ents with pH 7.1-9.4; this was accompanied by the formation of precipitable phosphorus- and iron-containing bacterial aggregated, a decrease in the sp ecific rate of heterotrophic carbon dioxide fixation in situ, and loss of t he ability to grow on rich nutrient media by a large portion of the bacteri al population.