The maximum total heterotrophic bacteria (THB.2.92 x 10⁴ CFU/ml) and phosphobacteria (PB1.69 X 10⁴ CFU/ml) in water and in sediment (rHB-3.57 x 10⁴ CFU/g; PB-2.42 x 10⁴ CFU/g) were recorded respectively during July 1985, Similarly higher concentrations of adsorbed phosphate in sediment (43 µg PO₄-P/g) and soluble phosphate in water (16µg PO₄-P/1) were noticed during the same month. The phosphate content positively influenced the distribution of both THB and PB and inversely related to the salinity and the minimum salinity (20% J was observed during July 1985. 188 strains of phosphobacteria were identified to the generic level (Pseudomonas, Vibrio, Moraxella, Bacillus, Micrococcus and Corynebacterium). Of these Pseudomonas predominated both in sediment (45%) and in water (34.8%). Since the phosphate is essential for the productivity of phytoplankters, two potent strains such as Pseudomonas and Vibrio were selected for the study of the influence of incubation period, carbon sources and the temperature for the maximum release of phosphate from the tricalcium-phosphate and for their optimum growth. Both the isolates released maximum phosphate within 72 hrs. and 0.1% of glucose enhanced the maximum release of phosphate. Pseudomonas solubilized maximum phosphate and obtained optimum growth at 37°C whereas in Vibrio they were at 29°C. It is understood that bacteria could also be utilised for the leaching of the low grade ore samples and of the three types of ore samples used Pseudomonas leached out 0.700 mg/g of phosphate from the sedimentary ore. These observations suggest that the microorganisms play an important role in the metabolism of phosphorus and the removable of impurities from the low grade ore samples