Survival of Candida albicans and Pseudomonas aeruginosa in oil polluted tropical coastal waters

The effect of environmental abiotic factors on survival and activity of oil degrading isolates, Pseudomonas aeruginosa OD-1 and Candida albicans OD-2, was determined in situ using membrane diffusion chambers. The study sites were located in a tropical bay on the Atlantic Ocean with history of petroleum contamination by oil tankers. Microbial densities were measured by direct counts. 3H-thymidine uptake, microautoradiography, INT-reduction, adenosine triphosphate (ATP), and frequency of dividing cells were used to assess microbial activity. Both organisms showed a significant decrease in cell density over a three day period, although, temporal increases in densities were observed. Significant decreases in total activity were observed for both populations during the study; however, the respiration potential and ATP content per organism remained constant or even increased by the end of the study suggesting that a significant fraction of these populations were capable of withstanding in situ environmental conditions. Results suggest that increases in ambient phosphorus concentrations played a role in the prolonged in situ survival of these petroleum degrading isolates at some sites. The traffic of oil tankers might have played a significant impact on microbial survival in this bay, as violent agitation of sediments increased phosphorus concentrations available to microorganisms.