Effect of organic forms of phosphorus and variable concentrations of sulfide on the metabolic generation of soluble-reactive phosphate by sulfur chemolithoautotrophs: a laboratory study

In aquatic systems, recycling of phosphorus (P) is strongly influenced by microbial metabolic responses. This study was designed to look at the generation of P (as soluble-reactive phosphate (SRP)) from organic P-enriched sediments by benthic sulfur chemolithoautotrophs. The study revealed that microbial density was greater in organic P-enriched sediments when compared to sediments without added organic P and the presence of organic P significantly influenced mobilization of SRP from sediment. Generation of SRP by sediment microbes was cumulative, dependent on time. The results indicated dissolved sulfide (S(2-)) to be necessary for initiation of the metabolism-related mobilization of P: there was no statistically significant effect of variations in ambient concentrations of sulfide (S(2-)). The results elucidate possible outcomes of addition of organic P in aquatic ecosystems.