Phosphorus limitation determines the quality of dissolved organic matter released by marine heterotrophic prokaryotes

We determined phosphorus (P) limitation effect on the quantity and quality of dissolved organic matter (DOM) released by heterotrophic prokaryotes (HP). grew two single-bacterial strains from different lifestyles, copiotrophic Photobacterium angustum oligotrophic Sphingopyxis alaskensis, natural HP communities collected in fall spring Mediterranean Sea, glucose under treatments: P-replete versus P-limiting. DOM release comprised up to 30% initial carbon provided for growth. P-availability influenced allocation cellular processes (respiration vs. growth), but did not significantly affect net HP. However, using fluorescence spectroscopy, we demonstrated an P-limitation quality, with a predominance humic-like compounds protein-like P-repletion. Our results suggest that could determine fate HP-derived ocean, thus affecting microbial pump.