Is phosphorus limitation of planktonic heterotrophic bacteria and accumulation of degradable DOC a normal phenomenon in phosphorus-limited systems? A microcosm study

• Published in: FEMS microbiology ecology 2003-12, Vol.46 (3), p.307-316
• Main Authors: Vadstein, Olav, Olsen, Lasse M, Busch, Arild, Andersen, Tom, Reinertsen, Helge R
• Format: Article
• Language: English
• Subjects: Action of physical and chemical agents on bacteria; Alga; Animal, plant and microbial ecology; Bacteriology; Biological and medical sciences; Coexistence; Dissolved organic carbon; Fundamental and applied biological sciences. Psychology; Heterotrophic bacteria; Microbial ecology; Microbiology; Patchiness; Resource competition; Various environments (extraatmospheric space, air, water)
• ISSN: 0168-6496; 1574-6941
• DOI: 10.1016/S0168-6496(03)00195-8

A dual isotope labelling technique was used to follow the distribution of carbon and phosphorus in plankton microcosms containing autotrophs ( Tetraselmis sp.), heterotrophic bacteria and herbivores ( Brachionus plicatilis) at eight different total-P concentrations. P:C ratios of algae, bacteria and dissolved matter, as well as the general accumulation of degradable dissolved organic carbon, indicated that both the autotrophs and heterotrophic bacteria were P-limited in all microcosms. According to the theory, such coexistence should only be possible if bacteria have higher predation losses than algae, which was definitely not the case in our experiment. However, data are consistent with the assumption that bacteria are superior in P uptake but have a poor ability to retain acquired P, which would promote coexistence in a patchy P-supply environment resulting from nutrient regeneration by metazoan grazers.