Phosphorus cyeling in aquatic microorganisms studied by phased uptake of33P and32P

An isotopic technique using³²P and³³P simultaneously was developed to examine cellular and intracellular phosphorus cycling in microorganisms. The method was tested with cultures of two algae (Ankistrodesmus sp. andDunaliella tertiolecta) and a marine bacterium (Beneckea natriegens). Intact cells and intracellular fractions showed phosphorus cycling, with the fastest exchange rates being observed in the pool extracted by hot water. The technique should also be applicable to cell and tissue cultures or simple microcosms.