ELEMENTAL COMPOSITION OF THE POLYPHOSPHATE BODIES IN MICROBIAL-CELLS FROM A SMALL LAKE

Polyphosphate bodies (PPBs) were observed with the electron microscope in air dried preparations of bacteria-sized plankton recovered from l ake water. Analysis of the bodies was carried out using the scanning t ransmission mode (STEM) of the transmission electron microscope (TEM) in conjunction with an energy dispersive X-ray spectrometer (EDX). The bodies in most cells were composed of Mg, P, K and Ca. Some bodies al so possessed S, Cl, Na and Fe. In PPBs from most cells the K peak was low and in some cells it was absent. The PPBs in three different morph otypes also possessed Al. The numerous other cell types did not have A l as a part of their PPBs. The Al containing cell types consisted of a small rod shaped organism 0.3 by 0.6 mum a larger roughly spherical o rganism 1 x 1.5 mum and a large boat shaped organism 3 x 7 mum. The pr esence of Al in the PPBs of these organisms, as well as the other elem ents, demonstrates that metals can be selectively taken up by differen t species in nature. The movement of metals in the food web would be a t least in part dependent on the consumption of these specific organis ms by the next trophic level.