Original paper

Picoplanktonic Cyanophytes from three small lakes with special reference to polyphosphate bodies

Jensen, Thomas E.; Corpe, William

Algological Studies/Archiv für Hydrobiologie, Supplement Volumes No. 75 (1995), p. 149 - 156

25 references

published: Oct 27, 1995

DOI: 10.1127/algol_stud/75/1995/149

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ArtNo. ESP142010500015, Price: 29.00 €

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Abstract

Two cyanobacterial morphotypes were observed in water from 3 small oligotrophic lakes in Black Rock Forest near Cornwall, N. Y. (U.S.A.). They were isolated as a part of the picoplanktonic biomass (2.0 µm and smaller) using screens and filters followed by high speed centrifugation. Fixed cells in thin sections were examined in the electron microscope (TEM). The two blue-greens were a coccoid shaped cell (1.1 µm in diameter) and a rod shaped cell (0.5 µm in diameter and 1.2 µm in length). They were determined to be cyanophytes by their internal membranes and polyhedral bodies. Polyphosphate bodies were observed in about 50 % of the picoplankton cells, in thin sections, including the blue-greens. Many of the polyhedral bodies contained "mini-polyphosphate bodies". Cells of the picoplankton biomass were also air dried onto formvar coated grids. Elemental analysis of the cells and polyphosphate bodies was carried out using the scanning transmission mode of the TEM in conjunction with a PGT energy dispersive x-ray spectrometer. The polyphosphate bodies of the spherical cells possessed C, O, Mg, Al, P, S, Ca and generally K. Some of the bodies also contained Na and Fe. The cytoplasm showed small peaks for C, O, P, S and Ca. The rod shaped blue-greens had the same morphology as several other bacterial morphotypes and could not be identified in air dried material. The variation in elemental make-up of polyphosphate bodies in cells in the same environment indicates that cells possess specific and different systems for uptake of and sequestering of metals. These results indicate that polyphosphate bodies may be a major site for concentrating elements by cells in the natural environment.

Keywords

Cyanobacteria (Cyanophytes) • picoplankton • polyphosphate bodies • elemental analysis