Gallionella from metalimnion in an eutrophic lake: morphology and X-ray energy-dispersive microanalysis of apical cells and stalks

Abstract

The genus Gallionella constitutes a major microbial population in the metalimnion of an eutrophic lake. The normal morphology of this pelagic community is spherical to rod-shaped apical cells on fibrillar, nontwisted, dichotomously branching stalks. X-ray energy-dispersive microanalysis of stalks and apical cells established that the stalks do not contain phosphorus and are thus unlikely to represent living cellular material. Iron in the stalks forms a gradient, the lowest concentration being found proximal to the apical cells and highest concentration in the distal end of the stalk.