This video illustrates the large diversity of protozoan shapes, sizes and modes of movement associated with soil around plant roots. The ecology of rhizosphere protozoa is complex and merits further study. Note the excretion by Mayorella sp. amoeba of groups of particles that do not readily disperse. It is suggested that these particles are enclosed in membranes from bacterial cell wall material of digested prey in a similar manner to that described by S.G.Berk et.al (2008) App. & Enviro. Microbiol. 74, 2187-2199 for the excretion of live Legionella pneumophila by Tetrahymena spp. The possibility exists that different protozoan species may excrete different viable bacteria and that decomposition of these bacteria and other organic matter may be restricted when enclosed in such membranes. Note also the presence of predatory Suctorian ciliates on plant roots and the ciliate Cyrtolophosis sp. in mucilaginous pockets on white clover roots eating large numbers of bacteria.
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