Bacteria were counted (direct counts using acridine orange) in soil samples from 12 sites on Marion Island (subantarctic). Numbers, cell types and cell volumes all varied widely between sites; numbers from 7 to 151×108cm-3and from 5 to 1300 g-1oven-dry soil (o.d.s.), volumes from 63 to 825 μ3cm-3and from 61 to 6570 μm3g-1o.d.s. Five main cell shapes were distinguished, and each divided into up to 4 size-classes. Numbers were related negatively to climatic severity and positively to soil nutrient concentrations, vertebrate manuring, and availability of organic substrates. Volumes were not markedly related to climate; the main division was simply between edaphically rich and poor sites. Manured sites and high-altitude sites both had characteristic cell-types, and there was a strong altitudinal sequence of cell sizes among fjaeldmarks. Among the manured sites, seal wallows and albatross nest differed from gull- or penguin-manured sites underCotula plumosa, especially in the proportions of different cell types and sizes. One sample, from a high-altitude fjaeldmark, was totally unlike all others. It was excluded from all general comparisons but it is suggested that this site deserves further study. The combination of numbers, volumes, cell types and sizes, and fluorescence characteristics are interpreted as indicators of contrasting strategies for growth and reproduction, especially high or low “standing crop”vshigh or low turnover, and these strategies related to site cond
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