Benthic foraminifera live in a wide variety of marine habitats, from marshes to abyssal plains. Both epifaunal and infaunal adaptations are present. The distribution of species is controlled by a complex of abiotic and biotic variables of the environment, usually resulting in a depth-zonation of assemblages on continental margins.

The composition of the substrate may have a direct or indirect influence on the constitution of the assemblage. Laboratory studies and field observations demonstrate the effects of temperature and salinity variations, particularly on nearshore species. Many calcareous species have algal or chloroplast symbionts; their distribution is partly controlled by light tolerance.

Benthic foraminifera are omnivorous and feed mainly by the pseudopodia. Large supply of nutrients, as in areas of upwelling or water mixing, may give rise to large blooms of opportunistic species.

Marine marshes of diverse geographic locations support some common species. Deep bathyal or abyssal species are widespread, but dominance patterns are apparently associated with identifiable water masses, although causal relations are unclear.