ABSTRACT
Details of the distributions of associations of species in different environments throughout the world have already been described in Chapters 6–17. The more important abiotic ecological parameters include water temperature, salinity, energy and turbidity, and the nature of the substrate. Although one factor may appear to be most significant, the total range of a species or an association is invariably controlled by a plexus of factors. Biotic parameters include the availability of food and the effects of predation. Neither is limiting but both influence the abundance of individuals. To a certain extent foraminifera have evolved non-competitive feeding strategies which are most clearly seen in shallow-water environments where herbivores, detritivores, omnivores and passive suspension feeders may coexist. Exclusion of macrobenthic predators under experimental conditions or in dysaerobic/anoxic environments leads to higher standing crop values. In response to oligotrophic conditions where nutrients are in very low supply, certain foraminifera have evolved an endosymbiotic relationship with algae which enables them to achieve both moderate densities and large size.
