The distribution of foraminiferal taxa is influenced by many different factors. Although many authors consider water depth the most significant one, water depth in itself is not important, the controlling factors being the various physical and chemical conditions associated with depth. Some of these factor are:
1. Temperature and temperature fluctuations
Some foraminiferal species have a wide tolerance, other have narrow tolerance limits. Most of the shallow water environments on a world wide basis, are controlled by temperature differences.
2. Salinity and salinity variations
Most foraminiferal species tolerate only small changes in salinity. In marginal marine environments, where salinities can be low, due to the mixing with freshwater, characteristics high tolerance assemblages will be found. Especially miliolids are suspectible to low salinities, if less than 32% no miliolids will be present.
3. Calcium carbonate availability
Salinity, temperature and CO2 content of the seawater influence the solubility of calcium carbonate. In tropical marine and hypersaline waters calcium carbonate is most readily available. Cool hyposaline waters contain very little calcium carbonate and consequently faunas will consists mostrly of arenaceous species
4. Oxygen content
Foraminifera do not live in an oxygenic conditions, otherwise oxygen is no limiting factor
5. Energy
6. Pressure
7. Light
Foraminiferal growth will be affected through algae or non algae food supple. The precise effect of light on the distribution of foraminifera is unknow
8. Rate of sedimentation
Krashininnikov (1960): different faunal facies occur at the same depth. Depending on the rate of sedimentation and bottom charecters. For instance, Elphidium prefers mobile water aand rapid sedimentation, while miliolids prefer quiet water and slow sedimentation
9. Bottom Characters
The presence of a sandy, muddy or rocky substratum will influence the distribution of foraminifera.