Applied Biostratigraphy

Single-celled animals (“protista”), heterotrophic (which means they require food from an external source, just like we do)& some are heterotrophic/symbiotic combination Most with a mineralised wall of some kind (there are some rare “naked” forms) a secreted wall will be calcareous(calcium carbonate - CaCO3) of various crystal arrangements an agglutinated wall can be comprised of any externally-acquired material (usually sand/silt/mud particles) with a calcareous, non-calcareous or organic cement Single or (mainly) multi-chambered all chambers possess one or more openings (Latin; “foramen”) which connect to other chambers Inhabit virtually every marine & marginal marine aquatic niche on earth Biostratigraphically and palaeoenvironmentally significant and the predominant subject of study for microfossil specialists

Subgroup: Planktonic Forams calcareous (secreted hyaline) wall structure geologic range: Middle Jurassic – Recent (still living – “extant”) inhabit open marine water depths between the surface and several thousand metres (over the course of the normal life-cycle) but live mostly in the top 0 – 50/100m of the water column many species exist with symbiotic algae and therefore mainly inhabit the photic zone in eutrophic waters (waters with little or no nutrients) to allow the algae to photosynthesise and provide nutrition percentage of planktonic forams in individual fossil foraminiferal assemblages tends to increase (up to 90%+) with increasing water depth rare at depths shallower than middle shelf (insufficient water depth to carry out the breeding cycle) evolve rapidly and provide excellent stratigraphic resolution

Subgroup: Benthonic Forams Further subgrouping separates Calcareous (secreted hyaline, aragonitic or porcellanous CaCO3) or Agglutinated (the accretion of externally-derived particles to the cell’s surface) forms of wall structure geologic range: Cambrian – Recent (“extant”) some forms can achieve large sizes under warm, clear waters with the incorporation of symbiotic algae within the shell as an additional nutrition source – these are often grouped under the term “Larger Forams” inhabit virtually all marine sediment substrates either on top of (“epifaunal”) or burrowing within (“infaunal”) including hypo- and hyper-saline environments and can also live on the surfaces of plants (“epiphytic”) naked, unfossilisable forms may occur in freshwater agglutinated forms without any calcareous components in the shell predominate in ultra-deep waters (below the CCCD), more restricted environments and/or in conditions of low dissolved O2 can be used to provide very useful paleoenvironmental information and, combined with planktonic forams, can be used to estimate paleodepths