The rise of environmental micropalaeontology and palaeoecology
By the late nineteenth century, reports of foraminiferal distributions by pioneers such as Alcide d’Orbigny, Jacob Bailey and Henry Brady led to the realization that benthic foraminiferal populations have a biogeography, and are strongly influenced by water temperatures. Later studies, especially those by Richard Norton and Manley Natland in the 1930s, confirmed the temperature effect. The salinity effect became well known by late 1950s. In the 1950s and 1960s, environmental influences, including that of dissolved oxygen, became clearer with the extensive work of Fred Phleger and associates in the Gulf of Mexico, and in the western North Atlantic and eastern North Pacific Oceans. During this time, Orville Bandy and his students demonstrated severe changes in foraminiferal assemblages at California sewage outfalls. Furthermore, in Argentina, Esteban Boltovskoy confronted questions of species abundances and morphology, as related to natural and anthropogenic environmental constraints. A decade later, George Seiglie recognized anomalous populations and morphological abnormalities in polluted Puerto Rican bays. Thus, today’s approach to environmental micropalaeontology, using benthic foraminifera as a tool, was well established by the early 1970s. The emphasis, however, has shifted since then from environmental effects on assemblage characteristics (diversity, dominance, morphological aberrations) to the use of assemblages or species as tracers of environmental changes in historical time.