Playing in the Mud: Benthic Foraminiferal Communities—Dynamic Environmental Impact Indicators

We show the applicability of the use of foraminifera communities dynamics correlated with abiotic parameters to provide data in environmental quality and coastal management plans. In this sense, we pinpoint sites most subjected to pollution and contamination and we identify differentiate effluents even when salinity and temperature values form gradient. Foraminiferal assemblages show increase in abundance of tolerant species to specific abiotic parameters. Density and diversity negatively correlated with heavy metal and PAHs. Increase in percentages of deformed or abnormal organisms and reduced size of the organism when they are exposed to heavy pollution mainly due to Hg, PAHs, and PCBs. It was observed that tolerant opportunistic species (Ammonia tepida and Buliminella elegantissima) benefit directly from organic contamination increasing their relative abundance. The other type of benefit may be indirect, as has occurred for Elphidium spp., which greatly increases its dominance due to the absence of other species that have had their shells dissolved first, resulting primarily from the impact of the oil spills. On the sedimentary and coral reef areas, Amphistegina gibbosa tests were not found at sites where reefs are walked upon. The presence of hard substrates and coarse sediment, rather than water depth, seems to be controlling the distribution of the tests.The results to date reaffirm the use of foraminiferal species in studies of oil spills, contamination by sewage, and industrial pollution even where the dissolution of carbonate is active due to low pH values. We then conclude that pollution or contamination of an environment overlaps the “natural” zonation and gradient of environmental factors, therefore limiting the establishment of species that are strategists and not opportunists.