Using benthic foraminifera as bio-indicators of anthropogenic marine pollution in southern Sydney, Australia

Benthic foraminiferal communities are excellent bio-indicator tools for both natural and anthropogenic marine pollution in coastal marginal-marine settings. Their abundance and diversity, together with their relationships to environmental parameters such as grain size, organic carbon and heavy metal contents of surface sediments in southern Sydney estuaries, Australia, make them ideal subjects to explore the effects of marine pollution. A total of 21 surface sediment samples were selected from estuaries, bays and rivers that represent mud with high concentrations of heavy metals, mud with low concentrations of heavy metals, sandy silt and fine-grained sand to explore their foraminiferal assemblages. Eighty two benthic foraminifera species belonging to 31 families and 55 genera were recognized. The results revealed that tolerant and opportunistic foraminiferal species that exist in harbours and estuaries contaminated with heavy metals were dominated by Ammonia beccarii, Bolivina spathulata and Cribroelphidium excavatum. Furthermore, foraminifer species diversity and abundance were at their highest in fine sand, sandy silt, and muddy sediments, which have low concentrations of heavy metal pollution. Supplementary Figure S1 and Supplementary Tables S1-S4 provide additional data on which this research is based.