Benthic foraminifera as potential ecological proxies for environmental monitoring in coastal regions: A study on the Beypore estuary, Southwest coast of India.

Abstract The benthic foraminiferal diversity index was computed from Beypore estuary sediments. The abundance and diversity of Quinqueloculina lata , Textularia agglutinans , Haplophagmoides canariensis , and Quinqueloculina stelligera were dominated by stress-tolerant taxa such as Ammonia tepida , A.parkinsoniana , Nonion grateloupi , and N. scaphum in the estuary. The small-size foraminifera probably perished in a juvenile stage because of the high temperature and low salinity that prevailed in the ecosystem. The dominance of stress tolerant benthic foraminifera and absence of Elphidium species in the estuary suggest the prevalence of hypoxic (low-oxygen) conditions. The consistent low-diversity index of foraminifera indicates that the ecosystem is moderate to highly stressed ecologically in the Beypore estuary. The application of benthic foraminifera as a bioindicator for assessing the environmental stress in the Beypore estuary is key in monitoring these fragile coastal ecosystems. Highlights • First comprehensive attempt to employ benthic foraminifera as a bioindicator for assessing the environmental stress. • Diversity and abundance of foraminifer assemblage were dominated by stress- tolerant taxa. • Foram tests were probably perished in a juvenile state due to environmental stress. • FORAM Index (FI) with < 1.5 value, adequately indicate that the ecosystem is moderate to highly stressed. [ABSTRACT FROM AUTHOR]