摘要：Graphical abstractDisplay OmittedAbstractFourier Transform Infrared Spectroscopy (FTIR) was used to study the variations in organic matters of benthic foraminifera(Ammonia beccarii)from four samples collected from beach environments from brackish environments along Tupilipalem coast (South east coast of India). Common absorption bands were observed as peaks in the range of 3600–3400cm−1, 3000–2850cm−1, 1750–1740cm−1, 1640–1600cm−1, 1450–1350cm−1, 885–870cm−1and 725–675cm−1in all the shells ofAmmonia beccarii. The FTIR spectrum of station-1 represents the presence of alkanes (CH3) and alkyl halide (CF stretching) with absorptions at the range 1385–1255 and 1350–1150cm−1were observed and ether (CO stretching) absorption band was observed at stations 1 and 3 with wavenumber of 1115cm−1and 1117cm−1respectively. Alkynes CH bend was observed at station-1 with the wavenumber of 667.43cm−1. The shifting of peak positions in all the samples is could be due to presence of organic matter in the samples. Satellite remote sensing and field observation data revealed that the river mouth at Tupilipalem coast was closed by a sand bar. Consequentially, this waterbody may affect the species diversity.•Positions of the sampling locations were identified using a hand-held Garmin Global Positioning System (GPS).•Foraminifera from the sediment were obtained using a mixture of Bromoform and Acetone.•The functional groups present in the benthic foraminifera shells were recorded in the spectral range of 4000–400cm−1using an FT-IR Spectrophotometer.
