Foraminiferal biofacies distribution in the outer channel of Chilika Lagoon, Odisha, India

Abstract

Benthic foraminiferal assemblages are widely used as a proxy to monitor the coastal environment’s health. The current work involves the seasonal distribution of foraminifera in the outer channel sector of the Chilika Lagoon, Odisha during 2017–2018. The outer channel is marine as the sea mouth is nearby. Altogether 28 species of benthic foraminifera are identified, among which dominant are Ammonia spp. The other calcareous taxa are Elphidium spp, Quinqueloculina sp., Haynesina spp., Pararotalia sp., Hanzawaia sp., Nonionellina sp. and agglutinated forms such as Miliammina sp., Trochammina sp. and Textularina sp. are found in moderate abundance. Based on the pre-monsoon abundance, the cluster analyses show two distinct biofacies zones in the studied area. Total foraminiferal number (TFN) increases during pre-monsoon compared to post-monsoon months. A trend of decreasing abundance was observed in TFN, mainly calcareous taxa towards the inner part of the lagoon, that is, away from the sea mouth.