The Xiamen Symposium on Marine Environmental Sciences (XMAS 2025)

The northeast coastal Bay of Bengal in South Asia is interspersed with several coastal biotopes influenced by the Ganga-Brahmaputra-Meghna delta, among others, and contributes to the sustainable blue economy locally and regionally. Over the last decade, anthropogenic climate change, including relative rise in sea level, coastal erosions, depressions, reduced freshwater flow and altered riverine course, has become a primary driver toward changing ecosystem conditions in the Sundarbans. The present study investigated the seasonal and spatial extent of benthic foraminiferal community across the Sundarbans to identify degraded mangrove patches. Extensive sampling of the significantly different Sundarbans microhabitats highlighted the overwhelming abundance of calcareous taxa Ammonia spp., Quinqueloculina spp. as well as
lower number of agglutinated taxa Entzia macrescens (found exclusively in mangrove forest). The overwhelming abundance of calcareous taxa indicated that the mixing of freshwater with saline water has decreased in recent years. The falling flushing rate can have biological consequences on mangrove vegetation structure and physiology. The infrequent occurrence of Entzia macrescens indicated the degraded mangrove patch, as these taxa are particularly sensitive to mangrove vegetation. Thus, the benthic foraminifera dataset helped towards mapping of severely impacted sites with deteriorating ecological health status and for undertaking future ecological restoration activities to ensure the resilience of Sundarbans mangrove.

mangrove, benthic foraminifera, ecological health