Abstract
Sundarbans, the world's largest contiguous mangrove wetland, a UNESCO World Heritage Site and a RAMSAR site formed on the delta of Ganga-Brahmaputra-Meghna (GBM) and influenced by coastal water entering from the Bay of Bengal contribute immensely to biodiversity and blue economy. To track the changes driven by natural and anthropogenic stressors, sediment based environmental DNA (eDNA) biomonitoring of benthic foraminifera communities, an important biological group sensitive to changes, has been initiated along with estimation of dissolved nutrients from estuarine surface water of Sundarbans. In pre-monsoon of 2022 (June), sediment cores and surface water were collected as well as in situ environmental parameters were measured from two pre-designated sampling points of Sundarbans to elucidate the benthic foraminifera community based on sediment eDNA approach. Based on Oxford Nanopore Technologies (ONT) sequencing in MinION platform, high abundance of Sorites sp., Elphidium excavatum, Textularia gramen, Quinqueloculina sp. and Trochammina hadai were detected. The increasing nutrient concentrations and elucidated benthic foraminiferal signals can contribute towards tracking the state of ecological health of Sundarbans. This study is aimed at generating baseline information on mangrove benthic foraminifera communities using sediment eDNA based high-throughput sequencing.