Seasonal distribution and correlates of transparent exopolymer particles (TEP) in the waters surrounding mangroves in the Sundarbans

•TEP concentration related to phytoplankton abundance dominated by diatom.•The most common diatom species was Skeletonema cf. costatum (Cleve, 1873).•TEP concentration was highest during pre-monsoon relative to monsoon and post-monsoon.•TEP/Chl-a ratio was found to be low in nutrient enriched mangrove water.

In situ concentration of transparent exopolymer particles (TEP) are usually associated with phytoplankton dominated by diatoms and their release of precursor polysaccharide material in the aquatic system. Here, we present temporal data on TEP variation and related habitat parameters for waters surrounding mangroves in the Sundarbans located at the coastal boundary of the Ganges River delta. Over three study years (2009–2011), TEP concentration was highest during the post-monsoon period and was mainly a function of phytoplankton production. The most common diatom species (by percentage of relative abundance) were Skeletonema cf. costatum (Cleve 1873), Ditylum brightwellii (Gosse 1850), and Chaetoceros sp. During the post-monsoon, when phytoplankton was abundant TEP/Chl-a ratio was relatively low and as nutrients depleted from water, phytoplankton biomass declined subsequently, increasing mean TEP/Chl-a ratio in the pre-monsoon.