The Sundarbans; the largest single chunk of tidal halophytic mangrove forest in the world; lies in the vast delta on the Bay of Bengal formed by the greater confluence of the Ganges; Brahmaputra and Meghna rivers. It covers 10,000 sq.km of which about 6000 sq.km area is within the political boundary of Bangladesh; and the remaining in India. The area experiences a subtropical monsoonal climate with an annual rainfall of 1600-1800 mm and severe cyclonic storms. Enormous amounts of sediments carried by the rivers contribute to its expansion and dynamics. The Hydro-geochemical environment of this area is highly dynamic in nature with numerous drainage channels and significant coastal processes.
for more info: https://www.omicsonline.org/spatial-and-temporal-variations-in-phytoplankton-abundance-and-species-diversity-in-the-sundarbans-mangrove-forest-of-bangladesh-2155-9910.1000126.php?aid=15302