A first look at the dinoflagellate cysts abundance in the Bay of Bengal: implications on Late Quaternary productivity and climate change

Abstract

Abundance and composition of dinoflagellate cysts in a sediment core (SK218/1) from the Bay of Bengal were examined for the last 23 kyr. Cyst abundance at this site varied from 20 to 153 cysts/g dry wt, which is far less than that reported from other oceans. The Holocene harboured higher number of cysts (74–153 cysts/g dry wt) than the last glacial period (up to 67 cysts/g dry wt). Although cyst abundance is low at this site, the cyst composition and its abundance between Holocene and last glacial period reflect the affinity to climate change between these two periods, like other regions. Greater abundance of heterotroph and autotroph cysts and higher species diversity were noticed during Holocene than in the last glacial period, which supports earlier observations depicting higher productivity during the Holocene than in the last glacial period in the southwest monsoon-influenced regions of the Indian Ocean.