Occurrence of Bioturbation Structures at Estuarine Environment of the Sunderbans, Eastern India

Bioturbation structures produced by the interaction of living organisms and soft sediments have manifested itself in the wide range of forms like tracks and trails, footprints, burrows, mounds, pellets etc. in different geomorphic domains of mesomacrotidal estuarine environment of Sunderbans. Study of behavioural pattern of these organisms through bioturbation structures helps geologists in deciphering the environmental condition prevalent during the intervening period of deposition of soft sediments and their lithification. They may be of lesser magnitude but the processes of bioturbation have the potentiality to alter depositional sequences and sediment chemistry through the process of exhumation and subsurface mixing of sediments as evidenced in cases of burrows in the intertidal muddy flats of Sunderbans. The present paper deals with the interactions of macrobenthos and other organisms with the estuarine sediments of Sunderbans leading to a wide variety of bioturbation structures and also describes their geometry and significance.