Changes in depositional environment of the Savitri (tropical) estuary, central west coast of India

Abstract

Transformation of coastal regions as a result of recent climate change and localised human influences is of concern. Thus, understanding of the changes that have already occurred, the processes responsible for these changes, and their impact on coastal depositional environment is important. Large and well-developed intertidal mudflats of Savitri estuary of central west coast of India are well suited for this purpose. The distribution of sediment components, total organic carbon, total nitrogen, total phosphorous, sedimentary organic carbon isotope ratios (Delta sup(13) C sub(org)), diatoms, pH, and metals (Fe, Mn, Al, Ni, Cr, Co, Zn, Pb) of two mudflat sediment cores, S-18 from lower estuary and S-41 from middle estuary of Savitri estuary, are presented in this paper. The enrichment of Delta sup(13) C sub(org) values from bottom to surface as well as dominance of marine diatom species towards the surface of core S-18 was attributed to the decrease in freshwater inflow to the estuary as a result of decreased rainfall, and runoff, while, increase in organic nutrient load in cores S-18 and S-41, was may be due to input from anthropogenic activities in recent years and changes in depositional environment of Savitri estuary.