Suspended matter, major cations and dissolved silicon in the estuarine waters of the Mahanadi River, India

Abstract

Results of extensive measurements of suspended matter, major cations Na, K, Mg, Ca and dissolved Si in the waters of the Mahanadi estuary during seven sampling periods between 1977 and 1981 are reported. The particulate concentrations ranged from 0.6 to 596 mg 1⁻¹ during all sampling periods with the highest concentrations occurring in the monsoon season. The mean annual suspended load from the Mahanadi is estimated to be 1.4·10¹⁷ g, almost all of which is monsoonal contribution. Na, K and to a large extent Mg and Ca behave conservatively in the estuary and their annual dissolved fluxes to the Bay of Bengal are: 2.6·10¹⁵, 7·10¹⁴, 1.3·10¹⁵ and 4.2·10₁₅ g, respectively. Si behaves non-conservatively, there is a net removal of 11% of the total annual dissolved Si supply of 3.3·10¹⁵ g to the Bay of Bengal. A major part of this removal occurs during the winter months and appears to be biological.