Physico-chemical characteristics of brackishwater ponds along Nethravati Estuary, Mangalore

Abstract

Monsoon and freshwater discharge regulated different physico-chemical parameters. While temperature, salinity and pH decreased during monsoon months, dissolved oxygen was high. In addition to freshwater discharge, local replenishment by the process of regeneration from the bottom/sediments regulated the available phosphate. While ammonia, nitrate and silicate recorded peak values during monsoon, low values of phosphate prevailed during June-August. Reduction in the organic carbon content during post and premonsoon months may be due to higher rate of decomposition. Increased values during July-September may be attributed to settling of dead and decaying planktonic organisms.