Interstitial water and hydrochemistry of a mangrove forest and adjoining water system, south west coast of India

Eh, pH, salinity, total alkalinity, dissolved O-2, NO2-, PO4-3, SiO2 and NH4+ of waters from a mangrove forest, an estuary and a creek connecting the mangrove forest and the estuary have been measured. Further, the chemistry of interstitial waters of surficial and core sediments from the mangrove forest have been analyzed for the above parameters, except dissolved oxygen. To understand the flux of nutrients from the mangrove forest to the adjoining estuary, creek waters were monitored during tidal phases. PO4-3, SiO2 and NH4+ were found to be at elevated levels in mangrove waters whereas NO2- shows no variation compared to the estuary. Dissolved O-2 is low in mangrove waters. PO4-3, NH4+ and SiO2 are several times higher in interstitial waters than in overlying waters. Several fold enrichment of PO4-3, NH4+ and, to some extent, SiO2 were measured in creek waters during ebbing relative to flooding, indicating that mangroves act as a perennial source for the above nutrients.