Spectrofluorometric analysis of organic matter in the Sundarban mangrove, Bangladesh

Abstract

Twenty four water samples were collected and analyzed for DOC and optical properties to characterize the origin

and fate of DOM (dissolved organic matter ) along the land and coast continuum in the Sundarban mangrove of Bangladesh. High levels of dissolved organic carbon (DOC) are associated with a highly complex and aromatic character with SUVA₂₅₄ of 7.13-45.05 L mg-C^-1 m^-1. Excitation-emission matrix (EEM) of DOM was analyzed by the parallel factor analysis (PARAFAC); and three different allochthonousfluorophore groups and one autochthonous fluorophore group were identified. Intensive weathering coupled with anthropogenic activities in the catchment area supplied a large amount ofvarying chemistry of allochthonous DOM into the Sundarban mangrove. Emission wavelength bands at particular excitation wavelength were used to estimate Fluorescence Index (FI, 1.38-1.74), Biological/Autochthonous Index (BIX, 0.58-0.72) and Humification Index (HIX, 2.23-4.68), exemplify that fresh and labile DOM from terrestrial sources regulate the carbon cycling in the Sundarban mangrove.