Optical properties of sediment pore waters of the Adriatic sea

Abstract

Optical properties (Absorption and Fluorescence) and dissolved organic carbon (DOC) of sediment pore waters of cores collected in the Adriatic Sea (Italy) are reported. Correlations among absorption, fluorescence and DOC indicate linear trends only wavelength dependent whatever location and season of sampling. A different behaviour was observed in a station located straight out of the Po river mouth which exhibited a rather different sedimentation regime. Two different fluorophoric groups excited at 280 nm and 355 nm with the emission maxima centered, respectively, at 340–350 nm and 420–470 nm, were recognized. The values of the molar absorptivity (ελ), the slope of the absorption spectra (5), the quantum yields (Fλ) and the Fn(280)/Fn(355) ratios indicate the occurrence in pore waters of low molecular weight (LMW) chromophores with low degree of aromaticity and higher quantum yields than seawater.