Absorption and fluorescence spectroscopy are classical tools widely used for characterizing dissolved organic matter (DOM) in natural and engieering systems. The applications of these techniques can be easily expanded to the particulate and sediment organic matter (POM and SOM), after extracting the organic matter from the suspended particles and sediments into the solution. The analysis could be aided by complementary measurements such as the elemental, isotopic, biomarker, and mass spectrometry analysis. This presentation will give one example for the spectral study of POM and SOM in a typical estuary-aquaculture zone-coastal sea continuum. The POM in the aquaculture zone was influenced by a series of processes including the active material exchange across the continuum, strong tides, sediment resuspension, algal production, and microbial transformation. The quantity and composition of SOM in the aquaculture zone were highly dependent on the grain size and related hydrodynamic sorting. The shellfish and laver culture showed an overall limited influence on SOM. The further applications of IsoSource and principal component analysis (PCA) were more sensitive, which identified the removal of SOM by shellfish in the growing season and the contribution from shellfish residuals after the harvest and the cultured laver at some locations. The results suggest the feasible application of spectral characterization for unveiling the variability and mechanisms of organic matter in different forms (i.e., DOM, POM, and SOM) across the land-ocean aquatic continuum.