[Excitation-emission-matrix spectral property of dissolved organic matter in seawater of Jiaozhou Bay, China].

Excitation-emission matrix spectroscopy (EEMs) was applied to measure the fluorescence properties of dissolved organic matter (DOM) in seawater collected from Jiaozhou Bay in June, 2005. The study areas include central Bay area, receptor areas of Dagu River, Licun River and Haibo River. The aim was to investigate the influence of discharges from several typical rivers to the receiving seawater. Dagu River discharges mostly freshwater, while the other two rivers discharges include more wastewaters from factories and sewages treatments. The results indicate that there is a redshift of the position of humic-like fluorescence peaks due to the discharges from sewages and wastewaters from factories. The intensities of protein-like and humic-like peaks were the strongest in the samples from area near Haibo River and Licun River, while the weakest fluorescence intensities of both protein-like and humic-like were observed in the samples collected from central bay area. This suggests that river inputs are the mains sources of DOM in seawater of Jiaozhou Bay, while DOM produced by bioactivity in situ dominates those in central Bay area. The relationships of protein-like and humic-like fluorescence intensities vary depending on the water samples. The DOM in seawater of Jiaozhou Bay may be polluted by protein-like organic matter produced by human activity, as indicated by higher ratios of protein-like and humic-like fluorescence intensities. The results suggest the potential utility of EEMs technique for trace DOM and land-based pollution sources.