Fluorescent characteristics of dissolved organic matters in soil at Water-level-fluctuating zone(WLFZ) in Kaixian of Three Gorges Reservoir and their spacial distributions

The DOM compositions at WLFZ in Kaixian of Three Gorges Reservoir Area, the location features and spatial distribution of fluorescence peak were studied by using Three-dimensional fluorescence spectroscopy. The results show that most DOM in soil at the WLFZ contain humic-like fluorescence peaks A and C, tryptophan-like fluorescence peaks B and D, and only some soils contain tyrosine-like fluorescence peaks E and F. The positions of humic-like fluorescence peaks in the visible region and ultraviolet region of DOM change greatly; the positions of tyrosine-like fluorescence peaks in longer wavelengths change slightly. Soil humus is the main source of DOM i, and it is mainly composed by humic substances. The trends of spatial changes of humic-like fluorescence intensities in visible region and in ultraviolet region are roughly the same; the trend of spatial changes of tryptophan-like fluorescence intensities is consistent with that of humic-like in the shorter wavelengths.