title: [Spectral absorption properties of the water constituents in the estuary of Zhujiang River].
abstract: Spectral absorption properties of the water constituents is the main factor affecting the light field under the surface of the water and the spectrum above the surface of the water. Thus, the study is useful for understanding of the water spectral property and the remote reversing of water quality parameters. Absorption properties of total suspended particles, non-algal particles, phytoplankton and CDOM were analyzed using the 30 samples collected in July 2013 in the estuary of Zhujiang River. The results indicated that: (1) the non-algal particles absorption dominated the absorption of the total suspended particles; (2) the absorption coefficient of the non-algal particles, which mainly came from the terrigenous deposits, decreased exponentially from short to long wavelength. In addition, the average value and spatial variation of the slope S(d) were higher than those in inland case- II waters; (3) the absorption coefficient of phytoplankton in 440 nm showed a better polynomial relationship with chlorophyll a concentration, while the absorption coefficient of phytoplankton in 675 nm linearly related with the chlorophyll a concentration. Moreover, the influence of accessory pigments on phytoplankton absorption coefficient mainly existed in the range of short wavelength, and Chlorophyll a was the main influencing factor for phytoplankton absorption in long wavelength. The specific absorption coefficient of phytoplankton decreased the power exponentially with the increase of the chlorophyll a concentration; (4) CDOM mainly came from the terrigenous sources and its spectral curve had an absorption shoulder between 250-290 nm. Thus, a piecewise S(g) fitting function could effectively express CDOM absorption properties, i.e., M value and S(g) value in period A (240-260 nm) showed a strong positive correlation. The M value was low, and the humic acid had a high proportion in CDOM; (5) the non-algal particles absorption dominated the total absorption in the estuary of Zhujiang River, and the contribution of the phytoplankton absorption to the total absorption was far lower than that of the non-algal particles. While the contribution of the CDOM was the lowest. The contribution of the CDOM absorption to the total absorption was relatively larger when the content of humic acid was higher.
authors.forename: Shan-shan
authors.initials: SS
authors.lastname: Wang
authors.forename: Yong-bo
authors.initials: YB
authors.lastname: Wang
authors.forename: Qing-hua
authors.initials: QH
authors.lastname: Fu
authors.forename: Bin
authors.initials: B
authors.lastname: Yin
authors.forename: Yun-mei
authors.initials: YM
authors.lastname: Li
mesh_terms: D002681:China; D002734:Chlorophyll / Q000032:analysis; D000077194:Chlorophyll A; D004784:Environmental Monitoring; D063366:Estuaries; D005618:Fresh Water / Q000032:analysis*; D008027:Light; D010839:Phytoplankton; D045483:Rivers; D013057:Spectrum Analysis; D060753:Water Quality
chemical_list: D002734:Chlorophyll; D000077194:Chlorophyll A