title: Revealing sources and distribution changes of dissolved organic matter (DOM) in pore water of sediment from the Yangtze estuary.
abstract: Dissolved organic matter (DOM) in sediment pore waters from Yangtze estuary of China based on abundance, UV absorbance, molecular weight distribution and fluorescence were investigated using a combination of various parameters of DOM as well as 3D fluorescence excitation emission matrix spectra (F-EEMS) with the parallel factor and principal component analysis (PARAFAC-PCA). The results indicated that DOM in pore water of Yangtze estuary was very variable which mainly composed of low aromaticity and molecular weight materials. Three humic-like substances (C1, C2, C4) and one protein-like substance (C3) were identified by PARAFAC model. C1, C2 and C4 exhibited same trends and were very similar. The separation of samples on both axes of the PCA showed the difference in DOM properties. C1, C2 and C4 concurrently showed higher positive factor 1 loadings, while C3 showed highly positive factor 2 loadings. The PCA analysis showed a combination contribution of microbial DOM signal and terrestrial DOM signal in the Yangtze estuary. Higher and more variable DOM abundance, aromaticity and molecular weight of surface sediment pore water DOM can be found in the southern nearshore than the other regions primarily due to the influence of frequent and intensive human activities and tributaries inflow in this area. The DOM abundance, aromaticity, molecular weight and fluorescence intensity in core of different depth were relative constant and increased gradually with depth. DOM in core was mainly composed of humic-like material, which was due to higher release of the sedimentary organic material into the porewater during early diagenesis.
authors.affiliation: The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing, P.R. China ; State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, P.R. China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Di
authors.initials: D
authors.lastname: Zhang
authors.forename: Zhenyao
authors.initials: Z
authors.lastname: Shen
authors.forename: Chenghong
authors.initials: C
authors.lastname: Feng
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
mesh_terms: D002681:China; D063366:Estuaries; D005163:Factor Analysis, Statistical; D005843:Geography; D019015:Geologic Sediments; D006801:Humans; D009930:Organic Chemicals / Q000032:analysis*; D016062:Porosity; D025341:Principal Component Analysis; D045483:Rivers; D013050:Spectrometry, Fluorescence; D014867:Water / Q000737:chemistry*
chemical_list: D009930:Organic Chemicals; D014867:Water