Response of size-dependent chemical composition of dissolved organic and inorganic species to land use types in tropical coastal headstreams

文献类型： 外文期刊

第一作者： Ji, Hengkuan

作者： Ji, Hengkuan;Wu, Yueying;Wu, Zhipeng;Li, Caisheng;Hou, Zhengwei;Fu, Peijiao;Chen, Lian;Qiu, Yong

作者机构：

关键词： Dissolved organic matter; Dissolved inorganic matter; Size distribution; Headwater streams; Land use types; Multiple spectroscopic techniques

期刊名称：ECOLOGICAL INDICATORS （ 影响因子：6.9； 五年影响因子：6.6 ）

ISSN： 1470-160X

年卷期： 2023 年 152 卷

页码：

收录情况： SCI

摘要： Land-use types dramatically affect the source, composition, behavior and fate of headstream chemical species. However, the influence of land-use types on the size-dependent composition of dissolved organic matter (DOM) and dissolved inorganic matter (DIM) is still unclear. Here, we evaluated the size-dependent concentration, composition and relationship of chemical species from 9 coastal headstreams (i.e. forested, agricultural and wetland headstreams) using multiple spectroscopic techniques including absorbance, excitation-emission matrix, near-edge X-ray absorption fine structure spectroscopy (NEXAFS), X-ray diffraction (XRD), scanning electron microscopy combined with energy dispersive spectroscopy (SEM-EDS) and synchrotron-based micro-X-ray fluorescence (mu-XRF). Results showed that 68.57%-85.78% of dissolved organic carbon (DOC) with abundant humic/fulvic-like substances were distributed in the <1 kDa fraction in all samples, with a higher percentage in wetland samples. Agricultural land-use increased the export of aluminosilicate minerals in >1 kDa fractions and terrestrial fulvic/humic-like substances from land to stream. Forested streams showed high DOC in the 1 kDa-0.2 mu m fraction, predominance of autochthonous DOM rich in amides, amines, carboxyl and O-alkyl groups, and abundance whitlockite and ferromanganese oxides. Wetland streams were characterized by abundant halite, sylvite, and microbially-transformed humic-like DOM rich in aromatic and phenolic groups. Morphology and correlation analysis implied DIM was closely combined with fluorescent DOM (FDOM) and colored DOM (CDOM), resulting in more irregular organo-inorganic complexes in forested and agricultural streams, and more halite and sylvite crystal blocks encapsulating by smooth and close organic-inorganic complexes in wetland streams. Redundancy analysis (RDA) analysis suggested that land-use types (17.20%) and molecular weight (14.29%) were the prominent factors impacting the composition and relationship of DOM and DIM. Land-use types altered the sources and transport patterns of chemical species in headstreams, influencing their sizedependent compositions and associated biogeochemical processes. Such information is imperative for monitoring and developing land-use policies in coastal regions undergoing intense anthropogenic alterations.

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