Contribution of humic substances to dissolved organic matter optical properties and iron mobilization
Contribution of humic substances to dissolved organic matter optical properties and iron mobilization
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DOI：
10.1007/s00027-018-0578-z
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发表时间：
2018-04
期刊：
影响因子：
2.4
通讯作者：
Morimaru Kida;N. Fujitake;Vilanee Suchewaboripont;S. Poungparn;M. Tomotsune;M. Kondo;S. Yoshitake;Yasuo Iimura;K. Kinjo;C. Maknual;T. Ohtsuka
中科院分区：
文献类型：
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作者：
Morimaru Kida;N. Fujitake;Vilanee Suchewaboripont;S. Poungparn;M. Tomotsune;M. Kondo;S. Yoshitake;Yasuo Iimura;K. Kinjo;C. Maknual;T. Ohtsuka
腐殖质（HS）是溶解有机物（DOM）的主要成分，在水生系统中起着关键作用。DOM的光学指标，如特定紫外吸光度（SUVA254）、荧光指数（FI）和生物指数（BIX），因其易于使用而受到广泛关注。在本研究中，我们通过不同的旱季和雨季，探讨了泰国东部Trat河流域从源头到河口的HS与指数之间的关系，以检验指数值的变化是否反映了HS对DOM的相对贡献的变异性，或者百分比HS。结果表明，%HS与各指标之间不存在显著的线性关系（FI和BIX，P < 0.05），或存在季节变化关系（SUVA254）。然而，与%HS相比，分析这些指数确实显示出明显的DOM组成随季节的变化，雨季更多的是腐殖质或陆生物质。还探讨了DOM与溶解铁（dFe）浓度之间的关系。将DOM与dFe的关系分为HS与dFe和非HS与dFe，使我们有机会更好地了解哪一部分对dFe的动员贡献更大。结果表明，HS与dFe浓度之间存在较强的线性正相关关系，与河流支流无关。总的来说，本研究强调了HS量化对于研究河流样带DOM动力学或组成变化以及DOM诱导的铁动员的重要性。
Humic substances (HS) are the primary constituents of dissolved organic matter (DOM) and play pivotal roles in aquatic systems. Optical indices of DOM, such as specific UV absorbance (SUVA254), the fluorescence index (FI) and biological index (BIX), have gained wide interest because of their ease of use. In this study, we explored the relationship between HS and the indices in the Trat River Basin (eastern Thailand) from headwaters to the river mouth through the distinct dry and rainy seasons to examine whether changes in index values reflect variability in the relative contribution of HS to DOM, or %HS. The results show that %HS and the indices did not exhibit significant linear relationships (FI and BIX,P> 0.05), or the relationships changed seasonally (SUVA254). However, analyzing the indices versus %HS did show clear DOM composition changes by season with more humic-like or terrestrial material in the rainy season. Relationships between DOM and dissolved iron (dFe) concentrations were also explored. Separating the relationships of DOM versus dFe into HS versus dFe and non-HS versus dFe provides us the opportunity to better understand which fraction contributes more to dFe mobilization. The results indicate stronger positive linear relationships between HS and dFe concentrations independent of river tributary. Overall, this study highlights the importance of quantifying HS for the study of DOM dynamics or compositional changes along a river transect as well as for DOM-induced iron mobilization.