Molecular characterization of dissolved organic matter in pore water of continental shelf sediments
Molecular characterization of dissolved organic matter in pore water of continental shelf sediments
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DOI：
10.1016/j.gca.2009.03.008
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发表时间：
2009-06-01
影响因子：
5
通讯作者：
Hinrichs, Kai-Uwe
中科院分区：
文献类型：
--
作者：
Schmidt, Frauke;Elvert, Marcus;Hinrichs, Kai-Uwe
沉积物孔隙水中的溶解有机质（DOM）是一种复杂的分子混合物，反映了多种来源和地球化学过程。为了限制这些来源和过程，从西北伊比利亚大陆架表层沉积物中的孔隙水DOM的分子变化进行了分析，超高分辨率傅里叶变换离子回旋共振质谱（FT-ICR-MS），并比较河流和海洋水柱DOM。重均分子元素氧碳比（（O/C）（wa））和氢碳比（（H/C）（wa））提供了DOM来源的一般信息。与海洋孔隙水DOM（平均（O/C）（wa）0.50，平均（H/C）（wa）1.26）相比，本地河流DOM的含氧量较高（（O/C）（wa）0.52），含氢量较低（（H/C）（wa）1.15）。特定化合物组的相对丰度，如高含氧芳香族化合物或含氮化合物与低H/C比，对应于高浓度的木质素酚（160微克/克沉积物干重）和高TOC/TN比（13.3）的沉积有机物质，因此被分配到陆地来源。较低的不饱和度和较高的相对丰度的含氮化合物在孔隙水DOM反映了沉积物内的微生物活动。一个采样点上的货架上的沉积物积累高，富含腐殖酸的河流样品显示了广泛的含硫化合物的DOM，伴随着较高丰度的硫酸盐还原菌的脂质生物标志物，可能表明早期成岩硫化的有机质。(C)2009爱思唯尔有限公司保留所有权利。
Dissolved organic matter (DOM) in sediment pore water is a complex molecular mixture reflecting various Sources and biogeochemical processes. In order to constrain those sources and processes, molecular variations of pore water DOM in surface sediments from the NW Iberian shelf were analyzed by ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and compared to river and marine water column DOM. Weighted average molecular element ratios of oxygen to carbon ((O/C)(wa)) and hydrogen to carbon ((H/C)(wa)) provided general information about DOM sources. DOM in local rivers was more oxygenated ((O/C)(wa) 0.52) and contained less hydrogen ((H/C)(wa) 1.15) than marine pore water DOM (mean (O/C)(wa) 0.50, mean (H/C)(wa) 1.26). The relative abundance of specific compound groups, such as highly oxygenated aromatic compounds or nitrogen-bearing compounds with low H/C ratios, correspond to a high concentration of lignin phenols (160 mu g/g sediment dry weight) and a high TOC/TN ratio (13.3) in the sedimentary organic matter and were therefore assigned to terrestrial sources. The lower degree of unsaturation and a higher relative abundance of nitrogen-bearing compounds in the pore water DOM reflected microbial activity within the sediment. One sampling site on the shelf with a high sediment accumulation, and a humic-rich river sample showed a wide range of sulfur compounds in the DOM, accompanied by a higher abundance of lipid biomarkers for sulfate-reducing bacteria, probably indicating early diagenetic sulfurization of organic matter. (C) 2009 Elsevier Ltd. All rights reserved.