Examining marine particulate organic matter at sub-micron scales using scanning transmission X-ray microscopy and carbon X-ray absorption near edge structure spectroscopy
Examining marine particulate organic matter at sub-micron scales using scanning transmission X-ray microscopy and carbon X-ray absorption near edge structure spectroscopy
复制标题
DOI：
10.1016/j.marchem.2004.06.020
复制
发表时间：
2004-12-01
期刊：
影响因子：
3
通讯作者：
Cody, G
中科院分区：
文献类型：
--
作者：
Brandes, JA;Lee, C;Cody, G
海洋沉降颗粒有机物（POM）代表了海洋沉积物中表层初级生产与有机物埋藏之间的联系。因此，该材料的性质一直是试图表征其组成的许多研究的主题。这些研究的结果表明，一个显着的比例POM是不可识别的已知化合物，和未表征的材料的比例增加与年龄/深度/成岩作用。然而，很少有研究探讨这种材料的空间异质性。本研究使用了一种新的工具，扫描透射X射线显微镜（STXM），连同碳X射线吸收近边结构（C-XANES），检查POM收集沉积物陷阱部署在一个位置在阿拉伯海作为JGOFS计划的一部分。结果表明，POM主要由四个不同的相组成：蛋白质，脂肪族丰富的相，羧酸丰富的相，和一个复杂的不饱和和醌的字符相。这最后一个阶段可能是碳水化合物和蛋白质之间的缩合产物，或来自降解的植物色素。许多颗粒由单一化学相组成;然而，在具有混合成分的颗粒中，各个域在仪器的分辨率极限（50 nm）下保留了独特的化学特征。所有主要的化学相，观察到沉积物陷阱颗粒从531至3369米深度，支持的假设，非选择性降解占主导地位的颗粒微生物化，和整体颗粒组成是由近表面的过程。只有一个粒子，超过60个检查，表现出煤烟样的组合物。缺乏一个显着的黑碳/烟尘成分可能是由于在冬季季风期间采样。(C)2004 Elsevier B. V.保留所有权利。
Marine sinking particulate organic matter (POM) represents the link between surface primary production and burial of organic matter in marine sediments. As such, the nature of this material has been the subject of numerous studies attempting to characterize its composition. The results of these studies have shown that a significant proportion of POM is not recognizable as known compounds, and that the proportion of uncharacterized material increases with age/depth/diagenesis. However, few studies have examined the spatial heterogeneity of this material. This study uses a new tool, scanning transmission X-ray microscopy (STXM), together with carbon X-ray absorption near edge structure (C-XANES), to examine POM collected from sediment traps deployed at one location in the Arabian Sea as part of the JGOFS program. The results indicate that POM is composed primarily of four distinct phases: protein, an aliphatic rich phase, a carboxylic-acid-rich phase, and a phase with complex unsaturated and quinone character. This last phase may be a condensation product between carbohydrates and proteins, or from degraded plant pigments. Many particles consisted of a single chemical phase; however, in particles with mixed compositions, individual domains retained distinctive chemical signatures at the instrument's resolution limit (50 nm). All major chemical phases were observed in sediment trap particles from 531 to 3369 m depth, supporting the hypothesis that non-selective degradation dominates particle remineralization, and that overall particle compositions are determined by near surface processes. Only one particle, out of more than 60 examined, exhibited soot-like composition. The lack of a significant black carbon/soot component may be attributable to sampling during the winter monsoon period. (C) 2004 Elsevier B.V. All rights reserved.