Rathgeb Anna, Causon Tim, Krachler Regina, Hann Stephan
Division of Analytical Chemistry, Department of Chemistry, University of Natural Resources and Life Sciences (BOKU Vienna), Vienna, Austria.
Institute of Inorganic Chemistry, University of Vienna, Vienna, Austria.
Electrophoresis. 2016 Apr;37(7-8):1063-71. doi: 10.1002/elps.201500538. Epub 2016 Mar 1.
Iron is an essential micronutrient for all marine organisms, but it is also a growth limiting factor as the iron concentrations in the open ocean are below 1 nmol/L in sea water iron is almost entirely bound to organic ligands of the dissolved organic matter fraction, which are mostly of unknown structure. The input from rivers was traditionally considered as less important due to estuarine sedimentation processes of the mainly colloidal iron particles. However, recent studies have shown that this removal is not complete and riverine input may represent an important iron source in the open ocean. In this context, iron transport by land-derived natural organic matter (NOM), and dissolved organic matter (DOM) have been identified as carrier mechanisms for riverine iron. The aim of this work is to characterize complexes containing iron and other metals in waters simulating estuarine conditions in order to help understand which role iron-DOM compounds play in the open ocean. A method based on size-exclusion chromatography (SEC) with sequential UV/VIS and ICP-MS detection was developed for investigation of DOM size distribution and for assessment of the size-dependent metal distribution in NOM-rich surface water. Furthermore, sample matrix experiments were also performed revealing a dependence of DOM size distribution upon seawater concentration and different compounds present in seawater. Finally, efforts toward determination of DOM size with standardization with typical SEC standards indicate that only relative comparisons are possible with this approach, and that the sample matrix composition strongly influences obtained results.
铁是所有海洋生物必需的微量营养素，但它也是一种生长限制因素，因为开阔海洋中的铁浓度低于1纳摩尔/升，海水中的铁几乎完全与溶解有机物部分的有机配体结合，而这些有机配体的结构大多未知。由于主要是胶体铁颗粒的河口沉积过程，传统上认为河流输入不太重要。然而，最近的研究表明，这种去除并不完全，河流输入可能是开阔海洋中的一个重要铁源。在这种情况下，陆地来源的天然有机物（NOM）和溶解有机物（DOM）的铁运输已被确定为河流铁的载体机制。这项工作的目的是表征模拟河口条件的水体中含铁和其他金属的络合物，以帮助了解铁-DOM化合物在开阔海洋中所起的作用。开发了一种基于尺寸排阻色谱（SEC）并采用顺序紫外/可见和电感耦合等离子体质谱检测的方法，用于研究DOM的尺寸分布以及评估富含NOM的地表水的尺寸依赖性金属分布。此外，还进行了样品基质实验，揭示了DOM尺寸分布对海水浓度和海水中存在的不同化合物的依赖性。最后，用典型的SEC标准进行标准化来测定DOM尺寸的努力表明，用这种方法只能进行相对比较，而且样品基质组成对所得结果有很大影响。
