Organic complexation and colloidal association of iron and copper in the subterranean estuary: Implications for trace metal mobility and bioavailability

海底地下水排放（SGD）是一种地下水的平流输送，近年来已被确定为向海洋输送铁和铜等生命必需微量金属的重要来源。据推测，这种运输是促进稳定的金属通过复杂的form-mation和/或胶体协会与溶解的有机质（DOM）。这一过程可能发生在地下河口（STE）的淡水和含盐孔隙水的反应界面，或进入沿海水柱。分布模式，平流通量，和金属有机化合物的化学特性将进行调查（一）实验和（二）在一个模型STE的Spiekeroog岛，德国和韩国济州岛的海底泉，铁和铜的浓度是1-2个数量级高于邻近的沿海海洋。金属-DOM表征的分析挑战将通过结合成熟的粒度分级和物种形成来解决（过滤，伏安法）与最先进的技术：高效液相色谱/体积排阻色谱高分辨电感耦合等离子体质谱（HPLC/HPSEC-HR-ICP-MS）和超高分辨率傅里叶变换离子回旋共振质谱（FT-ICR-MS）分析金属DOM分离物，以揭示特定化合物类别和分子式。这种新的分析方法将提供强大的新工具，研究金属DOM配合物。

Submarine groundwater discharge (SGD), an advective underground water transport, has recently been identified as a large source of life-essential trace metals such as iron and copper to the ocean. It is hypothesized that this transport is facilitated by stabilization of the metals through complex for-mation and/or colloidal association with dissolved organic matter (DOM). This process may take place in the subterranean estuary (STE) at reactive interfaces of fresh groundwater and saline pore water, or upon entry into the coastal water column. Distribution patterns, advective fluxes, and chemical characteristics of metal-organic compounds will be investigated (i) descriptively and (ii) experimentally in a model STE on Spiekeroog Island, Germany and a submarine spring on Jeju Island, South Korea, where iron and copper concentrations are 1-2 orders of magnitude higher than in the adjacent coastal oceans. The analytical challenge of metal-DOM characterization will be addressed by combining well-established size fractionation and speciation (filtration, voltammetry) with state-of-the-art techniques: High-performance liquid chromatography/size-exclusion chromatography high resolution inductively-coupled-plasma mass-spectrometry (HPLC/HPSEC-HR-ICP-MS) and ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) analysis of metal-DOM isolates, to reveal specific compound classes and molecular formulae. This novel analytical approach will provide powerful new tools with which to study metal-DOM complexes.