Soluble and Colloidal Iron-Binding Organic Ligands in the Surface Water of Subtropical North Atlantic and North Pacific Oceans

阿拉斯加大学的OCE-0220978A PI计划测量BATS和热区地表水中可溶(0.02微米)和胶体(0.02-0.4微米)中铁和铁结合配体的浓度，以了解铁的化学和物理形态。利用PI开发的一种新的微滤技术，样品将被分成可溶相和胶体相。铁的浓度将通过同位素稀释-高分辨率电感耦合等离子体质谱微分析方法进行测量。用竞争配位平衡/阴极溶出伏安法测定铁络合天然配位体水溶相和胶体相的热力学稳定常数和动力学速率常数。PI还计划评估这两个地点这些参数的空间和时间变异性。这项研究的结果将为模型提供有用的约束，以确定可溶性和胶体铁的生物有效性，从尘埃输入到表层海洋的铁的去向，以及铁对固氮的限制。

OCE-0220978A PI from the University of Alaska plans to measure concentrations of Fe and Fe-binding ligands in the soluble (0.02 um) and the colloidal phase (0.02-0.4 um) of surface waters from the BATS and HOT regions to understand the chemical and physical speciation of Fe. Samples will be separated into the soluble and colloidal phase using a new microfiltration technique developed by the PI. Iron concentrations will be measured by an isotope dilution-high resolution inductively coupled plasma mass spectrometry microanalytical method. The thermodynamic stability constants and kinetic rate constants of Fe-complexing natural ligands in the soluble and colloidal phases will be determined by the competitive ligand equilibration/cathodic stripping voltammetric method. The PI also plans to assess the spatial and temporal variability of these parameters at these two sites. Results from this study will provide useful constraints for models to determine the biological availability of soluble and colloidal Fe, the fate of Fe from dust inputs to the surface ocean and the Fe limitation on nitrogen fixation.