Collaborative Research: Characterization of Iron Binding Organic Ligands in Seawater

合作研究：海水中铁结合有机配体的表征

• 批准号: 0751733
• 负责人: Daniel Repeta
• 金额: $ 46.8万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-03-01 至 2012-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0751733&HistoricalAwards=false
• 关键词: Collaborative; Research; Characterization; Iron; Binding

OCE-0751733OCE-0751822Iron is an essential element in many key biochemical processes, including respiration, nitrogen fixation, nitrate reduction, and chlorophyll biosynthesis. Iron speciation measurements show that 99% of dissolved iron is complexed by organic ligands that form very strong ferri-organic complexes that help stabilize Fe(III) in seawater, increasing its concentration to levels that can sustain microbial growth. However, the composition of these ligands that play an important role in the marine iron cycle remains largely unknown. Scientists from Woods Hole Oceanographic Institution and the University of Southern California propose to characterize the naturally occurring iron-binding ligands. Specifically, the investigators plan to collect strong iron-binding ligands from very large volume (104 L) samples and perform detailed spectral analysis (mass spectrometry and nuclear magnetic resonance spectroscopy) to determine ligand distributions, functional group characteristics, and ultimately the structures of major ligands. Preliminary results from the North Pacific Ocean show our collection protocol recovers 60% of Fe-ligand complexes and 25-30% of total ligands. Measured conditional stability constants of the ligand extract (Kcond L/Fe' 1012) and competitive isotopic (55Fe and Ga (III)) labeling in the presence of strong chelators (EDTA, DTPA, DFB) allows us to target only strong ligands for spectral analysis. Characterization of naturally occurring iron binding ligands would provide a better understanding of iron speciation in seawater, and complement on-going studies of Fe-ligand bioavailability in pure cultures and mixed assemblages of marine plankton.As regards broader impacts, a Fulbright postdoctoral scholar would participate in the research. One graduate student from the University of Southern California would be supported and trained as part of this project. One high school student would also be supported and trained as part of this project at the Woods Hole Oceanographic Institution. In addition, it is anticipated that undergraduate students supported via the Woods Hole Oceanographic Institution summer student fellowship program would participate in the study.

OCE-0751733OCE-0751822铁是许多关键生化过程的必需元素，包括呼吸作用、固氮、硝酸盐还原和叶绿素生物合成。铁形态测量表明，99%的溶解铁与有机配体络合，形成非常强大的铁-有机络合物，有助于稳定海水中的铁(III)，使其浓度增加到能够维持微生物生长的水平。然而，这些在海洋铁循环中发挥重要作用的配体的组成在很大程度上仍不清楚。来自伍兹霍尔海洋研究所和南加州大学的科学家们提议对自然产生的铁结合配体进行表征。具体地说，研究人员计划从非常大的数量(104个L)样本中收集强铁结合配体，并进行详细的光谱分析(质谱分析和核磁共振光谱分析)，以确定配体的分布、官能团特征，并最终确定主要配体的结构。来自北太平洋的初步结果表明，我们的收集方案回收了60%的铁配体络合物和25%-30%的总配体。在强络合剂(EDTA，DTPA，DFB)存在下，测定了配体萃取物(Kcond L/Fe‘1012)和竞争同位素(55Fe和Ga(III))的条件稳定常数，使我们能够只针对强配体进行光谱分析。表征天然存在的铁结合配体将有助于更好地了解海水中铁的形态，并补充正在进行的关于铁配体在海洋浮游生物纯培养和混合组合中的生物有效性的研究。至于更广泛的影响，富布赖特博士后学者将参与这项研究。南加州大学的一名研究生将作为该项目的一部分得到支持和培训。作为这一项目的一部分，伍兹霍尔海洋研究所还将支持和培训一名高中生。此外，预计通过伍兹霍尔海洋研究所暑期学生奖学金计划支持的本科生将参与这项研究。