Source, Composition, and Stability of Soluble Iron Fluxing from Continental Margin Sediments

陆缘沉积物中可溶性铁熔体的来源、组成和稳定性

• 批准号: 1438648
• 负责人: Martial Taillefert
• 金额: $ 49.76万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1438648&HistoricalAwards=false
• 关键词: Source; Composition; Stability; Soluble; Iron

Iron is a limiting nutrient in the world's oceans and plays a key role in regulating the growth of phytoplankton. The main sources of iron to the open ocean are the atmosphere, through wind-blown terrestrial dust, and the seafloor, through input from continental shelf sediments. While atmospheric inputs have been well-studied, the oceanic input of iron from sediments has only sparsely been measured and, as a result, the relative importance of the sediment-derived iron to the iron pool and, ultimately, primary productivity in the oceans is poorly understood. In this study, researchers will examine the chemical properties of sediment-derived iron in the oceans to assess its contribution to the iron used by phytoplankton. Results from this study will further our understanding of iron inputs to the ocean and their importance to ocean primary productivity. The project will contribute to the training of graduate students, as well as provide educational opportunities such as a day at sea for undergraduate students in engineering and physical science.The atmosphere and continental margin sediments are the main source of the limiting nutrient iron (Fe) to the open ocean. Yet, the chemical form of iron from sediments has not been well examined and only quantified as reduced iron or the dissolved iron passing through 0.45 µm filters. The kinetics of iron oxygenation suggests it should precipitate rapidly in the overlying waters, challenging the view that sediments are important sources of iron for primary production. To establish whether the flux of iron from sediments has important implications for primary productivity, possibly rivaling atmospheric inputs, it is necessary to demonstrate that ferric iron originating in sediments is under the form of stable iron species with potential for a high residence time in the water column. The overall objective of this project is to test the hypotheses that iron fluxing across the sediment-water interface in continental margin sediments is dissolved under the form of organic-Fe(III) complexes and that the magnitude of the iron flux is influenced by the redox conditions in the overlying waters, the composition of the complexes, and the biogeochemical processes in the underlying sediments. To test these hypotheses, the flux and speciation of dissolved Fe(III) will be quantified in the sediments of the Carolina depocenter and the Gulf of Mexico, and the biogeochemical processes regulating the production and the flux of iron as a function of the redox regime of the environment will be determined using in situ measurements and state-of-the-art voltammetric and chromatographic techniques.

铁是世界海洋中的一种限制性营养物质，在调节浮游植物的生长方面发挥着关键作用。开阔海洋中铁的主要来源是大气，通过风吹的陆地尘埃，以及海底，通过大陆架沉积物的输入。虽然大气输入已得到充分研究，但对沉积物中的海洋铁输入的测量很少，因此，对沉积物中的铁对铁库以及最终对海洋初级生产力的相对重要性了解甚少。在这项研究中，研究人员将检查海洋中沉积物来源的铁的化学性质，以评估其对浮游植物使用的铁的贡献。这项研究的结果将进一步加深我们对海洋铁输入及其对海洋初级生产力的重要性的理解。该项目将有助于培养研究生，并提供教育机会，例如为工程和物理科学专业的本科生提供海上一天。大气层和大陆边沉积物是开阔海洋中有限营养铁（Fe）的主要来源。然而，沉积物中铁的化学形式尚未得到很好的研究，仅以还原铁或通过0.45 µm过滤器的溶解铁进行定量。铁氧化的动力学表明，它应该迅速沉淀在上覆的沃茨，挑战的观点，沉积物是铁的重要来源，初级生产。为了确定沉积物中的铁通量是否对初级生产力具有重要影响，可能与大气输入相媲美，有必要证明沉积物中的三价铁是稳定的铁物种，具有在水柱中停留时间长的潜力。该项目的总体目标是检验以下假设：在大陆边缘沉积物中，通过沉积物-水界面的铁通量以有机铁（III）络合物的形式溶解，铁通量的大小受上覆沃茨的氧化还原条件、络合物的组成以及下伏沉积物中的地球化学过程的影响。为了验证这些假设，溶解的Fe（III）的通量和形态将被量化的沉积物中的卡罗莱纳沉积中心和墨西哥湾，和调节生产和铁通量作为环境的氧化还原制度的函数的地球化学过程将确定使用原位测量和国家的最先进的伏安和色谱技术。

项目成果

Early Diagenesis in the Hypoxic and Acidified Zone of the Northern Gulf of Mexico: Is Organic Matter Recycling in Sediments Disconnected From the Water Column?

• DOI: 10.3389/fmars.2021.604330
• 发表时间: 2021-03
• 作者: C. Rabouille;B. Lansard;Shannon M. Owings;N. Rabalais;B. Bombled;E. Metzger;Julien Richirt;Eryn M. Eitel;Anthony Boever;J. Beckler;M. Taillefert

Variations in sediment production of dissolved iron across a continental margin not dominated by major upwelling or riverine inputs

• DOI: 10.1016/j.marchem.2020.103750
• 发表时间: 2020-03-20
• 期刊: MARINE CHEMISTRY
• 影响因子: 3
• 作者: Eitel, Eryn M.;Owings, Shannon M.;Taillefert, Martial
• 通讯作者: Taillefert, Martial

Differential manganese and iron recycling and transport in continental margin sediments of the Northern Gulf of Mexico

• DOI: 10.1016/j.marchem.2020.103908
• 发表时间: 2021-01-07
• 期刊: MARINE CHEMISTRY
• 影响因子: 3
• 作者: Owings, Shannon M.;Brethous, Laurie;Taillefert, Martial
• 通讯作者: Taillefert, Martial