Are strong ligands and dissolved iron tightly coupled in hydrothermal systems?

强配体和溶解的铁在热液系统中紧密耦合吗？

• 批准号: 2122928
• 负责人: Randelle Bundy
• 金额: $ 31.73万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2122928&HistoricalAwards=false
• 关键词: strong; ligands; dissolved; iron; tightly

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).Iron is one of the most abundant elements in the Earth’s crust, but it is extremely diluted in the ocean. Iron-poor surface waters limit the growth of microscopic marine life, called phytoplankton, and their ability to remove carbon from the atmosphere and surface ocean. However, over the last few decades, our understanding of how iron enters the ocean has evolved. Recent data has shown that deep-sea hot springs, also known as hydrothermal vents, impact global iron budgets and are important for surface iron supply. Hydrothermal vents are found globally along volcanic spreading centers where new seafloor is created through tectonic activity. The new porous seafloor allows seawater to circulate through the hot, chemically reactive rocks to create hydrothermal fluids. These fluids are less dense (hotter, 300-400°C) than deep ocean waters (2°C), so the water exiting the vents rises while mixing with ambient seawater, eventually forming hydrothermal plumes. These nutrient-rich plumes can extend for 10-1000s of kilometers into the ocean interior. To account for the long-range transport of hydrothermal iron into the ocean interior, models have shown that stabilizing agents (i.e. organic ligands) are needed to prevent iron from precipitating and settling to the seafloor. However, we still do not know the sources and identities of these organic ligands, as well as how common they are in various hydrothermal systems across the global ocean. Investigating these mechanism(s) for hydrothermal iron stabilization across different vent systems will provide insight into both local and long-range iron utilization by deep-sea marine microorganisms and phytoplankton in the surface ocean. In this project, the sources, concentration, and identities of iron-binding organic ligands in hydrothermal plumes from four different volcanic spreading centers will be examined to understand their impact on iron stabilization and transport into the ocean interior. The major aim of this research is to test whether (1) the concentrations of strong organic ligands tightly control the distal transport of hydrothermally derived dissolved iron in neutrally buoyant plumes across a variety of hydrothermal vent systems and (2) investigate if microbes from hydrothermal systems are responsible for production of these strong organic ligands (i.e. siderophores). This work will use a combination of existing samples and samples of opportunity that will be collected during an upcoming field expedition, each from distinct spreading centers. These findings would significantly enhance our understanding of hydrothermal iron transport and aid in future modeling efforts on the fate of hydrothermal iron in the global iron cycle. This project will support the training of two early career scientists, an undergraduate intern, and STEM workshop kits for middle school programs about deep-sea environments, which will be developed in collaboration and made freely available through the NOAA Pacific Marine Environmental Education and Outreach webpage.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该奖项是根据2021年《美国救援计划法》的全部或部分资助（公共法第117-2）。Ironion是地壳中最丰富的元素之一，但在海洋中非常稀释。贫铁的地表水限制了微观海洋生物的生长，称为浮游植物，及其从大气和表面海洋中去除碳的能力。但是，在过去的几十年中，我们对铁如何进入海洋的数据的理解表明，深海温泉（也称为水热通风孔），影响全球铁预算，对表面铁的供应很重要。沿着火山扩散中心在全球范围内发现水热通风孔，在该中心通过构造活动创造了新的海底。新的多孔海底使海水可以通过热，化学反应性的岩石循环以产生热液液。这些流体比深海水（2°C）较少（热，300-400°C），因此，出口的水与环境海水混合在一起，最终形成水热羽流。这些富含营养的羽毛可以延伸到海洋内部10-1000公里。为了考虑水热铁向海洋内部的远距离运输，模型表明，需要稳定剂（即有机配体）来防止铁沉淀并设置在海底。但是，我们仍然不知道这些有机配体的来源和身份，以及它们在全球海洋各种热液系统中的普遍性。研究这些机制在不同的排气系统上进行水热铁稳定，将为深海海洋微生物和地表海洋中的深海海洋微生物和植物浮游生物提供洞察力。在这个项目中，将检查来自四个不同火山扩散中心的水热羽中的铁结合有机配体的来源，浓度和身份，以了解它们对铁稳定的影响并运输到海洋内部。这项研究的主要目的是测试（1）强有力的有机配体的浓度是否紧密控制着热水衍生的铁的远端转运中性溶解的铁在各种热液排气系统中中性浮力羽流中以及（2）研究水热系统中的微生物是否负责产生这些强有机的有机有机体（即siderophores）。这项工作将结合现有的样本和机会样本，这些样本将在即将到来的实地考察期间收集，每个样本都来自不同的传播中心。这些发现将显着增强我们对水热铁运输的理解，并有助于对全球铁循环中水热铁的命运的未来建模工作。该项目将支持对中学环境的两名早期职业科学家，一名本科实习生和STEM研讨会套件的培训，这些课程将通过合作开发，并通过NOAA太平洋海洋环境教育和宣传网页免费提供，该奖项反映了NSF的法定任务，并通过评估范围来反映出支持者的知识范围，该奖项是通过评估商品的支持。