Collaborative Research: Manganese Cycling and Coupling Across Redox Boundaries within Stratified Basins of the Baltic Sea

合作研究：波罗的海分层盆地内锰循环和跨氧化还原边界的耦合

• 批准号: 1924236
• 负责人: Colleen Hansel
• 金额: $ 84.49万
• 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: 2019
• 资助国家: 美国
• 起止时间: 2019-12-01 至 2024-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1924236&HistoricalAwards=false
• 关键词: Collaborative; Research; Manganese; Cycling; Coupling

The trace element manganese (Mn) is distributed widely throughout the global ocean where it cycles among three dominant oxidation states. Manganese in the higher oxidation states is highly reactive and thereby influences the cycling of nearly all other elemental cycles, including those of oxygen and nitrogen. The intermediate Mn species has only recently become recognized as an abundant component of the Mn pool, presenting now a previously unrecognized factor that may control the chemistry of the ocean. The Baltic Sea contains high Mn concentrations and preliminary investigations have pointed to the presence of an operationally defined "reactive" form of Mn but the composition and consequence of this Mn pool are unknown. This research will explore the cycling of Mn within the Baltic Sea enabled by an established collaboration with the Leibniz Institute for Baltic Sea Research in Warnemunde, Germany. By coupling field measurements and targeted shipboard incubations, this study will shed light on the processes controlling the Mn cycle and its link to the oxygen, iodine, and nitrogen cycles. This project will educate several undergraduate and graduate students and promote scientific exchange between research groups within the United States and Germany. Further, outreach efforts associated with this research will continue an existing collaboration between the PIs and the Boston Green Academy in South Boston to introduce high school students to chemical oceanography, and in particular biogeochemistry.Manganese (Mn) is intricately linked to nearly all elemental cycles, and yet we know little about the processes governing its redox cycling within natural systems. Over the past decade a number of key scientific discoveries have provided greater insight into the diversity of processes and mechanisms involved in Mn redox cycling and introduced Mn(III) ligand complexes as important components of the dissolved Mn pool. The Baltic Sea is one of the most well studied stratified marine systems and reactive Mn has been implicated as a key factor in the formation and maintenance of suboxic zones. Thus, the goal of this research is to explore the cycling and elemental coupling of Mn within stratified basins of the Baltic Sea. The PIs predict that reactive Mn, as Mn(III) ligand complexes and Mn oxide particles, is a primary control on the redox landscape of stratified marine waters, particularly at redox boundaries and within the suboxic zone. The PIs propose fieldwork in a local permanently stratified brackish pond to refine experimental procedures followed by two cruises to suboxic basins in the Baltic Sea enabled by an established collaboration with the Leibniz Institute for Baltic Sea Research in Warnemunde. Field measurements will be obtained using a combination of in situ sensors and ship/lab-based instrumentation at several Baltic Sea sites to define the distribution of Mn species and the rates of Mn redox transformations spanning the redoxcline along with a suite of chemical information. Further, a matrix of shipboard incubations will be conducted to constrain the underlying (a)biotic processes responsible for the observed Mn profiles. Specifically, across oxygen and Mn gradients spanning the redoxcline, the PIs will interrogate the link between the Mn cycle and iodine and nitrogen species, which will ultimately help constrain current gaps in the mass balance of these elements in Baltic Sea models.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.

微量元素锰（Mn）在全球海洋中广泛分布，并在三种主要氧化态之间循环。处于较高氧化态的锰具有很强的活性，因此影响几乎所有其他元素的循环，包括氧和氮的循环。中间锰物种直到最近才被认为是锰库的一个丰富组成部分，现在提出了一个以前未被认识到的可能控制海洋化学的因素。波罗的海含有高浓度的锰，初步调查指出存在一种可操作定义的“活性”形式的锰，但这种锰池的组成和后果尚不清楚。这项研究将通过与德国瓦尔内蒙德的莱布尼茨波罗的海研究所建立的合作，探索波罗的海中锰的循环。通过现场测量和有针对性的船上孵育，本研究将阐明控制锰循环的过程及其与氧、碘和氮循环的联系。该项目将培养几名本科生和研究生，并促进美国和德国研究小组之间的科学交流。此外，与这项研究相关的外联工作将继续pi与南波士顿波士顿绿色学院之间的现有合作，向高中学生介绍化学海洋学，特别是生物地球化学。锰（Mn）与几乎所有元素循环都有复杂的联系，但我们对自然系统中控制其氧化还原循环的过程知之甚少。在过去的十年中，一些重要的科学发现为锰氧化还原循环的过程和机制的多样性提供了更深入的了解，并引入了锰（III）配体配合物作为溶解锰池的重要组成部分。波罗的海是研究最充分的分层海洋系统之一，活性锰被认为是形成和维持缺氧带的关键因素。因此，本研究的目的是探讨锰在波罗的海分层盆地内的循环和元素耦合。pi预测，活性Mn，作为Mn（III）配体配合物和Mn氧化物颗粒，是层状海水氧化还原景观的主要控制因素，特别是在氧化还原边界和亚氧区。PIs建议在当地永久分层咸淡水池塘进行实地考察，以完善实验程序，然后与位于Warnemunde的Leibniz波罗的海研究所建立合作关系，前往波罗的海的亚氧盆地进行两次巡航。现场测量将在波罗的海的几个地点使用原位传感器和船舶/实验室仪器的组合来确定Mn物种的分布和Mn氧化还原转化的速率，以及一套化学信息。此外，将进行船上孵育矩阵，以约束导致观察到的Mn剖面的潜在(a)生物过程。具体来说，在横跨氧化多西斜的氧和锰梯度上，pi将询问锰循环与碘和氮物种之间的联系，这将最终有助于限制波罗的海模型中这些元素质量平衡的当前差距。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Particle- and Light-Mediated Processes Control Seasonal Manganese Oxide Cycling in a Meromictic Pond

• DOI: 10.1021/acsearthspacechem.2c00368
• 发表时间: 2023-05
• 期刊: ACS Earth and Space Chemistry
• 影响因子: 3.4
• 作者: H. Gadol;C. Ostrander;Luciana Villarroel;L. Taenzer;S. Wankel;Véronique E. Carignan;C. Hansel