Identifying Cross-talk between Nitrogen and Manganese Redox Cycling

识别氮和锰氧化还原循环之间的串扰

• 批准号: 1826940
• 负责人: Scott Wankel
• 金额: $ 56.36万
• 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: 2018
• 资助国家: 美国
• 起止时间: 2018-07-15 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1826940&HistoricalAwards=false
• 关键词: Identifying; Cross; talk; between; Nitrogen

Aquatic environments such as wetlands are natural settings in which many chemical elements undergo transformations that play critical roles in Earth's biogeochemical cycles. This research will focus on developing a more detailed understanding of natural reactions between two important elements that undergo such chemical transformations: nitrogen and manganese. Reactions between these elements in aquatic environments have implications for the mobilization of nutrients and metal contaminants in natural waters, the production of gases that play important roles in Earth's atmosphere-climate system, as well as implications for reactions that occurred during early Earth history before the formation of the modern atmosphere. The research will provide training and mentoring opportunities for a graduate student and postdoctoral scholar, and will contribute to the education of undergraduate summer student fellows at the Woods Hole Oceanographic Institution. The researchers will collaborate with the Boston Green Academy to provide science presentations and teaching materials to science teachers, giving a variety of students from underrepresented groups opportunities to participate in research experiences in the Earth sciences.This research will shed new light on the relatively poorly understood coupling of redox reactions between nitrogen (N) and manganese (Mn) in aquatic ecosystems. Although thermodynamic conditions are generally favorable for coupled reactions between N and Mn, evidence for the occurrence of such reactions has remained enigmatic. This research will revisit previously hypothesized reactions between Mn and N, armed with new tools for both Mn and N speciation and isotopic behavior such as advanced soluble and solid-phase Mn-speciation, multi-isotope analyses and flow-through sediment incubations. These techniques will be used to examine abiotic oxidation dynamics of N species by Mn(III)-ligand complexes and other environmentally relevant forms of Mn in naturally dynamic redox zones. The research team will examine the role of reactive forms of Mn such as Mn(III)-ligand complexes and disordered Mn(III/IV) oxides in abiotic transformation of N, and how these abiotic reactions are controlled by the biological production of reactive intermediate species of both N and Mn. The specific objectives are to quantify reaction kinetics and associated isotope effects during oxidation of reduced N species, determine the influence of natural dissolved organic carbon on these reactions, identify reactions between N and Mn intermediates formed by microbes, and examine coupled Mn and N reactions under natural conditions. By bringing new tools to understand these reactions in naturally dynamic redox zones, these results will expand our burgeoning understanding of these reactions, with important implications for aquatic biogeochemistry, fate and transport of natural and anthropogenic nitrogen, impacts of dual isotope signatures of nitrate, mobilization of contaminants and nutrients, production of N-bearing greenhouse gases, and catalysis of early Earth reactions before the Great Oxidation Event.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.

湿地等水生环境是许多化学元素发生变化的自然环境，在地球的地球化学循环中发挥着关键作用。这项研究将侧重于更详细地了解经历这种化学转化的两种重要元素之间的自然反应：氮和锰。这些元素在水生环境中的反应对自然沃茨中营养物质和金属污染物的流动、在地球大气-气候系统中发挥重要作用的气体的产生以及现代大气形成之前的早期地球历史中发生的反应都有影响。这项研究将为一名研究生和博士后学者提供培训和指导机会，并将有助于伍兹霍尔海洋研究所本科暑期研究生的教育。 研究人员将与波士顿绿色学院合作，为科学教师提供科学演示和教材，为来自代表性不足群体的各种学生提供参与地球科学研究经验的机会。这项研究将为水生生态系统中氮（N）和锰（Mn）之间氧化还原反应的耦合提供新的认识。 虽然热力学条件通常有利于N和Mn之间的偶联反应，但此类反应发生的证据仍然是谜。 这项研究将重新审视以前假设的Mn和N之间的反应，配备了新的工具，锰和N的形态和同位素行为，如先进的可溶性和固相锰的形态，多同位素分析和流动通过沉积物孵化。这些技术将被用来研究非生物氧化动力学的N物种锰（III）-配体络合物和其他环境相关形式的锰在自然动态氧化还原区。 研究小组将研究Mn的反应形式，如Mn（III）-配体络合物和无序Mn（III/IV）氧化物在N的非生物转化中的作用，以及这些非生物反应如何由N和Mn的反应中间体物种的生物生产控制。 具体的目标是量化反应动力学和相关的同位素效应在氧化过程中的还原N物种，确定自然溶解的有机碳对这些反应的影响，确定由微生物形成的N和Mn中间体之间的反应，并检查自然条件下的耦合Mn和N反应。通过带来新的工具来理解这些反应在自然动态氧化还原带，这些结果将扩大我们对这些反应的新兴理解，对水生生物地球化学，自然和人为氮的命运和运输，硝酸盐双同位素特征的影响，污染物和营养物的动员，含氮温室气体的产生，该奖项反映了NSF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

The redox fate of hydrogen peroxide in the marine water column

海水中过氧化氢的氧化还原命运

• DOI: 10.1002/lno.11922
• 发表时间: 2021
• 期刊: Limnology and Oceanography
• 影响因子: 4.5
• 作者: Sutherland, Kevin M.;Grabb, Kalina C.;Karolewski, Jennifer S.;Taenzer, Lina;Hansel, Colleen M.;Wankel, Scott D.
• 通讯作者: Wankel, Scott D.

An isotopic study of abiotic nitrite oxidation by ligand-bound manganese (III)

• DOI: 10.1016/j.gca.2020.11.004
• 发表时间: 2021-01-15
• 期刊: GEOCHIMICA ET COSMOCHIMICA ACTA
• 影响因子: 5
• 作者: Karolewski, Jennifer S.;Sutherland, Kevin M.;Wankel, Scott D.
• 通讯作者: Wankel, Scott D.

The Abiotic Nitrite Oxidation by Ligand-Bound Manganese (III): The Chemical Mechanism

• DOI: 10.1007/s10498-021-09396-0
• 发表时间: 2021-05
• 期刊: Aquatic Geochemistry
• 影响因子: 1.6
• 作者: George W. Luther III;J. Karolewski;Kevin M. Sutherland;C. Hansel;S. Wankel