Collaborative Research: Volatile Sources and Sinks across the Mariana Forearc

合作研究：马里亚纳弧前的挥发性源和汇

• 批准号: 2151015
• 负责人: Karen Lloyd
• 金额: $ 27万
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2151015&HistoricalAwards=false
• 关键词: Collaborative; Research; Volatile; Sources; Sinks

Volatile elements such as helium (He), carbon (C), and nitrogen (N) are exchanged between Earth’s surface (atmosphere and oceans) and interior (crust and mantle) at volcanic arcs. When an oceanic tectonic plate sinks, or subducts, underneath a continental plate, forming a volcanic arc, these volatiles delivered by the oceanic plate are released in volcanos and seeps across the entire arc system. The efficiency of this transfer controls the composition of Earth’s mantle, atmospheric evolution, and possibly, the global distribution of microscopic life. Despite the importance of global-scale deep volatile cycles, volatile fluxes have not been extensively studied in submarine volcanic environments, as these regions are notoriously difficult to access. Subseafloor boreholes were recently installed in four active serpentinite mud volcanoes in the Southern Mariana forearc. These boreholes offer a unique opportunity to sample large volumes of deeply sourced volatile-laden fluids. This project will sample the boreholes for He, C, and N isotopes, as well as microbiology, to determine how deep volatile cycling is controlled by complex interactions between geochemical and biological processes in the Mariana forearc. These data will enable calculation of forearc volatile fluxes, quantifying biological and geochemical reactions by comparing fluxes of reactive volatiles (C, N) with inert indicators of mantle contributions (e.g., He) and the relative activity levels of known microbial metabolic pathways across the Mariana forearc. Results will be shared through peer-reviewed publications. In addition, a series of four classroom lectures aimed at a high-school level audience will be developed that leverages data and experiences from this project.Volatile elements are exchanged between Earth’s exterior (atmosphere and oceans) and interior (crust and mantle) at convergent margins. Volatiles are input via subduction and released in volcanos and seeps across the entire arc system. The efficiency of this transfer controls mantle heterogeneities, Earth’s redox conditions, atmospheric evolution, and possibly, the global distribution of microscopic life. Despite the importance of global-scale deep volatile cycles, volatile fluxes have not been extensively studied in submarine volcanic forearcs, as these regions are notoriously difficult to access. Recently emplaced boreholes provide a unique opportunity to sample large volumes of deeply-sourced pristine volatile-laden fluids across a wide expanse of the submarine Mariana forearc. However, volatile outfluxes may be complicated by the fact that shallow forearc temperatures are amenable to life, and thus some of these deeply derived (i.e., from the subducting slab and/or mantle) volatiles (e.g., CO2, CH4, NH4+) may be altered by subsurface microbes. This project will determine forearc volatile fluxes, quantifying biological and geochemical reactions by comparing fluxes of reactive volatiles (C, N) with inert indicators of mantle contributions (e.g., He) and the relative activity levels of known microbial metabolic pathways across a transect of the Mariana forearc. This project will leverage previously emplaced boreholes that have never been sampled for He, C, and N isotopes, or microbiology, to determine how volatile recycling efficiency is controlled by complex interactions between geochemical and biological processes in the Mariana forearc. Cased boreholes were recently installed in four active serpentinite mud volcanoes in the Southern Mariana forearc. Together, these four boreholes form a trench-parallel transect, enabling access to deep fluids from active serpentinite mud volcanoes across the Mariana forearc. This project will gather geochemical and biological data from these boreholes, enabling a systematic assessment of forearc volatile fluxes and the key processes (e.g., calcite precipitation, heterotrophy, autotrophy, respiration) mediating those fluxes. This will determine volatile (He, C and N) fluxes between Earth reservoirs and quantify their sources (slab, mantle wedge, crust) and sinks (geochemical and biological). Boreholes are located at different distances from the trench and the emanating fluids have varying pH and temperatures, so the dominant biological and geochemical processes at each borehole are expected to vary. In addition to training two PhD students and undergraduate students, the PIs have a broad outreach plan that incorporates media outlets and collaborations with science museums, underrepresented high schools, and undergraduate researchers. Specifically, the PIs will develop a series of four classroom lectures and activities aimed at a high-school level audience that leverages data and experiences from this project.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.

在火山弧的地球表面（大气和海洋）和内部（地壳和地幔）之间交换了诸如氦（He），碳（C）和氮（N）之类的挥发性元件。当海洋构造板板下沉或托运板在连续的板下方形成火山弧下，这些由海洋板传递的火山被释放在整个弧系统中，并在整个弧系统中渗出。这种转移的效率控制着地球地幔的组成，大气进化以及可能的显微镜寿命的全球分布。尽管全球尺度的深度挥发性周期很重要，但在海底火山环境中的挥发性磁通量并未广泛研究，因为众所周知，这些地区很难进入。最近在南部玛丽安娜前牙的四个活跃的蛇形泥石火山中安装了子虫钻孔。这些钻孔提供了一个独特的机会，可以品尝大量深层挥发性的通量。该项目将为HE，C和N同位素以及微生物学采样钻孔，以确定玛丽安娜前胞体中的地球化学和生物学过程之间的复杂相互作用来控制深层挥发性循环。这些数据将能够计算前臂挥发性通量，通过比较反应性挥发物（C，N）的通量与地幔贡献（例如HE）的惰性指标（例如HE）和跨Mariana跨Mariana earearc的已知微生物代谢途径的相对活性水平来量化生物学和地球化学反应。结果将通过同行评审的出版物共享。此外，还将开发一系列针对高中级受众的四个教室讲座，以利用该项目的数据和经验。挥发性元素在地球外部（大气和海洋）和融合边缘的内部（大气层和海洋）和内部（地壳和地幔）之间进行交换。挥发物是通过俯冲输入的，并在火山中释放，并在整个弧系统上看到。这种转移的效率控制着地幔异质性，地球的氧化还原条件，大气进化以及可能的全球微观寿命分布。尽管全球尺度的深度波动周期很重要，但在海底火山前牙前的挥发性磁通量并未广泛研究，因为众所周知，这些地区很难进入。最近出现的钻孔提供了一个独特的机会，可以在广泛提取海底Mariana前牙中的大量深层原始的原始挥发性烟道中进行采样。然而，浅表前臂温度可以适应寿命，因此，这些深层衍生（即，从俯冲板和/或地幔）挥发物（例如CO2，CH4，NH4，NH4+）可能会通过地下微底片更改。该项目将通过比较反应性挥发物（C，N）的通量与地幔贡献的惰性指标（例如HE）以及跨Mariana eariana eareArc横断面的已知微生物代谢途径的相对活性水平，从而确定前提挥发性通量，从而量化生物学和地球化学反应。该项目将利用以前从未为HE，C和N同位素或微生物学取样的钻孔来确定Mariana前臂中地球化学和生物学过程之间复杂的相互作用的挥发性回收效率如何控制。最近，在玛丽安娜（Mariana）南部前牙的四个活跃的蛇形泥石火山中安装了壳体钻孔。这四个钻孔在一起形成了一个沟渠平行的样带，从而使从玛丽安娜前臂上的活性蛇纹石泥石火山中进入深水流体。该项目将从这些钻孔中收集地球化学和生物学数据，从而实现对前臂挥发性通量的系统评估，以及关键过程（例如，钙降水，异性营养，自身萎缩，呼吸，呼吸），介导这些磁通量。这将确定地球储层之间的挥发性（HE，C和N）通量，并量化其来源（平板，地幔楔，地壳）和水槽（地球化学和生物学）。钻孔位于与沟渠不同的距离，发射烟的pH值和温度变化，因此每个钻孔的主要生物学和地球化学过程预计会有所不同。除了培训两名博士生和本科生外，PIS还制定了广泛的外展计划，该计划与科学博物馆，代表性不足的中学和本科研究人员结合了媒体和合作。具体来说，PI将开发一系列四个课堂讲座和活动，旨在利用该项目的数据和经验，该奖项反映了NSF的法定任务，并通过使用基金会的知识分子优点和更广泛的影响标准来评估NSF的法定任务。

项目成果

Chemolithoautotroph distributions across the subsurface of a convergent margin

会聚边缘地下的化学自养生物分布

• DOI: 10.1038/s41396-022-01331-7
• 发表时间: 2023
• 期刊: The ISME Journal
• 作者: Rogers, Timothy J.;Buongiorno, Joy;Jessen, Gerdhard L.;Schrenk, Matthew O.;Fordyce, James A.;de Moor, J. Maarten;Ramírez, Carlos J.;Barry, Peter H.;Yücel, Mustafa;Selci, Matteo
• 通讯作者: Selci, Matteo

Magmatic Carbon and Helium in Springs Reveals the Vitality of a Dormant Volcano, Taranaki, New Zealand

泉水中的岩浆碳和氦揭示了新西兰塔拉纳基休眠火山的活力

• DOI: 10.1029/2022gl099273
• 发表时间: 2022
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Werner, C.;Schipper, C. I.;Cronin, S. J.;Barry, P. H.;Stewart, M. K.
• 通讯作者: Stewart, M. K.

The Helium and Carbon Isotope Characteristics of the Andean Convergent Margin

• DOI: 10.3389/feart.2022.897267
• 发表时间: 2022-06-13
• 期刊: FRONTIERS IN EARTH SCIENCE
• 影响因子: 2.9
• 作者: Barry, P. H.;De Moor, J. M.;Giovannelli, D.
• 通讯作者: Giovannelli, D.