Collaborative Research: Hydrothermal vent systems mediate the formation and fate of refractory aromatic carbon in the deep ocean

合作研究：热液喷口系统介导深海难熔芳香碳的形成和归宿

• 批准号: 2147634
• 负责人: Sasha Wagner
• 金额: $ 46.79万
• 依托单位: Rensselaer Polytechnic Institute
• 依托单位国家: 美国
• 项目类别: Standard 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=2147634&HistoricalAwards=false
• 关键词: Collaborative; Research; Hydrothermal; vent; systems

Oceanic dissolved organic carbon (DOC) is one of the largest reservoirs of reduced carbon on Earth. Most of this DOC is housed in the deep ocean, where it cycles extremely slowly. Radiocarbon dating shows that the oldest components of oceanic DOC are condensed aromatic compounds. These compounds are also presumed to be unreactive and persistent. This project will investigate whether mid-ocean ridge hydrothermal vents are a source for this fraction of deep ocean DOC, through a field campaign at the well-studied East Pacific Rise 9°N hydrothermal site. Results of this work will advance the understanding of slowly cycling aromatic carbon pools in the abyssal ocean and its sediments, which controls the sequestration of carbon on short and geologic timescales. The project involves three early career researcher investigators, a postdoctoral investigator, and two graduate students.Recent discoveries of (nano)particulate graphite in venting fluids and marine-like isotopic signature of condensed aromatics in oceanic bottom waters suggests a hydrothermal source for those condensed aromatics and warrants further consideration. The proposed research builds upon this previous work by asking: Do hydrothermal vent systems control the formation and distribution of the refractory aromatic carbon that persists in the deep ocean? To answer this question, samples will be collected from hydrothermal vent fields along the well-studied East Pacific Rise 9°N segment to target three main objectives: 1) quantify and characterize aromatic carbon and inorganic geochemistry along a hydrothermal continuum from a range of focused and diffuse fluid temperatures, 2) determine whether thermally altered marine organic matter is the main source of refractory aromatic carbon emitted by hydrothermal vents, 3) provide a preliminary model of the hydrothermal fluxes, dispersal, and fate of particulate and dissolved refractory aromatic carbon in the deep Eastern Pacific Ocean that can be validated and refined with future work. Using multiple analytical proxies to quantify and characterize graphite and soot-type molecules emitted across a broad geochemical range of venting fluids will allow for the determination of which hydrothermal conditions are favorable for the production of refractory aromatic carbon. By studying organic-inorganic interactions, novel datasets for elucidating linked biogeochemical processes will be produced. Complementary isotopic and molecular measurements will reveal whether hydrothermal aromatic carbon is sourced from the thermal alteration of preexisting marine organic matter, challenging the previously-held assumption of a mantle-derived CO2 source. Assessment of off-axis water and sediment transects will confirm whether condensed aromatic carbon that persists in the deep ocean and its sediments is hydrothermal in origin.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.

海洋溶解有机碳（DOC）是地球上碳减少的最大储量之一。该文档的大部分位于深海中，它的循环非常缓慢。放射性碳日期表明，海洋DOC的最古老的成分是凝结的芳香族化合物。这些化合物也表现为无反应和持久性。该项目将通过研究经过良好研究的东太平洋崛起9°N水热遗址的野外运动来调查中海脊中水热通风孔是否是这一部分深海文档的来源。这项工作的结果将进一步了解深渊海洋及其沉积物中缓慢循环的芳族碳池，从而控制碳在短和地质时间刻度上的固相。该项目涉及三名早期职业研究者研究人员，一名博士后研究者和两名研究生。在通风长笛和海洋底部水中凝集芳香剂的（纳米）颗粒石墨的发现（纳米）颗粒石墨表明，这些凝聚的芳香族水解源是这些凝聚的芳香族和征收进一步考虑的水热源。拟议的研究是在先前的工作基础上提出的：水热通风系统是否控制着坚持在深海中的难治性芳香碳的形成和分布？要回答这个问题，将从沿良好研究的东太平洋上升9°N段从热液排气场收集样本，以针对三个主要目标：1）量化和表征芳族碳和无机地球化学沿水热连续连续的无机地球化，从聚焦和差异范围的范围内，确定有机物是否有机化，2）确定是有机物的主要作用。水热通风孔，3）提供了深东太平洋中特定难治性芳香碳的热液通量，分散和命运的初步模型，可以通过未来的工作来验证和精制。使用多个分析代理来量化和表征在广泛的地球化学排气流体范围内排出的石墨和烟灰型分子，将确定哪些热液条件有利于生产耐火芳族碳。通过研究有机无机相互作用，将产生用于阐明链接的生物地球化学过程的新型数据集。互补的同位素和分子测量结果将揭示水热芳族碳是否来自先前存在的海洋有机物的热改变，挑战以前拥有的地幔衍生CO2源的假设。评估离轴和沉积物样带的评估将证实凝结在深海中的冷凝芳族碳及其沉积物的起源是水热。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审查标准来评估，并通过评估来诚实地支持。