Nutrient transition metals in a time series of hydrothermal vent fluids from Main Endeavour Field, Juan de Fuca Ridge, Pacific Ocean
Nutrient transition metals in a time series of hydrothermal vent fluids from Main Endeavour Field, Juan de Fuca Ridge, Pacific Ocean
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DOI：
10.1016/j.epsl.2022.117943
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发表时间：
2023-01
影响因子：
5.3
通讯作者：
G. Evans;W. Seyfried;Chunyang Tan
中科院分区：
文献类型：
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作者：
G. Evans;W. Seyfried;Chunyang Tan
有电缆的深海观测站可以向海底仪器和取样装置提供持续的电力和通信连接。在这一能力的基础上，最近利用与加拿大海洋网络NEPTUNE观测站相连的新型远程触发喷口流体采样系统，从Juan de Fuca海岭（太平洋东北部）上经过充分研究的Main Endeavour Field收集了热液喷口流体的9个月时间序列（Seyfried等人，2022年）。这些样品的镁浓度非常低（镁= 0.19-3.07 mmol/kg），表明几乎没有受到周围海水的污染，为深入了解海底热液过程提供了极好的视角。在这里，我们提出了这些样品中的过渡金属（V，Cr，Mn，Fe，Co，Ni，Cu，Zn，Mo，Cd和W）的生物营养素的分析，并确定可能的控制processes.Overall，在收集的样品中的营养过渡金属浓度反映了动态响应的微妙的深层和近地表的变化在热液系统。部署大约两个月后，富含镁和硫酸盐的流体的混合与观察到的喷口流体温度变化无关，但与流体Co和Mo浓度的显着下降相一致，这可能表明系统的微妙或更深层的冷却和这些温度敏感金属的地下沉积。几个月后，喷口流体温度在20小时内从304 °C下降到280-285 °C，同时伴随着Cu、Zn和Cd浓度下降90%以上，以及Mo的额外下降，这可能是由于金属硫化物的沉淀，可能是在浅层地下。其他金属（V，Cr，Mn，Ni，W）的浓度相对稳定，表明更深层次的高温控制，虽然从喷口流体温度解耦的Cr和Ni浓度的协变表明微妙的，随时间变化的岩性控制。钼的浓度（29-220纳摩尔/千克）高于根据以前对海底热液喷口流体的分析得出的预期值，并不反映现代富钼海水的污染。这一发现对理解热液Mo向海洋的输送具有影响，与缺氧和Mo贫海洋环境中早期生命形式中Mo依赖生物途径的进化有关，这些生物途径被认为在整个太古宙普遍存在。
Cabled deep-sea observatories can deliver continuous power and communications linkages to seafloor instruments and sampling devices. Building on this capability, a nine-month time series of hydrothermal vent fluids was recently collected from the well-studied Main Endeavour Field on the Juan de Fuca Ridge (northeast Pacific Ocean) using a novel remotely triggered vent fluid sampling system connected to Ocean Network Canada's NEPTUNE observatory (Seyfried et al., 2022). These samples exhibit very low Mg concentrations (Mg = 0.19–3.07 mmol/kg), indicative of little-to-no contamination by ambient seawater, providing excellent insight into sub-seafloor hydrothermal processes. Here, we present analyses of these samples for transition metals identified as biological nutrients (V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Cd, and W) and identify possible controlling processes.Overall, nutrient transition metal concentrations in collected samples reflect dynamic responses to subtle deep-seated and near-surface changes in the hydrothermal system. Roughly two months into the deployment, inmixing of a Mg- and sulfate-rich fluid is decoupled from observed changes in vent fluid temperature but coincides with noticeable decreases in fluid Co and Mo concentrations, likely indicating subtle or more deep-seated cooling of the system and subsurface deposition of these temperature-sensitive metals. Several months later, a ∼20 °C drop in vent fluid temperature from 304 °C to 280–285 °C over ∼20 hours is accompanied by ∼90% decreases in Cu, Zn, and Cd concentrations and an additional decrease in Mo attributable to precipitation of metal sulfides, presumably in the shallow subsurface. Relative stability in concentrations of other metals (V, Cr, Mn, Ni, W) suggests more deeply seated higher-temperature controls, though covariations in Cr and Ni concentrations decoupled from vent fluid temperature suggest subtle, temporally variable lithologic controls. Molybdenum concentrations (29–220 nmol/kg) are higher than expected based on previous analyses of seafloor hydrothermal vent fluids and do not reflect contamination by modern Mo-rich seawater. This finding has implications for understandings of hydrothermal Mo delivery to the ocean, relevant to hypotheses about the evolution of Mo-dependent biological pathways among early life forms in anoxic and Mo-poor ocean environments thought to be prevalent throughout the Archean Eon.