Collaborative Research: Direct Sampling of the Oceanic Sub-Surface Biosphere at Old and Young Seamounts

合作研究：老海山和新海山海洋地下生物圈的直接采样

• 批准号: 0085615
• 负责人: Harlan Johnson
• 金额: $ 75.82万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-11-01 至 2006-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0085615&HistoricalAwards=false
• 关键词: Collaborative; Research; Direct; Sampling; Oceanic

COLLABORATIVE LEXEN RESEARCH: DIRECT SAMPLING OF THE OCEANIC SUB-SURFACE BIOSPHERE AT OLD AND YOUNG SEAMOUNTSOceanic crust is a plausible but unproven habitat for a microbial biosphere of planetary proportions. The upper 500 meters of igneous basement is warm, porous and permeable, forming a global-scale aquifer hosting the circulation of nutrient-rich hydrothermal fluids. Heat from the lower intrusive crustal rocks drives fluid convection cells within this aquifer, even in crust many tens of millions of years old. This thermal convection is strongly modulated by tidal forces, increasing fluid velocities and stirring the sub-surface incubator more vigorously than previously believed. Two unique methods will be used for sampling uncompromised crustal fluids from two contrasting hydrothermal areas on the Juan de Fuca Ridge. Axial Seamount is currently forming directly on the ridge axis, with recent eruptions on the summit and flanks, and has considerable geological and surface biological variability with periods of less than a year. At Axial caldera a sampling facility with a re-entry cone was cemented directly to the seafloor in 1998, providing uncontaminated access to a 50 degrees C diffuse vent. In contrast, Baby Bare (BB) Seamount sits on 3.5 My crust east of the ridge axis, with a small exposed summit of altered rock completely surrounded by low permeability sediments. This project will sample Baby Bare fluids (40 degrees C) below the water/rock interface, using a newly developed break-away coring instrument to insert a 3-meter long titanium tube into the sub-surface, below the biologically active surface zone. The samples obtained from both Axial and Baby Bare will be studied for the entire spectrum of bacteria and archea populations, the fluids will be analyzed for their inorganic and organic chemistry, and the data placed in their full environmental context using temperature and fluid flow measurements. This project attempts to integrate for the first time inorganic and organic chemistry with geophysical parameters including porosity and fluid flow rates, so as to better understand the microbial ecology of these sub-surface biotopes. By examining the chemical and microbial ecology and energetics of the sub-surface, and particularly the sub-surface associated with hydrothermal systems, a framework for studying the prospects of extraterrestrial life may be developed.

LEXEN 合作研究：在老海山和新海山对海洋地下生物圈进行直接采样海洋地壳是行星比例的微生物生物圈的一个看似合理但未经证实的栖息地。火成岩基底上部 500 米温暖、多孔且可渗透，形成全球范围内的含水层，承载着营养丰富的热液循环。来自较低侵入地壳岩石的热量驱动该含水层内的流体对流细胞，甚至在数千万年前的地壳中也是如此。这种热对流受到潮汐力的强烈调节，增加了流体速度并比之前认为的更剧烈地搅拌地下培养箱。将使用两种独特的方法从胡安德富卡海岭的两个对比鲜明的热液区域对未受损的地壳流体进行采样。轴海山目前直接在山脊轴上形成，最近在山顶和侧翼喷发，并且具有相当大的地质和表面生物变化，周期不到一年。 1998 年，在 Axial 破火山口，带有重返锥体的采样设施直接固定在海底，为 50 摄氏度的扩散口提供了不受污染的通道。相比之下，Baby Bare (BB) 海山位于海脊轴以东的 3.5 My 地壳上，有一小片裸露的蚀变岩山顶，完全被低渗透性沉积物包围。该项目将对水/岩石界面下方的 Baby Bare 流体（40 摄氏度）进行采样，使用新开发的分离式取芯仪器将 3 米长的钛管插入生物活性表面区域下方的地下。从 Axial 和 Baby Bare 获得的样本将用于研究整个细菌和古细菌种群，将分析流体的无机和有机化学成分，并使用温度和流体流量测量将数据置于完整的环境背景中。该项目试图首次将无机和有机化学与包括孔隙度和流体流速在内的地球物理参数相结合，以便更好地了解这些地下生境的微生物生态。通过检查地下，特别是与热液系统相关的地下的化学和微生物生态以及能量学，可以开发一个研究外星生命前景的框架。