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

合作研究：老海山和年轻海山海洋地下生物圈的直接采样

• 批准号: 0315150
• 负责人: Matthew McCarthy
• 金额: $ 4.03万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-01-01 至 2004-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0315150&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.

合作的Lexen研究：在年老的和年轻的SEAMOUNT对海洋次表层生物圈进行直接采样海洋地壳是一个看似合理但未经证实的微生物生物圈的栖息地，其规模相当于行星。上部500米的火成岩基底温暖、多孔、可渗透，形成了全球规模的含水层，承载着营养丰富的热液流体的循环。来自下部侵入地壳岩石的热量驱动着含水层内的流体对流单元，即使是在几千万年前的地壳中也是如此。这种热对流受到潮汐力量的强烈调制，增加了流体的速度，并比之前认为的更有力地搅动了地下孵化器。将使用两种独特的方法从胡安德富卡山脊上两个不同的热液区域采集未受影响的地壳流体样本。轴向海山目前直接在山脊轴线上形成，最近在山顶和侧翼喷发，具有相当大的地质和表面生物变异性，周期不到一年。1998年，在Axial Caldera，一个带有再入锥体的采样设施被直接粘合到海底，提供了通往50摄氏度扩散喷口的无污染通道。相比之下，婴儿裸露(BB)海山位于山脊轴线以东3.5我的地壳上，有一个小的裸露的蚀变岩石山顶，完全被低渗透性沉积物包围。该项目将对水/岩石界面下的婴儿裸露液体(40摄氏度)进行采样，使用新开发的分离取芯仪器将一根3米长的钛管插入地下，位于生物活跃的表层之下。从Axial和Baby Bare获得的样本将被研究细菌和古细菌种群的整个光谱，流体将被分析其无机化学和有机化学，并使用温度和流体流量测量将数据放置在其完整的环境中。该项目试图首次将无机化学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，以更好地了解这些地下生物区的微生物生态。通过研究次表层，特别是与热液系统有关的次表层的化学、微生物生态和能量学，可以建立一个研究地外生命前景的框架。