A SGER Proposal to Test the Hypothesis of a Sub-Surface Biosphere within Oceanic Crust

检验洋壳内地下生物圈假说的 SGER 提案

• 批准号: 9817616
• 负责人: James Cowen
• 金额: $ 3.36万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-15 至 2000-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9817616&HistoricalAwards=false
• 关键词: SGER; Proposal; Test; Hypothesis; Sub

Cowen/Johnson AbstractThe primary goal for our LEXEN program is to test the hypothesis that there is a substantial microbial biosphere within oceanic crust. A critical component of this study is to learn how this biosphere varies under different crustal-geothermal regimes, and how the organic carbon evidence of the sub-surface microbial activity is manifested at sites of widely different crustal age and sediment cover. We will be determining the processes that control the distribution of life within the crust, specifically within (a) young crust with high temperature fluids vs old crust with warm fluids, (b) sedimented vs un-sedimented crustal sections, oxygenated crustal fluids vs anoxic fluids, and (d) long fluid residence times vs short residence times. A plausible answer to the question regarding the existence of a sub-surface biosphere requires that we characterize the source fluids in terms of their organic composition and microbial taxonomy (lipids and molecular genetic probes), identify the fluid transit paths, the depth of fluid circulation and residence times in order to determine the area/volume of the crustal rocks that we are sampling. Finally, it is important that we make a first-order estimate of how globally we can extrapolate our results, by comparison of data from both old and young sites at the same spreading center.

Cowen/Johnson 摘要我们 LEXEN 计划的主要目标是检验洋壳内存在大量微生物生物圈的假设。 这项研究的一个关键组成部分是了解该生物圈在不同的地壳地热状况下如何变化，以及地下微生物活动的有机碳证据如何在地壳年龄和沉积物覆盖差异很大的地点表现出来。 我们将确定控制地壳内生命分布的过程，特别是（a）具有高温流体的年轻地壳与具有温暖流体的古老地壳，（b）沉积地壳部分与未沉积地壳部分，含氧地壳流体与缺氧流体，以及（d）长流体停留时间与短停留时间。 关于地下生物圈存在问题的合理答案要求我们根据源流体的有机组成和微生物分类学（脂质和分子遗传探针）来表征源流体，确定流体传输路径、流体循环深度和停留时间，以确定我们正在采样的地壳岩石的面积/体积。 最后，重要的是，我们通过比较同一传播中心的旧站点和新站点的数据，对如何在全球范围内推断我们的结果进行一阶估计。