LEXEN: Development of Capability to Measure Proxies of Microbial Activity within Oceanic Crust (Collaborative Research)

LEXEN：开发测量洋壳内微生物活动指标的能力（合作研究）

• 批准号: 9729672
• 负责人: Stephen Giovannoni
• 金额: $ 5.49万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-10-01 至 2000-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9729672&HistoricalAwards=false
• 关键词: LEXEN; Development; Capability; Measure; Proxies

9729672 Giovannoni This research suggests a program to test the hypothesis that there is a substantial microbial biosphere living within the oceanic upper crustal rocks of the off-axis ridge flanks, hundreds of meters below the water-rock interface, by detecting specific metabolic products which are associated with these sub-surface microbial communities. These diagnostic organic compounds should accompany the hydrothermal fluid that is known to circulate within the upper crustal rocks and eventually discharges into the overlying seawater at diffuse vent sites in exposed rock outcrops. We will also detect and phylogeneticallv characterize (ribosomal RNA molecular probe) any cellular biomass associated with fluid discharges. To test the ridge flank subsurface biosphere hypothesis, we propose to build an instrumented "bio-blanket" that focuses up-welling fluid emanating from these diffuse vent areas through relatively small scavenging columns that serve as traps for metabolic (organic carbon) products. The proposed instrumented blanket would also measure up-welling temperatures and velocities as the hydrothermal fluid vents into seawater. The development of the bio-blanket will be in several stages: initial instrument-component tests and fluid sampling will exploit the convenient valved- plumbing system of the "corked" ODP Hole 1026B, which has documented 65 C outflowing fluids; subsequent complete prototype instruments will be deployed over active diffuse vents at both an exposed outcrop at a ridge flank site (Baby Bare, Cascadia Basin) and a mid-ocean ridge spreading center (Endeavour Segment), where flux rates are high and the signal-to-noise ratio of any component of the fluid is quite large. The direct detection of a wide-spread biological community, living within the sub-surface ocean floor in the older ridge flank regions, would dramatically alter our estimates of biological productivity and the global carbon budgets, and have a profound impact on o ur philosophical view of the earth. ***

9729672 Giovannoni这项研究提出了一个程序来测试假设，即有大量的微生物生物圈生活在离轴脊侧翼的海洋上地壳岩石中，在水-岩石界面下方数百米处，通过检测与这些地下微生物群落相关的特定代谢产物。 这些诊断性有机化合物应该伴随着已知在上地壳岩石内循环的热液流体，并最终在裸露岩石露头的扩散喷口处排入上覆海水。 我们还将检测和遗传学表征（核糖体RNA分子探针）与液体排放相关的任何细胞生物量。 为了测试脊侧翼地下生物圈的假设，我们建议建立一个仪表化的“生物毯”，集中从这些扩散喷口地区通过相对较小的清除柱，作为陷阱的代谢（有机碳）产品的上涌流体。 拟议的仪器包层还将测量热液排入海水时的上升温度和速度。 生物层的开发将分几个阶段进行：最初的仪器部件测试和流体取样将利用“塞住”ODP孔1026 B的方便的阀门管道系统，该孔记录了65 C的流出流体;随后，将在活动扩散喷口上部署完整的原型仪器，（卡斯卡迪亚盆地的Baby Bare）和大洋中脊扩张中心（奋进段），在那里，流量率很高，流体任何成分的信噪比都相当大。 直接探测到生活在较老的海脊侧翼区域的海底下的广泛分布的生物群落，将极大地改变我们对生物生产力和全球碳预算的估计，并对我们对地球的哲学观点产生深远的影响。 ***