Development of the Capability to Measure Proxies of Microbial Activity Within Oceanic Crust

这项合作技术开发项目将由夏威夷大学、华盛顿大学和伊利诺斯-芝加哥大学的研究人员进行。专门的海底仪器将被开发出来，通过检测伴随热液从地壳排放到上面的海水中的特定代谢产物，来测试水-岩石界面以下数百米的海底生物圈的存在。为了测试地下生物圈假说，将建造和部署一个仪器化的“生物毯”，将一小块地表岩石与海水隔离开来，并通过清除柱集中上涌的流体，这些清除柱作为与这些地下微生物群落相关的代谢（有机碳）产物的陷阱。这些诊断性有机化合物应该伴随着热液流体，这些热液流体已知在上部地壳岩石中循环，并最终在暴露的岩石露头的扩散喷口处排放到上覆的海水中。拟议中的仪器毯还将测量流体流入海水时上涌的温度和速度。生物膜的开发将分几个阶段逐步进行，最初部署将在一个山脊轴进行，那里的流体通量大，溶解碳代谢浓度相对较高。直接探测到生活在海底下的广泛分布的生物群落，将极大地改变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。

This collaborative technology development project will be undertaken by investigators at the Universities of Hawaii, Washington, and Illinois-Chicago. Specialized seafloor instrumentation will be developed to test for the presence of a sub-seafloor biosphere hundreds of meters below the water-rock interface, by detecting specific metabolic products which accompany the hydrothermal fluids as they vent from the crust into the overlying seawater. To test the sub-surface biosphere hypothesis, an instrumented "bio- blanket" will be built and deployed that isolates a small area of surface rock from seawater, and focuses up-welling fluid through scavenging columns that serve as traps for metabolic (organic carbon) 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. The proposed instrumented blanket would also measure up-welling temperatures and velocities as the fluid vents into seawater. The development of the bio-blanket will be in several graduated stages, with the initial deployments being carried out at a ridge axis, where the fluid flux levels are substantial, and the dissolved carbon metabolic concentrations are relatively high. The direct detection of a wide-spread biological community, living within the sub-surface ocean floor would dramatically alter estimates of biological productivity and the global carbon budgets, and have a profound impact on our philosophical view of the earth.