An integrated study of seepage through the seabed of the Nile deep-sea fan

在大陆边缘，流体和气体通过海底排放到海洋中。排放的形式从通过海底的扩散流延伸到通过渗漏和通风口的集中流，并且在时间和空间上可以高度可变。流体渗漏是地质圈、生物圈、水圈和大气相互联系的高度动态的场所。渗漏液体(液体和气体)除水外，还包括碳氢化合物、二氧化碳、氮气和硫化氢。这些能源支持不同的生物群落和化学合成有机体。目前，被动大陆边缘流体渗漏的全球库存正在迅速增加，但在这些流体渗漏处运行的地质、化学和生物过程仍然鲜为人知。在这方面，重要的研究任务是得出甲烷通量与气候变化的相关性，评估大陆斜坡上流体触发的不稳定性，以及在近海深处进行碳氢化合物化探。MEDIFLUX建议对尼罗河深海扇这一被动大陆边缘上典型地富含各种流体逃逸结构的地点的流体渗漏进行全面、跨学科的调查。目的是(1)描述尼罗河深海扇流体渗漏的地理分布、类型、地质形成和活动，(2)确定流出流体的组成，并利用这些信息推断流体性质和深部流体过程，(3)了解渗漏生物群对化学元素迁移和分解的控制和机制，并获得在流体渗漏处元素循环和输出的有限预算。

At continental margins fluid and gases are emitted into the ocean via the seafloor. The forms of emissions extend from diffusive flow through the seafloor, to focussed flow through seeps and vents, and can be highly variable in time and space. Fluid seeps are highly dynamic sites where geosphere, biosphere, hydrosphere and atmosphere are linked. Seep fluids (liquids and gases) include hydrocarbons, carbon dioxide, nitrogen and hydrogen sulfide, in addition to water. These energy sources support distinct biological communities and chemosynthetic organisms. Currently, the global inventory of fluid seeps at passive continental margins is growing rapidly, but geological, chemical and biological processes operating at those fluid seeps remain little known. In this regard, important research tasks are deriving methane fluxes in their relevance to climatic changes, evaluation of fluid-triggered instabilities on continental slopes, and hydrocarbon geochemical prospecting in the deep offshore. MEDIFLUX proposes a comprehensive, transdisciplinary investigation of fluid seepage at a site exemplarily rich in a large variety of fluid escape structures on a passive continental margin, the Nile deep-sea fan. Objectives are (1) to describe the geographical distribution, types, geological formation and activity of fluid seeps of the Nile deep-sea fan, (2) to determine the composition of emitted fluids and use this information to infer fluid properties and fluid processes at depth, (3) to understand the controls and mechanisms of chemical element transport and breakdown by seep biota, and to obtain a well constrained budget of element cycling and export at fluid seeps.