S-EPR: Biogeochemical Evolution in Intense Hydrothermal Plumes Emanating from a Superfast Spreading Center

在加勒特变换和复活节微板块之间的南东太平洋隆起（S EPR）是全球脊系统中扩张速度最快的区域之一，也是迄今为止研究的所有海洋中脊（MOR）系统中最强烈的热液活动的所在地，这反映在喷口位置的密度和水柱羽流中。最近，法国和日本/美国（PMEL NOAA）对该地区的潜水器和水面船进行了访问，发现热液羽流覆盖了14Ý50' s和18Ý40' s之间脊峰的60%以上。此外，急剧变化的喷口流体化学物质导致羽流水域明显且不寻常的特征。南太平洋寒带这一段的热液系统的强烈、几乎连续和动态的性质为全球脊系统对海洋地球化学和生物圈的任何地方提供了最集中的影响。该系统的热液喷口和羽流的研究工作将由两个NSF资助的合作项目继续进行。M. Lilley、K.Von Damm和J. Lupton已获得资助，在S EPR上进行25次潜水计划，重点收集17ÝS以南几个有记录的喷口区域的喷口流体。资助R. Collier将水下热液喷口特征观测扩展到局部（喷口场）的水柱热液柱至分段尺度。此外，日本/PMEL国家海洋和大气管理局正在继续他们的联合，跨学科的研究热液喷口/羽流沿加勒特以南的EPR轴的分布和组成。在上述资助项目的合作下，将进行一项强烈的S - EPR热液羽流的地球微生物学研究。本提案的目标高度补充并将扩展利利/科利尔项目的主要目标；这些研究将评估演化羽流中微生物种群和生物地球化学过程的变化率。与日本/PMEL- NOAA (RIDGE Flux) S EPR项目的合作将能够确定一些相同地点的代表性热液矿物和有机C垂直通量，并将这些通量与热液成分的生物地球化学转化速率和含金属沉积物分布和积累速率联系起来。转化过程和通量速率的分析和解释将在与M. Lilley (UW)（以及K. von Damm和J. Lupton）、R. Collier （OSU）、日本（T.Urabe、J. Ishibashi、H. Kawahata、K. Marumo、A. Marnyarna及其同事）和PMEL /NOAA （E. Baker、R. Feely、G. Massoth、D. Butterfield及其同事）科学家的密切合作下完成。

The section of the southern East Pacific Rise (S EPR) between the Garrett Transform and the Easter Microplate has one of the fastest spreading rates on the global ridge system and is the locus of the most intense hydrothermal activity, reflected in the density of venting sites and in the water column plumes, of all mid-ocean ridge (MOR) systems studied to date. Recent submersible and surface ship visits to this region by the French and Japanese/American (PMEL NOAA) have revealed that hydrothermal plumes overlay over 60% of the ridge crest between 14Ý50' and 18Ý40' S. Furthermore, dramatically variable vent fluid chemistries result in distinct, and unusual signatures in the plume waters. The intense, nearly continuous, and dynamic nature of the hydrothermal system over this section of the S EPR provides for the most focused impact anywhere of the global ridge system on the ocean geochemistry and biosphere. Research efforts focused on the hydrothermal venting and plumes of this system will continue with two NSF funded collaborative projects. M. Lilley, K.Von Damm, and J. Lupton have been funded to perform a 25 dive submersible program on the S EPR, focusing on the collection of vent fluds from several regions of documented venting south of 17ÝS. R. Collier has been funded to extend the submersible observations of the hydrothermal vent characteristics to the water column hydrothermal plume at the local (vent field) to segment scale. In addition, the Japanese/PMEL NOAA are continuing their joint, interdisciplinary investigation of the distribution and composition of hydrothermal venting/plumes along the EPR axis south of the Garrett. A study of the geomicrobiology of the intense S EPR hydrothermal plumes will be made in collaboration with the above funded programs. The goals of the present proposal are highly complementary to and will extend the primary goals of the funded Lilley/Collier programs; these studies will assess the rate of change of microbial populations and biogeochemical processes in an evolving plume. Collaboration with the Japanese/PMEL- NOAA (RIDGE Flux) S EPR project will allow the determination of representative hydrothermal mineral and organic C vertical fluxes at some of the same sites and to relate these fluxes to biogeochemical transformation rates of hydrothermal constituents and metalliferous sediment distributions and accumulation rates. Analyses and interpretation of transformation processes and flux rates will be completed in close collaboration with M. Lilley (UW) (and K.Von Damm and J. Lupton), R. Collier (OSU), Japanese (T.Urabe, J. Ishibashi, H. Kawahata, K. Marumo, A. Marnyarna, and colleagues) and PMEL /NOAA (E. Baker, R. Feely, G. Massoth, D. Butterfield and colleagues) scientists.