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东南太平洋海隆（S EPR）部分是全球洋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大洋中脊（莫尔）系统中热液活动最强烈的区域，这反映在喷发点和水柱羽流的密度上。法国和日本/美国（PMEL NOAA）最近对这一地区的潜水器和水面船只访问表明，在14世纪50年代和18世纪40年代之间，热液羽状物覆盖了60%以上的脊顶。此外，喷口流体化学性质的显著变化导致羽流沃茨中的独特和不寻常的特征。强烈的，几乎连续的，和动态的性质的热液系统在这一节的SEPR提供了最集中的影响，任何地方的全球海脊系统对海洋地球化学和生物圈。 该系统的热液喷口和羽流的研究工作将继续与两个NSF资助的合作项目。M. Lilley、K.Von Damm和J.卢普顿已获得资助，在S EPR上执行一项25潜的潜水计划，重点是从17 ° S以南几个有记录的喷口区域收集喷口流体。R. Collier已获得资助，以便将对热液喷口特征的潜水观测扩大到局部（喷口区）至分段尺度的水柱热液羽流。此外，日本/太平洋海洋环境实验室海洋大气管理局正在继续对加勒特以南沿EPR轴的热液喷口/羽流沿着的分布和组成进行跨学科的联合调查。 将与上述资助的方案合作，对强烈的S EPR热液羽流的地质微生物学进行研究。本提案的目标是高度互补的，并将扩大资助Lilley/Collier计划的主要目标;这些研究将评估微生物种群的变化率和不断变化的羽流中的生物地球化学过程。与日本/太平洋海洋环境实验室-诺阿（海脊通量）S EPR项目的合作将能够确定某些相同地点的代表性热液矿物和有机碳垂直通量，并将这些通量与热液成分的地球化学转化率和含金属沉积物的分布和积累率联系起来。对转化过程和通量率的分析和解释将与M。Lilley（UW）（和K.Von Damm和J.卢普顿），R. Collier（OSU），Japanese（T.Urabe，J. Ishibashi，H. Kawahata，K. Marumo，A. Marnyarna及其同事）和PMEL /NOAA（E.贝克河Feely，G. Massoth，D. Butterfield和他的同事）科学家。

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.