Ride Integrated Studies at 9degN East Pacific Rise: Establishing a Role for Fe and S Microbial Metabolism in Ocean Crust Weathering

北纬 9 度东太平洋海隆的综合研究：确定铁和硫微生物代谢在洋壳风化中的作用

• 批准号: 0241791
• 负责人: Katrina Edwards
• 金额: $ 38.58万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-04-01 至 2006-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0241791&HistoricalAwards=false
• 关键词: Ride; Integrated; Studies; 9degN; East

This integrated field and laboratory studies is investigating the role of chemosynthetic microbial communities in ocean crust alteration and biomass production in the deep-sea. The studies are based on preliminary studies concerning the early stages of ocean crust weathering and fluid-rock interactions in the shallow sub-seafloor. The principal hypothesis tested in this project is that the activities of autotrophic Fe- and S-oxidizing prokaryotes play important roles in the initial colonization and weathering of ocean crust. This process results in: 1) the development of sharp redox gradients associated with the surface crustal rock (seafloor-exposed surfaces, or subseafloor surfaces exposed to circulating fluids along fractures), and 2) a flux of fresh organic C (Corg) to ridge flanks that may be used for respiration by endolithic heterotrophic (including Fe- and S-reducing) prokaryote communities. These communities likely play a role in the development of secondary alteration zones rich in reduced Fe and S mineral phases (pyrite, magnetite), but their role in promoting crustal weathering is not yet known, and is being investigated in this project. The research has four principal components: 1. Using culture-dependent and culture-independent methods, examining the phylogenetic and physiologic diversity of endolithic Fe and S microorganisms associated with the early stages of ocean crust weathering (field-based). 2. Using geochemical techniques (elemental and isotopic), examining the progressive weathering of ocean crust along weathering rinds; correlate finding with (1) (field-based). 3. Conducting field-incubation studies for 6 mo. to 1 yr. using a suite of pre-characterized natural crust material (basaltic glass, basalt, varying compositions). Analyze according to (1) and (2). 4. Conducting laboratory experiments using existing and anticipated new strains of Fe and S microorganisms exploring the kinetic relationships between crust alteration and biomass production, and to determine elemental portioning and speciation effects attributable to biology. The fieldwork is based on two cruises: one cruise to EPR scheduled for Spring 03 (OCE-9819261, Drs. Fornari, Tivey, and Schouten, PI.s), and a second cruise to return to the same region 6-12 mo. later. The first cruise initiated field incubation experiments and collected some preliminary samples along transects at 9degreeN on basalt flows, of ages from ~0-20,000 yrs. The purpose of the follow-up cruise is to collect the field incubation samples and to collect fresh environment samples in a controlled manner that insures biological integrity of the material.

这项综合的现场和实验室研究正在调查化学合成微生物群落在洋壳变化和深海生物量生产中的作用。这些研究基于有关洋壳风化早期阶段和浅海底流体-岩石相互作用的初步研究。 该项目测试的主要假设是自养铁和硫氧化原核生物的活动在洋壳的初始定殖和风化中发挥重要作用。 这一过程导致：1）与地壳岩石表面（暴露于海底的表面，或暴露于沿裂缝的循环流体的海底表面）相关的急剧氧化还原梯度的发展，以及2）新鲜有机碳（Corg）流向山脊侧面，可用于内生异养（包括铁和硫还原）原核生物群落的呼吸。 这些群落可能在富含还原铁和硫矿物相（黄铁矿、磁铁矿）的次生蚀变带的发育中发挥了作用，但它们在促进地壳风化中的作用尚不清楚，并且正在本项目中进行研究。 该研究有四个主要组成部分： 1. 使用培养依赖和独立于培养的方法，检查与洋壳风化早期阶段相关的内生铁和硫微生物的系统发育和生理多样性（基于现场）。 2. 使用地球化学技术（元素和同位素），检查洋壳沿风化层的渐进风化；将发现与 (1) 相关联（基于现场）。 3. 进行为期6个月的实地孵化研究。至 1 岁使用一套预先表征的天然外壳材料（玄武岩玻璃、玄武岩、不同成分）。 根据(1)、(2)分析。 4. 使用现有的和预期的新铁和硫微生物菌株进行实验室实验，探索地壳蚀变和生物量生产之间的动力学关系，并确定生物学引起的元素分配和物种形成效应。 实地工作基于两次巡航：一次计划于 03 年春季前往 EPR（OCE-9819261，Fornari、Tivey 和 Schouten，PI.s 博士），第二次巡航将于 6-12 个月返回同一地区。之后。 第一次巡航启动了现场孵化实验，并沿着北纬 9 度的玄武岩流横断面收集了一些初步样本，年龄从约 0-20,000 年不等。 后续巡航的目的是收集现场孵化样品并以受控方式收集新鲜环境样品，以确保材料的生物完整性。