Collaborative Research: Microbial Communities at the Cariaco Redox Interface: Coupling of Sulfur, Carbon and Metal Cycles

合作研究：卡里亚科氧化还原界面的微生物群落：硫、碳和金属循环的耦合

• 批准号: 0347811
• 负责人: Gordon Taylor
• 金额: --
• 依托单位: SUNY at Stony Brook
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0347811&HistoricalAwards=false
• 关键词: Collaborative; Research; Microbial; Communities; Cariaco

Project summaryThe interface between oxic and anoxic environments plays an important role in cycling of many elements in the ocean, particularly those with several redox states, including carbon, sulfur, nitrogen manganese and iron. The interface lies within a redox transition zone where reduced (sulfide, reduced metals, organic) and oxidized (oxygen, nitrate, metal oxides) chemical species coexist in opposing concentration gradients. Many important reactions in the transition zone are biologically mediated (e.g., sulfide oxidation and MnO2 reduction) and these reactions support microbial populations unable to exist anywhere else. The Cariaco Basin is the world's second largest pelagic anoxic systems and is the only large, truly marine, permanently anoxic basin. It is also the site of the international CARIACO (CArbon Retention In A Colored Ocean) time series program, which is examining long-term variability in ocean productivity and sedimentation. The major long term goal of this project is discovering and characterizing yet undescribed microorganisms in the redox transition zone of the Cariaco Basin at the CARIACO time series site, and laying groundwork for understanding their significance in carbon, sulfur and metal cycling. The following experimental objectives are being pursued: 1. Describing the prokaryotic community with the highest feasible vertical resolution within the redox transition zone using 16S rRNA libraries/T-RFLP or DGGE techniques; 2. Designing oligonucleotide probes targeting specific groups of prokaryotes in each of the three microbial guilds (aerobic, microaerophilic and anaerobic) on the basis of 16S rDNA libraries. Using fluorescent in situ hybridization with these probes (FISH) and samples collected during first two years of the project to test whether prokaryotes found in 16S rDNA libraries/DGGE gels are numerically dominant within their respective guilds; 3. Identifying autotrophic components of the three guilds using a combination of 14C autoradiography with in situ hybridization; 4. Characterizing the three guilds by the diversity of ribulose-1,5-bisphosphate carboxylase/oxygenase and citrate liase genes; 5. Producing concentration profiles of sulfide, thiosulfate, sulfite, elemental sulfur, MnII and MnO2, dissolved and particulate Fe, and FeS to interpret possible biogeochemical properties of these Cariaco guilds; 6. Isolating prokaryotes with novel types of metabolism--chemoautotrophs oxidizing sulfide and thiosulfate using manganese oxide or iron oxide/hydroxide as electron acceptors and creating enrichment cultures of other metabolisms: (a) aerobic sulfide oxidizers, (b) (micro)aerophilic metal oxidizers, (c) anaerobic denitrifying sulfide oxidizers, (d) anaerobic MnO2/S0 reducers (Geobacteraceae and physiologically similar bacteria) and (e) S0 and sulfite/thiosulfate disproportionating bacteria; 7. Identifying enrichment (or pure) cultures by FISH with probes designed from 16S rDNA libraries. 16S rDNA and CO2 fixing genes from these isolates are being compared to the molecular information (16S rDNA, CO2 fixing genes, FISH) from their respective guilds to validate their importance in nature. Physiological properties of isolated bacteria are being studied for their ability to grow on potential electron donors, acceptors, and sources of carbon. This project includes a substantial educational component, an international collaboration with Venezuelan scientists (Simon Bolivar University and Fundacion La Salle de Ciencias Naturales) and close collaboration with the ongoing CARIACO project funded by NSF. At least two graduate students and two undergraduates are being trained during the course of the project. Collaboration with one of the leading Latin American institutions is offering continuing opportunities to recruit students of Venezuelan origin and opportunities for forming formal collaborations.

项目总结，氧和缺氧环境之间的界面在海洋中许多元素的骑自行车中起着重要作用，尤其是那些具有多种氧化还原状态的元素，包括碳，硫，氮锰和铁。该界面位于氧化还原过渡区内，在该区域中，氧化（硫化物还原，有机）和氧化（氧，硝酸盐，金属氧化物）化学物质在相对浓度梯度中共存。过渡区的许多重要反应是生物学介导的（例如，硫化物氧化和MNO2还原），这些反应支持微生物种群在其他任何地方都无法存在。 Cariaco盆地是世界第二大的上层缺氧系统，是唯一的大型，真正的海洋，永久性的缺氧盆地。它也是国际Cariaco（彩色海洋中的碳保留）时间序列计划的地点，该计划正在研究海洋生产力和沉降的长期变化。 该项目的主要长期目标是在Cari​​aco Time系列地点发现和表征Cariaco Basin的氧化还原过渡区中未描述的微生物，并为了解它们在碳，硫和金属循环中的重要性而奠定了基础。正在实现以下实验目标：1。描述使用16S rRNA库/t-rflp或DGGE技术在氧化还原过渡区内具有最高可行垂直分辨率的原核群落； 2。设计寡核苷酸探针，针对三个微生物行会（有氧，微生物粒细胞和厌氧菌）中的每个原核生物的特定组。使用这些探针（FISH）的荧光原位杂交以及在项目的前两年收集的样品，以测试在16S rDNA文库/DGGE凝胶中是否在各自的公会中数值占主导地位的原核生物； 3。使用14C自显影和原位杂交的组合来识别三个公会的自养分子成分； 4。通过核糖1,5-双磷酸羧化酶/氧酶和柠檬酸盐联络基因的多样性来表征这三个公会； 5。产生硫化物，硫代硫酸盐，亚硫酸盐，元素硫，MNII和MNO2的浓度谱，溶解和颗粒化Fe，以及FES来解释这些Cariaco guilds的生物地球化学特性； 6. Isolating prokaryotes with novel types of metabolism--chemoautotrophs oxidizing sulfide and thiosulfate using manganese oxide or iron oxide/hydroxide as electron acceptors and creating enrichment cultures of other metabolisms: (a) aerobic sulfide oxidizers, (b) (micro)aerophilic metal oxidizers, (c) anaerobic硝化硫化物氧化剂，（d）厌氧MNO2/S0还原剂（地球杆菌科和生理上相似的细菌）和（E）S0和硫酸盐/硫代硫酸盐/硫代硫酸盐不成比例的细菌； 7。通过鱼类探针从16S rDNA文库设计的探针来鉴定富集（或纯）培养物。 将这些分离株的16S rDNA和二氧化碳固定基因与分子信息（16S rDNA，二氧化碳固定基因，鱼类，鱼）进行了比较，以验证其在自然界中的重要性。正在研究分离细菌的生理特性，以在潜在的电子供体，受体和碳源来源上生长它们的能力。该项目包括与委内瑞拉科学家（Simon Bolivar University和Fundacion La Salle de Ciencias Naturals）的国际合作，以及与NSF持续的Cariaco Project的密切合作。 在项目过程中，至少有两名研究生和两名本科生正在接受培训。 与拉丁美洲领先的机构之一的合作正在提供持续的机会，以招募委内瑞拉起源的学生以及建立正式合作的机会。