Collaborative Research: Structure, Function and Evolution of Authigenic, Methane-Derived Carbonate Ecosystems

合作研究：自生甲烷衍生碳酸盐生态系统的结构、功能和演化

• 批准号: 0825436
• 负责人: Anthony Rathburn
• 金额: $ 28.05万
• 依托单位: Indiana State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-10-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0825436&HistoricalAwards=false
• 关键词: Collaborative; Research; Structure; Function; Evolution

Authigenic carbonate precipitation associated with methane seepage is typically mediated by anaerobic oxidation of methane (AOM). This microbial process produces massive amounts of carbonate rock, introducing habitat heterogeneity to continental margins and providing a major repository for methane-derived carbon released from the sea floor. This study will investigate the extent to which these carbonate substrates form a distinct ecosystem within the seep environment by characterizing associated microbial, foraminiferal, macrofaunal and megafaunal communities in a successional context. Surveys and sampling of carbonate will take place at 4 bathyal locations on the Costa Rica margin (730-1300 m) and at Hydrate Ridge North on the Oregon margin (590 m). Location differences and associated water depth, oxygenation, seep megafauna and carbonate formation variation are expected to influence community composition. This study will characterize assemblages inhabiting carbonates subject to active, weak and no methane seepage, and conduct rock colonization and transplant experiments to address the following main hypotheses:(1) Under conditions of active seepage at the seafloor-water interface, authigenic carbonate functions as a distinct ecosystem fueled by AOM, with its own sources of (chemosynthetic) primary and secondary production; (2) Seep carbonate faunal communities undergo succession driven by methane supply and microbial activity; (3) Sessile seep carbonate assemblages include mainly microbial, protozoan and metazoan species that are taxonomically and evolutionarily distinct from the biota of surrounding seep sediments, but ecologically and evolutionarily related to deep-sea, hard-substrate and reducing faunas, including those from seeps, vents, coral mounds and whale bones. Single rocks will be split and sectioned for carbonate mineralogy and isotopic analysis, FISH-SIMS analyses of endogeneous microorganisms and their respective delta 13C signatures, faunal (protozoan and metazoan) taxonomic, lifestyle and position studies. Stable isotopic and lipid analyses of foraminifera and metazoan protoplasm, delta 18O and delta 13C signatures of foraminiferan tests and mollusk shells will be linked to microbial and carbonate signatures to assess trophic pathways and paleo proxies for methane release. Archaea and AOM are hypothesized as key to both. Defaunated carbonate substrates will be deployed at active and inactive sites for 1 year to examine early faunal succession and the role of external seepage. Rocks transplanted between inactive and active sites, with appropriate manipulation controls, will provide additional information about faunal reliance on seepage and persistence of AOM in the absence of seepage. Community comparisons will be drawn with seep sediments, other biotic substrates (mussels, clams, tubeworms) and with other deep-sea reducing and hardground systems (vents, whales, deep-water corals). Macrofaunal assemblages will be DNA and selected annelid and foraminiferan taxa will be targeted for phylogenetic analyses to assess evolutionary affinities with fauna from other hardground-reducing ecosystems (vents).Broader Impacts: Benefits of this research to society include: (1) an understanding of seep carbonate ecosystems for improved marine resource management and more comprehensive assessments of seafloor biodiversity, carbon cycling, and adaptations to extreme environments; and (2) a model for successional changes in carbonate ecosystems and the use of their faunas as proxies to more accurately assess past methane release and paleoclimate change. Education and outreach will include local school presentations; web site development and interdisciplinary, hands-on, at-sea training of future scientists at undergraduate, graduate, and post-doc levels, including under-represented groups (women; first-generation university students from rural communities) recruited through SURF, STARS and REU programs. Research results will be incorporated into lectures, exercises and field trips for deep-sea biology, microbiology, geology, paleontology, oceanography and benthic ecology courses, and onto websites and databases managed by the Census of Marine Life and the SIO Benthic Invertebrate Collection.

与甲烷渗漏相关的正质碳酸盐沉淀通常是由甲烷（AOM）的厌氧氧化介导的。这种微生物过程会产生大量的碳酸盐岩石，将栖息地异质性引入大陆边缘，并为从海底释放的甲烷衍生的碳提供了一个主要的存储库。这项研究将通过表征相关的微生物，有孔虫，大氟烟粉和巨型群落在渗水环境中在渗水环境中在渗水环境中形成独特的生态系统的程度。碳酸盐的调查和采样将在哥斯达黎加边缘（730-1300 m）的4个Bathyal位置进行，在俄勒冈州边缘（590 m）的水合​​山脊北部进行。预计位置差异和相关的水深度，氧合，渗透性巨型法和碳酸盐形成变化会影响社区组成。这项研究将表征居住的碳酸盐的组合，受到活跃，弱和无甲烷的渗透，并进行岩石殖民和移植实验，以解决以下主要假设：（1）在海底水界面上有效渗透的条件下（2）渗透碳酸盐动物群落经历甲烷供应和微生物活性驱动的继承； （3）连续渗透的碳酸盐组合主要包括微生物，原生动物和后代物种，它们在分类和进化上与周围的渗水沉积物的生物群不同，但在生态和进化上与深海，硬质，硬质和减少的faunas相关，包括来自Seeps，Vents，Vents，Coral coral of Coral and Whale and whale and Whale and whale and whale and whale and whale and whale and whale and whale and whale and whale and whale bons and whale bons and whale bons。单个岩石将被拆分并分割，用于碳酸盐矿物学和同位素分析，对内差微生物的鱼类SIMS分析及其各自的三角洲13C特征，Faunal（原生动物和后生动物）分类，生活方式和位置研究。有孔虫和后生原生质的稳定同位素和脂质分析，有孔虫测试的Delta 18O和Delta 13C特征和Mollusk壳的标志将与微生物和碳酸盐签名有关，以评估甲烷释放的营养途径和古代释放。古细菌和AOM被认为是两者的关键。脱殖的碳酸盐底物将部署在活性和无效部位，以检查早期的动物延长和外部渗漏的作用。具有适当的操纵控制的非活动部位和活性位点之间移植的岩石将提供有关在没有渗漏的情况下对AOM渗透和持续性的动物依赖的其他信息。社区比较将与渗水沉积物，其他生物底物（贻贝，蛤，tubeworms）以及其他深海还原和硬地面系统（通风孔，鲸鱼，深水珊瑚）一起绘制。 Macrofaunal assemblages will be DNA and selected annelid and foraminiferan taxa will be targeted for phylogenetic analyses to assess evolutionary affinities with fauna from other hardground-reducing ecosystems (vents).Broader Impacts: Benefits of this research to society include: (1) an understanding of seep carbonate ecosystems for improved marine resource management and more comprehensive assessments of seafloor生物多样性，碳循环以及对极端环境的适应； （2）一种模型，用于碳酸盐生态系统的继承变化以及使用动物区系作为代理，以更准确地评估过去的甲烷释放和古气候变化。教育和外展活动将包括当地的学校演讲；网站开发和跨学科，动手，对本科，研究生和大多数阶级的未来科学家的接近培训，包括通过冲浪，明星和REU计划招募的代表性不足的群体（妇女；来自农村社区的第一代大学生）。研究结果将纳入讲座，练习和实地考察，以进行深海生物学，微生物学，地质学，古生物学，海洋学和底栖生态学课程，以及由海洋生物和Sio Benthic无脊椎动物的人口普查管理的网站和数据库。