Collaborative Research: US GEOTRACES GP-17-OCE: Molecular speciation of trace element-ligand complexes in the South Pacific Ocean

海洋中所有的微生物都需要铁来生长和繁衍。 这些铁是由强风从陆地携带到大洋彼岸的尘埃或海洋深处的火山活动提供的。 然而，海洋的大部分区域远离陆地和深海火山活动，到达这些区域的铁量非常小。 在这些地区，微观生命往往受到铁浓度非常低的限制，这是该环境的特征。 为了利用铁，微生物必须首先从海水中提取铁。 为了做到这一点，一些微生物有能力制造独特的有机化合物，称为铁载体，专门用于从海水中捕获铁并将其运输到细胞中。 海水中铁载体的存在可以作为一个信号，了解海洋中铁可能限制微生物生产力的位置。美国GEOTRACES计划是一项多研究者合作的努力，旨在对主要海洋盆地的代表性部分的金属浓度进行高质量、高分辨率的测量。 GEOTRACES的数据将作为基准，在海洋对气候变化做出反应时，可以参考未来的测量结果。 海洋中大多数生物学上重要的金属都与铁载体等有机化合物结合在一起，我们项目的目标是在塔希提岛和南极洲之间的南太平洋和南大洋的一个部分上，在分子水平上识别和测量这些金属有机络合物。 该部分将由约30个均匀分布的地点组成，从海洋表面到底部收集海水样本。 将从这些样品中提取痕量金属有机络合物，并在实验室中分析含铁、铜、钴、镍、锌、锰和碘的络合物。 这些复合物的分子特性、浓度和水柱分布将被确定，并用于评估微生物如何获得和利用痕量金属和其他营养物质。 与此同时，还将收集和分析选定的样本的微生物基因组，以提供关于哪些类别的微生物制造和使用铁载体来获取铁的信息。 数据将存入国家和国际数据库。 该项目活动将有助于培养下一代海洋科学家，并告知公众科学如何为我们提供有关海洋的信息。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

All microscopic life in the ocean requires iron to grow and to thrive. This iron is supplied by dust that is carried from land out across the ocean by strong winds, or by volcanic activity deep within the ocean. However, large areas of the ocean are very remote from both land and deep-sea volcanic activity, and the amount of iron that reaches these areas is quite small. In these regions microscopic life is often limited by the very low concentrations of iron that characterize this environment. To use iron, microbes must first extract it from seawater. To do this, some microbes have the ability to manufacture unique organic compounds called siderophores that are specifically designed to capture iron from seawater and transport it into the cell. The presence of siderophores in seawater acts as a signal to know where in the ocean iron may be limiting microbial productivity.US GEOTRACES program is a cooperative, multi-investigator effort to make high quality, high-resolution measurements of metal concentrations across representative sections of major ocean basins. GEOTRACES data will serve as a benchmark against which future measurements, made as the ocean responds to climate change, can be referenced. Most biologically important metals in the ocean are bound to organic compounds such as siderophores, and the goals of our project are to identity and measure these metal-organic complexes at the molecular level on a section across the South Pacific and Southern Oceans between Tahiti and Antarctica. The section will consist of ~ 30 evenly spaced sites where samples of seawater will be collected from the surface to the bottom of the ocean. Trace-metal organic complexes will be extracted from these samples and analyzed in the laboratory for iron, copper, cobalt, nickel, zinc, manganese, and iodine containing complexes. The molecular identities, concentrations and water column distributions of these complexes will be determined, and used to assess how microbes acquire and use trace metals and other nutrients. In parallel, select samples will also be collected and analyzed for microbial genomes to provide information on which classes of microbes manufacture and use siderophores to acquire iron. Data will be archived in national and international databases. The project activities will help train the next generation of marine scientists and inform the public about how science can inform us about the ocean.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.