GEOTRACES Pacific Section: Characterizing biogenic trace elements across productivity and oxygen gradients in the eastern South Pacific

微量元素进入浮游生物，以及影响这一过程的化学、地质、生物和生化机制，对我们了解海洋的生物地球化学功能至关重要。Fe、Zn、Co、Cu和Ni等生物活性te具有控制海洋生产力、生态系统结构和全球海洋大范围内大量营养物质利用的潜力。已经进行了大量的实验室研究，以研究模型菌株的细胞TE配额对不同环境条件的响应，但是从自然群落中收集的细胞和生物源材料中TE化学计量的精确测量很少。体积颗粒TE化学计量学的测量通常依赖于与实验室结果的比较来评估生物成分，从而排除了对地球化学梯度的细胞反应的研究。在这个项目中，Bigelow海洋科学实验室和缅因大学的研究人员将于2013年沿着美国GEOTRACES南太平洋带样带从秘鲁到塔希提岛测量浮游生物细胞中代表主要功能群的TEs和大块颗粒物质。ususgeotraces是国际GEOTRACES计划的美国组成部分，该计划旨在提高我们对海洋中te的浓度、物理和化学形态以及空间分布的了解。太平洋横断面将从一个高产的东部边界上升流系统与一个高氧最低区，东南太平洋环流，世界上最少营养的制度之一。具体而言，研究人员希望实现以下目标：(1)测量南太平洋热带东部浮游植物主要功能群在水平生产力梯度上的P、Si、Mn、Fe、Co、Ni、Cu和Zn的细胞配额；(2)通过南太平洋东部热带海洋表层垂直氧化还原梯度测量浮游植物和细菌中P、Si、Mn、Fe、Co、Ni、Cu和Zn的细胞配额；(3)用GO-Flo瓶测量从上层500米收集的大块颗粒材料中Al、Ti、P、Mn、Fe、Co、Ni、Cu、Zn、Cd、V和Mo的总浓度和不稳定浓度。更广泛的影响：本研究的更广泛影响和环境相关性将通过与COSEE-Ocean Systems协调组织的专门网络研讨会系列向教育工作者和公众传达。该系列将包括5个网络研讨会，依次举行，涵盖该项目产生的科学成果，以及来自南太平洋巡航的其他四个GEOTRACES项目的结果和综合。这些研讨会将介绍国际GEOTRACES计划的更广泛目标和意义，向教育工作者和公民推广这一全球地球化学计划，并综合项目各方面的发现（溶解的、微粒的和生物源的微量金属；金属结合配体；天然放射性核素示踪剂）。来自GEOTRACES的信息也将通过毕格罗大学的REU项目和附近科尔比学院的本科课程介绍给本科生。

Incorporation of trace elements (TE) into plankton, and the chemical, geological, biological and biochemical mechanisms which influence this process, are of central importance to our understanding of the biogeochemical functioning of the oceans. Bioactive TEs such as Fe, Zn, Co, Cu and Ni have the potential to control ocean productivity, ecosystem structure, and the utilization of macronutrients in large regions of the global ocean. Numerous laboratory studies have been performed to study the responses of cellular TE quotas in model strains to varying environmental conditions, but accurate measurements of TE stoichiometries in cells and biogenic material collected from natural communities are rare. Measurements of bulk particulate TE stoichiometries typically rely on comparison to laboratory results to assess the biogenic component, precluding study of cellular responses to geochemical gradients.In this project, investigators at the Bigelow Laboratory for Ocean Sciences and the University of Maine will measure TEs in plankton cells representing major functional groups and in bulk particulate matter along the US GEOTRACES South Pacific Zonal Transect from Peru to Tahiti in 2013. U.S.GEOTRACES is the US component of the international GEOTRACES program which was initiated to advance our knowledge of the concentrations, physical and chemical speciation, and spatial distributions of TEs in the ocean. The Pacific transect will run from a highly productive eastern boundary upwelling system with an intense oxygen minimum zone to the southeast Pacific gyre, one of the world's most oligotrophic regimes. Specifically, the investigators expect to accomplish the following objectives: (1) Measure cellular quotas of P, Si, Mn, Fe, Co, Ni, Cu and Zn in major functional groups of phytoplankton across horizontal productivity gradients in the eastern tropical South Pacific Ocean; (2) Measure cellular quotas of P, Si, Mn, Fe, Co, Ni, Cu and Zn in phytoplankton and bacteria across vertical redox gradients in the OMZ of the eastern tropical South Pacific Ocean; ( 3) Measure total and labile concentrations of Al, Ti, P, Mn, Fe, Co, Ni, Cu, Zn, Cd, V and Mo in bulk particulate material collected from the upper 500 m with GO-Flo bottles. Broader Impacts: The broader impacts and environmental relevance of this research will be communicated to educators and the general public through a dedicated webinar series to be organized in coordination with COSEE-Ocean Systems. This series will involve 5 webinars delivered sequentially and covering the science results produced by this project, as well as results and synthesis from four other GEOTRACES projects from the South Pacific cruise. These seminars will describe the broader goals and significance of the international GEOTRACES program, promoting this global geochemical program to educators and citizens, as well as synthesizing findings on various aspects of the project (dissolved, particulate, and biogenic trace metals; metal binding ligands; natural radionuclide tracers). Information from GEOTRACES will also be introduced to undergraduate students through Bigelow's REU program and through an undergraduate course being taught to students at nearby Colby College.