Trace element cycling in upwelling filaments in the California Current System

锰、铁、镍、钴、铜和锌等微量元素在海洋生物过程中起着重要作用。 在浮游植物生长并支撑着海洋食物网基础的表层沃茨中，微量元素的浓度往往微乎其微。这对海洋生物提出了巨大的挑战，微量元素可能是浮游植物生产力的限制因素。 海洋系统中的生物过程，如浮游植物生长、放牧、溶解有机物生产和沉积，反过来又会对微量元素在海洋中的循环产生重要影响。这些相互关系是复杂的，并没有得到很好的理解，但它们对生态系统的生产力和全球养分循环有重要的影响。本研究旨在研究加州沿岸海流系统中微量元素分布与化学和生物过程之间的关系。 实地研究将利用正在进行的加州当前生态系统长期生态研究（CCE-LTER）网站，该网站已经为2019年和2021年的游轮计划提供了资金。这一项目将支持研究生的教育和培训，并支持主要研究生和研究生参与通过CCE-LTER项目开展的教育和外联活动，包括在研究项目中指导本科生，并通过斯克里普斯的桦树水族馆为公众教育和宣传做出贡献。微量元素微量营养素的可用性越来越被认为是对人类健康的重要影响。海洋浮游植物群落的生产力和结构。微量元素本身在海洋系统中的停留时间、化学形态和循环方面受到生物过程的强烈影响。 现场过程的研究，充分表征的生物和物理动力学的上层海洋系统，同时测定多种微量元素原位有可能大大告知我们的理解微量元素和生物群之间的耦合相互作用，但这样的研究是比较罕见的，由于其跨学科的复杂性和费用。该提案寻求支持，以利用正在进行的加州当前生态系统长期生态研究计划（CCE-LTER）进行这样的研究。2019年和2021年即将进行的两次LTER过程巡航将通过调查绘图，详细采样和拉格朗日过程测量相结合，描述上升流细丝在离岸移动时的地球化学和生态演变。该项目为购置和建立seaFAST皮科预浓缩系统和ICP-MS分析时间提供资金，这将使研究这些航行中的多种微量元素成为可能。这种类型的中尺度特征很少从微量元素地球化学的角度来描述，我们预计，我们的研究结果将是海洋学界的广泛兴趣。一些假设的源，汇和循环的微量元素在上升流丝将在拟议的工作进行审查。该项目还将利用CCE-LTER内正在进行的研究合作，将多元素微量元素数据集与关于群落结构和功能以及溶解有机物组成的分子一级信息结合起来。这将有助于探索生物群落对多因素共同限制的反应，有机分子在介导痕量金属循环中的作用，以及痕量金属循环与碳，氮和二氧化硅循环的耦合。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

Trace element micronutrients such as manganese, iron, nickel, cobalt, copper and zinc play important roles in biological processes in the ocean. In surface waters where phytoplankton grow and support the base of the marine food web, trace elements are often present at vanishingly small concentrations. This presents great challenges to marine life, and trace elements can be limiting factors for phytoplankton productivity. Biological processes in marine systems like phytoplankton growth, grazing, dissolved organic matter production, and sedimentation can in turn have important impacts on how trace elements cycle through the ocean. These inter-relationships are complex and not very well understood, but they have important ramifications for ecosystem productivity and global nutrient cycling. The research proposed here seeks to study the relationships between trace element distributions and chemistry and biological processes in a dynamic and ecologically significant environment - upwelling filaments in the coastal California Current System. Field studies will take advantage of the ongoing California Current Ecosystem Long Term Ecological Research (CCE-LTER) site, which already has funded cruises planned for 2019 and 2021. This project will support the education and training of graduate students, and the participation of both the PI and graduate students in education and outreach activities carried out through the CCE-LTER project, including mentoring undergraduates in research projects and contributing to public education and outreach through the Birch Aquarium at Scripps.The availability of trace element micronutrients is increasingly recognized as an important influence on the productivity and structure of marine phytoplankton communities. Trace elements themselves are strongly influenced by biological processes in terms of their residence time, chemical speciation, and cycling in marine systems. Field process studies which fully characterize the biological and physical dynamics of upper ocean systems with simultaneous determination of multiple trace elements in situ have the potential to greatly inform our understanding of the coupled interactions between trace elements and biota, but such studies are comparatively rare due to their interdisciplinary complexity and expense. This proposal seeks support to perform such a study by leveraging the ongoing California Current Ecosystem Long Term Ecological Research program (CCE-LTER). Two upcoming funded LTER process cruises in 2019 and 2021 will characterize the biogeochemical and ecological evolution of upwelling filaments as they move offshore via a combination of survey mapping, detailed sampling and Lagrangian process measurements. This project funds the acquisition and setup of a seaFAST pico preconcentration system and ICP-MS analytical time which will enable the study of multiple trace elements in the context of these cruises. This type of mesoscale feature has rarely been characterized from the standpoint of trace element biogeochemistry, and we anticipate that our findings will be of broad interest to the oceanographic community. A number of hypotheses regarding the sources, sinks and cycling of trace elements in an upwelling filament will be examined in the proposed work. This project will also take advantage of ongoing research collaborations within CCE-LTER to couple multi-elemental trace element data sets with molecular-level information on community structure and function and dissolved organic matter composition. This will facilitate exploration of the response of biological communities to multi-factorial co-limitation, the role of organic molecules in mediating trace metal cycles, and the coupling of trace metal cycles with the cycles of carbon, nitrogen, and silica.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.