Copper and iron limitation and interaction in marine diatoms

公海的表层沃茨中溶解金属的浓度是所有环境中最低的。 大多数金属是浮游生物所必需的，作为参与细胞代谢的酶和氧化还原蛋白质的辅助因子。 它们催化的反应和化学转化是地球上所有主要地球化学循环的关键部分。 铁（Fe）是海水中溶解度最低的金属之一，是现代海洋浮游植物的限制性资源。 其低浓度限制了碳（C）的产生，影响群落结构和功能，并影响其他金属和常量营养素的循环。 发现影响铁的可用性和利用的过程是了解铁有限的海洋生态的关键。这些知识将使我们了解海洋在生物学上的功能，以及它如何应对未来的变化。研究的目的是：1）研究自养和异养浮游生物如何获取微量金属，并适应和驯化时，他们是有限的，2）确定这些金属在细胞代谢中发挥的主导作用，3）确定症状和后果（生态和海洋地球化学）的金属限制在海洋中。 该提案涉及与目标相关的三个重要主题：1）在海洋硅藻中Cu取代Fe的情况有多普遍？2)铜限制在海洋中的普遍程度如何？它如何影响浮游植物对铜和铁的吸收？3）铁限制如何影响浮游植物对其他金属的需求及其耐受氧化胁迫的能力？ 这项工作将有助于我们了解铁如何调节海洋浮游生物的生产，以及生物体适应和竞争这种有限资源的方式。

Surface waters of the open sea contain some of the lowest concentrations of dissolved metals of any environment. Most of the metals are essential for plankton, as co-factors of enzymes and redox proteins involved in cellular metabolism. They catalyze reactions and chemical transformations that are critical parts of all of the major biogeochemical cycles on Earth. Iron (Fe), one of the least soluble metals in seawater, is a limiting resource for phytoplankton in the contemporary ocean. Its low concentration restricts carbon (C) production, influences community structure and function, and affects the cycling of other metals and macronutrients. Discovering the processes that influence Fe availability and utilization are key to understanding the ecology of the Fe-limited sea. This knowledge will inform us of how the ocean functions biologically and how it may respond to change in the future. The objectives of the research are: 1) to study how autotrophic and heterotrophic plankton acquire trace metals and adapt and acclimate when they are limiting, 2) to determine the dominant roles that these metals play in cellular metabolism, and 3) to identify the symptoms and consequences (ecological and biogeochemical) of metal limitation in the sea. This proposal addresses three important topics that relate to the objectives: 1) How widespread is Cu substitution for Fe in oceanic diatoms?, 2) How prevalent is Cu limitation in the sea and how does it affect Cu and Fe uptake by phytoplankton?, and 3) How does Fe-limitation affect the requirements of phytoplankton for other metals and their abilities to tolerate oxidative stress? The work will contribute to our understanding of how Fe regulates plankton production in the sea and the ways in which organisms adapt and compete for this limiting resource.