Copper and iron limitation and interaction in marine diatoms

在公海表层水域中，溶解金属的浓度在任何环境中都是最低的。大多数金属是浮游生物所必需的，它们是参与细胞新陈代谢的酶和氧化还原蛋白的辅助因子。它们催化的反应和化学转化是地球上所有主要生物地球化学循环的关键部分。铁是海水中最难溶的金属之一，是当代海洋浮游植物的有限资源。其低浓度限制了碳(C)的产生，影响了群落的结构和功能，并影响了其他金属和常量营养素的循环。发现影响铁的有效性和利用率的过程是理解铁有限海洋生态的关键。这些知识将告诉我们海洋是如何发挥生物功能的，以及它可能如何应对未来的变化。这项研究的目标是：1)研究自养和异养浮游生物如何获取痕量金属，以及在它们受到限制时如何适应和适应；2)确定这些金属在细胞新陈代谢中所起的主要作用；3)确定海洋中金属限制的症状和后果(生态和生物地球化学)。这项建议涉及三个与目标有关的重要问题：1)海洋硅藻中铜替代铁的普遍程度？2)铜限制在海洋中有多普遍，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理解铁如何调节海洋中的浮游生物生产，以及生物如何适应和竞争这种有限的资源。

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.