Assessing the chemical speciation and bioavailability of iron regenerated by marine zooplankton

铁（Fe）是上层海洋必需的，但通常是限制性的营养素。铁的来源包括外部输入，以及原位再生，由于铁在地表沃茨通过生物吸收和再生，包括通过浮游动物放牧的快速循环。浮游植物生物量在浮游动物肠道消化，预计会导致化学氧化还原和形态的变化，这将影响铁的生物利用度，但这个循环过程仍然研究不足。目前的项目将通过一系列实验室和实地调查来研究这一主题，这些调查将探讨放牧对化学形态和生物利用度的影响。这些研究将调查不同浮游动物消化泡/肠道的pH值和氧化还原状态，并研究如何捕食？食草动物的动态影响再生铁的形态，其生物利用度的模式浮游植物的文化。实地实验还将检查铁再生，物种形成和生物利用率使用自然猎物-食草动物组合从沿海和公海沃茨在巡航期间通过其他计划资助。该项目将通过毕格罗海洋实验室的项目，在缅因州的机构教育和培训高中、本科和博士后学生和科学家。 本科生将通过毕格罗REU计划参与学习。总的来说，该项目将通过侧重于这一重要研究领域的一个方面，提供关于海洋微生物吸收铁的来源和途径以及影响海洋沃茨生物利用率的因素的重要信息。

Iron (Fe) is a required, but often limiting nutrient, in the upper ocean. Sources of Fe include external inputs, as well an in situ regeneration due to the rapid recycling of Fe in surface waters through biological uptake and regeneration, including via zooplankton grazing. Digestion of phytoplankton biomass in zooplankton guts is expected to result in chemical redox and speciation changes which will affect Fe bioavailability, but this recycling process remains understudied. The current project will examine this topic through a series of laboratory and field investigations which will probe the consequences of grazing on chemical speciation and bioavailability. The studies will investigate the pH and redox state in the digestive vacuole/guts of different zooplankton, and examine how prey ? grazer dynamics influences the speciation of regenerated Fe, and its bioavailability to cultures of model phytoplankton. Field experiments will also examine Fe regeneration, speciation and bioavailability using natural prey - grazer assemblages from coastal and open ocean waters during cruises funded through other programs. The project will educate and train students and scientists at the high school, undergraduate and post-doctoral levels at institutions in Maine, and through programs at the Bigelow Marine Lab. Undergraduates will be involved in studies through the Bigelow REU program. Overall, the project will provide important information on the sources and pathways of iron uptake into marine microbes and the factors influencing bioavailability in marine waters by focusing on one aspect of this important research area.