ANT LIA: Collaborative Research: Mixotrophic Grazing as a Strategy to meet Nutritional Requirements in the Iron and Manganese Deficient Southern Ocean

混合营养体是南极浮游生物群落的重要组成部分，它们既能进行光合作用，也能吸收细菌等小颗粒来满足自己的营养需求。该项目旨在了解混合营养体在南大洋微量营养素限制下的生理反应，特别是铁、锰和同时限制一种以上的微量金属，或共仿。这样的环境条件是南大洋的特点，只能用当地的藻类进行测试。主要研究人员假设，在微量金属共拟下，一些混合营养体将通过增加它们消耗粒子的能力来获得能量和从猎物身上获得微量金属，从而具有竞争优势。鉴于缺乏对混合营养体如何适应微量营养素限制的了解，研究人员建议用从南大洋分离的微藻培养物进行研究；他们将测量生长反应、消耗行为、细胞化学变化和遗传物质转录对铁和锰限制的反应。这个项目有利于国家科学基金会的目标，即了解南极洲的生命和有机体对这种极端环境的适应。社会将从拟议的培训中受益，农村大学的学生将学习计算机编码和科学数据分析。此外，这项工作将支持一名研究生，两名本科生暑期实习生和两名早期职业科学家。主要研究人员假设，在铁锰共生的情况下，一些混合营养体将通过提高它们的放牧率来从猎物那里获得能量、铁和锰，从而获得竞争优势。由于缺乏对混合营养物如何适应这些微量营养素可用性的季节性变化以及它们如何影响混合营养物生长动力学的了解，PIs建议进行培养研究，以测量生长响应、放牧行为以及铁和锰限制下元素化学计量学的变化。转录组学分析将揭示营养行为和微量营养素胁迫反应的代谢基础，并对碳固定、再矿化和养分循环等关键生物地球化学过程产生影响。研究结果有望阐明南极混合营养体的生态作用，并阐明南大洋生物对其独特的极地生态系统的适应性。这项工作将支持一名研究生，两名本科生暑期实习生和两名早期职业科学家。将组织一系列虚拟编码和生物信息学讲习班，在这些讲习班中，将向本科生讲授编码的基本原理和拟议分析中使用的数据处理。农村地区的小型学院将有8个模块的生物信息学培训。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Mixotrophs are essential components of the Antarctic planktonic community able to photosynthesize and also ingest small particles like bacteria to meet their nutritional needs. This project aims to understand the physiological response of mixotrophs exposed to micronutrient limitation in the Southern Ocean, specifically iron, manganese and simultaneous limitation of more than one trace metal, or colimitation. Such environmental conditions are characteristic of the Southern Ocean and can only be tested with local algae. The Principal Investigators hypothesize that under trace metal colimitation, some mixotrophs will have a competitive advantage by increasing their ability to consume particles to obtain energy and trace metals from their prey. Given the lack of understanding of how mixotrophs have adapted to the micronutrient limitation, the researchers propose studies with microalgal cultures isolated from the Southern Ocean; they will measure growth responses, consumption behavior, changes in cellular chemistry and transcription of genetic material in response to iron and manganese limitation. This project benefits the National Science Foundation goals of understanding Life in Antarctica and adaptation of organisms to this extreme environment. Society will benefit from the training proposed, whereby students from rural colleges will be instructed in computer coding and scientific data analyses. Furthermore, this work will support one graduate student, two undergraduate summer interns, and two early career scientists.The Principal Investigators hypothesize that under Fe-Mn colimitation, some mixotrophs will have a competitive advantage by increasing their grazing rates to obtain energy, Fe, and Mn from their prey. Given the lack of understanding of how mixotrophs have adapted to seasonal changes in the availability of these micronutrients and how they influence mixotrophic growth dynamics, the PIs propose culture studies to measure growth responses, grazing behavior, and changes in elemental stoichiometry in response to Fe and Mn limitation. Transcriptomic analyses will reveal the metabolic underpinnings of trophic behavior and micronutrient stress responses, with implications for key biogeochemical processes such as carbon fixation, remineralization, and nutrient cycling. Results are expected to clarify the ecological roles of Antarctic mixotrophs and elucidate the adaptations of Southern Ocean organisms to their unique polar ecosystem following the 2015 Strategic Vision for Polar Programs. This work will support one graduate student, two undergraduate summer interns, and two early career scientists. A series of virtual coding and bioinformatic workshops will be organized, in which basic principles of coding, and data processing used in the proposed analysis will be taught to undergraduate students. Small colleges in rural areas will be targeted for 8 modules on bioinformatics training.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.