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

混合养殖体是南极浮游生物群落的重要组成部分，能够进行光合作用，也能摄取细菌等小颗粒以满足其营养需求。该项目旨在了解在南大洋暴露于微量营养素限制，特别是铁、锰和同时限制一种以上痕量金属或共生的混合营养生物的生理反应。这种环境条件是南大洋特有的，只能用当地的藻类进行测试。首席调查人员假设，在微量金属共生的情况下，一些混合营养体将具有竞争优势，因为它们增加了从猎物中消耗粒子以获取能量和痕量金属的能力。鉴于缺乏对混合营养生物如何适应微量营养素限制的了解，研究人员建议使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、消费行为、细胞化学变化以及遗传物质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生物对这种极端环境的适应。社会将从拟议的培训中受益，农村大学的学生将接受计算机编码和科学数据分析方面的指导。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。首席调查人员假设，在铁-锰共存的情况下，一些混合营养物将具有竞争优势，通过提高它们的捕食率来从猎物中获取能量、铁和锰。鉴于缺乏对混合营养生物如何适应这些微量营养素可获得性的季节性变化以及它们如何影响混合营养生长动态的了解，PIs建议进行培养研究，以衡量对铁和锰限制的生长反应、放牧行为和元素化学计量比的变化。转录组分析将揭示营养行为和微量营养素应激反应的代谢基础，并涉及关键的生物地球化学过程，如碳固定、再矿化和营养循环。预计结果将澄清南极混合养殖体的生态作用，并阐明南大洋生物根据2015年极地战略愿景方案对其独特的极地生态系统的适应。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，向本科生讲授拟议分析中使用的编码和数据处理的基本原理。农村地区的小型学院将针对生物信息学培训的8个模块。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.