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

混合营养生物是南极浮游生物群落的重要组成部分，能够进行光合作用并摄取细菌等小颗粒以满足其营养需求。该项目旨在了解南大洋中混合营养生物受到微量营养素限制（特别是铁、锰以及同时限制多种微量金属或共限制）的生理反应。这种环境条件是南大洋的特征，只能用当地藻类进行测试。首席研究员假设，在微量金属共限制下，一些混合营养生物将通过提高消耗颗粒以从猎物中获取能量和微量金属的能力来获得竞争优势。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，研究人员建议对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转录对铁和锰限制的反应。该项目有利于美国国家科学基金会了解南极洲生命和生物体适应这种极端环境的目标。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，这项工作还将支持一名研究生、两名本科生暑期实习生和两名早期职业科学家。 首席研究员假设，在铁锰共限制下，一些混合营养动物将通过提高放牧率从猎物中获取能量、铁和锰来获得竞争优势。鉴于缺乏对混合营养生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生长动态的了解，PI建议进行培养研究来测量生长反应、放牧行为以及元素化学计量因铁和锰限制而发生的变化。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，并对碳固定、再矿化和营养循环等关键生物地球化学过程产生影响。预计结果将阐明南极混合营养生物的生态作用，并根据 2015 年极地计划战略愿景阐明南大洋生物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研讨会，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。农村地区的小型大学将针对生物信息学培训的 8 个模块。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，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.