ANT LIA: Collaborative Research: Adaptations of Southern Ocean Diatoms to Manganese Scarcity: Can Physiological Ingenuity Overcome Unfavorable Chemistry?

ANT LIA：合作研究：南大洋硅藻对锰稀缺的适应：生理学的独创性能否克服不利的化学因素？

• 批准号: 2149071
• 负责人: Natalie Cohen
• 金额: $ 22.49万
• 依托单位: University of Georgia Research Foundation Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-02-01 至 2026-01-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2149071&HistoricalAwards=false
• 关键词: ANT; LIA; Collaborative; Research; Adaptations

The current understanding of what controls productivity in the Southern Ocean is based mostly on the scarcity of a metal compound needed for algal growth, Dissolved Iron in seawater. There is growing evidence that Manganese also plays a critical role in maintaining algal growth and if found in low concentrations can play a role in limiting primary productivity. As algal growth is a major player in absorbing carbon dioxide from the atmosphere, understanding what controls productivity increases our understanding of what role the Southern Ocean plays in the global carbon cycle. This study proposes to study the algal processes that take up Manganese in Antarctic diatoms, one of the main primary producers in the region. Another aspect will be to understand how Zinc, a micronutrient with similar dynamics than Manganese, can inhibit its uptake. The PIs propose lab experiments with cultured diatoms isolated from the Southern Ocean to obtain answers to their questions on micronutrient dynamics and will compare results from those obtained with a diatom species isolated from temperate waters. The proposed research will benefit NSF’s goals of understanding life in cold environments and how they differ from other parts of the ocean. This project will support two first-time early career scientists and a female researcher in Earth Sciences. Two graduate students will also be supported, and scientific techniques used in this research will be shared at open houses sponsored by the academic institutions and with local summer schools. This proposal represents collaborative research to explore manganese (Mn) limitation in Antarctic diatoms by two early career investigators. Diatoms are central players in the Southern Ocean carbon cycle, where the micronutrient chemistry is fundamentally different from other oceans. The Southern Ocean is characterized by widespread low Mn, coupled with high zinc (Zn). High Zn levels are potentially toxic to diatoms as Zn can competitively inhibit Mn uptake and metabolism, compromising the ability of building critical cellular components, thus impacting the biological pump. Using culture experiments with a matrix of micronutrient treatments (Mn, Zn, Fe) and irradiances, and using physiological and transcriptomic approaches, along with biochemical principles, the Principal Investigators will address the central hypothesis (diatoms from the Southern Ocean possess physiological mechanisms to low Mn/high Zn) to quantify rates of uptake and transporter binding constants. The transcriptomics approach will help to identify candidate genes that may provide Antarctic diatoms physiological mechanisms in low Mn/high Zn environment. The project does not require fieldwork but instead would make use of culture experiments with 4 diatom species (3 Antarctic, and 1 temperate). The proposed approach will also enable the goal of developing biomarker(s) for assessing Mn stress or Zn toxicity and results from the physiological experiments will help parameterize models of micronutrient limitation in the Southern Ocean.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.

目前对控制南大洋生产力的因素的理解主要是基于藻类生长所需的金属化合物的缺乏，即海水中的溶解铁。越来越多的证据表明，锰在维持藻类生长方面也起着关键作用，如果浓度低，则会限制初级生产力。由于藻类生长是从大气中吸收二氧化碳的主要参与者，了解是什么控制了生产力，可以增加我们对南大洋在全球碳循环中扮演的角色的了解。本研究旨在研究该地区主要初级生产者之一的南极硅藻吸收锰的藻类过程。另一个方面将是了解锌，一种与锰具有相似动力学的微量营养素，如何抑制其吸收。研究所建议用从南大洋分离的培养硅藻进行实验室实验，以回答他们关于微量营养素动态的问题，并将结果与从温带沃茨分离的硅藻物种进行比较。这项拟议中的研究将有助于NSF了解寒冷环境中的生命以及它们与海洋其他部分的差异。该项目将支持两名首次从事早期职业的科学家和一名地球科学领域的女性研究人员。还将资助两名研究生，并在学术机构和当地暑期学校赞助的开放日上分享本研究中使用的科学技术。 该提案代表了两名早期职业调查人员的合作研究，以探索南极硅藻中的锰（Mn）限制。硅藻是南大洋碳循环的核心参与者，那里的微量营养素化学与其他海洋根本不同。南大洋的特点是广泛的低锰，加上高锌（Zn）。高锌水平对硅藻具有潜在毒性，因为锌可以竞争性地抑制锰的吸收和代谢，损害构建关键细胞组分的能力，从而影响生物泵。利用培养实验与矩阵的微量营养素治疗（锰，锌，铁）和辐照度，并使用生理和转录组学的方法，沿着与生物化学原理，主要研究人员将解决中心的假设（硅藻从南大洋具有生理机制，以低锰/高锌），以量化的吸收率和转运蛋白结合常数。 转录组学的方法将有助于确定候选基因，可能提供南极硅藻在低锰/高锌环境中的生理机制。该项目不需要实地考察，而是利用4种硅藻（3种南极硅藻和1种温带硅藻）进行培养实验。拟议的方法也将使开发生物标志物（S）的目标，用于评估锰应力或锌毒性和生理实验的结果将有助于在南大洋微量营养素限制的参数化模型。该奖项反映了NSF的法定使命，并已被认为是值得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的支持。