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: 2149070
• 负责人: Nicholas Hawco
• 金额: $ 26.25万
• 依托单位: University of Hawaii
• 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=2149070&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基于藻类生长所需的金属化合物的稀缺，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发挥着关键作用，如果在海水中发现锰的话。低浓度可能会限制初级生产力。由于藻类生长是吸收大气中二氧化碳的主要因素，了解控制生产力的因素可以增加我们对南大洋在全球碳循环中所扮演的角色的了解。研究藻类过程南极硅藻是该地区的主要初级生产者之一，其吸收锰的另一个方面是了解锌（一种与锰具有相似动态的微量营养素）如何抑制其吸收，研究人员建议对从南极硅藻中分离出来的培养硅藻进行实验室实验。南大洋将获得有关微量营养素动态问题的答案，并将与从温带水域分离出的硅藻物种获得的结果进行比较。拟议的研究将有利于国家科学基金会了解寒冷环境中的生命以及如何实现这一目标。它们与海洋的其他部分不同，该项目将支持两名首次从事地球科学的早期职业科学家和一名女研究员，并将在赞助的开放日中分享这项研究中使用的科学技术。该提案代表了两位早期职业研究人员对南极硅藻中锰 (Mn) 限制的合作研究。硅藻是南大洋碳循环的核心参与者，其微量营养素化学性质与南大洋碳循环有着根本的不同。其他海洋。南大洋的特点是锰含量普遍较低，而锌 (Zn) 含量较高，对硅藻具有潜在毒性，因为锌会竞争性抑制锰的吸收和代谢，损害构建关键细胞成分的能力，从而影响生物泵。通过使用微量营养素处理（Mn、Zn、Fe）和辐照矩阵的培养实验，并使用生理学和转录组学方法以及生化原理，主要研究人员将解决中心假设（硅藻来自南大洋具有低锰/高锌的生理机制，以量化摄取率和转运蛋白结合常数，转录组学方法将有助于识别可能提供低锰/高锌环境中南极硅藻生理机制的候选基因。需要实地工作，但会利用 4 种硅藻（3 种南极硅藻和 1 种温带硅藻）进行培养实验。所提出的方法还将实现开发用于评估锰胁迫或的生物标记物的目标。锌的毒性和生理实验的结果将有助于参数化南大洋微量营养素限制模型。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，被认为值得支持。