RII Track-4: Peering into Nature's Glass Boxes - using nano-Raman Spectroscopy to answer Novel Questions in Diatom-focused Environmental Research

硅藻是丰富的微观海洋“植物”，有一个由玻璃制成的保护壳。尽管硅藻体积很小，但它们在海洋生态系统中的集体重要性是巨大的。它们产生的氧气相当于全球所有雨林的总和。它们的玻璃外壳（即硅藻土）也有许多工业用途。与生长相对缓慢的陆地植物不同，硅藻生物量积累快，并在海水中迅速回收。硅藻生物质的回收利用每年向海洋释放5-10亿吨碳，这一碳量超过了全球化石燃料的排放量。该项目将使用最先进的技术来检查玻璃外壳的特性，并确定它们如何影响硅藻-生物质回收。这项技术使用单细胞分析，而不是传统的需要数千个细胞的方法，从而使人们对单细胞材料的组成和结构有了新的认识和见解。这个项目将有助于将这项技术应用到硅藻研究中，并为博士生提供培训。该项目与石溪大学的科学家合作，将帮助阿拉巴马州海豚岛海洋实验室的研究人员成为各自领域的领导者。此外，考虑到硅藻土的广泛工业应用，这些方法可能对工业有用。这些专业知识将使未来的工作能够满足墨西哥湾北部（阿拉巴马州、密西西比州、路易斯安那州）独特的环境研究需求。硅藻是水生浮游植物，其特点是其硅壳，占海洋初级产量的20-40%。死后的二氧化硅溶解在生产后的几天或几周内释放硅藻有机物，这相当于每年5-10毫克的碳被回收到海洋中，这一碳量超过了全球化石燃料的排放量。由于硅藻有机物的长期命运部分取决于它们的外壳是否溶解，因此该项目旨在了解硅藻二氧化硅中的有机物如何影响其溶解。该项目将摆脱对当前方法（需要数千个细胞）的依赖，并在单个细胞水平上检查过程。拉曼光谱可以提供材料组成和结构的详细单细胞信息。样本分析将在石溪大学的NARMIL设施进行。该设施拥有最先进的仪器设备，用于测试与理解硅藻生长条件如何影响二氧化硅包裹的有机物质以及沉积保存的硅藻是否具有共同的有机物质特征有关的假设。这个项目的影响将超出其工期。PI的小组将建立一个方法学工具集，尚未在他的子领域得到充分利用，考虑到硅藻硅（硅藻土）的广泛工业应用，这些方法可能对工业有用。博士生将接受这些方法和分析方面的培训。这种合作还将促进数据集的开发和出版，这将使位于阿拉巴马州的PI通过应用这些方法来解决墨西哥湾北部及其他地区的新问题，从而在未来的提案中具有竞争力。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。

Nontechnical DescriptionDiatoms are abundant microscopic oceanic 'plants' which have a protective shell made of glass. Despite their small size, diatoms' collective importance in marine ecosystems is immense. They produce as much oxygen globally as all the rain forests combined. Their glass shell (i.e. diatomaceous earth) also has many industrial applications. Unlike land plants which grow relatively slow, diatom biomass accumulates fast and is rapidly recycled in seawater. The recycling of diatom biomass releases 5-10 billion metric tons of carbon back into the ocean annually -a quantity of carbon which exceeds global fossil-fuel emissions. This project will use state-of-the-art technology to examine the properties of the glass shell and determine how they affect diatom-biomass recycling. This technology uses single-cell analysis, instead of traditional methods which require thousands of cells, thereby enabling new understanding and insight of single-cell material composition and structure. This project will help entrench this technology into diatom-based research and provide training for a Ph.D. student. The project collaboration with Stony Brook University based scientist will help researchers at the Alabama-based Dauphin Island Sea Lab personnel to emerge as leaders in their subfields. Also considering the vast industrial application for diatomaceous earth, these approaches may be useful for industry. This expertise will enable future work to serve the unique environmental research needs in the northern Gulf of Mexico (Alabama, Mississippi, Louisiana).Technical DescriptionDiatoms are aquatic phytoplankton, characterized by their silica shell, which account for 20-40% of marine primary production. Post-mortem silica dissolution liberates diatom organic matter within days or weeks after production, this equates to 5-10 Pg of carbon being recycled back into the ocean annually -a quantity of carbon which exceeds global fossil-fuel emissions. Because the long-term fate of diatom organic matter is governed in part by whether their shell dissolves, this project aims to understand how organic matter within diatom silica affects its dissolution. This project will move away from reliance on current methods (which require thousands of cells) and examine processes at the single-cell level. Raman spectroscopy can provide detailed single-cell information on material composition and structure. Sample analyses will be done at the NARMIL facility at Stony Brook University. This facility houses the state-of-the-art instrumentation necessary to test hypotheses related to understanding how silica-encased organic matter is affected by diatom growth conditions and whether sediment-preserved diatoms share common organic-matter traits. This project will have broader impact beyond its duration. The PI's group will build a methodological tool set that has yet to be fully utilized in his subfield and considering the vast industrial application of diatom silica (diatomaceous earth) these approaches may be useful for industry. A Ph.D. student will be trained in these methods and analyses. This collaboration will also foster data set development and publications which will enable the Alabama-based PI to be competitive for future proposals by applying these approaches to address novel questions in the northern Gulf of Mexico and beyond.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.