Collaborative Research: Defining the biogeochemical drivers of diatom physiological ecology in the North Atlantic

合作研究：定义北大西洋硅藻生理生态的生物地球化学驱动因素

• 批准号: 1558490
• 负责人: Tatiana Rynearson
• 金额: $ 82.77万
• 依托单位: University of Rhode Island
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1558490&HistoricalAwards=false
• 关键词: Collaborative; Research; Defining; biogeochemical; drivers

About half of photosynthesis on earth is generated by marine phytoplankton, single celled organisms that drift with tides and currents. Within the phytoplankton, the diatoms conduct nearly half of this photosynthesis, exerting profound control over global carbon cycling. Despite their importance, there are surprisingly fundamental gaps in understanding how diatoms function in their natural environment, in part because methods to assess in situ physiology are lacking. This project focuses on the application of a powerful new approach, called Quantitative Metabolic Fingerprinting (QMF), to address this knowledge gap and examine species-specific physiology in the field. The project will provide transformative insights into how ocean geochemistry controls the distribution of diatoms, the metabolic responses of individual diatom species, and how metabolic potential is partitioned between diatom species, thus providing new insights into the structure and function of marine systems. The overarching goal is to examine how diatom species respond to changes in biogeochemistry across marine provinces, from the coast to the open ocean, by following shifts in diatom physiology using QMF. This research is critical to understand future changes in oceanic phytoplankton in response to climate and environmental change. Furthermore, activities on this project will include supporting a graduate student and postdoctoral fellow and delivering the Artistic Oceanographer Program (AOP) to diverse middle school age children and teachers in the NYC metropolitan area and to middle-school girls in the Girl Scouts of RI, reaching an anticipated 60 children and 30 teachers annually. The programs will foster multidisciplinary hands-on learning and will directly impact STEM education at a critical point in the pipeline by targeting diverse middle-school aged groups in both NY and RI.In laboratory studies with cultured isolates, there are profound differences among diatom species' responses to nutrient limitation. Thus, it is likely that different species contribute differently to nutrient uptake, carbon flux and burial. However, marine ecosystem models often rely on physiological attributes drawn from just one species and apply those attributes globally (e.g. coastal species used to model open ocean dynamics) or choose a single average value to represent all species across the world's oceans. In part, this is due to a relatively poor understanding of diatom physiological ecology and a limited tool set for assessing in situ diatom physiological ecology. This research project will address this specific challenge by explicitly tracking metabolic pathways, measuring their regulation and determining their taxonomic distribution in a suite of environmentally significant diatoms using a state of the art, species-specific approach. A research expedition is set in the North Atlantic, a system that plays a major role in carbon cycling. Starting with a New England coastal shelf site, samples will be collected from the coast where diatoms thrive, to the open ocean and a site of a long term ocean time series station (the Bermuda Atlantic Time Series) where diatom growth is muted by nutrient limitation. This research takes advantage of new ocean observatories initiative (OOI) and time series information. Through the research expedition and downstream laboratory experiments, the molecular pathways of nutrient metabolism and related gene expression in a suite of environmentally significant diatoms will be identified. Data will be combined to predict major limiting factors and potentially important substrates for diatoms across marine provinces. Importantly, this integrated approach takes advantage of new advances in molecular and bioinformatics tools to examine in situ physiological ecology at the species-specific level, a key knowledge gap in the field.

地球上大约一半的光合作用是由海洋浮游植物产生的，海洋浮游植物是随着潮汐和洋流漂移的单细胞生物。在浮游植物中，硅藻进行了近一半的光合作用，对全球碳循环施加了深刻的控制。尽管它们很重要，但在理解硅藻在自然环境中如何发挥作用方面存在着令人惊讶的根本差距，部分原因是缺乏评估现场生理学的方法。这个项目的重点是应用一种强大的新方法，称为定量代谢指纹分析(QMF)，以解决这一知识差距，并在该领域检查物种特有的生理学。该项目将对海洋地球化学如何控制硅藻的分布、单个硅藻物种的代谢反应以及如何在硅藻物种之间分配代谢潜力提供变革性的见解，从而为海洋系统的结构和功能提供新的见解。首要目标是通过使用QMF跟踪硅藻生理学的变化，研究硅藻物种如何对从沿海到公海的海洋省份的生物地球化学变化做出反应。这项研究对于了解未来海洋浮游植物应对气候和环境变化的变化至关重要。此外，该项目的活动将包括支持一名研究生和博士后研究员，并向纽约市大都市区的不同中学年龄的儿童和教师以及国际扶轮女童子军的中学女孩提供艺术海洋学家计划(AOP)，预计每年将有60名儿童和30名教师参加。这些项目将促进多学科的动手学习，并将直接影响STEM教育，因为它针对纽约和里约热内卢的不同中学年龄组。在对培养菌株的实验室研究中，硅藻物种对营养限制的反应存在深刻差异。因此，不同物种对养分吸收、碳通量和埋藏的贡献可能不同。然而，海洋生态系统模型往往依赖于仅从一个物种中提取的生理属性，并在全球范围内应用这些属性(例如，用于模拟开放海洋动态的沿海物种)或选择一个单一平均值来代表世界海洋上的所有物种。这在一定程度上是由于对硅藻生理生态的了解相对较差，以及用于现场评估硅藻生理生态的工具集有限。这项研究项目将通过明确跟踪代谢途径，测量它们的调节，并使用最先进的物种特有方法确定它们在一组对环境有意义的硅藻中的分类分布，来解决这一具体挑战。一支研究探险队被安排在北大西洋，这是一个在碳循环中发挥重要作用的系统。从新英格兰海岸陆架站点开始，样品将从硅藻繁盛的海岸采集，到开阔的海洋和一个长期海洋时间序列站点(百慕大大西洋时间序列)，在那里硅藻的生长受到营养限制的抑制。这项研究利用了新的海洋观测站倡议(OOI)和时间序列信息。通过研究考察和下游实验室实验，将确定一套对环境有意义的硅藻中营养代谢和相关基因表达的分子途径。将结合数据来预测海洋各省硅藻的主要限制因素和潜在的重要底物。重要的是，这种综合方法利用分子和生物信息学工具的新进展，在物种特定的水平上原位检查生理生态学，这是该领域的一个关键知识空白。