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: 1558506
• 负责人: Sonya Dyhrman
• 金额: $ 44.77万
• 依托单位: Columbia University
• 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 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1558506&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，这是一种随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，但在了解硅藻如何在自然环境中发挥作用方面存在令人惊讶的根本差距，部分原因是缺乏评估原位生理学的方法。该项目侧重于应用一种强大的新方法，称为定量代谢指纹（QMF），以解决这一知识差距并检查该领域的物种特异性生理学。该项目将为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代谢潜力如何在硅藻物种之间分配提供变革性的见解，从而为海洋系统的结构和功能提供新的见解。总体目标是通过使用QMF跟踪硅藻生理学的变化，研究硅藻物种如何响应从沿海到公海的海洋省份的生物地球化学变化。这项研究对于了解未来海洋浮游植物对气候和环境变化的响应至关重要。此外，这项计划的活动将包括支持一名研究生和博士后研究员，并提供艺术海洋学家计划（AOP）给纽约大都会地区不同的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，预计每年将接触到60名儿童和30名教师。这些项目将促进多学科的实践学习，并将通过针对纽约州和RI州不同的中学年龄段群体，直接影响STEM教育。在培养分离物的实验室研究中，不同种类的硅藻对营养限制的反应存在很大差异。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力学的沿海物种），或者选择一个平均值来代表世界海洋中的所有物种。在某种程度上，这是由于对硅藻生理生态学的理解相对较差，以及用于评估原位硅藻生理生态学的工具集有限。该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异性方法确定它们在一系列环境重要硅藻中的分类分布，来解决这一特定的挑战。北大西洋是一个在碳循环中起着重要作用的系统。从一个新英格兰海岸陆架地点开始，样本将从硅藻繁盛的海岸收集，到开放的海洋和一个长期海洋时间序列站（百慕大大西洋时间序列）的地点，在那里硅藻的生长受到营养限制。本研究利用了新海洋观测站倡议（OOI）和时间序列信息。通过研究考察和下游实验室实验，将确定一组对环境有重要意义的硅藻的营养代谢和相关基因表达的分子途径。数据将结合起来预测各海洋省份硅藻的主要限制因素和潜在的重要底物。重要的是，这种综合方法利用了分子和生物信息学工具的新进展，在物种特异性水平上检查原位生理生态学，这是该领域的一个关键知识缺口。