Collaborative Research: Applying a novel approach to link microbial growth efficiency, function and energy transfer in the ocean

这个项目调查了决定微生物在哪里以及为什么在海洋的几百米深处最有效地将碳转化为生物质的因素。微生物生长效率是一个关键的生态参数，它描述了微生物生产生物质所需的能量，并定义了海洋微生物食物网通过呼吸将有机碳转化为二氧化碳而损失的碳比例。尽管其意义重大，但对微生物效率驱动因素的理解有限。由于难以直接测量用于生物质生产的能量，评估不同海洋微生物之间的微生物效率差异受到阻碍。该项目使用新方法来估计细胞内微生物的能量转换，并将其与其他代谢过程（如呼吸和初级生产）的测量结果进行比较。此外，研究人员还测量了加利福尼亚洋流生态系统中不同海洋环境的环境营养浓度、氧浓度、温度、pH值和微生物群落结构，并将其纳入解释和预测微生物碳流的数学模型中。此外，该项目还为新科学家提供教育和海上研究培训机会，包括研究生、博士后学者和一群来自历史上在海洋科学领域代表性不足的群体的本科生。本项目旨在确定海洋中微生物生长效率随光照和养分梯度变化的生态条件和微生物类群。该项目使用了在加利福尼亚中部和南部海岸加利福尼亚洋流生态系统的海洋研究考察中收集的数据，这是一个具有良好特征和异质性的区域，广泛代表了全球海洋中的关键生态系统。微生物生长效率的测量使用了两种新的基于放射性同位素示踪剂的技术，流式细胞术和微生物群落结构分析的创新组合。此外，研究人员使用机器学习技术提供预测分析，并将微生物群落结构、丰度、效率和环境条件联系起来。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。

This project investigates the factors determining where and why microbes are the most efficient at turning carbon into biomass within the upper several hundred meters of the ocean. Microbial growth efficiency is a critical ecological parameter that describes the energy required by microbes for biomass production and defines the proportion of carbon lost from marine microbial food webs through respiration—conversion of organic carbon into carbon dioxide. Despite its significance, there is a limited understanding of the drivers of microbial efficiency. Assessing microbial efficiency variation across different marine microbes is hindered by the difficulty of directly measuring the energy used for biomass production. This project uses new methods to estimate microbial energy conversion within cells and compare it to measurements of other metabolic processes such as respiration and primary production. Additionally, the researchers measure environmental nutrient concentration, oxygen concentration, temperature, pH, and microbial community structure from diverse oceanographic environments in the California Current ecosystem to include within mathematical models for interpreting and predicting microbial carbon flow. In addition, this project provides education and at-sea research training opportunities for new scientists, including graduate students, postdoctoral scholars, and a cohort of undergraduate students from groups historically underrepresented in the marine sciences. This project aims to identify the ecological conditions and microbial taxa that account for the variance in microbial growth efficiency along light and nutrient gradients in the ocean. The project uses data collected on an oceanographic research expedition in the California Current ecosystem along the central and southern California coast, a well-characterized and heterogenous region broadly representative of key ecosystems in the global ocean. Microbial growth efficiency measurements are being made using an innovative combination of two new radioisotope tracer-based techniques, flow cytometry, and microbial community structure analysis. In addition, the researchers use machine learning techniques to provide predictive analytics and link microbial community structure, abundance, efficiency, and environmental conditions.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.