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

该项目调查了决定微生物在哪里以及为什么在海洋上层数百米内将碳转化为生物质的效率最高的因素。微生物生长效率是一个重要的生态学参数，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中通过呼吸作用将有机碳转化为二氧化碳而损失的碳的比例。尽管它意义重大，但人们对微生物效率的驱动因素了解有限。由于难以直接测量用于生物质生产的能量，因此难以评估不同海洋微生物间的微生物效率差异。该项目使用新方法估计细胞内微生物能量转换，并将其与呼吸和初级生产等其他新陈代谢过程的测量进行比较。此外，研究人员还测量了加州当前生态系统中不同海洋环境的环境营养浓度、氧浓度、温度、pH和微生物群落结构，以包括在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、博士后学者和一批来自海洋科学历来代表性不足群体的本科生。该项目旨在确定导致海洋中微生物生长效率随光照和营养梯度变化的生态条件和微生物分类群。该项目使用了在加利福尼亚州中部和南部海岸的加州洋流生态系统的海洋研究考察中收集的数据，这是一个特征良好的异质区域，广泛代表着全球海洋中的关键生态系统。正在使用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--的创新组合来测量微生物生长效率。此外，研究人员使用机器学习技术提供预测性分析，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NSF的法定使命，并通过使用基金会的智力优势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.