DISSERTATION RESEARCH: Metabolic Resource Partitioning: Scaling Microbial Physiology from Individual Activity to Ecosystem Function

人类的影响改变了景观内部和景观之间资源的流动。资源驱动人口动态，调节生态相互作用，是控制元素循环（如碳循环）的货币。在大多数情况下，这些循环是由微生物控制的。该项目侧重于水生微生物的生理和多样性，这些微生物利用陆地来源的溶解有机碳，在过去的30年里，湖泊和溪流中的溶解有机碳浓度不断增加，导致它们变成棕色。这种“褐变”不仅令人不快，而且代表了至关重要的地球生态系统功能的重大变化。本研究项目的总体目标是将微生物的多样性、生理学和代谢能力与环境中的资源转化联系起来。这些目标将通过关注群落内的资源专业化、微生物专家的丰度和活动以及它们如何影响生态系统功能来实现。拟议的研究项目将通过将特定微生物的多样性和生理学与生态系统功能，特别是碳循环联系起来，实现这些目标。为了实现这一目标，该项目将解决以下问题：1)微生物代谢活动的变化如何影响资源的转化率和命运？2)微生物多样性和代谢活动是否为资源专业化和资源转化提供了洞见？该项目将结合同位素标记资源跟踪和单细胞方法来了解微生物代谢活动和多样性。这些技术提高了追踪资源的能力，例如陆地溶解的有机碳，以及了解特定微生物的生理和多样性。因此，拟议的项目解决了微生物活动、生理和多样性与生态系统功能和资源命运的关系。

Human impacts have altered the movement of resources within and across landscapes. Resources drive population dynamics, mediate ecological interactions, and are the currency governing elemental cycles such as the carbon cycle. For the most part, these cycles are controlled by microorgranisms. This project focuses on the physiology and diversity of aquatic microorganisms that use terrestrially-derived dissolved organic carbon, which over the past 30 years has been increasing in concentration in lakes and streams, causing them to turn brown. Not only is this "browning" unpleasant to look at, it represents a major change in the function of critically important earth ecosystems.The overarching goals of this research project are to link the diversity, physiology, and metabolic capacity of microorganisms to resource transformations in the environment. These goals will be addressed by focusing on resource specialization within communities, the abundance and activity of microbial specialists, and how they affect ecosystem functions. The proposed research project will achieve these goals by linking the diversity and physiology of specialized microorganisms to ecosystem functioning, specifically the carbon cycle. To accomplish this, the project will address the following questions: 1) How does variation in microbial metabolic activity influence the transformation rate and the fate of resources? 2) Do microbial diversity and metabolic activity provide insight into resource specialization and the transformation of resources? The project will use a combination of isotope-labeled resource tracking and single-cell approaches to understanding microbial metabolic activity and diversity. These techniques provide increased ability to track resources, such as terrestrially dissolved organic carbon, and to understand the physiology and diversity of specialized microorganisms. As such, the proposed project addresses how microbial activity, physiology, and diversity relate to ecosystem functions and the fate of resources.