SG: Microbial Community Coalescence: Disentangling Assembly Processes during Aquatic Mixing

微生物涵盖了地球上的大部分多样性，并负责维持各种生态系统的功能，如在动物的肠道、土壤和水中。这项研究的重点是了解控制微生物生活在哪里的过程，以及它们如何应对当地条件的变化。如果一棵树既能在环境条件下生存下来，又能在该位置与邻居的相互作用中生存下来，那么它就存在于该位置，而且它的幼苗可能会在新的环境条件下分散到新的位置。与树木不同，微生物经常作为整个群落迁移，并与其环境同步，经常与其他微生物群落及其各自的环境合并。例如，土壤颗粒在整个地貌上的风运动或人类握手导致了先前分离的微生物群落的新接触。这一过程被称为群落合并。两个水体的汇合是群落融合的一个明显例子，导致了一个新的、统一的环境，以前分开的微生物群落之间具有新的相互作用。这项研究将通过实验确定不同环境条件下水生微生物群落如何相互作用并对合并做出反应。该项目的目标是了解来自不同生境的微生物群落如何在群落合并下相互作用，具体目标如下：(1)描述实地微生物群落的成员及其在发生合并的三个不同水生环境中的活动。(2)在实验室中，跟踪微生物群落成员和活动对实验施加的合并的响应。(3)结合野外观察到的模式对实验数据进行分析。由于非生物和生物因素交织在一起，很难解开在合并事件后确定群落成员资格的机制。为了了解微生物的真实群落生态，有必要将最终决定哪些生物体持续存在，哪些不存在的环境因素和生物因素分开。为了解决这些基本的生态问题，研究小组开发了一种新的方法，直接测量环境因素和生物相互作用对联合群落的影响，无论是独立的还是组合的。该项目涉及群落生态学的基本概念，在水生系统的背景下传播大量微生物，并直接区分生物和非生物因素。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。

Microorganisms encompass most of the diversity on Earth, and are responsible for maintaining the function of various ecosystems, such as in the guts of animals, in soil, and in water. This research is focused on understanding processes that control where microbes live and how they respond to changes in local conditions. A tree exists in a given location if it can survive both the environmental conditions and interactions with its neighbors at that location, and its seedlings may disperse to new locations with new environmental conditions. Unlike trees, microbes frequently migrate as whole communities and in tandem with their environment, often merging with other microbial communities along with their respective environments. For instance, wind movement of soil particles across the landscape or human handshakes result in novel contact of previously separated microbial communities. This process is termed community coalescence. The confluence of two water bodies is a clear example of community coalescence, resulting in a new, united environment with novel interactions among the previously separate microbial communities. This research will experimentally identify how aquatic microbial communities interact and respond to the merger under different environmental conditions. The goal of this project is to understand how microbial communities from distinct habitats interact under community coalescence, with the following specific objectives: (1) Characterize the membership of microbial communities in the field and their activity at three distinct aquatic environments where coalescence occurs. (2) In the laboratory, track microbial community membership and activity in response to experimentally-imposed coalescence. (3) Analyze experimental data in the context of the patterns observed in the field. Unraveling mechanisms that determine community membership following a coalescence event is difficult, since the abiotic and biotic factors are intertwined. In order to understand the true community ecology of microbes, it is necessary to separate the environmental and biological factors that ultimately determine which organisms persist and which do not. To address these fundamental ecological questions, the research team developed a new approach to directly measure the effects of environmental factors and biotic interactions, independently and in combination, on coalesced communities. This project addresses fundamental concepts in community ecology, dispersal of a massive number of microorganisms in the context of aquatic systems, and directly disentangles biotic and abiotic factors.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.