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

微生物包含了地球上大部分的多样性，并负责维持各种生态系统的功能，如动物的肠道，土壤和水中。这项研究的重点是了解控制微生物生存的过程以及它们如何对当地条件的变化做出反应。一棵树存在于一个给定的位置，如果它可以生存的环境条件和相互作用与邻居在该位置，它的幼苗可能会分散到新的位置与新的环境条件。与树木不同的是，微生物经常作为整个群落迁移，并与它们的环境一起迁移，经常与其他微生物群落沿着它们各自的环境。例如，土壤颗粒在景观中的风运动或人类握手导致先前分离的微生物群落的新接触。这个过程被称为社区凝聚。两个水体的汇合是群落合并的一个明显例子，导致了一个新的、联合的环境，在以前分离的微生物群落之间产生了新的相互作用。本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。本项目的目标是了解不同生境的微生物群落如何在群落聚结下相互作用，具体目标如下：（1）表征田间微生物群落的成员及其在三种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，以响应实验强加的聚结。(3)根据现场观察到的模式分析实验数据。由于非生物和生物因素交织在一起，因此很难解开在聚结事件之后决定群落成员资格的机制。为了了解真正的微生物群落生态学，有必要将最终决定哪些生物体存活而哪些生物体不存活的环境和生物因素分开。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来直接测量环境因素和生物相互作用对合并社区的影响。该项目涉及社区生态学的基本概念，水生系统中大量微生物的传播，并直接解开生物和非生物因素。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。

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.