Dimensions: Collaborative Research: Community genomic drivers of moss microbiome assembly and function in rapidly changing Alaskan ecosystems

苔藓及其相关微生物是北极生态系统养分循环的重要组成部分，但对这些群落的许多方面了解甚少。苔藓相关的微生物是北方和苔原生态系统中支持植物生长的氮的主要来源，这意味着植物的生长速度可能对苔藓及其微生物的活动高度敏感，苔藓和它们的微生物将大气中的氮“固定”成一种对植物生长有用的形式。重要的是，固氮速率以复杂的方式取决于苔藓及其相关微生物群落（微生物组）的遗传多样性。然而，我们不知道哪些物种（苔藓或微生物）对固氮这一关键生物地球化学过程的速率变化负责，也不知道这些群落将如何对气候变暖做出反应。这项工作将测试遗传变异和固氮之间的关系，以模拟北纬高纬度生物多样性和生态系统功能对气候变化的响应。这项研究将提供关于环境变化如何影响北极生态系统的有用信息，并有助于深入了解苔藓及其相关微生物群的弹性。本研究的目的是确定苔藓遗传多样性对北方森林和北极苔原生态系统中两种广泛分布和丰富的苔藓的群落组成和固定n微生物群功能的影响。研究人员将采用种群基因组学、功能基因测序和稳定同位素测定阿拉斯加大尺度气候梯度的氮固定率，包括北极和北方长期生态研究（LTER）和国家环境观测网络（NEON）站点。这种跨学科的方法将使研究人员能够确定这个快速变化的生态系统中群落组合和功能变化的历史和当代驱动因素，并预测苔藓植物相关的固氮将如何在更温暖的气候中发生变化。因此，研究人员将使用高纬度系统中的苔藓-微生物相互作用作为模型，以告知我们在气候变化背景下生物多样性如何与生态系统功能相互作用的更广泛理解。

Mosses and their associated microbes are critical components of nutrient cycling in arctic ecosystems, yet many aspects of these communities are poorly understood. Moss-associated microbes are the major source of nitrogen to support plant growth in boreal and tundra ecosystems, meaning that rates of plant growth may be highly sensitive to the activity of mosses and their microbes, which "fix" nitrogen from the atmosphere into a form useful for plant growth. Importantly, the rates of nitrogen fixation depend in complex ways upon both the genetic diversity of the mosses and their associated microbial communities (microbiomes). However, we do not know which species (moss or microbial) are responsible for rate variation in this key biogeochemical process of nitrogen fixation, nor how these communities will function respond to a warming climate. This work will test for associations between genetic variation and nitrogen fixation in order to model the response of high northern latitude biodiversity and ecosystem function to climate change. The research will provide instrumental information about how environmental change will affect Arctic ecosystems and contribute insight into the resiliency of mosses and their associated microbiomes.The goal of the proposed work is to determine the effect of moss genetic diversity on the community assembly and function of the N-fixing microbiomes of two widespread and abundant mosses in boreal forest and arctic tundra ecosystems. The researchers will employ population genomics, functional gene sequencing, and stable isotope assays of N fixation rates along a large-scale climate gradient in Alaska that includes arctic and boreal Long-term Ecological Research (LTER) and National Environmental Observatory Network (NEON) sites. This interdisciplinary approach will enable the researchers to determine both the historical and contemporary drivers of variation in community assembly and function of this rapidly changing ecosystem, and predict how bryophyte-associated nitrogen fixation will change in a warmer climate. Thus the researchers will use moss-microbe interactions in high latitude systems as a model to inform our broader understanding of how biodiversity interacts with ecosystem function in the context of a changing climate.