Impact of soil structure on microbial responses to environmental change

人类活动造成的环境变化和扰动可能对土壤中的基本活动产生破坏性影响，如对地球生态系统功能至关重要的地球化学循环。然而，对土壤结构（“土壤表型”）等关键物理变量对生态系统对此类扰动的反应的影响知之甚少。这些知识对于评估和预测土壤生态系统对长期扰动的恢复力至关重要。微生物驱动着土壤中的生态地球化学循环，并为土壤生态系统功能提供了理想的、易处理的指标。已知促进微生物对土壤扰动的恢复力的一个主要生物因素是变异，因为变异的生物体可能更好地适应改变的条件。最近通过埃弗里实验室和其他实验室的NERC资助项目取得的突破已经建立了一种新的生物变异形式，可以促进土壤系统中微生物的生存;即具有相同DNA组成的单个细胞之间的表型变异。现在广泛接受的是，这种遗传均匀的种群（非基因型异质性，NGH）内的变化，是重要的微生物在土壤中的生存。现在的主要挑战是了解土壤环境的类型如何随着时间的推移改变NGH对微生物生存的影响。具体而言，土壤具有不同尺度的空间结构，该项目将测试的假设，即物理异质性（土壤结构）调制NGH在土壤种群的影响。通过解决这个主要问题，这个奖学金将有助于描述土壤生态系统对环境扰动的恢复力。该项目将应用由跨学科合作支持的最先进的技术来解决这个问题，解决这些关键目标：NGH是否赋予结构化土壤的竞争优势？土壤结构是否影响压力土壤生态系统中NGH的长期演变？

Environmental change and perturbation due to human activities can have devastating impacts on essential activities in soils, like biogeochemical cycling, that are essential to the earth's ecosystem functions. However, the influence of key physical variables like soil structure ("the soil phenotype") on ecosystem responses to such perturbations is very poorly understood. Such knowledge is critical to appreciate and predict the resilience of soil ecosystems to perturbations over time. Microorganisms drive biogeochemical cycles in soils and provide ideal, tractable indicators of soil ecosystem function. A major biological factor known to promote microbial resilience to soil perturbations is variation, as variant organisms may be better adapted to the altered conditions. Recent breakthroughs through NERC-funded projects in the Avery laboratory and other laboratories have established a novel form of biological variation that promotes microbial survival in soil systems; that is, phenotypic variation between individual cells that have the same DNA composition. It is now widely accepted that this variation within genetically-uniform populations (non-genotypic heterogeneity, NGH), is important for microbial survival in soils. The major challenge now is to understand how the type of soil environment may alter the impact of NGH on microbial survival over time. Specifically, with soils having different scales of spatial structure, this project will test the hypothesis that physical heterogeneity (soil structure) modulates the impact of NGH in soil populations. By addressing this major question, this studentship will help describe the resilience of soil ecosystems to environmental perturbation. The project will apply state-of the-art technologies underpinned by interdisciplinary collaboration to tackle this problem, addressing these key objectives:Does NGH confer a competitive advantage in structured soils?Does soil structure affect long-term evolution of NGH in stressed soil ecosystems?