Do microbe-mineral interactions influence nitrogen cycle dynamics?

微生物-矿物质相互作用会影响氮循环动力学吗？

• 批准号: 2874119
• 金额: --
• 依托单位: University of Warwick
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2874119
• 关键词: Do; microbe; mineral; interactions; influence

The majority of organic N in soil is often held in the mineral-associated organic matter (MAOM) fraction of soil, which has slow turnover rates and is thought to be largely inaccessible to microbes and plants (Cotrufo et al. 2013). Partially decomposed plant material constitutes the particulate organic matter (POM) fraction in soil, which typically holds a smaller proportion of total organic N. Thus, MAOM can be viewed as a bottleneck to N-availability within the rhizosphere, with N mineralization rates depending on the structure of organic matter and its interaction with soil minerals and microbial communities. The underlying goal of this project is to investigate how ecosystem-microbe-mineral interactions drive nitrogen oxide fluxes from soils. While fluxes of nitrous oxide have been well quantified from ecosystems, fluxes of reactive nitrogen oxides are poorly studied owing to their highly reactive nature. Our incomplete understanding of the factors that control these fluxes has limited our ability to predict the air quality and climate impacts of soil N emissions. We aim to uncover the factors that determine nitrogen oxide fluxes in natural ecosystems (primarily woodlands and grasslands), using an approach that combines field experiments with state-of-the-art analytical capabilities and metagenomic analyses. Both N2O and NOy fluxes will be quantified to better determine edaphic factors responsible for both, and their potential interactions. Our hypothesis is that nitrogen oxide emissions are controlled by three factors: i) the activities of soil microbes that will vary depending on the ecosystem, the proportion of POM and MAOM, and the underlying soil mineralogy. To test our hypothesis, we will: (1) Determine the relationship between soil mineralogy and soil organic matter composition on soil outgassing of nitrogen oxides in field experiments; (2) determine how SOM-mineral interactions affect N availability and mineralization rates in different soil fractions and in varying ecosystems; (3) determine which soil fractions are targeted by N-mining microbes and which taxa produce the enzymes needed to mobilize N in those fractions.

土壤中的大多数有机物通常在矿物相关的有机物（MAOM）土壤中持有，该土壤的周转率缓慢，被认为在微生物和植物中很大程度上无法访问（Cotrufo等人，2013年）。部分分解的植物材料构成了土壤中的颗粒物有机物（POM），通常将其占总有机N的比例较小。因此，MAOM可以看作是根际内的N-矿化速率，n矿化速率取决于N矿化速率有机物的结构及其与土壤矿物质和微生物群落的相互作用。该项目的基本目标是研究生态系统 - 微生物矿物质的相互作用如何驱动氮氧化物的通量。虽然一氧化二氮的通量已经从生态系统中进行了很好的量化，但由于其高反应性的性质，反应性氮氧化物的通量对其进行了很少的研究。我们对控制这些通量的因素的不完全理解限制了我们预测土壤N排放量的空气质量和气候影响的能力。我们的目的是使用一种方法将现场实验与最先进的分析能力和元基因组分析相结合的方法来揭示确定天然生态系统（主要是林地和草原）中氮氧化物通量的因素。 N2O和NOY通量都将被量化，以更好地确定负责两者的质量因素及其潜在相互作用。 我们的假设是，氮氧化物的排放由三个因素控制：i）土壤微生物的活性会根据生态系统，pom和moom的比例以及潜在的土壤矿物学而变化。为了检验我们的假设，我们将：（1）确定土壤矿物质学与土壤有机物组成在土壤实验中氮氧化物的土壤中的关系； （2）确定在不同土壤部分和不同生态系统中，Som-Mineral相互作用如何影响N的可用性和矿化速率； （3）确定哪些土壤分数是由N开采微生物靶向的，哪些分类单元产生了动员N所需的酶的酶。