Linking microbial biodiversity and ecosystem function in agricultural soils

该项目将评估农业管理做法对土壤微生物生态和功能的影响。最近，加拿大政府瞄准了增加可再生燃料生产的目标，以此来对抗该国对化石燃料的依赖。对燃料原料需求的增加使农业部门面临着为粮食、动物谷物以及生物燃料提供农作物的挑战。任何改变微生物群落结构的管理做法都是令人担忧的，因为它可能对植物生长和土壤健康以及土壤生态系统的长期可持续性产生潜在影响。此外，这些微生物的活性和生物多样性的变化可能会对整个土壤食物网产生级联影响，因为已知细菌和真菌是其基础。某些土壤类型或气候区域可能更适合生物燃料的长期农业生产，但不言而喻，土壤、植物和气候之间的相互作用将影响微生物群落的组成。因此，开始了解时空变异性如何影响土壤微生物群落动态是很重要的。本项目将使用定量聚合酶链式反应来评估植物种类和生物量去除对土壤微生物群落丰度和活性的影响。我们将针对与C和N循环相关的群体，包括氨氧化细菌(AOB)、氨氧化古生菌(AOA)、反硝化细菌、自由生活固氮菌、纤维素分解细菌以及总细菌和真菌。此外，我们将使用有针对性的元基因组学和后转录组学方法来检查这些系统中微生物功能群的多样性。最后，DNA稳定的同位素探测与元基因组学相结合将被用来识别与柳枝藤和芒属等生物能源作物残留物相关的微生物。增进我们对微生物群落动态的了解，对于目前正在进行的改进预测农田N2O排放的模型，以及预测哪些土壤和气候区域最容易在保持土壤健康和生态系统可持续性的同时，保持生物燃料生产的生物量的去除，可能是非常宝贵的。这些知识最终将有助于制定应对气候变化的战略。

This project will assess the impact of agricultural management practices on the ecology and function of soil microorganisms. Recently the Canadian government has targeted increased renewable fuel production as a way to combat the country's dependence on fossil fuels. The increased demand for fuel feedstock has challenged the agricultural sector to provide agricultural crops for food, animal grain, as well as biofuels. Any management practice that alters microbial community structure is a concern because of the potential impact that it could have on plant growth and soil health, and long term soil ecosystem sustainability. In addition, alterations in activity and biodiversity of these microorganisms may have a cascading impact throughout the soil food web, since bacteria and fungi are known to be at its base. It may be possible that certain soil types or climatic regions may be better suited for long term agricultural production of biofuels, however, it is understood that the interaction between soil, plants and climate will influence the composition of the microbial community. Therefore it is important to begin to understand how spatial and temporal variability influences soil microbial community dynamics. This project will use quantitative PCR to assess the impact of plant species and biomass removal on the soil microbial community abundance and activity. We will target groups associated with C and N cycles including ammonia oxidizing bacteria (AOB), ammonia oxidizing archaea (AOA), denitrifying bacteria, free-living nitrogen fixers, cellulolytic bacteria as well as total bacteria and fungi. Furthermore, we will use a targeted metagenomics and metranscriptomics approach to examine the diversity of functional groups of microbes in these systems. Finally, DNA-stable isotope probing combined with metagenomics will be used to identify microorganisms that are associated with residues from bioenergy crops such as switchgrass and miscanthus. Increasing our understanding of microbial community dynamics may be invaluable to current efforts that are underway to improve models that predict the emission of N2O in agricultural fields, and to predict which soil and climatic regions can most easily sustain biomass removal for biofuel production while maintaining soil health and ecosystem sustainability. This knowledge will ultimately contribute to the development of strategies to combat climate change.