Research Starter Grant: Spatial Interactions between Microbes and Organic Matter across Different Scales

微生物是生物和化学过程的重要驱动力，这些过程控制着陆地生态系统中碳和植物养分的保留和损失。了解控制土壤微生物分布和活性的因素是很重要的。土壤中微生物的物理位置或空间组织对决定植物碎屑腐烂、养分释放和碳固存的速度至关重要。这项拟议的研究将研究植物类型(牧草与林木)和土壤干扰(放牧)的差异如何在多个空间尺度上影响土壤微生物、植物有机质和矿物质成分之间的相互作用，以及这些因素如何影响土壤中的碳和养分循环。这项研究将应用光谱学和显微技术的新进展，特别是二次离子质谱仪(SIMS)和纳米离子质谱仪(NanoSIMS)，在微米和纳米尺度上可视化和化学表征土壤中的单个生物和物理成分。将使用与NanoSIMS相结合的新方法以及更传统的酶和脂肪分析方法来衡量不同地点之间和土壤结构内微生物群落组成和活动的差异。微生物是生态过程中的关键因素，但也是生态系统中研究最少的组成部分之一。它们在土壤中的分布和相互作用的研究受到方法学的限制。现在，技术进步使我们能够更好地描述它们的栖息地和功能。这项研究的一个令人兴奋和具有挑战性的方面是整合不同空间尺度的数据，从土壤团聚体(厘米到毫米)到细菌细胞及其组成部分(微米和纳米)。这些新方法已经在医学和地球化学领域得到了成功的应用，但目前探索它们在土壤生物学和生物地球化学中的应用的研究还很少。这项研究的更广泛影响是多方面的。准确预测陆地生态系统将如何响应未来的气候和土地利用变化，特别是它们是吸收碳还是向大气释放碳，需要了解微生物、植物和土壤之间的生物和物理相互作用。土壤是最大和最具活力的陆地碳库之一，远远大于大气和陆地植被。因此，它们对大气中二氧化碳和其他温室气体的浓度产生重要影响。这项研究的另一个重要应用是管理有助于土壤肥力的微生物过程，以便可持续地生产粮食和生物能源。

Microorganisms are important drivers of biological and chemical processes that control the retention and loss of carbon and plant nutrients from terrestrial ecosystems. It is important to understand the factors controlling microbial distribution and activity in soil. The physical location, or spatial organization, of microbes in soil is critical in determining rates of plant detritus decay, nutrient release, and carbon sequestration. The proposed research will study how differences in plant type (pasture grasses versus forest trees) and soil disturbance (grazing) affect interactions between microbes, plant-derived organic matter, and mineral constituents of soils at multiple spatial scales, and how these affect carbon and nutrient cycling in soil. This study will apply new advances in spectroscopy and microscopy, in particular, secondary ion mass spectrometry (SIMS) and NanoSIMS, to visualize and chemically characterize individual biological and physical components in soils at the micro- and nanometer scales. Differences in microbial community composition and activity between sites, and within the soil architecture, will be measured using new methods coupled with NanoSIMS, as well as more conventional enzymatic and lipid analysis methods.Microorganisms are crucial agents in ecological processes, but are one of the least studied components of ecosystems. The study of their distribution and interactions in soils has been limited by methodological constraints. Technological advances now allow us to better describe their habitats and function. An exciting and challenging aspect of this study is the integration of data across different spatial scales, from that of soil aggregates (centimeters to millimeters) to that of bacterial cells and their component (micrometers and nanometers). These new methods have been successfully applied in the medical and geochemical fields, but there are only a handful of studies currently exploring their application in soil biology and biogeochemistry. The broader impacts of this research are many-fold. Accurate predictions of how terrestrial ecosystems will respond to future climate and land-use changes, and in particular, whether they absorb or release carbon to the atmosphere, require an understanding of the biological and physical interactions between microbes, plants, and soil. Soils are one of the largest and most dynamic terrestrial reservoirs of carbon, much greater than the atmosphere and land vegetation. Thus, they exert an important influence on atmospheric concentrations of carbon dioxide and other greenhouse gases. Another important application of this research is the management of microbiological processes that contribute to soil fertility for the sustainable production of food and bioenergy.