Resource and Stress Interactions in Regulating Microbial Communities in a California Grassland Soil

资源与胁迫相互作用对加州草地土壤微生物群落的调节作用。从地表到地下水，土壤中富含微生物，这些微生物对整个地球都至关重要。 在过去，土壤微生物的研究主要是通过对植物营养丰富但微生物经历极端湿度和温度的表面进行采样来进行的。 相对而言，研究较少的是水分和温度应力减少的深度土壤微生物，但微生物更缺乏营养。 在整个深度剖面中，水分胁迫和营养的反作用如何影响土壤微生物的组成和功能？ 在这个项目中，土壤沿着一个深入研究的剖面在加州大学塞奇威克自然保护区将采样和水分加碳营养将在实验室中进行操作。 基于DNA的敏感技术将用于发现微生物如何随着营养的变化而变化，以及营养如何在土壤干燥时促进生存。 碳底物的稳定同位素（13 C）形式将通过微生物种群进行追踪，以发现哪些微生物群最活跃地处理营养物质。 这项研究很重要，因为虽然社会依赖土壤微生物来回收养分和生物降解污染物，但对表层和深层土壤微生物的功能了解甚少。 从这项研究中获得的知识将有助于理解污染物的命运和全球变暖的后果等广泛关注。 为了让其他人了解深层土壤微生物的重要性，将在研究现场建造一个解释性展示，成人团体和K-12学生将通过现有的教育访问计划与讲师一起参观。

Resource and Stress Interactions in Regulating Microbial Communities in a California Grassland Soil Patricia A. HoldenUniversity of California-Santa BarbaraFrom surface to groundwater, soil is rich in microbes that perform many functions essential to the entire planet. In the past, soil microbes have mostly been studied by sampling the surface where nutrients from plants abound yet microbes experience extremes of moisture and temperature. Comparatively less studied are soil microbes at depth where moisture and temperature stresses are reduced, but microbes are more starved for nutrients. How do the counteracting pressures of water stress and nutrition affect the makeup and function of soil microbes throughout a depth profile? In this project, soils along a well-studied depth profile at the UC Sedgwick Natural Reserve will be sampled and moisture plus carbon nutrition will be manipulated in the laboratory. Sensitive DNA-based techniques will be used to discover how microbes change with changing nutrition and how nutrition facilitates survival when soils are dry. Stable isotopic (13C) forms of carbon substrates will be traced through microbial populations to discover which microbial groups are most actively processing nutrients. This research is important because, while society depends on soil microbes to recycle nutrients and biodegrade pollutants, how surface and deep soil microbes function is only weakly understood. The knowledge gained from this research will help in understanding such broad concerns as pollutant fates and consequences of global warming. To educate others about the importance of deep soil microbes, an interpretive display will be constructed at the research field site where adult groups and K-12 students tour with docents through an existing educational visitation program.