DISSERTATION RESEARCH: Identifying Ecological Mechanisms Underlying Soil Microbial Functional Responses to Climate Change

土壤细菌和真菌受到当地降水制度的强烈影响，随着地球变暖，当地降水制度正在迅速变化。因为这些微生物通过生态系统调节养分循环，所以了解它们如何应对更潮湿或更干燥的条件是很重要的。德克萨斯州中部的爱德华兹高原是研究微生物对降水变化响应的理想“天然实验室”，因为在短距离内，年平均降雨量减少了40厘米，而土壤化学和植物群落没有变化。该项目利用实验室和现场实验沿着爱德华兹高原了解微生物种群和群落的变化如何影响土壤过程。完整的土芯已从爱德华兹高原干燥的西端移植到潮湿的东端，反之亦然。通过监测这些岩心中微生物群落组成随时间的变化，研究人员可以将微生物群落的变化与响应降雨的碳循环的变化联系起来。由于预计下个世纪美国许多地区的降水将急剧增加或减少，农民、牧场主和土地管理者需要了解植物和土壤群落将如何应对气候变化。这项研究将揭示微生物群落适应降雨模式变化的机制；研究结果将帮助当地土地所有者为降水变化做好准备。调查人员将让本科生，特别是那些来自代表性不足群体的学生，参与他们的实地研究。通过德克萨斯大学新生研究计划，本科生将有机会学习标准的野外生态学技术和新的下一代测序方法，用于识别环境样本中的细菌和真菌物种。

Soil bacteria and fungi are strongly influenced by local precipitation regimes, which are rapidly changing as the planet warms. Because these microorganisms regulate nutrient cycling through ecosystems, it is important to understand how they will respond to wetter or drier conditions. The Edwards Plateau in central Texas is an ideal 'natural laboratory' to study microbial responses to changes in precipitation regime, since mean annual rainfall decreases by 40 cm over a short distance while soil chemistry and plant communities do not change. This project uses both laboratory and field experiments along the Edwards Plateau to understand how changes in microbial populations and communities affect soil processes. Intact soil cores have been transplanted from the dry western end of the Edwards Plateau to the wet eastern end, and vice versa. By monitoring changes in microbial community composition in these cores over time, researchers can link changes in microbial communities with alterations in carbon cycling in response to rainfall. Since many regions of the United States are expected to experience dramatic increases or decreases in precipitation over the next century, farmers, ranchers, and land managers need to understand how plant and soil communities will respond to changing climates. This study will shed light on the mechanisms by which microbial communities acclimate to altered rainfall patterns; results will help local landowners prepare for changes in precipitation. The investigators will engage undergraduate students, and particularly those from under-represented groups, in their field research. Through the University of Texas Freshman Research Initiative program, undergraduates will have the opportunity to learn standard field ecology techniques and novel, next-generation sequencing methods for identifying bacterial and fungal species in environmental samples.