Collaborative Research: LiT: ETBC: Plant-microbe feedback mechanisms affecting decomposition and nutrient availability and interactions with climate change

草原生态系统占地球陆地面积的30%以上，为放牧等广泛的农业活动提供了资源基础。草原对气候变化很敏感，因为它们存在于炎热干燥天气常见、降雨不可预测的地方，而且它们的植物群落可能会因气候和大气中二氧化碳浓度的上升而迅速变化。草原土壤含有大量的长寿命碳，可以缓冲气候变化，或者如果这些碳被释放到大气中，就会加速气候变化。土壤微生物群落是土壤碳吸收或损失的最终驱动因素。该项目研究了在怀俄明州夏安附近的草原上进行的一项正在进行的、最先进的、可操纵的气候变化实验中，植物-微生物相互作用如何调节土壤碳循环，即草原加热和二氧化碳富集（PHACE）实验。30个样地暴露于气候条件的组合，包括预计在21世纪末之前发生的变暖和二氧化碳条件，以及改变的降水。该实验的一个重要组成部分是比较具有不同植物群落（包括入侵物种）的原生草地和受干扰草地之间的碳和养分循环。应用分子和同位素方法的实验室和生长室实验将检验从实地观察和测量中产生的具体假设。该项目预计将减少与土壤养分、生物群落和气候变化之间相互作用有关的不确定性，从而改进对未来大气二氧化碳浓度和相关变暖效应的预测。该项目将通过每年在PHACE地点举办田间日活动并在通俗报刊上发表文章，向关心气候变化、干扰和杂草入侵对牧场生产力影响的农业资源管理机构、牧场主和土地所有者提供帮助。将通过将土壤数据纳入综合数据库来促进跨站点协作和数据综合。该项目将为来自代表性不足群体的两名研究生、几名本科生和两名博士后科学家提供强有力的跨学科培训。参加怀俄明大学自然科学硕士学位课程的在职中学科学教师将被邀请到现场进行实践课程开发，少数民族高中学生将得到指导。科罗拉多州立大学新成立的夏季土壤研究所（http://soilinstitute.nrel.colostate.edu）将带学生到PHACE现场进行采样和分析。

Grassland ecosystems comprise over 30% of the Earth's terrestrial surface, and provide a resource base for extensive agricultural activities such as ranching. Grasslands are sensitive to climate change because they exist where hot, dry weather is common and rainfall is unpredictable, and because their plant communities may rapidly shift in response to rising climate and atmospheric CO2 concentrations. Grassland soils contain large stores of long-lived carbon, which could either buffer climate change, or accelerate it if this carbon is released to the atmosphere. Soil microbial communities are the ultimate drivers of soil carbon uptake or loss. This project investigates how plant-microbe interactions regulate soil carbon cycling within an ongoing, state-of-the-art, manipulative climate change experiment in grasslands near Cheyenne, Wyoming, the Prairie Heating and CO2 Enrichment (PHACE) experiment. Thirty plots are exposed to combinations of climate conditions, including warming and CO2 conditions expected to occur before the end of the 21st century, and altered precipitation. An important component of the experiment is the comparison of carbon and nutrient cycling between native and disturbed grasslands with distinct plant communities, including invasive species. Laboratory and growth chamber experiments applying molecular and isotopic methods will test specific hypotheses generated from observations and measurements in the field. This project is expected to reduce uncertainties related to interactions between soil nutrients, biological communities and climate change, leading to improved predictions of future atmospheric CO2 concentrations and associated warming effects.This project will reach out to agricultural resource management agencies, ranchers and landowners who are concerned about impacts of climate change, disturbance and weed invasion on rangeland productivity, by conducting annual Field Days at the PHACE site and publishing articles in the popular press. Cross-site collaboration and data synthesis will be promoted by incorporating soil data into a comprehensive database. The project will provide strong interdisciplinary training to two graduate students, several undergraduates, and two postdoctoral scientists from under-represented groups. In-service middle school science teachers participating in the University of Wyoming Master's of Science in Natural Science degree program will be invited to the field site for hands-on lesson development, and minority high school students will be mentored. The new Summer Soil Institute at Colorado State University (http://soilinstitute.nrel.colostate.edu) will bring students to the PHACE field site for sampling and analyses.