Collaborative Research: MSB: Microbial control of litter decay at the cellulose-lignin interface

这项工作的关键科学意义在于，在植物凋落物的长期降解和稳定过程中，微生物群落和化学相互作用的整合，因为目前还没有一个综合的知识表达在一个全面的定量框架中。凋落物分解是控制土壤肥力和固碳的主要因素。人们对了解土壤中碳含量增加或减少的条件越来越感兴趣，部分原因是土壤中含有的碳含量比大气中多，可以在全球变暖中起到缓和或加剧的作用。需要对驱动土壤碳固存、植物凋落物化学和分解过程中微生物群落组成和活性之间相互作用的生化机制进行综合的实地、实验室和模型研究，以确定这些关系。Moorhead和Sinsabaugh（2006）提出了一个将微生物动力学纳入分解过程的新模型——Guild分解模型（GDM），该模型对分解过程中控制植物凋落物化学、碳稳定和微生物群落组成和活性之间相互作用的机制提出了一系列具体假设。本研究将通过监测植物凋落物化学和微生物群落组成和功能的变化，在添加和不添加N的情况下模拟N沉降，对这些假设进行实验验证。稳定C同位素（13C）标记将进一步确定能够代谢植物凋落物特定化学成分的活性微生物的群落组成。该研究将为研究N沉降、CO2升高、植物群落组成变化和气候变化对凋落物分解和土壤碳固存的影响提供机制依据。在托莱多大学创意指导中心（CCI）的协助下，一项综合教育和推广计划将补充这项研究。在这个项目中，CCI将开发一个在线互动的树叶分解模型（iMold），为5-12年级的学生提供有关树叶分解的教育推广。参观者将能够看到整个凋落物分解的过程，或者不同的凋落物化学成分，沿着时间线看到时间、凋落物类型和环境如何与某种东西的衰变速度或慢速相关。教师和学生将能够在研究人员和其他学校的教室之间建立网络，使他们能够共享数据，提出问题，并在实验中进行合作。将建立一个交流中心，以便研究人员和教室可以在类似博客的环境中分享想法和结果，并提出问题。此外，该项目将为一些本科生和研究生提供培训。托莱多大学和肯特州立大学为科学界代表性不足的群体提供服务，他们将被招募到这个项目中。

The key scientific significance of this work is the integration of microbial community and chemical interactions during the long-term degradation and stabilization of plant litter because there has not yet been a working synthesis of this knowledge expressed in a comprehensive quantitative framework. Plant litter decomposition is the main control on soil fertility and carbon (C) sequestration. There is growing interest in understanding the conditions under which soils gain or lose C, in part, because soils contain more C than the atmosphere and could play either a moderating or exacerbating role in global warming. An integrated field, laboratory, and modeling study of the biochemical mechanisms driving interactions between soil C sequestration, plant litter chemistry, and microbial community composition and activity during decomposition is needed to define these relationships. Moorhead and Sinsabaugh (2006) developed a new model that incorporates microbial dynamics into the decomposition process, the Guild Decomposition Model (GDM), which has generated a series of specific hypotheses about the mechanisms controlling the interactions between plant litter chemistry, C stabilization and microbial community composition and activity during decomposition. The proposed research will evaluate these hypotheses experimentally by monitoring changes in plant litter chemistry and microbial community composition and function during decomposition, with and without added N to mimic N deposition. Stable C isotope (13C) labeling will further determine the community composition of active microorganisms capable of metabolizing specific chemical components of plant litter. This research will provide mechanistic insight into the impacts on plant litter decomposition and soil C sequestration from N deposition, elevated CO2, plant community composition shifts, and climate change. An integrated education and outreach program will complement this research, assisted by the University of Toledo's Center for Creative Instruction (CCI). For this project, the CCI will develop an online interactive Model Of Leaf Decomposition (iMold) to provide educational outreach about decomposition for grades 5-12. Visitors will be able to visualize the progress of the decomposition of litter as a whole, or different individual litter chemical constituents, along a time line to see how time, litter type, and environment relate to how quickly or slowly something decays. Teachers and students will be able to network between researchers and classrooms at other schools, enabling them to share data, ask questions, and collaborate on experiments. A communication center will be created so that the researchers and classrooms can share ideas and results, as well as ask questions in a blog-like environment. Additionally, this project will provide training for several undergraduate and graduate students. University of Toledo and Kent State University serve significant populations of underrepresented groups in science, and they will be recruited to this project.