CAREER: Dynamics and Vulnerability of Mineral-Organic Associations in the Rhizosphere

该奖项全部或部分由《2021年美国救援计划法案》（公法117-2）资助。土壤是最大和最具活力的陆地碳库——储存的碳是大气和生物圈加起来的两倍多——因此直接响应和驱动全球气候。高达90%的土壤碳储存在与活性矿物密切相关的有机化合物中。这种矿物-有机结合（MOAs）可以保护碳化合物免受微生物或酶的攻击数百年至数千年。因此，目前的碳循环模型假设，MOAs及其所保护的碳一旦形成，对环境干扰相对惰性。然而，植物根和根际相关微生物具有众所周知的通过溶解和交换反应转化矿物质的能力。然而，这种根和微生物介导的反应对MOAs及其所保护的碳的影响仍然难以捉摸。更好地了解其他方面稳定的MOAs对根际过程的响应，对于改善这一巨大土壤碳库对环境变化脆弱性的预测至关重要。如果没有根驱动的MOA不稳定的稳健表示，模型将无法充分预测土壤碳-气候反馈。美国国家科学基金会CAREER项目的总体目标是发展对根际MOAs动态和脆弱性的机制理解，培养多样化、创造性和技术熟练的环境科学家，以应对21世纪最紧迫的环境挑战。该项目旨在(i)确定分子机制，（ii）定义生物地球化学驱动因素，以及（iii）评估根际土壤中由根驱动的MOA不稳定的环境控制。为了通过实验解决动态根际微环境中根-微生物-矿物的相互作用，本研究将开发新的原位剖面分析方法。这些研究目标与围绕重要的植物-微生物-土壤相互作用的研究在多个层面上的推广和教育活动密切相关。基于与当地合作伙伴的紧密合作和对跨学科教育的承诺，该项目将与霍利奥克社区学院合作，增加马萨诸塞大学环境科学学位项目中低收入和少数民族学生的代表性，并创建一门结合设计思维方法的新课程，为研究生和博士后提供解决当今社会面临的复杂环境挑战所迫切需要的创造性解决问题和协作技能。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). Soils are the largest and most dynamic terrestrial carbon reservoir - storing more than twice as much carbon as atmosphere and biosphere combined - and, thus, directly respond to and drive global climate. Up to 90% of soil carbon is stored in organic compounds intimately associated with reactive minerals. Such mineral-organic associations (MOAs) can protect carbon compounds against microbial or enzymatic attack for centuries to millennia. Consequently, current carbon cycling models assume that, once formed, MOAs and carbon protected therein are relatively inert to environmental disturbance. However, plant roots and associated microbes in the rhizosphere have a well-known ability to transform minerals through dissolution and exchange reactions. Yet, the impact of such root- and microbially-mediated reactions on MOAs and carbon protected therein remain elusive. A better understanding the response of otherwise stable MOAs to rhizosphere processes is critical to improving predictions of the vulnerability of this vast soil carbon reservoir to environmental change. Without a robust representations of root-driven MOA destabilization, models will insufficiently project soil carbon-climate feedbacks.The overall objectives of this NSF CAREER project are to develop mechanistic understanding of the dynamics and vulnerability of MOAs in the rhizosphere and to train diverse, creative, and technically skilled environmental scientists to meet the most pressing environmental challenges of the 21st century. The project aims to (i) identify the molecular mechanisms, (ii) define biogeochemical drivers, and (iii) assess environmental controls of root-driven MOA destabilization within rhizosphere soil. To experimentally resolve root-microbe-mineral interactions in dynamic rhizosphere microenvironments, this study will develop novel in-situ profiling approaches. These research objectives are closely aligned with outreach and education activities at multiple levels, structured around the study of important plant-microbe-soil interactions. Built on strong engagement with local partners and commitment to interdisciplinary education, this project will launch a collaboration with Holyoke Community College to increase representation of low-income and minority students in UMass's environmental science degree program and create a new course incorporating Design Thinking approaches, providing graduate students and postdocs with the creative problem-solving and collaborative skills urgently needed to solve the complex environmental challenges facing society today.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.