Collaborative Research: Permafrost climate feedbacks: How interactions among plants, microbes, and minerals affect biogeochemical projections in a changing Arctic

北极正在以比地球上其他地方更快的速度变暖，导致北极生态系统的变化，可能影响全球气候。永久冻土是指至少连续两年保持冻结状态的土地。它位于北半球大约四分之一的陆地表面之下，含有与整个大气一样多的碳。永久冻土解冻导致优势植被的变化，并使永久冻土土壤中储存的碳容易分解，但现有的测量和模型对这些变化对全球碳循环的影响不一致。本研究项目探讨了微生物、矿物质及其与植被的相互作用如何影响永久冻土中碳的脆弱性。研究人员正在进行实验室和生长室研究，以调查微生物群落和永久冻土融化时碳的转化。他们正在将这些研究结果纳入地球系统模型，以了解对气候系统的反馈。这项研究正在填补关于永久冻土中储存的碳将如何影响地球碳循环的关键知识空白，这是为气候变化适应和减缓战略提供信息所迫切需要的信息。这个项目正在解决这样一个问题：植物和土壤（特别是矿物质和微生物）之间的反馈将如何影响北极土壤碳平衡，以应对全球变化？利用微生物测序和稳定同位素示踪等最先进的科学工具，研究人员正在进行(1)实验室培养，以确定土壤微生物群落和矿物学如何影响植物渗出物的命运以及融化的永久冻土中原生土壤有机质的脆弱性；(2)植物-土壤生长室中生态系统，以在环境和升高的二氧化碳下追踪地下植物沉积物进入永久冻土。这些发现正被用于开发和评估一种微生物模型，该模型可以处理植物-微生物-矿物质反馈的复杂性。该土壤模型正被整合到社区土地模型（CLM）中，以预测永久冻土融化对北极碳收支的影响。这项研究使永久冻土-气候反馈的长期预测变得更好。该项目通过博士助教奖学金、博士后研究和本科实验室教育，培养精通从微生物基因到全球元素循环等领域的下一代跨学科北极学者。此外，该项目还为多达50名早期职业研究人员提供陆地建模理论和实践方面的培训，特别关注北极系统。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。

The Arctic is warming at a rate faster than elsewhere on Earth, resulting in changes to Arctic ecosystems that may affect global climate. Permafrost is ground that remains frozen for at least two consecutive years. It occurs under approximately one fourth of the northern hemisphere's land surface and contain as much carbon as the entire atmosphere. Permafrost thaw leads to changes in the dominant vegetation and makes the carbon stored in the permafrost soil vulnerable to decomposition, but existing measurements and models disagree about the implications of these changes for the global carbon cycle. This research project investigates how processes mediated by microbes, minerals, and their interactions with vegetation affect the vulnerability of carbon in permafrost soils. The researchers are carrying out laboratory and growth chamber studies to investigate microbial communities and the transformations of carbon with permafrost thaw. They are incorporating the results of those studies into Earth system models to understand feedbacks to the climate system. This research is addressing critical knowledge gaps about how carbon stored in frozen permafrost will affect the Earth's carbon cycle, which is information urgently needed to inform climate change adaptation and mitigation strategies.This project is addressing the question: how will feedbacks between plants and soils (specifically minerals and microbes) affect arctic soil carbon balance in response to global change? Using state-of-the-science tools, such as microbial sequencing and stable isotope tracing, the researchers are carrying out (1) laboratory incubations to determine how soil microbial communities and mineralogy affect the fate of plant exudates and the vulnerability of native soil organic matter in thawed permafrost, and (2) plant -- soil growth chamber mesocosms to trace belowground plant deposits into permafrost soils under ambient and elevated CO2. These findings are being used to develop and evaluate a microbial-enabled model that can handle the complexity of plant -- microbe-mineral feedbacks. This soil model is being integrated into the Community Land Model (CLM) to predict the impact of permafrost thaw on the arctic carbon budget. This research enables better long-term projections of permafrost-climate feedbacks. The project is training the next generation of interdisciplinary Arctic scholars well-versed in scales ranging from microbial genes to global elemental cycles through PhD assistantships, postdoctoral research, and undergraduate laboratory education. In addition, the project provides training for up to 50 early career researchers on the theory and practice of land modeling, with a special focus on Arctic systems.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.