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，导致北极生态系统发生变化，这可能会影响全球气候。永久冻土是指连续冻结至少两年的土地。它位于北半球约四分之一的陆地表面之下，碳含量相当于整个大气的碳含量。多年冻土融化导致了主要植被的变化，并使储存在多年冻土中的碳容易分解，但现有的测量和模型对这些变化对全球碳循环的影响意见不一。这项研究项目调查了微生物、矿物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碳在永久冻土融化过程中的变化。他们正在将这些研究的结果纳入地球系统模型，以了解对气候系统的反馈。这项研究正在解决有关储存在冻土中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缓解战略提供迫切需要的信息。该项目正在解决以下问题：植物与土壤(特别是矿物和微生物)之间的反馈将如何影响北极土壤的碳平衡，以应对全球变化？使用最先进的工具，如微生物测序和稳定同位素示踪，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融化的永久冻土中植物渗出物的去向和本地土壤有机质的脆弱性，(2)植物-土壤生长室中围隔，以追踪环境和高浓度二氧化碳下地下植物沉积到永久冻土中的情况。这些发现正被用来开发和评估一种微生物驱动的模型，该模型可以处理植物-微生物-矿物反馈的复杂性。这个土壤模型正在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。这项研究能够更好地对永久冻土气候反馈进行长期预测。该项目正在通过博士助学金、博士后研究和本科实验室教育，培训精通从微生物基因到全球元素循环的下一代跨学科北极学者。此外，该项目为多达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NSF的法定使命，并通过使用基金会的智力优势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.