Dissertation Research: Disentangling temperature controls on turnover of old, nitrogen-rich soil organic matter

土壤有机质是陆地上最大的碳和氮储存库，是地球上所有生命的两个主要组成部分。较高的温度可能会加速微生物对土壤有机质的分解，导致碳和氮的动态发生重大变化。在其他影响中，土壤有机碳在大气中转化为二氧化碳可能会加剧气候变化。但只有在微生物能够接触到有机物质的情况下，变暖才会加速土壤有机质的分解。矿物对土壤有机质的稳定作用是土壤有机质对微生物有效性的主要控制因素，也是了解土壤碳、氮对气候变暖响应的关键。这里提出的方法使用了一个简单、现实的土壤培养实验，涉及用同位素标记的植物材料，以揭示气候变暖的影响。这项实验通过使用真实的植物材料和土壤，对碳输入和其他驱动变量(温度、湿度等)进行了严格控制，从而改进了以前的工作。这些结果将提高我们预测未来气候变化的能力，并促进我们对全球碳和氮循环的理解。在整个研究过程中，结果将通过对本科生的指导和在科学会议上的陈述来传播。调查人员将与科罗拉多州立大学学术进步中心合作，招募一名低收入、第一代残疾学生参加一个新的本科生研究项目。该学生将参加一系列旨在提高科学素养和批判性思维的研讨会，并将参与该项目的方方面面。在这项工作达到顶峰时，结果将在第六届土壤和沉积有机质稳定和不稳定国际研讨会以及科罗拉多前沿学生生态学研讨会上公布。通过参加为不同受众设计的会议，成果将被广泛提供，并纳入多个领域的研究。

Soil organic matter is the largest land reservoir of carbon and nitrogen, the two major building blocks of all life on earth. Warmer temperatures may accelerate the breakdown of soil organic matter by microorganisms, causing major shifts in the dynamics of carbon and nitrogen. Among other impacts, the transformation of soil organic carbon into carbon dioxide in the atmosphere could intensify climate change. But warming will accelerate soil organic matter breakdown only if microbes have access to it. Stabilization of organic matter in soils by minerals is the dominant control on the availability of soil organic matter to microbes and so is the key to understanding how soil carbon and nitrogen will respond to warming. The approach proposed here uses a simple, realistic soil incubation experiment involving plant material labeled with isotopes to reveal the effects of warming. This experiment improves upon previous work by enabling tight control over carbon inputs and other driving variables (temperature, moisture, etc.), while using real plant material and soils. The results will improve our ability to predict future climate change and advance our understanding of the global carbon and nitrogen cycles. Throughout this study, the results will be disseminated through the mentoring of undergraduate students and presentations made at scientific meetings. The investigators will work with the Academic Advancement Center at Colorado State University, to recruit a low-income, first-generation and disabled student into a new program for undergraduate research. This student will take part in a series of workshops designed to improve scientific literacy and critical thinking and will be involved in every aspect of this project. At the culmination of this work, results will be presented at the 6th International Workshop on Soil and Sedimentary Organic Matter Stabilization and Destabilization and at the Colorado Front Range Student Ecology Symposium. By attending meetings designed for different audiences, the results will be made broadly available and integrated into research in multiple fields.