Dissertation Research: Iron redox dynamics as a driver of organic matter decomposition in humid tropical forest soils

全球土壤的碳含量是大气的两倍，因此了解全球碳循环对土壤有机碳积累和分解的影响因素至关重要。热带土壤可能含有高浓度的有机碳和铁矿物。在实验室里，这些铁矿物已被证明能与氧发生反应，分解微生物难以降解的有机化合物。目前的研究将测试这些反应是否会影响天然土壤中的土壤有机碳，这一发现将改变对土壤碳循环的理解，因为到目前为止，微生物被认为是大多数土壤有机质分解的主要原因。从这些实验中获得的见解可以改进描述土壤对全球碳循环影响的概念和数学模型，从而改进对气候变化的原因和后果的预测。了解由铁和氧驱动的有机物分解过程在自然生态系统中是否重要以及如何重要，也有助于土壤有机污染物的修复。本项目将支持对研究生和本科生以及社区志愿者的科学培训，研究结果将通过在线课程在当地学校传播。

Soils worldwide contain twice as much carbon as the atmosphere, so to understand the global carbon cycle it is important to understand the factors influencing soil organic carbon accumulation and decomposition. Tropical soils contain potentially high concentrations of both organic carbon and iron minerals. In the laboratory these iron minerals have been demonstrated to react with oxygen in a way that decomposes organic compounds that are otherwise difficult for micro-organisms to degrade. The current study will test whether these reactions affect soil organic carbon in natural soils, a finding that would transform the understanding of soil carbon cycling because up to now micro-organisms were thought to be primarily responsible for most soil organic matter decomposition. Insights from these experiments could improve conceptual and mathematical models that describe the influence of soils on the global carbon cycle, and thus improve prediction of the causes and consequences of climate change. Understanding whether and how organic matter decomposition processes driven by iron and oxygen are important in natural ecosystems could also contribute to remediation of soil organic pollutants. Scientific training of graduate and undergraduate students and community volunteers will be supported by this project, and findings will be disseminated in local schools and through online curricula.