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

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

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.