Research Seminar - Hawkesbury Institute for the Environment

Seminar abstract: A conundrum exists in carbon cycle research. Will elevated atmospheric carbon dioxide increase plant production enough to mitigate climate change by sequestering carbon in soils? Or will rising temperatures stimulate decomposition rates and further amplify warming? The relative importance of these competing processes will largely determine the rate of global climate change in the coming decades. Predictive understanding is limited by a lack of empirical evidence from realistic field manipulations and detailed, mechanistic experiments. However, the potential to promote research on soil carbon cycle process feedbacks to climate change is expanding. In this talk Associate Professor Elise Pendall will present field-based evidence that elevated CO₂ can actually enhance C losses from soils, while warming can suppress them. Additional data from controlled environment chambers and incubation experiments will help explain why previous expectations are too simplistic. A key mechanism missing from most models is related to priming-enhanced decomposition of soil organic matter, which appears to be related to competition for nutrients between plants and soil microbes. Recent temperature sensitivity experiments additionally decouple the confounding influences of substrate availability and soil organic matter quality from microbial temperature responses. While carbon accounting is critical for policy makers and managers, improving mechanistic understanding is critical for creating realistic models.

Further information on Associate Professor Pendall(opens in a new window)