Aaron Diefendorf

Aaron Diefendorf is a Professor of Geosciences at the University of Cincinnati within the College of Arts and Sciences. His research focuses on the application of organic geochemical techniques to address questions in paleoclimatology, biogeochemistry, and environmental science. He directs the University of Cincinnati Stable Isotope Laboratory, where his team analyzes biomarkers from sedimentary archives to reconstruct past climate and environmental conditions.

Dr. Diefendorf's research interests center on isotope geochemistry, biogeochemistry, organic geochemistry, biomarkers, and stable isotope geochemistry. His work particularly emphasizes plant-derived biomarkers such as leaf waxes (n-alkanes) and diatom-derived highly branched isoprenoids (HBIs) as proxies for reconstructing past hydrological conditions. He investigates how these biomarkers form in modern ecosystems, their preservation in sediments, and their application to paleoclimate reconstruction across various timescales from the Holocene to deep time. His research spans diverse environments including midcontinental North America, the Sierra Nevada, Falkland Islands, and Arctic regions.

The analysis of his recent publications reveals a strong focus on methodological development for biomarker analysis, seasonal and spatial variability studies of biomarker production, and their application to specific paleoclimate questions. His work increasingly integrates multi-proxy approaches, combining plant wax and diatom biomarkers with other geochemical indicators to provide more robust paleoenvironmental reconstructions. Recent research shows growing interest in applying these techniques to understand hydrological changes during significant climate transitions including the Little Ice Age and Holocene.

• Extensive research on plant wax n-alkanes as paleohydrological proxies
• Pioneering work on diatom-derived HBIs for paleoclimate reconstruction
• Studies on biomarker production in modern ecosystems to improve paleo-interpretations
• Applications to major climate events including the Paleocene-Eocene Thermal Maximum
• Development of analytical methods for biomarker extraction and analysis

Dr. Diefendorf has established productive collaborations across multiple institutions and disciplines, working with researchers in geology, biology, environmental science, and climate science. His research has been supported by multiple NSF grants, including collaborative projects focused on biomarker development and paleoclimate applications. He actively engages in public science communication, including outreach at local farmer's markets in the Cincinnati community.

His laboratory work focuses on the Stable Isotope Laboratory at the University of Cincinnati, where his team processes sediment samples, extracts organic compounds, and analyzes isotopic compositions using state-of-the-art instrumentation. The lab serves as a hub for interdisciplinary research, training graduate and undergraduate students in geochemical techniques while advancing methodological approaches in biomarker paleoclimatology.