Postdoctoral and Professional Researchers

Dr. Derrick Vaughn
Dr. Derrick Vaughn

I am an organic biogeochemist working as a Dean’s Postdoctoral Fellow on the transport of organic carbon through rivers globally, and its deposition along the coasts. Broadly, my research interests involve the study of land-ocean carbon dynamics and its changes associated with anthropogenic activity and modern climate change. I’m also interested in examining how carbon amount and character has varied over the last several thousands of years as understanding how carbon changed in the past can help better predict future changes with continued climate change. Recent work has focused on how contemporary anthropogenic land-use change (i.e. urban environments, agricultural practices) impact carbon export and character in fluvial environments. Central to my research is application of a diverse array of tools from modeling, to geochemical techniques (e.g. biomarkers, stable and radiogenic isotopes), as well as utilization of ultrahigh resolution mass spectrometry.

Dr. Jon Hawkings

My current research focuses on iron, phosphorus, nitrogen, silica and trace element (e.g. Mo, V, Mn) production, cycling and export from glacial environments, with my current interest centered on the Greenland Ice Sheet, the Patagonia Ice Fields and the Himalayas. These elements are considered essential nutrients for stimulating primary and secondary production, and therefore are potentially strengthening the biological pump in the oceans surrounding the Greenland and Antarctic ice sheets, and in other glaciated environments such as the Pacific Northwest and the coast of Patagonia. Understanding the sensitivity of nutrient fluxes to increased mass loss from glaciers is therefore important. It will allow us to ascertain the potential impact of rapidly melting ice sheets on downstream biogeochemical cycles not only in the future, but also during past glacial cycles (e.g. rapid deglaciations), and snowball earth events.

Dr. Anne Kellerman

My research interests revolve around organic matter (particularly dissolved), its sources, sinks and factors that control both its degradation and persistence. I am interested in a variety of aspects of organic matter biogeochemistry: the detailed characterization of chemical composition and controls thereof, the link between chemical composition and reactivity, the importance of intrinsic and extrinsic controls on organic matter persistence and reactivity, and the pathways that protect organic matter from microbial degradation. I am also interested in how the methods we use to characterize organic matter influence our interpretation of how it exists in situ. Such methods include absorbance and fluorescence spectroscopy, size exclusion chromatography, and ultrahigh resolution mass spectrometry. My research questions often pertain to the effects anthropogenic activities have on organic matter characteristics, such as how land-use and climate change affect dissolved organic matter composition and the link between composition and reactivity. My biogeochemical interests sprouted in lakes but have spread to any watery ecosystem and even soils. Publications