Douglas Jerolmack is an assistant professor at the Department of Earth and Environmental Science, University of Pennsylvania, and a research associate of the National Center for Earth-surface Dynamics at the University of Minnesota. He received his Ph. D. in geophysics from MIT in 2006, and a B.S. in environmental engineering from Drexel University in 2001. His research focuses on the spatial and temporal evolution of patterns that emerge at the interface of fluid and sediment on Earth and planetary surfaces. Currently he is working on river delta evolution, and the nature of transport fluctuations in sedimentary systems.