2010-2011 Schlanger Fellow – Young Ji Joo

Young Ji Joo

Northwestern University

Relative Roles of Carbon, Nitrogen, Phosphorus, and Sulfur During Cretaceous Oceanic Anoxic Events’s











Cretaceous oceans experienced short-lived episodes of widespread anoxia, termed oceanic anoxic events (OAEs) by Schlanger and colleagues. Because OAEs were likely  driven by high primary productivity in surface waters, analysis of changes in nutrient cycles, as well as bottom water redox conditions that influence these cycles, can help to evaluate  mechanistic hypotheses for such events. This study seeks to test hypotheses linking the carbon, sulfur, nitrogen and phosphorous cycles. It is proposed that increased volcanism prior to the onset of the two most widespread OAE’s (OAE 1a and OAE 2) initiated a series of linked  biogeochemical processes that stimulated, and then diminished global primary production, resulting in geologically brief intervals of exceptional organic carbon burial. Although evidence from the shallow Western Interior seaway supports the specific mechanisms described herein, additional data from oceanic sites sampled in ocean drilling program cores is needed to confirm them.




I grew up in Busan, South Korea, a city famous for its baseball team, great sea foods, and beautiful beaches. I earned my bachelor’s degree in geology in 2003 at Seoul National University. My undergraduate research project focusing on studying chemical composition of Paleozoic sedimentary rocks and investigating their origins triggered my interests in pursuing researches on geochemistry of sediments. I received a master’s degree in geology in 2005 at Seoul National University. Currently I am entering my fourth year as a Ph.D. student in the Department of Earth and Planetary Sciences at Northwestern University working with Dr. Bradley Sageman. My main research, thus far, involves using carbon and nitrogen isotope analyses to investigate changes in nutrient cycles across Cretaceous Ocean Anoxic Event 2 and to understand triggering and terminating mechanisms of this catastrophic event.