Years participated in RESESS:
Major: Biochemistry, Geology
Academic Affiliation: Wichita State University
Research Mentor: Julio Sepulveda
Communications Mentor: Katherine Kravitz
Steven began his journey with the geosciences at a young age with his fascination of Jupiter's Great Red Spot. During undergrad, He fell in love with complex system modelling and the interdisciplinary stance of the geosciences. Steven’s research focused on method development and implementation of reconstructing ocean and atmosphere carbon cycle paths during the middle-cretaceous using urea adduction and carbon isotopes. This served in conjunction with a large paleoclimate reconstruction consortium to understand the middle cretaceous and draw analogues to anthropogenic climate change. Steven hopes to attend graduate school for planetary geology.
Tracing Carbon Cycling in the Atmosphere and Oceans in the Middle Cretaceous
We present a high-resolution record of compound-specific stable carbon isotope data from short-chain—aquatic algae—and long-chain n-alkanes—terrestrial plants—preserved in sedimentary sequences from the Smokey Hollow #1 (SH1) core in the Grand Staircase Escalante National Monument in southern Utah. The study are covered by SH1 core was situated at the western margin of the Western Interior Seaway during the Cretaceous Ocean Anoxic Event (OAE2, ~94Ma.), and was characterized by high sedimentation rates and enhanced preservation of both marine and terrestrial organic matter.
Short- and long-chain n-alkanes were isolated and purified from branched and cyclic aliphatic hydrocarbons using an optimized urea adduction protocol, and δ13Cn-alkane was measured using a Thermo MAT253 GC-C-IR-MS. We use the δ13Cn-alkane from aquatic and terrestrial sources to better understand carbon cycle interactions in the oceanic and atmospheric carbon pools across this event. Our results indicate that the δ13C of terrestrial plants experienced a faster and more pronounced positive carbon isotope excursion compared to marine sources. We will discuss how these results can inform models of carbon cycle interactions between the ocean and the atmosphere during greenhouse climates, and how they can be used to trace possible sources of CO2.