Biogeochemical cycles are the fundamental component connecting all parts of the Earth system. Cycling of elements like carbon, nitrogen, and phosphorus involves multiple fluxes and reservoirs through all components of the broader Earth system. Student conceptions of these drawings can be measured through their drawings of various biogeochemical cycles, and the reservoirs they depict as well as the fluxes they illustrate can give us valuable insight into their systems thinking abilities. In this study, we analyzed undergraduate student sketches of the carbon, nitrogen, and phosphorus cycles and analyzed the number of fluxes and reservoirs depicted in each one as well as the types of reservoirs pictured. We performed statistical analysis to explore if there were differences between the number of fluxes and reservoirs shown between students in STEM and non-STEM fields. We also performed correlations and regression analysis to explore if the number of courses in various scientific disciplines was related to or predictive to the number of fluxes and reservoirs shown. Initial results show that students from STEM disciplines draw cycles with significantly more fluxes than their non-STEM peers. Additional analysis also shows that the number of chemistry and biology courses are most correlated to the number of fluxes and reservoirs depicted. Regression analysis suggests that the combination of the number of chemistry courses and geology courses may be an important predictor for the number of fluxes and flows shown in student diagrams. This suggests that interdisciplinary training may be important in the development of systems thinking in undergraduate STEM students, it also suggests that more work is needed to integrate systems thinking skills into introductory courses, particularly those that cater to non-STEM students.