Achievement

Justin Poinsette collected soils from the Pumice Plain of Mount St. Helens to create a dataset of carbon and nitrogen content and isotope ratios. The results of these measurements indicated that atmospheric N deposition had a significant role in early soil development by providing the dominant form of N input across all three vegetation cover types. Furthermore, the results indicate that since the eruption, soil development has occurred through a shift from atmospherically-deposited N to microbially-deposited N, as indicated by the shift to a more positive soil 15N.