Years participated in RESESS:
Download PDF [17.4 MB] »
Major: Environmental Science with a concentration in Geology
Academic Affiliation: University of Texas at El Paso
Research Mentors: Emily Graham and Diana Nemergut
Writing Mentor: Kathy Kelsey
Amanda grew up in El Paso, Texas and had a passion for science early on, constantly asking how things worked, why the Earth was the way it was, and collecting a large amount of rocks. With her mother being a teacher who engrained the importance of education in her, her passion turned into a successful academic career that led to a Bachelor of Science degree in Environmental Science-Geology from the University of Texas at El Paso. As an intern for RESESS, Amanda analyzed microbial extracellular enzyme activity and the structure of their communities after a burn event. She was able to sample, learn new lab techniques for measuring soil parameters and microbial DNA extraction, and provide data for future work.
Microbes control major biogeochemical cycles and can directly impact carbon, nitrogen, and phosphorus pools and fluxes in soils. However, many questions remain regarding when and where data on microbial community structure are necessary to accurately predict biogeochemical processes. In particular, it is unknown how shifts in microbial assembly processes may relate to changes in the relationship between community structure and ecosystem function. Here, we examine soil microbial community assembly processes and extracellular enzyme activity (EEA) at 4-weeks and 16-weeks after the Fourmile Canyon Fire in Boulder, CO in order to determine the effects of disturbance on community assembly and EEA. Microbial community structure was determined from 16S rRNA gene pyrosequencing, edaphic properties were determined using standard biogeochemical assays, and extracellular enzyme activity for β-1, 4-glucosidase (BG) and β-1, 4-N-acetylglucosaminidase (NAG) enzymes were determined using fluorimetric assays. Stepwise linear regressions were used to determine the effects of microbial community structure and edaphic factors on EEA. We determined that in 4-week post fire samples EEA was only correlated with microbial predictors. However, we observed a shift with 16-week samples in which EEA was significantly related to edaphic factors. Null derivation analysis of community assembly revealed that communities in the 4-week samples were more neutrally assembled than communities in the 16-week samples. Together, these results support a conceptual model in which the relationship between edaphic factors and ecosystem processes is somewhat decoupled in more neutrally assembled communities, and data on microbial community structure is important to most accurately predict function.