Conceptualizations of earth's surficial systems pose challenges to scientists, novice teachers, and students alike, because they are variable, non-linear, and dynamic. Developing scientific models of these systems allow users to visualize, manipulate, reason, and organize knowledge about the system under investigation. This dissertation is focused on two research strands using scientific modeling of surficial earth systems. The first strand is focused on a coastal ecosystem impacted by soil salinization and water availability. This study used topography, soil type, soil conductivity, and plant community to develop a conceptualized toposequence of this region to support our understanding of the dominant source of soil salinity. The second strand is twofold: novice understanding of scientific modeling and conceptual model development. The first study evaluates novice science teachers' approach to scientific modeling of a system which they have no prior knowledge about. Through observations, we assessed their science process skills, compared these results to novices and experts working with the same system, and found that novice teachers perform more like novices when faced with scientific investigations. This research will guide future teacher professional development programs to explicitly focus on science process skills and their role in scientific modeling. The second study characterizes the impact of an inquiry-based learning (IBL) module versus a traditionally structured laboratory exercise. The experimental groups were taught using IBL pedagogical techniques through manipulation of large-scale data sets, multiple representations, and a physical model. The control groups were taught traditionally. The groups were not significantly different prior to exposure to the lesson. Pre/post-expressed conceptual models indicate that the experimental group had greater increases in critical thinking. Written reports indicated they further gained in content knowledge, communication of findings, and experimental design. Overall results showed that teaching though IBL coupled with multiple representations had significant positive influence on student's conceptual model development. This synergistic dissertation between science and science education is a model for those wanting to pursue an academic career in geoscience education. This type of synergy between teaching and research allows for greater achievement in and outside the classroom ultimately improving overall education.

Understanding complex Earth systems is challenging for scientists and students alike, because of the characteristics (e.g. bifurcations, self-organization, chaotic response) that are associated with these systems. This research integrates two research strands which contribute to the scientific and pedagogical understanding of complex Earth systems. In the first strand, a method that characterizes volatile organic compounds (VOCs) as ecological proxies of soil microbial ecosystems was validated. Unlike other measures of microbial community structure (e.g. Biolog and FAME), VOCs are advantageous because they are non-destructive and can provide temporal and spatial data. Additionally they are rich sources of information that describe the microbial metabolism, community structure, and organic carbon substrates utilized by soil microorganisms. Statistical results indicate that the detected and identified VOCs were significant (p < 0.05) indicators of microbial community composition shift in soil microcosm studies. Geographical information systems (GIS) illustrates that VOCs varied with space and time in south Texas soils. The second strand focuses on a geoscience education study exploring student conceptual model development of complex Earth systems. The efficacy of multiple representations and inquiry was tested as the pedagogical strategy in upper and lower level undergraduate courses to support students’ conceptual model development of complex Earth systems. Comparisons in student performance were based on prior knowledge (low and high) and on exposure to the implemented pedagogy (control and experimental groups). Results indicate that an inquiry-based learning model coupled with the use of multiple representations had significant positive performance impacts on students’ conceptual model development and content knowledge. This dissertation model integrates science and education research and is particularly useful for graduate students who intend to pursue a career in academia and envision teaching as part of their professional duties. It allows for synergy between teaching and research to be achieved where the classroom becomes a laboratory for research. Ultimately, the research conducted in the classroom informs pedagogy and enhances scholarship. Graduates learn to bridge the gap between education and science departments where they become leaders in science who conduct cutting-edge scientific research and also value making a broader impact on society through enhancing public education.