| Changing environmental conditions and disruptions are altering how streams and science classrooms are structured and how they function. Although stream spatial complexity has been theoretically emphasized, quantifying heterogeneity remains limited, especially in intermittent streams. In the Intermountain West United States, streams are experiencing earlier drying and the region is experiencing elevated wildfire conditions with climate change. Similarly, classroom active learning structures have been shown to benefit student learning, yet lecture dominates higher education practices. This dissertation explores the shared theme of linking theory and practice in two research areas: (a) biogeochemical patterns and processes in intermittent streams, and (b) introductory college science classroom behavior. In Part 1, I conducted sampling and quantified biogeochemical patterns and processes at fine-grain intervals (10 to 50 m) in two streams in southwestern Idaho, United States ,one unburned and one recently burned, as they dried. In contrast to expectations, streams showed weak evidence of in-stream evapoconcentration with drying. However, streams showed groundwater contributions increased with drying, which was more apparent in the burned stream. Organic carbon sourcing was highly variable in both streams. Then I quantified patterns using semivariograms and showed heterogeneity increased for dissolved inorganic and organic carbon but decreased for other nutrients with drying. Small solute semivariogram ranges detected (>150 m) may indicate that processing in intermittent headwater streams occurs at smaller scales than larger or perennial streams, and longer ranges in burned stream
xiiichemistry may support the telescoping ecosystem model, indicating disturbance like fire may increase patch size. In Part 2,I conducted observations of student and instructor behaviors in introductory science classrooms, instructor self-assessments, and anonymous student surveys to assess the extent of active learning implementation. Observed classroom behaviors were largely less active for instructors (71%) and students (81%)and mirrored national data. Little (>1%) student time was spent on core science skills such as predicting and presenting. Instructors, who reported using more active learning spent more time on the processes of science, and their students did more group work. Future teaching professional development recommendations include supporting instructors to facilitate active student behaviors and conducting student evaluations. Key Words: intermittent streams, biogeochemistry, evaporative processes, evapoconcentration, groundwater, allochthonous, autochthonous, stable water isotopes, heterogeneity, semivariogram, science education, active learning, ICAP framework, undergraduate STEM, teaching professional development, classroom behaviors, COPUS, classroom observations |