Sedimentological analyses of sediment traps and 289 years (1717-2006) of varved sediments from Shadow Bay (60.01°N, 159.18°W), Lake Chauekuktuli were compared to available hydrometeorological data in order to investigate basin response to hydroclimatic variability in southwest Alaska. On a subannual timescale, the characteristics of the coarse basal unit typical of clastic varves were controlled by spring snowmelt and runoff, while the fine-grained cap was shaped by fall and winter conditions. Coarse subannual laminations within the clay cap were associated with autumn storm activity and winter warming events brought about by the interplay between regional maritime and continental air masses. Biogenic silica (BSi) profiles show two annual peaks in siliceous algal deposition; the first occurred at the end of the spring freshet, the second in the late summer. On an annual timescale, varve thickness was dependent on total annual discharge (r2=0.75, n=43, p<0.0001), while maximum annual grain size was determined to be dependent on both maximum spring discharge (r2=0.63, n=43, p<0.0001) and total annual discharge (r2=0.61, n=43, p<0.0001). On interannual timescales, relationships between climate variables (temperature, precipitation, North Pacific (NP) and Pacific Decadal Oscillation (PDO) indices) and both regional discharge and varve thickness were insignificant. When the same data sets were analyzed on multidecadal timescales, regime shifts in varve thickness and total annual discharge coherent with shifts in NP and PDO indices were identified. Periods of increased varve thickness and total annual discharge were associated with warm PDO phases and a strengthened Aleutian Low. The 289-year varve record was used to reconstruct PDO dynamics prior to 1900. Multidecadal shifts were apparent throughout the 19th century, but were absent in the 18th century. This study provides insight into the linkages between regional climate, physical and biological deposition, and can be used to improve the interpretation of seasonal and annual-scale paleoclimate reconstructions for basins similar to Shadow Bay. This study also sheds light on the nature of multidecadal climate variability in the Pacific Northwest region prior to the instrumental record. / Thesis (Master, Geography) -- Queen's University, 2008-09-23 14:13:32.943

The six subsystems of Earth (atmosphere, hydrosphere, lithosphere, biosphere, cryosphere and anthroposphere) are complex and dynamic. Because all subsystems are linked, study from an independent perspective and a composite perspective is fundamental. Unfortunately, because of current instructional methods, students tend to consider these systems unrelated and use linear cause and effect models where little to no interaction occurs between different systems and the components. The simplistic and incorrect view of systems is the fundamental reason more education about Earth systems science is necessary in the K-12 curriculum. In this study, the Cause-MaP system of studying complex Earth systems in a private intermediate school in Texas was evaluated. The objective was to ensure that students are more aware of how Earth affects them and vice versa. An added benefit of the study was the opportunity to teach scientific reasoning. Students completed a pre-unit test to measure a priori knowledge. The students then worked through a modified Cause-MaP system in which they took notes in a structured table format; then each created a concept map. Students completed these steps for two subsystems: hydrosphere and lithosphere. The individual concept maps were used to assess knowledge and understanding of the individual systems by each student. At the end of the unit, students created composite concept maps which included each system they studied in this unit, to illustrate the interconnectedness of Earth systems. Based on the number of components and processes included, the students’ maps were evaluated to determine their understanding of the interactions between multiple Earth systems. The students’ maps were grouped based on the number of components and processes included in the concept maps. A post-unit test was also administered, which included two similar questions. The pre-unit test was completed again to check the overall progress of the students involved in this study. The students showed, with practice and encouragement from their instructor, that they recognize intersystem connections in complex Earth systems. With more integration of programs like these, students will become more proficient in recognizing system interactions.