Ice-rafted sediment is deposited into the deep sea through abrasive and crushing processes causing the micromorphology of embedded quartz grains to alter. As quartz are high in silica and not easily eroded, their features could be paramount for accurate rebuilding of past ice-cap levels. Paleoclimate reconstructions require a quantitative analysis of ice-rafted debris (IRD)for heightened intervals. To gain further insight for paleoclimate estimations at Pleistocene sediment layers, the surface textures of quartz grains from the International Ocean Drilling Site U1537D, were analyzed by the Scanning Electron Microscope (SEM). These samples originate from the Dove Basin where countorite currents were influenced by Weddell Sea Deep Water flowing (WSDW), making this a unique reference site for examination. The goal of this study was to analyze shifts in glacial ice-caps through a dissection of quartz samples from Pleistocene intervals. This study's primary hypothesis claims that younger quartz grains at high IRD intervals display microstructures reflective of glacial fractures.

The International Ocean Drilling Program (IODP) Site U1537 is located in the Dove Basin off the coast of Antarctic Peninsula in a region known as “Iceberg Alley.” After an iceberg breaks off the Antarctic Ice Sheet, it travels northward towards “Iceberg Alley” via the Antarctic Circumpolar Current and melts, resulting in the iceberg-rafted debris (IRD) being deposited on the seafloor. Grain-size analyses of IRD from a Site U1537 sediment core allows us to track and recreate glacial and climatic changes in Antarctica over the last few million years. Here I will present the grain-size and weight percent IRD data from roughly three million years ago (MYA) in order to determine past Antarctic Ice Sheet mass loss. Recent climate models suggest that 3 MYA global surface temperatures were around 3ºC warmer than pre-industrial temperatures as a result of elevated greenhouse gas concentrations. As modern global temperatures continue to skyrocket at an unprecedented rate, it is vital that we understand past changes in the Antarctic Ice Sheet to better predict future changes in polar ice-sheet volume and global sea level over the next century.

Consumerism guided by linear economic principles which emphasize the extraction, utilization, and waste of material resources for financial capital gain has proven unsustainable as staggering resource exploitation and ecosystem degradation threatens a global sustainability crisis that cannot be reconciled within a linear society. This research proposes the paradigm shift to a nonlinear, circular society as a solution to the global sustainable development crisis; the circular economic model represents a zero-waste, closed-loop system that builds environmental, economic, and social capital while regenerating ecosystems. Further, my research identifies local sustainable business management as a key leverage point in supporting global Sustainable Development Goals. Data indicates that the integration of circular management practices into local small business models can act as a catalyst for the paradigm shift to a circular society. Case studies were conducted to analyze sustainable management practices amongst small businesses in Milwaukee. Representatives of local small businesses, community organizations, and sustainability experts were interviewed and surveyed in order to collect qualitative data regarding current sustainable management practices, sustainability challenges, and local infrastructure barriers. The subsequent comparative analysis addresses the infrastructure barriers that create sustainability challenges in Milwaukee, and indicates the necessity for both systemic reform and community action in the successful integration of circular economic principles. My research reflects that circular management applied at key leverage points within local small business models can create a ripple effect that significantly impacts global Sustainable Development Goals while serving as a catalyst for the paradigm shift to a circular society.

Post-fire stand, water balance, and hydrology are critical factors influencing vegetation recovery after a wildfire. Fire severity, and the amount of fire-induced tree mortality influence post-fire vegetation water cycling, as the rate of water movement from the soil to the atmosphere, depends upon the amount of live vegetation cover in the wake of wildfire. We examined the influences of fire severity on diurnal plant evapotranspiration (ET) rates, as measured by sapflow, by installing a network of 45 tree sapflow meters across the fire severity gradient of the 2011 Horseshoe Two Fire in the Chiricahua Mountains of southeastern Arizona. Unlike many high-severity fire sites, post-fire ET was high at shrub-land sites at high fire severity burns. In this study, post-fire ET was driven by plant species composition and forest stand structural complexity. The more drought-sensitive pines display a peak in transpiration early in the day during the peak of photosynthesis, closing their stomata midday as a water conservation strategy. Cypress and oaks maintain high sap velocity through sundown, demonstrating multiple peaks throughout the day. Our results suggest that plant functional traits and stomatal regulation of gas and water exchange play critical roles in explaining post-fire forest recovery trajectories. The ability of the cypress and oaks to keep their stomata open throughout the day and high transpiration rates may be a key mechanism explaining their success on high-severity sites relative to pines. These results provide key information for predicting post-fire plant communities and forest water cycling under future environmental change.