Open Access Kent State (OAKS)

The latest scientific reports published by the United Nations and the U.S. Global Change Research Program show evidence that environmental change is occurring. Gaining political momentum to deal with the problem is one issue, but beyond this hurdle is the need to communicate complex scientific information to the public so that they may help make informed decisions about responses to environmental change through the public decision-making process. Communicating this need to the public is challenged by the constraints of transcultural communication (Flower, 2008; Frost, 2013; Ding, 2014) and ideological conceptions of environmental collapse (Latour, 2018). In addition, people must be able to read and write in increasingly technical genres in order to make their voices heard regarding scientific issues surrounding environmental change (Brandt, 2001, 2015). The bar has been set higher for civic participation (Grabill, 2007; Simmons 2008), which precipitates a need for advanced literacies that support transcultural empathy, cooperative decision-making, critical analysis of scientific data, and organizational prototyping for future-oriented planning (Sauer, 2003; Potts, 2013; Gross, 2016). My dissertation research project is studying public communication surrounding development of one of the first freshwater offshore wind farms in North America, on Lake Erie. Methods for the study are mixed and include surveys, interviews, focus groups, and document analysis. Through this study, I will synthesize information surrounding contemporary environmental communication that will help push the next iteration of policy to better address environmental problems in ways that attend to the concrete manifestations of environmental change.

Bacteria attach to surfaces in aqueous environments and form biofilms; mixtures of cells embedded in a matrix of extracellular material. Biofilms are important to ecosystem function but have harmful effects in undesirable settings. One issue is persistence of pathogenic bacteria in biofilms, including Listeria. Listeria can survive in protected, multi-species biofilms and some strains are resistant to stress. The purpose of this study was to demonstrate antimicrobial activity of cranberry extract (CE) against Listeria innocua. To examine survivorship, L. innocua was suspended in serial dilutions of CE neutralized to pH 7.0. Samples were collected and plated on BHI agar. Subsequently, L. innocua was grown on glass beads submerged in BHI broth or 12.5% CE in BHI. L. innocua was inoculated and incubated for 48 hours. Samples were filtered, Live-Dead stained, and enumerated. In suspension, a 4 log reduction in L. innocua was observed after 18 hours in 12.5% and 25% CE. In the biofilm experiment, there was a > 1 log reduction in live and dead cells in biofilms in 12.5% CE. The formation of live microcells in the presence of CE was evidence of a stress response; poorly defined dead cells and debris were apparent with the dead stain. This study demonstrated inhibition of L. innocua by CE in suspension and biofilms. It did not distinguish between physiological stress and other mechanisms of biofilm inhibition. Future studies will examine mechanisms of biofilm inhibition and impact of CE on L. innocua in multispecies biofilms.

Northern latitudes are rapidly warming. As permafrost thaws, soil carbon (C) stocks are at risk of being released into the atmosphere, transitioning arctic systems from C sinks to sources. Soil microbial C metabolism is constrained by temperature, water and nutrients. Nutrients such as phosphate (PO43-), are in turn regulated by iron (Fe) geochemistry, but these interactions vary across redox conditions in arctic soils. Where present, poorly crystalline Fe (oxyhydr)oxides sorb PO43-, limiting its bioavailability. To assess microbial PO43- acquisition in the presence of Fe, we examined phosphorus (P) uptake by the microbial community in arctic soils in Abisko, Sweden. Mesh bags were filled with Fe-rich soil that was either saturated with PO43- or not saturated. Bags were incubated for one week along a thaw gradient representing different redox conditions. Preliminary results show that PO43- concentrations in microbial biomass are low, suggesting that microbes are acclimated to low P conditions and/or may be limited by nutrients other than P in arctic soils resulting in limited uptake of P molecules. Alternatively, PO43- liberated from microbial biomass by chloroform fumigation may have re-sorbed to soil Fe oxides, resisting detection. Continued analysis of soil Fe and P will further elucidate P storage pools.

Increasing temperatures in the arctic can cause permafrost thaw that radically changes hydrological and redox conditions in the soil. Redox sensitive minerals like iron (Fe) oxides can precipitate or dissolve in response to redox changes. Fe oxides control the cycling of nutrients such as phosphorus (P), a limiting nutrient in arctic soils, by adsorption. The effects of progressing permafrost thaw and resulting changing hydrology on redox conditions and Fe oxide crystallinity in arctic environments are still unknown. To investigate these complex interactions, an in situ incubation experiment was conducted along a permafrost gradient in arctic soils in Abisko, Sweden. Permafrost thaw in Abisko results in ground collapse and surface ponding. Mesh bags were filled with Fe rich sediments and buried in the top soil along a permafrost gradient for either one or eight weeks. Redox conditions were measured continuously along the gradient and incubated materials were analyzed with x-ray absorption spectroscopy (XAFS) for changes in Fe oxide crystallinity. Changes in total Fe and P concentration were determined by sequential extractions of the incubated material. Preliminary results show a change from oxic to anoxic conditions as permafrost thaw progresses and surface ponding occurs. XAFS show a shift toward ferrihydrite, a poorly crystalline Fe oxide, in the soils with surface ponding after eight weeks. Ferrihydrite has a high capacity for P sorption and might limit the bioavailability of this critical nutrient in thawing arctic soils and potentially limit plant growth and microbial activity.