INTERACTIVE CONTROLS OF WATER TABLE POSITION AND PLANT FUNCTIONAL TYPES ON PEAT POREWATER CHARACTER IN NORTHERN BOG ECOSYSTEMS: IMPLICATIONS FOR CARBON CYCLING DYNAMICS

Northern wetlands, and particularly peatlands, have been shown to store around 30% of the world's soil carbon and thus play a significant role in the carbon cycle of our planet. Changes in climate are altering peatland hydrology and vegetation communities. These changes are possibly resulting in declines in the ability of peatlands to sequester carbon because losses through carbon oxidation and mineralization are likely to increase relative to C inputs from net primary production in a warmer, drier climate. However, the consequences of interactive effects of altered hydrology and vegetation on carbon storage are not well understood. This research evaluated the importance of plant species, water table, and their interactive effects on porewater quality in a northern peatland with an average pH of 4.54, ranging from 4.15 to 4.8. We assessed the effects of plant functional group (ericaceous shrubs, sedges, and bryophytes) and water table position on biogeochemical processes. Specifically, we measured dissolved organic carbon (DOC), total dissolved nitrogen (TDN), potential enzyme activity, organic acids, anions and cations, spectral indexes of aromaticity, and phenolic content. Our results indicate that acetate and propionate concentrations in the sedge-dominated communities declined with depth and water table drawdown, relative to the control and ericaceous treatments. DOC increased in the lowered water table treatments in all vegetation community types, and the peat porewater C:N ratio declined in the sedge-dominated treatments when the water table was lowered. The relationship between DOC and ferrous iron showed significant responses to vegetation type; the exclusion of Ericaceae resulted in less ferrous iron per unit DOC compared to mixed species treatments and Ericaceae alone. This observation was corroborated with higher mean oxidation redox potential profiles (integrating 20, 40, and 70 cm) measured in the sedge treatments, compared with the mixed and Ericaceae species treatments over a growing season. Enzymatic activities did not show as strong of a response to treatments as expected; the oxidative enzyme peroxidase and the hydrolytic enzyme phosphatase were the only enzymes to respond to water table, where the potential activity of both enzymes increased with water table drawdown. Overall, there were significant interactive effects between changes in vegetation and water table position on peat porewater composition. These data suggest that vegetation effects on oxidation reduction potentials and peat porewater character can be as important as water table position in northern bog ecosystems.

Living with Differences: From Everyday Fundamentalisms to Invitational Communication

This project examines fundamentalism understood as an everyday way of living poorly with difference. It demonstrates that the fundamentalist is not reducible to stereotypes of the terrorist, extremist, irrational madman, or religious zealot. All of these characterizations--common in mainstream media--depict the fundamentalist as them, and rarely, if ever, as us. Rather, this project understands fundamentalism in terms of fundamental interpretive constructs that constrain our ways of being-with others, skew our interpretive and responsive possibilities, distort our perceptions of difference, and affirm our poor treatment of others. Following Martin Heidegger's conception of the hermeneutic structure of existence, this dissertation calls attention to the ways in which such fundamentalisms filter our interpretation. Yet the hermeneutic character of existence also highlights the incompleteness of any particular frame of interpretation and indicates the possibility of alternative interpretive responses. The project turns to a feminist theological hermeneutic in order to indicate more hopeful and liberating ways of living with difference, ways that point beyond everyday fundamentalism toward invitational communication. Through new readings of familiar biblical narratives, this dissertation revisits the fundamentalisms that trigger these narratives in order to draw out an alternative feminist theological hermeneutic, or what is termed here an invitational hermeneutic. Each story offers unique ways of making sense of being-with and sharing the world with others of difference that redress the impoverished and fundamentalist forms of self-preserving care and understanding. By examining the well-loved stories of the Good Samaritan, Ruth and Naomi, Queen Esther, and the Apostle Paul and Lydia, the dissertation identifies interpretive and responsive possibilities that together issue an alternative hermeneutical invitation: to understand difference compassionately, to engage strangers and family members alike with rehabilitative care and concernful reticence, and to extend graceful hospitality to others. In these ways, the dissertation indicates possibilities beyond the horizon of fundamentalism, invitational possibilities of living and communicating with difference.