Doctor of Philosophy (PhD)
The present research was done to deepen the understanding of natural organic matter (NOM) transformation and interactions in a diverse range of natural and engineered environmental systems, while also investigating the interactions of anthropogenic organic compounds (AOCs) sorption with engineered soil surrogate (ESS) systems. This was achieved by applying a range of spectroscopic techniques to monitor trends in complex NOM cycling within the environment at the soil/water interface to provide insight into the investigation of AOCs sorption to ESS systems.
The “reverse” approach, discussed in Chapter 2 and Chapter 3, studied large scale carbon dynamics in Barataria Basin, Louisiana wetland islands. The biogeochemical transformation of OM around three different islands was studied through spectroscopically determined indicators, total organic carbon analysis, and geophysical measurements. In Chapter 2, a protected island established two distinct dynamics of carbon accumulation and biological processing based on water movement around the island. In Chapter 3, multiple studied islands were statistically compared to show trends in carbon accumulation and biological processing based on exposure to water movement and position in Barataria Bay, LA.
In Chapter 4, the reverse approach continued by investigating seasonal compositional variation with the Mississippi River OM pool. Seasonal spectroscopic monitoring provided a detailed chemical composition dynamic and fluctuation of OM pool in the river. Seasonal OM compositional changes were statistically compared to both ecological variables (temperature, gage height, and water discharge) and biological components, tryptophan and tyrosine, detected in PARAFACs analysis. This statistical comparison established correlations between a number of variables to further identify trends in OM pool compositional dynamic during seasonal river conditions.
The investigation of AOC interaction with soil, discussed in Chapter 5, involved sorption studies of different ESS systems to three AOCs with a range of properties including polarity and functional groups. An investigation of sorption mechanisms and trends between these diverse AOCs and ESS systems provided insight into interactions between AOC functional groups and multi-tiered ESS systems. AOC functional groups influence sorption from interactions of aromatic Diazinon to non-specific hydrophobic interactions of terbufos. ESS functionalization also increased hydration and negatively influencing hydrophobic interactions.
Hayes, Michael Patrick, "Spectroscopic Study of Natural Organic Matter and Carbon Fluctuation in Environmental Systems" (2020). LSU Doctoral Dissertations. 5161.
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