This thesis explores open questions regarding molecular forms and interactions of natural and synthetic aromatic compounds present in soils and sediments.
Plant biomass-derived black carbon (biochar) generated through incomplete natural and anthropogenic combustion processes is a major source of aromaticity in terrestrial ecosystems. Chapter one represents a detailed account of...
“Active carbon” is a rapidly cycling soil organic carbon (SOC) fraction that acts as an energy and nutrient source for the microbial community. Dilute permanganate oxidation has been used to measure an “active carbon” fraction with the assumption that permanganate oxidation mimics enzymatic decomposition. Permanganate oxidizable carbon (PoxC) has become...
Deeply weathered soils in tropical rainforests and savannas are classified as Ferralsols according to the World References Bases for Soil Resources (WRB). Ferralsols are most nearly akin to the Oxisols order defined in the US Soil Taxonomy. The acidity, low cation exchange capacity, and strong phosphorus retention by the oxidic...
The bottleneck in the turnover of soil organic matter (SOM) is the conversion of large molecular compounds into smaller compounds that can be transported through a cell membrane of a microbe for processing. Once inside the cell, organic compounds can be converted into biomass or be respired. The microbial depolymerization...
Soil water repellency is one cause of rill soil erosion and overland flow that results in the loss of fertile topsoil. Previous research suggests that since microbial growth depends on temperature/moisture and follows diurnal and seasonal cycles, a biological mechanism would be able to explain the observed seasonality and climate...
Soils have a critical role in global carbon (C) cycling, containing one of the largest fast-cycling carbon stocks on earth. Robust representation of soil organic matter dynamics in Earth System Models is critical for future climate prediction. Current C cycling models assume that all C cycling in non-hydric (i.e. ‘upland’)...
Liquid manure lagoons are known to be sources of odor and environmentally damaging gas emissions. Land application of the manure slurry after storage can lead to detrimental nutrient runoff and leaching. Floating lagoon covers (biocovers) are one option for reducing emissions, but to date they have only been used to...
Liquid manure lagoons are known to be sources of odor and environmentally damaging gas emissions. Land application of the manure slurry after storage can lead to detrimental nutrient runoff and leaching. Floating lagoon covers (biocovers) are one option for reducing emissions, but to date they have only been used to...
Intimate associations with reactive metal species permanently protect soil organic matter (SOM) from microbial access and oxidation, contributing to the build-up of organic carbon (C) stocks in soils. It is increasingly recognized, however, that such associations can be reversible and that reactive metal species might even facilitate the oxidation of...
This study focuses on one widespread characteristic of poor soil quality: hydrophobic soil. Previous research has produced conclusive evidence to show that soil hydrophobicity is affected by soil organic matter (SOM) and soil water content (WC). Hydrophobicity that responds to changes in WC is a unique form of surface hydrophobicity...