| dc.description.abstract | Understanding the transformation and transportation of organic carbon is important to elucidate carbon cycling within changing ecosystems. Biomass burning produces a continuum of pyrogenic organic matter (Py-OM) with unique chemical functionality dependent on temperature and the parent plant material. Spectroscopic analysis of lab produced Py-OM and pyrogenic water soluble organic matter (Py-WSOM) indicates that the Py-WSOM extracted from low temperature chars (200-650⁰) is dominated by carbon associated with polar functionality (-OH and C-O), most likely derived from the depolymerization and defragmentation of lignocellulose. Incubation experiments under aerobic conditions with unsterilized river water suggests that PyWSOM and associated pyrogenic biomarkers have turnover rates on the order of weeks to months, consistent with mixing and transport timescales for riverine systems. Therefore, the export of Py-WSOM from the aquatic system and its impacts on regional and global level carbon cycling may be heavily influenced by low-mid combustion temperature PyC. This study will aid in understanding the solubilization, degradation, and sequestration of terrestrial organic carbon in light of thermal alteration and vegetation replacement.
Texas coastal wetlands are dynamic tidal zones that have historically been dominated by salt marshes. Due to changes in regional weather patterns, this region has experienced warmer winters with a decrease in freeze intensity, allowing the black mangrove (Avicennia germinans) to expand local populations. For the past 2-3 decades, some of these ecosystems have experienced community shifts with A. germinans competing with native salt marsh plants for resources. This study quantifies plant biomass, organic carbon (OC) accumulation, and lignin accumulation for two salt marsh dominated wetlands, two A. germinans dominated wetlands, and one mixed salt marsh-A. germinans ecotone located along the Texas Gulf Coast, in order to understand the effect of vegetation replacement on OC accumulation. Annual and long term regional carbon accumulation for both A. germinans and salt marsh wetlands are significantly similar. Although carbon quantity is significantly similar the quality of carbon storage is different for A. germinans and salt marsh wetlands. | en |
