Date of Award
6-2026
Degree Type
Thesis
Degree Name
Master of Science - Environmental Sciences
Department
Environmental Science
First Advisor
Jenny Rashall
Second Advisor
Matthew McBroom
Third Advisor
Julie Bloxson
Fourth Advisor
Mike Read
Abstract
Diatom assemblages and sediment geochemistry were used to evaluate environmental change and anthropogenic influence within the Sabine-Neches Estuary, Texas, USA. A transect of surface sediments and two sediment cores (North and South) were analyzed to assess both spatial and temporal variability in estuarine conditions and identify potential impacts of industrial activity, hydrological disturbance, and sediment reworking on the modern diatom communities.
The transect diatom assemblages exhibit a clear marine-to-brackish gradient dominated by the genera Coscinodiscus, Diploneis, and Eupodiscus, with localized anomalies at T10 (marine dominance in the northern estuary) and T6 (freshwater influence in the central estuary), likely reflecting episodic hydrologic variability and ship-induced mixing. Low and consistent lead (Pb) and zinc (Zn) enrichment factors show no correlation with diatom diversity, indicating that natural estuarine gradients rather than contamination primarily control modern assemblages.
The North Core preserves a predominately freshwater diatom assemblage with a variable component of brackish-marine fauna, though reduced diatom abundance and moderate elevated Zn–assemblage diversity relationships suggest sediment dilution and hydrologic input in the deeper part of the core. In contrast, the South Core shows highly
irregular assemblage patterns, weak geochemical relationships, and abrupt freshwater intrusions, consistent with sediment reworking, dredging, or storm-driven mixing throughout the majority of the core.
Overall, diatom assemblages effectively record estuarine environmental gradients, such as salinity, while highlighting localized disturbance within industrialized coastal settings.
Repository Citation
Springer, Kathryn A. and Rashall, Jenny M., "Investigating the Impacts of Industrialization on Diatom Assemblages in the Sabine-Neches Estuary, Texas, USA" (2026). Electronic Theses and Dissertations. 683.
https://scholarworks.sfasu.edu/etds/683
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