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Thesis
Measuring Stable Isotopes to Trace Groundwater Transport of Dissolved Nitrogen in Seagrass Beds
University of West Florida Libraries
Master of Science (MS), University of West Florida
2020
Abstract
Submarine groundwater discharge (SGD) connects terrestrial groundwater to coastal surface waters through porous sediments. This research tracked dissolved nutrients as they traverse the subterranean estuary by measuring nitrogen stable isotope ratios in association with SGD inputs to nearshore beds of Thalassia testudinum. Variations of SGD-transported nutrients into the local environment (including porewaters and bottom waters) in which Thalassia is growing was investigated. Analysis was carried out for variations in elemental abundance and stable isotope composition of seagrass in areas receiving SGD compared to control areas in which no SGD is measured. Eight site locations were sampled within Florida's Gulf Islands National Seashore's Naval Like Oaks (NALO) Preserve for bottom-water nitrate, nitrite, ammonium and phosphate; physical water quality parameters (dissolved oxygen, specific conductivity, temperature, pH, and turbidity); δ15N in pore-waters and groundwater transect; and dissolved radon. Additionally, Thalassia testudinum IRMS analysis for δ15N to investigate SGD influences on N ratios and stable isotope composition in the local seagrasses, including spatial and tidal controls on any variability in water column chemistry and seagrass biogeochemistry. Overall, there was not a significant correlation between SGD inputs and the stable isotope values found in Thalassia. However, significant findings linking SGD to atmospheric precipitation and isotope ratios to seagrass growing seasons were unearthed. The results of this research could prove advantageous for policymakers and environmental managers as they deal with pollution and conservation efforts surrounding seagrasses.
Details
- Title
- Measuring Stable Isotopes to Trace Groundwater Transport of Dissolved Nitrogen in Seagrass Beds
- Resource Type
- Thesis
- Publisher
- University of West Florida Libraries; Pensacola, Florida :
- Format
- pdf
- Number of pages
- 104
- Copyright
- Permission granted to the University of West Florida Libraries to digitize and/or display this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires the permission of the copyright holder.
- Identifiers
- 99380090722606600
- Academic Unit
- Earth and Environmental Sciences
- Language
- English
- Awarding Institution
- University of West Florida; Master of Science (MS)
- Theses and Dissertations
- Master of Science (MS), University of West Florida