BS, Kent State University, 2024, College of Arts and Sciences / Department of Biological Sciences

Wetlands act as a filter between the terrestrial land and a body of water, regulating the flux of nutrients between these. An overabundance of nutrients, such as phosphate, can lead to a harmful algal bloom (HAB), which is known to deplete oxygen from aquatic ecosystems and produce harmful toxins. The goal of this study was to determine the effect of different vegetation patches on the amount of bioavailable phosphorus, measured as soluble reactive phosphate (SRP), in both the surface water and sediment. We sampled surface water and sediment from Turtle Creek Bay located in Magee Marsh Wildlife Area, Ohio, where we identified four distinct vegetation patches: grasses, hardwoods, Typha spp. (cattail), and submerged aquatic vegetation (SAV). Results of this study showed that the SAV patch exhibited significantly less SRP than the other patches (p<0.05). However, there was no significant difference in SRP concentrations for the rest of the patches. Additionally, we experimentally incubated intact sediment cores sampled from a diagonal transect across Magee Marsh. The cores were incubated with four different SRP concentration treatments based on in situ SRP measurements. We found that at ambient SRP concentrations (4 ug/L), sediments released 455.2 ± 518.3 ug SRP/m2/d into surface waters, but when SRP concentrations in the surface water increased (to 18, 39, and 60 ug SRP/L), sediments removed SRP at increasing rates (-919.9 ± 278.7, -2062.3 ± 1001.61, -7378.5 ± 4267.1 ug SRP/m2/d, respectively).The increasingly negative mean flux rates suggest that these coastal wetland sediments can sequester increasing amounts of SRP as surface water concentrations increase.

Committee: Lauren Kinsman-Costello PhD (Advisor); Mark Kershner PhD (Committee Member); Andrew Scholl PhD (Committee Member); David Costello PhD (Committee Member) Subjects: Biogeochemistry; Biology; Conservation; Ecology; Environmental Science; Freshwater Ecology; Plant Sciences

Master of Science (MS), Ohio University, 2023, Environmental Studies (Voinovich)

Agricultural nutrient pollution is a significant cause of impairment in American surface waters. Wetland restoration projects in agricultural watersheds can provide an effective sink for excess nutrients and potentially improve downstream water quality. Ohio University has partnered with The Stream and Wetlands Foundation to conduct water quality monitoring during the restoration of Bloody Run Swamp, a wetland in a former agricultural field near Columbus, Ohio. This thesis serves as an analysis of the initial water quality impacts of this restoration project. The restoration of Bloody Run Swamp did not significantly impact total dissolved phosphorus, orthophosphate, TKN, or ammonia concentrations. In contrast, both nitrate/nitrate and total dissolved nitrogen concentration and loads were significantly reduced during construction. This may have been due to the dry weather during construction and the removal of drainage tiles from Bloody Run Swamp. Future water quality monitoring is needed to determine the long-term impacts of this restoration project.

Committee: Natalie Kruse Daniels (Advisor); Gregory Springer (Committee Member); Morgan Vis (Committee Member) Subjects: Agriculture; Aquatic Sciences; Biology; Earth; Ecology; Environmental Engineering; Environmental Management; Environmental Science; Environmental Studies; Geomorphology; Hydrologic Sciences; Hydrology; Limnology; Water Resource Management

MS, University of Cincinnati, 2004, Engineering : Environmental Science

Benthic sediment and pore water from the Little Miami River (LMR) near Spring Valley, Ohio was sampled before and after three storm events to determine the zone of influence for soluble reactive phosphorus (SRP). The zone of influence is the area in a vertical cross section through the streambed where the pore water SRP concentration changes during the passage of a runoff event. Benthic sediment samples (d < 0.85 mm sieved coarse sand and finer) from three depths (z=0, 15, 30 cm) and five in-stream locations at a single transect were analyzed for their ability to adsorb and desorb SRP. The LMR stream bottom was surveyed during each sampling event to detect changes in the cross-sectional shape of the river. Laboratory analysis of benthic sediment and pore water showed a significant decrease (α =5%) in benthic SRP concentrations with the passage of storm events at all sample points except the 15 and 30 cm near-bank samples. The zone of influence for the SRP concentration was found to extend throughout the benthic zone examined except in areas that are "protected" by a layer of depositional silts near the edge of the LMR. The river cross-section profiles taken during sampling events showed a scouring and re-shaping of the river bottom. Following the storm event, water column SRP concentrations increase from upstream sources and subsequently benthic sediment SRP increases in the zone of influence. The benthic sediments may confound future improvements from TMDL controls and watershed improvements with regards to nutrient removal. While fine benthic material serves as a sink during periods of high SRP in the water column, it may also serve as a source of SRP as the river column phosphorus concentrations decline.

Committee: Steven Buchberger (Advisor) Subjects: Environmental Sciences