There have long been concerns about the negative impacts of recreational boating activity in the Indian River Lagoon system (IRL), especially in Mosquito Lagoon (ML), the northernmost part of the IRL. My research is focused on the impacts of boat wakes on intertidal reefs formed by the eastern oyster, Crassostrea virginica. There has been a 24% loss of oyster habitat in ML since 1943, where natural oyster reefs have been replaced by dead oyster reefs which do not serve the same ecological function. While there is anecdotal and correlative evidence that this loss is a result of boat wakes, no studies to date have confirmed dead reefs can be a direct result of boat wakes. Therefore, I addressed the following questions: (1) What wake heights are generated by a range of boat types, and (2) What amount of oyster movement and erosion occurs as a result of these boat wakes? A series of boat pass experiments addressed the first question; these results were utilized in experiments at Florida Institute of Technology's wave tank to observe sediment erosion and oyster movement as a result of specific wake heights. Model selection was used for both the field and wave tank experiments to determine which variables contributed most to explaining the wake heights, erosion, and oyster movement that occurred. Wake heights ranging from 0.05 cm to 20.80 cm were documented contacting the oyster reefs from the boat passes, with a mean of 2.95 cm. Boat type was less important than speed or distance when determining wake height. My wave tank results document that wake heights as small as 2 cm contacting oysters are capable of moving individual and clusters of oysters. Minimum distances for boats to travel in order to maintain wakes smaller than 2 cm at reefs are suggested for management purposes based on regression equations. This could minimize the amount of movement that occurs when oysters are subjected to boat wakes. The results of this study can help resource managers implement boating policies in Mosquito Lagoon, and contribute greatly to conserving this important ecosystem engineer.

Wave energy is a major driver for many coastal processes and influences wetland vegetation and shoreline stability. Coastal conservation and restoration projects often include wave climate estimations in the decision-making process for project design. The current method primarily used to estimate a project area's wave climate is the use of wind-wave models. These models use wind speed, wind direction, bathymetry, and fetch to estimate site-specific wave activity. However, these models neglect boat wake which is an important contributor to wave energy in fetch-limited environments. This study used site-specific wave measurements to compare wind-protected and open sites in Back Bay, Mississippi. Study results demonstrated that some protected sites experienced similar or even higher wave activity when compared to the open sites. These findings indicate that excluding boat activity from wave climate estimations could lead to an under-estimation of site-specific wave activity.

Coastal restoration has become a necessary and ubiquitous practice to enhance and conserve the many ecosystem services lost by marsh degradation. Wave climate is one of the most critical factors to consider for restoration projects. However, knowledge of the ways that waves affect marsh plants and the ecosystem services they provide is limited. The purpose of my dissertation was to improve the effectiveness of coastal marsh restoration by addressing the limitations and gaps associated with plant and ecosystem responses to waves through empirical research with three primary goals: 1) develop and test a low-cost wave gauge, 2) use it to compare above- and below-ground plant growth responses along a wave climate gradient, and 3) evaluate the effects of waves on nutrient removal in constructed marshes. I used three field and laboratory experiments to accomplish these goals. The low-cost wave gauge was developed using an Arduino microcontroller and various accessories. After development, the gauge was evaluated against a commercial gauge in a series of laboratory and field tests. Comparisons revealed over 90% agreement between the gauges and confirmed the applicability of the low-cost gauge. A total of thirty gauges were then constructed and deployed at sites within Mobile Bay, Alabama and surrounding tributaries. In addition to wave energy, plant data was also collected at each site, including above- and below-ground biomass, shoot density, height, and diameter. These data suggested that waves affect plant growth responses in ways not explained by the current plant response paradigm. For example, while greater diameter shoots best attenuate waves, shoot diameter declined with greater wave exposure in this study. This response was common among the study species. Other plant responses were species-specific. Finally, a field experiment was constructed to examine the main and interactive effects of sediment type, initial planting density, platform slope, and platform position at sites exposed to and protected from waves. Results from this experiment suggested that waves may potentially mitigate the effective removal potential of constructed marshes. Taken together, this dissertation advances research on plant responses to waves and provides new tools for land managers working on coastal restoration and conservation projects.