UMD Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/3

New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.

More information is available at Theses and Dissertations at University of Maryland Libraries.

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    THE EFFECT OF SUMMER STORM EVENTS AS A DISTURBANCE ON THE MOVEMENT BEHAVIORS OF BLACK SEA BASS IN THE SOUTHERN MID-ATLANTIC BIGHT
    (2019) Wiernicki, Caroline Jane; Secor, David H; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Storm events are a key disturbance in the Middle Atlantic Bight (MAB), driving thermal, hydrodynamic, and acoustic perturbations on demersal fish communities. Black sea bass are a model MAB species as their sedentary behavior exposes them to storm disturbances. I coupled biotelemetry with an oceanographic model, monitoring black sea bass movement behaviors during the summer-fall of 2016-2018. Storm-driven changes in bottom temperature (associated with rapid destratification) had the greatest effects on fish movement and evacuation rates, while the cumulative effects of consecutive storms had little to no observed effect. Storms also generate substantial noise, but the hearing frequencies of black sea bass are currently unknown. I conducted a quantitative literature analysis on fish hearing based on swim bladder elaboration, successfully classifying detected sound frequency ranges among fishes, including black sea bass. Climate change will likely alter the intensity of MAB storms, prioritizing research on their impacts to fish communities.
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    Hydrologic and Biogeochemical Storm Response in Choptank Basin Headwaters
    (2008) Koskelo, Antti; Fisher, Thomas R; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    This study quantified the effect of hydric soils on the hydrology and biogeochemistry of sub-watersheds across the Delmarva Peninsula. For hydrology, long-term data were compiled for 13 United States Geological Survey sites and evaluated for hydric soil effects. Results show that hydric soils reduce baseflow by increasing ponding and subsurface water storage, resulting in greater evapotranspiration. In contrast, hydric soils were unrelated to stormflow, which was instead driven by topography. During hourly sampling of 18 storms in the Choptank Basin, most forms of nitrogen and phosphorus increased in concentration due to erosion and re-suspension of sediments. Nitrate, however, decreased during storms due to dilution of nitrate-rich groundwater by runoff. Baseflow nitrate concentrations decreased with forested hydric soils, likely due to greater denitrification in forested hydric areas. Annually, much of the total nitrogen and phosphorus export occurred during storms, emphasizing the need to sample a wide range of flows to improve estimates of nutrient losses.