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Full-Text Articles in Earth Sciences
The Role Of Sediment Resuspension In Estuarine Inorganic Nutrient Cycling, Kirsten Jo Ayres
The Role Of Sediment Resuspension In Estuarine Inorganic Nutrient Cycling, Kirsten Jo Ayres
Theses and Dissertations
Time-scaling of estuarine inorganic nitrogen cycling contains many assumptions due to biogeochemical interactions. Nitrogen, often a limiting factor for primary production, is transformed and utilized by many estuarine organisms. Inorganic nitrogen is especially high in porewater. High nutrient pore water, contained within the interstitial spaces of sediment, has been assumed to influx high concentrations of inorganic nutrients into surface waters during resuspension events. These short-term resuspension events rapidly introducing high concentration of nutrients into the water column. In order to determine the internal time scale of inorganic nitrogen cycling, a box-model nutrient budget, horizontal in situ transects, and vertical nutrient …
Improved Estimates Of Tributary Nitrogen Load To Casco Bay, Maine, Whitley J. Gray
Improved Estimates Of Tributary Nitrogen Load To Casco Bay, Maine, Whitley J. Gray
Electronic Theses and Dissertations
Over the past two decades, total nitrogen (TN) concentrations have increased in Casco Bay (CBEP 2015). The sources of the increased nitrogen are poorly understood but occur with simultaneous population growth and land use changes. The total riverine nitrogen load to Casco Bay was previously estimated by Liebman and Milstead (2012) using the United States Geologic Survey’s (USGS) SPAtially Referenced Regression On Watershed attributes (SPARROW) model. The SPARROW model uses watershed characteristics, regional monitoring data and nitrogen source data to estimate nitrogen loading but was not validated using measurements of nitrogen in the Casco Bay watershed. This study attempts to …
Dissolved Inorganic Nitrogen Dynamics In Swash Zone Sands Of Long Bay, Sc, Alexis F. Echols
Dissolved Inorganic Nitrogen Dynamics In Swash Zone Sands Of Long Bay, Sc, Alexis F. Echols
Honors Theses
A key component affecting the biogeochemistry of the sedimentary environment is pore water between grains of sediments. Sedimentary microorganisms are constantly modifying chemical compounds as part of their life functions which are then exchanged between the sediment column and the overlying water column. Dissolved inorganic nitrogen, a major element for life, takes on several forms including nitrate, nitrite, and ammonium which vary in concentration throughout the sediment and with respect to each other. The relative concentrations of these nitrogen species have been previously briefly explored in sandy columns, where redox gradients that control their relative concentrations can be fairly deep …
The Role Of Small Reservoirs In Reducing Reactive N Export Via Denitrification, Margaret Phillips, Wil Wollheim
The Role Of Small Reservoirs In Reducing Reactive N Export Via Denitrification, Margaret Phillips, Wil Wollheim
Honors Theses and Capstones
Reactive nitrogen (N), which harms ecosystem health, has been increasing in the biosphere, leading to higher N export to coastal ecosystems. Although man-made reservoirs can be significant sources of greenhouse gases, they can also retain N, thus reducing N export. Because many dams are relics from industrial hydropower, their removal is becoming increasingly common. It is therefore crucial to understand the ecological tradeoffs of man-made reservoirs. While previous studies have examined nutrient budgets and denitrification at inputs and outputs of large reservoirs, small reservoir dynamics remain understudied. In this study, we measured inputs and outputs of NO3 and N …