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Articles 1 - 9 of 9
Full-Text Articles in Physical Sciences and Mathematics
Nutrient Dynamics Of Freshwater Estuarine Sediments Disturbed By Dredging, Ryan Allan John Roekle
Nutrient Dynamics Of Freshwater Estuarine Sediments Disturbed By Dredging, Ryan Allan John Roekle
Theses and Dissertations
This study examined the nutrient environment of sediments in the Milwaukee River estuary and the dynamics of those nutrients during simulated disturbance experiments within the context of large-scale dredging remediation. Surface sediments were collected from throughout the Milwaukee estuary (including river, harbor, and nearshore stations) by PONAR, centrifuged to separate porewater (interstitial water) from solid material, and filtered to further isolate and stabilize dissolved material. Porewaters were analyzed for dissolved nutrients including ammoniacal nitrogen (AN), nitrate, nitrite, and soluble reactive phosphorus (SRP). Surface sediment porewaters within the estuary were often highly enriched in AN and SRP, which were often 10-2000x …
Arctic Ocean And Subarctic Seas Dynamics In A Changing Climate, Sarah B. Hall
Arctic Ocean And Subarctic Seas Dynamics In A Changing Climate, Sarah B. Hall
Theses and Dissertations
Salinity is the primary determinant of the Arctic Ocean’s vertical density stratification in the upper ocean, which has major implications on the ocean’s physical dynamics alongside a period of rapidly declining sea ice. In recent decades, the Arctic’s freshwater content (FWC) has increased as a result of the accumulation of freshwater source inputs. Additional freshwater exported to the North Atlantic may hinder overturning processes that are vital to the regulation of global climate. This dissertation employs in situ measurements, satellite observations, and ocean model simulations to better understand salinity and freshwater changes in the Arctic Ocean during this changing climate. …
Influence Of Nutrients And The Native On E. Coli Survival In The Beach Environment, Brigid Meyers
Influence Of Nutrients And The Native On E. Coli Survival In The Beach Environment, Brigid Meyers
Theses and Dissertations
E. coli is used as an indicator for water quality to determine if water poses a health risk for pathogens. Past research has shown that E. coli is present in high numbers in freshwater beach sands distinct from fecal pollution events, yet the precise mechanism for their persistence in not well understood. Persistent E. coli populations in sand can resuspend into adjacent water and lead to increased beach closures when no threat is present. This work identifies factors that influence the survival of E. coli in sand using laboratory microcosms to replicate beach conditions. Microcosms were deployed to examine the …
The Flow Less Traveled: Documenting Independent Original Research On Fluid Flow Interactions In The Laurentian Great Lakes And Immediate Surroundings, Thomas F. Hansen
The Flow Less Traveled: Documenting Independent Original Research On Fluid Flow Interactions In The Laurentian Great Lakes And Immediate Surroundings, Thomas F. Hansen
Theses and Dissertations
This work is a compilation of several research projects undertaken by the author. Each research effort identifies a problem that has been addressed traditionally using methods that are significantly costly, to such an extent that, in general, funding, convenience, and practicality are primary limiting factors to their effective implementation. In each case, the author has been able to either build upon existing, less expensive alternatives, or even invent novel approaches. The fundamental recurring research question is, can creative, even novel, computational approaches make more efficient use of resources to interpret or present data in such a way as to make …
Seasonal And Spatial Variations In Chemical Composition And Fluxes Of Dissolved Organic Matter And Nutrients In The Lower Milwaukee River, Tarek A. Teber
Seasonal And Spatial Variations In Chemical Composition And Fluxes Of Dissolved Organic Matter And Nutrients In The Lower Milwaukee River, Tarek A. Teber
Theses and Dissertations
Physical, chemical and biological processes directly influence the transport, composition, and fluxes of dissolved organic matter (DOM) in river watersheds. Changes in the abundance and composition of DOM and nutrients (P&N) in the watershed should reflect changes in hydrological cycle, effluent discharge, land-use and land-cover, and anthropogenic activities in the river basin, especially in rivers that run through metropolitan areas such as the Milwaukee River. Despite the importance of DOM to ecosystem health and function, a literature search to date finds no comprehensive accounting of DOM in the Milwaukee River. To examine DOM dynamics, monthly water samples were collected between …
Tap Versus Bottle: A Mixed Methods Analysis Of Public Water Supply And The Bottled Water Industry In The United States, Catherine Simons
Tap Versus Bottle: A Mixed Methods Analysis Of Public Water Supply And The Bottled Water Industry In The United States, Catherine Simons
Theses and Dissertations
Discrepancies exist between the regulation of public tap water by the EPA and bottled water by the FDA. The Safe Drinking Water Act mandates the EPA to set national contaminant standards for drinking water as well as regulations to ensure source water protection, treatment, monitoring, compliance, enforcement, waste water, and public access to water quality information. Bottled water is subject to a differing mandate. As a food product regulated by the FDA, bottled water is required to comply with FDA food regulations as well as specific bottled water regulation regarding standards of identity, quality and cGMP. As a result of …
Freshwater Phytoplankton Populations Detected Using High Pressure Liquid Chromatography (Hplc) Of Taxon-Specific Pigments, Lauren Jeanne Simmons
Freshwater Phytoplankton Populations Detected Using High Pressure Liquid Chromatography (Hplc) Of Taxon-Specific Pigments, Lauren Jeanne Simmons
Theses and Dissertations
Phytoplankton are key primary producers in aquatic ecosystems, and the principle food source for primary consumers. Individual phytoplankton species respond to different physical, chemical and biological parameters, so monitoring taxonomic composition of the phytoplankton community is a means to monitor changes in environmental conditions. Phytoplankton community changes have frequently been monitored by estimating biomass (using chlorophyll a, measured fluorometrically), and taxonomic data obtained from cell counts. While such methods are useful, they are time-consuming. I hypothesized that high pressure liquid chromatography (HPLC) methods, which have been frequently used in marine systems, would allow separation and identification of key pigments. …
A Water Quality Investigation Of Kimages Creek, Michael Trop
A Water Quality Investigation Of Kimages Creek, Michael Trop
Theses and Dissertations
Analysis of continuous monitoring water quality data (temperature, specific conductivity, depth, pH, dissolved oxygen, and turbidity) at two locations in a tidal freshwater creek (Kimages Creek) characterized seasonal variation and responses to short-term events. Supplemental water quality measurements were collected to describe longitudinal variations in the creek. There were significant differences in water quality between the two continuous monitoring stations (one tidal and unforested, the other non-tidal and forested) over varying time scales. Rain events showed increases in turbidity, depth and dissolved oxygen, and reductions in temperature, conductivity, and pH at both stations. Tides influenced the water quality at the …
The Responses Of Blue Crabs (Callinectes Sapidus) To Hypoxia/Hypercapnia In Freshwater, James Martin
The Responses Of Blue Crabs (Callinectes Sapidus) To Hypoxia/Hypercapnia In Freshwater, James Martin
Theses and Dissertations
The present research examined respiratory responses of blue crabs to long term (4, 13, and 21 days) hypercapnic hypoxia in freshwater at 23 C. Hypoxic conditions (50-60 & 75-85 mmHg O2) were induced by allowing the crabs to consume their oxygen supply, resulting in a hypercapnic induced decrease in pH that remained through the exposure. Postbranchial hemolymph responses to hypoxia/hypercapnia in freshwater demonstrate decreases in PO2, increases in PCO2, and decreases in pH. Lactate levels decreased over time, but hemocyanin concentration was highly variable with no trends. PH, lactate, and hemocyanin observations also demonstrated high variability and a variety of …