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Full-Text Articles in Physical Sciences and Mathematics
Sediment And Organic Carbon Burial In Englebright Lake, Ca Over The Last Century, Christina Rose Pondell
Sediment And Organic Carbon Burial In Englebright Lake, Ca Over The Last Century, Christina Rose Pondell
Dissertations, Theses, and Masters Projects
The proliferation of dams has impacted over 67% of the world's largest rivers, degrading ecosystems, severing river-watershed connectivity, and reducing water, sediment, and carbon supply from rivers to the coastal ocean by 20 to 100%. Many studies have focused on the downstream impacts of dams, but few have quantified the amounts and quality of organic matter stored within impoundments. This study examined organic carbon (OC) sources and accumulation in a reservoir in northern California to characterize the organic matter retained in terrestrial systems by these man-made structures and relate the amounts and quality of OC to mining, damming and flood …
Poverty Shelf, New Zealand From The Holocene To Present: Stratigraphic Development And Event Layer Preservation In Response To Sediment Supply, Tectonics And Climate, Lila Eve Rose Pierce
Poverty Shelf, New Zealand From The Holocene To Present: Stratigraphic Development And Event Layer Preservation In Response To Sediment Supply, Tectonics And Climate, Lila Eve Rose Pierce
Dissertations, Theses, and Masters Projects
The small, high sediment yield Waipaoa River is located on the tectonically active, mountainous Poverty Margin on the east coast of the North Island, New Zealand. In contrast to sedimentary sequences on passive margin shelves, active margins, such as the Poverty Margin, can preserve continuous records of changing geological and environmental conditions at the land-sea interface during rapid sea-level rise. Two subsiding mid-shelf basins on the Poverty Shelf contain thick transgressive sequences which provide a record of evolving river, climate, landscape, and oceanographic conditions since the Last Glacial Maximum (LGM). This dissertation investigates the stratigraphic development of Poverty Shelf, including …
Planar Oxides As A Novel Approach To Metal Ion Sorption Studies: From The Lab To The Field, Christine F. Conrad
Planar Oxides As A Novel Approach To Metal Ion Sorption Studies: From The Lab To The Field, Christine F. Conrad
Dissertations, Theses, and Masters Projects
The purpose of this work is to investigate the use of planar oxides as tools for metal ion sorption studies that can be used in both laboratory and field settings. to do this, a three-step approach was used. In the first step, the reactivities of the planar gamma-Al2O3 surfaces relative to pure phase gamma alumina was investigated through Pb(II) sorption studies. The relative quantitative uptake of Pb(II) on the planar gamma alumina was found to be comparable to that on the bulk. XAS analysis showed that the coordination geometry and local binding environment of the Pb(II) complexes were similar on …
Polycyclic Aromatic Hydrocarbon Sources And Distribution In An Urban Estuary, Shelby E. Walker
Polycyclic Aromatic Hydrocarbon Sources And Distribution In An Urban Estuary, Shelby E. Walker
Dissertations, Theses, and Masters Projects
As part of the assessment of the potential risk posed by contaminated sediments to the environment and human health, the United States Environmental Protection Agency (USEPA) is developing a set of sediment quality criteria (SQC) that are based on equilibrium partitioning (EqP). While EqP theory has often been used to predict contaminant concentrations within a factor of two for a range of sediment types, substantial deviations from predicted values have also been documented. The objective of this research was to evaluate the influence of PAH source on PAH sediment-pore water partitioning and distribution in sediments. The Elizabeth River is one …
Laboratory Oxide Coatings: Physical Form And Surface Chemistry, Kea U. Duckenfield
Laboratory Oxide Coatings: Physical Form And Surface Chemistry, Kea U. Duckenfield
Dissertations, Theses, and Masters Projects
The impact of dissolved trace metals on aquatic ecosystems and human health is controlled by sorption, i.e., binding to the surfaces of environmental particles. Since many environmental particles are coated with highly reactive substances, and since discrepancies in trace metal sorption behavior persist between oxides developed in the laboratory and environmental oxide phases, it was hypothesized that the physical form of oxide coatings may influence the chemical properties of the coated particle. Therefore, relationships between the physical forms of several different Fe(III) oxide coatings and the Cu(II) sorption behavior of the coated solids were investigated in comparison with the component …
Geochemistry Of Small Mountainous Rivers Of Papua New Guinea: Local Observations And Global Implications, Megan B. Raymond
Geochemistry Of Small Mountainous Rivers Of Papua New Guinea: Local Observations And Global Implications, Megan B. Raymond
Dissertations, Theses, and Masters Projects
Small, wet mountainous rivers (runoff > 0.63 m yr" 1 , headwater elevation> 1000 m, basin area < 10,000 km2 ) contribute a disproportionate amount of sediment to the global ocean due to their steep high topography, erosive substrate, and often high precipitation. Scattered data have suggested a slight, but statistically insignificant, inverse relationship between total dissolved solid (TDS) yield (T km-2 yr-1 ) and basin area, but small to very small rivers (basin areas< 10,000 km2 ) have been poorly documented. To fill this data gap, as well as to elucidate possible links between weathering and basin hydrology, nine small wet mountainous rivers, basin areas 22 km2-2300 km2 , were sampled in late May 1997 in northeastern Papua New Guinea. TDS concentrations ranged from 75 to 148 mg L-1 , with no correlation to watershed area. The dissolved organic carbon (DOC) and particulate organic carbon (POC) values were low, with a mean DOC value of 135 f.Lmol L-1 ; POC values were lower, averaging 3lf.Lmol L- 1 • TDS data, combined with large wet mountainous river TDS data, demonstrate a significant inverse relationship between TDS yield and basin area. As a result, small wet mountainous rivers contribute a disproportionate amount of TDS, and have the highest TDS yields of any class of river. This observation is attributed to the high runoff of the sampled rivers (-2m yr-1 ), in addition to high rates of chemical weathering, which is facilitated by the erosive substrate and high rates of organic matter remineralization.
Polycyclic Aromatic Hydrocarbon (Pah) Distributions Within Urban Estuarine Sediments, Siddhartha Mitra
Polycyclic Aromatic Hydrocarbon (Pah) Distributions Within Urban Estuarine Sediments, Siddhartha Mitra
Dissertations, Theses, and Masters Projects
Sediments and pore waters from two urban estuaries ranging in sediment mixing energy were studied to evaluate the potential release of contaminants from particles during sediment diagenesis. Two sites in Elizabeth River, VA and two tributaries in the Hudson River Watershed were sampled for polycyclic aromatic hydrocarbons (PAHs). Sediment age, total sediment organic carbon (TOC), carbon to nitrogen (C/N) ratios, and particle surface area (SA) were also sampled at these sites. In the Elizabeth River, both sites sampled (Site 1 and Site 2) have been non-depositional for the past 70 y or are comprised of old dredge spoil. PAH K&\sp\prime\sb{lcub}\rm …
Studies On Processes Controlling The Input Of Agricultural Chemicals In Groundwater To Surface Waters, Edward Laurence Libelo
Studies On Processes Controlling The Input Of Agricultural Chemicals In Groundwater To Surface Waters, Edward Laurence Libelo
Dissertations, Theses, and Masters Projects
This dissertation describes several studies of groundwater quality, the fate and transport of nutrients and atrazine in groundwater systems and physical processes at the sediment-water interface which impact on groundwater discharge. Groundwater monitoring wells were installed at the Goodwins Island and Catlett Island NERRS sites in Virginia and agricultural, suburban and forest land use sites in the York and James River Basins. Groundwater was analyzed for nutrients, pH, salinity and trace organics. Shoreline land use, associated nutrient loading and an estimate of total groundwater flux suggest that groundwater contributes up to 30% of the total nitrogen input to the Chesapeake …
Effect Of Water Column Ph And No3 On Ortho-Phosphate Release Rates From Freshwater Sediments, Beverly Eloise Baker
Effect Of Water Column Ph And No3 On Ortho-Phosphate Release Rates From Freshwater Sediments, Beverly Eloise Baker
Dissertations, Theses, and Masters Projects
No abstract provided.
Sorption Of Nonpolar Organics On Minerals And Aquifer Materials, Thomas B. Stauffer
Sorption Of Nonpolar Organics On Minerals And Aquifer Materials, Thomas B. Stauffer
Dissertations, Theses, and Masters Projects
The sorption of nonpolar organic chemicals on hydrous oxides, clay minerals, and subsurface aquifer materials was studied using the batch isotherm technique. Radiolabeled (&\sp{lcub}14{rcub}&C) trichloroethylene, orthodichlorobenzene, naphthalene, and 1-methylnaphthalene were sorbed on mineral sorbents, subsurface aquifer materials, and a surface soil at six different equilibrium concentrations over a concentration range from 0.001 mg/L to 1.0 mg/L. A knowledge of the sorption coefficients of these fuel components and solvents is necessary to predict the transport of these chemicals through groundwater systems and ultimately to rivers, lakes, and estuaries. Sorption on oxides and surface soils was found to be pH-dependent with decreased …
Thermodynamics And Kinetics Of Aqueous Solution Of Liquid Hydrocarbon Mixtures (Solutes, Petroleum), David Robert. Burris
Thermodynamics And Kinetics Of Aqueous Solution Of Liquid Hydrocarbon Mixtures (Solutes, Petroleum), David Robert. Burris
Dissertations, Theses, and Masters Projects
Two-phase systems of a liquid hydrocarbon mixture, containing medium molecular weight (C(,7)-C(,12)) aromatic and aliphatic hydrocarbons, and water were examined in both equilibrium and kinetic experiments. Knowledge of the aqueous solution behavior of liquid hydrocarbon mixtures is of importance in determining the fate of hydrocarbon components in such systems of an environmental or geologic nature. Solute concentrations were determined by solvent extraction followed by gas chromatography. The equilibrium solute concentration for a given component i (C(,i)) is related to the pure compound solubility (C(,i)('o)), mole fraction of component i in the hydrocarbon phase (x(,i(h))) and the activity coefficient of component …
On The Occurrence And Origins Of Hopanoids In The Chesapeake Bay (Maryland, Virginia), Gullaya Wattayakorn
On The Occurrence And Origins Of Hopanoids In The Chesapeake Bay (Maryland, Virginia), Gullaya Wattayakorn
Dissertations, Theses, and Masters Projects
Analyses of surface sediment samples from the Chesapeake Bay and sediment cores from the James and the Potomac River showed that pentacyclic triterpenoids of the hopanoid skeleton were ubiquitously present in all samples. The hopanoids have been identified and quantified by gas chromatographic retention data obtained on SE-52 stationary phase, and mass spectral comparisons with the branched/cyclic fraction of a Lorraine coal extract as well as published data from authentic standards. Hopanoid acids are of extended 17(beta)(H), 21(beta)(H)-structure, ranging from C(,31) to C(,33). The 17(beta)(H), 21(beta)(H)-bishomohopanoic acid (C(,32)) is always the major acid found in the samples. All acids were …
Organic Compound Levels In A Sediment Core From The Elizabeth River Of Virginia, Muzhen Lu
Organic Compound Levels In A Sediment Core From The Elizabeth River Of Virginia, Muzhen Lu
Dissertations, Theses, and Masters Projects
No abstract provided.
Chemistry Of Chesapeake Bay Sediments, David Kenneth Young
Chemistry Of Chesapeake Bay Sediments, David Kenneth Young
Dissertations, Theses, and Masters Projects
No abstract provided.