Spectroscopic Study Of Uranium (Vi) Reduction By Plant Biomass,
2013
SUNY Cortland
Spectroscopic Study Of Uranium (Vi) Reduction By Plant Biomass, Margaret C. Murphy, John Bargar, Noémie Janot
STAR Program Research Presentations
Uranium is a common and problematic groundwater contaminant at Department of Energy legacy sites. At the former uranium ore processing plant at Rifle, Colorado, sediments rich in decayed plant biomass contain large concentrations of uranium that are slowly being released back to the aquifer. To simulate the reaction that occurs in organic rich sediments of the Rifle aquifer, biomass was incubated in U (VI) bearing groundwater. Carbon X-ray absorption spectroscopy (XAS) was then used to measure if uranium was bound to the biomass. When uranium binds to biomass the peaks in the C XAS spectra will change shape. Uranium L …
The Use Of The Ostracode Cyprideis Americana (Sharpe) As A Proxy For Salinity In Bahamian Lake Systems,
2013
Western Kentucky University
The Use Of The Ostracode Cyprideis Americana (Sharpe) As A Proxy For Salinity In Bahamian Lake Systems, Rachel E. Bowles
Masters Theses & Specialist Projects
Ostracodes, bi-valved crustaceans, are potentially excellent proxies for salinity.They are abundant, react to changes in salinity, and secrete low-magnesium calcite shells that preserve information about their host water chemistry. Changes in valve trace element concentration, stable isotope composition, and sieve pore shape values have been linked to changes in salinity. This study analyzed the response of the euryhaline ostracode, Cyprideis americana, to salinity in six lakes from two Bahamian islands across two seasons. The purpose of this work was to determine which compositional and morphological variables in C. americana are the most useful for paleosalinity reconstructions.Ostracode and water samples were …
The Impact Of Nitrogen Contamination And River Modification On A Mississippi River Floodplain Lake,
2013
Southern Illinois University Edwardsville
The Impact Of Nitrogen Contamination And River Modification On A Mississippi River Floodplain Lake, Indu Karthic, Richard B. Brugam Ph.D., William A. Retzlaff, Kevin Johnson
SIUE Faculty Research, Scholarship, and Creative Activity
Anthropogenic nitrogen contamination has increased in ecosystems around the world (frequently termed the “nitrogen cascade”). Coke production for steel manufacturing is often overlooked as a source of nitrogen to natural ecosystems. We examined sediment cores from a Horseshoe Lake, a floodplain lake located just East of St. Louis Missouri (USA) to test whether a coking plant effluent could be traced using stable isotopes of nitrogen and diatom microfossils. The distribution of δ15N values in surface sediment samples from the lake shows the highest values near the coking plant effluent. Analysis stable isotopes of nitrogen from sediment cores using …
Will Hubbard Brook Soils Be A Source Or Sink Of Carbon In A Changing Climate?,
2013
Syracuse University
Will Hubbard Brook Soils Be A Source Or Sink Of Carbon In A Changing Climate?, Chris E. Johnson
Chris E Johnson
No abstract provided.
Will Hubbard Brook Soils Be A Source Or Sink Of Carbon In A Changing Climate?,
2013
cejohns@syr.edu
Will Hubbard Brook Soils Be A Source Or Sink Of Carbon In A Changing Climate?, Chris E. Johnson
Civil and Environmental Engineering
No abstract provided.
Microbial Biogeochemistry Of Boiling Springs Lake: A Physically Dynamic, Oligotrophic, Low-P H Geothermal Ecosystem,
2013
Humbolt State University
Microbial Biogeochemistry Of Boiling Springs Lake: A Physically Dynamic, Oligotrophic, Low-P H Geothermal Ecosystem, Patricia Lynne Siering, Gordon V. Wolfe, Mark S. Wilson, A. N. Yip, Cynthia M. Carey, Colin D. Wardman, Russell Scott Shapiro, Kenneth M. Stedman, Jennifer E. Kyle, Tong Yuan, Joy D. Van Nostrand, Zhili He, Jizhong Zhou
Biology Faculty Publications and Presentations
Boiling Springs Lake (BSL) in Lassen Volcanic National Park, California, is North America's largest hot spring, but little is known about the physical, chemical, and biological features of the system. Using a remotely operated vessel, we characterized the bathymetry and near-surface temperatures at sub-meter resolution. The majority of the 1.2 ha, pH 2.2 lake is 10 m deep and 50-52 [degrees]C, but temperatures reach 93 [degrees]C locally. We extracted DNA from water and sediments collected from warm (52 [degrees]C) and hot (73-83 [degrees]C) sites separated by 180 m. Gene clone libraries and functional gene microarray (GeoChip 3.0) were used to …
Lower Aptian Comparative Stratigraphy Of The Basco-Cantabrian Region (Spain) And Eastern Cordillera (Colombia): Implications For Local Factors In The Depositional Record Of Oceanic Anoxic Event 1a (Oae-1a),
2013
FIU, Earth and Environment Department
Lower Aptian Comparative Stratigraphy Of The Basco-Cantabrian Region (Spain) And Eastern Cordillera (Colombia): Implications For Local Factors In The Depositional Record Of Oceanic Anoxic Event 1a (Oae-1a), Tatiana Gaona Narvaez
FIU Electronic Theses and Dissertations
An important episode of carbon sequestration, Oceanic Anoxic Event 1a (OAE-1a), characterizes the Lower Aptian worldwide, and is mostly known from deeper-water settings. The present work of two Lower Aptian deposits, Madotz (N Spain) and Curití Quarry (Colombia), is a multiproxy study that includes fossil assemblages, microfacies, X-ray diffraction bulk and clay mineralogy, elemental analyses (major, minor, trace elements), Rock-Eval pyrolysis, biomarkers, inorganic and organic carbon content, and stable carbon isotopes. The results provide baseline evidence of the local and global controlling environmental factors influencing OAE-1a in shallow-water settings. The data also improve our general understanding of the conditions under …
Microbially Induced Magnesium Carbonation Reactions As A Strategy For Carbon Sequestration In Ultramafic Mine Tailings,
2013
The University of Western Ontario
Microbially Induced Magnesium Carbonation Reactions As A Strategy For Carbon Sequestration In Ultramafic Mine Tailings, Jenine Mccutcheon
Electronic Thesis and Dissertation Repository
The atmospheric carbon dioxide (CO2) concentration has increased due to anthropogenic fossil fuel combustion, causing higher global temperatures and other negative environmental effects. CO2 sequestration through carbonate mineralisation provides a stable, long term carbon sink. A natural hydromagnesite playa (Atlin, British Columbia, Canada) demonstrates the ability of phototrophic microorganisms to accelerate magnesium carbonate mineralisation. The site’s biogeochemistry was modeled in a 10 m flow-through bioreactor carbonation experiment, allowing for hydromagnesite precipitation conditions to be refined. Ultramafic mine tailings are a target substrate for carbonation reactions due to their high magnesium content. A synthetic mine leach water, designed …
The Biogeochemical Cycling Of Gold Under Surface And Near-Surface Environmental Conditions,
2013
The University of Western Ontario
The Biogeochemical Cycling Of Gold Under Surface And Near-Surface Environmental Conditions, Jeremiah P. Shuster
Electronic Thesis and Dissertation Repository
The mobility of gold at near-surface environmental conditions, e.g., supergene weathering environments, lateritic weathering systems, saline to hypersaline systems and placer gold environments, takes place as oxidised, soluble gold complexes and as reduced elemental gold. The transformation between aqueous and solid states of gold is attributed to the varying geochemical conditions that occur in dynamic environments that are catalysed in part by the biosphere. The primary focus of this research is the investigation of biogeochemical processes that contribute to the cycling of gold using laboratory models to represent various natural systems including chemolithotrophic bacteria, e.g., iron-oxidising bacteria, and heterotrophic sulphate-reducing …
Mechanisms Of Nutrient Limitation And Nutrient Acquisition In Managed And Unmanaged Forest Ecosystems,
2013
University of New Hampshire - Main Campus
Mechanisms Of Nutrient Limitation And Nutrient Acquisition In Managed And Unmanaged Forest Ecosystems, Matthew A. Vadeboncoeur
Doctoral Dissertations
Understanding the interactions between global change, human and natural disturbances, and other factors on biogeochemical processes in forests is necessary to ensure the sustainability of forest management. Here I report the results of several investigations into nutrient acquisition processes in the forests of New Hampshire. I begin with a meta-analysis of fertilization studies showing that phosphorus (P) and calcium (Ca) as well as nitrogen (N) may limit primary production in deciduous forests of the region. Because these limiting nutrients are all removed from the ecosystem when trees are harvested, I compared nutrient budgets under a range of harvesting scenarios with …
The Contribution Of Fe (Iii) And Humic Acid Reduction To Ecosystem Respiration In Drained Thaw Lake Basins Of The Arctic Coastal Plain,
2013
San Diego State University
The Contribution Of Fe (Iii) And Humic Acid Reduction To Ecosystem Respiration In Drained Thaw Lake Basins Of The Arctic Coastal Plain, David A. Lipson, Ted K. Raab, Dominic Goria, Jaime Zlamal
Ted K. Raab
Previous research showed that anaerobic respiration using iron (Fe) oxides as terminal electron acceptor contributed substantially to ecosystem respiration (ER) in a drained thaw lake basin (DTLB) on the Arctic coastal plain. As DTLB age, the surface organic layer thickens, progressively burying the Fe-rich mineral layers. We therefore hypothesized that Fe (III) availability and Fe reduction would decline with basin age. We studied four DTLB across an age gradient, comparing seasonal changes in the oxidation state of dissolved and extractable Fe pools and the estimated contribution of Fe reduction to ER. The organic layer thickness did not strictly increase with …
Hydro-Geochemical Coupling In Seawater Inundation Acid Sulfate Soils: Mobilisation Of Arsenic And Hysteresis In Iron And Sulfur Cycling,
2013
Southern Cross University
Hydro-Geochemical Coupling In Seawater Inundation Acid Sulfate Soils: Mobilisation Of Arsenic And Hysteresis In Iron And Sulfur Cycling, Scott Johnston, Annabelle Keene, Edward Burton, Richard Bush, Leigh Sullivan
Associate Professor Edward D Burton
A large-scale field trial indicates that tidal seawater inundation of coastal acid sulfate soils (CASS) stimulates iron and sulfate reducing conditions, leading to the generation of internal alkalinity and greatly decreasing soil / groundwater acidity. This remediation technique can be considered highly effective from the relatively narrow perspective of decreasing acidity and raising pH. However, a broader perspective reveals that tidal seawater inundation initiates complex and tightly coupled hydrological and geochemical processes within sediments and porewaters. These processes have had a profound effect on the mobilisation, redistribution and transformation of Fe minerals in the landscape (Johnston et al., 2011a) – …
Using Hydrologic Measurements To Investigate Free Phase Gas In A Maine Peatland, Usa,
2013
The University of Maine
Using Hydrologic Measurements To Investigate Free Phase Gas In A Maine Peatland, Usa, Christiaan Bon
Electronic Theses and Dissertations
Northern Peatlands cover more than 350 million ha (~3 percent of Earth’s surface) and are an important source of methane (CH4) and other biogenic gases contributing to climate change. Free phase gas (FPG) accumulation and episodic release has recently been recognized as an important mechanism for biogenic gas flux from peatlands. It is likely that gas production and groundwater flow are interconnected in peatlands: groundwater flow influences gas production by regulating geochemical conditions and nutrient supply available for methanogenesis while FPG influences groundwater flow through a reduction in peat permeability and by creating excess pore fluid pressures. Water samples collected …
Exploring Greenhouse Gas Emissions From Beaver Ponds In Southern Rhode Island,
2013
Department of Natural Resources Science, University of Rhode Island
Exploring Greenhouse Gas Emissions From Beaver Ponds In Southern Rhode Island, Molly K. Welsh
Senior Honors Projects
Climate change is one of the largest environmental issues facing humanity today, having the potential to alter fresh water availability, agricultural yields, forest productivity, and global sea levels. As climate change is likely to increase the intensity of extreme weather events, the potential for massive human and financial consequences is of further concern. The Intergovernmental Panel on Climate Change asserts that climate change is due to anthropogenic alterations of the atmosphere’s composition, with additional contributions from natural biochemical processes. In particular, the rapid increase in the concentrations of greenhouse gases (GHGs) in the atmosphere can trigger atmospheric warming as these …
Springtime Contribution Of Dinitrogen Fixation To Primary Production Across The Mediterranean Sea,
2013
Old Dominion University
Springtime Contribution Of Dinitrogen Fixation To Primary Production Across The Mediterranean Sea, E. Rahav, B. Herut, A. Levi, Margaret Mulholland, I. Berman-Frank
OES Faculty Publications
Dinitrogen (N-2) fixation rates were measured during early spring across the different provinces of Mediterranean Sea surface waters. N-2 fixation rates, measured using N-15(2) enriched seawater, were lowest in the eastern basin and increased westward with a maximum at the Strait of Gibraltar (0.10 to 2.35 nmol NL-1 d(-1), respectively). These rates were 3-7 fold higher than N-2 fixation rates measured previously in the Mediterranean Sea during summertime and we estimated that methodological differences alone did not account for the seasonal changes we observed. Higher contribution of N-2 fixation to primary production (4-8 %) was measured in the western basin …
The Effects Of Physicochemical Properties Of Ceo2 Nanoparticles On Toxicity To Soil Denitrification Processes,
2013
Clemson University
The Effects Of Physicochemical Properties Of Ceo2 Nanoparticles On Toxicity To Soil Denitrification Processes, Jessica Dahle
All Theses
Due to the rise of nanotechnology in industry, the concentrations of engineered metal oxide nanoparticles being released to the environment are increasing daily. Cerium-based compounds such as nanoparticulate ceria (NP CeO2) have received much attention in the last several years due to their popular applications (e.g., mischmetal, pharmaceuticals, nanotechnology) in industrial and commercial uses. Like many emerging pollutants, NP CeO2 is often released to the environment, where its toxicological effects are not well known. Though several environmental exposure pathways have been identified for CeO2 NPs, a major route of NP introduction to the environment is via biosolids application to agricultural …
Litter Conditioning Is Differentially Affected By Leaf Species, Phosphorus Enrichment, And Light Availability,
2013
University of Arkansas, Fayetteville
Litter Conditioning Is Differentially Affected By Leaf Species, Phosphorus Enrichment, And Light Availability, Erin E. Scott
Graduate Theses and Dissertations
Anthropogenic enrichment of nitrogen and phosphorus is one of the most pervasive and detrimental threats to aquatic ecosystems worldwide. In streams that rely on allochthonous basal food resources, such as leaves, nutrient pollution can result in altered food quality and decreased carbon (C) standing stocks. However, the magnitude and mechanisms of this change in quality are poorly understood. Laboratory microcosm studies were conducted to 1) quantify the response of litter C:P to a gradient of phosphorus (P) enrichment (0, 0.05, and 0.5 mg SRP/L) across leaf species with variable levels of degradability (sugar maple and oak), and 2) quantify the …
Arsenic Mobilization And Iron Transformations During Sulfidization Of As(V)-Bearing Jarosite,
2013
Southern Cross University
Arsenic Mobilization And Iron Transformations During Sulfidization Of As(V)-Bearing Jarosite, Scott Johnston, Edward Burton, Annabelle Keene, Britta Planer-Friedrich, Andreas Voegelin, Mark Blackford, Greg Lumpkin
Associate Professor Edward D Burton
Jarosite (KFe3(SO4) 2(OH)6) is an important host-phase for As in acid mine drainage (AMD) environments and coastal acid sulfate soils (CASS). In AMD and CASS wetlands, jarosite may encounter S(−II) produced by sulfate reducing bacteria. Here, we examine abiotic sulfidization of As(V)-bearing K-jarosite at pH 4.0, 5.0, 6.5 and 8.0. We quantify the mobilization and speciation of As and identify corresponding Fe mineral transformations. Sulfide-promoted dissolution of jarosite caused release of co-precipitated As and the majority of mobilized As was re-partitioned to a readily exchangeable surface complex (AsEx). In general, maximum As mobilization occurred in the highly sulfidized end-members of …
Recovery From Disturbance Requires Resynchronization Of Ecosystem Nutrient Cycles,
2013
Marine Biological Lab
Recovery From Disturbance Requires Resynchronization Of Ecosystem Nutrient Cycles, Edward B. Rastetter, Ruth D. Yanai, R Quinn Thomas, Matthew A. Vadeboncoeur, Timothy J. Fahey, Melany C. Fisk, Bonnie L. Kwiatkowski, Steven P. Hamburg
Earth Systems Research Center
Nitrogen (N) and phosphorus (P) are tightly cycled in most terrestrial ecosystems, with plant uptake more than 10 times higher than the rate of supply from deposition and weathering. This near-total dependence on recycled nutrients and the stoichiometric constraints on resource use by plants and microbes mean that the two cycles have to be synchronized such that the ratio of N:P in plant uptake, litterfall, and net mineralization are nearly the same. Disturbance can disrupt this synchronization if there is a disproportionate loss of one nutrient relative to the other. We model the resynchronization of N and P cycles following …
Cycling Of Molecular Hydrogen In Subarctic Sweden,
2013
University of New Hampshire - Main Campus
Cycling Of Molecular Hydrogen In Subarctic Sweden, Victoria Ward
Honors Theses and Capstones
No abstract provided.
