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Sediment

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Full-Text Articles in Earth Sciences

Controls On Sediment Connectivity In Fluvial Networks Impacted By Wildfire Across Utah, Alec Arditti Dec 2023

Controls On Sediment Connectivity In Fluvial Networks Impacted By Wildfire Across Utah, Alec Arditti

All Graduate Theses and Dissertations, Fall 2023 to Present

Flooding and sedimentation caused by wildfire are among the greatest threats to watersheds, fish populations and reservoirs in the western US. Burned landscapes are at risk for increased runoff and erosion and have the potential to transport sediment that may put downstream resources at risk. The ability of the channel to transport sediment downstream, known as the connectivity, is important for determining where impacts may occur. Sediment bottlenecks are locations within the watershed where local conditions produce a persistent decrease in downstream connectivity of sediment, resulting in increased sediment deposition and potentially a substantial modification of the local channel and …


Sedimentary Processes And Instability On The Mississippi River Delta Front Near The Wreck Of The Ss Virginia, Nathan Figueredo Jun 2023

Sedimentary Processes And Instability On The Mississippi River Delta Front Near The Wreck Of The Ss Virginia, Nathan Figueredo

LSU Doctoral Dissertations

Multi-cores and piston cores were collected seaward of the Mississippi River Delta’s Southwest Pass at ~80 m water depth in 2017 to better understand sedimentary characteristics and processes on the Mississippi River Delta Front (MRDF) in the vicinity of the SS Virginia shipwreck, and to support marine archeological research. Core analyses were performed to inform our understanding of the dynamics of sediment motion in the study area through radionuclide activity (210Pb and 137Cs), volume frequency of grain size, bulk density, and fabric (X-Radiography). Sediment accumulation rates (SAR), calculated from multi-core 210Pb activity are 0.22 - 0.29 …


Geomorphology Of Tidal Wetlands: Impacts Of Extreme And Annual Flood Events To Salt Marsh And Mangrove Systems, Frances R. Griswold Apr 2023

Geomorphology Of Tidal Wetlands: Impacts Of Extreme And Annual Flood Events To Salt Marsh And Mangrove Systems, Frances R. Griswold

Doctoral Dissertations

Tidal wetlands are vital for buffering coastal settings from the threats of accelerated sea level rise and storms. Understanding the factors that are most influential for the maintenance and recovery of tidal wetlands after extreme events compounded by future accelerated sea level rise is of the utmost importance, yet this knowledge is not well established. Two tidal wetland schemas investigated in this dissertation are mangrove systems in Vieques, Puerto Rico (including robust lagoonal-mangrove forest systems and fringing mangrove forests), and salt marshes in New England. While the climatic forcings, vegetation type, and locations are vastly different for these two tidal …


Assessing Ecosystem Health Through Contaminants In The Tijuana River National Estuarine Research Reserve, Nancy Torres Jan 2023

Assessing Ecosystem Health Through Contaminants In The Tijuana River National Estuarine Research Reserve, Nancy Torres

Theses

Although the Tijuana River Estuary (TRE) remains the largest, most-intact coastal wetland in Southern California, it has a history of major changes, much of this related to its location immediately north of the US / Mexico Border. One of the primary challenges is cross-border flows from the rapidly growing city of Tijuana, Baja California, Mexico, and the delivery of wastewater, debris, and sediment to sensitive coastal wetland ecosystems. There is a need to more fully investigate these environmental changes to assess the ecosystem health of the Tijuana River Estuary over time, especially related to pollution impacts. This can inform an …


Assessing Ecotoxicity Of Surface Water And Sediment In The Little Scioto River, Leah Suzanne Morgan Jan 2023

Assessing Ecotoxicity Of Surface Water And Sediment In The Little Scioto River, Leah Suzanne Morgan

Theses, Dissertations and Capstones

Aquatic toxicology evaluates the impact of pollution on freshwater and marine biota. Polycyclic aromatic hydrocarbons (PAHs) are one class of chemicals prevalent in the environment that impair aquatic organisms. This study examined the effect of contaminated surface water and sediments from a former wood treatment facility on four aquatic species: Pimephales promelas (fathead minnow), Ceriodaphnia dubia (water flea), Chironomus dilutus (midge), and Daphnia magna (water flea). The findings showed that sediment contamination had no significant effect on survival and growth of C. dilutus or on survival of D. magna. Surface water contamination began to have a significant effect on …


Using Camera-Monitored Sediment Traps To Evaluate Sediment Availability And The Role Of Waves In Resuspending Seafloor Sediment, Bellingham Bay, Wa, Liam Horner Jan 2023

Using Camera-Monitored Sediment Traps To Evaluate Sediment Availability And The Role Of Waves In Resuspending Seafloor Sediment, Bellingham Bay, Wa, Liam Horner

WWU Graduate School Collection

Understanding nearshore sediment budgets and processes is important for evaluating coastal hazards, habitats, and contaminant fate to enable informed decisions in coastal planning and management. I aimed to evaluate the role of waves in resuspending and redistributing sediments and by proxy contaminants in the urban/estuarine Bellingham Bay, and better understand the transport and rate of fluvial sediment moving through the nearshore. I integrated analyses using camera-mounted sediment traps, seafloor grain-size data, short-lived radioisotopes, and other fluvial, physical oceanographic, and wind data. I paired cameras with sediment traps, to identify the timing and rate of sedimentation on the seafloor at hourly …


Reactive Iron Mineral Coatings In Redox Transition Zones Of A Site With Historical Contamination: Abiotic Attenuation, Xin Yin May 2022

Reactive Iron Mineral Coatings In Redox Transition Zones Of A Site With Historical Contamination: Abiotic Attenuation, Xin Yin

Dissertations

Reactive iron mineral coatings are found throughout reduction-oxidation (redox) transition zones and play a significant role in contaminant transformation processes. In this study, an 18.3-meter core is collected, subsampled, and preserved under anoxic conditions to maintain its original redox state. Screening analyses are conducted at sampling increments of 5.08 cm in depth for the following: elemental concentrations with X-ray fluorescence (XRF), sediment pH, sediment oxidation-reduction potential (ORP), total volatile organic carbon (TVOC) in the sample headspace, and abundant bacteria (16S rRNA sequencing). Using the Fe and S gradients correlated with microbial data, five RTZs are delineated. To characterize iron mineral …


Late Quaternary Glacier Fluctuations At Picayune Lake, Northern California, Aidan Patrick Cowan Jan 2022

Late Quaternary Glacier Fluctuations At Picayune Lake, Northern California, Aidan Patrick Cowan

Cal Poly Humboldt theses and projects

The Klamath Mountains are a 233-km-long (north to south) mountain range located in northern California that shows extensive geomorphic evidence of Pleistocene glaciation. Within the Klamath’s there are many highland lakes, which record evidence of glacial deposition, one of which is Picayune Lake. Lake sediment data collected from Picayune Lake offers insights into the glaciation, and broader depositional history of the Picayune Lake Valley, as well as the climate history of the Klamath Mountains region. I measured magnetic susceptibility, loss on ignition, and grain size in sediment cores and used radiocarbon dating to determine a chronology of glacier fluctuations in …


Chemical Characterization Of Clastic Cave Sediments And Insights Into Particle Transport And Storage In Karst Aquifers, Jill L. Riddell Jan 2022

Chemical Characterization Of Clastic Cave Sediments And Insights Into Particle Transport And Storage In Karst Aquifers, Jill L. Riddell

Graduate Theses, Dissertations, and Problem Reports

Abstract

Chemical characterization of clastic cave sediments and insights into particle transport and storage in karst aquifers

Jill L. Riddell

Cave sediments can be divided into two groups: precipitates and clastics. Precipitates are speleothems, or lithologic or mineral features that are chemically precipitated in the cave environment. Clastic cave sediments are frequently described by depositional facies, sorting, and particle size (Bosch and White, 2004). Robust analytical chemical analyses of these sediments to quantify their physical and chemical components is rarely performed although some chemical characterization of mineralogy and paleomagnetism has become prevalent in recent years (Chess et al., 2010; Sasowsky …


Advances In Assessing Flood Hazard And Sediment Dynamics At The Coast, Hannah Baranes Oct 2021

Advances In Assessing Flood Hazard And Sediment Dynamics At The Coast, Hannah Baranes

Doctoral Dissertations

Earth’s coastlines are shaped by geophysical and human dynamism. Waves, tides, currents, and sea level change reconfigure coastal environments on hourly to centennial timescales, and the coast is experiencing the fastest economic and population growth rates in the world. This coexistence of a dynamic environment and human development makes coastal communities uniquely vulnerable to natural hazards. Climate change is expected to exacerbate flooding and erosion hazards in the future; thus, it is critical that we understand the underlying physical drivers of coastal change. The overarching goal of this dissertation is to improve the mechanistic understanding and quantification of dynamic processes …


Evidence For Middle Miocene Elevated Topography Isolating The Southern Klamath Mountains Province: A U-Pb & Lu-Hf Detrital Zircon Study Of The Weaverville Formation, Dana J. Christensen Jan 2021

Evidence For Middle Miocene Elevated Topography Isolating The Southern Klamath Mountains Province: A U-Pb & Lu-Hf Detrital Zircon Study Of The Weaverville Formation, Dana J. Christensen

Cal Poly Humboldt theses and projects

The Klamath Mountains Province (KMP) records a robust history of active North American margin tectonics and crustal growth through the subduction-accretion of oceanic and island-arc terranes spanning Devonian through Cretaceous time. However, preservation of Cenozoic rocks is minimal, rendering the geologic record, topography, and tectonics during this timeframe difficult to reconstruct. The only Miocene terrestrial sedimentary unit that exists in the KMP is the fluvially deposited Tertiary Weaverville Formation (Tw) that is preserved in five fault-bounded basins in the southern part of the province. This study presents new uranium-lead (U-Pb) age data and epsilon hafnium (εHf) isotopic ratios from detrital …


Grain-Size And Permeability Of Sediments Within The Hyporheic Zone At The Theis Environmental Monitoring And Modeling Site, Great Miami River And Buried Valley Aquifer, Southwest Ohio, Usa, Timothy Wayne Cornett Jan 2021

Grain-Size And Permeability Of Sediments Within The Hyporheic Zone At The Theis Environmental Monitoring And Modeling Site, Great Miami River And Buried Valley Aquifer, Southwest Ohio, Usa, Timothy Wayne Cornett

Browse all Theses and Dissertations

The Theis Environmental Monitoring and Modeling Site is a field research facility, located on the Great Miami River in southwest Ohio, dedicated to the study of hyporheic zone processes. The site is underlain by an aquifer on the order of 21 meters thick, comprised of fluvial deposits. The permeability of the aquifer sediments was quantified both from one large scale hydraulic test (~100 m radial distance) and from grain-size analysis of 119 small-scale core samples (~20 cm length each). The permeability determined from the large-scale hydraulic test is 98.9 Darcies. The test also gave a value for specific yield of …


Grain-Size And Permeability Of Sediments Within The Hyporheic Zone At The Theis Environmental Monitoring And Modeling Site, Great Miami River And Buried Valley Aquifer, Southwest Ohio, Usa, Timothy Wayne Cornett Jan 2021

Grain-Size And Permeability Of Sediments Within The Hyporheic Zone At The Theis Environmental Monitoring And Modeling Site, Great Miami River And Buried Valley Aquifer, Southwest Ohio, Usa, Timothy Wayne Cornett

Browse all Theses and Dissertations

The Theis Environmental Monitoring and Modeling Site is a field research facility, located on the Great Miami River in southwest Ohio, dedicated to the study of hyporheic zone processes. The site is underlain by an aquifer on the order of 21 meters thick, comprised of fluvial deposits. The permeability of the aquifer sediments was quantified both from one large scale hydraulic test (~100 m radial distance) and from grain-size analysis of 119 small-scale core samples (~20 cm length each). The permeability determined from the large-scale hydraulic test is 98.9 Darcies. The test also gave a value for specific yield of …


The Legacy Of Contamination By Lead Smelters In Missouri, Robert S. Armstrong Dec 2020

The Legacy Of Contamination By Lead Smelters In Missouri, Robert S. Armstrong

MSU Graduate Theses

Missouri has a rich history of lead mining. In the smelting process lead particles are emitted, which may be toxic to plants and animals. This study focuses on two primary lead smelters, Herculaneum and Glover, in Missouri. Smelting operations have ceased at these two sites, and unlike Herculaneum, Glover has no reported lead concentrations. Findings from air and sediments of these two sites were compared to background conditions and to each other. Thirty-three samples were collected from Herculaneum and Glover (thirty samples and three replicates) and eleven samples (ten samples and one replicate) for background. For Herculaneum sediment, lead levels …


Plant And Soil Responses To Sediment Deposition And Nutrient Enrichment In Healthy, Deteriorating, And Newly Created Coastal Marshes In Barataria Basin, Louisiana: Implications For Mississippi River Sediment Diversions, Gina N. Groseclose Jul 2020

Plant And Soil Responses To Sediment Deposition And Nutrient Enrichment In Healthy, Deteriorating, And Newly Created Coastal Marshes In Barataria Basin, Louisiana: Implications For Mississippi River Sediment Diversions, Gina N. Groseclose

LSU Master's Theses

To offset wetland loss in the Mississippi River Delta, sediment diversions that will re-introduce river water and sediment into wetlands are being planned for the lower Mississippi River. River diversions will also deliver high nutrient loads, which may reduce belowground plant productivity, reducing inputs of organic matter important for marsh accretion to keep pace with sea-level rise. However, belowground productivity responses to the combinatory effects of sediment and nutrients are unknown. To test the hypotheses that nutrient enrichment and sediment deposition interact to influence vegetation structure, belowground plant productivity and decomposition, and surface accretion, a field experiment was implemented in …


Development Of A Hydrodynamic And Sediment Transport Model For Green Bay, Lake Michigan, Bahram Khazaei May 2020

Development Of A Hydrodynamic And Sediment Transport Model For Green Bay, Lake Michigan, Bahram Khazaei

Theses and Dissertations

Sediment dynamics are strongly linked with biogeochemical and physical changes in estuarine systems. Understanding the links between sediment processes and ecosystem responses is necessary for the restoration of degraded systems. Located in Northern US, and one of the largest freshwater estuaries on earth, Green Bay is a distinct example of these degraded systems. Rapid development and anthropogenic activities increased nutrient loading rates into the bay and led to a major disruption of the pre-existing biogeochemical regimes in the ecosystem. Contaminated and nutrient-rich sediments were discharged to the bay by the Fox River for almost half a century. Green Bay’s seasonal-, …


Sedimentary Dynamics And Water Quality In Floodplains Of The Lower Mississippi River Near Natchez, Mississippi, During The 2018 And 2019 Floods, Jansen Costello May 2020

Sedimentary Dynamics And Water Quality In Floodplains Of The Lower Mississippi River Near Natchez, Mississippi, During The 2018 And 2019 Floods, Jansen Costello

Master's Theses

The Lower Mississippi River (LMR) near Natchez, Mississippi, experienced intervals of major flooding during the 2018 and 2019 water years. While federal agencies sample sediment and water quality in the main LMR channel, little is known about sedimentary dynamics, water quality, and nutrient concentrations of the overbank water column within the embanked LMR floodplain. These data are needed to support ecological floodplain restoration efforts and provide context for downstream concerns including sediment delivery to coastal zones and hypoxia in the Gulf of Mexico.

This study monitored the overbank flood pulses and associated sediment deposition along the LMR embanked floodplain during …


Tracing Source Contributions To Assess Spatial Patterns Of Erosion In A Mixed Land Use Environment: Otter Creek Catchment, Fort Knox, Kentucky, Cara Peterman Jan 2020

Tracing Source Contributions To Assess Spatial Patterns Of Erosion In A Mixed Land Use Environment: Otter Creek Catchment, Fort Knox, Kentucky, Cara Peterman

Theses and Dissertations--Earth and Environmental Sciences

There is an inherent difficulty in predicting source contributions of fine-grained fluvial sediment in mixed land-use watersheds. Over a 56-week period, the spatial and temporal variability in sediment-source contributions and water quality was monitored at three sites along Otter Creek in Hardin and Meade counties, Kentucky (USA). The 203-km2 study area drains rural and agricultural lands and includes Fort Knox Army Post’s tracked-vehicle training areas. The main objectives for sediment source apportionment were to 1) identify and differentiate characteristics of civilian and military source soils to Otter Creek and 2) to apportion sediment at locations along Otter Creek to …


Persistence Of Depositional Features In A Strongly Seasonal, Tide-Dominated Delta, Kallie Flaxington Brown Jul 2019

Persistence Of Depositional Features In A Strongly Seasonal, Tide-Dominated Delta, Kallie Flaxington Brown

OES Theses and Dissertations

The Ganges-Brahmaputra-Meghna (GBM) Delta is one of the largest deltas in the world, covering more than 100,000 km2. The GBM River system transports over one billion tons of sediment annually and delivers ~750 million tons to the Bay of Bengal, ~25% of which is advected by tides into the fluvially abandoned western delta plain. The Sundarbans National Forest (SNF) is located within the GBM Delta and, covering more than 10,000 km2, is the world’s largest continuous mangrove stand. The present rate of sediment delivery allows the SNF platform elevation to keep pace with regional sea level …


Dissolved Inorganic Nitrogen Dynamics In Swash Zone Sands Of Long Bay, Sc, Alexis F. Echols Apr 2019

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 …


Characterizing Diatom Biofilms And Their Influence On The Sand Biogeochemistry Of High Energy Beaches, Logan C. Jarrell Oct 2018

Characterizing Diatom Biofilms And Their Influence On The Sand Biogeochemistry Of High Energy Beaches, Logan C. Jarrell

Honors Theses

High energy beaches are among the most dynamic ecological settings on Earth. Compared to mudflats, diatoms of high energy beaches have been more neglected in the literature, particularly true of the intertidal biofilms that form and dissipate with nutrient cycling and light intensity over the tidal cycle. Although short lived, the productivity of these biofilms may be critical to the organic-poor sand. Through sediment coring and subsequent analyses of the uppermost sand of three suspected biofilm stations—non-runnel, runnel crest, and runnel trough—along with seemingly bare sand as a control, this study sought to verify the presence of diatom biofilms and …


Comparative Microbial Community Dynamics In A Karst Aquifer System And Proximal Surface Stream In Northwest Arkansas, Josue Rodriguez Aug 2018

Comparative Microbial Community Dynamics In A Karst Aquifer System And Proximal Surface Stream In Northwest Arkansas, Josue Rodriguez

Graduate Theses and Dissertations

Northwest Arkansas has well-developed karst systems, with numerous sinking streams and springs. Karst conduits make it easy for contaminants to enter groundwater systems, degrading the water quality and destroying fragile karst ecosystems. With the increase of urbanization, potential threats in the form of fecal contamination may prove to be more of a problem. The purpose of this research is to compare the difference between microbial communities within two different settings, a karst aquifer and a surface stream. The microbial communities within Blowing Spring Cave and Little Sugar Creek were detected and identified in water and sediment samples. Samples were also …


The Stability Of Sand Waves In A Tidally-Influenced Shipping Channel, Tampa Bay, Florida, John Willis Gray Mar 2018

The Stability Of Sand Waves In A Tidally-Influenced Shipping Channel, Tampa Bay, Florida, John Willis Gray

USF Tampa Graduate Theses and Dissertations

Tidally-influenced sandwaves are common coastal features present in various settings, including shipping channels. The main shipping channel in Tampa Bay under the Bob Graham Sunshine Skyway Bridge (a.k.a. the Skyway Bridge) contains such sandwave bedforms. Between the years 2000 and 2017, these bedforms have been surveyed with multibeam echosounders (MBES) on 21 occasions with ranging coverage and quality of returns. Surveys between 2000 and 2009 used a 300 kHz Kongsberg EM3000; surveys between 2015 and 2017 used a 400 kHz Reson Seabat 7125. For comparable surveys, bathymetry, backscatter, slope, curvature, planform curvature, and profile curvature maps were created and analyzed. …


The Effects Of Forecasted Climate Change On Mass Wasting Susceptibility In The Nooksack River Basin, Kevin Knapp Jan 2018

The Effects Of Forecasted Climate Change On Mass Wasting Susceptibility In The Nooksack River Basin, Kevin Knapp

WWU Graduate School Collection

The Nooksack River in Whatcom County, Washington­ is an essential fresh water resource for industry, agriculture, municipalities and serves as vital fish habitat. Like many mountainous watersheds in the western Cascades, the Nooksack Basin is susceptible to shallow mass wasting and debris flows because of its steep slopes, young glaciated terrain, and storms with high intensity precipitation. Understanding how projected reductions in snowpack and increased winter rainfall will affect mass-wasting susceptibility in the Nooksack basin is important, because sediment produced mass wasting will jeopardize valuable aquatic and fish habitat, increase flooding risk in the Nooksack River, and affect estuarine and …


Evaluating Potential For Water Quality Decline In Maine Lakes, Kaci N. Fitzgibbon Dec 2017

Evaluating Potential For Water Quality Decline In Maine Lakes, Kaci N. Fitzgibbon

Electronic Theses and Dissertations

Understanding lake vulnerability with respect to eutrophication and loss of water quality is important for sustainability of aquatic ecosystems. This project aims at identifying and quantifying the effects of relevant physiochemical, climate, and watershed characteristics on lake vulnerability in order to develop management decision tools for the Maine Department of Environmental Protection (MEDEP). In a changing chemical and physical environment, using independent variables from each of these categories and then relating them to the summer lake epilimnetic phosphorus (P) concentrations allows for development of models to inform stakeholders of lake vulnerability to eutrophication problems.

We studied 24 lakes covering a …


The Effect Of Watershed Runoff And Sediment Resuspension On Turbidity And Sediment Deposition In St. John, Us Virgin Islands: Implications For Watershed And Marine Development And Restoration In Bays With Coral Reefs, Stephen E. Campbell May 2017

The Effect Of Watershed Runoff And Sediment Resuspension On Turbidity And Sediment Deposition In St. John, Us Virgin Islands: Implications For Watershed And Marine Development And Restoration In Bays With Coral Reefs, Stephen E. Campbell

Theses

In the US Virgin Islands (USVI), land-based (terrigenous) sedimentation has been identified as a major cause of coral stress. Development, such as the building of unpaved roads in steep coastal watersheds, has increased sediment yields and marine terrigenous sedimentation by up to an order of magnitude above background levels. When activated during storm events, ephemeral streams transport sediment from the watershed to coastal waters. Once deposited on the seafloor, resuspension of benthic sediments can further increase turbidity and deposition. However, isolating the relative contributions of runoff and resuspension to turbidity and deposition using conventional sediment trap monitoring has been challenging. …


Sedimentary Responses To Growth Fault Slip And Clay Shrink And Swell Induced Elevation Variations: East Matagorda Peninsula, Texas, Wei Ji Jan 2017

Sedimentary Responses To Growth Fault Slip And Clay Shrink And Swell Induced Elevation Variations: East Matagorda Peninsula, Texas, Wei Ji

Theses and Dissertations--Earth and Environmental Sciences

East Matagorda Peninsula in southwestern Texas is characterized geologically by active, regional-scale and near-surface growth faulting. Decimeter scale (up to 0.42 m) vertical displacement was recorded at the study site over a period of four years, not believed to be associated with growth faulting. This research tested the hypotheses that fault slip rates were correlated with sediment accumulation rates, and that the observed vertical displacement was produced by shrink-and-swell clays in near surface sediments. To quantify sediment accumulation rates, a suite of radionuclides (7Be, 137Cs, and 210Pb) were used. To understand the effects of shrink-and-swell clays, …


Channel Sediment And Mining-Lead Storage In Flat River Creek, Old Lead Belt, Missouri, Ralph Joseph Hill Dec 2016

Channel Sediment And Mining-Lead Storage In Flat River Creek, Old Lead Belt, Missouri, Ralph Joseph Hill

MSU Graduate Theses

Historical mining for lead (Pb) in the Old Lead Belt District introduced large volumes of tailings into nearby streams resulting in the large-scale contamination of channel bed and bar deposits in Big River which drains the southeastern Missouri Ozarks. Tailings pile sites have been remediated so that present contamination sources to the river are primarily from the remobilization of Pb stored in channel and floodplain deposits. This study examined the channel geomorphology and sediment geochemistry of Flat River Creek (FRC), a major tributary to the Big River which drains an area that includes three of the six major mines in …


Microbial Extracellular Enzymes In Marine Sediments: Methods Development And Potential Activities In The Baltic Sea Deep Biosphere, Jenna Marie Schmidt Aug 2016

Microbial Extracellular Enzymes In Marine Sediments: Methods Development And Potential Activities In The Baltic Sea Deep Biosphere, Jenna Marie Schmidt

Masters Theses

The deep biosphere is defined as the subsurface ecosystem in which little energy is available to microorganisms and microorganisms can live for thousands of years. Heterotrophic microbes survive in the deep biosphere even though organic matter is limited and highly recalcitrant in nature. Measuring microbial extracellular enzyme activity provides a potential means to evaluate the rate at which microorganisms are performing carbon remineralization in the energy limited sediment beneath the seafloor. Extracellular enzymes breakdown organic compounds so that the nutrients can move inside the cell and be used for energy. This study explored the role extracellular enzymes play in the …


Role Of Sorting On The Composition Of Siliciclastic Sediment: Implications For Interpreting Provenance After Limited Transport In An Arid Climate, Forrest Christopher Driscoll Aug 2016

Role Of Sorting On The Composition Of Siliciclastic Sediment: Implications For Interpreting Provenance After Limited Transport In An Arid Climate, Forrest Christopher Driscoll

Masters Theses

This study tested whether transport distances (< 500 m) have the capacity to shape the geochemistry of sediments across multiple grain-size populations due to sorting derived from a single source. In the Stepladder Mountains, Mojave Desert, CA, a < 1 km2 [square kilometers] watershed allows for a controlled study to understand how modern sediments acquire their composition from a single granodioritic source in an arid climate where there is no chemical weathering. Sediments are naturally sorted into distinct grain-size populations, with modes ranging from very fine sand to gravel within a single, alluvial channel. Sediment samples representative of each population were petrographically and geochemically analyzed in order to test the effectiveness of commonly used discrimination diagrams. Sediments became proportionally enriched in plagioclase and biotite and depleted in K-feldspar and quartz with decreasing grain …