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Full-Text Articles in Physical Sciences and Mathematics

Hydrological Feedbacks On Peatland Ch4 Emission Under Warming And Elevated Co2: A Modeling Study, Fenghui Yuan, Yihui Wang, Daniel M. Ricciuto, Xiaoying Shi, Fengming Yuan, Thomas Brehme, Scott Bridgham, Jason Keller, Jeffrey M. Warren, Natalie A. Griffiths, Stephen D. Sebestyen, Paul J. Hanson, Peter E. Thornton, Xiaofeng Xu Nov 2021

Hydrological Feedbacks On Peatland Ch4 Emission Under Warming And Elevated Co2: A Modeling Study, Fenghui Yuan, Yihui Wang, Daniel M. Ricciuto, Xiaoying Shi, Fengming Yuan, Thomas Brehme, Scott Bridgham, Jason Keller, Jeffrey M. Warren, Natalie A. Griffiths, Stephen D. Sebestyen, Paul J. Hanson, Peter E. Thornton, Xiaofeng Xu

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Peatland carbon cycling is critical for the land–atmosphere exchange of greenhouse gases, particularly under changing environments. Warming and elevated atmospheric carbon dioxide (eCO2) concentrations directly enhance peatland methane (CH4) emission, and indirectly affect CH4 processes by altering hydrological conditions. An ecosystem model ELM-SPRUCE, the land model of the E3SM model, was used to understand the hydrological feedback mechanisms on CH4 emission in a temperate peatland under a warming gradient and eCO2 treatments. We found that the water table level was a critical regulator of hydrological feedbacks that affect peatland CH4 dynamics; the …


Spatiotemporal Variability Of Soil Water Δ18o And Δ2h Reveals Hydrological Processes In Two Floodplain Soils, Amanda Ceming-Barbato Sep 2021

Spatiotemporal Variability Of Soil Water Δ18o And Δ2h Reveals Hydrological Processes In Two Floodplain Soils, Amanda Ceming-Barbato

LSU Master's Theses

The movement of water through soil is preferential and heterogeneous. Subsurface interactions between mobile flows and the soil matrix are not uniform and are therefore difficult to predict through time and space. The use of stable isotopes of hydrogen (2H) and oxygen (18O) as conservative tracers of water movement is improving understanding of soil hydrological processes, yet field-scale observations of isotopic variability remain scarce despite implications for identifying dominant hydrologic processes. We sampled two adjacent soils at a ridge-swale topography floodplain forest to determine soil water isotopic variability at a 20 cm depth resolution in soils …


High-Resolution Timeseries Analysis Of Dynamic Geochemistry: A 27-Well Survey Of Contaminated Groundwater Downstream Of The Former S-3 Ponds, Oak Ridge, Tennessee, Emma Dixon Aug 2020

High-Resolution Timeseries Analysis Of Dynamic Geochemistry: A 27-Well Survey Of Contaminated Groundwater Downstream Of The Former S-3 Ponds, Oak Ridge, Tennessee, Emma Dixon

Masters Theses

Spatiotemporal variability of geochemistry of contaminated groundwater has large implications on overall water quality and ability to respond to remedial applications. Gaining knowledge of how geochemistry changes over time in an area can help establish response trends to changing external conditions like weather and level of contamination. In this study, a spatiotemporal survey was performed on 27 wells at the Y-12 Complex in Oak Ridge, Tennessee. This was completed to measure diurnal fluxes in geochemistry from seasonal changes and extreme weather conditions in three areas of historically different contamination levels from a single point contamination source. Measurements were gathered over …


Geochemical Flux Analysis Of Glacial River Runoff For Sólheimajökull, Iceland, Jessica Garrison Jan 2020

Geochemical Flux Analysis Of Glacial River Runoff For Sólheimajökull, Iceland, Jessica Garrison

Mahurin Honors College Capstone Experience/Thesis Projects

Geochemical fluxes in aqueous studies are an essential component of research to understand weathering and changes in a hydrologic system. These data can indicate any discrepancies, outliers, or gradual changes in a water environment to gain information on pollutants, carbon cycles, biological input, etc. Glacial melt is the majority of the surface water present throughout the country. The melting amount is increasing with the temperatures, which can be monitored by the changes in geochemical flux during increased discharge in glacial rivers. A high-resolution data set of Sόlheimajökull Glacier in Iceland was used to determine how changing climatic conditions for the …


Groundwater Hydrogeolgy And Hydrochemistry Of Karst Springs In The Eastern Peninsula Of Fort Hood Military Installation, William Scribner Welles Dec 2018

Groundwater Hydrogeolgy And Hydrochemistry Of Karst Springs In The Eastern Peninsula Of Fort Hood Military Installation, William Scribner Welles

Electronic Theses and Dissertations

The eastern peninsula of Fort Hood Military Installation is underlain by a complex karst spring network. These springs are a primary water source in a protected habitat for endangered songbirds, which has only recently begun to be fully investigated. These Fredericksburg Group springs express both epigenetic and hypogenetic karst signatures. The study area is part of a paleo reef trend, a hydraulically disconnected segment of the northern section of the Edwards Aquifer. This study utilized standard ion index values, repeated measures, and principal component analyses on the chemical profiles of six perennial springs to classify spring water sources and their …


Geochemical Dynamics And Nitrous Oxide Release From The Hyporheic Zone Of Streams, Annika Marie Quick May 2018

Geochemical Dynamics And Nitrous Oxide Release From The Hyporheic Zone Of Streams, Annika Marie Quick

Boise State University Theses and Dissertations

The hyporheic zones of streams and rivers, consisting of the sediments beneath and immediately adjacent to the stream channel, are an important site of geochemical processing. Due to the difficulty of measuring these geochemical processes in the hyporheic zone in situ with meaningful spatial and temporal resolution, we conducted multiple column and large-scale flume experiments to model 1D and 2D hyporheic flow paths and observed important geochemical reactions, including the production and consumption of nitrous oxide (N2O). N2O is a significant greenhouse gas, but the controls on its emissions from streams are poorly constrained. We describe …


Evaluating Ecohydrological Separation With Geochemical Tracers, Δ2h And Δ18o, From Northern California In An Irrigated And Semi-Arid Setting, Erin Bulson May 2018

Evaluating Ecohydrological Separation With Geochemical Tracers, Δ2h And Δ18o, From Northern California In An Irrigated And Semi-Arid Setting, Erin Bulson

Theses and Dissertations

The two water worlds hypothesis challenges the widely accepted ecohydrology tenet that plant roots access a single, homogeneous reservoir of soil water (McDonnell, 2014). This project aspired to advance the understanding of the two water worlds, or ecohydrological separation (ES) of soil water reservoirs, applied to an irrigated agricultural setting. This study also aimed to correlate plant root morphology with plant water uptake. Using geochemical tracers, δ2H and δ18O, isotopic analysis of soil and plant tissue was used to evaluate irrigated plant water acquisition. Field work was conducted on two irrigated farms, Full Belly Farm and Riverdog Farm, in the …


Sources Of Water And Solutes To The Salar De Atacama, Chile: A Coupled Hydrologic, Geochemical, And Groundwater Modeling Study, Lilly G. Corenthal Mar 2016

Sources Of Water And Solutes To The Salar De Atacama, Chile: A Coupled Hydrologic, Geochemical, And Groundwater Modeling Study, Lilly G. Corenthal

Masters Theses

Focused groundwater discharge in endorheic basins provides opportunities to investigate mechanisms for closing hydrologic budgets in arid regions. The Salar de Atacama (SdA), a closed basin in northern Chile, has accumulated over 1800 km3 of halite and a lithium-rich brine since the late Miocene primarily through evapotranspiration of groundwater. The hydrologic balance of SdA and sources of water and solutes required to explain this deposit are not well constrained. An adapted chloride mass balance method drawing on a database of over 200 water sample sites is applied to a remotely-sensed precipitation dataset to estimate spatially-distributed modern groundwater recharge. Comparing …


Hydrologic Controls Of Coastal Groundwater Discharge In Southern Taylor Slough, Everglades National Park, Florida, Edward Linden Jul 2015

Hydrologic Controls Of Coastal Groundwater Discharge In Southern Taylor Slough, Everglades National Park, Florida, Edward Linden

FIU Electronic Theses and Dissertations

This project empirically determined the controls of groundwater discharge potential and surface water chemistry in southern Taylor Slough, Everglades National Park, Florida. Potential for groundwater discharge was calculated as the difference in equivalent freshwater stage between groundwater and surface water on a daily basis for two sites (upland and coastal) along southern Taylor Slough. Upstream water stages were shown to vary most similarly to the timing of groundwater discharge potential in coastal Taylor Slough. Surface water major ion chemistry did not apparently change as a result of groundwater discharge potential. Surface water major ion chemistry at the coastal site was …


Runoff Generation In A Tropical Dry Forest Watershed: Processes, Patterns And Connectivity, Kegan K. Farrick Nov 2014

Runoff Generation In A Tropical Dry Forest Watershed: Processes, Patterns And Connectivity, Kegan K. Farrick

Electronic Thesis and Dissertation Repository

The lack of understanding regarding the controls that govern runoff generation in tropical dry forests represent a critical gap in the hillslope and catchment hydrology literature. Tropical dry forests account for approximately 42% of the global tropical forests, but represent less than 1% of the forest hydrology literature. Three complementary studies were undertaken in a small tropical dry forest watershed, Mexico, to assess the controls that govern the retention and release of a rainfall in the catchment as runoff. In the first study, the high soil surface hydraulic conductivities, absence of a water repellent surface and low rainfall intensities during …


Carbon Cycling Dynamics Inferred From Carbon Isotope Sourcing In A Mid-Latitude Karst-Influenced River, Kegan N. Mcclanahan Aug 2014

Carbon Cycling Dynamics Inferred From Carbon Isotope Sourcing In A Mid-Latitude Karst-Influenced River, Kegan N. Mcclanahan

Masters Theses & Specialist Projects

As ever-increasing levels of carbon dioxide alter the chemistry of the Earth’s atmosphere, understanding the global carbon cycle becomes increasingly important. A particularly important component is the riverine carbon cycle, as rivers are the primary conduits for dissolved inorganic carbon from terrestrial watersheds to ocean basins. Stable carbon isotopes (13C/12C) were collected weekly and input into the mixing model IsoSource to delineate seasonal carbon sourcing along two nested basins in the upper Green River System, Kentucky. In the more siliciclastic upstream catchment, dissolved inorganic carbon (DIC) was primarily derived from soil respiration (34%). Groundwater dissolving carbonate bedrock and carbonate dissolution/precipitation …


Investigating Telogenetic Karst Aquifer Processes And Evolution In South-Central Kentucky, U.S., Using High-Resolution Storm Hydrology And Geochemistry Monitoring, Nicholas Lawhon May 2014

Investigating Telogenetic Karst Aquifer Processes And Evolution In South-Central Kentucky, U.S., Using High-Resolution Storm Hydrology And Geochemistry Monitoring, Nicholas Lawhon

Masters Theses & Specialist Projects

Recent studies have investigated the hydrological and geochemical characteristics of karst aquifers in different settings; however, telogenetic karst aquifer processes remain poorly understood. In south-central Kentucky, the iconic Lost River Cave and Valley represents a large, complex telogenetic karst drainage basin with a series of discharge points along a collapsed section of the cave. Two Campbell Scientific® CR1000 automated dataloggers were installed at Blue Hole Four, a primary discharge point of the Lost River Karst Aquifer (LRKA). These dataloggers recorded spring discharge, water temperature, specific conductance (SpC), and pH at ten-minute intervals from January to November, 2013. During the year, …


Exploring The Hydrogeologic Controls On Brackish Water And Its Suitability For Use In Hydraulic Fracturing: The Dockum Aquifer, Midland Basin Texas, Francisco Ruben Reyes Jan 2014

Exploring The Hydrogeologic Controls On Brackish Water And Its Suitability For Use In Hydraulic Fracturing: The Dockum Aquifer, Midland Basin Texas, Francisco Ruben Reyes

Open Access Theses & Dissertations

Water scarcity in arid regions can limit or impede certain hydrocarbon production activities, such as hydraulic fracturing and well drilling. The Midland Basin, a major oil-producing area in semi-arid far west Texas and the eastern sub-basin of the Permian Basin, is already impacted by limited freshwater availability. A typical tight oil well in the Midland Basin requires ~3.8-11.4 x 103 m3 of water per fracture treatment (Nicot et al., 2012). Despite draught conditions and limited resources, data for 2011 indicate freshwater comprises ~70% of the water used in hydraulic fracturing in the Midland basin. Thus, the Midland Basin represents an …


Sources Of Co2 Controlling The Carbonate Chemistry Of The Logsdon River, Mammoth Cave, Kentucky, Bruce Elliott Hatcher Dec 2013

Sources Of Co2 Controlling The Carbonate Chemistry Of The Logsdon River, Mammoth Cave, Kentucky, Bruce Elliott Hatcher

Masters Theses & Specialist Projects

Logsdon River is a major, base-level stream within the Turnhole Bend Drainage basin of the Mammoth Cave System. The Logsdon River system has provided a unique opportunity to examine the geochemical evolution of a stream flowing through a major karst conduit that can be traversed for 10 km. This study examines CO2 inputs at the upstream portion of the river, which provide major control for the river’s hydrochemistry. Samples were collected from the upstream portion of Logsdon River at what is referred to as the S-188 sump and also nearby at Crowbar Dome over the course of 44 weeks …


Geochemical Constraints On Groundwater Recharge In The Royal Slope Area, Grant County, Washington, Zoe Danielle Weis Dec 2012

Geochemical Constraints On Groundwater Recharge In The Royal Slope Area, Grant County, Washington, Zoe Danielle Weis

All Master's Theses

Groundwater, the primary source for potable water in the Columbia Plateau, has experienced significant declines over the past 25 years. Groundwater geochemistry and multivariable statistics were employed to identify and characterize the hydrofacies present, constrain recharge sources, and assess mixing of groundwater in the Royal Slope area of the Columbia Plateau. Geochemical analyses for major ions, stable isotopes, and radiogenic isotopes (14C and tritium) for age dating were performed on groundwater samples collected in 2010 from 24 wells in the study area. The results confirmed that the groundwater evolution in the study area follows the typical Columbia River Basalt Group …


Examination Of Selected Microparticles From The Sentik Glacier Core, Ladakh, Himalayas, Emily Goss, Paul Andrew Mayewski, William Berry Lyons Jan 1985

Examination Of Selected Microparticles From The Sentik Glacier Core, Ladakh, Himalayas, Emily Goss, Paul Andrew Mayewski, William Berry Lyons

Earth Science Faculty Scholarship

Several characteristics and interpretive comments are reported for microparticles from selected samples in the Sentik Glacier core. Four basic morphologic groups are defined: Platy, angular, biogenic, and anomalous.


Interpretation Of The Chemical And Physical Time-Series Retrieved From Sentik Glacier, Ladakh Himalaya, India, Paul Andrew Mayewski, N. Ahmad, Gordon Smith, M. Pourchet Jan 1984

Interpretation Of The Chemical And Physical Time-Series Retrieved From Sentik Glacier, Ladakh Himalaya, India, Paul Andrew Mayewski, N. Ahmad, Gordon Smith, M. Pourchet

Earth Science Faculty Scholarship

Spectral analysis of time series of a c. 17 ± 0.3 year core, calibrated for total β activity recovered from Sentik Glacier (4908 m) Ladakh, Himalaya, yields several recognizable periodicities including sub-annual, annual, and multi-annual. The time-series, include both chemical data (chloride, sodium, reactive iron, reactive silicate, reactive phosphate, ammonium, δD, δ(18O) and pH) and physical data (density, debris and ice-band locations, and microparticles in size grades 0.50 to 12.70 μm). Source areas for chemical species investigated and general air-mass circulation defined from chemical and physical time-series are discussed to demonstrate the potential of such studies in the …