Digital Commons Network^™

Biochar For Soil Amendment: Applications, Benefits, And Environmental Impacts, Ujjwal Pokharel, Gururaj Neelgund, Ram L. Ray, Venkatesh Balan, Sandeep Kumar

Civil & Environmental Engineering Faculty Publications

The excessive use of chemical fertilizers results in environmental issues, including loss of soil fertility, eutrophication, increased soil acidity, alterations in soil characteristics, and disrupted plant–microbe symbiosis. Here, we synthesize recent studies available from up to 2025, focusing on engineered biochar and its application in addressing issues of soil nutrient imbalance, soil pollution from inorganic and organic pollutants, soil acidification, salinity, and greenhouse gas emissions from fields. Application of engineered biochar enhanced the removal of Cr (VI), Cd²⁺, Ni²⁺, Zn²⁺, Hg²⁺, and Eu³⁺ by 85%, 73%, 57.2%, 12.7%, 99.3%, and 99.2%, …

Water Quality And Microplastic Contamination In An Urbanizing City Nakhon Pathom, Thailand, Boonyarak Chuanchit

Graduate Research Theses & Dissertations

Microplastics (MPs) are synthetic polymer particles less than 5 mm in size that originate from both primary manufacturing and the breakdown of larger plastics. Extensive studies have examined their occurrence in other environments, while little is known about their presence and behavior in groundwater, especially in urbanizing regions in Southeast Asia. This study investigates the occurrence and abundance of microplastics within groundwater systems of Nakhon Pathom, an urbanizing province in central Thailand.

Groundwater was collected representing shallow and deep aquifers between May 2023 and May 2025. The analyses included physical-chemical parameters, major ions, heavy metals, and microplastic abundance and composition. …

Paleomagnetic Assessment Of The Appekunny And Greyson Fms., Lower Belt Supergroup, Montana, Usa., Olivia C. Moehl

Dartmouth College Master’s Theses

The Belt Supergroup of the northwestern United States is one of the most extensive Mesoproterozoic sedimentary successions in North America. Although certain stratigraphic units have been well studied, correlations across the entire outcrop region remain unresolved. This project uses magnetostratigraphy and lithostratigraphy to investigate a potential lateral equivalency between the 1.4 billion-year-old (Ga) Appekunny Formation (Fm.) in Glacier National Park, MT and the 1.4 Ga Greyson Fm. in the Helena Embayment, MT. Both formations consist predominantly of shallow-water mudstones and contain the only North American occurrences of Horodyskia moniliformis, one of the oldest known macrofossils. Paleomagnetic analyses were conducted on …

A Collaborative Assessment Of Coastal Ocean Acidification Monitoring In Maine & Standard Operating Procedures And Best Practices For The Collection Of Continuous Ph Data In Coastal Marine Environments, Christopher W. Hunt, Curtis Bohlen, Mike Doan, Jeremy Miller

Faculty Publications

The ‘Sensor Squad’ of the Maine Ocean Climate Collaborative is the product of a 2023 Maine Coastal and Marine Climate Action Fund grant to conduct “A two-year pilot project designed to address and overcome technological barriers to ocean acidification data collection, develop protocols to elevate quality assurance and ensure comparable data, and meet regularly to discuss project results and data compilation”. The Squad consists of representatives from Friends of Casco Bay (FOCB), Wells National Estuarine Research Reserve (WNERR), and the University of New Hampshire (UNH). This report is a summary of their efforts to assess affordable, repeatable means of continuously …

Constraining The Timing And Degree Of Metamorphism In The Echo Canyon Region: Evidence For A Cryptic Contact Aureole, Keanu Montañez

Graduate Research Theses & Dissertations

Local occurrences of andalusite and kyanite in Echo Canyon, within the Funeral Mountains metamorphic corecomplex, overprint chlorite-grade phyllites and reveal the presence of a hidden pluton and its contact aureole. Phase equilibria models indicate minimum conditions of 0.45 GPa and 535 °C in the highest-grade zone of the aureole, with significantly higher temperatures than previously estimated for the area. This study applied phase equilibria pressure-temperature modeling, petrography, Raman spectroscopy, and ⁴⁰Ar/³⁹Ar geochronology on muscovite to characterize this anomalous metamorphism and to place it within a revised tectonic framework. Two potentially coeval prograde metamorphic events have been recognized based on petrographic …

Geology, Paleoecology And Vertebrate Biostratigraphy Of The Hell Creek Formation, Carter County, Montana, Usa, Joshua Collin Mathews

Graduate Research Theses & Dissertations

The Hell Creek Formation of the Northern Great Plains records one of the greatest mass extinction events in Earth’s history, bringing to a close the reign of the dinosaurs at the end of the Cretaceous period. This rock unit comprises one of the most studied geological formations in the world and is one of the few locations on the planet that preserve terrestrial deposits containing ejecta from the bolide impact that slammed into the Yucatan Peninsula 66 million years ago. This profound event in the geologic record has led to numerous studies of paleobiotas, climate change, ecosystem recovery dynamics, and …

Evaluation Of Strip-Tillage And Banded Phosphorus And Potassium Fertilizer For Corn Production In Eastern South Dakota, Charles N. Tesch

Electronic Theses and Dissertations

In South Dakota, the adoption of no-till and other conservation tillage practices has grown in recent years. However, conventional tillage is still a common practice in the eastern third of the state, negatively affecting soil health and the environment. Strip-tillage has gained interest in this region as a way to transition to conservation tillage while retaining some benefits of conventional tillage. Strip-tillage also provides the ability to subsurface band nutrients, particularly phosphorus (P) and potassium (K) fertilizers within the tillage strip, potentially improving nutrient accessibility and recovery while reducing environmental risks. This study aimed to investigate (i) the effects of …

Depth Distribution Of Liquid Water In Greenlands Firn Layer Based On L-Band Radiometry, A Snow Physics Model, And Machine Learning, Taylor D. Moon

Graduate Student Theses, Dissertations, & Professional Papers

The accurate estimation of the amount of meltwater retained by Greenland’s firn layer and its distribution over depth is essential for assessing both the current and future mass balance of the Greenland Ice Sheet. When meltwater infiltrates the firn, it exists as a quantifiable volume of liquid water, measurable as the one-dimensional liquid water amount, hereafter referred to as LWA. A promising new tool for estimating LWA is L-band passive microwave satellite radiometry, which can provide twice-daily estimates using empirical models of firn microwave emission. However, this method faces two primary limitations. First, retrievals are untested against field observations and …

Changes In Efficiency And Magnitude Of Recharge Due To Climate Change For Headwater Catchments In The Mountain West, Harrison Mcgillen

Graduate Student Theses, Dissertations, & Professional Papers

Changes to groundwater recharge and stream flow were simulated from downscaled CMIP6 global climate models in a headwater catchment of the Blackfoot River, MT. A calibrated, 3-D, coupled surface and groundwater GSFLOW model, forced with minimum and maximum temperature, and precipitation from a downscaled CMIP6 simulation was used to quantify groundwater recharge and stream flow. The model was calibrated against measured groundwater head and stream flow using observed temperature and precipitation boundary conditions. The calibrated model was then forced with downscaled temperature and precipitation from the CANESM5 model for the SSP245, 370 and 585 scenarios, as well as a manual …

Impacts Of Fire-Driven Vegetation Changes On Evapotranspiration In North American Boreal Forests, Tyler Glen Albrethsen

Graduate Student Theses, Dissertations, & Professional Papers

A growing body of evidence suggests that land cover change could be impacting evapotranspiration (ET) trends more than the direct impacts of climate change (Dashti et al., 2022; Zhang et al., 2015). In boreal forests, one of the Earth’s most important carbon sinks (Kang et al., 2006), climate and disturbance-driven land cover change is progressing rapidly, threatening the resilience of conifer-dominated forests (Baltzer et al., 2021; Massey et al., 2023). The spread of deciduous trees and the changing structure of boreal forests likely have large implications for the magnitude and seasonality of ecosystem water fluxes (Young-Robertson et al., 2016). This …

Carbon Sequestration Through Conservation Tillage In Sandy Soils Of Arid And Semi-Arid Climates: A Meta-Analysis, Samantha Lynn Colunga, Leila Wahab, Alejandro Fierro-Cabo, Engil Isadora Pujol Pereira

School of Earth, Environmental, & Marine Sciences Faculty Publications

Highlights

• Under CST, SOC increased by 12.74 ± 1.46 % in sandy soils with 5 of the 6 practices contributing to this rise.
• SOC increased up to 15 years post-CST conversion, but more research is needed to assess long-term effects.
• SOC increased by 13% in soils with over 56% sand content under CST.
• SOC increased by 15% in the 0-20 cm depth under CST, with no significant increase at greater depths.
• SOC increased under CST when nitrogen was applied at rates up to 100 kg N ha⁻¹.

Abstract

This meta-analysis assessed soil organic carbon (SOC) percent changes in sandy soils, …

Assessing Inter-Organizational Collaboration Within The Transboundary Network Governing The Conservation Of Southern Resident Killer Whales, Dane Pedersen, Owen Temby, Antonia Sohns, Evelyn Roozee, Gordon M. Hickey

School of Earth, Environmental, & Marine Sciences Faculty Publications

The Southern Resident Killer Whale (SRKW) is an endangered and charismatic species whose home range spans the Salish Sea, an ecosystem that extends across the Canada-US border. Conserving and recovering the SRKW represents a high-profile transboundary governance challenge that depends heavily on collaboration between a wide range of organizations. To better understand the factors affecting transboundary SRKW governance in the Salish Sea, this study applies a multi-dimensional trust, control, perceived risk framework to assess the inter-organizational architecture supporting collaboration. The analysis is based on key informant interviews (n=32) and surveys (n=35) conducted with policy actors working for different organizations involved …

Isolation And Molecular Identification Of Pathogens Causing Sea Turtle Egg Fusariosis In Key Nesting Beaches In Costa Rica, Keilor E. Cordero-Umaña, Ruth Hernando-Martínez, María Martínez-Ríos, Jaime Restrepo, Roldán A. Valverde, Laura Martín-Torrijos, Pilar Santidrián Tomillo, Javier Diéguez-Uribeondo

School of Earth, Environmental, & Marine Sciences Faculty Publications

The global rise of fungal pathogens presents an emerging threat to biodiversity, with significant risks to species such as endangered sea turtles. The fungal disease known as sea turtle egg fusariosis (STEF) is associated with high embryo mortality rates and represents a substantial conservation challenge. This disease is caused by two fungal species, namely Fusarium falciforme (Ff) and Fusarium keratoplasticum (Fk), and their identification is essential for guiding future efforts to address potential fungal infections, particularly on important nesting beaches such as those in Costa Rica. In this study, we conducted fungal isolations from sea turtle eggshells …

Examining The Presence And Effects Of Coherence And Fragmentation In The Gulf Of Maine Fishery Management Network, Derek A. Katznelson, Antonia Sohns, Dongkyu Kim, Evelyn Roozee, William Donner, Andrew M. Song, Jasper R. De Vries, Owen Temby, Gordon M. Hickey

School of Earth, Environmental, & Marine Sciences Faculty Publications

Natural resource management networks cohere due to mutual dependencies and fragment, in part, due to the perceived risks of interaction. However, research on these networks has tended to accept coherence a priori rather than problematizing dependence, and few studies exist on interorganizational risk perception. This article presents the results of a study operationalizing these concepts and measuring the distribution of three types of dependence (capital, legitimacy, and regulatory) and two types of perceived risk (performance and sanction) among nearly fifty stakeholder groups and organizations participating in the management of fisheries in the binational Gulf of Maine. The analysis reveals an …

The Large-Scale Flow Dynamics And Controls On Recurving Eastern North Pacific Tropical Cyclones, Alexander Kyle Mitchell

Electronic Theses & Dissertations (2024 - present)

While eastern North Pacific (EPAC) tropical cyclones (TCs) most often move westward over open water, a subset deviates from this typical path, recurving toward higher latitudes or making landfall along the North American coastline. Because such events are relatively rare, they have received less attention, despite their significant contributions to rainfall and wildfire activity across the southwestern United States. This dissertation identifies and characterizes the spatial variability of EPAC TC tracks, analyzes the synoptic environments associated with TC recurvature near the North American coast, presents a detailed case study of two recurving EPAC TCs from late September to early October …

Fault Box Modeling Of Dip Slip Faults: A Framework For Fault Box Design And Future Studies, Hailey Pressnell

Master's Theses

The behavior of soils during surface fault rupture is a serious concern in the planning and design of infrastructure that may be located within or near a fault zone. Challenges associated with developing mitigation measures for surface fault rupture include the uncertainty of fault rupture and the variability of fault behavior. Current analytical procedures define surface fault rupture according to the type of fault movement (strike slip, normal or reverse), the amount of displacement on the fault, and the mechanics of the material overlying the fault. The purpose of this thesis is to reconfirm analytical solutions and gain a better …

Elucidating Non-Canonical Interactions Of Mcl1 With The P53 Family Of Tumor Suppressors, Alexus Marie Acton

All ETDs from UAB

Various signaling mechanisms contribute to a cancers cell’s ability to survive through the stressors of tumorigenesis. Canonically, when a cell is exposed to irreversible stress, the induction to apoptosis is regulated by the Bcl-2 family of apoptotic regulators. However, to accommodate for the stressors of tumor progression, many solid tumors over express one of the pro-survival proteins (e.g., BCL2, BCLxL, MCL1) allowing for persistent growth without the induction to cell death. Over the past 10 years, researchers have investigated how over expression of these pro-survival proteins contribute to chemoresistance to standard of care therapies. To sensitize cells to these apoptotic …

Provenance Of The Uppermost Carboniferous–Lower Triassic Sandstones, Bogda Mountains, Nw China: Implications On The Late Paleozoic Tectonic History Of The Southern Central Asian Orogenic Belt, Sixuan Wu

Doctoral Dissertations

"The Permian-Triassic period represents a significant but insufficiently understood tectonic transition stage in the southern Central Asian Orogenic Belt (CAOB) between the Paleozoic continental amalgamation and Cenozoic orogenic reactivation. This study integrates fieldwork, petrographic, and detrital zircon geochronological data to document the trend of depositional environments, framework grain compositions, and dates of detrital zircon grains of the uppermost Carboniferous–Lower Triassic sandstones from three study areas in Bogda Mountains, the greater Turpan-Junggar basin, NW China, to decipher the spatial and temporal changes in the provenance lithology and area and reconstruct the unroofing history of the southern CAOB.

In the first part …

The Petrology And Geochemistry Of The Montagna Grande-Monte Gibele Trachytic Shield Volcano (Pantelleria, Italy)., John C. White, Ray Macdonald, Pierangelo Romano, Boguslaw Baginski, Silvio G. Rotolo, Beata Marciniak-Maliszewska, Alessandra Cinquegrani

EKU Faculty and Staff Scholarship

The 45.7 ± 1.0 ka (2σ) eruption of the compositionally zoned (comenditic trachyte to pantellerite) Green Tuff ignimbrite on the volcanic island of Pantelleria, Italy, was followed by the extrusion of a series of post-caldera metaluminous to mildly peralkaline trachyte lavas between 26.2 ± 2.0 and 22.3 ± 2.9 ka (2σ). This study uses whole-rock major- and trace-element compositions, mineral compositions, geothermobarometry, and petrogenetic models to examine the role of trachytes in the evolution of the Pantelleria magma system. Although previous studies have suggested that all of these units are consanguineous and form a liquid line of descent (LLOD) from …

Sulfate Sources In Groundwater From An Agricultural Area Central Illinois, Christabel I. Obi

Theses and Dissertations

Increasing sulfate (SO₄^2-) concentrations in the water environment, corresponding with increases in urbanization and industrialization, are a rising global concern. Over 250 mg/L, sulfate threatens human health and ecosystems. Elevated concentrations influence carbonate rock weathering, contributing to the evolution of the global carbon cycle. Knowledge of sulfate sources, whether natural or anthropogenic, is essential for understanding sulfate transport and fate in groundwater. This study investigates SO₄^2- origin and transport in groundwater in an area dominated by agricultural land use in Mclean County, Illinois. Specifically, we explored these questions: 1) Do sulfate concentrations change with groundwater …

Efficacy Of Stress Acclimation Techniques In Coastal Wetland Plants (Spartina Alterniflora And S. Patens): Implications For Restoration And Nursery Production, Taylor M. Sloey, Kylie D. Gieser, Kaitlyn Pounders, Sofía E. Báez, Jennifer L. Whytlaw

Biological Sciences Faculty Publications

The implementation of coastal nature-based features, created wetlands, and wetland restoration has increased globally over recent years. Many of these projects have been successful in meeting their goals, however, when projects fail, it is often attributed to mortality of transplanted vegetation. Transplant mortality may be due to inappropriate timing, poor site selection, or abiotic stressors associated with transplant shock. Science-backed guidelines have been well established in many coastal regions regarding site specifications and species selection, but nursery practices for reducing transplant shock remain inconsistent. In this study, we tested a combination of four salinity acclimation treatments and two inundation acclimation …

Contribution Of Different Frass Fertilizer Products On Enhanced Growth, Yield And Nutrient Quality Of Broccoli [Brassica Oleracea], Noella Kagehi, Dennis Beesigamukama, Chrysantus M. Tanga, Mathew P. Ngugi, Sevgan Subramanian, Fathiya M. Khamis

All Peer-Reviewed Publications

Vegetables are crucial for food security and income, but in developing countries their production is hindered by low soil fertility. Although the insect frass fertilizer is a potential solution, its use is constrained by limited product choices. Unlike conventional fertilizers, which are available in different forms, the insect frass fertilizer is mostly available in solid form. Here, we evaluated the effects of different black soldier fly frass fertilizer (BSFFF) products on broccoli [Brassica oleracea] growth, yield, and nutritional profiles. Solid, liquid BSFFF, chitin-fortified solid BSFFF, chitin-fortified liquid BSFFF, and commercial organic fertilizer (Safi) were applied at rates equivalent to 250 …

Groundwater Pumping Impacts On Stream Depletion In Humboldt County, Ca: Integrating Analytical Models And Field Data, Andy Hans Heise

Cal Poly Humboldt theses and projects

This study addresses the significant concern of stream depletion from groundwater pumping in Humboldt County, CA. The objective of this study is to develop an analytical model for estimating stream depletion and integrating field data into model parameters.

The methodology involved conducting a field study near three operating wells by a stream, installing stream gages upstream and downstream of the wells, and recording pumping rates and schedules for two of the wells. The third well’s pumping data was synthetically generated, for privacy concerns of the well owner. The StreamDepletR package was used for estimating depletion rates in a stream in …

Fewer Wetlands, More Drainage: Forensic Mapping Of Wetland Loss And Drainage Alteration Illustrates The Hydrological Transformation Of Coastal Watersheds, Kai C. Rains, Seanacy A. Lawlor, Edgar J. Guerron-Orejuela, Shawn M. Landry, W J. Kleindl, Mark C. Rains

School of Geosciences Faculty and Staff Publications

Land use-land cover (LULC) change is widely implicated in coastal water quality degradation, but we often lack understanding of how LULC change has varied spatiotemporally because so much change occurred before the advent of modern mapping. In this study, we overcome this challenge by using forensic mapping techniques of LULC change over the past 175 years in coastal watersheds on the Atlantic Coast of Florida, USA. We benchmark historical mapping products to modern mapping standards using historical products. These include maps and notes from the Public Land Survey System, military campaigns, and navigation surveys from the nineteenth century, and aerial …

Evaluating The Causes Of Land Subsidence On The U.S. Mid-Atlantic Coast Measured With Insar, Jordan Leigh Diprima

Honors Theses and Capstones

Land subsidence is a frequently overlooked geologic hazard that is caused by natural processes and anthropogenic stressors. The goal of this study is to quantify vertical land motion (VLM) on Long Island, New York and Virginia’s Eastern Shore and evaluate the potential causes of subsidence. The causes considered in this work are glacial isostatic adjustment, groundwater extraction, infrastructure loading, and land cover. This study utilizes interferometric synthetic aperture radar (InSAR) satellite data from Sentinel-1 to calculate linear VLM trends from 2017 to 2023. Datasets for each hypothesis were qualitatively compared to VLM data. Subsidence rates in both regions were found …

The Role Of Floodplain Complexity In Wood Turtle Habitat Use, Laura S. Deming

Antioch University Dissertations & Theses

Wood turtles occupy cold, low-gradient riverine habitat throughout the northeastern United State and southeastern Canada. Stream alterations, such as dams, channel straightening, and floodplain development have diminished the natural hydrologic and sedimentation regimes that result in complex channel and floodplain geomorphology. Studies throughout the species’ range have quantified many aspects of their habitat, but none have quantified components of geomorphology of wood turtle sites. The goal of this study was to explore the role of stream channel and floodplain geomorphology in wood turtle habitat use, with specific objectives to (1) quantify components of stream channel and floodplain geomorphic complexity, (2) …

Kinetic Grain Growth In Firn Induced By Meltwater Infiltration On The Greenland Ice Sheet, Kirsten Leigh Gehl

Graduate Student Theses, Dissertations, & Professional Papers

The microstructure of polar firn governs its porosity, permeability, and compaction rate, and is therefore important to studies of surface elevation change, heat and gas exchange, and meltwater infiltration on ice sheets. Previous work on high-elevation, dry-firn has identified two distinct atmospheric drivers of kinetic grain growth in deposited snow, but both mechanisms result in near-surface mm-scale layers. In this work, we show that meltwater infiltration through surface wetting fronts and deep preferential flow in the Greenland Ice Sheet (GrIS) percolation zone leads to the formation and preservation of centi- to decimeter scale layers of faceted firn, ranging from faceted …

Fluvial Geomorphic Resilience In Alluvial Mountain Rivers To Large Floods, Riley T. Henson

Graduate Student Theses, Dissertations, & Professional Papers

As hydroclimatic extremes intensify, large floods increasingly reshape river systems and threaten infrastructure. Fluvial geomorphic resilience, defined as a river’s resistance to, and recovery from, flood disturbance, offers a useful framework for understanding river response and guiding management. We assessed resilience at two scales: (1) a detailed geomorphic and hydraulic analysis of the June 2022 flood on East Rosebud Creek, Montana, which was part of broader flooding in the Greater Yellowstone Ecosystem, and (2) a broad-scale comparison of 12 flood-impacted alluvial mountain rivers across North America and Europe. We quantified resistance using active channel width ratios (W_R) and …

Controls Of Wetland Hydrology In The Zone Of Discontinuous Permafrost, Northwest Territories, Canada, Iain Thomson

Theses and Dissertations (Comprehensive)

Mean annual air temperatures are increasing rapidly in northwestern Canada, which is among the most rapidly warming regions on Earth (Box et al., 2019). Consequently, permafrost thaw within northwestern Canada is proceeding at a rate not found in the historical record (Pelletier et al., 2017), with areal thaw rates especially high in the peatland-dominated southern margin of discontinuous permafrost (Quinton et al., 2019). Permafrost thaw has caused vast land cover changes and transformed the permafrost underlain forest into permafrost free wetlands over much of Taiga Plains (Carpino et al., 2018; Jorgenson & Osterkamp, 2005). This land cover change has …

Multi-Source Remote Sensing–Based Soil Moisture Prediction Using Machine Learning, Niraj Neupane

Electronic Theses and Dissertations

Soil moisture (SM) plays a central role in climatic and environmental processes, influencing shear strength of soil, agricultural productivity, land–atmosphere interactions, and hydrologic functioning. However, accurately estimating SM across diverse climatic regions remains challenging due to spatial heterogeneity, limited in situ measurements, and inconsistencies in sensor resolution. Machine learning (ML) and remote sensing offer promising avenues for improving SM prediction, yet many existing approaches struggle with generalization across climatic gradients and often fail to capture temporal variability. This study integrates multi-source satellite and climate datasets, including SMAP L4_SM, MODIS land surface temperature, Daymet meteorological variables, and in situ observations from …