Digital Commons Network^™

Marine Emissions Of Methanethiol Increase Aerosol Cooling In The Southern Ocean, Charel Wohl, Julián Villamayor, Martí Galí, Anoop S. Mahajan, Rafael P. Fernández, Carlos A. Cuevas, Adriana Bossolasco, Qinyi Li, Anthony J. Kettle, Tara Williams, Roland Sarda-Esteve, Valérie Gros, Rafel Simó, Alfonso Saiz-Lopez

OES Faculty Publications

Ocean-emitted dimethyl sulfide (DMS) is a major source of climate-cooling aerosols. However, most of the marine biogenic sulfur cycling is not routed to DMS but to methanethiol (MeSH), another volatile whose reactivity has hitherto hampered measurements. Therefore, the global emissions and climate impact of MeSH remain unexplored. We compiled a database of seawater MeSH concentrations, identified their statistical predictors, and produced monthly fields of global marine MeSH emissions adding to DMS emissions. Implemented into a global chemistry-climate model, MeSH emissions increase the sulfate aerosol burden by 30 to 70% over the Southern Ocean and enhance the aerosol cooling effect while …

Contrasting Nitrogen Dynamics Across The Mid-Atlantic Bight Shelfbreak Front: Insights From Nitrate Dual Isotopes And Nitrifier Gene Abundance, Yifan Zhu, Margaret R. Mulholland, Corday R. Selden, Dennis J. Mcgillicuddy Jr., Josie Mottram, P. Dreux Chappell, Weifang Gordon Zhang, Julie Granger, Katherine E. Crider, Meredith G. Meyer, Peter W. Bernhardt, Hilde Oliver, Sophie Clayton

OES Faculty Publications

Observations and model studies suggest that front dynamics can enhance phytoplankton productivity. This study tested whether frontal systems also increase the abundance of nitrifying microbes and nitrogen recycling during repeat sampling transects across the Mid‐Atlantic Bight shelfbreak in July 2019. We measured ammonium concentrations, nitrate dual isotopes (δ¹⁵N, δ¹⁸O), and ammonia monooxygenase subunit A (amoA) genes of ammonia‐oxidizing archaea (AOA) and bacteria (AOB). In subsurface shelf waters, ammonium concentrations exceeded 2 μmol L⁻¹, due to a temporary imbalance in regeneration from sinking particles and subsequent nitrification. The inverse correlation between nitrate δ^{15 …}

Submarine Groundwater Discharge As A Major Nutrient Source In River-Fed Vs. Tidally Dominated Estuaries, Stephanie J. Wilson, Joseph J. Tamborski, Bongkeun Song, Peter Bernhardt, Margaret R. Mulholland

OES Faculty Publications

The tidal tributaries of the lower Chesapeake Bay experience seasonally recurring harmful algal blooms and the significance of submarine groundwater discharge (SGD) as a nutrient vector is largely unknown. Here, we determined seasonal SGD nutrient loads in two tributaries with contrasting hydrodynamic conditions, river-fed (York River) vs. tidally dominated (Lafayette River). Radon surveys were performed in each river to quantify SGD at the embayment-scale during spring and fall 2021. Total SGD was determined from a ²²²Rn mass balance and Monte Carlo simulations. Submarine groundwater discharge rates differed by a factor of two during spring (Lafayette = 11 ± 17 cm …

Factors Affecting Electrocoagulation Process For Different Water Types: A Review, Shahad Fadhil Abed Al-Rubaye, Naseer A. Alhaboubi, Aiman H. Al-Allaq

Mechanical & Aerospace Engineering Faculty Publications

Raw water must meet specific physical, chemical, and biological requirements to be suitable for drinking. There are various techniques available for treating wastewater, and aside from conventional methods that involve chemicals, electrocoagulation is an efficient and advanced approach. Electrocoagulation has proven effective in treating many pollutants, including bacteria, viruses, iron, fluoride, sulfate, boron, hardness, and turbidity. Total suspended solids, organic and inorganic materials, chemical oxygen demand COD, biochemical oxygen demand BOD, and color. It finds extensive application in treating different types of water and wastewater due to its exceptional ability to remove diverse contaminants. Recently, electrocoagulation has garnered significant attention …

Environmental Reconstruction In Nong Thale Pron, Nakhon Si Thammarat Province, Kanokpon Surijamorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

Climate change is one of the major factors influencing environmental changes. The study of proxies from geological records can extend climate data into the past, enabling the reconstruction of past environmental changes. This study collected sediment cores from three points at the deepest part of Nong Thale Pron, Nakhon Si Thammarat Province. The sediment core NTP-CP6 was selected for analysis using X-ray fluorescence (XRF), radiocarbon dating, grain size analysis, total organic carbon, total nitrogen, stable carbon isotopes, and n-alkanes. During the Last Glacial Maximum (21–19 ka BP), dry conditions were caused by a strong northeast monsoon and the exposure of …

Leveraging High Resolution Classifications And Random Forests For Hindcasting Decades Of Mesic Ecosystem Dynamics In The Landsat Time Series, N. E. Kolarik, Nawaraj Shrestha, T. Caughlin, J. S. Brandt

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Nebraska Statewide Groundwater-Level Monitoring Report 2023, Aaron R. Young, Mark E. Burbach, Sue Olafsen Lackey, Robert Matthew Joeckel, Nawaraj Shrestha, Jeffrey Westrop

Conservation and Survey Division: Faculty and Staff Publications

This report is a synthesis of groundwater-level monitoring programs in Nebraska. It is a continuation of the series of annual reports and maps produced by the Conservation and Survey Division (CSD) of the University of Nebraska in cooperation with the U.S. Geological Survey (USGS) since the 1950s. Groundwater-level monitoring began in Nebraska in 1930 to survey the state’s groundwater resources and observe changes in its availability on a regular basis. The CSD and USGS cooperatively developed, maintained, and operated an observation-well network throughout the state. These two agencies were responsible for collecting and archiving this information, and for making it …

Age Dating Young Groundwater: How To Determine Groundwater Age From Environmental Tracer Data, D. K. Solomon, T. E. Gilmore

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Unraveling Sources Of Cyanate In The Marine Environment: Insights From Cyanate Distributions And Production During The Photochemical Degradation Of Dissolved Organic Matter, Rui Wang, Jihua Liu, Yongle Xu, Li Liu, Kenneth Mopper

Chemistry & Biochemistry Faculty Publications

Cyanate is a nitrogen and energy source for diverse marine microorganisms, playing important roles in the nitrogen cycle. Despite the extensive research on cyanate utilization, the sources of this nitrogen compound remain largely enigmatic. To unravel the sources of cyanate, distributions and production of cyanate during photochemical degradation of natural dissolved organic matter (DOM) were investigated across various environments, including freshwater, estuarine, coastal areas in Florida, and the continental and slope regions of the North American mid-Atlantic Ocean (NATL). Cyanate production was also examined during the photochemical degradation of exudates from a typical strain of Synechococcus, an important phytoplankton …

Reducing The Uncertainty In Estimating Soil Microbial-Derived Carbon Storage, Han Hu, Chao Qian, Ke Xue, Rainer Georg Jörgensen, Marco Keiluweit, Chao Liang, Xuefeng Zhu, Ji Chen, Yishen Sun, Haowei Ni, Jixian Ding, Weigen Huang, Jingdong Mao, Rong-Xi Tan, Jizhong Zhou, Thomas W. Crowther, Zhi-Hua Zhou, Jiabao Zhang, Yuting Liang

Chemistry & Biochemistry Faculty Publications

Soil organic carbon (SOC) is the largest carbon pool in terrestrial ecosystems and plays a crucial role in mitigating climate change and enhancing soil productivity. Microbial-derived carbon (MDC) is the main component of the persistent SOC pool. However, current formulas used to estimate the proportional contribution of MDC are plagued by uncertainties due to limited sample sizes and the neglect of bacterial group composition effects. Here, we compiled the comprehensive global dataset and employed machine learning approaches to refine our quantitative understanding of MDC contributions to total carbon storage. Our efforts resulted in a reduction in the relative standard errors …

Potentially Massive And Global Non-Pyrogenic Production Of Condensed "Black" Carbon Through Biomass Oxidation, Aleksandar I. Goranov, Hongmei Chen, Jianshu Duan, Satish C. B. Myneni, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

With the increased occurrences of wildfires worldwide, there has been an increase in scientific interest surrounding the chemistry of fire-derived "black" carbon (BC). Traditionally, wildfire research has assumed that condensed aromatic carbon (ConAC) is exclusively produced via combustion, and thus, ConAC is equated to BC. However, the lack of correlations between ConAC in soils or rivers and wildfire history suggests that ConAC may be produced non-pyrogenically. Here, we show quantitative evidence that this occurs during the oxidation of biomass with environmentally ubiquitous hydroxyl radicals. Pine wood boards exposed to iron nails and natural weather conditions for 12 years yielded a …

Water Quality Contaminants Long-Term Spatial Analysis Along The Upper Clark Fork River Superfund Site Between Warm Springs And Garrison, Montana, Raegan Michele Osentowski

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Long-term data of heavy metal contaminants, cadmium, copper, lead, arsenic, and zinc were compiled from the Montana Department of Environmental Quality, DEQ, and the United States Geological Survey, USGS, to investigate the effects of remediation on water quality along the upper Clark Fork River superfund site. Long-term data sets were analyzed at CFR-03A, CFR-27H, CFR-34, and SS-25 along the upper Clark Fork River and Silver Bow Creek. CFR-03A and CFR-27H had full remediation in the immediate vicinity, SS-25 had on-going remediation in the immediate vicinity, and CFR-34 had no remediation in the immediate vicinity. Analysis of heavy metal contaminants is …

Groundwater Vulnerability Assessment And Dye Trace Of War Fork River In Daniel Boone National Forest, Will Hemenover

Mahurin Honors College Capstone Experience/Thesis Projects

Daniel Boone National Forest plays a key role in preserving much of Kentucky’s karst regions, natural resources including timber, mineral deposits, and biodiversity, including over 300 species of concern. The health of these environments is determined by surface and groundwater streams in the forest, and karst systems are an integral environment where these systems are active. War Fork, a tributary to the Kentucky River in Jackson County, Kentucky, is a remote and understudied hydrologic system in the Daniel Boone National Forest that contains recreational and logging land uses. Due to karst areas being susceptible to contamination because of rapid water …

Permafrost Carbon: Progress On Understanding Stocks And Fluxes Across Northern Terrestrial Ecosystems, Claire C. Treat, Anna-Maria Virkkala, Eleanor Burke, Lori Bruhwiler, Abhishek Chatterjee, Joshua B. Fisher, Josh Hashemi, Frans-Jan W. Parmentier, Brendan M. Rogers, Sebastian Westermann, Jennifer D. Watts, Elena Blanc-Betes, Matthias Fuchs, Stefan Kruse, Avni Malhotra, Kimberley Miner, Jens Strauss, Amanda Armstrong, Howard E. Epstein, Bradley Gay, Mathias Goeckede, Aram Kalhori, Dan Kou, Charles E. Miller, Susan M. Natali, Youmi Oh, Sarah Shakil, Oliver Sonnentag, Ruth K. Varner, Scott Zolkos, Edward A.G. Schuur, Gustaf Hugelius

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Significant progress in permafrost carbon science made over the past decades include the identification of vast permafrost carbon stocks, the development of new pan-Arctic permafrost maps, an increase in terrestrial measurement sites for CO₂ and methane fluxes, and important factors affecting carbon cycling, including vegetation changes, periods of soil freezing and thawing, wildfire, and other disturbance events. Process-based modeling studies now include key elements of permafrost carbon cycling and advances in statistical modeling and inverse modeling enhance understanding of permafrost region C budgets. By combining existing data syntheses and model outputs, the permafrost region is likely a wetland methane …

Soil Biogeochemistry In Riparian And Restored Tidal Wetlands: Monitoring And Method Evaluation, Joseph Anthony Loffredo

Open Access Master's Theses

Although soils are essential for sustaining ecosystems, they are often overlooked in routine monitoring efforts during restoration projects. This thesis tries to address the interest in and challenges of measuring and monitoring soil biogeochemical properties and processes to evaluate restoration trajectories. In the first part of this thesis (Chapter 1), I monitored tidal marsh vegetation and soil biogeochemical responses to restoration by thin-layer placement (TLP) of dredged sediments in a greenhouse mesocosm study and a parallel field study at an active restoration site in southern RI. In the greenhouse, aboveground plant biomass in mesocosms treated with +5 cm and +10 …

High Resolution Sedimentary Investigations Of Extant Lakes In North America, John Dilworth

Theses and Dissertations--Earth and Environmental Sciences

Investigation of past lake environments forms the discipline of paleolimnology. Paleolimnological studies seek to evaluate geophysical, geochemical, and ecological proxies and indicators contained within lake sediment archives. Using these potential stores of high-resolution environmental information, questions regarding climate, biological, and geochemical changes experienced by a lake and its watershed can be investigated. This dissertation research utilized lake sediment records from two lakes within North America to study different aspects of environmental change. This dissertation consists of three separate studies presented in three chapters.

Chapter Two presents a retrospective environmental assessment of Jackson Lake, Wyoming to investigate the impacts of dam …

Mining Contamination Of Legacy Deposits On Floodplains Along Turkey Creek, Western Border Of The Ozark Highlands, Hannah Riley Eades

Graduate Theses/Dissertations

Historical mining activities in the Tri State mining district in Southwest Missouri from 1850 to 1950 resulted in widespread metal contamination of stream sediments. Beginning in the 1840s, land disturbances associated with Euro-American settlement and agricultural expansion increased runoff and soil erosion rates resulting in the deposition of contaminated alluvium or legacy sediment on floodplains. This study assesses zinc (Zn) and lead (Pb) contaminated legacy deposits in cut-bank exposures along floodplains in Turkey Creek Watershed (119 km²) which drained mining areas in Missouri. Ore production histories were used date metal contamination profiles and calculate floodplain deposition rates in legacy deposits. …

Investigating The Roles Of Plants, Fungi, And Biocrusts In Nutrient Movement Within Dryland Ecosystems, Catherine E. Cort

Open Access Theses & Dissertations

In dryland ecosystems, plant productivity and microbial decomposition are often separated in space and time due to the asynchronous availability of soil moisture and organic matter inputs. It has been proposed that fungi play a key functional role in connecting these cycles by facilitating movement of water, carbon (C), and nitrogen (N) through a network of shared hyphae between plant roots and biological soil crust (biocrust) communities at the soil surface. This connection, also known as the â??fungal loop,â?? effectively re-couples processes of nutrient release and uptake between primary producers and minimizes ecosystem N losses due to leaching, erosion, and …

Rapid Expansion Of The Limpkin Aramus Guarauna Across Anglo-America, A. Alam, R. Kaddoura, J. Jackson, R. Kannan

Journal of the Arkansas Academy of Science

We quantitatively document and describe the recent rapid expansion of the Limpkin Aramus guarauna across Anglo-America (United States and Canada). Using data downloaded from eBird (www.eBird.org), we present graphs showing the explosive growth in reports of number of individual birds and frequencies in checklists for this species in several parts of Anglo- America outside Florida (its traditional Anglo- American range). We also provide geographic progression maps to illustrate the expansion through time (2013-2023) and furnish qualitative information on foods consumed by the bird in new areas, based on a survey of 274 images uploaded by citizen scientists in eBird. Possible …

Geographical Variation In Songs Of Bachman’S Sparrow (Peucaea Aestivalis), L. Nguyen, K. Doñas, J. Jackson, R. Kannan

Journal of the Arkansas Academy of Science

We present an analysis of geographic variation in primary song components of the Near Threatened North American endemic, Bachman’s Sparrow (Peucaea aestivalis). These songs have 2 distinct portions: an introductory tweet we call the "whistle" and a more complex second portion that we call the "trill". We analyzed 327 songs from 111 recordings downloaded from eBird.org from the entire current range of the species. We grouped the recordings into 3 distinct geographic clusters, East, Central, and West. The data measured from spectrograms suggest a significant statistical difference among groups for 3 measured characteristics: frequency range of trill, number of horizontal …

A Review Of Herpetofaunal Distributions In Arkansas With Special Emphasis On Contributions From Citizen Science: Part I – Snakes, R. Jacobs, N. Ortiz, J. Jackson, J.D. Willson, K.G. Roberts, R. Kannan

Journal of the Arkansas Academy of Science

We present a comprehensive updated review of the distributions of the 38 species of snakes in Arkansas. We compare historical and current distributions with citizen science data uploaded and verified in iNaturalist, a leading biodiversity monitoring online citizen science database. The Arkansas Herpetological Atlas, a website maintaining species occurrence records, is also used and compared. We highlight the role played by iNaturalist in enhancing our knowledge of snake distributions in Arkansas. 10,885 verified and vetted Research Grade (RG) observations of Arkansas snakes have been recorded in iNaturalist, expanding the known distributions of 36 of the 38 species. This is the …

Energy Content Of Acorns Of Shinnery Oak (Quercus Havardii) In The Diet Of Scaled Quail (Callipepla Squamata) In Southeastern New Mexico, J.L. Hunt, M.E. Grilliot, T.L. Best, D. Lozano-Lopez, E.R. Neilson, I.C. Castillo

Journal of the Arkansas Academy of Science

Shinnery oak (Quercus havardii) is a deciduous, low-growing shrubby tree that is a dominant plant in large areas of grassland in western Oklahoma, the Texas Panhandle, and eastern New Mexico. Acorns of the plant are important food items for many wildlife species, including scaled quail (Callipepla squamata), mourning doves (Zenaida macroura), and endangered lesser prairie-chickens (Tympanuchus pallidicinctus). We analyzed the energy content of acorns of shinnery oak obtained from the crops of scaled quail collected from plains-mesa sand-scrub in Lea and Eddy counties, New Mexico. Acorns were removed from crops and dried for 48 hours at 60°C to remove moisture …

Towards Machine Learning-Based Control Of Autonomous Vehicles In Solar Panel Cleaning Systems, Farima Hajiahmadi

Theses and Dissertations

This thesis presents a machine learning (ML)-based approach for the intelligent control of Autonomous Vehicles (AVs) utilized in solar panel cleaning systems, aiming to mitigate challenges arising from uncertainties, disturbances, and dynamic environments. Solar panels, predominantly situated in dedicated lands for solar energy production (e.g., agricultural solar farms), are susceptible to dust and debris accumulation, leading to diminished energy absorption. Instead of labor-intensive manual cleaning, robotic cleaners offer a viable solution. AVs equipped to transport and precisely position these cleaning robots are indispensable for efficient navigation among solar panel arrays. However, environmental obstacles (e.g., rough terrain), variations in solar panel …

Determining Hydraulic Characteristics In Close Proximity Of Hymenocallis Coronaria Within The Flint River Basin, Georgia, Sarah K. Tash

Theses and Dissertations

Emergent macrophytes in river systems occupy a narrow habitat for optimal survival. Each plant species adapts to a set of conditions that meets the physiological requirements to grow and reproduce. The influence of hydraulic characteristics on plant morphology is significant within fluvial systems. Macrophytes must be able to withstand swift flowing water and changes in water surface levels in order to compete with other plant species for limited habitat availability. In addition, emergent macrophytes require water levels to be low enough to allow the reproductive portion of plants to remain above water during certain times of the year. Hymenocallis coronaria …

Water Column Controls On Magnetic Mineral Formation And Preservation, Josephine Benson

Dartmouth College Master’s Theses

Iron-bearing minerals in the sedimentary record are frequently used to reconstruct past depositional environments. This is accomplished through geochemical, magnetic, and mineralogical analyses placed in geological context. These interpretations, however, depend on our understanding of how iron minerals form in nature. To better understand the formation of magnetic iron minerals in redox-stratified depositional settings, the study of modern analogs is crucial to unraveling environmental context no longer available from geological deposits. In this study, I utilized four anoxic and sulfidic stratified lakes within a 100-mile radius to examine the effects of small variations in lake properties on magnetic mineral formation …

A Survey Of Strongyle Nematodes In New England Dairy Goats, D.J. Richardson, E.M. Wray, D. Watters, U. Hanif, E. Jalbert, E. Thompson, G. Trajkovic, A.R. Sirois, N. Pilotte

Journal of the Arkansas Academy of Science

The paucity of information concerning the occurrence of strongyle nematodes in New England dairy goats prompted a survey of 241 dairy goats from throughout New England. Of the 241 goats examined using the McMaster technique, 104 (42.7%) were infected with strongyles with a mean intensity (+ SE) of 369.7 + 45.8 eggs per gram. Subsequent molecular examination of 50 random samples from these goats revealed a prevalence of 88% infection specifically with Haemonchus contortus. Haemonchus contortus is the most important internal parasite of sheep and goats, exerting a crushing economic burden on the livestock industry worldwide due to lowered milk …

Evaluating The Risk Posed By Gadolinium In The Grand River Watershed, Johann Memmel

Theses and Dissertations (Comprehensive)

Gadolinium (Gd) is a rare earth element (REE), primarily used in contrast agents for magnetic resonance imaging (MRI), with additional applications in metallurgy, phosphors, neutron shielding, and other niche applications. Both Gd and Gd-based contrast agents (GBCAs, the form used for MRIs) have been detected downstream of wastewater effluent discharges and there is currently little research into the risk this poses to aquatic ecosystems. This study investigated the potential environmental risks of Gd and GBCAs using the Grand River watershed (GRW) in southwestern Ontario as a model ecosystem due to it containing a variety of land uses (urban, industrial, agricultural) …

Assessing Stormwater Management Pond Water Quality, Function, And The Potential Biotic Effects To Receiving Waters, Mitchell Elstone

Theses and Dissertations (Comprehensive)

The use of stormwater management ponds (SWMPs) has been increasing over the past five decades. However, an in-depth understanding of the daily performance of SWMPs and functionality during cold periods is limited. This is in part because mandated monitoring is relatively infrequent, and the assumption that SWMPs are inactive between storm events and during the winter. The goals of this research were to better understand daily stormwater (SW) characteristics, the performance of SWMPs based on current forms of evaluation and assess the potential for SWMP effluent to impact downstream biota. Influent and effluent samples from two SWMPs were collected daily …

Distal Urogenital Anatomy And Epithelial Morphology In The Male Cajun Chorus Frog, Pseudacris Fouquettei (Anura: Hylidae), S.E. Trauth

Journal of the Arkansas Academy of Science

I examined the microanatomy of the distal urogenital system in male Cajun Chorus Frogs (Pseudacris fouquettei) from a small sample (n = 6) collected in central Arkansas in March 2018 and February 2023. Specifically, my primary objectives were to investigate the following: (1) the paired Wolffian (urogenital) ducts caudally from the kidneys to their merging with the urodeum of the cloaca, (2) the structure of seminal vesicles (if present), and (3) the epithelial morphologies among the distal urogenital tract, the posterior alimentary canal, and cloaca. My histological analysis confirmed the presence of ampullae (sperm storage structures) as mid-duct expansions of …

Use Of Google Earth Streetview To Evaluate Nesting By The Cliff Swallow (Petrochelidon Pyrrhonota) In Lowlands Of Eastern Arkansas, With Reports Of New Records, R. Tumlison, Z. Autrey

Journal of the Arkansas Academy of Science

Cliff Swallows (Petrochelidon pyrrhonota) typically construct their mud nests under the overhangs of cliffs. However, construction of concrete bridges and overpasses has provided suitable nesting structure in the last few decades. As the number of such nesting sites have increased, the breeding range also has expanded. We evaluated the use of Google Earth Streetview as a means of cheaply harvesting data regarding nesting distribution. The gourd-shaped nests of Cliff Swallows were easily discernible via available imagery, and we were able to document previously unreported nest sites of this species in 6 counties in eastern Arkansas (5 from imagery, 1 from …