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Articles 4681 - 4710 of 59392
Full-Text Articles in Entire DC Network
Evidence Of Mineral Alteration In A Salt Marsh Subterranean Estuary: Implications For Carbon And Trace Element Cycling, J. J. Tamborski, M. J. Eagle, M. T. Thorpe, M. A. Charette, B. L. Kurylyk, S. Rahman, K. D. Kroeger, J. O'Keefe Suttles, A. G. Mann, T. W. Brooks, Z. A. Wang
Evidence Of Mineral Alteration In A Salt Marsh Subterranean Estuary: Implications For Carbon And Trace Element Cycling, J. J. Tamborski, M. J. Eagle, M. T. Thorpe, M. A. Charette, B. L. Kurylyk, S. Rahman, K. D. Kroeger, J. O'Keefe Suttles, A. G. Mann, T. W. Brooks, Z. A. Wang
OES Faculty Publications
Subterranean estuaries (STE) in salt marshes are biogeochemically active zones where interactions between terrestrial groundwater and seawater drive complex cycling of carbon and trace elements, influenced by mineral dissolution. These systems, characterized by fine-grained organic-rich peat overlying permeable coastal aquifers, play a crucial role as a blue carbon sink, yet their geochemical dynamics remain poorly understood. We investigated dissolved trace elements, carbon, silica, and radium isotopes in a salt marsh STE (Sage Lot Pond, Waquoit Bay, MA) over seasonal and annual cycles. Our results reveal that groundwater and estuarine water circulation through marsh peat and aquifer sediments leads to enrichments …
Spatial Analysis Of American Chestnut (Castanea Dentata) Distribution And Ecology In Kentucky’S Federal Lands, Jacob Raymond Pease
Spatial Analysis Of American Chestnut (Castanea Dentata) Distribution And Ecology In Kentucky’S Federal Lands, Jacob Raymond Pease
Murray State Theses and Dissertations
Anthropogenic factors have been the cause of the decline of tree species across the globe. From unsustainable logging and development to disease and improper management, threats to forests have taken their toll. The American chestnut (Castanea dentata) was once an integral basal tree species in Appalachian forests, but chestnut blight drove the species to functional extinction by the mid-1900s. The recent creation of genetically modified chestnuts gives hope for future restoration of the species throughout its historical range. Despite blight resistance, effective restoration will require optimal site selection for finding and planting chestnuts, which will maximize limited resources. …
A Hybrid Method For Source Direction Finding With Radio Frequency Interference And Gaussian White Noise, Yanming Zhang, Wenchao Xu, Antonios Argyriou, A. Long Jin, Tianquan Tang, Peifeng Ma, Lijun Jiang, Steven Gao
A Hybrid Method For Source Direction Finding With Radio Frequency Interference And Gaussian White Noise, Yanming Zhang, Wenchao Xu, Antonios Argyriou, A. Long Jin, Tianquan Tang, Peifeng Ma, Lijun Jiang, Steven Gao
Electrical and Computer Engineering Faculty Research & Creative Works
This paper presents a hybrid data-driven method, termed moving average-Hankel-dynamic mode decomposition (MAHankDMD), for joint direction of arrival (DOA) and frequency estimation in environments affected by both radio frequency interference (RFI) and Gaussian white noise. The proposed approach integrates two key components: (1) a moving average-DMD filter that effectively mitigates Gaussian white noise and separates RFI from the source signal, and (2) a Hankel-DMD method that accurately estimates the DOA of the filtered signal and associates it with the corresponding frequency. The moving average-DMD stage first enhances the signal-to-noise ratio and improves the robustness of the estimation process through noise …
Igc Oral Presentation Summary: Xxv Igc Congress, S. Ray Smith, Echo Elizabeth Gotsick, J. R. Weinert-Nelson, Alayna Jacobs, Christopher D. Teutsch, Will Fleming, D. R. Woodfield, James L. Klotz, Jeff Lehmkuhler, Greg S. Halich, Brittany Davis, Brittany Hendrix, Krista Lea
Igc Oral Presentation Summary: Xxv Igc Congress, S. Ray Smith, Echo Elizabeth Gotsick, J. R. Weinert-Nelson, Alayna Jacobs, Christopher D. Teutsch, Will Fleming, D. R. Woodfield, James L. Klotz, Jeff Lehmkuhler, Greg S. Halich, Brittany Davis, Brittany Hendrix, Krista Lea
IGC Proceedings (1977-2023)
This paper will give an overview of the XXV International Grassland Congress thematic, keynote, and plenary sessions. The theme of the XXV IGC Congress meeting was “Grasslands for Soil, Animal, and Human Health.” We had many people attending, presenting, and participating in all these sessions. Within a month after the conclusion of the Congress, the proceeding’s papers presented at the meeting will be available on the IGC app. By the end of 2023 all papers will be available for download through any search engine at internationalgrasslands.org.
Spatiotemporal Economic Impact Analysis Of The Taal Volcano Eruption Using Electricity Consumption And Nighttime Light Data, Ma Flordeliza P. Del Castillo, Toshio Fujimi, Hirokazu Tatano
Spatiotemporal Economic Impact Analysis Of The Taal Volcano Eruption Using Electricity Consumption And Nighttime Light Data, Ma Flordeliza P. Del Castillo, Toshio Fujimi, Hirokazu Tatano
SOSE Affiliate: Manila Observatory
Analyzing the spatiotemporal dimension of the economic impacts of disasters is critical for providing timely and proportionate support. However, traditional economic impact measures often lack spatiotemporal details. Hence, we estimated the daily electricity consumption (EC) loss using high-frequency EC data and analyzed temporal dimensions of the immediate impacts of Taal Volcano’s eruption on January 12, 2020. Subsequently, we computed the nighttime light (NTL) change using high-resolution NTL data to analyze the spatial distribution of these impacts. The temporal analysis revealed two EC loss peaks. The first peak coincided with the power outage and decreased energy demand, followed by a brief …
Topographic Forcing Of Submesoscale Instability In The Antarctic Circumpolar Current, Laur Ferris, Donglai Gong, John Klinck
Topographic Forcing Of Submesoscale Instability In The Antarctic Circumpolar Current, Laur Ferris, Donglai Gong, John Klinck
CCPO Publications
Subpolar frontal zones are characterized by energetic storms, intense seasonal cycles, and close connectivity with surrounding continental shelf topography. At the same time, predicting the ocean state depends on appropriate partition of resolved and parameterized dynamics, the latter of which requires understanding the dynamical processes generating diffusivity throughout the water column. While submesoscale frontal instabilities are shown to produce turbulent kinetic energy (TKE) and mixing in the surface boundary layer (SBL) of the global ocean, their development in complex dynamical regimes (e.g., elevated preexisting turbulence, large ageostrophic shear, or in proximity to topographic boundaries) is less understood. This study investigates …
Estimation Of Burned Severity Areas Using Landsat8 Data From 2016 To 2022 In Chiang Mai Province, Sarunya Karuna
Estimation Of Burned Severity Areas Using Landsat8 Data From 2016 To 2022 In Chiang Mai Province, Sarunya Karuna
Chulalongkorn University Theses and Dissertations (Chula ETD)
This study aims to evaluate the area and severity of wildfire damage in Chiang Mai Province using LANDSAT8 satellite data from 2016, 2018, 2020, and 2022, and to analyze the relationship between spatial factors, namely the Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST), with fire occurrence and severity. The study utilized hotspot data analysis in conjunction with the Differenced Normalized Burn Ratio (dNBR) index to assess the area and classify fire severity levels, while also analyzing pre-fire and post-fire NDVI and LST values to identify correlations. The results indicated that 2020 experienced the most severe fire situation, …
Heat Treatment Of Basaltic-Related Sapphire From Binh Thuan Deposit, Southern Vietnam, Yuparat Kwangsawat
Heat Treatment Of Basaltic-Related Sapphire From Binh Thuan Deposit, Southern Vietnam, Yuparat Kwangsawat
Chulalongkorn University Theses and Dissertations (Chula ETD)
Characteristics of basalt-related sapphires from Binh Thuan in Southern Vietnam were investigated before and after heat treatment. Samples were divided into four group, based on their color and hue including dark blue, blue, greenish blue, and bluish green. After being heated at 700-1000°C, sapphires' blue hue faded noticeably. Blue color turned to be intensified when heated at 1650°C. Subsequently, beryllium-assisted heating by a local professional gem treater was introduced to these sapphire samples which in turn yielded yellow to yellowish-blue hues. Color changes after heating are conclusively involved by trace compositions of sapphire and temperatures of heating. The appropriate treatment …
การศึกษารูปแบบความร่วมมือของภาครัฐและภาคเอกชนในการบริหารจัดการเหตุวิกฤติฉุกเฉินและนโยบายการรักษาความปลอดภัยย่านศูนย์กลางธุรกิจของกรุงเทพมหานคร, ปัญจรัตน์ เดชกุญชร
การศึกษารูปแบบความร่วมมือของภาครัฐและภาคเอกชนในการบริหารจัดการเหตุวิกฤติฉุกเฉินและนโยบายการรักษาความปลอดภัยย่านศูนย์กลางธุรกิจของกรุงเทพมหานคร, ปัญจรัตน์ เดชกุญชร
Chulalongkorn University Theses and Dissertations (Chula ETD)
ภัยพิบัติเป็นสิ่งที่ทั่วโลกเล็งเห็นความสำคัญและให้ความตระหนักในการบริหารจัดการ ด้วยการเปลี่ยนแปลงของโลกเป็นปัจจัยกระตุ้นให้เกิดเหตุขึ้นบ่อยครั้ง เป็นเหตุวิกฤติที่เกินการรับมือ การศึกษาเรื่อง รูปแบบความร่วมมือของภาครัฐและภาคเอกชนในการบริหารจัดการเหตุวิกฤติฉุกเฉินและนโยบายการรักษาความปลอดภัยย่านศูนย์กลางธุรกิจของกรุงเทพมหานคร เป็นการศึกษาในภาคการขับเคลื่อนนโยบายการบริหารระหว่างหน่วยงานภาครัฐและเครือข่ายภาคประชาชนในพื้นที่ย่านราชประสงค์ เขตปทุมวัน ภายใต้กรอบแนวคิดการร่วมมือทำงานกันระหว่างภาครัฐและภาคเอกชนแบบเครือข่าย Networking มีวัตถุประสงค์เพื่อทราบถึง 1) รูปแบบความร่วมมือเชิงนโยบายของภาครัฐและภาคเอกชนในการบริหารจัดการเหตุวิกฤติ 2) นโยบายการรักษาความปลอดภัยของภาครัฐและภาคเอกชนในพื้นที่ย่านราชประสงค์ 3) การออกแบบแผนการรับมือเหตุวิกฤติ และ 4) เพื่อดูแนวโน้มการเป็นต้นแบบนำร่องไปใช้ในพื้นที่ชุมชนเมืองอื่นในกรุงเทพมหานคร เป็นการวิจัยเชิงคุณภาพแบบกรณีศึกษา โดยการสัมภาษณ์ผู้บริหารกลุ่มภาคเอกชนกลุ่มผู้ประกอบวิสาหกิจในย่านราชประสงค์ จำนวน 10 องค์กร และหน่วยงานภาครัฐในพื้นที่อีก 2 องค์กร ใช้แบบสัมภาษณ์กึ่งโครงสร้าง วิเคราะห์ข้อมูลเชิงเนื้อหา พรรณนา พัฒนาแก่นสาระ ตรวจสอบด้วยวิธีเทคนิคสามเส้า ร่วมกับการศึกจากข้อมูลเอกสารและการลงพื้นที่เพื่อสังเกตการณ์ ผลการวิจัยพบว่า (1) รูปแบบความร่วมมือเชิงนโยบายของภาครัฐและภาคเอกชนในการบริหารจัดการเหตุวิกฤติฉุกเฉินในย่านราชประสงค์ ขับเคลื่อนด้วยแนวคิดการจัดการปกครองสาธารณะแนวใหม่แบบเครือข่าย ระหว่างภาครัฐกับเครือข่ายภาคเอกชน บวกกับ Disaster Management และ Crisis Management (2) นโยบายการรักษาความปลอดภัยใช้การร่วมออกแบบ ร่วมคิด และขับเคลื่อนกลไกเชิงนโยบายมีปฏิสัมพันธ์ในระดับองค์กร และระดับบุคคลต่อบุคคล (3) การออกแบบแผนการรับมือเหตุวิกฤติฉุกเฉินจากภัยพิบัติในย่านราชประสงค์ ใช้วิธีการเตรียมความพร้อม ตามหลักการของ Disaster Management ร่วมกับ Crisis Management (4) แนวโน้มการเป็นต้นแบบนำไปใช้ในพื้นที่ชุมชนเมืองอื่นในกรุงเทพมหานคร ต้องพิจารณาร่วมด้วยกับความเข้มแข็งของความร่วมมือของรัฐและเอกชนที่มีวิสัยทัศน์ แนวทางในการขับเคลื่อนไปในทิศทางเดียวกัน ระบบการเงินส่วนกลางที่น่าเชื่อถือ มีการจัดปรับการใช้รูปแบบให้เหมาะสมกับทรัพยากรที่มีอยู่ในพื้นที่ของตนเอง
Early Holocene Interaction Of Aeolian, Alluvial, And Lacustrine Processes In A Dune-Dammed Valley In The Central Nebraska Sand Hills, Gpsia Mahoney, R. D. Mandel, P.R. Hanson, Sherilyn Fritz
Early Holocene Interaction Of Aeolian, Alluvial, And Lacustrine Processes In A Dune-Dammed Valley In The Central Nebraska Sand Hills, Gpsia Mahoney, R. D. Mandel, P.R. Hanson, Sherilyn Fritz
Conservation and Survey Division: Faculty and Staff Publications
No abstract provided.
Distribution And Tooth Morphoguilds Of Mosasaurids (Squamata) Of The Campanian Western Interior Seaway With Implications For Controls On Mosasaur Paleobiogeography, Alec Zaborniak
Master's Theses or Doctor of Nursing Practice
The Western Interior Seaway (WIS) of North America is well known for its mosasaurid squamate diversity, particularly during the Campanian of the Late Cretaceous. Mosasaurid diversity has historically been examined at a fine scale, with many studies investigating the faunal composition of specific assemblages; however, studies focusing on mosasaur communities within the Western Interior Seaway during specific Ages are currently lacking. Mosasaur tooth morphology has also been extensively studied, with tooth characteristics commonly being used as phylogenetic characters. However, many studies examining mosasaur communities and tooth morphology have been focused on broader spatiotemporal or phylogenetic scales. This study investigates the …
The Effects Of Return To Prairie In Barber County, Kansas: A Case Study Using Ndvi And Dendrochronology, Elijah O. Joy
The Effects Of Return To Prairie In Barber County, Kansas: A Case Study Using Ndvi And Dendrochronology, Elijah O. Joy
Master's Theses or Doctor of Nursing Practice
This study aims to evaluate the impact of prairie restoration efforts in Barber County, Kansas, with a focus on removal of Eastern Red Cedar. Restoration effectiveness was assessed using remote sensing of satellite scenes via NDVI, density analysis, and dendrochronological methods. The tree density analysis revealed a 66% reduction across the study area and a 99% reduction in the fully restored zones. NDVI analysis from 2010 to 2024 showed higher summer vegetation health and seasonal fluctuations influenced by climate variability and fire events. Dendrochronological data from tree cores reveals growth patterns and establishes a baseline for future dendrochronological chronologies. The …
Oil-Oil Correlation Across Sedimentary Basins In Kansas Using Molecular Geochemistry And Fourier Transform Infrared Spectroscopy, Oluwaseun V. Omoyemi
Oil-Oil Correlation Across Sedimentary Basins In Kansas Using Molecular Geochemistry And Fourier Transform Infrared Spectroscopy, Oluwaseun V. Omoyemi
Master's Theses or Doctor of Nursing Practice
Hydrocarbons are produced from different subbasins and stratigraphic intervals in Kansas. However, the geochemical characteristics and sources of these hydrocarbons are still poorly understood. While reservoir rocks, seals, and traps that are essential for petroleum systems are well defined within the state, the possible source rocks are often considered thermally immature, raising questions about their ability to generate the volume of hydrocarbons currently being produced. This research project tries to evaluate the geochemical characteristics of hydrocarbons produced in the state of Kansas and determine if the hydrocarbons from the different subbasins and stratigraphic units are genetically related. Thirty-seven crude oil …
A Histological Survey Of A Large, Sub-Adult Tylosaurus Nepaeolicus With Implications On The Validity Of Tylosaurus Kansasensis, Carson Cope
Master's Theses or Doctor of Nursing Practice
Tylosaurus nepaeolicus is a basal, medium-sized tylosaurine mosasaur that lived during the late Coniacian and early Santonian in the Western Interior Seaway. Despite being a well-studied species, there is debate over whether Tylosaurus kansasensis represents the juvenile form of T. nepaeolicus, or if the two species are distinct. Osteohistology can determine organism age at time of death and can be used to help resolve this debate and provide a better understanding of the growth of T. nepaeolicus. Thin-sections were taken from a humerus, rib, and vertebra of a single individual (FHSM VP-2209). All thin-sections show primarily parallel-fibered cortical …
Applying Transfer Learning For Street-Scale Nuisance Flood Forecasting In Coastal-Urban Cities, Binata Roy, Jonathan L. Goodall, Diana Mcspadden, Chetan Kumar, Steven Goldenberg, Yidi Wang, Malachi Schram
Applying Transfer Learning For Street-Scale Nuisance Flood Forecasting In Coastal-Urban Cities, Binata Roy, Jonathan L. Goodall, Diana Mcspadden, Chetan Kumar, Steven Goldenberg, Yidi Wang, Malachi Schram
VMASC Publications
An important challenge with Machine Learning (ML) is its transferability; i.e., whether a ML model trained on one set of data can be applied to a second set of data without requiring full re-training of the model. Transfer Learning (TL) addresses this challenge by transferring knowledge learned in the source domain (the data it was trained on) to the target domain (a second set of data that is statistically different but related, which the model was not trained on). This study investigates the use of TL for street-scale nuisance flood forecasting by exploring whether a ML model trained for one …
Moderate Heating Renders 7.8-Million-Year-Old Sedimentary Organic Matter Bioavailable, Shuchai Gan, Verena B. Heuer, Frauke Schmidt, Lars Wormer, Faming Wang, Rishi R. Adhikari, Patrick Hatcher, Ann Pearson, Kai-Uwe Hinrichs
Moderate Heating Renders 7.8-Million-Year-Old Sedimentary Organic Matter Bioavailable, Shuchai Gan, Verena B. Heuer, Frauke Schmidt, Lars Wormer, Faming Wang, Rishi R. Adhikari, Patrick Hatcher, Ann Pearson, Kai-Uwe Hinrichs
Chemistry & Biochemistry Faculty Publications
Marine sediments are a large reservoir of recalcitrant organic matter and host microbes at subsurface depths exceeding 2.4 kilometers and temperatures up to 120°C, yet the mechanisms supplying bioavailable substrates remain unclear. Here, we investigated 7.8-million-year-old sediment from IODP Site C0012 off the Nankai Trough, Japan, through incubations at 20°, 35°, 55°, and 85°C to simulate burial temperatures. Using 3D fluorescence spectroscopy and ultrahigh-resolution mass spectrometry, we tracked changes in dissolved organic matter (DOM). At 35°C, humic-like DOM was released alongside metal ions, exhibiting low bioavailability. At 55°C, abiotic decomposition of humic compounds generated smaller, more bioavailable DOM, promoting fermentation. …
Molecular Characterization Of Humic And Fulvic Acids On Watterlogged And Well-Drained Amazonian Podzols, Amanda M. Tadini, Aleksandar I. Goranov, Stéphane Mounier, Débora M.B.P. Milori, Célia R. Montes, Patrick G. Hatcher
Molecular Characterization Of Humic And Fulvic Acids On Watterlogged And Well-Drained Amazonian Podzols, Amanda M. Tadini, Aleksandar I. Goranov, Stéphane Mounier, Débora M.B.P. Milori, Célia R. Montes, Patrick G. Hatcher
Chemistry & Biochemistry Faculty Publications
The Amazon rainforest is the largest tropical rainforest in the world. Amazonian Podzol soils, characteristic of this region, are known to store substantial amounts of organic carbon in both their surface and deep horizons. Despite decades of research, the molecular-level composition of these soils remains uncharacterized. This study addresses this knowledge gap by employing ultrahigh resolution mass spectrometry, namely, Fourier transform–ion cyclotron resonance–mass spectrometry (FT-ICR-MS), to determine the molecular composition of humic acid (HA) and fulvic acid (FA) fractions from two Amazonian Podzol profiles of varying levels of groundwater exposure (waterlogged vs well-drained). In the waterlogged soil compounds containing nitrogen, …
Deciphering The Chemistry Of Condensed Aromatic "Black" Carbon And Nitrogen In Amazonian Anthrosols, João Vitor Dos Santos, Aleksandar I. Goranov, Laís G. Fregolente, Marcia C. Bisinoti, Zhenhuan Sun, Klaus Schmidt-Rohr, Patrick G. Hatcher
Deciphering The Chemistry Of Condensed Aromatic "Black" Carbon And Nitrogen In Amazonian Anthrosols, João Vitor Dos Santos, Aleksandar I. Goranov, Laís G. Fregolente, Marcia C. Bisinoti, Zhenhuan Sun, Klaus Schmidt-Rohr, Patrick G. Hatcher
Chemistry & Biochemistry Faculty Publications
Amazonian anthrosols are renowned for their high fertility and dark color, properties primarily attributed to the abundance of condensed aromatic carbon (ConAC) in the soil organic matter. ConAC, commonly referred to as black carbon, play a key role in the stability and nutrient retention of these soils. However, the processes governing the formation of ConAC and its transformation into oxygenated derivatives remain poorly understood. In this study, we used multiple analytical platforms to investigate the chemistry of ConAC-rich humic acids (HA) extracted from Terra Mulata de Indio, a type of Amazonian anthrosol. The results reveal that ConAC are predominantly …
Oxidation Camouflages Terrestrial Organic Matter To Appear Marine-Like, Aleksandar I. Goranov, Susan J. Carter, Ann Pearson, Patrick G. Hatcher
Oxidation Camouflages Terrestrial Organic Matter To Appear Marine-Like, Aleksandar I. Goranov, Susan J. Carter, Ann Pearson, Patrick G. Hatcher
Chemistry & Biochemistry Faculty Publications
The export of terrestrial organic matter (TOM) to the ocean has been traditionally viewed to be minimal or only of significance in near-coastal continental margins. The broadly accepted explanation for the widespread loss of terrestrial lignin biomarkers and apparent disappearance of the <-25‰ stable carbon isotopic signature (δ¹³C) of TOM is that TOM is almost fully degraded before reaching the open ocean. Oceanic carbon (δ¹³C value ≥ -22‰) is therefore thought to be derived primarily from algae. However, an alternative explanation for the different molecular and δ¹³C signatures in terrestrial and marine environments may be that oxidative processing transforms TOM to appear marine-like. To test this hypothesis, we subjected eight TOM samples to a strong oxidation gradient. At carbon losses typical of TOM degradation during transport and sedimentation (above 60%), the differentiators of provenance disappeared, leaving a residue that was marine-like both chemically (aliphatic- and nitrogen-rich) and isotopically (δ¹³C enrichment of 4 to 9‰). This challenges the validity of conventional two-endmember mixing models, suggesting that a much larger fraction than previously estimated of the organic matter found in the ocean may originate from terrestrial sources, impacting global models of carbon cycling and sequestration.
Restoring Rattlesnake Creek: Using Citizen Science To Assess The Ecological And Morphological Impacts Of Dam Removal In Western Montana, Bethany Blakey
Restoring Rattlesnake Creek: Using Citizen Science To Assess The Ecological And Morphological Impacts Of Dam Removal In Western Montana, Bethany Blakey
Undergraduate Theses, Professional Papers, and Capstone Artifacts
As dam removals increase in frequency across the U.S., most research has focused on the impact of larger dam removals, despite the removal of small dams being much more common. Given the hundreds of small dams in Montana, this research uses citizen science data collected over eight years spanning before and after a 2020 small dam removal in Rattlesnake Creek, Montana, to investigate impact on stream ecology and morphology. We analyzed pebble count grain size distributions and aquatic macroinvertebrate biotic indices from 2017 to 2024 to assess changes in sediment transport and macroinvertebrate population as well as evaluate the efficacy …
Exploring Nitrate Reduction In A Saturated Riparian Buffer Through A Three-Dimensional Reactive Contaminant Transport Model In An Agricultural Area, Mcclean County Central Illinois, Franklin O. Ijigade
Exploring Nitrate Reduction In A Saturated Riparian Buffer Through A Three-Dimensional Reactive Contaminant Transport Model In An Agricultural Area, Mcclean County Central Illinois, Franklin O. Ijigade
Theses and Dissertations
Saturated Riparian Buffers (SRBs) are engineered systems designed to remove nitrate and other pollutants from subsurface agricultural drainage water before it reaches a stream. This study utilizes a high-resolution coupled flow and reactive transport model to explore nitrate reduction and transformation in an SRB in glacial sediment. The influence of material heterogeneity on nitrate reduction and the effectiveness of the SRB was investigated. The study was conducted in an SRB located next to and receiving tile drainage water that ultimately drains into a 3rd order stream (T3 stream) in central Illinois, USA. A three-dimensional steady groundwater flow model was …
Application Of Floating Wetlands To Improve Urban Stream Quality, Daniel Chukwunonso Chukwudi
Application Of Floating Wetlands To Improve Urban Stream Quality, Daniel Chukwunonso Chukwudi
Theses and Dissertations
Urban streams, impacted by urbanization, often exhibit degraded water quality due to elevated nutrient levels, a phenomenon known as urban stream syndrome. This study evaluates the effectiveness of a floating wetland (FW) system in reducing nitrate as nitrogen (NO₃-N) and phosphate (PO₄³⁻) concentrations in a side canal of the Chicago River’s North Branch, adjacent to Goose Island, Chicago, IL, from 2018 to 2023. Using a five-year dataset, including new sampling from May to December 2023, the research addresses two questions: (1) Do FWs lower NO₃-N and PO₄³⁻ concentrations in urban streams? and (2) Do FWs exhibit seasonal differences in nutrient …
Geochemical And Sedimentological Signals Of Bottom Water Oxygen Dynamics From Lake Tanganyika (Zambia), Njahi Mwangala
Geochemical And Sedimentological Signals Of Bottom Water Oxygen Dynamics From Lake Tanganyika (Zambia), Njahi Mwangala
Theses and Dissertations--Earth and Environmental Sciences
Lake Tanganyika is a large, ancient freshwater body with exceptional biodiversity that is located in the East African Rift System. Lake Tanganyika’s size and longevity make its sedimentary record useful for understanding environmental changes that cross spatial and temporal boundaries. Lake Tanganyika is known to be susceptible to global warming given its tropical location. Over 12 million people living within Lake Tanganyika’s watershed rely on fishing for their income and nutrition. Changes to limnological function driven by climate could therefore have serious implications for human health and biodiversity conservation. This study focuses on using geochemical properties of modern lake bottom …
Late Holocene Paleolimnology Of Lake Tanganyika (East Africa), Leandro Domingos Luz
Late Holocene Paleolimnology Of Lake Tanganyika (East Africa), Leandro Domingos Luz
Theses and Dissertations--Earth and Environmental Sciences
Understanding the long-term responses of ecosystems to climate variability is crucial for predicting and mitigating future changes in the Afrotropics, a region where a significant portion of the population is highly vulnerable to extreme climatic events. Lake Tanganyika, the largest rift lake in East Africa, offers a unique sedimentary archive that can be used to investigate the limnological changes, hydroclimatic shifts, and vegetation dynamics across various timescales. A multi-proxy approach was employed to assess the landscape responses to hydroclimatic fluctuations in the Late Holocene, integrating paleoenvironmental records from radiocarbon-dated sediment cores. This approach involved sedimentology, mineralogy, geochemistry, phytolith analysis, and …
Applications Of Remote Sensing Data To Understanding Geohazards In Wyoming And Kentucky, Meredith Swallom
Applications Of Remote Sensing Data To Understanding Geohazards In Wyoming And Kentucky, Meredith Swallom
Theses and Dissertations--Earth and Environmental Sciences
Shallow geohazards such as earthquakes, landslides, and floods profoundly impact communities globally. Constraining susceptibility to these hazards is critical for effective hazard mitigation and building more resilient communities. This dissertation includes multiple studies that leverage remotely sensed datasets to address hazard susceptibility, including: (1) characterizing a potential northern extension of the Teton fault system, (2) deriving a vegetation-based metric to improve landslide susceptibility maps in eastern Kentucky, with potential global implications, and (3) combining numerical modeling, landscape models, and field constraints to understand how anthropogenic factors affect flood severity in southern Appalachian catchments.
In the first study, analysis of new …
Multi-Scale Analysis Of Karst Aquifer Vulnerability To Climate Change And Contamination Processes, Shishir Sarker
Multi-Scale Analysis Of Karst Aquifer Vulnerability To Climate Change And Contamination Processes, Shishir Sarker
Theses and Dissertations--Earth and Environmental Sciences
Karst aquifers represent some of the world’s most productive yet vulnerable groundwater systems, supplying freshwater to approximately 10% of the global population across 15% of Earth’s ice-free land surface. Their distinctive hydrological characteristics— including rapid recharge, preferential flow paths, and limited natural filtration— create unique vulnerabilities to both climate variability and contamination that pose significant challenges for sustainable water resource management. This dissertation presents a comprehensive multi-scale analysis of karst aquifer vulnerability through three interconnected studies that examine climate change impacts, microbial contamination dynamics, and contaminant transport processes across diverse geographic and hydrogeologic settings.
Chapter two investigates climate change impacts …
Monazite Ages In And Fertility Of Crystalline Basement Rocks Of The Eastern Inner Piedmont Province: Potential Source Of Detrital Ree Critical Mineral Resources In The Coastal Plain And Modern Fluvial Systems, Abagale K. Ramsey
Theses and Dissertations--Earth and Environmental Sciences
The southeastern United States has been known for over a century as a potential resource for rare earth elements due to the abundance of monazite in sediments and crystalline basement rocks. However, sedimentary evolution of the monazite from bedrock to placer deposit and the provenance of the monazite remain untested. This study examined samples collected from the basement rocks of the Piedmont terrane in South Carolina and western North Carolina including peraluminous granites, metagranites, mica schists, and biotite gneisses, and heavy-mineral concentrates of first-order streams draining from these rocks, for age comparison and monazite abundance. Monazite grains were analyzed for …
Geochronologic Constraints On The Meso-Neoproterozoic Tectonic Evolution Of Eastern Laurentia: An Investigation Of Sediment Recycling During And After The Grenvillian Orogeny, John M. Clay Iii
Theses and Dissertations--Earth and Environmental Sciences
The Grenvillian orogeny and Midcontinent Rift shaped the Mesoproterozoic basement of eastern Laurentia. Their convergence beneath Kentucky and Ohio formed a foreland basin, preserved as the Middle Run Formation. Detrital zircon U-Pb geochronology constrains deposition to ~1.0 Ga, reflects Grenville unroofing phases, includes Midcontinent Rift input, and minor Ottawan components. This formation constitutes the most proximal preserved segment of the Grenvillian clastic wedge in Laurentia.
Neoproterozoic-Cambrian rifting followed by Cambrian transgression formed the Great Unconformity in eastern Laurentia. Detrital zircon and basement U-Pb ages from Kentucky and the Appalachians constrain sediment provenance and recycling. Kentucky basement shows Eastern Granite-Rhyolite crust …
Chemical Compositions Of Initial And Residual Silicate Source Glasses From Degassing Experiments: Implications For Mars, Natalie Zimmermann
Chemical Compositions Of Initial And Residual Silicate Source Glasses From Degassing Experiments: Implications For Mars, Natalie Zimmermann
Geosciences Research Data
These files contain supporting data for the JGR manuscript Trace Element Transport and Deposition during Magmatic Degassing: The Effect on Martian Rocks and Fines. They report the chemical compositions (major oxides and volatiles) of initial and residual silicate source glasses from degassing and vapor-transport experiments. Composition (wt%) of major oxides calculated from EMPA (renormalized on a volatile-free basis); Cl and SO2 from EMPA (wt% based on total of oxides+Cl+SO2); wt% H2O calculated from micro-FTIR. Files include the raw EMPA and FTIR data, processing, and calculations used to obtain the chemical compositions presented in Table 5 of the manuscript.
Sem Images And Eds Spectra Of Vapor Deposited Phases, Natalie Zimmermann
Sem Images And Eds Spectra Of Vapor Deposited Phases, Natalie Zimmermann
Geosciences Research Data
This file contains supplemental data for the JGR manuscript Trace Element Transport and Deposition during Magmatic Degassing: The Effect on Martian Rocks and Fines (Zimmermann et al., in review). It includes SEM images and associated EDS spectra of vapor deposited phases produced in experiments.