Open Access. Powered by Scholars. Published by Universities.®

2019

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 211 - 240 of 674

Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology

Changes In Mammalian Abundance Through The Eocene–Oligocene Climate Transition In The White River Group Of Nebraska, Usa, Robert Gillham Jul 2019

Changes In Mammalian Abundance Through The Eocene–Oligocene Climate Transition In The White River Group Of Nebraska, Usa, Robert Gillham

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Marine records show major cooling during the Eocene-Oligocene Climate Transition (EOCT). Most proxy studies in the White River Group suggest drying across the EOCT, and some suggest cooling. The lower resolution continental record has hindered a direct correlation of the marine climate record to Nebraska. I explore various correlation schemes and what they imply for faunal changes. This study compiles and analyzes data from 4,875 specimens in the University of Nebraska State Museum (UNSM) collection to test the hypothesis that climate change across the Eocene-Oligocene (E-O) boundary caused significant abundance changes in mammals. A series of binning schemes was created. …


Reconstruction Of Northeastern Pacific Ocean Holocene Production Using Marine Mammal Archaeofauna, Andrea M. Traffichini Jul 2019

Reconstruction Of Northeastern Pacific Ocean Holocene Production Using Marine Mammal Archaeofauna, Andrea M. Traffichini

HCNSO Student Theses and Dissertations

Changes in marine production play a key role in determining the trophic structure of the northeastern Pacific Ocean. This is a region of great environmental fluctuations due to modern, historical, and paleo-environmental variability recorded throughout the Holocene. These fluctuations are recorded in the bone collagen of the marine mammals that reside in these waters. Marine mammal remains from four previously excavated archaeological deposits on Unalaska Island, Alaska are used as a proxy for marine production changes throughout the Holocene (4,500 BP to 350 BP). Historic and modern samples from museum collections, subsistence harvests, and previously published data provide a distinct …


A Characterization Of A Southeast Florida Stony Coral Assemblage After A Disease Event, Nicole K. Hayes Jul 2019

A Characterization Of A Southeast Florida Stony Coral Assemblage After A Disease Event, Nicole K. Hayes

HCNSO Student Theses and Dissertations

Coral reefs have declined globally due to anthropogenic stressors increasing the frequency and severity of bleaching and disease events. In 2014, a stony coral tissue loss disease (SCTLD) outbreak occurred off the coast of southeast Florida and subsequently spread throughout the region. Data collected by the Southeast Florida Reef Evaluation and Monitoring Project (SECREMP) were used to examine the regional impacts of the disease event on the Southeast Florida stony coral assemblage. A long-term annual monitoring project, SECREMP samples permanent sites along the Southeast Florida Reef Tract (SEFRT) from Miami-Dade County north to Martin County. Analysis of stony coral demographic …


Spatial And Temporal Trends In The Xestospongia Muta (Giant Barrel Sponge) Population On The Southeast Florida Reef Tract, Alanna D. Waldman Jul 2019

Spatial And Temporal Trends In The Xestospongia Muta (Giant Barrel Sponge) Population On The Southeast Florida Reef Tract, Alanna D. Waldman

HCNSO Student Theses and Dissertations

Xestospongia muta, the giant barrel sponge, is a key component of coral reef benthic communities in Southeast Florida and the Caribbean. Xestospongia muta increases habitat complexity and stability, and filters large volumes of water, enhancing water quality and facilitating nutrient cycling. Therefore, it is important to investigate trends in the X. muta population on Southeast Florida reefs in response to anthropogenic stressors, changing environmental conditions and acute disturbances and how these events affect its ecological role in the benthic community. This study identified trends in X. muta population density, volume, and size class distribution over time and across reef …


An Overview Of Handheld Sun Photometer Measurements Of Atmospheric Aerosols In New Orleans, Louisiana: A Case Study Of The Xavier University Study Site., M. Bradley, B. Sevalia, M. Gasseller Jul 2019

An Overview Of Handheld Sun Photometer Measurements Of Atmospheric Aerosols In New Orleans, Louisiana: A Case Study Of The Xavier University Study Site., M. Bradley, B. Sevalia, M. Gasseller

Faculty and Staff Publications

Aerosol optical depth (AOT) was measured at Xavier University of Louisiana (XULA, 29.96ᵒ N, 90.11° W and 3m above sea level) using a GLOBE handheld sun photometer. The measurements were done at two different wavelengths, 505nm and 625nm. The measured values were used to extrapolate the AOT values for wavelengths 667nm, 551nm, 532nm and 490nm at the XULA site. The measured and calculated AOT values were then compared with values from the nearest AERONET station at Wave CIS site 6 (AERONET, 28.87ᵒ N, 90.48° W and 33m above sea level), which is 60 miles south of XULA. In this study …


Timing And Potential Drivers Of Symbiont Selection In The Early Life Stages Of The Massive Starlet Coral Siderastrea Siderea, Sarah G. Koerner Jul 2019

Timing And Potential Drivers Of Symbiont Selection In The Early Life Stages Of The Massive Starlet Coral Siderastrea Siderea, Sarah G. Koerner

HCNSO Student Theses and Dissertations

The ability of corals to build reefs can be attributed to their relationship with single-celled algae of the familySymbiodiniaceae.Through the process of photosynthesis, these algae can provide their coral hosts with over 90% of their daily energy requirements. Most coral species acquire multiple species of symbionts from the surrounding water during their larval stage or immediately after settling. However, over time, the coral will select a dominant symbiont speciesthat can depend on the local environment. Until this study, the size or age of the coral at which this transition from multiple Symbiodiniaceaespecies to one dominant species occurs has remained …


Shallow- Water Hardbottom Communities Support The Separation Of Biogeographic Provinces On The West- Central Florida Gulf Coast, Shelby Eagan Jul 2019

Shallow- Water Hardbottom Communities Support The Separation Of Biogeographic Provinces On The West- Central Florida Gulf Coast, Shelby Eagan

HCNSO Student Theses and Dissertations

Several studies have found separation of biogeographic provinces on the West Florida Shelf (WFS), but the location of this separation differs depending on different organisms with faunal boundaries proposed at Apalachicola, Cedar Key, Anclote Key. Tampa Bay, Charlotte Harbor, Cape Romano, or Cape Sable. Biogeographic boundaries can be gradual over a given space and are often species-specific. Analyses of marine benthic mapping and community characterization of Florida’s West-central coast shallow water (depth) hardbottom habitats indicate a major shift in the benthos across Tampa Bay. Quantitative benthic surveys of 29 sites yielded a total of 4,079 individuals of nine stony coral …


Desperate Coral Larvae? Behavioral Responses To Settlement Cues In Aging Agaricia Agaricites Larvae, Helena Sasha Fulmore Jul 2019

Desperate Coral Larvae? Behavioral Responses To Settlement Cues In Aging Agaricia Agaricites Larvae, Helena Sasha Fulmore

HCNSO Student Theses and Dissertations

The global stressors of ocean warming and acidification, as well as local stressors such as eutrophication, overfishing, and coastal construction, have all contributed to the severe decline in coral populations worldwide. Recovery of coral reefs depends partly on recruitment, which relies on the response of larvae to settlement cues indicative of habitat quality; however, it remains unclear whether recruitment in disturbed areas will be compromised. Specifically, as reefs become more disturbed and dominated by macroalgae, it is important to understand larval behavior in response to changes in habitat quality. In this study, we first assessed the settlement success of newly …


Odu Expert Invited To Testify At Legislative Hearing On Coastal Resilience, Sarah Huddle Jul 2019

Odu Expert Invited To Testify At Legislative Hearing On Coastal Resilience, Sarah Huddle

News Items

No abstract provided.


Optimizing Lighting Regimes For Rearing Orbicella Faveolata And Acropora Cervicornis Recruits, Paul D. Kreh Jul 2019

Optimizing Lighting Regimes For Rearing Orbicella Faveolata And Acropora Cervicornis Recruits, Paul D. Kreh

HCNSO Student Theses and Dissertations

Coral reef decline worldwide has led to the need for coral reef restoration. The use of sexual reproduction in restoration efforts is required to increase genetic diversity; however, the procedures for rearing newly-settled coral recruits ex situ still need to be optimized. Recruits initially require low light irradiance, but it is unclear when higher irradiances are required to enhance growth and survival. Here we determined the optimal light regime for Orbicella faveolata and Acropora cervicornis recruits. Newly settled recruits were reared under treatments with varied rates of increasing irradiance (after reaching 5 weeks of age), and their survival, growth, and …


Management Regime And Habitat Response Influence Abundance Of Regal Fritillary (Speyeria Idalia) In Tallgrass Prairie, K. Mccullough, G. Albanese, D.A. Haukos, A.M. Ricketts, S. Stratton Jul 2019

Management Regime And Habitat Response Influence Abundance Of Regal Fritillary (Speyeria Idalia) In Tallgrass Prairie, K. Mccullough, G. Albanese, D.A. Haukos, A.M. Ricketts, S. Stratton

United States Geological Survey: Staff Publications

The >2,570,000-ha Flint Hills ecoregion of Kansas, USA, harbors the largest remaining contiguous tract of tallgrass prairie in North America, a unique system, as the remainder of North America’s tallgrass prairie has succumbed to development and conversion. Consequently, the loss and degradation of tallgrass prairie has reduced populations of many North American prairie-obligate species including the regal fritillary (Speyeria idalia) butterfly. Population abundance and occupied range of regal fritillary have declined >99%, restricting many populations to isolated, remnant patches of tallgrass prairie. Such extensive decline has resulted in consideration of the regal fritillary for protection under the Endangered Species Act. …


Microbial Analysis Of Surfactant-Associated Bacteria In The Sea Surface Microlayer And Remote Sensing Of Associated Slicks, Georgia Parks Jul 2019

Microbial Analysis Of Surfactant-Associated Bacteria In The Sea Surface Microlayer And Remote Sensing Of Associated Slicks, Georgia Parks

HCNSO Student Theses and Dissertations

The sea-surface microlayer (SML) is the boundary layer at the air-sea interface where many biogeochemical processes occur. Many organisms (e.g., bacteria) produce surface active agents (surfactants) for life processes, which accumulate in the SML and dampen short gravity-capillary waves, resulting in sea surface slicks. Synthetic aperture radar (SAR) is capable of remotely sensing these features on the sea surface by measuring reflected backscatter from the ocean surface in microwaves. This study coordinates SAR overpasses with in situ SML and subsurface (SSW) microbial sample collection to guide subsequent analysis after 16s rRNA sequencing on the Illumina MiSeq. In April …


Perchlorate Behavior In The Context Of Black Carbon And Metal Cogeneration Following Fireworks Emission At Oak Lake, Lincoln, Nebraska, Usa, Manish Kumar, Daniel D. Snow, Yusong Li, Patrick Shea Jul 2019

Perchlorate Behavior In The Context Of Black Carbon And Metal Cogeneration Following Fireworks Emission At Oak Lake, Lincoln, Nebraska, Usa, Manish Kumar, Daniel D. Snow, Yusong Li, Patrick Shea

Nebraska Water Center: Faculty Publications

The imprints of fireworks displays on the adjacent water body were investigated from the perspective of cogeneration of black carbon, metals and perchlorate (ClO4). In particular, the mixing and dissipation of ClO4 were studied at Oak Lake, Lincoln, Nebraska, following fireworks displays in 2015 and 2016. Following the display, ClO4 concentration in the water increased up to 4.3 μg/L and 4.0 μg/L in 2015 and 2016, respectively. A first-order model generally provided a good fit to the measured perchlorate concentrations from which the rate of dissipation was estimated as 0.07 d–1 in …


Cmip5 Models' Ability To Capture Observed Trends Under The Influence Of Shifts And Persistence: An In-Depth Study On The Colorado River Basin, Kazi Ali Tamaddun, Ajay Kalra, Sanjiv Kumar, Sajjad Ahmad Jul 2019

Cmip5 Models' Ability To Capture Observed Trends Under The Influence Of Shifts And Persistence: An In-Depth Study On The Colorado River Basin, Kazi Ali Tamaddun, Ajay Kalra, Sanjiv Kumar, Sajjad Ahmad

Civil and Environmental Engineering and Construction Faculty Research

This study evaluated the ability of phase 5 of the Coupled Model Intercomparison Project (CMIP5) to capture observed trends under the influence of shifts and persistence in their data distributions. A total of 41 temperature and 25 precipitation CMIP5 simulation models across 22 grid cells (2.5° × 2.5° squares) within the Colorado River basin were analyzed and compared with the Climate Research Unit Time Series (CRU-TS) observed datasets over a study period of 104 years (from 1901 to 2004). Both the modeled simulations and observations were tested for shifts, and the time series before and after the shifts were analyzed …


An Index To Better Estimate Tropical Cyclone Intensity Change In The Western North Pacific, Woojeong Lee, Sung-Hun Kim, Pao-Shin Chu, Il-Ju Moon, Alexander Soloviev Jul 2019

An Index To Better Estimate Tropical Cyclone Intensity Change In The Western North Pacific, Woojeong Lee, Sung-Hun Kim, Pao-Shin Chu, Il-Ju Moon, Alexander Soloviev

Marine & Environmental Sciences Faculty Articles

A revised predictor called the net energy gain rate (NGR) is suggested by considering wind dependent drag coefficient based on the existing maximum potential intensity theory. A series of wind speed dependent NGR, known as NGR‐w, is calculated based on pre‐tropical cyclone (TC) averaged ocean temperatures from the surface down to 120 m (at 10‐m intervals) to include the TC‐induced vertical mixing for 13 years (2004–2016) in the western North Pacific. It turns out that the NGR50‐w (NGR‐w based on temperature averaged over top 50 m) has the highest correlation with 24‐h TC intensity …


Some Environmental And Biological Determinants Of Coral Richness, Resilience And Reef Building In Galápagos (Ecuador), Bernhard Riegl, Matthew Johnston, Peter W. Glynn, Inti Keith, Fernando Rivera, Mariana Vera-Zambrano, Stuart Banks, Joshua Feingold, Peter J. Glynn Jul 2019

Some Environmental And Biological Determinants Of Coral Richness, Resilience And Reef Building In Galápagos (Ecuador), Bernhard Riegl, Matthew Johnston, Peter W. Glynn, Inti Keith, Fernando Rivera, Mariana Vera-Zambrano, Stuart Banks, Joshua Feingold, Peter J. Glynn

Marine & Environmental Sciences Faculty Articles

Throughout the Galápagos, differences in coral reef development and coral population dynamics were evaluated by monitoring populations from 2000–2019, and environmental parameters (sea temperatures, pH, NO3, PO43−) from 2015–19. The chief goal was to explain apparent coral community differences between the northern (Darwin and Wolf) and southern (Sta. Cruz, Fernandina, San Cristóbal, Española, Isabela) islands. Site coral species richness was highest at Darwin and Wolf. In the three most common coral taxa, a declining North (N)-South (S) trend in colony sizes existed for Porites lobata and Pocillopora spp., but not for Pavona spp. …


A Compilation Of Global Bio-Optical In Situ Data For Ocean-Colour Satellite Applications: Version Two, André Valente, Shubha Sathyendranath, Vanda Brotas, Steve Groom, Michael Grant, Malcolm Taberner, David Antoine, Robert Arnone, William M. Balch, Kathryn Baker, Ray Barlow, Simon Bélanger, Jean-François Berthon, Şükrü Beşiktepe, Yngve Borsheim, Astrid Bracher, Vittorio Brando, Elisabetta Canuti, Francisco Chavez, Andrés Cianca, Hervé Claustre, Lesley Clementson, Richard Crout, Robert Frounin, Carlos García-Soto, Stuart W. Gibb, Richard Gould, Stanford B. Hooker, Mati Kahru, Milton Kampel, Holger Klein, Susanne Kratzer, Raphael Kudela, Jesus Ledesma, Hubert Loisel, Patricia Matrai, David Mckee, Brian G. Mitchell, Tiffany Moisan, Frank Muller-Karger, Leonie O'Dowd, Michael Ondrusek, Trevor Platt, Alex J. Poulton, Michael Repecaud, Thomas Schroeder, Timothy Smyth, Denise Smyth-Wright, Heidi M. Sosik, Michael Twardoski, Vincenzo Vellucci, Kenneth Voss, Jeremy Werdell, Marcel Wernand, Simon Wright, Giuseppe Zibordi Jul 2019

A Compilation Of Global Bio-Optical In Situ Data For Ocean-Colour Satellite Applications: Version Two, André Valente, Shubha Sathyendranath, Vanda Brotas, Steve Groom, Michael Grant, Malcolm Taberner, David Antoine, Robert Arnone, William M. Balch, Kathryn Baker, Ray Barlow, Simon Bélanger, Jean-François Berthon, Şükrü Beşiktepe, Yngve Borsheim, Astrid Bracher, Vittorio Brando, Elisabetta Canuti, Francisco Chavez, Andrés Cianca, Hervé Claustre, Lesley Clementson, Richard Crout, Robert Frounin, Carlos García-Soto, Stuart W. Gibb, Richard Gould, Stanford B. Hooker, Mati Kahru, Milton Kampel, Holger Klein, Susanne Kratzer, Raphael Kudela, Jesus Ledesma, Hubert Loisel, Patricia Matrai, David Mckee, Brian G. Mitchell, Tiffany Moisan, Frank Muller-Karger, Leonie O'Dowd, Michael Ondrusek, Trevor Platt, Alex J. Poulton, Michael Repecaud, Thomas Schroeder, Timothy Smyth, Denise Smyth-Wright, Heidi M. Sosik, Michael Twardoski, Vincenzo Vellucci, Kenneth Voss, Jeremy Werdell, Marcel Wernand, Simon Wright, Giuseppe Zibordi

Faculty Publications

A global compilation of in situ data is useful to evaluate the quality of ocean-colour satellite data records. Here we describe the data compiled for the validation of the ocean-colour products from the ESA Ocean Colour Climate Change Initiative (OC-CCI). The data were acquired from several sources (including, inter alia, MOBY, BOUSSOLE, AERONET-OC, SeaBASS, NOMAD, MERMAID, AMT, ICES, HOT and GeP&CO) and span the period from 1997 to 2018. Observations of the following variables were compiled: spectral remote-sensing reflectances, concentrations of chlorophyll a, spectral inherent optical properties, spectral diffuse attenuation coefficients and total suspended matter. The data were from …


An Estimation Of Lower Tropospheric Mixing Derived From Inverse Modeling Of Boundary Layer Water Vapor Isotopologues On Graciosa Island, Azores, Jacquelyn M. Delp Jul 2019

An Estimation Of Lower Tropospheric Mixing Derived From Inverse Modeling Of Boundary Layer Water Vapor Isotopologues On Graciosa Island, Azores, Jacquelyn M. Delp

Earth and Planetary Sciences ETDs

Recent studies have shown water vapor isotopologues to be sensitive tracers of mixing processes that govern low-cloud feedback in climate models. In this study, we develop an inverse model (MBL Mix inverse model) that uses one year of isotope and humidity observations from Graciosa Island, Azores to estimate mixing for four seasons. We show the dry end-member of the model, the lower free troposphere (LFT), can be represented using Rayleigh fractionation. Isotope observations from Graciosa Island are compared to other field locations to discuss controls on isotopic variability other than mixing. Output from the MBL Mix inverse model shows the …


Population Demographics Of Golden Tilefish Lopholatilus Chamaeleonticeps In The Gulf Of Mexico, Greta J. Helmueller Jul 2019

Population Demographics Of Golden Tilefish Lopholatilus Chamaeleonticeps In The Gulf Of Mexico, Greta J. Helmueller

USF Tampa Graduate Theses and Dissertations

The Deepwater Horizon (DWH) oil spill had catastrophic impacts on aquatic organisms in the Northern Gulf of Mexico (GoM). Longline gear was used to sample demersal fish species at 344 locations distributed throughout the GoM in the seven years following DWH. Sampling was accomplished deploying 450-500 baited hooks per station in depths ranging from 20-600 m. Using data from these surveys, I analyzed the length and age frequency, condition, growth, and mortality rates of Golden Tilefish (Lopholatilus chamaeleonticeps) throughout the GoM. Demersal habitat use and apparent high contaminant levels in Golden Tilefish makes them potentially vulnerable to oil spills such …


Drought Analyses Of The Horn´E PoˇZitavie Region (Slovakia) In The Period 1966–2013, Jaroslav Vido, Paulina Nalevankova, Jan Valach, Zbysek Sustek, Tsegaye Tadesse Jul 2019

Drought Analyses Of The Horn´E PoˇZitavie Region (Slovakia) In The Period 1966–2013, Jaroslav Vido, Paulina Nalevankova, Jan Valach, Zbysek Sustek, Tsegaye Tadesse

National Drought Mitigation Center: Faculty Publications

+is study focuses on the characterization of historical drought occurrences in the Horn´e Poˇzitavie region of Slovakia over the period 1966–2013 using Standardized Precipitation-Evapotranspiration Index (SPEI). Trend analyses were evaluated by the Mann–Kendall (MK) test as well as cumulative sum of rank difference (CRD) test. +e results showed that drought occurs in the region regularly (recurrent climate feature), while the trend analysis indicated the trend toward more arid climatic conditions. However, CRD trend analyses showed that the subtrend changed direction toward less drier conditions in the late 1980s and early 1990s. Analyses of SPEI trends in individual months showed a …


Evaluating Future Reservoir Storage In The Rio Grande Using Normalized Climate Projections And A Water Balance Model, Nolan T. Townsend Jul 2019

Evaluating Future Reservoir Storage In The Rio Grande Using Normalized Climate Projections And A Water Balance Model, Nolan T. Townsend

Earth and Planetary Sciences ETDs

We develop and implement new tools for assessing the future of surface water supplies in downstream reaches of the Rio Grande, for which Elephant Butte Reservoir is the major storage reservoir. First, a normalization procedure is developed to adjust natural Rio Grande streamflows simulated by dynamical models in downstream reaches. The normalization accounts for upstream anthropogenic impairments to flow that are not considered in the model, thereby yielding downstream flows closer to observed values and more appropriate for use in assessments of future flows in downstream reaches. The normalization is applied to assess the potential effects of climate change on …


The Impact Of Energetic Neutral Particles Raining Down On The Thermosphere Due To Charge Exchange Reactions In The Upper Ionosphere And Polar Wind, Larry Gardner Jul 2019

The Impact Of Energetic Neutral Particles Raining Down On The Thermosphere Due To Charge Exchange Reactions In The Upper Ionosphere And Polar Wind, Larry Gardner

Funded Research Records

No abstract provided.


Wide-Ranging Temporal Variation In Transoceanic Movement And Population Mixing Of Bluefin Tuna In The North Atlantic Ocean, Michael A. Dance Jul 2019

Wide-Ranging Temporal Variation In Transoceanic Movement And Population Mixing Of Bluefin Tuna In The North Atlantic Ocean, Michael A. Dance

Faculty Publications

Uncertainty regarding the movement and population exchange of Atlantic bluefin tuna (Thunnus thynnus) from the two primary spawning areas (Gulf of Mexico, Mediterranean Sea) is increasingly implicated as a major impediment for the conservation of this species. Here, two mixture methods were applied to natural chemical markers (delta O-18 and delta C-13) in otoliths (ear stones) to comprehensively investigate the nature and degree of transoceanic movement and mixing of eastern and western populations in several areas of the North Atlantic Ocean that potentially represent mixing hotspots. Areas investigated occurred on both sides of the 45 degrees W management boundary as …


Evaluating Fluid Fluxes From Deep-Sea Seepage Habitats, Leigha E. Peterson Jul 2019

Evaluating Fluid Fluxes From Deep-Sea Seepage Habitats, Leigha E. Peterson

Electronic Theses and Dissertations

The permanently dark deep-sea, located at oceanic water depths greater than 200 m, represents the largest potential habitat space on Earth. The physicochemical conditions of the planet’s largest biome are tightly coupled to the exchange of matter and energy from terrestrial and sea-floor end-members. In fact, global ocean and climate systems are significantly impacted by deep-sea processes. Seafloor vents and seeps appear to act as geologic exchange conduits, returning recycled materials to the hydrosphere to sustain another generation of life. Despite submarine seepage having control on global elemental cycling, it is estimated that less than 1% of the deep-sea has …


Weather And Climate Summary And Forecast: July 2019 Report, Gregory V. Jones Jul 2019

Weather And Climate Summary And Forecast: July 2019 Report, Gregory V. Jones

Linfield University Wine Studies Reports

This report provides a summary of the weather and climate forecast for July 2019. It includes forecast information specific to the Pacific Northwest and the western United States, as well as forecast information for other portions of the United States and abroad.


An Estimation Of Lower Tropospheric Mixing Derived From Inverse Modeling Of Boundary Layer Water Vapor Isotopologues On Graciosa Island, Azores, Jacquelyn M. Delp Jul 2019

An Estimation Of Lower Tropospheric Mixing Derived From Inverse Modeling Of Boundary Layer Water Vapor Isotopologues On Graciosa Island, Azores, Jacquelyn M. Delp

Earth and Planetary Sciences ETDs

Recent studies have shown water vapor isotopologues to be sensitive tracers of mixing processes that govern low-cloud feedback in climate models. In this study, we develop an inverse model (MBL Mix inverse model) that uses one year of isotope and humidity observations from Graciosa Island, Azores to estimate mixing for four seasons. We show the dry end-member of the model, the lower free troposphere (LFT), can be represented using Rayleigh fractionation. Isotope observations from Graciosa Island are compared to other field locations to discuss controls on isotopic variability other than mixing. Output from the MBL Mix inverse model shows the …


Variations Of Global Ocean Salinity From Multiple Gridded Argo Products, Chao Liu Jul 2019

Variations Of Global Ocean Salinity From Multiple Gridded Argo Products, Chao Liu

USF Tampa Graduate Theses and Dissertations

Salinity is one of the fundamental ocean state variables. Variations of ocean salinity can be used to infer changes in the global water cycle and air-sea freshwater exchange. Many institutions have developed gridded Argo products of global coverage. However, the existing gridded salinity products have not yet been dedicatedly intercompare and assessed. In this study, the mean state, annual and interannual variabilities, and decadal changes of ocean salinity from five Argo-based gridded salinity products, available from UK Met Office, JAMSTEC, Scripps Institution of Oceanography, China Second Institute of Oceanography, and International Pacific Research Center, are examined and compared for their …


Sources And Chemical Stability Of Soil Organic Carbon Along A Salinity Gradient And A Chronosequence Of Created Brackish Marshes In Coastal Louisiana, Megan L. Kelsall Jul 2019

Sources And Chemical Stability Of Soil Organic Carbon Along A Salinity Gradient And A Chronosequence Of Created Brackish Marshes In Coastal Louisiana, Megan L. Kelsall

LSU Master's Theses

Tidal marshes have been recognized for providing a number of important ecological services including soil carbon sequestration. However, the loss of tidal marsh habitat due to climate change and anthropogenic stressors exposes previously stored soil organic carbon (SOC) to oxidation. The vulnerability of SOC to oxidation depends on its chemical stability and environmental conditions limiting decomposition. Labile organic carbon (LC), decomposes quickly unless abiotic conditions limit decomposition. Recalcitrant organic carbon (RC) decomposes slower and is stored for longer time periods. Predicting long-term storage of SOC is complicated by the potential for multiple SOC sources, differences in chemical stability, and variation …


Sediment Monitoring To Support Modeling A Reservoir Sediment Flush On A Sand-Bed River In Northern Nebraska, Nathaniel J. Schaepe, Paul M. Boyd Jul 2019

Sediment Monitoring To Support Modeling A Reservoir Sediment Flush On A Sand-Bed River In Northern Nebraska, Nathaniel J. Schaepe, Paul M. Boyd

United States Geological Survey: Water Reports and Publications

The United States Geological Survey (USGS) in cooperation with the United States Army Corps of Engineers (USACE), monitored a sediment flush event from Spencer Dam located on the Niobrara River near Spencer, Nebraska, during the fall of 2014. Data collected during the flush was used to validate a one-dimensional sediment transport model developed by the USACE. The USACE surveyed 26 cross sections within the reservoir and as far as 1 kilometer (km) upstream from the reservoir pool to about 10 km downstream from the dam before and after the flushing event to measure erosion and deposition. They also collected surficial …


Circulation, Vol. 24, No. 3, Center For Coastal Physical Oceanography, Eileen Hofmann, Brynn Pecher, Margaret Mulholland Jul 2019

Circulation, Vol. 24, No. 3, Center For Coastal Physical Oceanography, Eileen Hofmann, Brynn Pecher, Margaret Mulholland

CCPO Circulation

Summer 2019 issue of CCPO Circulation featuring article, "Combining Forces to Understand Harmful Algal Bloom Dynamics," by Eileen Hofmann, Brynn Pecher, and Margie Mulholland.