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Wavelength And Temperature-Dependent Apparent Quantum Yields For Photochemical Formation Of Hydrogen Peroxide In Seawater, David J. Kieber, Gary W. Miller, Patrick J. Neale, Kenneth Mopper Jan 2014

Wavelength And Temperature-Dependent Apparent Quantum Yields For Photochemical Formation Of Hydrogen Peroxide In Seawater, David J. Kieber, Gary W. Miller, Patrick J. Neale, Kenneth Mopper

Chemistry & Biochemistry Faculty Publications

Wavelength and temperature-dependent apparent quantum yields (AQYs) were determined for the photochemical production of hydrogen peroxide using seawater obtained from coastal and oligotrophic stations in Antarctica, the Pacific Ocean at Station ALOHA, the Gulf of Mexico, and at several sites along the East Coast of the United States. For all samples, AQYs decreased exponentially with increasing wavelength at 25 °C, ranging from 4.6 × 10−4 to 10.4 × 10−4 at 290 nm to 0.17 × 10−4 to 0.97 × 10−4 at 400 nm. AQYs for different seawater samples were remarkably similar irrespective of expected differences in the composition and concentrations …


Evolution Of The Freshwater Sardinella, Sardinella Tawilis (Clupeiformes: Clupeidae), In Taal Lake, Philippines And Identification Of Iits Marine Sister-Species, Sardinella Hualiensis, Demian Willette, Kent E. Carpenter, Mudjekeewis Santos Jan 2014

Evolution Of The Freshwater Sardinella, Sardinella Tawilis (Clupeiformes: Clupeidae), In Taal Lake, Philippines And Identification Of Iits Marine Sister-Species, Sardinella Hualiensis, Demian Willette, Kent E. Carpenter, Mudjekeewis Santos

Biological Sciences Faculty Publications

We identify the sister species of the world's only freshwater sardinella, Sardinella tawilis (Herre, 1927) of Taal Lake, Philippines as the morphologically-similar marine Taiwanese sardinella Sardinella hualiensis (Chu and Tsai, 1958). Evidence of incomplete lineage sorting and a species tree derived from three mitochondrial genes and one nuclear gene indicate that S. tawilis diverged from S. hualiensis in the late Pleistocene. Neutrality tests, mismatch distribution analysis, sequence diversity indices, and species tree analysis indicate populations of both species have long been stable and that the divergence between these two lineages occurred prior to the putative 18th century formation of Taal …


Brownfield Action: Dissemination Of A Sencer Model Curriculum And The Creation Of A Collaborative Stem Education Network, Peter Bower, Ryan Kelsey, Joseph Liddicoat, Doug M. Thompson, Angelo Lampousis, Bret Bennington, Bess Greenbaum Seewald, Arthur D. Kney, Saugata Datta, Lawrence D. Lemke, Briane Sorice Miccio, Tamara Graham Jan 2014

Brownfield Action: Dissemination Of A Sencer Model Curriculum And The Creation Of A Collaborative Stem Education Network, Peter Bower, Ryan Kelsey, Joseph Liddicoat, Doug M. Thompson, Angelo Lampousis, Bret Bennington, Bess Greenbaum Seewald, Arthur D. Kney, Saugata Datta, Lawrence D. Lemke, Briane Sorice Miccio, Tamara Graham

Publications and Research

Brownfield Action (BA) is a web-based environmental site assessment (ESA) simulation in which students form geotechnical consulting companies and work together to solve problems in environmental forensics. Developed at Barnard College with the Columbia Center for New Media Teaching and Learning, BA has been disseminated to ten colleges, universities, and high schools, resulting in a collaborative network of educators. The experiences of current users are presented describing how they have incorporated the BA curriculum into their courses, as well as how BA affected teaching and learning. The experiences demonstrate that BA can be used in whole or in part, is …


Temporal And Spatial Characterization Of Macondo 252 Signatures In Gulf Of Mexico Shelf And Slope Sediments, Olivia P. Woodruff Jan 2014

Temporal And Spatial Characterization Of Macondo 252 Signatures In Gulf Of Mexico Shelf And Slope Sediments, Olivia P. Woodruff

Theses and Dissertations--Earth and Environmental Sciences

The long-term fate of hydrocarbons in the Gulf of Mexico (GOMx) following the 2010 Deepwater Horizon oil spill has yet to be fully characterized. Elemental (% C and % N), stable isotopes (δ13Corganic), and polycyclic aromatic hydrocarbon (PAH) molecular signatures were investigated in shelf and slope sediments collected in October 2010 and 2011 to gain insight into processes affecting the distribution and fate of spilled Macondo oil. Particulate organic carbon (POC) ranged between 1.55 and 2.22 wt. % in 2010 and 0.55 and 2.06 % in 2011 while the corresponding δ13Corganic ranges were …


A Petrographic Characterization Of The Leatherwood Coal Bed In Eastern Kentucky, Michelle N. Johnston Jan 2014

A Petrographic Characterization Of The Leatherwood Coal Bed In Eastern Kentucky, Michelle N. Johnston

Theses and Dissertations--Earth and Environmental Sciences

The Eastern Kentucky Coal Field is located in the central portion of the Appalachian Basin. The Pennsylvanian Breathitt Formation in this region is characterized by numerous sequences of bituminous coal-bearing sedimentary rocks. These coals have distinct maceral compositions due to variations in depositional environments. Coal characterization is an important method for determining conditions that influenced peat accumulation and overall depositional settings of mires.

This study focuses on the characterization of the maceral composition of the Middle Pennsylvanian-age Leatherwood coal bed. It utilizes petrographical, palynological, and geochemical analyses to describe specific depositional environments and associated peat accumulation conditions.

Petrographic analyses indicate …


The Nature And Origin Of Cyclicity In The Cleveland Member Of The Ohio Shale (Upper Devonian), Northeastern Kentucky, U.S.A., Alice C. O'Bryan Jan 2014

The Nature And Origin Of Cyclicity In The Cleveland Member Of The Ohio Shale (Upper Devonian), Northeastern Kentucky, U.S.A., Alice C. O'Bryan

Theses and Dissertations--Earth and Environmental Sciences

The Cleveland Shale displays a characteristic and distinctive pattern of promontories and recessed intervals on weathered outcrops, which appears to represent cyclicity. This weathering pattern can be observed in other shales, both within and outside the Appalachian Basin; so determining the nature of these cycles may be critical for understanding the origin of, not only the Cleveland Shale, but also of black shales in general. Cyclicity in the Cleveland was examined on a decimeter-to-meter scale using lithologic characterization, gamma-ray stratigraphy and x-ray fluorescence, and on a millimeter-to-centimeter scale using organic petrography. Lithologic characterization and gamma-ray stratigraphy revealed Milankovitch-band fourth- and …


Biomechanical Effects Of Trees And Soil Thickness In The Cumberland Plateau, Michael Shouse Jan 2014

Biomechanical Effects Of Trees And Soil Thickness In The Cumberland Plateau, Michael Shouse

Theses and Dissertations--Geography

Previous research in the Ouachita Mountains, Arkansas suggests that, on relatively thin soils overlying bedrock, individual trees locally thicken the regolith by root penetration into bedrock. However, that work was conducted mainly in areas of strongly dipping and contorted rock, where joints and bedding planes susceptible to root penetration are more common and accessible. This project extended this concept to the Cumberland Plateau, Kentucky, with flat, level-bedded sedimentary rocks. Spatial variability of soil thickness was quantified at three nested spatial scales, and statistical relationships with other potential influences of thickness were examined. In addition, soil depth beneath trees was compared …


Natural Phenomena As Potential Influence On Social And Political Behavior: The Earth’S Magnetic Field, Jackie R. East Jan 2014

Natural Phenomena As Potential Influence On Social And Political Behavior: The Earth’S Magnetic Field, Jackie R. East

Theses and Dissertations--Political Science

Researchers use natural phenomena in a number of disciplines to help explain human behavioral outcomes. Research regarding the potential effects of magnetic fields on animal and human behavior indicates that fields could influence outcomes of interest to social scientists. Tests so far have been limited in scope. This work is a preliminary evaluation of whether the earth’s magnetic field influences human behavior it examines the baseline relationship exhibited between geomagnetic readings and a host of social and political outcomes. The emphasis on breadth of topical coverage in these statistical trials, rather than on depth of development for any one model, …


From Geology To Art History: Ceramist Alexandre Brongniart’S Overlooked Contribution To The Developing Science Of Art History In The Early Nineteenth Century, Julia A. Carr-Trebelhorn Jan 2014

From Geology To Art History: Ceramist Alexandre Brongniart’S Overlooked Contribution To The Developing Science Of Art History In The Early Nineteenth Century, Julia A. Carr-Trebelhorn

Theses and Dissertations--Art and Visual Studies

Alexandre Brongniart was known for his work as an important geologist and as an administrator at the Sèvres Porcelain Manufactory, but his roles as art historian and museologist are overlooked. Brongniart created a holistic methodology taken directly from science and applied it to ceramic art of all cultures and eras. He had a uniquely modern perspective on time, world culture, and archeology. Brongniart wrote about the art of Asia and the Americas on an equal status with that of the Classical West at least fifty years before it became a mainstream idea. Brongniart integrated scientific principle and practice into the …


Monitoring The Influence Of Acid Deposition On Soil And Implications To Forest Health In The Daniel Boone National Forest, Tyler M. Sanderson Jan 2014

Monitoring The Influence Of Acid Deposition On Soil And Implications To Forest Health In The Daniel Boone National Forest, Tyler M. Sanderson

Theses and Dissertations--Forestry and Natural Resources

Combustion of fossil fuels has contributed to many environmental problems including acid deposition. The Clean Air Act (CAA) was created to reduce ecological problems by cutting emissions of sulfur and nitrogen. Reduced emissions and rainfall concentrations of acidic ions have been observed since the enactment of the CAA, but soils continue to receive some acid inputs. Soils sensitive to acid deposition have been found to have low pH, a loss of base cations and a shift in the mineral phase controlling the activity of Al3+ and/or SO42-. If inputs continue, soil may be depleted of base …


Reconstruction Of The Hirnantian (Late Ordovician) Palaeotopography In The Upper Yangtze Region, Linna Zhang, Junxuan Fan, Qing Chen, Shuang-Ye Wu Jan 2014

Reconstruction Of The Hirnantian (Late Ordovician) Palaeotopography In The Upper Yangtze Region, Linna Zhang, Junxuan Fan, Qing Chen, Shuang-Ye Wu

Department of Earth, Environment and Sustainability Faculty Publications

Reconstruction of the Hirnantian (Late Ordovician) palaeotopography in South China is important for understanding the distribution pattern of the Hirnantian marine depositional environment. In this study, we reconstructed the Hirnantian palaeotopography in the Upper Yangtze region based on the rankings of the palaeo-water depths, which were inferred according to the lithofacies and biofacies characteristics of the sections. Data from 374 Hirnantian sections were collected and standardized through the online Geobiodiversity Database. The Ordinary Kriging interpolation method in the ArcGIS software was applied to create the continuous surface of the palaeo-water depths, i.e. the Hirnantian palaeotopography. Meanwhile, the line transect analysis …


A Microscopic Approach To The Pedogenic Formation Of Palygorskite Associated With Quaternary Calcretes Of The Adana Area, Southern Turkey, Meryem Yeşi̇lot Kaplan, Muhsi̇n Eren, Selahatti̇n Kadi̇r, Seli̇m Kapur, Jennifer Huggett Jan 2014

A Microscopic Approach To The Pedogenic Formation Of Palygorskite Associated With Quaternary Calcretes Of The Adana Area, Southern Turkey, Meryem Yeşi̇lot Kaplan, Muhsi̇n Eren, Selahatti̇n Kadi̇r, Seli̇m Kapur, Jennifer Huggett

Turkish Journal of Earth Sciences

Quaternary calcretes in the Adana area (southern Turkey) are widespread and occur in a variety of forms such as nodular, columnar/tubular, fracture-infill, laminated hardpan, and conglomeratic crusts. Palygorskite associated with calcrete nodules, tubes, and fracture-infills in the columnar horizon and adjacent host-rock mudstones suggests a cogenetic formation. The Beta-fabric (biogenic) constituents and stable isotope values of calcretes support a pedogenic origin for calcretes and also palygorskite. Extensions of palygorskite fibre and fibre bundles from euhedral to subhedral calcite crystals in calcretes and from smectite flakes in adjacent host-rock mudstone suggest an authigenic origin related to calcretisation in which precipitation and …


Alteration Mineral Mapping With Aster Data By Integration Of Coded Spectral Ratio Imaging And Som Neural Network Model, Mohammad Hassan Tayebi, Majid Hashemi Tangestani, Robert Keller Vincent Jan 2014

Alteration Mineral Mapping With Aster Data By Integration Of Coded Spectral Ratio Imaging And Som Neural Network Model, Mohammad Hassan Tayebi, Majid Hashemi Tangestani, Robert Keller Vincent

Turkish Journal of Earth Sciences

This study applied coded spectral ratio imaging and a self-organizing map (SOM) neural network model for subpixel classification of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data to map alteration minerals of the Masahim volcano, SE Iran. Spectra of samples were measured using a FieldSpec spectroradiometer, and were interpreted for finding key alteration minerals. Key minerals including sericite and kaolinite were selected. Thirty-six nonreciprocal spectral ratios of 9 ASTER reflective bands were created. Each spectral parameter (of 9 spectral bands and 36 spectral ratios) for the field and library mineral spectra was divided into deciles. Each decile of spectral …


Comparison Of Life Experiences Of Men And Women In The Sciences, Tori Nicole Quist Jan 2014

Comparison Of Life Experiences Of Men And Women In The Sciences, Tori Nicole Quist

Honors Program Theses

A lack of sense of belonging and stereotype threat have been shown to contribute to women leaving the sciences (Seymour, 1997; Beasley & Fischer, 2012; Deemer et al., 2013). Contributing to this is the fact that most women find affirmation externally (through friends, family and professors) for their life decisions (Seymour, 1997; Zeldin, 2000). A set of comparative studies in 2000 and 2008 were done examining factors affecting women’s and men’s choices of majors and careers (Zeldin, 2000 and Zeldin, 2008). These studies concluded that men relied on achievements in science as the source of their career decisions to enter …


Evaluation Of Stromatolites From The 3.4 Ga Kromberg Formation, Barberton Greenstone Belt, South Africa, Corey E. Shircliff Jan 2014

Evaluation Of Stromatolites From The 3.4 Ga Kromberg Formation, Barberton Greenstone Belt, South Africa, Corey E. Shircliff

LSU Master's Theses

Silicified sedimentary rocks from the 3.4 Ga Kromberg Formation of the Barberton Greenstone Belt in South Africa contain laminated structures that have been identified as possible stromatolites in the field. Morphological evaluation and a variety of chemical analyses are presented here, in an effort to describe the samples in a sedimentary context and consider biogenicity of these laminated forms. Two major types of laminated structures were identified in the field – domical laminates and flat-laminated samples with little to no synoptic relief. The domical sample presents the best morphological evidence for biogenicity. There are several characteristics that suggest the deposition …


Oxygen Isotope Composition Of Phosphate Along Vertical Weathering Profiles That Developed On Igneous Rocks: Testing Modern Analogues For Identifying Terrestrial Life In Ancient Paleosols, Dustin Warn Boyd Jan 2014

Oxygen Isotope Composition Of Phosphate Along Vertical Weathering Profiles That Developed On Igneous Rocks: Testing Modern Analogues For Identifying Terrestrial Life In Ancient Paleosols, Dustin Warn Boyd

LSU Master's Theses

Life on Earth began in its early oceans before moving on to land. Determining the exact timing of an established biosphere on land, however, has been elusive, due largely to the lack of either fossil or chemical evidence on land deposits. Here I test a hypothesis that the activity of land biota can be recorded in the oxygen isotope composition of phosphate in weathering profiles developed on igneous parent rocks. Igneous rock contains phosphate (PO43-), which is readily utilized for biological activities during soil development. The oxygen in PO43- does not readily exchange its oxygen …


Modeling Near Surface, Gas-Induced Seafloor Deformation Using Thin Plate Mechanics In The Thunder Horse Oil Field, Gulf Of Mexico And Ninilchik Field, Cook Inlet Basin, Alaska, Michael I. Thoma Jan 2014

Modeling Near Surface, Gas-Induced Seafloor Deformation Using Thin Plate Mechanics In The Thunder Horse Oil Field, Gulf Of Mexico And Ninilchik Field, Cook Inlet Basin, Alaska, Michael I. Thoma

LSU Master's Theses

Seabed topographic expressions such as pockmarks and domes caused by the vertical migration and accumulation of methane are found in muddy, cohesive sea beds around the world. These surface features range from 10-1000 m in diameter and 1-20 m in relief (Judd and Hovland, 2007). The mechanics of soft, cohesive sediment deformation due to overpressure from rising gas is not well understood or quantitatively defined despite the hazards they present to offshore drilling. Shallow gas pockets and overpressured sediments formed by the migration of subsurface gas to the seafloor can cause drilling blowouts, resulting in the release of large amounts …


Molecular Characterization And Photochemical Transformation Of Dissolved Organic Matter From Land To Ocean, Hongmei Chen Jan 2014

Molecular Characterization And Photochemical Transformation Of Dissolved Organic Matter From Land To Ocean, Hongmei Chen

Chemistry & Biochemistry Theses & Dissertations

Molecular characterization and photochemical transformation of dissolved organic matter (DOM) in both rivers and the ocean is the main research focus of this dissertation. Chemical characterization of DOM is hampered by the limited application of advanced techniques to desalt, concentrate, isolate and then molecularly characterize DOM. An affordable, commercially available mini-electrodialysis (mini-ED) system has been evaluated and recommended for the efficient desalting of small volume samples of seawater prior to analysis by electrospray Fourier transform ion cyclotron resonance mass spectrometry (ESI FTICR-MS).

A high-recovery technique of DOM isolation – reverse osmosis coupled with electrodialysis (RO/ED) – was used to isolate …


Surface Complexation Of Monosubstituted Organoarsenicals On Hematite: Atr-Ftir Investigations, Md Abdus Sabur Jan 2014

Surface Complexation Of Monosubstituted Organoarsenicals On Hematite: Atr-Ftir Investigations, Md Abdus Sabur

Theses and Dissertations (Comprehensive)

Little is known about the surface chemistry of organoarsenic compounds with iron-containing materials commonly found in geosorbents and arsenic removal technologies. In this thesis, these organoarsenicals include aliphatic and aromatic arsenicals that historically have been used as herbicides, pesticides and in the poultry feed industry, respectively. Attenuated total internal reflectance Fourier transform infrared spectroscopy has been used to study the surface interactions of organoarsenicals at the molecular level under various environmentally-relevant conditions. Kinetic and thermodynamic parameters extracted from these molecular level experiments provide trends that are not observed in any published bulk experiments. Apparent initial rates of adsorption and desorption …


Untangling Earth System Responses Recorded In Sulfate's Sulfur And Oxygen Isotopes At The Dawn Of Multicellular Life And Today, Bryan Alan Killingsworth Jan 2014

Untangling Earth System Responses Recorded In Sulfate's Sulfur And Oxygen Isotopes At The Dawn Of Multicellular Life And Today, Bryan Alan Killingsworth

LSU Doctoral Dissertations

Major Earth system perturbations in the deep past and today are recorded in sulfate sulfur and oxygen isotopes, as examined here in three cases. (1) Sedimentary sulfate record of the “Marinoan Oxygen-17 Depletion” (MOSD) event, implies ultra-high CO2 atmosphere at ~635 Ma after global glaciation. MOSD duration is constrained by correlating its most complete record to radiometric dates. Barium sulfate layers in South China sediments show the MOSD in lower layers but persistently absent up section. Carbon-13 correlation locates the MOSD within dated intervals from other sites, yielding a 0 - 0.99 Myr duration. Thus, sedimentary constraint on this non-steady-state …


How Unusual Is Tropical Storm Irene? A Case Study Of Storm Deposition In Littleville Lake, Huntington, Ma, Catherine Dunn Jan 2014

How Unusual Is Tropical Storm Irene? A Case Study Of Storm Deposition In Littleville Lake, Huntington, Ma, Catherine Dunn

Honors Papers

Tropical Storm Irene hit the northeastern United States in August 2011 with impressive rates of precipitation and river discharge. However, it was the combination of this heavy rain with high antecedent soil moisture that made Irene so unusual. The Connecticut River had a particularly high sediment yield after the storm, with a sediment concentration over 1,000 mg/L at the mouth of the river. Littleville Lake on the Westfield River was selected as a study site because of its flood control feature, which allows for the calculation of trapping efficiency in dammed rivers. Coring in the lake showed that there was …


Contrasting Biogeochemical Cycles Of Cobalt In The Surface Western Atlantic Ocean, Gabrial Dulaquais, Marie Boye, Rob Middag, Stephanis Owens, Viene Puigcorbe, Ken Buesseler, Pere Masque´, Hein J. De Baar, Xavier Carton Jan 2014

Contrasting Biogeochemical Cycles Of Cobalt In The Surface Western Atlantic Ocean, Gabrial Dulaquais, Marie Boye, Rob Middag, Stephanis Owens, Viene Puigcorbe, Ken Buesseler, Pere Masque´, Hein J. De Baar, Xavier Carton

Research outputs 2014 to 2021

Dissolved cobalt (DCo; 0.2μm; 10%) to the DCo stock of the mixed layer in the equatorial and north subtropical domains. Biotic and abiotic processes as well as the physical terms involved in the biogeochemical cycle of Co were defined and estimated. This allowed establishing the first global budget of DCo for the upper 100m in the western Atlantic. The biological DCo uptake flux was the dominant sink along the section, as reflected by the overall nutrient-type behavior of DCo. The regeneration varied widely within the different biogeochemical domains, accounting for 10% of the DCo-uptake rate in the subarctic gyre and …


What Do Elevated Background Contaminant Concentrations Mean For Amd Risk Assessment And Management In Western Australia?, C. D. Mccullough, J. J Pearce Jan 2014

What Do Elevated Background Contaminant Concentrations Mean For Amd Risk Assessment And Management In Western Australia?, C. D. Mccullough, J. J Pearce

Research outputs 2014 to 2021

Water quality contaminants include a range of naturally occurring chemicals that can cause degradation of aquatic ecosystem water values when concentration ranges exceed biological tolerances. Both acid and metalliferous drainage (AMD) and acid sulfate soil (ASS) can increase contaminant concentrations through reduced pH and increased solute concentrations especially of toxic metals and metalloids. Water quality guideline criteria are typically used to maintain existing end use value objectives when managing AMD/ASS-affected waters. However, surface and ground waters of catchments comprising mining resources often show elevated solute concentrations in baseline conditions due to their unique geologies. From an AMD and ASS risk …


Bramatherium (Artiodactyla, Ruminantia, Giraffidae) From The Middle Siwaliks Of Hasnot, Pakistan: Biostratigraphy And Palaeoecology, Muhammad Akbar Khan, Muhammad Akhtar, Ammara Irum Jan 2014

Bramatherium (Artiodactyla, Ruminantia, Giraffidae) From The Middle Siwaliks Of Hasnot, Pakistan: Biostratigraphy And Palaeoecology, Muhammad Akbar Khan, Muhammad Akhtar, Ammara Irum

Turkish Journal of Earth Sciences

We describe here new remains of the giraffid Bramatherium, from the late Miocene-early Pliocene of Hasnot, northern Pakistan. The fossil giraffid material from Hasnot represents 2 taxa of Bramatherium, B. megacephalum and B. grande. The Hasnot locality is characterised by high proportions of ruminants, namely Boselaphini, Antilopini, Sivatheriinae, Cervini, Dorcatherium, and Dorcabune. The Hasnot fossil ruminant assemblage is fairly typical for the Siwalik province and comparisons with the Greco-Iranian-Afghan and African palaeobiological provinces indicate a late Miocene-early Pliocene age. It is suggested that local Hasnot palaeoenvironments comprised wetlands to woodland biomes, perhaps devoid of expansive dense forests.


Exploring Changes In Detrital Flocculent Layer Dynamics Due To Shifts In Macrophyte Communities In The Northern Everglades, Erin Leigh Mckenney Jan 2014

Exploring Changes In Detrital Flocculent Layer Dynamics Due To Shifts In Macrophyte Communities In The Northern Everglades, Erin Leigh Mckenney

Dissertations, Master's Theses and Master's Reports - Open

A shift in plant communities of the Water Conservation Areas (WCAs) within the Everglades has been linked to changes in hydrology and high levels of nutrient loading from surrounding agicultural areas. This has resulted in the encroachment of dense cattail stands (Typha domingensis) into areas that had previously been a ridge and slough landscape populated primarily by native sawgrass (Cladium jamaicense). In order to study ecological management solutions in this area, WCA-2A was broken into study plots; several of which became open water areas through the application of herbicide and burning regimens. The open water areas …


Combining Limnology And Palaeolimnology To Investigate Recent Regime Shifts In A Shallow, Eutrophic Lake, Linda Randsalu-Wendrup, Daniel J. Conley, Jacob Carstensen, Lars-Anders Hansson, Christer Brönmark, Sherilyn C. Fritz, Preetam Choudhary, Joyanto Routh, Dan Hammarlund Jan 2014

Combining Limnology And Palaeolimnology To Investigate Recent Regime Shifts In A Shallow, Eutrophic Lake, Linda Randsalu-Wendrup, Daniel J. Conley, Jacob Carstensen, Lars-Anders Hansson, Christer Brönmark, Sherilyn C. Fritz, Preetam Choudhary, Joyanto Routh, Dan Hammarlund

Department of Earth and Atmospheric Sciences: Faculty Publications

In this study, we demonstrate that an integrated approach, combining palaeolimnological records and limnological monitoring data, can increase our understanding of changing ecological patterns and processes in shallow lakes. We focused on recent regime shifts in shallow Lake Krankesjön, southern Sweden, including the collapse of the clear-water state in 1975 and its subsequent recovery in the late 1980s. We used diatom, hydrocarbon, and biogenic silica sediment records, in concert with limnological data sets on nutrient concentrations, water clarity, chlorophyll-a and water depth, to investigate the shifts. The shift from clear to turbid conditions was abrupt and occurred over 1 to …


Modeling Tidally Driven Coulomb Failure At Strike-Slip Linea On Europa, Marissa Elizabeth Cameron Jan 2014

Modeling Tidally Driven Coulomb Failure At Strike-Slip Linea On Europa, Marissa Elizabeth Cameron

Open Access Theses & Dissertations

The surface of Europa is crosscut by a dense network of fractures and there are many candidate faults for studying past tectonic activity. To better understand the role of tidal stress sources and implications for faulting on Europa, we investigate the relationship between shear and normal stresses at four fault zones: Agenor Linea, Rhadamanthys Linea, Conamara Chaos (Agave/Asterius Linea), and Astypalaea Linea, offering a unique comparison of geological activity of fractures residing in geographically diverse locations of Europa. Assuming tidal diurnal and non-synchronous rotation (NSR) stresses are the primary mechanisms for strike-slip tectonism, here we investigate the mechanics of Coulomb …


Wetland Issues Affecting Waterfowl Conservation In North America, Heath M. Hagy, Scott C. Yaich, John W. Simpson, Eduardo Carrera, David A. Haukos, W.Carter Johnson, Charles R. Loesch, Fritz A. Reid, Scott E. Stephens, Ralph W. Tiner, Brett A. Werner, Greg S. Yarris Jan 2014

Wetland Issues Affecting Waterfowl Conservation In North America, Heath M. Hagy, Scott C. Yaich, John W. Simpson, Eduardo Carrera, David A. Haukos, W.Carter Johnson, Charles R. Loesch, Fritz A. Reid, Scott E. Stephens, Ralph W. Tiner, Brett A. Werner, Greg S. Yarris

Natural Resource Management Faculty Publications

This paper summarises discussions by invited speakers during a special session at the 6th North American Duck Symposium on wetland issues that affect waterfowl, highlighting current ecosystem challenges and opportunities for the conservation of waterfowl in North America. Climate change, invasive species, U.S. agricultural policy (which can encourage wetland drainage and the expansion of row-crop agriculture into grasslands), cost and competition for water rights, and wetland management for non-waterfowl species were all considered to pose significant threats to waterfowl populations in the near future. Waterfowl populations were found to be faced with significant threats in several regions, including: the Central …


The Response Of Lake Pontchartrain Fish Assemblages To Hurricanes Katrina And Rita, Martin T. O'Connell, Ann M.U. O'Connell, Christopher Schieble Jan 2014

The Response Of Lake Pontchartrain Fish Assemblages To Hurricanes Katrina And Rita, Martin T. O'Connell, Ann M.U. O'Connell, Christopher Schieble

Earth and Environmental Sciences Faculty Publications

To assess possible impacts on Lake Pontchartrain fishes from the 2005 hurricanes, we 45 compared trawl, beach seine, and gillnet collections taken before (2000-2003, 2005) and after 46 (2006-2009) to determine if significant assemblage changes occurred. We also compared basic 47 environmental variables to test for hurricane-related changes. Significant post-hurricane changes 48 in fish assemblages occurred in trawl (ANOSIM, R < 0.090, p < 0.05) and beach seine 49 (ANOSIM, R < 0.120, p < 0.05) collections across all seasons. Gillnet assemblages exhibited 50 changes in only one season (ANOSIM, R = 0.045, p < 0.05). These consistently low global R 51 values (all R < 0.120) across all gears suggest only minor compositional changes in species. 52 When peak abundance periods were compared for individual species, Gulf menhaden 53 (Brevoortia patronus) declined in trawl collections after the hurricanes (Friedman’s test, χ2 = 54 6.00, p = 0.014) but increased in gillnet collections (Friedman’s test, χ2=5.00, p = 0.025). 55 Hardhead catfish (Ariopsis felis) increased in trawl collections, but Gulf pipefish (Syngnathus 56 scovelli), naked gobies (Gobiosoma bosc), and rough silverside (Membras martinica) all 57 declined in beach seine samples and Atlantic croakers (M. undulatus), Spanish mackerel 58 (Scomberomorus maculatus), and sand seatrout (Cynoscion arenarius) all declined in gillnet 59 samples. In general, salinity increased and water clarity and dissolved oxygen decreased after 60 the hurricanes. While the overall composition of Lake Pontchartrain fish assemblages remains 61 stable, the significant decline of some species and changes in certain environmental variables are 62 cause for concern. Future monitoring should determine if all elements of this estuary will 63 recover from these impacts.


Comparison Of Instrumentation To Measure Air And Soil-Surface Temperature Variability In Northern Alaska, Katrina Keleher Jan 2014

Comparison Of Instrumentation To Measure Air And Soil-Surface Temperature Variability In Northern Alaska, Katrina Keleher

Undergraduate Theses, Professional Papers, and Capstone Artifacts

The Circumpolar Active Layer Monitoring (CALM) project has been observing permafrost (perennially frozen ground) and its overlaying active layer (which freezes and thaws annually) in northern Alaska’s Kuparuk River watershed and throughout the polar regions since the mid 1990’s to detect long-term responses to climatic change. The soil-surface temperature data is collected by thermistors that were positioned immediately below the surface of the ground at nine locations within a transect of 1-ha plots arranged from north to south across the region. Locations within each plot were individually selected to represent a full range of microsite conditions, with distinctions in vegetation, …