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Iac Gene Expression In The Indole-3-Acetic Acid-Degrading Soil Bacterium Enterobacter Soli Lf7, Isaac V. Greenhut, Beryl L. Slezak, Johan H. J. Leveau Oct 2018

Iac Gene Expression In The Indole-3-Acetic Acid-Degrading Soil Bacterium Enterobacter Soli Lf7, Isaac V. Greenhut, Beryl L. Slezak, Johan H. J. Leveau

Plant and Soil Sciences Faculty Publications

We show for soil bacterium Enterobacter soli LF7 that the possession of an indole-3-acetic acid catabolic (iac) gene cluster is causatively linked to the ability to utilize the plant hormone indole-3-acetic acid (IAA) as a carbon and energy source. Genome-wide transcriptional profiling by mRNA sequencing revealed that these iac genes, chromosomally arranged as iacHABICDEFG and coding for the transformation of IAA to catechol, were the most highly induced (>29-fold) among the relatively few (iac cluster were genes for a major facilitator superfamily protein (mfs) and enzymes of the β-ketoadipate pathway (pcaIJD-catBCA), which channels …


Correlates Of Rate Heterogeneity In Avian Ecomorphological Traits, A. M. Chira, C. R. Cooney, Jen A. Bright, E. J. R. Capp, E. C. Hughes, C. J. A. Moody, L. O. Nouri, Z. K. Varley, G. H. Thomas Oct 2018

Correlates Of Rate Heterogeneity In Avian Ecomorphological Traits, A. M. Chira, C. R. Cooney, Jen A. Bright, E. J. R. Capp, E. C. Hughes, C. J. A. Moody, L. O. Nouri, Z. K. Varley, G. H. Thomas

School of Geosciences Faculty and Staff Publications

Heterogeneity in rates of trait evolution is widespread, but it remains unclear which processes drive fast and slow character divergence across global radiations. Here, we test multiple hypotheses for explaining rate variation in an ecomorphological trait (beak shape) across a globally distributed group (birds). We find low support that variation in evolutionary rates of species is correlated with life history, environmental mutagenic factors, range size, number of competitors, or living on islands. Indeed, after controlling for the negative effect of species' age, 80% of variation in species‐specific evolutionary rates remains unexplained. At the clade level, high evolutionary rates are associated …


Osl Dating Of The Tolleston Beach At Indiana Dunes National Lakeshore And Its Implications For Interpreting The Archaeological Record, Malgorzata Mahoney Oct 2018

Osl Dating Of The Tolleston Beach At Indiana Dunes National Lakeshore And Its Implications For Interpreting The Archaeological Record, Malgorzata Mahoney

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

The puzzling scarcity of archaeological sites on the Tolleston Beach, the most lakeward shoreline complex at Indiana Dunes National Lakeshore, prompted an investigation into the development of these parabolic dunes in an attempt to determine whether the distribution of known archaeological sites is governed by ancient human behaviors, or influenced by its dune setting which can affect site preservation and discoverability. In order to accurately understand patterns of past human occupation, it is important to know the timing and extent of dune reactivation. Specifically, whether it was frequent enough to influence settlement patterns in the past, or if it was …


Small Shelly Fossil Preservation And The Role Of Early Diagenetic Redox In The Early Triassic, Sara B. Pruss, Nicholas J. Tosca, Courcelle Stark Oct 2018

Small Shelly Fossil Preservation And The Role Of Early Diagenetic Redox In The Early Triassic, Sara B. Pruss, Nicholas J. Tosca, Courcelle Stark

Geosciences: Faculty Publications

Minute fossils from a variety of different metazoan clades, collectively referred to as small shelly fossils, represent a distinctive taphonomic mode that is most commonly reported from the Cambrian Period. Lower Triassic successions of the western United States, deposited in the aftermath of the end-Permian mass extinction, provide an example of small shelly style preservation that significantly post-dates Cambrian occurrences. Glauconitized and phosphatized echinoderms and gastropods are preserved in the insoluble residues of carbonates from the Virgin Limestone Member of the Moenkopi Formation. Echinoderm plates, spines and other skeletal elements are preserved as stereomic molds; gastropods are preserved as steinkerns. …


Laguna Madre Estuary Program Environmental Strategic Plan - Final Report, Kim D. Jones, Lucy Camacho, T. Sinha, Omar Al-Qudah, Hudson R. Deyoe, Augusto Sanchez Gonzalez, Jungseok Ho, Javier Guerrero Sep 2018

Laguna Madre Estuary Program Environmental Strategic Plan - Final Report, Kim D. Jones, Lucy Camacho, T. Sinha, Omar Al-Qudah, Hudson R. Deyoe, Augusto Sanchez Gonzalez, Jungseok Ho, Javier Guerrero

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

The goal of this effort is to establish a framework of fundamental information and critical ideas to serve as a basis to assist in supporting legislation to found the 29th National Estuary Program for the Laguna Madre of the Gulf coast of Texas.

The National Estuary Program (NEP) was established by the Clean Water Act Amendments of 1987 (Section 320) to protect nationally significant estuaries threatened by development, pollution and overuse. The U.S. Environmental Protection Agency administers the NEP. The Corpus Christi Bay NEP (now the Coastal Bend Bays and Estuary Program) was among the last estuaries accepted into the …


Marine Threats Overlap Key Foraging Habitat For Two Imperiled Sea Turtle Species In The Gulf Of Mexico, Kristen M. Hart, Autumn R. Iverson, Ikuko Fujisaki, Margaret M. Lamont, David Bucklin, Donna J. Shaver Sep 2018

Marine Threats Overlap Key Foraging Habitat For Two Imperiled Sea Turtle Species In The Gulf Of Mexico, Kristen M. Hart, Autumn R. Iverson, Ikuko Fujisaki, Margaret M. Lamont, David Bucklin, Donna J. Shaver

United States Geological Survey: Staff Publications

Effective management of human activities affecting listed species requires understanding both threats and animal habitat-use patterns. However, the extent of spatial overlap between high-use foraging areas (where multiple marine species congregate) and anthropogenic threats is not well-known. Our modeling approach incorporates data on sea turtle spatial ecology and a suite of threats in the Gulf of Mexico to identify and map “hot spots” of threats to two imperiled turtle species. Of all 820 “high” threats grid cells, our tracked turtles foraged at least 1 day in 77% of them. Although threat data were not available outside the U.S. Exclusive Economic …


Using Satellite Remote Sensing To Study The Impact Of Climate And Anthropogenic Changes In The Mesopotamian Marshlands, Iraq, Reyadh Albarakat, Venkat Lakshmi, Compton J. Tucker Sep 2018

Using Satellite Remote Sensing To Study The Impact Of Climate And Anthropogenic Changes In The Mesopotamian Marshlands, Iraq, Reyadh Albarakat, Venkat Lakshmi, Compton J. Tucker

Faculty Publications

The Iraqi Marshes in Southern Iraq are considered one of the most important wetlands in the world. From 1982 to the present, their area has varied between 10,500 km2 and 20,000 km2. The marshes support a variety of plants, such as reeds and papyrus, and are home to many species of birds. These marshes are Al-Hammar, Central or Al-Amarah, and Al-Huwaiza. Freshwater supplies to the marshes come from the Tigris and Euphrates rivers in Iraq and from the Karkha River from Iran. For this analysis, we used the Land Long-Term Data Record Version 5 (LTDR V5) Normalized …


The 2015 Landslide And Tsunami In Taan Fiord, Alaska, Bretwood Higman, Breanyn Macinnes, Colin Bloom Sep 2018

The 2015 Landslide And Tsunami In Taan Fiord, Alaska, Bretwood Higman, Breanyn Macinnes, Colin Bloom

All Faculty Scholarship for the College of the Sciences

Glacial retreat in recent decades has exposed unstable slopes and allowed deep water to extend beneath some of those slopes. Slope failure at the terminus of Tyndall Glacier on 17 October 2015 sent 180 million tons of rock into Taan Fiord, Alaska. The resulting tsunami reached elevations as high as 193 m, one of the highest tsunami runups ever documented worldwide. Precursory deformation began decades before failure, and the event left a distinct sedimentary record, showing that geologic evidence can help understand past occurrences of similar events, and might provide forewarning. The event was detected within hours through automated seismological …


Little Lasting Impact Of The Paleocene-Eocene Thermal Maximum On Shallow Marine Molluscan Faunas, Linda Ivany, Carlie Pietsch, John Handley, Rowan Lockwood, Warren Allmon, Jocelyn Sessa Sep 2018

Little Lasting Impact Of The Paleocene-Eocene Thermal Maximum On Shallow Marine Molluscan Faunas, Linda Ivany, Carlie Pietsch, John Handley, Rowan Lockwood, Warren Allmon, Jocelyn Sessa

Faculty Publications

Global warming, acidification, and oxygen stress at the Paleocene-Eocene Thermal Maximum (PETM) are associated with severe extinction in the deep sea and major biogeographic and ecologic changes in planktonic and terrestrial ecosystems, yet impacts on shallow marine macrofaunas are obscured by the incompleteness of shelf sections. We analyze mollusk assemblages bracketing (but not including) the PETM and find few notable lasting impacts on diversity, turnover, functional ecology, body size, or life history of important clades. Infaunal and chemosymbiotic taxa become more common, and body size and abundance drop in one clade, consistent with hypoxia-driven selection, but within-clade changes are not …


Report Of Community Conversations About Gender Roles In Livestock, Mamusha Lemma, Wole Kinati, Annet Mulema, Zekarias Bassa, Abiro Tigabe, Hiwot Desta, Mesfin Mekonnen, Tadious Asfaw Sep 2018

Report Of Community Conversations About Gender Roles In Livestock, Mamusha Lemma, Wole Kinati, Annet Mulema, Zekarias Bassa, Abiro Tigabe, Hiwot Desta, Mesfin Mekonnen, Tadious Asfaw

Daugherty Water for Food Global Institute: Faculty Publications

The International Livestock Research Institute (ILRI) and the International Center for Research in the Dry Areas (ICARDA) gender and animal health teams facilitated community conversations (CCs) about gender roles in livestock husbandry in three districts in the Southern Nations, Nationalities and Peoples Region (SNNPR) and Amhara region from 30 May–07 June 2018. These dictricts were: Doyogena (Hawora Arara and Ancha Sadicha kebeles) of SNNPR from 30 and 31 May; and Menz Gera district (Sine Amba kebele) and Menz Mama district (Key Afer kebele) of Amhara from June 6–7. In Doyogena, the team held the conversations in farmer training centres (FTCs) …


Impact Of Climate Change On The Transition Of Neanderthals To Modern Humans In Europe, Michael Staubwasser, Virgil Drăgușin, Bogdan P. Onac, Sergey Assonov, Vasile Ersek, Dirk L. Hoffman, Daniel Veres Sep 2018

Impact Of Climate Change On The Transition Of Neanderthals To Modern Humans In Europe, Michael Staubwasser, Virgil Drăgușin, Bogdan P. Onac, Sergey Assonov, Vasile Ersek, Dirk L. Hoffman, Daniel Veres

School of Geosciences Faculty and Staff Publications

Two speleothem stable isotope records from East-Central Europe demonstrate that Greenland Stadial 12 (GS12) and GS10—at 44.3–43.3 and 40.8–40.2 ka—were prominent intervals of cold and arid conditions. GS12, GS11, and GS10 are coeval with a regional pattern of culturally (near-)sterile layers within Europe’s diachronous archeologic transition from Neanderthals to modern human Aurignacian. Sterile layers coeval with GS12 precede the Aurignacian throughout the middle and upper Danube region. In some records from the northern Iberian Peninsula, such layers are coeval with GS11 and separate the Châtelperronian from the Aurignacian. Sterile layers preceding the Aurignacian in the remaining Châtelperronian domain are coeval …


The Geotraces Intermediate Data Product 2017, R. Schlitzer, Lauren Kipp Aug 2018

The Geotraces Intermediate Data Product 2017, R. Schlitzer, Lauren Kipp

School of Earth & Environment Departmental Research

The GEOTRACES Intermediate Data Product 2017 (IDP2017) is the second publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2016. The IDP2017 includes data from the Atlantic, Pacific, Arctic, Southern and Indian oceans, with about twice the data volume of the previous IDP2014. For the first time, the IDP2017 contains data for a large suite of biogeochemical parameters as well as aerosol and rain data characterising atmospheric trace element and isotope (TEI) sources. The TEI data in the IDP2017 are quality controlled by careful assessment of intercalibration results and …


Global Dynamics Of A Mutualism–Competition Model With One Resource And Multiple Consumers, Yuanshi Wang, Hong Wu, Donald L. Deangelis Aug 2018

Global Dynamics Of A Mutualism–Competition Model With One Resource And Multiple Consumers, Yuanshi Wang, Hong Wu, Donald L. Deangelis

United States Geological Survey: Staff Publications

Recent simulation modeling has shown that species can coevolve toward clusters of coexisting consumers exploiting the same limiting resource or resources, with nearly identical ratios of coefficients related to growth and mortality. This paper provides a mathematical basis for such as situation; a full analysis of the global dynamics of a new model for such a class of n-dimensional consumer–resource system, in which a set of consumers with identical growth to mortality ratios compete for the same resource and in which each consumer is mutualistic with the resource. First, we study the system of one resource and two consumers. …


Ancient Convergent Losses Of Paraoxonase 1 Yield Potential Risks For Modern Marine Mammals, Wynn K. Meyer, Jerrica Jamison, Rebecca Richter, Stacy E. Woods, Raghavendran Partha, Amanda Kowalczyk, Charles Kronk, Maria Chikina, Robert K. Bonde, Daniel E. Crocker, Joseph Gaspard, Janet M. Lanyon, Judit Marsillach, Clement E. Furlong, Nathan L. Clark Aug 2018

Ancient Convergent Losses Of Paraoxonase 1 Yield Potential Risks For Modern Marine Mammals, Wynn K. Meyer, Jerrica Jamison, Rebecca Richter, Stacy E. Woods, Raghavendran Partha, Amanda Kowalczyk, Charles Kronk, Maria Chikina, Robert K. Bonde, Daniel E. Crocker, Joseph Gaspard, Janet M. Lanyon, Judit Marsillach, Clement E. Furlong, Nathan L. Clark

United States Geological Survey: Staff Publications

Mammals diversified by colonizing drastically different environments, with each transition yielding numerous molecular changes, including losses of protein function. Though not initially deleterious, these losses could subsequently carry deleterious pleiotropic consequences. We have used phylogenetic methods to identify convergent functional losses across independent marine mammal lineages. In one extreme case, Paraoxonase 1 (PON1) accrued lesions in all marine lineages, while remaining intact in all terrestrial mammals. These lesions coincide with PON1 enzymatic activity loss in marine species’ blood plasma. This convergent loss is likely explained by parallel shifts in marine ancestors’ lipid metabolism and/or bloodstream oxidative environment affecting PON1’s role …


Influence Of Cover Crop Species On Soil Physical Properties In A Corn-Soybean Rotation, Addison D. Jacobs Aug 2018

Influence Of Cover Crop Species On Soil Physical Properties In A Corn-Soybean Rotation, Addison D. Jacobs

Student Theses and Dissertations

As crop land decreases and population increases, soil quality is becoming a concern. Utilizing cover crops in cropping systems could improve soil quality. This study examined 16 treatments of single-species cover crops, cover crop mixes, and two control treatments on a silt-loam soil, in a corn (Zea mays L.) - soybean (Glycine max L. Merr.) crop rotation under no-tillage, to determine their effect on soil physical properties. Cover crop biomass differed (p<0.10) among treatments and produced a maximum of 15.6 Mg ha-1 of biomass in the crimson clover treatment. Water infiltration rates increased as much as 282% in the complete-mix treatment compared to the fallow control. Differences in infiltration rates due to cover crop species were shown in two-years. However, these results suggest that it may take more time for cover crops to affect change in bulk density and aggregate stability.


Internal Parasites Of The Two Subspecies Of The West Indian Manatee Trichechus Manatus, Heidi Wyrosdick, Alycia Chapman, Antonio A. Mignucci-Giannoni, Carla I. Rivera-Pérez, Robert K. Bonde Aug 2018

Internal Parasites Of The Two Subspecies Of The West Indian Manatee Trichechus Manatus, Heidi Wyrosdick, Alycia Chapman, Antonio A. Mignucci-Giannoni, Carla I. Rivera-Pérez, Robert K. Bonde

United States Geological Survey: Staff Publications

The West Indian manatee Trichechus manatus is divided into 2 subspecies: the Antillean (T. m. manatus) and Florida (T. m. latirostris) manatees. This study reports sample prevalence of manatee parasites from populations of these 2 subspecies in different geographical locations. Although necropsy is a valuable diagnostic tool for parasite infections, the need for antemortem diagnostic techniques is important. Fecal samples collected during necropsies of Antillean manatees (n = 3) in Puerto Rico and Florida manatees (n = 10) in Crystal River, Florida, as well as from live-captured Florida manatees (n = 11) were evaluated using centrifugal …


The Evaluation Of Two Different Harvesting 'Topbunch' And 'Hi-Crop' Collards (Brassica Oleracea (L)) Leaves From Plants Grown In A Wiregrass Tunnel House, Edward Sparks, Raymon Shange, Jacquelyn Jackson, Victor Khan, James E. Currington, Ramble Ankumah, Nathaniel Ellison, George X. Hunter Jr., Jeffery L. Moore Aug 2018

The Evaluation Of Two Different Harvesting 'Topbunch' And 'Hi-Crop' Collards (Brassica Oleracea (L)) Leaves From Plants Grown In A Wiregrass Tunnel House, Edward Sparks, Raymon Shange, Jacquelyn Jackson, Victor Khan, James E. Currington, Ramble Ankumah, Nathaniel Ellison, George X. Hunter Jr., Jeffery L. Moore

Professional Agricultural Workers Journal

A study was conducted to determine if a 100% or 50% harvest intensity of ‘Topbunch’ collards leaves could be a recommended practice for Tunnel House producers. The experiment was conducted as a split-plot design with harvest dates as main plots, and harvesting intensity of 100% or 50% of leaves as sub-plots. All treatments were replicated three times, drip irrigated, and fertilized according to soil test recommendations. The results showed significant interactions between harvest methods and dates for number and weight of leaves harvested. There were also significant differences for the weight of leaves harvested and numbers. The leaf recovery rates …


The Effect Of Two Different Harvesting Methods On The Yield Of 'Topbunch' And 'Hi-Crop' Collards (Brassica Oleracea (L)) When Grown In A Wiregrass Tunnel House, Veronica E. Walton, Raymon Shange, Melissa Johnson, Edward Sparks, Victor Khan, James E. Currington, Ramble Ankumah, Nathaniel Ellison, George X. Hunter Jr., Jeffery L. Moore Aug 2018

The Effect Of Two Different Harvesting Methods On The Yield Of 'Topbunch' And 'Hi-Crop' Collards (Brassica Oleracea (L)) When Grown In A Wiregrass Tunnel House, Veronica E. Walton, Raymon Shange, Melissa Johnson, Edward Sparks, Victor Khan, James E. Currington, Ramble Ankumah, Nathaniel Ellison, George X. Hunter Jr., Jeffery L. Moore

Professional Agricultural Workers Journal

A study was conducted to determine if 100% or 50% harvesting of collard leaves was a suitable recommendation for Tunnel House producers. The experiment was conducted as a split-split plot design with varieties as the main plots, harvesting 100% or 50% of leaves as the sub-plots, and days after transplanting as the subplots. All treatments were replicated three times, drip irrigated, and fertilized according to soil test recommendations. The results showed significant interactions between varieties and method of harvest, for leaf numbers and weight. Conversely, the varieties showed significant differences for yield but not leaf numbers. Both varieties showed significant …


Effects Of Volcanicity In Iceland, Lilian Njoki Ng'ang'a Aug 2018

Effects Of Volcanicity In Iceland, Lilian Njoki Ng'ang'a

Student Works

Iceland is greatly known for its volcanicity as there are several eruptions that have occurred over the years. The country’s volcanology is due to its location on the Mid-Atlantic Ridge, which is a divergent tectonic boundary (Promote Iceland, n.d.). Due to this, the country is known to be responsible for a third of all the fresh lava on earth (Marteinn, 2018).

This research provides a deep dive into the effects of volcanicity and how the Icelandic people have adapted to it. The methods used to collect data for this research were secondary sources and interviews. It was evident that the …


Quantifying Plant Soluble Protein And Digestible Carbohydrate Content, Using Corn (Zea Mays) As An Exemplar, Carrie A. Deans, Gregory A. Sword, Paul A. Lenhart, Eric Burkness, William D. Hutchison, Spencer T. Behmer Aug 2018

Quantifying Plant Soluble Protein And Digestible Carbohydrate Content, Using Corn (Zea Mays) As An Exemplar, Carrie A. Deans, Gregory A. Sword, Paul A. Lenhart, Eric Burkness, William D. Hutchison, Spencer T. Behmer

Entomology Faculty Publications

Elemental data are commonly used to infer plant quality as a resource to herbivores. However, the ubiquity of carbon in biomolecules, the presence of nitrogen-containing plant defensive compounds, and variation in species-specific correlations between nitrogen and plant protein content all limit the accuracy of these inferences. Additionally, research focused on plant and/or herbivore physiology require a level of accuracy that is not achieved using generalized correlations. The methods presented here offer researchers a clear and rapid protocol for directly measuring plant soluble proteins and digestible carbohydrates, the two plant macronutrients most closely tied to animal physiological performance. The protocols combine …


Serum Proteins In Healthy And Diseased Florida Manatees (Trichechus Manatus Latirostris), J.W. Harvey, K.E. Harr, D. Murphy, M.T. Walsh, M. De Wit, R.K. Bonde Aug 2018

Serum Proteins In Healthy And Diseased Florida Manatees (Trichechus Manatus Latirostris), J.W. Harvey, K.E. Harr, D. Murphy, M.T. Walsh, M. De Wit, R.K. Bonde

United States Geological Survey: Staff Publications

A major goal of this study was to determine whether serum protein fractions of healthy Florida manatees differ with age, sex, or living environments (wild versus housed). A second goal was to determine which serum protein fractions vary in diseased versus healthy manatees. Serum protein fractions were determined using agarose gel electrophoresis. Healthy adults had slightly higher total serum protein and total globulin concentrations than younger animals. This largely resulted from an increase in gamma globulins with age. Total serum protein, albumin, alpha-1 globulin, beta globulin, and total globulin concentrations were slightly higher in housed manatees compared to wild manatees, …


Visualization Of Geospatial Data As An Analytical And Educational Tool, Richard A. Vu Aug 2018

Visualization Of Geospatial Data As An Analytical And Educational Tool, Richard A. Vu

STAR Program Research Presentations

World Wind is an open-source API developed for Java, Android, and browsers that is designed to visualize and interact with geospatial data. The Web World Wind client is composed of four major components: the HTML template, the globe, geospatial features, and application features. The template was implemented using Bootstrap and hosts the globe provided by World Wind. This globe draws its data from multiple imagery sources, including the Open Geospatial Consortium (OGC) Web Map Service and Web Map Tile Service. This enables the application to perform and visualize complex calculations with multiple types of data such as weather and terrain. …


The Geotraces Intermediate Data Product 2017, Conwaygeotraces, Tim M. Conway Aug 2018

The Geotraces Intermediate Data Product 2017, Conwaygeotraces, Tim M. Conway

School of Geosciences Faculty and Staff Publications

The GEOTRACES Intermediate Data Product 2017 (IDP2017) is the second publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2016. The IDP2017 includes data from the Atlantic, Pacific, Arctic, Southern and Indian oceans, with about twice the data volume of the previous IDP2014. For the first time, the IDP2017 contains data for a large suite of biogeochemical parameters as well as aerosol and rain data characterising atmospheric trace element and isotope (TEI) sources. The TEI data in the IDP2017 are quality controlled by careful assessment of intercalibration results …


Flow Regime Influences On Stream And Riparian Soil Carbon Dynamics In The Ozark Highlands And Boston Mountains Of Arkansas, Allyn Dodd Aug 2018

Flow Regime Influences On Stream And Riparian Soil Carbon Dynamics In The Ozark Highlands And Boston Mountains Of Arkansas, Allyn Dodd

Graduate Theses and Dissertations

The natural flow regime exerts primacy over lotic ecosystem patterns and processes. However, little work has examined the influence of flow regime on instream and riparian carbon (C) dynamics in minimally-impacted, temperate forested systems. To date, most research efforts have focused on characterizing C movement and transformations across biomes and land use categories; however, flow regime represents an overlooked, finer level of detail that may drive differences in ecosystem function. My dissertation objective was to measure C fixation and movement within and across multiple environmental spheres (e.g. within stream channels, between stream surfaces and the atmosphere, and from riparian soils …


Stratigraphic Evaluation Of The St. Joe-Boone Boundary Interval, Kinderhookian-Osagean Series, Lower Mississippian System, Tri-State Region, Southern Midcontinent, Forrest Dalton Mcfarlin Aug 2018

Stratigraphic Evaluation Of The St. Joe-Boone Boundary Interval, Kinderhookian-Osagean Series, Lower Mississippian System, Tri-State Region, Southern Midcontinent, Forrest Dalton Mcfarlin

Graduate Theses and Dissertations

The Lower Mississippian interval comprises a single, third-order, eustatic cycle subdivided lithostratigraphically into the St. Joe Limestone (Hopkins 1893) and overlying Boone Formation (Branner 1891, Simonds 1891) with type areas in northern Arkansas. Coeval, homotaxial limestones occur in adjacent southwestern Missouri and northeastern Oklahoma. Missouri formation names for the St. Joe interval are recognized in Arkansas as members (ascending order): Bachelor, Compton, Northview, Pierson. The Boone interval in Missouri is represented by the (ascending order): Reeds Spring, Elsey, Burlington-Keokuk undifferentiated, but utilization of those names in Arkansas is problematic. in northern Arkansas, the Boone Formation is subdivided into informal lower …


Estimating Watershed Mercury Contribution To Lake Fort Smith State Park, Arkansas, Usa, William Miles Harmon Aug 2018

Estimating Watershed Mercury Contribution To Lake Fort Smith State Park, Arkansas, Usa, William Miles Harmon

Graduate Theses and Dissertations

Mercury contamination associated with human activities poses global human health and environmental risks. A fish-consumption advisory has been in effect at Lake Fort Smith in central west Arkansas for more than a decade due to observed methylmercury concentrations in fish tissue. Lake Fort Smith is an important municipal drinking water supply and recreational resource. Water samples from the majority contributing tributary stream, Frog Bayou creek, were collected periodically, under differing hydrologic conditions in order to quantify the allochthonous mercury load delivered to the lake. Temperature, specific conductance, and turbidity data were collected and used to estimate dissolved organic carbon, methylmercury …


Comparative Microbial Community Dynamics In A Karst Aquifer System And Proximal Surface Stream In Northwest Arkansas, Josue Rodriguez Aug 2018

Comparative Microbial Community Dynamics In A Karst Aquifer System And Proximal Surface Stream In Northwest Arkansas, Josue Rodriguez

Graduate Theses and Dissertations

Northwest Arkansas has well-developed karst systems, with numerous sinking streams and springs. Karst conduits make it easy for contaminants to enter groundwater systems, degrading the water quality and destroying fragile karst ecosystems. With the increase of urbanization, potential threats in the form of fecal contamination may prove to be more of a problem. The purpose of this research is to compare the difference between microbial communities within two different settings, a karst aquifer and a surface stream. The microbial communities within Blowing Spring Cave and Little Sugar Creek were detected and identified in water and sediment samples. Samples were also …


Seismic Structure Near The Mariana Trench And Deep Earthquake Triggering In The Tonga Flat Slab, Chen Cai Aug 2018

Seismic Structure Near The Mariana Trench And Deep Earthquake Triggering In The Tonga Flat Slab, Chen Cai

Arts & Sciences Graduate Student Theses and Dissertations

This dissertation utilizes multiple techniques of earthquake location and seismic tomography to investigate deep seismicity in the Tonga flat slab region and the upper mantle structure of the Mariana subduction zone. I study the rupture property and aftershock distributions of the largest earthquake ever recorded in the Tonga flat slab region, defined by scattered seismicity and velocity anomalies. These, along with background seismicity, regional 3-D seismic velocity model and tectonic reconstructions of relict Vitiaz subduction zone, suggest the earthquakes are occurring in the final portion of the slab subducted at the now inactive Vitiaz trench. The associated Coulomb stress change …


Improvement Of Soil Structure Through Organic Crop Management, Conservation Tillage And Grass-Clover Ley, Viviana Loaiza Puerta, Engil Isadora Pujol Pereira, Raphaël Wittwer, Marcel G. A. Van Der Heijden, Johan Six Aug 2018

Improvement Of Soil Structure Through Organic Crop Management, Conservation Tillage And Grass-Clover Ley, Viviana Loaiza Puerta, Engil Isadora Pujol Pereira, Raphaël Wittwer, Marcel G. A. Van Der Heijden, Johan Six

School of Earth, Environmental, & Marine Sciences Faculty Publications

Highlights

  • Organic crop management combined with reduced tillage improved soil structure.
  • The ley period improved soil structure for conventional intensive tillage.
  • The ley period increased total carbon in organic crop management at 0–6 cm soil depth.

Abstract

Conventional intensive tillage is a widespread soil management practice that controls weeds and promotes nutrient mineralization at the expense of a degraded soil structure and soil carbon (C) loss. Alternative soil management practices such as no tillage, reduced tillage and temporary leys, however, can minimize the negative effects of intensive tillage on soil structure. To improve understanding of these management practices on …


Managing Herbicide Resistance: Listening To The Perspectives Of Practitioners. Procedures For Conducting Listening Sessions And An Evaluation Of The Process, Jill Schroeder, Michael Barrett, David R. Shaw, Amy B. Asmus, Harold Coble, David Ervin, Raymond A. Jussaume Jr., Micheal D. K. Owen, Ian Burke, Cody F. Creech, A. Stanley Culpepper, William S. Curran, Darrin M. Dodds, Todd A. Gaines, Jeffrey L. Gunsolus, Bradley D. Hanson, Prashant Jha, Annie E. Klodd, Andrew R. Kniss, Ramon G. Leon, Sandra Mcdonald, Don W. Morishita, Brian J. Schutte, Christy L. Sprague, Phillip W. Stahlman, Larry E. Steckel, Mark J. Vangessel Aug 2018

Managing Herbicide Resistance: Listening To The Perspectives Of Practitioners. Procedures For Conducting Listening Sessions And An Evaluation Of The Process, Jill Schroeder, Michael Barrett, David R. Shaw, Amy B. Asmus, Harold Coble, David Ervin, Raymond A. Jussaume Jr., Micheal D. K. Owen, Ian Burke, Cody F. Creech, A. Stanley Culpepper, William S. Curran, Darrin M. Dodds, Todd A. Gaines, Jeffrey L. Gunsolus, Bradley D. Hanson, Prashant Jha, Annie E. Klodd, Andrew R. Kniss, Ramon G. Leon, Sandra Mcdonald, Don W. Morishita, Brian J. Schutte, Christy L. Sprague, Phillip W. Stahlman, Larry E. Steckel, Mark J. Vangessel

Plant and Soil Sciences Faculty Publications

Seven half-day regional listening sessions were held between December 2016 and April 2017 with groups of diverse stakeholders on the issues and potential solutions for herbicide-resistance management. The objective of the listening sessions was to connect with stakeholders and hear their challenges and recommendations for addressing herbicide resistance. The coordinating team hired Strategic Conservation Solutions, LLC, to facilitate all the sessions. They and the coordinating team used in-person meetings, teleconferences, and email to communicate and coordinate the activities leading up to each regional listening session. The agenda was the same across all sessions and included small-group discussions followed by reporting …