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Articles 6361 - 6390 of 9408
Full-Text Articles in Entire DC Network
Geochemical Analysis Of Surface Materials Surrounding The Bautsch-Gray Mine Superfund Site Near Galena, Illinois, Ryan Plath
Geology: Student Scholarship & Creative Works
The Bautsch-Gray zinc and lead mine, near Galena, IL, was in operation from the early 1900s until closing in 1975. The mine’s tailings pile has documented elevated lead and zinc concentrations in the surface materials surrounding the site. Numerous floods have caused contaminated sediment to migrate off the mine tailings pile, across Blackjack Road and into an outwash basin, and towards Smallpox Creek. Since this site was designated an EPA priority list Superfund site in 2010, the EPA has conducted numerous remediation efforts. This study attempts to develop a better understanding of the contamination within the soils of the outwash …
Stable Isotopes As A Tool To Characterize Carbon Cycling And Develop Hydrologic Budgets In Mantled Karst Settings, Katherine Knierim
Stable Isotopes As A Tool To Characterize Carbon Cycling And Develop Hydrologic Budgets In Mantled Karst Settings, Katherine Knierim
Graduate Theses and Dissertations
Isotopes of water (δ2H/δ18O), carbon dioxide (δ13C-CO2), and dissolved inorganic carbon (δ13C-DIC) were used to explore water quality, trace carbon cycling, and quantify recharge sources through mantled karst and into Blowing Spring Cave (BSC). Of the possible sources of contamination in the BSC recharge area, septic-tank effluent was hypothesized to degrade water quality at the spring outlet of BSC because of the dominance of septic tanks for waste treatment, unsuitable topography and soil for septic-tank absorption fields, increased nitrate and chloride concentrations concomitant with increased urbanization, and increased Escherichia coli with discharge. Carbon cycling between the soil and BSC was …
Methane Emissions From Direct-Seeded, Delayed-Flood Rice Grown On A Clay Soil, Alden Daniel Smartt
Methane Emissions From Direct-Seeded, Delayed-Flood Rice Grown On A Clay Soil, Alden Daniel Smartt
Graduate Theses and Dissertations
Due to the production of methane (CH4) under flooded-soil conditions, rice (Oryza sativa L.) cultivation is a major contributor to agricultural CH4 emissions. Studies examining CH4 emissions from rice have only recently been initiated in Arkansas and no data have been collected from rice produced on clay soils in Arkansas. Therefore, research was conducted in 2012 and 2013 at the Northeast Research and Extension Center in Keiser, Arkansas to examine the factors affecting CH4 emissions from rice produced on a Sharkey clay (very-fine, smectitic, thermic Chromic Epiaquerts). The objectives of this study were to determine: 1) the effect of vegetation …
Carbon Isotope Variations Associated With A Middle Ordovician Karstic Unconformity, Patricia Suzanne Williams
Carbon Isotope Variations Associated With A Middle Ordovician Karstic Unconformity, Patricia Suzanne Williams
UNLV Theses, Dissertations, Professional Papers, and Capstones
Large negative carbon isotope (δ13C) excursions have been documented from late Neoproterozoic-Paleozoic successions. These δ13C excursions have been widely used for regional and global stratigraphic correlation, particularly in strata with limited paleontological and radiometric age controls. Recent studies, however, argued that some negative δ13C excursions from stratigraphic record may have been resulted from meteoric/burial diagenesis, which commonly shifts both carbon and oxygen isotopes toward lower values. Testing the diagenetic origin of δ13C excursions in stratigraphic successions without independent stratigraphic framework has been difficult because it evolves into circular arguments about stratigraphic completeness …
Going With The Flow Or Against The Grain? The Promise Of Vegetation For Protecting Beaches, Dunes, And Barrier Islands From Erosion, Rusty A. Feagin, Jens Figlus, Julie C. Zinnert, Jake Sigren, Marisa L. Martínez, Rodolfo Silva, William K. Smith, Ashley Cox, Daniel Cox, Donald R. Young, Gregory A. Carter
Going With The Flow Or Against The Grain? The Promise Of Vegetation For Protecting Beaches, Dunes, And Barrier Islands From Erosion, Rusty A. Feagin, Jens Figlus, Julie C. Zinnert, Jake Sigren, Marisa L. Martínez, Rodolfo Silva, William K. Smith, Ashley Cox, Daniel Cox, Donald R. Young, Gregory A. Carter
Faculty Publications
Coastlines have traditionally been engineered to maintain structural stability and to protect property from storm‐related damage, but their ability to endure will be challenged over the next century. The use of vegetation to reduce erosion on ocean‐facing mainland and barrier island shorelines – including the sand dunes and beaches on these islands – could be part of a more flexible strategy. Although there is growing enthusiasm for using vegetation for this purpose, empirical data supporting this approach are lacking. Here, we identify the potential roles of vegetation in coastal protection, including the capture of sediment, ecological succession, and the building …
Using Kriging, Cokriging, And Gis To Visualize Fe And Mn In Groundwater, Crystal Johnson
Using Kriging, Cokriging, And Gis To Visualize Fe And Mn In Groundwater, Crystal Johnson
Electronic Theses and Dissertations
For aesthetic, economic, and health-related reasons, allowable concentrations of iron (Fe) and manganese (Mn) found present in drinking water are 0.3 mg/L and 0.05 mg/L, respectively. Water samples taken from private drinking wells in the rural communities within Buncombe County, North Carolina contain amounts of these metals in concentrations higher than the suggested limits. This study focused on bedrock geology, elevation, saprolite thickness, and well depth to determine factors affecting Fe and Mn. Using ArcGIS 10.2, spatial trends in Fe and Mn concentrations ranges were visualized, and estimates of the metal concentrations were interpolated to unmonitored areas. Results from this …
Discovering Rock Features With Geophysical Exploration And Archaeological Testing At The Mississippian Pile Mound Site, Upper Cumberland Plateau, Tennessee, Jeremy G. Menzer
Discovering Rock Features With Geophysical Exploration And Archaeological Testing At The Mississippian Pile Mound Site, Upper Cumberland Plateau, Tennessee, Jeremy G. Menzer
Electronic Theses and Dissertations
The Pile Mound survey includes magnetometry paired with targeted ground-penetrating radar (GPR) and electromagnetic induction (EMI) surveys of the mound and testing of associated features over the ca. 6.5 ha site. The GPR survey discovered six rock features (five large rock features within the mound and one marking the outside of the mound). Knowledge of mounds in the Upper Cumberland Plateau (UCP) is lacking—the closest other studied sites are at the Corbin Site, Croley-Evans, Bell Site, and Beasley Mounds, approximately 75 – 100 km away. However, the most similar mound construction is found at Corbin and Cherokee sites, some 175 …
Using Geometric Morphometrics To Differentiate Lower First Molars Of Microtus Species: A Review Of The Clark’S Cave Bone Deposit, Va, Mark Shelleman
Using Geometric Morphometrics To Differentiate Lower First Molars Of Microtus Species: A Review Of The Clark’S Cave Bone Deposit, Va, Mark Shelleman
Electronic Theses and Dissertations
Clark’s Cave contains a large collection of late Pleistocene mammal material. In particular, it contains a sizable amount of Microtus spp. which can be valuable paleoclimate indicators. Identification techniques traditionally used to classify these species have been shown to be unreliable. Recent studies have shown that using geometric morphometric techniques on lower first molars can be more successful. By placing landmarks and running a discriminate analysis on new and previously collected material from the cave, significant differences in Microtus species proportions were found. Specifically, showing the deposit has a larger proportion of M. xanthognathus than previously reported; resulting in a …
Ontogenesis In The Cranium Of Alligator Mississippiensis Based On Disarticulated Cranial Elements, William Henry Harris
Ontogenesis In The Cranium Of Alligator Mississippiensis Based On Disarticulated Cranial Elements, William Henry Harris
Electronic Theses and Dissertations
The American alligator, Alligator mississippiensis, is a large extant archosaur and member of the Order Crocodilia. Crocodilian ontogeny has been studied in great detail, the skull being of particular interest. One aspect of the skull left unstudied is how individual cranial elements change through ontogeny independent of one another. This study observed morphological change in a growth series of 34 specimens of A. mississippiensis from ETSU Vertebrate Paleontology Lab collections. The premaxilla, maxilla, nasal, jugal, frontal, and parietal were analyzed using landmark morphometrics. The frontal, jugal, and parietal showed more allometric growth with the orbits reducing in size posteriorly. …
A Comparison Of Habitat And Geomorphic Changes On East Ship Versus Sand Islands Mississippi, 2007-2014, Carlton Peter Anderson
A Comparison Of Habitat And Geomorphic Changes On East Ship Versus Sand Islands Mississippi, 2007-2014, Carlton Peter Anderson
Master's Theses
ABSTRACT
A COMPARISON OF HABITAT AND GEOMORPHIC CHANGES ON EAST SHIP VERSUS SAND ISLANDS MISSISSIPPI, 2007-2014
by Carlton Peter Anderson
May 2015
The islands of the Mississippi-Alabama (MS-AL) barrier island chain along the micro-tidal northern Gulf of Mexico are highly dynamic coastal features subject to rapid changes in habitat, geomorphology, and elevation by natural and anthropogenic disturbances, such as hurricanes, subsidence, sea-level rise, and dredging activities. The purpose of this study was to compare elevation, total volume, habitat-type coverage, and short-term change between “naturally” formed East Ship Island and “man-made” Sand Island (Disposal-Area 10). This study used a combination of …
Additional Research And Taxonomic Resolution Of Salamanders (Amphibia: Caudata) From The Mio-Pliocene Gray Fossil Site, Tn, Hannah E. Darcy
Additional Research And Taxonomic Resolution Of Salamanders (Amphibia: Caudata) From The Mio-Pliocene Gray Fossil Site, Tn, Hannah E. Darcy
Electronic Theses and Dissertations
The Gray Fossil Site (GFS), a Mio-Pliocene (4.5–7 Ma) locality in the southern Appalachians, boasts the most diverse pre-Pleistocene salamander fauna in North America: Desmognathus sp., Plethodon sp., Notophthalmus sp., a Spelerpinae-type plethodontid, and Ambystoma sp. Because greater taxonomic resolution can result in more precise paleobiological interpretations, additional specimens were studied here. ETMNH 8045, a nearly complete articulated ambystomatid, appears most like Ambystoma maculatum in dentition and vertebral proportions. ETMNH 18219, an isolated vomer, is consistent with modern Pseudotriton and Gyrinophilus in possessing a postdentigerous process and a similar dentigerous row morphology. If these taxa, or species …
Stratigraphic Analysis With Respect To Aggregate Potential In The Duffield Quarry In Gum Log, Arkansas, Brock Evan Langford
Stratigraphic Analysis With Respect To Aggregate Potential In The Duffield Quarry In Gum Log, Arkansas, Brock Evan Langford
Graduate Theses and Dissertations
The crushed stone mining industry is valued at nearly one billion dollars in Arkansas alone. Physical properties of the rock dictate whether or not an area may be suited for the establishment of an aggregate quarry. The Gum Log quarry located 10 miles northeast of Russellville, Arkansas is geographically well situated near areas in need of aggregate material, as well as physically competent rock. The rock mined in Gum Log is located in the Upper Atoka Formation, a Middle Pennsylvanian aged member of the Arkoma Basin. There are five different lithologic facies identifiable in the quarry (Facies 1-5 respectively): A …
Controls On Dissolution Rate Variation At A Pair Of Underflow-Overflow Springs At The Savoy Experimental Watershed, Kiefer Allen Vaughn
Controls On Dissolution Rate Variation At A Pair Of Underflow-Overflow Springs At The Savoy Experimental Watershed, Kiefer Allen Vaughn
Graduate Theses and Dissertations
Physical dissolution experiments and numerical modeling have been used in the past to study limestone dissolution rates. Numerical models have typically used constant dissolution rates, whereas rates in nature vary in time. Limestone tablets allow natural estimation of rates over month time scales, but these rates cannot necessarily be extrapolated to geologic timescales and also do not aid our understanding of short term variability. This study characterizes natural variability in these rates and examines potential causes of that variability from first principles. This may enable more accurate projections of dissolution rates within models. This study combines measurement of physical and …
Utilizing Remote Sensing Imagery To Monitor Vegetation Change Within World Heritage Sites, Mimi Eve Hatzis
Utilizing Remote Sensing Imagery To Monitor Vegetation Change Within World Heritage Sites, Mimi Eve Hatzis
Theses and Dissertations
ABSTRACT
World Heritage sites provide a glimpse into the stories and civilizations of the past. There are currently 1007 unique World Heritage properties with 779 being classified as cultural sites, 197 as natural sites, and 31 falling into the categories of both cultural and natural sites (UNESCO & World Heritage Centre, 1992-2015). However, of these 1007 World Heritage sites, at least 46 are categorized as in danger and this number continues to grow. These unique and irreplaceable sites are exceptional because of their universality. Consequently, since World Heritage sites belong to all the people of the world and provide inspiration …
Influence Of Road Salt Deicers On Anaerobic Respiration And Metal Speciation In Soils, Danielle Dupuis
Influence Of Road Salt Deicers On Anaerobic Respiration And Metal Speciation In Soils, Danielle Dupuis
Honors Theses
Road salt deicers, especially NaCl and CaCl2, are used throughout the world on paved areas during the winter. Previous studies suggest that road salt deicers can alter the biogeochemistry of sediment located near roadways and influence the mobility of heavy metals. The goal of this study is to investigate the influence of CaCl2 on wetland soil biogeochemistry, especially trace metal speciation. Sediment cores were collected in the fall from a freshwater wetland near an urban kettle lake (Asylum Lake, Kalamazoo, MI) and incubated for 100 days in deionized water (control), 5 g/L of CaCl2, or …
The Impact Of Stegastes Planifrons On The Resurgence Of Acropora Cervicornis, Zebulon Martin
The Impact Of Stegastes Planifrons On The Resurgence Of Acropora Cervicornis, Zebulon Martin
Undergraduate Distinction Papers
This study examines resurgent patches of Acropora cervicornis in the “Coral Gardens” back-reef area of Ambergris Caye, Belize. The goal of this study was to understand the carbonate budget and ecosystem dynamics of this successful reef, with an emphasis on the role of Stegastes planifrons (the herbivorous threespot damselfish), on the health of the coral. Benthic survey data from photo-quadrats along six transects were supplemented with counts of S. planifrons, their chimney scars, and sea urchin (Echinometra viridis) to assess their impact on the reef. The data indicate a positive correlation between the density of Stegastes …
Glowing Seashells: Diversity Of Fossilized Coloration Patterns On Coral Reef-Associated Cone Snail (Gastropoda: Conidae) Shells From The Neogene Of The Dominican Republic, Jonathan R. Hendricks
Glowing Seashells: Diversity Of Fossilized Coloration Patterns On Coral Reef-Associated Cone Snail (Gastropoda: Conidae) Shells From The Neogene Of The Dominican Republic, Jonathan R. Hendricks
Faculty Publications
The biology of modern Conidae (cone snails)—which includes the hyperdiverse genus Conus—has been intensively studied, but the fossil record of the clade remains poorly understood, particularly within an evolutionary framework. Here, ultraviolet light is used to reveal and characterize the original shell coloration patterns of 28 species of cone snails from three Neogene coral reef-associated deposits from the Cibao Valley, northern Dominican Republic. These fossils come from the upper Miocene Cercado Fm. and lower Pliocene Gurabo Fm., and range in age from about 6.6-4.8 Ma. Comparison of the revealed coloration patterns with those of extant species allow the taxa to …
The Promise And Peril Of Intensive-Site-Based Ecological Research: Insights From The Hubbard Brook Ecosystem Study, Timothy J. Fahey, Pamela H. Templer, Bruce T. Anderson, John J. Battles, John L. Campbell, Charles T. Driscoll, Anthony R. Fusco, Mark B. Green, Karim-Aly S. Karrim, Nicholas L. Rodenhouse, Lindsay E. Rustad, Paul G. Schaberg, Matthew A. Vadeboncoeur
The Promise And Peril Of Intensive-Site-Based Ecological Research: Insights From The Hubbard Brook Ecosystem Study, Timothy J. Fahey, Pamela H. Templer, Bruce T. Anderson, John J. Battles, John L. Campbell, Charles T. Driscoll, Anthony R. Fusco, Mark B. Green, Karim-Aly S. Karrim, Nicholas L. Rodenhouse, Lindsay E. Rustad, Paul G. Schaberg, Matthew A. Vadeboncoeur
All Materials
Abstract.
Ecological research is increasingly concentrated at particular locations or sites. This trend reflects a variety of advantages of intensive, site-based research, but also raises important questions about the nature of such spatially delimited research: how well does site based research represent broader areas, and does it constrain scientific discovery?We provide an overview of these issues with a particular focus on one prominent intensive research site: the Hubbard Brook Experimental Forest (HBEF), New Hampshire, USA. Among the key features of intensive sites are: long-term, archived data sets that provide a context for new discoveries and the elucidation of ecological mechanisms; …
Chitinozoan Biodiversity In The Ordovician Of Gondwana: An Interval-Free Approach Using The Quantitative Stratigraphic Correlation Program Conop9, Rachel Sales
Honors Theses
The purpose of this study is to examine the biodiversity patterns of a group of fossil organisms called chitinozoans. Chitinozoans are organic-walled, planktonic microfossils that first appear in the Early Ordovician Period (488 million years ago) and diversify rapidly through the Paleozoic Era. The Ordovician Period was a time of great global climate change, and by studying this group of fossil plankton, we hope to better understand how modern plankton, which are the base of the marine food chain, might respond to climate change. We used a method called constrained optimization (CONOP9) to construct a composite range chart of 152 …
Existential Avalanche The Lived Experience Of Climate Change In Dolpo And Mustang, Nepal, Keegan Mcchesney
Existential Avalanche The Lived Experience Of Climate Change In Dolpo And Mustang, Nepal, Keegan Mcchesney
Independent Study Project (ISP) Collection
Himalayan communities stand precariously in an era of phenomenological uncertainty. Climate change is merely a lens through which we may observe and begin to understand such localized modern complexities. The people of the Tarap Valley in Dolpo, Nepal have experienced an increase in avalanches, snow leopard attacks and unpredictable precipitation patterns in recent years. In upper Mustang, Nepal, people have endured the harshest winter in generations and suffered from reduced water access. Environmental, climatic and weather related changes in both Himalayan districts have severely impacted traditional livelihoods and led some to adopt modern means of adaptation. Despite the scientific evidence …
A Survey Of Aquatic Organisms For The Cyanotoxin Beta-Methylamino-L-Alanine (Bmaa), Ian M. Sammler
A Survey Of Aquatic Organisms For The Cyanotoxin Beta-Methylamino-L-Alanine (Bmaa), Ian M. Sammler
OES Theses and Dissertations
Cyanobacteria blooms are increasing globally as a result of eutrophication. Many cyanobacteria are potentially harmful, not only because of the oxygen depleted zones created when they decay, but also because of the toxins they produce. β- Methylamino-L-alanine (BMAA), reportedly produced by many species of cyanobacteria, is a non-proteinogenic amino acid that has been linked to the development of neurodegenerative diseases (amyotrophic lateral sclerosis (ALS) and Alzheimer's) in humans. This study presents results from an assessment of BMAA in cyanobacteria and their grazers from the lower Chesapeake Bay and Lake Erie regions. BMAA was analyzed in samples prepared with the EZ:Faast™ …
Climate Effects On Mammalian Body Size And Grassland Composition Inferred From Late Quaternary Grazers In The Great Plains Of North America, Tom Baldvins
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Several mammalian taxa exhibited a diminution during the Pleistocene-Holocene transition. Two hypotheses have been proposed to explain this phenomenon: (1) human hunting and (2) climate change along with its effects on grasslands. I use stable isotopes from a variety of Quaternary grazing mammals to measure grassland changes following the Last Glacial Maximum (LGM) in Nebraska and to develop a climate proxy to compare with mammalian body size. Results indicate that latest Pleistocene equids and mammoths have δ13C values indicative of a C3 or mixed C3/C4 diet. However, Holocene bison have greatly elevated δ13 …
Morphodynamics Of Mullet Key, West-Central Florida, Emeli Sandoval
Morphodynamics Of Mullet Key, West-Central Florida, Emeli Sandoval
USF Tampa Graduate Theses and Dissertations
Mullet Key is a right angle barrier island located at the mouth of Tampa Bay, west-central Florida. Based on historical shoreline data from 1873, the Gulf (west)-facing section of the beach has been dynamic illustrating large beach advances and retreats of up to 500 m on a decadal scale, while the south (channel)-facing section of the beach has shown to maintain a stable shoreline. This study focuses on the morphodynamics of the Gulf-facing beach. Since the 1920s, most of the Gulf-facing beach has been accreting except at the southern end near the Tampa Bay main channel. However, over the past …
Changes In Spatial Patterns Of Caragana Stenophylla Along A Climatic Drought Gradient On The Inner Mongolian Plateau, Li-Na Xie, Hong-Yu Guo, Christopher A. Gabler, Qing-Fang Li, Cheng-Cang Ma
Changes In Spatial Patterns Of Caragana Stenophylla Along A Climatic Drought Gradient On The Inner Mongolian Plateau, Li-Na Xie, Hong-Yu Guo, Christopher A. Gabler, Qing-Fang Li, Cheng-Cang Ma
School of Earth, Environmental, & Marine Sciences Faculty Publications
Few studies have investigated the influence of water availability on plant population spatial patterns. We studied changes in the spatial patterns of Caragana stenophylla along a climatic drought gradient within the Inner Mongolian Plateau, China. We examined spatial patterns, seed density, “nurse effects” of shrubs on seedlings, transpiration rates and water use efficiency (WUE) of C. stenophylla across semi-arid, arid, and intensively arid zones. Our results showed that patches of C. stenophylla populations shifted from a random to a clumped spatial pattern towards drier environments. Seed density and seedling survival rate of C. stenophylla decreased from the semi-arid zone to …
Functional Anatomy Of The Forelimb Of A New Drepanosaur: Testing Behavioral Models For Extinct Species, Austin Andrus, Dr. Brooks Britt
Functional Anatomy Of The Forelimb Of A New Drepanosaur: Testing Behavioral Models For Extinct Species, Austin Andrus, Dr. Brooks Britt
Journal of Undergraduate Research
Introduction: I recently discovered a new genus of reptile from the Triassic period (roughly 225 million years ago). Reptiles like it are called “drepanosaurs,” and share many unique features such as large claws, unusual, humped shoulder blades, opposable fingers, and prehensile tails. Many of these structures appear to be well-suited for climbing, and the scientific community generally considers drepanosaurs to be arboreal. My new specimen, however, is more complete than previous discoveries have been, and it includes skeletal features that could indicate a digging lifestyle. Digging and climbing are on opposite ends of the behavioral spectrum, so my study seeks …
Nebraska’S Natural Resources Districts: An Assessment Of A Large-Scale Locally Controlled Water Governance Framework, Ann Bleed, Christina Hoffman Babbitt
Nebraska’S Natural Resources Districts: An Assessment Of A Large-Scale Locally Controlled Water Governance Framework, Ann Bleed, Christina Hoffman Babbitt
Daugherty Water for Food Global Institute: Faculty Publications
In 1972 the State of Nebraska created the Natural Resources Districts (NRDs) to consolidate a multitude of single-purpose local natural resource districts into a more comprehensive, holistic, and efficient natural resources governance system. While consolidation and efficiency was important, so was the concept of maintaining local control. Thus, Nebraska rejected the governance framework of a single top-down state agency, preferring to create NRDs that are each governed by a locally elected board. The locally elected governing boards of the NRDs were given broad authorities over many of the state’s natural resources, including groundwater. Such a governance structure was, and to …
Natural And Anthropogenic Processes Contributing To Metal Enrichment In Surface Soils Of Central Pennsylvania, A. M.L. Kraepiel, Ashlee L.D. Dere, E. M. Herndon, Susan L. Brantley
Natural And Anthropogenic Processes Contributing To Metal Enrichment In Surface Soils Of Central Pennsylvania, A. M.L. Kraepiel, Ashlee L.D. Dere, E. M. Herndon, Susan L. Brantley
Geography and Geology Faculty Publications
Metals in soils may positively or negatively affect plants as well as soil micro-organisms and mesofauna, depending on their abundance and bioavailability. Atmospheric deposition and biological uplift commonly result in metal enrichment in surface soils, but the relative importance of these processes is not always resolved. Here, we used an integrated approach to study the cycling of phosphorus and a suite of metals from the soil to the canopy (and back) in a temperate watershed. The behavior of elements in these surface soils fell into three categories. First, Al, Fe, V, Co, and Cr showed little to no enrichment in …
Fossils Of Putative Marine Algae From The Cryogenian Glacial Interlude Of Mongolia, Phoebe A. Cohen, Francis A. Macdonald, Sara Pruss, Emily Matys, Tanja Bosak
Fossils Of Putative Marine Algae From The Cryogenian Glacial Interlude Of Mongolia, Phoebe A. Cohen, Francis A. Macdonald, Sara Pruss, Emily Matys, Tanja Bosak
Geosciences: Faculty Publications
Neoproterozoic carbonate successions provide a new taphonomic window into the diversification of eukaryotes. We report recently discovered macroscopic organic warty sheets (MOWS) in macerates of limestone from the ca. 662-635 Ma Taishir Formation (Tsagaan Olom Group, Mongolia). Sheets are applanate. One surface contains raised ridges and conspicuous, ∼ 100-μm-tall warty protuberances with depressed tops that enclose internal cavities containing cellular structures. The Taishir MOWS may be the remains of unusual bacterial, protistan, or fungal biofilms, or a previously undocumented, extinct taxon. However, multiple lines of evidence including the morphology of warty protuberances and the presence of cellular architecture within protuberances …
Wayne E. Sabbe Arkansas Soil Fertility Studies 2014, Nathan A. Slaton
Wayne E. Sabbe Arkansas Soil Fertility Studies 2014, Nathan A. Slaton
Arkansas Agricultural Experiment Station Research Series
Rapid technological changes in crop management and production require that the research efforts be presented in an expeditious manner. The contributions of soil fertility and fertilizers are major production factors in all Arkansas crops. The studies described within will allow producers to compare their practices with the university’s research efforts. Additionally, soil-test data and fertilizer sales are presented to allow comparisons among years, crops, and other areas within Arkansas.
Microbial Iron Mats At The Mid-Atlantic Ridge And Evidence That Zetaproteobacteria May Be Restricted To Iron-Oxidizing Marine Systems, Jarrod J. Scott, John A. Breier, George W. Luther Iii, David Emerson
Microbial Iron Mats At The Mid-Atlantic Ridge And Evidence That Zetaproteobacteria May Be Restricted To Iron-Oxidizing Marine Systems, Jarrod J. Scott, John A. Breier, George W. Luther Iii, David Emerson
School of Earth, Environmental, & Marine Sciences Faculty Publications
Chemolithoautotrophic iron-oxidizing bacteria play an essential role in the global iron cycle. Thus far, the majority of marine iron-oxidizing bacteria have been identified as Zetaproteobacteria, a novel class within the phylum Proteobacteria. Marine iron-oxidizing microbial communities have been found associated with volcanically active seamounts, crustal spreading centers, and coastal waters. However, little is known about the presence and diversity of iron-oxidizing communities at hydrothermal systems along the slow crustal spreading center of the Mid-Atlantic Ridge. From October to November 2012, samples were collected from rust-colored mats at three well-known hydrothermal vent systems on the Mid-Atlantic Ridge (Rainbow, Trans-Atlantic Geotraverse, and …