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Tapeworms Of Elasmobranchs (Part Ii) A Monograph On The Diphyllidea (Platyhelminthes, Cestoda), Gaines Albert Tyler Ii

Bulletin of the University of Nebraska State Museum (1924–2023)

The main objective of this monograph was a synthesis of the available knowledge on the diversity, systematics, host associations, and biogeography of the Diphyllidea. A thorough review of the literature resulted in the transfer of Diagonobothrium into Diphyllidea as a genus inquirendum. The genus Yogeshwaria was also transferred to Diphyllidea as a synonym of Echinobothrium. Its only species, E. nagabhushani n. comb., is considered to be a species inquirenda. New collections resulted in the description of a new species of Echinobothrium. Type and/or voucher specimens for 32 of 36 valid diphyllidean species (including the new species) …

Evaluating The Biogeochemical Cycle Of Selenium In San Francisco Bay Through Modeling, Shannon L. Meseck, Gregory A. Cutter

OES Faculty Publications

A biogeochemical model was developed to simulate salinity, total suspended material, phytoplankton biomass, dissolved selenium concentrations (selenite, selenate, and organic selenide), and particulate selenium concentrations (selenite + selenate, elemental selenium, and organic selenide) in the San Francisco Bay estuary. Model-generated estuarine profiles of total dissolved selenium reproduced observed estuarine profiles at a confidence interval of 91- 99% for 8 different years under various environmental conditions. The model accurately reproduced the observed dissolved speciation at confidence intervals of 81-98% for selenite, 72-91% for selenate, and 60-96% for organic selenide. For particulate selenium, model-simulated estuarine profiles duplicated the observed behavior of total …

Iron In Ice Cores From Law Dome: A Record Of Atmospheric Iron Deposition For Maritime East Antarctica During The Holocene And Last Glacial Maximum, Ross Edwards, Peter N. Sedwick, Vin Morgan, Claude Boutron

OES Faculty Publications

Total dissolvable iron (TDFe) was measured in sections of ice cores recovered from Law Dome on the coast of Wilkes Land, East Antarctica. These samples include ice dating from the Last Glacial Maximum (LGM), the Last Deglaciation, and the early and mid Holocene as well as samples from the Anthropocene that have been dated with seasonal to annual resolution. Combining our TDFe concentration data with estimates of the ice accumulation rate, we estimate the atmospheric iron deposition for Law Dome and the adjacent Southern Ocean during these periods. Our results indicate that the atmospheric iron deposition flux to this region …

Nitrogen Fixation And Release Of Fixed Nitrogen By Trichodesmium Spp. In The Gulf Of Mexico, Margaret R. Mulholland, Peter W. Bernhardt, Cynthia A. Heil, Deborah A. Bronk, Judith M. O'Neil

OES Faculty Publications

During a 3-yr study in the Gulf of Mexico, we measured dinitrogen (N₂) fixation and nitrogen (N) release by Trichodesmium and compared these rates with water column N demand and the estimated N necessary to support blooms of Karenia brevis, a toxic dinoflagellate that severely affects the West Florida shelf. Net and gross N₂ fixation rates were compared in simultaneous incubations using ¹⁵N₂ uptake and acetylene reduction, respectively. The difference between net and gross N₂ fixation is assumed to be an approximation of the rate of N release. Results demonstrate that Trichodesmium in …

Western Caribbean Sea Surface Temperatures During The Late Quaternary, Matthew W. Schmidt, Maryline J. Vautravers, Howard J. Spero

OES Faculty Publications

[1] Mg/Ca ratios in the planktonic foraminifera Globigerinoides ruber from Colombian Basin core ODP 999A suggest that Caribbean sea surface temperatures ( SSTs) were from 2.1 to 2.7°C colder than the present during the last three glacial maximums. In comparison, faunal derived SSTs ( SIMMAX method) show that August SSTs in the Caribbean varied < 2° over the past 360 kyr, whereas February SSTs varied between 21.0°C and 26.5°C. Changes in the Mg/Ca-SST record contain a strong 23 kyr periodicity, suggesting the Mg/Ca-SST record reflects a warm season weighted SST average rather than an annual mean SST. Combining several dissolution indices, we identify brief periods of decreased carbonate preservation in our record and show that MIS 11 stands out as the most intensive dissolution cycle in the Caribbean over the last 460 kyr. Comparison of Caribbean SST change with a similar estimate of tropical SST variability in the western Pacific over the past 360 kyr reveals shifts in the east-west tropical SST gradient that are coeval with glacial-interglacial climate change and consistent both with a southward migration of the glacial ITCZ and with a glacial El Niño-like mode of tropical circulation.

Past Glacial And Interglacial Conditions In The Arctic Ocean And Marginal Seas - A Review, Dennis A. Darby, Leonid Polyak, Henning A. Bauch

OES Faculty Publications

Past changes in the Arctic Ocean and its marginal seas have been profound, even during the last 10,000 years. Understanding these changes, such as those occurring during the transition from glacial to interglacial climates, are important for research on modern processes, because this knowledge provides a framework and unique perspective in which to view the modern physical and biological processes. This paper discusses our current understanding of past environmental change and processes relative to those currently in progress. Special emphasis is placed on the most recent transition from a glacial state to the modern interglacial conditions.

Modeling Groundwater Denitrification By Ferrous Iron Using Phreeqc, Tedros Tesfay

Theses and Dissertations

Nitrate is one of the most common groundwater contaminants, and ingesting it leads to potential health risks. Denitrification, the only effective process to eliminate nitrate, is limited by the abundance of biologically available electron donors. Thus, understanding the natural denitrification capacity of aquifers, through the analysis of all the major electron donors, is essential.

A better way to estimate groundwater denitrification reactions is to compute the mass balance of the redox sensitive species. The University of North Dakota (UND) denitrification team installed mesocosms (ISMs) to understand the fate of nitrate in field conditions. Accordingly, the team has shown the significant …

Evaluating The Deep-Sea Coral Acanella From Hawaii As A Paleoceanographic Archive, Geraldine Hourigan Lantier

Geology Theses and Dissertations

Deep-sea corals have emerged as potential proxies of changing paleoceanographic properties. The utility of deep-sea corals for the purpose of interpreting paleoclimatic reconstructions is still in the discovery phase. However, long life spans, a relatively stable habitat, and unique growth geometry provide support to the growing body of research that has identified deep-sea corals as indicators of past climate and ocean properties. Two colonies of Acanella were collected from the permanent thermocline at depths between 414 and 437 m in the Makapuu Coral Bed, Oahu, HI in 1997 by submersible. Here I present results from a pilot study of the …

Assessing The Paleoceanographic Potential Of The Coral Montipora Venosa At Fanning Atoll, Central Equatorial Pacific, Alexa Stolorow

Geology Theses and Dissertations

As interest in global climate change increases, so does the need for better and more extensive climate proxies. The central equatorial Pacific has been established as the region with the largest ENSO-related sea surface temperature (SST) and precipitation (PPT) anomalies, which are known to impact global interannual climate variability. To date, the coral genus Porites has been most commonly utilized for coral-based paleo-reconstructions of ENSO and lower frequency phenomena. However, due to questions of biological artifacts in coral, to more fully understand coral-based reconstruction, different coral genera need to be analyzed.
In this study, oxygen (δ18O) and carbon (δ13C) isotopic …

The Effects Of Land Use Changes On Soil Carbon In The Russian Steppe, Andrew M. Ratigliano

Geology Theses and Dissertations

Increasing atmospheric CO2 levels within the past few centuries have led to many studies about the global carbon cycle. An important aspect in balancing the modern global carbon budget revolves around a missing sink of carbon. It is thought that the carbon accumulation in soil may be a significant component in this loss. As changes in land use under natural conditions have increased over the years, it is not well understood how these changes may affect the soil carbon. A useful technique in determining these changes are with the use of archived samples. Within a Russian steppe preserve that has …

Thermochronological Evidence For Neogene Incision Of The Rio Pativilca Canyon, Northern Peru, Matthew James Montario

Geology Theses and Dissertations

The Peruvian Andes have attained modern elevations of ~4000 m. Many peaks along the drainage divide are in excess of 5500 m with ~2-3 km of vertical relief, and canyons cut into the western edge have up to 3.5 km relief. The Rio Pativilica Canyon is cut into a folded Mesozoic marine sequence intruded by granitic rocks of the Coastal Batholith, which are overlain by Tertiary volcanics: this canyon has relief in excess of ~3 km. Based on geomorphological evidence, two episodes of valley incision cut the Puna erosional surface: 1) The Vallé stage, which is characterized by broad valleys …

Divergent Patterns Of Abundance And Age-Class Structure Of Headwater Stream Tadpoles In Burned And Unburned Watersheds, Blake R. Hossack, Paul Stephen Corn, Daniel B. Fagre

United States Geological Survey: Staff Publications

Wildfire is a potential threat to many species with narrow environmental tolerances like the Rocky Mountain tailed frog (Ascaphlls montanlls Mittleman and Myers, 1949), which inhabits a region where the frequency and intensity of wildfires are expected to increase. We compared pre- and post-fire counts of tadpoles in eight streams in northwestem Montana to determine the effects of wildfire on A. montanus. All streams were initially sampled in 2001, 2 years before four of them bumed in a large wildfire, and were resampled during the 2 years follo\ving the fire. Counts of tadpoles were similar in the 1\\'0 …

Effects Of Elevated Atmospheric Co₂ On Scrub-Oak Root Carbon Pools And Soil Microbial Processes, Alisha Lea Pagel Brown

Biological Sciences Theses & Dissertations

The levels of atmospheric CO₂ are rising and this affects the growth of plants and the ecosystems in which they reside. Plants take up additional C from the atmosphere and have potential to sequester C in the soil. I investigated the sequestration of C belowground and the microbial processes that control C retention in the soil. This study was conducted in a Florida scrub-oak ecosystem, where CO₂ levels have been elevated to twice ambient since 1996 in open top chambers. There were eight replicates of ambient CO₂ chambers and eight replicates of twice-ambient CO₂ levels. The …

Plant Paleoecology Of The Late Devonian Red Hill Locality, North-Central Pennsylvania, An Archaeopteris-Dominated Wetland Plant Community And Early Tetrapod Site., Walter L. Cressler Iii

Earth & Space Sciences Faculty Publications

The Late Devonian Red Hill locality in north-central Pennsylvania contains an Archaeopteris-dominated plant fossil assemblage, a diverse fossil fauna, and an extensive sedimentary sequence ideal for investigating the landscapes and biotic associations of the earliest forest ecosystems. Sedimentological analysis of the main plantfossil bearing layer at Red Hill indicates that it was a fl ood-plain pond. A seasonal wet-and-dry climate is indicated by well-developed paleovertisols. The presence of charcoal interspersed with plant fossils indicates that fi res occurred in this landscape.Fires appear to have primarily affected the fern Rhacophyton. The specifi city of the fires, the distribution profi …

Estimating Surface Runoff In The Illinois River Basin For The Management Of Nonpoint-Source Phosphorus Loads, Adam T. Mcclymont, Mary C. Savin, Brian E. Haggard

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

With the growing concern about elevated phosphorus (P) concentrations in regional lakes, rivers, and streams, it is essential to investigate factors contributing to P transport from the landscape. Phosphorus fluxes from nonpoint sources, particularly land applications of poultry litter and other animal manures, are closely related to the amount and production of surface runoff. Daily stream discharge and the software program, Base Flow Index (BFI), were used to estimate the amount and temporal patterns of surface runoff at different locations within the Illinois River Basin, including selected tributaries in northwest Arkansas and northeast Oklahoma. Daily streamflow data from nine U.S. …

A Tool For Estimating Best Management Practice Effectiveness In Arkansas, Katherine R. Merriman, Margaret Gitau, Indrajeet Chaubey

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Increased nutrient and sediment losses from expanding agricultural practices and urban development in Arkansas are important environmental concerns. Best Management Practices (BMPs) are being implemented to lessen the effects of these developments on existing water bodies. There is, however, insufficient scientific base as to the effectiveness of these practices. A number of studies have been conducted in recent years to determine BMP effectiveness. Data from these studies can only be reliably used for the individual site from which they were obtained. When considered collectively, these data comprise quantitative effectiveness over a wide range of conditions and can thus be used …

Evaluation Of Water-Retention Ability Of Eastern Arkansas Prairie And Agricultural Soil, Maria L. Barrenechea, Kristofor R. Brye

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Agricultural land use affects soil physical properties, such as bulk density, water content, organic matter content, and soil structure; all of which in turn affect ecosystem productivity. The objective of this study was to evaluate the effects of: 1) time since aboveground biomass has been removed by haying (i.e., 0 vs. 23 years), and 2) land use (i.e., undisturbed tallgrass prairie vs. cultivated agriculture) on water-retention characteristics in a silt-loam soil of the Grand Prairie region of eastern Arkansas. Soil samples were collected from the 0- to 10-cm depth and were wetted with varying amounts of distillated water to create …

Pelagic Functional Group Modeling: Progress, Challenges And Prospects, Raleigh R. Hood, Edward A. Laws, Robert A. Armstrong, Nicholas R. Bates, Christopher W. Brown, Craig A. Carlson, Fei Chai, Scott C. Doney, Paul G. Falkowski, Richard A. Feely, Marjorie A. M. Friedrichs

CCPO Publications

In this paper, we review the state of the art and major challenges in current efforts to incorporate biogeochemical functional groups into models that can be applied on basin-wide and global scales, with an emphasis on models that might ultimately be used to predict how biogeochemical cycles in the ocean will respond to global warming. We define the term "biogeochemical functional group" to refer to groups of organisms that mediate specific chemical reactions in the ocean. Thus, according to this definition, "functional groups" have no phylogenetic meaning-these are composed of many different species with common biogeochemical functions.

Substantial progress has …

Pyritized Tube Feet In A Protasterid Ophiuroid From The Upper Ordovician Of Kentucky, U.S.A., Alexander Glass

All Faculty Scholarship for the College of the Sciences

A single specimen of the protasterid ophiuroid Protasterina flexuosa from the Kope Formation (Cincinnatian, Upper Ordovician) of Kentucky exhibits three−dimensionally pyritized tube feet. This represents the first report of soft−tissue preservation in an echinoderm from the type−Cincinnatian series. The tube feet are solid and lack all internal structure. They consist of aggregated masses of small euhedral to subhedral pyrite crystals suggesting that pyritization, although decay−induced and mediated, did not necessarily replicate soft−tissues but might instead have formed inside the void−spaces left behind during the decay process. The discovery of pyritized soft−tissue as delicate as ophiuroid tube feet suggests that similar …

Assessing The Potential Impact Of Microbes In The Edwards And Trinity Aquifers Of Central Texas, Kelli Willson Randall

LSU Master's Theses

The Edwards Aquifer in central Texas is one of the largest carbonate aquifers in the United States, supplying nearly two million people with water. The role of microorganisms in the development of deep carbonate aquifers has not been thoroughly investigated. The Edwards Aquifer is composed of a freshwater zone and a sulfidic, saline water zone. Down-well video surveys show an abundance of white filamentous and planktonic biomass floating in the water column, indicating that the saline water may serve as a habitat for microbes and provide a unique opportunity to investigate microbially enhanced deep subsurface karstification. A combination of geochemical …

Caliche As A Geologic Repository For Atmospheric Sulfate, Katie Jane Howell

LSU Master's Theses

Recent studies demonstrate that important information on sulfur source, oxidation pathway, transport pattern, and reaction kinetics of the oxidation reactions of reduced sulfur gases in the atmosphere may be uncovered by measuring multiple sulfur and oxygen isotope compositions of the oxidation product — secondary atmospheric sulfate (SAS). SAS from Earth’s distant past, however, is rarely preserved in the rock record because of its high solubility and small quantity. Caliche, a pedogenic carbonate formed in arid to semi-arid continental settings and common in the geologic record, could serve as a repository for ancient SAS. Two major groups of caliche samples: 1) …

Taphonomic And Sedimentologic Study Of The Cretaceous Tepee Buttes Limestone, Hilary G. Close

Honors Papers

The Tepee Buttes methane seep deposits exist today as topographically defined limestone features in the surrounding Pierre Shale of the Campanian Western Interior Seaway. The present sloping surface has previously been assumed to be indicative of original seep structure, and biofacies were interpreted as roughly ringing a central vent core. Contradictory field observations in this study have prompted a more detailed taphonomic approach to the Tepee Buttes limestone, and certain depositional features such as reworked horizontal shell beds were noted and examined in detail for the first time. The results of a taphonomic and sedimentologic analysis reveal a complex history …

Soil Phosphorus Levels In Residential Lawns And Comparisons Among Four Land Uses In Springfield, Missouri, Timothy R. Davis

Graduate Theses/Dissertations

Eutrophication of surface waters due to high phosphorus (P) concentrations is an important water quality concern in Greene County, Missouri. Phosphorus enrichment has been linked to a variety of non-point sources including runoff from both agricultural and urban land uses. Soil P has been shown to be a source of P in runoff. The differences in soil P among different land uses may provide insight into which land use contributes more P in runoff. This study examines the soil composition, geochemistry and total P concentration of surface soil (0-5cm) in four land uses in Greene County, Missouri. The land uses …

Phytophthora Diseases Of Cutflower Crops, Department Of Agriculture And Food, Western Australia

Bulletins 4000 -

Phytophthora root rot is the most common soil borne disease causing plant death in native cut flower production. It is also a pathogen of exotic cutflower crops such as rose, lily, carnation, proteas and gerbera. The fungus, Phytophthora cinnamomi, the cause of jarrah dieback is the pathogen that first comes to mind when Phytophthora is mentioned. This has one of the widest host ranges of all Phytophthora species, particularly amongst native Australia species. P.nicotianae also has a wide host range, infecting a wide range of exotic, as well as Australian native flower crops. There are also a number of …

Methods To Set Land Salinity Resource Condition Targets For The South West : Case Studies From Australia And New Zealand, Sharon Hu

Resource management technical reports

This Resource Management Technical Report provides background to methods to set targets on land salinity in the South West Natural Resource Management (NRM) region of Western Australia. Case studies from Australia and New Zealand have been reviewed to determine what approaches should be used. Resource Condition Targets (RCTs) are required for land salinity, soil condition and remnant vegetation.

Glacial Deposits, Vol. 34, 2005-2006, Department Of Geography-Geology

Glacial Deposits

Newsletter of the Department of Geography-Geology

Feasibility Analysis Of The Strontium Ratio Obtained From Pennsylvanian Chondricthian Dentary, Cullen John Erbacher

Browse all Theses and Dissertations

This research was undertaken to determine the amount of time between transgressive and regressive sequences. One of the methods used to determine the amount of missing time in an unconformity is the 87Sr / 86Sr ratio. The 87Sr / 86Sr ratio will be high around brackish and freshwater environments while it will be lower in open marine conditions. Limestones and their constituent parts are susceptible to diagenetic processes that can contaminate or obliterate isotope values contained within the rocks. The purpose of this research was to discover if reliable isotope information could be pulled from Pennsylvanian aged shark teeth. Nine …

Diatom Paleolimnological Record Of Holocene Climatic And Environmental Change In The Altai Mountains, Siberia, Karlyn S. Westover, Sherilyn C. Fritz, Tatyana A. Blyakharchuk, Herbert E. Wright

Department of Earth and Atmospheric Sciences: Faculty Publications

The sedimentary diatom records of three shallow lakes in the Altai Mountains, southern Siberia, were examined to assess the nature and timing of Holocene environmental changes. Few paleoenvironmental records, especially reconstructions not based on pollen, have been reported from this region. The lakes differ in elevation, annual precipitation, and catchment vegetation. Diatom assemblages in all lakes were dominated for the entire period of record by small benthic species of Pseudostaurosira Williams & Round, Staurosira Ehrenberg, and Staurosirella Williams & Round. Planktonic taxa only occur in very low abundances (<5%). The most diverse diatom flora was found in Dzhangyskol, which is situated at the lowest elevation within a forested catchment. A lack of detailed information on the ecological preferences of the dominant taxa and the complexity of environmental drivers make direct interpretation of the diatom record difficult. However, other proxies suggest that dramatic shifts in dominance between Staurosira elliptica and Staurosirella pinnata in Grusha Ozero reflect millennial-scale variability …

The Earth All Around Us: Selected Building Stone In Lincoln, Nebraska. A Walking Tour, William J. Wayne

Department of Earth and Atmospheric Sciences: Faculty Publications

Stone has been a primary building material for millennia. Cities, therefore, are treasure troves of earth materials. A wide variety of stones from many places are used for walls, as foundations to support entire buildings, as trim, and more recently as cladding (facing, an overlay). The Earth science teacher can find, in the limited space of an urban environment, a superb collection of stones with which to introduce students to these materials. The surfaces of stones on the outsides of buildings illustrate the durability and the vulnerability of each kind of stone to the local climate. And the history of …

Coupling Between Primary Terrestrial Succession And The Trophic Development Of Lakes At Glacier Bay, Alaska, D. R. Engstrom, Sherilyn C. Fritz

Department of Earth and Atmospheric Sciences: Faculty Publications

The natural eutrophication of lakes is still an accepted concept in limnology, arising as it does from the earliest efforts to classify lakes and place them in an evolutionary sequence. Recent studies of newly formed lakes at Glacier Bay, Alaska, only partially support this idea, and suggest more variable trends in lake trophic development which are under local (catchment-level) control. Here we use sediment cores from several lakes in Glacier Bay National Park to examine the relationship between successional changes in catchment vegetation and trends in water-column nitrogen (a limiting nutrient) and lake primary production. Terrestrial succession at Glacier Bay …