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Articles 15121 - 15150 of 17792
Full-Text Articles in Entire DC Network
Taxonomy Of Quaternary Deep-Sea Ostracods From The Western North Atlantic Ocean, Moriaki Yasuhara, Hisayo Okahashi, Thomas M. Cronin
Taxonomy Of Quaternary Deep-Sea Ostracods From The Western North Atlantic Ocean, Moriaki Yasuhara, Hisayo Okahashi, Thomas M. Cronin
United States Geological Survey: Staff Publications
Late Quaternary sediments from Ocean Drilling Program (ODP) Hole 1055B, Carolina Slope, western North Atlantic (32°47.041’ N, 76°17.179’ W; 1798 m water depth) were examined for deep-sea ostracod taxonomy. A total of 13 933 specimens were picked from 207 samples and c. 120 species were identified. Among them, 87 species were included and illustrated in this paper. Twenty-eight new species are described. The new species are: Ambocythere sturgio, Argilloecia abba, Argilloecia caju, Argilloecia keigwini, Argilloecia robinwhatleyi, Aversovalva carolinensis, Bythoceratina willemvandenboldi, Bythocythere eugeneschornikovi, Chejudocythere tenuis, Cytheropteron aielloi, Cytheropteron demenocali, Cytheropteron didieae, Cytheropteron richarddinglei, Cytheropteron fugu, Cytheropteron guerneti, Cytheropteron richardbensoni, Eucytherura hazeli, …
Paleoceanography Of The Gulf Of Alaska During The Past 15,000 Years: Results From Diatoms, Silicoflagellates, And Geochemistry, John A. Barron, David Bukry, Walter E. Dean, Jason A. Addison, Bruce Finney
Paleoceanography Of The Gulf Of Alaska During The Past 15,000 Years: Results From Diatoms, Silicoflagellates, And Geochemistry, John A. Barron, David Bukry, Walter E. Dean, Jason A. Addison, Bruce Finney
United States Geological Survey: Staff Publications
High-resolution records of diatoms, silicoflagellates, and geochemistry covering the past 15,000 years were studied in three cores from the Gulf of Alaska (GOA). Core EW0408-85JC in an oceanic setting on the Kayak Slope displays a paleoceanographic record similar to that at several locations on the California margin during deglaciation. Biologic productivity as reconstructed using geochemical and microfossil proxies increased abruptly during the Bølling–Alleröd (Bø–Al) warm interval (14.7–12.9 cal ka), declined during the Younger Dryas (YD) cold interval (12.9 to 11.7 cal kyr BP), and rose again during the earliest Holocene. At this site, the record after ~11 cal kyr BP …
A One-Dimensional Heat-Transport Model For Conduit Flow In Karst Aquifers, Andrew J. Long, Patrick C. Gilcrease
A One-Dimensional Heat-Transport Model For Conduit Flow In Karst Aquifers, Andrew J. Long, Patrick C. Gilcrease
United States Geological Survey: Staff Publications
A one-dimensional heat-transport model for conduit flow in karst aquifers is presented as an alternative to two or three-dimensional distributed-parameter models, which are data intensive and require knowledge of conduit locations. This model can be applied for cases where water temperature in a well or spring receives all or part of its water from a phreatic conduit. Heat transport in the conduit is simulated by using a physically-based heat-transport equation that accounts for inflow of diffuse flow from smaller openings and fissures in the surrounding aquifer during periods of low recharge. Additional diffuse flow that is within the zone of …
History Of Wildlife Toxicology, Barnett A. Rattner
History Of Wildlife Toxicology, Barnett A. Rattner
United States Geological Survey: Staff Publications
The field of wildlife toxicology can be traced to
the late nineteenth and early twentieth centuries. Initial
reports included unintentional poisoning of birds from
ingestion of spent lead shot and predator control agents,
alkali poisoning of waterbirds, and die-offs from maritime
oil spills. With the advent of synthetic pesticides in the
1930s and 1940s, effects of DDT and other pesticides were
investigated in free-ranging and captive wildlife. In
response to research findings in the US and UK, and the
publication of Silent Spring in 1962, public debate on the
hazards of pollutants arose and national contaminant
monitoring programs were initiated. …
Climate Trends Of The North American Prairie Pothole Region 1906–2000, Bruce Millett, W. Carter Johnson, Glenn Guntenspergen
Climate Trends Of The North American Prairie Pothole Region 1906–2000, Bruce Millett, W. Carter Johnson, Glenn Guntenspergen
United States Geological Survey: Staff Publications
The Prairie Pothole Region (PPR) is unique to North America. Its millions of wetlands and abundant ecosystem goods and services are highly sensitive to wide variations of temperature and precipitation in time and space characteristic of a strongly continental climate. Precipitation and temperature gradients across the PPR are orthogonal to each other. Precipitation nearly triples from west to east from approximately 300 mm/year to 900 mm/year, while mean annual temperature ranges from approximately 1°C in the north to nearly 10°C in the south. Twentieth-century weather records for 18 PPR weather stations representing 6 ecoregions revealed several trends. The climate generally …
Climate Trends Of The North American Prairie Pothole Region 1906–2000, Bruce Millett, W. Carter Johnson, Glenn R. Guntenspergen
Climate Trends Of The North American Prairie Pothole Region 1906–2000, Bruce Millett, W. Carter Johnson, Glenn R. Guntenspergen
United States Geological Survey: Staff Publications
The Prairie Pothole Region (PPR) is unique to North America. Its millions of wetlands and abundant ecosystem goods and services are highly sensitive to wide variations of temperature and precipitation in time and space characteristic of a strongly continental climate. Precipitation and temperature gradients across the PPR are orthogonal to each other. Precipitation nearly triples from west to east from approximately 300 mm/year to 900 mm/year, while mean annual temperature ranges from approximately 1◦C in the north to nearly 10◦C in the south. Twentieth-century weather records for 18 PPR weather stations representing 6 ecoregions revealed several trends. The climate generally …
Productivity-Diversity Relationships From Chemolithoautotrophically Based Sulfidic Karst Systems, Megan L. Porter, Annette Summers Engel, Thomas C. Kane, Brian K. Kinkle
Productivity-Diversity Relationships From Chemolithoautotrophically Based Sulfidic Karst Systems, Megan L. Porter, Annette Summers Engel, Thomas C. Kane, Brian K. Kinkle
International Journal of Speleology
Although ecosystems thriving in the absence of photosynthetic processes are no longer considered unique phenomena, we have yet to understand how these ecosystems are energetically sustained via chemosynthesis. Ecosystem energetics were measured in microbial mats from active sulfidic caves (Movile Cave, Romania; Frasassi Caves, Italy; Lower Kane Cave, Wyoming, USA; and Cesspool Cave, Virginia, USA) using radiotracer techniques. We also estimated bacterial diversity using 16S rRNA sequences to relate the productivity measurements to the composition of the microbial communities. All of the microbial communities investigated were dominated by chemolithoautotrophic productivity, with the highest rates from Movile Cave at 281 g …
The Influence Of Fallback Foods On Great Ape Tooth Enamel, Paul J. Constantino, Peter W. Lucas, James J.-W. Lee, Brian R. Lawn
The Influence Of Fallback Foods On Great Ape Tooth Enamel, Paul J. Constantino, Peter W. Lucas, James J.-W. Lee, Brian R. Lawn
Biological Sciences Faculty Research
Lucas and colleagues recently proposed a model based on fracture and deformation concepts to describe how mammalian tooth enamel may be adapted to the mechanical demands of diet (Lucas et al.: Bioessays 30[2008] 374-385). Here we review the applicability of that model by examining existing data on the food mechanical properties and enamel morphology of great apes (Pan, Pongo, and Gorilla). Particular attention is paid to whether the consumption of fallback foods is likely to play a key role in influencing great ape enamel morphology. Our results suggest that this is indeed the case. We also consider the implications of …
Mineralogy And Micromorphology Of An Atacama Desert Soil, Chile: A Model For Hyperarid Pedogenesis, Michael S. Howell
Mineralogy And Micromorphology Of An Atacama Desert Soil, Chile: A Model For Hyperarid Pedogenesis, Michael S. Howell
UNLV Theses, Dissertations, Professional Papers, and Capstones
The Atacama Desert is the oldest and driest desert on Earth. Hyperarid soils in this desert are dominated by rare (or exclusive) salt minerals and assemblages. Previous research details salt origins and abundance, however pedogenic processes involved in salt distribution are not adequately explained. Therefore, the main goal of this investigation was to identify and document evidence for hyperarid pedogenesis (via salt mineralogy and soil micromorphology) at a field site, Oficina Ercilla, located ~80 km northeast of Antofagasta, Chile within the Central Depression and hyperarid core of the Atacama Desert. This study presents an interpretational model for hyperarid pedogenesis, which …
Analytical Method Development For Determination Of Volatile Organic Compounds In Calcareous Desert Soil, Mary F. Turner
Analytical Method Development For Determination Of Volatile Organic Compounds In Calcareous Desert Soil, Mary F. Turner
UNLV Theses, Dissertations, Professional Papers, and Capstones
Soil sample preservation for volatile organic compound analysis generally requires short sample holding times or preservation of the sample's chemical constituents with sodium bisulfate (NaHSO 4 ). Calcareous soils cannot be preserved using NaHSO4 because effervescence will promote the loss of analytes, and short holding times before analysis are not practical for remote sampling locations. An experimental approach was developed for determination of volatile organic compounds (VOCs) in soil that utilizes solid sorbents for sample preservation and solid-phase microextraction (SPME) sample preparation technique coupled with gas chromatography/mass spectrometry (GC/MS) for analysis. Solid sorbents are used to sequester readily extractable (vapor …
Export Of Terrestrial Dissolved Organic Matter Along A River To Ocean Transect Of The Lower Chesapeake Bay Investigated By Advanced Analytical Techniques, Rachel Leigh Sleighter
Export Of Terrestrial Dissolved Organic Matter Along A River To Ocean Transect Of The Lower Chesapeake Bay Investigated By Advanced Analytical Techniques, Rachel Leigh Sleighter
Chemistry & Biochemistry Theses & Dissertations
Ultrahigh resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) has proved essential for the complete separation of the thousands of peaks present in natural organic matter (NOM), a complex assemblage of organic molecules present in water, soils, and sediments. An improved understanding of its composition is crucial to understand how pollutants interact with NOM and how NOM cycles through global carbon cycles.
Optimizing the acquisition and handling of the FTICR mass spectra is the first step to obtaining high quality data. A simple method to internally calibrate the peaks in the complex spectra, using naturally present fatty …
Biogenic Tracers Through The Holocene On The Alaskan Shelf, Carie A. Curry
Biogenic Tracers Through The Holocene On The Alaskan Shelf, Carie A. Curry
OES Theses and Dissertations
Dramatic environmental changes in the Arctic Ocean have been observed for the last two decades including changing the amount of sea ice thickness and extent, and increased river discharge. In order to put these and other current day observations into historical context and perhaps reveal mechanisms controlling them, a suite of paleo-proxies were used to analyze two high resolution cores collected on the 2005 HOTRAX expedition. The goals of this research were: (1) develop an analytical method for determining biogenic calcite, (2) identify the major sources of biogenic matter into the system over the Holocene, and (3) assemble the history …
Impacts Of Alterations Of Organic Inputs On The Bacterial Community Within The Sediments Of Wind Cave, South Dakota, Usa, Marisa K. Chelius, Guy Beresford, Howard Horton, Meghan Quirk, Greg Selby, Rodney T. Simpson, Rodney Horrocks, John C. Moore
Impacts Of Alterations Of Organic Inputs On The Bacterial Community Within The Sediments Of Wind Cave, South Dakota, Usa, Marisa K. Chelius, Guy Beresford, Howard Horton, Meghan Quirk, Greg Selby, Rodney T. Simpson, Rodney Horrocks, John C. Moore
International Journal of Speleology
Wind Cave (WICA) in the Black Hills of South Dakota, like many mostly dry caves in temperate regions is an energy-starved system. The biotic communities that reside in these systems are low in diversity and simple in structure, and sensitive to changes in external inputs of organic matter. Caves open to tourist traffic offer an opportunity to study the impacts of organic matter amendments in the form of human and rodent hair and dander, clothing lint, material from rodent activity (nesting materials and feces), and algal growth in and around artificial lighting. This study reports on the impacts of carbon …
Ultraviolet Radiation Sensitivity In Cave Bacteria: Evidence Of Adaptation To The Subsurface?, Jessica R. Snider, Caitlin Goin, Robert V. Miller, Penelope J. Boston, Diana E. Northup
Ultraviolet Radiation Sensitivity In Cave Bacteria: Evidence Of Adaptation To The Subsurface?, Jessica R. Snider, Caitlin Goin, Robert V. Miller, Penelope J. Boston, Diana E. Northup
International Journal of Speleology
We hypothesize that a reduced capacity to withstand or repair cellular damage from ultraviolet radiation may be present in cave-adapted microorganisms that never experience such conditions. However, a small number of previous studies have shown that some subsurface bacteria do not show greater sensitivity to ultraviolet radiation (UVR) than surface bacteria. To estimate UVR sensitivity in cave bacteria, bacterial isolates were collected from Carlsbad Cavern, New Mexico, U.S.A., and percent survival following exposure to various UVC and UVA radiation doses was determined. Cave bacteria from Left Hand Tunnel in Carlsbad Cavern and surface bacteria from soil and rocks above Carlsbad …
Pidoplitchkoviella Terricola – An Interesting Fungus From The Domica Cave (Slovakia), Alena Nováková
Pidoplitchkoviella Terricola – An Interesting Fungus From The Domica Cave (Slovakia), Alena Nováková
International Journal of Speleology
The microfungus Pidoplitchkoviella terricola – until now it was known only as Kirilenko´s specimen isolated from Quercus robur rhizosphere in Ukraine - was found in earthworm casts in the Domica Cave, NP Slovak Karst, Slovakia. A description and microphotographs of this strain are provided in this article.
Exploring The Secrets Of The Three-Dimensional Architecture Of Phototrophic Biofilms In Caves, Mònica Roldán, Mariona Hernández-Mariné
Exploring The Secrets Of The Three-Dimensional Architecture Of Phototrophic Biofilms In Caves, Mònica Roldán, Mariona Hernández-Mariné
International Journal of Speleology
Caves with dim natural light, and lighted hypogean environments, have been found to host phototrophic microorganisms from various taxonomic groups. These microorganisms group themselves into assemblies known as communities or biofilms, which are associated with rock surfaces. In this work, the phototrophic biofilms that colonise speleothems, walls and floors in three tourist caves (Spain) were studied. Confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) were used to study these organisms and acquire three-dimensional data on their biofilm structure. CLSM was used in a multi-channel mode whereby the different channels map individual biofilm components. Cyanobacteria, green microalgae, diatoms, mosses …
Lights And Shadows On The Conservation Of A Rock Art Cave: The Case Of Lascaux Cave, Fabiola Bastian, Claude Alabouvette
Lights And Shadows On The Conservation Of A Rock Art Cave: The Case Of Lascaux Cave, Fabiola Bastian, Claude Alabouvette
International Journal of Speleology
Lascaux Cave was discovered in 1940. Twenty years after the first microbial contamination signs appeared. In the last forty years the cave suffered different fungal invasions. Here we discuss the past, present and future of the cave and the conservation of its rock art paintings to the light of data obtained using culture-dependent and –independent methods.
Microscopic Fungi Isolated From The Domica Cave System (Slovak Karst National Park, Slovakia). A Review, Alena Nováková
Microscopic Fungi Isolated From The Domica Cave System (Slovak Karst National Park, Slovakia). A Review, Alena Nováková
International Journal of Speleology
A broad spectrum, total of 195 microfungal taxa, were isolated from various cave substrates (cave air, cave sediments, bat droppings and/or guano, earthworm casts, isopods and diplopods faeces, mammalian dung, cadavers, vermiculations, insect bodies, plant material, etc.) from the cave system of the Domica Cave (Slovak Karst National Park, Slovakia) using dilution, direct and gravity settling culture plate methods and several isolation media. Penicillium glandicola, Trichoderma polysporum, Oidiodendron cerealis, Mucor spp., Talaromyces flavus and species of the genus Doratomyces were isolated frequently during our study. Estimated microfungal species diversity was compared with literature records from the same …
Microbial Communities And Associated Mineral Fabrics In Altamira Cave, Spain, Soledad Cuezva, Sergio Sanchez-Moral, Cesareo Saiz-Jimenez, Juan Carlos Cañaveras
Microbial Communities And Associated Mineral Fabrics In Altamira Cave, Spain, Soledad Cuezva, Sergio Sanchez-Moral, Cesareo Saiz-Jimenez, Juan Carlos Cañaveras
International Journal of Speleology
Evidences of microbial colonizations were observed in Altamira Cave, Spain. These consisted of distinct small coloured colonies, both on walls and ceiling, mainly located in the area near the cave entrance, which progressed until reaching the Polychromes Hall. The colonizations were characterized by a high morphological and microstructural variability and related to biomineralization processes. Two main types of CaCO3 deposits were related to the colonies: rosette- or nest-like aggregates of rhombohedral calcite crystals, and spheroid to hemispheroid CaCO3 elements. Colonies distribution seems to be controlled by microenvironmental conditions inside the cavity. The areas of the cave showing higher …
Guanophilic Fungi In Three Caves Of Southwestern Puerto Rico, Ángel M. Nieves-Rivera, Carlos J. Santos-Flores, Frank M. Dugan, Thomas E. Miller
Guanophilic Fungi In Three Caves Of Southwestern Puerto Rico, Ángel M. Nieves-Rivera, Carlos J. Santos-Flores, Frank M. Dugan, Thomas E. Miller
International Journal of Speleology
Fifty species of guanophilic (bat guano-loving) fungi were isolated from field-collected samples within three caves in southwestern Puerto Rico; most were mitosporic fungi (23 species). The caves studied were Cueva La Tuna (Cabo Rojo), Cueva de Malano (Sistema de Los Chorros, San Germán), and Cueva Viento (El Convento Cave-Spring System, Guayanilla-Peñuelas). The most conspicuous fungus by far was the zygomycete Circinella umbellata (Mucorales). Circinella umbellata dominated the bat guano incubation chambers (Petri dishes lined with sterile filter paper moistened with sterile water) at ambient laboratory conditions. Nineteen species of basidiomycetes (e.g., Ganoderma cf. resinaceum, Geastrum cf. minimum, Lepiota …
Cottonballs, A Unique Subaqeous Moonmilk, And Abundant Subaerial Moonmilk In Cataract Cave, Tongass National Forest, Alaska, Megan D. Curry, Penelope J. Boston, Mike N. Spilde, James F. Baichtal, Andrew R. Campbell
Cottonballs, A Unique Subaqeous Moonmilk, And Abundant Subaerial Moonmilk In Cataract Cave, Tongass National Forest, Alaska, Megan D. Curry, Penelope J. Boston, Mike N. Spilde, James F. Baichtal, Andrew R. Campbell
International Journal of Speleology
The Tongass National Forest is known for its world-class karst features and contains the largest concentration of dissolutional caves in Alaska. Within these karst systems exist unusual and possibly unique formations exhibiting possible biological origin or influence. Cataract Cave is an example of such a system. This cave hosts a unique depositional setting in which so-called “cottonballs” line two permanent pools. The cottonballs are a calcitic deposit heavily entwined within a mass of microbial filaments. They are juxtaposed with extensive subaerial calcitic moonmilk wall deposit of a more conventional nature but of an extraordinary thickness and abundance. Both the cottonballs …
Observations On The Cave-Associated Beetles (Coleoptera) Of Nova Scotia, Canada, Max Moseley
Observations On The Cave-Associated Beetles (Coleoptera) Of Nova Scotia, Canada, Max Moseley
International Journal of Speleology
The cave-associated invertebrates of Nova Scotia constitute a fauna at a very early stage of post-glacial recolonization. The Coleoptera are characterized by low species diversity. A staphylinid Quedius spelaeus spelaeus, a predator, is the only regularly encountered beetle. Ten other terrestrial species registered from cave environments in the province are collected infrequently. They include three other rove-beetles: Brathinus nitidus, Gennadota canadensis and Atheta annexa. The latter two together with Catops gratiosus (Leiodidae) constitute a small group of cave-associated beetles found in decompositional situations. Quedius s. spelaeus and a small suite of other guanophiles live in accumulations of …
Seeing Shifts: Ecologists' Lived Experiences Of Climate Change In Mountains Of The American West, Kimberly Ford Langmaid
Seeing Shifts: Ecologists' Lived Experiences Of Climate Change In Mountains Of The American West, Kimberly Ford Langmaid
Antioch University Dissertations & Theses
This study explores the lived experiences of field ecologists who research the effects of global climate change on mountain species and ecosystems in the American West. The purpose is to generate narrative descriptions of ecologists’ experiences in order to communicate about both the scientific ecology and human ecology of climate change. Twenty prominent field ecologists participated in this study. Interviews with ecologists were transcribed and analyzed using a hermeneutic phenomenological methodology. Eight experiential themes emerged through the process of data analysis, and these themes provide the structure for presenting narratives of ecologists’ experiences. The eight themes are: thinking ecologically, the …
Melting Of Major Glaciers In The Western Himalayas: Evidence Of Climatic Changes From Long Term Msu Derived Tropospheric Temperature Trend (1979-2008), Anup K. Prasad, Keun-Hang Susan Yang, Hesham El-Askary, Menas Kafatos
Melting Of Major Glaciers In The Western Himalayas: Evidence Of Climatic Changes From Long Term Msu Derived Tropospheric Temperature Trend (1979-2008), Anup K. Prasad, Keun-Hang Susan Yang, Hesham El-Askary, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
Global warming or the increase of the surface and atmospheric temperatures of the Earth, is increasingly discernible in the polar, sub-polar and major land glacial areas. The Himalayan and Tibetan Plateau Glaciers, which are the largest glaciers outside of the Polar regions, are showing a large-scale decrease of snow cover and an extensive glacial retreat. These glaciers such as Siachen and Gangotri are a major water resource for Asia as they feed major rivers such as the Indus, Ganga and Brahmaputra. Due to scarcity of ground measuring stations, the long-term observations of atmospheric temperatures acquired from the Microwave Sounding Unit …
Sequence And Chemostratigraphic Study Across The Basal Eureka Quartzite Unconformity In The Great Basin, Nevada: Implications For The Origin Of The Late Ordovician Carbon Isotope Excursion, Apostolos Paul Kosmidis
Sequence And Chemostratigraphic Study Across The Basal Eureka Quartzite Unconformity In The Great Basin, Nevada: Implications For The Origin Of The Late Ordovician Carbon Isotope Excursion, Apostolos Paul Kosmidis
UNLV Theses, Dissertations, Professional Papers, and Capstones
The positive carbon isotope (δ 13 C) excursion from the late Middle Ordovician Copenhagen Formation that underlies the Eureka Quartzite in central Nevada has been hypothesized to record a global cooling event ∼10 Myr prior to the well-recognized Late Ordovician Hirnantian glaciation (∼443 Ma). However, direct evidence for pre-Hirnantian continental glaciation remains scarce, raising uncertainties in the relationship between the inferred eustatic sea-level fall and the origin of the positive δ 13 C excursion. Additionally, previous stratigraphic studies from southern Nevada and California suggest relative sea-level fall in excess of ∼ 150 meters, which exceeds estimates for younger glacial periods …
Bending Of Woody Riparian Vegetation As A Function Of Hydraulic Flow Conditions, John O. Goreham
Bending Of Woody Riparian Vegetation As A Function Of Hydraulic Flow Conditions, John O. Goreham
UNLV Theses, Dissertations, Professional Papers, and Capstones
Vegetation encroachment reduces channel conveyance capacity below design objectives and greatly increases the risk for loss of life and property damage in the case of large flood events. Given minimal knowledge of hydraulic roughness for shrubs and woody vegetation, accurate estimation of channel capacity and water surface elevation is difficult. The ability to predict a tree's bent, reduced height in the presence of flow permits more accurate prediction of hydraulic roughness and water surface elevation.
In this study, field tests were performed to elucidate tree bending properties, which in turn served as input parameters for a numerical algorithm designed to …
Soil Moisture And Water Stage Estimation Using Precipitation Radar, Sumit Puri
Soil Moisture And Water Stage Estimation Using Precipitation Radar, Sumit Puri
UNLV Theses, Dissertations, Professional Papers, and Capstones
In south-western United States, soil moisture data is important for drought studies in the region which is experiencing a drought for many years, whereas in South Florida, water stage data is required by hydrologists to monitor the hydrological flow in wetlands. Soil moisture data and water stage data are not sufficiently available due to sparse monitoring stations. Installation of dense measuring stations over an extended area is costly and labor intensive. Therefore, there is a need to develop an alternative method of measuring soil moisture and water stage. Microwave remote sensing has proven to be a useful tool in the …
Desert Varnish As An Indicator Of Modern-Day Air Pollution In Southern Nevada, Piotr Nowinski
Desert Varnish As An Indicator Of Modern-Day Air Pollution In Southern Nevada, Piotr Nowinski
UNLV Theses, Dissertations, Professional Papers, and Capstones
Rock varnish, often called desert varnish, is a slow-growing, manganese-rich coating that accumulates on exposed rock surfaces. The mechanism of varnish formation is not fully understood, however, most authors agree that varnishes derive their components from the atmosphere. The main goal of this study was to demonstrate the potential use of desert varnish as a passive environmental monitor of present and past atmospheric pollution. Analysis of varnishes is a new field that can potentially provide records of pre-anthropogenic levels of atmospheric metals and other environmental pollutants. To evaluate the potential of desert varnish as an environmental monitoring tool, the following …
Global Distribution Of Atmospheric Phosphorus Sources, Concentrations And Deposition Rates, And Anthropogenic Impacts, Natalie Mahowald, Timothy D. Jickells, Alex R. Baker, Paulo Artaxo, Claudia R. Benitez-Nelson, Gilles Bergametti, Tami C. Bond, Ying Chen, David D. Cohen, Barak Herut, Nilgun Kubilay, Remi Losno, Chao Luo, Willy Maenhaut, Kenneth A. Mcgee, Gregory S. Okin, Ronald L. Siefert, Seigen Tsukuda
Global Distribution Of Atmospheric Phosphorus Sources, Concentrations And Deposition Rates, And Anthropogenic Impacts, Natalie Mahowald, Timothy D. Jickells, Alex R. Baker, Paulo Artaxo, Claudia R. Benitez-Nelson, Gilles Bergametti, Tami C. Bond, Ying Chen, David D. Cohen, Barak Herut, Nilgun Kubilay, Remi Losno, Chao Luo, Willy Maenhaut, Kenneth A. Mcgee, Gregory S. Okin, Ronald L. Siefert, Seigen Tsukuda
Faculty Publications
[1] A worldwide compilation of atmospheric total phosphorus (TP) and phosphate (PO4) concentration and deposition flux observations are combined with transport model simulations to derive the global distribution of concentrations and deposition fluxes of TP and PO4. Our results suggest that mineral aerosols are the dominant source of TP on a global scale (82%), with primary biogenic particles (12%) and combustion sources (5%) important in nondusty regions. Globally averaged anthropogenic inputs are estimated to be ∼5 and 15% for TP and PO4, respectively, and may contribute as much as 50% to the deposition over the oligotrophic ocean where productivity may …
Slides: Idaho Rental Pool: Rules And Procedures, Idaho Water Resource Board, Jerry R. Rigby
Slides: Idaho Rental Pool: Rules And Procedures, Idaho Water Resource Board, Jerry R. Rigby
Evolving Regional Frameworks for Ag-to-Urban Water Transfers (December 11)
Presenter: Jerry Rigby, Counsel for Fremont‐Madison Irrigation District, Rigby, Thatcher, Andrus, Rigby & Moeller, Idaho
25 slides