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Articles 541 - 570 of 1349

Full-Text Articles in Geology

Nutrient Variations Of Six Surface Water Bodies In Mchenry County, Il, Jacob Piske May 2017

Nutrient Variations Of Six Surface Water Bodies In Mchenry County, Il, Jacob Piske

Celebration of Learning

This research analyzes water quality from several ponds in McHenry County, Illinois, with a goal of developing a understanding of pollution sources and temporal variations in concentrations of nitrate, potassium, phosphorus, chlorine, and sodium. Over the past 25 years, the population of McHenry County has grown rapidly, with residential developments expanding into former farmlands. Yet, the county remains heavily agricultural, with roughly 60% of the surface area used for agricultural purposes. Concentrations of NO3-, P+, K+, Cl-, and Na+ were analyzed from six sites: two in subdivisions, two in farmland, and two near major highways. Data were collected once a …


Impacts On The Stakeholders Of The Nexus Pipeline, Jessica A. Speweike May 2017

Impacts On The Stakeholders Of The Nexus Pipeline, Jessica A. Speweike

Honors Projects

This journalistic feature covers the different impacts on those individuals who are involved with or affected by the Nexus Gas Transmission pipeline. Testimony from Ohio landowners, activists, scientists and public officials cover a variety of opinions and concerns raised by the pipeline. Private property rights, environmental impact, and possible economic implications are detailed by those who have been involved with the Nexus pipeline since its early stages of implementation.


Sensitivity Of Mangrove Range Limits To Climate Variability, Kyle C. Cavanaugh, Michael J. Osland, Remi Bardou, Gustavo Hinojosa-Arango, Juan M. Lopez-Vivas, John D. Parker, Andre S. Rovai Apr 2017

Sensitivity Of Mangrove Range Limits To Climate Variability, Kyle C. Cavanaugh, Michael J. Osland, Remi Bardou, Gustavo Hinojosa-Arango, Juan M. Lopez-Vivas, John D. Parker, Andre S. Rovai

United States Geological Survey: Staff Publications

Aim: Correlative distribution models have been used to identify potential climatic controls of mangrove range limits, but there is still uncertainty about the relative importance of these factors across different regions. To provide insights into the strength of climatic control of different mangrove range limits, we tested whether temporal variability in mangrove abundance increases near range limits and whether this variability is correlated with climatic factors thought to control large scale mangrove distributions.

Location: North and South America.

Time period: 1984–2011.

Major taxa studied: Avicennia germinans, Avicennia schuaeriana, Rhizophora mangle, Laguncularia racemosa.

Methods: We characterized temporal variability in the enhanced …


Creating A Scaling Relationship Between Peak Discharge And Drainage Area To Identify Tile Drainage Inputs Into An Agricultural Stream, Ryan Plath Apr 2017

Creating A Scaling Relationship Between Peak Discharge And Drainage Area To Identify Tile Drainage Inputs Into An Agricultural Stream, Ryan Plath

Theses and Dissertations

Tile drains have been shown to contribute to high levels of nitrate in agricultural streams. Locations of tile drains on a watershed scale, however, are often unknown due to tile drains being located on many separate parcels of private property. This study evaluates the ability of a methodology, using scaling relationships between discharge and drainage area, for locating areas of large tile drainage contribution to Money Creek, in McLean County, Illinois. Additionally, this study examines the difference in scaling relationships and physical stream hydrology between tileflow and no-tileflow conditions. Eight stream sites were created in the watershed, that recorded stage …


Investigations Of The Spatial And Temporal Variations Of Sr And Nd Isotopes In Sediments From Two Indian Rivers: Implications To Source Identification, Sonali Pradhan, Jing Zhang, Mark Baskaran, Prabhaker Vasant Shirodkar, Ying Wu, Umesh Kumar Pradhan Apr 2017

Investigations Of The Spatial And Temporal Variations Of Sr And Nd Isotopes In Sediments From Two Indian Rivers: Implications To Source Identification, Sonali Pradhan, Jing Zhang, Mark Baskaran, Prabhaker Vasant Shirodkar, Ying Wu, Umesh Kumar Pradhan

Environmental Science and Geology Faculty Research Publications

Radiogenic isotopes of Sr and Nd provide crucial information on chemical and physical erosion processes, therefore used as tracers for fingerprinting the sources of fluvial sediments. Moreover, elemental geochemistry, 87Sr/86Sr and 143Nd/144Nd signatures in silicate fractions of sediments primarily reflect intricate controls of characteristics and provenance of sediment. A suite of sediment samples collected from two rivers of India, Narmada (large) and Netravati (small) were analyzed for elemental concentrations, 87Sr/86Sr and 143Nd/144Nd in silicate as well as acid-leachable fractions. 87Sr/86Sr in acid-leachable sediment fractions from both the rivers (0.7094 ± 0.0002 for Narmada and 0.7158 ± 0.003 for Netravati) showed …


Δ13c And Δ15n In The Endangered Kemp’S Ridley Sea Turtle Lepidochelys Kempii After The Deepwater Horizon Oil Spill, Kimberly J. Reich, Melania C. López-Castro, Donna J. Shaver, Claire Iseton, Kristen M. Hart, Michael J. Hooper, Christopher J. Schmitt Apr 2017

Δ13c And Δ15n In The Endangered Kemp’S Ridley Sea Turtle Lepidochelys Kempii After The Deepwater Horizon Oil Spill, Kimberly J. Reich, Melania C. López-Castro, Donna J. Shaver, Claire Iseton, Kristen M. Hart, Michael J. Hooper, Christopher J. Schmitt

United States Geological Survey: Staff Publications

The Deepwater Horizon explosion in April 2010 and subsequent oil spill released 3.19 × 106 barrels (5.07 × 108 l) of MC252 crude oil into important foraging areas of the endangered Kemp’s ridley sea turtle Lepidochelys kempii (Lk) in the northern Gulf of Mexico (GoM). We measured δ13C and δ15N in scute biopsy samples from 33 Lk nesting in Texas during the period 2010 to 2012. Of these, 27 were equipped with satellite transmitters and were tracked to traditional foraging areas in the northern GoM after the spill. Differences in δ13C between the oldest and newest scute layers from 2010 …


Vegetation Response To Invasive Tamarix Control In Southwestern U.S. Rivers: A Collaborative Study Including 416 Sites, Eduardo Gonzalez, Anna A. Sher, Robert M. Anderson, Robin F. Bay, Daniel W. Bean, Gabriel J. Bissonnete, Berenger Bourgeois, David J. Cooper, Kara Dohrenwend, Kim D. Eichhorst, Hishma El Waer, Deborah K. Kennard, Rebecca Harms-Weissinger, Annie L. Henry, Lori J. Makarick, Steven M. Ostoja, Lindsay V. Reynolds, W. Wright Robinson, Patrick B. Shafroth Apr 2017

Vegetation Response To Invasive Tamarix Control In Southwestern U.S. Rivers: A Collaborative Study Including 416 Sites, Eduardo Gonzalez, Anna A. Sher, Robert M. Anderson, Robin F. Bay, Daniel W. Bean, Gabriel J. Bissonnete, Berenger Bourgeois, David J. Cooper, Kara Dohrenwend, Kim D. Eichhorst, Hishma El Waer, Deborah K. Kennard, Rebecca Harms-Weissinger, Annie L. Henry, Lori J. Makarick, Steven M. Ostoja, Lindsay V. Reynolds, W. Wright Robinson, Patrick B. Shafroth

United States Geological Survey: Staff Publications

Most studies assessing vegetation response following control of invasive Tamarix trees along southwestern U.S. rivers have been small in scale (e.g., river reach), or at a regional scale but with poor spatial-temporal replication, and most have not included testing the effects of a now widely used biological control. We monitored plant composition following Tamarix control along hydrologic, soil, and climatic gradients in 244 treated and 172 reference sites across six U.S. states. This represents the largest comprehensive assessment to date on the vegetation response to the four most common Tamarix control treatments. Biocontrol by a defoliating beetle (treatment 1) reduced …


Impact Of Icebergs On Net Primary Productivity In The Southern Ocean, Shuang-Ye Wu, Shugui Hou Mar 2017

Impact Of Icebergs On Net Primary Productivity In The Southern Ocean, Shuang-Ye Wu, Shugui Hou

Department of Earth, Environment and Sustainability Faculty Publications

Productivity in the Southern Ocean (SO) is iron-limited, and supply of iron dissolved from aeolian dust is believed to be the main source from outside the marine environment. However, recent studies show that icebergs could provide a comparable amount of bioavailable iron to the SO as aeolian dust. In addition, small-scale areal studies suggest increased concentrations of chlorophyll, krill, and seabirds surrounding icebergs. Based on previous research, this study aims to examine whether iceberg occurrence has a significant impact on marine productivity at the scale of the SO, using remote sensing data of iceberg occurrences and ocean net primary productivity …


Dynamics Of Nitrate, Phosphorus, And Suspended Sediment Transport In Two Agricultural Streams In Central Illinois, Luke W. Lampo Mar 2017

Dynamics Of Nitrate, Phosphorus, And Suspended Sediment Transport In Two Agricultural Streams In Central Illinois, Luke W. Lampo

Theses and Dissertations

Nutrients such as nitrate and phosphorus are necessary for life, but excessive amounts can be detrimental. Large amounts of nutrients entering bodies of water can lead to hypoxic zones such as the one in the Gulf of Mexico. Nutrients are also problematic in drinking water reservoirs, as high concentrations of nitrate in drinking water can cause health conditions such as blue baby syndrome and high phosphorus concentrations can lead to algal blooms. Suspended sediment leads to reservoir sedimentation, habitat degradation, and is able to transport particulate nutrients. High nutrient and sediment concentrations are a recurring problem in the drinking water …


Velocity Variations And Uncertainty From Transdimensional P-Wave Tomography Of North America, Scott Burdick, Vedran Lekić Mar 2017

Velocity Variations And Uncertainty From Transdimensional P-Wave Tomography Of North America, Scott Burdick, Vedran Lekić

Environmental Science and Geology Faculty Research Publications

High-resolution models of seismic velocity variations constructed using body-wave tomography inform the study of the origin, fate and thermochemical state of mantle domains. In order to reliably relate these variations to material properties including temperature, composition and volatile content, we must accurately retrieve both the patterns and amplitudes of variations and quantify the uncertainty associated with the estimates of each. For these reasons, we image the mantle beneath North America with P-wave traveltimes from USArray using a novel method for 3-D probabilistic body-wave tomography. The method uses a Transdimensional Hierarchical Bayesian framework with a reversible-jump Markov Chain Monte Carlo algorithm …


Investigation Of Firn Aquifer Structure In Southeastern Greenland Using Active Source Seismology, Lynn N. Montgomery, Nicholas Schmerr, Scott Burdick, Richard R. Forster, Lora Koenig, Anatoly Legchenko, Stefan Ligtenberg, Clément Miège, Olivia L. Miller, D. Kip Solomon Feb 2017

Investigation Of Firn Aquifer Structure In Southeastern Greenland Using Active Source Seismology, Lynn N. Montgomery, Nicholas Schmerr, Scott Burdick, Richard R. Forster, Lora Koenig, Anatoly Legchenko, Stefan Ligtenberg, Clément Miège, Olivia L. Miller, D. Kip Solomon

Environmental Science and Geology Faculty Research Publications

In spring of 2011, a perennial storage of water was observed in the firn of the southeastern Greenland Ice Sheet (GrIS), a region of both high snow accumulation and high melt. This aquifer is created through percolation of surface meltwater downward through the firn, saturating the pore space above the ice-firn transition. The aquifer may play a significant role in sea level rise through storage or draining freshwater into the ocean. We carried out a series of active source seismic experiments using continuously refracted P-waves and inverted the first P-arrivals using a transdimensional Bayesian approach where the depth, velocity, and …


Murray Energy Corporation V. Mccarthy, Sarah M. Danno Feb 2017

Murray Energy Corporation V. Mccarthy, Sarah M. Danno

Public Land & Resources Law Review

Holding that the widespread effects of environmental regulation on the coal industry constituted sufficient importance, the Northern District of West Virginia ordered the Environmental Protection Agency to conduct analysis on employment loss and plant reduction resulting from regulatory effects. In admonishing the EPA’s inaction, the court ruled that the Agency had a non-discretionary duty to evaluate employment and plant reduction. Furthermore, the court held that the EPA’s attempt to put forth general reports in place of required evaluations was an invalid attempt to circumvent its statutory duty.


The Tuscaloosa Marine Shale: Geologic History, Depositional Analysis, And Exploration Potential, Jessica D. Pair Feb 2017

The Tuscaloosa Marine Shale: Geologic History, Depositional Analysis, And Exploration Potential, Jessica D. Pair

Electronic Theses and Dissertations

The Tuscaloosa Marine Shale (TMS) was deposited across southern Louisiana and Mississippi during the Upper Cretaceous. The study focuses on a core region containing vast deposits of Cretaceous-aged sediments that have economic importance for oil and gas exploration. This region has been conventionally drilled for decades, focusing on the recovery of the Cretaceous hydrocarbons. Explorers within this region had traditionally targeted the massive sand units of the Lower and Upper Tuscaloosa Group while neglecting the middle Tuscaloosa Marine Shale unit. With the onset of unconventional drilling technology, new explorers to the region have begun to delineate the Tuscaloosa Marine Shale’s …


Memorium: Bhamidipati Lakshmidhara Kanakadri Somayajulu (1937-2016), Mark Baskaran, R. Ramesh Jan 2017

Memorium: Bhamidipati Lakshmidhara Kanakadri Somayajulu (1937-2016), Mark Baskaran, R. Ramesh

Environmental Science and Geology Faculty Research Publications

The demise of B. L. K. Somayajulu, an illustrious nuclear geochemist, brings great sadness to the community of geo- logists, geochemists and oceanographers in India and elsewhere.


Diet Composition Of Age-0 Fishes In Created Habitats Of The Lower Missouri River, Trevor A. Starks, James M. Long Jan 2017

Diet Composition Of Age-0 Fishes In Created Habitats Of The Lower Missouri River, Trevor A. Starks, James M. Long

United States Geological Survey: Staff Publications

Channelization of the Missouri River has greatly reduced the availability of shallow water habitats used by many larval and juvenile fishes and contributed to imperilment of floodplain-dependent biota. Creation of small side channels, or chutes, is being used to restore shallow water habitat and reverse negative environmental effects associated with channelization. In the summer of 2012, the U.S. Army Corps of Engineers collected early life stages of fishes from constructed chutes and nearby unrestored shallow habitats at six sites on the Missouri River between Rulo, Nebraska and St. Louis, Missouri. We compared the diets of two abundant species of fishes …


Toxicity Of Fluorescent Tracers And Their Degradation Byproducts, Philippe Gombert, Hugues Biaudet, René De Sèze, Pascal Pandard, Jean Carré Jan 2017

Toxicity Of Fluorescent Tracers And Their Degradation Byproducts, Philippe Gombert, Hugues Biaudet, René De Sèze, Pascal Pandard, Jean Carré

International Journal of Speleology

Tracer tests are frequently used to delineate catchment area of water supply springs in karstic zones. In the karstic chalk of Normandy, the main tracers used are fluorescent: uranine, sulforhodamine B, naphtionate, and Tinopal®. In this area, a statistical analysis shows that less than half of the injected tracers joins the monitored restitution points and enters the drinking water system where they undergo chlorination. Most of the injected tracers is absorbed in the rock matrix or is thrown out of the aquifer via karstic springs: then it can join superficial waters where it is degraded due to the sun and …


Effects Of Habitat Restoration On Soil Retention On Santa Rosa Island, Michael Perez, Kathryn Mceachern, Ken Niessen Jan 2017

Effects Of Habitat Restoration On Soil Retention On Santa Rosa Island, Michael Perez, Kathryn Mceachern, Ken Niessen

STAR Program Research Presentations

Ranching began on Santa Rosa Island in the 1840’s, consequently introducing nonnative megafauna that put novel selective grazing pressures on endemic plant species. Their movement patterns also altered substrate integrity as the land became denuded of any stabilizing vegetation. Dense groves of island oak (Q. tomentella) are known to aid in sediment deposition and retention. The groves also function to collect water during periods of intense fog common to the island. This experiment sought to determine whether sediment is being lost or deposited on a ridge in the middle of the island containing a grove of Q. tomentella …


Greater Sage-Grouse Population Trends Across Wyoming, David R. Edmunds, Cameron L. Aldridge, Michael S. O'Donnell, Adrian P. Monroe Jan 2017

Greater Sage-Grouse Population Trends Across Wyoming, David R. Edmunds, Cameron L. Aldridge, Michael S. O'Donnell, Adrian P. Monroe

United States Geological Survey: Staff Publications

The scale at which analyses are performed can have an effect on model results and often one scale does not accurately describe the ecological phenomena of interest (e.g., population trends) for wide-ranging species: yet, most ecological studies are performed at a single, arbitrary scale. To best determine local and regional trends for greater sage-grouse (Centrocercus urophasianus) in Wyoming, USA, we modeled density-independent and -dependent population growth across multiple spatial scales relevant to management and conservation (Core Areas [habitat encompassing approximately 83% of the sage-grouse population on ~24% of surface area in Wyoming], local Working Groups [7 regional areas for …


Taphonomic Problems In Reconstructing Sea-Level History From The Late Quaternary Marine Terraces Of Barbados, Daniel R. Muhs, Kathleen R. Simmons Jan 2017

Taphonomic Problems In Reconstructing Sea-Level History From The Late Quaternary Marine Terraces Of Barbados, Daniel R. Muhs, Kathleen R. Simmons

United States Geological Survey: Staff Publications

Although uranium series (U-series) ages of growth-position fossil corals are important to Quaternary sea-level history, coral clast reworking from storms can yield ages on a terrace dating to more than one high-sea stand, confounding interpretations of sea-level history. On northern Barbados, U-series ages corals from a thick storm deposit are not always younger with successively higher stratigraphic positions, but all date to the last interglacial period (~127 ka to ~112 ka), Marine Isotope Substage (MIS) 5.5. The storm deposit ages are consistent with the ages of growth-position corals found at the base of the section and at landward localities on …


Balancing Stability And Flexibility In Adaptive Governance: An Analysis Of Tools Available In U.S. Environmental Law, Robin Kundis Craig, Ahjond S. Garmestani, Craig R. Allen, Craig Anthony (Tony) Arnold, Hannah E. Birge, Hannah Birge, Daniel A. Decaro, Alexander K. Fremier, Alexander K. Fremier, Hannah Gosnell, Edella C. Schlager Jan 2017

Balancing Stability And Flexibility In Adaptive Governance: An Analysis Of Tools Available In U.S. Environmental Law, Robin Kundis Craig, Ahjond S. Garmestani, Craig R. Allen, Craig Anthony (Tony) Arnold, Hannah E. Birge, Hannah Birge, Daniel A. Decaro, Alexander K. Fremier, Alexander K. Fremier, Hannah Gosnell, Edella C. Schlager

United States Geological Survey: Staff Publications

Adaptive governance must work “on the ground,” that is, it must operate through structures and procedures that the people it governs perceive to be legitimate and fair, as well as incorporating processes and substantive goals that are effective in allowing social-ecological systems (SESs) to adapt to climate change and other impacts. To address the continuing and accelerating alterations that climate change is bringing to SESs, adaptive governance generally will require more flexibility than prior governance institutions have often allowed. However, to function as good governance, adaptive governance must pay real attention to the problem of how to balance this increased …


Smartphone Technologies And Bayesian Networks To Assess Shorebird Habitat Selection, Sara L. Zeigler, E. Robert Thieler, Benjamin T. Gutierrez, Nathaniel G. Plant, Megan Hines, James D. Fraser, Daniel H. Catlin Jan 2017

Smartphone Technologies And Bayesian Networks To Assess Shorebird Habitat Selection, Sara L. Zeigler, E. Robert Thieler, Benjamin T. Gutierrez, Nathaniel G. Plant, Megan Hines, James D. Fraser, Daniel H. Catlin

United States Geological Survey: Staff Publications

Understanding patterns of habitat selection across a species’ geographic distribution can be critical for adequately managing populations and planning for habitat loss and related threats. However, studies of habitat selection can be time consuming and expensive over broad spatial scales, and a lack of standardized monitoring targets or methods can impede the generalization of site-based studies. Our objective was to collaborate with natural resource managers to define available nesting habitat for piping plovers (Charadrius melodus) throughout their U.S. Atlantic coast distribution from Maine to North Carolina, with a goal of providing science that could inform habitat management in …


Camera System Considerations For Geomorphic Applications Of Sfm Photogrammetry, Adam R. Mosbrucker, Jon J. Major, Kurt R. Spicer, John Pitlick Jan 2017

Camera System Considerations For Geomorphic Applications Of Sfm Photogrammetry, Adam R. Mosbrucker, Jon J. Major, Kurt R. Spicer, John Pitlick

United States Geological Survey: Staff Publications

The availability of high-resolution, multi-temporal, remotely sensed topographic data is revolutionizing geomorphic analysis. Three-dimensional topographic point measurements acquired from structure-from-motion (SfM) photogrammetry have been shown to be highly accurate and cost-effective compared to laser-based alternatives in some environments. Use of consumer-grade digital cameras to generate terrain models and derivatives is becoming prevalent within the geomorphic community despite the details of these instruments being largely overlooked in current SfM literature.

A practical discussion of camera system selection, configuration, and image acquisition is presented. The hypothesis that optimizing source imagery can increase digital terrain model (DTM) accuracy is tested by evaluating accuracies …


Channel-Planform Evolution In Four Rivers Of Olympic National Park, Washington, Usa: The Roles Of Physical Drivers And Trophic Cascades, Amy E. East, Kurt J. Jenkins, Patricia J. Happe, Jennifer A. Bountry, Timothy J. Beechie, Mark C. Mastin, Joel B. Sankey, Timothy J. Randle Jan 2017

Channel-Planform Evolution In Four Rivers Of Olympic National Park, Washington, Usa: The Roles Of Physical Drivers And Trophic Cascades, Amy E. East, Kurt J. Jenkins, Patricia J. Happe, Jennifer A. Bountry, Timothy J. Beechie, Mark C. Mastin, Joel B. Sankey, Timothy J. Randle

United States Geological Survey: Staff Publications

Identifying the relative contributions of physical and ecological processes to channel evolution remains a substantial challenge in fluvial geomorphology. We use a 74-year aerial photographic record of the Hoh, Queets, Quinault, and Elwha Rivers, Olympic National Park, Washington, USA, to investigate whether physical or trophic-cascade-driven ecological factors – excessive elk impacts after wolves were extirpated a century ago – are the dominant drivers of channel planform in these gravel-bed rivers.We find that channel width and braiding show strong relationships with recent flood history. All four rivers widened significantly after having been relatively narrow in the 1970s, consistent with increased flood …


Semi-Arid Grassland Bird Responses To Patch-Burn Grazing And Drought, Susan K. Skagen, David J. Augustine, Justin D. Derner Jan 2017

Semi-Arid Grassland Bird Responses To Patch-Burn Grazing And Drought, Susan K. Skagen, David J. Augustine, Justin D. Derner

United States Geological Survey: Staff Publications

As grassland birds of central North America experience steep population declines with changes in land use, management of remaining tracts becomes increasingly important for population viability. The integrated use of fire and grazing may enhance vegetation heterogeneity and diversity in breeding birds, but the subsequent effects on reproduction are unknown. We examined the influence of patch-burn grazing management in shortgrass steppe in eastern Colorado on habitat use and reproductive success of 3 grassland bird species, horned lark (Eremophila alpestris), lark bunting (Calamospiza melanocorys), and McCown’s longspur (Rhynchophanes mccownii), at several spatial scales during 2011 …


Lack Of Observed Movement Response To Lead Exposure Of California Condors, Sharon A. Poessel, Joseph Brandt, Linda Uyeda, Molly Astell, Todd E. Katzner Jan 2017

Lack Of Observed Movement Response To Lead Exposure Of California Condors, Sharon A. Poessel, Joseph Brandt, Linda Uyeda, Molly Astell, Todd E. Katzner

United States Geological Survey: Staff Publications

Lead poisoning is an important conservation concern for wildlife, and scavenging birds are especially at risk from consumption of carcasses of animals killed with lead ammunition. Because current methods to identify lead exposure require animal capture and blood collection, management would benefit from the development of a less costly and noninvasive behavioral test for illness in wild animals. We attempted to design such a test to identify lead exposure in California condors (Gymnogyps californianus) that we tracked with global positioning system (GPS) telemetry in southern California, USA, 2013–2016. We measured blood-lead concentrations in tracked birds and expected that …


Effects Of Industrial And Investigator Disturbance On Arctic-Nesting Geese, Brandt W. Meixell, Paul L. Flint Jan 2017

Effects Of Industrial And Investigator Disturbance On Arctic-Nesting Geese, Brandt W. Meixell, Paul L. Flint

United States Geological Survey: Staff Publications

Oil and gas development on the Arctic Coastal Plain (ACP) of Alaska, USA may have effects on Arctic-nesting birds. To estimate effects of industrial activity and investigator disturbance on avian productivity, we monitored nests of greater white-fronted geese (Anser albifrons) with digital cameras and periodic nest visits during 2013–2014 at 2 sites on the ACP. A disturbed site was adjacent to human-made infrastructure and industrial clean-up activities initiated at the onset of the study and a control site was >2 km from sources of industrial disturbance. We assessed variation in estimates of incubation constancy, nest survival, and predator …


Simulating The Effects Of Management Practices On Cropland Soilorganic Carbon Changes In The Temperate Prairies Ecoregion Of Theunited States From 1980 To 2012, Zhengpeng Li, Shuguang Liu, Zhengxi Tan, Terry L. Sohl, Yiping Wu Jan 2017

Simulating The Effects Of Management Practices On Cropland Soilorganic Carbon Changes In The Temperate Prairies Ecoregion Of Theunited States From 1980 To 2012, Zhengpeng Li, Shuguang Liu, Zhengxi Tan, Terry L. Sohl, Yiping Wu

United States Geological Survey: Staff Publications

Understanding the effects of management practices on soil organic carbon (SOC) is important for design-ing effective policies to mitigate greenhouse gas emissions in agriculture. In the Midwest United States,management practices in the croplands have been improved to increase crop production and reduce SOCloss since the 1980s. Many studies of SOC dynamics in croplands have been performed to understandthe effects of management, but the results are still not conclusive. This study quantified SOC dynam-ics in the Midwest croplands from 1980 to 2012 with the General Ensemble Biogeochemical ModellingSystem (GEMS) and available management data. Our results showed that the total SOC in …


Weathering And Erosion Of Fractured Bedrock Systems, Marina I. Lebedeva, Susan L. Brantley Jan 2017

Weathering And Erosion Of Fractured Bedrock Systems, Marina I. Lebedeva, Susan L. Brantley

United States Geological Survey: Staff Publications

We explore the contribution of fractures (joints) in controlling the rate of weathering advance for a low-porosity rock by using methods of homogenization to create averaged weathering equations. The rate of advance of the weathering front can be expressed as the same rate observed in non-fractured media (or in an individual block) divided by the volume fraction of nonfractured blocks in the fractured parent material. In the model, the parent has fractures that are filled with a more porous material that contains only inert or completely weathered material. The low-porosity rock weathers by reaction-transport processes. As observed in field systems, …


Field Investigation Of An Active Landslide In Kentucky: A Framework To Correlate Electrical Data And Shear Strength, Matthew M. Crawford, L. Sebastian Bryson Jan 2017

Field Investigation Of An Active Landslide In Kentucky: A Framework To Correlate Electrical Data And Shear Strength, Matthew M. Crawford, L. Sebastian Bryson

Report of Investigations--KGS

Landslide hazard assessments are best accomplished by a multidisciplinary approach that connects geologic processes with geotechnical behavior. Tools to accomplish this in the field include geologic characterization, hydrologic monitoring, and geophysical surveys, and in the laboratory, soil-strength testing. Volumetric water content, soil-water potential (suction), local rainfall, and in situ electrical conductivity were measured at a shallow colluvial landslide in Kentucky. Surface electrical-resistivity surveys were also conducted to support interpretations of depth to failure, lithologic differences, and changes in moisture content over time. Correlations of hydrologic data with electrical measurements and shear strength indicate that observed changes in the degree of …


America's National Parks And The Anthropocene: Addressing The Present To Accommodate The Future In Acadia National Park, Sophie A. Swetz Jan 2017

America's National Parks And The Anthropocene: Addressing The Present To Accommodate The Future In Acadia National Park, Sophie A. Swetz

Honors Theses

In 2000, atmospheric chemist, Paul J. Crutzen, and limnologist, Eugene Stoermer, formally proposed the idea of “the Anthropocene,” a new geologic epoch in which humans are the dominant force shaping the Earth. To claim the Anthropocene's existence is to declare that human actions have altered the Earth in such a way that geologic indicators render it a distinct epoch in the stratification of geologic time. This new epoch emerges as a consequence of increased technological development employed to accommodate an anthropocentric human existence. That is, rapid advancements in technology have driven the transformation from a primarily naturally controlled planet to …