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Articles 331 - 360 of 861

Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology

The Aerosphere As A Network Connector Of Organisms And Their Diseases, Jeremy D. Ross, Eli S. Bridge, Diann J. Prosser, John Y. Takekawa Jan 2017

The Aerosphere As A Network Connector Of Organisms And Their Diseases, Jeremy D. Ross, Eli S. Bridge, Diann J. Prosser, John Y. Takekawa

United States Geological Survey: Staff Publications

Aeroecological processes, especially powered flight of animals, can rapidly connect biological communities across the globe. This can have profound consequences for evolutionary diversification, energy and nutrient transfers, and the spread of infectious diseases. The latter is of particular consequence for human populations, since migratory birds are known to host diseases which have a history of transmission into domestic poultry or even jumping to human hosts. In this chapter, we present a scenario under which a highly pathogenic avian influenza (HPAI) strain enters North America from East Asia via postmolting waterfowl migration. We use an agent-based model (ABM) to simulate the …


Exploring The Reasons For The Seasons Using Google Earth, 3d Models, And Plots, Declan G. De Paor, Mladen M. Dordevic, Paul Karabinos, Stephen Burgin, Filis Coba, Steven J. Whitmeyer Jan 2017

Exploring The Reasons For The Seasons Using Google Earth, 3d Models, And Plots, Declan G. De Paor, Mladen M. Dordevic, Paul Karabinos, Stephen Burgin, Filis Coba, Steven J. Whitmeyer

Physics Faculty Publications

Public understanding of climate and climate change is of broad societal importance. However, misconceptions regarding reasons for the seasons abound amongst students, teachers, and the public, many of whom believe that seasonality is caused by large variations in Earth's distance from the Sun. Misconceptions may be reinforced by textbook illustrations that exaggerate eccentricity or show an inclined view of Earth's near-circular orbit. Textbook explanations that omit multiple factors influencing seasons, that do not mesh with students' experiences, or that are erroneous, hinder scientifically valid reasoning. Studies show that many teachers share their students' misconceptions, and even when they understand basic …


Review Of A Chorus Of Cranes: The Cranes Of North America And The World By Paul A. Johnsgard, Aaron T. Pearse Jan 2017

Review Of A Chorus Of Cranes: The Cranes Of North America And The World By Paul A. Johnsgard, Aaron T. Pearse

United States Geological Survey: Staff Publications

Cranes (Gruidae) are widely distributed throughout the world, have lived on Earth for several million years, and currently reside on five continents. Archaeological evidence and historical references suggest that humans have interacted with and been captivated by cranes for many thousands of years (e.g., Leslie 1988, Muellner 1990). A glimpse of our reverence for these birds can be found in A Chorus of Cranes by Paul A. Johnsgard, with photographs by Thomas D. Mangelsen. Many species of cranes are currently identified as threatened or endangered, and their future will likely rest in the hands of humans; this book presents their …


Variation In Δ15N And Δ13C Values Of Forages For Arctic Caribou: Effects Of Location, Phenology And Simulated Digestion, Lindsay L. Vansomeren, Perry S. Barboza, David D. Gustine, M. Syndonia Bret-Harte Jan 2017

Variation In Δ15N And Δ13C Values Of Forages For Arctic Caribou: Effects Of Location, Phenology And Simulated Digestion, Lindsay L. Vansomeren, Perry S. Barboza, David D. Gustine, M. Syndonia Bret-Harte

United States Geological Survey: Staff Publications

RATIONALE: The use of stable isotopes for dietary estimates of wildlife assumes that there are consistent differences in isotopic ratios among diet items, and that the differences in these ratios between the diet item and the animal tissues (i.e., fractionation) are predictable. However, variation in isotopic ratios and fractionation of δ13C and δ15N values among locations, seasons, and forages are poorly described for arctic herbivores especially migratory species such as caribou (Rangifer tarandus).

METHODS: We measured the δ13Cand δ15N values of seven species of forage growing along a 200-km …


Assessment Of Frequency And Duration Of Point Counts When Surveying For Golden Eagle Presence, Ben R. Skipper, Clint W. Boal, Jo-Szu Tsai, Mark R. Fuller Jan 2017

Assessment Of Frequency And Duration Of Point Counts When Surveying For Golden Eagle Presence, Ben R. Skipper, Clint W. Boal, Jo-Szu Tsai, Mark R. Fuller

United States Geological Survey: Staff Publications

We assessed the utility of the recommended golden eagle (Aquila chrysaetos) survey methodology in the U.S. Fish and Wildlife Service 2013 Eagle Conservation Plan Guidance. We conducted 800-m radius, 1-hr point-count surveys broken into 20-min segments, during 2 sampling periods in 3 areas within the Intermountain West of the United States over 2 consecutive breeding seasons during 2012 and 2013. Our goal was to measure the influence of different survey time intervals and sampling periods on detectability and use estimates of golden eagles among different locations. Our results suggest that a less intensive effort (i.e., survey duration shorter …


Flood Effects Provide Evidence Of An Alternate Stable State From Dam Management On The Upper Missouri River, K. Skalak, A. Benthem, C. Hupp, E. Schenk, J. Galloway, R. Nustad Jan 2017

Flood Effects Provide Evidence Of An Alternate Stable State From Dam Management On The Upper Missouri River, K. Skalak, A. Benthem, C. Hupp, E. Schenk, J. Galloway, R. Nustad

United States Geological Survey: Staff Publications

We examine how historic flooding in 2011 affected the geomorphic adjustments created by dam regulation along the approximately 120 km free flowing reach of the Upper Missouri River bounded upstream by the Garrison Dam (1953) and downstream by Lake Oahe Reservoir (1959) near the City of Bismarck, ND, USA. The largest flood since dam regulation occurred in 2011. Flood releases from the Garrison Dam began in May 2011 and lasted until October, peaking with a flow of more than 4200m3 s-1. Channel cross-section data and aerial imagery before and after the flood were compared with historic rates …


Micronuclei And Other Erythrocyte Nuclear Abnormalities In Fishes From The Great Lakes Basin,Usa, Ryan P. Braham, Vicki S. Blazer, Cassidy H. Shaw, Patricia M. Mazik Jan 2017

Micronuclei And Other Erythrocyte Nuclear Abnormalities In Fishes From The Great Lakes Basin,Usa, Ryan P. Braham, Vicki S. Blazer, Cassidy H. Shaw, Patricia M. Mazik

United States Geological Survey: Staff Publications

Biological markers (biomarkers) sensitive to genotoxic and mutagenic contamination in fishes are widely used to identify exposure effects in aquatic environments. The micronucleus assay was incorporated into a suite of indicators to assess exposure to genotoxic and mutagenic contamination at five Great Lakes Areas of Concern (AOCs), as well as one non-AOC (reference) site. The assay allowed enumeration of micronuclei as well as other nuclear abnormalities for both site and species comparisons. Erythrocyte abnormality data was also compared to skin and liver tumor prevalence and hepatic transcript abundance. Erythrocyte abnormalities were observed at all sites with variable occurrence and severity …


Challenges For Creating A Site-Specific Groundwater-Use Record For The Ozark Plateaus Aquifer System (Central Usa) From 1900 To 2010, Katherine J. Knierim, Anna M. Nottmeier, Scott Worland, Drew A. Westerman, Brian R. Clark Jan 2017

Challenges For Creating A Site-Specific Groundwater-Use Record For The Ozark Plateaus Aquifer System (Central Usa) From 1900 To 2010, Katherine J. Knierim, Anna M. Nottmeier, Scott Worland, Drew A. Westerman, Brian R. Clark

United States Geological Survey: Staff Publications

Hydrologic budgets to determine groundwater availability are important tools for water-resource managers. One challenging component for developing hydrologic budgets is quantifying water use through time because historical and site-specific water-use data can be sparse or poorly documented. This research developed a groundwater-use record for the Ozark Plateaus aquifer system (central USA) from 1900 to 2010 that related county-level aggregated water-use data to site-specific well locations and aquifer units. A simple population-based linear model, constrained to 0 million liters per day in 1900, provided the best means to extrapolate groundwater-withdrawal rates pre-1950s when there was a paucity of water-use data. To …


Habitat Mosaics And Path Analysis Can Improve Biological Conservation Of Aquatic Biodiversity In Ecosystems With Low-Head Dams, Sean M. Hitchman, Martha E. Mather, Joseph M. Smith, Jane S. Fencl Jan 2017

Habitat Mosaics And Path Analysis Can Improve Biological Conservation Of Aquatic Biodiversity In Ecosystems With Low-Head Dams, Sean M. Hitchman, Martha E. Mather, Joseph M. Smith, Jane S. Fencl

United States Geological Survey: Staff Publications

Conserving native biodiversity depends on restoring functional habitats in the face of human-induced disturbances. Low-head dams are a ubiquitous human impact that degrades aquatic ecosystems worldwide. To improve our understanding of how low-head dams impact habitat and associated biodiversity, our research examined complex interactions among three spheres of the total environment. i.e., how low-head dams (anthroposphere) affect aquatic habitat (hydrosphere), and native biodiversity (biosphere) in streams and rivers. Creation of lake-like habitats upstream of low-head dams is a well-documented major impact of dams. Alterations downstream of low head dams also have important consequences, but …


Temporal Shift Of Sea Turtle Nest Sites In An Eroding Barrier Island Beach, Ikuko Fujisaki, Margaret Lamont, Ray Carthy Jan 2017

Temporal Shift Of Sea Turtle Nest Sites In An Eroding Barrier Island Beach, Ikuko Fujisaki, Margaret Lamont, Ray Carthy

United States Geological Survey: Staff Publications

Shoreline changes affect functionality of a sandy beach as a wildlife habitat and coastal erosion is among the primary causes of the changes. We examined temporal shifts in locations where loggerheads placed nests in relation to coastal erosion along a barrier island beach in the northern Gulf of Mexico. We first confirmed consistency in long-term (1855–2001), short-term (1976–2001), and more recent (2002–2012) shoreline change rates in two adjacent beach sections, one historically eroding (west beach) and the other accreting (east beach). The mean annual shoreline change rate in the two sections was significantly different in all time periods. The recent …


Degradation Of Crude 4‑Mchm (4-Methylcyclohexanemethanol) In Sediments From Elk River, West Virginia, Isabelle M. Cozzarelli, Denise M. Akob, Mary Jo Baedecker, Tracey Spencer, Jeanne Jaeschke, Darren S. Dunlap, Adam C. Mumford, Amisha T, Poret-Peterson, Douglas B. Chambers Jan 2017

Degradation Of Crude 4‑Mchm (4-Methylcyclohexanemethanol) In Sediments From Elk River, West Virginia, Isabelle M. Cozzarelli, Denise M. Akob, Mary Jo Baedecker, Tracey Spencer, Jeanne Jaeschke, Darren S. Dunlap, Adam C. Mumford, Amisha T, Poret-Peterson, Douglas B. Chambers

United States Geological Survey: Staff Publications

In January 2014, approximately 37 800 L of crude 4-methylcyclohexanemethanol (crude MCHM) spilled into the Elk River, West Virginia. To understand the long-term fate of 4-MCHM, we conducted experiments under environmentally relevant conditions to assess the potential for the 2 primary compounds in crude MCHM (1) to undergo biodegradation and (2) for sediments to serve as a long-term source of 4-MCHM. We developed a solid phase microextraction (SPME) method to quantify the cis- and transisomers of 4-MCHM. Autoclaved Elk River sediment slurries sorbed 17.5% of cis-4-MCHM and 31% of trans-4-MCHM from water during the 2-week experiment. …


Design Tradeoffs In Long-Term Research For Stream Salamanders, Adrianne B. Brand, Evan H. Campbell Grant Jan 2017

Design Tradeoffs In Long-Term Research For Stream Salamanders, Adrianne B. Brand, Evan H. Campbell Grant

United States Geological Survey: Staff Publications

Long-term research programs can benefit from early and periodic evaluation of their ability to meet stated objectives. In particular, consideration of the spatial allocation of effort is key. We sampled 4 species of stream salamanders intensively for 2 years (2010–2011) in the Chesapeake and Ohio Canal National Historical Park, Maryland, USA to evaluate alternative distributions of sampling locations within stream networks, and then evaluated via simulation the ability of multiple survey designs to detect declines in occupancy and to estimate dynamic parameters (colonization, extinction) over 5 years for 2 species. We expected that fine scale microhabitat variables (e.g., cobble, detritus) …


Floristic Quality Index And Forested Floristic Quality Index: Assessment Tools For Restoration Projects And Monitoring Sites In Coastal Louisiana, Kari F. Cretini, William B. Wood, Jenneke M. Visser, Ken W. Krauss, Leigh Anne Sharp, Gregory D. Steyer, Gary P. Shaffer, Sarai C. Piazza Jan 2017

Floristic Quality Index And Forested Floristic Quality Index: Assessment Tools For Restoration Projects And Monitoring Sites In Coastal Louisiana, Kari F. Cretini, William B. Wood, Jenneke M. Visser, Ken W. Krauss, Leigh Anne Sharp, Gregory D. Steyer, Gary P. Shaffer, Sarai C. Piazza

United States Geological Survey: Staff Publications

In 2003, the Coastwide Reference Monitoring System (CRMS) program was established in coastal Louisiana marshes and swamps to assess the effectiveness of individual coastal restoration projects and the cumulative effects of multiple projects at regional and coastwide scales (Steyer et al., 2003). In order to make these assessments, analytical teams were assembled for each of the primary data types sampled under theCRMS program, including vegetation, hydrology, landscape, and soils. These teams consisted of scientists and support staff from the US Geological Survey and other federal agencies, the Coastal Protection and Restoration Authority of Louisiana, and university academics. Each team was …


Linking Animals Aloft With The Terrestrial Landscape, Jeffrey J. Buler, Wylie C. Barrow Jr., Matthew E. Boone, Deanna K. Dawson, Robert H. Diehl, Frank R. Moore, Lori A. Randall, Timothy D. Schreckengost, Jaclyn A. Smolinsky Jan 2017

Linking Animals Aloft With The Terrestrial Landscape, Jeffrey J. Buler, Wylie C. Barrow Jr., Matthew E. Boone, Deanna K. Dawson, Robert H. Diehl, Frank R. Moore, Lori A. Randall, Timothy D. Schreckengost, Jaclyn A. Smolinsky

United States Geological Survey: Staff Publications

Despite using the aerosphere for many facets of their life, most flying animals (i.e., birds, bats, some insects) are still bound to terrestrial habitats for resting, feeding, and reproduction. Comprehensive broad-scale observations by weather surveillance radars of animals as they leave terrestrial habitats for migration or feeding flights can be used to map their terrestrial distributions either as point locations (e.g., communal roosts) or as continuous surface layers (e.g., animal densities in habitats across a landscape). We discuss some of the technical challenges to reducing measurement biases related to how radars sample the aerosphere and the flight behavior of animals. …


Extending The Habitat Concept To The Airspace, Robert H. Diehl, Anna C. Peterson, Rachel T. Bolus, Douglas Johnson Jan 2017

Extending The Habitat Concept To The Airspace, Robert H. Diehl, Anna C. Peterson, Rachel T. Bolus, Douglas Johnson

United States Geological Survey: Staff Publications

Habitat is one of the most familiar and fundamental concepts in the fields of ecology, animal behavior, and wildlife conservation and management. Humans interact with habitats through their senses and experiences and education to such a degree that their perceptions of habitat have become second nature. For this reason, it may be difficult at first to accept the airspace as habitat, an area that is invisible, untouchable, highly dynamic, and its occupants difficult to see. Nonetheless, the habitat concept, by definition and in practice, applies readily to the airspace. Some ecological and behavioral processes including habitat selection, foraging, and reproduction …


Linking Animals Aloft With The Terrestrial Landscape, Jeffrey J. Buler, Wylie C. Barrow Jr., Matthew E. Boone, Deanna K. Dawson, Robert H. Diehl, Frank R. Moore, Lori A. Randall, Timothy D. Schreckengost, Jaclyn A. Smolinsky Jan 2017

Linking Animals Aloft With The Terrestrial Landscape, Jeffrey J. Buler, Wylie C. Barrow Jr., Matthew E. Boone, Deanna K. Dawson, Robert H. Diehl, Frank R. Moore, Lori A. Randall, Timothy D. Schreckengost, Jaclyn A. Smolinsky

United States Geological Survey: Staff Publications

Despite using the aerosphere for many facets of their life, most flying animals (i.e., birds, bats, some insects) are still bound to terrestrial habitats for resting, feeding, and reproduction. Comprehensive broad-scale observations by weather surveillance radars of animals as they leave terrestrial habitats for migration or feeding flights can be used to map their terrestrial distributions either as point locations (e.g., communal roosts) or as continuous surface layers (e.g., animal densities in habitats across a landscape). We discuss some of the technical challenges to reducing measurement biases related to how radars sample the aerosphere and the flight behavior of animals. …


Extending The Habitat Concept To The Airspace, Robert H. Diehl, Anna C. Peterson, Rachel T. Bolus, Douglas Johnson Jan 2017

Extending The Habitat Concept To The Airspace, Robert H. Diehl, Anna C. Peterson, Rachel T. Bolus, Douglas Johnson

United States Geological Survey: Staff Publications

Habitat is one of the most familiar and fundamental concepts in the fields of ecology, animal behavior, and wildlife conservation and management. Humans interact with habitats through their senses and experiences and education to such a degree that their perceptions of habitat have become second nature. For this reason, it may be difficult at first to accept the airspace as habitat, an area that is invisible, untouchable, highly dynamic, and its occupants difficult to see. Nonetheless, the habitat concept, by definition and in practice, applies readily to the airspace. Some ecological and behavioral processes including habitat selection, foraging, and reproduction …


Water-Level And Recoverable Water In Storage Changes, High Plains Aquifer, Predevelopment To 2015 And 2013–15, Virginia L. Mcguire Jan 2017

Water-Level And Recoverable Water In Storage Changes, High Plains Aquifer, Predevelopment To 2015 And 2013–15, Virginia L. Mcguire

United States Geological Survey: Staff Publications

The High Plains aquifer underlies 111.8 million acres (about 175,000 square miles) in parts of eight States—Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. Water-level declines began in parts of the High Plains aquifer soon after the beginning of substantial irrigation with groundwater in the aquifer area (about 1950). This report presents water-level changes and change in recoverable water in storage in the High Plains aquifer from predevelopment (about 1950) to 2015 and from 2013 to 2015.

The methods to calculate area-weighted, average water-level changes; change in recoverable water in storage; and total recoverable water in storage …


Key Differences Between Lakes And Reservoirs Modify Climate Signals: A Case For A New Conceptual Model, Nicole M. Hayes, Bridget R. Deemer, Jessica R. Corman, N. Roxanna Razavi, Kristin E. Strock Jan 2017

Key Differences Between Lakes And Reservoirs Modify Climate Signals: A Case For A New Conceptual Model, Nicole M. Hayes, Bridget R. Deemer, Jessica R. Corman, N. Roxanna Razavi, Kristin E. Strock

United States Geological Survey: Staff Publications

Lakes and reservoirs are recognized as important sentinels of climate change, integrating catchment and atmospheric climate change drivers. Climate change conceptual models generally consider lakes and reservoirs together despite the possibility that these systems respond differently to climate-related drivers. Here, we synthesize differences between lake and reservoir characteristics that are likely important for predicting waterbody response to climate change. To better articulate these differences, we revised the energy mass flux framework, a conceptual model for the effects of climate change on lentic ecosystems, to explicitly consider the differential responses of lake versus reservoir ecosystems. The model predicts that catchment and …


Climate Change Adaptation For Southern California Groundwater Managers: A Case Study Of The Six Basins Aquifer, Frank Lyles Jan 2017

Climate Change Adaptation For Southern California Groundwater Managers: A Case Study Of The Six Basins Aquifer, Frank Lyles

Pomona Senior Theses

Groundwater has been very important to the economic development of Southern California, and will continue to be a crucial resource in the 21st century. However, Climate Change threatens to disrupt many of the physical and economic processes that control the flow of water in and out of aquifers. One groundwater manager, the Six Basins Watermaster in eastern Los Angeles and western San Bernardino Counties, has developed a long-term planning document called the Strategic Plan that mostly fails to address the implications of Climate Change, especially for local water supplies. This thesis presents an in-depth analysis of the Six Basin Watermaster’s …


Modern Fair-Weather And Storm Sediment Transport Around Ship Island, Mississippi: Implications For Coastal Habitats And Restoration Efforts, Eve Rettew Eisemann Dec 2016

Modern Fair-Weather And Storm Sediment Transport Around Ship Island, Mississippi: Implications For Coastal Habitats And Restoration Efforts, Eve Rettew Eisemann

Master's Theses

The Mississippi – Alabama barrier island chain is experiencing accelerated sea level rise, decreased sediment supply, and frequent hurricane impacts. These three factors drive unprecedented rates of morphology change and ecosystem reduction. All islands in the chain have experienced land loss on the order of hectares per year since records began in the 1840s. In 1969, Hurricane Camille impacted as a Category 5, breaching Ship Island, and significantly reduced viable seagrass habitat. Hurricane Katrina impacted as a Category 3 in 2005, further widening Camille Cut. To better understand the sustainability of these important islands and the ecosystems they support, sediment …


Modeling The Effects Of Tile Drain Placement On The Hydrologic Function Of Farmed Prairie Wetlands1, Brett Werner, John Tracy, W. Carter Johnson, Richard A. Voldseth, Glenn R. Guntenspergen, Bruce Millett Dec 2016

Modeling The Effects Of Tile Drain Placement On The Hydrologic Function Of Farmed Prairie Wetlands1, Brett Werner, John Tracy, W. Carter Johnson, Richard A. Voldseth, Glenn R. Guntenspergen, Bruce Millett

United States Geological Survey: Staff Publications

The early 2000s saw large increases in agricultural tile drainage in the eastern Dakotas of North America. Agricultural practices that drain wetlands directly are sometimes limited by wetland protection programs. Little is known about the impacts of tile drainage beyond the delineated boundaries of wetlands in upland catchments that may be in agricultural production. A series of experiments were conducted using the well-published model WETLANDSCAPE that revealed the potential for wetlands to have significantly shortened surface water inundation periods and lower mean depths when tile is placed in certain locations beyond the wetland boundary. Under the soil conditions found in …


Groundwater Declines Are Linked To Changes In Great Plains Stream Fish Assemblages, Joshuah S. Perkin, Keith B. Gido, Jeffrey A. Falke, Kurt D. Fausch, Harry Crockett, Eric R. Johnson, John Sanderson Nov 2016

Groundwater Declines Are Linked To Changes In Great Plains Stream Fish Assemblages, Joshuah S. Perkin, Keith B. Gido, Jeffrey A. Falke, Kurt D. Fausch, Harry Crockett, Eric R. Johnson, John Sanderson

United States Geological Survey: Staff Publications

Groundwater pumping for agriculture is a major driver causing declines of global freshwater ecosystems, yet the ecological consequences for stream fish assemblages are rarely quantified. We combined retrospective (1950–2010) and prospective (2011–2060) modeling approaches within a multiscale framework to predict change in Great Plains stream fish assemblages associated with groundwater pumping from the United States High Plains Aquifer. We modeled the relationship between the length of stream receiving water from the High Plains Aquifer and the occurrence of fishes characteristic of small and large streams in the western Great Plains at a regional scale and for six subwatersheds nested within …


Holocene Glacial Activity In Barilari Bay, West Antarctic Peninsula, Tracked By Magnetic Mineral Assemblages: Linking Ice, Ocean, And Atmosphere, Brendan Reilly, Carl Natter, Stefanie A. Brachfeld Nov 2016

Holocene Glacial Activity In Barilari Bay, West Antarctic Peninsula, Tracked By Magnetic Mineral Assemblages: Linking Ice, Ocean, And Atmosphere, Brendan Reilly, Carl Natter, Stefanie A. Brachfeld

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

We investigate the origin and fate of lithogenic sediments using magnetic mineral assemblages in Barilari Bay, west Antarctic Peninsula (AP) from sediment cores recovered during the Larsen Ice Shelf System, Antarctica (LARISSA) NBP10-01 cruise. To quantify and reconstruct Holocene changes in covarying magnetic mineral assemblages, we adopt an unsupervised mathematical unmixing strategy and apply it to measurements of magnetic susceptibility as a function of increasing temperature. Comparisons of the unmixed end-members with magnetic observations of northwestern AP bedrock and the spatial distribution of magnetic mineral assemblages within the fjord, allow us to identify source regions, including signatures for ‘‘inner bay,’’ …


Germination And Growth Of Native And Invasive Plants On Soil Associated With Biological Control Of Tamarisk (Tamarix Spp.), Rebecca A. Sherry, Patrick B. Shafroth, Jayne Belnap, Steven Ostoja, Sasha C. Reed Nov 2016

Germination And Growth Of Native And Invasive Plants On Soil Associated With Biological Control Of Tamarisk (Tamarix Spp.), Rebecca A. Sherry, Patrick B. Shafroth, Jayne Belnap, Steven Ostoja, Sasha C. Reed

United States Geological Survey: Staff Publications

Introductions of biocontrol beetles (tamarisk beetles) are causing dieback of exotic tamarisk in riparian zones across the western United States, yet factors that determine plant communities that follow tamarisk dieback are poorly understood. Tamarisk-dominated soils are generally higher in nutrients, organic matter, and salts than nearby soils, and these soil attributes might influence the trajectory of community change. To assess physical and chemical drivers of plant colonization after beetle-induced tamarisk dieback, we conducted separate germination and growth experiments using soil and litter collected beneath defoliated tamarisk trees. Focal species were two common native (red threeawn, sand dropseed) and two common …


An Early Paleogene Palynological Assemblage From The Sabrina Coast, East Antarctica: New Species And Implications For Depositional History, Catherine Davies Smith Nov 2016

An Early Paleogene Palynological Assemblage From The Sabrina Coast, East Antarctica: New Species And Implications For Depositional History, Catherine Davies Smith

USF Tampa Graduate Theses and Dissertations

Palynological analyses of 13 samples from two sediment cores retrieved from the Sabrina Coast, East Antarctica, provide the first information regarding the paleovegetation within the Aurora Subglacial Basin. The assemblages, hereafter referred to as the Sabrina Flora, are dominated by angiosperms, with complexes of Gambierina (G.) rudata and G. edwardsii representing 38–66% of the assemblage and an abundant and diverse Proteaceae component. The Sabrina Flora also includes Battenipollis sectilis, Forcipites sp. and Nothofagidites spp. (mostly belonging to the N. cf. rocaensis-flemingii complex), along with a few fern spores, including Laevigatosporites ovatus, a moderate presence of conifers, and …


Abundance Of Archaias Angulatus On The West Florida Coast Indicates The Influence Of Carbonate Alkalinity Over Salinity, Sean Thomas Beckwith Oct 2016

Abundance Of Archaias Angulatus On The West Florida Coast Indicates The Influence Of Carbonate Alkalinity Over Salinity, Sean Thomas Beckwith

USF Tampa Graduate Theses and Dissertations

Archaias angulatus, a large symbiont-bearing foraminifer (Order Miliolida) that produces a Mg-calcite shell, is common throughout the Caribbean and warm western Atlantic region. This species lives abundantly in seagrass beds along the Springs Coast of northwest Florida (up to 4 adults per gram of sediment) where spring-fed rivers emerge from a limestone aquifer, and in Florida Bay to the southeast (25 adults/g) where the sediment is primarily biogenic carbonate. In contrast, live specimens are seldom found in the seagrass beds along the central-west coast of Florida, where barrier islands are dominated by quartz sand. My working hypothesis is that substratum …


A Complex Origin For The Kelso Dunes, Mojave National Preserve, California, Usa: A Case Study Using A Simple Geochemical Method With Global Applications, Daniel R. Muhs, Nicholas Lancaster, Gary L. Skipp Oct 2016

A Complex Origin For The Kelso Dunes, Mojave National Preserve, California, Usa: A Case Study Using A Simple Geochemical Method With Global Applications, Daniel R. Muhs, Nicholas Lancaster, Gary L. Skipp

United States Geological Survey: Staff Publications

The Kelso Dune field in southern California is intriguing because although it is of limited areal extent (~100 km2), it has a wide variety of dune forms and contains many active dunes (~40 km2), which is unusual in the Mojave Desert. Studies over the past eight decades have concluded that the dunes are derived primarily from a single source, Mojave River alluvium, under a dominant, westerly-to-northwesterly wind regime. The majority of these studies did not, however, present data to support the Mojave River as the only source.We conducted mineralogical and geochemical studies ofmost of the 14 geomorphically defined dune groups …


Status Of Scientific Knowledge, Recovery Progress, And Future Research Directions For The Gulf Sturgeon, Acipenser Oxyrinchus Desotoi Vladykov, 1955, K.J. Sulak, F. Parauka, W. T. Slack, R. T. Ruth, M. T. Randall, K. Luke, M. E. Price Sep 2016

Status Of Scientific Knowledge, Recovery Progress, And Future Research Directions For The Gulf Sturgeon, Acipenser Oxyrinchus Desotoi Vladykov, 1955, K.J. Sulak, F. Parauka, W. T. Slack, R. T. Ruth, M. T. Randall, K. Luke, M. E. Price

United States Geological Survey: Staff Publications

The Gulf Sturgeon, Acipenser oxyrinchus desotoi, is an anadromous species of Acipenseridae and native to North America. It currently inhabits and spawns in the upper reaches of seven natal rivers along the northern coast of the Gulf of Mexico from the Suwannee River, Florida, to the Pearl River, Louisiana, during spring to autumn. Next to the Alligator Gar (Atractosteus spatula), the Gulf Sturgeon is currently the largest fish species occurring in U.S. Gulf Coast rivers, attaining a length of 2.35 m and weights exceeding 135 kg, but historically attained a substantially larger size. Historically, the spawning populations existed in additional …


On The Importance Of Stratigraphic Control For Vertebrate Fossil Sites In Channel Islands National Park, California, Usa: Examples From New Mammuthus Finds On San Miguel Island, Jeffrey S. Pigati, Daniel R. Muhs, John P. Mcgeehin Sep 2016

On The Importance Of Stratigraphic Control For Vertebrate Fossil Sites In Channel Islands National Park, California, Usa: Examples From New Mammuthus Finds On San Miguel Island, Jeffrey S. Pigati, Daniel R. Muhs, John P. Mcgeehin

United States Geological Survey: Staff Publications

Quaternary vertebrate fossils, most notably mammoth remains, are relatively common on the northern Channel Islands of California. Well-preserved cranial, dental, and appendicular elements of Mammuthus exilis (pygmy mammoth) and Mammuthus columbi (Columbian mammoth) have been recovered from hundreds of localities on the islands during the past half-century or more. Despite this paleontological wealth, the geologic context of the fossils is described in the published literature only briefly or not at all, which has hampered the interpretation of associated 14C ages and reconstruction of past environmental conditions. We recently discovered a partial tusk, several large bones, and a tooth enamel plate …