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At least 703 records · Page 39Linked to original sources

USGS2017

Assessment of frequency and duration of point counts when surveying for golden eagle presence

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 than 1 hr and point-count survey radii smaller than 800 m) would likely be inadequate for rigorous documentation of golden eagle occurrence pre- or postconstruction of wind energy facilities. Results from a simulation analysis of detection probabilities and survey effort suggest that greater temporal and spatial effort could make point-count surveys more applicable for evaluating golden eagle occurrence in survey areas; however, increased effort would increase financial costs associated with additional person-hours and logistics (e.g., fuel, lodging). Future surveys can benefit from a pilot study and careful consideration of prior information about counts or densities of golden eagles in the survey area before developing a survey design. If information is lacking, survey planning may be best served by assuming low detection rates and increasing the temporal and spatial effort.

Idaho, New Mexico, Wyoming↗

USGS2021

Fire and forests in the 21st century: Managing resilience under changing climates and fire regimes in USA forests

Higher temperatures, lower snowpacks, drought, and extended dry periods have contributed to increased wildfire activity in recent decades. Climate change is expected to increase the frequency of large fires, the cumulative area burned, and fire suppression costs and risks in many areas of the USA. Fire regimes are likely to change due to interactions among climate, fire, and other stressors and disturbances; resulting in persistent changes in forest structure and function. The remainder of the twenty-first century will present substantial challenges, as natural resource managers are faced with higher fire risk and the difficult task of maintaining ecological function in a rapidly changing biophysical and social landscape. Fuel treatments will continue to be important for minimizing the undesirable ecological effects of fire, and for enhancing firefighter safety; however, treatments must be implemented strategically across large areas. Collaboration among agencies, private landowners, and other organizations will be critical for ensuring resilience and sustainable forest management.

Book chapter↗

USGS2025

Macroseismology

In this chapter I discuss the use of so-called macroseismic data, i.e., reports of damage and other effects of shaking on humans and the built environment, to improve the characterization of earthquakes and the ground motions they produce. Macroseismic data are critical not only to investigate earthquakes that occurred before the start of the instrumental era in seismology, but are also, by virtue of the spatially rich nature of the data, of tremendous potential importance to investigate early instrumental and even recent earthquakes. Fueled by both the advent of on-line systems that now produce unprecedented volumes of macroseismic intensity data and by recognition of the importance of understanding key historical earthquakes, there has been a growing appreciation for the value of macroseismic data. It is, however, critical to understand both the unique challenges and the unique opportunities associated with these data. I review the evolution of thought and practices regarding analysis of macroseismic data, and the use of such data to improve the characterization of historic and early instrumental earthquakes.

Book chapter↗

USGS2017

Uncertainties in forecasting the response of polar bears to global climate change

Several sources of uncertainty affect how precisely the future status of polar bears ( Ursus maritimus ) can be forecasted. Foremost are unknowns about the future levels of global greenhouse gas emissions, which could range from an unabated increase to an aggressively mitigated reduction. Uncertainties also arise because different climate models project different amounts and rates of future warming (and sea ice loss)—even for the same emission scenario. There are also uncertainties about how global warming could affect the Arctic Ocean’s food web, so even if climate models project the presence of sea ice in the future, the availability of polar bear prey is not guaranteed. Under a worst-case emission scenario in which rates of greenhouse gas emissions continue to rise unabated to century’s end, the uncertainties about polar bear status center on a potential for extinction. If the species were to persist, it would likely be restricted to a high-latitude refugium in northern Canada and Greenland—assuming a food web also existed with enough accessible prey to fuel weight gains for surviving onshore during the most extreme years of summer ice melt. On the other hand, if emissions were to be aggressively mitigated at the levels proposed in the Paris Climate Agreement, healthy polar bear populations would probably continue to occupy all but the most southern areas of their contemporary summer range. While polar bears have survived previous warming phases—which indicate some resiliency to the loss of sea ice habitat—what is certain is that the present pace of warming is unprecedented and will increasingly expose polar bears to historically novel stressors.

Book chapter↗

USGS2013

Limiting the immediate and subsequent hazards associated with wildfires

Wildfire is a unique natural hazard because it poses immediate threats to life and property as well as creating conditions that can lead to subsequent debris flows. In recent years, the immediate destructive force of wildfires has been decreased through better understanding of fire behavior. Lightning detection networks now identify the number and locations of this common ignition source. Measurements of wind speed, temperature, slope, fuel types and fire boundaries are routinely incorporated into models for fire spread, permitting real-time adjustments to fire-fighting strategies, thus increasing fire-fighting effectiveness. Similarly, our capability to limit impacts from post-fire debris flows is improving. Empirical models for estimating the probability of debris-flow occurrence, the volume of such an event, and mapping the inundated area, linked with improved definitions of the rainfall conditions that trigger debris flows, can be used to provide critical information for post-fire hazard mitigation and emergency-response planning.

Book chapter↗

USGS2012

The principal rare earth elements deposits of the United States: A summary of domestic deposits and a global perspective

Demand for the rare earth elements (REE, lanthanide elements) is estimated to be increasing at a rate of about 8% per year due to increasing applications in consumer products, computers, automobiles, aircraft, and other advanced technology products. Much of this demand growth is driven by new technologies that increase energy efficiency and substitute away from fossil fuels. Production of these elements is highly concentrated in China, which is reducing its exports of REE raw materials as part of its industrial policy. The ability of the rest of the world to replace supply from China depends on the quality of known REE resources and the degree to which those resources have been explored and evaluated. A review of United States resources in a global context finds that the United States could make significant contributions to future REE production. Aside from two advanced projects in the United States and Australia, however, there are no REE projects advanced enough to meet short-term demand.

Book chapter↗

USGS2013

Regional assessment of North America: Urbanization trends, biodiversity patterns, and ecosystem services

North America contains some of the most urbanized landscapes in the world. In the United States (U.S.) and Canada, approximately 80 % of the population is urban, with Mexico slightly less (Kaiser Family Foundation 2013). Population growth combined with economic growth has fueled recent urban land expansion in North America. Between 1970 and 2000, urban land area expanded at a rate of 3.31 % (Seto et al. 2011) creating unique challenges for conserving biodiversity and maintaining regional and local ecosystem services.

Book chapter↗

USGS1993

Distribution and mode of occurrence of selenium in US coals

Selenium excess and deficiency have been established as the cause of various health problems in man and animals. Combustion of fossil fuels, especially coal, may be a major source of the anthropogenic introduction of selenium in the environment. Coal is enriched in selenium relative to selenium's concentration in most other rocks and relative to selenium in the Earth's crust. Data from almost 9,000 coal samples have been used to determine the concentration and distribution of selenium in US coals. The geometric mean concentration of selenium in US coal is 1.7 ppm. The highest mean selenium value (geometric mean 4.7 ppm) is in the Texas Region. Atlantic Coast (Virginia and North Carolina) and Alaska coals have the lowest geometric means (0.2 and 0.42 ppm, respectively). All western coal regions have mean selenium concentrations of less than 2.0 ppm. In contrast, all coal basins east of the Rocky Mountains (except for several small basins in Rhode Island, Virginia, and North Carolina) have mean selenium values of 1.9 or greater. Generally, variations in selenium concentration do not correlate with variations in ash yield, pyritic sulphur, or organic sulphur concentrations. This may be the result of multiple sources of selenium; however, in some non-marine basins with restricted sources of selenium, selenium has positive correlations with other coal quality parameters. Selenium occurs in several forms in coal but appears to be chiefly associated with the organic fraction, probably substituting for organic sulphur. Other important forms of selenium in coal are selenium-bearing pyrite, selenium-bearing galena, and lead selenide (clausthalite). Water-soluble and ion-exchangeable selenium also have been reported. ?? 1993 Copyright Science and Technology Letters.

Environmental Geochemistry and Health↗

USGS1986

Fire adaptation in Neblinaria celiae (Theaceae), a high-elevation rosette shrub endemic to a wet equatorial tepui

Neblinaria celiae (Theaceae), a rosette shrub endemic to the exceedingly rainy summit of remote Cerro de la Neblina in southern Venezuela, has a previously undescribed set of adaptations to fire. Its growth form entails sparse branching, massive terminal leaf rosettes, and thick bark. It is highly fire-tolerant, with a survival rate of 93% in a stand recently ignited by lightning, vs. 0% in seven co-occurring woody species. Survival increases sharply with rosette height, favoring a sparsely branched habit that would maximize the rate of upward growth through the sparse fuel layer supported by a sterile substrate. Thick bark and massive rosettes help protect cambial and foliar meristems from brief exposure to high temperatures. Rosettes on shorter plants are exposed to greater damage from fire near the ground and, as expected, are bigger and impound more rainwater; the greater number of leaves nearly balances the greater leaf mortality caused by fire. We relate Neblinaria's growth form to its dominance atop Neblina, to a general model for the evolution of sparse branching, and to the evolution of growth form in other tepui plants.

Oecologia↗

USGS1985

Anomalous hydrogen emissions from the San Andreas fault observed at the Cienega Winery, central California

We began continuous monitoring of H2 concentration in soil along the San Andreas and Calaveras faults in central California in December 1980, using small H2/O2 fuel-cell sensors. Ten monitoring stations deployed to date have shown that anomalous H2 emissions take place occasionally in addition to diurnal changes. Among the ten sites, the Cienega Winery site has produced data that are characterized by very small diurnal changes, a stable baseline, and remarkably distinct spike-like H2 anomalies since its installation in July 1982. A major peak appeared on 1-10 November 1982, and another on 3 April 1983, and a medium peak on 1 November 1983. The occurrences of these peaks coincided with periods of very low seismicity within a radius of 50 km from the site. In order to methodically assess how these peaks are related to earthquakes, three H2 degassing models were examined. A plausible correlational pattern was obtained by using a model that (1) adopts a hemicircular spreading pattern of H2 along an incipient fracture plane from the hypocenter of an earthquake, (2) relies on the FeO-H2O reaction for H2 generation, and (3) relates the accumulated amount of H2 to the mass of serpentinization of underlying ophiolitic rocks; the mass was tentatively assumed to be proportional to the seismic energy of the earthquake. ?? 1985 Birkha??user Verlag.

Pure and Applied Geophysics PAGEOPH↗

USGS1982

Accumulation of 14C-naphthalene in the tissues of redhead ducks fed oil-contaminated crayfish

Crayfish, artificially contaminated with 14 C-naphthalene-5% water-soluble fraction of No. 2 fuel oil, were force-fed to one-year-old redhead ducks to determine the accumulation of petroleum hydrocarbons. The relative distribution of carbon-14 activity in the gall bladder containing bile, and fat were similar, and significantly greater (P < 0.05) than the activity in the blood, brain, liver, and kidney. There was a significant increase (P < 0.05) in the disintegrations per minute per gram (dpm/g) in the blood, brain, kidney, and liver between days 1 and 3 of feeding, indicating a progressive accumulation of carbon-14 activity (naphthalene and presumably its metabolites). There was no significant effect of sex or the interaction of the duration of feeding and sex on carbon-14 activity in any of the tissues. The low daily dose of petroleum hydrocarbons (a total of approximately 1.25 mg/day) received by the ducks from the crayfish and the relatively short feeding regimen did not cause any overt signs of toxicity in the ducks.

Archives of Environmental Contamination and Toxico↗

USGS1982

Unweathered and weathered aviation kerosine: Chemical characterization and effects on hatching success of duck eggs

Unweathered crude and refined oils are known to be very toxic to the embryos of aquatic birds (ALBERS 1977, 19781 SEARO et ale 1978, WHITE et al. 1979, McGILL & RICHMOND 1979, and others) but the toxicity of weathered petroleum is not as well established. The toxicity of Prudhoe Bay crude oil and No. 2 fuel oil to embryos of mallard ducks (Anas platyrhynchos) decreased only after 3 weeks and 2 weeks of weathering on a large container of fresh water (SZARO et al. 1980). Ten microliters (uL) of 4 week-old Libyan crude oil caused a significant increase in mortality among embryos of Louisiana herons (Hydranassa tricolor) but the same amount of fresh oil did not cause a significant increase in mortality. However, embryos of laughing gulls (Larus atricilla) were not significantly affected by I0 uL of 4 or 8 week-old weathered Libyan crude oil nor i0 UL of fresh oil (MACKO& KING 1980). Crude ell (i0 uL) recovered from the water surface (age unknown, but presumably slightly weathered) near the IXTOC-I oil spill site in the Gulf of Mexico did not significantly reduce the survival of mallard embryos by day 18 of incubation (D. HOFFMAN, unpublished data).

Bulletin of Environmental Contamination and Toxico↗

USGS1987

Wind energy development in California, USA

Windfarms have been developed rapidly in California in the last few years. The impetus has been a legislated goal to generate 10% of California's electricity by windpower by the year 2000, and generous state and federal tax incentives. Windpower is promoted as environmentally benign, which it is in traditional uses. The California program, however, is not traditional: it calls for centralized development of a magnitude sufficient to offset significant amounts of fossil fuels now used to generate electricity. Centralized windfarm development, as exemplified by the Altamont Pass, Tehachapi Mountains, and San Gorgonio Pass developments, involves major road building projects in erosion-sensitive terrain, effective closure of public lands, and other detrimental effects. A windfarm consisting of 200 turbines with 17-m rotors located in steep terrain 16 km from an existing corridor might occupy 235 ha and physically disturb 86 ha. With average annual wind speeds of 22.5 km/h, the farm would generate about 10??106 kWh/year at present levels of capacity. This annual production would offset 1% of one day's consumption of oil in California. To supply 10% of the state's electricity (at 1984 production rates) would require about 600,000 turbines of the type in common use today and would occupy more than 685,000 ha. It is likely that indirect effects would be felt in much larger areas and would include increased air and water pollution resulting from accelerated erosion, degradation of habitat of domestic and wild animals, damage to archaeological sites, and reduction of scenic quality of now-remote areas of the state. ?? 1987 Springer-Verlag New York Inc.

Environmental Management↗

USGS1977

Entropy, materials, and posterity

Materials and energy are the interdependent feedstocks of economic systems, and thermodynamics is their moderator. It costs energy to transform the dispersed minerals of Earth's crust into ordered materials and structures. And it costs materials to collect and focus the energy to perform work - be it from solar, fossil fuel, nuclear, or other sources. The greater the dispersal of minerals sought, the more energy is required to collect them into ordered states. But available energy can be used once only. And the ordered materials of industrial economies become disordered with time. They may be partially reordered and recycled, but only at further costs in energy. Available energy everywhere degrades to bound states and order to disorder - for though entropy may be juggled it always increases. Yet industry is utterly dependent on low entropy states of matter and energy, while decreasing grades of ore require ever higher inputs of energy to convert them to metals, with ever increasing growth both of entropy and environmental hazard. Except as we may prize a thing for its intrinsic qualities - beauty, leisure, love, or gold - low-entropy is the only thing of real value. It is worth whatever the market will bear, and it becomes more valuable as entropy increases. It would be foolish of suppliers to sell it more cheaply or in larger amounts than their own enjoyment of life requires, whatever form it may take. For this reason, and because of physical constraints on the availability of all low-entropy states, the recent energy crises is only the first of a sequence of crises to be expected in energy and materials as long as current trends continue. The apportioning of low-entropy states in a modern industrial society is achieved more or less according to the theory of competitive markets. But the rational powers of this theory suffer as the world grows increasingly polarized into rich, over-industrialized nations with diminishing resource bases and poor, supplier nations with little industry. The theory also discounts posterity, the more so as population density and percapita rates of consumption continue to grow. A new social, economic, and ecologic norm that leads to population control, conservation, and an apportionment of low-entropy states across the generations is needed to assure to posterity the options that properly belong to it as an important but voiceless constituency of the collectivity we call mankind. ?? 1977 Ferdinand Enke Verlag Stuttgart.

Geologische Rundschau↗

USGS1993

Summary of the mineral- and energy-resource endowment, BLM roswell resource area, east-central New Mexico

In this summary of two comprehensive resource reports produced by the U.S. Bureau of Mines and the U.S. Geological Survey for the U.S. Bureau of Land Management, we discuss the mineral- and energyresource endowment of the 14-millon-acre Roswell Resource Area, New Mexico, managed by the Bureau of Land Management. The Bureau and Survey reports result from separate studies that are compilations of published and unpublished data and integrate new findings on the geology, geochemistry, geophysics, mineral, industrial, and energy commodities, and resources for the seven-county area. The reports have been used by the Bureau of Land Management in preparation of the Roswell Resource Area Resource Management Plan, and will have future use in nationwide mineral- and energy-resource inventories and assessments, as reference and training documents, and as public-information tools. In the Roswell Resource Area, many metals, industrial mineral commodities, and energy resources are being, or have been, produced or prospected. These include metals and high-technology materials, such as copper, gold, silver, thorium, uranium and/or vanadium, rare-earth element minerals, iron, manganese, tungsten, lead, zinc, and molybdenum; industrial mineral resources, including barite, limestone/dolomite, caliche, clay, fluorspar, gypsum, scoria, aggregate, and sand and gravel; and fuels and associated resources, such as oil, gas, tar sand and heavy oil, coal, and gases associated with hydrocarbons. Other commodities that have yet to be identified in economic concentrations include potash, halite, polyhalite, anhydrite, sulfur, feldspar, building stone and decorative rock, brines, various gases associated with oil and gas exploration, and carbon dioxide. ?? 1993 Oxford University Press.

Nonrenewable Resources↗

USGS2001

Major brazilian gold deposits - 1982 to 1999

Brazil has been a major but intermittent producer of gold since its discovery in 1500. Brazil led the world in gold production during the 18th and early 19th centuries. From the late 19th century to the late 20th century, total mining company and garimpeiro production was small and relatively constant at about 5 to 8 t/year. The discovery of alluvial deposits in the Amazon by garimpeiros in the 1970s and the opening of eight mines by mining companies from 1983 to 1990 fueled a major boom in Brazil's gold production, exceeding 100 t/year in 1988 and 1989. However, garimpeiro alluvial production decreased 'rapidly in the 1990s, to about 10 t/year by 1999. Company production increased about tenfold from about 4 t/year in 1982 to 40 t in 1992. Production from 1992 to the present remained relatively stable, even though several mines were closed or were in the process of closing and no new major mines were put into production during that period. Based on their production history from 1982-1999, 17 gold mines are ranked as major (> 20 t) and minor (3-8 t) mines. From 1982-1999, deposits hosted in Archean rocks produced 66% of the gold in Brazil, whereas deposits in Paleoproterozoic and Neoproterozoic rocks accounted for 19% and 15%, respectively. Deposits in metamorphosed sedimentary rocks, especially carbonate-rich rocks and carbonate iron-formation, yielded the great bulk of the gold. Deposits in igneous rocks were of much less importance. The Archean and Paleoproterozoic terranes of Brazil largely lack base-metal-rich volcanogenic massive sulfide deposits, porphyry deposits, and polymetallic veins and sedimentary exhalative deposits. An exception to this is in the Caraja??s Mineral Province.

Mineralium Deposita↗

USGS2025

Environmental persistence and toxicity of weathered wildland fire retardants to rainbow trout

Long-term fire retardants are employed to combat and control wildfires by altering the way fuels burn, and they continue to decrease fire intensity after water in the retardant solution has evaporated. After application, fire retardants may persist on dry stream beds or in riparian habitats before precipitation events flush the retardant into intermittent streams. We exposed juvenile (30–60 days post swim-up) rainbow trout ( Oncorhynchus mykiss ) to fire retardants weathered for 7–56 days on different substrates (duff, gravel, high organic content soil, and low organic content soil) under static conditions for 96 h to evaluate the potential toxicity of two current-use long-term fire-retardant (LC95A-R and MVP-Fx) products. Trout mortality was greater in LC95A-R treatments compared to MVP-Fx due to higher concentrations of LC95A-R in the applied product than MVP-Fx at the same application rate. Underlying substrate affected fire-retardant toxicity, with 31% higher average mortality for products applied to duff and gravel compared to soil. Differences in mortality across substrates and products after weathering may be attributed to differences in the mix ratio of applied product and interactions of product chemistries with underlying substrate. These interactions resulted in elevated ionic concentrations of the overlying water in duff and gravel treatments. Trout mortality decreased 15% for products weathered 56 days compared to 7 days. Our results suggest that long-term fire retardants may persist in the environment and that underlying substrate may alter the toxicity of these products upon entrance into an intermittent stream.

Archives of Environmental Contamination and Toxico↗

USGS2013

Factors influencing the movement biology of migrant songbirds confronted with an ecological barrier

Whether or not a migratory songbird embarks on a long-distance flight across an ecological barrier is likely a response to a number of endogenous and exogenous factors. During autumn 2008 and 2009, we used automated radio tracking to investigate how energetic condition, age, and weather influenced the departure timing and direction of Swainson’s thrushes ( Catharus ustulatus ) during migratory stopover along the northern coast of the Gulf of Mexico. Most birds left within 1 h after sunset on the evening following capture. Those birds that departed later on the first night or remained longer than 1 day were lean. Birds that carried fat loads sufficient to cross the Gulf of Mexico generally departed in a seasonally appropriate southerly direction, whereas lean birds nearly always flew inland in a northerly direction. We did not detect an effect of age or weather on departures. The decision by lean birds to reorient movement inland may reflect the suitability of the coastal stopover site for deposition of fuel stores and the motivation to seek food among more extensive forested habitat away from the barrier.

Behavioral Ecology and Sociobiology↗