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At least 343 records · Page 19Linked to original sources
USGS2016

Hanging out at the airport: Unusual upside-down perching behavior by Eurasian Jackdaws (Corvus monedula) in a human-dominated environment

Animals occupying human-dominated environments show the capacity for behavioral flexibility. Corvids are among the most intelligent synanthropic bird species. During a layover at Schipol Airport in Amsterdam, Netherlands, I photographically documented Eurasian Jackdaws ( Corvus monedula ) perching upside down from a building cornice. In contrast to other reports of hanging birds, these jackdaws did not forage or play while upside down and appeared to use the perching spot to observe their surroundings. Although Corvids and Psittacines are known to hang upside down, especially in captive situations, such behaviors are rarely documented in the wild, and never before in association with human-built structures.

Wilson Journal of Ornithology↗
USGS2004

Delineation of a collapse feature in a noisy environment using a multichannel surface wave technique

A collapse developed at Calvert Cliffs Nuclear Power Plant, Maryland, in early 2001. The location of the collapse was over a groundwater drainage system pipe buried at an elevation of +0??9 m (reference is to Chesapeake Bay level). The cause of the collapse was a subsurface drain pipe that collapsed because of saltwater corrosion of the corrugated metal pipe. The inflow/outflow of sea water and groundwater flow caused soil to be removed from the area where the pipe collapsed. To prevent damage to nearby structures, the collapse was quickly filled with uncompacted sand and gravel (???36000 kg). However, the plant had an immediate need to determine whether more underground voids existed. A high-frequency multichannel surface-wave survey technique was conducted to define the zone affected by the collapse. Although the surface-wave survey at Calvert Cliffs Nuclear Power Plant was conducted at a noise level 50-100 times higher than the normal environment for a shallow seismic survey, the shear (S)-wave velocity field calculated from surface-wave data delineated a possible zone affected by the collapse. The S-wave velocity field showed chimney-shaped low-velocity anomalies that were directly related to the collapse. Based on S-wave velocity field maps, a potential zone affected by the collapse was tentatively defined.

Geotechnique↗
USGS1997

Soil, plant, and structural considerations for surface barriers in arid environments: Application of results from studies in the Mojave Desert near Beatty, Nevada

The suitability of a waste-burial site depends on hydrologic processes that can affect the near-surface water balance. In addition, the loss of burial trench integrity by erosion and subsidence of trench covers may increase the likelihood of infiltration and percolation, thereby reducing the effectiveness of the site in isolating waste. Although the main components of the water balance may be defined, direct measurements can be difficult, and actual data for specific locations are seldom available. A prevalent assumption is that little or no precipitation will percolate to buried wastes at an arid site. Thick unsaturated zones, which are common to arid regions, are thought to slow water movement and minimize the risk of waste migration to the underlying water table. Thus, reliance is commonly placed on the natural system to isolate contaminants at waste-burial sites in the arid West. Few data are available to test assumptions about the natural soil-water flow systems at arid sites, and even less is known about how the natural processes are altered by construction of a waste-burial facility. The lack of data is the result of technical complexity of hydraulic characterization of the dry, stony soils, and insufficient field studies that account for the extreme temporal and spatial variations in precipitation, soils, and plants in arid regions. In 1976, the U.S. Geological Survey (USGS) began a long-term study at a waste site in the Mojave Desert. This paper summarizes the findings of ongoing investigations done under natural-site and waste-burial conditions, and discusses how this information may be applied to the design of surface barriers for waste sites in arid environments. The waste-burial site is in one of the most arid parts of the United States and is about 40 km northeast of Death Valley, near Beatty, Nev. (Figure 1). Precipitation averaged 108 mm/yr during 1981-1992. The water table is 85-115 m below land surface (Fischer, 1992). Sediments are largely alluvial and fluvial deposits (Nichols, 1987). Vegetation is sparse; creosote bush is the dominant species. The waste facility has been used for burial of low-level radioactive waste (1962-1992) and hazardous chemical waste (1970 to present). Burial-trench construction includes excavation of native soil, emplacement of waste, and backfilling with previously stockpiled soil. Only the most recently closed hazardous-waste trench (1991) incorporates a plastic liner in the cover. The surfaces of completed burial trenches and perimeter areas are kept free of vegetation.

Nevada↗
USGS2022

Active‐source interferometry in marine and terrestrial environments: Importance of directionality and stationary phase

We utilize active‐source seismic interferometry with dense seismic arrays both offshore and onland to explore the utility of this method to create virtual sources and reveal body‐wave reflections in these two different environments. We first utilize data from an ocean‐bottom cable (OBC) array in the Gulf of Mexico with equal numbers of sources (160 airgun shots) and receivers (160 ocean‐bottom four‐component sensors). We next use data from a geophone array across the Bighorn Mountains of Wyoming with many receivers (1300 vertical‐component geophones) but a small number of sources (14 borehole active‐source shots). We find that the OBC virtual source results, which produce strong reflections from sub‐seafloor structures, are far superior to the onland results which lack usable reflections, and we explore reasons for these differences through a set of selective stacking approaches. We present techniques to account for the direction the seismic waves travel (directionality) and stationary phase and show that improvements can be made when incorporating these corrections. Although interferometric methods are based on assumptions of large numbers of widely distributed actual sources, we find that selective exclusion of potentially problematic source–receiver pairs can yield improved results. These geometric adjustments to active‐source interferometry methods have utility for dense‐nodal‐array surveys that are now common in academic studies, but that often suffer from sparse source geometry.

Bulletin of the Seismological Society of America↗
USGS2007

Iteroparity in the variable environment of the salamander Ambystoma tigrinum

Simultaneous estimation of survival, reproduction, and movement is essential to understanding how species maximize lifetime reproduction in environments that vary across space and time. We conducted a four-year, capture–recapture study of three populations of eastern tiger salamanders ( Ambystoma tigrinum tigrinum ) and used multistate mark–recapture statistical methods to estimate the manner in which movement, survival, and breeding probabilities vary under different environmental conditions across years and among populations and habitats. We inferred how individuals may mitigate risks of mortality and reproductive failure by deferring breeding or by moving among populations. Movement probabilities among populations were extremely low despite high spatiotemporal variation in reproductive success and survival, suggesting possible costs to movements among breeding ponds. Breeding probabilities varied between wet and dry years and according to whether or not breeding was attempted in the previous year. Estimates of survival in the nonbreeding, forest habitat varied among populations but were consistent across time. Survival in breeding ponds was generally high in years with average or high precipitation, except for males in an especially ephemeral pond. A drought year incurred severe survival costs in all ponds to animals that attempted breeding. Female salamanders appear to defer these episodic survival costs of breeding by choosing not to breed in years when the risk of adult mortality is high. Using stochastic simulations of survival and breeding under historical climate conditions, we found that an interaction between breeding probabilities and mortality limits the probability of multiple breeding attempts differently between the sexes and among populations.

Virginia↗
USGS2003

Productivity and breeding habitat of loggerhead shrikes in a southwestern urban environment

Declines in loggerhead shrike (Lanius ludovicianus) populations have been associated in part with habitat loss and degradation, including that resulting from urbanization. We monitored the productivity and examined nesting habitat of loggerhead shrikes nesting in an urban environment in Tucson, Arizona. We located 22 breeding pairs in 1997 and 26 breeding pairs in 1998, with a 72% breeding area reoccupancy between years. Mean fledgling numbers were 2.28/ nesting attempt and 3.11/successful nest. Although some pairs initially failed and renested, 91% and 73% of shrike pairs successfully fledged young in 1997 and 1998, respectively. Mayfield estimates of nesting success were 78% in 1997 and 65% in 1998. Nest sites were characterized by more trees >3 m in height, taller nest trees than those randomly available, and a greater proportion of bare ground surface than at random sites. Shrike breeding territories had lower proportions of residential and commercial development and greater proportions of open areas with low-growing vegetation than randomly available. Some shrikes nested in school playgrounds, residential front yards, and parking lots, if adjacent open space was available.

Southwestern Naturalist↗
USGS2003

The behavior of U- and Th-series nuclides in the estuarine environment

Rivers carry the products of continental weathering, and continuously supply the oceans with a broad range of chemical constituents. This erosional signature is, however, uniquely moderated by biogeochemical processing within estuaries. Estuaries are commonly described as complex filters at land-sea margins, where significant transformations can occur due to strong physico-chemical gradients. These changes differ for different classes of elements, and can vary widely depending on the geographic location. U- and Th-series nuclides include a range of elements with vastly different characteristics and behaviors within such environments, and the isotopic systematics provide methods for investigating the transport of these nuclides and other analog species across estuaries and into the coastal ocean.

Reviews in Mineralogy and Geochemistry↗
USGS1990

Fine-grained rutile in the Gulf of Maine: Diagenetic origin, source rocks, and sedimentary environment of deposition

The Gulf of Maine, an embayment of the New England margin, is floored by shallow, glacially scoured basins that are partly filled with late Pleistocene and Holocene silt and clay containing 0.7 to 1.0 wt percent TiO 2 , chiefly in the form of silt-size rutile. Eleven basins in the gulf are estimated to contain 479 X 10 6 metric tons of TiO 2 (to a depth of 10 m) in the U.S. exclusive economic zone and 168 X 10 6 in Canada, based on analyses of surface sediment and of cores 10 to 20 m long. The U.S. annually consumes approximately 1 X 10 6 metric tons of TiO 2 , of which 73 percent is imported. The inferred amount of fine-grained TiO 2 in the basins is large, and we interpret it to be predominantly rutile; but no attempt has been made yet to mine and beneficiate the fine-grained ore.Sedimentary rocks of Nova Scotia, New Brunswick, and northern Maine contain fine-grained rutile crystals and have been the major source of the fine-grained sediment in the Gulf of Maine basins during and after the Wisconsinan glaciation. We conclude that much of the rutile in the Gulf of Maine mud formed diagenetically in poorly cemented Carboniferous and Triassic coarse-grained sedimentary rocks of Nova Scotia and New Brunswick after the dissolution of titanium-rich detrital minerals (ilmenite, ilmenomagnetite). Another major source of rutile is the generally finer grained Paleozoic sedimentary rocks of northern Maine (and possibly northwestern New Brunswick) which contain recycled diagenetic rutile that most likely originated in sandstones. Additional Wisconsinan sources of fine-grained, diagenetic TiO 2 probably include sedimentary rocks of inferred Triassic age that underlie the Gulf of Maine.The diagenesis of rutlie in coarse sedimentary rocks (especially arkose and graywacke) followed by erosion, segregation, and deposition (and including recycling of fine-grained rutile from shales) can serve as a model for predicting and prospecting for unconsolidated deposits of fine-grained TiO 2 .Gulf of Maine mud is comparable in TiO 2 content to typical shale. A determination of whether the fine-grained TiO 2 in shales primarily occurs as detrital titanium minerals from metamorphic and igneous sources or as recycled, diagenetic titanium oxides from sedimentary sources may assist in interpreting shale provenance and environment of deposition.

Economic Geology↗
USGS1997

Environment of ore deposition in the creede mining district, San Juan Mountains, Colorado: Part V. Epithermal mineralization from fluid mixing in the OH vein

Detailed fluid inclusion studies on coarse-grained sphalerite from the OH vein, Creede, Colorado, have shown that the abrupt color changes between growth zones correspond to abrupt changes in the nature of the ore fluids. Within each growth zone, however, the composition of the fluids remained constant. The base of a distinctive orange-brown growth zone marks a sharp increase in both temperature and salinity relative to the preceding yellow-white zone. The orange-brown growth zone can be correlated along much of the vein and is believed to represent a time-stratigraphic interval. Along the vein, temperatures and salinities of fluid inclusions within this interval show a systematic decrease from about 285??C and 11.5 wt percent NaCl equiv near the base of the vein to about 250??C and 8 wt percent NaCl equiv, respectively, near the top of the vein. The iron concentration of this sphalerite growth zone shows a similar pattern, decreasing from about 2.8 to 1.2 mole percent FeS. When plotted on an enthalpy-salinity diagram, the fluid inclusion data define a spatial trend indicating the progressive mixing of deeply circulating hydrothermal brines with overlying, dilute ground waters. The hydrothermal brines entered the OH vein from below at a temperature, salinity, and density of approximately 285??C, 11.5 wt percent NaCl equiv, and 860 kg/m3, respectively, whereas the overlying ground waters appear to have been preheated to roughly 150??C and had an assumed salinity of 0 wt percent and a density of 920 kg/m3. The greater density of the heated ground water promoted mixing with the hydrothermal brine within the open fractures, causing sphalerite deposition. Although there were also episodes of boiling during vein mineralization, boiling appears unimportant for this sphalerite. Isotopic evidence and geochemical modeling studies also indicate that mixing was the depositional mechanism for sphalerite. An important aspect of the mixing hydrology of the Creede system involves an aquitard overlying the OH vein. This low permeability zone restricted the flow of ground water into the vein from above and forced the upwelling hydrothermal fluids to flow laterally along the vein. The mixing environment thus occurred along the interface between a deeply circulating hydrothermal convection cell and a topographically driven shallow ground-water system.

Economic Geology↗
USGS2000

Bedrock knobs, San Francisco Bay: Do navigation hazards outweigh other environment problems?

Three bedrock knobs (Arch, Harding, and Shag rocks) rise above the unconsolidated sediment of central San Francisco Bay to a water depth of less than -12 m (<-39.4 ft MLLW). These rocks are within the westbound vessel traffic area, and the northernmost, Harding Rock, is approximately 300 m (984 ft) from the two-way deep water traffic lane. The rocks pose a hazard to deep-draft vessels. Large ships with drafts deeper than -17 m (-55.8 ft) cross central San Francisco Bay bound for and returning from major port cities of the Bay estuary. Acoustic profiling data show that bedrock extends at a gentle to moderate slope away from the knobs. These data also show that two of the knobs, Harding and Shag, may be part of a bedrock ridge that extends to Alcatraz Island and perhaps southeast to Blossom Rock. The tops of these rocks should be lowered to a depth of -17 m (-55.8 ft), with a total volume of as much as 245,000 m 3 (320,460 yd 3 ), at an estimated cost of nearly 27 million dollars, to eliminate the possibility that a tanker would strike one and rupture. A resulting large oil spill would likely cost many times more than the 10 million dollars needed to clean up a small 1996 spill. If the rocks were removed, local habitat for striped bass and other game fish would be altered, with potential negative impact on sport fishing. Currently, public officials are studying the benefits to the Bay environment of lowering the rock knobs.

California↗
USGS2006

Microbial transformations of arsenic in the environment: From soda lakes to aquifers

Arsenic is a highly toxic element that supports a surprising range of biogeochemical transformations. The biochemical basis of these microbial interactions is described, with an emphasis on energy-yielding redox biotransformations that cycle between the As5+ and As3+ oxidation states. The subsequent impact of As3+-oxidising and As 5+-reducing prokaryotes on the chemistry of selected environments is also described, focusing on soda lakes with naturally high concentrations of the metalloid and on Southeast Asian aquifer sediments, where the microbial reduction of sorbed As5+ and subsequent mobilisation of As 3+ into water abstracted for drinking and irrigation threaten the lives of millions.

Elements↗
USGS2012

Impact of wildfire and slope aspect on soil temperature in a mountainous environment

Soil temperature changes after landscape disturbance impact hydrology, ecology, and geomorphology. This study used field measurements to examine wildfire and aspect effects on soil temperatures. Combustion of the litter and duff layers on north-facing slopes removed pre-fire aspect-driven soil temperature controls. Wildfire is one of the most significant disturbances in mountainous landscapes and can affect soil temperature, which can in turn impact ecologic and geomorphologic processes. This study measured the temperature in near-surface soil (i.e., top 30 cm) during the first summer after a wildfire. In mountainous environments, aspect can also affect soil temperature, so north- vs. south-facing aspects were compared using a fully factorial experimental design to explore the effects of both wildfire and aspect on soil temperature. The data showed major wildfire impacts on soil temperatures on north-facing aspects (unburned ∼4–5°C cooler, on average) but little impact on south-facing aspects. Differences in soil temperatures between north-facing and south-facing unburned aspects (north ∼5°C cooler, on average) were also observed. The data led to the conclusion that, for this field site during the summer period, the forest canopy and litter and duff layers on north-facing slopes (when unburned) substantially decreased mean soil temperatures and temperature variability. The sparse trees on south-facing slopes caused little to no difference in soil temperatures following wildfire in south-facing soils for unburned compared with burned conditions. The results indicate that wildfire can reduce or even remove aspect impacts on soil temperature by combusting the forest canopy and litter and duff layers, which then homogenizes soil temperatures across the landscape.

Vadose Zone Journal↗
USGS2010

Habitat selection of Rocky Mountain elk in a nonforested environment

Recent expansions by Rocky Mountain elk (Cervus elaphus) into nonforested habitats across the Intermountain West have required managers to reconsider the traditional paradigms of forage and cover as they relate to managing elk and their habitats. We examined seasonal habitat selection patterns of a hunted elk population in a nonforested high-desert region of southwestern Wyoming, USA. We used 35,246 global positioning system locations collected from 33 adult female elk to model probability of use as a function of 6 habitat variables: slope, aspect, elevation, habitat diversity, distance to shrub cover, and distance to road. We developed resource selection probability functions for individual elk, and then we averaged the coefficients to estimate population-level models for summer and winter periods. We used the population-level models to generate predictive maps by assigning pixels across the study area to 1 of 4 use categories (i.e., high, medium-high, medium-low, or low), based on quartiles of the predictions. Model coefficients and predictive maps indicated that elk selected for summer habitats characterized by higher elevations in areas of high vegetative diversity, close to shrub cover, northerly aspects, moderate slopes, and away from roads. Winter habitat selection patterns were similar, except elk shifted to areas with lower elevations and southerly aspects. We validated predictive maps by using 528 locations collected from an independent sample of radiomarked elk (n = 55) and calculating the proportion of locations that occurred in each of the 4 use categories. Together, the high- and medium-high use categories of the summer and winter predictive maps contained 92% and 74% of summer and winter elk locations, respectively. Our population-level models and associated predictive maps were successful in predicting winter and summer habitat use by elk in a nonforested environment. In the absence of forest cover, elk seemed to rely on a combination of shrubs, topography, and low human disturbance to meet their thermal and hiding cover requirements.

Journal of Wildlife Management↗
USGS1990

Hurricane impacts on the coastal environment

In terms of insured losses, Hurricane Andrew is the most severe catastrophe in the Nation's history. Prior to the arrival of Andrew, the U.S. Geological Survey (USGS), in cooperation with the Louisiana Geological Survey (LGS), acquired an extensive body of information and data on the behavior and long-term erosion of Louisiana barrier islands. As a result, we have a clear understanding of pre-storm conditions in this area; Andrew provided an opportunity to learn in detail the impact of a very large storm on Louisiana coastal environment.

Fact Sheet↗
USGS1975

Norfolk and environs: A land use perspective

The Norfolk-Portsmouth Standard Metropolitan Statistical Area (SMSA) in southeastern Virginia was the site of intensive testing of a number of land resources assessment methods, built around the availability of remotely sensed data from the Earth Resources Technology Satellite (ERTS-I), later renamed LANDSAT I. The Norfolk tests were part of a larger experiment known as the Central Atlantic Regional Ecological Test Site (CARETS), designed to test the extent to which LANDSAT and associated high-altitude aircraft data could be used as cost-effective inputs to a regional land use information system. The Norfolk SMSA contains a variety of land uses typical of the urbanized eastern seaboard, along with typical associated problems: rapid urbanization; heavy recreational, commercial, and residential demands on fragile beaches and coastal marsh environments; industrial, transportation, and governmental land and water uses impacting on residential and agricultural areas; drainage and land stability difficulties affecting construction and other uses; and increasing difficulties in maintaining satisfactory air and water quality.

Delaware;Maryl;New Jersey;North Carolina;Pennsylva↗
USGS1975

Norfolk and environs: A land use perspective

The Norfolk-Portsmouth Standard Metropolitan Statistical Area (SMSA) in southeastern Virginia was the site of intensive testing of a number of land resources assessment methods, built around the availability of remotely sensed data from the Earth Resources Technology Satellite (ERTS-I), later renamed LANDSAT I. The Norfolk tests were part of a larger experiment known as the Central Atlantic Regional Ecological Test Site (CARETS), designed to test the extent to which LANDSAT and associated high-altitude aircraft data could be used as cost-effective inputs to a regional land use information system. The Norfolk SMSA contains a variety of land uses typical of the urbanized eastern seaboard, along with typical associated problems: rapid urbanization; heavy recreational, commercial, and residential demands on fragile beaches and coastal marsh environments; industrial, transportation, and governmental land and water uses impacting on residential and agricultural areas; drainage and land stability difficulties affecting construction and other uses; and increasing difficulties in maintaining satisfactory air and water quality.

Delaware;Maryl;New Jersey;North Carolina;Pennsylva↗
USGS2000

Composition and depositional environment of concretionary strata of early Cenomanian (early Late Cretaceous) age, Johnson County, Wyoming

Unusual, concretion-bearing mudrocks of early Late Cretaceous age, which were deposited in an early Cenomanian epeiric sea, have been recognized at outcrops in eastern Wyoming and in adjoining areas of Montana, South Dakota, Nebraska, and Colorado. In Johnson County, Wyo., on the western flank of the Powder River Basin, these strata are in the lower part of the Belle Fourche Member of the Frontier Formation. At a core hole in south-central Johnson County, they are informally named Unit 2. These strata are about 34 m (110 ft) thick and consist mainly of medium- to dark-gray, noncalcareous, silty shale and clayey or sandy siltstone; and light-gray to grayish-red bentonite. The shale and siltstone are either bioturbated or interlaminated; the laminae are discontinuous, parallel, and even or wavy. Several ichnogenera of deposit feeders are common in the unit but filter feeders are sparse. The unit also contains marine and continental palynomorphs and, near the top, a few arenaceous foraminifers. No invertebrate macrofossils have been found in these rocks. Unit 2 conformably overlies lower Cenomanian shale in the lowermost Belle Fourche Member, informally named Unit 3, and is conformably overlain by lower and middle Cenomanian shale, siltstone, and sandstone within the member, which are informally named Unit 1. The mineral and chemical composition of the three Cenomanian units is comparable and similar to that of shale and siltstone in the Upper Cretaceous Pierre Shale, except that these units contain more SiO2 and less CaO, carbonate carbon, and manganese. Silica is generally more abundant and CaO is generally less abundant in river water than in seawater. The composition of Unit 2 contrasts significantly with that of the underlying and overlying units. Unit 2 contains no pyrite and dolomite and much less sulfur than Units 1 and 3. Sulfate is generally less abundant in river water than in seawater. Unit 2 also includes sideritic and calcitic concretions, whereas Units 1 and 3 contain neither concretions nor siderite and only sparse calcite. Carbon-sulfur-iron chemistry for the concretions suggests that sulfate availability was the limiting factor in pyrite formation and sulfide incorporation in Unit 2. Isotopic compositions of the carbon and oxygen in siderite and calcite from several concretions are variable and suggest cementation during early diagenesis in a variety of microenvironments. The isotopic composition of these carbonate minerals differs from that of Upper Cretaceous marine limestones. When considered in conjunction with the proportions of sulfur, organic carbon, and iron in Unit 2, major-element and micropaleontological data suggest that the composition of the original pore waters and of overlying waters in the late early Cenomanian sea was brackish to fresh. The mudrocks of Units 3 and 2, and a lower part of Unit 1, accumulated on a shelf at low to moderate rates of sedimentation in association with variable but generally weak current action. In Unit 2 and laterally equivalent rocks of the region, the sideritic and calcitic concretions probably indicate the extent of a body of brackish to fresh and oxygen-deficient water. Rates of precipitation in this region during the mid-Cretaceous could have been unusually high and the precipitation probably was seasonal. The organic matter in Unit 2 is humic-rich and would have been derived from continental environments. If the epeiric sea was brackish to fresh in the region of eastern Wyoming and contiguous areas, meteoric runoff from the adjoining lowlands must have been periodically large and the seaway north of the region probably was constricted. Seasonal changes in salinity might have been accompanied by changes in water temperature and oxygen content. The lower part of the Frontier Formation (Units 3, 2, and 1) in Wyoming records an intermittently and easterly prograding shoreline during late early and early middle Cenomanian time. Laterally equivalent strata in Nebraska

Bulletin↗