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At least 793 records · Page 44Linked to original sources
USGS1968

Hornblendes from granitic rocks of the central Sierra Nevada batholith, California

Twenty samples of hornblendes from rocks of 14 plutonic units in the central Sierra Nevada and Inyo Mountains, California, have been studied in detail. Optical, density, single-crystal and powder X-ray diffraction, and major and minor element chemical data are reported.The compositions of the hornblendes show only limited correlation with the chemistry of the rocks in which they occurred. Hornblendes from granitic rocks of the eastern Sierra Nevada and Inyo Mountains have a wide range of tetrahedral aluminum content which is often as low as three-quarters of an atom per formula unit, whereas hornblendes from younger granitic rocks elsewhere in the Sierra Nevada batholith contain more than one atom of tetrahedral aluminum per formula unit. Because an increase of aluminum in tetrahedral co-ordination is considered indicative of higher temperatures of crystallization, the observed differences in the hornblendes suggest that older plutonic rocks of the batholith may have been metamorphosed regionally or may have been affected by widespread hydrothermal action prior to consolidation of later granitic rocks.

California↗
USGS1978

Yersinia ruckeri sp. nov., the redmouth (RM) bacterium

Cultures of the redmouth (RM) bacterium, one of the etiological agents of redmouth disease in rainbow trout ( Salmo gairdneri ) and certain other fishes, were characterized by means of their biochemical reactions, by deoxyribonucleic acid (DNA) hybridization, and by determination of guanine-plus-cytosine (G+C) ratios in DNA. The DNA relatedness studies confirmed the fact that the RM bacteria are members of the family Enterobacteriaceae and that they comprise a single species that is not closely related to any other species of Enterobacteriaceae. They are about 30% related to species of both Serratia and Yersinia. A comparison of the biochemical reactions of RM bacteria and serratiae indicated that there are many differences between these organisms and that biochemically the RM bacteria are most closely related to yersiniae. The G+C ratios of RM bacteria were approximated to be between 47.5 and 48.5%. These values are similar to those of yersiniae but markedly different from those of serratiae. On the basis of their biochemical reactions and their G+C ratios, the RM bacteria are considered to be a new species of Yersinia , for which the name Yersinia ruckeri is proposed. Strain 2396-61 (= ATCC 29473) is designated the type strain of the species.

International Journal of Systematic Bacteriology↗
USGS1994

Methanolobus taylorii sp nov, a new methylotropic, estuarine methanogen

Previously published phylogenetic studies of 16S rRNA showed that methylotrophic, slightly halophilic, methanogenic strain GS-16 T (T = type strain) represents a new species of bacterium. We propose the name Methanolobus taylorii for this species; strain GS-16 is the type strain.

International Journal of Systematic Bacteriology↗
USGS2005

Geobacter bemidjiensis sp. nov. and Geobacter psychrophilus sp. nov., two novel Fe(III)-reducing subsurface isolates

Fe(III)-reducing isolates were recovered from two aquifers in which Fe(III) reduction is known to be important. Strain Bem T was enriched from subsurface sediments collected in Bemidji, MN, USA, near a site where Fe(III) reduction is important in aromatic hydrocarbon degradation. Strains P11, P35 T and P39 were isolated from the groundwater of an aquifer in Plymouth, MA, USA, in which Fe(III) reduction is important because of long-term inputs of acetate as a highway de-icing agent to the subsurface. All four isolates were Gram-negative, slightly curved rods that grew best in freshwater media. Strains P11, P35 T and P39 exhibited motility via means of monotrichous flagella. Analysis of the 16S rRNA and nifD genes indicated that all four strains are δ -proteobacteria and members of the Geobacter cluster of the Geobacteraceae . Differences in phenotypic and phylogenetic characteristics indicated that the four isolates represent two novel species within the genus Geobacter . All of the isolates coupled the oxidation of acetate to the reduction of Fe(III) [iron(III) citrate, amorphous iron(III) oxide, iron(III) pyrophosphate and iron(III) nitrilotriacetate]. All four strains utilized ethanol, lactate, malate, pyruvate and succinate as electron donors and malate and fumarate as electron acceptors. Strain Bem T grew fastest at 30 °C, whereas strains P11, P35 T and P39 grew equally well at 17, 22 and 30 °C. In addition, strains P11, P35 T and P39 were capable of growth at 4 °C. The names Geobacter bemidjiensis sp. nov. (type strain Bem T =ATCC BAA-1014 T =DSM 16622 T =JCM 12645 T ) and Geobacter psychrophilus sp. nov. (strains P11, P35 T and P39; type strain P35 T =ATCC BAA-1013 T =DSM 16674 T =JCM 12644 T ) are proposed.

International Journal of Systematic and Evolutiona↗
USGS2000

Methods for accurate estimation of net discharge in a tidal channel

Accurate estimates of net residual discharge in tidally affected rivers and estuaries are possible because of recently developed ultrasonic discharge measurement techniques. Previous discharge estimates using conventional mechanical current meters and methods based on stage/discharge relations or water slope measurements often yielded errors that were as great as or greater than the computed residual discharge. Ultrasonic measurement methods consist of: 1) the use of ultrasonic instruments for the measurement of a representative 'index' velocity used for in situ estimation of mean water velocity and 2) the use of the acoustic Doppler current discharge measurement system to calibrate the index velocity measurement data. Methods used to calibrate (rate) the index velocity to the channel velocity measured using the Acoustic Doppler Current Profiler are the most critical factors affecting the accuracy of net discharge estimation. The index velocity first must be related to mean channel velocity and then used to calculate instantaneous channel discharge. Finally, discharge is low-pass filtered to remove the effects of the tides. An ultrasonic velocity meter discharge-measurement site in a tidally affected region of the Sacramento-San Joaquin Rivers was used to study the accuracy of the index velocity calibration procedure. Calibration data consisting of ultrasonic velocity meter index velocity and concurrent acoustic Doppler discharge measurement data were collected during three time periods. Two sets of data were collected during a spring tide (monthly maximum tidal current) and one of data collected during a neap tide (monthly minimum tidal current). The relative magnitude of instrumental errors, acoustic Doppler discharge measurement errors, and calibration errors were evaluated. Calibration error was found to be the most significant source of error in estimating net discharge. Using a comprehensive calibration method, net discharge estimates developed from the three sets of calibration data differed by less than an average of 4 cubic meters per second, or less than 0.5% of a typical peak tidal discharge rate of 750 cubic meters per second.

IEEE Journal of Oceanic Engineering↗
USGS2016

Off-road vehicles affect nesting behaviour and reproductive success of American Oystercatchers Haematopus palliatus

As human populations and associated development increase, interactions between humans and wildlife are occurring with greater frequency. The effects of these interactions, particularly on species whose populations are declining, are of great interest to ecologists, conservationists, land managers and natural resource policy-makers. The American Oystercatcher Haematopus palliatus , a species of conservation concern in the USA, nests on coastal beaches subject to various forms of anthropogenic disturbance, including aircraft overflights, off-road vehicles and pedestrians. This study assessed the effects of these human disturbances on the incubation behaviour and reproductive success of nesting American Oystercatchers at Cape Lookout National Seashore, on the Atlantic coast of the USA. We expanded on-going monitoring of Oystercatchers at Cape Lookout National Seashore by supplementing periodic visual observations with continuous 24-h video and audio recording at nests. Aircraft overflights were not associated with changes in Oystercatcher incubation behaviour, and we found no evidence that aircraft overflights influenced Oystercatcher reproductive success. However, Oystercatchers were on their nests significantly less often during off-road vehicle and pedestrian events than they were during control periods before the events, and an increase in the number of off-road vehicles passing a nest during incubation was consistently associated with significant reductions in daily nest survival (6% decrease in daily nest survival for a one-vehicle increase in the average number of vehicles passing a nest each day; odds ratio = 0.94; 95% confidence interval (CI) 0.90, 0.98) and hatching success (12% decrease in hatching success for a one-vehicle increase in the average number of vehicles passing a nest each day; odds ratio = 0.88; 95% CI 0.76, 0.97). Management of vehicles and pedestrians in areas of Oystercatcher breeding is important for the conservation of American Oystercatchers.

International Journal of Avian Science↗
USGS2011

Lithosphere-asthenosphere interaction beneath the western United States from the joint inversion of body-wave traveltimes and surface-wave phase velocities

The relation between the complex geological history of the western margin of the North American plate and the processes in the mantle is still not fully documented and understood. Several pre-USArray local seismic studies showed how the characteristics of key geological features such as the Colorado Plateau and the Yellowstone Snake River Plains are linked to their deep mantle structure. Recent body-wave models based on the deployment of the high density, large aperture USArray have provided far more details on the mantle structure while surface-wave tomography (ballistic waves and noise correlations) informs us on the shallow structure. Here we combine constraints from these two data sets to image and study the link between the geology of the western United States, the shallow structure of the Earth and the convective processes in mantle. Our multiphase DNA10-S model provides new constraints on the extent of the Archean lithosphere imaged as a large, deeply rooted fast body that encompasses the stable Great Plains and a large portion of the Northern and Central Rocky Mountains. Widespread slow anomalies are found in the lower crust and upper mantle, suggesting that low-density rocks isostatically sustain part of the high topography of the western United States. The Yellowstone anomaly is imaged as a large slow body rising from the lower mantle, intruding the overlying lithosphere and controlling locally the seismicity and the topography. The large E-W extent of the USArray used in this study allows imaging the 'slab graveyard', a sequence of Farallon fragments aligned with the currently subducting Juan de Fuca Slab, north of the Mendocino Triple Junction. The lithospheric root of the Colorado Plateau has apparently been weakened and partly removed through dripping. The distribution of the slower regions around the Colorado Plateau and other rigid blocks follows closely the trend of Cenozoic volcanic fields and ancient lithospheric sutures, suggesting that the later exert a control on the locus of magmato-tectonic activity today. The DNA velocity models are available for download and slicing at http://dna.berkeley.edu. ?? 2011 The Authors Geophysical Journal International ?? 2011 RAS.

Geophysical Journal International↗
USGS2006

Effects of temperature on biochemical reactions and drug resistance of virulent and avirulent Aeromonas salmonicida

Incubation temperatures of 11°, 18° and 28° did not substantially affect biochemical reactions of either virulent or avirulent forms of Aeromonas salmonicida subspecies salmonicida. The only change observed, amygdalin fermentation, was positive at 11° and 18° but negative at 28°C. Several isolates utilized sucrose, a characteristic not normally recognized for A. salmonicida subspecies salmonicida. Antimicrobial susceptibility screening indicated resistance to novobiocin increased at the higher incubation temperatures. Standardized drug sensitivity testing procedures and precise zone diameter interpretive standards for bacterial fish pathogens are needed.

Journal of Fish Diseases↗
USGS2006

Tolerance of lake trout, Salvelinus namaycush (Walbaum), sac fry to dissolved gas supersaturation

The tolerance of sac fry of lake trout, Salvelinus namaycush (Walbaum), to the acute effects of gas supersaturation, from hatching to swim-up, was tested using six gas levels, ranging from ΔP 8 to 148. Although many fish were moribund by the time the yolk was nearly absorbed, mortality during the 40-day study was negligible; survival to swim-up was 96–99%, including 99% survival at ΔP 148. Of fish examined at ΔP 42, 40% showed bubble formation around the rim of the eye. Signs of trauma were greatest at ΔP 119 and 148, and included intestinal bubbles, a distended abdomen, and bubbles around the eye, in the mouth and in jaw tissues.

Journal of Fish Diseases↗
USGS2007

Quantifying fluid and bed dynamics for characterizing benthic physical habitat in large rivers

Sturgeon use benthic habitats in and adjacent to main channels where environmental conditions can include bedload sediment transport and high near-bed flow velocities. Bed velocity measurements obtained with acoustic Doppler instruments provide a means to assess the concentration and velocity of sediment moving near the streambed, and are thus indicative of the bedload sediment transport rate, the near-bed flow velocity, and the stability of the substrate. Acoustic assessments of benthic conditions in the Missouri River were conducted at scales ranging from the stream reach to individual bedforms. Reach-scale results show that spatially-averaged bed velocities in excess of 0.5 m s-1 frequently occur in the navigation channel. At the local scale, bed velocities are highest near bedform crests, and lowest in the troughs. Low-velocity zones can persist in areas with extremely high mean bed velocities. Use of these low-velocity zones may allow sturgeon to make use of portions of the channel where the average conditions near the bed are severe. To obtain bed velocity measurements of the highest possible quality, it is necessary to extract bottom-track and GPS velocity information from the raw ADCP data files on a ping-by-ping basis. However, bed velocity measured from a point can also be estimated using a simplified method that is more easily implemented in the context of routine monitoring. The method requires only the transect distance and direction data displayed in standard ADCP data-logging software. Bed velocity estimates obtained using this method are usually within 5-10% of estimates obtained from ping-by-ping processing. ?? 2007 Blackwell Verlag.

Journal of Applied Ichthyology↗
USGS2007

Anemia and mechanism of erythrocyte destruction in ducks with acute Leucocytozoon infections

In the anemia which accompanies infection by Leucocytozoon simondi in Pekin ducks there was a far greater loss of erythrocytes than could be accounted for as a result of direct physical rupture by the parasite. Erythrocyte loss began at the same time the 1st parasites appeared in the blood and was severest just prior to maximum parasitemia. Blood replacement and parasite loss occurred simultaneously. Examination of the spleen and bone marrow revealed that erythrophagocytosis was not the cause of anemia as reported for infections of Plasmodium, Babesia and Anaplasma . An anti-erythrocyte (A-E) factor was found in the serum of acutely infected ducks which agglutinated and hemolyzed normal untreated duck erythrocytes as well as infected cells. This A-E factor appeared when the 1st red cell loss was detected and reached its maximum titer just prior to the greatest red cell loss. Titers of the A-E factor were determined using normal uninfected erythrocytes at temperatures between 4 and 42 C. Cells agglutinated below 25 C and hemolyzed at 37 and 42 C. These results indicated that the A-E factor could be responsible for loss of cells other than those which were infected and could thus produce an excess loss of red cells.

Journal of Protozoology↗
USGS2007

Passive immunization of pigeons against trichomoniasis

Nonimmune homing pigeons Columba livia were infected with the Jones' Barn strain of Trichomonas gallinae and subsequently transfused with plasma from acute or chronically infected pigeons harboring one of 3 different strains of T. gallinae. The transfusions were either a single 2 ml dose given one day after inoculation or three 1 ml doses given 0, 5, and 10 days after inoculation. Plasma from pigeons harboring any of the 3 strains was capable of passively immunizing nonimmune birds. All birds which were immunized with plasma from infected pigeons survived until killed at the end of the test period and no visceral lesions were found on necropsy but trichomonads were present in the oropharynx. All controls (untreated or transfused with normal plasma) died of visceral trichomoniasis. Immune plasma produced some lysis of trichomonads in vitro, and inhibition of motility and vacuolization occurred in some of the non-lysed organisms. The overall lytic activity in vitro affected less than 10% of the suspended trichomonads.

Journal of Protozoology↗
USGS2008

Predators of Dusky Canada Goose goslings and the effect of transmitters on gosling survival

The population of Dusky Canada Geese (Branta canadensis occidentalis) has been in long-term decline, likely due to reduced breeding productivity. To identify causes of mortality, we monitored goslings marked with radio transmitters on the western Copper River Delta, Alaska, from 1997 to 1999. Almost all gosling mortality (96%; 81 of 84) was due to predation, with mink (Mustela vison) and Bald Eagles (Haliaeetus leucocephalus) the most important predators. Bald Eagles are also major nest predators and, thus, appear to play a key role in limiting the breeding productivity of Dusky Canada Geese. Daily survival rate for goslings to 28 d of age was lower (0.011; 95% CI 0.002-0.024) for those with transmitters than for those without, but did not differ for older goslings (29-45 d). Although finer resolution in the timing of the transmitter effect within the first 28 d was not possible, we found that, by limiting our sample to goslings that survived until after 2-3 d posthatching, support for a transmitter effect was much reduced. Younger, smaller birds are inherently more vulnerable than older birds to transmitter effects. In addition, the process of radio-marking may have delayed the departure of goslings from nests and increased their risk of mortality shortly after hatching. Although radio transmitters may often be the only practical means for determining causes of mortality for young waterfowl, we suggest caution in using transmitters because of their potential negative effects, particularly during the first few days after hatching. ?? 2008 Association of Field Ornithologists.

Journal of Field Ornithology↗
USGS2007

Contributions of rainfall to constituent loads in storm runoff from urban catchments

Rainfall is a significant source of some constituents, particularly nitrogen species, in storm runoff from urban catchments. Median contributions of rainfall to storm runoff loads of 12 constituents from 31 urban catchments, representing eight geographic locations within the United States, ranged from 2 percent for suspended solids to 74 percent for total nitrite plus nitrate nitrogen. The median contribution of total nitrogen in rainfall to runoff loads was 41 percent. Median contributions of total-recoverable lead in rainfall to runoff loads varied by as much as an order of magnitude between catchments in the same geographic location. This indicates that average estimates of rainfall contributions to constituent loading in storm runoff may not be suitable in studies requiring accurate constituent mass-balance computations.

Journal of the American Water Resources Associatio↗
USGS2007

Altered streamflow and sediment entrainment in the Gunnison Gorge

The Gunnison River in the Gunnison Gorge is a canyon river where upstream dams regulate mainstem discharge but do not affect debris-flow sediment supply from tributaries entering below the reservoirs. Regulation since 1966 has altered flood frequency, streambed mobility, and fluvial geomorphology creating potential resource-management issues. The duration of moderate streamflows between 32.3 and 85.0 m3/s has increased threefold since 1966. This, along with flood-peak attenuation, has facilitated fine-sediment deposition and vegetation encroachment on stream banks. The Shields equation and on-site channel geometry and bed-material measurements were used to assess changes in sediment entrainment in four alluvial reaches. Sand and fine gravel are transported through riffle/pool reaches at most discharges, but the cobbles and boulders composing the streambed in many reaches now are infrequently entrained. Periodic debris flows add coarse sediment to rapids and can increase pool elevation and the streambed area affected by backwater and fine-sediment accumulation. Debris-flow supplied boulders accumulate on fans and in rapids and constrict the channel until reworked by larger floods. The response to streamflow-regime changes in the Gunnison Gorge could serve as an analog for alluvial reaches in other regulated canyon rivers.

Journal of the American Water Resources Associatio↗
USGS2007

Regression models for estimating herbicide concentrations in U.S. streams from watershed characteristics

Regression models were developed for estimating stream concentrations of the herbicides alachlor, atrazine, cyanazine, metolachlor, and trifluralin from use-intensity data and watershed characteristics. Concentrations were determined from samples collected from 45 streams throughout the United States during 1993 to 1995 as part of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA). Separate regression models were developed for each of six percentiles (10th, 25th, 50th, 75th, 90th, 95th) of the annual distribution of stream concentrations and for the annual time-weighted mean concentration. Estimates for the individual percentiles can be combined to provide an estimate of the annual distribution of concentrations for a given stream. Agricultural use of the herbicide in the watershed was a significant predictor in nearly all of the models. Several hydrologic and soil parameters also were useful in explaining the variability in concentrations of herbicides among the streams. Most of the regression models developed for estimation of concentration percentiles and annual mean concentrations accounted for 50 percent to 90 percent of the variability among streams. Predicted concentrations were nearly always within an order of magnitude of the measured concentrations for the model-development streams, and predicted concentration distributions reasonably matched the actual distributions in most cases. Results from application of the models to streams not included in the model development data set are encouraging, but further validation of the regression approach described in this paper is needed.

Journal of the American Water Resources Associatio↗