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At least 1,225 records · Page 68Linked to original sources
USGS1982

Evaluation of AMOEBA: a spectral-spatial classification method

Muitispectral remotely sensed images have been treated as arbitrary multivariate spectral data for purposes of clustering and classifying. However, the spatial properties of image data can also be exploited. AMOEBA is a clustering and classification method that is based on a spatially derived model for image data. In an evaluation test, Landsat data were classified with both AMOEBA and a widely used spectral classifier. The test showed that irrigated crop types can be classified as accurately with the AMOEBA method as with the generally used spectral method ISOCLS; the AMOEBA method, however, requires less computer time.

Journal of Applied Photographic Engineering↗
USGS2015

Factors affecting the reproductive success of American Oystercatchers Haematopus palliatus on the outer banks of North Carolina

We used an information-theoretic approach to assess the factors affecting the reproductive success of American Oystercatchers Haematopus palliatus on the Outer Banks of North Carolina. We evaluated survival with respect to nesting island, year, time of season, brood age, distance to tide (m), presence of off-road vehicles and proximity of foraging habitat. The daily nest survival (mean 0.981, standard error [SE] 0.002) was affected by year and island, and declined over the nesting season. Mammals were responsible for 54% of identified nest failures. Daily brood survival (mean 0.981, SE 0.002) varied by island and increased non-linearly with age, with highest mortality in the seven days after hatching. Model results indicate direct access to foraging sites has a positive effect on brood survival, whereas presence of off-road vehicles has a negative effect. We studied chick behavior and survival using radio telemetry and direct observation and found that vehicles caused mortality and affected behavior and resource use by oystercatcher chicks. We identified the source of mortality for 37 radio-tagged chicks. Six (16%) were killed by vehicles, 21 (57%) by predators, and 10 (27%) by exposure and starvation. From 1995 to 2008, 25 additional oystercatcher chicks were found dead, 13 (52%) killed by vehicles. Chicks on beaches closed to vehicles used beach and intertidal zones more frequently than chicks on beaches open to vehicles. Chick predators included Great Horned Owls Bubo virginianus, Fish Crows Corvus ossifragus, cats Felis catus, mink Mustela vison, raccoons Procyon lotor, and ghost crabs Ocypode albicans. The factors affecting reproductive success differed between the incubation and chick-rearing stages. Management actions that influence chick survival will have a larger effect on total productivity than actions affecting nest survival.

North Carolina↗
USGS2007

The blind men and the elephant: Concerns about the use of juvenile proportion data

Juvenile proportion data in shorebirds are being used with increasing frequency to estimate recruitment and even breeding success. Although this area of investigation holds great promise, flaws in current study designs preclude great confidence in the broad-scale inferences being drawn. We present data from our own investigations on juvenile proportions in Bar-tailed Godwits Limosa lapponica in Alaska to illustrate the significance of some of these problems. We then explore issues of study design, specifically bias, precision, untested assumptions and the use of correlations for interpreting juvenile proportion data. The issue of bias is particularly important, because inferences about shorebird productivity are being expanded to geographic areas well beyond what the data legitimately allow. Until studies of juvenile proportions are more rigorously designed and implemented, we suggest that many of the inferences about shorebird productivity based on such data are premature and may lead to management decisions that are detrimental to the conservation of shorebirds.

Stilt - The journal for the East Asian-Australasia↗
USGS1991

Agricultural research to improve water quality

ime courses for ingest~on, retention and release via feces of microbial food was investigated using 2 b~valves w~th d~fferent feeding strategies, Potamocorbula amurensis and Macoma balthica. The results showed 2 pathways for the uptake of food material in these clams. The first is represented by an initlal label pulse in the feces. The second pathway operates over longer time periods. Inert "Cr-labeled beads were used to determine time frames for these pathways. The first pathway, involving extracellular digestion and intestinal uptake, is relatively inefficient In the digestion of bacter~al cells by P amurensis but more efficient in M. balthica. The second pathway, involving intracellular digestion withln the digestive gland of both clams, was highly efficient in absorb~ng bacterial carbon, and was responsible for most chromium uptake. Differences in the overall retention of microbial "Cr and I4C relate not to gut-passage times but to the processing and release strategies of the food material by these 2 clams.

Journal of Soil and Water Conservation↗
USGS1983

Conodonts of the western Paleozoic and Triassic belt, Klamath Mountains, California and Oregon

Conodonts were extracted from 32 samples of limestone and 5 samples of chert obtained from the Western Paleozoic and Triassic belt of the Klamath Mountains province. Triassic conodonts were found in 17 samples, and late Paleozoic conodonts in 7 samples. Conodonts of the remaining 13 samples cannot be dated more closely than early or middle Paleozoic through Triassic. The late Paleozoic conodonts are restricted to the North Fork and Hayfork terranes. The Hayfork terrane also contains Early, Middle, and Late Triassic conodonts; mostly Neogondolella. Conodonts from samples of the Rattlesnake Creek terrane and the northern undivided part of the belt are all Late Triassic and are generally Epigondolella. The conodont data support the concept that many of the limestone bodies are olistoliths or tectonic blocks in melange. Color alteration of the conodonts indicates that the rocks of the Western Paleozoic and Triassic belt have been heated to temperatures between 300 degrees and 500 degrees C during regional tectonism.

California, Oregon↗
USGS2018

Unusual foraging observations associated with seabird die-offs in Alaska

We report the first documentation of off-water foraging by the Fork-tailed Storm-Petrel Oceanodroma furcata and Short-tailed Shearwater Ardenna tenuirostris, a behavior not previously documented in any member of the families Hydrobatidae or Procellariidae. Over a two-week period in September 2016, we regularly observed individuals of these species over land on an extensive intertidal zone on the Bristol Bay coast of the Alaska Peninsula. We documented irregular feeding behaviors by storm-petrels, including pattering over shallow water and sand, digging into sand to uncover food items, and feeding on beach-cast fish. We revisited the site in August 2017 and did not observe storm-petrels, but we observed four shearwaters feeding on a beach-cast fish. The aberrant feeding behaviors, paucity of stomach contents and emaciated body condition of salvaged and collected birds, together with patterns between bird occurrence and wind speed and direction, indicate to us that these birds were blown to shore while weakened by food stress or compromised health. We further suggest that these aberrant feeding behaviors may be related to massive seabird die-offs that occurred in this region during 2014–2016, die-offs in which Forktailed Storm-Petrels have heretofore not been reported as a species affected by this phenomenon.

Alaska↗
USGS1950

"Lockhartia" cushmani Applin and Jordan and notes on two previously described foraminifera from tertiary rocks in Florida

This paper discusses changes made in the names of three foraminiferal species originally described by the writers, with particular emphasis on "Lockhartia" cushmani Applin and Jordan. The internal characters of this form are fully described and compared with the diagnostic characteristics of the genus Lockhartia Davies and with the geno-lectotype of Rotalia , R. trochidiformis Lamarck, as given by Davies (1932). Comparisons are also made with Lockhartia bermudezi Cole. A plate of illustrations demonstrates the features described. In addition. Elphidium leonensis Applin and Jordan is briefly discussed and the generic placement of Miscellanea nassauensis Applin and Jordan is mentioned.

Florida↗
USGS1991

Fractal hierarchies of magma transport in Hawaii and critical self- organization of tremor

A hierarchical model of magma transport in Hawaii is developed from the seismic records of deep (30-60 km) and intermediate-depth (5-15 km) harmonic tremor between January 1, 1962, and December 31, 1983. A tremor model of magma transport is developed from mass balances of percolation that are proportional to tremor durations. It gives reasonable magma fractions and residence times for a vertical drift velocity of 4 km yr -1 and yields patterns of intermittency that are in accord with singularity analyses of the 22-year time series record. It is suggested that spatiotemporal universality extends from small to large scales in Hawaiian and other magmatic systems. The apparent universal scaling of frequencies may be more than 15 decades in time (1 s to about 60 m.y.) and 10 decades in length (0.1 mm to 10 3 km). -from Authors

Hawaii↗
USGS1983

Opening of the Red Sea: Constraints from a palaeomagnetic study of the As Sarat volcanic field, south‐western Saudi Arabia

Four stratigraphic sections through alkali basalt flows of Oligocene to Miocene age (29‐24 Ma) in the As Sarat volcanic field, south‐western Saudi Arabia, were sampled for palaeomagnetic study. After systematic alternating‐field demagnetization, 42 magnetically acceptable flows (139 samples) yield a mean direction of magnetization of =355.3°, =15.2° (α=4.3°), which defines a palaeomagnetic pole at 78.8°N, 247.8°E. Of these acceptable flows, 24 are normally, and 18 reversely, magnetized. Part of one section was apparently erupted during the early phases of a polarity reversal of the Earth's field. The mean direction derived from the 24 normally magnetized flows is significantly different (after inverting 180°) from that derived from the 18 reversed flows, supporting the hypothesis of a displaced dipole source for the Earth's field in late Oligocene to early Miocene time. A comparison of the results from As Sarat with palaeomagnetic results from upper Tertiary rocks in Africa indicates that the Red Sea has opened 12° (estimated ±8° at the 95 per cent confidence level). These results indicate that most of the counter‐clockwise rotation of Arabia relative to Africa occurred since the eruption of the As Sarat volcanics, in disagreement with proposed models for main‐stage Red Sea spreading from late Eocene to early Oligocene time. The palaeomagnetic results also indicate that the Arabian Peninsula was more equatorial in late Oligocene to early Miocene time than it is now, by an amount compatible with the opening of the Gulf of Aden

As Sarat volcanic field↗
USGS1977

Mercury, arsenic, lead, cadmium, and selenium residues in fish, 1971-73--National Pesticide Monitoring Program.

As part of the National Pesticide Monitoring Program, the Fish and Wildlife Service, U.S. Department of Interior, analyzed selected fish samples from 100 monitoring stations for residues of mercury, arsenic, lead, cadmium, or selenium in 1971-73. At most stations, detectable residues of all metals were present in more than 95 percent of the composite samples. Fishes with mercury residues exceeding 0.5 mg/kg wet weight in the whole fish were mainly predators. Fishes with residues of arsenic, lead, cadmium, and selenium exceeding 0.5 mg/kg included predatory and nonpredatory species. The number of composite samples in which residues of these elements exceeded 0.5 mg/kg decreased from 1971 to 1973, whereas the percentage of samples with detectable residues increased slightly. Only selected samples were analyzed in 1973; therefore, these figures should be used only cautiously as trend data. Species of fish collected varied considerably between geographic regions but were similar from year to year within each region.

Pesticides Monitoring Journal↗
USGS2018

Direct substitution of fishmeal with bioprocessed soybean meal in brown trout diets

This 121-day experiment evaluated the rearing performance of juvenile brown trout ( Salmo trutta ; initial weight 56.1±1.6 g, length 167.2±1.4 mm, mean ±SE) fed one of four isonitrogenous and isocaloric diets (46% protein, 16% lipid). Fishmeal, the primary protein source for the reference diet, was compared to diets where bioprocessed soybean meal directly replaced approximately 60, 80, or 100% of the dietary fishmeal. At the end of the experiment there were no significant differences in gain, percent gain, food fed, feed conversion ratio, nor specific growth rate among any of the dietary treatments. Gains for the 0, 60, 80, and 100% treatments were 304.6 ± 40.3 g, 215.4±82.6 g, 199.0±39.4 g, and 218.1±37.0 g, respectively. There were also no significant differences observed in intestinal morphology, relative fin lengths, viscerosomatic index, hepatosomatic index, or splenosomatic index among the dietary treatments. Based on these results, bioprocessed soybean meal may be able to replace 100% of the dietary fishmeal in juvenile brown trout diets without any deleterious effects.

Journal of Fisheries and Aquaculture Development↗
USGS2020

Effect of environmental factors on the movement of Rainbow Trout in the Deerfield Reservoir System

Spawning movements and the factors affecting those movements are often of interest to fisheries managers and biologists. The objective of this study was to examine the influence of environmental factors on the movements of an adfluvial Rainbow Trout Oncorhynchus mykiss population in the Black Hills, South Dakota. Three unique strains of hatchery-reared Rainbow Trout and resident Rainbow Trout were implanted with passive integrated transponder (PIT) tags and movements between Deerfield Reservoir and the Castle Creek tributary system were monitored from August, 2010-July, 2011. Initial adfluvial movements of Rainbow Trout were detected using a stationary PIT tag reader deployed near the mouth of Castle Creek. Multiple linear regressions were used to model the relationship between PIT tagged Rainbow Trout movement and water temperature, photoperiod, and discharge. Using Akaike’s information criterion (AIC) to compare models, discharge was the top supported model explaining variation in Rainbow Trout movement. Additionally, models containing temperature and photoperiod were also supported. Supported models only explained moderate levels of variation (<23%) in Rainbow Trout movement. Understanding how environmental variables affect the movement patterns of this unique population is essential in determining the proper management strategy for the Deerfield Reservoir system.

South Dakota↗
USGS1976

The Placer River Silt — An intertidal deposit caused by the 1964 Alaska earthquake

At the head of Turnagain Arm near Anchorage, the major lasting geologic consequence of the Alaska earthquake of 1964 was deposition of the Placer River Silt, an intertidal deposit covering an area of more than 18 km 2 and containing more than 20X10 6 m 3 of sediment. This formation, which was derived from erosion of intertidal bars in Turnagain Arm, averages 1.5 m thick seaward of the Seward Highway and 0.9 m thick landward. Its distribution is controlled both, by the arrangement of the major streams that enter tidewater and by manmade features such as the highway and railroad embankments. The Placer River Silt is still being deposited. The contemporary lowland sedimentation system of the Portage area includes a number of depositional settings: (1) In the Placer River Silt upper tidal flats, levees, and channelway fans, (2) elsewhere in the intertidal zone tidal stream channels, lower tidal flats, and saltwater marsh, and (3) in the supratidal zone gravel levees, freshwater marsh, bogs, and lakes. Since 1964, the critical environmental results of the earthquake-caused deposition have been abandonment of the settlement of Portage, formation of an unsightly blanket of silt, destruction of natural plant communities, localized erosion, and creation of quicksand hazards.

Alaska↗
USGS2012

Keanakākoʻi Tephra produced by 300 years of explosive eruptions following collapse of Kīlauea's caldera in about 1500 CE

The Keanakākoʻi Tephra at Kīlauea Volcano has previously been interpreted by some as the product of a caldera-forming eruption in 1790 CE. Our study, however, finds stratigraphic and 14 C evidence that the tephra instead results from numerous eruptions throughout a 300-year period between about 1500 and 1800. The stratigraphic evidence includes: (1) as many as six pure lithic ash beds interleaved in sand dunes made of earlier Keanakākoʻi vitric ash, (2) three lava flows from Kīlauea and Mauna Loa interbedded with the tephra, (3) buried syneruptive cultural structures, (4) numerous intraformational water-cut gullies, and (5) abundant organic layers rich in charcoal within the tephra section. Interpretation of 97 new accelerator mass spectrometry (AMS) 14 C ages and 4 previous conventional ages suggests that explosive eruptions began in 1470–1510 CE, and that explosive activity continued episodically until the early 1800s, probably with two periods of quiescence lasting several decades. Kīlauea's caldera, rather than forming in 1790, predates the first eruption of the Keanakākoʻi and collapsed in 1470–1510, immediately following, and perhaps causing, the end of the 60-year-long, 4–6 km 3 ʻAilāʻau eruption from the east side of Kīlauea's summit area. The caldera was several hundred meters deep when the Keanakākoʻi began erupting, consistent with oral tradition, and probably had a volume of 4–6 km3. The caldera formed by collapse, but no eruption of lava coincided with its formation. A large volume of magma may have quickly drained from the summit reservoir and intruded into the east rift zone, perhaps in response to a major south-flank slip event, leading to summit collapse. Alternatively, magma may have slowly drained from the reservoir during the prolonged ʻAilāʻau eruption, causing episodic collapses before the final, largest downdrop took place. Two prolonged periods of episodic explosive eruptions are known at Kīlauea, the Keanakākoʻi and the Uwēkahuna Tephra (Fiske et al., 2009), and both occurred when a deep caldera existed, probably with a floor at or below the water table, and external water could readily interact with the magmatic system. The next period of intense explosive activity will probably have to await the drastic deepening of the present caldera (or Halemaʻumaʻu Crater) or the formation of a new caldera.

Hawai'i↗
USGS2006

Constraints on the mechanism of long-term, steady subsidence at Medicine Lake volcano, northern California, from GPS, leveling, and InSAR

Leveling surveys across Medicine Lake volcano (MLV) have documented subsidence that is centered on the summit caldera and decays symmetrically on the flanks of the edifice. Possible mechanisms for this deformation include fluid withdrawal from a subsurface reservoir, cooling/crystallization of subsurface magma, loading by the volcano and dense intrusions, and crustal thinning due to tectonic extension (Dzurisin et al., 1991 [Dzurisin, D., Donnelly-Nolan, J.M., Evans, J.R., Walter, S.R., 1991. Crustal subsidence, seismicity, and structure near Medicine Lake Volcano, California. Journal of Geophysical Research 96, 16, 319-16, 333.]; Dzurisin et al., 2002 [Dzurisin, D., Poland, M.P., Bürgmann, R., 2002. Steady subsidence of Medicine Lake Volcano, Northern California, revealed by repeated leveling surveys. Journal of Geophysical Research 107, 2372, doi:10.1029/2001JB000893.]). InSAR data that approximate vertical displacements are similar to the leveling results; however, vertical deformation data alone are not sufficient to distinguish between source mechanisms. Horizontal displacements from GPS were collected in the Mt. Shasta/MLV region in 1996, 1999, 2000, 2003, and 2004. These results suggest that the region is part of the western Oregon block that is rotating about an Euler pole in eastern Oregon. With this rotation removed, most sites in the network have negligible velocities except for those near MLV caldera. There, measured horizontal velocities are less than predicted from ∼10 km deep point and dislocation sources of volume loss based on the leveling data; therefore volumetric losses simulated by these sources are probably not causing the observed subsidence at MLV. This result demonstrates that elastic models of subsurface volume change can provide misleading results where additional geophysical and geological constraints are unavailable, or if only vertical deformation is known. The deformation source must be capable of causing broad vertical deformation with comparatively smaller horizontal displacements. Thermoelastic contraction of a column of hot rock beneath the volcano cannot reproduce the observed ratio of vertical to horizontal surface displacements. Models that determine deformation due to loading by the volcano and dense intrusions can be made to fit the pattern of vertical displacements by assuming a weak upper crust beneath MLV, though the subsidence rates due to surface loading must be lower than the observed displacements. Tectonic extension is almost certainly occurring based on fault orientations and focal mechanisms, but does not appear to be a major contributor to the observed deformation. We favor a model that includes a combination of sources, including extension and loading of a hot weak crust with thermal contraction of a cooling mass of rock beneath MLV, which are processes that are probably occurring at MLV. Future microgravity surveys and the planned deployment of an array of continuous GPS stations as part of a Plate Boundary Observatory volcano cluster will help to refine this model.

California↗
USGS1986

Determination of the components of stormflow using water chemistry and environmental isotopes, Mattole River basin, California

The chemical and isotopic composition of rainfall and stream water was monitored during a storm in the Mattole River basin of northwestern California. About 250 mm of rain fell during 6 days (∼80% within a 42 h period) in late January, 1972, following 24 days of little or no precipitation. River discharge near Petrolia increased from 22 m 3 s −1 to a maximum of 1300 m 3 s −1 while chloride and silica concentrations decreased only from 3.2 to 2.1 and 11.5 to 8.6 mgl −1 , respectively. Meanwhile, the isotopic composition of the river changed from δD = -42%, δ 18 O = -6.8% and 40 tritium units (T.U.) to extreme values at highest flow of δD = -35%, δ 18 O = -5.9% and 25 T.U. in response to volume-weighted rainfall averaging δD = -19.5%, δ 18 O = -3.1% and 18 T.U. Despite much rainfall of a composition quite different from that of the prestorm river water, “buffering” processes in the watershed greatly restricted changes in the chemical and isotopic content of the river during storm runoff. Because of the physical and hydrologic characteristics of the watershed, major contributions of groundwater to stormflow are very unlikely. The large increase in dissolved chemical load observed at maximum river discharge required that extensive interaction with, and presumably penetration of, soils occurred within a few hours time. Such a large increase in chemical load also required subsurface stormflow throughout a high proportion of the watershed. Chemical and isotopic stabilization of stormflow is believed to be due mainly to displacement of prestorm soil water, with some effects on river chemistry due to rapid rain-soil interactions. The isotopic and chemical composition of prestorm soil moisture cannot readily be predicted a priori because of possible variability in rainfall composition, evaporation, and exchange with atmospheric moisture, nor can it be assumed that baseflow has a predictable relation to the chemical or isotopic composition of water displaced from soils during storms. Therefore, it seems inappropriate to draw conclusions as to the relative proportions of groundwater and rainfall in runoff from a particular storm based only on the average compositions of rainfall, stormflow, and prestorm river water, as has been done in most previous isotope hydrograph studies. Given the great variation in hydrology, topography, soil characteristics, rainfall intensity and quantity, etc. from place to place, the relative amount of overland flow, subsurface flow from the unsaturated zone and of groundwater in stormflow can vary greatly in time and space.

California↗