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Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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At least 91 records · Page 5Linked to original sources
USGS2008

Lesser snow geese and ross's geese form mixed flocks during winter but differ in family maintenance and social status

Smaller species are less likely to maintain families (or other forms of social groups) than larger species and are more likely to be displaced in competition with larger species. We observed mixed-species flocks of geese in southwest Louisiana and compared frequencies of social groups and success in social encounters of Lesser Snow Geese (Chen caerulescens caerulescens; hereafter Snow Geese) with that of the smaller, closely- related Ross's Geese (C. rossii). Less than 7% of adult and <l4% of juvenile Ross's Geese were in families, whereas 10-22% of adult and 12-15% of juvenile Snow Geese were in families. Snow Geese won 70% of interspecific social encounters and had higher odds of success against Ross's Geese than against individuals of their own species. The larger Snow Geese maintain families longer than Ross's Geese, which probably contributes to their dominance over Ross's Geese during winter. Predator vigilance probably is an important benefit of mixed flocking for both species. We suggest the long-standing association with Snow Geese (along with associated subordinate social status) has selected against family maintenance in Ross's Geese.

Wilson Journal of Ornithology↗
USGS2011

Soil physical, chemical, and gas-flux characterization from Picea mariana stands near Erickson Creek, Alaska

Fire is a particularly important control on the carbon (C) balance of the boreal forest, and fire-return intervals and fire severity appear to have increased since the late 1900s in North America. In addition to the immediate release of stored C to the atmosphere through organic-matter combustion, fire also modifies soil conditions, possibly affecting C exchange between terrestrial and atmospheric pools for decades after the burn. The effects of fire on ecosystem C dynamics vary across the landscape, with topographic position and soil drainage functioning as important controls. The data reported here contributed to a larger U.S. Geological Survey (USGS) study, published in the journal Ecosystems by O'Donnell and others (2009). To evaluate the effects of fire and drainage on ecosystem C dynamics, we selected sample sites within the 2003 Erickson Creek fire scar to measure CO 2 fluxes and soil C inventories in burned and unburned (control) sites in both upland and lowland black spruce (Picea mariana) forests. The results of this study suggested that although fire can create soil climate conditions which are more conducive to rapid decomposition, rates of C release from soils may be constrained after fire by changes in moisture and (or) substrate quality that impede rates of decomposition. Here, we report detailed site information, methodology, and data (in spreadsheet files) from that study.

Alaska↗
USGS1974

Regional flow system and ground-water quality in western Ohio

Most relatively deep wells drilled in the carbonate aquifers in western Ohio tap a recognizable regional flow system encompassing all or parts of several major basins. The principal recharge area includes the higher, central part of the region, where much of the terrane is hummocky to hilly glacial moraine. The principal discharge areas are the valleys of the major streams and lowlands along Lake Erie. Ground water moving through this system undergoes a progressive change in chemical quality, from a calcium bicarbonate type in recharge areas to a calcium sulfate type in discharge areas. Changes in selected chemical constituents are orderly and, within the observed parameters, predictable.

Ohio↗
USGS2014

Performance and effects of land cover type on synthetic surface reflectance data and NDVI estimates for assessment and monitoring of semi-arid rangeland

Federal land management agencies provide stewardship over much of the rangelands in the arid andsemi-arid western United States, but they often lack data of the proper spatiotemporal resolution andextent needed to assess range conditions and monitor trends. Recent advances in the blending of com-plementary, remotely sensed data could provide public lands managers with the needed information.We applied the Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM) to five Landsat TMand concurrent Terra MODIS scenes, and used pixel-based regression and difference image analyses toevaluate the quality of synthetic reflectance and NDVI products associated with semi-arid rangeland. Pre-dicted red reflectance data consistently demonstrated higher accuracy, less bias, and stronger correlationwith observed data than did analogous near-infrared (NIR) data. The accuracy of both bands tended todecline as the lag between base and prediction dates increased; however, mean absolute errors (MAE)were typically &le;10%. The quality of area-wide NDVI estimates was less consistent than either spectra lband, although the MAE of estimates predicted using early season base pairs were &le;10% throughout the growing season. Correlation between known and predicted NDVI values and agreement with the 1:1regression line tended to decline as the prediction lag increased. Further analyses of NDVI predictions,based on a 22 June base pair and stratified by land cover/land use (LCLU), revealed accurate estimates through the growing season; however, inter-class performance varied. This work demonstrates the successful application of the STARFM algorithm to semi-arid rangeland; however, we encourage evaluation of STARFM&rsquo;s performance on a per product basis, stratified by LCLU, with attention given to the influence of base pair selection and the impact of the time lag.

Idaho, Utah, Wyoming↗
USGS1992

New look at regional flood-frequency relations for arid lands

A new method is proposed that combines records for several streamflow-gaging stations, as in the station-year approach, and produces regional flood-frequency relations using an iterative regression technique. This technique eliminates the need to extrapolate the flood-frequency relation to the flood probability of interest. The resulting multiparameter regional flood-frequency relation is based on all the available annual peak-flow data. The method was applied to a group of records from 42 gaging stations in Nevada with many years of no flow and with many poorly defined flood-frquency relations. One- and two-parameter models were developed in which much of the variance in peak discharge is explained by drainage area. The log-Pearson type III and Weibull probability distributions were used in the models. Part of the error is directly assessed using randomly selected subsamples of the annual peak discharges. -from Authors

Journal of Hydraulic Engineering↗
USGS2011

Microbial water quality before and after the repair of a failing onsite wastewater treatment system adjacent to coastal waters

Aims: The objective was to assess the impacts of repairing a failing onsite wastewater treatment system (OWTS, i.e., septic system) as related to coastal microbial water quality. Methods and Results: Wastewater, groundwater and surface water were monitored for environmental parameters, faecal indicator bacteria (total coliforms, Escherichia coli, enterococci) and the viral tracer MS2 before and after repairing a failing OWTS. MS2 results using plaque enumeration and quantitative reverse transcriptase polymerase chain reaction (qRT‐PCR) often agreed, but inhibition limited the qRT‐PCR assay sensitivity. Prerepair, MS2 persisted in groundwater and was detected in the nearby creek; postrepair, it was not detected. In groundwater, total coliform concentrations were lower and E. coli was not detected, while enterococci concentrations were similar to prerepair levels. E. coli and enterococci surface water concentrations were elevated both before and after the repair. Conclusions: Repairing the failing OWTS improved groundwater microbial water quality, although persistence of bacteria in surface water suggests that the OWTS was not the singular faecal contributor to adjacent coastal waters. A suite of tracers is needed to fully assess OWTS performance in treating microbial contaminants and related impacts on receiving waters. Molecular methods like qRT‐PCR have potential but require optimization. Significance and Impact of Study: This is the first before and after study of a failing OWTS and provides guidance on selection of microbial tracers and methods.

North Carolina↗
USGS2012

Costs of living for juvenile Chinook salmon ( Oncorhynchus tshawytscha ) in an increasingly warming and invaded world

Rapid environmental change in freshwater ecosystems has created a need to understand the interactive effects of multiple stressors, with temperature and invasive predators identified as key threats to imperiled fish species. We tested the separate and interactive effects of water temperature and predation by non-native smallmouth bass ( Micropterus dolomieu ) on the lethal (mortality) and sublethal (behavior, physiology, and growth) effects for juvenile Chinook salmon ( Oncorhynchus tshawytscha ) in seminatural stream channel experiments. Over 48 h trials, there was no difference in direct predation with warmer temperatures, but significant interactive effects on sublethal responses of juvenile salmon. Warmer temperatures resulted in significantly stronger and more variable antipredator responses (surface shoaling and swimming activity), while physiological indicators (plasma glucose, plasma cortisol) suggested suppression of physiological mechanisms in response to the combined stressors. These patterns corresponded with additive negative growth in predation, temperature, and combined treatments. Our results suggest that chronic increases in temperature may not increase direct predation over short periods, but can result in significant sublethal costs with negative implications for long-term development, disease resistance, and subsequent size-selective mortality of Pacific salmon.

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS2017

Suitability of oyster restoration sites along the Louisiana coast: Examining site and stock × site interaction

Recognition of the global loss of subtidal oyster reefs has led to a rise in reef restoration efforts, including in the Gulf of Mexico. Created reef success depends entirely on selecting a location that supports long-term oyster growth and survival, including the recruitment and survival of on-reef oysters. Significant changes in estuarine salinity through management of freshwater inflows and through changed precipitation patterns may significantly impact the locations of optimal oyster restoration sites. These rapid shifts in conditions necessitate a need to better understand both impacts to on-reef oyster growth and population development, and variation in oyster stock performance. Oyster growth, mortality, condition, and disease prevalence were examined in three different stocks of oysters located in protected cages, as well as oyster recruitment and mortality on experimental reef units in three different locations representing a salinity gradient, along the Louisiana Gulf coast in 2011 and 2012. Over a 2-y period, the high-salinity site had highest oyster growth rate in protected cages but demonstrated the least likelihood for reef development based on on-reef oyster population failure, likely because of predation-related mortality (high recruitment and 100% mortality). In contrast, the midsalinity site with moderate oyster growth and on-reef recruitment and low mortality demonstrated a higher likelihood for reef development. The lowest salinity site exhibited extreme variability in all oyster responses between years because of extreme variation in environmental conditions during the study, indicating a low likelihood of long-term reef development. Whereas limited differences in stock performance between sites were found, the range of site environmental conditions tested was ultimately much lower than expected and may not have provided a wide enough range of conditions. In areas with limited, low recruitment, or rapidly changing environmental conditions, seeding with stocks selected for best growth and survival under expected future environmental conditions could better ensure reef development by using oyster populations best suited to the predicted conditions. With rapidly changing estuarine conditions from anthropogenic activities and climate change, siting of oyster reef restoration incorporating both oyster population dynamics and in situ biotic and abiotic interactions is critical in better directing site selection for reef restoration efforts.

Louisiana↗
USGS1977

Platinum, palladium, and rhodium in volcanic and plutonic rocks from the Gravina-Nutzotin belt, Alaska

The Gravina-Nutzotin belt of Middle (?) Jurassic to middle Cretaceous sedimentary and volcanic rocks in south and southeastern Alaska includes concentrically zoned ultramafic complexes known to contain platinum-group metals. Previous isotopic, petrologic, and geologic studies suggested a close relation in time and space between the volcanic rocks and the ultramafic complexes. Interpretation of 40 analyses for platinum, palladium, and rhodium in volcanic and plutonic rocks of the belt indicates a strong geochemical correlation between the two groups of rocks and is in support of their being cogenetic either from directly connected magma chambers and flows or indirectly by selective concentration processes from similar mantle material.

Alaska↗
USGS2015

Elk habitat suitability map for North Carolina

Although eastern elk (Cervus elaphus canadensis) were extirpated from the eastern United States in the 19th century, they were successfully reintroduced in the North Carolina portion of the Great Smoky Mountains National Park in the early 2000s. The North Carolina Wildlife Resources Commission (NCWRC) is evaluating the prospect of reintroducing the species in other locations in the state to augment recreational opportunities. As a first step in the process, we created a state-wide elk habitat suitability map. We used medium-scale data sets and a two-component approach to iden- tify areas of high biological value for elk and exclude from consideration areas where elk-human conflicts were more likely. Habitats in the state were categorized as 66% unsuitable, 16.7% low, 17% medium, and <1% high suitability for elk. The coastal plain and Piedmont contained the most suitable habitat, but prospective reintroduction sites were largely excluded from consideration due to extensive agricultural activities and pervasiveness of secondary roads. We ranked 31 areas (≥ 500 km 2 ) based on their suitability for reintroduction. The central region of the state contained the top five ranked areas. The Blue Ridge Mountains, where the extant population of elk occurs, was ranked 21st. Our work provides a benchmark for decision makers to evaluate potential consequences and trade-offs associated with the selection of prospective elk reintroduction sites.

North Carolina↗
USGS2010

Implications of stunting on morphology of freshwater fishes

The purpose of this study was to assess morphological differences between stunted and non-stunted white perch Morone americana and green sunfish Lepomis cyanellus. Few female M. americana were captured; thus, morphological differences between adult males and juveniles were assessed for M. americana. Similarly, few immature (juvenile) L. cyanellus were captured for the stunted morphotype; thus, male and female morphological differences were assessed for L. cyanellus. Features of the head tended to be relatively larger in stunted fish of both species, whereas the mid-body tended to be relatively larger in non-stunted M. americana, but not in non-stunted L. cyanellus. Adult and juvenile morphology overlapped considerably in non-stunted M. americana, but there was a clear distinction between adult and juvenile morphology of stunted M. americana. There was little sexual dimorphism in shape in stunted L. cyanellus, whereas sexual dimorphism was evident in non-stunted L. cyanellus. It appears that selective forces imposed by predation and food limitation may contribute to morphological diversification between stunted and non-stunted fishes. ?? 2010 The Authors. Journal compilation ?? 2010 The Fisheries Society of the British Isles.

Journal of Fish Biology↗
USGS1964

Sedimentology: general introduction and definitions : fluvial sediment and channel morphology

Sedimentology, the study of sedimentary rocks and the processes by which they are formed, includes and is related to a large number of phenomena. Sedimentology includes the five fundamental processes defined by the term sediaentation --weathering, erosion, transportation, deposition and diagenesis. Sedimentology shares with geomorphology the study of the surface features of the earth. Sedimentology also shares with hydrology the study of river.--channels. River channels are formed in part or in total as a result of flowing water and sediment transport, commonly called the "work of the rivers." This survey of published literature was made to aid in arriving at definitions which would be acceptable to, and representative of, a majority of professional personnel actively engaged in laboratory and field investigations related to the "work of the river." The definitions in this list are intended to explain the terms used in studies of fluvial sediment and channel morphology. No set of definitions can expect universal acceptance, however, i t is hoped that this compilation will be considered a summary and synthesis of present and past usage and that it will serve as a starting point for future usage. Multiple references are cited from textbooks, glossaries and dictionaries, scientific journals and u.s. Government publications. To obtain a mutual understanding and enhance precision, many of the proposed definitions are a composite of those selected from papers or reports covering research studies and field investigations. A draft of this glossary has been reviewed by a group of interested personnel. The results of this review have been carefully considered and the originally-suggested definitions have been revised accordingly, resulting in the present compilation. R. G. Wolff, with the help of Mrs. v. Blatcher, carried out the literature search and compilation of terms and the review results. Paul c. Benedict approved or composed the definitions as presented in this report.

Open-File Report↗
USGS2006

Synthesis of carbon-14 and deuterium labeled N-nitroso-2 (3',7'-dimethyl-2',6'-octadienyl) aminoethanols

Methods of preparation of carbon-14 and deuterium labeled N-nitroso-2(3,7-dimethyl-2,6-octadienyl) aminoethanols are described. The primary synthetic method involved alkylation of ethanolamine or ethylglycine with suitable chlorides and subsequent mild nitrosation. Isomeric 14 C-nitrosamines were also prepared by selective -cleavage of the di-substituted ethanolamine with nitrous acid.

Journal of Labelled compounds and Radiopharmaceuti↗
USGS2011

Genetic and environmental influences on leaf phenology and cold hardiness of native and introduced riparian trees

To explore the roles of plasticity and genetic variation in the response to spatial and temporal climate variation, we established a common garden consisting of paired collections of native and introduced riparian trees sampled along a latitudinal gradient. The garden in Fort Collins, Colorado (latitude 40.6°N), included 681 native plains cottonwood ( Populus deltoides subsp. monilifera ) and introduced saltcedar ( Tamarix ramosissima , T. chinensis and hybrids) collected from 15 sites at 29.2–47.6°N in the central United States. In the common garden both species showed latitudinal variation in fall, but not spring, leaf phenology, suggesting that the latitudinal gradient in fall phenology observed in the field results at least in part from inherited variation in the critical photoperiod, while the latitudinal gradient in spring phenology observed in the field is largely a plastic response to the temperature gradient. Populations from higher latitudes exhibited earlier bud set and leaf senescence. Cold hardiness varied latitudinally in both fall and spring for both species. For cottonwood, cold hardiness began earlier and ended later in northern than in southern populations. For saltcedar northern populations were hardier throughout the cold season than southern populations. Although cottonwood was hardier than saltcedar in midwinter, the reverse was true in late fall and early spring. The latitudinal variation in fall phenology and cold hardiness of saltcedar appears to have developed as a result of multiple introductions of genetically distinct populations, hybridization and natural selection in the 150 years since introduction.

International Journal of Biometeorology↗
USGS2007

An analysis of urban development and its environmental impact on the Tampa Bay watershed

Urbanization has transformed natural landscapes into anthropogenic impervious surfaces. Urban land use has become a major driving force for land cover and land use change in the Tampa Bay watershed of west-central Florida. This study investigates urban land use change and its impact on the watershed. The spatial and temporal changes, as well as the development density of urban land use are determined by analyzing the impervious surface distribution using Landsat satellite imagery. Population distribution and density are extracted from the 2000 census data. Non-point source pollution parameters used for measuring water quality are analyzed for the sub-drainage basins of Hillsborough County. The relationships between 2002 urban land use, population distribution and their environmental influences are explored using regression analysis against various non-point source pollutant loadings in these sub-drainage basins. The results suggest that strong associations existed between most pollutant loadings and the extent of impervious surface within each sub-drainage basin in 2002. Population density also exhibits apparent correlations with loading rates of several pollutants. Spatial variations of selected non-point source pollutant loadings are also assessed.

Journal of Environmental Management↗
USGS2022

New insights into the occurrence and implications of mobile water in gas hydrate systems

Gas hydrate production technologies commonly feature reservoir depressurization. Depressurization occurs when a pressure gradient is established in a well, drawing mobile water from the reservoir and reducing reservoir pressure. As such, the occurrence of mobile water is a necessary condition for effective gas production from gas hydrate reservoirs using common borehole-based methods. However, recent field programs have revealed that mobile water exists widely within the overall gas hydrate reservoir system, including within overlying and underlying units once thought of as virtually impermeable seals. Further, excess free water may also be commonly found in hydrate-free or hydrate-poor permeable strata interbedded within the larger gas hydrate reservoir system. Such internal sources of water are complex to characterize, difficult to explain, potentially highly heterogeneous, and may pose significant challenges to depressurization-based production. This report summarizes the general occurrence of water in gas hydrate systems and select technical implications.

Journal of Energy and Fuels↗
USGS2024

Observations of flocs in an estuary and implications for computation of settling velocity

The settling velocity ( w s ) in estuarine environments can impact whether a region is eroding or accreting sediment on the bed, yet determining this rate can be an indirect process requiring a number of assumptions. Accurate determination of w s is especially needed for numerical models to reproduce observed sediment concentrations at the appropriate timescale. We collected information on suspended sediment flocculation at a channel site (13 m deep) and a shallows site (4 m deep) within South San Francisco Estuary, alongside timeseries of flow, wave statistics, turbulent shear, and bottle samples analyzed for both w s and particle size. Using the measurements of floc size and settling velocity, we performed a sensitivity analysis on the unknown parameters in the general explicit formula for settling velocity. The collected particle size distribution data show that multiple classes of flocs are present; these are characterized as flocculi, microflocs, and macroflocs. We show that w s of flocculi is closest to w s for the full distribution. The determined parameter values lead to near-bed mass-weighted settling velocities (standard deviation) of 1.18 (0.55) and 0.22 (0.15) mm/s at the channel and shallows sites, respectively. Modeling efforts can use this work to help select an appropriate sediment model and parameter values.

California↗