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At least 487 records · Page 27Linked to original sources

USGS2016

Controls on selenium distribution and mobilization in an irrigated shallow groundwater system underlain by Mancos Shale, Uncompahgre River Basin, Colorado, USA

Elevated selenium (Se) concentrations in surface water and groundwater have become a concern in areas of the Western United States due to the deleterious effects of Se on aquatic ecosystems. Elevated Se concentrations are most prevalent in irrigated alluvial valleys underlain by Se-bearing marine shales where Se can be leached from geologic materials into the shallow groundwater and surface water systems. This study presents groundwater chemistry and solid-phase geochemical data from the Uncompahgre River Basin in Western Colorado, an irrigated alluvial landscape underlain by Se-rich Cretaceous marine shale. We analyzed Se species, major and trace elements, and stable nitrogen and oxygen isotopes of nitrate in groundwater and aquifer sediments to examine processes governing selenium release and transport in the shallow groundwater system. Groundwater Se concentrations ranged from below detection limit (< 0.5 μg L − 1 ) to 4070 μg L − 1 , and primarily are controlled by high groundwater nitrate concentrations that maintain oxidizing conditions in the aquifer despite low dissolved oxygen concentrations. High nitrate concentrations in non-irrigated soils and nitrate isotopes indicate nitrate is largely derived from natural sources in the Mancos Shale and alluvial material. Thus, in contrast to areas that receive substantial NO 3 inputs through inorganic fertilizer application, Se mitigation efforts that involve limiting NO 3 application might have little impact on groundwater Se concentrations in the study area. Soluble salts are the primary source of Se to the groundwater system in the study area at-present, but they constitute a small percentage of the total Se content of core material. Sequential extraction results indicate insoluble Se is likely composed of reduced Se in recalcitrant organic matter or discrete selenide phases. Oxidation of reduced Se species that constitute the majority of the Se pool in the study area could be a potential source of Se in the future as soluble salts are progressively depleted.

Colorado↗

USGS2024

The interplay of future solar energy, land cover change, and their projected impacts on natural lands and croplands in the US

Projections for deep decarbonization require large amounts of solar energy, which may compete with other land uses such as agriculture, urbanization, and conservation of natural lands. Existing capacity expansion models do not integrate land use land cover change (LULC) dynamics into projections. We explored the interaction between projected LULC, solar photovoltaic (PV) deployment, and solar impacts on natural lands and croplands by integrating projections of LULC with a model that can project future deployment of solar PV with high spatial resolution for the conterminous United States. We used scenarios of LULC projections from the Intergovernmental Panel on Climate Change Special Report on Emission Scenarios from 2010 to 2050 and two electricity grid scenarios to model future PV deployment and compared those results against a baseline that held 2010 land cover constant through 2050. Though solar PV's overall technical potential was minimally impacted by LULC scenarios, deployed PV varied by −16.5 to 11.6 % in 2050 from the baseline scenario. Total land requirements for projected PV were similar to other studies, but measures of PV impacts on natural systems depended on the underlying land change dynamics occurring in a scenario. The solar PV deployed through 2050 resulted in 1.1 %–2.4 % of croplands and 0.3 %–0.7 % of natural lands being converted to PV. However, the deepest understanding of PV impacts and interactions with land cover emerged when the complete net gains and losses from all land cover change dynamics, including PV, were integrated. For example, one of the four LULC projections allows for high solar development and a net gain in natural lands, even though PV drives a larger percentage of natural land conversion. This paper shows that integrating land cover change dynamics with energy expansion models generates new insights into trade offs between decarbonization, impacts of renewables, and ongoing land cover change.

conterminous United States↗

USGS2018

Mount St. Helens retrospective: Lessons learned since 1980 and remaining challenges

Since awakening from a 123-year repose in 1980, Mount St. Helens has provided an opportunity to study changes in crustal magma storage at an active arc volcano—a process of fundamental importance to eruption forecasting and hazards mitigation. There has been considerable progress, but important questions remain unanswered. Was the 1980 eruption triggered by an injection of magma into an upper crustal reservoir? If so, when? How did magma rise into the edifice without producing detectable seismicity deeper than ∼2.5 km or measurable surface deformation beyond the volcano’s north flank? Would precursory activity have been recognized earlier if current monitoring techniques had been available? Despite substantial improvements in monitoring capability, similar questions remain after the dome-forming eruption of 2004–2008. Did additional magma accumulate in the reservoir between the end of the 1980–1986 eruption and the start of the 2004–2008 eruption? If so, when? What is the significance of a relative lull in seismicity and surface deformation for several years prior to the 2004–2008 eruption onset? How did magma reach the surface without producing seismicity deeper than ∼2 km or measurable deformation more than a few hundred meters from the vent? Has the reservoir been replenished since the eruption ended, and is it now primed for the next eruption? What additional precursors, if any, should be expected? This paper addresses these questions, explores possible answers, and identifies unresolved issues in need of additional study. The 1980–1986 and 2004–2008 eruptions could have resulted from second boiling during crystallization of magma long-resident in an upper crustal reservoir, rather than from injection of fresh magma from below. If reservoir pressurization and magma ascent were slow enough, resulting strain might have been accommodated by viscoelastic deformation, without appreciable seismicity or surface deformation, until rising magma entered a brittle regime within 2–2.5 km of the surface. Given the remarkably gas-poor nature of the 2004–2008 dome lava, future eruptive activity might require a relatively long period of quiescence and reservoir pressurization or a large injection of fresh magma—an event that arguably has not occurred since the Kalama eruptive period (C.E. 1479–1720).

Washington↗

USGS2000

High-resolution seismic reflection to delineate shallow gas in Eastern Kansas

Unique amplitude characteristics of shallow gas sands within Pennsylvanian clastic-carbonate dominated sequences are discernible on high-resolution seismic reflection data in eastern Kansas. Upward grading sequences of sand into shale represent a potential gas reservoir with a low-impedence acoustic contrast at the base of the encasing layer. The gas sand and encasing shale, which define the gas reservoir studied here, are part of an erosional incised valley where about 30 m of carbonates and shale have been replaced by sandstone and shale confined to the incised valley. These consolidated geologic settings would normally possess high impedence gas sand reservoirs as defined by abrupt contacts between the gas sand and encasing shale. Based orr core and borehole logs, the gas sand studied here grades from sand into shale in a fashion analogous to that observed in classic low-impedance environments. Amplitude and phase characteristics of high-resolution seismic data across this approximately 400-m wide gas sand are indicative of a low-impedance reservoir. Shot gathers possess classic amplitude with offsett-dependent characteristics which are manifeted on the stacked section as "bright spots." Dominant Frequencies of around 120 Hz allow detection of several reflectors within the 30+ meters of sand/shale that make up this localized gas-rich incised valley fill. The gradational nature of the trapping mechanism observed in this gas reservoir would make detection with conventional seismic reflection methods unlikely.

The Compass: Earth Science Journal of Sigma Gamma ↗

USGS1997

The loss of hyperosmoregulatory ability in migrating juvenile American shad, Alosa sapidissima

Investigations on juvenile American shad ( Alosa sapidissima ) revealed several physiological changes associated with downstream migration. Plasma chloride decreased 20% in wild juvenile shad during the autumn migration. Migrants had lower condition factor and hematocrit than non-migrant shad captured by beach seining. Gill Na + ,K + -ATPase activity of migrant shad was higher than non-migrant; a 2.5-fold increase was observed in 1993, while a 57% increase was observed in 1994. Similar changes were observed in laboratory studies of shad maintained in fresh water under simulated natural temperature and photoperiod. Plasma chloride dropped 68% and gill Na + ,K + -ATPase activity increased 3-fold over a 3-month period. Decreased plasma chloride was associated with increased mortality. Increases in gill Na + ,K + -ATPase activity decreases in plasma chloride and osmolality, and incidence of mortality were delayed and moderated, but not eliminated, in shad maintained at constant temperature (24°C). Shad did not survive in fresh water past December regardless of temperature regime. In seawater, all shad survived and showed no perturbation of plasma chloride at 24°C or simulated natural temperature (above 4°C). The decline in hyperosmoregulatory ability, as influenced by declining temperatures, may serve as a proximate cue for autumnal migration.

Canadian Journal of Fisheries and Aquatic Sciences↗

USGS2003

The U.S. Geological Survey Land Remote Sensing Program

In 2002, the U. S. Geological Survey (USGS) launched a program to enhance the acquisition, preservation, and use of remotely sensed data for USGS science programs, as well as for those of cooperators and customers. Remotely sensed data are fundamental tools for studying the Earth's land surface, including coastal and near-shore environments. For many decades, the USGS has been a leader in providing remotely sensed data to the national and international communities. Acting on its historical topographic mapping mission, the USGS has archived and distributed aerial photographs of the United States for more than half a century. Since 1972, the USGS has acquired, processed, archived, and distributed Landsat and other satellite and airborne remotely sensed data products to users worldwide. Today, the USGS operates and manages the Landsats 5 and 7 missions and cooperates with the National Aeronautics and Space Administration (NASA) to define and implement future satellite missions that will continue and expand the collection of moderate-resolution remotely sensed data. In addition to being a provider of remotely sensed data, the USGS is a user of these data and related remote sensing technology. These data are used in natural resource evaluations for energy and minerals, coastal environmental surveys, assessments of natural hazards (earthquakes, volcanoes, and landslides), biological surveys and investigations, water resources status and trends analyses and studies, and geographic and cartographic applications, such as wildfire detection and tracking and as a source of information for The National Map. The program furthers these distinct but related roles by leading the USGS activities in providing remotely sensed data while advancing applications of such data for USGS programs and a wider user community.

Fact Sheet↗

USGS1997

Binding of pyrene to aquatic and commercial humic substances: The role of molecular weight and aromaticity

The binding of pyrene to a number of humic substances isolated from various aquatic sources and a commercial humic acid was measured using the solubility enhancement method. The humic materials used in this study were characterized by various spectroscopic and liquid chromatography methods. A strong correlation was observed between the pyrene binding coefficient, K(doc), and the molecular weights, molar absorptivities at 280 nm, and aromaticity of the aquatic humic substances. Binding of pyrene to the commercial humic acid, however, was significantly stronger and did not obey the relationships observed between K(doc) and the chemical properties of the aquatic humic substrates. These results suggest that the molecular weight and the aromatic content of the humic substrates exert influences on the binding of nonpolar and planar aromatic molecules and that the physicochemical properties of both humic materials and organic solutes are important in controlling the speciation of nonpolar organic contaminants in natural waters.

Environmental Science & Technology↗

USGS1999

Fishes of Missouri River, chute, and flood plain habitats: Chapter 4 in Initial biotic survey of Lisbon Bottom, Big Muddy National Fish and Wildlife Refuge

The Lisbon Bottom Unit of the Big Muddy National Fish and Wildlife Refuge (Refuge) is approximately 2,200 acres and is the first complete unit of the Refuge. Primary objectives of the Refuge are to create and restore diverse riverine aquatic habitats and reconnect the Missouri River to its flood plain where feasible. Management seeks to accomplish these objectives by encouraging natural processes of erosion, deposition, and succession to the greatest extent possible. One of the most salient aquatic features of the Lisbon Bottom Unit is a newly created 2-mile-long free-flowing chute, or side channel (Fig. 1). This chute began forming as a levee breech scour hole during the Great Flood of 1993. The chute continued to develop during the 1995 flood and finally cut through to a flowing side channel during the 1996 flood. Extensive erosion and bank sluffing continued during 1997 due to sustained high flows that occurred throughout most of the year. The chute has progressively become wider and deeper with a developing meander pattern and channel bars have begun to form. Lisbon Bottom also contains several seasonal and permanent wetlands and is subject to periodic flooding at high Missouri River stages. Eight studies have been completed or are ongoing to evaluate Missouri River fishes associated with various habitat components of Lisbon Bottom and adjacent Missouri River reaches (Table 1). Several are part of much larger investigations to evaluate fish use of flood-created habitat features, basinwide fish assessment, and endangered or candidate species concerns. At the Lisbon Bottom Unit or in the Missouri River adjacent to the unit 54 fish species were collected (Table 2). Eight of these species have either a protected status under State or Federal laws or biologists consider them to potentially qualify for protected status. The status of the following fish is listed in Table 2: pallid sturgeon x shovelnose sturgeon hybrid, paddlefish, northern pike, sturgeon chub, sicklefin chub, ghost shiner, western silvery minnow, plains minnow, and blue sucker. Equally important to note are fish species that were not collected. The flathead chub, currently listed as State endangered and proposed for Federal listing, were not collected in any of the studies. Common fish species, collected in all seven sampling studies, included gizzard shad, common carp, river carpsucker, and freshwater drum. Paddlefish, skipjack herring, silver carp, white sucker, redfin shiner, western silvery minnow, bullhead minnow, and black bullhead were each collected in only one of the seven studies. Pflieger (1971) developed a guild system for the fishes of Missouri based on distribution patterns and centers of abundance. Fish were assigned to one of four primary faunal groups: Ozark, Big River, Lowland, and Prairie. Two secondary groups (Ozark-prairie and Ozark-lowland) were defined for species equally abundant and distributed in two of the primary areas. Two Ozark-prairie species, shorthead redhorse and white sucker, were collected on or near the Lisbon Bottom Unit. Big River species are found primarily in the Missouri and Mississippi Rivers. The environmental factors controlling fish distribution in these rivers appear to be substrate, current velocity, and turbidity. On or near the Lisbon Bottom Unit 18 Big River species were collected (Table 2). Lowland species are intolerant of siltation and high turbidity. They inhabit standing or slow-moving water with sand, fine gravel, and organic debris substrates. Two Lowland species, bullhead minnow and mosquitofish, were collected in connected scours on the Lisbon Bottom Unit. Prairie species have broader ecological tolerances than the Ozark and Lowland species. They are largely absent in high gradient streams and cool, clear waters. Prairie species make up a significant proportion of Missouri and Mississippi River fishes. Seven Prairie species were collected on or near the Lisbon Bottom Unit (Table 2). The last group, Wide-ranging, was defined as the species more widespread than the other faunal groups with broader environmental tolerances. Most Wide-ranging species occur at least occasionally in all sections of the state. Nineteen Wide-ranging species were collected on or near the Lisbon Bottom Unit (Table 2). Kubisiak (1997) found that isolated scours in the Lower Missouri River were dominated by Wide-ranging species. Connected scours also held Wideranging species but they contained Prairie species and were dominated by Big River species. Faunal group diversity and species richness were compared between isolated (Study l) and connected (Studies 4, 5, 7, and 8) scours of the Lisbon Bottom Unit. Species richness was similar with 22 species collected in isolated scours and an average of 24.8 species collected in connected scours. Isolated scour fish catches were dominated by Wide-ranging fish (59%) with 14% Big River fishes and 14% Prairie fishes. Connected scours had a larger percentage of Big River fish (32%) and fewer Wide-ranging (36%) and Prairie (13%) species than the isolated scours. In the combined studies, Wide-ranging fish dominated the connected scours. A similar comparison was made of fish from chute habitats and the Missouri River. Chute habitats include the Lisbon Bottom Chute, the chute between the right bank and island located at river mile 219, and a shallow channel running between a large sandbar complex and the channel border adjacent to Lisbon Bottom. Species richness in the chutes (35 species) was greater than that of the adjacent river (23 species). Big River species (40%) dominated the chute samples, followed by Wide-ranging at 31% Cand Prairie Cut 14%. The river samples contained equal numbers of Wide-ranging species (35%) and Big River species (35%) with 17% Prairie species. Differences in fish guild diversity and species richness may be due to numerous factors including sampling effort and sampling season. River samples were collected only in Study 3 in October; chute samples were collected in July, August, and October. Fish may have been using the chute in July and August to spawn, feed, or escape high river levels. The Lisbon Bottom Chute is a truly unique feature of the Lower Missouri River. It is the first naturally created side channel to develop since the U.S. Army Corps of Engineers tamed the river. The Corps eliminated 89% of the islands in the Missouri River between 1879 and 1954 (Funk and Robinson 1974). The chutes between the islands and the shore were shallower with less current than the main channel. These areas provided diversity to the Missouri River fish habitat, serving as nursery and feeding areas. The Lisbon Bottom Unit of the Big Muddy National Fish and Wildlife Refuge will continue to be studied in an effort to understand the complex role these areas play in river systems.

Missouri↗

USGS2018

Quantifying anthropogenic contributions to century-scale groundwater salinity changes, San Joaquin Valley, California, USA

Total dissolved solids (TDS) concentrations in groundwater tapped for beneficial uses (drinking water, irrigation, freshwater industrial) have increased on average by about 100 mg/L over the last 100 years in the San Joaquin Valley, California (SJV). During this period land use in the SJV changed from natural vegetation and dryland agriculture to dominantly irrigated agriculture with growing urban areas. Century-scale salinity trends were evaluated by comparing TDS concentrations and major ion compositions of groundwater from wells sampled in 1910 (Historic) to data from wells sampled in 1993-2015 (Modern). TDS concentrations in subregions of the SJV, the southern (SSJV), western (WSJV), northeastern (NESJV), and southeastern (SESJV) were calculated using a cell-declustering method. TDS concentrations increased in all regions, with the greatest increases found in the SSJV and SESJV. Evaluation of the Modern data from the NESJV and SESJV found higher TDS concentrations in recently recharged (post-1950) groundwater from shallow (< 50 m) wells surrounded predominantly by agricultural land uses, while premodern (pre-1950) groundwater from deeper wells, and recently recharged groundwater from wells surrounded by mainly urban, natural, and mixed land uses had lower TDS concentrations, approaching the TDS concentrations in the Historic groundwater. For the NESJV and SESJV, inverse geochemical modeling with PHREEQC indicated that weathering of primary silicate minerals accounted for the majority of the increase in TDS concentrations, contributing more than nitrate from fertilizers and sulfate from soil amendments combined. Bicarbonate showed the greatest increase among major ions, resulting from enhanced silicate weathering due to recharge of irrigation water enriched in CO2 during the growing season. The results of this study demonstrate that large anthropogenic changes to the hydrologic regime, like massive development of irrigated agriculture in semi-arid areas like the SJV, can cause large changes in groundwater quality on a regional scale.

California↗

USGS2003

Extraordinary phase separation and segregation in vent fluids from the southern East Pacific Rise

The discovery of Brandon vent on the southern East Pacific Rise is providing new insights into the controls on midocean ridge hydrothermal vent fluid chemistry. The physical conditions at the time ofsampling (287 bar and 405??C) place the Brandon fluids very close to the critical point of seawater (298 bar and 407??C). This permits in situ study of the effects of near criticalphenomena, which are interpreted to be the primary cause of enhanced transition metal transport in these fluids. Of the five orifices on Brandon sampled, three were venting fluids with less than seawater chlorinity, and two were venting fluids with greater than seawater chlorinity. The liquid phase orifices contain 1.6-1.9 times the chloride content of the vapors. Most other elements, excluding the gases, have this same ratio demonstrating the conservative nature of phase separation and the lack of subsequent water-rock interaction. The vapor and liquid phases vent at the same time from orifices within meters of each other on the Brandon structure. Variations in fluid compositions occur on a time scale of minutes. Our interpretation is that phase separation and segregation must be occurring 'real time' within the sulfide structure itself. Fluids from Brandon therefore provide an unique opportunity to understand in situ phase separation without the overprinting of continued water-rock interaction with the oceanic crust, as well as critical phenomena. ?? 2002 Elsevier Science B.V. All rights reserved.

Earth and Planetary Science Letters↗

USGS1996

Use of 13C NMR and ftir for elucidation of degradation pathways during natural litter decomposition and composting I. early stage leaf degradation

Oxidative degradation of plant tissue leads to the formation of natural dissolved organic carbon (DOC) and humus. Infrared (IR) and 13C nuclear magnetic resonance (NMR) spectrometry have been used to elucidate the chemical reactions of the early stages of degradation that give rise to DOC derived from litter and compost. The results of this study indicate that oxidation of the lignin components of plant tissue follows the sequence of O-demethylation, and hydroxylation followed by ring-fission, chain-shortening, and oxidative removal of substituents. Oxidative ring-fission leads to the formation of carboxylic acid groups on the cleaved ends of the rings and, in the process, transforms phenolic groups into aliphatic alcoholic groups. The carbohydrate components are broken down into aliphatic hydroxy acids and aliphatic alcohols.

Soil Science↗

USGS2018

Understanding the influence of nutrients on stream ecosystems in agricultural landscapes

Sustaining the quality of the Nation’s water resources and the health of our diverse ecosystems depends on the availability of sound water-resources data and information to develop effective, science-based policies. Effective management of water resources also brings more certainty and efficiency to important economic sectors. Taken together, these actions lead to immediate and long-term economic, social, and environmental benefits that make a difference to the lives of the almost 400 million people projected to live in the United States by 2050. In 1991, Congress established the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) to address where, when, why, and how the Nation’s water quality has changed, or is likely to change in the future, in response to human activities and natural factors. Since then, NAWQA has been a leading source of scientific data and knowledge used by national, regional, State, and local agencies to develop science-based policies and management strategies to improve and protect water resources used for drinking water, recreation, irrigation, energy development, and ecosystem needs ( https://water.usgs.gov/nawqa/applications/ ). Plans for the third decade of NAWQA (2013–23) address priority water-quality issues and science needs identified by NAWQA stakeholders, such as the Advisory Committee on Water Information and the National Research Council, and are designed to meet increasing challenges related to population growth, increasing needs for clean water, and changing land-use and weather patterns. Excess nutrients are a pervasive problem of streams, lakes, and coastal waters. The current report, “The Quality of Our Nation’s Waters—Understanding the Effects of Nutrients on Stream Ecosystems in Agricultural Landscapes,” presents a summary of results from USGS investigations conducted from 2003 to 2011 on processes that influence nutrients and how nutrient enrichment can alter biological components of agricultural streams. This study included collecting data from 232 sites distributed among eight study areas. This report summarizes findings on processes that influence nutrients and how nutrient enrichment can alter biological communities in agricultural streams. These findings are relevant to local, State, regional, and national decision-makers involved in efforts to (1) better understand the influence of nutrients on agricultural streams, (2) develop nutrient criteria for streams and rivers, (3) reduce nutrients to streams and downstream receiving waters, and (4) develop tools for tracking nutrient and biological conditions following nutrient reduction strategies. All NAWQA reports are available online at https://water.usgs.gov/nawqa/bib/ . We hope this publication will provide you with insights and information to meet your water-resource needs and will foster increased citizen awareness and involvement in the protection and restoration of our Nation’s waters. The information in this report is intended primarily for those interested or involved in resource management and protection, conservation, regulation, and policymaking at the regional and national levels.

Central Columbia-Yakima River Basins, Great River ↗

USGS2010

Demographic studies of Joshua trees in Mojave Desert National Parks: demography with emphasis on germination and recruitment

The study of population change with regard to reproduction, seed dispersal, and germination, establishment, growth, and survival/mortality is known as demography. Demographic studies provide managers with information to assess future trends on the density, distribution, health, and population changes of importance or value, including Joshua trees (Yucca brevifolia). Demographic research provides the potential to understand the combined impacts of climate change and land-use practices and determine if strategies for protecting important species are likely to succeed or fall short of management goals and will identify factors that have the potential to de-stabilize populations outside the realm of natural variation so that management strategies can be developed to circumvent challenges for key species, processes, and ecosystems. The National Park Service and US Geological Survey are collaborating to collect demographic information about the demographics of Joshua tree in the Mojave Desert.

Arizona;California;Nevada↗

USGS2006

Controls on mercury and methylmercury deposition for two watersheds in Acadia National Park, Maine

Throughfall and bulk precipitation samples were collected for two watersheds at Acadia National Park, Maine, from 3 May to 16 November 2000, to determine which landscape factors affected mercury (Hg) deposition. One of these watersheds, Cadillac Brook, burned in 1947, providing a natural experimental design to study the effects of forest type on deposition to forested watersheds. Sites that face southwest received the highest Hg deposition, which may be due to the interception of cross-continental movement of contaminated air masses. Sites covered with softwood vegetation also received higher Hg deposition than other vegetation types because of the higher scavenging efficiency of the canopy structure. Methyl mercury (MeHg) deposition was not affected by these factors. Hg deposition, as bulk precipitation and throughfall was lower in Cadillac Brook watershed (burned) than in Hadlock Brook watershed (unburned) because of vegetation type and watershed aspect. Hg and MeHg inputs were weighted by season and vegetation type because these two factors had the most influence on deposition. Hg volatilization was not determined. The total Hg deposition via throughfall and bulk precipitation was 9.4 ??g/m2/year in Cadillac Brook watershed and 10.2 ??g/m2/year in Hadlock Brook watershed. The total MeHg deposition via throughfall and bulk precipitation was 0.05 ??g/m2/year in Cadillac Brook watershed and 0.10 ??g/m2/year in Hadlock Brook watershed. ?? Springer Science + Business Media B.V. 2006.

Environmental Monitoring and Assessment↗

USGS2013

Naturally occurring contaminants in the Piedmont and Blue Ridge crystalline-rock aquifers and Piedmont Early Mesozoic basin siliciclastic-rock aquifers, eastern United States, 1994–2008

Groundwater quality and aquifer lithologies in the Piedmont and Blue Ridge Physiographic Provinces in the eastern United States vary widely as a result of complex geologic history. Bedrock composition (mineralogy) and geochemical conditions in the aquifer directly affect the occurrence (presence in rock and groundwater) and distribution (concentration and mobility) of potential naturally occurring contaminants, such as arsenic and radionuclides, in drinking water. To evaluate potential relations between aquifer lithology and the spatial distribution of naturally occurring contaminants, the crystalline-rock aquifers of the Piedmont and Blue Ridge Physiographic Provinces and the siliciclastic-rock aquifers of the Early Mesozoic basin of the Piedmont Physiographic Province were divided into 14 lithologic groups, each having from 1 to 16 lithochemical subgroups, based on primary rock type, mineralogy, and weathering potential. Groundwater-quality data collected by the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program from 1994 through 2008 from 346 wells and springs in various hydrogeologic and land-use settings from Georgia through New Jersey were compiled and analyzed for this study. Analyses for most constituents were for filtered samples, and, thus, the compiled data consist largely of dissolved concentrations. Concentrations were compared to criteria for protection of human health, such as U.S. Environmental Protection Agency (USEPA) drinking water maximum contaminant levels and secondary maximum contaminant levels or health-based screening levels developed by the USGS NAWQA Program in cooperation with the USEPA, the New Jersey Department of Environmental Protection, and Oregon Health & Science University. Correlations among constituent concentrations, pH, and oxidation-reduction (redox) conditions were used to infer geochemical controls on constituent mobility within the aquifers. Of the 23 trace-element constituents evaluated, arsenic, manganese, and zinc were detected in one or more water samples at concentrations greater than established human health-based criteria. Arsenic concentrations typically were less than 1 microgram per liter (µg/L) in most groundwater samples; however, concentrations of arsenic greater than 1 µg/L frequently were detected in groundwater from clastic lacustrine sedimentary rocks of the Early Mesozoic basin aquifers and from metamorphosed clastic sedimentary rocks of the Piedmont and Blue Ridge crystalline rock aquifers. Groundwater from these rock units had elevated pH compared to other rock units evaluated in this study. Of the nine samples for which arsenic concentration was greater than 10 µg/L, six were classified as oxic and three as anoxic, and seven had pH of 7.2 or greater. Manganese concentrations typically were less than 10 µg/L in most samples; however, 8.3 percent of samples from the Piedmont and Blue Ridge crystalline-rock aquifers and 3.0 percent of samples from the Early Mesozoic basin siliciclastic rock aquifers had manganese concentrations greater than the 300-µg/L health-based screening level. The positive correlation of manganese with iron and ammonia and the negative correlation of manganese with dissolved oxygen and nitrate are consistent with the reductive dissolution of manganese oxides in the aquifer. Zinc concentrations typically were less than 10 µg/L in the groundwater samples considered in the study, but 0.4 percent and 5.5 percent of the samples had concentrations greater than the health-based screening level of 2,000 µg/L and one-tenth of the health-based screening level, respectively. The mean rank concentration of zinc in groundwater from the quartz-rich sedimentary rock lithologic group was greater than that for other lithologic groups even after eliminating samples collected from wells constructed with galvanized casing. Approximately 90 percent of 275 groundwater samples had radon-222 concentrations that were greater than the proposed alternative maximum contaminant level of 300 picocuries per liter. In contrast, only 2.0 percent of 98 samples had combined radium (radium-226 plus radium-228) concentrations greater than the maximum contaminant level of 5.0 picocuries per liter, and 0.6 percent of 310 samples had uranium concentrations greater than the maximum contaminant level of 30 µg/L. Radon concentrations were highest in the Piedmont and Blue Ridge crystalline-rock aquifers, especially in granite, and elevated median concentrations were noted in the Piedmont Early Mesozoic basin aquifers, but without the extreme maximum concentrations found in the crystalline rocks (granites). Although the siliciclastic lithologies had a greater frequency of elevated uranium concentrations, radon and radium were commonly detected in water from both siliciclastic and crystalline lithologies. Uranium concentrations in groundwater from clastic sedimentary and clastic lacustrine/evaporite sedimentary lithologic groups within the Early Mesozoic basin aquifers, which had median concentrations of 3.6 and 3.1 µg/L, respectively, generally were higher than concentrations for other siliciclastic lithologic groups, which had median concentrations less than 1 µg/L. Although 89 percent of the 260 samples from crystalline-rock aquifers had uranium concentrations less than 1 µg/L, 0.8 percent had uranium concentrations greater than the 30-µg/L maximum contaminant level, and 6.5 percent had concentrations greater than 3 µg/L.

Alabama;Delaware;Georgia;Maryl;New Jersey;North Ca↗

USGS2021

Disentangling stationary and dynamic estuarine fish habitat to inform conservation: Species-specific responses to physical habitat and water quality in San Francisco Estuary

Estuaries represent critical aquatic habitat that connects surface water distributed between Earth’s landmasses and oceans. They are dynamic transitional ecosystems, which provide important habitat for fishes and other aquatic organisms. Effective conservation of species inhabiting estuaries requires knowledge of the habitat features that drive their abundance and distribution. We sought to elucidate how stationary (i.e., wetlands, shoals, and channels) and dynamic (i.e., salinity, temperature, turbidity, and chlorophyll concentration) habitat features interact to drive distributions of individual fish species. The Pacific coast of the conterminous United States has over 400 estuaries of various types. The largest (historical surface area) is San Francisco Estuary, California. We conducted extensive field observations of fishes in the central San Francisco Estuary among stationary habitat types (i.e., wetland, shoal, and channel) over a 19-month period encompassing substantial variability in dynamic water quality conditions. Most of the species observed, especially native species of special management interest, were associated with tidal wetland habitat. Few species exhibited associations with water quality conditions driven by seasonal (temperature) or a combination of broad- and fine-scale ecosystem processes (salinity and turbidity). Our study provides (1) an empirical demonstration of how researchers can deal with the complex and dynamic expressions of habitat in estuarine systems to address urgent natural resource problems and (2) a clear demonstration of the urgent need for habitat restoration and its likely outcome in systems such as San Francisco Estuary. Restoration of suitable tidal wetland habitat on the West Coast of the United States is likely to be an effective conservation tool to support estuarine fishes given that over 90% of historical tidal wetland habitat in San Francisco Estuary and 85% of vegetated wetland habitat along the Pacific coast of the United States has been lost due to human modification.

California↗

USGS1891

Index to the known fossil insects of the world, including myriapods and arachnids

With the view of furthering study in the too neglected field of fossil insects, I transmit herewith for publication the card catalogue of described fossil insects which I have used for twenty years and kept constantly up to date, and which has greatly facilitated my own researches. It is believed to be practically complete. At least where insects are figured, and in many other cases where they are the first or only references from a given locality, entries are given where only the genus, the family, or even the order is mentioned. This has been done because the early literature of fossil insects is essentially vague and general, but it should not for that reason be wholly overlooked ; and to-day our knowledge of the occurrence of insects of a particular locality, even when of recent discovery, is not infrequently confined to statements of a general nature, which, if not brought to view or mind in a list like this, would be lost sight of, while their recognition may lead to further local investigation, to the earlier benefit of science. It is in no sense a systematic catalogue, and except occasionally in the notes contains no immediate results of investigation. No questions of synonymy are settled. The entries are made as the authors quoted gave them, with only the corrections of spelling required; it follows that the same insect appears at several points, to which the student is referred by full cross-references, and that more than one insect may (though probably rarely does) figure under one name. In one or two such instances, where the same name has been given by inadvertence to two totally different creatures, the later one is separated from the earlier. For convenience' sake, the entries are grouped into large sections, nearly identical with those I have employed in my systematic review of fossil insects (Bulletin 31, U. S. Geological Survey), by which method the insects from the Primary, Secondary, and Tertiary rocks are kept distinct; but otherwise the entries are purely alphabetical under the orders. It should be noticed, however, that the vague references to groups higher than genera are brought together at the beginning of each alphabet, first the most vague, and then those which permit some alphabetization. In these cases the primary or secondary alphabetization is first by authors, second by dates, and in all cases where under one entry there is more than one date the order therein is chronological. In a previous bulletin (Bulletin 69, U. S. Geological Survey) is given a complete bibliography of the literature from which these entries are taken, and the two works are thus complementary to each other.

Bulletin↗

USGS1996

Effect of surface area and chemisorbed oxygen on the SO2 adsorption capacity of activated char

The objective of this study was to determine whether activated char produced from Illinois coal could be used effectively to remove sulfur dioxide from coal combustion flue gas. Chars were prepared from a high-volatile Illinois bituminous coal under a wide range of pyrolysis and activation conditions. A novel char preparation technique was developed to prepare chars with SO2 adsorption capacities significantly greater than that of a commercial activated carbon. In general, there was no correlation between SO2 adsorption capacity and surface area. Temperature-programmed desorption (TPD) was used to determine the nature and extent of carbon-oxygen (C-O) complexes formed on the char surface. TPD data revealed that SO2 adsorption was inversely proportional to the amount of C-O complex. The formation of a stable C-O complex during char preparation may have served only to occupy carbon sites that were otherwise reactive towards SO2 adsorption. A fleeting C(O) complex formed during SO2 adsorption is postulated to be the reaction intermediate necessary for conversion of SO2 to H2SO4. Copyright ?? 1996 Elsevier Science Ltd.

Fuel↗