Geology Reports⌕ Search

SEARCH · Geology Reports

Results for “Humans and Nature”

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

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 955 records · Page 53Linked to original sources
USGS2011

Influence of dissolved organic matter on the environmental fate of metals, nanoparticles, and colloids

We have known for decades that dissolved organic matter (DOM) plays a critical role in the biogeochemical cycling of trace metals and the mobility of colloidal particles in aquatic environments. In recent years, concerns about the ecological and human health effects of metal-based engineered nanoparticles released into natural waters have increased efforts to better define the nature of DOM interactions with metals and surfaces. Nanomaterials exhibit unique properties and enhanced reactivities that are not apparent in larger materials of the same composition 1,2 or dissolved ions of metals that comprise the nanoparticles. These nanoparticle-specific properties generally result from the relatively large proportion of the atoms located at the surface, which leads to very high specific surface areas and a high proportion of crystal lattice imperfections relative to exposed surface area. Nanoscale colloids are ubiquitous in nature,2 and many engineered nanomaterials have analogs in the natural world. The properties of these materials, whether natural or manmade, are poorly understood, and new challenges have been presented in assessing their environmental fate. These challenges are particularly relevant in aquatic environments where interactions with DOM are key, albeit often overlooked, moderators of reactivity at the molecular and nanocolloidal scales.

Environmental Science & Technology↗
USGS2018

Trophic implications of a phenological paradigm shift: Bald eagles and salmon in a changing climate

Climate change influences apex predators in complex ways, due to their important trophic position, capacity for resource plasticity, and sensitivity to numerous anthropogenic stressors. Bald eagles, an ecologically and culturally significant apex predator, congregate seasonally in high densities on salmon spawning rivers across the Pacific Northwest. One of the largest eagle concentrations is in the Skagit River watershed, which connects the montane wilderness of North Cascades National Park to the Puget Sound. Using multiple long‐term datasets, we evaluated local bald eagle abundance in relation to chum and coho salmon availability; salmon phenology; and the number and timing of flood events in the Skagit. We analysed changes over time as a reflection of climate change impacts, as well as differences between managed and unmanaged portions of the river. We found that peaks in chum salmon and bald eagle presence have advanced at remarkably similar rates ( c . 0.45 days/year), suggesting synchronous phenological responses within this trophic relationship. Yet the temporal relationship between chum salmon spawning and flood events, which remove salmon carcasses from the system, has not remained constant. This has resulted in a paradigm shift whereby the peak of chum spawning now occurs before the first flood event of the season rather than after. The interval between peak chum and first flood event was a significant predictor of bald eagle presence: as this interval grew over time (by nearly one day per year), bald eagle counts declined, with a steady decrease in bald eagle observations since 2002. River section was also an important factor, with fewer flood events, and more eagle observations occurring in the river section experiencing direct hydroelectric flow management. Synthesis and applications . The effects of climate change and hydroelectric management contribute to a complex human footprint in the North Cascades National Park, an otherwise largely natural ecosystem. By accounting for the differential phenological impacts of climate change on bald eagles, salmon, and flood events, Park managers and the operators of the hydroelectric system can more effectively ensure the resilience of the eagle–salmon relationship along the Skagit River.

Washington↗
USGS2022

Ecological divergence of wild birds drives avian influenza spillover and global spread

The diversity of influenza A viruses (IAV) is primarily hosted by two highly divergent avian orders: Anseriformes (ducks, swans and geese) and Charadriiformes (gulls, terns and shorebirds). Studies of IAV have historically focused on Anseriformes, specifically dabbling ducks, overlooking the diversity of hosts in nature, including gull and goose species that have successfully adapted to human habitats. This study sought to address this imbalance by characterizing spillover dynamics and global transmission patterns of IAV over 10 years at greater taxonomic resolution than previously considered. Furthermore, the circulation of viral subtypes in birds that are either host-adapted (low pathogenic H13, H16) or host-generalist (highly pathogenic avian influenza—HPAI H5) provided a unique opportunity to test and extend models of viral evolution. Using Bayesian phylodynamic modelling we uncovered a complex transmission network that relied on ecologically divergent bird hosts. The generalist subtype, HPAI H5 was driven largely by wild geese and swans that acted as a source for wild ducks, gulls, land birds, and domestic geese. Gulls were responsible for moving HPAI H5 more rapidly than any other host, a finding that may reflect their long-distance, pelagic movements and their immuno-naïve status against this subtype. Wild ducks, long viewed as primary hosts for spillover, occupied an optimal space for viral transmission, contributing to geographic expansion and rapid dispersal of HPAI H5. Evidence of inter-hemispheric dispersal via both the Pacific and Atlantic Rims was detected, supporting surveillance at high latitudes along continental margins to achieve early detection. Both neutral (geographic expansion) and non-neutral (antigenic selection) evolutionary processes were found to shape subtype evolution which manifested as unique geographic hotspots for each subtype at the global scale. This study reveals how a diversity of avian hosts contribute to viral spread and spillover with the potential to improve surveillance in an era of rapid global change.

PLoS Pathogens↗
USGS2019

Southern sea otter (Enhydra lutris nereis) population biology at Big Sur and Monterey, California --Investigating the consequences of resource abundance and anthropogenic stressors for sea otter recovery

The range of the southern sea otter ( Enhydra lutris nereis ) spans most of the central California coast from Half Moon Bay to Gaviota. Some coastal areas within this range are heavily developed and highly impacted by humans, while other areas are wild and largely pristine. Determining the relative importance of food resource abundance, environmental conditions, and anthropogenic increases in pathogens and pollutants to population change in sea otters is critical to understanding limitations to population growth. To investigate the causal links between the sluggish population growth of sea otters in central California and factors that could be driving variation in survival and reproduction, we designed a study to compare two distinct subpopulations—one in an area of low human impact (Big Sur) and one in an area of high human impact (Monterey). Between 2008 and 2011, the U.S. Geological Survey and collaborators conducted a telemetry-based study of sea otters at these two locations. The results of this study were not consistent with the hypothesis that sea otters adjacent to human population centers (Monterey) experience higher exposure to pollutants and pathogens than those in lower impacted areas (Big Sur). In fact, based on serological analysis, female sea otters from Big Sur showed higher exposure rates to Toxoplasma gondii than did female otters from Monterey, while domoic acid exposure appeared to be similar at both sites. Gene expression (specifically transcription) analysis did not indicate any consistent differences between the two populations that would have suggested a response to pathogen or toxin exposure, although there were temporal changes in gene transcription for sea otters at Big Sur following potential exposure to run-off from wildfires that occurred during the study. Together, these metrics suggest that variation in exposure to environmental stressors occurred, but patterns were not clearly attributable to differences in human population densities or land-use patterns. When compared to Monterey, sea otters in Big Sur spent more time feeding, had a higher degree of dietary specialization, were in poorer body condition, and had lower survival rates (both pups and adults). Together, these metrics suggest that otters at Big Sur had greater nutritional stress, consistent with lower per-capita resource abundance. Overall, study results indicate that density-dependent population regulation, mediated by per-capita resource abundance, is the most significant factor currently limiting population growth in the center part of the range. Additionally, spatial and temporal variation in environmental and anthropogenic stressors also can affect sea otter health, although patterns of variation are complex and are not simply a function of proximity to human populations. We also found that exposure to environmental stressors (either natural or anthropogenic in origin) often is associated with resource limitation. Finally, our results indicate that sea otter populations are structured at relatively small spatial scales, and the processes that regulate population abundance (including density-dependent resource abundance) also occur at these smaller, more local scales.

California↗
USGS2002

Distribution and mass loss of volatile organic compounds in the surficial aquifer at sites FT03, LF13, and WP14/LF15, Dover Air Force Base, Delaware, November 2000–February 2001

Ground-water and surface-water sampling was conducted in the natural attenuation study area in the East Management Unit of Dover Air Force Base, Delaware to determine the distributions of volatile organic compounds in the vicinity of four sites?Fire Training Area Three, the Rubble Area Landfill, the Receiver Station Landfill, and the Liquid Waste Disposal Landfill. This work was done by the U.S. Geological Survey, in cooperation with the U.S. Air Force, as part of an ongoing assessment of the effectiveness of natural attenuation at these sites. The specific objectives of the study were to (1) determine the areal and vertical extent of the contaminant plumes and source areas, (2) measure volatile organic compound concentrations in ground-water discharge areas and in surface water under base-flow conditions, (3) evaluate the potential for off-site migration of the mapped plumes, and (4) estimate the amount of mass loss downgradient of the Liquid Waste Disposal and Receiver Station Landfills. A direct-push drill rig and previously installed multi-level piezometers were used to determine the three-dimensional distributions of volatile organic compounds in the 30?60-foot-thick surficial aquifer underlying the natural attenuation study area. A hand -driven mini-piezometer was used to collect ground-water samples in ground-water discharge areas. A total of 319 ground-water and 4 surface-water samples were collected from November 2000 to February 2001 and analyzed for chlorinated solvents and fuel hydrocarbons. The contaminant plumes migrating from Fire Training Area Three and the Rubble Area Landfill are approximately 500 feet and 800 feet, respectively, in length. These plumes consist predominantly of cis-1,2-dichloroethene, a daughter product, indicating that extensive dechlorination of tetrachloroethene and trichloroethene has occurred at these sites. With an approximate length of 2,200 feet, the plume migrating from the Receiver Station and Liquid Waste Disposal Landfills is the largest of the three plumes in the East Management Unit. In this plume, the parent compounds, tetrachloroethene and trichloroethene, as well as cis-1,2-dichloroethene, are present downgradient of the source. Vinyl chloride was not detected in the natural attenuation study area. Vertical water-quality profiles indicate that volatile organic compounds are present mainly in the upper part of the surficial aquifer. Plumes of fuel hydrocarbon constituents were not detected in the natural attenuation study area. Volatile organic compounds were present at concentrations above detection limits in 6 of 14 samples collected from the aquifer underlying the bed of Pipe Elm Branch and the drainage ditch adjacent to Fire Training Area Three, indicating that the plumes migrating from Fire Training Area Three and the Receiver Station and Liquid Waste Disposal Landfills are reaching these ground-water discharge areas. In contrast, sampling results indicated that the plume from the Rubble Area Landfill does not reach these ground-water discharge areas. Trichloroethene was present above detection limits in one of four surface-water samples collected from Pipe Elm Branch and the drainage ditch adjacent to Fire Training Area Three. The trichloroethene concentration is below applicable Delaware Department of Natural Resources and Environmental Control surface-water-quality standards for human health. An assessment of chlorinated-solvent mass loss in the plume migrating from the Receiver Station and Liquid Waste Disposal Landfills indicates that tetrachloroethene and trichloroethene mass loss downgradient of the source is negligible. Cis-1,2-dichloroethene, however, appears to biodegrade by an unidentified reaction in the plume. Plan-view maps of the plume migrating from the Receiver Station and Liquid Waste Disposal Landfills indicate that tetrachloroethene, trichloroethene, and cis-1,2-dichloroethene may migrate off Dover Air Force Base property approximately 1,500 f

Delaware↗
USGS1995

Wolves and caribou in Denali National Park, Alaska

Management of gray wolves ( Canis lupus ) and their prey in interior Alaska has been controversial for three decades (Harbo and Dean 1983). Recently, debate was rekindled with renewed interest in wolf control to bolster two populations of caribou ( Rangifer tarandus ). Our research in Denali National Park provides insights into the declines in caribou numbers over the last few years that are the basis of recent wolf control proposals. Our observations of fluctuating populations also illustrate the complexity of managing these predator-prey systems to meet a diverse array of public interests. Wolves and caribou are two components of the large mammal community of Denali National Park that also includes grizzly bears ( Ursus arctos ), moose ( Alces alces ), and Dall sheep ( Ovis dalli ). With the 1980 park expansion to more than 18,800 km2 (7,300 mi2) of central Alaska, this large mammal system became the only one of its kind that is virtually unaffected by human harvest. Therefore, Denali provides a unique opportunity to understand the natural interactions of these species and serves as a baseline for comparison with areas where hunting or other active wildlife management occurs. We have studied Denali's wolves and caribou since 1986 to determine their numbers and status and understand their natural interactions in this protected subarctic ecosystem. Our studies began near the end of more than a decade of mostly light winter snowfalls of around 100 cm (39 in)/yr. Since winter 1988-89, we have experienced five consecutive winters with above-average snowfalls, including two record-setting years. During winters 1990-91 and 1992-93, more than 390 cm (154 in) of snow fell, four times as much as in the early years of our study. This change in snowfall had profound effects on the wildlife in central Alaska. The population trends of Denali's caribou and wolves are strong evidence of the natural fluctuations to be expected in species inhabiting such dynamic and variable environments.

Alaska↗
USGS1986

An overview of raptor conservation in Latin America

Prior to the last decade, biological studies of raptorial birds in Latin America were almost nonexistent. For many species little more was known than their general range and habitat type. The last few years have seen the opening of a door to what will surely be a flood of scientific investigations. Ultimately, the survival of raptor communities in Latin America depends not only on research but also on several other equally significant conservation efforts. These typically appear in the following order: first, appropriate legislation must be enacted and enforced to provide legal protection; second, the public must be educated concerning the value of wildlife; third, substantial blocks of favourable habitat must be identified and preserved; fourth, economic incentives must be generated so that the local human populations actually benefit from the preservation of vulnerable wildlife and natural habitats; and finally, the long-term success of all of these efforts in each nation depends on the attainment of political, economic and social stability.

Birds of Prey Bulletin↗
USGS2004

Science data in support of environmental health studies in the U.S.-Mexico border region

The border region of the United States and Mexico encompasses a vast and diverse array of physical settings and habitats that include wetlands, deserts, rangeland, mountains, and forests, which are unique in terms of the diversity of their water, mineral, and biological resources. The region is interconnected economically, politically, and socially owing to its binational heritage. In 1995, nearly 11 million people lived immediately adjacent to the border. By one account, that population could more than double by 2020. This rapid population growth and consequent economic development and land-use changes are pushing the limits of environmental sustainability and quality. Infrastructure development has lagged behind the rapid growth of the region, resulting in a shortage of water for municipal, agricultural, and industrial uses. These stressors threaten the quality of life in the region and raise concerns about the interdependence of environmental quality and human health. To allow for continued economic growth while protecting the area’s natural resources and fostering a high quality of life, the United States and Mexico need an improved understanding of the threats posed by these anthropogenic changes. Issues of particular concern include (1) contaminants in ground water, surface water, and biota from agricultural, municipal, and industrial activities; (2) airborne pollutants from fossil-fuel combustion and other activities; (3) contaminants from past and present mining activities and mineral deposits; and (4) pathogens, pharmaceuticals, hormones, and other contaminants released in treated and untreated human and animal wastewaters.

Fact Sheet↗
USGS2021

Environmental factors predicting the orientation of sea turtle hatchlings on a naturally lighted beach: A baseline for light-management goals

On sea turtle nesting beaches, artificial lighting associated with human development interferes with hatchling orientation from nest to sea. Although hatchling disorientation has been documented for many beaches, data that managers can use in understanding, predicting, and managing the issue are of limited detail. The present study provides baseline hatchling orientation data that can be compared to those from beaches with artificial lighting to prioritize light-management efforts there. In 2014, the precision of hatchling orientation was quantified for 87 nests on a naturally lighted beach that had little to no artificial lighting. Precision of hatchling orientation was regressed against seven environmental variables: beach slope, distance from nest to dune, dune height, apparent dune silhouette height relative to nest site, moon illumination percentage, cloud cover percentage, and relative humidity. Results favored a regression model that included distance from nest to dune, with shorter distances from the dune predicting a narrower angular range (i.e., greater precision) of hatchling orientation. The study confirmed findings of an earlier laboratory experiment that highlighted the importance to accurate hatchling orientation of a dark silhouette (dune) on the side of the nest site opposite the ocean side. Reducing artificial light and promoting the planting of pioneer plants that assist dune formation can increase hatchling survival.

Florida↗
USGS2023

Cross-continental evaluation of landscape-scale drivers and their impacts to fluvial fishes: Understanding frequency and severity to improve fish conservation in Europe and the United States

Fluvial fishes are threatened globally from intensive human landscape stressors degrading aquatic ecosystems. However, impacts vary regionally, as stressors and natural environmental factors differ between ecoregions and continents. To date, a comparison of fish responses to landscape stressors over continents is lacking, limiting understanding of consistency of impacts and hampering efficiencies in conserving fishes over large regions. This study addresses these shortcomings through a novel, integrative assessment of fluvial fishes throughout Europe and the conterminous United States. Using large-scale datasets, including information on fish assemblages from more than 30,000 locations on both continents, we identified threshold responses of fishes summarized by functional traits to landscape stressors including agriculture, pasture, urban area, road crossings, and human population density. After summarizing stressors by catchment unit (local and network) and constraining analyses by stream size (creeks vs. rivers), we analyzed stressor frequency (number of significant thresholds) and stressor severity (value of identified thresholds) within ecoregions across Europe and the United States. We document hundreds of responses of fish metrics to multi-scale stressors in ecoregions across two continents, providing rich findings to aid in understanding and comparing threats to fishes across the study regions. Collectively, we found that lithophilic species and, as expected, intolerant species are most sensitive to stressors in both continents, while migratory and rheophilic species are similarly strongly affected in the United States. Also, urban land use and human population density were most frequently associated with declines in fish assemblages, underscoring the pervasiveness of these stressors in both continents. This study offers an unprecedented comparison of landscape stressor effects on fluvial fishes in a consistent and comparable manner, supporting conservation of freshwater habitats in both continents and worldwide.

Europe↗
USGS2019

Predicting surf zone injuries along the Delaware coast using a Bayesian network

Personnel at Beebe Healthcare in Lewes, Delaware, collected surf zone injury (SZI) data for eight summer seasons from 2010 through 2017. Data include, but are not limited to, time of injury, gender, age, and activity. More than 2000 SZI events, including 196 spinal injuries and 6 fatalities, occurred at the five most populated beaches along the 25 miles of Atlantic-fronting coast. SZI are predominantly wave related incidents associated with wading (50.1%), body surfing (18.4%), and body boarding (13.3%). The episodic nature of SZI indicate the importance of linking the environmental conditions and human behavior in the surf zone to predict days with high injury rates. Higher order statistics are necessary to effectively consider all associated factors related to SZI. Two Bayesian networks (BN) were constructed to model SZI and predict changes in injury rate (proportion of injuries to bathers) and injury likelihood (probability of at least one injury occurrence) on an hourly basis. The models incorporate environmental data collected by weather stations, wave gauges, and researcher personnel on the beach. The models include prior (e.g., historic) information to infer relationships between provided parameters. Sensitivity analysis determined the most influential parameters related to injury rates were significant wave height, foreshore slope, and water temperature. Exposure parameters (e.g., air temperature) influenced the number of people in the water, resulting in strong correlation between injury likelihood and the related meteorological conditions (variance reduction > 0.4%). Log likelihood ratio (LLR) scores indicate the network predicts SZI likelihood during any specified hour with more skill than prior predictions with the best performing model improving prediction 69.1% of the time (LLR = 69.1%). An alternative BN predicting injury rate performed worse with the prior probability model out predicting the injury rate network (positive LLR = 36.7%). Issues persist with predicting SZI that have an LLR ≪ -1 (< 5% of 2017 injuries) and occur in conditions different than when most other SZI occur. Better understanding of SZI will improve awareness techniques to both educate beachgoers and assist beach patrol decision making during high risk conditions.

Delaware↗
USGS2005

Geography for a Changing World - A science strategy for the geographic research of the U.S. Geological Survey, 2005-2015

This report presents a science strategy for the geographic research of the U.S. Geological Survey (USGS) for the years 2005-2015. The common thread running through the vision, mission, and science goals presented in the plan is that USGS geographers will provide national leadership to understand coupled human-environmental systems in the face of land change and will deliver pertinent information to decisionmakers on the vulnerability and resilience of these systems. We define land change science as the study of the human and environment dynamics that give rise to changed land use, cover, and surface form. A number of realities shape the strategic context of this plan: The Department of Interior Strategic Plan focuses on meeting society’s resource needs and sustaining the Nation’s life support systems, underscoring the importance of characterizing and understanding coupled human-environmental systems. In redefining its mission in the mid-1990s, the USGS envisions itself as an integrated natural science and information agency. The USGS will assume a national leadership role in the use of science to develop knowledge about the web of relations that couple biophysical and human systems and translate this knowledge into unbiased, reliable information that meets important societal information needs. The following trends will influence USGS geography-oriented science activities over the next decade. Most of the emerging earth science issues that the USGS will address are geographic phenomena. A growing international concern for aligning society’s development activities with environmental limits has led to an articulation of a science agenda associated with global environmental change, vulnerability, and resilience. Earth science investigations have evolved toward the study of very large areas, and the resulting huge volumes of data are challenging to manage and understand. Finally, scientists and the public face the challenge of gaining intelligent insights about geographic and environmental processes from these data, with the ultimate goal of guiding resource-management decisions. The first four science goals in the plan support understanding the human and environmental dynamics of land change. Each science goal has an associated set of strategic actions to achieve the goal. These goals and actions are consistent with national science priorities and the Department of Interior and USGS missions, take advantage of existing expertise, and lead to the strengthening of critical geographic research capacities that do not exist in other USGS disciplines.

Circular↗
USGS2007

Understanding knowledge and perceptions of bats among residents of Fort Collins, Colorado

As regional urbanization increases in Colorado, so do interactions between humans and wildlife. Where previous habitat has been reduced due to urbanization and development, a few bat species that easily adapt to new environments now roost in homes and buildings (Kunz and Reynolds, 2003). Bats frequently serve as reservoirs of disease that have potential health consequences for humans and other mammals (Messenger and others, 2003). As bat use of buildings becomes more frequent, the incidences of bat/human contact and the risk of spreading disease also increase. In Colorado, rabies is most common in the big brown bat (Eptesicus fuscus) Pape and others, 1999), the most ubiquitous species of urban-dwelling bat in the United States (Barbour and Davis, 1969) and the most common species submitted for rabies testing in Colorado (Pape and others, 1999). An in-depth knowledge of the big brown bat - including its ecology, habitat and movements, and aspects of disease transmission - and of its interactions with humans is essential for making informed management decisions regarding this species. To balance the competing priorities of species preservation and public safety, natural resource managers and public health professionals must be able to accurately estimate citizens' knowledge, perceptions, and perceived risks regarding the bat species that use human dwellings and harbor diseases potentially dangerous to humans. A recently completed five-year ecological study (2001-2005) on bats inhabiting buildings in Fort Collins, Colo., has provided much information on the basic epidemiology of rabies and on the ecology of the local bat population (Davis, Rudd, and Bowen, 2007; Ellison and others, 2007; Neubaum, Douglas, and others, in press; Neubaum, O'Shea, and Wilson, 2006; Neubaum, Wilson, and O'Shea, 2007; O'Shea, Ellison, and Stanley, 2004; Pearce and O'Shea, 2007; Pearce and others, in press; Shankar and others, 2004; Shankar and others, 2005; Wimsatt and others 2005). Research investigating the human dimensions of bats and bat/rabies relationships, however, has been very limited (Gibbins and others, 2002; Liesener and others, 2006). Herein, we report the results of a study to evaluate perceptions and knowledge of bats and rabies among residents of Fort Collins, Colo. The study resulted from collaborations between U.S. Geological Survey (USGS) bat ecologists of the Trust Species and Habitats branch, and social scientists of the Policy Analysis and Science Assistance branch, both of the USGS Fort Collins Science Center (FORT).

Open-File Report↗
USGS2023

Large increases in methane emissions expected from North America’s largest wetland complex

Natural methane (CH 4 ) emissions from aquatic ecosystems may rise because of human-induced climate warming, although the magnitude of increase is highly uncertain. Using an exceptionally large CH 4 flux dataset (~19,000 chamber measurements) and remotely sensed information, we modeled plot- and landscape-scale wetland CH 4 emissions from the Prairie Pothole Region (PPR), North America’s largest wetland complex. Plot-scale CH 4 emissions were driven by hydrology, temperature, vegetation, and wetland size. Historically, landscape-scale PPR wetland CH 4 emissions were largely dependent on total wetland extent. However, regardless of future wetland extent, PPR CH 4 emissions are predicted to increase by two- or threefold by 2100 under moderate or severe warming scenarios, respectively. Our findings suggest that international efforts to decrease atmospheric CH 4 concentrations should jointly account for anthropogenic and natural emissions to maintain climate mitigation targets to the end of the century.

North Dakota↗
USGS2006

Stability of low levels of perchlorate in drinking water and natural water samples

Perchlorate ion (ClO4-) is an environmental contaminant of growing concern due to its potential human health effects, impact on aquatic and land animals, and widespread occurrence throughout the United States. The determination of perchlorate cannot normally be carried out in the field. As such, water samples for perchlorate analysis are often shipped to a central laboratory, where they may be stored for a significant period before analysis. The stability of perchlorate ion in various types of commonly encountered water samples has not been generally examined-the effect of such storage is thus not known. In the present study, the long-term stability of perchlorate ion in deionized water, tap water, ground water, and surface water was examined. Sample sets containing approximately 1000, 100, 1.0, and 0.5 ??g l-1 perchlorate ion in deionized water and also in local tap water were formulated. These samples were analyzed by ion chromatography for perchlorate ion concentration against freshly prepared standards every 24 h for the first 7 days, biweekly for the next 4 weeks, and periodically after that for a total of 400 or 610 days for the two lowest concentrations and a total of 428 or 638 days for the high concentrations. Ground and surface water samples containing perchlorate were collected, held and analyzed for perchlorate concentration periodically over at least 360 days. All samples except for the surface water samples were found to be stable for the duration of the study, allowing for holding times of at least 300 days for ground water samples and at least 90 days for surface water samples. ?? 2006 Elsevier B.V. All rights reserved.

Analytica Chimica Acta↗
USGS1998

Evaluating landscape health: Integrating societal goals and biophysical process

Evaluating landscape change requires the integration of the social and natural sciences. The social sciences contribute to articulating societal values that govern landscape change, while the natural sciences contribute to understanding the biophysical processes that are influenced by human activity and result in ecological change. Building upon Aldo Leopold's criteria for landscape health, the roles of societal values and biophysical processes in shaping the landscape are explored. A framework is developed for indicators of landscape health and integrity. Indicators of integrity are useful in measuring biological condition relative to the condition in landscapes largely unaffected by human activity, while indicators of health are useful in evaluating changes in highly modified landscapes. Integrating societal goals and biophysical processes requires identification of ecological services to be sustained within a given landscape. It also requires the proper choice of temporal and spatial scales. Societal values are based upon inter-generational concerns at regional scales (e.g. soil and ground water quality). Assessing the health and integrity of the environment at the landscape scale over a period of decades best integrates societal values with underlying biophysical processes. These principles are illustrated in two contrasting case studies: (1) the South Platte River study demonstrates the role of complex biophysical processes acting at a distance; and (2) the Kissimmee River study illustrates the critical importance of social, cultural and economic concerns in the design of remedial action plans. In both studies, however, interactions between the social and the biophysical governed the landscape outcomes. The legacy of evolution and the legacy of culture requires integration for the purpose of effectively coping with environmental change.

Journal of Environmental Management↗
USGS2019

Emerging investigator series: Atmospheric cycling of indium in the northeastern United States

Indium is critical to the global economy and is used in an increasing number of electronics and new energy technologies. However, little is known about its environmental behavior or impacts, including its concentrations or cycling in the atmosphere. This study determined indium concentrations in air particulate matter at five locations across the northeastern United States over the course of one year, in 1995. Historical records from a Massachusetts bog core showed that indium atmospheric concentrations in this region changed only modestly between 1995 and 2010. Atmospheric indium concentrations varied significantly both geographically and temporally, with average concentrations in PM 3 of 2.1 ± 1.6 pg m −3 (1 standard deviation), and average particle-normalized concentrations of 0.2 ± 0.2 μg In per g PM 3 . Peaks in the particle-normalized concentrations in two New York sites were correlated with wind direction; air coming from the north contributed higher concentrations of indium than air coming from the west. This correlation, along with measurements of indium in zinc smelter emissions and coal fly ash, suggests that indium in the atmosphere in the northeastern United States comes from a relatively constant low-level input from coal combustion in the midwest, and higher but more sporadic contributions from the smelting of lead, zinc, copper, tin, and nickel north of the New York sample sites. Understanding the industrial sources of indium to the atmosphere and how they compare with natural sources can lead to a better understanding of the impact of human activities on the indium cycle, and may help to establish a baseline for monitoring future impacts as indium use grows.

Massachusetts, New York↗
USGS2021

Who’s your daddy? On the identity and distribution of the paternal hybrid ancestor of the parthenogenetic gecko Lepidodactylus lugubris (Reptilia: Squamata: Gekkonidae)

The widespread parthenogenetic gecko Lepidodactylus lugubris is comprised of several clonal lineages, at least one of which has been known for some time to have originated from hybridization between its maternal ancestor, Lepidodactylus moestus , and a putatively undescribed paternal ancestor previously known only from remote islands in the Central Pacific. By integrating new genetic sequences from multiple studies on Lepidodactylus and incorporating new genetic sequences from previously sampled populations, we recovered a phylogenetic tree that shows a close genetic similarity between the generally hypothesized paternal hybrid ancestor and a recently described species from Maluku (Indonesia), Lepidodactylus pantai . Our results suggest that the paternal hybrid ancestor of at least one parthenogenetic clone of L. lugubris is conspecific with L. pantai and that the range of this species extends to Palau, the Caroline Islands, the Kei Islands, Wagabu, and potentially other small islands near New Guinea. Deeper genetic structure in the western (Palau, Maluku) versus eastern (eastern Melanesia, Micronesia, Polynesia) part of this species’ range suggests that the western populations likely dispersed via natural colonization, whereas the eastern populations may be the result of human-mediated dispersal. The potential taxonomic affinities and biogeographic history should be confirmed with further morphological and genetic analyses, including research on L. woodfordi from its type locality, which would have nomenclatural priority if found to be conspecific with L. pantai . We recommend referring to the wide-ranging sexual species as Lepidodactylus pantai until such a comparison can be made.

Zootaxa↗