SEARCH · Geology Reports

Results for “Environmental Conservation”

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

SourceResearch connectionFrom yearThrough year

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

At least 1,477 records · Page 82Linked to original sources

USGS2018

Deciphering the link between doubly uniparental inheritance of mtDNA and sex determination in bivalves: Clues from comparative transcriptomics

Bivalves exhibit an astonishing diversity of sexual systems and sex-determining mechanisms. They can be gonochoric, hermaphroditic or androgenetic, with both genetic and environmental factors known to determine or influence sex. One unique sex-determining system involving the mitochondrial genome has also been hypothesized to exist in bivalves with doubly uniparental inheritance (DUI) of mtDNA. However, the link between DUI and sex determination remains obscure. In this study, we performed a comparative gonad transcriptomics analysis for two DUI-possessing freshwater mussel species to better understand the mechanisms underlying sex determination and DUI in these bivalves. We used a BLAST reciprocal analysis to identify orthologs between Venustaconcha ellipsiformis and Utterbackia peninsularis and compared our results with previously published sex-specific bivalve transcriptomes to identify conserved sex-determining genes. We also compared our data with other DUI species to identify candidate genes possibly involved in the regulation of DUI. A total of ∼12,000 orthologous relationships were found, with 2,583 genes differentially expressed in both species. Among these genes, key sex-determining factors previously reported in vertebrates and in bivalves (e.g., Sry, Dmrt1, Foxl2 ) were identified, suggesting that some steps of the sex-determination pathway may be deeply conserved in metazoans. Our results also support the hypothesis that a modified ubiquitination mechanism could be responsible for the retention of the paternal mtDNA in male bivalves, and revealed that DNA methylation could also be involved in the regulation of DUI. Globally, our results suggest that sets of genes associated with sex determination and DUI are similar in distantly-related DUI species.

Genome Biology and Evolution↗

USGS2022

A statistical framework for modelling migration corridors

1. Management of animal populations requires spatially explicit knowledge of movement corridors, such as those used during seasonal migrations. GPS tracking data allows for mapping of corridors from directly observed movements, providing important insights, but tracking data is absent for many populations. 2. We developed a novel statistical corridor modeling approach that predicts movement corridors from cost-distance movement models fit directly to migration tracking data. Unlike existing predictive approaches, this does not require the ad-hoc transformation of habitat suitability surfaces into resistance surfaces. We tested the ability of the approach to recover parameters used to generate simulated movements. We then used GPS data from three migrating mule deer (Odocoileus hemionus) herds in Idaho and Wyoming to model corridors as a function of elevation, slope, aspect, percent shrub, date of peak green-up, snow-off date, and human footprint. We assessed the predictive ability of the fitted models using validation tracks from the same herd as well as from the other herds. 3. The approach reproduced parameters used to generate the simulated movements, predicted the corridors used by migratory populations, and described the direction, magnitude, and confidence levels of the effects of environmental variables on corridors. The effects environmental variables had on corridors differed depending on the herd. Within-herd validation indicated that fitted corridor models are more accurate at predicting migration corridors than null models, and cross-herd validation indicated that fitted models for some herds accurately predicted the observed migrations of other herds. 4. In addition to the practical benefit of mapping corridors for management, our statistical corridor modeling framework sets the stage for evaluating fundamental questions about the fitness tradeoffs, navigation, learning, fidelity, and movement constraints that influence migratory and other corridor-generating behavior. Models of predictive corridors can inform management and planning for the conservation of migrations across taxa, including the potential restoration of corridors. Our corridor modeling approach is also readily applied to non-migratory animal movements.

Idaho, Wyoming↗

USGS2019

Climate vulnerability assessment for Pacific salmon and steelhead in the California Current Large Marine Ecosystem

Major ecological realignments are already occurring in response to climate change. To be successful, conservation strategies now need to account for geographical patterns in traits sensitive to climate change, as well as climate threats to species-level diversity. As part of an effort to provide such information, we conducted a climate vulnerability assessment that included all Pacific salmon and steelhead (Oncorhynchus spp.) listed under the U.S. Endangered Species Act. Using an expert-based scoring system, we ranked 20 attributes for the 28 listed units, and 5 additional units. Attributes captured biological sensitivity, or the strength of linkages between each listing unit and the present climate; climate exposure, or the magnitude of projected change in local environmental conditions; and adaptive capacity, or the ability to modify phenotypes to cope with new climatic conditions. Each listing unit was then assigned one of four vulnerability categories.

California↗

USGS2025

Using structural causal modeling to infer the effects of wildfire on foothill yellow-legged frog occurrence

Sierra Nevada ecosystems have been influenced by fire for millennia; however, increasing wildfire size and frequency may yield unforeseen consequences on wildlife populations and their distribution. Foothill yellow-legged frogs Rana boylii have declined in portions of their range and are considered a species of conservation concern. We surveyed streams for foothill yellow legged frogs in and near the 2021 Dixie Fire footprint using double-observer visual encounter surveys that incorporated time-to-detection methods, and used structural causal modeling to improve post-fire inference while lacking pre-fire data. We found that foothill yellow-legged frog probability of occurrence was 4.93 (95% equal-tailed interval = 0.52 – 160) times higher outside the footprint of the Dixie Fire than within it, though probability of occurrence was generally low within our sampling frame (ψ unburned = 0.21 [0.08 – 0.49]; ψ burned = 0.05 [0.002 – 0.28]). Measured environmental characteristics, however, were similar within and outside the fire footprint, and observed occupancy patterns might reflect the recent historical distribution of the frogs. Our study emphasizes the importance of site-specific pre-disturbance data when attempting to evaluate the causal effects of disturbances on wildlife. Although it remains to be seen how this species will fare in an increasingly frequent and intense fire regime, foothill yellow-legged frogs may tolerate some level of fire disturbance.

California↗

USGS2023

Does post-fire recovery of native grasses across abiotic-stress and invasive-grass gradients match theoretical predictions, in sagebrush steppe?

Interactions among species can strongly affect how plant communities reassemble after disturbances, and variability among native and invasive species across environmental gradients must be known in order to manage plant-community recovery. The stress-gradient hypothesis (SGH) predicts species interactions will be more positive in abiotically stressful conditions and conversely, more negative in benign conditions, and the resistance-resilience concept (RRC) may predict where and when invasions will complicate ecosystem recovery. We evaluated how abiotic stress and biotic interactions determine native bunchgrass abundances across environmental gradients using additive models of cover data from over 500 plots re-measured annually for 5 years as they recovered naturally (untreated) after a megafire (>100,000 ha) in sagebrush steppe threated by the invasive-grass and fire cycle. The species included native bunchgrasses, bluebunch wheatgrass ( Pseudoroegneria spicata ) and Sandberg bluegrass ( Poa secunda ), and the exotic and invasive annual cheatgrass ( Bromus tectorum ). We asked whether associations between native bunchgrasses and cheatgrass were context dependent and if the SGH could help predict interspecific associations between species in a semiarid environment. The association of cover of each native bunchgrass to cheatgrass was not uniform, and instead varied from neutral to negative across environmental gradients in both space and time (i.e., weather), to which the species had nonlinear and sometimes threshold-like responses. Consistent with the SGH, bunchgrasses were generally more negatively related to cheatgrass (i.e., putative competition) in conditions which increased the cover of each bunchgrass – which were higher elevations and temperatures and lower solar heatload, and, for Sandberg bluegrass, drier conditions. There were few indications of positive interactions (i.e., putative facilitation) in stressful conditions, and instead associations were again negative, albeit weaker, in some of the conditions evaluated. Synthesis . These findings demonstrate that the negative association among native bunchgrasses and cheatgrass is context dependent and is determined by the abundances of both interacting species which is driven by environmental stress. This led to a hypothesis that together Sandberg bluegrass and bluebunch wheatgrass provide complementary resistance to cheatgrass at the landscape level, despite their different ecology and contrary to the management preference for bluebunch wheatgrass. Sandberg bluegrass might be critical for providing resistance against cheatgrass where invasion potential is greatest, i.e., at lower elevations, where bluebunch wheatgrass is scarce.

Global Ecology and Conservation↗

USGS2024

Concordant signal of genetic variation across marker densities in the desert annual Chylismia brevipes is linked with timing of winter precipitation

Climate change coupled with large-scale surface disturbances necessitate active restoration strategies to promote resilient and genetically diverse native plant communities. However, scarcity of native plant materials hinders restoration efforts, leading practitioners to choose from potentially viable but nonlocal seed sources. Genome scans for genetic variation linked with selective environmental gradients have become a useful tool in such efforts, allowing rapid delineation of seed transfer zones along with predictions of genomic vulnerability to climate change. When properly applied, genome scans can reduce the risk of maladaptation due to mismatches between seed source and planting site. However, results are rarely replicated among complimentary data sources. Here, we compared RAD-seq datasets with 819 and 2699 SNPs (in 625 and 356 individuals, respectively) from the Mojave Desert winter annual Chylismia brevipes . Overall, we found that the datasets consistently characterized both neutral population structure and genetic–environmental associations. Ancestry analyses indicated consistent spatial genetic structuring into four regional populations. We also detected a marked signal of isolation by resistance (IBR), wherein spatial genetic structure was better explained by habitat resistance than by geographic distance. Potentially adaptive loci identified from genome scans were associated with the same environmental gradients—fall precipitation, winter minimum temperature, and precipitation timing—regardless of dataset. Paired with our finding that habitat resistance best explained genetic divergence, our results suggest that isolation of populations within environmentally similar habitats—and subsequent local adaption along gradients parallel to these habitats—drive genome-wide divergence in this species. Moreover, strong genetic associations with winter precipitation timing, along with forecasted shifts in precipitation regime due to midcentury climate change, could impact future population dynamics, habitat distribution, and genetic connectivity for C. brevipes populations within the Mojave Desert.

Arizona, California, Nevada↗

USGS1993

Dissimilatory Fe(III) reduction by the marine microorganism Desulfuromonas acetoxidans

The ability of the marine microorganism Desulfuromonas acetoxidans to reduce Fe(III) was investigated because of its close phylogenetic relationship with the freshwater dissimilatory Fe(III) reducer Geobacter metallireducens. Washed cell suspensions of the type strain of D. acetoxidans reduced soluble Fe(III)-citrate and Fe(III) complexed with nitriloacetic acid. The c -type cytochrome(s) of D. acetoxidans was oxidized by Fe(III)-citrate and Mn(IV)-oxalate, as well as by two electron acceptors known to support growth, colloidal sulfur and malate. D. acetoxidans grew in defined anoxic, bicarbonate-buffered medium with acetate as the sole electron donor and poorly crystalline Fe(III) or Mn(IV) as the sole electron acceptor. Magnetite (Fe 3 O 4 ) and siderite (FeCO 3 ) were the major end products of Fe(III) reduction, whereas rhodochrosite (MnCO 3 ) was the end product of Mn(IV) reduction. Ethanol, propanol, pyruvate, and butanol also served as electron donors for Fe(III) reduction. In contrast to D. acetoxidans, G. metallireducens could only grow in freshwater medium and it did not conserve energy to support growth from colloidal S 0 reduction. D. acetoxidans is the first marine microorganism shown to conserve energy to support growth by coupling the complete oxidation of organic compounds to the reduction of Fe(III) or Mn(IV). Thus, D. acetoxidans provides a model enzymatic mechanism for Fe(III) or Mn(IV) oxidation of organic compounds in marine and estuarine sediments. These findings demonstrate that 16S rRNA phylogenetic analyses can suggest previously unrecognized metabolic capabilities of microorganisms.

Applied and Environmental Microbiology↗

USGS2000

Ground-water conditions in Georgia, 1999

Ground-water conditions in Georgia during 1999 and for the period of record were evaluated using data from U.S. Geological Survey ground-water-level and ground-water-quality monitoring networks. Data for 1999 included in this report are from continuous water-level records from 130 wells and chloride analyses from 14 wells. Data from one well is incomplete because data collection was discontinued. Chloride concentration in water from the Upper Floridan aquifer in most of coastal Georgia was within drinking-water standards established by the Georgia Department of Natural Resources and the U.S. Environmental Protection Agency. In the Savannah area, chloride concentration has not changed appreciably with time. However, chloride concentration in water from some wells that tap the Floridan aquifer system in the Brunswick area exceeds the drinking-water standards. Ground-water-level and ground-water-quality data are essential for water assessment and management. Ground-water-level fluctuations and trends can be used to estimate changes in aquifer storage resulting from the effects of ground-water withdrawal and recharge from precipitation. These data can be used to address water-management needs and to evaluate the effects of management and conservation programs. As part of the ground-water investigations conducted by the U.S. Geological Survey (USGS), in cooperation with the State of Georgia and city and county governments, a Statewide water-level-measurement program was started in 1938. Initially, this program consisted of an observation-well network in the coastal area of Georgia to monitor variations in ground-water storage and quality. Additional wells were later included in areas where data could be used to aid in water resources development and management. During 1999, periodic water-level measurements were made in 46 wells, and continuous water-level measurements were obtained from 165 wells. Continuous water-level records were obtained using analog (pen and chart) recorders and electronic data recorders that record the water level at 60-minute intervals. For wells having incomplete water-level record, water levels during periods of missing record may have been higher or lower than recorded water levels. Water samples collected from 85 wells during May, June, July, August, September, October, November, and December 1999 were analyzed to determine chloride concentration in the Savannah and Brunswick areas.

Georgia↗

USGS1998

Ground-water conditions in Georgia, 1997

Ground-water conditions in Georgia during 1997 and for the period of record were evaluated using data from ground-water-level and ground-water-quality monitoring networks. Data for 1997 included in this report are from continuous water-level records from 71 wells and chloride analyses from 14 wells. In 1997, annual mean ground-water levels in Georgia ranged from 6.2 feet (ft) lower to 5.6 ft higher than in 1996. Of the 71 wells summarized in this report, 23 wells had annual mean water levels that were higher, 35 wells had annual mean water levels that were lower, and 11 wells had annual mean water levels that were about the same in 1997 as during 1996. Data for two wells are incomplete because data collection was discontinued at one well, and the equipment was vandalized at one well. Record-low daily mean water levels were recorded in six wells tapping the Upper Floridan aquifer, one well tapping the Caliborne aquifer, two wells tapping the Clayton aquifer, and three wells tapping Cretaceous aquifers. These record lows were from 0.2 to 5.6 ft lower than previous record lows. Chloride concentration in water from the Upper Floridan aquifer in most of coastal Georgia was within drinking-water standards established by the Georgia Department of Natural Resources and the U.S. Environmental Protection Agency. In the Savannah area, chloride concentration has not changed appreciably with time. However, chloride concentration in water from some wells that tap the Floridan aquifer system in the Brunswick area exceeds the drinking-water standard. Ground-water-level and ground-water-quality data are essential for water assessment and management. Ground-water-level fluctuations and trends can be used to estimate changes in aquifer storage resulting from the effects of ground-water withdrawal and recharge from precipitation. These data can be used to address water-management needs and to evaluate the effects of management and conservation programs. As part of the ground-water investigations conducted by the U.S. Geological Survey (USGS), in cooperation with the State of Georgia and city and county governments, a Statewide water-level- measurement program was started in 1938. Initially, this program consisted of an observation-well network in the coastal area of Georgia to monitor variations in ground- water storage and quality. Additional wells were later included in areas where data could be used to predict potential water-resource problems. During 1997, periodic water-level measurements were made in 67 wells, and continuous water-level measurements were obtained from 151 wells. Continuous water-level records were obtained using analog (pen and chart) recorders, digital recorders that record the water level at 30-minute or 60-minute intervals, and electronic data recorders that record the water level at 60-minute intervals. For wells having incomplete water-level record, water levels during periods of missing record may have been higher or lower than recorded water levels. Water samples collected from 23 wells during April and November 1997 were analyzed to determine chloride concentration in the Savannah and Brunswick areas.

Georgia↗

USGS2014

Status and trends of Caribbean coral reefs: 1970-2012

This it the 9th status report since the Global Coral Reef Monitoring Network (GCRMN) was founded in 1995 was the data arm of the International Coral Reef Initiative (ICRI) to document the ecological condition or corral reefs, strengthen monitoring efforts, and link existing organizations and people working on reefs worldwide. The US Government provided the initial funding to help set up a global network of coral reef workers and has continued to provide core support. Since then, the series of reports have aimed to present the current status of coral reefs of the world or particular regions, the major threats to reefs and their consequences, and any initiative undertaken under the auspices of ICRI or other bodies to arrest or reverse the decline of coral reefs. IUCN assumed responsibility for hosting the global coordination of the GCRMN in 2010 under the scientific direction of Jeremy Jackson with the following objectives: 1. Document quantitatively the global status and trends for corals, macroalgae, sea urchins, and fishes based on available data from individual scientists as well as the peer reviewed scientific literature, monitoring programs, and report. 2. Bring together regional experts in a series of workshops to involve them in data compilation, analysis, and synthesis. 3. Integrate coral reef status and trends with independent environmental, management, and socioeconomic data to better understand the primary factors responsible for coral reef decline, the possible synergies among factors that may further magnify their impacts, and how these stresses may be more effectively alleviated. Work with GCRMN partners to establish simple and practical standardized protocols for future monitoring and assessment. Disseminate information and results to help guide member state policy and actions. The overarching objective is to understand why some reefs are much healthier than others, to identify what kinds of actions have been particularly beneficial or harmful, and to vigorously communicate results in simple and straightforward terms to foster more effective conservation and management. This and subsequent reports will focus on separate biogeographic regions in a stepwise fashion and combine all of the results for a global synthesis in the coming years. We began in the wide Caribbean region because the historical data are so extensive and to refine methods of analysis before moving on to other regions. This report documents quantitative trends for Caribbean reef corals, macroalgae, sea urchins, and fishes based on data from 90 reef locations over the past 43 tears. This is the first report to combine all these disparate kinds of data in a single place to explore how the different major components of coral reef ecosystems interact on a broadly regional oceanic scale. We obtained data from more than 35,000 ecological surveys carried out by 78 principal investigators (PIs) and some 200 colleagues working in 34 countries, states, and territories throughout the wide Caribbean region. We conducted two workshops in Panama and Brisbane, Australia to bring together people who provided the data to assist in data quality control, analysis, and synthesis. The first workshop at the Smithsonian Tropical Research Institute (STRI) in the Republic of Panama 29 April to 5 May, 2012 included scientists from 18 countries and territories to verify and expand the database and to conduct exploratory analyses of status and trends. Preliminary results based on the Panama workshop were presented to the DC Marine Community and Smithsonian Institution Senate of Scientists in May 2012 and at the International Coral Reef Symposium (ICRS) and annual ICRI meeting in Cairns, Australia in July 2012. The second workshop in Brisbane, Australia in December 2012 brought together eight coral reef scientists for more detailed data analysis and organization of results for this report and subsequent publications. Subsequent presentations to solicit comments while the report was being finalized were made in 2013-2014 at the ICRI General meeting in Belize, the biennial meeting of the Association of Island Marine Laboratories in Jamaica, the Panamerican Coral Reef Congress in Merida, Mexico, the annual meeting of he Western Society of Naturalists, and numerous universities in Costa Rica, the USA and Europe. The main body of the report is in two sections. Part I provides an overview of overall status and trends and detailed analyses of the multiple factors responsible for the decline of reef corals throughout the entire wider Caribbean region. The editors are grateful to all the people who have so generously provided data and expertise, but we assume responsibility for the many statements, conclusions and recommendations and final wording of the text. Part II provides a more detailed analysis of the status and trends of coral reef ecosystems in the 32 countries, states, and territories for which we have data. The format includes maps indicating all locations sampled, a detailed table of data sources and sites surveyed, timelines of ecologically important evens, and relevant references. Each of these reports was compiled in consultation with local experts and all those who provided data and advice are listed as authors of each country report.

Report↗

USGS2024

Intrinsic and environmental drivers of pairwise cohesion in wild Canis social groups

Animals within social groups respond to costs and benefits of sociality by adjusting the proportion of time they spend in close proximity to other individuals in the group (cohesion). Variation in cohesion between individuals, in turn, shapes important group-level processes such as subgroup formation and fission–fusion dynamics. Although critical to animal sociality, a comprehensive understanding of the factors influencing cohesion remains a gap in our knowledge of cooperative behavior in animals. We tracked 574 individuals from six species within the genus Canis in 15 countries on four continents with GPS telemetry to estimate the time that pairs of individuals within social groups spent in close proximity and test hypotheses regarding drivers of cohesion. Pairs of social canids ( Canis spp.) varied widely in the proportion of time they spent together (5%–100%) during seasonal monitoring periods relative to both intrinsic characteristics and environmental conditions. The majority of our data came from three species of wolves (gray wolves, eastern wolves, and red wolves) and coyotes. For these species, cohesion within social groups was greatest between breeding pairs and varied seasonally as the nature of cooperative activities changed relative to annual life history patterns. Across species, wolves were more cohesive than coyotes. For wolves, pairs were less cohesive in larger groups, and when suitable, small prey was present reflecting the constraints of food resources and intragroup competition on social associations. Pair cohesion in wolves declined with increased anthropogenic modification of the landscape and greater climatic variability, underscoring challenges for conserving social top predators in a changing world. We show that pairwise cohesion in social groups varies strongly both within and across Canis species, as individuals respond to changing ecological context defined by resources, competition, and anthropogenic disturbance. Our work highlights that cohesion is a highly plastic component of animal sociality that holds significant promise for elucidating ecological and evolutionary mechanisms underlying cooperative behavior.

Ecology↗

USGS2023

Per- and polyfluoroalkyl substances in groundwater from the Great Miami buried-valley aquifer, southwestern Ohio, 2019–20

Groundwater samples were collected during 2019 and 2020 from 23 wells in the Great Miami buried-valley aquifer (GM-BVA) in southwestern Ohio by the U.S. Geological Survey, in cooperation with the Miami Conservancy District, Dayton, Ohio, to determine concentrations of selected per- and polyfluoroalkyl substances (PFAS). The GM-BVA is a glacial outwash and alluvial fill aquifer that is the sole source of water supply for much of the region. Wells had total depths that ranged from 21 to 101 feet below land surface, and groundwater levels that ranged from 1.39 to 52.15 feet below land surface before sampling in 2019. Groundwater and related quality-control samples were sequentially collected from 22 of the 23 wells and analyzed for 24 different PFAS by 2 methods that used proprietary isotope-dilution based adaptations of U.S. Environmental Protection Agency (EPA) method 537.1, termed methods 1 and 2. Method 2 had smaller reporting limits (RL) for 22 of 24 PFAS analyzed and smaller detection limits (DLs) for all 24 PFAS analyzed compared with method 1, which made method 2 more sensitive to detect PFAS. Concentrations of perfluorooctanesulfonate (PFOS) in a groundwater (GW)-method 2 sample from well CL–275 of 1.9 nanograms per liter (ng/L) and perfluorooctanoate (PFOA) in a GW-method 2 sample from well BU–1106 of 2.1 ng/L were greater than their EPA interim health advisory guidances for drinking water (as of June 2022) by about 9,500 and 52,500 percent, respectively. The EPA interim health advisory guidances for PFOS (0.02 ng/L) and PFOA (0.004 ng/L) were also 65 and 215 times less, respectively, than the smallest method 2 DLs for PFOS (1.3 ng/L) and PFOA (0.86 ng/L). Other PFAS were either not detected in GM-BVA groundwater samples or were detected in concentrations less than Ohio action levels or Federal health-risk-based guidance. The most detected PFAS in groundwater was perfluorobutanesulfonate (PFBS), which had concentrations in samples from eight wells that ranged from 1.0 to 8.0 ng/L or from 0.05 to 0.4 percent of its EPA health advisory of 2,000 ng/L for drinking water. The similarity of PFBS (7.8 ng/L), perfluoropentanesulfonate (PFPeS; 8.1 ng/L), and perfluorohexanesulfonate (PFHxS; 14 ng/L) concentrations yielded from the GW-method 1 sample from well CL–275 on July 9, 2019, to those of PFBS (8.0 ng/L), PFPeS (7.8 ng/L), and PFHxS (16 ng/L) from the paired GW-method 2 sample demonstrated the capability of both methods to reproduce PFAS concentrations that were greater than their respective DLs. Non-detection of these PFAS in follow-up GW-method 1 and sequential replicate (Rep–GW-method 1) samples from CL–275 on April 21, 2020, indicated that the 2019 results represented a transient detection in groundwater. Eleven of twenty-three wells sampled in 2019 had from 1 to 4 PFAS detected in one or more groundwater samples or in a paired replicate sample: PFBS in 8 wells and 9 samples; PFHxS in 4 wells and 5 samples; and PFPeS, PFOS, perfluorobutanoate, perfluoropentanoate, PFOA, and perfluorooctanesulfonamide in 1 well and 1 sample each. More PFAS were detected in GW-method 2 samples than GW-method 1 samples because method 2 had smaller RLs and DLs. Results indicate benefits from the analysis of paired samples, sequential replicate samples, and other quality-control samples using analytical methods with sensitive RLs and DLs to verify PFAS concentrations in groundwater. Groundwater-age estimates indicate that water produced from all sampled wells had infiltrated to the water table within the 1947–present (2022) period of PFAS use or environmental presence. Eight wells with detectable PFBS in groundwater from 2019 samples also had groundwater-recharge dates that ranged from 1991 to 2016. Those ages coincided with the possible environmental presence of PFBS as a PFAS byproduct or use as an alternative to PFOS after about 2002. Two wells that had detections of PFHxS in 2019 groundwater samples also had post-2000 groundwater-recharge dates that coincided with the period of use of PFHxS as an alternative to PFOS. Six of nine wells with more than 66-percent of urban land use that was within 0.3 miles of each well, as of 2012, also had 1 to 4 PFAS detected in one of their groundwater samples. Seven of nine wells that produced groundwater in 2019 with an oxic redox category also had one or more PFAS detected in a sample.

Ohio↗

USGS2019

Explaining harvests of wild-harvested herbaceous plants: American ginseng as a case study

Wild-harvested plants face increasing demand globally. As in many fisheries, monitoring the effect of harvesting on the size and trajectory of resource stocks presents many challenges given often limited data from disparate sources. Here we analyze American ginseng ( Panax quinquefolius L.) harvests from 18 states in the eastern U.S. 1978–2014 to infer temporal patterns and evidence of population declines, and we test the effects of local environmental and socioeconomic factors on ginseng harvesting at the county level 2000–2014. Despite rising prices, annual wild ginseng harvests decreased from a high point in the late 1980s to early 1990s, then, in most, increased after 2005 or 2010 - suggesting range-wide overexploitation notwithstanding federal regulations that, since 1999, restrict minimum harvest age. County-level harvest rates increased with available habitat, road density, poverty and unemployment, but decreased when public land formed a large proportion of county area. Harvests were largest in the Southern Appalachian region. Poverty and accessibility were strongly related to high levels of harvesting. A key implication is that to conserve valuable wild native plant products while also improving local livelihoods, wild cultivation and good stewardship practices must be strongly promoted. Our approach to assessing the condition of wild populations offers a broad template that could be adapted to other wild-harvested plants.

Biological Conservation↗

USGS2009

Landscape characteristics of fragmented shrubsteppe habitats and breeding passerine birds

We examined the influence of local and landscape-level attributes of fragmented habitats in shrubsteppe habitats on the breeding distributions of Sage ( Amphispiza belli ) and Brewer's ( Spizella breweri ) Sparrows, Sage Thrashers ( Oreoscoptes montanus ), Horned Larks ( Eremophila alpestris ), and Western Meadowlarks ( Sturnella neglecta ) in the Snake River Plains of southwestern Idaho. We developed habitat (resource) selection models for each species by combining bird counts conducted from 1991 through 1933 with local vegetation characteristics and landscape attributes derived from satellite imagery. Site selection by shrubsteppe species (Sage and Brewer's Sparrows, and Sage Thrashers) depended on local vegetation cover and landscape features, such as the patch size of shrub habitats or the spatial similarity of sites. Marginal sites for these species (with species present in one of three years) were intermediate between unoccupied (never present) and occupied sites along environmental gradients characterized by increasing size of shrub habitat patches and total shrub cover and by decreasing disturbance. Horned Larks and Western Meadowlarks, typical grassland species, were not sensitive to landscape features, and their occupancy depended on the amount of grassland or shrub cover. In contrast to shrubsteppe species, sites that varied by occupancy rates of Western Meadowlarks did not significantly differ in vegetation or landscape components. Our results demonstrate that fragmentation of shrubsteppe significantly influenced the presence of shrub-obligate species. Because of restoration difficulties, the disturbance of semiarid shrubsteppe may cause irreversible loss of habitat and significant long-term consequences for the conservation of shrub-obligate birds.

Idaho↗

USGS2013

The δ2H and δ18O of tap water from 349 sites in the United States and selected territories

Because the stable isotopic compositions of hydrogen (δ 2 H) and oxygen (δ 18 O) of animal (including human) tissues, such as hair, nail, and urine, reflect the δ 2 H and δ 18 O of water and food ingested by an animal or a human and because the δ 2 H and δ 18 O of environmental waters vary geographically, δ 2 H and δ 18 O values of tap water samples collected in 2007-2008 from 349 sites in the United States and three selected U.S. territories have been measured in support of forensic science applications, creating one of the largest databases of tap water δ 2 H and δ 18 O values to date. The results of replicate isotopic measurements for these tap water samples confirm that the expanded uncertainties (U = 2μ c ) obtained over a period of years by the Reston Stable Isotope Laboratory from δ 2 H and δ 18 O dual-inlet mass spectrometric measurements are conservative, at ±2‰ and ±0.2 ‰, respectively. These uncertainties are important because U.S. Geological Survey data may be needed for forensic science applications, including providing evidence in court cases. Half way through the investigation, an isotope-laser spectrometer was acquired, enabling comparison of dual-inlet isotope-ratio mass spectrometric results with isotope-laser spectrometric results. The uncertainty of the laser-based δ 2 H measurement results for these tap water samples is comparable to the uncertainty of the mass spectrometric method, with the laser-based method having a slightly lower uncertainty. However, the δ 18 O uncertainty of the laser-based method is more than a factor of ten higher than that of the dual-inlet isotoperatio mass spectrometric method.

Guam, Puerto Rico, St. John, U.S. Virgin Islands↗

USGS1998

Front Range Infrastructure Resources Project: water-resources activities

Infrastructure, such as roads, buildings, airports, and dams, is built and maintained by use of large quantities of natural resources such as aggregate (sand and gravel), energy, and water. As urban area expand, local sources of these resource are becoming inaccessible (gravel cannot be mined from under a subdivision, for example), or the cost of recovery of the resource becomes prohibitive (oil and gas drilling in urban areas is costly), or the resources may become unfit for some use (pollution of ground water may preclude its use as a water supply). Governmental land-use decision and environmental mandates can further preclude development of natural resources. If infrastructure resources are to remain economically available. current resource information must be available for use in well-reasoned decisions bout future land use. Ground water is an infrastructure resource that is present in shallow aquifers and deeper bedrock aquifers that underlie much of the 2,450-square-mile demonstration area of the Colorado Front Range Infrastructure Resources Project. In 1996, mapping of the area's ground-water resources was undertaken as a U.S. Geological Survey project in cooperation with the Colorado Department of Natural Resources, Division of Water Resources, and the Colorado Water Conservation Board.

Colorado↗

USGS2016

Preliminary investigation of groundwater flow and trichloroethene transport in the Surficial Aquifer System, Naval Industrial Reserve Ordnance Plant, Fridley, Minnesota

Industrial practices at the Naval Industrial Reserve Ordnance Plant, in Fridley, Minnesota, caused soil and groundwater contamination. Some volatile organic compounds from the plant might have discharged to the Mississippi River, forced by the natural hydraulic gradient in the surficial aquifer system. The U.S. Environmental Protection Agency included the Naval Industrial Reserve Ordnance Plant on the Superfund National Priorities List in 1989. This report describes a preliminary characterization of trichloroethene transport in the surficial and Cambrian-Ordovician aquifer systems at the Naval Industrial Reserve Ordnance Plant. The characterization first involved simulation of 2001 conditions using a model, followed by an application of this 2001 simulator to 2011 conditions. The U.S. Geological Survey, in cooperation with the U.S. Department of the Navy, used a steady-state, uniform-density groundwater flow model to simulate measured potentiometric heads in aquifer systems on August 20, 2001, and a single-phase, conservative, non-reactive, miscible transport model to simulate trichloroethene concentrations in aquifer systems measured in 2001. The U.S. Department of the Navy furnished trichloroethene source areas and trichloroethene source area concentrations to the U.S. Geological Survey for this model simulation. Furnished delineations were postulated and informed by data collected from 1995 to 2011. The groundwater flow simulation of August 20, 2001, was superior to the trichloroethene transport simulation at replicating measurements; simulated potentiometric heads matched 90 percent of measured potentiometric heads on August 20, within 2 feet at selected locations whereas simulated trichloroethene concentration contours of 3, 10, 100, 1000, and 10,000 micrograms per liter (µg/L) correctly bounded 52 percent of measured concentrations in 2001 at selected locations. The degree to which the simulated trichloroethene plume does not match trichloroethene measurements in the surficial aquifer system during the 2001 simulation may suggest that furnished trichloroethene source areas and trichloroethene source area concentrations did not accurately represent all trichloroethene sources in the hydrogeologic system. During the model simulation of 2001, trichloroethene discharged to the Mississippi River. A simulated 900-foot-long zone of benthic trichloroethene discharge flux existed in the shallow flow zone, across which simulated trichloroethene discharged from the surficial aquifer system to the Mississippi River at simulated trichloroethene concentrations that ranged from 3 µg/L to more than 100 µg/L. The Mississippi River was not sampled for volatile organic compounds in Fridley, Minn., from 1999 to 2016 (the publication of this report). Trichloroethene concentrations were measured in wells close to the Mississippi River in the surficial aquifer system on the downgradient side of the Naval Industrial Reserve Ordnance Plant groundwater flow field; for example, at well MS–43 in the shallow flow zone of the surficial aquifer system 280 feet east of the Mississippi River between December 1999 and August 2012, trichloroethene concentrations ranged from 130 to 220 µg/L. The 220-µg/L maximum concentration was reached in March 2003 and October 2006. The August 2012 concentration was 140 µg/L. The August 20, 2001, groundwater flow model simulator and the 2001 trichloroethene transport simulator were applied to a groundwater extraction and treatment system that existed in 2011. Furnished trichloroethene source areas and concentrations in the 2001 simulator were replaced with different, furnished, hypothetical source areas and concentrations. Forcing in 2001 was replaced with forcing in 2011. No trichloroethene concentrations greater than 3 µg/L were simulated as discharging to the Mississippi River during applications of the 2001 simulator to the 2011 groundwater extraction and treatment system. These applications were not intended to represent historical conditions. Differences between furnished and actual trichloroethene sources may explain differences between measurements and simulation results for the 2001 trichloroethene transport simulator. Causes of differences between furnished and actual trichloroethene sources may cause differences between hypothetical application results and the performance of the actual U.S. Department of the Navy groundwater extraction and treatment system at the Naval Industrial Reserve Ordnance Plant. Other limitations may also cause differences between application results and performance.

Minnesota↗

USGS2006

Sources and occurrence of chloroform and other trihalomethanes in drinking-water supply wells in the United States, 1986-2001

Chloroform and three other trihalomethanes (THMs)--bromodichloromethane, dibromochloromethane, and bromoform--are disinfection by-products commonly produced during the chlorination of water and wastewater. Samples of untreated ground water from drinking-water supply wells (1,096 public and 2,400 domestic wells) were analyzed for THMs and other volatile organic compounds (VOCs) during 1986-2001, or compiled, as part of the U.S. Geological Survey's National Water-Quality Assessment Program. This report provides a summary of potential sources of THMs and of the occurrence and geographical distribution of THMs in samples from public and domestic wells. Evidence for an anthropogenic source of THMs and implications for future research also are presented. Potential sources of THMs to both public and domestic wells include the discharge of chlorinated drinking water and wastewater that may be intentional or inadvertent. Intentional discharge includes the use of municipally supplied chlorinated water to irrigate lawns, golf courses, parks, gardens, and other areas; the use of septic systems; or the regulated discharge of chlorinated wastewater to surface waters or ground-water recharge facilities. Inadvertent discharge includes leakage of chlorinated water from swimming pools, spas, or distribution systems for drinking water or wastewater sewers. Statistical analyses indicate that population density, the percentage of urban land, and the number of Resource Conservation and Recovery Act hazardous-waste facilities near sampled wells are significantly associated with the probability of detection of chloroform, especially for public wells. Domestic wells may have several other sources of THMs, including the practice of well disinfection through shock chlorination, laundry wastewater containing bleach, and septic system effluent. Chloroform was the most frequently detected VOC in samples from drinking-water supply wells (public and domestic wells) in the United States. Although chloroform was detected frequently in samples from public and domestic wells and the other THMs were detected in some samples, no concentrations in samples from either well type exceeded the U.S. Environmental Protection Agency's Maximum Contaminant Level of 80 micrograms per liter for total THMs. Chloroform was detected in public well samples almost twice as frequently (11 percent) as in domestic well samples (5 percent). The other three THMs also were detected more frequently in public well samples than in domestic well samples. This detection pattern may be attributed to public wells having a higher pumping capacity than domestic wells. The higher capacity wells create a larger capture zone that potentially intercepts more urban and other land uses and associated point and nonpoint sources of contamination than the smaller capacity domestic wells. THM detection frequencies in domestic well samples show a pattern of decreasing frequency with increasing bromide content, that is in the order: chloroform > bromodichloromethane >= dibromochloromethane >= bromoform. This same pattern has been documented in studies of water chlorination, indicating that an important source of chloroform and other THMs in drinking-water supply wells may be the recycling of chlorinated water and wastewater. Mixtures of THMs commonly occur in public well samples, and the most frequently occurring are combinations of the brominated THMs. These THMs have limited industrial production, few natural sources, and small or no reported direct releases to the environment. Therefore, industrial, commercial, or natural sources are not likely sources of the brominated THMs in public and domestic well samples. The THM detection frequency pattern, the co-occurrence of brominated THMs, and other lines of evidence indicate that the recycling of water with a history of chlorination is an important source of these compounds in samples from drinking-water supply wells.

Scientific Investigations Report↗