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USGS2020

Field-based method for assessing duration of infectivity for influenza A viruses in the environment

Understanding influenza A virus (IAV) persistence in wetlands is limited by a paucity of field studies relating to the maintenance of infectivity over time. The duration of IAV infectivity in water has been assessed under variable laboratory conditions, but results are difficult to translate to more complex field conditions. We tested a field-based method to assess the viability of IAVs in an Alaska wetland during fall and winter which incorporated physical and chemical properties of the waterbody in which samples were held. Filtered pond water was inoculated with avian fecal samples collected from the environment, aliquoted into a series of duplicate sealed vials and submerged back in the wetland for up to 132 days (October 2018–March 2019). Sample aliquots were sequentially recovered and tested for IAVs by rRT-PCR and virus isolation. One sample remained rRT-PCR positive for the duration of the study and virus isolation positive for 118 days. The surrounding water temperature was 1°–6 °C with near neutral pH (6.6–7.3) for the duration of the study. This proof of concept study demonstrates a protocol for testing the persistence of infectious IAV naturally shed from waterfowl under ambient environmental conditions.

Alaska↗

USGS2014

A comparison of high-resolution specific conductance-based end-member mixing analysis and a graphical method for baseflow separation of four streams in hydrologically challenging agricultural watersheds

Quantifying the relative contributions of different sources of water to a stream hydrograph is important for understanding the hydrology and water quality dynamics of a given watershed. To compare the performance of two methods of hydrograph separation, a graphical program [baseflow index (BFI)] and an end-member mixing analysis that used high-resolution specific conductance measurements (SC-EMMA) were used to estimate daily and average long-term slowflow additions of water to four small, primarily agricultural streams with different dominant sources of water (natural groundwater, overland flow, subsurface drain outflow, and groundwater from irrigation). Because the result of hydrograph separation by SC-EMMA is strongly related to the choice of slowflow and fastflow end-member values, a sensitivity analysis was conducted based on the various approaches reported in the literature to inform the selection of end-members. There were substantial discrepancies among the BFI and SC-EMMA, and neither method produced reasonable results for all four streams. Streams that had a small difference in the SC of slowflow compared with fastflow or did not have a monotonic relationship between streamflow and stream SC posed a challenge to the SC-EMMA method. The utility of the graphical BFI program was limited in the stream that had only gradual changes in streamflow. The results of this comparison suggest that the two methods may be quantifying different sources of water. Even though both methods are easy to apply, they should be applied with consideration of the streamflow and/or SC characteristics of a stream, especially where anthropogenic water sources (irrigation and subsurface drainage) are present.

Hydrological Processes↗

USGS2019

Evaluation of artificial cover units as a sampling technique and habitat enhancement for madtoms in rivers

Instream habitat degradation and loss are major threats to freshwater fishes and critical conservation issues among nongame species, due to a lack of research and knowledge concerning their habitat requirements. Instream physical cover is an important component of fish habitat, especially for benthic species that require cover for reproduction and shelter from predators. One such species is the Carolina Madtom Noturus furiosus, a small, imperiled, nongame catfish endemic to the Neuse and Tar river basins of North Carolina. To enhance understanding of instream cover dynamics, we constructed artificial cover units from terra cotta materials and deployed them in rivers to (1) evaluate if they could be an effective passive sampling technique to estimate detection and occupancy of the Carolina Madtom, and (2) determine their potential to enhance habitat in systems where instream cover has been lost. Artificial cover units were deployed at 8 sites in the Neuse and Tar river basins, and collected 30 Carolina Madtoms at 2 sites in the Tar River basin. Occupancy modeling estimated Carolina Madtom detection probability using artificial cover units at 0.92. Compared to other standardized sampling methods, artificial cover units were an efficient, passive sampling technique for detecting Carolina Madtoms. Observations also revealed that artificial cover units were occupied by Carolina Madtoms for reproduction. These findings provide natural resource managers an additional means to assess the status of this imperiled species using an inexpensive, passive sampling device that can provide spawning habitat, protection from predators, and help mitigate effects of instream habitat degradation.

North Carolina↗

USGS2018

Long-term effects of fire and harvest on carbon stocks of boreal forests in northeastern China

Context Boreal forests represent about one third of forest area and one third of forest carbon stocks on the Earth. Carbon stocks of boreal forests are sensitive to climate change, natural disturbances, and human activities. Aims The objectives of this study were to evaluate the effects of fire, harvest, and their spatial interactions on boreal forest carbon stocks of northeastern China. Methods We used a coupled forest landscape model (LANDIS PRO) and a forest ecosystem model (LINKAGES) framework to simulate the landscape-level effects of fire, harvest, and their spatial interactions over 150 years. Results Our simulation suggested that aboveground carbon and soil organic carbon are significantly reduced by fire and harvest over the whole simulation period. The long-term effects of fire and harvest on carbon stocks were greater than the short-term effects. The combined effects of fire and harvest on carbon stocks are less than the sum of the separate effects of fire and harvest. The response of carbon stocks was impacted by the spatial variability of fire and harvest regimes. Conclusion These results emphasize that the spatial interactions of fire and harvest play an important role in regulating boreal forest carbon stocks.

Annals of Forest Science↗

USGS2021

Synthesizing and analyzing long-term monitoring data: A greater sage-grouse case study

Long-term monitoring of natural resources is imperative for increasing the understanding of ecosystem processes, services, and how to manage those ecosystems to maintain or improve function. Challenges with using these data may occur because methods of monitoring changed over time, multiple organizations collect and manage data differently, and monetary resources fluctuate, affecting many aspects of data. Because many species respond to changes in habitat conditions and predator-prey relationships across different spatial scales that span management boundaries, greater efforts for collaborating are essential. We demonstrate the challenges and methods for standardizing greater sage-grouse ( Centrocercus urophasianus ) long-term monitoring data across the species range in the western United States to inform population modeling needs identified by the Western Association of Fish and Wildlife Agencies. We used automated and repeatable methods of standardizing data via custom open-source software ( grsg_lekdb ) to improve the scientific integrity of future sage-grouse population assessments within and among states. Data standardization included reconciling uses of different terminology and expunging unusable data, resulting in the removal of 26% of data records due to database insertion errors and modifications to >1 million values to correct formatting and typing errors. Our approaches maximized the inclusion of usable data and identified data that could inform detection probabilities, population trends, and monitoring guidelines. Using sage-grouse databases as an example, we identified the importance of data management and how quality assurance and quality control measures can improve the usefulness of these data for future research needs. Our methods of using informatics and concluding recommendations can support similar endeavors of flora and fauna monitoring programs, whether those efforts are to use existing data or support new monitoring programs.

Ecological Informatics↗

USGS2011

An analytical framework to assist decision makers in the use of forest ecosystem model predictions

The predictions from most forest ecosystem models originate from deterministic simulations. However, few evaluation exercises for model outputs are performed by either model developers or users. This issue has important consequences for decision makers using these models to develop natural resource management policies, as they cannot evaluate the extent to which predictions stemming from the simulation of alternative management scenarios may result in significant environmental or economic differences. Various numerical methods, such as sensitivity/uncertainty analyses, or bootstrap methods, may be used to evaluate models and the errors associated with their outputs. However, the application of each of these methods carries unique challenges which decision makers do not necessarily understand; guidance is required when interpreting the output generated from each model. This paper proposes a decision flow chart in the form of an analytical framework to help decision makers apply, in an orderly fashion, different steps involved in examining the model outputs. The analytical framework is discussed with regard to the definition of problems and objectives and includes the following topics: model selection, identification of alternatives, modelling tasks and selecting alternatives for developing policy or implementing management scenarios. Its application is illustrated using an on-going exercise in developing silvicultural guidelines for a forest management enterprise in Ontario, Canada.

Environmental Modelling and Software↗

USGS2010

Using generalized linear models to estimate selectivity from short-term recoveries of tagged red drum Sciaenops ocellatus: Effects of gear, fate, and regulation period

Estimating the selectivity patterns of various fishing gears is a critical component of fisheries stock assessment due to the difficulty in obtaining representative samples from most gears. We used short-term recoveries ( n = 3587) of tagged red drum Sciaenops ocellatus to directly estimate age- and length-based selectivity patterns using generalized linear models. The most parsimonious models were selected using AIC, and standard deviations were estimated using simulations. Selectivity of red drum was dependent upon the regulation period in which the fish was caught, the gear used to catch the fish (i.e., hook-and-line, gill nets, pound nets), and the fate of the fish upon recovery (i.e., harvested or released); models including all first-order interactions between main effects outperformed models without interactions. Selectivity of harvested fish was generally dome-shaped and shifted toward larger, older fish in response to regulation changes. Selectivity of caught-and-released red drum was highest on the youngest and smallest fish in the early and middle regulation periods, but increased on larger, legal-sized fish in the late regulation period. These results suggest that catch-and-release mortality has consistently been high for small, young red drum, but has recently become more common in larger, older fish. This method of estimating selectivity from short-term tag recoveries is valuable because it is simpler than full tag-return models, and may be more robust because yearly fishing and natural mortality rates do not need to be modeled and estimated.

North Carolina↗

USGS2021

Geochemistry and mineralogy of metallurgical slag

Slag is a waste product from the pyrometallurgical processing of natural ores or the recycling of man-made materials. This chapter provides an overview of the geochemical and mineralogical characteristics of different types of slag. A review of the analytical methods used to determine these characteristics is also provided. Ferrous slags include blast furnace, steelmaking, and ferroalloy slags; the compositions of these slags are generally dominated by Ca and Si, some with significant Al, Fe, and/or Mg. Whereas, the composition of non-ferrous slags, mostly from base-metal production, are generally dominated by Fe and Si with significant but lesser amounts of Al and Ca. As for primary mineralogical phases, olivine-group phases, spinels, and glass are common among all types of slag. Other silicates such as melilite, pyroxene, feldspars, and oxides also occur. Sulfides are more common in non-ferrous slags and metals and intermetallic compounds can be found in both base-metal and ferrous slags. Carbonates are generally exclusive of ferrous slags. The chemical composition of slag depends on the furnace feed, fluxes, fuel source, and furnace conditions and efficiency of metal extraction. The chemistry and texture of mineralogical phases found in slag reflect melt composition and cooling rates. Overall, the mineralogy and chemistry of slags will determine its fate as an environmental liability or a valuable resource.

Book chapter↗

USGS2013

Choosing and using climate change scenarios for ecological-impact assessments and conservation decisions

Increased concern over climate change is demonstrated by the many efforts to assess climate effects and develop adaptation strategies. Scientists, resource managers, and decision makers are increasingly expected to use climate information, but they struggle with its uncertainty. With the current proliferation of climate simulations and downscaling methods, scientifically credible strategies for selecting a subset for analysis and decision making are needed. Drawing on a rich literature in climate science and impact assessment and on experience working with natural resource scientists and decision makers, we devised guidelines for choosing climate-change scenarios for ecological impact assessment that recognize irreducible uncertainty in climate projections and address common misconceptions about this uncertainty. This approach involves identifying primary local climate drivers by climate sensitivity of the biological system of interest; determining appropriate sources of information for future changes in those drivers; considering how well processes controlling local climate are spatially resolved; and selecting scenarios based on considering observed emission trends, relative importance of natural climate variability, and risk tolerance and time horizon of the associated decision. The most appropriate scenarios for a particular analysis will not necessarily be the most appropriate for another due to differences in local climate drivers, biophysical linkages to climate, decision characteristics, and how well a model simulates the climate parameters and processes of interest. Given these complexities, we recommend interaction among climate scientists, natural and physical scientists, and decision makers throughout the process of choosing and using climate-change scenarios for ecological impact assessment.

Conservation Biology↗

USGS1981

Formalin preservation of avian blood for organochlorine analysis

Blood biopsy for chemical analysis is a valuable technique for evaluating chemical exposure of birds in the wild without harming the birds. Field conditions, however, often make sample storage difficult. Better methods than freezing are needed to improve the interpretive value of chemical analysis of the sample. The use of formalin was explored for this purpose. A pooled sample of blood containing naturally incorporated 1,1-bis-(p-chlorophenyl)-2,2,2-trichloroethane (DDT), 2,2-bis-(p-chlorophenyl)1,1 dichloroethylene (DDE), and dieldrin was subdivided into 30 samples, of which 10 were frozen, 10 more were kept at room temperature, and 10 were formalinized by adding I part of chemically pure formalin to 20 parts of blood. The formalinized samples yielded the highest and least variable concentrations of chemicals. The field procedures are outlined.

Book chapter↗

USGS2010

The green alga, Cladophora, promotes Escherichia coli growth and contamination of recreational waters in Lake Michigan

A linkage between Cladophora mats and exceedances of recreational water quality criteria has been suggested, but not directly studied. Th is study investigates the spatial and temporal association between Escherichia coli concentrations within and near Cladophora mats at two northwestern Lake Michigan beaches in Door County, Wisconsin. Escherichia coli concentrations in water underlying mats were significantly greater than surrounding water (p < 0.001). Below mat E. coli increased as the stranded mats persisted at the beach swash zone. Water adjacent to Cladophora mats had lower E. coli concentrations, but surpassed EPA swimming criteria the majority of sampling days. A signifi cant positive association was found between E. coli concentrations attached to Cladophora and in underlying water (p < 0.001). The attached E. coli likely acted as a reservoir for populating water underlying the mat. Fecal bacterial pathogens, however, could not be detected by microbiological culture methods either attached to mat biomass or in underlying water. Removal of Cladophora mats from beach areas may improve aesthetic and microbial water quality at affected beaches. These associations and potential natural growth of E. coli in bathing waters call into question the efficacy of using E. coli as a recreational water quality indicator of fecal contaminations. Copyright ?? 2010 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

Journal of Environmental Quality↗

USGS2013

Groundwater-quality data in the Cascade Range and Modoc Plateau study unit, 2010-Results from the California GAMA Program

Groundwater quality in the 39,000-square-kilometer Cascade Range and Modoc Plateau (CAMP) study unit was investigated by the U.S. Geological Survey (USGS) from July through October 2010, as part of the California State Water Resources Control Board (SWRCB) Groundwater Ambient Monitoring and Assessment (GAMA) Program’s Priority Basin Project (PBP). The GAMA PBP was developed in response to the California Groundwater Quality Monitoring Act of 2001 and is being conducted in collaboration with the SWRCB and Lawrence Livermore National Laboratory (LLNL). The CAMP study unit is the thirty-second study unit to be sampled as part of the GAMA PBP. The GAMA CAMP study was designed to provide a spatially unbiased assessment of untreated-groundwater quality in the primary aquifer system and to facilitate statistically consistent comparisons of untreated-groundwater quality throughout California. The primary aquifer system is defined as that part of the aquifer corresponding to the open or screened intervals of wells listed in the California Department of Public Health (CDPH) database for the CAMP study unit. The quality of groundwater in shallow or deep water-bearing zones may differ from the quality of groundwater in the primary aquifer system; shallow groundwater may be more vulnerable to surficial contamination. In the CAMP study unit, groundwater samples were collected from 90 wells and springs in 6 study areas (Sacramento Valley Eastside, Honey Lake Valley, Cascade Range and Modoc Plateau Low Use Basins, Shasta Valley and Mount Shasta Volcanic Area, Quaternary Volcanic Areas, and Tertiary Volcanic Areas) in Butte, Lassen, Modoc, Plumas, Shasta, Siskiyou, and Tehama Counties. Wells and springs were selected by using a spatially distributed, randomized grid-based method to provide statistical representation of the study unit (grid wells). Groundwater samples were analyzed for field water-quality indicators, organic constituents, perchlorate, inorganic constituents, radioactive constituents, and microbial indicators. Naturally occurring isotopes and dissolved noble gases also were measured to provide a dataset that will be used to help interpret the sources and ages of the sampled groundwater in subsequent reports. In total, 221 constituents were investigated for this study. Three types of quality-control samples (blanks, replicates, and matrix spikes) were collected at approximately 10 percent of the wells in the CAMP study unit, and the results for these samples were used to evaluate the quality of the data for the groundwater samples. Blanks rarely contained detectable concentrations of any constituent, suggesting that contamination from sample collection procedures was not a significant source of bias in the data for the groundwater samples. Replicate samples generally were within the limits of acceptable analytical reproducibility. Matrix-spike recoveries were within the acceptable range (70 to 130 percent) for approximately 90 percent of the compounds. This study did not attempt to evaluate the quality of water delivered to consumers; after withdrawal from the ground, untreated groundwater typically is treated, disinfected, and (or) blended with other waters to maintain water quality. Regulatory benchmarks apply to water that is served to the consumer, not to untreated groundwater. However, to provide some context for the results, concentrations of constituents measured in the untreated groundwater were compared with regulatory and non-regulatory health-based benchmarks established by the U.S. Environmental Protection Agency (USEPA) and CDPH, and to non-regulatory benchmarks established for aesthetic concerns by CDPH. Comparisons between data collected for this study and benchmarks for drinking water are for illustrative purposes only and are not indicative of compliance or non-compliance with those benchmarks. All organic constituents and most inorganic constituents that were detected in groundwater samples from the 90 grid wells in the CAMP study unit were detected at concentrations less than drinking-water benchmarks. Of the 148 organic constituents analyzed, 27 were detected in groundwater samples; concentrations of all detected constituents were less than regulatory and nonregulatory health-based benchmarks, and all were less than 1/10 of benchmark levels. One or more organic constituents were detected in 52 percent of the grid wells in the CAMP study unit: VOCs were detected in 30 percent, and pesticides and pesticide degradates were detected in 31 percent. Trace elements, major ions, nutrients, and radioactive constituents were sampled for at 90 grid wells in the CAMP study unit, and most detected concentrations were less than health-based benchmarks. Exceptions include three detections of arsenic greater than the USEPA maximum contaminant level (MCL-US) of 10 micrograms per liter (µg/L), two detections of boron greater than the CDPH notification level (NL-CA) of 1,000 µg/L, two detections of molybdenum greater than the USEPA lifetime health advisory level (HAL-US) of 40 µg/L, two detections of vanadium greater than the CDPH notification level (NL-CA) of 50 µg/L, one detection of nitrate, as nitrogen, greater than the MCL-US of 10 milligrams per liter (mg/L), two detections of uranium greater than the MCL-US of 30 µg/L and the MCL-CA of 20 picocuries per liter (pCi/L), one detection of radon-222 greater than the proposed MCL-US of 4,000 pCi/L, and two detections of gross alpha particle activity greater than the MCL-US of 15 pCi/L. Results for inorganic constituents with non-regulatory benchmarks set for aesthetic concerns showed that iron concentrations greater than the CDPH secondary maximum contaminant level (SMCL-CA) of 300 µg/L were detected in four grid wells. Manganese concentrations greater than the SMCL-CA of 50 µg/L were detected in nine grid wells. Chloride and TDS were detected at concentrations greater than the upper SMCL-CA benchmarks of 500 mg/L and 1,000 mg/L, respectively, in one grid well. Microbial indicators (total coliform and Escherichia coli [E. coli]) were detected in 11 percent of the 83 grid wells sampled for these analyses in the CAMP study unit. The presence of total coliform was detected in nine grid wells, and the presence of E. coli was detected in one of these same grid wells.

California↗

USGS1972

Water in St. John, U.S. Virgin Islands

Water for domestic and municipal supply on St. John, in the past, has been obtained from rain catchments, dug wells, and barge shipments from St. Thomas and Puerto Rico. As a result of this study, small ground-water supplies have been developed for the Virgin Islands National Park. Ground water occurs in significant but limited quantities in the fractured volcanic rock throughout most of the Island. Yield of wells in this aquifer ranges from less than 100 to about 2,000 gpd (gallons per day). The average long-term yield of the three drilled wells in use by the National Park Service in 1967 was about 1,000 gpd. Yield ofl,000 to 5,000 gpd may be expected in the Coral Bay and the Reef Bay areas. Estimated total recharge of the fractured volcanic rock on St. John, based on a recharge of 1 to 3 inches per year, is 1,000,000 to 3,000,000 gpd. Perhaps as much as a quarter to a third of this water could be developed practically, depending on the rainfall in a given year. The chemical quality of the ground water in the fractured-rock aquifer in areas uncontaminated by sea water ranges from 600 to 2,000 mg/l (milligrams per liter) or more dissolved solids. Water from-formations in the higher altitudes is of better quality than that in the lower formations. Small quantities of ground water are available from beach sand, alluvium, and fractured rock near the sea. However, these sources tend to be brackish and are subject to salt-water encroachment. There are no perennial streams on St. John. There are a few spring-fed pools in stream channels, however, that are sustained, except in severe drought. Storm runoff is estimated to average 1 inch over the island annually, and evaporation from open water surfaces is about 70 inches per year. Ponds can be developed, but because of the high .evaporation they may be unreliable during droughts. Rain water collected in cisterns from roofs and catchments yield about 50 gpd per 1,000 square feet of catch area during an average year of rainfall. This is the main method of Water supply for domestic use on the Island; it will probably be continued even if a public distribution system is made available, because of the limited quantity of other natural water.

Open-File Report↗

USGS2018

Groundwater discharge characteristics for selected streams within the Loup River Basin, Nebraska, 2014–16

Streams in the Loup River Basin are sensitive to groundwater withdrawals because of the close hydrologic connection between groundwater and surface water. Groundwater discharge is the primary component of streamflow in the Loup River Basin and constitutes more than 90 percent of streamflow in the central part of the Sand Hills. To improve the understanding of geologic controls and various climatic and land-use changes on groundwater discharge, the U.S. Geological Survey (USGS), in cooperation with the Upper Loup Natural Resources District (NRD), the Lower Loup NRD, and the Nebraska Environmental Trust, studied the spatial and temporal characteristics of groundwater discharge within the Loup River Basin. This report documents the methods of data collection and analysis, which include the collection of approximately 350 river miles of aerial thermal infrared imagery and continuous groundwater-level and temperature data from six streamflow-gaging stations within the Loup River Basin. The results from the stream reconnaissance and examination of aerial thermal infrared imagery demonstrated the influence of the surficial and subsurface geology on the spatial characteristics of groundwater discharge to streams in the Loup River Basin. At the headwaters of the South Loup River, streamflow is sustained and increased from focused groundwater discharge emanating from Quaternary deposits at many small (less than 0.1 cubic foot per second) focused points. The volume of water produced from this dense network of focused groundwater discharge points along the North Fork South Loup River is sufficient to provide approximately 40 percent of the flow measured at the South Loup River at Arnold, Nebraska streamflow-gaging station (USGS station 06781600) during the irrigation season. Approximately 5 miles downstream from the South Loup River at Arnold, Nebr., streamflow-gaging station, the river incises into Pliocene-age sand and gravel deposits, which provide additional groundwater discharge to the stream. The streamflow of the South Loup River increases by a factor of 5 across a 62-mile reach of the middle South Loup River. Increases in streamflow along the upper Dismal River result from a dense network of focused groundwater discharge points within semiconsolidated Pliocene-age deposits. Below the Dismal River near Thedford, Nebr., streamflow-gaging station (USGS station 06775900), the Dismal River incises into the Ogallala Formation over a short reach before flowing over coarser, more permeable Quaternary-age alluvial deposits. Diffuse groundwater discharge sustains and increases the streamflow of the lower Dismal River in this reach. Groundwater sapping was evident on some stream reaches and has increased the size and flow of focused groundwater discharge points. Previous researchers have documented streambed incision and groundwater sapping on the upper Dismal River that have created and enlarged focused groundwater discharge points capturing additional groundwater. Similar processes appear to have played a role in the formation of larger focused groundwater discharge points, which sustain the flow of the middle South Loup River. The constant flow of groundwater into the South Loup River has removed finer-grained Quaternary sediments and further exposed Pliocene-age gravel deposits. Headward erosion is evident where some of the large focused groundwater discharge points have incised their own draws and terminate in bowl-like depressions away from the stream. Within the Loup River NRDs, the percentage of groundwater-irrigated land in a stream basin is one factor that affects groundwater discharge to streams. A striking example was at the South Loup River at Saint Michael, Nebr., groundwater and streamflow-gaging station (USGS station 06784000) where the shallow groundwater levels declined below the level of the stream during the middle to late part of the growing season (July to September) when consumptive groundwater use was at its peak. The South Loup River Basin above the South Loup River at Saint Michael, Nebr., streamflow-gaging station has the highest percentage of groundwater-irrigated row crops of all the basins examined in this study. Continuous groundwater and surface-water levels measured at the North Loup River at the Taylor, Nebr., streamflow-gaging station (USGS station 06786000) indicate that the stream is receiving groundwater throughout the year; however, when consumptive groundwater use peaks during the middle to late part of the growing season (July to September), the difference in elevation between the groundwater level and the stream elevation decreases, which indicates a reduction in the amount of groundwater discharge received.

Nebraska↗

USGS1988

Distribution of gases in the unsaturated zone at a low-level radioactive-waste disposal site near Sheffield, Illinois

The unsaturated zone is a medium that provides pneumatic communication for the movement of gases from wastes buried in landfills to the atmosphere, biota, and groundwater. Gases in unsaturated glacial and eolian deposits near a waste-disposal trench at the low-level radioactive-waste disposal site near Sheffield, Bureau County, Illinois, were identified, and the spatial and temporal distributions of the partial pressures of those gases were determined for the period January 1984 through January 1986. Methods for the collection and analyses of the gases are described, as are geologic and hydrologic characteristics of the unsaturated zone that affect gas transport. The identified gases, which are of natural and of waste origin, include nitrogen, oxygen, and argon, carbon dioxide, methane, propane, butane, tritiated water vapor, 14carbon dioxide, and 222 radon. Concentrations of methane and 14carbon dioxide originated at the waste, as shown by partial-pressure gradients of the gases; 14carbon dioxide partial pressures exceeded natural background partial pressures by factors greater than 1 million at some locations. Variations in partial pressures of oxygen and carbon dioxide were seasonal among piezometers because of increased root and soil-microbe respiration during summer. Variations in methane and 14carbon dioxide partial pressures were apparently related to discrete releases from waste sources at unpredictable intervals of time. No greater than background partial pressures for tritiated water vapor or 222 radon were measured. (USGS)

Water-Resources Investigations Report↗

USGS2005

Methods for synthesis of some jarosites

Experimental procedures in this report summarize attempts to synthesize potassium-, hydronium-, sodium-, and mixed-composition (hydronium-bearing) jarosites. After experimentation, some acceptable combinations of chemical and physical factors were found to routinely synthesize chemically different jarosites, which were used as part of a characterization study of some natural and synthetic jarosites. Jarosite is a sulfate mineral that is common in geologic settings where iron sulfide minerals such as pyrite or marcasite are subject to oxidative weathering. The presence of jarosite is a hallmark of acidic conditions. Jarosite forms as a secondary mineral in weathered sulfidic ores, coal mine wastes, on oxidizing mine wastes, and in streams affected by acid mine drainage. Jarosite also forms in acid-sulfate soils, as an alteration product of sulfidic shales, and in hydrothermal environments. Because of its important role in earth surface processes, the USGS is conducting mineralogical, geochemical, and remote sensing studies to characterize natural jarosites and to elucidate its stability range and conditions of formation. The presence of jarosite is not limited to the Earth. The recent identification of jarosite in the rocks at the Meridiani Planum on Mars has given planetary geologists reason to think that jarosite may be evidence of relict lacustrine (lake systems) or hydrothermal (water enriched magma emanations) systems on the Martian surface. USGS scientists are currently developing jarosite detection systems that can be placed on orbiting spectrometers. One day these systems may guide Mars landers to sites abundant in jarosite, sites most likely to have sheltered ancient Martian life.

Techniques and Methods↗

USGS2005

Comparative soil CO2 flux measurements and geostatistical estimation methods on Masaya volcano, Nicaragua

We present a comparative study of soil CO 2 flux ( F C O 2 "> F C O 2 ) measured by five groups (Groups 1–5) at the IAVCEI-CCVG Eighth Workshop on Volcanic Gases on Masaya volcano, Nicaragua. Groups 1–5 measured F C O 2 using the accumulation chamber method at 5-m spacing within a 900 m 2 grid during a morning (AM) period. These measurements were repeated by Groups 1–3 during an afternoon (PM) period. Measured F C O 2 ranged from 218 to 14,719 g m −2 day −1 . The variability of the five measurements made at each grid point ranged from ±5 to 167%. However, the arithmetic means of fluxes measured over the entire grid and associated total CO 2 emission rate estimates varied between groups by only ±22%. All three groups that made PM measurements reported an 8–19% increase in total emissions over the AM results. Based on a comparison of measurements made during AM and PM times, we argue that this change is due in large part to natural temporal variability of gas flow, rather than to measurement error. In order to estimate the mean and associated CO 2 emission rate of one data set and to map the spatial F C O 2 distribution, we compared six geostatistical methods: arithmetic and minimum variance unbiased estimator means of uninterpolated data, and arithmetic means of data interpolated by the multiquadric radial basis function, ordinary kriging, multi-Gaussian kriging, and sequential Gaussian simulation methods. While the total CO 2 emission rates estimated using the different techniques only varied by ±4.4%, the F C O 2 maps showed important differences. We suggest that the sequential Gaussian simulation method yields the most realistic representation of the spatial distribution of F C O 2 , but a variety of geostatistical methods are appropriate to estimate the total CO 2 emission rate from a study area, which is a primary goal in volcano monitoring research.

Masaya↗

USGS2023

Exposure to risk factors experienced during migration is not associated with recent Vermivora warbler population trends

Context Understanding the factors limiting populations of animals is critical for effective conservation. Determining which factors limit populations of migratory species can be especially challenging because of their reliance on multiple, often geographically distant regions during their annual cycles. Objectives We investigated whether distribution-wide variation in recent breeding population trends was more strongly associated with exposure to risk factors experienced during migration (i.e., natural and anthropogenic threats often associated with increased mortality or carry-over effects) or factors associated with breeding and nonbreeding areas in golden-winged warblers ( Vermivora chrysoptera ) and blue-winged warblers ( V. cyanoptera ), two Nearctic-Neotropical migrants experiencing regionally variable population trends. Methods We used geolocator data from 85 Vermivora warblers ( n = 90 geolocator tracks) tracked from North American breeding locations and Central American nonbreeding locations from 2013 to 2017 to determine variation in space use among populations. We assessed whether differences in space use among populations of Vermivora warblers during migration were associated with exposure to migration risk-factors and whether increased relative exposure to migration risk factors was associated with population declines at regional and subregional scales. Results Regional and subregional populations of Vermivora warblers exhibited variation in space use and exposure to anthropogenic and natural risk-factors. However, we found no evidence that recent variation in population trends of Vermivora warblers was associated with risk-factors experienced by different populations during migration. Instead, factors associated with land cover-types in breeding and nonbreeding areas were more strongly associated with recent population trends. Conclusions Understanding how populations of migratory birds are affected by factors experienced during migration is critical for their conservation. We did not find evidence that variation in exposure to migration risk-factors is associated with recent regional or subregional variation in Vermivora warbler population trends. Consequently, our results suggest that efforts to reverse ongoing population declines of Vermivora warblers may be more effective if directed toward conservation actions targeting limiting factors within the breeding and nonbreeding periods versus those directed at conditions encountered during migration. We caution that geographic variation in projected land-use change may differentially affect areas used by different populations of Vermivora warblers during migration, posing a potential threat to these species in the future.

Landscape Ecology↗