Variable-density groundwater flow and contaminant transport, Operable Unit 1, Naval Base Kitsap, Keyport, Washington
Released October 21, 2020 15:42 EST
2020, Scientific Investigations Report 2020-5066
Richard M. Yager, Wendy B. Welch, Alexander Headman, Richard S. Dinicola
Chlorinated volatile organic compounds (CVOCs) have migrated to groundwater beneath a former 9-acre landfill at Operable Unit 1 (OU-1) on Naval Base Kitsap, which was active from the 1930s through 1973 on the Keyport Peninsula, in Kitsap County, Washington. Biodegradation of CVOCs at OU-1 limits the mass of dissolved-phase CVOCs in groundwater that discharges to surface water, but contaminant concentrations up to 630 milligrams per liter persist in localized areas, likely from the dissolution of residual, non-aqueous phase liquids. Variable-density groundwater-flow and contaminant-transport models were developed using the SEAWAT-Version 4 computer program to simulate the direction and rate of groundwater flow in a 5.9 square-mile (mi2) - area surrounding the Keyport Peninsula, to estimate the CVOC mass in groundwater and the rate of mass loading, and to assess possible remedial activities at OU-1.
The study area is underlain by Quaternary deposits consisting of alternating glacial and interglacial sediments ranging from 500 to 1,500 feet (ft) thick. A hydrogeologic model delineated a sequence of 10 units including a relatively thin package (less than 100 ft) of recent sediments (Vashon Stade and younger) beneath the Keyport Peninsula that are underlain by the much thicker (more than 300 ft) Clover Park Aquitard, which overlies a confined, sea-level aquifer.
Simulated effects of pumping in the Death Valley Regional Groundwater Flow System, Nevada and California—Selected management scenarios projected to 2120
Released October 21, 2020 13:34 EST
2020, Scientific Investigations Report 2020-5103
Nora C. Nelson, Tracie R. Jackson
Declining water levels and reduced natural discharge at springs, seeps, and phreatophyte areas primarily are the result of decades of groundwater development in the Death Valley regional flow system, in Nevada and California. A calibrated groundwater-flow model was used to simulate potential future effects of groundwater pumping on water levels and natural groundwater discharge in the study area. Effects of climate change on future groundwater pumping were not considered and were beyond the scope of the study. Four groundwater-pumping scenarios were developed by stakeholders to predict and compare (1) the extent of regional water-level declines; (2) drawdown at Devils Hole; and (3) reductions in natural discharge at select discharge areas, including the Amargosa Wild and Scenic River, the Ash Meadows discharge area, the Furnace Creek area, and Stump Spring. Scenarios were simulated from 1913 to 2120, with historical pumping occurring from 1913 to 2010, historical 2010 pumping rates projected from 2010 to 2020, and scenario pumping beginning in 2020. Pumping scenarios included a base case and scenarios A, B, and C. The base case projected 2010 pumping rates from 2010 to 2120, and scenarios A, B, and C projected base case pumping plus additional pumping at various locations from 2020 to 2120. By 2020, historical (1913–2020) pumping resulted in the propagation of simulated drawdown of 1 foot (ft) or more westward from Pahrump Valley to areas north of Shoshone in the Pahrump to Death Valley South (PDVS) groundwater basin and the merging of simulated 1-ft drawdown contours between the Alkali Flat–Furnace Creek Ranch (AFFCR) and Ash Meadows groundwater basins. In the base case scenario, extent and magnitude of simulated drawdown continued to increase in the Ash Meadows and AFFCR groundwater basins from 2020 to 2120. In the base case, the magnitude of simulated drawdown continued to increase in western Pahrump Valley from 2020 to 2120, whereas simulated water levels rose in eastern Pahrump Valley from 2020 to 2070 and then stabilized from 2070 to 2120. Scenarios A and B primarily affected the PDVS and AFFCR groundwater basins by increasing the magnitude of drawdown in 2120, compared to the base case. In scenario C, drawdown propagated throughout a high-transmissivity part of the carbonate aquifer known as the megachannel, greatly affecting water levels in the Ash Meadows discharge area. Scenario C resulted in an additional 10–100 ft of drawdown (compared to the base case) throughout the southeastern part of the Ash Meadows groundwater basin by 2120. Simulated drawdowns in Devils Hole in 2120 were 3.2, 3.4, 3.8, and 25.4 ft for the base case and scenarios A, B, and C, respectively. The federally mandated minimum water level for Devils Hole is 2.7 ft below a reference point. In 2020, the simulated water level in Devils Hole was above the minimum water level, at 1.7 ft below the reference. Simulated water levels in Devils Hole fell below the federally mandated water level by 2078, 2073, 2058, and 2025 for the base case and scenarios A, B, and C, respectively, assuming a hypothetical recharge scenario of constant natural recharge. Simulated reductions in predevelopment (natural) discharge at select discharge areas ranged from 3 to 38 percent by 2120 for all scenarios. Amargosa Wild and Scenic River was the least affected discharge area with simulated capture rates ranging from 3 to 4 percent of predevelopment discharge by 2120. Ash Meadows discharge area was greatly affected by groundwater pumping in scenario C with a simulated capture rate of 38 percent, compared to simulated capture rates of 8, 8, and 9 percent for the base case, scenario A, and scenario B, respectively, in 2120. Simulated capture rates in the Furnace Creek area ranged from 10 to 11 percent for all scenarios in 2120. Simulated capture rates at Stump Spring ranged from 32 to 36 percent for all scenarios in 2120.
Arsenic and uranium occurrence in private wells in Connecticut, 2013–18—A spatially weighted and bedrock geology assessment
Released October 19, 2020 14:00 EST
2020, Open-File Report 2020-1111
Eliza L. Gross, Craig J. Brown
The U.S. Geological Survey, in cooperation with the Connecticut Department of Public Health, conducted a study to determine the presence of arsenic and uranium in private drinking water wells in Connecticut. Samples were collected during 2013–18 from wells completed in 115 geologic units, with 2,433 samples analyzed for arsenic and 2,191 samples analyzed for uranium. The study concluded four major findings.
Estimated groundwater withdrawals from principal aquifers in the United States, 2015
- In a spatially weighted analysis of groundwater samples collected from more than 2,000 private wells in bedrock aquifers in Connecticut, 3.9 percent of collected samples contained arsenic concentrations greater than the U.S. Environmental Protection Agency’s (EPA) maximum contaminant level (MCL) of 10 micrograms per liter (µg/L), and 4.7 percent of collected samples contained uranium concentrations greater than the EPA MCL of 30 µg/L.
- Of the 2,433 water samples collected and analyzed from bedrock aquifers in Connecticut, 4.2 percent (102) contained arsenic concentrations at greater than 10 µg/L, and of the 2,191 water samples collected and analyzed from bedrock aquifers in Connecticut, 5.4 percent (118) contained uranium concentrations greater than 30 µg/L.
- Uranium concentrations greater than or equal to 1 µg/L are relatively ubiquitous across the State of Connecticut, with these concentrations present in 44.9 percent of the State, according to spatially weighted statewide-scale proportion analysis.
- Of the 115 geologic units studied, 44 had at least one sample with arsenic or uranium concentrations that exceeded the respective constituent’s EPA MCL.
Released October 16, 2020 15:20 EST
2020, Circular 1464
John K. Lovelace, Martha G. Nielsen, Amy L. Read, Chid J. Murphy, Molly A. Maupin
In 2015, about 84,600 million gallons per day (Mgal/d) of groundwater were withdrawn in the United States for various uses including public supply, self-supplied domestic, industrial, mining, thermoelectric power, aquaculture, livestock, and irrigation. Of this total, about 94 percent (79,200 Mgal/d) was withdrawn from principal aquifers, which are defined as regionally extensive aquifers or aquifer systems that have the potential to be used as sources of water of suitable quality and quantity to meet various needs. The remaining 6 percent (5,400 Mgal/d) was withdrawn from other, nonprincipal aquifers in the United States.
Sixty-six principal aquifers belonging to 5 major lithologic groups have been identified and delineated in the United States, including Puerto Rico and the U.S. Virgin Islands. Of the water withdrawn from principal aquifers in 2015, 81 percent (63,900 Mgal/d) was from the unconsolidated and semiconsolidated sand and gravel lithologic group, 7.1 percent (5,630 Mgal/d) was from the igneous and metamorphic-rock lithologic group, 6.8 percent (5,360 Mgal/d) was from the carbonate-rock lithologic group, 3.4 percent (2,680 Mgal/d) was from the sandstone lithologic group, and 2.2 percent (1,710 Mgal/d) was from the sandstone and carbonate-rock lithologic group.
The most heavily pumped of the 24 principal aquifers and aquifer systems within the unconsolidated and semiconsolidated sand and gravel lithologic group were the High Plains aquifer (12,300 Mgal/d), Mississippi River Valley alluvial aquifer (12,100 Mgal/d), Central Valley aquifer system (11,100 Mgal/d), and Basin and Range basin-fill aquifers (7,390 Mgal/d). Withdrawals for irrigation were 48,100 Mgal/d and accounted for 75 percent of the total withdrawals from this lithologic group. Although unconsolidated sand and gravel aquifers are widely distributed and were used as sources of water in all States except Hawaii and the U.S. Virgin Islands, 56 percent of the total withdrawn from unconsolidated and semiconsolidated sand and gravel aquifers was in just four States: California (15,600 Mgal/d), Arkansas (9,560 Mgal/d), Nebraska (5,570 Mgal/d), and Texas (4,830 Mgal/d).
The most heavily pumped of the seven principal aquifers within the igneous and metamorphic-rock lithologic group were the Snake River Plain (2,930 Mgal/d) and Columbia Plateau basaltic-rock aquifers (1,080 Mgal/d), which are located in the northwestern United States and together accounted for 71 percent of the water withdrawn from this lithologic group. Withdrawals for irrigation were 4,190 Mgal/d and accounted for more than 74 percent of the total withdrawals from this lithologic group. Seventy-eight percent of the withdrawals from igneous and metamorphic-rock aquifers were in three States: Idaho (3,230 Mgal/d), Washington (614 Mgal/d), and Oregon (528 Mgal/d).
The most heavily pumped of the 15 principal aquifers and aquifer systems within the carbonate-rock lithologic group were the Floridan aquifer system (3,180 Mgal/d) and the Biscayne aquifer (679 Mgal/d), which are in the southeastern United States and together accounted for almost 72 percent of the withdrawals from this lithologic group. Withdrawals for public supply (2,440 Mgal/d) and irrigation (1,610 Mgal/d) together accounted for almost 76 percent of the total withdrawals from this lithologic group. Although water was withdrawn from carbonate-rock aquifers in 35 States, 71 percent of the total withdrawn was in Florida (3,020 Mgal/d) and Georgia (785 Mgal/d).
The most heavily pumped of the 15 principal aquifers within the sandstone lithologic group was the Cambrian-Ordovician aquifer system (921 Mgal/d), which is in the north-central United States and accounted for 34 percent of the water withdrawn from this lithologic group. Withdrawals for public supply were 1,030 Mgal/d and accounted for 38 percent of the total withdrawals from this lithologic group. Although sandstone aquifers were used as sources of water in 32 States, 45 percent of the total withdrawn from sandstone aquifers was in five States: Minnesota (321 Mgal/d), Wisconsin (319 Mgal/d), Kansas (193 Mgal/d), Illinois (187 Mgal/d), and Pennsylvania (179 Mgal/d).
The most heavily pumped of the five principal aquifers and aquifer systems within the sandstone and carbonate-rock lithologic group were the Edwards-Trinity aquifer system (661 Mgal/d) in the south-central United States and the Valley and Ridge aquifers (551 Mgal/d) of the eastern United States, which together accounted for 71 percent of total withdrawals from this lithologic group. Withdrawals from sandstone and carbonate-rock aquifers for public-supply (713 Mgal/d), irrigation (469 Mgal/d), and self-supplied domestic (253 Mgal/d) uses accounted for about 84 percent of the total withdrawals from this lithologic group. Although water was withdrawn from sandstone and carbonate-rock aquifers in 25 States, 65 percent of the total withdrawn was in Texas (651 Mgal/d), Pennsylvania (238 Mgal/d), and Florida (223 Mgal/d).
Delineation of flood-inundation areas in Grapevine Canyon near Scotty’s Castle, Death Valley National Park, California
Released October 16, 2020 10:48 EST
2020, Scientific Investigations Report 2020-5082
Christopher M. Morris, Toby L. Welborn, J. Toby Minear
On October 18, 2015, a large flood caused considerable damage in Grapevine Canyon near Death Valley Scotty Historic District, in Death Valley National Park, California. Significant channel changes had limited the applicability of previously created flood-inundation maps to current conditions. Predicted flood-inundation maps for Scotty’s Castle were updated using one-dimensional hydraulic models. A digital terrain model was created for the study area using a terrestrial laser scanner for use in the hydraulic models. Estimations of the 4, 2, 1, 0.5, and 0.2-percent annual exceedance probability flood streamflows (previously known as the 25, 50, 100, 250, and 500-year floods) were computed from regional flood regression equations. The estimated flood streamflows were used with the hydraulic models to compute water surface elevations that were mapped on the digital terrain model. The results indicate inundation of the visitor center and park offices occurs by the 4-percent annual exceedance probability flood. Bridge and embankment overtopping occurs by the 2-percent annual exceedance probability flood. Sections of Grapevine Canyon Road and the parking lot are inundated by the 4-percent annual exceedance probability flood and above streamflows. None of the computed streamflows reach Scotty’s Castle main building.
Aquifer transmissivity in Nassau, Queens, and Kings Counties, New York, estimated from specific-capacity tests at production wells
Released October 15, 2020 15:50 EST
2020, Open-File Report 2020-1108
John H. Williams, Madison Woodley, Jason S. Finkelstein
As part of a cooperative effort between the U.S. Geological Survey and the New York State Department of Environmental Conservation to evaluate the sustainability of Long Island’s sole-source aquifer system, the transmissivities of four aquifers were estimated from specific-capacity tests at 447 production wells in Nassau, Queens, and Kings Counties on Long Island, New York. The specific-capacity test data, which included pumping rate, pumping duration, and drawdown, were obtained from published and unpublished records of driller-reported acceptance tests collected at production wells screened in the upper glacial, Jameco, Magothy, or Lloyd aquifers. Pumping rates from the production wells during the tests generally were greater than 400 gallons per minute and ranged up to 1,800 gallons per minute. Pumping duration generally was 8 hours or more. Transmissivities were estimated from the specific-capacity data by the Cooper-Jacob approximation of the Theis equation. The transmissivity estimates are considered rough approximations because the aquifers do not meet the ideal assumptions of the method, well losses and partial penetration were not accounted for, and aquifer storage coefficients were not known but were only estimated from available data.
The transmissivities estimated from production wells screened in the upper glacial aquifer in the outwash plain south of the moraine generally were greater than those of the aquifer north of the moraine. The transmissivities estimated from the wells screened in the upper glacial aquifer south of the moraine typically ranged (as defined by the 10th and 90th percentiles) from 3,800 to 15,000 feet squared per day (ft2/d), with a median value of 7,300 ft2/d. The transmissivities estimated from the wells screened in the upper glacial aquifer north of the moraine typically ranged from 2,100 to 7,400 ft2/d, with a median value of 4,400 ft2/d. The Jameco aquifer generally had the highest estimated transmissivities of all the aquifers analyzed. The estimated transmissivities for the Jameco aquifer typically ranged from 5,500 to 43,000 ft2/d, with a median value of 16,000 ft2/d. The Magothy and Lloyd aquifers had similar estimated transmissivities. The transmissivities estimated for the Magothy aquifer typically ranged from 2,700 to 13,000 ft2/d, with a median of 7,100 ft2/d. The estimated transmissivities of the Lloyd typically ranged from 3,000 to 14,000 ft2/d, with a median of 7,200 ft2/d.
Principles and mechanisms of wildlife population persistence in the face of disease
Released October 15, 2020 09:53 EST
2020, Frontiers in Ecology and Environment (8)
Robin E. Russell, Graziella Vittoria Direnzo, J. Szymanski, Katrina Elizabeth Alger, Evan H. Campbell Grant
Emerging infectious diseases can result in species declines and hamper recovery efforts for at-risk populations. Generalizing considerations for reducing the risk of pathogen introduction and mitigating the effects of disease remains challenging and inhibits our ability to provide guidance for species recovery planning. Given the growing rates of emerging pathogens globally, we identify key principles and mechanisms for maintaining sustainable populations in the face of emerging diseases (including minimizing the risk of pathogen introductions and their future effects on hosts). Our synthesis serves as a reference for minimizing the risk of future disease outbreaks, mitigating the deleterious effects of future disease outbreaks on species extinction risk, and a review of the theoretical and/or empirical examples supporting these considerations.
Visually communicating future climate in a web environment
Released October 15, 2020 06:44 EST
2020, Weather, Climate, and Society (12) 877-896
Corey Davis, Heather D Aldridge, Ryan Boyles, Karen McNeal, Lindsay C. Mauldin, Rachel M. Atkins
While there is growing demand for use of climate model projections to understand the potential impacts of future climate on resources, there is a lack of effective visuals that convey the range of possible climates across spatial scales and with uncertainties that potential users need to inform their impact assessments and studies. We use usability testing including eye tracking to explore how a group of resource professionals (foresters) interpret and understand a series of graphical representations of future climate change, housed within a web-based decision support system (DSS), that address limitations identified in other tools. We find that a three-map layout effectively communicates the spread of future climate projections spatially, that location-specific information is effectively communicated if depicted both spatially on a map and temporally on a time series plot, and that model error metrics may be useful for communicating uncertainty and in demonstrating the utility of these future climate datasets.
Utica shale play oil and gas brines: Geochemistry and factors influencing wastewater management
Released October 14, 2020 10:27 EST
2020, Environmental Science & Technology
Madalyn S. Blondes, Jenna L. Shelton, Mark A Engle, Jason Trembly, Colin A. Doolan, Aaron M. Jubb, Jessica Chenault, Elisabeth L. Rowan, Ralph J. Haefner, Brian E. Mailot
Accounting for land in the United States: Integrating physical land cover, land use, and monetary valuation
The Utica and Marcellus Shale Plays in the Appalachian Basin are the fourth and first largest natural gas producing plays in the United States, respectively. Hydrocarbon production generates large volumes of brine (“produced water”) that must be disposed of, treated, or reused. Though Marcellus brines have been studied extensively, there are few studies from the Utica Shale Play. This study presents new brine chemical analyses from 16 Utica Shale Play wells in Ohio and Pennsylvania. Results from Na–Cl–Br systematics and stable and radiogenic isotopes suggest that the Utica Shale Play brines are likely residual pore water concentrated beyond halite saturation during the formation of the Ordovician Beekmantown evaporative sequence. The narrow range of chemistry for the Utica Shale Play produced waters (e.g., total dissolved solids = 214–283 g/L) over both time and space implies a consistent composition for disposal and reuse planning. The amount of salt produced annually from the Utica Shale Play is equivalent to 3.4% of the annual U.S. halite production. Utica Shale Play brines have radium activities 580 times the EPA maximum contaminant level and are supersaturated with respect to barite, indicating the potential for surface and aqueous radium hazards if not properly disposed of.
Released October 14, 2020 08:04 EST
2020, Ecosystem Services (46)
Scott A. Wentland, Zachary H. Ancona, Kenneth J. Bagstad, James W. Boyd, Julie L. Hass, Marina Gindelsky, Jeremy G. Moulton
Geologic and mineral map (modified from the 1975 original map compilation by A.S. Shadchinev and others) and hyperspectral surface materials maps of the Ghorband, Salang, and Panjsher River Basins; Kapisa, Panjsher, Parwan, and Baghlan Provinces, Afghanistan
Released October 13, 2020 12:15 EST
2020, Open-File Report 2020-1101
The geologic map and cross sections are a redrafted and modified version of the Geologic map and map of mineral resources of the basins of Ghorband, Salang, and Panjsher; located in the Kapisa, Panjsher, Parwan, and Baghlan Provinces, Afghanistan. The original map and cross sections are contained in an unpublished Soviet report no. 1162A (Shadchinev and others, 1975) prepared in cooperation with the Ministry of Mines and Industries of the Royal Government of Afghanistan, in Kabul during 1975, under contract no. 55–184/17500. This redrafted map consists of parts of quadrangle map sheets 503–F, 504–C, 504–D, 504–E, and 504–F shown on an index map that can be found on the original 1:100,000-scale map by Shadchinev and others (1975). The redrafted map and cross sections illustrate the mineral deposits and geologic structure of the Ghorband, Salang, and Panjsher River Basins. Because there were no location coordinates provided on the original Soviet map, the map was registered to drainage patterns identified by contours from the Global Digital Elevation Model (GDEM). The end result can only be considered a best fit for the map extend, and some features may not be positioned in their correct geographic location.
The redrafted geologic map and cross sections reproduce the topology of rock units, contacts, and faults of the original Soviet map and cross sections, and includes minor modifications based on our examination of the originals. Table 1, provided on both map sheets 1 and 2, shows mineral commodity locations also from the original Soviet map. However, because of the poor quality of the original map, some map features could not be identified and some may be misinterpreted. Further, we have attempted to translate the original Russian terminology and rock classifications into modern English geologic usage as literally as possible without changing any genetic or process-oriented implications in the original rock-unit descriptions. We also use the rock-unit age designations from the original maps, however, rock-unit colors and symbols differ from the colors and symbols shown on the original version. Unit colors were selected according to the color and pattern scheme of the Commission for the Geological Map of the World (http://www.ccgm.org). Unit symbols were assigned based on the geologic age and unit descriptions provided on the original Soviet map. Elevations on the cross sections are derived from the original topography and may not match the Global GDEM topography used on the redrafted geologic map of this report.
Dynamics of marsh-derived sediments in lagoon-type estuaries
Released October 13, 2020 09:59 EST
2020, Journal of Geophysical Research
Carmine Donatelli, Tarandeep S. Kalra, Sergio Fagherazzi, Xoaohe Zhang, Nicoletta Leonardi
Salt marshes are valuable ecosystems that must trap sediments and accrete in order to counteract the deleterious effect of sea‐level rise. Previous studies have shown that the capacity of marshes to build up vertically depends on both autogenous and exogenous processes including eco‐geomorphic feedbacks and sediment supply from in‐land and coastal ocean. There have been numerous efforts to quantify the role played by the sediments coming from marsh edge erosion on the resistance of salt marshes to sea‐level rise. However, the majority of existing studies investigating the interplay between lateral and vertical dynamics use simplified modelling approaches and they do not consider that marsh retreat can affect the regional scale hydrodynamics and sediment retention in back‐barrier basins.
In this study, we evaluated the fate of the sediments originating from marsh lateral loss by using high‐resolution numerical model simulations of Jamaica Bay, a small lagoonal estuary located in New York City. Our findings show that up to 42% of the sediments released during marsh edge erosion deposits on the shallow areas of the basin and over the vegetated marsh platforms, contributing positively to the sediment budget of the remaining salt marshes. Furthermore, we demonstrate that with the present‐day sediment supply from the ocean the system cannot keep pace with sea‐level rise even accounting for the sediment liberated in the bay through marsh degradation. Our study highlights the relevance of multiple sediment sources for the maintenance of the marsh complex.
Surficial geologic map of the Spirit Mountain SE and part of the Spirit Mountain NE 7.5' quadrangles, Nevada and Arizona
Released October 13, 2020 08:37 EST
2020, Scientific Investigations Map 3448
P. Kyle House, Ryan S. Crow, Philip A Pearthree, Amy L. Brock-Hon, Jonathan Schwing, Jacob O. Thacker, Brian F. Gootee
This geologic map includes a trove of stratigraphic and geomorphic information that chronicles the inception and evolution of the lower Colorado River. The map area is located near the south end of the Lake Mead National Recreation Area about 80 km (50 mi) downstream from Hoover Dam. It spans parts of northwestern Arizona and southern Nevada near the south end of Cottonwood Valley. The map includes the Spirit Mountain SE 7.5' quadrangle and the southern part of the Spirit Mountain NE 7.5' quadrangle. The map area contains well-exposed Neogene and Quaternary strata and associated geomorphic features that record and are critical in dating the arrival of the Colorado River in the early Pliocene and the subsequent history of the river and its landscape through the Holocene. The valley is bounded on the west by the Newberry Mountains (Nevada) and on the east by the Black Mountains (Arizona) and includes part of Lake Mohave, a reservoir created by the completion of Davis Dam in 1951. This map does not include the geology of the reservoir floor and focuses only on surficial deposits.
Challenges in the interpretation of anticoagulant rodenticide residues and toxicity in predatory and scavenging birds
Released October 13, 2020 07:00 EST
2020, Pest Management Science
Barnett A. Rattner, Joel James Harvey
Anticoagulant rodenticides (ARs) are part of the near billion-dollar rodenticide industry. Numerous studies have documented the presence of ARs in non-target wildlife, with evidence of repeated exposure to second-generation ARs. While birds are generally less sensitive to ARs than target rodent species, in some locations predatory and scavenging birds are exposed by consumption of such poisoned prey, and depending on dose and frequency of exposure, exhibit signs of intoxication that can result in death. Evidence of hemorrhage in conjunction with summed hepatic AR residues >0.1 to 0.2 mg/kg liver wet weight are often used as criteria to diagnose ARs as the likely cause of death. In this review focusing on birds of prey and scavengers, we discuss AR potency, coagulopathy, toxicokinetics and long-lasting effects of residues, the role of nutrition and vitamin K status on toxicity, and identify some research needs. A more complete understanding of the factors affecting AR toxicity in non-target wildlife would enable regulators and natural resource managers to better predict and even mitigate risk.
Four-dimensional thermal evolution of the East African Orogen: Accessory phase petrochronology of crustal profiles through the Tanzanian Craton and Mozambique Belt, northeastern Tanzania
Released October 09, 2020 10:39 EST
2020, Contributions to Mineralogy and Petrology (175)
Francisco E. Apen, Roberta L. Rudnick, John M. Cottle, Andrew R.C. Kylander-Clark, Madalyn S. Blondes, Phil Piccoli, Gareth Seward
U–Pb petrochronology of deep crustal xenoliths and outcrops across northeastern Tanzania track the thermal evolution of the Mozambique Belt and Tanzanian Craton following the Neoproterozoic East African Orogeny (EAO) and subsequent Neogene rifting. At the craton margin, the upper–middle crust record thermal quiescence since the Archean (2.8–2.5 Ga zircon, rutile, and apatite in granite and amphibolite xenoliths). The lower crust of the craton documents thermal pulses associated with Neoarchean ultra-high temperature metamorphism (ca. 2.64 Ga, > 900 °C zircon), the EAO (600–500 Ma rutile), and fluid influx during rifting (< 5 Ma apatite). Rutile in garnet granulite xenoliths exhibits partial Pb loss related to slow cooling of the lower crust after the EAO and suggests residence at 500–600 °C prior to entrainment. In contrast to the craton, the entire crust of the Mozambique Belt underwent differential cooling following the EAO. Both the upper and middle crust record metamorphism from 640 to 560 Ma (zircon, monazite, and titanite) and rapid exhumation at 510–440 Ma (rutile and apatite). Lower crustal xenoliths contain Archean zircon, but near-zero age rutile and apatite, indicating residence > 650 °C (above Pb closure of rutile and apatite) at the time of eruption. Zoned titanite records growth during cooling of the lower crust at 550 Ma, followed by fluid influx during slow cooling and exhumation (0.1–1 °C/Myr after 450 Ma). Permissible lower-crustal temperatures for the craton and orogen suggest variable mantle heat flow through the crust and reflect differences in mantle lithosphere thickness rather than advective heating from rifting.
Determining habitat limitations of Maumee River walleye production to western Lake Erie fish stocks: Documenting a spawning ground barrier
Released October 09, 2020 08:22 EST
2020, Journal of Great Lakes Research
Brian Schmidt, Taaja Tucker, Jessica Collier, Christine Mayer, Edward F. Roseman, Wendylee Stott, Jeremy J. Pritt
Tributaries provide spawning habitat for three of four major sub-stocks of Lake Erie walleye (Sander vitreus). Despite anthropogenic degradation and the extirpation of other potamodromous species, the Maumee River, Ohio, USA continues to support one of the largest fish migrations in the Laurentian Great Lakes. To determine if spawning habitat availability and quality could limit production of Maumee River walleye, two habitat suitability models were created for the lower 51 km of the Maumee River and the distribution and numbers of walleye eggs deposited in a 25 km stretch of river were assessed. Walleye eggs were collected using a diaphragm pump at 7 and 10 sites from March/April to May 2014 and 2015. The habitat suitability models showed that <3% of the river yielded ‘good’ walleye spawning habitat and 11–38% yielded ‘moderate’ walleye spawning habitat, depending on the model. However, a large set of rapids at river kilometer 28 and more than five river kilometers of less suitable habitat separated areas of ‘good’ habitat. The rapids may present a migratory barrier for many spawning walleye, as modeled water velocities exceed maximum estimated walleye swim speeds 71–100% of days during pre-spawn migration and spawning during the study period. In both study years, there was a sharp decline in mean egg numbers from spawning sites downstream of the rapids (439.7 eggs/2 min tow ± 990.6 SD) to upstream sites (5.9 eggs/2 min tow ± 19.4 SD). Physical barriers like rapids may reduce spawning habitat connectivity and could limit walleye production in the Maumee River.
Estimating the net costs of brine production and disposal to expand pressure-limited dynamic capacity for basin-scale CO2 storage in a saline formation
Released October 09, 2020 07:39 EST
2020, International Journal of Greenhouse Gas Control (102)
Steven T. Anderson, Hossein Jahediesfanjani
Micro-geographic variation in burrow use of Agassiz’s desert tortoises in the Sonoran Desert of California
Released October 09, 2020 07:22 EST
2020, The Herpetological Journal (30) 177-188
Kristy L. Cummings, Jeffrey E. Lovich, Shellie R. Puffer, Terence R. Arundel, Kathleen D. Brundige
Little has been published regarding the burrowing habits of Agassiz’s desert tortoises (Gopherus agassizii) in the Sonoran Desert of California. We monitored the interactions of tortoises with their burrows, and other tortoises, via radio-telemetry at two nearby sites between the Cottonwood and Orocopia Mountains, from 2015-2018. We examined how annual cycles of drought and non-drought years, behaviourally affected how tortoises use their burrows (i.e., burrow fidelity, cohabitation,
Four decades of land-cover change on the Kenai Peninsula, Alaska: Detecting disturbance-influenced vegetation shifts using landsat legacy data
and location), including the timing of the tortoise brumation period. Burrow locations were strongly dependent on local geology and topography, with a tendency to orientate in conformance with the general aspect of the landscape. The timing of brumation was similar to records for G. agassizii throughout their range (with a few exceptions). There was no difference in the estimated number of burrows used per 30 days between the active seasons (2017 and 2018) at the Orocopia site, despite the occurrence of drought in 2018.
Released October 09, 2020 06:45 EST
2020, Land (9)
Carson Baughman, Rachel A. Loehman, Dawn R. Magness, Lisa Saperstein, Rosemary L. Sherriff
Across Alaska’s Kenai Peninsula, disturbance events have removed large areas of forest over the last half century. Simultaneously, succession and landscape evolution have facilitated forest regrowth and expansion. Detecting forest loss within known pulse disturbance events is often straightforward given that reduction in tree cover is a readily detectable and measurable land-cover change. Land-cover change is more difficult to quantify when disturbance events are unknown, remote, or environmental response is slow in relation to human observation. While disturbance events and related land-cover change are relatively instant, assessing patterns of post-disturbance succession requires long term monitoring. Here, we describe a method for classifying land cover and quantifying land-cover change over time, using Landsat legacy imagery for three historical eras on the western Kenai Peninsula: 1973–2002, 2002–2017, and 1973–2017. Scenes from numerous Landsat sensors, including summer and winter seasons, were acquired between 1973 and 2017 and used to classify vegetation cover using a random forest classifier. Land-cover type was summarized by era and combined to produce a dataset capturing spatially explicit land-cover change at a moderate 30-m resolution. Our results document large-scale forest loss across the study area that can be attributed to known disturbance events including beetle kill and wildfire. Despite numerous and extensive disturbances resulting in forest loss, we estimate that the study area has experienced net forest gain over the duration of our study period due to reforestation within large fire events that predate this study. Transition between forest and graminoid non-forest land cover including wetlands and herbaceous uplands is the most common land-cover change—representing recruitment of a graminoid dominated understory following forest loss and the return of forest canopy given sufficient time post-disturbance.
Assessment of undiscovered conventional oil and gas resources of Southeast Asia, 2020
Released October 08, 2020 13:40 EST
2020, Fact Sheet 2020-3046
Christopher J. Schenk, Tracey J. Mercier, Cheryl A. Woodall, Thomas M. Finn, Phuong A. Le, Kristen R. Marra, Heidi M. Leathers-Miller, Ronald M. Drake II
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 10.5 billion barrels of oil and 271.5 trillion cubic feet of gas within 33 geologic provinces of Southeast Asia.
Patterns and isotopic composition of greenhouse gases under ice in lakes of interior Alaska
Released October 08, 2020 10:20 EST
2020, Environmental Research Letters (15)
Madeline O'Dwyer, David Butman, Robert G. Striegl, Mark M. Dornblaser, Kimberly P. Wickland, Catherine D. Kuhn, Matthew J. Bogard
Geologic map of the greater Portland metropolitan area and surrounding region, Oregon and Washington
Arctic and boreal lake greenhouse gas emissions (GHG) are an important component of regional carbon (C) budgets. Yet the magnitude and seasonal patterns of lake GHG emissions are poorly constrained, because sampling is limited in these remote landscapes, particularly during winter and shoulder seasons. To better define patterns of under ice GHG content (and emissions potential at spring thaw), we surveyed carbon dioxide (CO2) and methane (CH4) concentrations and stable isotopic composition during winter of 2017 in 13 lakes in the arid Yukon Flats Basin of interior Alaska, USA. Partial pressures of CO2 and CH4 ranged over three orders of magnitude, were positively correlated, and CO2 exceeded CH4 at all but one site. Shallow, organic matter-rich lakes located at lower elevations tended to have the highest concentrations of both gases, though CH4 content was more heterogeneous and only abundant in oxygen-depleted lakes, while CO2 was negatively correlated to oxygen content. Isotopic values of CO2 spanned a narrow range (−10‰ to −23‰) compared to CH4, which ranged over 50‰ (−19‰ to −71‰), indicating CH4 source pathways and sink strength varied widely between lakes. Miller-Tans and Keeling plots qualitatively suggested two groups of lakes were present; one with isotopically enriched source CH4 possibly more dominated by acetoclastic methanogenesis, and one with depleted signatures suggesting a dominance of the hydrogenotrophic production. Overall, regional lake differences in winter under ice GHG content appear to track landscape position, oxygen, and organic matter content and composition, causing patterns to vary widely even within a relatively small geographic area of interior Alaska.
Released October 08, 2020 09:21 EST
2020, Scientific Investigations Map 3443
Ray Wells, Ralph A. Haugerud, Alan R. Niem, Wendy A. Niem, Lina Ma, Russell C. Evarts, Jim E. O'Connor, Ian P. Madin, David R. Sherrod, Marvin H. Beeson, Terry L. Tolan, Karen L. Wheeler, William B. Hanson, Michael G. Sawlan
The Portland-Vancouver-Hillsboro Metropolitan Area (metro area) has great scenic, natural, and cultural resources and is the major economic hub of Oregon. The metro area is subject to a variety of geologic hazards. Underthrusting of the oceanic plate along the Cascadia plate boundary fault, or megathrust, deforms the leading edge of North America and produces earthquakes on the megathrust and in the overlying plate. Rising magma from the deeper parts of the subduction zone produces active volcanoes that form the Cascades Arc, including Mount Hood and Mount St. Helens visible from Portland. Both volcanism and strong ground-shaking from earthquakes have impacted the metro area, most recently in the 1980 eruptions of Mount St. Helens and the 1993 magnitude (M) 5.7 Scotts Mills earthquake. Great offshore earthquakes as large as M 9 on the Cascadia megathrust have shaken the metro area every 500 years or so, most recently in 1700. Giant floods have inundated the metro area, from the ice age Missoula floods about 20,000 to 15,000 years ago to the flood generated by collapse of the Bridge of the Gods landslide dam on the Columbia River around 1421–1447 A.D.
Geologic resources of the metro area include the southern part of the Mist Natural Gas Storage Field in the northwest corner of the map area, the Columbia South Shore Well Field aquifer in the Portland Basin, the Columbia River Basalt aquifer of the Tualatin Basin, and the Tualatin Basin Aquifer Storage and Recovery projects. The metro area includes several well-known American Viticultural Areas in the western part of the map area and numerous transportation, electrical transmission, and pipeline corridors.
We created this map to provide a uniform, modern geologic database for the greater Portland metro area to better understand its tectonic setting, active faults, volcanoes, landslide hazards, and distribution of geologic materials and resources. Information in this database will be used to improve seismic hazard and resource assessments in this economically important region.
A latent process model approach to improve the utility of indicator species
Released October 08, 2020 07:35 EST
Jillian Elizabeth Fleming, Chris Sutherland, Sean C Sterrett, Evan H. Campbell Grant
Bathymetry of Deadmans Lake, Golf Course Reservoir 9, Ice Lake, Kettle Lakes 1–3, and Non-Potable Reservoirs 1–4 at the U.S. Air Force Academy, Colorado, 2019
The state of an ecosystem is governed by dynamic biotic and abiotic processes, which can only be partially observed. Costs associated with measuring each component limit the feasibility of comprehensive assessments of target ecosystems. Instead, indicator species are recommended as a surrogate index. While this is an attractive concept, indicator species have rarely proven to be an effective tool for monitoring ecosystems and informing management decisions. One deficiency in the existing theoretical development of indicator species may be overcome with the incorporation of latent (i.e. unobservable) states. Advancements in quantitative ecological models allow for latent‐state models to be tested empirically, facilitating the robust evaluation and practical use of indicator species for ecosystem science and management. Here, we extend the existing conceptual models of indicator species to include a direct relationship between an indicator species, ecosystem change drivers and latent processes and variables. Our approach includes explicit consideration of important estimation uncertainty and narrows the range of values a latent variable may take by relating it to measurable attribute(s) of an indicator species. We demonstrate the utility of this approach by relating a commonly cited indicator species, the red‐backed salamander Plethodon cinereus, to a typical latent process of interest – ecosystem health.
Released October 07, 2020 15:35 EST
2020, Scientific Investigations Map 3463
Michael S. Kohn, Laura A. Hempel
The U.S. Geological Survey, in cooperation with the U.S. Air Force Academy (USAFA), carried out bathymetric and topographic surveys to characterize the volume of Deadmans Lake, Golf Course Reservoir 9, Ice Lake, Kettle Lakes 1–3, and Non-Potable Reservoirs 1–4 at the U.S. Air Force Academy, Colorado. Bathymetric maps of each lake and reservoir are presented with figures of the elevation-volume curves. The bathymetric surveys were carried out from October 15, 2019, to December 12, 2019, using a manually operated, boat-mounted, single-beam echo sounder integrated with a Real-Time Kinematic Global Navigation Satellite Systems receiver. Topographic surveys were carried out during the same time period using Real-Time Kinematic Global Navigation Satellite System to collect elevation data at and above the water surface and up to the elevation of the dam or spillway at the time of the surveys. The topographic and bathymetric datasets were imported into Esri ArcMap 10.7.1. The combined survey points were then interpolated into digital elevation models, which were used to determine lake or reservoir volumes that correspond to water-surface elevations between the lakebed and the approximate top of the dam or spillway.
This report provides an updated characterization of storage capacity and improved understanding of present (2019) water capacity in the lakes and reservoirs at the USAFA. In addition, these surveys serve as a baseline that could be compared with future surveys of the lakes and reservoirs. The differences in these and future surveys could then be used to determine sedimentation infill rates and provide estimates of the lifespan of the lakes and reservoirs.
Development of a suite of functional immune assays and initial assessment of their utility in wild smallmouth bass health assessments
Released October 07, 2020 10:05 EST
2020, Open-File Report 2020-1077
Cheyenne R. Smith, Christopher A. Ottinger, Heather L. Walsh, Vicki S. Blazer
Methods were developed for measuring immune function in Micropterus dolomieu (smallmouth bass). The ultimate objective is to monitor and evaluate changes over time in immune status and disease resistance in conjunction with other characteristics of fish health and environmental stressors. To test these methods for utility in ecotoxicological studies, 192 smallmouth bass, age 2 years and older, were collected from three sites within the Susquehanna River Basin and one site in the Ohio River Basin during spring and fall 2016 and 2017. The anterior kidney was aseptically removed and homogenized for leukocyte isolation. Leukocytes were tested for bactericidal activity against two species of bacteria; respiratory burst activity when stimulated with phorbol 12-myristate 13-acetate; and mitogenesis activity when stimulated with concanavalin A, phytohemagglutinin, and lipopolysaccharide. Tissues were preserved for histopathological analyses.
Two of the sites were part of a monitoring program at which surface-water samples were collected monthly (bimonthly in spring) for chemical contaminants. Significant seasonal and (or) site differences in all three immune function tests were observed. Interpretations of seasonal trends in immune function of wild fish or correlations with environmental variables and other factors are difficult to make owing to the complex nature of the immune response and the environment. Differences in immune function could potentially be related to a variety of confounding factors; therefore, additional endpoints and repeated sampling over an extended period are essential to draw conclusions on the immune status of wild fish.
Localized fault-zone dilatancy and surface inelasticity of the 2019 Ridgecrest earthquakes
Released October 07, 2020 07:58 EST
2020, Nature Geoscience (13) 699-704
William D. Barnhart, Ryan D. Gold, James Hollingsworth
Earthquakes produce a spectrum of elastic and inelastic deformation processes that are reflected across various length and time scales. While elasticity has long dominated research assumptions in active tectonics, increasing interest has focused on the inelastic characteristics of earthquakes, particularly those of the surface fault rupture zone itself, and how they relate to ground rupture hazard and the mechanics of damage zones. Here we present detailed co-seismic surface-strain analysis of the 2019 Ridgecrest, California, earthquakes. We derive three-dimensional high-resolution surface displacements from satellite optical imagery, which we then invert for the co-seismic surface-strain tensors. We show that fault-zone dilation is pervasive throughout these earthquakes and that inelastic failure is present but relatively localized (median width of 31 m). The width of the inelastic failure zone is not correlated to off-fault deformation, surface geology or displacement magnitude. Instead, the extent and kinematics of inelastic failure reflect active, mylonitic deformation of the fault damage zone that is influenced by rupture velocity and fault maturity. These results highlight how a single earthquake contributes to the long-term, permanent geologic record of faulting.
A novel approach for next generation water use mapping using Landsat and Sentinel-2 satellite data
Released October 07, 2020 07:27 EST
2020, Hydrological Sciences Journal
Ramesh Singh, Kul Bikram Khand, Stefanie Kagone, Matthew Schauer, Gabriel Senay, Zhuoting Wu
Spatiotemporal pattern of interactions between an apex predator and sympatric species
Evapotranspiration (ET) is needed in a range of applications in hydrology, climatology, ecology, and agriculture. Remote sensing-based estimation is the only viable and economical method for ET estimation over large areas. The current Landsat satellites provide images every 16 days limiting the ability to capture biophysical changes affecting ET. Thus, we explored the potential integration of Landsat 8 and Sentinel-2 data for estimating ET using a surface energy balance model. The results indicate the proposed Landsat-Sentinel data fusion approach substantially reduced relative errors from 48% to 10% on area-wide and from 49% to 17% on pixel-wide compared to linear interpolation between two Landsat images. The proposed approach had a better agreement with expected actual ET maps across high-vegetation conditions than in low-vegetation conditions. The finer temporal resolution and better accuracy of ET maps based on Landsat-Sentinel integration is of great importance in managing limited water resources.
Released October 07, 2020 07:04 EST
2020, Journal of Mammology
Marta P Guitart, David P Onorato, James E. Hines, Madan K. Oli
Increases in apex predator abundance can influence the behavior of sympatric species, particularly when the available habitat and/or resources are limited. We assessed the temporal and spatiotemporal interactions between Florida panthers (Puma concolor coryi) and six focal sympatric species in South Florida, where Florida panther abundance has increased by more than 6-fold since the 1990’s. Using camera trap data, we quantified species’ diel activity patterns, temporal overlap, and time-to-encounter (i.e., time between consecutive visits of a Florida panther and a focal species and vice versa). The Florida panther and bobcat (Lynx rufus) displayed a nocturnal activity pattern; the black bear (Ursus americanus), white-tailed deer (Odocoileus virginianus), wild boar (Sus scrofa), and wild turkey (Meleagris gallopavo) were mostly diurnal; and the raccoon (Procyon lotor) was cathemeral. Prey species and black bears minimized encounters with Florida panthers by being active during the day and displaying longer time-to-encounter, whereas Florida panthers visited a site after a prey species at higher probabilities than after competitor species, and were more likely to visit an elevated site or upland habitat. Our results suggest that interactions between Florida panthers and sympatric species in our study system are driven by species-specific behavioral responses. Gaining a better understanding of the crucial interactions driving species coexistence is important for a better understanding of the structure and function of ecological communities and help manage the potential expansion of the Florida panther into Central Florida.
Estimating flood magnitude and frequency on streams and rivers in Connecticut, based on data through water year 2015
Released October 06, 2020 16:00 EST
2020, Scientific Investigations Report 2020-5054
Elizabeth A. Ahearn, Glenn A. Hodgkins
The U.S. Geological Survey, in cooperation with the Connecticut Department of Transportation, updated flood-frequency estimates with 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities (2-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year recurrence intervals, respectively) for 141 streamgages in Connecticut and 11 streamgages in adjacent States using annual peak-flow data through water year 2015. Peak-flow regression equations were derived for estimating flows at ungaged stream sites with annual exceedance probabilities from 50 to 0.2 percent. Methods for estimating prediction intervals for the peak-flow regression equations are presented. The regression equations are applicable for basins in Connecticut with drainage areas ranging from 0.69 to 325 square miles that are not affected by flood-control regulation or flow diversions.
The flood discharges for select annual exceedance probabilities were estimated following new (2018) national guidelines for flood-frequency analyses. New guidelines have improved statistical methods for flood-frequency analysis including (1) the expected moments algorithm to help describe uncertainty in annual peak flows and to better represent missing and historical record and (2) the generalized multiple Grubbs-Beck test to screen out potentially influential low outliers and to better fit the upper end of the peak-flow distribution. Additionally, a new regional skew (0.37) derived for New England was used in the flood-frequency analysis for the streamgages.
Annual peak flows were analyzed for trends for four time periods (30, 50, 70, and 90 years) through 2015. Trend results show some statistical evidence of increasing peak flows in each of the time periods analyzed; however, multidecadal climate cycles may be influencing the number and magnitude of the trends. Historical peak-flow trends in and near Connecticut do not offer clear and convincing evidence for incorporating trends into flood-frequency analyses. For this study, the traditional assumption of stationarity is used with no adjustment for trends.
Generalized least squares regression techniques were used to develop the final set of multivariable regression equations for estimating flood discharges with 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities. The standard error of prediction for the regional regression equations ranged from 26.3 to 45.0 percent. The standard error of prediction was slightly smaller in the current study compared to the 2004 study, indicating an improvement in the predictive ability of the equations (6 percent smaller at the 50-percent annual exceedance probability to about 1 percent smaller at the 1-percent annual exceedance probability). Generalized least squares regression techniques also were used to develop a one-variable (drainage-area-only) equation. Drainage-area-only equations can be used as an alternative to the multiexplanatory variable statewide regression equations if decreased accuracy is acceptable.
The revised statistical procedures and additional streamgage data applied in the current study result in a more accurate representation of peak-flow conditions in Connecticut than was previously available. The regional regression equations will be integrated in the U.S. Geological Survey StreamStats program, which estimates basin and climatic characteristics and streamflow statistics at user-selected ungaged stream sites.
Transmissivity estimated from brief aquifer tests of domestic wells and compared with bedrock lithofacies and position on hillsides in the Appalachian Plateau of New York
Released October 06, 2020 15:30 EST
2020, Scientific Investigations Report 2020-5087
Allan D. Randall, Andrew C. Mills
Procedures for undertaking and analyzing recovery from aquifer tests of 13 to 132 seconds (described in reports cited herein) were applied to 51 domestic drilled wells that penetrated bedrock outside major valleys in the part of the Appalachian Plateau of New York drained by the Susquehanna River. Transmissivities calculated from these tests ranged over three orders of magnitude in both the Catskill-Cattaraugus lithofacies (shales, mudstones, siltstones, medium to coarse sandstones, pebbly sandstones) and the Chemung-Hamilton lithofacies (shales, mudstones, siltstones, fine to medium sandstones). Median transmissivity values were 0.000425 foot squared per second (36.7 feet squared per day) in the Catskill-Cattaraugus lithofacies and 0.00055 foot squared per second (47.5 feet squared per day) in the Chemung-Hamilton lithofacies. The distributions of transmissivity values within the two lithofacies were likewise similar. The range and median values of transmissivity were also nearly the same on lower and midlevel hillsides and were only slightly greater on a few upper hillsides. Transmissivities estimated from such easily arranged and analyzed tests may be appropriate for estimating groundwater flux under the small gradients that prevail under natural conditions, but not under larger drawdowns and steeper gradients near clusters of domestic wells. Four of the 51 wells tested were also pumped for 10 to 32 minutes; analysis by the Theis recovery method yielded transmissivities consistent with the brief tests for 2 wells, but 7 to 9 times smaller for 2 wells.
Transmissivity values estimated by the PICKINGmodel were not significantly different from values estimated by an automated application of the Picking method (PPC-Recovery) at a probability of 95 percent. Transmissivities calculated by either method from data for time intervals of 120 seconds or less may be of limited practical value because they apply only to a small volume of bedrock close to the pumped well.
A clarification on the effects of urbanization on Golden Eagle (Aquila chrysaetos) habitat selection
Released October 06, 2020 11:38 EST
2020, Open-File Report 2020-1110
Jeff A. Tracey, Melanie C. Madden, Peter H. Bloom, Robert N. Fisher
In 2018, the U.S. Geological Survey (USGS) published an Open-File Report (Tracey and others, 2018) presenting a Bayesian habitat selection model for golden eagles (Aquila chrysaetos) in San Diego County, California. The model used telemetry data to examine the effects of urban development, exurban development, and topography (characterized by a topographic position index and a vector ruggedness measure, TPI and VRM respectively) on golden eagle habitat selection probability. Based on figures 3 and 6 of Tracey and others (2018), we received inquiries from cooperators (U.S. Fish and Wildlife Service and California Department of Fish and Wildlife) about how the probability of eagle use declines with decreasing distance to the urban edge. Here, we clarify our results by addressing that question.
Identifying the greatest earthquakes of the past 2000 years at the Nehalem River Estuary, Northern Oregon Coast, USA
Released October 06, 2020 11:16 EST
2020, Open Quaternary (6) 1-30
Alan R. Nelson, Andrea D. Hawkes, Yuki Sawai, Simon E. Engelhart, Robert C. Witter, Wendy C. Grant-Walter, Lee-Ann Bradley, Tina Dura, Niamh Cahill, Benajamin P. Horton
We infer a history of three great megathrust earthquakes during the past 2000 years at the Nehalem River estuary based on the lateral extent of sharp (≤3 mm) peat-mud stratigraphic contacts in cores and outcrops, coseismic subsidence as interpreted from fossil diatom assemblages and reconstructed with foraminiferal assemblages using a Bayesian transfer function, and regional correlation of 14C-modeled ages for the times of subsidence. A subsidence contact from 1700 CE (contact A), sometimes overlain by tsunami-deposited sand, can be traced over distances of 7 km. Contacts B and D, which record subsidence during two earlier megathrust earthquakes, are much less extensive but are traced across a 700-m by 270-m tidal marsh. Although some other Cascadia studies report evidence for an earthquake between contacts B and D, our lack of extensive evidence for such an earthquake may result from the complexities of preserving identifiable evidence of it in the rapidly shifting shoreline environments of the lower river and bay. Ages (95% intervals) and subsidence for contacts are: A, 1700 CE (1.1 ± 0.5 m); B, 942–764 cal a BP (0.7 ± 0.4 m and 1.0 m ± 0.4 m); and D, 1568–1361 cal a BP (1.0 m ± 0.4 m). Comparisons of contact subsidence and the degree of overlap of their modeled ages with ages for other Cascadia sites are consistent with megathrust ruptures many hundreds of kilometers long. But these data cannot conclusively distinguish among different types or lengths of ruptures recorded by the three great earthquake contacts at the Nehalem River estuary.
The eruptive history, magmatic evolution, and influence of glacial ice at long-lived Akutan volcano, eastern Aleutian Islands, Alaska, USA
Released October 06, 2020 08:49 EST
2020, GSA Bulletin
Michelle L. Coombs, Brian Jicha
New 40Ar/39Ar and whole-rock geochemical data are used to develop a detailed eruptive chronology for Akutan volcano, Akutan Island, Alaska, USA, in the eastern Aleutian island arc. Akutan Island (166°W, 54.1°N) is the site of long-lived volcanism and the entire island comprises volcanic rocks as old as 3.3 Ma. Our current study is on the 225 km2 western half of the island, where our results show that the focus of volcanism has shifted over the last ∼700 k.y., and that on occasion, multiple volcanic centers have been active over the same period, including within the Holocene. Incremental heating experiments resulted in 56 40Ar/39Ar plateau ages and span 2.3 Ma to 9.2 ka.
Eruptive products of all units are primarily tholeiitic and medium-K, and range from basalt to dacite. Rare calc-alkaline lavas show evidence suggesting their formation via mixing of mafic and evolved magmas, not via crystallization-derived differentiation through the calc-alkaline trend. Earliest lavas are broadly dispersed and are almost exclusively mafic with high and variable La/Yb ratios that are likely the result of low degrees of partial mantle melting. Holocene lavas all fall along a single tholeiitic, basalt-to-dacite evolutionary trend and have among the lowest La/Yb ratios, which favors higher degrees of mantle melting and is consistent with the increased magma flux during this time. A suite of xenoliths, spanning a wide range of compositions, are found in the deposits of the 1.6 ka caldera-forming eruption. They are interpreted to represent completely crystallized liquids or the crystal residuum from tholeiitic fractional crystallization of the active Akutan magma system.
The new geochronologic and geochemical data are used along with existing geodetic and seismic interpretations from the island to develop a conceptual model of the active Akutan magma system. Collectively, these data are consistent with hot, dry magmas that are likely stored at 5−10 km depth prior to eruption. The prolonged eruptive activity at Akutan has also allowed us to evaluate patterns in lava-ice interactions through time as our new data and observations suggest that the influence of glaciation on eruptive activity, and possible magma composition, is more pronounced at Akutan than has been observed for other well-studied Aleutian volcanoes to the west.
Water balance as an indicator of natural resource condition: Case studies from Great Sand Dunes National Park and Preserve
Released October 06, 2020 07:53 EST
2020, Global Ecology and Conservation (24)
David P. Thoma, Michael T. Tercek, E. William Schweiger, Seth M. Munson, John E. Gross, S. Tom Olliff
Spatially explicit reconstruction of post-megafire forest recovery through landscape modeling
Released October 06, 2020 07:44 EST
2020, Environmental Modelling and Software (134)
Wenru Xu, Hong He, Jacob S. Fraser, Todd J. Hawbaker, Paul D. Henne, Shengwu Duan, Zhiliang Zhu
The effects of management practices on grassland birds—Brewer’s Sparrow (Spizella breweri breweri)
Released October 06, 2020 06:39 EST
2020, Professional Paper 1842-AA
Brett L. Walker, Lawrence D. Igl, Jill A. Shaffer
Keys to Brewer’s Sparrow (Spizella breweri breweri) management include maintaining extensive, unfragmented patches of suitable breeding habitat; reducing conifer cover and height; preventing the invasion of conifers and nonnative plants, especially cheatgrass (downy brome [Bromus tectorum]); minimizing disturbance to soil; and restricting the use of pesticides and herbicides during the breeding season (April–July). Brewer’s Sparrows have been reported to use breeding habitats with 12–170 centimeter (cm) vegetation height, 2–34 cm visual obstruction reading, 1–74 percent grass cover, less than (<) 19 percent forb cover, 1–65 percent shrub cover, 1–75 percent bare ground, 2–61 percent litter cover, and <1 cm litter depth. During post-fledging dispersal in July, Brewer’s Sparrow adults and young may shift habitat use to nearby aspen (Populus species [spp.]), riparian shrub, or deciduous mountain shrub habitats, so these habitats also may be important for management.
Can oceanic prey effects on growth and time to fledging mediate terrestrial predator limitation of an at‐risk seabird?
Released October 05, 2020 11:28 EST
2020, Ecosphere (11)
Timothy Knudson, James R. Lovvorn, M. James Lawonn, Robin Corcoran, Dan Roby, John F. Piatt, William Pyle
Most seabird species nest colonially on cliffs or islands with limited terrestrial predation, so that oceanic effects on the quality or quantity of prey fed to chicks more often determine nest success. However, when predator access increases, impacts can be dramatic, especially when exposure to predators is extended due to slow growth from inadequate food. Kittlitz’s Murrelet (Brachyramphus brevirostris), a rare seabird having experienced serious declines, nests solitarily on the ground in barren, often alpine areas where exposure to predators is generally low. Nestling growth rates are exceptionally high and nestling periods very short relative to other Alcidae. This strategy reduces duration of exposure to predators, but demands adequate deliveries of high‐energy prey. In an area where foxes can access nests, we investigated whether varying energy content of prey fed to chicks could alter growth rates and resulting duration of predator exposure, and whether prolonged exposure appreciably reduced nest success. From 2009 to 2016, we monitored 139 nests; 49% were depredated (almost all by foxes) and 25% fledged. Prey fed to nestlings were 80% Pacific sand lance (Ammodytes personatus) and 19% capelin (Mallotus villosus), with capelin having 2.3× higher energy content per fish. In a year of slow chick growth, increased sand lance energy density of 31% (4.29–5.64 kJ/g, within published values), or increased proportion of capelin in the diet from 5.6% to 27.2%, would have allowed maximum chick growth. Maximum growth rates were attainable by delivering only 1.9 capelin/d versus 5.5 sand lance/d. Slow growth increased time to fledging by up to 5 d, decreasing survival by 7.7% (0.142–0.131). Breeding propensity of Kittlitz’s Murrelet averages only 20%, so even small changes in nest success could affect populations. Although nest success was limited mainly by predation, oceanic effects on prey quantity and quality had overriding impacts in one year (2015 heat wave), and small but substantive effects in other years by mediating exposure to predation. Climate warming that decreases availability of high‐energy forage fish, or increases expansion of predators into nesting habitats, may disproportionately affect this sensitive species and others with predator‐accessible nests and demands for energy‐rich prey.
Examination of inertinite within immature Eagle Ford Shale at the nanometer-scale using atomic force microscopy-based infrared spectroscopy
Released October 05, 2020 08:24 EST
2020, International Journal of Coal Geology
Aaron M. Jubb, Paul C. Hackley, Justin E. Birdwell, Javin J. Hatcherian, Jing Qu
The nanoscale molecular composition of sedimentary organic matter is challenging to characterize in situ given the limited tools available that can adequately interrogate its complex chemical structure. This is a particularly relevant issue in source rocks, as kerogen composition will strongly impact its reactivity and so is critical to understanding petroleum generation processes during catagenesis. The recent advent of tip-enhanced analytical methods, such as atomic force microscopy-based infrared spectroscopy (AFM-IR), has allowed for the major compositional features of kerogen and other types of in situ organic matter to be elucidated at spatial resolutions at or below 50 nm. Here AFM-IR was applied to examine inertinite, an important organic matter type, present in a thermally immature Eagle Ford calcareous mudstone. The data show that the nanoscale molecular composition of the examined inertinite is (i) less heterogeneous than solid bitumen in more thermally mature Eagle Ford samples and (ii) more hydrogen- and oxygen-rich than inertinite examined in the New Albany Shale.
Linking mesoscale meteorology with extreme landscape response: Effects of narrow cold frontal rainbands (NCFR)
Released October 04, 2020 07:23 EST
2020, Journal of Geophysical Research - Earth Surface (125)
Brian D. Collins, N. S. Oakley, Jonathan P Perkins, Amy E. East, Skye C. Corbett, Benjamin J. Hatchett
Effects of early life stage exposure of largemouth bass to atrazine or a model estrogen (17α-ethinylestradiol)
Landscapes evolve in response to prolonged and/or intense precipitation resulting from atmospheric processes at various spatial and temporal scales. Whereas synoptic (large‐scale) features (e.g., atmospheric rivers and hurricanes) govern regional‐scale hydrologic hazards such as widespread flooding, mesoscale features such as thunderstorms or squall lines are more likely to trigger localized geomorphic hazards such as landslides. Thus, to better understand relations between hydrometeorological drivers and landscape response, a knowledge of mesoscale meteorology and its impacts is needed. Here we investigate the extreme geomorphic response associated with one type of mesoscale meteorological feature, the narrow cold frontal rainband (NCFR). Resulting from low‐level convergence and shallow convection along a cold front, NCFRs are narrow bands of high‐intensity rainfall that occur in midlatitude areas of the world. Our study examines an NCFR impacting the Sierra Nevada foothills (California, USA) that initiated over 500 landslides, mobilized ~360,000 metric tons of sediment to the fluvial system (as much as 16 times the local annual sediment yield), and severely damaged local infrastructure and regional water transport facilities. Coupling geomorphological field investigations with meteorological analyses, we demonstrate that precipitation associated with the NCFR was both intense (maximum 15 min intensity of 70 mm/hr) and localized, resulting in a highly concentrated band of shallow landsliding. This meteorological phenomenon likely plays an important role in landscape evolution and hazard initiation. Other types of mesoscale meteorological features also occur globally and offer new avenues for understanding the effects of storms on landscapes.
Released October 02, 2020 11:37 EST
2020, PeerJ (8)
Jessica Kristin Leet, Catherine A. Richter, Robert S. Cornman, Jason P. Berninger, Ramji K. Bhandari, Diane K. Nicks, James L. Zajicek, Vicki S. Blazer, Donald E. Tillitt
Endocrine disrupting contaminants are of continuing concern for potentially contributing to reproductive dysfunction in largemouth and smallmouth bass in the Chesapeake Bay watershed (CBW) and elsewhere. Exposures to atrazine (ATR) have been hypothesized to have estrogenic effects on vertebrate endocrine systems. The incidence of intersex in male smallmouth bass from some regions of CBW has been correlated with ATR concentrations in water. Fish early life stages may be particularly vulnerable to ATR exposure in agricultural areas, as a spring influx of pesticides coincides with spawning and early development. Our objectives were to investigate the effects of early life stage exposure to ATR or the model estrogen 17α-ethinylestradiol (EE2) on sexual differentiation and gene expression in gonad tissue. We exposed newly hatched largemouth bass (LMB, Micropterus salmoides) from 7 to 80 days post-spawn to nominal concentrations of 1, 10, or 100 µg ATR/L or 1 or 10 ng EE2/L and monitored histological development and transcriptomic changes in gonad tissue. We observed a nearly 100% female sex ratio in LMB exposed to EE2 at 10 ng/L, presumably due to sex reversal of males. Many gonad genes were differentially expressed between sexes. Multidimensional scaling revealed clustering by gene expression of the 1 ng EE2/L and 100 µg ATR/L-treated male fish. Some pathways responsive to EE2 exposure were not sex-specific. We observed differential expression in male gonad in LMB exposed to EE2 at 1 ng/L of several genes involved in reproductive development and function, including star, cyp11a2, ddx4 (previously vasa), wnt5b, cyp1a and samhd1. Expression of star, cyp11a2 and cyp1a in males was also responsive to ATR exposure. Overall, our results confirm that early development is a sensitive window for estrogenic endocrine disruption in LMB and are consistent with the hypothesis that ATR exposure induces some estrogenic responses in the developing gonad. However, ATR-specific and EE2-specific responses were also observed.
Distribution of selected hydrogeologic characteristics of the upper glacial and Magothy aquifers, Long Island, New York
Released October 01, 2020 14:05 EST
2020, Scientific Investigations Report 2020-5023
Donald A. Walter, Jason S. Finkelstein
The Pleistocene- and Cretaceous-age sediments underlying Long Island, New York, compose an important sole-source aquifer system that is nearly 2,000 feet thick in some areas. Sediment characteristics of importance for water supply include water-transmitting properties—horizontal and vertical hydraulic conductivity—and the distribution of lignite, which provides an important control on oxygen-reduction (redox) conditions and water quality, in Cretaceous-age aquifers. Several decades of urbanization and the associated need to meet water demand have generated abundant data on the lithology of the aquifer sediments and the potential for an improved regional-scale understanding of this aquifer system. There is a range in the source and quality of the information, but large amounts of data, even of lesser quality, can yield insight into important aquifer characteristics.
The distribution of the horizontal and vertical hydraulic conductivity and the probability of occurrence of lignite and clay in the aquifer were developed for this study from a database of drilling records and geophysical logs. Lithologic descriptions were categorized into a set of standardized codes, which in turn, were aggregated into a set of general codes for the Pleistocene-age upper glacial and Cretaceous-age Magothy aquifers. General values of hydraulic conductivity were assigned to each code from published estimates on Long Island and analogous hydrogeologic environments on Cape Cod, Massachusetts. A binary value of 1 or 0 was assigned to each coded interval to indicate the presence or absence of lignite or based on keywords in the lithologic descriptions. This information was assembled into a geographic information system database that was queried sequentially and used to develop gridded values of each aquifer characteristic by use of ordinary kriging for a set of grids, each representing 10-foot-thick planar slices for the entire vertical thickness of each aquifer. These sets of grids, taken as a whole, represent a quasi-three-dimensional representation of each aquifer characteristic in both the upper glacial and Magothy aquifers.
The analysis of hydraulic conductivity shows patterns that generally reflect known depositional features of each unit and are consistent with the current understanding of the geology of the aquifers. Spatial patterns in the upper glacial aquifer show contrasts in estimated hydraulic conductivity: lower values occur in inland areas and likely are associated with glacial moraines; higher values generally occur to the south in association with glacial outwash. Higher values of hydraulic conductivity in the Magothy aquifer, which resulted from deltaic deposition, generally occur in the basal parts of the unit, are associated with channel-lag deposits and are found in parts of the aquifer known for large well yields. Lower values of hydraulic conductivity generally occur in middle parts of the aquifer associated with deposition in overbank and wetland environments. The probability of lignite occurrence is highest in this same vertical zone of the Magothy aquifer, consistent with deposition in wetland environments. The probability of lignite occurrence generally is highest along the southern shore of the island. Lignite occurrence generally is consistent with water-quality patterns; water quality in these same areas indicate chemically reducing conditions and redox-related iron biofouling commonly occurs.
Selecting three components of ground motions from Conditional Spectra for multiple stripe analyses
Released October 01, 2020 12:03 EST
2020, Conference Paper, Proceedings of the 17th World Conference on Earthquake Engineering
Neal (Simon) S Kwong, Kishor Jaiswal, Nicolas Luco, J.W. Baker
For complex structures where the seismic response depends appreciably on the vertical (V) component of ground motion (GM) (e.g., base-isolated buildings, long-span bridges, dams, nuclear power plants), incremental dynamic analysis (IDA) is commonly utilized to estimate seismic risk, where the V components of GM are selected and scaled based on the corresponding horizontal (H) components. The resulting seismic risk (e.g., fragility estimates, annual rates of failure) will likely be significantly biased when the scale factors in IDA are very large. As an alternative to IDA, multiple stripe analyses (MSA) with GMs for each stripe selected from the Conditional Spectrum (CS) can be used to estimate the seismic risk; however, the V components are still commonly selected and scaled based on the corresponding H components. Consequently, these V components may still be inconsistent relative to the corresponding target hazard, again yielding biased estimates of seismic risk. To improve the accuracy of seismic risk estimates, we extend the CS to include the V component of GM and present an approach to select multicomponent GMs that are hazard consistent with respect to all three components of GM. Using the target and the GM selection approach developed in this study, we then evaluate typical current practice for selecting and scaling V components of GM. We observe that the latter approach can yield hazard-inconsistent multicomponent GMs, but hazard consistency can be improved by including the V component in the selection process, constraining the scale factors, or widening the period range for selecting GMs.
Analyses on subpopulation abundance and annual number of maternal dens for the U.S. Fish and Wildlife Service on polar bears (Ursus maritimus) in the southern Beaufort Sea, Alaska
Released October 01, 2020 10:12 EST
2020, Open-File Report 2020-1087
Todd C. Atwood, Jeffrey F. Bromaghin, Vijay P. Patil, George M. Durner, David C. Douglas, Kristin S. Simac
The long-term persistence of polar bears (Ursus maritimus) is threatened by sea-ice loss due to climate change, which is concurrently providing an opportunity in the Arctic for increased anthropogenic activities including natural resource extraction. Mitigating the risk of those activities, which can adversely affect the population dynamics of the southern Beaufort Sea (SBS) subpopulation, is an emerging challenge as polar bears become more reliant on land and come into more frequent contact with humans. The Marine Mammal Protection Act and Endangered Species Act require the U.S. Fish and Wildlife Service to determine whether industrial activities will have a negligible impact on the SBS subpopulation. Information important to making that determination includes estimates of subpopulation abundance and the number of maternal dens likely to be present in areas where industrial activities occur. We analyzed mark-recapture data collected from SBS polar bears sampled in Alaska during 2001–16 using multistate Cormack-Jolly-Seber models. Estimated survival rates were relatively high during 2001–03, lower during 2004–08, then higher during 2009–15 except for 2012. Estimated abundance in the Alaska part of the SBS was consistent with the estimated survival rates, declining from about 1,300 bears in 2003 to 525 bears in 2006 and then remaining generally stable during 2006–15. The point estimate for the Alaska part of the SBS in 2015, the last year in which abundance could be estimated, was 573 bears (95-percent credible interval = 232, 1,140 bears). To estimate the expected number of terrestrial dens likely to be present in a given region in a given year, we used a Bayesian modeling approach based on calculations derived from SBS demographic and denning data. We estimated that the entire SBS subpopulation produced 123 dens per year (median; 95-percent credible interval = 69, 198 dens), 66 (median; 95-percent credible interval = 35, 110 dens) of which were land-based. Most land-based dens were located between the Colville and Canning Rivers (which includes the Prudhoe Bay-Kuparuk industrial footprint), followed by the 1002 Area of the Arctic National Wildlife Refuge and the National Petroleum Reserve-Alaska.
Quantifying drought’s influence on moist soil seed vegetation in California’s Central Valley through remote sensing
Released October 01, 2020 07:36 EST
2020, Bulletin of the Ecological Society of America (101)
Kristin B. Byrd, Austen Lorenz, James Anderson, Cynthia Wallace, Kara Moore-O'Leary, Jennifer Isola, Ricardo Ortega, Matt Reiter
Across the Central Valley of California, millions of wintering waterfowl rely on moist soil seed (MSS) plants that grow in managed seasonal wetlands as a critical source of food. Estimates of MSS plant production are used to set waterfowl habitat targets yet this information is not well known. We created the first Central Valley-wide time series maps of MSS plant distributions and productivity. We found that MSS plant seed yield declined in critical drought years, which corresponded with reduced water delivery to managed wetlands. Our results provide improved food resource estimates and information to help managers prioritize actions as water supply becomes more uncertain with climate change.
Photoluminescence imaging of whole zircon grains on a petrographic microscope—An underused aide for geochronologic studies
Released October 01, 2020 07:22 EST
2020, Minerals (10)
Ryan J. McAleer, Aaron M. Jubb, Paul C. Hackley, Gregory J. Walsh, Arthur J. Merschat, Sean P. Regan, William C. Burton, Jorge A. Vazquez
The refractory nature of zircon to temperature and pressure allows even a single zircon grain to preserve a rich history of magmatic, metamorphic, and hydrothermal processes. Isotopic dating of micro-domains exposed in cross-sections of zircon grains allows us to interrogate this history. Unfortunately, our ability to select the zircon grains in a heavy mineral concentrate that records the most geochronologic information is limited by our inability to predict internal zonation from observations of whole grains. Here we document the use of a petrographic microscope to observe and image the photoluminescence (PL) response of whole zircon grains excited under ultraviolet (UV) light, and the utility of this PL response in selecting grains for geochronology. While zircon fluorescence has long been known, there is limited documentation of its utility for and application to geochronologic studies. Our observations of zircon from an un-metamorphosed igneous rock, two meta-igneous rocks, and a placer deposit show that variations in the PL color are readily observable in real-time, both among grains in a population of zircons and within single grains. Analyses of cross-sections of the same grains demonstrate that the changes in PL correlate with zoning in backscattered electron (BSE) and cathodoluminescence (CL) images as well as with changes in U + Th concentration and spectroscopic proxies for radiation damage. In other words, the whole grain PL provides a low-resolution preview of the U + Th zoning expected in a cross-sectioned grain. We demonstrate the usefulness of this “preview” in identifying and selecting the subset of zircon grains in a heavy mineral separate that has metamorphic rims of sufficient width to date by secondary ionization mass spectrometry (SIMS). The data are also used to place preliminary constraints on the age and U + Th concentrations at which a yellow PL response is observed in natural samples. The PL response of zircon is well-known among spectroscopists, and these simple applications demonstrate several ways in which the response might be more effectively used by geochronologists.
Assessing the exposure of three diving bird species to offshore wind areas on the U.S. Atlantic Outer Continental Shelf using satellite telemetry
Released October 01, 2020 07:14 EST
2020, Diversity and Distributions
Iain J Stenhouse, Alicia Berlin, Andrew T Gilbert, M Wing Goodale, Carrie O Gray, William A Montevecchi, Lucas Savoy, Caleb S Spiegel
The United States Atlantic Outer Continental Shelf (OCS) has considerable offshore wind energy potential. Capturing that resource is part of a broader effort to reduce CO2 emissions. While few turbines have been constructed in U.S. waters, over a dozen currently planned offshore wind projects have the potential to displace marine birds, potentially leading to effective habitat loss. We focused on three diving birds identified in Europe to be vulnerable to displacement. Our research aimed to determine their potential exposure to areas designated or proposed for offshore wind development along the Atlantic OCS.
Satellite tracking technology was used to determine the spatial and temporal use and movement patterns of Surf Scoters (Melanitta perspicillata), Red‐throated Loons (Gavia stellata) and Northern Gannets (Morus bassanus), and calculate their exposure to each offshore wind area. We tagged 236 adults in 2012–2015 on the Atlantic OCS from New Jersey to North Carolina; an additional 147 birds tagged in previous tracking studies were integrated into our analyses. Tracking data were analysed in two‐week intervals using dynamic Brownian bridge movement models to develop composite spatial utilization distributions. For each species, these distributions were then used to calculate the spatio‐temporal exposure to each offshore wind area.
Surf Scoters and Red‐throated Loons were exposed to offshore wind areas almost exclusively during migration because these species were distributed among coastal and inshore waters during winter months. In contrast, Northern Gannets ranged over a much larger area, reaching farther offshore and south in winter, thus exhibited the greatest exposure to extant offshore wind areas.
Results of this study provide better understanding of how diving birds use current and potential future offshore wind areas on the Atlantic OCS, and can inform permitting, risk assessment and pre‐ and post‐construction impact assessments of offshore energy infrastructure.
Annotated bibliography of scientific research on greater sage-grouse published from 2015 to 2019
Released September 30, 2020 17:33 EST
2020, Open-File Report 2020-1103
Sarah K. Carter, Robert S. Arkle, Heidi L. Bencin, Benjamin R. Harms, Daniel J. Manier, Aaron N. Johnston, Susan L. Phillips, Steven E. Hanser, Zachary H. Bowen
The greater sage-grouse (Centrocercus urophasianus; hereafter GRSG) has been a focus of scientific investigation and management action for the past two decades. The 2015 U.S. Fish and Wildlife Service listing determination of “not warranted” was in part due to a large-scale collaborative effort to develop strategies to conserve GRSG populations and their habitat and to reduce threats to both. New scientific information augments existing knowledge and can help inform updates or modifications to existing plans for managing GRSG and sagebrush ecosystems. However, the sheer number of scientific publications can be a challenge for managers tasked with evaluating and determining the need for potential updates to existing planning documents. To assist in this process, the U.S. Geological Survey (USGS) has reviewed and summarized the scientific literature published since January 1, 2015. The first GRSG literature summary was published early in 2018. Here we provide an update to that document by adding summaries of articles published between January 6, 2018 and October 2, 2019.
To identify articles and reports published about GRSG, we first conducted a structured search of three reference databases (Web of Science, Scopus, and Google Scholar) using the search term “greater sage-grouse.” We refined the initial list of products by (1) removing duplicates, (2) excluding products that were not published as research or scientific review articles in peer-reviewed journals or as formal technical reports, and (3) retaining only those products for which GRSG or their habitat was a research focus.
We summarized the contents of each product by using a consistent structure (background, objectives, methods, location, findings, and implications) and assessed the content of each product relevant to a list of 31 management topics. These topics include GRSG biology and habitat characteristics along with potential management actions, land uses, and environmental factors related to GRSG management and conservation. We also noted which articles/reports created new geospatial data.
Our original search, conducted on January 7, 2018, and the application of our criteria, resulted in the inclusion of 169 published products (2 of these products were published corrections to journal articles). This update adds summaries of 69 products published between then and October 2, 2019. The management topics most commonly addressed were GRSG behavior or demographics and GRSG habitat selection or habitat characteristics at broad or site scales. Few products addressed captive breeding, recreation, wild horses and burros, and range management structures (including fences). The management topics with the largest increase in representation between the 2018 GRSG literature summary and this update were GRSG survival and GRSG population estimates or targets, which were each addressed in 16 percent of products in the original literature summary document, but were addressed in 30 and 33 percent, respectively, of newly summarized products. Topics with the largest declines in representation were conifer expansion, - 17 to 10 percent, and new geospatial data, -31 to 21 percent. We include in this annotated bibliography the full citation, Digital Object Identifier (DOI), product summary, and management topics addressed by each product. The online version of this bibliography (https://apps.usgs.gov/gsgbib/index.php) is searchable by topic and location and includes links to journal landing pages for each original publication.
A substantial body of literature has been compiled on research explicitly related to the conservation, management, monitoring, and assessment of GRSG. These studies may inform planning and management actions that seek to balance conservation, economic, and social objectives and manage diverse resource uses and values across the western United States.
The review process for this product included requesting input on each summary from one or more authors of the original peer-reviewed article or report and a formal review of the entire document by three independent reviewers for the original document and by two independent reviewers for the updated document and, subsequently, the USGS Bureau Approving Official. This process is consistent with USGS Fundamental Science Practices.
Integrating climate change considerations into natural resource planning—An implementation guide
Released September 30, 2020 17:00 EST
2020, Techniques and Methods 6-C2
Jessi Kershner, Andrea Woodward, Alicia Torregrosa
Climate change vulnerability assessments and associated adaptation strategies and actions connect existing climate science with possible effects on natural resources and highlight potential responses. However, these assessments, which are commonly generated for large regional areas, suggest management options in general terms without guidance for choosing among strategies and actions under specific circumstances. Meanwhile, land and resource management plans1 often address smaller geographies, and management actions must address specific rather than general situations. Thus, there is a need for tools that enable managers to bridge the gap by downscaling assessments, plans, and data generated at regional scales to identify adaptation actions and strategies appropriate for smaller management units and project-level planning.
To address this need, we have developed a tool–the Climate Adaptation Integration Tool (CAIT)–that helps resource managers use climate science and assessments, along with local knowledge, to identify those adaptation strategies and actions most appropriate for a given site or situation. Specifically, we provide:
- Guidance for acquiring and using downscaled climate change projections;
- Procedures for using these data to answer Critical Questions to make site-specific determinations of the appropriate management approach (specifically, resistance, resilience, transition, realignment, or no action);
- Lists of potential adaptation strategies and actions appropriate to the chosen management approach; and
- Supplemental information regarding adaptation strategies and actions to help managers choose among them.
The CAIT is meant to help managers integrate climate change science and assessments into management decisions. The CAIT also serves as a way for managers to document how they have incorporated climate change information into their decision-making and why certain actions were selected over others. A particular strength of the CAIT is that it leads to potential solutions (that is, adaptation strategies and actions) without inflexibly prescribing actions. This flexibility enables managers to incorporate other factors and constraints to create workable management plans and projects that strengthen their ability to achieve long-term conservation goals.
Trends in concentration, loads, and sources of trace metals and nutrients in the Spokane River Watershed, northern Idaho, water years 1990–2018
Released September 30, 2020 12:48 EST
2020, Scientific Investigations Report 2020-5096
Lauren M. Zinsser
A long history of mining and widespread metals contamination in the Coeur d’Alene River watershed and downstream into the Spokane River has led to the area’s designation as a Superfund site and to extensive, ongoing (as of 2020) remedial actions. Long-term water-quality and streamflow data, collected by the U.S. Geological Survey for up to 29 years at 20 sampling sites in the Coeur d’Alene, Spokane and St. Joe River watersheds, were analyzed to evaluate the impact of remedial actions on metals in surface water. Analyses focused on total and dissolved cadmium, zinc and lead. Trends in total phosphorus, total nitrogen and dissolved orthophosphate were also evaluated; although these nutrients are not constituents of concern for the Superfund site, they are important to the health of Coeur d’Alene Lake.
Dissolved cadmium, zinc and lead concentrations were compared to ambient water-quality criteria at 20 sample sites. For the 12 sites with the most extensive data records, Weighted Regressions on Time, Discharge and Season (WRTDS) models were developed to estimate flow-normalized annual mean concentrations and flow-normalized annual total loads; these results were used to evaluate trends because flow-normalization dampens the impact of interannual streamflow variability on concentrations and loads. WRTDS models with Kalman filtering (WRTDS_K) were developed to estimate annual mean concentrations and annual total loads; these results were used to evaluate spatial patterns in constituent sources. Models were developed for total and dissolved cadmium, lead, and zinc; total phosphorus and nitrogen; and dissolved orthophosphate, although not all constituents were modeled for all sites due to limited sample sizes. Bootstrapped confidence intervals were constructed to determine the statistical likelihood of trends and the slope of trends in flow-normalized concentrations and loads during the period of record (13–29 years, depending on the site), water years 1999–2009, and water years 2009–18.
Pesticide mixtures show potential toxicity to aquatic life in U.S. streams, water years 2013-2017
Released September 30, 2020 12:47 EST
2020, Science of the Total Environment
S. Alex. Covert, Megan E. Shoda, Sarah M. Stackpoole, Wesley W. Stone
During water years (WY) 2013–2017, the U.S. Geological Survey, National Water-Quality Assessment (NAWQA) Project, sampled the National Water Quality Network – Rivers and Streams (NWQN) year-round and reported on 221 pesticides at 72 sites across the United States in agricultural, developed, and mixed land use watersheds. The Pesticide Toxicity Index (PTI) was used to estimate the potential chronic and acute toxicity to three taxonomic groups – fish, cladocerans, and benthic invertebrates. For invertebrates (either cladocerans, benthic invertebrates, or both), the maximum PTI score exceeded the predicted acute toxicity screening level at 18 of the 72 sites (25%) at some point during WY 2013–2017. The predicted toxicity of a single pesticide compound was found to overwhelm the toxicity of other pesticides in the mixtures after concentrations were toxicity weighted. For this study, about 71%, 72%, and 92% of the Fish-, Cladoceran-, and Benthic Invertebrate-PTI scores, respectively, had one pesticide compound primarily contributing to sample potential toxicity (>50%).
There were 17 (13 insecticides, 2 herbicides, 1 fungicide, and 1 synergist) of the 221 pesticide compounds analyzed that were the primary drivers of potential toxicity in each water sample in which the PTI and TUmax (toxic unit score for the pesticide that makes the single largest contribution to the PTI) scores were above predicted chronic (>0.1) or acute (>1) toxicity levels for one of the three taxa. For cladocerans and benthic invertebrates, the drivers of predicted chronic (>0.1) and acute (>1) PTIs were mostly insecticides. For cladocerans, the pesticide compounds driving the PTI scores were bifenthrin, carbaryl, chlorpyrifos, diazinon, dichlorvos, dicrotophos, diflubenzuron, flubendiamide, and tebupirimfos. For benthic invertebrates, atrazine (an herbicide), as well as the insecticides – bifenthrin, carbaryl, carbofuran, chlorpyrifos, diazinon, dichlorvos, fipronil, imidacloprid, and methamidophos – were the drivers of predicted toxicity. For fish, there were three pesticide types that contributed the most to predicted chronic (>0.1) PTIs – acetochlor, an herbicide; carbendazim, a fungicide degradate; and piperonylbutoxide, a synergist.
Introduction to Special Issue: Gas Hydrates in Green Canyon Block 955, deep-water Gulf of Mexico: Part I
Released September 30, 2020 11:08 EST
2020, AAPG Bulletin (104) 1843-1846
Ray Boswell, Timothy Collett, Ann E. Cook, Peter B. Flemings
No abstract available.
Pressure coring operations during The University of Texas-Gulf of Mexico 2-1 (UT-GOM2-1) Hydrate Pressure Coring Expedition in Green Canyon Block 955, northern Gulf of Mexico
Released September 30, 2020 10:53 EST
2020, AAPG Bulletin (104) 1877-1901
Carla Thomas, Stephen C. Phillips, Peter B. Flemings, Manasij Santra, Helen Hammon, Timothy Collett, Ann Cook, Tom Pettigrew, Mike Mimitz, Melanie Holland, Peter Schultheiss
In May 2017, The University of Texas Hydrate Pressure Coring Expedition Gulf of Mexico 2-1 (UT-GOM2-1) drilled two adjacent holes in Green Canyon Block 955 in the deep-water Gulf of Mexico as part of The University of Texas at Austin and US Department of Energy Deepwater Methane Hydrate Characterization and Scientific Assessment. Expedition operations included testing two configurations of a rotary pressure-coring tool in a gas hydrate–bearing formation. In the first hole, an extended core barrel (cutting shoe) configuration of the Pressure Coring Tool with Ball Valve (PCTB-CS) was deployed, and in the second hole, the PCTB face bit configuration (PCTB-FB) was deployed. The PCTB-CS successfully recovered and maintained pressure for only one core out of eight deployments. A series of incremental modifications were made during and after the PCTB-CS deployment period that impacted the operations of the subsequent PCTB-FB deployments. Thus, in the second hole, the PCTB-FB successfully recovered and maintained pressure within the hydrate stability zone for 11 cores out of 13 deployments. The PCTB cored gas hydrate–bearing sandy silt interbedded with non–hydrate-bearing clayey silt within the main reservoir. The PCTB also recovered long intervals of unbroken, high-quality core with preserved sedimentary structures. We recovered one pressure core 130 m (437 ft) above the main hydrate reservoir in the silty clay. Pressure coring is the only available technology for recovering intact cores from sediment that is normally disturbed by gas expansion, dissolution, or dissociation; this allows a wide range of scientific measurements to be obtained with minimal disturbance to the core sediment fabric. Analysis of pressure cores has the potential to illuminate the in situ properties, gas saturation, and gas composition of a wide range of reservoirs including unconventional shale systems.
The Everglades Depth Estimation Network (EDEN) surface-water interpolation model, version 3
Released September 29, 2020 12:47 EST
2020, Scientific Investigations Report 2020-5083
Saira Haider, Eric Swain, James Beerens, Matthew Petkewich, Bryan McCloskey, Heather Henkel
The Everglades Depth Estimation Network (EDEN) is an integrated network of water-level gages, interpolation models that estimate daily water-level data at ungaged locations, and applications that generate derived hydrologic data across the freshwater part of the Greater Everglades landscape. Version 3 (V3) of the EDEN interpolation surface-water model is the most recent update, replacing the version 2 (V2) model released in 2011.
The primary revision for the V3 model is the switch to the R programming language to create a more efficient and portable EDEN code relative to V2, without reliance on proprietary software. Using R, the interpolation script runs over 10 times faster and is more easily updated, for example, to accommodate changes in the gage network or to incorporate R software updates. Additional revisions made for the V3 model include updates to the interpolation model, the gage network, and groundwater-level estimations. The EDEN model domain in the Greater Everglades and Big Cypress National Preserve is divided into subdomains that are based on hydrologic boundaries. In the V3 model, the number of subdomains was increased from five to eight, which allows hydrologic boundaries, such as levees and canals, to be better represented in the interpolation scheme. Five pseudogages were added to constrain the water-level surface at subdomain boundaries. Changes made to the water-level gage network between the implementation of the V2 and V3 models are incorporated, and groundwater-level estimations are added, which are important information for hydrologic and ecological studies.
Summary model performance statistics indicate similar accuracy in water-level surfaces generated by the V3 and V2 models, with a root mean square error of 4.78 centimeters for both interpolation models against independent water-level measurements. Providing stability and continuity for the EDEN user community, the V3 model closely replicates the V2 model, with a root mean square difference of 3.87 centimeters for interpolated surfaces from April 1, 2014, to March 31, 2018. The additional groundwater levels provide a realistic estimate of the saturated groundwater surface continuous with the surface-water surface for Water Conservation Areas 2A and 2B from 2000 to 2011. This continuous surface is a more accurate estimation of the spatial distribution of water in the hydrologic system than before, providing needed information for ecological studies in areas where depth to water table affects habitats. Development of the EDEN V3 model advances the tools available to scientists and resource managers for guiding large-scale field operations, describing hydrologic changes, and supporting biological and ecological assessments.
Shifting food web structure during dam removal—Disturbance and recovery during a major restoration action
Released September 29, 2020 12:46 EST
2020, PLoS ONE (15)
Sarah A. Morley, Melissa M Foley, Jeffrey J. Duda, Mathew M Beirne, Rebecca L Paradis, Rachelle Carina Johnson, Michael L. McHenry, Mel Elofson, Earnest M Sampson, Randall E McCoy, Justin Stapleton, George R. Pess
We measured food availability and diet composition of juvenile salmonids over multiple years and seasons before and during the world’s largest dam removal on the Elwha River, Washington State. We conducted these measurements over three sediment-impacted sections (the estuary and two sections of the river downstream of each dam) and compared these to data collected from mainstem tributaries not directly affected by the massive amount of sediment released from the reservoirs. We found that sediment impacts from dam removal significantly reduced invertebrate prey availability, but juvenile salmon adjusted their foraging so that the amount of energy in diets was similar before and during dam removal. This general pattern was seen in both river and estuary habitats, although the mechanisms driving the change and the response differed between habitats. In the estuary, the dietary shifts were related to changes in invertebrate assemblages following a hydrological transition from brackish to freshwater caused by sediment deposition at the river’s mouth. The loss of brackish invertebrate species caused fish to increase piscivory and rely on new prey sources such as plankton. In the river, energy provided to fish by Ephemeroptera, Plecoptera, and Trichoptera taxa before dam removal was replaced first by terrestrial invertebrates, and then by sediment-tolerant taxa such as Chironomidae. The results of our study are consistent with many others that have shown sharp declines in invertebrate density during dam removal. Our study further shows how those changes can move through the food web and affect fish diet composition, selectivity, and energy availability. As we move further along the dam removal response trajectory, we hypothesize that food web complexity will continue to increase as annual sediment load now approaches natural background levels, anadromous fish have recolonized the majority of the watershed between and above the former dams, and revegetation and microhabitats continue to develop in the estuary.
The distribution of woody species in relation to climate and fire in Yosemite National Park, California, USA
Released September 29, 2020 10:24 EST
2020, Fire Ecology (16)
Jan W. van Wagtendonk, Peggy E Moore, Julie L. Yee, James A. Lutz
The effects of climate on plant species ranges are well appreciated, but the effects of other processes, such as fire, on plant species distribution are less well understood. We used a dataset of 561 plots 0.1 ha in size located throughout Yosemite National Park, in the Sierra Nevada of California, USA, to determine the joint effects of fire and climate on woody plant species. We analyzed the effect of climate (annual actual evapotranspiration [AET], climatic water deficit [Deficit]) and fire characteristics (occurrence [BURN] for all plots, fire return interval departure [FRID] for unburned plots, and severity of the most severe fire [dNBR]) on the distribution of woody plant species.
Of 43 species that were present on at least two plots, 38 species occurred on five or more plots. Of those 38 species, models for the distribution of 13 species (34%) were significantly improved by including the variable for fire occurrence (BURN). Models for the distribution of 10 species (26%) were significantly improved by including FRID, and two species (5%) were improved by including dNBR. Species for which distribution models were improved by inclusion of fire variables included some of the most areally extensive woody plants. Species and ecological zones were aligned along an AET-Deficit gradient from cool and moist to hot and dry conditions.
In fire-frequent ecosystems, such as those in most of western North America, species distribution models were improved by including variables related to fire. Models for changing species distributions would also be improved by considering potential changes to the fire regime.
Potentiometric surfaces, 2011–12, and water-level differences between 1995 and 2011–12, in wells of the “200-foot,” “500-foot,” and “700-foot” sands of the Lake Charles area, southwestern Louisiana
Released September 28, 2020 10:47 EST
2020, Scientific Investigations Map 3460
Vincent E. White, Jason M. Griffith
Water levels were determined in 90 wells to prepare 2011–12 potentiometric surfaces focusing primarily on the “200-foot,” 500-foot,” and “700-foot” sands of the Lake Charles area, which are part of the Chicot aquifer system underlying Calcasieu and Cameron Parishes of southwestern Louisiana. These three aquifers provided 34 percent of the total water withdrawn and 93 percent of the groundwater withdrawn in Calcasieu and Cameron Parishes in 2012 (84.5 million gallons per day [Mgal/d]). This work was completed by the U.S. Geological Survey, in cooperation with the Louisiana Department of Transportation and Development, to assist in developing and evaluating groundwater-resource management strategies. The highest water levels determined in wells screened in the “200-foot,” “500-foot,” and “700-foot” sands were about 8 feet (ft) above the National Geodetic Vertical Datum of 1929 (NGVD 29), 2 ft below NGVD 29, and 14 ft below NGVD 29, respectively, and were located in northwestern Calcasieu Parish. The lowest water levels determined in wells screened in the “200-foot,” “500-foot,” and “700-foot” sands were approximately 50, 80, and 70 ft below NGVD 29, respectively, and were located in the southern Lake Charles metropolitan area, to the west of Prien Lake, and between the cities of Lake Charles and Sulphur, respectively. The primary groundwater flow direction in these three aquifers was radially towards pumping centers overlying the water-level lows. Comparisons of water-level differences in 42 wells measured in 1995 and 2011–12 indicated that the maximum increases in water levels for wells screened in the “200-foot,” “500-foot,” and “700-foot” sands were approximately 7, 31, and 19 ft, respectively. Water-level increases coincided with a decline in total groundwater withdrawals during the period (about 25 Mgal/d from 1995 to 2012) from these sands. More specifically, withdrawals from the “500-foot” sand affected water levels in wells screened in the “200-foot” and “700-foot” sands because the three are hydraulically connected and withdrawals from the “500-foot” sand were greater by volume than withdrawals from the “200-foot” and “700-foot” sands.
The collection and analysis of Bay of Fundy sediment under contract between the association of US delegates to the Gulf of Maine Council on the marine environment and eastern Charlotte waterways for contaminant monitoring and analysis
Released September 28, 2020 10:13 EST
James S Latimer, David Page, Adria Elskus, Lawrence A LeBlanc, Gareth Harding, Peter G Wells
This report presents data obtained through the EcoSystem Indicator Partnership (ESIP) which was established in 2006 to improve understanding and to inform researchers, managers, and citizens about the status and trends of ecosystem health in the Gulf of Maine (http://www.gulfofmaine.org/2/esip-homepage/). In its efforts to compile information on contaminant indicators in the Gulf of Maine, ESIP identified gaps in monitoring information and worked in partnership with the Gulf of Maine Council and other organizations to fill these gaps. The monitoring and data gaps identified by ESIP indicated that data on contaminants in intertidal/subtidal sediments were lacking for the Bay of Fundy. To address this data gap, the Association of US Delegates to the Gulf of Maine Council on the Marine Environment contracted Eastern Charlotte Waterways Inc., an independent non-governmental organization, to conduct a contaminant monitoring and analysis project funded by Environment and Climate Change Canada . This report summarizes the data produced from this sediment analysis project.
Spectral wave-driven bedload transport across a coral reef flat/lagoon complex
Released September 28, 2020 07:57 EST
2020, Frontiers in Marine Science
Kurt J. Rosenberger, Curt D. Storlazzi, Olivia Cheriton, Andrew Pomeroy, Jeff E. Hansen, Ryan Lowe, Mark Buckley
Why let the dogs out? Exploring variables associated with dog confinement and general characteristics of the free-ranging owned-dog population in a peri-urban area
Coral reefs are an important source of sediment for reef-lined coasts by helping to maintain beaches while also providing protection in the form of wave energy dissipation. Understanding the mechanisms by which sediment is delivered to the coast as well as better constraining the total volumes generated are critical for projecting future coastal change. A month-long hydrodynamics and sediment transport study on a fringing reef/lagoon complex in Western Australia indicates that lower frequency constituents of wave energy are important to the total bedload transport of sediment across the reef flat and lagoon to the shoreline. The reef flat and the lagoon are characterized by distinctly different transport regimes, resulting in an offset in the timing of bedform migration between the two. Short-term storage of sediment is noted on the reef flat, which is subsequently washed out into the lagoon when offshore wave heights increase and strong currents due to wave breaking at the reef crest develop. This sudden influx of sediment is a significant control on bedform migration rates in the lagoon. Infragravity wave energy on the reef flat and lagoon make an important contribution to the migration of bedforms and resultant bedload transport. Given the complexity of the hydrodynamics of fringing reefs, the transfer of energy to lower frequency bands, as well as accurate estimates of sources and sinks of sediment, must but considered in order to correctly model the transport of sediment from the reef to the coast.
Released September 27, 2020 08:04 EST
2020, Journal of Applied Animal Welfare Science
Francisca Astorga, Daniela Alejandra Poo-Muñoz, John F. Organ, Gonzalo Medina-Vogel
Modeling soil porewater salinity in mangrove forests (Everglades, Florida, USA) impacted by hydrological restoration and a warming climate
Free-ranging dogs (FRDs), are a problem in several countries, with impacts on humans, domestic animals, and wildlife, although increasing evidence suggests that most FRDs are owned. Therefore, understanding dog ownership on a fine scale is critical. The main objectives of this study were to explore dog management in rural localities from central Chile focusing on modeling owner-related variables associated with dog confinement and characterize confined and FRDs populations. Interviews (170) were carried out in Paine municipality, reporting a human:dog ratio of 1.5:1, and dogs in most households (85.9%, 146/170). Thirty-seven percent (54/146) of those households did not confine their dog(s) to some degree, and 41% (196/472) of surveyed dogs were FRD. Based on multivariable logistic regression models, non-confinement was decreased by (i) negative opinion of owners toward roaming behavior of their dogs, (ii) negative opinion toward FRDs, among others. Dog confinement increased along with owners' concerns about the impacts of their dogs on others. Owned-FRDs tended to have poorer general care than confined dogs. Our findings represent a contribution to the understanding of the human dimensions behind FRDs and provide critical quantitative elements to consider when planning effective control strategies.
Released September 26, 2020 09:49 EST
2020, Ecological Modelling (436)
Xiaochen Zhao, Victor H. Rivera-Monroy, Hongqing Wang, Zuo Xue, Cheng-Feng Tsai, C. S. Willson, E. Castañeda-Moya, Robert R. Twilley
Hydrology is a critical driver controlling mangrove wetlands structural and functional attributes at different spatial and temporal scales. Yet, human activities have negatively affected hydrology, causing mangrove diebacks and coverage loss worldwide. In fact, the assessment of mangrove water budgets, impacted by natural and human disturbances, is limited due to a lack of long-term data and information that hinders our understanding of how changes in hydroperiod and salinity control mangrove productivity and spatial distribution. In this study, we implemented a mass balance-based hydrological model (RHYMAN) that explicitly considers groundwater discharge in the Shark River estuary (SRE, southwestern Everglades) located in a karstic geomorphic setting and influenced by regional hydrological restoration. We used long-term hydroperiod and porewater salinity (PWS) datasets obtained from 2004 to 2016 for model calibration and validation and to determine spatiotemporal variability in water levels and PWS at three riverine mangrove sites (downstream, SRS-6; midstream, SRS-5; upstream, SRS-4) along SRE. Model results agree with a distinct PWS pattern along the estuarine salinity gradient where the highest PWS occurs at SRS-6 (mean: 25, range: 22–30 ppt), followed by SRS-5 (17, 14–25 ppt) and SRS-4 (5, 3–13 ppt). A commensurate increase in PWS over a thirteen-year period indicates a long-term reduction in freshwater inflow coupled with sea-level rise (SLR). Increasing freshwater scenario simulation results show a significant reduction (17–27%) in PWS along the estuary in contrast with a high SLR scenario when salinity increases up to 1.1 to 2.5 times that of control values. Model results show that freshwater inflow and SLR are key drivers controlling mangrove wetlands PWS in this karstic coastal region. Given its relatively simple structure, this mass balance-based hydrological model could be used in other environmental settings to evaluate potential habitat and regime shifts due to changes in hydrology and PWS under regional hydrological restoration management.
From lava to water: A new era at Kīlauea
Released September 25, 2020 12:34 EST
2020, Eos, Earth and Space Science News
Patricia Nadeau, Angela K. Diefenbach, Shaul Hurwitz, Donald A, Swanson
No abstract available.
Integrating physical and economic data into experimental water accounts for the United States: Lessons and opportunities
Released September 25, 2020 10:06 EST
2020, Ecosystem Services (45)
Kenneth J. Bagstad, Zachary H. Ancona, Julie L. Hass, Pierre D. Glynn, Scott Wentland, Michael Vardon, John P. Fay
heir value in the U.S., and (2) a roadmap for the completion of future accounts for water, a critical ecosystem service. Our work also aids in the interpretation of ecosystem accounts in the context of long-term water resources trends.
Predicting bird guilds using vegetation composition and structure on a wild and scenic river in Arizona
Released September 25, 2020 09:03 EST
Erin S. Cubley, Heather L. Bateman, Sidney B. Riddle, Christopher Holmquist-Johnson, David M. Merritt
Harmonizing the Landsat ground reference with the Sentinel-2 Global Reference Image using space-based bundle adjustment
Riparian areas are among the most ecologically diverse terrestrial ecosystems but make up <2% of landscape area in southwestern USA. Many species of resident and neotropical migratory birds utilize riparian habitats for breeding, foraging, and nesting. We quantified vegetation composition and structure to predict bird guilds on Wild and Scenic portions of the Verde River, Arizona. We grouped plant species into guilds based on similar functional traits to describe composition. We surveyed birds during the breeding and migrating season to determine abundance and categorized species into guilds using preferences of breeding habitat, foraging substrate, and nest placement. Riparian obligate and facultative breeding guilds were most common. Both vegetation composition and structure were useful predictors of birds. Vegetation structure was most complex in gallery riparian forest. Abundance of riparian-obligate birds in the breeding guild were positively associated with vegetation structure of dense, multi-canopy canopy and tall trees. Abundance of most bird guilds were positively associated with composition of tall trees (Populus fremontii, Salix gooddingii) and drought tolerant shrubs (Prosopis velutina, Celtis reticulata). Our findings show complex riparian habitat important to wildlife is created by both composition and structure of near-stream vegetation that is tied to hydrology and sensitive to flow change.
Released September 24, 2020 12:14 EST
2020, MDPI Remote Sensing (12)
Rajagopalan Rengarajan, James C. Storey, Michael Choate
There is an ever-increasing need to use accurate and consistent geometric ground reference in the processing of remotely sensed data products as it reduces the burden on the end-users to account for the differences between the data products from different missions. In this regard, United States Geological Survey (USGS) initiated an effort to harmonize the Landsat ground reference with the Sentinel-2 Global Reference Image (GRI) to improve the co-registration between the data products of the two global medium-resolution missions. In this paper, we have discussed the process, results, and the improvements expected from this harmonization of two ground references using space-triangulation based bundle adjustment techniques. The ground coordinates of the Landsat reference library, consisting of 5 million Ground Control Points (GCPs) were adjusted in a series of four simultaneous bundle block adjustments using thousands of Landsat-8 (L8) scenes anchored with more than 300,000 control points extracted from the GRI dataset. The net adjustments to each of the four blocks, namely, Australia, Americas, Eurasia, and Islands, varied anywhere from 1 m to 13 m, depending on the accuracy of the GCPs in these blocks. The use of the GRI dataset in our bundle adjustment not only improved the absolute accuracy of the Landsat ground reference but
will also improve the co-registration between Sentinel-2 and Landsat terrain corrected products, as the European Space Agency plans to process the Sentinel-2 products using the GRI dataset. Independent validation of the Landsat products processed using harmonized GCPs with the GRI dataset indicated a global mis-registration error of less than 8 m Circular Error Probable at 90 % (CE90), an improvement from 25 meters prior to harmonization. The improvements to the Landsat products using the harmonized GCPs will be available to the public as part of Landsat Collection-2 processing by the end of 2020.
Field evaluation of the Sequoia Scientific LISST-ABS acoustic backscatter sediment sensor
Released September 24, 2020 11:47 EST
2020, Open-File Report 2020-1096
Adam E. Manaster, Timothy D. Straub, Molly S. Wood, Joseph M. Bell, Daniel E. Dombroski, Christopher A. Curran
Sequoia Scientific’s LISST-ABS is a submersible acoustic instrument that measures the acoustic backscatter sensor (ABS) concentration at a point within a river, stream, or creek. Compared to traditional physical methods for measuring suspended-sediment concentration (SSC), sediment surrogates like the LISST-ABS offer continuous data that can be calibrated with physical SSC samples. Data were collected at 10 U.S. Geological Survey streamflow-gaging stations between January 10, 2016, and February 21, 2018, across the contiguous United States to test the accuracy and effectiveness of using the LISST-ABS as a surrogate for measuring the concentration of suspended sediment in a dynamic fluvial system. Correlation coefficients (Pearson’s r values) relating the ABS concentration and SSC from physical samples ranged from r = 0.718 to r = 0.956 at the 10 stations with the mean percentage of fines (percentage of the sediment less than 62.5 microns in diameter) ranging from 65 to 100 percent (with minimum and maximum values of 18 and 100 percent, respectively). The LISST-ABS instruments used in this field evaluation were factory-calibrated to accurately determine SSC for grains in the diameter range of 75–90 microns. Note that the sensor responds to grains of arbitrary sizes, but the accuracy varies at sizes other than this calibration size. For operational use, regression models could be determined for the ABS concentrations and SSC values or the instrument could be recalibrated to sediments for each fluvial environment. However, such calibrations were beyond the scope of this report.
The effects of management practices on grassland birds—Nelson’s Sparrow (Ammospiza nelsoni nelsoni)
Released September 24, 2020 10:09 EST
2020, Professional Paper 1842-KK
Jill A. Shaffer, Lawrence D. Igl, Douglas H. Johnson, Marriah L. Sondreal, Christopher M. Goldade, Paul A. Rabie, Betty R. Euliss
The key to Nelson’s Sparrow (Ammospiza nelsoni nelsoni) management is providing dense grasses or emergent vegetation near damp areas or freshwater wetlands. Nelson’s Sparrows have been reported to use habitats with 20–122 centimeters (cm) average vegetation height, 41 cm visual obstruction reading, 40–58 percent grass cover, 24 percent forb cover, 5 percent shrub cover, 13 percent bare ground, and 2–7 cm litter depth.
Migratory status determines resource selection by American Woodcock at an important fall stopover, Cape May, New Jersey
Released September 24, 2020 09:58 EST
2020, The Condor
Brian L. Allen, Daniel McAuley, Erik J. Blomberg
Migration is a period of high activity and exposure during which risks and energetic demand on individuals may be greater than during nonmigratory periods. Stopover locations can help mitigate these threats by providing supplemental energy en route to the animal’s end destination. Effective conservation of migratory species therefore requires an understanding of use of space that provides resources to migratory animals at stopover sites. We conducted a radio-telemetry study of a short-distance migrant, the American Woodcock (Scolopax minor), at an important stopover site, the Cape May Peninsula, New Jersey. Our objectives were to describe land-cover types used by American Woodcock and evaluate home range habitat selection for individuals that stopover during fall migration and those that choose to overwinter. We radio-marked 271 individuals and collected 1,949 locations from these birds (0–21 points individual–1) over 4 yr (2010 to 2013) to inform resource selection functions of land-cover types and other landscape characteristics by this species. We evaluated these relationships at multiple spatial extents for (1) birds known to have ultimately left the peninsula (presumed migrants), and (2) birds known to have remained on the peninsula into the winter (presumed winter residents). We found that migrants selected deciduous wetland forest, agriculture, mixed shrub, coniferous wetland forest, and coniferous shrub, while wintering residents selected deciduous wetland forest, coniferous shrub, and deciduous shrub. We used these results to develop predictive models of potential habitat: 7.80% of the peninsula was predicted to be potential stopover habitat for American Woodcock (95% classification accuracy) and 4.96% of the peninsula was predicted to be potential wintering habitat (85% classification accuracy). Our study is the first to report habitat relationships for migratory American Woodcock in the coastal U.S. and provides important spatial tools for local and regional managers to support migratory and winter resident woodcock populations into the future.
Why did Great Basin Eocene magmatism generate Carlin-type gold deposits when extensive Jurassic to Middle Miocene magmatism did not? Lessons from the Cortez Region, Northern Nevada, USA
Released September 24, 2020 09:03 EST
2020, Conference Paper, Vision for discovery: Geological Society of Nevada symposium proceedings
Christopher D. Henry, David A. John, Matt T. Heizler, Robert W. Leonardson, Joseph P. Colgan, Kathryn E. Watts, Michael W. Ressel, Brian L. Cousens
No abstract available.
Geologic framework and hydrostratigraphy of the Edwards and Trinity aquifers within northern Medina County, Texas
Released September 24, 2020 08:37 EST
2020, Scientific Investigations Map 3461
Allan K. Clark, Robert E. Morris, Diana E. Pedraza
The karstic Edwards and Trinity aquifers are classified as major sources of water in south-central Texas by the Texas Water Development Board. During 2018–20 the U.S. Geological Survey, in cooperation with the Edwards Aquifer Authority, mapped and described the geologic framework and hydrostratigraphy of the rocks composing the Edwards and Trinity aquifers in northern Medina County from field observations of the surficial expressions of the rocks. The thicknesses of the mapped lithostratigraphic members and hydrostratigraphic units were also estimated from field observations.
The Cretaceous-age rocks (listed in ascending order) in the study area are part of the Trinity Group (lower and upper members of the Glen Rose Limestone), Edwards Group (Kainer Formation [and its stratigraphic equivalent, the Fort Terrett Formation] and Person Formation), Devils River Limestone, Washita Group (Georgetown Formation, Del Rio Clay, and Buda Limestone), Eagle Ford Group, Austin Group, Taylor Group, and Late Cretaceous igneous intrusive rocks. The groups and formations are composed primarily of relatively thick layers of clays, shales, and limestone. The igneous rocks are coarse-grained ultramafic in composition.
The principal structural feature in northern Medina County is the Balcones fault zone, which is the result of late Oligocene and early Miocene extensional faulting and fracturing resulting from the eastern Edwards Plateau uplift. In the Balcones fault zone, most of the faults in the study area are high-angle to vertical, en echelon, normal faults that are predominately downthrown to the southeast.
Hydrostratigraphically, the rocks exposed in the study area (listed in descending order from land surface as they appear in a stratigraphic column) are igneous, the upper confining unit to the Edwards aquifer, the Edwards aquifer, the upper zone of the Trinity aquifer, and the upper part of the middle zone of the Trinity aquifer. The karstic carbonate Edwards and Trinity aquifers developed as a result of their original depositional history, primary and secondary porosity, diagenesis, fracturing, and faulting. These factors have resulted in development of modified porosity, permeability, and transmissivity within and between the aquifers.
USGS enterprise tools for efficient and effective management of science data
Released September 23, 2020 11:25 EST
2020, Fact Sheet 2020-3041
Vivian B. Hutchison, Amanda Liford, Ricardo McClees-Funinan, Lisa Zolly, Drew Ignizio, Madison Langseth, Brandon Serna, Elizabeth Sellers, Leslie Hsu, Tamar Norkin, Marcia McNiff, Grace Donovan
The Science Data Management Branch (SDM) of the U.S. Geological Survey (USGS) provides data management expertise and leadership and develops guidance and tools to support the USGS in providing the nation with reliable scientific information on the basis of which to describe the Earth. The SDM suite of tools supports the USGS Data Management Lifecycle by facilitating quality assurance, description, curation, and publishing of the Bureau's scientific data. The SDM suite of tools includes the USGS Data Management Website, USGS Science Data Catalog, Digital Object Identifier Tool, ScienceBase, ScienceBase Data Release Tool, Metadata Wizard, and Online Metadata Editor.
The pathogenesis of a North American H5N2 clade 184.108.40.206 group A highly pathogenic avian influenza virus in surf scoters (Melanitta perspicillata)
Released September 23, 2020 09:14 EST
2020, BMC Veterinary Research (16)
Jasmine M. Luczo, Diann Prosser, Mary J. Pantin-Jackwood, Alicia Berlin, Erica Spackman
Aquatic waterfowl, particularly those in the order Anseriformes and Charadriiformes, are the ecological reservoir of avian influenza viruses (AIVs). Dabbling ducks play a recognized role in the maintenance and transmission of AIVs. Furthermore, the pathogenesis of highly pathogenic AIV (HPAIV) in dabbling ducks is well characterized. In contrast, the role of diving ducks in HPAIV maintenance and transmission remains unclear. In this study, the pathogenesis of a North American A/Goose/1/Guangdong/96-lineage clade 220.127.116.11 group A H5N2 HPAIV, A/Northern pintail/Washington/40964/2014, in diving sea ducks (surf scoters, Melanitta perspicillata) was characterized.
Intrachoanal inoculation of surf scoters with A/Northern pintail/Washington/40964/2014 (H5N2) HPAIV induced mild transient clinical disease whilst concomitantly shedding high virus titers for up to 10 days post-inoculation (dpi), particularly from the oropharyngeal route. Virus shedding, albeit at low levels, continued to be detected up to 14 dpi. Two aged ducks that succumbed to HPAIV infection had pathological evidence for co-infection with duck enteritis virus, which was confirmed by molecular approaches. Abundant HPAIV antigen was observed in visceral and central nervous system organs and was associated with histopathological lesions.
Collectively, surf scoters, are susceptible to HPAIV infection and excrete high titers of HPAIV from the respiratory and cloacal tracts whilst being asymptomatic. The susceptibility of diving sea ducks to H5 HPAIV highlights the need for additional research and surveillance to further understand the contribution of diving ducks to HPAIV ecology.
Simultaneous observations of geoelectric and geomagnetic ﬁelds produced by magnetospheric ULF waves
Released September 23, 2020 08:01 EST
2020, Geophysical Research Letters (47)
M. D. Hartinger, X. R. Shih, G. Lucas, Benjamin Scott Murphy, Anna Kelbert, J.B.H. Baker, E. Joshua Rigler, Paul A. Bedrosian
Total water level data from the January and March 2018 nor’easters for coastal areas of New England
Geomagnetic perturbations (BGEO) related to magnetospheric ultralow frequency (ULF) waves induce electric fields within the conductive Earth—geoelectric fields (EGEO)—that in turn drive geomagnetically induced currents. Though numerous past studies have examined ULF wave BGEO from a space weather perspective, few studies have linked ULF waves with EGEO. Using recently available magnetotelluric impedance and EGEO measurements in the contiguous United States, we explore the relationship between ULF waves and EGEO. We use satellite, ground‐based radar, BGEO, and EGEO measurements in a case study of a plasmaspheric virtual resonance (PVR), demonstrating that the PVR EGEO has significant spatial variation in contrast to a relatively uniform BGEO, consistent with spatially varying Earth conductivity. We further show ULF wave EGEO measurements during two moderate storms of ∼1 V/km. We use both results to highlight the need for more research characterizing ULF wave EGEO.
Released September 22, 2020 16:15 EST
2020, Scientific Investigations Report 2020-5048
Gardner C. Bent, Nicholas J. Taylor
During winter 2017–18 coastal areas of New England were impacted by the January 4, and March 2–4, 2018, nor’easters. The U.S. Geological Survey (USGS), under an interagency agreement with the Federal Emergency Management Agency (FEMA), collected total water level data (the combination of tide, storm surge, wave runup and setup, and freshwater input) using the North American Vertical Datum of 1988 (NAVD 88) from high-water marks and continuous water-level sensors, to better understand the areal extent, timing, and impact of coastal flooding from strong storms.
During the January 4, 2018, nor’easter the National Oceanic and Atmospheric Administration (NOAA) Boston, Massachusetts, tide gage recorded the highest total water level on record of 9.66 ft. During the March 2–4, 2018, nor’easter, the Boston tide gage recorded its third highest total water level on record of 9.16 ft.
After the January and March 2018 nor’easter storms, the USGS deployed field teams that identified and flagged high-water marks along the coastlines of eastern Massachusetts in January and from Portland, Maine, south to the Connecticut-New York State border in March. In preparation for the approach of the March 2018 nor’easter, the USGS deployed 35 temporary water-level sensors along the coastline of New England to collect total water level data during the storm. Total water level data were also collected at 28 tide gages and 14 coastal streamgages (affected tidally or by tidal backwater during coastal storms) in New England during both nor’easters.
Total water level elevations at 71 high-water marks collected after the January 2018 nor’easter in coastal areas of eastern Massachusetts ranged from 5.8 to 15.1 feet (ft), with an average elevation of 9.4 ft and a median elevation of 9.6 ft. Total water level elevations at 10 tide gages and 7 coastal streamgages from Portland to Cape Cod Bay ranged from 4.8 to 11.2 ft, with an average of 9.1 ft and a median of 9.6 ft. Following the March 2018 nor’easter, 111 high-water marks were collected along the New England coastline. Of the 111 high-water marks, 100 were along the eastern coastline of New England from Portland to Cape Cod and had elevations that ranged from 5.3 to 15.1 ft, with an average of 8.9 ft and a median of 8.6 ft. The remaining 11 high-water marks along the southern coastline of New England in Connecticut, Rhode Island, and Massachusetts had elevations that ranged from 3.1 to 7.5 ft, with an average of 4.3 ft and a median of 4.9 ft. Total water level elevations for 19 USGS temporary water-level sensors from Portland to Cape Cod Bay ranged from 6.2 to 10.4 ft, with an average of 8.4 ft and a median of 8.7 ft. Total water level elevations at 10 tide gages and 6 coastal streamgages from Portland to Cape Cod Bay ranged from 7.8 to 10.8 ft, with an average of 9.1 ft and a median of 9.2 ft.
There were 10 tide gages and 5 coastal streamgages with data from both nor’easters from Portland to Cape Cod Bay; for the January nor’easter, the average and median elevations were about 0.3 and 0.5 ft higher, respectively, than for the March nor’easter. At the 52 high-water mark locations with data for both nor’easters in Massachusetts, the average and median elevations were 0.1 and 0.4 ft higher, respectively, for the January nor’easter than for the March nor’easter.
At 10 tide gages along the coastline from Portland to Cape Cod Bay, the observed peak total water level elevations for the January nor’easter ranged from 1.6 to 3.7 ft higher than the concurrent predicted elevations, with an average of 2.8 ft and a median of 3.0 ft higher. For the March nor’easter, the observed peak total water level elevations ranged from 1.8 to 4.0 ft higher than the concurrent predicted elevations, with an average of 2.7 ft and a median of 3.0 ft higher. This is approximately the amount of storm surge that was experienced during the highest tides of the two nor’easters along the coastline from Portland to Cape Cod Bay.
The effects of management practices on grassland birds—Prairie Falcon (Falco mexicanus)
Released September 22, 2020 11:44 EST
2020, Professional Paper 1842-S
John P. DeLong, Karen Steenhof
Keys to Prairie Falcon (Falco mexicanus) management include maintaining cliffs with suitable recesses for use as nest sites (that is, the substrate that supports the nest or the specific location of the nest on the landscape), protecting nest sites from human disturbance by designating buffer zones, and maintaining open landscapes and habitats that support populations of ground squirrels (Urocitellus species) and small birds.
Observed and modeled mercury and dissolved organic carbon concentrations and loads at control structure S-12D, Florida Everglades, 2013–17
Released September 22, 2020 09:39 EST
2020, Open-File Report 2020-1092
Amanda C. Booth, Brett A. Poulin, David P. Krabbenhoft
Mercury (Hg) has been a contaminant of concern for several decades in South Florida, particularly in the Florida Everglades. The transport and bioavailability of Hg in aquatic systems is intimately linked to dissolved organic carbon (DOC). In aquatic systems, Hg can be converted to methylmercury (MeHg), which is the form of Hg that bioaccumulates in food webs. The bioaccumulation of MeHg poses significant health risks to wildlife and humans. Fish consumption advisories triggered by elevated Hg levels first appeared in the 1980s in South Florida. Multiple structures regulate freshwater distribution to Everglades National Park, including S-12D. This report summarizes seasonal and annual concentration and load data from late September 2013 to April 2017 for the total of (1) filter-passing total mercury (FTHg), (2) filter-passing methylmercury (FMeHg), (3) particulate total mercury (PTHg), (4) particulate methylmercury (PMeHg) and, (5) DOC discharged through control structure S-12D. The loads of Hg fractions and DOC at control structure S-12D were determined by pairing discharge data with constituent concentrations estimated by empirical models based on surrogate in situ water-quality measurements.
Calculated concentrations of DOC ranged from 12.8 milligrams per liter (mg/L) to 27.9 mg/L with a mean of 18.8 mg/L during the study period. Annual loads of DOC ranged from 3,950 tons in 2015 to 10,900 tons in 2016. DOC loads increased linearly with an increase in flow, and the highest monthly DOC load of 1,630 tons was observed in February 2016.
Calculated concentrations of FTHg ranged from 0.35 to 1.55 nanograms per liter (ng/L) with a mean of 0.85 ng/L during the study period. Calculated concentrations of FMeHg ranged from 0.06 ng/L to 0.24 ng/L with a mean of 0.14 ng/L during the study period. Generally, FTHg and FMeHg concentrations were lower during periods of decreased flow and higher during periods of increased flow. Calculated PTHg concentrations ranged from 0.09 ng/L to 4.19 ng/L with a mean of 0.58 ng/L during the study period. Calculated PMeHg concentrations ranged from below the limit of detection <0.01 ng/L to 0.29 ng/L with a mean of 0.03 ng/L during the study period.
Loads of Hg were often zero or lowest from November to May, owing to the lack of flow or low-flow conditions. FTHg and FMeHg loads increased linearly with an increase in flow and typically were highest from June to October. During periods of increasing flow or following changes in gate operations, PTHg and PMeHg constituted a greater percentage of the total Hg load. Annual loads of total Hg (filter-passing and particulate) ranged from 254 grams in 2015 to 658 grams in 2016. FTHg was the predominant contributor to the total Hg load. Information presented herein provides the first assessment of DOC and Hg loads to Everglades National Park through control structure S-12D using continuous in situ measurements of discharge and constituent surrogates and compares the surrogate model approach to loads calculated from monthly sampling. Analysis of calculated and observed loads demonstrates the significance of flow data on calculating constituent loads.
Occurrence and spatiotemporal dynamics of pharmaceuticals in a temperate-region wastewater effluent-dominated stream: Variable inputs and differential attenuation yield evolving complex exposure mixtures
Released September 22, 2020 07:00 EST
2020, Environmental Science & Technology (54) 12967-12978
Hui Zhi, Dana W. Kolpin, R.D. Klaper, Luke R. Iwanowicz, Shannon M. Meppelink, Gregory H. LeFevre
Effluent-dominated streams are becoming increasingly common in temperate regions and generate complex pharmaceutical mixture exposure conditions that may impact aquatic organisms via drug–drug interactions. Here, we quantified spatiotemporal pharmaceutical exposure concentrations and composition mixture dynamics during baseflow conditions at four sites in a temperate-region effluent-dominated stream (upstream, at, and progressively downstream from effluent discharge). Samples were analyzed monthly for 1 year for 109 pharmaceuticals/degradates using a comprehensive U.S. Geological Survey analytical method and biweekly for 2 years focused on 14 most common pharmaceuticals/degradates. We observed a strong chemical gradient with pharmaceuticals only sporadically detected upstream from the effluent. Seventy-four individual pharmaceuticals/degradates were detected, spanning 5 orders of magnitude from 0.28 to 13 500 ng/L, with 38 compounds detected in >50% of samples. “Biweekly” compounds represented 77 ± 8% of the overall pharmaceutical concentration. The antidiabetic drug metformin consistently had the highest concentration with limited in-stream attenuation. The antihistamine drug fexofenadine inputs were greater during warm- than cool-season conditions but also attenuated faster. Differential attenuation of individual pharmaceuticals (i.e., high = citalopram; low = metformin) contributed to complex mixture evolution along the stream reach. This research demonstrates that variable inputs over multiple years and differential in-stream attenuation of individual compounds generate evolving complex mixture exposure conditions for biota, with implications for interactive effects.