View of Lake Mead and Las Vegas, Nevada area from Sklyab

NASA Image and Video Library

1973-08-01

SL3-28-059 (July-September 1973) --- A vertical view of the Lake Mead and Las Vegas, Nevada area as photographed from Earth orbit by one of the six lenses of the Itek-furnished S190-A Multispectral Photographic Facility Experiment aboard the Skylab space station. Lake Mead is water of the Colorado River impounded by Hoover Dam. Most of the land in the picture is Nevada. However, a part of the northwest corner of Arizona can be seen. Federal agencies participating with NASA on the EREP project are the Departments of Agriculture, Commerce, Interior, the Environmental Protection Agency and the Corps of Engineers. All EREP photography is available to the public through the Department of Interior?s Earth Resources Observations Systems Data Center, Sioux Falls, South Dakota, 57198. Photo credit: NASA

Last glacial maximum and Holocene lake levels of Owens Lake, eastern California, USA

USGS Publications Warehouse

Bacon, S.N.; Burke, R.M.; Pezzopane, S.K.; Jayko, A.S.

2006-01-01

Stratigraphic investigations of fluvio-deltaic and lacustrine sediments exposed in stream cuts, quarry walls, and deep trenches east of the Sierra Nevada in Owens Valley near Lone Pine, California have enabled the reconstruction of pluvial Owens Lake level oscillations. Age control for these sediments is from 22 radiocarbon (14C) dates and the identification and stratigraphic correlation of a tephra, which when plotted as a function of age versus altitude, define numerous oscillations in the level of pluvial Owens Lake during the latest Pleistocene and early Holocene. We have constructed a lake-level altitude curve for the time interval ???27,000 cal yr BP to present that is based on the integration of this new stratigraphic analysis with published surface stratigraphic data and subsurface core data. Pluvial Owens Lake regressed from its latest Pleistocene highstands from ???27,000 to ???15,300 cal yr BP, as recorded by ???15 m of down cutting of the sill from the altitudes of ???1160 to 1145 m. By ???11,600 cal yr BP, the lake had dropped ???45 m from the 1145 m sill. This lowstand was followed by an early Holocene transgression that attained a highstand near 1135 m before dropping to 1120 m at 7860-7650 cal yr BP that had not been recognized in earlier studies. The lake then lowered another ???30 m to shallow and near desiccation levels between ???6850 and 4300 cal yr BP. Fluvial cut-and-fill relations north of Lone Pine and well-preserved shoreline features at ???1108 m indicate a minor lake-level rise after 4300 cal yr BP, followed by alkaline and shallow conditions during the latest Holocene. The new latest Quaternary lake-level record of pluvial Owens Lake offers insight to the hydrologic balance along the east side of the southern Sierra Nevada and will assist regional paleoclimatic models for the western Basin and Range. ?? 2005 Elsevier Ltd. All rights reserved.

Co-precipitation of dissolved organic matter by calcium carbonate in Pyramid Lake, Nevada

USGS Publications Warehouse

Leenheer, Jerry A.; Reddy, Michael M.

2008-01-01

Our previous research has demonstrated that dissolved organic matter (DOM) influences calcium carbonate mineral formation in surface and ground water. To better understand DOM mediation of carbonate precipitation and DOM co-precipitation and/or incorporation with carbonate minerals, we characterized the content and speciation of DOM in carbonate minerals and in the lake water of Pyramid Lake, Nevada, USA. A 400-gram block of precipitated calcium carbonate from the Pyramid Lake shore was dissolved in 8 liters of 10% acetic acid. Particulate matter not dissolved by acetic acid was removed by centrifugation. DOM from the carbonate rock was fractionated into nine portions using evaporation, dialysis, resin adsorption, and selective precipitations to remove acetic acid and inorganic constituents. The calcium carbonate rock contained 0.23% DOM by weight. This DOM was enriched in polycarboxylic proteinaceous acids and hydroxy-acids in comparison with the present lake water. DOM in lake water was composed of aliphatic, alicyclic polycarboxylic acids. These compound classes were found in previous studies to inhibit calcium carbonate precipitation. DOM fractions from the carbonate rock were 14C-age dated at about 3,100 to 3,500 years before present. The mechanism of DOM co-precipitation and/or physical incorporation in the calcium carbonate is believed to be due to formation of insoluble calcium complexes with polycarboxylic proteinaceous acids and hydroxy-acids that have moderately large stability constants at the alkaline pH of the lake. DOM co-precipitation with calcium carbonate and incorporation in precipitated carbonate minerals removes proteinaceous DOM, but nearly equivalent concentrations of neutral and acidic forms of organic nitrogen in DOM remain in solution. Calcium carbonate precipitation during lime softening pretreatment of drinking water may have practical applications for removal of proteinaceous disinfection by-product precursors.

Holocene environmental changes inferred from biological and sedimentological proxies in a high elevation Great Basin lake in the northern Ruby Mountains, Nevada, USA

USGS Publications Warehouse

Wahl, David B.; Starratt, Scott W.; Anderson, Lysanna; Kusler, Jennifer E.; Fuller, Christopher C.; Addison, Jason A.; Wan, Elmira

2015-01-01

Multi-proxy analyses were conducted on a sediment core from Favre Lake, a high elevation cirque lake in the northern Ruby Mountains, Nevada, and provide a ca. 7600 year record of local and regional environmental change. Data indicate that lake levels were lower from 7600-5750 cal yr BP, when local climate was warmer and/or drier than today. Effective moisture increased after 5750 cal yr BP and remained relatively wet, and possibly cooler, until ca. 3750 cal yr BP. Results indicate generally dry conditions but also enhanced climatic variability from 3750-1750 cal yr BP, after which effective moisture increased. The timing of major changes in the Favre Lake proxy data are roughly coeval and in phase with those recorded in several paleoclimate studies across the Great Basin, suggesting regional climatic controls on local conditions and similar responses at high and low altitudes.

Chronology for fluctuations in late Pleistocene Sierra Nevada glaciers and lakes

USGS Publications Warehouse

Phillips, F.M.; Zreda, M.G.; Benson, L.V.; Plummer, M.A.; Elmore, D.; Sharma, Prakash

1996-01-01

Mountain glaciers, because of their small size, are usually close to equilibrium with the local climate and thus should provide a test of whether temperature oscillations in Greenland late in the last glacial period are part of global-scale climate variability or are restricted to the North Atlantic region. Correlation of cosmogenic chlorine-36 dates on Sierra Nevada moraines with a continuous radiocarbon-dated sediment record from nearby Owens Lake shows that Sierra Nevada glacial advances were associated with Heinrich events 5, 3, 2, and 1.

Crustal structure between Lake Mead, Nevada, and Mono Lake, California

USGS Publications Warehouse

Johnson, Lane R.

1964-01-01

Interpretation of a reversed seismic-refraction profile between Lake Mead, Nevada, and Mono Lake, California, indicates velocities of 6.15 km/sec for the upper layer of the crust, 7.10 km/sec for an intermediate layer, and 7.80 km/sec for the uppermost mantle. Phases interpreted to be reflections from the top of the intermediate layer and the Mohorovicic discontinuity were used with the refraction data to calculate depths. The depth to the Moho increases from about 30 km near Lake Mead to about 40 km near Mono Lake. Variations in arrival times provide evidence for fairly sharp flexures in the Moho. Offsets in the Moho of 4 km at one point and 2 1/2 km at another correspond to large faults at the surface, and it is suggested that fracture zones in the upper crust may displace the Moho and extend into the upper mantle. The phase P appears to be an extension of the reflection from the top of the intermediate layer beyond the critical angle. Bouguer gravity, computed for the seismic model of the crust, is in good agreement with the measured Bouguer gravity. Thus a model of the crustal structure is presented which is consistent with three semi-independent sources of geophysical data: seismic-refraction, seismic-reflection, and gravity.

Back to the Basics: Lake Tahoe, California/Nevada--Spatial Measurement

ERIC Educational Resources Information Center

Handley, Lawrence R.; Lockwood, Catherine M.; Handley, Nathan

2006-01-01

"Back to the Basics: South Lake Tahoe, California/Nevada" continues the series of exercises on teaching foundational map reading and spatial differentiation skills. It is the third published exercise from the Back to the Basics series developed by the Wetland Education through Maps and Aerial Photography (WETMAAP) Program. The current…

Changes in High Elevation Lake Ecosystems of the Sierra Nevada during the 20th Century: Combining Long-term Monitoring with Paleolimnology

NASA Astrophysics Data System (ADS)

Sickman, J. O.; Heard, A. M.; Rose, N. L.; Bennett, D. M.; Lucero, D. M.; Melack, J. M.; Curtis, J. H.

2014-12-01

High mountain lakes of the Sierra Nevada are excellent indicators of anthropogenic global change due to their limited capacity to buffer acid deposition, their sensitivity to changes in snowpack dynamics and their oligotrophic nutrient status. In this presentation, we examine long-term records of hydrochemistry and biological monitoring at the Emerald Lake watershed to assess whether high elevation lakes of the Sierra Nevada are changing in response to climate change or changes in atmospheric deposition of nutrients and acid. To provide a broader context for these changes, we augment these long-term records with results from paleolimnological analysis that examines changes in nutrient status and acid buffering capacity of Sierra Nevada lakes over the past two millennia. Our research suggests that, although atmospheric deposition is the dominant driver of twentieth century ANC trends, aquatic communities in the Sierra Nevada are responding to combined effects from acidification, climate change, and eutrophication. Early in the twentieth century the primary stressor effecting Sierra Nevada lakes was acid deposition driven by SO2 emissions. As the century and industrialization progressed, NOx levels increased adding a eutrophication stressor while simultaneously contributing to acidification. Effects were further complicated by a warming climate in the late twentieth century, as warmer temperatures may have contributed to the recovery of ANC in lakes via increased weathering rates, while simultaneously enhancing eutrophication effects.

Uranium in Holocene valley-fill sediments, and uranium, radon, and helium in waters, Lake Tahoe-Carson Range area, Nevada and California, U.S.A.

USGS Publications Warehouse

Otton, J.K.; Zielinski, R.A.; Been, J.M.

1989-01-01

Uraniferous Holocene sediments occur in the Carson Range of Nevada and California, U.S.A., between Lake Tahoe and Carson Valley. The hosts for the uranium include peat and interbedded organic-rich sand, silt, and mud that underly valley floors, fens, and marshes along stream valleys between the crest of the range and the edge of Lake Tahoe. The known uranium accumulations extend along the Carson Range from the area just southeast of South Lake Tahoe northward to the area just east of Carson City; however, they almost certainly continue beyond the study area to the north, west, and south. Due to the young age of the accumulations, uranium in them is in gross disequilibrium with its highly radioactive daughter products. These accumulations have thus escaped discovery with radiation detection equipment in the past. The uranium content of these sediments approaches 0.6 percent; however, the average is in the range of 300-500 ppm. Waters associated with these sediments locally contain as much as 177 ppb uranium. Modest levels of helium and radon also occur in these waters. Uraniferous waters are clearly entering the private and public water supply systems in some parts of the study area; however, it is not known how much uranium is reaching users of these water supplies. Many of the waters sampled in the study area exceed the published health effects guidance level of the Environmental Protection Agency. Regulatory standards for uranium in waters have not been published, however. Much uranium is stored in the sediments along these stream valleys. Estimates for a marsh and a fen along one drainage are 24,000 and 15,000 kg, respectively. The potential effects of man-induced environmental changes on the uranium are uncertain. Laboratory studies of uraniferous sediment rich in organic matter may allow us to evaluate the potential of liberating uranium from such sediments and creating transient increases in the level of uranium moving in water in the natural environment

Investigating the Seismicity and Stress Field of the Truckee -- Lake Tahoe Region, California -- Nevada

NASA Astrophysics Data System (ADS)

Seaman, Tyler

The Lake Tahoe basin is located in a transtensional environment defined by east-dipping range--bounding normal faults, northeast--trending sinistral, and northwest-trending dextral strike-slip faults in the northern Walker Lane deformation belt. This region accommodates as much as 10 mm/yr of dextral shear between the Sierra Nevada and Basin and Range proper, or about 20% of Pacific-North American plate motion. There is abundant seismicity north of Lake Tahoe through the Truckee, California region as opposed to a lack of seismicity associated with the primary normal faults in the Tahoe basin (i.e., West Tahoe fault). This seismicity study is focused on the structural transition zone from north-striking east-dipping Sierran Range bounding normal faults into the northern Walker Lane right-lateral strike-slip domain. Relocations of earthquakes between 2000-2013 are performed by initially applying HYPOINVERSE mean sea level datum and station corrections to produce higher confidence absolute locations as input to HYPODD. HYPODD applies both phase and cross-correlation times for a final set of 'best' event relocations. Relocations of events in the upper brittle crust clearly align along well-imaged, often intersecting, high-angle structures of limited lateral extent. In addition, the local stress field is modeled from 679 manually determined short-period focal mechanism solutions, between 2000 and 2013, located within a fairly dense local seismic network. Short-period focal mechanisms were developed with the HASH algorithm and moment tensor solutions using long-period surface waves and the MTINV code. Resulting solutions show a 9:1 ratio of strike-slip to normal mechanisms in the transition zone study area. Stress inversions using the application SATSI (USGS Spatial And Temporal Stress Inversion) generally show a T-axis oriented primarily E-W that also rotates about 30 degrees counterclockwise, from a WNW-ESE trend to ENE-WSW, moving west to east across the California--Nevada

Pleistocene lake outburst floods and fan formation along the eastern Sierra Nevada, California: implications for the interpretation of intermontane lacustrine records

NASA Astrophysics Data System (ADS)

Benn, Douglas I.; Owen, Lewis A.; Finkel, Robert C.; Clemmens, Samuel

2006-11-01

Variations in the rock flour fraction in intermontane lacustrine sediments have the potential to provide more complete records of glacier fluctuations than moraine sequences, which are subject to erosional censoring. Construction of glacial chronologies from such records relies on the assumption that rock flour concentration is a simple function of glacier extent. However, other factors may influence the delivery of glacigenic sediments to intermontane lakes, including paraglacial adjustment of slope and fluvial systems to deglaciation, variations in precipitation and snowmelt, and lake outburst floods. We have investigated the processes and chronology of sediment transport on the Tuttle and Lone Pine alluvial fans in the eastern Sierra Nevada, California, USA, to elucidate the links between former glacier systems located upstream and the long sedimentary record from Owens Lake located downstream. Aggradation of both fans reflects sedimentation by three contrasting process regimes: (1) high magnitude, catastrophic floods, (2) fluvial or glacifluvial river systems, and (3) debris flows and other slope processes. Flood deposits are represented by multiple boulder beds exposed in section, and extensive networks of large palaeochannels and boulder deposits on both fan surfaces. Palaeohydrological analysis implies peak discharges in the order of 10 3-10 4 m 3 s -1, most probably as the result of catastrophic drainage of ice-, moraine-, and landslide-dammed lakes. Cosmogenic radionuclide surface exposure dating shows that at least three flood events are represented on each fan, at 9-13, 16-18 and 32-44 ka (Tuttle Fan); and at ˜23-32, ˜80-86 ka, and a poorly constrained older event (Lone Pine Fan). Gravels and sands exposed in both fans represent fluvial and/or glacifluvial sediment transport from the Sierra Nevada into Owens Valley, and show that river systems incised and reworked older sediment stored in the fans. We argue that millennial-scale peaks in rock flour

Do High-elevation Lakes Record Variations in Snowfall and Atmospheric Rivers in the Sierra Nevada of California?

NASA Astrophysics Data System (ADS)

Ashford, J.; Sickman, J. O.; Lucero, D. M.

2014-12-01

Understanding the underlying causes of interannual variation in snowfall and extreme hydrologic events in the Sierra Nevada is hampered by short instrumental records and the difficulties in reconstructing climate using a traditional paleo-record such as tree-rings. New paleo proxies are needed to provide a record of snowpack water content and extreme precipitation events over millennial timescales which can be used to test hypotheses regarding teleconnections between Pacific climate variability and water supply and flood risk in California. In October 2013 we collected sediment cores from Pear Lake (z = 27 m), an alpine lake in Sequoia National Park. The cores were split and characterized by P-wave velocity, magnetic susceptibility and density scanning. Radiocarbon dates indicate that the Pear Lake cores contain a 13.5K yr record of lake sediment. In contrast to other Sierra Nevada lakes previously cored by our group, high-resolution scanning revealed alternating light-dark bands (~1 mm to 5 mm thick) for most of the Pear Lake core length. This pattern was interrupted at intervals by homogenous clasts (up to 75 mm thick) ranging in grain size from sand to gravel up to 1 cm diameter. We hypothesize that the light-dark banding results from the breakdown of persistent hypolimnetic anoxia during spring snowmelt and autumn overturn. We speculate that the thicknesses of the dark bands are controlled by the duration of anoxia which in turn is controlled by the volume and duration of snowmelt. The sand to gravel sized clasts are most likely associated with extreme precipitation events resulting from atmospheric rivers intersecting the southern Sierra Nevada. We hypothesize that centimeter-sized clasts are deposited in large avalanches and that the sands are deposited in large rain events outside of the snow-cover period.

Bathymetry of Walker Lake, West-Central Nevada

USGS Publications Warehouse

Lopes, Thomas J.; Smith, J. LaRue

2007-01-01

Walker Lake lies within a topographically closed basin in west-central Nevada and is the terminus of the Walker River. Much of the streamflow in the Walker River is diverted for irrigation, which has contributed to a decline in lake-surface altitude of about 150 feet and an increase in dissolved solids from 2,500 to 16,000 milligrams per liter in Walker Lake since 1882. The increase in salinity threatens the fresh-water ecosystem and survival of the Lahontan cutthroat trout, a species listed as threatened under the Endangered Species Act. Accurately determining the bathymetry and relations between lake-surface altitude, surface area, and storage volume are part of a study to improve the water budget for Walker Lake. This report describes the updated bathymetry of Walker Lake, a comparison of results from this study and a study by Rush in 1970, and an estimate of the 1882 lake-surface altitude. Bathymetry was measured using a single-beam echosounder coupled to a differentially-corrected global positioning system. Lake depth was subtracted from the lake-surface altitude to calculate the altitude of the lake bottom. A Lidar (light detection and ranging) survey and high resolution aerial imagery were used to create digital elevation models around Walker Lake. The altitude of the lake bottom and digital elevation models were merged together to create a single map showing land-surface altitude contours delineating areas that are currently or that were submerged by Walker Lake. Surface area and storage volume for lake-surface altitudes of 3,851.5-4,120 feet were calculated with 3-D surface-analysis software. Walker Lake is oval shaped with a north-south trending long axis. On June 28, 2005, the lake-surface altitude was 3,935.6 feet, maximum depth was 86.3 feet, and the surface area was 32,190 acres. The minimum altitude of the lake bottom from discrete point depths is 3,849.3 feet near the center of Walker Lake. The lake bottom is remarkably smooth except for mounds near

My Favorite Assignment: Selections from the ABC 2008 Annual Convention, Lake Tahoe, Nevada

ERIC Educational Resources Information Center

Whalen, D. Joel, Ed.

2009-01-01

At the 2008 Association for Business Communication (ABC) annual convention in Lake Tahoe, Nevada, many attendees stood at the back of a crowded room to hear over a dozen teachers describe "My Favorite Assignment." As is customary in these lively sessions, the chair, Dan Dieterich, orchestrated a fast, efficient presentation pace; each…

Effects on nonnative fishes on wilderness lake ecosystems in the Sierra Nevada and recommendations for reducing impacts

Treesearch

R. A. Knapp; Kathleen R. Matthews

2000-01-01

Wilderness areas of the Sierra Nevada, California contain thousands of lakes and ponds, nearly all of which were historically fishless. After more than a century of fish stocking, introduced trout are now present in up to 80% of larger lakes. These nonnative fishes have had profound impacts on native fishes, amphibians, and invertebrates. Several of these native...

The aqueous geochemistry of uranium in a drainage containing uraniferous organic-rich sediments, Lake Tahoe area, Nevada, USA

USGS Publications Warehouse

Zielinski, R.A.; Otton, J.K.; Wanty, R.B.; Pierson, C.T.

1988-01-01

Anomalously uraniferous waters occur in a small (4.2 km2) drainage in the west-central Carson Range, Nevada, on the eastern side of Lake Tahoe. The waters transport uranium from local U-rich soils and bedrock to organic-rich valley-fill sediments where it is concentrated, but weakly bound. The dissolved U and the U that is potentially available from coexisting sediments pose a threat to the quality of drinking water that is taken from the drainage. The U concentration in samples of 6 stream, 11 spring and 7 near-surface waters ranged from 0.1 V). Possible precipitation of U(IV) minerals is predicted under the more reducing conditions that are particularly likely in near-surface waters, but the inhibitory effects of sluggish kinetics or organic complexing are not considered. These combined results suggest that a process such as adsorption or ion exchange, rather than mineral saturation, is the most probable mechanism for uranium fixation in the sediments. -Authors

Hydrogeochemistry of Big Soda Lake, Nevada: An alkaline meromictic desert lake

USGS Publications Warehouse

Kharaka, Y.K.; Robinson, S.W.; Law, L.M.; Carothers, W.W.

1984-01-01

Big Soda Lake, located near Fallon, Nevada, occupies an explosion crater rimmed by basaltic debris; volcanic activity apparently ceased within the last 10,000 years. This lake has been selected for a detailed multidisciplinary study that will ultimately cover the organic and inorganic hydrogeochemistry of water and sediments because the time at which chemical stratification was initiated is known (~1920) and chemical analyses are available for a period of more than 100 years. Detailed chemical analyses of the waters show that the lake is at present alkaline (pH = 9.7), chemically stratified (meromictic) and is extremely anoxic (total reduced sulfur-410 mg/L as H2S) below a depth of about 35 m. The average concentrations (in mg/L) of Na, K, Mg, Ca, NH3, H2S, alkalinity (as HCO3), Cl, SO4, and dissolved organics (as C) in waters of the upper layer (depth 0 to 32 m) are 8,100, 320, 150, 5.0, < 0.1, < 0.5, 4,100, 7,100, 5,800, and 20 respectively; in the deeper layer (depth 37 to 64 m) they are 27,000, 1,200, 5.6, 0.8, 45, 410, 24,000, 27,500, 6,800, and 60, respectively. Chemical and stable isotope analyses of the waters, ??13C and ??14C values of dissolved total carbonate from this lake and surface and ground waters in the area together with mineral-water equilibrium computations indicate that the waters in the lake are primarily meteoric in origin with the present chemical composition resulting from the following geochemical processes: 1. (1) evaporation and exchange with atmosphere, the dominant processes, 2. (2) mineral-water interactions, including dissolution, precipitation and ion exchange, 3. (3) inflow and outflow of ground water and 4. (4) biological activity of macro- and microorganisms, including sulfate reduction in the water column of the deeper layer at a very high rate of 6.6 ??mol L-1 day-1. ?? 1984.

Application of an extreme winter storm scenario to identify vulnerabilities, mitigation options, and science needs in the Sierra Nevada mountains, USA

USGS Publications Warehouse

Albano, Christine M.; Dettinger, Michael; McCarthy, Maureen; Schaller, Kevin D.; Wellborn, Toby; Cox, Dale A.

2016-01-01

In the Sierra Nevada mountains (USA), and geographically similar areas across the globe where human development is expanding, extreme winter storm and flood risks are expected to increase with changing climate, heightening the need for communities to assess risks and better prepare for such events. In this case study, we demonstrate a novel approach to examining extreme winter storm and flood risks. We incorporated high-resolution atmospheric–hydrologic modeling of the ARkStorm extreme winter storm scenario with multiple modes of engagement with practitioners, including a series of facilitated discussions and a tabletop emergency management exercise, to develop a regional assessment of extreme storm vulnerabilities, mitigation options, and science needs in the greater Lake Tahoe region of Northern Nevada and California, USA. Through this process, practitioners discussed issues of concern across all phases of the emergency management life cycle, including preparation, response, recovery, and mitigation. Interruption of transportation, communications, and interagency coordination were among the most pressing concerns, and specific approaches for addressing these issues were identified, including prepositioning resources, diversifying communications systems, and improving coordination among state, tribal, and public utility practitioners. Science needs included expanding real-time monitoring capabilities to improve the precision of meteorological models and enhance situational awareness, assessing vulnerabilities of critical infrastructure, and conducting cost–benefit analyses to assess opportunities to improve both natural and human-made infrastructure to better withstand extreme storms. Our approach and results can be used to support both land use and emergency planning activities aimed toward increasing community resilience to extreme winter storm hazards in mountainous regions.

Sierra Nevada, California

NASA Image and Video Library

1994-09-30

STS068-267-097 (30 September-11 October 1994) --- An extensive view eastward from the irrigated San Joaquin Valley in the foreground, across the Sierra Nevada (living up to its name in early October), into the desert of eastern California and Nevada (which has no snow, despite the name). Mono Lake is just visible at the left edge of the frame; Owens Valley extends southward to Owens Lake, the next valley is Panamint Valley, and then Death Valley. Las Vegas and Lake Mead are visible at the upper right of the frame. The Space Radar Laboratory 2 (SRL-2) obtained extensive, multiple-pass data from many test sites within the region displayed, including Mammoth Mountain ski area south of Mono Lake, and in Death Valley.

Exceptionally fast growth rate of <100-yr-old tufa, Big Soda Lake, Nevada: Implications for using tufa as a peleoclimate proxy

USGS Publications Warehouse

Rosen, Michael R.; Arehart, G.B.; Lico, M.S.

2004-01-01

Large tufa mounds (>3 m tall, with a basal circumference of 5 m) have been discovered on the margin of Big Soda Lake, Nevada, USA. These tufa mounds are rooted at a maximum of 4 m below the current lake surface and are actively forming from groundwater seepage, which can be seen emanating from the top of the tufa mounds. Big Soda Lake is a volcanic crater lake whose water level is maintained exclusively by groundwater. The age of the tufa mounds is well constrained because prior to the development of the Newlands Irrigation Project in 1907, the water level was ???18 m lower than the current lake level. The vertical columnar nature of the tufa mounds indicates that they formed under the lake and not subaerially. Thus, the tufa mounds are <100 yr old and have grown at a rate ???30 mm/yr. Stable oxygen and carbon isotope analyses of tufa carbonate compared to isotopic analyses of groundwater and lake water and hydrochemical data indicate that the fluids responsible for their precipitation are a simple mixture of modern groundwater and lake water and do not reflect a recent climate signature. The exceptionally fast growth of the tufa mounds indicates that large tufa deposits may form almost instantaneously in geologic time. Given this potential for rapid growth and the fact that variations in isotopic compositions of tufa deposits have been interpreted in terms of changes in paleoclimate and changes in the composition of recharge water over thousands of years, care should be taken when trying to determine the significance of variations in isotopic or chemical compositions of tufas that may have been caused by mixing with groundwater. ?? 2004 Geological Society of America.

Near-surface geophysical characterization of Holocene faults conducive to geothermal flow near Pyramid Lake, Nevada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dudley, Colton; Dorsey, Alison; Louie, John

Colton Dudley, Alison Dorsey, Paul Opdyke, Dustin Naphan, Marlon Ramos, John Louie, Paul Schwering, and Satish Pullammanappallil, 2013, Near-surface geophysical characterization of Holocene faults conducive to geothermal flow near Pyramid Lake, Nevada: presented at Amer. Assoc. Petroleum Geologists, Pacific Section Annual Meeting, Monterey, Calif., April 19-25.

Chlorophyll maxima in mountain ponds and lakes, Mount Rainier National Park, Washington State, USA

USGS Publications Warehouse

Larson, Gary L.

2000-01-01

Hypolimnetic chlorophyll maxima are common in clear lakes and often occur at depths with between 1 and 0.1% of the surface incident light. Little is known, however, about the concentrations of chlorophyll in thermally unstratified mountain ponds and how these concentrations compare to epilimnetic and hypolimnetic concentrations in mountain lakes. The objectives of this study were to document the concentrations of chlorophyll in thermally unstratified ponds and stratified lakes in Mount Rainier National Park (MORA) and to compare the results with concentrations and distributions of chlorophyll in clear-deep lakes in the Oregon Cascade Range and the Sierra Nevada Range. Thirty-two ponds (<2.5 m deep) and 14 lakes(>9.9 m deep) were sampled primarily during the summers of 1992 to 1996 at MORA. Water samples from near the surface (0.1–0.5 m) of ponds and near the surface and near the bottom of lakes were collected over the deepest part of each system. One exception, Mowich Lake, was sampled at seven depths between the surface and 50 m (Z=58.6 m). Chlorophyll concentrations were low in all systems, but higher in ponds (average 1.8 μg·L−1) than in lakes. Chlorophyll concentrations were higher in hypolimnetic lake samples (average 0.7 μg·L−1) than in epilimnetic lake samples (average 0.2 μg·L−1). Elevated concentrations of chlorophyll in mountain ponds, relative to those in hypolimnetic lake samples, may have been influenced by increased nutrient availability from interactions at the mud-water interface and, in this park, defecation by elk that used many of the ponds as wallows. Mowich Lake showed a chlorophyll maximum (~1.5 μg·L−1) near the lake bottom. Based on Secchi disk clarity readings, the depth of 1.0% incident surface solar radiation was greater than the maximum depths of the ponds and lakes. Comparative data from other clear-deep lakes in the Oregon Cascade Range and Sierra Nevada Range suggested that deep-chlorophyll maxima (~1.5 μg·L−1

Critical Loads of Acid Deposition for Wilderness Lakes in the Sierra Nevada (California) Estimated by the Steady-State Water Chemistry Model

Treesearch

Glenn D. Shaw; Ricardo Cisneros; Donald Schweizer; James O. Sickman; Mark E. Fenn

2014-01-01

Major ion chemistry (2000-2009) from 208 lakes (342 sample dates and 600 samples) in class I and II wilderness areas of the Sierra Nevada was used in the Steady-State Water Chemistry (SSWC) model to estimate critical loads for acid deposition and investigate the current vulnerability of high elevation lakes to acid deposition. The majority of the lakes were dilute (...

D/H Ratios From Sierra Nevada Varved Lake Sediments Record Decadal Hydroclimate Variability During The Medieval Period

NASA Astrophysics Data System (ADS)

Roach, L. D.; Cayan, D. R.; Sessions, A. L.; Charles, C. D.; Anderson, R. S.

2009-12-01

Assessment of the risks of persistent drought requires multiple realizations of decadal and centennial scale hydroclimate variability that extend beyond the relatively short period of instrumental record. Much remains to be learned about the so called “mega droughts” in the Sierra Nevada Mountains, where various lines of evidence point toward the occurrence of severe, decades-long droughts during Medieval times, approximately 900-1400 AD. Here we present a continuous, decadal scale record of hydroclimate variability in the Sierra Nevada Mountains that extends through the heart of the purported Medieval mega droughts. Previous work on the stable hydrogen isotope (D/H) ratios of refractory plant lipid compounds stored in lake sediments demonstrated that these compounds reflect the D/H values of lake water and/or shallow ground water--reservoirs both fed by local precipitation. Lake sediment D/H can therefore reflect the processes that determine D/H of precipitation, including temperature, humidity and moisture source. We have measured D/H of aquatic and terrestrial plant fatty acids extracted from a suite of sediment cores collected at Swamp Lake (elevation: 1554m), in Yosemite National Park, along the Sierra Nevada crest. Measurements with biennial resolution were made for two time periods: the 20th century and the 13th-15th centuries. D/H fluctuations in 20th century sediment contain relatively strong decadal structure. Comparison with instrumentally recorded climate variability reveals that lower D/H concentrations are associated with years of higher than normal annual precipitation, cooler than normal wintertime temperatures, and positive April 1 Snow Water Equivalent (SWE) anomalies throughout the Sierra Nevada, (and conversely for elevated D/H concentrations). The range of variability is approximately 50‰. These associations may be driven by the variable mass-balance impact of evaporation on the isotopic composition of lake water and shallow groundwater

Modeling spatial and temporal variations in temperature and salinity during stratification and overturn in Dexter Pit Lake, Tuscarora, Nevada, USA

USGS Publications Warehouse

Balistrieri, L.S.; Tempel, R.N.; Stillings, L.L.; Shevenell, L.A.

2006-01-01

This paper examines the seasonal cycling of temperature and salinity in Dexter pit lake in arid northern Nevada, and describes an approach for modeling the physical processes that operate in such systems. The pit lake contains about 596,200 m3 of dilute, near neutral (pHs 6.7-9) water. Profiles of temperature, conductivity, and selected element concentrations were measured almost monthly during 1999 and 2000. In winter (January-March), the pit lake was covered with ice and bottom water was warmer (5.3 ??C) with higher total dissolved solids (0.298 g/L) than overlying water (3.96 ??C and 0.241 g/L), suggesting inflow of warm (11.7 ??C) groundwater with a higher conductivity than the lake (657 versus 126-383 ??S/cm). Seasonal surface inflow due to spring snowmelt resulted in lower conductivity in the surface water (232-247 ??S/cm) relative to deeper water (315-318 ??S/cm). The pit lake was thermally stratified from late spring through early fall, and the water column turned over in late November (2000) or early December (1999). The pit lake is a mixture of inflowing surface water and groundwater that has subsequently been evapoconcentrated in the arid environment. Linear relationships between conductivity and major and some minor (B, Li, Sr, and U) ions indicate conservative mixing for these elements. Similar changes in the elevations of the pit lake surface and nearby groundwater wells during the year suggest that the pit lake is a flow-through system. This observation and geochemical information were used to configure an one-dimensional hydrodynamics model (Dynamic Reservoir Simulation Model or DYRESM) that predicts seasonal changes in temperature and salinity based on the interplay of physical processes, including heating and cooling (solar insolation, long and short wave radiation, latent, and sensible heat), hydrologic flow (inflow and outflow by surface and ground water, pumping, evaporation, and precipitation), and transfers of momentum (wind stirring

A fan dam for Tulare Lake, California, and implications for the Wisconsin glacial history of the Sierra Nevada.

USGS Publications Warehouse

Atwater, B.F.

1986-01-01

Four stratigraphically consistent 14C dates on peat and wood give an age of 26 000 yr BP for the start of Tulare Lake's late Wisconsin transgression. An earlier enlargement of Tulare Lake probably resulted from a fan dam produced by the penultimate major (Tahoe) glaciation of the Sierra Nevada. Average sedimentation rates inferred from depths to a 600 000-yr-old clay and from radiocarbon dates indicate that this earlier lake originated no later than 100 000 yr BP. The Tahoe glaciation therefore is probably pre- Wisconsin. -from Authors

Geochemical evolution of Great Salt Lake, Utah, USA

USGS Publications Warehouse

Jones, B.F.; Naftz, D.L.; Spencer, R.J.; Oviatt, Charles G.

2009-01-01

The Great Salt Lake (GSL) of Utah, USA, is the largest saline lake in North America, and its brines are some of the most concentrated anywhere in the world. The lake occupies a closed basin system whose chemistry reflects solute inputs from the weathering of a diverse suite of rocks in its drainage basin. GSL is the remnant of a much larger lacustrine body, Lake Bonneville, and it has a long history of carbonate deposition. Inflow to the lake is from three major rivers that drain mountain ranges to the east and empty into the southern arm of the lake, from precipitation directly on the lake, and from minor groundwater inflow. Outflow is by evaporation. The greatest solute inputs are from calcium bicarbonate river waters mixed with sodium chloride-type springs and groundwaters. Prior to 1930 the lake concentration inversely tracked lake volume, which reflected climatic variation in the drainage, but since then salt precipitation and re-solution, primarily halite and mirabilite, have periodically modified lake-brine chemistry through density stratification and compositional differentiation. In addition, construction of a railway causeway has restricted circulation, nearly isolating the northern from the southern part of the lake, leading to halite precipitation in the north. These and other conditions have created brine differentiation, mixing, and fractional precipitation of salts as major factors in solute evolution. Pore fluids and diagenetic reactions have been identified as important sources and especially sinks for CaCO3, Mg, and K in the lake, depending on the concentration gradient and clays. ?? U.S. Geological Survey 2008.

Nutrient Fluxes From Profundal Sediment of Ultra-Oligotrophic Lake Tahoe, California/Nevada: Implications for Water Quality and Management in a Changing Climate

NASA Astrophysics Data System (ADS)

Beutel, Marc W.; Horne, Alexander J.

2018-03-01

A warming climate is expected to lead to stronger thermal stratification, less frequent deep mixing, and greater potential for bottom water anoxia in deep, temperate oligotrophic lakes. As a result, there is growing interest in understanding nutrient cycling at the profundal sediment-water interface of these rare ecosystems. This paper assessed nutrient content and nutrient flux rates from profundal sediment at Lake Tahoe, California/Nevada, USA. Sediment is a large reservoir of nutrients, with the upper 5 cm containing reduced nitrogen (˜6,300 metric tons) and redox-sensitive phosphorus (˜710 metric tons) equivalent to ˜15 times the annual external load. Experimental results indicate that if deep water in Lake Tahoe goes anoxic, profundal sediment will release appreciable amounts of phosphate (0.13-0.29 mg P/m2·d), ammonia (0.49 mg N/m2·d), and iron to overlaying water. Assuming a 10 year duration of bottom water anoxia followed by a deep-water mixing event, water column phosphate, and ammonia concentrations would increase by an estimated 1.6 µg P/L and 2.9 µg N/L, nearly doubling ambient concentrations. Based on historic nutrient enrichment assays this could lead to a ˜40% increase in algal growth. Iron release could have the dual effect of alleviating nitrate limitation on algal growth while promoting the formation of fine iron oxyhydroxide particles that degrade water clarity. If the depth and frequency of lake mixing decrease in the future as hydrodynamic models suggest, large-scale in-lake management strategies that impede internal nutrient loading in Lake Tahoe, such as bottom water oxygen addition or aluminum salt addition, may need to be considered.

Antiparasitic and antimicrobial indolizidines from the leaves of Prosopis glandulosa var glandulosa from Nevada and Texas USA

USDA-ARS?s Scientific Manuscript database

A new indolizidine alkaloid, named (Delta) 1,6-juliprosopine (1), together with previously known indolizidine analogs (2-6), was isolated from the leaves of Prosopis glandulosa var. glandulosa, collected from Nevada, USA; while two other known indolizidines juliprosopine (6) and juliprosine (7) were...

Bathymetric and geophysical surveys of Englebright Lake, Yuba-Nevada Counties, California

USGS Publications Warehouse

Childs, Jonathan R.; Snyder, Noah P.; Hampton, Margaret A.

2003-01-01

Harry L. Englebright Lake is a 9-mile-long (14-kilometer) reservoir located in the Sierra Nevada foothills of northern California on the Yuba River gorge known as The Narrows. The reservoir is impounded by Englebright Dam (Photo 1), a concrete arch structure spanning 348 meters (1,142 feet) across and 79 meters (260 feet) high. The dam was constructed in 1941 for the primary purpose of trapping sediment derived from anticipated hydraulic mining operations in the Yuba River watershed. Hydraulic mining in the Sierra Nevada was halted in 1884 but resumed on a limited basis until the 1930's under the regulation of the California Debris Commission. Although no hydraulic mining in the upper Yuba River watershed resumed after the construction of the dam, the historical mine sites continued to contribute sediment to the river. Today, Englebright Lake is used primarily for recreation and hydropower. In 2001 and 2002, the U.S. Geological Survey (USGS) conducted bathymetric, geophysical, and geological studies of the reservoir under the auspices of the Upper Yuba River Studies Program (UYRSP), a multi-disciplinary investigation into the feasibility of introducing anadromous fish species to the Yuba River system upstream of Englebright Dam. A primary purpose of these studies was to assess the quantity and nature of the sediment that has accumulated behind the dam over the past 60 years. This report presents the results of those surveys, including a new bathymetric map of the reservoir and estimates of the total accumulated sediment volume.

Distribution, abundance and carbon isotopic composition of gaseous hydrocarbons in Big Soda Lake, Nevada - An alkaline, meromictic lake

NASA Technical Reports Server (NTRS)

Oremland, R. S.; Des Marais, D. J.

1983-01-01

The study of the distribution and isotopic composition of low molecular weight hydrocarbon gases at the Big Soda Lake, Nevada, has shown that while neither ethylene nor propylene were found in the lake, ethane, propane, isobutane and n-butane concentrations all increased with water column depth. It is concluded that methane has a biogenic origin in both the sediments and the anoxic water column, and that C2-C4 alkanes have biogenic origins in the monimolimnion water and shallow sediments. The changes observed in delta C-13/CH4/ and CH4/(C2H6 + C3H8) with depth in the water column and sedimeents are probably due to bacterial processes, which may include anaerobic methane oxidation and different rates of methanogenesis, and C2-to-C4 alkane production by microorganisms.

Secondary Pollutants in the Lake Tahoe Basin, USA

NASA Astrophysics Data System (ADS)

Zielinska, B.; Bytnerowicz, A.; Gertler, A.; McDaniel, M.; Burley, J. D.

2013-12-01

Lake Tahoe, located at 6,225 ft. (1,897 m) in the Sierra Nevada mountain range, is the largest alpine lake in North America. Known for the clarity of its water and the panorama of surrounding mountains on all sides, Lake Tahoe is a prime tourist attraction in the California - Nevada area. However, the Lake Tahoe Basin is facing significant problems in air quality and declining water clarity. In July 21 - 26, 2012, we conducted a field study in the Basin designed to characterize the precursors and pathways of secondary pollutant formation, including ozone, secondary organic aerosol (SOA) and ammonium nitrate. Four strategic sampling sites were selected inside the Basin; two of these sites were located at high elevation (one each on the western and eastern sides of the Basin) and two were positioned near the Lake level. Ozone and NO/NO2 concentrations were continuously measured. With a resolution of several hours over a 6-day sampling period we collected canister samples for detailed speciation of volatile organic compounds (VOC), 2,4-dinitrophenylhydrazine (DNPH) impregnated Sep-Pak cartridges for analysis of carbonyl compounds and honeycomb denuder/filter pack samples for measurement of concentrations of ammonia, nitrous acid, nitric acid, and fine particulate ammonium nitrate. We also collected PM2.5 Teflon and quartz filter samples for measurements of mass, organic and elemental carbon (OC/EC) concentrations and speciation of organic compounds. Whereas the concentrations of lower molecular weight (mw) C2 - C3 hydrocarbons were generally the highest in all sampling sites, ranging from 25 to 76% of the total measured VOC (over 70 species from C2 to C10), the concentrations of biogenic hydrocarbons, isoprene and α-pinene were significant, ranging from 1.4 to 26% and 1.5 to 30%, respectively, of the total VOC, depending on the site and sampling period. For comparison, the sum of benzene, toluene, ethylbenzene and xylenes (BTEX) constituted from 2.5 to 37% of the

Environmental changes in Sierra Nevada during the last 6 ky BP inferred from solifluction lobes and lake sediments

NASA Astrophysics Data System (ADS)

Oliva, M.; Gómez Ortiz, A.; Schulte, L.

2009-04-01

Holocene climate variability drove important landscape changes in Sierra Nevada, heightened due to the emplacement of Sierra Nevada at 37°N in southwestern Europe and, therefore, the different crossing influences in this region: geographical Europe/Africa), maritime (Atlantic/Mediterranean), climatic (subtropical high-pressure belt/ mid-latitude westerlies). Despite the existence of several kinds of sedimentary records in Sierra Nevada, only two of them can provide further information about Holocene landscape changes in this massif: solifluction lobes and mountain lakes. The numerous sedimentological changes inferred from terrestrial and aquatic records suggest the proximity of geomorphological processes in the massif of their climate boundaries and the small climate range necessary to carry environmental changes in the summits of the Sierra Nevada. Sierra Nevada holds the highest lakes in Europe, all of them related to a glacial origin. Four lakes were cored in Sierra Nevada, three of them southern exposed (Aguas Verdes, Rio Seco and Rio Seco lagoon) and only one with northern orientation (San Juan lagoon). Sedimentological properties of these cores assert evidences of different phases of coarse-grained inputs into the lakes, with low organic matter proportion and high mineral contents. These pulses correspond to geomorphic periods with enhanced slope instability, interfingered in phases with lower sediment transfer onto the lakes. These relative stable periods show a fine-grained texture with less mineral fraction and increases in the organic composition of the sediments. The similar evolution of the C/N ratio and Corg contents reflects the low productivity of these oligotrophic lakes and the terrestrial origin of the organic matter present in their sediments; both proxies also confirm a general pattern characterized in Sierra Nevada by an arid trend since the HWP, when the headwaters of the highest catchments stored a denser vegetation cover. We report an

Investigations into early rift development and geothermal resources in the Pyramid Lake fault zone, Western Nevada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eisses, A.; Kell, A.; Kent, G.

A. K. Eisses, A. M. Kell, G. Kent, N. W. Driscoll, R. E. Karlin, R. L. Baskin, J. N. Louie, S. Pullammanappallil, 2010, Investigations into early rift development and geothermal resources in the Pyramid Lake fault zone, Western Nevada: Abstract T33C-2278 presented at 2010 Fall Meeting, AGU, San Francisco, Calif., 13-17 Dec.

A Method for Snow Reanalysis: The Sierra Nevada (USA) Example

NASA Technical Reports Server (NTRS)

Girotto, Manuela; Margulis, Steven; Cortes, Gonzalo; Durand, Michael

2017-01-01

This work presents a state-of-the art methodology for constructing snow water equivalent (SWE) reanalysis. The method is comprised of two main components: (1) a coupled land surface model and snow depletion curve model, which is used to generate an ensemble of predictions of SWE and snow cover area for a given set of (uncertain) inputs, and (2) a reanalysis step, which updates estimation variables to be consistent with the satellite observed depletion of the fractional snow cover time series. This method was applied over the Sierra Nevada (USA) based on the assimilation of remotely sensed fractional snow covered area data from the Landsat 5-8 record (1985-2016). The verified dataset (based on a comparison with over 9000 station years of in situ data) exhibited mean and root-mean-square errors less than 3 and 13 cm, respectively, and correlation greater than 0.95 compared with in situ SWE observations. The method (fully Bayesian), resolution (daily, 90-meter), temporal extent (31 years), and accuracy provide a unique dataset for investigating snow processes. This presentation illustrates how the reanalysis dataset was used to provide a basic accounting of the stored snowpack water in the Sierra Nevada over the last 31 years and ultimately improve real-time streamflow predictions.

Measurements of Ozone Precursors in the Lake Tahoe Basin, USA

NASA Astrophysics Data System (ADS)

Zielinska, B.; Bytnerowicz, A.; Gertler, A.; McDaniel, M.; Rayne, S.; Burley, J. D.

2014-12-01

Lake Tahoe, located at 6,225 ft. (1,897 m) in the Sierra Nevada mountain range, is the largest alpine lake in North America. Known for the clarity of its water and the panorama of surrounding mountains on all sides, Lake Tahoe is a prime tourist attraction in the California - Nevada area. However, the Lake Tahoe Basin is facing significant environmental pollution problems, including declining water clarity and air quality issues. During the period of July 21 - 26, 2012, we conducted a field study in the Basin designed to characterize the precursors and pathways of secondary pollutant formation, including ozone and secondary organic aerosol (SOA). Four sites were selected; two were located at high elevations (one each on the western and eastern sides of the Basin) and two were positioned near the Lake level. Ozone and NO/NO2 concentrations were continuously measured. With a resolution of several hours over a 6-day sampling period canister samples were collected for detailed speciation of volatile organic compounds (VOC), 2,4-dinitrophenylhydrazine (DNPH) impregnated Sep-Pak cartridges for analysis of carbonyl compounds, PM2.5 Teflon and quartz filter samples for determination of mass, organic and elemental carbon (OC/EC) concentrations and speciation of organic compounds. Whereas the concentrations of lower molecular weight (mw) C2 - C3 hydrocarbons were generally the highest at all sampling sites, ranging from 25 to 76% of the total measured VOC (over 70 species from C2 to C10), the concentrations of biogenic hydrocarbons, isoprene and α-pinene were significant, ranging from 1.4 to 26% and 1.5 to 30%, respectively, of the total VOC. For comparison, the sum of benzene, toluene, ethylbenzene and xylenes (BTEX) constituted from 2.5 to 37% of the total VOC. All four sites showed maximum ozone concentrations in the range of 60 ppb. However, the lower sites show a pronounced diurnal pattern (i.e. maximum concentrations during the daytime hours, 0900 to 1700, with

Continuous lake-sediment records of glaciation in the Sierra Nevada between 52,600 and 12,500 14C yr B.P.

USGS Publications Warehouse

Benson, L.V.; May, Howard M.; Antweiler, Ronald C.; Brinton, T.I.; Kashgarian, Michaele; Smoot, J.P.; Lund, S.P.

1998-01-01

The chemistry of the carbonate-free clay-size fraction of Owens Lake sediments supports the use of total organic carbon and magnetic susceptibility as indicators of stadial-interstadial oscillations. Owens Lake records of total organic carbon, magnetic susceptibility, and chemical composition of the carbonate-free, clay-size fraction indicate that Tioga glaciation began ~24,500 and ended by ~13,600 14C yr B.P. Many of the components of glacial rock flour (e.g., TiO2, MnO, BaO) found in Owens Lake sediments achieved maximum values during the Tioga glaciation when valley glaciers reached their greatest extent. Total organic carbon and SiO2 (amorphous) concentrations reached minimum values during Tioga glaciation, resulting from decreases in productivity that accompanied the introduction of rock flour into the surface waters of Owens Lake. At least 20 stadial-interstadial oscillations occurred in the Sierra Nevada between 52,600 and 14,000 14C yr B.P. Total organic carbon data from a Pyramid Lake sediment core also indicate oscillations in glacier activity between >39,500 and ~13,600 14C yr B.P. Alpine glacier oscillations occurred on a frequency of ???1900 yr in both basins, suggesting that millennial-scale oscillations occurred in California and Nevada during most of the past 52,600 yr.

Reservoir-induced deformation and continental rheology in vicinity of Lake Mead, Nevada

NASA Astrophysics Data System (ADS)

Kaufmann, Georg; Amelung, Falk

2000-07-01

Lake Mead is a large reservoir in Nevada, formed by the construction of the 221-m-high Hoover Dam in the Black Canyon of the Colorado River. The lake encompasses an area of 635 km2, and the total volume of the reservoir is 35.5 km3. Filling started in February 1935. On the basis of a first-order leveling in 1935, several levelings were carried out to measure the deformation induced by the load of the reservoir. Subsidence in the central parts of the lake relative to the first leveling was around 120 mm (1941), 218 mm (1950), and 200 mm (1963). The subsidence pattern clearly shows relaxation of the underlying basement due to the water load of the lake, which ceased after 1950. Modeling of the relaxation process by means of layered, viscoelastic, compressible flat Earth models with a detailed representation of the spatial and temporal distribution of the water load shows that the thickness of the elastic crust underneath Lake Mead is 30±3 km. The data are also consistent with a 10-km-thick elastic upper crust and a 20-km-thick viscoelastic lower crust, with 1020 Pa s as a lower bound for its viscosity. The subcrust has an average viscosity of 1018±0.2 Pa s, a surprisingly low value. The leveling data constrain the viscosity profile down to ˜200 km depth.

DISTRIBUTIONS OF LAKE FISHES OF THE NORTHEAST USA--III. SALMONIDAE AND ASSOCIATED COLDWATER SPECIES

EPA Science Inventory

We present distributional maps and discuss native status for fish species characteristic of coldwater lakes, sampled from 203 randomly selected lakes in the northeastern USA (New England, New York, New Jersey). Eleven coldwater fish species from four families (Salmonidae, Osmeri...

Distribution and Climatic Relationships of the American Pika (Ochotona princeps) in the Sierra Nevada and Western Great Basin, U.S.A.; Periglacial Landforms as Refugia in Warming Climates

Treesearch

Constance I. Millar; Robert D. Westfall

2010-01-01

We used a rapid assessment to survey American pika (Ochotona princeps) populations and documented 420 pika site occurrences in southwestern U.S.A. These included 329 sites from the Sierra Nevada (SN), California; 67 from six southwestern Great Basin (swGB) ranges, California and Nevada; 16 from three central Great Basin ranges, Nevada; and 8 from...

Swath bathymetric survey of Englebright Lake, Yuba-Nevada Counties, California

USGS Publications Warehouse

Childs, Jonathan R.; Stevenson, Andrew J.

2006-01-01

In March, 2004, the USGS conducted a swath bathymetric survey of Englebright Lake, a 9-mile long reservoir located in the Sierra Nevada foothills of northern California on the Yuba River. This survey was follow-on to an earlier bathymetric survey and sediment thickness analysis done by the USGS in 2001 (Childs and others, 2003). The primary purpose of these studies is to assess the quantity and nature of the sediment that has accumulated since the dam was completed in 1940. The specific purpose of the swath bathymetry was to map in high detail the prograding delta that is being formed as the lake fills in with sediment. In the event of another large flood such as occurred on January 1, 1997, the survey could be repeated to determine the effect of such an event on the sediment volume and distribution. This study was conducted under the auspices of the Upper Yuba River Studies Program (UYRSP) . The UYRSP is funded by the CALFED Bay-Delta Program, whose mission is to "develop and implement a long-term comprehensive plan that will restore ecological health and improve water management for beneficial uses of the San Francisco Bay-Delta System".

Microbial ecology of soda lakes: investigating sulfur and nitrogen cycling at Mono Lake, CA, USA

NASA Astrophysics Data System (ADS)

Fairbanks, D.; Phillips, A. A.; Wells, M.; Bao, R.; Fullerton, K. M.; Stamps, B. W.; Speth, D. R.; Johnson, H.; Sessions, A. L.

2017-12-01

Soda lakes represent unique ecosystems characterized by extremes of pH, salinity and distinct geochemical cycling. Despite these extreme conditions, soda lakes are important repositories of biological adaptation and have a highly functional microbial system. We investigated the biogeochemical cycling of sulfur and nitrogen compounds in Mono Lake, California, located east of the Sierra Nevada mountains. Mono lake is characterized by hyperalkaline, hypersaline and high sulfate concentrations and can enter prolonged periods of meromixis due to freshwater inflow. Typically, the microbial sulfur cycle is highly active in soda lakes with both oxidation and reduction of sulfur compounds. However, the biological sulfur cycle is connected to many other main elemental cycles such as carbon, nitrogen and metals. Here we investigated the interaction between sulfur and nitrogen cycling in Mono lake using a combination of molecular, isotopic, and geochemical observations to explore the links between microbial phylogenetic composition and functionality. Metagenomic and 16S rRNA gene amplicon sequencing were determined at two locations and five depths in May 2017. 16S rRNA gene amplicon sequencing analysis revealed organisms capable of both sulfur and nitrogen cycling. The relative abundance and distribution of functional genes (dsrA, soxAB, nifH, etc) were also determined. These genetic markers indicate the potential in situ relevance of specific carbon, nitrogen, and sulfur pathways in the water column prior to the transition to meromictic stratification. However, genes for sulfide oxidation, denitrification, and ammonification were present. Genome binning guided by the most abundant dsrA sequences, GC content, and abundance with depth identified a Thioalkalivibrio paradoxus bin containing genes capable of sulfur oxidation, denitrification, and nitrate reduction. The presence of a large number of sulfur and nitrogen cycling genes associated with Thioalkalivibrio paradoxus

Climate, rain shadow, and human-use influences on fire regimes in the eastern Sierra Nevada, California, USA

Treesearch

M.P. North; K.M. van de Water; S.L. Stephens; B.M. Collins

2009-01-01

There have been few fire history studies of eastern Sierra Nevada forests in California, USA, where a steep elevation gradient, rain shadow conditions, and forest stand isolation may produce different fire regimes than those found on the range’s western slope. We investigated historic fire regimes and potential climate influences on four forest types ranging in...

Biological control reduces growth, and alters water relations of the saltcedar tree (Tamarix spp.) in western Nevada, USA

Treesearch

R.R. Pattison; C.M. D' Antonio; T.L. Dudley

2011-01-01

We monitored the impacts of a biological control agent, the saltcedar leaf beetle (Diorhabda carinulata), on the saltcedar tree (Tamarix spp.) at two sites (Humboldt and Walker rivers) in Nevada, USA. At the Humboldt site trees that had experienced three to four defoliation events had more negative water potentials and lower...

Fish mercury distribution in Massachusetts, USA lakes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rose, J.; Hutcheson, M.S.; West, C.R.

1999-07-01

The sediment, water, and three species of fish from 24 of Massachusetts' (relatively) least-impacted water bodies were sampled to determine the patterns of variation in edible tissue mercury concentrations and the relationships of these patterns to characteristics of the water, sediment, and water bodies (lake, wetland, and watershed areas). Sampling was apportioned among three different ecological subregions and among lakes of differing trophic status. The authors sought to partition the variance to discover if these broadly defined concepts are suitable predictors of mercury levels in fish. Average muscle mercury concentrations were 0.15 mg/kg wet weight in the bottom-feeding brown bullheadsmore » (Ameriurus nebulosus); 0.31 mg/kg in the omnivorous yellow perch (Perca flavescens); and 0.39 mg/kg in the predaceous largemouth bass (Micropterus salmoides). Statistically significant differences in fish mercury concentrations between ecological subregions in Massachusetts, USA, existed only in yellow perch. The productivity level of the lakes (as deduced from Carlson's Trophic Status Index) was not a strong predictor of tissue mercury concentrations in any species. pH was a highly (inversely) correlated environmental variable with yellow perch and brown bullhead tissue mercury. Largemouth bass tissue mercury concentrations were most highly correlated with the weight of the fish (+), lake size (+), and source area sizes (+). Properties of individual lakes appear more important for determining fish tissue mercury concentrations than do small-scale ecoregional differences. Species that show major mercury variation with size or trophic level may not be good choices for use in evaluating the importance of environmental variables.« less

Continuous Lake-Sediment Records of Glaciation in the Sierra Nevada between 52,600 and 12,500 14C yr B.P

NASA Astrophysics Data System (ADS)

Benson, Larry V.; May, Howard M.; Antweiler, Ronald C.; Brinton, Terry I.; Kashgarian, Michaele; Smoot, Joseph P.; Lund, Steve P.

1998-09-01

The chemistry of the carbonate-free clay-size fraction of Owens Lake sediments supports the use of total organic carbon and magnetic susceptibility as indicators of stadial-interstadial oscillations. Owens Lake records of total organic carbon, magnetic susceptibility, and chemical composition of the carbonate-free, clay-size fraction indicate that Tioga glaciation began ˜24,500 and ended by ˜13,600 14C yr B.P. Many of the components of glacial rock flour (e.g., TiO 2, MnO, BaO) found in Owens Lake sediments achieved maximum values during the Tioga glaciation when valley glaciers reached their greatest extent. Total organic carbon and SiO 2(amorphous) concentrations reached minimum values during Tioga glaciation, resulting from decreases in productivity that accompanied the introduction of rock flour into the surface waters of Owens Lake. At least 20 stadial-interstadial oscillations occurred in the Sierra Nevada between 52,600 and 14,000 14C yr B.P. Total organic carbon data from a Pyramid Lake sediment core also indicate oscillations in glacier activity between >39,500 and ˜13,600 14C yr B.P. Alpine glacier oscillations occurred on a frequency of ≤1900 yr in both basins, suggesting that millennial-scale oscillations occurred in California and Nevada during most of the past 52,600 yr.

Annually resolved late Holocene paleohydrology of the southern Sierra Nevada and Tulare Lake, California

NASA Astrophysics Data System (ADS)

Adams, Kenneth D.; Negrini, Robert M.; Cook, Edward R.; Rajagopal, Seshadri

2015-12-01

Here we present 2000 year long, annually resolved records of streamflow for the Kings, Kaweah, Tule, and Kern Rivers in the southwestern Sierra Nevada of California and consequent lake-level fluctuations at Tulare Lake in the southern San Joaquin Valley. The integrated approach of using moisture-sensitive tree ring records from the Living Blended Drought Atlas to reconstruct annual discharge and then routing this discharge to an annual Tulare Lake water balance model highlights the differences between these two types of paleoclimate records, even when subject to the same forcing factors. The reconstructed streamflow in the southern Sierra responded to yearly changes in precipitation and expressed a strong periodicity in the 2-8 year range over most of the reconstruction. The storage capacity of Tulare Lake caused it to fluctuate more slowly, masking the 2-8 year streamflow periodicity and instead expressing a strong periodicity in the 32-64 year range over much of the record. Although there have been longer droughts, the 2015 water year represents the driest in the last 2015 years and the 2012-2015 drought represents the driest 4 year period in the record. Under natural conditions, simulated Tulare Lake levels would now be at about 60 m, which is not as low as what occurred multiple times over the last 2000 years. This long-term perspective of fluctuations in climate and water supply suggests that different drought scenarios that vary in terms of severity and duration can produce similar lake-level responses in closed lake basins.

Atmospheric dry deposition on pines in the Eastern Brook Lake Watershed, Sierra Nevada, California

NASA Astrophysics Data System (ADS)

Bytnerowicz, Andrzej; Dawson, P. J.; Morrison, C. L.; Poe, M. P.

Atmospheric dry deposition to branches of Pinus contorta and P. albicaulis was measured during summer 1987 in a sub-alpine zone at Eastern Brook Lake Watershed (EBLW), eastern Sierra Nevada, California. Results are presented as deposition fluxes of NO 3-, SO 42-, PO 43-, Cl -, F -, NH 4+, Ca 2+, Mg 2+, Na +, K +, Zn 2+, Fe 3+, Mn 2+, Pb 2+ and H +, and compared with other locations in California and elsewhere. Deposition fluxes of anions and cations to the pine branches were low, several times lower than the values determined near the Emerald Lake Watershed (ELW), another sub-alpine location in the western Sierra Nevada. The sums of deposition fluxes of the measured cations and anions to pine surfaces were similar, in contrast to the ELW location where the sums of cation fluxes were much higher than the sums of anion fluxes. A strong positive correlation between depositions of NO 3- and NH 4+, as well as SO 42- and Ca 2+, suggested that large portions of these ions might have originated from particulate NH 4NO 3 and CaSO 4 deposited on pine surfaces. An estimated total N dry deposition (surface deposition of NO 3- and NH 4+ and internal uptake of NO 2 and HNO 3) to the forested area of the EBLW was 29.54 eq ha -1 yr - (about 414 g H ha -1 yr -1).

Cretaceous plutonic rocks in the Donner Lake-Cisco Grove area, northern Sierra Nevada, California

USGS Publications Warehouse

Kulow, Matthew J.; Hanson, Richard E.; Girty, Gary H.; Girty, Melissa S.; Harwood, David S.

1998-01-01

The northernmost occurrences of extensive, glaciated exposures of the Sierra Nevada batholith occur in the Donner Lake-Cisco Grove area of the northern Sierra Nevada. The plutonic rocks in this area, which are termed here the Castle Valley plutonic assemblage, crop out over an area of 225 km2 and for the most part are shown as a single undifferentiated mass on previously published geological maps. In the present work, the plutonic assemblage is divided into eight separate intrusive units or lithodemes, two of which each consist of two separate plutons. Compositions are dominantly granodiorite and tonalite, but diorite and granite form small plutons in places. Spectacular examples of comb layering and orbicular texture occur in the diorites. U-Pb zircon ages have been obtained for all but one of the main units and range from ~120 to 114 Ma, indicating that the entire assemblage was emplaced in a narrow time frame in the Early Cretaceous. This is consistent with abundant field evidence that many of the individual phases were intruded penecontemporaneously. The timing of emplacement correlates with onset of major Cretaceous plutonism in the main part of the Sierra Nevada batholith farther south. The emplacement ages also are similar to isotopic ages for gold-quartz mineralization in the Sierran foothills west of the study area, suggesting a direct genetic relationship between the voluminous Early Cretaceous plutonism and hydrothermal gold mineralization.

Land use change and effects on water quality and ecosystem health in the Lake Tahoe basin, Nevada and California

USGS Publications Warehouse

Forney, William; Richards, Lora; Adams, Kenneth D.; Minor, Timothy B.; Rowe, Timothy G.; Smith, J. LaRue; Raumann, Christian G.

2001-01-01

Human activity in the Lake Tahoe Basin has increased substantially in the past four decades, causing significant impacts on the quality and clarity of the lake's famous deep, clear water. Protection of Lake Tahoe and the surrounding environment has become an important activity in recent years. A variety of agencies, including the Tahoe Regional Planning Agency, Tahoe Research Group of the University of California at Davis, Desert Research Institute of the University and Community College System of Nevada, U.S. Geological Survey (USGS), and a host of State (both Nevada and California) and local agencies have been monitoring and conducting research in the Basin in order to understand how the lake functions and to what extent humans have affected its landscape and ecosystem processes. In spite of all of these activities, there remains a lack of comprehensive land use change data and analysis for the Basin. A project is underway that unites the land cover mapping expertise of the USGS National Mapping Discipline with the hydrologic expertise of the Water Resources Discipline to assess the impacts of urban growth and land use change in the Lake Tahoe Basin. Three activities are planned over the next 3 years: (1) mapping the current and historic state of the land surface, (2) conducting analysis to document patterns, rates, and trends in urbanization, land use change, and ecosystem health, and (3) assessing the causes and consequences of land use change with regard to water quality and ecosystem health. We hypothesize that changes in the extent of urban growth and the corresponding increases in impervious surfaces and decreases in natural vegetation have resulted in severe impacts on ecosystem health and integrity, riparian zones and water quality over time. We are acting on multiple fronts to test this hypothesis through the quantification of landscape disturbances and impacts.

Sierra Nevada Mountain Range as seen from STS-58

NASA Image and Video Library

1994-10-20

STS058-72-004 (18 Oct-1 Nov 1993) --- The Sierra Nevada Mountain Range can be seen in this north-looking high oblique view taken in October, 1993, by the STS-58 crew. Visible in the view to the west of the Sierra Nevada are the San Joaquin and Sacramento Valleys of central California. The San Francisco/Oakland Bay Area can be seen to the west of the valley at the extreme left of the photograph. To the east or right of the Sierra Nevada, the basin and Range Region of central and northern Nevada is visible. Mono Lake, Lake Tahoe and Pyramid Lake are also visible in this scene. The long northwest/southeast trending Walker Lane Shear Zone, which lies just to the east (right) of the Sierra Nevada is also visible. Near the top of the view (near the horizon), the snow covered volcanic peak Mount Shasta can be seen. Over 645 kilometers (400 miles) long and from 65 to 130 kilometers (40 to 80 miles) wide, the Sierra Nevada have many peaks in excess of 3,300 meters (11,000 feet) above sea level. A titled fault block in structure (the largest in the United States) and shaped by glaciers during the last ice age over 12,000 years ago, the Sierra Nevada eastern front rises sharply from the Great Basin of Nevada, while its western slope descends gradually to the hills bordering the Central Valley of California. Snow-fed streams supply much of the irrigation water to the Central Valley and to western Nevada and also generate hydroelectricity. Recent above normal precipitation (snowfall) of the last two years has helped in alleviating the drought conditions that had prevailed throughout most of California in the mid and late 1980's and early 1990's.

Marine and land active-source seismic investigation of geothermal potential, tectonic structure, and earthquake hazards in Pyramid Lake, Nevada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eisses, A.; Kell, A.; Kent, G.

Amy Eisses, Annie M. Kell, Graham Kent, Neal W. Driscoll, Robert E. Karlin, Robert L. Baskin, John N. Louie, Kenneth D. Smith, Sathish Pullammanappallil, 2011, Marine and land active-source seismic investigation of geothermal potential, tectonic structure, and earthquake hazards in Pyramid Lake, Nevada: presented at American Geophysical Union Fall Meeting, San Francisco, Dec. 5-9, abstract NS14A-08.

Calibrating Late Quaternary terrestrial climate signals: radiometrically dated pollen evidence from the southern Sierra Nevada, USA

USGS Publications Warehouse

Litwin, Ronald J.; Smoot, Joseph P.; Durika, Nancy J.; Smith, George I.

1999-01-01

We constructed a radiometrically calibrated proxy record of Late Pleistocene and Holocene climate change exceeding 230,000 yr duration, using pollen profiles from two cores taken through age-equivalent dry lakes - one core having greater age control (via 230Th alpha mass-spectrometry) and the other having greater stratigraphic completeness. The better dated of these two serial pollen records (Searles Lake) served as a reference section for improving the effective radiometric age control in a nearby and more complete pollen record (Owens Lake) because they: (1) are situated ~90 km apart in the same drainage system (on, and immediately leeward of, the eastern flank of the Sierra Nevada), and (2) preserved strikingly similar pollen profiles and concordant sequences of sedimentological changes. Pollen assemblages from both lakes are well preserved and diverse, and document serial changes in Late Pleistocene and Holocene plant zone distribution and composition in the westernmost Great Basin; they consist of taxa now inhabiting montane forest, woodland, steppe, and desert-scrub environments. The studied core intervals are interpreted here to be the terrestrial equivalent of marine δ18O stages 1 through 9; these pollen profiles now appear to be among the best radiometrically dated Late Pleistocene records of terrestrial climate change known.

Marine and land active-source seismic imaging of mid-Miocene to Holocene-aged faulting near geothermal prospects at Pyramid Lake, Nevada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eisses, A.; Kell, A.; Kent, G.

Amy Eisses, Annie Kell, Graham Kent, Neal Driscoll, Robert Karlin, Rob Baskin, John Louie, and Satish Pullammanappallil, 2011, Marine and land active-source seismic imaging of mid-Miocene to Holocene-aged faulting near geothermal prospects at Pyramid Lake, Nevada: presented at Geothermal Resources Council Annual Meeting, San Diego, Oct. 23-26.

Using machine learning to predict snow water equivalent in the Sierra Nevada USA and Afghanistan

NASA Astrophysics Data System (ADS)

Bair, N.; Rittger, K.; Dozier, J.

2017-12-01

In many mountain regions, snowmelt provides most of the runoff. Ranges such as the Sierra Nevada USA benefit from hundreds of manual and automated snow measurement stations as well as basin-wide snow water equavalent (SWE) estimates from new platforms like the Airborne Snow Observatory. Thus, we have been able to use the Sierra Nevada as a testbed to validate an approach called SWE reconstruction, where the snowpack is built-up in reverse using downscaled energy balance forcings. Our past work has shown that SWE reconstruction produces some of the most accurate basin-wide SWE estimates, comparable in accuracy to a snow pillow/course interpolation, but requires no in situ measurements, which is its main advantage. The disadvantages are that reconstruction cannot be used for a forecast and is only valid during the ablation period. To address these shortcomings, we have used machine learning trained on reconstructed SWE in the Sierra Nevada and Afghanistan, where there are no accessible snowpack measurements. Predictors are physiographic and remotely-sensed variables, including brightness temperatures from a new enhanced resolution passive microwave dataset. Two machine learning techniques—bagged regression trees and feed-forward neural networks—were used. Results show little bias on average and < 100 mm RMSE. For both areas, daily SWE climatology and fractional snow-covered area were the most important predictors. As expected, the passive microwave brigthness temperatures showed some predictive power in Afghanistan, with its almost nonexistent tree cover, but no predictive power in the Sierra Nevada, with its extensive canopy-covered snowpack. In the Sierra, we also explored how our machine learning approach performed outside of the training period, i.e. the ablation period.

Sensitivity analysis of lake mass balance in discontinuous permafrost: the example of disappearing Twelvemile Lake, Yukon Flats, Alaska (USA)

USGS Publications Warehouse

Jepsen, S.M.; Voss, C.I.; Walvoord, Michelle Ann; Rose, J.R.; Minsley, B.J.; Smith, B.D.

2013-01-01

Many lakes in northern high latitudes have undergone substantial changes in surface area over the last four decades, possibly as a result of climate warming. In the discontinuous permafrost of Yukon Flats, interior Alaska (USA), these changes have been non-uniform across adjacent watersheds, suggesting local controls on lake water budgets. Mechanisms that could explain the decreasing mass of one lake in Yukon Flats since the early 1980s, Twelvemile Lake, are identified via a scoping analysis that considers plausible changes in snowmelt mass and infiltration, permafrost distribution, and climate warming. Because predicted changes in evaporation (2 cmyr-1) are inadequate to explain the observed 17.5 cmyr-1 reduction in mass balance, other mechanisms are required. The most important potential mechanisms are found to involve: (1) changes in shallow, lateral groundwater flow to the lake possibly facilitated by vertical freeze-thaw migration of the permafrost table in gravel; (2) increased loss of lake water as downward groundwater flow through an open talik to a permeable subpermafrost flowpath; and (3) reduced snow meltwater inputs due to decreased snowpack mass and increased infiltration of snowmelt into, and subsequent evaporation from, fine-grained sediment mantling the permafrost-free lake basin.

Surface motion of active rock glaciers in the Sierra Nevada, California, USA: inventory and a case study using InSAR

Treesearch

L. Liu; C.I. Millar; R.D. Westfall; H.A. Zebker

2013-01-01

Despite the abundance of rock glaciers in the Sierra Nevada of California, USA, few efforts have been made to measure their surface flow. Here we use the interferometric synthetic aperture radar (InSAR) technique to compile a~benchmark inventory describing the kinematic state of 59 active rock glaciers in this region. Statistically, these rock glaciers moved at...

Year-round presence of neonicotinoid insecticides in tributaries to the Great Lakes, USA

EPA Science Inventory

To better understand the transport of neonicotinoid insecticides to a sensitive freshwater ecosystem, monthly samples (October 2015-September 2016) were collected from 10 major tributaries to the Great Lakes, USA. For the monthly tributary samples, neonicotinoids were detected in...

Microbial diversity associated with the anaerobic sediments of a soda lake (Mono Lake, California, USA).

PubMed

Rojas, Patricia; Rodríguez, Nuria; de la Fuente, Vicenta; Sánchez-Mata, Daniel; Amils, Ricardo; Sanz, José L

2018-06-01

Soda lakes are inhabited by important haloalkaliphilic microbial communities that are well adapted to these extreme characteristics. The surface waters of the haloalkaline Mono Lake (California, USA) are alkaline but, in contrast to its bottom waters, do not present high salinity. We have studied the microbiota present in the shoreline sediments of Mono Lake using next-generation sequencing techniques. The statistical indexes showed that Bacteria had a higher richness, diversity, and evenness than Archaea. Seventeen phyla and 8 "candidate divisions" were identified among the Bacteria, with a predominance of the phyla Firmicutes, Proteobacteria, and Bacteroidetes. Among the Proteobacteria, there was a notable presence of Rhodoplanes and a high diversity of sulfate-reducing Deltaproteobacteria, in accordance with the high sulfate-reducing activity detected in soda lakes. Numerous families of bacterial fermenters were identified among the Firmicutes. The Bacteroides were represented by several environmental groups that have not yet been isolated. Since final organic matter in anaerobic environments with high sulfate contents is mineralized mainly by sulfate-reducing bacteria, very little methanogenic archaeal biodiversity was detected. Only 2 genera, Methanocalculus and Methanosarcina, were retrieved. The species similarities described indicate that a significant number of the operational taxonomic units identified may represent new species.

Calcite growth-rate inhibition by fulvic acids isolated from Big Soda Lake, Nevada, USA, The Suwannee River, Georgia, USA and by polycarboxylic acids

USGS Publications Warehouse

Reddy, Michael M.; Leenheer, Jerry

2011-01-01

Calcite crystallization rates are characterized using a constant solution composition at 25°C, pH=8.5, and calcite supersaturation (Ω) of 4.5 in the absence and presence of fulvic acids isolated from Big Soda Lake, Nevada (BSLFA), and a fulvic acid from the Suwannee River, Georgia (SRFA). Rates are also measured in the presence and absence of low-molar mass, aliphatic-alicyclic polycarboxylic acids (PCA). BSLFA inhibits calcite crystal-growth rates with increasing BSLFA concentration, suggesting that BSLFA adsorbs at growth sites on the calcite crystal surface. Calcite growth morphology in the presence of BSLFA differed from growth in its absence, supporting an adsorption mechanism of calcite-growth inhibition by BSLFA. Calcite growth-rate inhibition by BSLFA is consistent with a model indicating that polycarboxylic acid molecules present in BSLFA adsorb at growth sites on the calcite crystal surface. In contrast to published results for an unfractionated SRFA, there is dramatic calcite growth inhibition (at a concentration of 1 mg/L) by a SRFA fraction eluted by pH 5 solution from XAD-8 resin, indicating that calcite growth-rate inhibition is related to specific SRFA component fractions. A cyclic PCA, 1, 2, 3, 4, 5, 6-cyclohexane hexacarboxylic acid (CHXHCA) is a strong calcite growth-rate inhibitor at concentrations less than 0.1 mg/L. Two other cyclic PCAs, 1, 1 cyclopentanedicarboxylic acid (CPDCA) and 1, 1 cyclobutanedicarboxylic acid (CBDCA) with the carboxylic acid groups attached to the same ring carbon atom, have no effect on calcite growth rates up to concentrations of 10 mg/L. Organic matter ad-sorbed from the air onto the seed crystals has no effect on the measured calcite crystal-growth rates.

Response of Subalpine Conifers in the Sierra Nevada, California, U.S.A., to 20th-Century Warming and Decadal Climate Variability

Treesearch

Constance I. Millar; Robert D. Westfall; Diane L. Delany; John C. King; Lisa J. Graumlich

2004-01-01

Four independent studies of conifer growth between 1880 and 2002 in upper elevation forests of the central Sierra Nevada, California, U.S.A., showed correlated multidecadal and century-long responses associated with climate. Using tree-ring and ecological plot analysis, we studied annual branch growth of krummholz Pinus albicaulis; invasion by P....

Development of watershed models for emerald lake watershed in Sequoia National Park and for other lakes of the Sierra Nevada. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sorooshian, S.; Bales, R.C.; Gupta, V.K.

1992-02-01

In order to better understand the implications of acid deposition in watershed systems in the Sierra Nevada, the California Air Resources Board (CARB) initiated an intensive integrated watershed study at Emerald Lake in Sequoia National Park. The comprehensive nature of the data obtained from these studies provided an opportunity to develop a quantitative description of how watershed characteristics and inputs to the watershed influence within-watershed fluxes, chemical composition of streams and lakes, and, therefore, biotic processes. Two different but closely-related modeling approaches were followed. In the first, the emphasis was placed on the development of systems-theoretic models. In the secondmore » approach, development of a compartmental model was undertaken. The systems-theoretic effort results in simple time-series models that allow the consideration of the stochastic properties of model errors. The compartmental model (the University of Arizona Alpine Hydrochemical Model (AHM)) is a comprehensive and detailed description of the various interacting physical and chemical processes occurring on the watershed.« less

Late Holocene subalpine lake sediments record a multi-proxy shift to increased aridity at 3.65 kyr BP, following a millennial-scale neopluvial interval in the Lake Tahoe watershed and western Great Basin, USA

NASA Astrophysics Data System (ADS)

Noble, Paula; Zimmerman, Susan; Ball, Ian; Adams, Kenneth; Maloney, Jillian; Smith, Shane

2016-04-01

A mid Holocene dry period has been reported from lake records in the Great Basin and Sierra Nevada, yet the spatial and temporal extent of this interval is not well understood. We present evidence for a millennial-scale interval of high winter precipitation (neopluvial) at the end of the mid Holocene in the Lake Tahoe-Pyramid Lake watershed in the northern Sierra Nevada that reached its peak ˜3.7 kcal yr BP. A transect of 4 cores recovered from Fallen Leaf Lake in the Tahoe Basin were dated using AMS14C on plant macrofossils, and analyzed using scanning XRF, C and N elemental and stable isotope measurements, and diatoms as paleoclimate proxies. Fallen Leaf Lake is a deep glacially-derived lake situated in the Glen Alpine Valley at an elevation of 1942m, ˜45 m above the level of Lake Tahoe. In Fallen Leaf Lake, the end of the neopluvial is dated at 3.65 ± 0.09 kcal yr BP, and is the largest post-glacial signal in the cores. The neopluvial interval is interpreted to be a period of increased snowpack in the upper watershed, supported by depleted g δ13Corg (-27.5) values, negative baseline shifts in TOC and TN, lower C:N, and high abundances of Aulacoseira subarctica, a winter-early spring diatom. Collectively, these proxies indicate cooler temperatures, enhanced mixing, and/or shortened summer stratification resulting in increased algal productivity relative to terrestrial inputs. The neopluvial interval ends abruptly at 3.65 ka, with a change from mottled darker opaline clay to a homogeneous olive clay with decreased A. subarctica and opal, and followed by a 50% reduction in accumulation rates. After this transition δ13Corg becomes enriched by 2‰ and TOC, TN, and C:N all show the start of positive trends that continue through the Holocene. Pyramid Lake is an endorheic basin situated at the terminal end of the watershed, and inflow arrives from the Lake Tahoe basin via the Truckee River. At Pyramid Lake, existing ages on paleo-shorelines indicate a significant

New constraints on slip-rates, recurrence intervals, and strain partitioning beneath Pyramid Lake, Nevada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eisses, Amy

A high-resolution CHIRP seismic survey of Pyramid Lake, Nevada, located within the northern Walker Lane Deformation Belt, was conducted in summer 2010. Seismic CHIRP data with submeter vertical accuracy, together with piston and gravity cores, were used to calculate Holocene vertical slip rates, relative earthquake timing, and produce the first complete fault map beneath the lake. More than 500 line-kilometers of CHIRP data imaged complex fault patterns throughout the basin. Fault architecture beneath Pyramid Lake highlights a polarity flip, where down-to-the west patterns of sedimentation near the dextral Pyramid Lake fault to the south give way to down-to-the-east geometries tomore » the north within a mostly normal (i.e., Lake Range fault) and transtensional environment. The Lake Range fault predominantly controls extensional deformation within the northern two-thirds of the basin and exhibits varying degrees of asymmetric tilting and divergence due to along-strike segmentation. This observation is likely a combination of fault segments splaying onshore moving the focus of extension away from the lake coupled with some true along-strike differences in slip-rate. The combination of normal and oblique-slip faults in the northern basin gives Pyramid Lake its distinctive “fanning open to the north” tectonic geometry. The dense network of oblique-slip faults in the northwestern region of the lake, in contrast to the well-defined Lake Range fault, are short and discontinuous in nature, and possible represent a nascent shear zone. Preliminary vertical slip-rates measured across the Lake Range and other faults provide new estimates on the extension across the Pyramid Lake basin. A minimum vertical slip rate of ~1.0 mm/yr is estimated along the Lake Range fault, which yields a potential earthquake magnitude range between M6.4 and M7.0. A rapid influx of sediment was deposited shortly after the end of the Tioga glaciation somewhere between 12.5 ka to 9.5 ka and

Geologic investigation of Playa Lakes, Tonopah Test Range, Nevada : data report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rautman, Christopher Arthur

Subsurface geological investigations have been conducted at two large playa lakes at the Tonopah Test Range in central Nevada. These characterization activities were intended to provide basic stratigraphic-framework information regarding the lateral distribution of ''hard'' and ''soft'' sedimentary materials for use in defining suitable target regions for penetration testing. Both downhole geophysical measurements and macroscopic lithilogic descriptions were used as a surrogate for quantitative mechanical-strength properties, although some quantitative laboratory strength measurements were obtained as well. Both rotary (71) and core (19) holes on a systematic grid were drilled in the southern half of the Main Lake; drill hole spacingsmore » are 300 ft north-south and 500-ft east-west. The drilled region overlaps a previous cone-penetrometer survey that also addressed the distribution of hard and soft material. Holes were drilled to a depth of 40 ft and logged using both geologic examination and down-hole geophysical surveying. The data identify a large complex of very coarse-grained sediment (clasts up to 8 mm) with interbedded finer-grained sands, silts and clays, underlying a fairly uniform layer of silty clay 6 to 12 ft thick. Geophysical densities of the course-grained materials exceed 2.0 g/cm{sup 2}, and this petrophysical value appears to be a valid discriminator of hard vs. soft sediments in the subsurface. Thirty-four holes, including both core and rotary drilling, were drilled on a portion of the much larger Antelope Lake. A set of pre-drilling geophysical surveys, including time-domain electromagnetic methods, galvanic resistivity soundings, and terrain-conductivity surveying, was used to identify the gross distribution of conductive and resistive facies with respect to the present lake outline. Conductive areas were postulated to represent softer, clay-rich sediments with larger amounts of contained conductive ground water. Initial drilling

Water Budgets of the Walker River Basin and Walker Lake, California and Nevada

USGS Publications Warehouse

Lopes, Thomas J.; Allander, Kip K.

2009-01-01

The Walker River is the main source of inflow to Walker Lake, a closed-basin lake in west-central Nevada. The only outflow from Walker Lake is evaporation from the lake surface. Between 1882 and 2008, upstream agricultural diversions resulted in a lake-level decline of more than 150 feet and storage loss of 7,400,000 acre-feet. Evaporative concentration increased dissolved solids from 2,500 to 17,000 milligrams per liter. The increase in salinity threatens the survival of the Lahontan cutthroat trout, a native species listed as threatened under the Endangered Species Act. This report describes streamflow in the Walker River basin and an updated water budget of Walker Lake with emphasis on the lower Walker River basin downstream from Wabuska, Nevada. Water budgets are based on average annual flows for a 30-year period (1971-2000). Total surface-water inflow to the upper Walker River basin upstream from Wabuska was estimated to be 387,000 acre-feet per year (acre-ft/yr). About 223,000 acre-ft/yr (58 percent) is from the West Fork of the Walker River; 145,000 acre-ft/yr (37 percent) is from the East Fork of the Walker River; 17,000 acre-ft/yr (4 percent) is from the Sweetwater Range; and 2,000 acre-ft/yr (less than 1 percent) is from the Bodie Mountains, Pine Grove Hills, and western Wassuk Range. Outflow from the upper Walker River basin is 138,000 acre-ft/yr at Wabuska. About 249,000 acre-ft/yr (64 percent) of inflow is diverted for irrigation, transpired by riparian vegetation, evaporates from lakes and reservoirs, and recharges alluvial aquifers. Stream losses in Antelope, Smith, and Bridgeport Valleys are due to evaporation from reservoirs and agricultural diversions with negligible stream infiltration or riparian evapotranspiration. Diversion rates in Antelope and Smith Valleys were estimated to be 3.0 feet per year (ft/yr) in each valley. Irrigated fields receive an additional 0.8 ft of precipitation, groundwater pumpage, or both for a total applied-water rate

75 FR 57493 - Notice of Inventory Completion: Department of Anthropology & Ethnic Studies, University of Nevada...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-21

..., Nevada; Shoshone-Paiute Tribes of the Duck Valley Reservation, Nevada; South Fork Band (Constituent Band... of Idaho; Shoshone-Paiute Tribes of the Duck Valley Reservation, Nevada; South Fork Band (Constituent... Idaho; Shoshone-Paiute Tribes of the Duck Valley Reservation, Nevada; South Fork Band; Summit Lake...

Commodity Flow Study - Clark County, Nevada, USA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conway, S.Ph.D.; Navis, I.

2008-07-01

The United States Department of Energy has designated Clark County, Nevada as an 'Affected Unit of Local Government' due to the potential for impacts by activities associated with the Yucca Mountain High Level Nuclear Waste Repository project. Urban Transit, LLC has led a project team of transportation including experts from the University of Nevada Las Vegas Transportation Research Center to conduct a hazardous materials community flow study along Clark County's rail and truck corridors. In addition, a critical infrastructure analysis has also been carried out in order to assess the potential impacts of transportation within Clark County of high levelmore » nuclear waste and spent nuclear fuel to a proposed repository 90 miles away in an adjacent county on the critical infrastructure in Clark County. These studies were designed to obtain information relating to the transportation, identification and routing of hazardous materials through Clark County. Coordinating with the United States Department of Energy, the U.S. Department of Agriculture, the U. S. Federal Highway Administration, the Nevada Department of Transportation, and various other stakeholders, these studies and future research will examine the risk factors along the entire transportation corridor within Clark County and provide a context for understanding the additional vulnerability associated with shipping spent fuel through Clark County. (authors)« less

Hydrogeologic influence on changes in snowmelt runoff with climate warming: Numerical experiments on a mid-elevation catchment in the Sierra Nevada, USA

Treesearch

S.M. Jepsen; T.C. Harmon; M.W. Meadows; C.T. Hunsaker

2016-01-01

The role of hydrogeology in mediating long-term changes in mountain streamflow, resulting from reduced snowfall in a potentially warmer climate, is currently not well understood. We explore this by simulating changes in stream discharge and evapotranspiration from a mid-elevation, 1-km2 catchment in the southern Sierra Nevada of California (USA)...

ORGANIC POLLUTANT DEPOSITION TO THE SIERRA NEVADA (CALIFORNIA, USA) SNOWPACK AND ASSOCIATED LAKE AND STREAM ECOSYSTEM

EPA Science Inventory

High elevation ecosystems in the western USA and Canada are receiving deposition of persistent organic pollutants (POPs) that presumably originate in the USA as well as outside its borders. In April 1992 we obtained paired snowpack samples from each of two watersheds located in t...

The tufas of Pyramid Lake, Nevada

USGS Publications Warehouse

Benson, Larry V.

2004-01-01

Pyramid Lake is the site of some of the Earth's most spectacular tufa deposits. The Tufas are composed of calcium carbonate (CaCO3). The large tufa mounds, reef- and sheet-like tufas formed within Pyramid Lake, between 26,000 and 13,000 years (yr) ago, when the lake was part of pluvial Lake Lahontan. The mounds are composed of large interlocking spheres that contain multiple generations of a crystalline (thinolite) variety of tufa. Over time many of the mounds have fallen apart, exposing an internal network of tubes. The tubular structures are thought to have been created when springs discharged from the bottom of Pyramid Lake, supplying calcium that combined with carbonate dissolved in lake water to form the mounds. The reef- and sheet-like deposits contain pillow and pendant forms made up of a branching variety of tufa that often grades into dense layers or nodules. Dense layers of tufa also coat cobbles and boulders that were deposited in near-shore shallow-water areas. The thickest tufa deposits formed at lake-bottom sites of ground-water discharge and at overflow elevations1 where the lake was held at near-constant levels for long periods of time.

Fish community comparisons along environmental gradients in lakes of France and north-east USA

EPA Science Inventory

To assess whether eight traits of fish communities (species richness, three reproductive traits and four trophic traits) respond similarly to environmental gradients, and consequently display convergence between the lakes of France and north-east USA (NEUSA). Location 75 Frenc...

The aquatic optics of Lake Tahoe, California-Nevada

NASA Astrophysics Data System (ADS)

Swift, Theodore John

The causes of visual clarity decline and variability in Lake Tahoe, USA, were investigated within the framework of hydrologic optics theory. Ultra-oligotrophic subalpine (1898 m elevation) Lake Tahoe is among the world's clearest, deepest (499 m) and largest (500 km2), representing a unique environmental and economic resource. University of California Davis has documented a ˜0.3 m y-1 trend of decreasing Secchi depth, with ˜3 m interannual variations. Previous work strongly suggested two seasonal modes due to independent processes: A June minimum is due primarily to tributary sediment discharge during snowmelt. A December minimum is due to the deepening mixed layer bringing up phytoplankton and other particles that form a deep particle maximum (DCM) well below the summer mixed layer and Secchi depth stratum. SEM and elemental analysis confirmed as much as 60 percent of near-surface suspended particles were of terrestrial inorganic origin in summer, with inorganic particles minimal (˜20 percent) in winter. Chromophoric dissolved organic matter (CDOM) light absorption in Tahoe is extremely low, comparable to pelagic marine waters, and plays a minor role in clarity loss in Tahoe. However, CDOM reduces ultraviolet light penetration. Mean absorption is 0.040 +/- 0.003 m-1 at 400 nm with 0.023 +/- 0.004 nm-1 exponential slope. The CDOM appears to be autochthonous (phytoplankton), rather than allocthonous (terrestrial humic substances). Chlorophyll-specific particulate absorption is similar to that found for temperate oceans, implying that ocean color models can be successfully applied to Lake Tahoe. Chlorophyll-specific diffuse attenuation along with increased scattering by sediments has caused an upward shift of the DCM from 60--90 m (early 1970s) to 40--70 m recently. Increased attenuation will reduce benthic relative to pelagic primary production. Since measurements in 1971, the lake's color has shifted slightly from blue towards green, though more seasonal

Preliminary 3d depth migration of a network of 2d seismic lines for fault imaging at a Pyramid Lake, Nevada geothermal prospect

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frary, R.; Louie, J.; Pullammanappallil, S.

Roxanna Frary, John N. Louie, Sathish Pullammanappallil, Amy Eisses, 2011, Preliminary 3d depth migration of a network of 2d seismic lines for fault imaging at a Pyramid Lake, Nevada geothermal prospect: presented at American Geophysical Union Fall Meeting, San Francisco, Dec. 5-9, abstract T13G-07.

The status of childhood lead poisoning and prevention in Nevada, USA.

PubMed

Rothweiler, Anne M; Cabb, Elena E; Gerstenberger, Shawn L

2007-03-30

One of the first steps in addressing the problem of childhood lead poisoning is to identify the possible sources of exposure in specific communities and target high-risk populations with appropriate interventions. Due to several factors, such as lack of funding and lack of blood lead reporting, little information exists regarding the occurrence of childhood lead poisoning and the prevalence of potential exposure sources in the state of Nevada. Following the recent establishment of a Nevada-based Lead Poisoning Program, we compiled the most current information available on Nevadans, and use this knowledge to suggest future research objectives and outreach activities for the state. Accordingly, we identify the characteristics of the vulnerable Nevada populations, explore possible sources of lead exposure unique to Nevada, and summarize the existing data on childhood lead poisoning. Emerging data indicates that Nevada is an area of rapid population growth, characterized by increasing immigration from Latin America, increasing numbers of children from low-income families with no health insurance. Also, childhood lead poisoning may arise from exposure to non-paint sources of lead. After presenting the Nevada statistics, we propose and recommend a set of research and outreach strategies that best suit the needs of Nevada residents.

PREDICTION OF CONTAMINATED SEDIMENT TRANSPORT IN THE MAURICE RIVER-UNION LAKE, NEW JERSEY, USA

EPA Science Inventory

This paper describes a sediment and contaminant transport model and its application to the Maurice River-Union Lake system in southern New Jersey, USA for the purpose of characterizing and forecasting sediment and arsenic distributions before and after proposed dredging activitie...

Sediment-source data for four basins tributary to Lake Tahoe, California and Nevada; August 1983-June 1988

USGS Publications Warehouse

Hill, B.R.; Hill, J.R.; Nolan, K.M.

1990-01-01

Data were collected during a 5-year study of sediment sources in four drainage basins tributary to Lake Tahoe, California-Nevada. The study areas include the Blackwood Creek, General Creek, Edgewood Creek, and Logan House Creek basins. Data include changes in bank and bed positions at channel cross sections; results of stream-channel inventories; analyses of bank and bed material samples; tabulations of bed-material pebble counts; measured rates of hillslope erosion; dimensions of gullies; suspended-sediment data collected during synoptic snowmelt sampling; and physiographic data for the four study basins. (USGS)

PREDICTION OF CONTAMINATED SEDIMENT TRANSPORT IN THE MAURICE RIVER-UNION LAKE, NEW JERSEY, USA

EPA Science Inventory

A sediment and contaminant transport model and its application to the Maurice River-Union Lake system in southern New Jersey, USA is described. The application is meant to characterize and forecast sediment and arsenic (As) distributions before and after proposed dredging activit...

Gaseous Oxidized Mercury Flux from Substrates Associated with Industrial Scale Gold Mining in Nevada, USA

NASA Astrophysics Data System (ADS)

Miller, M. B.

2015-12-01

Gaseous elemental and oxidized mercury (Hg) fluxes were measured in a laboratory setting from substrate materials derived from industrial-scale open pit gold mining operations in Nevada, USA. Mercury is present in these substrates at a range of concentrations (10 - 40000 ng g-1), predominantly of local geogenic origin in association with the mineralized gold ores, but altered and redistributed to a varying degree by subsequent ore extraction and processing operations, including deposition of Hg recently emitted to the atmosphere from large point sources on the mines. Waste rock, heap leach, and tailings material usually comprise the most extensive and Hg emission relevant substrate surfaces. All three of these material types were collected from active Nevada mine sites in 2010 for previous research, and have since been stored undisturbed at the University of Nevada, Reno. Gaseous elemental Hg (GEM) flux was previously measured from these materials under a variety of conditions, and was re-measured in this study, using Teflon® flux chambers and Tekran® 2537A automated ambient air analyzers. GEM flux from dry undisturbed materials was comparable between the two measurement periods. Gaseous oxidized Hg (GOM) flux from these materials was quantified using an active filter sampling method that consisted of polysulfone cation-exchange membranes deployed in conjunction with the GEM flux apparatus. Initial measurements conducted within greenhouse laboratory space indicate that in dry conditions GOM is deposited to relatively low Hg cap and leach materials, but may be emitted from the much higher Hg concentration tailings material.

A multiproxy environmental investigation of Holocene wood from a submerged conifer forest in Lake Huron, USA

Treesearch

R. Douglas Hunter; Irina P. Panyushkina; Steven W. Leavitt; Alex C. Wiedenhoeft; John Zawiskie

2006-01-01

Remains of a Holocene drowned forest in southern Lake Huron discovered in 12.5 m of water (164 m above sea level), 4.5 km east of Lexington, Michigan USA (Sanilac site), provided wood to investigate environment and lake history using several proxies. Macrofossil evidence indicates a forest comprised primarily of conifers equivalent to the modern “rich conifer swamp”...

Isoscapes of the Sierra Nevada, California: Inferences from Landscape Patterns of Carbon, Nitrogen and Hydrogen in Lakes and Their Watersheds

NASA Astrophysics Data System (ADS)

Sickman, J. O.; Sadro, S.; Lucero, D. M.

2016-12-01

Montane aquatic ecosystems integrate conditions within their catchments and act as sentinels for environmental change. Variations in elevation, atmospheric deposition, and bedrock chemistry produce complex environmental gradients that influence the flow of materials and energy between lakes and their watersheds. We investigated the landscape-level variations in stable isotopes (Isoscapes) of C, N and H in foodwebs of 12 Sierra Nevada lakes and watersheds spanning an elevation range of 1500 to 3500 m a.s.l. Collections included terrestrial plants, soils and insects and the entire aquatic food chain from dissolved organic matter (DOM) through plankton, benthic invertebrates and fish. Our major objective was to understand how environmental gradients such as temperature and precipitation (distance-for-time proxies for climate change) effect foodweb structure and reciprocal subsidies of C and energy between lakes and their watersheds. Possibly related to its role as a limiting nutrient for aquatic and terrestrial ecosystems, we observed no consistent pattern for δ15N across any environmental gradient. In contrast, there was a strong pattern of enrichment in 13C with increasing elevation (slope = +3.4 permil per km). Similarly, δ2H of snowfall and foodweb components showed a depletion of 2H with elevation (slope = -17 permil per km for foodwebs and -20 permil per km for water) suggesting strong influence of snowmelt on aquatic ecosystem function. We will further explore these isotope patterns and draw inferences on how changes in montane climate, including trends toward earlier snowmelt and lower snowfall, will impact aquatic ecosystems of the Sierra Nevada.

Temporal and spatial trends in nutrient and sediment loading to Lake Tahoe, California-Nevada, USA

USGS Publications Warehouse

Coats, Robert; Lewis, Jack; Alvarez, Nancy L.; Arneson, Patricia

2016-01-01

Since 1980, the Lake Tahoe Interagency Monitoring Program (LTIMP) has provided stream-discharge and water quality data—nitrogen (N), phosphorus (P), and suspended sediment—at more than 20 stations in Lake Tahoe Basin streams. To characterize the temporal and spatial patterns in nutrient and sediment loading to the lake, and improve the usefulness of the program and the existing database, we have (1) identified and corrected for sources of bias in the water quality database; (2) generated synthetic datasets for sediments and nutrients, and resampled to compare the accuracy and precision of different load calculation models; (3) using the best models, recalculated total annual loads over the period of record; (4) regressed total loads against total annual and annual maximum daily discharge, and tested for time trends in the residuals; (5) compared loads for different forms of N and P; and (6) tested constituent loads against land use-land cover (LULC) variables using multiple regression. The results show (1) N and P loads are dominated by organic N and particulate P; (2) there are significant long-term downward trends in some constituent loads of some streams; and (3) anthropogenic impervious surface is the most important LULC variable influencing water quality in basin streams. Many of our recommendations for changes in water quality monitoring and load calculation methods have been adopted by the LTIMP.

Use of Weighted Regressions on Time, Discharge, and Season to Assess Effectiveness of Agricultural and Environmental Best Management Practices in California and Nevada, USA

NASA Astrophysics Data System (ADS)

Domagalski, J. L.; Schlegel, B.; Hutchins, J.

2014-12-01

Long-term data sets on stream-water quality and discharge can be used to assess whether best management practices (BMPs) are restoring beneficial uses of impaired water as required under the Clean Water Act. In this study, we evaluated a greater than 20-year record of water quality from selected streams in the Central Valley (CV) of California and Lake Tahoe (California and Nevada, USA). The CV contains a mix of agricultural and urbanized land, while the Lake Tahoe area is mostly forested, with seasonal residents and tourism. Because nutrients and fine sediments cause a reduction in water clarity that impair Lake Tahoe, BMPs were implemented in the early 1990's, to reduce nitrogen and phosphorus loads. The CV does not have a current nutrient management plan, but numerous BMPs exist to reduce pesticide loads, and it was hypothesized that these programs could also reduce nutrient levels. In the CV and Lake Tahoe areas, nutrient concentrations, loads, and trends were estimated by using the recently developed Weighted Regressions on Time, Discharge, and Season (WRTDS) model. Sufficient data were available to compare trends during a voluntary and enforcement period for seven CV sites within the lower Sacramento and San Joaquin Basins. For six of the seven sites, flow-normalized mean annual concentrations of total phosphorus and nitrate decreased at a faster rate during the enforcement period than during the earlier voluntary period. Concentration changes during similar years and ranges of flow conditions suggest that BMPs designed for pesticides also reduced nutrient loads in the CV. A trend analysis using WRTDS was completed for six streams that enter Lake Tahoe during the late 1980's through 2008. The results of the model confirm that nutrient loading is influenced strongly by season, such as by spring runoff from snowmelt. The highest nutrient concentrations in the late 1980's and early 1990's correlate with high flows, followed by statistically significant decreases

Preliminary Surficial Geologic Map of the Mesquite Lake 30' X 60' Quadrangle, California and Nevada

USGS Publications Warehouse

Schmidt, Kevin M.; McMackin, Matthew

2006-01-01

The Quaternary surficial geologic map of the Mesquite Lake, California-Nevada 30'X60' quadrangle depicts deposit age and geomorphic processes of erosion and deposition, as identified by a composite of remote sensing investigations, laboratory analyses, and field work, in the arid to semi-arid Mojave Desert area, straddling the California-Nevada border. Mapping was motivated by the need to address pressing scientific and social issues such as understanding and predicting the effects of climate and associated hydrologic changes, human impacts on landscapes, ecosystem function, and natural hazards at a regional scale. As the map area lies just to the south of Las Vegas, Nevada, a rapidly expanding urban center, land use pressures and the need for additional construction materials are forecasted for the region. The map contains information on the temporal and spatial patterns of surface processes and hazards that can be used to model specific landscape applications. Key features of the geologic map include: (1) spatially extensive Holocene alluvial deposits that compose the bulk of Quaternary units (~25%), (2) remote sensing and field studies that identified fault scarps or queried faults in the Kingston Wash area, Shadow Mountains, southern Pahrump Valley, Bird Spring Range, Lucy Gray Mountains and Piute Valley, (3) a lineament indicative of potential fault offset is located in Mesquite Valley, (4) active eolian dunes and sand ramps located on the east side of Mesquite, Ivanpah, and Hidden Valleys adjacent to playas, (4) groundwater discharge deposits in southern Pahrump Valley, Spring Mountains, and Lucy Gray Mountains and (5) debris-flow deposits spanning almost the entire Quaternary period in age.

Carbonate deposition, Pyramid Lake subbasin, Nevada: 3. The use of87Sr values in carbonate deposits (tufas) to determine the hydrologic state of paleolake systems

USGS Publications Warehouse

Benson, L.; Peterman, Z.

1996-01-01

Sierran rivers that discharge to the Lahontan basin have much lower (???4.5%o) ??87Sr values than the Humboldt River which drains northeastern Nevada. The ??87Sr values of tufas deposited during the last lake cycle were used to determine when Humboldt derived Sr entered the Pyramid Lake subbasin. Prior to ~ 15,000 yr B.P., the Humboldt River flowed to the Smoke Creek-Black Rock Desert subbasin. During the recession of Lake Lahontan, the Humboldt River diverted to the Carson Desert subbasin. This study has demonstrated that 87Sr can be used to determine drainage histories of multi-basin lake systems if the ??87Sr values of rivers that discharge to the basins are sufficiently different. ?? 1995 Elsevier Science B.V. All rights reserved.

Mixed-layer kerolite/stevensite from the Amargosa Desert, Nevada

USGS Publications Warehouse

Eberl, Dennis D.; Jones, Blair F.; Khoury, Hani N.

1982-01-01

Mixed-layer clays composed of randomly interstratified kerolite/stevensite occur as lake and/or spring deposits of probable Pliocene and Pleistocene age in the Amargosa Desert of southern Nevada, U.S.A. The percentage of expandable layers of these clays, determined from computer-simulated X-ray diffractograms, ranges from almost 0 to about 80%. This range in expandabilities most likely results from differences in solution chemistry and/or temperature at the time of formation. An average structural formula for the purest clay (sample P-7), a clay with about 70% expandable layers, is:[(Mg2.72Al0.07Fe0.03Li0.09)(Si3.96Al0.04)O10(OH)0.2]-0.21[X+0.21]+0.21The data suggest that talc, kerolite, and stevensite form a continuous structural series based on layer charge.

Calcium carbonate nucleation in an alkaline lake surface water, Pyramid Lake, Nevada, USA

USGS Publications Warehouse

Reddy, Michael M.; Hoch, Anthony

2012-01-01

Calcium concentration and calcite supersaturation (Ω) needed for calcium carbonate nucleation and crystal growth in Pyramid Lake (PL) surface water were determined during August of 1997, 2000, and 2001. PL surface water has Ω values of 10-16. Notwithstanding high Ω, calcium carbonate growth did not occur on aragonite single crystals suspended PL surface water for several months. However, calcium solution addition to PL surface-water samples caused reproducible calcium carbonate mineral nucleation and crystal growth. Mean PL surface-water calcium concentration at nucleation was 2.33 mM (n = 10), a value about nine times higher than the ambient PL surface-water calcium concentration (0.26 mM); mean Ω at nucleation (109 with a standard deviation of 8) is about eight times the PL surface-water Ω. Calcium concentration and Ω regulated the calcium carbonate formation in PL nucleation experiments and surface water. Unfiltered samples nucleated at lower Ω than filtered samples. Calcium concentration and Ω at nucleation for experiments in the presence of added particles were within one standard deviation of the mean for all samples. Calcium carbonate formation rates followed a simple rate expression of the form, rate (mM/min) = A (Ω) + B. The best fit rate equation "Rate (Δ mM/Δ min) = -0.0026 Ω + 0.0175 (r = 0.904, n = 10)" was statistically significant at greater than the 0.01 confidence level and gives, after rearrangement, Ω at zero rate of 6.7. Nucleation in PL surface water and morphology of calcium carbonate particles formed in PL nucleation experiments and in PL surface-water samples suggest crystal growth inhibition by multiple substances present in PL surface water mediates PL calcium carbonate formation, but there is insufficient information to determine the chemical nature of all inhibitors.

Calcium Carbonate Nucleation in an Alkaline Lake Surface Water, Pyramid Lake, Nevada, USA

USGS Publications Warehouse

Reddy, M.M.; Hoch, A.

2012-01-01

Calcium concentration and calcite supersaturation (??) needed for calcium carbonate nucleation and crystal growth in Pyramid Lake (PL) surface water were determined during August of 1997, 2000, and 2001. PL surface water has ?? values of 10-16. Notwithstanding high ??, calcium carbonate growth did not occur on aragonite single crystals suspended PL surface water for several months. However, calcium solution addition to PL surface-water samples caused reproducible calcium carbonate mineral nucleation and crystal growth. Mean PL surface-water calcium concentration at nucleation was 2.33 mM (n = 10), a value about nine times higher than the ambient PL surface-water calcium concentration (0.26 mM); mean ?? at nucleation (109 with a standard deviation of 8) is about eight times the PL surface-water ??. Calcium concentration and ?? regulated the calcium carbonate formation in PL nucleation experiments and surface water. Unfiltered samples nucleated at lower ?? than filtered samples. Calcium concentration and ?? at nucleation for experiments in the presence of added particles were within one standard deviation of the mean for all samples. Calcium carbonate formation rates followed a simple rate expression of the form, rate (mM/min) = A (??) + B. The best fit rate equation "Rate (?? mM/?? min) = -0.0026 ?? + 0.0175 (r = 0.904, n = 10)" was statistically significant at greater than the 0.01 confidence level and gives, after rearrangement, ?? at zero rate of 6.7. Nucleation in PL surface water and morphology of calcium carbonate particles formed in PL nucleation experiments and in PL surface-water samples suggest crystal growth inhibition by multiple substances present in PL surface water mediates PL calcium carbonate formation, but there is insufficient information to determine the chemical nature of all inhibitors. ?? 2011 U.S. Government.

FORECASTS AND SENSITIVITY OF PCB BIOACCUMULATION IN FISH OF LAKE HARTWELL, SOUTH CAROLINA, USA

EPA Science Inventory

The EPA aquatic ecosystem model AQUATOX was applied to the Twelvemile Creek arm of Lake Hartwell, which received 400,000 lbs of PCBs from the Sangamo-Weston Superfund Site near Clemson, South Carolina, USA, from 1955 until the early 1990s. AQUATOX was used to characterize food we...

Mercury levels, reproduction, and hematology in western grebes from three California Lakes, USA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elbert, R.A.; Anderson, D.W.

1998-02-01

Twenty-three healthy adult western and Clark`s grebes (Aechmorphorus occidentalis and Aechmorphorus clarkii) were collected at three study sites in California, USA, in 1992: Clear Lake, Lake County; Eagle Lake, Lassen County; and Tule Lake, Siskiyou County. Liver, kidney, breast muscle, and brain were analyzed for total mercury (Hg) concentration (ppm wet weight), and blood was analyzed for various blood parameters. Clear Lake birds had greater Hg concentrations in kidney, breast muscle, and brain than birds from the other two lakes whereas liver concentrations were not statistically different. Average concentrations for Clear Lake birds were 2.74 ppm for liver, 2.06 ppmmore » for kidney, 1.06 ppm for breast muscle, and 0.28 ppm for brain. The tissue levels of kidney, breast muscle, and brain at the other two study sites were one half the levels found at Clear Lake. These mean tissue levels were near, but below, those known to cause adverse effects. When data from all sites were merged, kidney, breast muscle, and brain concentrations are positively correlated to each other. Liver concentrations were not correlated to any other value. Brain Hg concentrations were also negatively correlated to blood potassium and blood phosphorus levels. Kidney Hg levels were positively correlated to percent blood heterophils and negatively correlated to percent eosinophils, suggesting that mercury levels might be affecting immune function. These biomarkers could not be related to any obvious ecological effects.« less

Lake Mead, NV

NASA Technical Reports Server (NTRS)

1982-01-01

Lake Mead, Nevada, (36.0N, 114.5E) where the water from the Colorado River empties after it's 273 mile journey through the Grand Canyon of Arizona is the subject of this photo. Other features of interest are Hoover Dam on the south shore of Lake Mead where cheap hydroelectric power is secondary to the water resources made available in this northern desert region and the resort city of Las Vegas, just to the west of Lake Mead.

Unraveling the volcanic and post-volcanic history at Upsal Hogback, Fallon, Nevada, USA

NASA Astrophysics Data System (ADS)

Anderson, E.; Cousens, B.

2013-12-01

Upsal Hogback is a < 25 ka phreatomagmatic volcanic center situated near Fallon, Nevada. The volcano neighbors two other young volcanic complexes: the Holocene Soda Lakes maars and Rattlesnake Hill, a ~ 1 Ma volcanic neck (Shevenell et al., 2005). These volcanoes lie on the transition between the Sierra Nevada and the Basin and Range province, as well as on the edge of the Walker Lane. Upsal Hogback includes two to four vents, fewer than mapped by Morrison (1964), and can be divided into north (one vent) and south (three potential vents) complexes. The vents all produced phreatomagmatic eruptions resulting in tuff rings composed primarily of coarse, indurated lapilli tuffs with abundant volcanic bombs. Ash tuffs are infrequent, as are structures such as crossbedding. The bombs and lapilli include olivine and plagioclase phenocrysts. The basalts are alkaline and have intraplate-type normalized incompatible element patterns. Both complexes are enriched in LREE compared to HREE, though the north complex overall has lower concentrations of the REE. The flat HREE pattern is indicative of spinel peridotite mantle source. Epsilon Nd values for the north complex are +2.50+/-0.02 and for the south complex are +2.83+/-0.02. The magmas appear to have an enriched asthenospheric mantle source. Bomb samples show that eruptions from the two complexes are geochemically distinguishable both in major and trace elements, suggesting that the two complexes tapped different magma types during eruptions that likely occurred at slightly different times. The proximity of Upsal Hogback to Fallon makes constraining its age important to characterize the hazard to the city. It lies above the Wono ash bed, dated at 25,000 years (Fultz et al., 1983), and tufa deposited over the edifice is dated at 11,100 +/- 100 and 8,600 +/- 200 years (Benson et al., 1992; Broecker and Kaufman, 1965). 40Ar/39Ar total gas age by Shevenell et al. (2005) dated the volcano at 0.60 +/- 0.09 Ma, but with no plateau

White-faced ibis DDE-related reproductive problems continue at Carson Lake, Nevada

USGS Publications Warehouse

Henny, C.J.; Herron, G.B.

1988-01-01

Organochlorine, mercury, and selenium contamination was studied in White-faced Ibis (Plegadis chihi) nesting at Carson Lake, Nevada in 1985 and 1986. DDE was detected in 138 of 140 eggs sampled. Eggshell thickness was negatively correlated with residues of DDE. DDE residues in ibis eggs, unlike residues in most other wading bird eggs from the Great Basin have not declined during the last decade. At DDE levels in eggs above 4 ppm (wet weight), clutch size and productivity decreased, and the incidence of cracked eggs increased. Assuming that 4 ppm DOE is the critical residue level, 40% of the nesting population in 1985 and 1986 was adversely impacted by DDE, with a net loss of 20% of the population' s expected .production. Most eggs containing high levels (up to 29 ppm) also contained DDT, which implies the source was recently-used DDT. No evidence of breeding ground DDE-DDT contamination was found.

Unusual Holocene and late Pleistocene carbonate sedimentation in Bear Lake, Utah and Idaho, USA

USGS Publications Warehouse

Dean, W.; Rosenbaum, J.; Skipp, G.; Colman, S.; Forester, R.; Liu, A.; Simmons, K.; Bischoff, J.

2006-01-01

Bear Lake (Utah-Idaho, USA) has been producing large quantities of carbonate minerals of varying mineralogy for the past 17,000 years. The history of sedimentation in Bear Lake is documented through the study of isotopic ratios of oxygen, carbon, and strontium, percent organic carbon, percent CaCO3, X-ray diffraction mineralogy, HCl-leach inorganic geochemistry, and magnetic properties on samples from three piston cores. Historically, the Bear River, the main source of water for Great Salt Lake, did not enter Bear Lake until it was artificially diverted into the lake at the beginning of the 20th century. However, during the last glacial interval, the Bear River did enter Bear Lake depositing red, calcareous, silty clay. About 18,000 years ago, the Bear River became disconnected from Bear Lake. A combination of warmer water, increased evaporation, and increased organic productivity triggered the precipitation of calcium carbonate, first as calcite. As the salinity of the lake increased due to evaporation, aragonite began to precipitate about 11,000 years ago. Aragonite is the dominant mineral that accumulated in bottom sediments of the lake during the Holocene, comprising an average of about 70 wt.% of the sediments. Aragonite formation in a large, cold, oligotrophic, high latitude lake is highly unusual. Lacustrine aragonite usually is found in small, saline lakes in which the salinity varies considerably over time. However, Bear Lake contains endemic ostracodes and fish, which indicate that the chemistry of the lake has remained fairly constant for a long time. Stable isotope data from Holocene aragonite show that the salinity of Bear Lake increased throughout the Holocene, but never reached highly evolved values of ??18O in spite of an evaporation-dominated water balance. Bear Lake hydrology combined with evaporation created an unusual situation that produced large amounts of aragonite, but no evaporite minerals.

Lakes: recent research and restoration strategies

Treesearch

Karen L. Pope; Jonathan W. Long

2014-01-01

The Sierra Nevada and southern Cascade Range support thousands of montane lakes, from small, remote tarns to iconic destinations such as Lake Tahoe. Their beauty and recreational opportunities instill high social value, in particular by serving as destinations for hiking, camping, swimming, and fishing. Lakes also have high ecological value because they support a...

Evaluating lake stratification and temporal trends by using near-continuous water-quality data from automated profiling systems for water years 2005-09, Lake Mead, Arizona and Nevada

USGS Publications Warehouse

Veley, Ronald J.; Moran, Michael J.

2012-01-01

The U.S. Geological Survey, in cooperation with the National Park Service and Southern Nevada Water Authority, collected near-continuous depth-dependent water-quality data at Lake Mead, Arizona and Nevada, as part of a multi-agency monitoring network maintained to provide resource managers with basic data and to gain a better understanding of the hydrodynamics of the lake. Water-quality data-collection stations on Lake Mead were located in shallow water (less than 20 meters) at Las Vegas Bay (Site 3) and Overton Arm, and in deep water (greater than 20 meters) near Sentinel Island and at Virgin and Temple Basins. At each station, near-continual depth-dependent water-quality data were collected from October 2004 through September 2009. The data were collected by using automatic profiling systems equipped with multiparameter water-quality sondes. The sondes had sensors for temperature, specific conductance, dissolved oxygen, pH, turbidity, and depth. Data were collected every 6 hours at 2-meter depth intervals (for shallow-water stations) or 5-meter depth intervals (for deep-water stations) beginning at 1 meter below water surface. Data were analyzed to determine water-quality conditions related to stratification of the lake and temporal trends in water-quality parameters. Three water-quality parameters were the main focus of these analyses: temperature, specific conductance, and dissolved oxygen. Statistical temporal-trend analyses were performed for a single depth at shallow-water stations [Las Vegas Bay (Site 3) and Overton Arm] and for thermally-stratified lake layers at deep-water stations (Sentinel Island and Virgin Basin). The limited period of data collection at the Temple Basin station prevented the application of statistical trend analysis. During the summer months, thermal stratification was not observed at shallow-water stations, nor were major maxima or minima observed for specific-conductance or dissolved-oxygen profiles. A clearly-defined thermocline

Exposure and effects of perfluoroalkyl compounds on tree swallows nesting at Lake Johanna in east central Minnesota, USA

USGS Publications Warehouse

Custer, Christine M.; Custer, Thomas W.; Schoenfuss, Heiko L.; Poganski, Beth H.; Solem, Laura

2012-01-01

Tree swallow (Tachycineta bicolor) samples were collected at a reference lake and a nearby lake (Lake Johanna) in east central Minnesota, USA contaminated with perfluorinated carboxylic and sulfonic acids. Tissues were analyzed for a suite of 13 perfluoroalkyl compounds (PFCs) to quantify exposure and to determine if there was an association between egg concentrations of PFCs and reproductive success of tree swallows. Concentrations of perfluoroocatane sulfonate (PFOS) were elevated in all tree swallow tissues from Lake Johanna compared to tissues collected at the reference lake. Other PFCs, except for two, were elevated in blood plasma at Lake Johanna compared to the reference lake. PFOS was the dominant PFC (>75%) at Lake Johanna, but accounted for <50% of total PFCs at the reference lake. There was a negative association between concentrations of PFOS in eggs and hatching success. Reduced hatching success was associated with PFOS levels as low as 150 ng/g wet weight.

Pyramid Lake Renewable Energy Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

John Jackson

2008-03-14

The Pyramid Lake Paiute Tribe is a federally recognized Tribe residing on the Pyramid Lake Reservation in western Nevada. The funding for this project was used to identify blind geothermal systems disconnected from geothermal sacred sites and develop a Tribal energy corporation for evaluating potential economic development for profit.

MISR Sees the Sierra Nevadas in Stereo

NASA Technical Reports Server (NTRS)

2000-01-01

These MISR images of the Sierra Nevada mountains near the California-Nevada border were acquired on August 12, 2000 during Terra orbit 3472. On the left is an image from the vertical-viewing (nadir) camera. On the right is a stereo 'anaglyph' created using the nadir and 45.6-degree forward-viewing cameras, providing a three-dimensional view of the scene when viewed with red/blue glasses. The red filter should be placed over your left eye. To facilitate the stereo viewing, the images have been oriented with north toward the left.

Some prominent features are Mono Lake, in the center of the images; Walker Lake, to its left; and Lake Tahoe, near the lower left. This view of the Sierra Nevadas includes Yosemite, Kings Canyon, and Sequoia National Parks. Mount Whitney, the highest peak in the contiguous 48 states (elev. 14,495 feet), is visible near the righthand edge. Above it (to the east), the Owens Valley shows up prominently between the Sierra Nevada and Inyo ranges.

Precipitation falling as rain or snow on the Sierras feeds numerous rivers flowing southwestward into the San Joaquin Valley. The abundant fields of this productive agricultural area can be seen along the lower right; a large number of reservoirs that supply water for crop irrigation are apparent in the western foothills of the Sierras. Urban areas in the valley appear as gray patches; among the California cities that are visible are Fresno, Merced, and Modesto.

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

Geohydrologic reconnaissance of Lake Mead National Recreation Area; Las Vegas Wash to Opal Mountain, Nevada

USGS Publications Warehouse

Laney, R.L.

1981-01-01

The study is a geohydrologic reconnaissance of about 170 square miles in the Lake Mead National Recreation Area from Las Vegas Wash to Opal Mountain, Nevada. The study is one of a series that describes the geohydrology of the recreation area and that indentifies areas where water supplies can be developed. Precipitation in this arid area is about 5 inches per year. Streamflow is seasonal and extremely variable except for that in the Colorado River, which adjoins the area. Pan evaporation is more than 20 times greater than precipitation; therefore, regional ground-water supplies are meager except near the Colorado River, Lake Mead, and Lake Mohave. Large ground-water supplies can be developed near the river and lakes, and much smaller supplies may be obtained in a few favorable locations farther from the river and lakes. Ground water in most of the areas probably contains more than 1,000 milligrams per liter of dissolved solids, but water that contains less than 1,000 milligrams per liter of dissolved solids can be obtained within about 1 mile of the lakes. Crystalline rocks of metamorphic, intrusive and volcanic origin crop out in the area. These rocks are overlain by conglomerate and mudstone of the Muddy Creek Formation, gravel and conglomerate of the older alluvium, and sand and gravel of the Chemehuevi Formation and younger alluvium. The crystalline rocks, where sufficiently fractured, yield water to springs and would yield small amounts of water to favorably located wells. The poorly cemented and more permeable beds of the older alluvium, Chemehuevi Formation, and younger alluvium are the better potential aquifers, particularly along the Colorado River and Lakes Mead and Mohave. Thermal springs in the gorge of the Colorado River south of Hoover Dam discharge at least 2,580 acre-feet per year of water from the volcanic rocks and metamorphic and plutonic rocks. The discharge is much greater than could be infiltrated in the drainage basin above the springs

Seasonal changes in the chemistry and biology of a meromictic lake (Big Soda Lake, Nevada, U.S.A.)

USGS Publications Warehouse

Cloern, J.E.; Cole, B.E.; Oremland, R.S.

1983-01-01

Big Soda Lake is an alkaline, saline lake with a permanent chemocline at 34.5 m and a mixolimnion that undergoes seasonal changes in temperature structure. During the period of thermal stratification, from summer through fall, the epilimnion has low concentrations of dissolved inorganic nutrients (N, Si) and CH4, and low biomass of phytoplankton (chlorophyll a ca. 1 mgm -3). Dissolved oxygen disappears near the compensation depth for algal photosynthesis (ca. 20 m). Surface water is transparent so that light is present in the anoxic hypolimnion, and a dense plate of purple sulfur photosynthetic bacteria (Ectothiorhodospira vacuolata) is present just below 20 m (Bchl a ca. 200 mgm-3). Concentrations of N H4+, Si, and CH4 are higher in the hypolimnion than in the epilimnion. As the mixolimnion becomes isothermal in winter, oxygen is mixed down to 28 m. Nutrients (NH4+, Si) and CH4 are released from the hypolimnion and mix to the surface, and a diatom bloom develops in the upper 20 m (chlorophyll a > 40 mgm-3). The deeper mixing of oxygen and enhanced light attenuation by phytoplankton uncouple the anoxic zone and photic zone, and the plate of photosynthetic bacteria disappears (Bchl a ca.10mgm-3). Hence, seasonal changes in temperature distribution and mixing create conditions such that the primary producer community is alternately dominated by phytoplankton and photosynthetic bacteria: the phytoplankton may be nutrient-limited during periods of stratification and the photosynthetic bacteria are light-limited during periods of mixing. ?? 1983 Dr W. Junk Publishers.

Potential climatic refugia in semi-arid, temperate mountains: plant and arthropod assemblages associated with rock glaciers, talus slopes, and their forefield wetlands, Sierra Nevada, California, USA

Treesearch

Constance I. Millar; Robert D. Westfall; Angela Evenden; Jeffrey G. Holmquist; Jutta Schmidt-Gengenbach; Rebecca S. Franklin; Jan Nachlinger; Diane L. Delany

2015-01-01

Unique thermal and hydrologic regimes of rock-glacier and periglacial talus environments support little-studied mountain ecosystems. We report the first studies of vascular plant and arthropod diversity for these habitats in the central Sierra Nevada, California, USA. Surfaces of active rock glaciers develop scattered islands of soil that provide habitat for vegetation...

Investigating Holocene Glacial and Pluvials Events in the Sierra Nevada of California

NASA Astrophysics Data System (ADS)

Ashford, J.; Sickman, J. O.; Lucero, D. M.; Kirby, M.; Gray, A. B.

2016-12-01

Understanding interannual and decadal variation in snowfall and extreme hydrologic events in the Sierra Nevada is hampered by short instrumental record and uncertainty caused by extrapolating paleoclimate data from lower elevation systems to the alpine snow deposition zone. Longer paleo records from high elevation systems are necessary to provide a more accurate record of snow water content and extreme precipitation events over millennial timescales that can be used to test hypotheses regarding teleconnections between Pacific climate variability and water supply and flood risk in California. In October 2013 we collected sediment cores from Pear Lake, an alpine lake in Sequoia National Park. The cores were split and characterized by P-wave velocity, magnetic susceptibility and density scanning along with grain-size analysis at 1-2 cm increments. Radiocarbon dates indicate that the Pear Lake cores contain a 13.5K year record of lake sediment. In contrast to other Sierra Nevada lakes previously cored by our group, high-resolution scanning revealed alternating fine grained, light-dark bands (1 mm to 5 mm thick) for most of the Pear Lake core length. This pattern was interrupted at intervals by homogenous clasts (up to 75 mm thick) ranging in grain size from sand to gravel up to 1 cm diameter. The sand to gravel sized clasts are most likely associated with extreme precipitation events. Preliminary grain-size analysis results show evidence of isolated extreme hydrologic events and sections of increased event frequency which we hypothesize are the result of atmospheric rivers intersecting the southern Sierra Nevada outside of the snow covered period.

A paleoseismic transect across the northwestern Basin and Range Province, northwestern Nevada and northeastern California, USA

USGS Publications Warehouse

Personius, Stephen; Briggs, Richard; Maharrey, J. Zebulon; Angster, Stephen J.; Mahan, Shannon

2017-01-01

We use new and existing data to compile a record of ∼18 latest Quaternary large-magnitude surface-rupturing earthquakes on 7 fault zones in the northwestern Basin and Range Province of northwestern Nevada and northeastern California. The most recent earthquake on all faults postdates the ca. 18–15 ka last glacial highstand of pluvial Lake Lahontan and other pluvial lakes in the region. These lacustrine data provide a window in which we calculate latest Quaternary vertical slip rates and compare them with rates of modern deformation in a global positioning system (GPS) transect spanning the region. Average vertical slip rates on these fault zones range from 0.1 to 0.8 mm/yr and total ∼2 mm/yr across a 265-km-wide transect from near Paradise Valley, Nevada, to the Warner Mountains in California. We converted vertical slip rates to horizontal extension rates using fault dips of 30°–60°, and then compared the extension rates to GPS-derived rates of modern (last 7–9 yr) deformation. Our preferred fault dip values (45°–55°) yield estimated long-term extension rates (1.3–1.9 mm/yr) that underestimate our modern rate (2.4 mm/yr) by ∼21%–46%. The most likely sources of this underestimate are geologically unrecognizable deformation from moderate-sized earthquakes and unaccounted-for coseismic off-fault deformation from large surface-rupturing earthquakes. However, fault dip values of ≤40° yield long-term rates comparable to or greater than modern rates, so an alternative explanation is that fault dips are closer to 40° than our preferred values. We speculate that the large component of right-lateral shear apparent in the GPS signal is partitioned on faults with primary strike-slip displacement, such as the Long Valley fault zone, and as not easily detected oblique slip on favorably oriented normal faults in the region.

Benthic nutrient sources to hypereutrophic upper Klamath Lake, Oregon, USA.

PubMed

Kuwabara, James S; Topping, Brent R; Lynch, Dennis D; Carter, James L; Essaid, Hedeff I

2009-03-01

Three collecting trips were coordinated in April, May, and August 2006 to sample the water column and benthos of hypereutrophic Upper Klamath Lake (OR, USA) through the annual cyanophyte bloom of Aphanizomenon flos-aquae. A pore-water profiler was designed and fabricated to obtain the first high-resolution (centimeter-scale) estimates of the vertical concentration gradients of macro- and micronutrients for diffusive-flux determinations. A consistently positive benthic flux for soluble reactive phosphorus (SRP) was observed with solute release from the sediment, ranging between 0.4 and 6.1 mg/m(2)/d. The mass flux over an approximate 200-km(2) lake area was comparable in magnitude to riverine inputs. An additional concern related to fish toxicity was identified when dissolved ammonium also displayed consistently positive benthic fluxes of 4 to 134 mg/m(2)/d, again comparable to riverine inputs. Although phosphorus was a logical initial choice by water quality managers for the limiting nutrient when nitrogen-fixing cyanophytes dominate, initial trace-element results from the lake and major inflowing tributaries suggested that the role of iron limitation on primary productivity should be investigated. Dissolved iron became depleted in the lake water column during the course of the algal bloom, while dissolved ammonium and SRP increased. Elevated macroinvertebrate densities, at least of the order of 10(4) individuals/m(2), suggested that the diffusive-flux estimates may be significantly enhanced by bioturbation. In addition, heat-flux modeling indicated that groundwater advection of nutrients could also significantly contribute to internal nutrient loading. Accurate environmental assessments of lentic systems and reasonable expectations for point-source management require quantitative consideration of internal solute sources.

Benthic nutrient sources to hypereutrophic Upper Klamath Lake, Oregon, USA

USGS Publications Warehouse

Kuwabara, J.S.; Topping, B.R.; Lynch, D.D.; Carter, J.L.; Essaid, H.I.

2009-01-01

Three collecting trips were coordinated in April, May, and August 2006 to sample the water column and benthos of hypereutrophic Upper Klamath Lake (OR, USA) through the annual cyanophyte bloom of Aphanizomenon flos-aquae. A porewater profiler was designed and fabricated to obtain the first high-resolution (centimeter-scale) estimates of the vertical, concentration gradients of macro- and micronutrients for diffusive-flux determinations. A consistently positive benthic flux for soluble reactive phosphorus (SRP) was observed with solute release from the sediment, ranging between 0.4 and 6.1 mg/m2/d. The mass flux over an approximate 200-km2 lake area was comparable in magnitude to riverine inputs. An additional concern, related to fish toxicity was identified when dissolved ammonium also displayed consistently positive benthic fluxes of 4 to 134 mg/m2/d, again, comparable to riverine inputs. Although phosphorus was a logical initial choice by water quality managers for the limiting nutrient when nitrogen-fixing cyanophytes dominate, initial trace-element results from the lake and major inflowing tributaries suggested that the role of iron limitation on primary productivity should be investigated. Dissolved iron became depleted in the lake water column during the course of the algal bloom, while dissolved ammonium and SRP increased. Elevated macroinvertebrate densities, at least of the order of 104 individuals/m2, suggested, that the diffusive-flux estimates may be significantly enhanced, by bioturbation. In addition, heat-flux modeling indicated that groundwater advection of nutrients could also significantly contribute to internal nutrient loading. Accurate environmental assessments of lentic systems and reasonable expectations for point-source management require quantitative consideration of internal solute sources ?? 2009 SETAC.

Arsenite as an electron donor for anoxygenic photosynthesis: Description of three strains of Ectothiorhodospria from Mono Lake, California, and Big Soda Lake, Nevada

USGS Publications Warehouse

McCann, Shelley; Boren, Alison; Hernandez-Maldonado, Jaime; Stoneburner, Brendon; Saltikov, Chad W; Stolz, John F.; Oremland, Ronald S.

2017-01-01

Three novel strains of photosynthetic bacteria from the family Ectothiorhodospiraceae were isolated from soda lakes of the Great Basin Desert, USA by employing arsenite (As(III)) as the sole electron donor in the enrichment/isolation process. Strain PHS-1 was previously isolated from a hot spring in Mono Lake, while strain MLW-1 was obtained from Mono Lake sediment, and strain BSL-9 was isolated from Big Soda Lake. Strains PHS-1, MLW-1, and BSL-9 were all capable of As(III)-dependent growth via anoxygenic photosynthesis and contained homologs of arxA, but displayed different phenotypes. Comparisons were made with three related species: Ectothiorhodospira shaposhnikovii DSM 2111, Ectothiorhodospira shaposhnikovii DSM 243T, and Halorhodospira halophila DSM 244. All three type cultures oxidized arsenite to arsenate but did not grow with As(III) as the sole electron donor. DNA–DNA hybridization indicated that strain PHS-1 belongs to the same species as Ect. shaposhnikovii DSM 2111 (81.1% sequence similarity), distinct from Ect. shaposhnikovii DSM 243T (58.1% sequence similarity). These results suggest that the capacity for light-driven As(III) oxidation is a common phenomenon among purple photosynthetic bacteria in soda lakes. However, the use of As(III) as a sole electron donor to sustain growth via anoxygenic photosynthesis is confined to novel isolates that were screened for by this selective cultivation criterion.

Time trends (1983-1999) for organochlorines and polybrominated diphenyl ethers in rainbow smelt (Osmerus mordax) from Lakes Michigan, Huron and Superior, USA

USGS Publications Warehouse

Chernyak, Sergei M.; Rice, Clifford P.; Quintal, Richard T.; Begnoche, Linda J.; Hickey, James P.; Vinyard, Bryan T.

2005-01-01

The U.S. Geological Service Great Lakes Science Center has archived rainbow smelt (Osmerus mordax) collected from the early 1980s to the present. These fish were collected to provide time- and site-dependent contaminant residue data needed by researchers and managers to fill critical data gaps regarding trends and behavior of persistent organic contaminants in the Great Lakes ecosystem. In the present study, data are presented for concentrations of several organochlorine (OC) contaminants in the archived smelt, including DDT, polychlorinated biphenyls (PCBs), toxaphene, and chlordanes in Lakes Michigan and Huron (MI, USA) and in Lake Superior (MN, USA). The trends for all the OCs were declining as a first-order decay over the sampled time series (1983/1985–1993/1999) with the exception of toxaphene in Lake Superior and PCBs at the Charlevoix/Little Traverse Bay site in Lake Michigan. Concentration of the emerging contaminant, polybrominated diphenyl ethers (PBDEs), also was traced from its apparent entry into this ecosystem in approximately 1980 until 1999. Time trends for the PBDEs were increasing exponentially at all sites, with concentration-doubling times varying from 1.58 to 2.94 years.

Sediment sources in the Lake Tahoe Basin, California-Nevada; preliminary results of a four-year study, August 1983-September 1987

USGS Publications Warehouse

Hill, B.R.; Hill, J.R.; Nolan, K.M.

1988-01-01

Data were collected during a 4-yr study of sediment sources in four drainage basins tributary to Lake Tahoe, California-Nevada. The study areas include the Blackwood, General, Edgewood, and Logan House Creek basins. Data include changes in bank and bed positions at channel cross sections; results of stream-channel mapping; analyses of bank and bed material samples; tabulations of bed material point counts; measured rates of hillslope erosion; dimensions of gullies; suspended-sediment data collected during synoptic snowmelt sampling; and physiographic data for the four study basins. (USGS)

Floor of Lake Tahoe, California and Nevada

USGS Publications Warehouse

Dartnell, Peter; Gibbons, Helen

2011-01-01

Lake-floor depths shown by color, from light tan (shallowest) to blue (deepest). Arrows on map (C) show orientations of perspective views. A, view toward McKinney Bay over blocks tumbled onto the lake floor by a massive landslide 10s to 100s of thousands of years ago; dark triangular block near center is approximately 1.5 km (0.9 mi) across and 120 m (390 ft) high. B, view toward South Lake Tahoe and Emerald Bay (on right) over sediment waves as much as 10 m (30 ft) high, created by sediment flowing down the south margin of the lake. Slopes appear twice as steep as they are. Lake-floor imagery from U.S. Geological Survey (USGS) multibeam bathymetric data and U.S. Army Corps of Engineers bathymetric lidar data. Land imagery generated by overlaying USGS digital orthophoto quadrangles (DOQs) on USGS digital elevation models (DEMs). All data available at http://tahoe.usgs.gov/.

Influence of Diagenesis on Bioavailable Phosphorus in Lake Mendota, USA

NASA Astrophysics Data System (ADS)

Hoffman, A.; Armstrong, D.; Lathrop, R.; Penn, M.

2013-12-01

Phosphorus (P) is a major driver of productivity in many freshwater systems and in excess P can cause a variety of deleterious effects. Lake Mendota, located in Madison, Wisconsin (USA), is a eutrophic calcareous lake that is influenced by both urban and agricultural sources. As measures have been implemented to control point and non-point source pollution, internal sources, including release by sediments, has become more important. We collected multiple sediment cores from seven depositional basins to determine how diagenesis is influencing the bioavailability of sediment P. Cores were sliced in 1-cm intervals and analyzed for total P (TP), various P fractions, total metals, and multiple stable isotopes. While the average amount of total P that was bioavailable was 64.8%, the range noted was 39.2% to 88.6%. Spatial differences existed among the cores when comparing TP and bioavailable P among the cores. Depth profiles elucidated temporal differences as occasional increases in TP with depth were noted. These increases were found to contain a higher percent of bioavailable P. This variation was explored to determine if it resulted from differences in source material, for example inorganic P formed by diagenesis of organic P (algal derived) rather than soil P from external inputs. Saturation index modeling using MINEQL+ suggests that phosphorus concentrations in Lake Mendota pore waters are influenced by precipitation of vivianite (Fe3(PO4)2●8H2O) and certain calcium phosphates. However, hydroxyl apatite (Ca5(PO4)3(OH)), was highly supersaturated, indicating that precipitation of hydroxyl apatite is hindered and not important in controlling phosphate concentrations in these sediments. Yet even more important than precipitation reactions, adsorption/desorption characteristics of P seem to play a major role in P bioavailability. Sediment 210Pb and 137Cs activity profiles indicate differences exist among sedimentation rates for the various depositional sites in Lake

Lake Mead, NV

NASA Technical Reports Server (NTRS)

1973-01-01

Lake Mead, Nevada, (36.0N, 114.5E) where the water from the Colorado River empties after it's 273 mile journey through the Grand Canyon of Arizona is the subject of this photo. Other features of interest are Hoover Dam on the south shore of Lake Mead where cheap hydroelectric power is secondary to the water resources made available in this northern desert region and the resort city of Las Vegas, just to the west of Lake Mead. In this harsh desert environment, color infrared photography readily penetrates haze, detects and portrays vegetation as shades of red.

Timing of lake-level changes for a deep last-glacial Lake Missoula: optical dating of the Garden Gulch area, Montana, USA

NASA Astrophysics Data System (ADS)

Smith, Larry N.; Sohbati, Reza; Buylaert, Jan-Pieter; Lian, Olav B.; Murray, Andrew; Jain, Mayank

2018-03-01

Glaciolacustrine sediments in the Clark Fork River valley at Garden Gulch, near Drummond, Montana, USA record highstand positions of the ice-dammed glacial Lake Missoula and repeated subaerial exposure. During these highstands the lake was at greater than 65% of its recognized maximum capacity. The initial lake transgression deposited a basal sand unit. Subsequent cycles of lake-level fluctuations are recorded by sequences of laminated and cross laminated silt, sand, and clay deformed by periglacial processes during intervening periods of lower lake levels. Optically stimulated luminescence (OSL) dating of quartz sand grains, using single-aliquot regenerative-dose procedures, was carried out on 17 samples. Comparison of infrared stimulated luminescence (IRSL) from K-rich feldspar to OSL from quartz for all the samples suggests that they were well bleached prior to deposition and burial. Ages for the basal sand and overlying glaciolacustrine exposure surfaces are indistinguishable within one standard deviation, and give a weighted mean age of 20.9 ± 1.3 ka (n = 11). Based on sedimentological and stratigraphic analysis we infer that the initial transgression, and at least six cycles of lake-level fluctuation, occurred over time scales of decades to ∼2 ka. Bioturbated sandy slopewash dated at 10.6 ± 0.9 ka and 11.9 ± 1.2 ka unconformably overlies the upper glaciolacustrine deposits. The uppermost sediments, above the glaciolacustrine section, are younger than the Glacier Peak tephra (13.7-13.4 cal ka B.P.), which was deposited across parts of the drained lake basin, but has not been found at Garden Gulch. Our study indicates that glacial Lake Missoula reached >65 percent of maximum capacity by about 20.9 ± 1.3 ka and either partially or completely drained twelve times from this position. Rapid lowering from the lake's highstand position due to ice-dam failure likely led to scour in the downstream portions of the glacial Lake Missoula basin and megafloods in the

Finger Lake Region, NY State, USA

NASA Technical Reports Server (NTRS)

1992-01-01

This view of the central portion of upstate New York, centers on the Finger Lakes. The large city on the shore of Lake Ontario, is Rochester. Although the city, being a business, educational and technical center, has no heavy industry, the outline of the city shows fairly well in the snow, but not as well as the outlines of industrial cities elsewhere in the world. The Finger Lakes are large linear lakes carved out by glaciers during the last ice age.

Anthropogenic nitrogen deposition induces rapid ecological changes in alpine lakes of Colorado Front Range (USA)

USGS Publications Warehouse

Wolfe, A.P.; Baron, Jill S.; Cornett, R.J.

2001-01-01

Recent sediments from two alpine lakes (> 3300 m asl) in the Colorado Front Range (USA) register marked and near-synchronous changes that are believed to represent ecological responses to enhanced atmospheric deposition of fixed nitrogen from anthropogenic sources. Directional shifts in sediment proxies include greater representations of mesotrophic diatoms and increasingly depleted δ15N values. These trends are particularly pronounced since ~ 1950, and appear to chronicle lake responses to excess N derived from agricultural and industrial sources to the east. The rate and magnitude of recent ecological changes far exceed the context of natural variability, as inferred from comparative analyses of a long core capturingthe entire 14,000-year postglacial history of one of the lakes. Nitrogen deposition to these seemingly pristine natural areas has resulted in subtle but detectable limnological changes that likely represent the beginning of a stronger response to nitrogen enrichment.

Holocene climate on the Modoc Plateau, northern California, USA: The view from Medicine Lake

USGS Publications Warehouse

Starratt, Scott W.

2009-01-01

Medicine Lake is a small (165 ha), relatively shallow (average 7.3 m), intermediate elevation (2,036 m) lake located within the summit caldera of Medicine Lake volcano, Siskiyou County, California, USA. Sediment cores and high-resolution bathymetric and seismic reflection data were collected from the lake during the fall of 1999 and 2000. Sediments were analyzed for diatoms, pollen, density, grain size (sand/mud ratio), total organic carbon (TOC), and micro-scale fabric analysis. Using both 14C (AMS) dating and tephrochronology, the basal sediments were estimated to have been deposited about 11,400 cal year BP, thus yielding an estimated average sedimentation rate of about 20.66 cm/1,000 year. The lowermost part of the core (11,400–10,300 cal year BP) contains the transition from glacial to interglacial conditions. From about 11,000–5,500 cal year BP, Medicine Lake consisted of two small, steep-sided lakes or one lake with two steep-sided basins connected by a shallow shelf. During this time, both the pollen (Abies/Artemisia ratio) and the diatom (Cyclotella/Navicula ratio) evidences indicate that the effective moisture increased, leading to a deeper lake. Over the past 5,500 years, the pollen record shows that effective moisture continued to increase, and the diatom record indicates fluctuations in the lake level. The change in the lake level pattern from one of the increasing depths prior to about 6,000 cal year BP to one of the variable depths may be related to changes in the morphology of the Medicine Lake caldera associated with the movement of magma and the eruption of the Medicine Lake Glass Flow about 5,120 cal year BP. These changes in basin morphology caused Medicine Lake to flood the shallow shelf which surrounds the deeper part of the lake. During this period, the Cyclotella/Navicula ratio and the percent abundance of Isoetes vary, suggesting that the level of the lake fluctuated, resulting in changes in the shelf area

Nutrient and sediment transport in streams of the Lake Tahoe basin: a 30-year retrospective

Treesearch

Robert Coats

2004-01-01

Lake Tahoe, widely renowned for its astounding clarity and deep blue color, lies at an elevation of 1,898 meters (m) in the central Sierra Nevada, astride the California-Nevada border. The volume of the lake is 156 cubic kilometers (km3), and its surface area is 501 square kilometers (km2), 38 percent of the total basin...

Distribution of total and methyl mercury in sediments along Steamboat Creek (Nevada, USA)

USGS Publications Warehouse

Stamenkovic, J.; Gustin, M.S.; Marvin-DiPasquale, M. C.; Thomas, B.A.; Agee, J.L.

2004-01-01

In the late 1800s, mills in the Washoe Lake area, Nevada, used elemental mercury to remove gold and silver from the ores of the Comstock deposit. Since that time, mercury contaminated waste has been distributed from Washoe Lake, down Steamboat Creek, and to the Truckee River. The creek has high mercury concentrations in both water and sediments, and continues to be a constant source of mercury to the Truckee River. The objective of this study was to determine concentrations of total and methyl mercury (MeHg) in surface sediments and characterize their spatial distribution in the Steamboat Creek watershed. Total mercury concentrations measured in channel and bank sediments did not decrease downstream, indicating that mercury contamination has been distributed along the creek's length. Total mercury concentrations in sediments (0.01-21.43 ??g/g) were one to two orders of magnitude higher than those in pristine systems. At 14 out of 17 sites, MeHg concentrations in streambank sediments were higher than the concentrations in the channel, suggesting that low banks with wet sediments might be important sites of mercury methylation in this system. Both pond/wetland and channel sites exhibited high potential for mercury methylation (6.4-30.0 ng g-1 day-1). Potential methylation rates were positively correlated with sulfate reduction rates, and decreased as a function of reduced sulfur and MeHg concentration in the sediments. Potential demethylation rate appeared not to be influenced by MeHg concentration, sulfur chemistry, DOC, sediment grain size or other parameters, and showed little variation across the sites (3.7-7.4 ng g-1 day-1). ?? 2003 Elsevier B.V. All rights reserved.

Comparison of 15 evaporation methods applied to a small mountain lake in the northeastern USA

USGS Publications Warehouse

Rosenberry, D.O.; Winter, T.C.; Buso, D.C.; Likens, G.E.

2007-01-01

Few detailed evaporation studies exist for small lakes or reservoirs in mountainous settings. A detailed evaporation study was conducted at Mirror Lake, a 0.15 km2 lake in New Hampshire, northeastern USA, as part of a long-term investigation of lake hydrology. Evaporation was determined using 14 alternate evaporation methods during six open-water seasons and compared with values from the Bowen-ratio energy-budget (BREB) method, considered the standard. Values from the Priestley-Taylor, deBruin-Keijman, and Penman methods compared most favorably with BREB-determined values. Differences from BREB values averaged 0.19, 0.27, and 0.20 mm d-1, respectively, and results were within 20% of BREB values during more than 90% of the 37 monthly comparison periods. All three methods require measurement of net radiation, air temperature, change in heat stored in the lake, and vapor pressure, making them relatively data intensive. Several of the methods had substantial bias when compared with BREB values and were subsequently modified to eliminate bias. Methods that rely only on measurement of air temperature, or air temperature and solar radiation, were relatively cost-effective options for measuring evaporation at this small New England lake, outperforming some methods that require measurement of a greater number of variables. It is likely that the atmosphere above Mirror Lake was affected by occasional formation of separation eddies on the lee side of nearby high terrain, although those influences do not appear to be significant to measured evaporation from the lake when averaged over monthly periods. ?? 2007 Elsevier B.V. All rights reserved.

Hydrologic Setting and Conceptual Hydrologic Model of the Walker River Basin, West-Central Nevada

USGS Publications Warehouse

Lopes, Thomas J.; Allander, Kip K.

2009-01-01

The Walker River is the main source of inflow to Walker Lake, a closed-basin lake in west-central Nevada. Between 1882 and 2008, agricultural diversions resulted in a lake-level decline of more than 150 feet and storage loss of 7,400,000 acre-ft. Evaporative concentration increased dissolved solids from 2,500 to 17,000 milligrams per liter. The increase in salinity threatens the survival of the Lahontan cutthroat trout, a native species listed as threatened under the Endangered Species Act. This report describes the hydrologic setting of the Walker River basin and a conceptual hydrologic model of the relations among streams, groundwater, and Walker Lake with emphasis on the lower Walker River basin from Wabuska to Hawthorne, Nevada. The Walker River basin is about 3,950 square miles and straddles the California-Nevada border. Most streamflow originates as snowmelt in the Sierra Nevada. Spring runoff from the Sierra Nevada typically reaches its peak during late May to early June with as much as 2,800 cubic feet per second in the Walker River near Wabuska. Typically, 3 to 4 consecutive years of below average streamflow are followed by 1 or 2 years of average or above average streamflow. Mountain ranges are comprised of consolidated rocks with low hydraulic conductivities, but consolidated rocks transmit water where fractured. Unconsolidated sediments include fluvial deposits along the active channel of the Walker River, valley floors, alluvial slopes, and a playa. Sand and gravel deposited by the Walker River likely are discontinuous strata throughout the valley floor. Thick clay strata likely were deposited in Pleistocene Lake Lahontan and are horizontally continuous, except where strata have been eroded by the Walker River. At Walker Lake, sediments mostly are clay interbedded with alluvial slope, fluvial, and deltaic deposits along the lake margins. Coarse sediments form a multilayered, confined-aquifer system that could extend several miles from the shoreline

Mapping of accumulated nitrogen in the sediment pore water of a eutrophic lake in Iowa, USA

USGS Publications Warehouse

Iqbal, M.Z.; Fields, C.L.

2009-01-01

A large pool of nitrogen in the sediment pore fluid of a eutrophic lake in Iowa, USA, was mapped in this study. Previously, the lake had supported fishing and boating, but today it no longer supports its designated uses as a recreational water body. In the top 5 cm of the lake bottom, the pore water nitrogen ranges between 3.1 and 1,250 ??g/cm3 of sediments, with an average of 160.3 ??g/cm3. Vertically, nitrate concentrations were measured as 153 ??g/cm3 at 0-10 cm, 162 ??g/cm3 at 10-20 cm, and 32 ??g/cm3 at 20-30 cm. Nitrate mass distribution was quantified as 3.67 ?? 103 kg (65%) in the bottom sediments, 172 kg (3%) in suspended particulates, and 1.83 ?? 103 kg (32%) in the dissolved phase. Soil runoff nutrients arrive at the lake from the heavily fertilized lands in the watershed. Upon sedimentation, a large mass of nitrogen desorbs from mineral particles to the relatively immobile pore fluid. Under favorable conditions, this nitrogen diffuses back into the water column, thereby dramatically limiting the lake's capability to process incoming nutrients from farmlands. Consequently, a condition of oxygen deficiency disrupts the post-season biological activities in the lake. ?? 2008 Springer-Verlag.

Reconstruction of 20th Century Atmospheric Deposition Rates in the Sierra Nevada (California) using Spheroidal Carbonaceous Particles

NASA Astrophysics Data System (ADS)

Heard, A.; Sickman, J. O.; Rose, N.

2012-12-01

Atmospheric nitrogen deposition is altering biogeochemical cycles and ecological processes in high-elevation aquatic ecosystems. A need for stricter standards based on measurable ecological effects has been identified as an important step towards their long-term protection. One of the challenges with identifying ecological thresholds is a lack of knowledge of background conditions (pre- industrial) and changes that may have occurred prior to extensive monitoring programs. However, this information can be obtained using paleolimnological approaches. We are investigating historic atmospheric deposition in the Sierra Nevada using spheroidal carbonaceous particles (SCPs) in lake sediments. SCPs are strong geochemical indicators of anthropogenic atmospheric deposition because they are only produced by industrial combustion of fossil fuels---there are no natural sources. We detected SCPs as early as 1870 at Moat Lake in the eastern Sierra Nevada. SCP concentrations increased over time, peaking in the mid-1980's (2,399 gDM-1) while SCP accumulation rates peaked in the early 1920's (105 no, cm-2 yr-1) (Figure 1). Lakes along the western slope of the Sierra (Pear and Emerald) show similar patterns although differences vary by site and are likely explained by watershed characteristics and proximity to emission sources. SCP concentrations at Pear and Emerald lakes peak 10-15 years earlier than Moat. A consistent decrease was observed at Pear and Moat following the peak concentrations until present. Present day concentrations are 556 gDM-1 at Moat and 473 gDM-1 at Pear. At Emerald lake SCPs also initially decreased starting in 1964, but an increasing trend is observed from 1995 through present. These data improve our understanding of historic atmospheric deposition patterns and are being used to inform additional palaeolimnological research, including diatom analyses, with the broader objective of reconstructing historic nitrogen deposition and estimating critical loads for

Remote Sensing as a Tool to Track Algal Blooms in the Great Salt Lake, Utah, USA

NASA Astrophysics Data System (ADS)

Bradt, S. R.; Wurtsbaugh, W. A.; Naftz, D.; Moore, T.; Haney, J.

2006-12-01

The Great Salt Lake is a large hypersaline, terminal water body in northern Utah, USA. The lake has both a significant economic importance to the local community as a source of brine shrimp and mineral resources, as well as, an ecological importance to large numbers of migratory waterfowl. Due to nutrient input from sewage treatment plants, sections of the Great Salt Lake are subjected to highly eutrophic conditions. One of the main tributaries, Farmington Bay, experiences massive blooms of cyanobacteria which can reach concentrations in excess of 300 mg l-1 in the bay. Effects of these blooms can be observed stretching into the rest of the lake. The detrimental outcomes of the blooms include unsightly scums, foul odor and the danger of cyanobacterial toxins. While the blooms have an obvious effect on Farmington Bay, it is quite possible that the cyanobacteria impact a much wider area of the lake as currents move eutrophic water masses. Of particular interest is the reaction of brine shrimp to the plumes of cyanobacteria-rich water leaving Farmington Bay. We are employing remote sensing as a tool to map the distribution of algae throughout the lake and produce lake-wide maps of water quality on a regular basis. On-lake reflectance measurements have been coupled with MODIS satellite imagery to produce a time series of maps illustrating changes in algal distribution. The successes and shortcomings of our remote sensing technique will be a central topic of this presentation.

Recent increases in sediment and nutrient accumulation in Bear Lake, Utah/Idaho, USA

USGS Publications Warehouse

Smoak, J.M.; Swarzenski, P.W.

2004-01-01

This study examines historical changes in sediment and nutrient accumulation rates in Bear Lake along the northeastern Utah/Idaho border, USA. Two sediment cores were dated by measuring excess 210Pb activities and applying the constant rate of supply (CRS) dating model. Historical rates of bulk sediment accumulation were calculated based on the ages within the sediment cores. Bulk sediment accumulation rates increased throughout the last 100 years. According to the CRS model, bulk sediment accumulation rates were <25mg cm-2 year-1 prior to 1935. Between 1935 and 1980, bulk sediment accumulation rates increased to approximately 40mg cm -2 year-1. This increase in sediment accumulation probably resulted from the re-connection of Bear River to Bear Lake. Bulk sediment accumulation rates accelerated again after 1980. Accumulation rates of total phosphorus (TP), total nitrogen (TN), total inorganic carbon (TIC), and total organic carbon (TOC) were calculated by multiplying bulk sediment accumulation rates times the concentrations of these nutrients in the sediment. Accumulation rates of TP, TN, TIC, and TOC increased as a consequence of increased bulk sediment accumulation rates after the re-connection of Bear River with Bear Lake.

Lake Mead, NV

NASA Image and Video Library

1973-06-22

SL2-03-192 (22 June 1973) --- Lake Mead, Nevada, (36.0N, 114.5E) where the water from the Colorado River empties after it's 273 mile journey through the Grand Canyon of Arizona is the subject of this photo. Other features of interest are Hoover Dam on the south shore of Lake Mead where cheap hydroelectric power is secondary to the water resources made available in this northern desert region and the resort city of Las Vegas, just to the west of Lake Mead. In this harsh desert environment, color infrared photography readily penetrates haze, detects and portrays vegetation as shades of red. Photo credit: NASA

Hydrologic data for the Walker River Basin, Nevada and California, water years 2010–14

USGS Publications Warehouse

Pavelko, Michael T.; Orozco, Erin L.

2015-12-10

Walker Lake is a threatened and federally protected desert terminal lake in western Nevada. To help protect the desert terminal lake and the surrounding watershed, the Bureau of Reclamation and U.S. Geological Survey have been studying the hydrology of the Walker River Basin in Nevada and California since 2004. Hydrologic data collected for this study during water years 2010 through 2014 included groundwater levels, surface-water discharge, water chemistry, and meteorological data. Groundwater levels were measured in wells, and surface-water discharge was measured in streams, canals, and ditches. Water samples for chemical analyses were collected from wells, streams, springs, and Walker Lake. Chemical analyses included determining physical properties; the concentrations of major ions, nutrients, trace metals, dissolved gases, and radionuclides; and ratios of the stable isotopes of hydrogen and oxygen. Walker Lake water properties and meteorological parameters were monitored from a floating platform on the lake. Data collection methods followed established U.S. Geological Survey guidelines, and all data are stored in the National Water Information System database. All of the data are presented in this report and accessible on the internet, except multiple-depth Walker Lake water-chemistry data, which are available only in this report.

Forest biomass estimated from MODIS and FIA data in the Lake States: MN, WI and MI, USA

Treesearch

Daolan Zheng; Linda S. Heath; Mark J. Ducey

2007-01-01

This study linked the Moderate Resolution Imaging Spectrometer and USDA Forest Service, Forest Inventory and Analysis (FIA) data through empirical models established using high-resolution Landsat Enhanced Thematic Mapper Plus observations to estimate aboveground biomass (AGB) in three Lake States in the north-central USA. While means obtained from larger sample sizes...

A Stable Isotope Study of Fluid-Rock Interactions in the Saddlebag Lake Roof Pendant, Sierra Nevada, California

NASA Astrophysics Data System (ADS)

Lojasiewicz, I.; Hartman, S. M.; Holk, G. J.; Paterson, S. R.

2015-12-01

The Saddlebag Lake Pendant (SLP) is a ~ 100 km2 zone of Ordovician-Cretaceous metasedimentary and metavolcanic rocks just east of the 95-85 Ma Tuolumne Intrusive Complex (TIC) in the Sierra Nevada of central California. Western SLP and adjacent parts of TIC are affected by the Steelhead Lake Shear Zone (SLSZ), with leucogranitic dikes, abundant qz-tm veins, ductile epidote-chlorite alteration, and massive qz veins. While TIC shows uniform stable isotope values, isotope studies of other Sierra Nevada pendants evidence diversity of fluid sources: Jurassic seawater, Cretaceous magmatic fluids, metamorphic fluids, and meteoric-hydrothermal fluids. We conducted a stable isotope study of 49 samples from units across the SLSZ, focusing on the shear zone. Unlike other pendants, both δ18 O and δD values from SLSZ showed great variability, and most samples were not in isotopic equilibrium. Overall, δ18 O mineral values ranged from -1.5‰(plag) to +15.8‰(bt); mineral δD values ranged from -140‰(tm) to -67‰(bt). TIC δ18 O was +7.8 to +10.0 (plag) and +4.8 to +9.2 (tm), normal magmatic values, and δD were -105 to -75. Paleozoic and Triassic metasedimentary units had most qz δ18 O from +11.3 to +15.8, so within metamorphic range, and δD from -100 to -72 (ep and tm). Jurassic metasedimentary units (Sawmill) and Triassic metavolcanics (Koip) had largest isotopic variability: δ18 O qz from +8.1 to +14.8, plag from -1.1 to +11.8, but ep and tm between +1.3 and +9.3 and δD between -108 and -81. All lower (submagmatic) isotopic values were from a wider, possibly transtensional, part of the SLSZ, transected by Sawmill Canyon. Although TIC and many of the Paleozoic units do not show isotopic evidence for alteration, the Koip and Sawmill units were likely infiltrated by later magmatic waters, and then subjected to very localized meteoric water infiltration in the area surrounding Sawmill Canyon.

Paleomagnetism and Anisotropy of Magnetic Susceptibility study of the Miocene Jack Springs Tuff (Nevada, USA)

NASA Astrophysics Data System (ADS)

Shields, S.; Petronis, M. S.; Pluhar, C. J.; Gordon, L.

2014-12-01

The mid-Miocene Jack Springs Tuff (JST) outcrops across the western Mina Deflection accommodation zone, west-central Nevada and into eastern California. Previously, the source location for the JST was unknown, yet recent studies northwest of Mono Lake, CA have identified a relatively un-rotated structural block in which to reference the paleomagnetic data. Although new studies have indicated that this block may be rotated up to 13º, we argue that the probable source area is located near the Bodie Hills, CA. At this site, the paleomagnetic reference direction is D = 353°, I = 43°, α95 = 7.7° (Carlson et al, 2013). Based on these data, the JST can be used to measure absolute vertical-axis rotation as well as enable reconstruction of the paleo-topography using the corrected anisotropy of magnetic susceptibility (AMS) data. A total of 19 sites were sampled to constrain Cenozoic to recent vertical axis rotation within the region and AMS experiments were conducted to determine the flow direction of the JST. Curie point estimates indicate that the JST ranges in titanium concentration from 0.042 to 1.10, indicating a low to moderate titanomagnetite phase (Akimoto, 1962). Demagnetization experiments reveal mean destructive fields of the NRM ranging between 15mT and 40mT suggesting that both multi-domain to pseudo-single domain grains are the dominant ferromagnetic phases that carry the remanence and AMS fabric. Preliminary paleomagnetic data yield stable single component demagnetization behavior for most sites that, after structural correction, indicate clockwise vertical axis rotation ranging from +20°± 10° to +60°± 11° between multiple fault blocks. The uncorrected AMS data yield oblate magnetic fabrics that can be used to infer the transport direction, source region, and paleovalley geometry of the JST. These data are tentatively interpreted to indicate west to east transport of the JST across the Mono Basin region into the Mina Deflection that was erupted and

Spatiotemporal analysis of microbial community dynamics during seasonal stratification events in a freshwater lake (Grand Lake, OK, USA)

PubMed Central

Morrison, Jessica M.; Baker, Kristina D.; Zamor, Richard M.; Nikolai, Steve; Elshahed, Mostafa S.

2017-01-01

Many freshwater lakes undergo seasonal stratification, where the formation of phototrophic blooms in the epilimnion and subsequent sedimentation induces hypoxia/anoxia in the thermocline and hypolimnion. This autochthonously produced biomass represents a major seasonal organic input that impacts the entire ecosystem. While the limnological aspects of this process are fairly well documented, relatively little is known regarding the microbial community response to such events, especially in the deeper anoxic layers of the water column. Here, we conducted a spatiotemporal survey of the particle-associated and free-living microbial communities in a warm monomictic freshwater reservoir (Grand Lake O’ the Cherokees) in northeastern Oklahoma, USA. Pre-stratification samples (March) harbored a homogeneous community throughout the oxygenated water column dominated by typical oligotrophic aquatic lineages (acl clade within Actinobacteria, and Flavobacterium within the Bacteroidetes). The onset of phototrophic blooming in June induced the progression of this baseline community into two distinct trajectories. Within the oxic epilimnion, samples were characterized by the propagation of phototrophic (Prochlorococcus), and heterotrophic (Planctomycetes, Verrucomicrobia, and Beta-Proteobacteria) lineages. Within the oxygen-deficient thermocline and hypolimnion, the sedimentation of surface biomass induced the development of a highly diverse community, with the enrichment of Chloroflexi, “Latescibacteria”, Armatimonadetes, and Delta-Proteobacteria in the particle-associated fraction, and Gemmatimonadetes and “Omnitrophica” in the free-living fraction. Our work documents the development of multiple spatially and temporally distinct niches during lake stratification, and supports the enrichment of multiple yet-uncultured and poorly characterized lineages in the lake’s deeper oxygen-deficient layers, an ecologically relevant microbial niche that is often overlooked in

Holocene Paleoenvironment of the North-central Great Basin: Preliminary Results from Favre Lake, Northern Ruby Mountains, Nevada

NASA Astrophysics Data System (ADS)

Starratt, S.; Wahl, D.; Wan, E.; Anderson, L.; Wanket, J.; Olson, H.; Lloyd-Davies, T.; Kusler, J.

2009-12-01

Little is known about Holocene climate variability in north-central Nevada. This study aims to assess changes in watershed vegetation, fire history, lake levels and limnological conditions in order to understand secular to millennial-scale changes in regional climate. Favre Lake (2,899 m a.s.l.; 12 m deep; 7.7 hectares) is a flow-through lake in the northern Ruby Mountains. The primary sources of influent, both of which appear to be intermittent, are Castle Lake (2,989 m a.s.l.) and Liberty Lake (3,077 m a.s.l.). The bedrock of the three lake basins is early Paleozoic marble and Mesozoic granite and metamorphic rocks. Bathymetric maps and temperature, pH, salinity, and conductivity profiles have been generated for Favre Lake. Surface samples and a series of cores were also collected using a modified Livingstone piston corer. The presence of the Mazama ash in the basal sediment (~4 m below the sediment/water interface) indicates the record extends to ~7,700 cal yr B.P. Magnetic susceptibility (MS) and loss-on-ignition data indicate that the sediments in the lowest part of the core contain primary and reworked Mazama ash. About 2,000 years ago CaCO3 increased from 2 to 3% of the inorganic sediment. The upper 25 cm of the core are marked by an increase in MS which may indicate increased erosion due to grazing. Between about 7,700 and 6,000 cal yr B.P. the diatom flora is dominated by a diverse assemblage of benthic species. The remainder of the core is dominated by Fragilaria, suggesting that lake level rose and flooded the shelf that surrounds the depocenter of the lake. This is supported by changes in the abundance of the aquatic fern Isoetes. Pinus and Artemisia dominate the pollen record, followed by subordinate levels of Poaceae, Asteraceae, Amaranthaceae, and Sarcobatus. The late early Holocene (7,700-6,000 cal yr B.P.) is dominated by Pinus which is present in reduced amounts during the middle Holocene (6,000-3,000 cal yr B.P.) and then returns to dominance in

Anthropogenic nitrogen deposition induces rapid ecological changes in alpine lakes of the Colorado Front Range (USA)

USGS Publications Warehouse

Wolfe, A.P.; Baron, Jill S.; Cornett, R.J.

2001-01-01

Recent sediments from two alpine lakes (> 3300 m asl) in the Colorado Front Range (USA) register marked and near-synchronous changes that are believed to represent ecological responses to enhanced atmospheric deposition of fixed nitrogen from anthropogenic sources. Directional shifts in sediment proxies include greater representations of mesotrophic diatoms and increasingly depleted ??15N values. These trends are particularly pronounced since ??? 1950, and appear to chronicle lake responses to excess N derived from agricultural and industrial sources to the east. The rate and magnitude of recent ecological changes far exceed the context of natural variability, as inferred from comparative analyses of a long core capturing the entire 14,000-year postglacial history of one of the lakes. Nitrogen deposition to these seemingly pristine natural areas has resulted in subtle but detectable limnological changes that likely represent the beginning of a stronger response to nitrogen enrichment.

Effects of hypolimnetic oxygen addition on mercury bioaccumulation in Twin Lakes, Washington, USA.

PubMed

Beutel, Marc; Dent, Stephen; Reed, Brandon; Marshall, Piper; Gebremariam, Seyoum; Moore, Barry; Cross, Benjamin; Gantzer, Paul; Shallenberger, Ed

2014-10-15

Twin Lakes, located on the Confederated Tribes of the Colville Indian Reservation in eastern Washington, USA, include North Twin Lake (NT) and South Twin Lake (ST). The mesotrophic, dimictic lakes are important recreational fishing sites for both warm-water bass and cold-water trout. To improve summertime cold-water habitat for trout in NT, dissolved oxygen (DO) addition to the hypolimnion, using liquid oxygen as an oxygen gas source, started in 2009. This study assessed mercury (Hg) in the water column, zooplankton and fish, and related water quality parameters, in Twin Lakes from 2009 to 2012. Because methylmercury (MeHg) buildup in lake bottom water is commonly associated with hypolimnetic anoxia, hypolimnetic oxygenation was hypothesized to reduce Hg in bottom waters and biota in NT relative to ST. Oxygen addition led to significantly higher DO (mean hypolimnetic DO: 2-8 mg/L versus <1 mg/L) and lower MeHg (peak mean hypolimnetic MeHg: 0.05-0.2 ng/L versus 0.15-0.4 ng/L) in North Twin. In North Twin, years with higher DO (2009 and 2011) exhibited lower MeHg in bottom waters and lower total Hg in zooplankton, inferring a positive linkage between oxygen addition and lower bioaccumulation. However, when comparing between the two lakes, Hg levels were significantly higher in zooplankton (total Hg range: 100-200 versus 50-100 μg/kg dry weight) and trout (spring 2010 stocking cohort of eastern brook trout mean total Hg: 74.9 versus 49.9 μg/kg wet weight) in NT relative to ST. Lower Hg bioaccumulation in ST compared to NT may be related to bloom dilution in chlorophyll-rich bottom waters, a vertical disconnect between the location of zooplankton and MeHg in the water column, and high binding affinity between sulfide and MeHg in bottom waters. Copyright © 2014 Elsevier B.V. All rights reserved.

Airborne LiDAR analysis and geochronology of faulted glacial moraines in the Tahoe-Sierra frontal fault zone reveal substantial seismic hazards in the Lake Tahoe region, California-Nevada USA

USGS Publications Warehouse

Howle, James F.; Bawden, Gerald W.; Schweickert, Richard A.; Finkel, Robert C.; Hunter, Lewis E.; Rose, Ronn S.; von Twistern, Brent

2012-01-01

We integrated high-resolution bare-earth airborne light detection and ranging (LiDAR) imagery with field observations and modern geochronology to characterize the Tahoe-Sierra frontal fault zone, which forms the neotectonic boundary between the Sierra Nevada and the Basin and Range Province west of Lake Tahoe. The LiDAR imagery clearly delineates active normal faults that have displaced late Pleistocene glacial moraines and Holocene alluvium along 30 km of linear, right-stepping range front of the Tahoe-Sierra frontal fault zone. Herein, we illustrate and describe the tectonic geomorphology of faulted lateral moraines. We have developed new, three-dimensional modeling techniques that utilize the high-resolution LiDAR data to determine tectonic displacements of moraine crests and alluvium. The statistically robust displacement models combined with new ages of the displaced Tioga (20.8 ± 1.4 ka) and Tahoe (69.2 ± 4.8 ka; 73.2 ± 8.7 ka) moraines are used to estimate the minimum vertical separation rate at 17 sites along the Tahoe-Sierra frontal fault zone. Near the northern end of the study area, the minimum vertical separation rate is 1.5 ± 0.4 mm/yr, which represents a two- to threefold increase in estimates of seismic moment for the Lake Tahoe basin. From this study, we conclude that potential earthquake moment magnitudes (Mw) range from 6.3 ± 0.25 to 6.9 ± 0.25. A close spatial association of landslides and active faults suggests that landslides have been seismically triggered. Our study underscores that the Tahoe-Sierra frontal fault zone poses substantial seismic and landslide hazards.

First report of Schistocephalus sp. (Cestoda: Pseudophyllidea) in slimy sculpin, Cottus cognatus Richardson, 1836, from Lake Michigan, U.S.A.

USGS Publications Warehouse

French, J. R. P.; Muzzall, P.M.

2008-01-01

Plerocercoids of Schistocephalus sp. (Diphyllobothriidae) were found in the body cavities of 2 (0.9%) of 209 slimy sculpins, Cottus cognatus, collected in September 2003 from Lake Michigan, south of Manistique, Michigan, U.S.A. Mean intensity was 1. The mean lengths and weights of these 2 thawed, relaxed plerocercoids were 67 and 72 mm and 427 and 554 mg, respectively. The number of segments in each plerocercoid was 113, and both plerocercoids showed upturned edges of the first segment. The identification of these plerocercoids to species is discussed, and the occurrence of Schistocephalus sp. in fish from the Great Lakes is summarized. This is the first report of Schistocephalus in slimy sculpin from Lake Michigan and the second report of Schistocephalus infecting fish from this lake.

The Honey Lake fault zone, northeastern California: Its nature, age, and displacement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wagner, D.L.; Saucedo, G.J.; Grose, T.L.T.

The Honey Lake fault zone of northeastern California is composed of en echelon, northwest trending faults that form the boundary between the Sierra Nevada and the Basin Ranges provinces. As such the Honey Lake fault zone can be considered part of the Sierra Nevada frontal fault system. It is also part of the Walker Lane of Nevada. Faults of the Honey Lake zone are vertical with right-lateral oblique displacements. The cumulative vertical component of displacement along the fault zone is on the order of 800 m and right-lateral displacement is at least 10 km (6 miles) but could be considerablymore » more. Oligocene to Miocene (30 to 22 Ma) age rhyolite tuffs can be correlated across the zone, but mid-Miocene andesites do not appear to be correlative indicating the faulting began in early to mid-Miocene time. Volcanic rocks intruded along faults of the zone, dated at 16 to 8 Ma, further suggest that faulting in the Honey Lake zone was initiated during mid-Miocene time. Late Quaternary to Holocene activity is indicated by offset of the 12,000 year old Lake Lahontan high stand shoreline and the surface rupture associated with the 1950 Fort Sage earthquake.« less

Energy density of lake whitefish Coregonus clupeaformis in Lakes Huron and Michigan

USGS Publications Warehouse

Pothoven, S.A.; Nalepa, T.F.; Madenjian, C.P.; Rediske, R.R.; Schneeberger, P.J.; He, J.X.

2006-01-01

We collected lake whitefish Coregonus clupeaformis off Alpena and Tawas City, Michigan, USA in Lake Huron and off Muskegon, Michigan USA in Lake Michigan during 2002–2004. We determined energy density and percent dry weight for lake whitefish from both lakes and lipid content for Lake Michigan fish. Energy density increased with increasing fish weight up to 800 g, and then remained relatively constant with further increases in fish weight. Energy density, adjusted for weight, was lower in Lake Huron than in Lake Michigan for both small (≤800 g) and large fish (>800 g). Energy density did not differ seasonally for small or large lake whitefish or between adult male and female fish. Energy density was strongly correlated with percent dry weight and percent lipid content. Based on data from commercially caught lake whitefish, body condition was lower in Lake Huron than Lake Michigan during 1981–2003, indicating that the dissimilarity in body condition between the lakes could be long standing. Energy density and lipid content in 2002–2004 in Lake Michigan were lower than data for comparable sized fish collected in 1969–1971. Differences in energy density between lakes were attributed to variation in diet and prey energy content as well as factors that affect feeding rates such as lake whitefish density and prey abundance.

Estimating recharge at Yucca Mountain, Nevada, USA: Comparison of methods

USGS Publications Warehouse

Flint, A.L.; Flint, L.E.; Kwicklis, E.M.; Fabryka-Martin, J. T.; Bodvarsson, G.S.

2002-01-01

Obtaining values of net infiltration, groundwater travel time, and recharge is necessary at the Yucca Mountain site, Nevada, USA, in order to evaluate the expected performance of a potential repository as a containment system for high-level radioactive waste. However, the geologic complexities of this site, its low precipitation and net infiltration, with numerous mechanisms operating simultaneously to move water through the system, provide many challenges for the estimation of the spatial distribution of recharge. A variety of methods appropriate for arid environments has been applied, including water-balance techniques, calculations using Darcy's law in the unsaturated zone, a soil-physics method applied to neutron-hole water-content data, inverse modeling of thermal profiles in boreholes extending through the thick unsaturated zone, chloride mass balance, atmospheric radionuclides, and empirical approaches. These methods indicate that near-surface infiltration rates at Yucca Mountain are highly variable in time and space, with local (point) values ranging from zero to several hundred millimeters per year. Spatially distributed net-infiltration values average 5 mm/year, with the highest values approaching 20 mm/year near Yucca Crest. Site-scale recharge estimates range from less than 1 to about 12 mm/year. These results have been incorporated into a site-scale model that has been calibrated using these data sets that reflect infiltration processes acting on highly variable temporal and spatial scales. The modeling study predicts highly non-uniform recharge at the water table, distributed significantly differently from the non-uniform infiltration pattern at the surface.

Patterns of volcanism, weathering, and climate history from high-resolution geochemistry of the BINGO core, Mono Lake, California, USA

NASA Astrophysics Data System (ADS)

Zimmerman, S. R.; Starratt, S.; Hemming, S. R.

2012-12-01

Mono Lake, California is a closed-basin lake on the east side of the Sierra Nevada, and inflow from snowmelt dominates the modern hydrology. Changes in wetness during the last glacial period (>12,000 years ago) and over the last 2,000 years have been extensively described, but are poorly known for the intervening period. We have recovered a 6.25 m-long core from ~3 m of water in the western embayment of Mono Lake, which is shown by initial radiocarbon dates to cover at least the last 10,000 years. The sediments of the core are variable, ranging from black to gray silts near the base, laminated olive-green silt through the center, to layers of peach-colored carbonate nodules interbedded with gray and olive silts and pea-green organic ooze. Volcanic tephras from <1 to 8 cm thick occur throughout. Results of 0.5 cm-resolution scanning-X-Ray fluoresence (XRF) analysis describe changes in lithology due to volcanism, erosion, and changing lake level and chemistry. Titanium (Ti) is chemically and biologically unreactive, and records the dominant input, from weathering of Sierra Nevada granite to the west and Miocene and Pliocene volcanic rocks of the Bodie and Adobe Hills to the north, east, and south. The rhyolitic tephras of the Mono-Inyo Craters are much lower in TiO2 than the bedrock (<0.1% vs. 1-2%), and are an unweathered source of K2O (3.5-5%), and thus form dramatic peaks in the K/Ti ratio. Calcium (Ca) and Sr are well correlated throughout the core, and normalization of both by K (detritus + tephra) corresponds with occurrence of carbonate-rich layers. These are a mixture of authigenic precipitates directly precipitated and eroded into the lake during periods of regression. The lowermost 1.5 m of the BINGO core contains the highest proportion of detrital input to Mono Lake over the last ~12,000 years, recorded by high Si, Ti, K, and Fe, in black to dark-gray, fine-grained silts above 10 cm of pure light gray silt. Based on radiocarbon dates of >10,000 calibrated

Geology and mineral resources of the Sheldon-Hart Mountain National Wildlife Refuge Complex (Oregon and Nevada), the Southeastern Oregon and North-Central Nevada, and the Southern Idaho and Northern Nevada (and Utah) Sagebrush Focal Areas: Chapter B in Mineral resources of the Sagebrush Focal Areas of Idaho, Montana, Nevada, Oregon, Utah, and Wyoming

USGS Publications Warehouse

Vikre, Peter G.; Benson, Mary Ellen; Bleiwas, Donald I.; Colgan, Joseph P.; Cossette, Pamela M.; DeAngelo, Jacob; Dicken, Connie L.; Drake, Ronald M.; du Bray, Edward A.; Fernette, Gregory L.; Glen, Jonathan M.G.; Haacke, Jon E.; Hall, Susan M.; Hofstra, Albert H.; John, David A.; Ludington, Stephen; Mihalasky, Mark J.; Rytuba, James J.; Shaffer, Brian N.; Stillings, Lisa L.; Wallis, John C.; Williams, Colin F.; Yager, Douglas B.; Zürcher, Lukas

2016-10-04

SummaryThe U.S. Department of the Interior has proposed to withdraw approximately 10 million acres of Federal lands from mineral entry (subject to valid existing rights) from 12 million acres of lands defined as Sagebrush Focal Areas (SFAs) in Idaho, Montana, Nevada, Oregon, Utah, and Wyoming (for further discussion on the lands involved see Scientific Investigations Report 2016–5089–A). The purpose of the proposed action is to protect the greater sage-grouse (Centrocercus urophasianus) and its habitat from potential adverse effects of locatable mineral exploration and mining. The U.S. Geological Survey Sagebrush Mineral-Resource Assessment (SaMiRA) project was initiated in November 2015 and supported by the Bureau of Land Management to (1) assess locatable mineral-resource potential and (2) to describe leasable and salable mineral resources for the seven SFAs and Nevada additions.This chapter summarizes the current status of locatable, leasable, and salable mineral commodities and assesses the potential of selected locatable minerals in lands proposed for withdrawal that span the Nevada, Oregon, Idaho, and Utah borders. In this report, the four study areas evaluated were (1) the Sheldon-Hart Mountain National Wildlife Refuge Complex SFA in Washoe County, Nevada, and Harney and Lake Counties, Oregon; (2) the Southeastern Oregon and North-Central Nevada SFA in Humboldt County, Nevada, and Harney and Malheur Counties, Oregon; (3) the Southern Idaho and Northern Nevada SFA in Cassia, Owyhee, and Twin Falls Counties, Idaho, Elko County, Nevada, and Box Elder County, Utah; and (4) the Nevada additions in Humboldt and Elko Counties, Nevada.

Zooplankton assemblages in montane lakes and ponds of Mount Rainier National Park, Washington State, USA

USGS Publications Warehouse

Larson, G.L.; Hoffman, R.; McIntire, C.D.; Lienkaemper, G.; Samora, B.

2009-01-01

Water quality and zooplankton samples were collected during the ice-free periods between 1988 and 2005 from 103 oligotrophic montane lakes and ponds located in low forest to alpine vegetation zones in Mount Rainier National Park, Washington State, USA. Collectively, 45 rotifer and 44 crustacean taxa were identified. Most of the numerically dominant taxa appeared to have wide niche breadths. The average number of taxa per lake decreased with elevation and generally increased as maximum lake depths increased (especially for rotifers). With one exception, fish presence/absence did not explain the taxonomic compositions of crustacean zooplankton assemblages. Many rotifer species were common members of zooplankton assemblages in montane lakes and ponds in western North America, whereas the crustacean taxa were common to some areas of the west, but not others. Constraints of the environmental variables did not appear to provide strong gradients to separate the distributions of most zooplankton species. This suggests that interspecific competitive interactions and stochastic processes regulate the taxonomic structures of the zooplankton assemblages at the landscape level. Crustacean species that had broad niche breadths were associated with different rotifer taxa across the environmental gradients. Studies of zooplankton assemblages need to address both crustacean and rotifer taxa, not one or the other.

Marine and land active-source seismic imaging of mid-Miocene to Holocene-aged faulting near geothermal prospects at Pyramid Lake, Nevada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eisses, A.; Kell, A.; Kent, G.

Amy Eisses, Annie Kell, Graham Kent, Neal Driscoll, Robert Karlin, Rob Baskin, John Louie, and Satish Pullammanappallil, 2011, Marine and land active-source seismic imaging of mid-Miocene to Holocene-aged faulting near geothermal prospects at Pyramid Lake, Nevada: Geothermal Resources Council Transactions, 35, 7 pp. Preprint at http://crack.seismo.unr.edu/geothermal/Eisses-GRCpaper-sm.pdf The Pyramid Lake fault zone lies within a vitally important area of the northern Walker Lane where not only can transtension can be studied through a complex arrangement of strike-slip and normal faults but also geothermal activity can be examined in the extensional regime for productivity. This study used advanced and economical seismic methodsmore » in attempt to develop the Paiute Tribe’s geothermal reservoir and to expand upon the tectonics and earthquake hazard knowledge of the area. 500 line-kilometers of marine CHIRP data were collected on Pyramid Lake combined with 27 kilometers of vibrator seismic on-land data from the northwest side of the basin were collected in 2010 that highlighted two distinct phases of faulting. Preliminary results suggest that the geothermal fluids in the area are controlled by the late Pleistoceneto Holocene-aged faults and not through the mid-Miocene-aged conduits as originally hypothesized.« less

Cyanide and migratory birds at gold mines in Nevada, USA

USGS Publications Warehouse

Henny, C.J.; Hallock, R.J.; Hill, E.F.

1994-01-01

Since the mid-1980s, cyanide in heap leach solutions and mill tailings ponds at gold mines in Nevada has killed a large but incompletely documented number of wildlife ( gt 9,500 individuals, primarily migratory birds). This field investigation documents the availability of cyanide at a variety of 'typical' Nevada gold mines during 1990 and 1991, describes wildlife reactions to cyanide solutions, and discusses procedures for eliminating wildlife loss from cyanide poisoning. Substantial progress has been made to reduce wildlife loss. About half of the mill tailings ponds (some up to 150 ha) in Nevada have been chemically treated to reduce cyanide concentrations (the number needing treatment is uncertain) and many of the smaller heap leach solution ponds and channels are now covered with netting to exclude birds and most mammals. The discovery of a cyanide gradient in mill tailings ponds (concentration usually 2-3 times higher at the inflow point than at reclaim point) provides new insight into wildlife responses (mortality) observed in different portions of the ponds. Finding dead birds on the tops of ore heaps and associated with solution puddling is a new problem, but management procedures for eliminating this source of mortality are available. A safe threshold concentration of cyanide to eliminate wildlife loss could not be determined from the field data and initial laboratory studies. New analytical methods may be required to assess further the wildlife hazard of cyanide in mining solutions.

Basque Diaspora in the USA and Language Maintenance

ERIC Educational Resources Information Center

Lasagabaster, David

2008-01-01

The Basques first immigrated on a large scale to the USA during the Gold Rush of 1848. After immigrating to the USA, they settled in pockets throughout the West, especially in California, Nevada and Idaho, and it is currently estimated that more than 35,000 Basque-Americans live in these three states. This represents one of the largest…

20th-century glacial-marine sedimentation in Vitus Lake, Bering Glacier, Alaska, U.S.A.

USGS Publications Warehouse

Molnia, B.F.; Post, A.; Carlson, P.R.

1996-01-01

Vitus Lake, the ice-marginal basin at the southeastern edge of Bering Glacier, Alaska, U.S.A., is a site of modern, rapid, glacial-marine sedimentation. Rather than being a fresh-water lake, Vitus Lake is a tidally influenced, marine to brackish embayment connected to the Pacific Ocean by an inlet, the Seal River. Vitus Lake consists of five deep bedrock basins, separated by interbasinal highs. Glacial erosion has cut these basins as much as 250 m below sea level. High-resolution seismic reflection surveys conducted in 1991 and 1993 of four of Vitus Lake's basins reveal a complex, variable three-component acoustic stratigraphy. Although not fully sampled, the stratigraphy is inferred to be primarily glacial-marine units of (1) basal contorted and deformed glacial-marine and glacial sediments deposited by basal ice-contact processes and submarine mass-wasting; (2) acoustically well-stratified glacial-marine sediment, which unconformably overlies the basal unit and which grades upward into (3) acoustically transparent or nearly transparent glacial-marine sediment. Maximum thicknesses of conformable glacial-marine sediment exceed 100 m. All of the acoustically transparent and stratified deposits in Vitus Lake are modern in age, having accumulated between 1967 and 1993. The basins where these three-part sequences of "present-day" glacial-marine sediment are accumulating are themselves cut into older sequences of stratified glacial and glacial-marine deposits. These older units outcrop on the islands in Vitus Lake. In 1967, as the result of a major surge, glacier ice completely filled all five basins. Subsequent terminus retreat, which continued through August 1993, exposed these basins, providing new locations for glacial-marine sediment accumulation. A correlation of sediment thicknesses measured from seismic profiles at specific locations within the basins, with the year that each location became ice-free, shows that the sediment accumulation at some locations

The Conterminous United States Mineral Appraisal Program; background information to accompany folio of geologic, geochemical, geophysical, and mineral resources maps of the Walker Lake 1 degree x 2 degrees Quadrangle, California and Nevada

USGS Publications Warehouse

Stewart, John Harris; Chaffee, M.A.; Dohrenwend, J.C.; John, D.A.; Kistler, R.W.; Kleinhampl, F.J.; Menzie, W.D.; Plouff, Donald; Rowan, L.C.; Silberling, Norman J.

1984-01-01

The Walker Lake 1? by 2? quadrangle in eastern California and western Nevada was studied by an interdisciplinary research team to appraise its mineral resources. The appraisal is based on geological, geochemical, and geophysical field and laboratory investigations, the results of which are published as a folio of maps, figures, and tables, with accompanying discussions. This circular provides background information on the investigations and integrates the information presented in the folio. The selected bibliography lists selected references to the geology, geochemistry, geophysics, and mineral deposits of the Walker Lake 1? by 2? quadrangle.

Clustering of velocities in a GPS network spanning the Sierra Nevada Block, the Northern Walker Lane Belt, and the Central Nevada Seismic Belt, California-Nevada

NASA Astrophysics Data System (ADS)

Savage, J. C.; Simpson, R. W.

2013-09-01

The deformation across the Sierra Nevada Block, the Walker Lane Belt, and the Central Nevada Seismic Belt (CNSB) between 38.5°N and 40.5°N has been analyzed by clustering GPS velocities to identify coherent blocks. Cluster analysis determines the number of clusters required and assigns the GPS stations to the proper clusters. The clusters are shown on a fault map by symbols located at the positions of the GPS stations, each symbol representing the cluster to which the velocity of that GPS station belongs. Fault systems that separate the clusters are readily identified on such a map. Four significant clusters are identified. Those clusters are strips separated by (from west to east) the Mohawk Valley-Genoa fault system, the Pyramid Lake-Wassuk fault system, and the Central Nevada Seismic Belt. The strain rates within the westernmost three clusters approximate simple right-lateral shear (~13 nstrain/a) across vertical planes roughly parallel to the cluster boundaries. Clustering does not recognize the longitudinal segmentation of the Walker Lane Belt into domains dominated by either northwesterly trending, right-lateral faults or northeasterly trending, left-lateral faults.

Clustering of velocities in a GPS network spanning the Sierra Nevada Block, the northern Walker Lane Belt, and the Central Nevada Seismic Belt, California-Nevada

USGS Publications Warehouse

Savage, James C.; Simpson, Robert W.

2013-01-01

The deformation across the Sierra Nevada Block, the Walker Lane Belt, and the Central Nevada Seismic Belt (CNSB) between 38.5°N and 40.5°N has been analyzed by clustering GPS velocities to identify coherent blocks. Cluster analysis determines the number of clusters required and assigns the GPS stations to the proper clusters. The clusters are shown on a fault map by symbols located at the positions of the GPS stations, each symbol representing the cluster to which the velocity of that GPS station belongs. Fault systems that separate the clusters are readily identified on such a map. Four significant clusters are identified. Those clusters are strips separated by (from west to east) the Mohawk Valley-Genoa fault system, the Pyramid Lake-Wassuk fault system, and the Central Nevada Seismic Belt. The strain rates within the westernmost three clusters approximate simple right-lateral shear (~13 nstrain/a) across vertical planes roughly parallel to the cluster boundaries. Clustering does not recognize the longitudinal segmentation of the Walker Lane Belt into domains dominated by either northwesterly trending, right-lateral faults or northeasterly trending, left-lateral faults.

Surface and Airborne Arsenic Concentrations in a Recreational Site near Las Vegas, Nevada, USA

PubMed Central

Goossens, Dirk

2015-01-01

Elevated concentrations of arsenic, up to 7058 μg g-1 in topsoil and bedrock, and more than 0.03 μg m-3 in air on a 2-week basis, were measured in the Nellis Dunes Recreation Area (NDRA), a very popular off-road area near Las Vegas, Nevada, USA. The elevated arsenic concentrations in the topsoil and bedrock are correlated to outcrops of yellow sandstone belonging to the Muddy Creek Formation (≈ 10 to 4 Ma) and to faults crossing the area. Mineralized fluids moved to the surface through the faults and deposited the arsenic. A technique was developed to calculate airborne arsenic concentrations from the arsenic content in the topsoil. The technique was tested by comparing calculated with measured concentrations at 34 locations in the NDRA, for 3 periods of 2 weeks each. We then applied it to calculate airborne arsenic concentrations for more than 500 locations all over the NDRA. The highest airborne arsenic concentrations occur over sand dunes and other zones with a surficial layer of aeolian sand. Ironically these areas show the lowest levels of arsenic in the topsoil. However, they are highly susceptible to wind erosion and emit very large amounts of sand and dust during episodes of strong winds, thereby also emitting much arsenic. Elsewhere in the NDRA, in areas not or only very slightly affected by wind erosion, airborne arsenic levels equal the background level for airborne arsenic in the USA, approximately 0.0004 μg m-3. The results of this study are important because the NDRA is visited by more than 300,000 people annually. PMID:25897667

Are endocrine and reproductive biomarkers altered in contaminant-exposed wild male Largemouth Bass (Micropterus salmoides) of Lake Mead, Nevada/Arizona, USA?

PubMed

Goodbred, Steven L; Patiño, Reynaldo; Torres, Leticia; Echols, Kathy R; Jenkins, Jill A; Rosen, Michael R; Orsak, Erik

2015-08-01

Male Largemouth Bass were sampled from two locations in Lake Mead (USA), a site influenced by treated municipal wastewater effluent and urban runoff (Las Vegas Bay), and a reference site (Overton Arm). Samples were collected in summer (July '07) and spring (March '08) to assess general health, endocrine and reproductive biomarkers, and compare contaminant body burdens by analyzing 252 organic chemicals. Sperm count and motility were measured in spring. Contaminants were detected at much higher frequencies and concentrations in fish from Las Vegas Bay than Overton Arm. Those with the highest concentrations included PCBs, DDTs, PBDEs, galaxolide, and methyl triclosan. Fish from Las Vegas Bay also had higher Fulton condition factor, hepatosomatic index, and hematocrit, and lower plasma 11-ketotestosterone concentration (KT). Gonadosomatic index (GSI) and sperm motility did not differ between sites, but sperm count was lower by nearly 50% in fish from Las Vegas Bay. A positive association between KT and GSI was identified, but this association was nonlinear. On average, maximal GSI was reached at sub-maximal KT concentrations. In conclusion, the higher concentration of contaminant body burdens coupled with reduced levels of KT and sperm count in fish from Las Vegas Bay suggest that male reproductive condition was influenced by contaminant exposures. Also, the nonlinear KT-GSI association provided a framework to understand why GSI was similar between male bass from both sites despite their large difference in KT, and also suggested the existence of post-gonadal growth functions of KT at high concentrations. Published by Elsevier Inc.

Are endocrine and reproductive biomarkers altered in contaminant-exposed wild male Largemouth Bass (Micropterus salmoides) of Lake Mead, Nevada/Arizona, USA?

USGS Publications Warehouse

Goodbred, Steven L.; Patino, Reynaldo; Torres, Leticia; Echols, Kathy R.; Jenkins, Jill A.; Rosen, Michael R.; Orsak, Erik

2015-01-01

Male Largemouth Bass were sampled from two locations in Lake Mead (USA), a site influenced by treated municipal wastewater effluent and urban runoff (Las Vegas Bay), and a reference site (Overton Arm). Samples were collected in summer (July '07) and spring (March '08) to assess general health, endocrine and reproductive biomarkers, and compare contaminant body burdens by analyzing 252 organic chemicals. Sperm count and motility were measured in spring. Contaminants were detected at much higher frequencies and concentrations in fish from Las Vegas Bay than Overton Arm. Those with the highest concentrations included PCBs, DDTs, PBDEs, galaxolide, and methyl triclosan. Fish from Las Vegas Bay also had higher Fulton condition factor, hepatosomatic index, and hematocrit, and lower plasma 11-ketotestosterone concentration (KT). Gonadosomatic index (GSI) and sperm motility did not differ between sites, but sperm count was lower by nearly 50% in fish from Las Vegas Bay. A positive association between KT and GSI was identified, but this association was nonlinear. On average, maximal GSI was reached at sub-maximal KT concentrations. In conclusion, the higher concentration of contaminant body burdens coupled with reduced levels of KT and sperm count in fish from Las Vegas Bay suggest that male reproductive condition was influenced by contaminant exposures. Also, the nonlinear KT-GSI association provided a framework to understand why GSI was similar between male bass from both sites despite their large difference in KT, and also suggested the existence of post-gonadal growth functions of KT at high concentrations.

American white pelican predation on Cui-ui in Pyramid Lake, Nevada

USGS Publications Warehouse

Scoppettone, Gayton G.; Rissler, Peter H.; Fabes, Mark C.; Withers, Donna

2014-01-01

Anthropogenic changes to the Pyramid Lake–Truckee River ecosystem in Nevada are suspected to have altered the predator–prey balance between American white pelican Pelecanus erythrorhynchos and Cui-ui Chasmistes cujus. We estimated the loss of the adult Cui-ui population to pelican predation over a 13-year period by netting and tagging Cui-uis as they aggregated at the mouth of the Truckee River prior to their spawning migration into the Truckee River. Cui-ui access to the Truckee River typically required traversing a shallow delta (a foraging advantage for these American white pelicans). Dams and greater frequency of low stream flows also contributed to American white pelican foraging success. We used tag recoveries from Pyramid Lake's nesting colony of American white pelicans along with an experiment to estimate the chance of tag recovery within the colony to calculate the number of tagged fish taken by American white pelicans. We also used numbered tags to test whether there was a size preference for Cui-uis taken. Our results showed that the primary source of adult Cui-ui mortality was from American white pelican predation in the Truckee River. Within a 13-year period American white pelicans had taken 90% of the tags deployed during the first 7 years of the interval. There was no preference for the size of Cui-uis taken. A better understanding of the effects of heavy cropping by American white pelicans on Cui-ui population dynamics is still needed.

The future of biodiversity in the Sierra Nevada through the Lake Tahoe Basin Looking Glass

Treesearch

Patricia N. Manley

2004-01-01

The Sierra Nevada’s biological distinction and diversity are almost as legendary as its spectacular peaks and beautiful granite landscapes. The Sierra Nevada is recognized as a zoogeographic region on the basis of the coincidence of species ranges (for example, Udvardy 1969, 1975; Welsh 1994). Udvardy (1969) defined the Sierra Nevada bioregion as bounded by the Great...

Change in the forested and developed landscape of the Lake Tahoe basin, California and Nevada, USA, 1940-2002

USGS Publications Warehouse

Raumann, C.G.; Cablk, Mary E.

2008-01-01

The current ecological state of the Lake Tahoe basin has been shaped by significant landscape-altering human activity and management practices since the mid-1850s; first through widespread timber harvesting from the 1850s to 1920s followed by urban development from the 1950s to the present. Consequences of landscape change, both from development and forest management practices including fire suppression, have prompted rising levels of concern for the ecological integrity of the region. The impacts from these activities include decreased water quality, degraded biotic communities, and increased fire hazard. To establish an understanding of the Lake Tahoe basin's landscape change in the context of forest management and development we mapped, quantified, and described the spatial and temporal distribution and variability of historical changes in land use and land cover in the southern Lake Tahoe basin (279 km2) from 1940 to 2002. Our assessment relied on post-classification change detection of multi-temporal land-use/cover and impervious-surface-area data that were derived through manual interpretation, image processing, and GIS data integration for four dates of imagery: 1940, 1969, 1987, and 2002. The most significant land conversion during the 62-year study period was an increase in developed lands with a corresponding decrease in forests, wetlands, and shrublands. Forest stand densities increased throughout the 62-year study period, and modern thinning efforts resulted in localized stand density decreases in the latter part of the study period. Additionally forests were gained from succession, and towards the end of the study period extensive tree mortality occurred. The highest rates of change occurred between 1940 and 1969, corresponding with dramatic development, then rates declined through 2002 for all observed landscape changes except forest density decrease and tree mortality. Causes of landscape change included regional population growth, tourism demands

Temperature Trends in Montane Lakes

NASA Astrophysics Data System (ADS)

Melack, J. M.; Sadro, S.; Jellison, R.

2014-12-01

Long-term temperature trends in lakes integrate hydrological and meteorological factors. We examine temperature trends in a small montane lake with prolonged ice-cover and large seasonal snowfall and in a large saline lake. Emerald Lake, located in the Sierra Nevada (California), is representative of high-elevation lakes throughout the region. No significant trend in outflow temperature was apparent from 1991to 2012. Snowfall in the watershed accounted for 93% of the variability in average summer lake temperatures. Mono Lake (California) lies in a closed, montane basin and is hypersaline and monomictic or meromictic. Temperature profiles have been collected from 1982 to 2010. In the upper water column, the July-August-September water temperatures increased 0.8-1.0°C over the 29 years. This rate of warming is less than published estimates based on satellite-derived skin temperatures and will discussed in the context of general limnological interpretation of temperature trends.

Mono Lake, California as seen from STS-59

NASA Image and Video Library

1994-04-14

STS059-154-160 (9-20 April 1994) --- Orient with Mono Lake, California at the lower right; then the view is westward across the Sierra Nevada into the San Joaquin River drainage. A tiny network of ski trails can be seen on the Mono Lake side of the Sierras, on a line between Mono Lake and the snow-free San Joaquin headwaters. The ski trails mark Mammoth Mountain, where SRL investigators are studying microwave measurements of the water content of snowpacks. Linhof camera.

Duration and severity of Medieval drought in the Lake Tahoe Basin

USGS Publications Warehouse

Kleppe, J.A.; Brothers, D.S.; Kent, G.M.; Biondi, F.; Jensen, S.; Driscoll, N.W.

2011-01-01

Droughts in the western U.S. in the past 200 years are small compared to several megadroughts that occurred during Medieval times. We reconstruct duration and magnitude of extreme droughts in the northern Sierra Nevada from hydroclimatic conditions in Fallen Leaf Lake, California. Stands of submerged trees rooted in situ below the lake surface were imaged with sidescan sonar and radiocarbon analysis yields an age estimate of ∼1250 AD. Tree-ring records and submerged paleoshoreline geomorphology suggest a Medieval low-stand of Fallen Leaf Lake lasted more than 220 years. Over eighty more trees were found lying on the lake floor at various elevations above the paleoshoreline. Water-balance calculations suggest annual precipitation was less than 60% normal from late 10th century to early 13th century AD. Hence, the lake’s shoreline dropped 40–60 m below its modern elevation. Stands of pre-Medieval trees in this lake and in Lake Tahoe suggest the region experienced severe drought at least every 650–1150 years during the mid- and late-Holocene. These observations quantify paleo-precipitation and recurrence of prolonged drought in the northern Sierra Nevada.

Hydrogeology of the Lake Tahoe Basin, California and Nevada

USGS Publications Warehouse

Plume, Russell W.; Tumbusch, Mary L.; Welborn, Toby L.

2009-01-01

Ground water in the Lake Tahoe basin is the primary source of domestic and municipal water supply and an important source of inflow to Lake Tahoe. Over the past 30-40 years, Federal, State, and local agencies, and research institutions have collected hydrologic data to quantify the ground-water resources in the Lake Tahoe basin. These data are dispersed among the various agencies and institutions that collected the data and generally are not available in a format suitable for basin-wide assessments. To successfully and efficiently manage the ground-water resources throughout the Lake Tahoe basin, the U.S. Geological Survey (USGS) in cooperation with the U.S. Forest Service (USFS) compiled and evaluated the pertinent geologic, geophysical, and hydrologic data, and built a geodatabase incorporating the consolidated and standardized data for the Lake Tahoe basin that is relevant for examining the extent and characteristics of the hydrogeologic units that comprise the aquifers. The geodatabase can be accessed at http://water.usgs.gov/lookup/getspatial?SIM3063.

Geochemical evidence for hydroclimatic variability over the last 2460 years from Crevice Lake in Yellowstone National Park, USA

USGS Publications Warehouse

Stevens, L.R.; Dean, W.E.

2008-01-01

A 2460-year-long hydroclimatic record for Crevice Lake, Yellowstone National Park, Montana was constructed from the ??18O values of endogenic carbonates. The ??18O record is compared to the Palmer Hydrologic Drought Index (PHDI) and Pacific Decadal Oscillation (PDO) indices, as well as inferred discharge of the Yellowstone River. During the last century, high ??18O values coincide with drought conditions and the warm phase of the PDO index. Low ??18O values coincide with wet years and a negative PDO index. Comparison of tree-ring inferred discharge of the Yellowstone River with the ??18O record over the last 300 years indicates that periods of high discharge (i.e., wet winters with significant snow pack) correspond with low ??18O values. Extrapolating this relationship we infer wet winters and high river discharge for the periods of 1090-1030, 970-870, 670-620, and 500-430 cal years BP. The wet intervals at 670 and 500 cal BP are synchronous with similar events in Banff, Canada and Walker Lake, Nevada. The wet intervals at 970 and 670 cal BP overlap with wet intervals at Walker Lake and major drought events identified in the western Great Basin. These results suggest that the northern border of Yellowstone National Park straddles the boundary between Northern Rocky Mountains and Great Basin climate regimes. ?? 2007 Elsevier Ltd and INQUA.

Mariano Lake Mine

EPA Pesticide Factsheets

Mariano Lake Mine is located in the Mariano Lake Chapter of the Navajo Nation, approximately 25 miles east of Gallup, N.M in McKinley County. EPA is working with Navajo Nation Environmental Protection Agency (NNEPA) to oversee cleanup work by Chevron U.S.A

Impact of Camping on Soil Properties at Strawberry Lake, North Dakota, USA

NASA Astrophysics Data System (ADS)

Brevik, Eric C.; Tibor, Matthew A.

2014-05-01

Recreational activity at campsites can cause compaction and metal contamination of soils. This study compared the bulk densities, penetration resistance values, organic matter contents, and Zn, Mn, and Cu contents of soils sampled from zones of varying recreational activity within the campsites at Strawberry Lake, North Dakota, USA. The results of this study showed that there were statistically significant increases in the soil bulk densities and soil penetration resistance values compared to the controls. However, the low recreational intensity has not compacted the surface soils beyond an average of 1.36 g cm-3, which is not dense enough to hinder the root growth of the surrounding vegetation. There were no statistically significant differences between the soil organic matter content of the different activity zones at the 95% confidence interval. Zinc values were four orders of magnitude and Cu values three to four orders of magnitude below US EPA guideline limits. The EPA does not have guidelines for Mn, but Mn levels were lower than reported typical natural values for a nearby area. Therefore, metal contents were not high enough to be of concern. Taken together, these results were interpreted to indicate that the low-intensity camping activities that occur at Strawberry Lake campground have not had a significant negative impact on the soils found there. Additional information on this study can be found in Tibor and Brevik (2013). Reference Tibor, M.A., and E.C. Brevik. 2013. Anthropogenic Impacts on Campsite Soils at Strawberry Lake, North Dakota. Soil Horizons 54: doi:10.2136/sh13-06-0016.

Color and 3D views of the Sierra Nevada mountains

NASA Technical Reports Server (NTRS)

2002-01-01

A stereo 'anaglyph' created using the nadir and 45.6-degree forward-viewing cameras provides a three-dimensional view of the scene when viewed with red/blue glasses. The red filter should be placed over your left eye. To facilitate the stereo viewing, the images have been oriented with north toward the left. Some prominent features are Mono Lake, in the center of the image; Walker Lake, to its left; and Lake Tahoe, near the lower left. This view of the Sierra Nevadas includes Yosemite, Kings Canyon, and Sequoia National Parks. Mount Whitney, the highest peak in the contiguous 48 states (elev. 14,495 feet), is visible near the righthand edge. Above it (to the east), the Owens Valley shows up prominently between the Sierra Nevada and Inyo ranges. Precipitation falling as rain or snow on the Sierras feeds numerous rivers flowing southwestward into the San Joaquin Valley. The abundant fields of this productive agricultural area can be seen along the lower right; a large number of reservoirs that supply water for crop irrigation are apparent in the western foothills of the Sierras. Urban areas in the valley appear as gray patches; among the California cities that are visible are Fresno, Merced, and Modesto.

Evaporation from Lake Mead, Arizona and Nevada, 1997-99

USGS Publications Warehouse

Westenburg, Craig L.; DeMeo, Guy A.; Tanko, Daron J.

2006-01-01

Lake Mead is one of a series of large Colorado River reservoirs operated and maintained by the Bureau of Reclamation. The Colorado River system of reservoirs and diversions is an important source of water for millions of people in seven Western States and Mexico. The U.S. Geological Survey, in cooperation with the Bureau of Reclamation, conducted a study from 1997 to 1999 to estimate evaporation from Lake Mead. For this study, micrometeorological and hydrologic data were collected continually from instrumented platforms deployed at four locations on the lake, open-water areas of Boulder Basin, Virgin Basin, and Overton Arm and a protected cove in Boulder Basin. Data collected at the platforms were used to estimate Lake Mead evaporation by solving an energy-budget equation. The average annual evaporation rate at open-water stations from January 1998 to December 1999 was 7.5 feet. Because the spatial variation of monthly and annual evaporation rates was minimal for the open-water stations, a single open-water station in Boulder Basin would provide data that are adequate to estimate evaporation from Lake Mead.

Tsunami-generated boulder ridges in Lake Tahoe, California-Nevada

USGS Publications Warehouse

Moore, J.G.; Schweickert, R.A.; Robinson, J.E.; Lahren, M.M.; Kitts, Christopher A.

2006-01-01

An array of east-trending ridges 1-2 m high and up to 2 km long occurs on the Tahoe City shelf, a submerged wave-cut bench <15 m deep in the northwest sector of the lake. The shelf is just north of the amphitheater of the giant subaqueous 10 km3 McKinney Bay landslide, which originated on the west wall of Lake Tahoe. Images from a submersible camera show that the ridges are composed of loose piles of boulders and cobbles that lie directly on poorly consolidated, fine-bedded lake beds deposited in an ancestral Lake Tahoe. Dredge hauls from landslide distal blocks, as well as from the walls of the re-entrant of the landslide, recovered similar lake sediments. The McKinney Bay landslide generated strong currents, which rearranged previous glacial-derived debris into giant ripples creating the boulder ridges. The uncollapsed part of the sediment bench, including the Tahoe City shelf, poses a hazard because it may fail again, producing a landslide and damaging waves. ?? 2006 Geological Society of America.

Microbial and biogeochernical processes Soda Lake, Nevada

USGS Publications Warehouse

Oremland, R.S.; Cloern, J.E.; Sofer, Z.; Smith, R.L.; Culbertson, C.W.; Zehr, J.; Miller, L.; Cole, B.; Harvey, R.; Iversen, N.; Klug, M.; Des Marais, D J; Rau, G.

1988-01-01

Meromictic, alkaline lakes represent modern-day analogues of lacustrine source rock depositional environments. In order to further our understanding of how these lakes function in terms of limnological and biogeochemical processes, we have conducted an interdisciplinary study of Big Soda Lake. Annual mixolimnion productivity (ca. 500 g m-2) is dominated by a winter diatom bloom (60% of annual) caused by upward transport of ammonia to the epilimnion. The remainder of productivity is attributable to chemoautotrophs (30%) and photosynthetic bacteria (10%) present at the oxic -anoxic interface from May to November. Studies of bacterial heterotrophy and particulate fluxes in the water column indicate that about 90% of annual productivity is remineralized in the mixolimnion, primarily by fermentative bacteria. However, high rates of sulphate reduction (9-29 mmol m-2 yr-1) occur in the monimolimnion waters, which could remineralize most (if not all) of the primary productivity. This discrepancy has not as yet been fully explained. Low rates of methanogenesis also occur in the monimolimnion waters and sediments. Most of the methane is consumed by anaerobic methane oxidation occurring in the monimolimnion water column. Other bacterial processes occurring in the lake are also discussed. Preliminary studies have been made on the organic geochemistry of the monimolimnion sediments. Carbon-14-dating indicates a lower depositional rate prior to meromixis and a downcore enrichment in 13C of organic carbon and chlorophyll derivatives. Hydrous pyrolysis experiments indicate that the sediment organic matter is almost entirely derived from the water column with little or no contribution from terrestrial sources. The significance of the organics released by hydrous pyrolysis is discussed.

Modeling salinization and recovery of road salt-impacted lakes in temperate regions based on long-term monitoring of Lake George, New York (USA) and its drainage basin.

PubMed

Sutherland, J W; Norton, S A; Short, J W; Navitsky, C

2018-05-08

Road salt mitigates winter highway icing but accumulates in watershed soils and receiving waters, affecting soil chemistry and physical, biological, and ecological processes. Despite efforts to reduce salt loading in watersheds, accumulated cations and Cl - continue to impact tributaries and lakes, and the recovery process is not well understood. Lake George, New York (USA) is typical of many temperate lakes at risk for elevated Cl - concentrations from winter deicing; the lake salt concentration increased by ~3.4% year -1 since 1980. Here, we evaluated the ionic composition in Finkle Brook, a major watershed draining to Lake George, studied intermittently since 1970 and typical of other salt-impacted Lake George tributaries. Salt loading in the Lake George basin since the 1940s displaced cations from exchange sites in basin soils; these desorbed cations follow a simple ion-exchange model, with lower sodium and higher calcium, magnesium and potassium fluxes in runoff. Reduced salt application in the Finkle Brook watershed during the low-snow winter of 2015-2016 led to a 30-40% decline of Cl - and base cations in the tributary, implying a Cl - soil half-life of 1-2 years. We developed a conceptual model that describes cation behavior in runoff from a watershed that received road salt loading over a long period of time, and then recovery following reduced salt loading. Next, we developed a dynamic model estimating time to steady-state for Cl - in Lake George with road salt loading starting in 1940, calibrating the model with tributary runoff and lake chemistry data from 1970 and 1980, respectively, and forecasting Cl - concentrations in Lake George based on various scenarios of salt loading and soil retention of Cl - . Our Lake George models are readily adaptable to other temperate lakes with drainage basins where road salt is applied during freezing conditions and paved roads cover a portion of the watershed. Copyright © 2018 Elsevier B.V. All rights reserved.

Lake Tahoe Ca-Nv USA to Climate Change

NASA Astrophysics Data System (ADS)

Sahoo, G. B.; Schladow, S. G.; Reuter, J. E.; Coats, R. N.

2011-12-01

Observational studies indicate that climate at Lake Tahoe (CA-NV) basin is changing at faster rate. The impact of climate change on the lake was investigated using a suite of models and bias-corrected downscaled climate dataset generated from global circulation models. Our results indicate an increase of air temperature, a shift of snow to rainfall, a decrease of wind speed, and an onset of earlier snowmelt during the 21st Century. Combined, these changes could affect lake dynamics, ecosystems, water supply, and the winter recreational sport industry. The lake may fail to mix completely by the middle of this Century due to lake warming. Under this condition bottom dissolved oxygen would not be replenished leading to the significant release of bio-stimulatory ammonium-nitrogen and soluble phosphorus from the sediment. Both these nutrients are known to cause increased algal growth in the lake and would likely result in major changes to the lake's water quality and food web. Lake warming also increases water loss through evaporation, resulting in less available water for downstream domestic supply, agriculture, and recreation. Population growth and increased human demand for water will compound severity of problems in water quantity and quality. Thus, watershed planning and management should assess vulnerability to climatic variations through the application of basin-wide hydro-climatology, watershed soils, and lake response models to (1) improve drought, flood, and forest-fire forecasting, (2) assess hydrological trends, (3) estimate the potential effects of climate change on surface runoff and pollutant loads, and (4) evaluate response from various adaptation strategies.

Tracing long-term vadose zone processes at the Nevada Test Site, USA

PubMed Central

Hunt, James R.; Tompson, Andrew F. B.

2010-01-01

The nuclear weapons testing programme of the USA has released radionuclides to the subsurface at the Nevada Test Site. One of these tests has been used to study the hydrological transport of radionuclides for over 25 years in groundwater and the deep unsaturated zone. Ten years after the weapon’s test, a 16 year groundwater pumping experiment was initiated to study the mobility of radionuclides from that test in an alluvial aquifer. The continuously pumped groundwater was released into an unlined ditch where some of the water infiltrated into the 200 m deep vadose zone. The pumped groundwater had well-characterized tritium activities that were utilized to trace water migration in the shallow and deep vadose zones. Within the near-surface vadose zone, tritium levels in the soil water are modelled by a simple one-dimensional, analytical wetting front model. In the case of the near-surface soils at the Cambric Ditch experimental site, water flow and salt accumulation appear to be dominated by rooted vegetation, a mechanism not included within the wetting front model. Simulation results from a two-dimensional vadose groundwater flow model illustrate the dominance of vertical flow in the vadose zone and the recharge of the aquifer with the pumped groundwater. The long-time series of hydrological data provides opportunities to understand contaminant transport processes better in the vadose zone with an appropriate level of modelling. PMID:21785525

Ecology, biodiversity, management, and restoration of aspen in the Sierra Nevada

Treesearch

Wayne D. Shepperd; Paul C. Rogers; David Burton; Dale L. Bartos

2006-01-01

This report was commissioned by the USDA Forest Service Lake Tahoe Basin Management Unit to synthesize existing information on the ecology and management of aspen (Populus tremuloides) in the Sierra Nevada of California and surrounding environs. It summarizes available information on aspen throughout North America from published literature, internal...

Neodymium Isotope Variations in Late Quaternary Carbonate Lake Sediments, Owens Valley, Eastern California.

NASA Astrophysics Data System (ADS)

Minervini, J. M.; Stewart, B. W.

2001-12-01

Owens Lake is situated in a mostly-closed basin fed by water and sediments derived primarily from the eastern Sierra Nevada range. Chemical and sedimentological variations in USGS Owens Lake Core OL-92, which extends back 800 ka, have been shown to be sensitive tracers of Great Basin paleoclimate. Here we report preliminary neodymium (Nd) isotope data from core OL-92 to investigate sediment provenance, the chemical behavior of rare earth elements (REE) in non-marine systems, and possible climate-related shifts in weathering patterns of the eastern Sierra Nevada during the last glacial-interglacial transition. Neodymium isotopic analyses were carried out on the carbonate fraction of sediment samples ranging in age from 16.8 to 6.9 ka from Owens Lake core OL-92. Samples were treated with ammonium acetate to remove exchangeable cations from coexisting silicate material, and subsequently leached with 8% acetic acid to dissolve carbonate minerals. Based on the mass of sediment leached with acetic acid, the fraction of carbonate (relative to clastic silicate material) increases from 6.6 to 66.5% over the 10 ka period represented by these samples. This increase in carbonate reflects desiccation of the Owens Lake basin; as streamwater flow is reduced, the lake spends a greater proportion of its time saturated in carbonate minerals, and clastic input might also be reduced. Concentrations of Nd in Owens Lake carbonate range from 7 to 170 ppm, values that are 2-1000 times higher than marine planktonic foraminifera (e.g., Vance and Burton, 1999, EPSL 173, 365). In general, high concentrations of Nd in Owens Lake carbonate are associated with older sediment samples with lower carbonate fractions. The decrease in Nd concentration over this time period could be a result of extraction of Nd from lake waters by precipitation of carbonate as desiccation proceeded. Epsilon-Nd values of Owens Lake carbonate range from -5.3 to -6.5, and are consistent with eastern Sierra Nevada

An overview of the Southern Nevada Agency Partnership science and research synthesis: Chapter 1 in The Southern Nevada Agency Partnership science and research synthesis: science to support land management in southern Nevada

USGS Publications Warehouse

Chambers, Jeanne C.; Brooks, Matthew L.; Turner, Kent; Raish, Carol B.; Ostoja, Steven M.

2013-01-01

Maintaining and restoring the diverse ecosystems and resources that occur in southern Nevada in the face of rapid socio-economic and ecological change presents numerous challenged to Federal land managers. Rapid population growth since the 1980s, the land uses associated with that growth, and the interactions of those uses with the generally dry and highly variable climate result in numerous stresses to ecosystems, species, and cultural resource. In addition, climate models predict that the rate of temperature increase and, thus, changes in ecological processes, will be highest for ecosystems like the Mojave Desert. The Southern Nevada Agency Partnership (SNAP; http:www.SNAP.gov) was established in 1999 to address common issues pertaining to public lands in southern Nevada. Partners include the Bureau of Land Management, National Park Service, U.S. Fish and Wildlife Service, and USDA Forest Service and they work with each other, the local community, and other partners. SNAP agencies manage more than seven million acres of public lands in southern Nevada (95% of the land area). Federal land includes two national recreation areas, two national conservation area, four national wildlife refuges, 18 congressionally designated wilderness areas, five wilderness study areas, and 22 areas of critical environmental concern. The partnership's activities are mainly centered in Southern Nevada's Clark County (fig. 1.1), but lands managed by SNAP partner agencies also include portions of Lake Mead National Recreation Area in Mohave County, Arizona, U.S. Fish and Wildlife Service, and USDA Forest Service-managed lands in Lincoln and Nye Counties, Nevada, and all lands and activities managed by the Southern Nevada District Office of the Bureau of Land Management. These lands encompass nine distinct ecosystem types (fig. 1.2), support multiple species of management concern an 17 listed species, and are rich in cultural and historic resource. This introductory executive summary

Airborne lidar detection and mapping of invasive lake trout in Yellowstone Lake.

PubMed

Roddewig, Michael R; Churnside, James H; Hauer, F Richard; Williams, Jacob; Bigelow, Patricia E; Koel, Todd M; Shaw, Joseph A

2018-05-20

The use of airborne lidar to survey fisheries has not yet been extensively applied in freshwater environments. In this study, we investigated the applicability of this technology to identify invasive lake trout (Salvelinus namaycush) in Yellowstone Lake, Yellowstone National Park, USA. Results of experimental trials conducted in 2004 and in 2015-16 provided lidar data that identified groups of fish coherent with current knowledge and models of lake trout spawning sites, and one identified site was later confirmed to have lake trout.

Fish tag recovery from Anaho Island nesting colony, Pyramid Lake, Nevada

USGS Publications Warehouse

Scoppettone, G. Gary; Fabes, Mark C.; Rissler, Peter H.; Withers, Donna

2016-01-06

In 2001, tags applied to the federally endangered species cui-ui (Chasmistes cujus) to study their population dynamics were discovered strewn throughout the American White Pelican (Pelecanus erythrorhynchos) nesting colony on Anaho Island, Pyramid Lake, Nevada. Cui-ui are endemic to Pyramid Lake, and Anaho Island harbors one of North America’s largest nesting colonies of American White Pelican. Cui-ui are consumed by pelicans during the fish’s spring migration into the Truckee River to reproduce. The predatory success of pelican has been validated by determining the odds of finding a tag from a predated cui-ui within the Anaho Island nesting colony. It is unknown how many cui-ui tags are eliminated by birds before arrival to the colony versus how many are brought to the colony but never recovered. The focus of this study was to improve the estimate of the chances of collecting a tag from a predated adult cui-ui in the pelican nesting colony by feeding dead tagged Lahontan cutthroat trout (Oncorhynchus clarkii henshawi) and common carp (Cyprinus carpio) to pelican and subsequently searching for these tags within the colony. We also randomly deployed 1,000 dispersal tags throughout the nesting colony, searching for these after one and two breeding seasons. After adding 1,027 fed fish to 547 previously fed fish, we estimated 5.3 percent of the tagged cui-ui taken by pelican were recovered during tag searches. A study of dispersal tags randomly deployed within the pelican nesting colony showed that 51.5 percent would be expected to be recovered after at least one breeding season after being deployed. Results of our studies indicate that more than 90 percent of tags from adult cui-ui are eliminated by birds outside the pelican nesting colony. Tags recovered from other species and the site at which they were tagged are also reported. Most notable were recovered Lahontan cutthroat trout tags, which were the highest in number, but their proximity to double

Recent lake ice-out phenology within and among lake districts of Alaska, U.S.A.

USGS Publications Warehouse

Arp, Christopher D.; Jones, Benjamin M.; Grosse, Guido

2013-01-01

The timing of ice-out in high latitudes is a fundamental threshold for lake ecosystems and an indicator of climate change. In lake-rich regions, the loss of ice cover also plays a key role in landscape and climatic processes. Thus, there is a need to understand lake ice phenology at multiple scales. In this study, we observed ice-out timing on 55 large lakes in 11 lake districts across Alaska from 2007 to 2012 using satellite imagery. Sensor networks in two lake districts validated satellite observations and provided comparison with smaller lakes. Over this 6 yr period, the mean lake ice-out for all lakes was 27 May and ranged from 07 May in Kenai to 06 July in Arctic Coastal Plain lake districts with relatively low inter-annual variability. Approximately 80% of the variation in ice-out timing was explained by the date of 0°C air temperature isotherm and lake area. Shoreline irregularity, watershed area, and river connectivity explained additional variation in some districts. Coherence in ice-out timing within the lakes of each district was consistently strong over this 6 yr period, ranging from r-values of 0.5 to 0.9. Inter-district analysis of coherence also showed synchronous ice-out patterns with the exception of the two arctic coastal districts where ice-out occurs later (June–July) and climatology is sea-ice influenced. These patterns of lake ice phenology provide a spatially extensive baseline describing short-term temporal variability, which will help decipher longer term trends in ice phenology and aid in representing the role of lake ice in land and climate models in northern landscapes.

Audiomagnetotelluric Data and Two-Dimensional Models from Spring, Snake, and Three Lakes Valleys, Nevada

USGS Publications Warehouse

McPhee, Darcy K.; Chuchel, Bruce A.; Pellerin, Louise

2007-01-01

Audiomagnetotelluric (AMT) data along thirteen profiles in Spring, Snake, and Three Lakes Valleys, and the corresponding two-dimensional (2-D) inverse models, are presented. The AMT method is a valuable tool for estimating the electrical resistivity of the Earth over depth ranges of a few meters to roughly one kilometer. It is important for revealing subsurface structure and stratigraphy within the Basin and Range province of eastern Nevada that can be used to define the geohydrologic framework of the region. We collected AMT data using the Geometrics StrataGem EH4 system. Profiles were 1.2 to 4.6 km in length with station spacing of 100-400 m. Data were recorded in a coordinate system parallel to and perpendicular to the assumed regional geologic strike direction. We show station locations, sounding curves of apparent resistivity, phase, and coherency, and 2-D models. The 2-D inverse models are computed from the transverse electric (TE), transverse magnetic (TM), and TE+TM mode data using the conjugate gradient, finite-difference method of Rodi and Mackie (2001). Preliminary interpretation of these models defines the structural framework of the basins and the resistivity contrasts between alluvial basin-fill, volcanic units, and carbonate/clastic rocks.

Fuel deposition rates of montane and subalpine conifers in the central Sierra Nevada, California, USA

USGS Publications Warehouse

van Wagtendonk, J.W.; Moore, P.E.

2010-01-01

Fire managers and researchers need information on fuel deposition rates to estimate future changes in fuel bed characteristics, determine when forests transition to another fire behavior fuel model, estimate future changes in fuel bed characteristics, and parameterize and validate ecosystem process models. This information is lacking for many ecosystems including the Sierra Nevada in California, USA. We investigated fuel deposition rates and stand characteristics of seven montane and four subalpine conifers in the Sierra Nevada. We collected foliage, miscellaneous bark and crown fragments, cones, and woody fuel classes from four replicate plots each in four stem diameter size classes for each species, for a total of 176 sampling sites. We used these data to develop predictive equations for each fuel class and diameter size class of each species based on stem and crown characteristics. There were consistent species and diameter class differences in the annual amount of foliage and fragments deposited. Foliage deposition rates ranged from just over 50 g m-2 year-1 in small diameter mountain hemlock stands to ???300 g m-2 year-1 for the three largest diameter classes of giant sequoia. The deposition rate for most woody fuel classes increased from the smallest diameter class stands to the largest diameter class stands. Woody fuel deposition rates varied among species as well. The rates for the smallest woody fuels ranged from 0.8 g m-2 year-1 for small diameter stands of Jeffrey pine to 126.9 g m-2 year-1 for very large diameter stands of mountain hemlock. Crown height and live crown ratio were the best predictors of fuel deposition rates for most fuel classes and species. Both characteristics reflect the amount of crown biomass including foliage and woody fuels. Relationships established in this study allow predictions of fuel loads to be made on a stand basis for each of these species under current and possible future conditions. These predictions can be used to

Integration of genotoxicity and population genetic analyses in kangaroo rats (Dipodomys merriami) exposed to radionuclide contamination at the Nevada Test Site, USA

USGS Publications Warehouse

Theodorakis, Christopher W.; Bickham, John W.; Lamb, Trip; Medica, Philip A.; Lyne, T. Barrett

2001-01-01

We examined effects of radionuclide exposure at two atomic blast sites on kangaroo rats (Dipodomys merriami) at the Nevada Test Site, Nevada, USA, using genotoxicity and population genetic analyses. We assessed chromosome damage by micronucleus and flow cytometric assays and genetic variation by randomly amplified polymorphic DNA (RAPD) and mitochondrial DNA (mtDNA) analyses. The RAPD analysis showed no population structure, but mtDNA exhibited differentiation among and within populations. Genotoxicity effects were not observed when all individuals were analyzed. However, individuals with mtDNA haplotypes unique to the contaminated sites had greater chromosomal damage than contaminated-site individuals with haplotypes shared with reference sites. When interpopulation comparisons used individuals with unique haplotypes, one contaminated site had greater levels of chromosome damage than one or both of the reference sites. We hypothesize that shared-haplotype individuals are potential migrants and that unique-haplotype individuals are potential long-term residents. A parsimony approach was used to estimate the minimum number of migration events necessary to explain the haplotype distributions on a phylogenetic tree. The observed predominance of migration events into the contaminated sites supported our migration hypothesis. We conclude the atomic blast sites are ecological sinks and that immigration masks the genotoxic effects of radiation on the resident populations.

First record of trypanosomes from the blood of sculpins (Cottus ricei and C. cognatus) from Lake Superior, WI, USA

USGS Publications Warehouse

Pronina, Svetlana V.; Pronin, Nikolai M.; Selgeby, Jim H.

1999-01-01

During parasitological research of fishes in Lake Superior (USA) in August-September 1994, infection with trypanosomes of the blood of sculpins (Cottus ricei and C. cognatus) was recorded for the first time. The descriptions of three morphological groups of the genus Trypanosoma: T. sp. I, found in blood of C. ricei, T. sp. II and T. sp. III from blood of C. cognatus, have been provided.

Recent geologic development of Lake Michigan (U.S.A.)

USGS Publications Warehouse

Gross, D.L.; Cahill, R.A.

1983-01-01

The stresses placed on Lake Michigan since the advent of industrialization require knowledge of the sedimentology of the whole lake in order to make informed decisions for environmental planning. Sediment accumulation rates are low: areas of the lake receiving the most sediment average only 1 mm a-1; deep-water basins average 0.1 to 0.5 mm a-1; and large areas are not receiving any sediment. Sediment was deposited rapidly (typically 5 mm a-1), in the form of rock flour, during the deglaciation of both Lake Michigan and Lake Superior Basins. Then the rate of accumulation decreased by 80-90% and has remained relatively constant since final deglaciation. Because active sedimentation occurs mostly in the deep water areas of the lake, the sediment remains undisturbed and contains a record of the chemical history of the lake. ?? 1983 Dr W. Junk Publishers.

MERCURY CONCENTRATIONS IN SKELETAL MUSCLE OF FISH FROM LAKE MEAD, USA, RELATED TO FISH SIZE, CONDITION, TROPHIC LEVEL, LOCATION, AND CONSUMPTION RISK

EPA Science Inventory

In this first large-scale study of mercury (Hg) in Lake Mead, USA, the nation's largest man-
made reservoir, total-Hg concentrations were determined in the skeletal muscle of 339 fish collected during the Fall of 1998 and the Spring of 1999. Five species of fish representing ...

Near-Surface Geophysical Character of a Holocene Fault Carrying Geothermal Flow Near Pyramid Lake, Nevada

NASA Astrophysics Data System (ADS)

Dudley, C.; Dorsey, A.; Louie, J. N.; Schwering, P. C.; Pullammanappallil, S.

2012-12-01

Lines of calcium carbonate tufa columns mark recent faults that cut 11 ka Lake Lahontan sediments at Astor Pass, north of Pyramid Lake, Nevada. Throughout the Great Basin, faults appear to control the location of geothermal resources, providing pathways for fluid migration. Reservoir-depth (greater than 1 km) seismic imaging at Astor Pass shows a fault that projects to one of the lines of tufa columns at the surface. The presence of the tufa deposits suggests this fault carried warm geothermal waters through the lakebed clay sediments in recent time. The warm fluids deposited the tufa when they hit cold Lake Lahontan water at the lakebed. Lake Lahontan covered this location to a depth of at least 60 m at 11 ka. In collaboration with the Pyramid Lake Paiute Tribe, an Applied Geophysics class at UNR investigated the near-surface geophysical characteristics of this fault. The survey comprises near-surface seismic reflection and refraction, nine near-surface refraction microtremor (SeisOpt® ReMi™) arrays, nine near-surface direct-current resistivity soundings, magnetic surveys, and gravity surveys at and near the tufa columns. The refraction microtremor results show shear velocities near tufa and faults to be marginally lower, compared to Vs away from the faults. Overall, the 30-m depth-averaged shear velocities are low, less than 300 m/s, consistent with the lakebed clay deposits. These results show no indication of any fast (> 500 m/s) tufa below the surface at or near the tufa columns. Vs30 averages were 274 ± 13 m/s on the fault, 287 ± 2 m/s at 150 m east of the fault, and 290 ± 15 m/s at 150 m west of the fault. The P-velocity refraction optimization results also show no indication of high-velocity tufa buried below the surface in the Lahontan sediments, reinforcing the idea that all tufa was deposited above the lakebed surface. The seismic results provide a negative test of the hypothesis that deposition of the lakebeds in the Quaternary buried and

Evidence of Regional Warming during the 20th Century in Alpine and Subalpine Lakes in the Western United States

NASA Astrophysics Data System (ADS)

Porinchu, D.; Reinemann, S.; Potito, A.; Moser, K.; MacDonald, G.; Munroe, J.; Mark, B.; Box, J.

2007-12-01

Subfossil midge analyses have been used to develop high-resolution (sub-decadal) reconstructions of 20th century temperature change in the Sierra Nevada, CA with success. Expansion of this earlier work to additional sites in the western United States suggests that a widespread increase in lake water temperatures has occurred in this region during the late 20th and early 21st centuries. Inference models for summer surface water temperature (SSWT) were developed combining midge abundance data from 56 lakes in the eastern Sierra Nevada, California, with subfossil midge remains from the Uinta Mountains, UT. The newly merged Sierra Nevada-Uinta Mountains calibration set contains a greater diversity of chironomid assemblages and spans a wider SSWT range than the previously published Sierra Nevada calibration set. The lakes in the merged calibration set spanned elevation, depth, and SSWT temperature ranges of 900 m, 12.7 m, and 11.3 °C, respectively. A robust inference model for SSWT (3-component WA-PLS), based on 90 lakes, had a high coefficient of determination (r2jack = 0.66) and a low RMSEP (1.4 °C). The midge-based SSWT inference model was applied to subfossil chironomid remains extracted from well-dated sediment sequences recovered from alpine and subalpine lakes in the Sierra Nevada, CA, Snake Range, NV and Uinta Mountains, UT. A close correspondence exists between the chironomid-inferred temperature profiles for the 20th and 21st centuries and mean July or summer temperatures measured at nearby meteorological stations. Application of this midge-based SSWT inference model to other intact, late Quaternary sedimentary sequences found in subalpine and alpine lakes in the Great Basin will help resolve the impact of late Quaternary and recent climate change in this region, improve our understanding of regional climate and aquatic ecosystem variability, and can be used to monitor the effects of climate change on aquatic ecosystems and establish 'baseline' conditions

Charcoal deposition and redeposition in Elk Lake, Minnesota, USA

USGS Publications Warehouse

Platt, Bradbury J.

1996-01-01

Sedimentary charcoal, diatom and phytolith records of the past 1500 years at Elk Lake, Minnesota, in combination with sediment trap studies and a transect of surface sediment samples, document the mechanisms by which previously deposited charcoal is redeposited and finally buried in this lake. The frequent correspondence of high diatom concentrations and peaks of phytolith and charcoal fragments suggest that currents and turbulence related to lake circulation are responsible for winnowing charcoal and phytoliths from shallow water depositional sites to deeper areas of the lake. High diatom concentrations in the record relate to increased nutrient fluxes also supplied by circulation. Despite the fact that the watershed and area around Elk Lake has not been burned since AD 1922, charcoal continues to reach the profundal zone from littoral source areas in Elk Lake. The variable redeposition of within-lake charcoal requires evaluation before fire-history records can be related to global, regional or even local fire events.

Hot springs of the central Sierra Nevada, California

USGS Publications Warehouse

Mariner, R.H.; Presser, T.S.; Evans, William C.

1977-01-01

Thermal springs of the central Sierra Nevada issue dilute to slightly saline sodium chloride, sodium bicarbonate, or sodium mixed-anion waters ranging in pH from 6.4 to 9.3. The solubility of chalcedony appears to control the silica concentration in most of the spring waters. Fales Hot Springs may be associated with a higher temperature aquifer, 150 degrees Celsius or more, in which quartz is controlling the silica concentration. Carbon dioxide is the predominant gas escaping from Fales Hot Springs, the unnamed hot spring on the south side of Mono Lake, and the two thermal springs near Bridgeport. Most of the other thermal springs issue small amounts of gas consisting principally of nitrogen. Methane is the major component of the gas escaping from the unnamed spring on Paoha Island in Mono Lake. The deuterium and oxygen isotopic composition of most of the thermal waters are those expected for local meteoric water which has undergone minor water-rock reaction. The only exceptions are the hot spring on Paoha Island in Mono Lake and perhaps the unnamed warm spring (south side of Mono Lake) which issues mixtures of thermal water and saline lake water. (Woodard-USGS)

Lake Tahoe watershed assessment: volume II.

Treesearch

Dennis D. Murphy; Christopher M. Knopp

2000-01-01

This watershed assessment of the Lake Tahoe basin in northern California and Nevada is the first attempt to collate, synthesize, and interpret available scientific information with a comprehensive view toward management and policy outcomes. The seven-chapter report presents new and existing information in subject areas pertinent to policy development and land and...

Lake Tahoe watershed assessment: volume I

Treesearch

Dennis D. Murphy; Christopher M. Knopp

2000-01-01

This watershed assessment of the Lake Tahoe basin in northern California and Nevada is the first attempt to collate, synthesize, and interpret available scientific information with a comprehensive view toward management and policy outcomes. The seven-chapter report presents new and existing information in subject areas pertinent to policy development and land and...

Seismic architecture and lithofacies of turbidites in Lake Mead (Arizona and Nevada, U.S.A.), an analogue for topographically complex basins

USGS Publications Warehouse

Twichell, D.C.; Cross, V.A.; Hanson, A.D.; Buck, B.J.; Zybala, J.G.; Rudin, M.J.

2005-01-01

Turbidites, which have accumulated in Lake Mead since completion of the Hoover Dam in 1935, have been mapped using high-resolution seismic and coring techniques. This lake is an exceptional natural laboratory for studying fine-grained turbidite systems in complex topographic settings. The lake comprises four relatively broad basins separated by narrow canyons, and turbidity currents run the full length of the lake. The mean grain size of turbidites is mostly coarse silt, and the sand content decreases from 11-30% in beds in the easternmost basin nearest the source to 3-14% in the central basins to 1-2% in the most distal basin. Regionally, the seismic amplitude mimics the core results and decreases away from the source. The facies and morphology of the sediment surface varies between basins and suggests a regional progression from higher-energy and possibly channelized flows in the easternmost basin to unchannelized flows in the central two basins to unchannelized flows that are ponded by the Hoover Dam in the westernmost basin. At the local scale, turbidites are nearly flat-lying in the central two basins, but here the morphology of the basin walls strongly affects the distribution of facies. One of the two basins is relatively narrow, and in sinuous sections reflection amplitude increases toward the outsides of meanders. Where a narrow canyon debouches into a broad basin, reflection amplitude decreases radially away from the canyon mouth and forms a fan-like deposit. The fine-grained nature of the turbidites in the most distal basin and the fact that reflections drape the underlying pre-impoundment surface suggest ponding here. The progression from ponding in the most distal basin to possibly channelized flows in the most proximal basin shows in plan view a progression similar to the stratigraphic progression documented in several minibasins in the Gulf of Mexico. Copyright ?? 2005, SEPM (Society for Sedimentary Geology).

Some New Constraints On The Stratigraphic And Structural Setting Of The Soda Lake Geothermal Field, Churchill County, Nevada - McLACHLAN, Holly S. and FAULDS, James E., Nevada Bureau of Mines and Geology, University of Nevada, Reno, NV 89557

NASA Astrophysics Data System (ADS)

McLachlan, H. S.

2012-12-01

Our research group is currently conducting a regional survey to identify favorable structural settings of producing and prospective geothermal fields in the Great Basin. The Soda Lake geothermal field - one of the oldest consistently producing fields in this study region - is located in west-central Nevada near the heart of the Carson Sink. Producing and prospective geothermal fields in the surrounding highlands are hosted in 1) fault termination zones (Desert Queen), 2) accommodation zones (Brady's Hot Springs) and 3) fault step-overs (Desert Peak). However, the structural setting is challenging to identify at the Soda Lake field, because it lies in the central part of a large basin with no nearby bedrock exposures. The well field at Soda Lake is centered ~3.5 km NNE of the Holocene Soda Lake maar, from which it takes its name. The geothermal field was identified serendipitously during the drilling of an irrigation survey well in the early 20th century. Modern exploratory drilling at the field began in the mid-1970s and has continued sporadically to the present. There are currently more than 28 500+ m wells at and near the production site. The exceptional drilling density at Soda Lake allows for comparatively reliable correlation of stratigraphy in the subsurface below the feature-poor Carson Sink. Stratigraphy in the Soda Lake geothermal area is relatively "layer cake" at the scale of the well field. Unconsolidated sediments extend more than 1000 m below surface. The upper few hundred meters are composed of fluvial and lacustrine sediments derived from Sierran batholith source rocks. The deeper basin fill derives from more proximal mafic to felsic Miocene volcanic rocks along the basin margins. At ~450-650 m depth, basin sediments are interrupted by a 5.11 Ma trachytic basalt of restricted lateral extent and variable thickness. Most wells intercept ~50-250 m of fine lacustrine sediments below this basalt body before intercepting the basin floor. Basin floor rocks

Physical controls on total and methylmercury concentrations in streams and lakes of the northeastern USA

USGS Publications Warehouse

Shanley, J.B.; Kamman, N.C.; Clair, T.A.; Chalmers, A.

2005-01-01

The physical factors controlling total mercury (HgT) and methylmercury (MeHg) concentrations in lakes and streams of northeastern USA were assessed in a regional data set containing 693 HgT and 385 corresponding MeHg concentrations in surface waters. Multiple regression models using watershed characteristics and climatic variables explained 38% or less of the variance in HgT and MeHg. Land cover percentages and soil permeability generally provided modest predictive power. Percent wetlands alone explained 19% of the variance in MeHg in streams at low-flow, and it was the only significant (p < 0.02) predictor for MeHg in lakes, albeit explaining only 7% of the variance. When stream discharge was added as a variable it became the dominant predictor for HgT in streams, improving the model r 2 from 0.19 to 0.38. Stream discharge improved the MeHg model more modestly, from r 2 of 0.25 to 0.33. Methylation efficiency (MeHg/HgT) was modeled well (r 2 of 0.78) when a seasonal term was incorporated (sine wave with annual period). Physical models explained 18% of the variance in fish Hg concentrations in 134 lakes and 55% in 20 reservoirs. Our results highlight the important role of seasonality and short-term hydrologic changes to the delivery of Hg to water bodies. ?? 2005 Springer Science+Business Media, Inc.

Spatial decorrelation stretch of annual (2003-2014) Daymet precipitation summaries on a 1-km grid for California, Nevada, Arizona, and Utah.

PubMed

Ch Miliaresis, George

2016-06-01

A method is presented for elevation (H) and spatial position (X, Y) decorrelation stretch of annual precipitation summaries on a 1-km grid for SW USA for the period 2003 to 2014. Multiple linear regression analysis of the first and second principal component (PC) quantifies the variance in the multi-temporal precipitation imagery that is explained by X, Y, and elevation (h). The multi-temporal dataset is reconstructed from the PC1 and PC2 residual images and the later PCs by taking into account the variance that is not related to X, Y, and h. Clustering of the reconstructed precipitation dataset allowed the definition of positive (for example, in Sierra Nevada, Salt Lake City) and negative (for example, in San Joaquin Valley, Nevada, Colorado Plateau) precipitation anomalies. The temporal and spatial patterns defined from the spatially standardized multi-temporal precipitation imagery provide a tool of comparison for regions in different geographic environments according to the deviation from the precipitation amount that they are expected to receive as function of X, Y, and h. Such a standardization allows the definition of less or more sensitive to climatic change regions and gives an insight in the spatial impact of atmospheric circulation that causes the annual precipitation.

Geology of the Ivanhoe Hg-Au district, northern Nevada: Influence of Miocene volcanism, lakes, and active faulting on epithermal mineralization

USGS Publications Warehouse

Wallace, A.R.

2003-01-01

The mercury-gold deposits of the Ivanhoe mining district in northern Nevada formed when middle Miocene rhyolitic volcanism and high-angle faulting disrupted a shallow lacustrine environment. Sinter and replacement mercury deposits formed at and near the paleosurface, and disseminated gold deposits and high-grade gold-silver veins formed beneath the hot spring deposits. The lacustrine environment provided abundant meteoric water; the rhyolites heated the water; and the faults, flow units, and lakebeds provided fluid pathways for the hydrothermal fluids. A shallow lake began to develop in the Ivanhoe area about 16.5 Ma. The lake progressively expanded and covered the entire area with fine-grained lacustrine sediments. Lacustrine sedimentation continued to at least 14.4 Ma, and periodic fluctuations in the size and extent of the lake may have been responses to both climate and nearby volcanism. The eruption of rhyolite and andesite flows and domes periodically disrupted the lacustrine environment and produced interfingered flows and lake sediments. The major pulse of rhyolitic volcanism took place between 15.16 ± 0.05 and 14.92 ± 0.05 Ma. High-angle faulting began in the basement about 15.2 Ma, penetrated to and disrupted the paleosurface after 15.10 ± 0.06 Ma, and largely ceased by 14.92 ± 0.05 Ma. Ground motion related to both faulting and volcanism created debris flows and soft-sediment deformation in the lakebeds. Mercury-gold mineralization was coeval with rhyolite volcanism and high-angle faulting, and it took place about 15.2 to 14.9 Ma. At and near the paleosurface, hydrothermal fluids migrated through tuffaceous sediments above relatively impermeable volcanic and Paleozoic units, creating chalcedonic, cinnabar-bearing replacement bodies and sinters. Disseminated gold was deposited in sedimentary and volcanic rocks beneath the mercury deposits, although the hydrologic path between the two ore types is unclear. Higher-grade gold-silver deposits formed in

Hg-contaminated terrestrial spiders pose a potential risk to songbirds at Caddo Lake (Texas/Louisiana, USA).

PubMed

Gann, Gretchen L; Powell, Cleveland H; Chumchal, Matthew M; Drenner, Ray W

2015-02-01

Methylmercury (MeHg) is an environmental contaminant that can have adverse effects on wildlife. Because MeHg is produced by bacteria in aquatic ecosystems, studies of MeHg contamination of food webs historically have focused on aquatic organisms. However, recent studies have shown that terrestrial organisms such as songbirds can be contaminated with MeHg by feeding on MeHg-contaminated spiders. In the present study, the authors examined the risk that MeHg-contaminated terrestrial long-jawed orb weaver spiders (Tetragnatha sp.) pose to songbirds at Caddo Lake (Texas/Louisiana, USA). Methylmercury concentrations in spiders were significantly different in river, wetland, and open-water habitats. The authors calculated spider-based wildlife values (the minimum spider MeHg concentrations causing physiologically significant doses in consumers) to assess exposure risks for arachnivorous birds. Methylmercury concentrations in spiders exceeded wildlife values for Carolina chickadee (Poecile carolinensis) nestlings, with the highest risk in the river habitat. The present study indicates that MeHg concentrations in terrestrial spiders vary with habitat and can pose a threat to small-bodied nestling birds that consume large amounts of spiders at Caddo Lake. This MeHg threat to songbirds may not be unique to Caddo Lake and may extend throughout the southeastern United States. © 2014 SETAC.

Emerald Lake Watershed study: Introduction and site description

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tonnessen, K.A.

1991-07-01

The Emerald Lake Watershed study was organized to investigate the effects of acidic deposition on high-elevation watersheds and surface waters of the Sierra Nevada, California. Some of the results of this comprehensive study of aquatic and terrestrial ecosystems at a small, headwater basin are presented in four papers in this series. The watershed study site is in Sequoia National Park, on the western slope of the Sierra Nevada. This glacial cirque is located in the upper Marble Fork of the Kaweah River. This 120-ha watershed ranges from Alta Peak (3,416 m) down to Emerald Lake (2,400 m). Most of themore » watershed surface area is exposed granite and granodiorite rocks, with limited coverage (about 20%) by thin, acidic soils. The hydrology of the basin is dominated by snowmelt runoff during March-June. Emerald Lake, a glacial tarn, is 2.72 ha in area, with a maximum depth of 10.5 m. Surface waters are poorly buffered and dominated by calcium and bicarbonate. Most of the yearly precipitation falls as dilute snow (pH5.2-5.4), with acidic rain storms sampled during May-October.« less

Mercury sedimentation in lakes in western Whatcom County, Washington, USA and its relation to local industrial and municipal atmospheric sources

USGS Publications Warehouse

Paulson, A.J.; Norton, D.

2008-01-01

Concentrations of mercury (Hg) were measured in six dated cores from four lakes in western Whatcom County, Washington, USA, that were at various bearings from a chlor-alkali plant, two municipal waste incinerators and a municipal sewage sludge incinerator. The importance of atmospheric emissions of Hg from these local municipal and industrial sources was evaluating by comparing the temporal trends in sedimentation of the lake cores with the emission history of each Hg species and by examining the geographical distribution of Hg sedimentation in relation to the region's primary wind pattern. Local municipal and industrial sources of atmospheric Hg were not responsible for the majority of the Hg in the upper layer of sediments of Whatcom County lakes because of (1) the significant enrichment of Hg in lake sediments prior to emissions of local industrial and municipal sources in 1964, (2) smaller increases in Hg concentrations occurred after 1964, (3) the similarity of maximum enrichments found in Whatcom County lakes to those in rural lakes around the world, (4) the inconsistency of the temporal trends in Hg sedimentation with the local emission history, and (5) the inconsistency of the geographic trends in Hg sedimentation with estimated deposition. Maximum enrichment ratios of Hg in lake sediments between 2 and 3 that are similar to rural areas in Alaska, Minnesota, and New England suggest that global sources of Hg were primarily responsible for increases of Hg in Whatcom County lakes beginning about 1900. ?? 2007 GovernmentEmployee: U.S. Government, Department of Interior, U.S. Geological Survey.

Usefulness of natural regions for lake management: Analysis of variation among lakes in northwestern Wisconsin, USA

NASA Astrophysics Data System (ADS)

Omernik, James M.; Rohm, Christina M.; Lillie, Richard A.; Mesner, Nancy

1991-03-01

A map of summer total phosphorus in lakes was compiled recently for a three-state area of the upper Midwest for purposes of identifying regional patterns of total phosphorus in lakes and attainable lake trophic state. Spatial patterns in total phosphorus from approximately 3000 lakes were studied in conjunction with maps of geographic characteristics that tend to affect phosphorus balance in lakes to identify regions of similarity in phosphorus concentrations in lakes or similarity in the mosaic of values as compared to adjacent areas. While degrees of relative homogeneity are apparent at many scales, the map was designed at a scale that would yield regions with sufficient homogeneity to be useful for lake management throughout the area. In this study, data from 210 lakes in a 1560-mi2 area in northwestern Wisconsin, sampled by the Wisconsin Department of Natural Resources in the spring of 1988 (subsequent to the compilation of the phosphorus map), were examined to: (1) substantiate the existence of the regions depicted on the map in northwest Wisconsin, (2) determine the nature and relative precision of the regional boundaries, (3) determine the relative importance of natural and anthropogenic watershed characteristics, lake types, lake area, and lake depth in explaining within-region differences in lake phosphorus, and (4) demonstrate how the regions might be used by local lake managers.

Compound maar crater and co-eruptive scoria cone in the Lunar Crater Volcanic Field (Nevada, USA)

NASA Astrophysics Data System (ADS)

Amin, Jamal; Valentine, Greg A.

2017-06-01

Bea's Crater (Lunar Crater Volcanic Field, Nevada, USA) consists of two coalesced maar craters with diameters of 440 m and 1050 m, combined with a co-eruptive scoria cone that straddles the northeast rim of the larger crater. The two craters and the cone form an alignment that parallels many local and regional structures such as normal faults, and is interpreted to represent the orientation of the feeder dyke near the surface. The maar formed among a dense cluster of scoria cones; the cone-cluster topography resulted in crater rim that has a variable elevation. These older cones are composed of variably welded agglomerate and scoria with differing competence that subsequently affected the shape of Bea's Crater. Tephra ring deposits associated with phreatomagmatic maar-forming eruptions are rich in basaltic lithics derived from < 250 m depth, with variable contents of deeper-seated ignimbrite lithic clasts, consistent with ejection from relatively shallow explosions although a diatreme might extend to deeper levels beneath the maar. Interbedding of deposits on the northeastern cone and in the tephra ring record variations in the magmatic volatile driven and phreatomagmatic eruption styles in both space and time along a feeder dike.

Tectonic evolution of Honey Lake basin, northeastern California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wagner, D.L.; Saucedo, G.J.; Grose, T.L.T.

New geologic mapping in northeastern California provides additional data on the age and tectonic evolution of the Honey Lake Basin. Rhylitic ash flow tuffs of latest Oligocene to early Miocene age (30 to 22 Ma) occur in the Fort Sage Mountains and in the Sierra Nevada but are not apparent in wells drilled in the Honey Lake basin. Though other interpretations can be made, the authors take this as evidence that the basin did not exist at that time. Volcanic rocks as old as 12 Ma do occur in the basin indicating initiation in mid-Miocene time probably as a grabenmore » due to block faulting. Syntectonic andesitic and basaltic volcanism occurred along faults bounding the Sierra Nevada block at 9 to 10 Ma. Lava issuing from these fractures flowed westward along Tertiary drainages indicating that the Sierran block had been uplifted and tilted westward. Andesites erupted during this time north and east of the basin are lithologically distinct from Sierran andesites. Strike-slip faulting began to dominate the tectonic setting of the region during late Pliocene and Quaternary time with the development of the Honey Lake Fault Zone. Holocene strike-slip displacement is indicated by offsets of the 12,000 year old Lake Lahontan shoreline and deposits containing a 7,000 year old ash.« less

An approach to hydrogeological modeling of a large system of groundwater-fed lakes and wetlands in the Nebraska Sand Hills, USA

NASA Astrophysics Data System (ADS)

Rossman, Nathan R.; Zlotnik, Vitaly A.; Rowe, Clinton M.

2018-05-01

The feasibility of a hydrogeological modeling approach to simulate several thousand shallow groundwater-fed lakes and wetlands without explicitly considering their connection with groundwater is investigated at the regional scale ( 40,000 km2) through an application in the semi-arid Nebraska Sand Hills (NSH), USA. Hydraulic heads are compared to local land-surface elevations from a digital elevation model (DEM) within a geographic information system to assess locations of lakes and wetlands. The water bodies are inferred where hydraulic heads exceed, or are above a certain depth below, the land surface. Numbers of lakes and/or wetlands are determined via image cluster analysis applied to the same 30-m grid as the DEM after interpolating both simulated and estimated heads. The regional water-table map was used for groundwater model calibration, considering MODIS-based net groundwater recharge data. Resulting values of simulated total baseflow to interior streams are within 1% of observed values. Locations, areas, and numbers of simulated lakes and wetlands are compared with Landsat 2005 survey data and with areas of lakes from a 1979-1980 Landsat survey and the National Hydrography Dataset. This simplified process-based modeling approach avoids the need for field-based morphology or water-budget data from individual lakes or wetlands, or determination of lake-groundwater exchanges, yet it reproduces observed lake-wetland characteristics at regional groundwater management scales. A better understanding of the NSH hydrogeology is attained, and the approach shows promise for use in simulations of groundwater-fed lake and wetland characteristics in other large groundwater systems.

Science to Sustain Terminal Lakes: The Walker River Basin Study

USGS Publications Warehouse

,

2005-01-01

Section 2507 of Public Law 107-171 (2002 Farm Bill) provided $200,000,000 to be used by the Secretary of the Interior, acting through the Commissioner of Reclamation, to provide water to at-risk natural desert terminal lakes. This bill was later amended under Public Law 108-7, Section 207 to include language 'Restoration of fish, wildlife, and associated habitats in watersheds of certain lakes'. The amendment specified that only Pyramid, Summit, and Walker Lakes in the State of Nevada were to be considered under Section 2507, Public Law 107-171.

Great Salt Lake and Bonneville Salt Flats, UT, USA

NASA Technical Reports Server (NTRS)

1992-01-01

This is a view of the Great Salt Lake and nearby Bonneville Salt Flats, UT, (41.0N, 112.5W). A railroad causeway divides the lake with a stark straight line changing the water level and chemistry of the lake as a result. Fresh water runoff enters from the south adding to the depth and reducing the salinity. The north half receives little frsh water and is more saline and shallow. The Bonnieville Salt Flats is the lakebed of a onetime larger lake.

Great Salt Lake and Bonneville Salt Flats, UT, USA

NASA Image and Video Library

1992-04-02

This is a view of the Great Salt Lake and nearby Bonneville Salt Flats, UT, (41.0N, 112.5W). A railroad causeway divides the lake with a stark straight line changing the water level and chemistry of the lake as a result. Fresh water runoff enters from the south adding to the depth and reducing the salinity. The north half receives little frsh water and is more saline and shallow. The Bonnieville Salt Flats is the lakebed of a onetime larger lake.

Audiomagnetotelluric Data and Preliminary Two-Dimensional Models from Spring, Dry Lake, and Delamar Valleys, Nevada

USGS Publications Warehouse

McPhee, Darcy K.; Chuchel, Bruce A.; Pellerin, Louise

2008-01-01

This report presents audiomagnetotelluric (AMT) data along fourteen profiles in Spring, Delamar, and Dry Lake Valleys, and the corresponding preliminary two-dimensional (2-D) inverse models. The AMT method is a valuable tool for estimating the electrical resistivity of the Earth over depth ranges from a few meters to less than one kilometer, and it is important for revealing subsurface structure and stratigraphy within the Basin and Range province of eastern Nevada, which can be used to define the geohydrologic framework of the region. We collected AMT data by using the Geometrics StrataGem EH4 system. Profiles were 0.7 - 3.2 km in length with station spacing of 50-400 m. Data were recorded in a coordinate system parallel to and perpendicular to the regional geologic-strike direction with Z positive down. We show AMT station locations, sounding curves of apparent resistivity, phase, and coherency, and 2-D models of subsurface resistivity along the profiles. The 2-D inverse models are computed from the transverse electric (TE), transverse magnetic (TM), and TE+TM mode data by using a conjugate gradient, finite-difference method. Preliminary interpretation of the 2-D models defines the structural framework of the basins and the resistivity contrasts between alluvial basin-fill, volcanic units, and carbonate basement rocks.

Response of Sierra Nevada vegetation and fire regimes to past climate changes

Treesearch

R. Scott Anderson

2004-01-01

The study of changing vegetation patterns within forested communities of the Sierra Nevada has had a long history, initiated by the great naturalist John Muir. More recently, paleoecologists, who study ecosystems of the past, have analyzed fossil plant remains recovered from lake and meadow sediments to understand the regional biogeography and disturbance history of...

Is there a pattern to oxbow lake geomorphic evolution?

NASA Astrophysics Data System (ADS)

Dieras, P.; Constantine, J. A.

2012-04-01

Oxbow lakes are located along the floodplain corridor and created after meander cutoff. They are of high ecological value as they provide relatively calm wetlands which are regularly supplied with nutrients during floods. The persistence of oxbow lakes has been observed to vary from decades to several hundreds of years but little is known about the controls on their longevity. This study aims to ascertain if there is a common pattern in the water decrease of oxbow lakes and to define the controls on the lakes' longevity. The longevity of 37 oxbow lakes from 7 rivers from different parts of the world has been studied. The Towy River (Wales), the Ain River (France) and the Sacramento River (CA, USA) are largely dominated by oxbow lakes created after chute cutoff which is the incision of a chute across the floodplain; whereas the Mississippi River (MS, USA), the Kansas River (KS, USA), the Red River (MN, USA) and the Otter Tail River (MN, USA) show a large number of neck cutoffs which occur when two meanders migrate into one another. The water surface area decrease has been measured for all the sites using aerial photographs. Results revealed that the longevity of oxbow lakes is significantly affected by the type of cutoff. The lakes formed by chute cutoff lose very rapidly most of the water surface area of the initial channel as it is reduce by >80% within the first 10 to 30 years following cutoff for most sites. The water surface area of chute cutoff shows a logarithmic decrease with a fast decrease rate following cutoff, followed by a much slower loss of water surface area. The change in water decrease rate appears to be related to the moment of obstruction of the former channel entrance by sediment aggradation. In contrast, lakes formed by neck cutoff persist for much longer in the landscape and lose 40 to 60% within the first decades but then they maintain this water surface area for longer than a century. The cutoff process is therefore the main control on the

SHRIMP-RG U-Pb isotopic systematics of zircon from the Angel Lake orthogneiss, East Humboldt Range, Nevada: is this really Archean crust? REPLY

USGS Publications Warehouse

Premo, Wayne R.

2010-01-01

The comments from McGrew and Snoke are well received and their concerns for the interpretations in our paper (Premo et al., 2008), which questions the original contention that the Angel Lake orthogneiss is an Archean rock, are many and varied—all of which we will attempt to address. As they point out, this issue is an important one as this particular crustal exposure may delimit the southwestern extent of the Archean Wyoming province (Foster et al., 2006; Mueller and Frost, 2006), which has implications for the true crustal evolution of this region of the Great Basin and perhaps more importantly its relationship (if any) to the location of the world-class gold deposits of north-central Nevada (e.g., Howard, 2003).

A 400-year phytolith-based reconstruction of wild rice (Zizania palustris) abundance from Mud Lake core sediments, Fond du Lac Band of Lake Superior Chippewa Reservation, Minnesota, USA.

NASA Astrophysics Data System (ADS)

Munoz, R.; Caylor, E.; Yost, C. L.; Drake, C.; Ladwig, J. L.; Myrbo, A.; Howes, T.

2014-12-01

Wild rice (Zizania palustris L.) is an aquatic grass with spiritual and subsistence significance to Native people of the Great Lakes region of North America. Mud Lake (Mashkiigwaagamaag), located on the Fond du Lac Band of Lake Superior Chippewa Reservation in Carlton County, Minnesota, USA, once supported an extensive population of wild rice (manoomin). However, early 20th century attempts to ditch and drain surrounding wetlands for landuse intensification severely altered the natural hydrological system that supports wild rice. Fond du Lac Resource Management (FDLRM) technicians are currently working to increase the wild rice population in Mud Lake. As part of these efforts, this phytolith study was undertaken to better understand how wild rice abundance has fluctuated over the past 400 years, with particular emphasis on the 19th and 20th centuries. Phytoliths are microscopic opal silica plant remains that are incorporated into soils and lake sediments after the plant-parts that contain them decay. Wild rice produces phytolith morphotypes that are unequivocally diagnostic. Mud Lake core MNMN-MUD11-1C-1P-1 (46°43'38.39"N, 92°42'2.45"W) was piston cored by LacCore (National Lacustrine Core Facility) and FDLRM technicians on 24 May 2011. Initial core descriptions, multi-sensor core logging, phytolith sampling and phytolith extractions were completed during the summer of 2014 at LacCore. Wild rice phytolith identification and quantification was conducted on twelve samples using brightfield microscopy at 400x magnification. Wild rice phytolith concentration values ranged from 68 to 2,300 phytoliths/cm3. Wild rice accumulation rates ranged from 9 to 383 phytoliths/ cm2/yr, peaking in 1952 AD. Wild rice abundance in Mud Lake appears to be influenced by a complex set of variables that include anthropogenic disturbance, climatic events and aquatic plant community succession.

Sierra Nevada Rock Glaciers: Biodiversity Refugia in a Warming World?

NASA Astrophysics Data System (ADS)

Millar, C. I.; Westfall, R. D.

2007-12-01

Rock glaciers and related periglacial rock-ice features (RIFs) are common landforms in high, dry mountain ranges, and widely distributed throughout canyons of the Sierra Nevada, California, USA (Millar & Westfall, in press). Due to insulating rock carapaces, active rock glaciers (ice-cored) have been documented to maintain ice longer, and thus contribute to more enduring hydrologic output, under past warming climates than typical ice glaciers. This function has been suggested for the coming century. We propose a broader hydrologic and ecologic role for RIFs as temperatures rise in the future. For the Sierra Nevada, we suggest that canyons with either active or relict RIFs (Holocene and Pleistocene) maintain water longer and distribute water more broadly than canyons that were scoured by ice glaciers and are defined by primary river and lake systems. RIFs provide persistent, distributed water for extensive wetland habitat, rare in these otherwise barren, high, and dry locations. We mapped and assessed the area of wetlands surrounding active and relict RIFs from the central eastern Sierra Nevada; from these we delineated wetland vegetation community types and recorded plant species found in RIF-supported wetlands. Mid-elevation RIFs, likely inactive or with transient ice, develop soil patches on their rock matrix. At the Barney Rock Glacier (Duck Pass, Mammoth Crest), we inventoried plant species on all soil patches, and measured cover for each species per patch and total plant cover for the rock glacier. RIF landforms also appear to support high-elevation mammals. We show that American beaver (Castor canadensis) is associated with canyons dominated by active or relict RIFs and propose that the articulating, persistent, and distributed nature of streams makes dam-building easier than other canyons. Beavers further contribute to maintaining water and creating wetland habitat in upper watersheds by engineering ponds and marshes, and contributing to riparian extent. We

Response of aquatic macrophytes to human land use perturbations in the watersheds of Wisconsin lakes, U.S.A.

USGS Publications Warehouse

Sass, Laura L.; Bozek, Michael A.; Hauxwell, Jennifer A.; Wagner, Kelly; Knight, Susan

2010-01-01

Aquatic macrophyte communities were assessed in 53 lakes in Wisconsin, U.S.A. along environmental and land use development gradients to determine effects human land use perturbations have on aquatic macrophytes at the watershed and riparian development scales. Species richness and relative frequency were surveyed in lakes from two ecoregions: the Northern Lakes and Forests Ecoregion and the Southeastern Wisconsin Till Plain Ecoregion. Lakes were selected along a gradient of watershed development ranging from undeveloped (i.e., forested), to agricultural to urban development. Land uses occurring in the watershed and in perimeters of different width (0–100, 0–200, 0–500, and 0–1000 m from shore, in the watershed) were used to assess effects on macrophyte communities. Snorkel and SCUBA were used to survey aquatic macrophyte species in 18 quadrats of 0.25 m2 along 14 transects placed perpendicular to shore in each lake. Effects of watershed development (e.g., agriculture and/or urban) were tested at whole-lake (entire littoral zone) and near-shore (within 7 m of shore) scales using canonical correspondence analysis (CCA) and linear regression. Overall, species richness was negatively related to watershed development, while frequencies of individual species and groups differed in level of response to different land use perturbations. Effects of land use in the perimeters on macrophytes, with a few exceptions, did not provide higher correlations compared to land use at the watershed scale. In lakes with higher total watershed development levels, introduced species, particularly Myriophyllumspicatum, increased in abundance and native species, especially potamids, isoetids, and floating-leaved plants, declined in abundance. Correlations within the northern and southeastern ecoregions separately were not significant. Multivariate analyses suggested species composition is driven by environmental responses as well as human development pressures. Both water

A Holocene Sediment Record of Phosphorus Accumulation in Shallow Lake Harris, Florida (USA) Offers New Perspectives on Recent Cultural Eutrophication

PubMed Central

Kenney, William F.; Brenner, Mark; Curtis, Jason H.; Arnold, T. Elliott; Schelske, Claire L.

2016-01-01

We studied a complete Holocene sediment record from shallow (zmax = 9.7 m) Lake Harris, Florida (USA) to infer the historical development of the lake and its current eutrophic status. We used 210Pb and 14C to date the 5.9-m sediment sequence (core LH-6-13) and determined accumulation rates for bulk sediment, organic matter, calcium carbonate, phosphorus fractions and biogenic silica fractions. The chronology of changes in sediment characteristics for LH-6-13 is consistent with the general paleoenvironmental framework established by core studies from other Florida lakes. Lake Harris began to fill with water in the early Holocene, ca. 10,680 cal a BP. A shift from carbonate-dominated to organic-rich sediments ca. 5,540 cal a BP corresponds to a transition to wetter climate in the middle Holocene. A rapid increase in diatom biogenic silica concentrations and accumulation rates ca. 2,600 cal a BP signals that the lake had deepened to its modern limnetic state. In LH-6-13, an up-core decrease in rates of accumulation for several sediment variables indicates time-course oligotrophication of the lake through the Holocene. In near-surface sediments, abrupt increases in the accumulation rates of these same variables indicate progressive cultural eutrophication after ca. AD 1900. Comparison of the modern state of Lake Harris to its condition 50–100 years ago provides a measure of the impact of recent cultural eutrophication. Because the pre-disturbance trajectory of this lake was one of oligotrophication, the true impact of cultural eutrophication is even greater than what is inferred from the changes over the past century. PMID:26789518

Groundwater exchanges near a channelized versus unmodified stream mouth discharging to a subalpine lake

USGS Publications Warehouse

Constantz, James; Naranjo, Ramon C.; Niswonger, Richard G.; Allander, Kip K.; Neilson, B.; Rosenberry, Donald O.; Smith, David W.; Rosecrans, C.; Stonestrom, David A.

2016-01-01

The terminus of a stream flowing into a larger river, pond, lake, or reservoir is referred to as the stream-mouth reach or simply the stream mouth. The terminus is often characterized by rapidly changing thermal and hydraulic conditions that result in abrupt shifts in surface water/groundwater (sw/gw) exchange patterns, creating the potential for unique biogeochemical processes and ecosystems. Worldwide shoreline development is changing stream-lake interfaces through channelization of stream mouths, i.e., channel straightening and bank stabilization to prevent natural meandering at the shoreline. In the central Sierra Nevada (USA), Lake Tahoe's shoreline has an abundance of both “unmodified” (i.e., not engineered though potentially impacted by broader watershed engineering) and channelized stream mouths. Two representative stream mouths along the lake's north shore, one channelized and one unmodified, were selected to compare and contrast water and heat exchanges. Hydraulic and thermal properties were monitored during separate campaigns in September 2012 and 2013 and sw/gw exchanges were estimated within the stream mouth-shoreline continuum. Heat-flow and water-flow patterns indicated clear differences in the channelized versus the unmodified stream mouth. For the channelized stream mouth, relatively modulated, cool-temperature, low-velocity longitudinal streambed flows discharged offshore beneath warmer buoyant lakeshore water. In contrast, a seasonal barrier bar formed across the unmodified stream mouth, creating higher-velocity subsurface flow paths and higher diurnal temperature variations relative to shoreline water. As a consequence, channelization altered sw/gw exchanges potentially altering biogeochemical processing and ecological systems in and near the stream mouth.

Interaction of an Introduced Predator with Future Effects of Climate Change in the Recruitment Dynamics of the Imperiled Sierra Nevada Yellow-legged Frog (Rana sierrae)

Treesearch

I Lacan; Kathleen R. Matthews; K.V. Feldman

2008-01-01

Between-year variation in snowpack (from 20 to 200% of average) and summer rainfall cause large fluctuations in volume of small lakes in the higher elevation (> 3000 m) Sierra Nevada, which are important habitat for the imperiled Sierra Nevada Yellow-legged Frog, Rana sierrae. Climate change (global warming) is predicted to increase these...

Climate variability during the deglaciation and Holocene in a high-altitude alpine lake deduced from the sedimentary record from Laguna Seca, Sierra Nevada, southern Iberian Peninsula

NASA Astrophysics Data System (ADS)

Camuera, Jon; Jiménez-Moreno, Gonzalo; José Ramos-Román, María; García-Alix, Antonio; Jiménez-Espejo, Francisco; Anderson, R. Scott

2017-04-01

High-resolution X-ray fluorescence (XRF), magnetic susceptibility (MS), color and lithological analyses have been carried out on a 3.6 m-long sediment core from Laguna Seca, a high-elevation dry lake from Sierra Nevada mountain range, southern Spain. This is the longest sedimentary record retrieved from an alpine lake in southern Iberian Peninsula. Besides, alpine lakes are very sensitive environments to climate changes and previous studies showed that Laguna Seca could provide an excellent record to identify millennial-scale climate variations during deglaciation and the whole Holocene. XRF analyses, in particular high calcium and low K/Ca ratios, show aridity phases, very well represented during Last Glacial Maximum (LGM) and the Younger Dryas (YD). Arid events are also shown at ca. 8.1 ka BP, ca. 4.4 ka BP and the latest Holocene. On the other hand, negative values in calcium and positive values in K/Ca appear in the Bølling-Allerød (BA) and during the early Holocene until ca. 6 ka BP, indicating more humidity and higher run-off. A progressive aridification trend is also observed in the Holocene, changing from more humid conditions during the early Holocene to more aridity during the late Holocene.

Geometry and kinematics of the eastern Lake Mead fault system in the Virgin Mountains, Nevada and Arizona

USGS Publications Warehouse

Beard, Sue; Campagna, David J.; Anderson, R. Ernest

2010-01-01

The Lake Mead fault system is a northeast-striking, 130-km-long zone of left-slip in the southeast Great Basin, active from before 16 Ma to Quaternary time. The northeast end of the Lake Mead fault system in the Virgin Mountains of southeast Nevada and northwest Arizona forms a partitioned strain field comprising kinematically linked northeast-striking left-lateral faults, north-striking normal faults, and northwest-striking right-lateral faults. Major faults bound large structural blocks whose internal strain reflects their position within a left step-over of the left-lateral faults. Two north-striking large-displacement normal faults, the Lakeside Mine segment of the South Virgin–White Hills detachment fault and the Piedmont fault, intersect the left step-over from the southwest and northeast, respectively. The left step-over in the Lake Mead fault system therefore corresponds to a right-step in the regional normal fault system.Within the left step-over, displacement transfer between the left-lateral faults and linked normal faults occurs near their junctions, where the left-lateral faults become oblique and normal fault displacement decreases away from the junction. Southward from the center of the step-over in the Virgin Mountains, down-to-the-west normal faults splay northward from left-lateral faults, whereas north and east of the center, down-to-the-east normal faults splay southward from left-lateral faults. Minimum slip is thus in the central part of the left step-over, between east-directed slip to the north and west-directed slip to the south. Attenuation faults parallel or subparallel to bedding cut Lower Paleozoic rocks and are inferred to be early structures that accommodated footwall uplift during the initial stages of extension.Fault-slip data indicate oblique extensional strain within the left step-over in the South Virgin Mountains, manifested as east-west extension; shortening is partitioned between vertical for extension-dominated structural

Environmental Assessment for Travis AFB C-17 Use of Instrument Routes 264, 275, 280, 281 , and 282 in Central Nevada

DTIC Science & Technology

2013-09-01

alteration of surface water flows that would change existing downstream flows . Although wetlands occur within central Nevada, none of the activities...Range Ecoregion is internally drained by rivers flowing off the east slopes of the Sierra Nevada and by the Humboldt River, one of the longest...Valley and near Humboldt Lake are at the terminus of rivers; they receive return flow from flood-irrigated fields which, in turn, degrades water

Phytoplankton dynamics in three Rocky Mountain lakes, Colorado, USA

USGS Publications Warehouse

McKnight, Diane M.; Smith, R.L.; Bradbury, J.P.; Baron, Jill S.; Spaulding, S.

1990-01-01

In 1984 and 1985 seasonal changes in phytoplankton were studied in a system of three lakes in Loch Vale, Rocky Mountain National Park, Colorado. Three periods were evident: (1) A spring bloom, during snowmelt, of the planktonic diatom Asterionella formosa, (2) a mid-summer period of minimal algal abundance, and (3) a fall bloom of the blue-green alga Oscillatoria limnetica. Seasonal phytoplankton dynamics in these lakes are controlled partially by the rapid flushing rate during snowmelt and the transport of phytoplankton from the highest lake to the lower lakes by the stream, Icy Brook. During snowmelt, the A. formosa population in the most downstream lake has a net rate of increase of 0.34 d-1, which is calculated from the flushing rate and from the A. formosa abundance in the inflow from the upstream lake and in the downstream lake. Measurement of photosynthetic rates at different depths during the three periods confirmed the rapid growth of A. formosa during the spring. The decline in A. formosa after snowmelt may be related to grazing by developing zooplankton populations. The possible importance of the seasonal variations in nitrate concentrations were evaluated in situ enrichment experiments. For A. formosa and O. limnetica populations, growth stimulation resulted from 8- or 16-micromolar amendments of calcium nitrate and sulfuric acid, but the reason for this stimulation could not be determined from these experiments.

Spatial Patterns of Atmospherically Deposited Organic Contaminants at High-Elevation in the Southern Sierra Nevada Mountains, California, USA

PubMed Central

Bradford, David F.; Stanley, Kerri; McConnell, Laura L.; Tallent-Halsell, Nita G.; Nash, Maliha S.; Simonich, Staci M.

2011-01-01

Atmospherically deposited contaminants in the Sierra Nevada mountains of California, USA have been implicated as adversely affecting amphibians and fish, yet little is known about the distributions of contaminants within the mountains, particularly at high elevation. We tested the hypothesis that contaminant concentrations in a high-elevation portion of the Sierra Nevada decrease with distance from the adjacent San Joaquin Valley. We sampled air, sediment, and tadpoles twice at 28 water bodies in 14 dispersed areas in Sequoia and Kings Canyon National Parks (2785 – 3375 m elevation; 43 – 82 km from Valley edge). We detected up to 15 chemicals frequently in sediment and tadpoles, including current- and historic-use pesticides, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons. Only β-endosulfan was found frequently in air. Concentrations of all chemicals detected were very low, averaging in the parts-per-billion range or less in sediment and tadpoles, and on the order of 10 pg/m3 for β-endosulfan in air. Principal components analysis indicated that chemical compositions were generally similar among sites, suggesting that chemical transport patterns were likewise similar among sites. In contrast, transport processes did not appear to strongly influence concentration differences among sites because variation in concentrations among nearby sites was high relative to sites far from each other. Moreover, a general relationship for concentrations as a function of distance from the valley was not evident across chemical, medium, and time. Nevertheless, concentrations for some chemical/medium/time combinations showed significant negative relationships with metrics for distance from the Valley. However, the magnitude of these distance effects among high-elevation sites was small relative to differences found in other studies between the valley edge and the nearest high-elevation sites. PMID:20821540

Shorthair meadows in the high Sierra Nevada...an hypothesis of their development

Treesearch

Raymond D. Ratliff

1973-01-01

Bands of shorthair meadow are found around lakes in the high Sierra Nevada of California. A hypothesis, based on observations in the Kings Canyon National Park, to explain the development of these meadows is offered: Boulders form the foundation upon which American-laurel, Sierra bilberry, and moss combine to produce thick mats. The lower layers of the mats are...

Multiple component end-member mixing model of dilution: hydrochemical effects of construction water at Yucca Mountain, Nevada, USA

NASA Astrophysics Data System (ADS)

Lu, Guoping; Sonnenthal, Eric L.; Bodvarsson, Gudmundur S.

2008-12-01

The standard dual-component and two-member linear mixing model is often used to quantify water mixing of different sources. However, it is no longer applicable whenever actual mixture concentrations are not exactly known because of dilution. For example, low-water-content (low-porosity) rock samples are leached for pore-water chemical compositions, which therefore are diluted in the leachates. A multicomponent, two-member mixing model of dilution has been developed to quantify mixing of water sources and multiple chemical components experiencing dilution in leaching. This extended mixing model was used to quantify fracture-matrix interaction in construction-water migration tests along the Exploratory Studies Facility (ESF) tunnel at Yucca Mountain, Nevada, USA. The model effectively recovers the spatial distribution of water and chemical compositions released from the construction water, and provides invaluable data on the matrix fracture interaction. The methodology and formulations described here are applicable to many sorts of mixing-dilution problems, including dilution in petroleum reservoirs, hydrospheres, chemical constituents in rocks and minerals, monitoring of drilling fluids, and leaching, as well as to environmental science studies.

Directly dated MIS 3 lake-level record from Lake Manix, Mojave Desert, California, USA

USGS Publications Warehouse

Reheis, Marith; Miller, David M.; McGeehin, John P.; Redwine, Joanna R.; Oviatt, Charles G.; Bright, Jordon E.

2015-01-01

An outcrop-based lake-level curve, constrained by ~ 70 calibrated 14C ages on Anodonta shells, indicates at least 8 highstands between 45 and 25 cal ka BP within 10 m of the 543-m upper threshold of Lake Manix in the Mojave Desert of southern California. Correlations of Manix highstands with ice, marine, and speleothem records suggest that at least the youngest three highstands coincide with Dansgaard–Oeschger (D–O) stadials and Heinrich events 3 and 4. The lake-level record is consistent with results from speleothem studies in the Southwest that indicate cool wet conditions during D–O stadials. Notably, highstands between 43 and 25 ka apparently occurred at times of generally low levels of pluvial lakes farther north as interpreted from core-based proxies. Mojave lakes may have been supported by tropical moisture sources during oxygen-isotope stage 3, perhaps controlled by southerly deflection of Pacific storm tracks due to weakening of the sea-surface temperature gradient in response to North Atlantic climate perturbations.

Geology and mineral deposits of Churchill County, Nevada

USGS Publications Warehouse

Willden, Ronald; Speed, Robert C.

1974-01-01

Churchill County, in west-central Nevada, is an area of varied topography and geology that has had a rather small total mineral production. The western part of the county is dominated by the broad low valley of the Carson Sink, which is underlain by deposits of Lake Lahontan. The bordering mountain ranges to the west and south are of low relief and underlain largely by Tertiary volcanic and sedimentary units. Pre-Tertiary rocks are extensively exposed east of the Carson Sink in the Stillwater Range, Clan Alpine Mountains, Augusta Mountains, and New Pass Mountains. The eastern valleys are underlain by Quaternary alluvial and lacustrine deposits contemporaneous with the western deposits of Lake Lahontan. The eastern mountain ranges are more rugged than the western ranges and have higher relief; the eastern valleys are generally narrower.

Gasoline-Related Compounds in Lakes Mead and Mohave, Nevada, 2004-06

USGS Publications Warehouse

Lico, Michael S.; Johnson, B. Thomas

2007-01-01

The distribution of man-made organic compounds, specifically gasoline-derived compounds, was investigated from 2004 to 2006 in Lakes Mead and Mohave and one of its tributary streams, Las Vegas Wash. Compounds contained in raw gasoline (benzene, toluene, ethylbenzene, xylenes; also known as BTEX compounds) and those produced during combustion of gasoline (polycyclic aromatic hydrocarbon compounds; also known as PAH compounds) were detected at every site sampled in Lakes Mead and Mohave. Water-quality analyses of samples collected during 2004-06 indicate that motorized watercraft are the major source of these organic compounds to the lakes. Concentrations of BTEX increase as the boating season progresses and decrease to less than detectable levels during the winter when few boats are on the water. Volatilization and microbial degradation most likely are the primary removal mechanisms for BTEX compounds in the lakes. Concentrations of BTEX compounds were highest at sampling points near marinas or popular launching areas. Methyl tert-butyl ether (MTBE) was detected during 2004 but concentrations decreased to less than the detection level during the latter part of the study; most likely due to the removal of MTBE from gasoline purchased in California. Distribution of PAH compounds was similar to that of BTEX compounds, in that, concentrations were highest at popular boating areas and lowest in areas where fewer boats traveled. PAH concentrations were highest at Katherine Landing and North Telephone Cove in Lake Mohave where many personal watercraft with carbureted two-stroke engines ply the waters. Lake-bottom sediment is not a sink for PAH as indicated by the low concentrations detected in sediment samples from both lakes. PAH compounds most likely are removed from the lakes by photochemical degradation. PAH compounds in Las Vegas Wash, which drains the greater Las Vegas metropolitan area, were present in relatively high concentrations in sediment from the upstream

Holocene multidecadal and multicentennial droughts affecting Northern California and Nevada

USGS Publications Warehouse

Benson, L.; Kashgarian, Michaele; Rye, R.; Lund, S.; Paillet, F.; Smoot, J.; Kester, C.; Mensing, S.; Meko, D.; Lindstrom, S.

2002-01-01

Continuous, high-resolution ??18O records from cored sediments of Pyramid Lake, Nevada, indicate that oscillations in the hydrologic balance occurred, on average, about every 150 years (yr) during the past 7630 calendar years (cal yr). The records are not stationary; during the past 2740 yr, drought durations ranged from 20 to 100 yr and intervals between droughts ranged from 80 to 230 yr. Comparison of tree-ring-based reconstructions of climate change for the past 1200 yr from the Sierra Nevada and the El alpais region of northwest New Mexico indicates that severe droughts associated with Anasazi withdrawal from Chaco Canyon at 820 cal yr BP (calendar years before present) and final abandonment of Chaco Canyon, Mesa Verde, and the Kayenta area at 650 cal yr BP may have impacted much of the western United States.During the middle Holocene (informally defined in this paper as extending from 8000 to 3000 cal yr BP), magnetic susceptibility values of sediments deposited in Pyramid Lake's deep basin were much larger than late-Holocene (3000-0 cal yr BP) values, indicating the presence of a shallow lake. In addition, the mean ?? 18O value of CaCO3 precipitated between 6500 and 3430 cal yr BP was 1.6??? less than the mean value of CaCO3 precipitated after 2740 cal yr BP. Numerical calculations indicate that the shift in the ??18O baseline probably resulted from a transition to a wetter (> 30%) and cooler (3-5??C) climate. The existence of a relatively dry and warm middle-Holocene climate in the Truckee River - Pyramid Lake system is generally consistent with archeological, sedimentological, chemical, physical, and biological records from various sites within the Great Basin of the western United States. Two high-resolution Holocene-climate records are now available from the Pyramid and Owens lake basins which suggest that the Holocene was characterized by five climatic intervals. TIC and ??18O records from Owens Lake indicate that the first interval in the early Holocene

Holocene multidecadal and multicentennial droughts affecting Northern California and Nevada

NASA Astrophysics Data System (ADS)

Benson, Larry; Kashgarian, Michaele; Rye, Robert; Lund, Steve; Paillet, Fred; Smoot, Joseph; Kester, Cynthia; Mensing, Scott; Meko, Dave; Lindström, Susan

2002-02-01

Continuous, high-resolution δ18O records from cored sediments of Pyramid Lake, Nevada, indicate that oscillations in the hydrologic balance occurred, on average, about every 150 years (yr) during the past 7630 calendar years (cal yr). The records are not stationary; during the past 2740 yr, drought durations ranged from 20 to 100 yr and intervals between droughts ranged from 80 to 230 yr. Comparison of tree-ring-based reconstructions of climate change for the past 1200 yr from the Sierra Nevada and the El Malpais region of northwest New Mexico indicates that severe droughts associated with Anasazi withdrawal from Chaco Canyon at 820 cal yr BP (calendar years before present) and final abandonment of Chaco Canyon, Mesa Verde, and the Kayenta area at 650 cal yr BP may have impacted much of the western United States.During the middle Holocene (informally defined in this paper as extending from 8000 to 3000 cal yr BP), magnetic susceptibility values of sediments deposited in Pyramid Lake's deep basin were much larger than late-Holocene (3000-0 cal yr BP) values, indicating the presence of a shallow lake. In addition, the mean δ18O value of CaCO 3 precipitated between 6500 and 3430 cal yr BP was 1.6‰ less than the mean value of CaCO 3 precipitated after 2740 cal yr BP. Numerical calculations indicate that the shift in the δ18O baseline probably resulted from a transition to a wetter (>30%) and cooler (3-5°C) climate. The existence of a relatively dry and warm middle-Holocene climate in the Truckee River-Pyramid Lake system is generally consistent with archeological, sedimentological, chemical, physical, and biological records from various sites within the Great Basin of the western United States. Two high-resolution Holocene-climate records are now available from the Pyramid and Owens lake basins which suggest that the Holocene was characterized by five climatic intervals. TIC and δ18O records from Owens Lake indicate that the first interval in the early Holocene

Vertebrate paleontology, stratigraphy, and paleohydrology of Tule Springs Fossil Beds National Monument, Nevada (USA)

USGS Publications Warehouse

Springer, Kathleen; Pigati, Jeffery S.; Scott, Eric

2017-01-01

Tule Springs Fossil Beds National Monument (TUSK) preserves 22,650 acres of the upper Las Vegas Wash in the northern Las Vegas Valley (Nevada, USA). TUSK is home to extensive and stratigraphically complex groundwater discharge (GWD) deposits, called the Las Vegas Formation, which represent springs and desert wetlands that covered much of the valley during the late Quaternary. The GWD deposits record hydrologic changes that occurred here in a dynamic and temporally congruent response to abrupt climatic oscillations over the last ~300 ka (thousands of years). The deposits also entomb the Tule Springs Local Fauna (TSLF), one of the most significant late Pleistocene (Rancholabrean) vertebrate assemblages in the American Southwest. The TSLF is both prolific and diverse, and includes a large mammal assemblage dominated by Mammuthus columbi and Camelops hesternus. Two (and possibly three) distinct species of Equus, two species of Bison, Panthera atrox, Smilodon fatalis, Canis dirus, Megalonyx jeffersonii, and Nothrotheriops shastensis are also present, and newly recognized faunal components include micromammals, amphibians, snakes, and birds. Invertebrates, plant macrofossils, and pollen also occur in the deposits and provide important and complementary paleoenvironmental information. This field compendium highlights the faunal assemblage in the classic stratigraphic sequences of the Las Vegas Formation within TUSK, emphasizes the significant hydrologic changes that occurred in the area during the recent geologic past, and examines the subsequent and repeated effect of rapid climate change on the local desert wetland ecosystem.

Recent crustal movements in the Sierra Nevada-Walker lane region of California-Nevada: Part i, rate and style of deformation

USGS Publications Warehouse

Slemmons, D.B.; Wormer, D.V.; Bell, E.J.; Silberman, M.L.

1979-01-01

This review of geological, seismological, geochronological and paleobotanical data is made to compare historic and geologic rates and styles of deformation of the Sierra Nevada and western Basin and Range Provinces. The main uplift of this region began about 17 m.y. ago, with slow uplift of the central Sierra Nevada summit region at rates estimated at about 0.012 mm/yr and of western Basin and Range Province at about 0.01 mm/yr. Many Mesozoic faults of the Foothills fault system were reactivated with normal slip in mid-Tertiary time and have continued to be active with slow slip rates. Sparse data indicate acceleration of rates of uplift and faulting during the Late Cenozoic. The Basin and Range faulting appears to have extended westward during this period with a reduction in width of the Sierra Nevada. The eastern boundary zone of the Sierra Nevada has an irregular en-echelon pattern of normal and right-oblique faults. The area between the Sierra Nevada and the Walker Lane is a complex zone of irregular patterns of ho??rst and graben blocks and conjugate normal-to right- and left-slip faults of NW and NE trend, respectively. The Walker Lane has at least five main strands near Walker Lake, with total right-slip separation estimated at 48 km. The NE-trending left-slip faults are much shorter than the Walker Lane fault zone and have maximum separations of no more than a few kilometers. Examples include the 1948 and 1966 fault zone northeast of Truckee, California, the Olinghouse fault (Part III) and possibly the almost 200-km-long Carson Lineament. Historic geologic evidence of faulting, seismologic evidence for focal mechanisms, geodetic measurements and strain measurements confirm continued regional uplift and tilting of the Sierra Nevada, with minor internal local faulting and deformation, smaller uplift of the western Basin and Range Province, conjugate focal mechanisms for faults of diverse orientations and types, and a NS to NE-SW compression axis (??1) and an

Geohydrology and evapotranspiration at Franklin Lake playa, Inyo County, California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Czarnecki, J.B.

1997-12-31

Franklin Lake playa is one of the principal discharge areas of the Furnace Creek Ranch-Alkali Flat ground-water-flow system in southern Nevada and adjacent California. Yucca Mountain, Nevada, located within this flow system, is being evaluated by the US Department of Energy to determine its suitability as a potential site for a high-level nuclear-waste repository. To assist the U.S. Department of Energy with its evaluation of the Yucca Mountain site, the US Geological Survey developed a parameter-estimation model of the Furnace Creek Ranch-Alkali Flat ground-water-flow system. Results from sensitivity analyses made using the parameter-estimation model indicated that simulated rates of evapotranspirationmore » at Franklin Lake playa had the largest effect on the calculation of transmissivity values at Yucca Mountain of all the model-boundary conditions and, therefore, that evapotranspiration required careful definition.« less

Petrology and Geochemistry of an Upper Crustal Mafic Complex- Hidden Lakes, Sierra Nevada Batholith, California

NASA Astrophysics Data System (ADS)

Lewis, M.; Bucholz, C. E.; Jagoutz, O. E.; Eddy, M. P.

2017-12-01

Magmatic differentiation in arc settings is likely a polybaric process, with crystallization of primitive basalts occurring primarily in the lower crust and more evolved melts in the upper crust. The general lack of mafic-ultramafic cumulates in the silicic paleo-arc upper crust supports this model. However, the Sierra Nevada Batholith preserves numerous mafic intrusions up to 25 km2, suggesting that significant volumes of mafic magma may differentiate at shallow crustal levels. Previous studies on several such intrusions report ages contemporaneous with Cretaceous batholith emplacement (Coleman et al., 1995), but only a few have investigated their chemistry and relationship to arc magmatism (Frost, 1987; Frost & Mahood, 1987; Sisson et al., 1996). We present field observations, petrography, mineral chemistry, and bulk rock compositional data for the Hidden Lakes Mafic Complex (HLMC), located in the Central Sierra Nevada Batholith. Preliminary CA-ID-TIMS U-Pb zircon ages constrain crystallization between 90 and 95 Ma, slightly older than the surrounding Cretaceous felsic plutons (89-90 Ma) and younger than adjacent Jurassic granodiorites (172 Ma). This 2.2 km2 complex consists of biotite+amphibole gabbros through qtz-monzonites, in gradational contact, and contains local pods of biotite- and amphibole-bearing olivine-orthopyroxenites and gabbronorites. Mineral compositions and field relations suggest that these lithologies were derived from a common crystallization sequence. The most primitive olivine-pyroxenite contains olivine and orthopyroxene in equilibrium with a melt with Mg# 54. Subsequent crystallization over a temperature range of 1025 to 700°C produced more evolved lithologies up to qtz-monzonites. Al-in-hornblende calculations for HLMC qtz-monzonites indicate a crystallization depth of 9-10 km, well into the upper crust. The early crystallization of amphibole requires a parental basalt with >6 wt% H2O, which may have enabled it to ascend into the upper

Where is iron in erionite? A multidisciplinary study on fibrous erionite-Na from Jersey (Nevada, USA)

PubMed Central

Gualtieri, Alessandro F.; Gandolfi, Nicola Bursi; Pollastri, Simone; Pollok, Kilian; Langenhorst, Falko

2016-01-01

Fibrous erionite is a mineral fibre of great concern but to date mechanisms by which it induces cyto- and geno-toxic damage, and especially the role of iron associated to this zeolite species, remain poorly understood. One of the reasons is that we still don’t know exactly where iron is in natural erionite. This work is focused on fibrous erionite-Na from Jersey (Nevada, USA) and attempts to draw a general model of occurrence of iron in erionite and relationship with toxicity mechanisms. It was found that iron is present as 6-fold coordinated Fe3+ not part of the zeolite structure. The heterogeneous nature of the sample was revealed as receptacle of different iron-bearing impurities (amorphous iron-rich nanoparticles, micro-particles of iron oxides/hydroxides, and flakes of nontronite). If iron is not part of the structure, its role should be considered irrelevant for erionite toxicity, and other factors like biopersistence should be invoked. An alternative perspective to the proposed model is that iron rich nano-particles and nontronite dissolve in the intracellular acidic environment, leaving a residue of iron atoms at specific surface sites anchored to the windows of the zeolite channels. These sites may be active later as low nuclearity groups. PMID:27892512

Spatiotemporal drivers of dissolved organic matter in high alpine lakes: Role of Saharan dust inputs and bacterial activity.

PubMed

Mladenov, Natalie; Pulido-Villena, Elvira; Morales-Baquero, Rafael; Ortega-Retuerta, Eva; Sommaruga, Ruben; Reche, Isabel

2008-01-01

The effects of many environmental stressors such as UV radiation are mediated by dissolved organic matter (DOM) properties. Therefore, determining the factors shaping spatial and temporal patterns is particularly essential in the most susceptible, low dissolved organic carbon (DOC) lakes. We analyzed spatiotemporal variations in dissolved organic carbon concentration and dissolved organic matter optical properties (absorption and fluorescence) in 11 transparent lakes located above tree line in the Sierra Nevada Mountains (Spain), and we assessed potential external (evaporation and atmospheric deposition) and internal (bacterial abundance, bacterial production, chlorophyll a, and catchment vegetation) drivers of DOM patterns. At spatial and temporal scales, bacteria were related to chromophoric DOM (CDOM). At the temporal scale, water soluble organic carbon (WSOC) in dust deposition and evaporation were found to have a significant influence on DOC and CDOM in two Sierra Nevada lakes studied during the ice-free periods of 2000-2002. DOC concentrations and absorption coefficients at 320 nm were strongly correlated over the spatial scale (n = 11, R(2) = 0.86; p < 0.01), but inconsistently correlated over time, indicating seasonal and interannual variability in external factors and a differential response of DOC concentration and CDOM to these factors. At the continental scale, higher mean DOC concentrations and more CDOM in lakes of the Sierra Nevada than in lakes of the Pyrenees and Alps may be due to a combination of more extreme evaporation, and greater atmospheric dust deposition.

Spatiotemporal drivers of dissolved organic matter in high alpine lakes: Role of Saharan dust inputs and bacterial activity

PubMed Central

Mladenov, Natalie; Pulido-Villena, Elvira; Morales-Baquero, Rafael; Ortega-Retuerta, Eva; Sommaruga, Ruben; Reche, Isabel

2010-01-01

The effects of many environmental stressors such as UV radiation are mediated by dissolved organic matter (DOM) properties. Therefore, determining the factors shaping spatial and temporal patterns is particularly essential in the most susceptible, low dissolved organic carbon (DOC) lakes. We analyzed spatiotemporal variations in dissolved organic carbon concentration and dissolved organic matter optical properties (absorption and fluorescence) in 11 transparent lakes located above tree line in the Sierra Nevada Mountains (Spain), and we assessed potential external (evaporation and atmospheric deposition) and internal (bacterial abundance, bacterial production, chlorophyll a, and catchment vegetation) drivers of DOM patterns. At spatial and temporal scales, bacteria were related to chromophoric DOM (CDOM). At the temporal scale, water soluble organic carbon (WSOC) in dust deposition and evaporation were found to have a significant influence on DOC and CDOM in two Sierra Nevada lakes studied during the ice-free periods of 2000–2002. DOC concentrations and absorption coefficients at 320 nm were strongly correlated over the spatial scale (n = 11, R2 = 0.86; p < 0.01), but inconsistently correlated over time, indicating seasonal and interannual variability in external factors and a differential response of DOC concentration and CDOM to these factors. At the continental scale, higher mean DOC concentrations and more CDOM in lakes of the Sierra Nevada than in lakes of the Pyrenees and Alps may be due to a combination of more extreme evaporation, and greater atmospheric dust deposition. PMID:20582227

Chemical and biological survey of lakes and streams located in the Emerald Lake watershed, Sequoia National Park. Final report, July 1984-July 1986

DOE Office of Scientific and Technical Information (OSTI.GOV)

Melack, J.M.; Cooper, S.D.; Holmes, R.W.

1987-02-18

To investigate the effects or potential effects of acidification on Sierran aquatic habitats, the authors are conducting research on Emerald Lake and its inlet and outlet streams, in Sequoia National Park, California. Emerald Lake was chosen as the focus of the authors studies because it is representative of subalpine and alpine waters in the Sierra Nevada, and is located in the southwestern Sierra where acidic inputs are likely to be greater than in other areas of the Sierra Nevada. The investigations consist of two approaches: (1) A chemical and biological monitoring program and sediment analyses to provide the time seriesmore » needed to distinguish the effects of anthropogenic disturbance from natural variation; and (2) experimental investigations to examine the sensitivity of aquatic communities to acidic inputs and to predict the responses of aquatic communities to increased acidification. The research reported here began in June 1984 and continued through July 1986.« less

Diversity and Abundance of Ice Nucleating Strains of Pseudomonas syringae in a Freshwater Lake in Virginia, USA.

PubMed

Pietsch, Renée B; Vinatzer, Boris A; Schmale, David G

2017-01-01

The bacterium Pseudomonas syringae is found in a variety of terrestrial and aquatic environments. Some strains of P. syringae express an ice nucleation protein (hereafter referred to as Ice+) allowing them to catalyze the heterogeneous freezing of water. Though P. syringae has been sampled intensively from freshwater sources in France, little is known about the genetic diversity of P. syringae in natural aquatic habitats in North America. We collected samples of freshwater from three different depths in Claytor Lake, Virginia, USA between November 2015 and June 2016. Samples were plated on non-selective medium (TSA) and on medium selective for Pseudomonas (KBC) and closely related species to estimate the total number of culturable bacteria and of Pseudomonas , respectively. A droplet freezing assay was used to screen colonies for the Ice+ phenotype. Ice+ colonies were then molecularly identified based on the cts (citrate synthase) gene and the 16S rDNA gene. Phylogenetic analysis of cts sequences showed a surprising diversity of phylogenetic subgroups of P. syringae . Frequencies of Ice+ isolates on P. syringae selective medium ranged from 0 to 15% per sample with the highest frequency being found in spring. Our work shows that freshwater lakes can be a significant reservoir of Ice+ P. syringae . Future work is needed to determine the contribution of P. syringae from freshwater lakes to the P. syringae populations present in the atmosphere and on plants and, in particular, if freshwater lakes could be an inoculum source of P. syringae -caused plant disease outbreaks.

Patterns in Benthic Biodiversity Link Lake Trophic Status to Structure and Potential Function of Three Large, Deep Lakes

PubMed Central

Hayford, Barbara L.; Caires, Andrea M.; Chandra, Sudeep; Girdner, Scott F.

2015-01-01

Relative to their scarcity, large, deep lakes support a large proportion of the world’s freshwater species. This biodiversity is threatened by human development and is in need of conservation. Direct comparison of biodiversity is the basis of biological monitoring for conservation but is difficult to conduct between large, insular ecosystems. The objective of our study was to conduct such a comparison of benthic biodiversity between three of the world’s largest lakes: Lake Tahoe, USA; Lake Hövsgöl, Mongolia; and Crater Lake, USA. We examined biodiversity of common benthic organism, the non-biting midges (Chironomidae) and determined lake trophic status using chironomid-based lake typology, tested whether community structure was similar between the three lakes despite geographic distance; and tested whether chironomid diversity would show significant variation within and between lakes. Typology analysis indicated that Lake Hövsgöl was ultra-oligotrophic, Crater Lake was oligotrophic, and Lake Tahoe was borderline oligotrophic/mesotrophic. These results were similar to traditional pelagic measures of lake trophic status for Lake Hövsgöl and Crater Lake but differed for Lake Tahoe, which has been designated as ultra-oligotrophic by traditional pelagic measures such as transparency found in the literature. Analysis of similarity showed that Lake Tahoe and Lake Hövsgöl chironomid communities were more similar to each other than either was to Crater Lake communities. Diversity varied between the three lakes and spatially within each lake. This research shows that chironomid communities from these large lakes were sensitive to trophic conditions. Chironomid communities were similar between the deep environments of Lake Hövsgöl and Lake Tahoe, indicating that chironomid communities from these lakes may be useful in comparing trophic state changes in large lakes. Spatial variation in Lake Tahoe’s diversity is indicative of differential response of chironomid

How Physical Processes are Informing River Management Actions at Marble Bluff Dam, Truckee River, Nevada

NASA Astrophysics Data System (ADS)

Bountry, J.; Godaire, J.; Bradley, D. N.

2017-12-01

At the terminus of the Truckee River into Pyramid Lake (Nevada, USA), upstream river management actions have dramatically reshaped the river landscape, posing significant challenges for the management of endangered aquatic species and maintenance of existing infrastructure. Within the last 100 years, upstream water withdrawal for human uses has resulted in a rapid lowering of Pyramid Lake which initiated up to 90 ft of channel incision. In 1976 Marble Bluff Dam was constructed to halt the upstream progression of channel incision and protect upstream agricultural lands, tribal resources, and infrastructure. Since construction an additional 40 ft of lake lowering and subsequent channel lowering now poses a potential risk to the structural integrity of the dam. The dynamic downstream river combined with ongoing reservoir sedimentation pose challenges to fish passage facilities that enable migration of numerous endangered cui-ui and threatened Lahontan Cutthroat Trout (LCT) to upstream spawning areas each year. These facilities include a fish lock at the dam, a fish bypass channel which allows fish to avoid the shallow delta area during low lake levels, and a meandering channel constructed by the Nature Conservancy to connect the bypass channel to the receding Pyramid Lake. The reservoir formed by Marble Bluff Dam has completely filled with sediment which impacts fish passage facilities. The original operating manual for the dam recommends year-round flushing of sediment through radial gates, but this can no longer be accomplished. During critical fish migration periods in the spring operators must ensure fish entrance channels downstream of the dam are not buried with released sediment and fish are not trapped in a portion of the reservoir full of sediment that would risk sending them back over the dam. To help inform future reservoir sediment and infrastructure management strategies, we bracket a range of potential river responses to lake level lowering and floods

Onset and Multiple Fluctuations of Holocene Glaciation in the Sierra Nevada, California

NASA Astrophysics Data System (ADS)

Bowerman, N. D.; Clark, D. H.

2004-12-01

Multiple sediment cores from two paternoster tarns (First and Second lakes) in North Fork Big Pine Creek, Sierra Nevada, preserve the most detailed and complete record of Holocene glaciation yet recovered in the range; they indicate that the glacier was absent during the early Holocene, reformed in the late Holocene, and experienced several expansions and contractions, culminating with the Matthes maximum during the last ˜200 years. The lakes are fed by outwash from the Palisade Glacier, the largest ( ˜1.3 km2) and presumably longest-lived glacier in the Sierra Nevada, and capture essentially all of the rock flour produced by the glacier. Distinct late-Holocene (Matthes) and late-Pleistocene (Recess Peak) moraines lie between the modern glacier and the lakes. Thus, the lakes have received continuous sedimentation since the retreat of the Tioga glacier ( ˜15,000 yr B.P.), and therefore capture rock flour related to all subsequent advances. First and Second lakes occupy relatively deep bedrock basins at 3036 m and 3066 m asl., respectively. Third Lake, a shallow (<3 m deep), moraine-dammed lake that lies directly above Second Lake, is the only lake between the Palisade Glacier and the lower lakes. As such, it captures the coarsest (sand/gravel bedload) outwash, but abundant suspended sediment (silt/clay) continues to the lower lakes. We cored the lakes using both Reasoner and Livingston corers, to sediment depths of up to ˜5 m. The deepest cores bottomed in coarse, inorganic sand and silt that we interpret as outwash or slopewash related to Tioga deglaciation. Magnetic susceptibility (MS) analyses of the sediment cores indicate that both lakes record multiple late-Holocene peaks in MS, with the most recent peak being the largest. They also retain outwash near the base related to the more extensive Recess Peak advance. MS peaks in Sierran lakes typically indicate greater abundances of clastic (vs. organic) sediment. The peaks in our cores thus imply 4-5 periods of

Geochronology and paleoenvironment of pluvial Harper Lake, Mojave Desert, California, USA

USGS Publications Warehouse

Garcia, Anna L.; Knott, Jeffrey R.; Mahan, Shannon; Bright, Jordan

2014-01-01

Accurate reconstruction of the paleo-Mojave River and pluvial lake (Harper, Manix, Cronese, and Mojave) system of southern California is critical to understanding paleoclimate and the North American polar jet stream position over the last 500 ka. Previous studies inferred a polar jet stream south of 35°N at 18 ka and at ~ 40°N at 17–14 ka. Highstand sediments of Harper Lake, the upstream-most pluvial lake along the Mojave River, have yielded uncalibrated radiocarbon ages ranging from 24,000 to > 30,000 14C yr BP. Based on geologic mapping, radiocarbon and optically stimulated luminescence dating, we infer a ~ 45–40 ka age for the Harper Lake highstand sediments. Combining the Harper Lake highstand with other Great Basin pluvial lake/spring and marine climate records, we infer that the North American polar jet stream was south of 35°N about 45–40 ka, but shifted to 40°N by ~ 35 ka. Ostracodes (Limnocythere ceriotuberosa) from Harper Lake highstand sediments are consistent with an alkaline lake environment that received seasonal inflow from the Mojave River, thus confirming the lake was fed by the Mojave River. The ~ 45–40 ka highstand at Harper Lake coincides with a shallowing interval at downstream Lake Manix.

DISTRIBUTIONS OF AIRBORNE AGRICULTURAL CONTAMINANTS RELATIVE TO AMPHIBIAN POPULATIONS IN THE SOUTHERN SIERRA NEVADA, CA

EPA Science Inventory

The Sierra Nevada mountain range lies adjacent to one of the heaviest pesticide use areas in the USA, the Central Valley of California. Because of this proximity, concern has arisen that agricultural pesticides, in addition to other contaminants, are adversely affecting the natur...

Airborne radar imaging of subaqueous channel evolution in Wax Lake Delta, Louisiana, USA

NASA Astrophysics Data System (ADS)

Shaw, John B.; Ayoub, Francois; Jones, Cathleen E.; Lamb, Michael P.; Holt, Benjamin; Wagner, R. Wayne; Coffey, Thomas S.; Chadwick, J. Austin; Mohrig, David

2016-05-01

Shallow coastal regions are among the fastest evolving landscapes but are notoriously difficult to measure with high spatiotemporal resolution. Using Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) data, we demonstrate that high signal-to-noise L band synthetic aperture radar (SAR) can reveal subaqueous channel networks at the distal ends of river deltas. Using 27 UAVSAR images collected between 2009 and 2015 from the Wax Lake Delta in coastal Louisiana, USA, we show that under normal tidal conditions, planform geometry of the distributary channel network is frequently resolved in the UAVSAR images, including ~700 m of seaward network extension over 5 years for one channel. UAVSAR also reveals regions of subaerial and subaqueous vegetation, streaklines of biogenic surfactants, and what appear to be small distributary channels aliased by the survey grid, all illustrating the value of fine resolution, low noise, L band SAR for mapping the nearshore subaqueous delta channel network.

Recent ecological and biogeochemical changes in alpine lakes of Rocky Mountain National Park (Colorado, USA): A response to anthropogenic nitrogen deposition

USGS Publications Warehouse

Wolfe, A.P.; Van Gorp, A.C.; Baron, Jill S.

2003-01-01

Dated sediment cores from five alpine lakes (>3200 m asl) in Rocky Mountain National Park (Colorado Front Range, USA) record near-synchronous stratigraphic changes that are believed to reflect ecological and biogeochemical responses to enhanced nitrogen deposition from anthropogenic sources. Changes in sediment proxies include progressive increases in the frequencies of mesotrophic planktonic diatom taxa and diatom concentrations, coupled with depletions of sediment δ15N and C : N values. These trends are especially pronounced since approximately 1950. The most conspicuous diatoms to expand in recent decades are Asterionella formosa and Fragilaria crotonensis. Down-core species changes are corroborated by a year-long sediment trap experiment from one of the lakes, which reveals high frequencies of these two taxa during autumn and winter months, the interval of peak annual limnetic [NO3-]. Although all lakes record recent changes, the amplitude of stratigraphic shifts is greater in lakes east of the Continental Divide relative to those on the western slope, implying that most nitrogen enrichment originates from urban, industrial and agricultural sources east of the Rocky Mountains. Deviations from natural trajectories of lake ontogeny are illustrated by canonical correspondence analysis, which constrains the diatom record as a response to changes in nitrogen biogeochemistry. These results indicate that modest rates of anthropogenic nitrogen deposition are fully capable of inducing directional biological and biogeochemical shifts in relatively pristine ecosystems.

POPS IN ALLIGATOR LIVERS FROM LAKE APOPKA, FLORIDA, USA

EPA Science Inventory

Reproductive disorders in American alligators (Alligator mississippiensis) inhabiting Lake Apopka, Florida, have been observed for several years. Such disorders are hypothesized to be caused by endocrine disrupting contaminants occurring in the Lake due to pesticide spills and ...

Population dynamics of the Cui-ui of Pyramid Lake, Nevada: a Potamodromous catostomid subject to failed reproduction

USGS Publications Warehouse

Scoppettone, Gayton G.; Rissler, Peter H.; Fabes, Mark C.; Shea, Sean P.

2015-01-01

Fishes of the Truckee River basin (California and Nevada) evolved in an aquatic system that has been episodically diminished by extended drought. For potamodromous species, such as the endangered Cui-ui endemic to Pyramid Lake, Nevada, prehistoric episodic severe drought presumably led to periods of failed reproduction due to restricted access to spawning habitat. The response of the Cui-ui population to more recent failed reproduction caused by anthropogenic activity was studied to learn how to manage this species through periods of spawning disruption. Adult Cui-ui survival averaged 91% and 89% for females and males, respectively, in drought years when spawning migrations were either precluded or few fish migrated because of no or low stream flow. In each of 2 years when stream access was precluded, the adult survival was nearly 100% suggesting that Cui-ui survival is extended in the absence of a spawning migration. Survival averaged 62% and 60% for females and males, respectively, in years of spawning migrations. Strong predominant year-classes developed in the year immediately following a period of failed reproduction, indicating the species’ capacity for population rebound. Year-class predominance persisted for 6–10 years and through years of low survival associated with migration years, and this predominance is probably due, in part, to a diverse age at maturity. Contemporary water diversions from the Truckee River provided the opportunity to study the response of the Cui-ui population to years of failed reproduction. A projected drier Truckee River basin associated with global climate change will test the Cui-ui’s adaptive capacity to endure periods of reproductive failure. This study is aimed at assisting Cui-ui managers in conserving the species in this highly regulated and changing system. The study also adds insight into the prehistoric population dynamics of a potamodromous species in the arid western United States subject to wide fluctuations in

Estimates of evapotranspiration from the Ruby Lake National Wildlife Refuge area, Ruby Valley, northeastern Nevada, May 1999-October 2000

USGS Publications Warehouse

Berger, David L.; Johnson, Michael J.; Tumbusch, Mary L.; Mackay, Jeffrey

2001-01-01

The Ruby Lake National Wildlife Refuge in Ruby Valley, Nevada, contains the largest area of perennial wetlands in northeastern Nevada and provides habitat to a large number of migratory and nesting waterfowl. The long-term preservation of the refuge depends on the availability of sufficient water to maintain optimal habitat conditions. In the Ruby Valley water budget, evapotranspiration (ET) from the refuge is one of the largest components of natural outflow. To help determine the amount of inflow needed to maintain wetland habitat, estimates of ET for May 1999 through October 2000 were made at major habitats throughout the refuge. The Bowen-ratio method was used to estimate daily ET at four sites: over open water, in a moderate-to-dense cover of bulrush marsh, in a moderate cover of mixed phreatophytic shrubs, and in a desert-shrub upland. The eddy-correlation method was used to estimate daily ET for periods of 2 to 12 weeks at a meadow site and at four sites in a sparse-to-moderate cover of phreatophytic shrubs. Daily ET rates ranged from less than 0.010 inch per day at all of the sites to a maximum of 0.464 inch per day at the open-water site. Average daily ET rates estimated for open water and a bulrush marsh were about four to five times greater than in areas of mixed phreatophytic shrubs, where the depth to ground water is less than 5 feet. Based on the seasonal distribution of major habitats in the refuge and on winter and summer ET rates, an estimated total of about 89,000 acre-feet of water was consumed by ET during October 1999-September 2000 (2000 water year). Of this total, about 49,800 acre-feet was consumed by ET in areas of open water and bulrush marsh.

Recent faulting in western Nevada revealed by multi-scale seismic reflection

USGS Publications Warehouse

Frary, Roxanna N.; Louie, John N.; Stephenson, William J.; Odum, Jackson K.; Kell, Annie; Eisses, Amy; Kent, Graham M.; Driscoll, Neal W.; Karlin, Robert; Baskin, Robert L.; Pullammanappallil, Satish; Liberty, Lee M.

2011-01-01

The main goal of this study is to compare different reflection methods used to image subsurface structure within different physical environments in western Nevada. With all the methods employed, the primary goal is fault imaging for structural information toward geothermal exploration and seismic hazard estimation. We use seismic CHIRP (a swept-frequency marine acquisition system), weight drop (an accelerated hammer source), and two different vibroseis systems to characterize fault structure. We focused our efforts in the Reno metropolitan area and the area within and surrounding Pyramid Lake in northern Nevada. These different methods have provided valuable constraints on the fault geometry and activity, as well as associated fluid movement. These are critical in evaluating the potential for large earthquakes in these areas, and geothermal exploration possibilities near these structures.

Recent faulting in western Nevada revealed by multi-scale seismic reflection

USGS Publications Warehouse

Frary, R.N.; Louie, J.N.; Stephenson, W.J.; Odum, J.K.; Kell, A.; Eisses, A.; Kent, G.M.; Driscoll, N.W.; Karlin, R.; Baskin, R.L.; Pullammanappallil, S.; Liberty, L.M.

2011-01-01

The main goal of this study is to compare different reflection methods used to image subsurface structure within different physical environments in western Nevada. With all the methods employed, the primary goal is fault imaging for structural information toward geothermal exploration and seismic hazard estimation. We use seismic CHIRP a swept-frequency marine acquisition system, weight drop an accelerated hammer source, and two different vibroseis systems to characterize fault structure. We focused our efforts in the Reno metropolitan area and the area within and surrounding Pyramid Lake in northern Nevada. These different methods have provided valuable constraints on the fault geometry and activity, as well as associated fluid movement. These are critical in evaluating the potential for large earthquakes in these areas, and geothermal exploration possibilities near these structures. ?? 2011 Society of Exploration Geophysicists.

Length-weight relationship and a relative condition factor equation for lake sturgeon (Acipenser fulvescens) from the St Clair River system (Michigan, USA)

USGS Publications Warehouse

Craig, J.M.; Thomas, M.V.; Nichols, S.J.

2005-01-01

Several USA state, federal, and Canadian agencies study lake sturgeon (Acipenser fulvescens) within the St Clair River and Lake St Clair, collectively referred to hereafter as the St Clair River (SCR) system. Previously, there has been no set standard for determining condition for SCR system lake sturgeon. Condition measures the variation from the expected weight for length as an indicator of fatness, general well-being, gonad development, etc. The aim of this project was to determine the length weight relationship of lake sturgeon caught from the SCR system, from which a relative condition factor (Kn) equation could be derived. Total length (TL, mm) and weight (W, kg) were measured for 1074 lake sturgeon (101 males and 16 females were identifiable) collected by setline and bottom trawl from the SCR system in May-September, 1997-2002. Analysis of covariance found no difference in the length-weight relationship between sampling gear or sex. Least-squares regression of log10W ?? log10TL produced the overall equation logW = 3.365logTL - 9.320. Using the exponential form of the slope and y-intercept, relative condition factor for lake sturgeon from the SCR system can be calculated as Kn - W/[(4.786 ?? 10-10)(TL3.365)]. Equations for males and females were also developed. Overall, body condition was significantly correlated with both age and girth; no significant difference in Kn by sex was found. In general, the SCR lake sturgeon population was near the upper ends of growth and condition ranges listed in the literature, comparable with those populations that are at similar latitudes. Although condition factors should be interpreted with caution, proper use of a standard equation provides a non-lethal measure of overall fish health that can be used by biologists and managers in ongoing efforts to restore lake sturgeon throughout the Great Lakes. ?? 2005 Blackwell Verlag, Berlin.

Length-weight relationship and a relative condition factor equation for lake sturgeon (Acipenser fulvescens) from the St. Clair River system (Michigan, USA)

USGS Publications Warehouse

Craig, Jaquelyn M.; Thomas, Michael V.; Nichols, S. Jerrine

2005-01-01

Several USA state, federal, and Canadian agencies study lake sturgeon (Acipenser fulvescens) within the St Clair River and Lake St Clair, collectively referred to hereafter as the St Clair River (SCR) system. Previously, there has been no set standard for determining condition for SCR system lake sturgeon. Condition measures the variation from the expected weight for length as an indicator of fatness, general well-being, gonad development, etc. The aim of this project was to determine the length-weight relationship of lake sturgeon caught from the SCR system, from which a relative condition factor (Kn) equation could be derived. Total length (TL, mm) and weight (W, kg) were measured for 1074 lake sturgeon (101 males and 16 females were identifiable) collected by setline and bottom trawl from the SCR system in May-September, 1997-2002. Analysis of covariance found no difference in the length-weight relationship between sampling gear or sex. Least-squares regression of log10W x log10TL produced the overall equation logW = 3.365logTL - 9.320. Using the exponential form of the slope and y-intercept, relative condition factor for lake sturgeon from the SCR system can be calculated as Kn = W/ [(4.786 x 10-10)(TL3.365)]. Equations for males and females were also developed. Overall, body condition was significantly correlated with both age and girth; no significant difference in Kn by sex was found. In general, the SCR lake sturgeon population was near the upper ends of growth and condition ranges listed in the literature, comparable with those populations that are at similar latitudes. Although condition factors should be interpreted with caution, proper use of a standard equation provides a non-lethal measure of overall fish health that can be used by biologists and managers in ongoing efforts to restore lake sturgeon throughout the Great Lakes.

Diet dynamics of the juvenile piscivorous fish community in Spirit Lake, Iowa, USA, 1997-1998

USGS Publications Warehouse

Pelham, M.E.; Pierce, C.L.; Larscheid, J.G.

2001-01-01

We assessed temporal dynamics and variation among species and age-classes in the diets of age 0 and age 1 piscivorous fish species in Spirit Lake, Iowa, USA during 1997 and 1998. Species included walleye Stizostedion vitreum, yellow perch Perca flavescens, smallmouth bass Micropterus dolomieui, largemouth bass Micropterus salmoides, black crappie Pomoxis nigromaculatus and white bass Morone chrysops. Thirty taxa were identified in diets, including 12 species of fish. We found dramatic differences in diets among species, among age-classes within species and over time. Walleye, largemouth bass, smallmouth bass and white bass were piscivorous at age 0. Black crappie began piscivory at age 1. Yellow perch also began piscivory at age 1, but fish were a very small fraction of age-1 diets. The primary temporal pattern, seen in several species and age- classes, was an increase in piscivory from spring to fall. This pattern was due to the lack of small, age-0 prey fish in spring. Although some patterns were evident, the taxonomic composition of the diets of all species was highly variable over time, making generalizations difficult. A surprising result was the absence of yellow perch in the diet of age-0 walleye, despite their abundance in Spirit Lake and prominence in diets of age-1 walleye and other age 1-piscivores. Age-0 yellow perch were consistently too large to be eaten by age-0 piscivores, which preyed primarily on invertebrates and smaller fish such as johnny darters Etheostoma nigrum and age 0 bluegill Lepomis macrochirus. This finding suggests that predator-prey interactions and resulting population dynamics may be quite different in Spirit Lake than in other systems dominated by walleye and yellow perch.

DINKEY LAKES ROADLESS AREA, CALIFORNIA.

USGS Publications Warehouse

Dodge, F.C.W.; Federspiel, F.E.

1984-01-01

The Dinkey Lakes Roadless Area occupies an area of about 184 sq mi on the western slope of the Sierra Nevada, California. The results of a mineral survey show that parts of the area have substantiated resource potential for tungsten and marble and probable resource potential for quartz crystal gemstones. A probable resource potential for geothermal energy exists in one small area. No potential for other metallic mineral or energy resources was identified in this study.

Critical nitrogen deposition loads in high-elevation lakes of the western US inferred from paleolimnological records

USGS Publications Warehouse

Saros, J.E.; Clow, D.W.; Blett, T.; Wolfe, A.P.

2011-01-01

Critical loads of nitrogen (N) from atmospheric deposition were determined for alpine lake ecosystems in the western US using fossil diatom assemblages in lake sediment cores. Changes in diatom species over the last century were indicative of N enrichment in two areas, the eastern Sierra Nevada, starting between 1960 and 1965, and the Greater Yellowstone Ecosystem, starting in 1980. In contrast, no changes in diatom community structure were apparent in lakes of Glacier National Park. To determine critical N loads that elicited these community changes, we modeled wet nitrogen deposition rates for the period in which diatom shifts first occurred in each area using deposition data spanning from 1980 to 2007. We determined a critical load of 1.4 kg N ha-1 year-1 wet N deposition to elicit key nutrient enrichment effects on diatom communities in both the eastern Sierra Nevada and the Greater Yellowstone Ecosystem. ?? 2010 Springer Science+Business Media B.V.

Investigations of the Effects of Synthetic Chemicals on the Endocrine System of Common Carp in Lake Mead, Nevada and Arizona

USGS Publications Warehouse

Rosen, Michael R.; Goodbred, Steven L.; Patiño, Reynaldo; Leiker, Thomas A.; Orsak, Erik

2006-01-01

Introduction: Lake Mead is the largest reservoir by volume in the United States and was created by the construction of the 221-meter high Hoover Dam in 1935 at Black Canyon on the lower Colorado River between Nevada and Arizona (fig. 1). Inflows of water into the lake include three rivers, Colorado, Virgin, and Muddy; as well as Las Vegas Wash, which is now perennial because of discharges from municipal wastewater treatment plants (Covay and Leiker, 1998) and urban stormwater runoff. As the population within the Las Vegas Valley began to increase in the 1940s, the treated effluent volume also has increased and in 1993 it constituted about 96 percent of the annual discharge of Las Vegas Wash (Bevans and others, 1996). The mean flow of Las Vegas Wash into Las Vegas Bay from 1992 to 1998 was about 490,000 m3/d (Preissler and others, 1999) and in 2001 increased to 606,000 m3/d (U.S. Bureau of Reclamation, 2001). The nutrient concentration in most areas of the lake is low, but wastewater discharged into Las Vegas Bay has caused an increased level of nutrients and primary productivity (aquatic plant and algal production) in this area of the lake (LaBounty and Horn, 1997). A byproduct of this increase in productivity has been the establishment of an important recreational fishery in Las Vegas Bay. However, concentrations of chlorophyll a (a measure of algal biomass) have also increased (LaBounty and Horn, 1997). In the spring of 2001, parts of Lake Mead experienced massive algal blooms. In addition to nutrient loading by wastewater, the presence of numerous synthetic chemicals in water, bottom sediments, and in fish tissue also has been reported (Bevans and others, 1996). Synthetic chemicals discharging into Las Vegas Bay and Lake Mead (fig. 1) originate from several sources that include surplus residential-irrigation water runoff, stormwater runoff, subsurface inflow, and tertiary treated sewage effluent discharging from three sewage-treatment plants. Chemicals detected

Ikaite precipitation by mixing of shoreline springs and lake water, Mono Lake, California, USA

NASA Astrophysics Data System (ADS)

Bischoff, James L.; Stine, Scott; Rosenbauer, Robert J.; Fitzpatrick, John A.; Stafford, Thomas W., Jr.

1993-08-01

Metastable ikaite (CaCO 3·6H 2O) forms abundantly during winter months along the south shoreline of Mono Lake where shoreline springs mix with lake water. Ikaite precipitates because of its decreased solubility at low temperature and because of orthophosphate-ion inhibition of calcite and aragonite. During the spring some of the ikaite is transformed to anhydrous CaCO 3 and is incorporated into tufa, but most is dispersed by wave action into the lake where it reacts to form gaylussite (Na 2Ca(CO 3) 2· 5H 2O). Spring waters have low pH values, are dominantly Ca-Na-HCO 3, have low radiocarbon activities, and are mixtures of deep-seated geothermal and cold groundwaters. Chemical modeling reveals that precipitation of CaCO 3 can occur over a broad range of mixtures of spring and lake water with a maximum production occurring at 96% spring water and 4% lake water. Under these conditions all the Ca and a significant fraction of the CO 3 of the precipitate is spring supplied. A radiocarbon age of 19,580 years obtained on a natural ikaite sample supports this conclusion. With the springs supplying a large and probably variable portion of the carbonate, and with apparent 14C age of the carbonate varying from spring to spring, tufa of similar actual antiquity may yield significantly different 14C dates, making tufa at this location unsuitable for absolute age dating by the radiocarbon method.

Ikaite precipitation by mixing of shoreline springs and lake water, Mono Lake, California, USA

USGS Publications Warehouse

Bischoff, J.L.; Stine, S.; Rosenbauer, R.J.; Fitzpatrick, J.A.; Stafford, Thomas W.

1993-01-01

Metastable ikaite (CaCO3??6H2O) forms abundantly during winter months along the south shoreline of Mono Lake where shoreline springs mix with lake water. Ikaite precipitates because of its decreased solubility at low temperature and because of orthophosphate-ion inhibition of calcite and aragonite. During the spring some of the ikaite is transformed to anhydrous CaCO3 and is incorporated into tufa, but most is dispersed by wave action into the lake where it reacts to form gaylussite (Na2Ca(CO3)2?? 5H2O). Spring waters have low pH values, are dominantly Ca-Na-HCO3, have low radiocarbon activities, and are mixtures of deep-seated geothermal and cold groundwaters. Chemical modeling reveals that precipitation of CaCO3 can occur over a broad range of mixtures of spring and lake water with a maximum production occurring at 96% spring water and 4% lake water. Under these conditions all the Ca and a significant fraction of the CO3 of the precipitate is spring supplied. A radiocarbon age of 19,580 years obtained on a natural ikaite sample supports this conclusion. With the springs supplying a large and probably variable portion of the carbonate, and with apparent 14C age of the carbonate varying from spring to spring, tufa of similar actual antiquity may yield significantly different 14C dates, making tufa at this location unsuitable for absolute age dating by the radiocarbon method. ?? 1993.

Metatranscriptomic analysis of prokaryotic communities active in sulfur and arsenic cycling in Mono Lake, California, USA.

PubMed

Edwardson, Christian F; Hollibaugh, James T

2017-10-01

This study evaluates the transcriptionally active, dissimilatory sulfur- and arsenic-cycling components of the microbial community in alkaline, hypersaline Mono Lake, CA, USA. We sampled five depths spanning the redox gradient (10, 15, 18, 25 and 31 m) during maximum thermal stratification. We used custom databases to identify transcripts of genes encoding complex iron-sulfur molybdoenzyme (CISM) proteins, with a focus on arsenic (arrA, aioA and arxA) and sulfur cycling (dsrA, aprA and soxB), and assigned them to taxonomic bins. We also report on the distribution of transcripts related to the ars arsenic detoxification pathway. Transcripts from detoxification pathways were not abundant in oxic surface waters (10 m). Arsenic cycling in the suboxic and microaerophilic zones of the water column (15 and 18 m) was dominated by arsenite-oxidizing members of the Gammaproteobacteria most closely affiliated with Thioalkalivibrio and Halomonas, transcribing arxA. We observed a transition to arsenate-reducing bacteria belonging to the Deltaproteobacteria and Firmicutes transcribing arsenate reductase (arrA) in anoxic bottom waters of the lake (25 and 31 m). Sulfur cycling at 15 and 18 m was dominated by Gammaproteobacteria (Thioalkalivibrio and Thioalkalimicrobium) oxidizing reduced S species, with a transition to sulfate-reducing Deltaproteobacteria at 25 and 31 m. Genes related to arsenic and sulfur oxidation from Thioalkalivibrio were more highly transcribed at 15 m relative to other depths. Our data highlight the importance of Thioalkalivibrio to arsenic and sulfur biogeochemistry in Mono Lake and identify new taxa that appear capable of transforming arsenic.

Site fidelity of the declining amphibian Rana sierrae (Sierra Nevada yellow-legged frog)

Treesearch

Kathleen Matthews; Haiganoush Preisler

2010-01-01

From 1997 to 2006, we used mark–recapture models to estimate the site fidelity of 1250 Sierra Nevada yellow-legged frogs (Rana sierrae) in Kings Canyon National Park, California, USA, during their three main activity periods of overwintering, breeding, and feeding. To quantify site fidelity, the tendency to return to and reuse previously occupied...

3-Dimensional Geologic Modeling Applied to the Structural Characterization of Geothermal Systems: Astor Pass, Nevada, USA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siler, Drew L; Faulds, James E; Mayhew, Brett

2013-04-16

Geothermal systems in the Great Basin, USA, are controlled by a variety of fault intersection and fault interaction areas. Understanding the specific geometry of the structures most conducive to broad-scale geothermal circulation is crucial to both the mitigation of the costs of geothermal exploration (especially drilling) and to the identification of geothermal systems that have no surface expression (blind systems). 3-dimensional geologic modeling is a tool that can elucidate the specific stratigraphic intervals and structural geometries that host geothermal reservoirs. Astor Pass, NV USA lies just beyond the northern extent of the dextral Pyramid Lake fault zone near the boundarymore » between two distinct structural domains, the Walker Lane and the Basin and Range, and exhibits characteristics of each setting. Both northwest-striking, left-stepping dextral faults of the Walker Lane and kinematically linked northerly striking normal faults associated with the Basin and Range are present. Previous studies at Astor Pass identified a blind geothermal system controlled by the intersection of west-northwest and north-northwest striking dextral-normal faults. Wells drilled into the southwestern quadrant of the fault intersection yielded 94°C fluids, with geothermometers suggesting a maximum reservoir temperature of 130°C. A 3-dimensional model was constructed based on detailed geologic maps and cross-sections, 2-dimensional seismic data, and petrologic analysis of the cuttings from three wells in order to further constrain the structural setting. The model reveals the specific geometry of the fault interaction area at a level of detail beyond what geologic maps and cross-sections can provide.« less

Thermal regimes and snowpack relations of periglacial talus slopes, Sierra Nevada, California, USA.

Treesearch

Constance I Millar; Robert D. Westfall; Diane L. Delany

2014-01-01

Thermal regimes of eight periglacial talus slopes, at contrasting elevations, aspects, and substrates, in the Sierra Nevada, California, had complex microclimatic patterns partially decoupled from external conditions. Over three years, warm seasons showed mean talus matrix temperatures and daily variances lower than surfaces and cooler than free-air; talus surface and...

Multi-tracer investigation of groundwater residence time in a karstic aquifer: Bitter Lakes National Wildlife Refuge, New Mexico, USA

NASA Astrophysics Data System (ADS)

Land, Lewis; Huff, G. F.

2010-03-01

Several natural and anthropogenic tracers have been used to evaluate groundwater residence time within a karstic limestone aquifer in southeastern New Mexico, USA. Natural groundwater discharge occurs in the lower Pecos Valley from a region of karst springs, wetlands and sinkhole lakes at Bitter Lakes National Wildlife Refuge, on the northeast margin of the Roswell Artesian Basin. The springs and sinkholes are formed in gypsum bedrock that serves as a leaky confining unit for an artesian aquifer in the underlying San Andres limestone. Because wetlands on the Refuge provide habitat for threatened and endangered species, there is concern about the potential for contamination by anthropogenic activity in the aquifer recharge area. Estimates of the time required for groundwater to travel through the artesian aquifer vary widely because of uncertainties regarding karst conduit flow. A better understanding of groundwater residence time is required to make informed decisions about management of water resources and wildlife habitat at Bitter Lakes. Results indicate that the artesian aquifer contains a significant component of water recharged within the last 10-50 years, combined with pre-modern groundwater originating from deeper underlying aquifers, some of which may be indirectly sourced from the high Sacramento Mountains to the west.

Multi-Tracer Investigation of Groundwater Residence Time in a Karstic Aquifer: Bitter Lakes National Wildlife Refuge, New Mexico, USA

NASA Astrophysics Data System (ADS)

Land, L. A.; Huff, R.

2009-12-01

Several natural and anthropogenic tracers are used to evaluate groundwater residence time within the karstic limestone aquifer of the Roswell Artesian Basin, southeastern New Mexico, USA. Natural groundwater discharge occurs in the lower Pecos Valley from a region of karst springs, wetlands and sinkhole lakes at Bitter Lakes National Wildlife Refuge. The springs and sinkholes are formed in gypsum bedrock that serves as a leaky confining unit for an artesian aquifer in the underlying San Andres limestone. Because wetlands on the Refuge provide habitat for a number of threatened and endangered species, Refuge managers have expressed concern about the potential for contamination by anthropogenic activity in the aquifer recharge area. Estimates of the time required for groundwater to travel through the artesian aquifer vary widely because of uncertainties regarding the role of karst conduit flow. A better understanding of groundwater residence time is thus required to make informed decisions about management of water resources and wildlife habitat at Bitter Lakes. Results of tracer investigations indicate that the artesian aquifer contains a significant component of water recharged within the last 10 to 50 years, combined with pre-modern groundwater originating from deeper underlying aquifers, some of which may be indirectly sourced from the high Sacramento Mountains to the west.

Lithospheric extension near Lake Mead, Nevada - A model for ductile flow in the lower crust

NASA Technical Reports Server (NTRS)

Kruse, Sarah; Mcnutt, Marcia; Phipps-Morgan, Jason; Royden, Leigh

1991-01-01

Small variations in gravity anomalies and topographic elevation observed in areas that have undergone highly variable amounts of upper crustal thinning can be satisfactorily explained by ductile flow of lower crustal material under the proper conditions. The boundary between the unextended Colorado Plateau and a strongly extended domain in the Basin and Range Province in the Lake Mead (Nevada) region is examined. Finite element modeling of Newtonian flow and power law creep shows that flow over the length scale of the eastern Basin and Range (500) km or more) corresponding to upper crustal extension by a factor of 1.4-3 over 10 million years requires effective viscosities less than 10 to the 18th - 10 to the 20th Pa s for ductile channels 10-25 km thick. Modeling suggests that these effective viscosities may be sustained by lower crustal material deforming at laboratory-derived power law creep rates. The longer-scale flow may require elevated crustal temperatures (more than 700 C), depending on the composition and material properties assumed. Under the boundary conditions assumed in this study the linear viscous flow models yield a satisfactory approximation to deformation by power law creep. This work suggests that flow in the lower crust may be a viable mechanism for producing small variations in total crustal thickness between strongly extended and less extended regions, and thereby explaining the relative uniformity in gravity and topography between such regions.

Water-related scientific activities of the U.S. Geological Survey in Nevada, fiscal years 1993-94

USGS Publications Warehouse

Foglesong, M. Teresa

1995-01-01

The U.S. Geological Survey has been collecting water-resources data in Nevada since 1890. Most of the projects that constitute the current Nevada District program can be classified as either basic- data acquisition (about 25 percent) or hydrologic interpretation (about 75 percent). About 39 percent of the activities are supported by cooperative agreements with State and local agencies. Technical projects supported by other Federal agencies make up about 32 percent of the program, and the re- maining 29 percent consists of USGS data collection, interpretive projects, and research. Water con- ditions in most of Nevada during fiscal years 1993 and 1994 continued to be dry, a continuation of drought conditions since late 1986. The major water-resource issues in Nevada include: water allocation in the Truckee River and Carson River Basins; water-supply needs of Las Vegas and the Reno/Sparks area, including water-importation plans; hydrologic effects of weapons testing at the Nevada Test Site; assessment of potential long-term effects of the proposed Yucca Mountain Nuclear Waste Repository; and drought. Future water-resources issues in Nevada are likely to center on water supply for, and environmental effects of, the rapidly growing population centers at Las Vegas, Reno, and Elko; impacts of operations at the Nevada Test Site; management of interstate rivers such as the Truckee, Carson, Walker, and Colorado Rivers; hydrologic and environmental impacts at heavily mined areas; and water-quality management in the Lake Tahoe Basin.

Changes in lake levels, salinity and the biological community of Great Salt Lake (Utah, USA), 1847-1987

USGS Publications Warehouse

Stephens, D.W.

1990-01-01

Great Salt Lake is the fourth largest terminal lake in the world, with an area of about 6000 square kilometers at its historic high elevation. Since its historic low elevation of 1277.52 meters in 1963, the lake has risen to a new historic high elevation of 1283.77 meters in 1986-1987, a net increase of about 6.25 meters. About 60 percent of this increase, 3.72 meters, has occurred since 1982 in response to greater than average precipitation and less than average evaporation. Variations in salinity have resulted in changes in the composition of the aquatic biological community which consists of bacteria, protozoa, brine shrimp and brine flies. These changes were particularly evident following the completion of a causeway in 1959 which divided the lake. Subsequent salinities in the north part of the lake have ranged from 16 to 29 percent and in the south part from 6 to 28 percent. Accompanying the rise in lake elevation from 1982 to 1987 have been large decreases in salinity of both parts of the lake. This has resulted in changes in the biota from obligate halophiles, such as Dunaliella salina and D. viridis, to opportunistic forms such as a blue-green alga (Nodularia spumigena). The distribution and abundance of brine shrimp (Artemia salina) in the lake also have followed closely the salinity. In 1986, when the salinity of the south part of the lake was about 6 percent, a population of brackish-water killifish (Lucania parva) was observed along the shore near inflow from a spring. ?? 1990 Kluwer Academic Publishers.

Geology of Utah and Nevada by ERTS-1 imagery

NASA Technical Reports Server (NTRS)

Jensen, M. L.

1973-01-01

Repetitive ERTS-1 imagery covering Utah and Nevada is studied as an aid in structural geology, mineral exploration, and limnological and hydrological aspects. Limnological features of algal blooms and varying biological activities in Utah Lake and the Great Salt Lake are grossly evident on the imagery with more subtle details detected on the different bands. Major structural breaks, lineages, or trends are abundant throughout the area of study. The correlation of positive aeromagnetic anomalies with the trends suggests near surface intrusive bodies, not yet exposed at the surface, that can be tested for possible associated mineralization by collecting soil-gas at the surface which is analyzed for mercury that is (1) apparently associated with mineralization, (2) escapes as a vapor, and (3) can be readily measured in extremely low amounts of less than 1 ppb by absorption.

Preliminary analysis of the role of lake basin morphology on the modern diatom flora in the Ruby Mountains and East Humboldt Range, Nevada, USA

USGS Publications Warehouse

Starratt, Scott W.

2014-01-01

As paleolimnologists, we often look at the world through a 5-cm-diameter hole in the bottom of a lake, and although a number of studies have shown that a single core in the deepest part of a lake does not necessarily reflect the entire diatom flora, time and money often limit our ability to collect more than one core from a given site. This preliminary study is part of a multidisciplinary research project to understand Holocene climate variability in alpine regions of the Great Basin, and ultimately, to compare these high elevation records to the better studied pluvial records from adjacent valleys, in this case, the Ruby Valley.

Late Pleistocene to Holocene lake levels of Lake Warner, Oregon (USA) and their effect on archaeological site distribution patterns

NASA Astrophysics Data System (ADS)

Wriston, T.; Smith, G. M.

2017-12-01

Few chronological controls are available for the rise and fall of small pluvial lake systems in the Northwestern Great Basin. Within Warner Basin this control was necessary for interpretation of known archaeological sites and for predicting where evidence of its earliest inhabitants might be expected. We trenched along relic beach ridges of Lake Warner, surveyed a stratified sample of the area for archaeological sites, and excavated some sites and a nearby rockshelter. These efforts produced new ages that we used to construct a lake level curve for Lake Warner. We found that the lake filled the valley floor between ca. 30,000 cal yr BP and ca. 10,300 cal yr BP. In nearby basins, several oscillations are evident before ca. 21,100 cal yr BP, but a steep rise to the LGM maximum occurred between 21,000 and 20,000 cal yr BP. Lake Warner likely mirrored these changes, dropped to the valley floor ca. 18,340 cal yr BP, and then rose to its maximum highstand when its waters briefly reached 1454 m asl. After this highstand the lake receded to moderately high levels. Following ca. 14,385 cal yr BP, the lake oscillated between moderate to moderately-high levels through the Bolling-Allerod interstadials and into the Younger Dryas stadial. The basin's first occupants arrived along its shore around this time, while the lake still filled the valley floor. These earliest people carried either Western Stemmed or Clovis projectile points, both of which are found along the lake margin. The lake receded into the valley floor ca. 10,300 cal yr BP and dune development began, ringing wetlands and small lakes that persisted in the footprint of the once large lake. By the time Mazama tephra fell 7,600 cal yr BP it blanketed pre-existing dunes and marsh peats. Our Lake Warner lake level curve facilitates interdisciplinary testing and refinement of it and similar curves throughout the region while helping us understand the history of lake and the people who lived along its shores.

Seismic Triggers of Lacustrine Subaqueous Landslides in Lake Champlain, USA

NASA Astrophysics Data System (ADS)

Manley, P.; Manley, T.; Ghosh, S. J.; Rosales-Underbrink, P.; Silverhart, P.

2017-12-01

Lacustrine slumps and debris flows (landslides) have been identified in Lake Champlain via Multibeam and CHIRP (compressed high intensity radar pulse) seismic profile data. Numerous large landslides studied by Ghosh (2012), Rosales-Underbrink (2015), and Silverhart (2016) have shown that many of these landslides are coeval. All landslides failed on a specific interface between marine Champlain Sea and modern lacustrine Lake Champlain sediments. Utilizing radionuclide dating on sediment from the unfailed slopes or undisturbed sediment above failed deposits, sedimentation rates were determined and used to calculate the approximate failure ages for each of the landslides studied. The northernmost failure, south of the Bouquet River, occurred about 950-1200 cal yr BP and is the first mass wasting event of this age to be recorded on Lake Champlain. The remaining landslides failed about 4500-5200 cal yr BP and agree with nearby Western Quebec Seismic Zone (WQSZ) with clusters of terrestrial landslides occurring at 1000 and 5000 cal yr BP triggered by large earthquakes (Brooks, 2015) along the same interface. The 5000 cal yr BP event has been attributed to a M 6.4 or greater earthquake within the WQSZ. The coeval landslides observed in Lake Champlain were likely triggered by this same earthquake. Lake tsunami models show that these simultaneous landslide failures can generate surface waves wave that can impact the Lake Champlain shoreline within 3-10 minutes after the earthquake.

Dissolved-solids contribution to the Colorado River from public lands in southeastern Nevada, through September 1993

USGS Publications Warehouse

Westenburg, C.L.

1995-01-01

The Bureau of Land Management administers about 9,300 square miles of public lands in southeastern Nevada that are part of the Colorado River Basin. The U.S. Geological Survey, in cooperation with the Bureau of Land Management, began a 5-year program in October 1988 to assess the contribution of dissolved solids to the fiver from those lands. About 6,200 square miles of public lands are in the Muddy River subbasin in Nevada. The estimated average dissolved-solids load contributed to the Colorado River from those lands was 28,000 tons per year from October 1988 through September 1993. Subsurface flow contributed about 86 percent (24,000 tons per year) of that load. About 730 square miles of public lands in the Las Vegas Wash subbasin contribute dissolved-solids load to the Colorado River. (About 120 square miles of public lands do not contribute to the river.) The estimated average dissolved-solids load contributed to the river from those lands was about 1,300 tons per year from October 1988 through September 1993. Subsurface flow contributed almost all of that load. About 1,100 square miles of public lands are in the Virgin River subbasin in Nevada. The estimated average dissolved- solids load contributed to the Colorado River from Nevada public lands in the subbasin was 8,700 tons per year. Subsurface flow contributed almost the entire load. About 1,200 square miles of Nevada public lands are in ephemeral tributaries that drain direcfly to the Colorado River or its impoundments (Lake Mead and Lake Mobave). The estimated average dissolved-solids load contributed to the river from those lands was 50 tons per year from surface runoff; however, the dissolved-solids load contributed by subsurface flow was not estimated. From October 1992 to September 1993, the Colorado River carried about 6,600,000 tons of dissolved solids past a streamflow gaging station 0.3 mile downstream from Hoover Dam. In contrast, surface runoff and subsurface flow contribute an estimated

Potential environmental effects of pack stock on meadow ecosystems of the Sierra Nevada, USA

USGS Publications Warehouse

Ostoja, Steven M.; Brooks, Matthew L.; Moore, Peggy E.; Berlow, Eric L.; Robert Blank,; Roche, Jim; Chase, Jennifer T.; Sylvia Haultain,

2014-01-01

Pack and saddle stock, including, but not limited to domesticated horses, mules, and burros, are used to support commercial, private and administrative activities in the Sierra Nevada. The use of pack stock has become a contentious and litigious issue for land management agencies in the region inter alia due to concerns over effects on the environment. The potential environmental effects of pack stock on Sierra Nevada meadow ecosystems are reviewed and it is concluded that the use of pack stock has the potential to influence the following: (1) water nutrient dynamics, sedimentation, temperature, and microbial pathogen content; (2) soil chemistry, nutrient cycling, soil compaction and hydrology; (3) plant individuals, populations and community dynamics, non-native invasive species, and encroachment of woody species; and (4) wildlife individuals, populations and communities. It is considered from currently available information that management objectives of pack stock should include the following: minimise bare ground, maximise plant cover, maintain species composition of native plants, minimise trampling, especially on wet soils and stream banks, and minimise direct urination and defecation by pack stock into water. However, incomplete documentation of patterns of pack stock use and limited past research limits current understanding of the effects of pack stock, especially their effects on water, soils and wildlife. To improve management of pack stock in this region, research is needed on linking measurable monitoring variables (e.g. plant cover) with environmental relevancy (e.g. soil erosion processes, wildlife habitat use), and identifying specific environmental thresholds of degradation along gradients of pack stock use in Sierra Nevada meadows.

Starshade Test in Nevada

NASA Image and Video Library

2016-08-09

A test of a small-scale starshade model in a dry lake bed in central Nevada's Smith Creek by Northrup Grumman in May-June 2014. A telescope points toward a bright light, which mimics the conditions of starlight in space. Other lights, which are up to 10 million times fainter than the light source standing in for the star, represent the reflected light of planets. Telescopes searching for the relatively dim light of an exoplanet next to its much bright star are faced with a challenge as difficult as searching from Los Angeles for a firefly in New York– if the firefly is also beside a lighthouse. These tests determined that a starshade, or external occulter, is indeed capable of blocking starlight to a degree that reveals the light of a planet. http://photojournal.jpl.nasa.gov/catalog/PIA20908

Insights on Lithospheric Foundering from the Sierra Nevada Earthscope Project (SNEP)

NASA Astrophysics Data System (ADS)

Zandt, G.; Gilbert, H.; Frassetto, A.; Owens, T.; Jones, C.

2004-12-01

Interdisciplinary studies in the southern Sierra Nevada have documented an ongoing removal of the dense residual root from beneath the southern Sierra Nevada batholith. However, many questions remain concerning the timing, spatial extent, mechanism, and consequences of this lithospheric foundering event. The Sierra Nevada Earthscope Project (SNEP) is a scientific experiment designed to investigate these questions with a 2- phase (2 year) seismic deployment of 46 broadband Flex-Array stations embedded in the existing stations of the USArray Transportable Array (TA) in the region. In the 2 phases, approximately 80 sites have been occupied from the northern edge of Kings Canyon north to Honey Lake and from the Central Valley into the Great Basin. In this presentation, we will focus on the most recent common-conversion-point (CCP) stacks of the receiver functions that provide a 3D image of lithospheric layering beneath the central and northern Sierra Nevada. Examining sequential cross-sections reveals distinctive lithospheric "reflectivity" patterns that characterize different tectonic imprints. From phase 1 data, we observed that the westernmost Basin and Range exhibits strong layering with multiple low-velocity zones in the crust and uppermost mantle and a relatively flat and strong Moho varying slowly in depth between 30 and 35 km. In the south this Basin and Range character terminates on the eastern edge of the Sierra Nevada; however, north of Big Pine the Basin and Range character intrudes progressively farther into the range and ends up more than 50 km west of the eastern edge of the range. The lithosphere beneath the southern high Sierra Nevada is characterized by a relatively transparent (homogeneous) crust and sharp Moho that disappears westward beneath the adjacent foothills. The crustal thickness in this area is mostly between 30-35 km with localized welts of thicker crust. The phase 1 observations imply that the removal process appears to be actively

Insights on Lithospheric Foundering from the Sierra Nevada Earthscope Project (SNEP)

NASA Astrophysics Data System (ADS)

Zandt, G.; Gilbert, H.; Frassetto, A.; Owens, T.; Jones, C.

2007-12-01

Interdisciplinary studies in the southern Sierra Nevada have documented an ongoing removal of the dense residual root from beneath the southern Sierra Nevada batholith. However, many questions remain concerning the timing, spatial extent, mechanism, and consequences of this lithospheric foundering event. The Sierra Nevada Earthscope Project (SNEP) is a scientific experiment designed to investigate these questions with a 2- phase (2 year) seismic deployment of 46 broadband Flex-Array stations embedded in the existing stations of the USArray Transportable Array (TA) in the region. In the 2 phases, approximately 80 sites have been occupied from the northern edge of Kings Canyon north to Honey Lake and from the Central Valley into the Great Basin. In this presentation, we will focus on the most recent common-conversion-point (CCP) stacks of the receiver functions that provide a 3D image of lithospheric layering beneath the central and northern Sierra Nevada. Examining sequential cross-sections reveals distinctive lithospheric "reflectivity" patterns that characterize different tectonic imprints. From phase 1 data, we observed that the westernmost Basin and Range exhibits strong layering with multiple low-velocity zones in the crust and uppermost mantle and a relatively flat and strong Moho varying slowly in depth between 30 and 35 km. In the south this Basin and Range character terminates on the eastern edge of the Sierra Nevada; however, north of Big Pine the Basin and Range character intrudes progressively farther into the range and ends up more than 50 km west of the eastern edge of the range. The lithosphere beneath the southern high Sierra Nevada is characterized by a relatively transparent (homogeneous) crust and sharp Moho that disappears westward beneath the adjacent foothills. The crustal thickness in this area is mostly between 30-35 km with localized welts of thicker crust. The phase 1 observations imply that the removal process appears to be actively

Length-weight relationship and a relative condition factor equation for lake sturgeon (Acipenser fulvescens) from the St. Clair River system (Michigan, USA)

USGS Publications Warehouse

Craig, Jaquelyn M.; Thomas, Michael V.; Nichols, Susan Jerrine

2005-01-01

Several USA state, federal, and Canadian agencies study lake sturgeon (Acipenser fulvescens) within the St Clair River and Lake St Clair, collectively referred to hereafter as the St Clair River (SCR) system. Previously, there has been no set standard for determining condition for SCR system lake sturgeon. Condition measures the variation from the expected weight for length as an indicator of fatness, general well-being, gonad development, etc. The aim of this project was to determine the length–weight relationship of lake sturgeon caught from the SCR system, from which a relative condition factor (Kn) equation could be derived. Total length (TL, mm) and weight (W, kg) were measured for 1074 lake sturgeon (101 males and 16 females were identifiable) collected by setline and bottom trawl from the SCR system in May–September, 1997–2002. Analysis of covariance found no difference in the length–weight relationship between sampling gear or sex. Least-squares regression of log10W × log10TL produced the overall equation logW = 3.365logTL − 9.320. Using the exponential form of the slope and y-intercept, relative condition factor for lake sturgeon from the SCR system can be calculated as Kn = W/[(4.786 × 10−10)(TL3.365)]. Equations for males and females were also developed. Overall, body condition was significantly correlated with both age and girth; no significant difference in Kn by sex was found. In general, the SCR lake sturgeon population was near the upper ends of growth and condition ranges listed in the literature, comparable with those populations that are at similar latitudes. Although condition factors should be interpreted with caution, proper use of a standard equation provides a non-lethal measure of overall fish health that can be used by biologists and managers in ongoing efforts to restore lake sturgeon throughout the Great Lakes.

NASA Images Show Decreased Clarity in Lake Tahoe Water

NASA Image and Video Library

2002-08-06

Images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer aboard NASA's Terra satellite, launched in 1999, illustrate the state of gradually decreasing water clarity at Lake Tahoe, one of the clearest lakes in the world. The images are available at: http://asterweb.jpl.nasa.gov/default.htm. In the image on the left, acquired in November 2000, vegetation can be seen in red. The image on the right, acquired at the same time by a different spectral band of the instrument, is color-coded to show the bottom of the lake around the shoreline. Where the data are black, the bottom cannot be seen. Scientists monitoring the lake's water clarity from boat measurements obtained since 1965 have discovered that the lake along the California-Nevada border has lost more than one foot of visibility each year, according to the Lake Tahoe Watershed Assessment, a review of scientific information about the lake undertaken at the request of President Clinton and published in February 2000. The most likely causes are increases in algal growth, sediment washed in from surrounding areas and urban growth and development. http://photojournal.jpl.nasa.gov/catalog/PIA03854

Mid Holocene lake level and shoreline behavior during the Nipissing phase of the upper Great Lakes at Alpena, Michigan, USA

USGS Publications Warehouse

Thompson, T.A.; Lepper, K.; Endres, A.L.; Johnston, J.W.; Baedke, S.J.; Argyilan, E.P.; Booth, R.K.; Wilcox, D.A.

2011-01-01

The Nipissing phase was the last pre-modern high-water stage of the upper Great Lakes. Represented as either a one- or two-peak highstand, the Nipissing occurred following a long-term lake-level rise. This transgression was primarily an erosional event with only the final stage of the transgression preserved as barriers, spits, and strandplains of beach ridges. South of Alpena, Michigan, mid to late Holocene coastal deposits occur as a strandplain between Devils Lake and Lake Huron. The landward part of this strandplain is a higher elevation platform that formed during the final stage of lake-level rise to the Nipissing peak. The pre-Nipissing shoreline transgressed over Devils Lake lagoonal deposits from 6.4 to 6.1. ka. The first beach ridge formed ~ 6. ka, and then the shoreline advanced toward Lake Huron, producing beach ridges about every 70. years. This depositional regression produced a slightly thickening wedge of sediment during a lake-level rise that formed 20 beach ridges. The rise ended at 4.5. ka at the Nipissing peak. This peak was short-lived, as lake level fell > 4. m during the following 500. years. During this lake-level rise and subsequent fall, the shoreline underwent several forms of shoreline behavior, including erosional transgression, aggradation, depositional transgression, depositional regression, and forced regression. Other upper Great Lakes Nipissing platforms indicate that the lake-level change observed at Alpena of a rapid pre-Nipissing lake-level rise followed by a slower rise to the Nipissing peak, and a post-Nipissing rapid lake-level fall is representative of mid Holocene lake level in the upper Great Lakes. ?? 2011 Elsevier B.V.

High Elevation Lakes of the Western US: Are we Studying Systems Recovering from Excess Atmospheric Deposition of Acids and Nutrients?

NASA Astrophysics Data System (ADS)

Sickman, J. O.

2011-12-01

Instrumental records and monitoring of high elevation lakes began in most areas of the western US in the early 1980s. Much effort has been devoted to detecting changes in these aquatic ecosystems resulting from increased atmospheric deposition of acids and nutrients. However, there is growing evidence that thresholds for atmospheric pollutants were crossed much earlier in the 20th Century and that some of the subsequent hydrochemical and ecological changes observed in these lakes may be the result of recovery from earlier atmospheric forcing. We examine responses of high elevation lakes to atmospheric deposition on annual to century timescales using data from a 29-year study of Emerald Lake (Sequoia National Park) and paleolimnological analyses of other high elevation lakes incorporating diatom species analyses and geochemical proxies for fossil-fuel burning. At Emerald Lake, we have observed multiple transitions between nitrogen and phosphorus limitation of phytoplankton, the earliest of which occurred in the beginning of the 1980s and may be the result of reduction in N deposition due to the Clean Air Act. Critical loads analyses incorporating diatom species in lake sediments suggest that thresholds for N deposition were crossed in the period of 1950-1980 in the Rocky Mountains and likely much earlier, 1900-1920, in the Sierra Nevada. Diatom species composition is strongly controlled by acid neutralizing capacity (ANC) in the Sierra Nevada and we have observed a pronounced decline and recovery of ANC over the period of 1920-1980 in some Sierra Nevada lakes that coincides with the abundance of spheroidal carbonaceous particles (i.e., a diagnostic tracer of fossil fuel combustion) preserved in lake sediments; these patterns appear to be driven by increased emissions of oxidized N and S in the mid-20th Century and reductions in acid precursor levels caused by the Clean Air Act in the 1970s. Thus, when interpreting observational records from western high elevation

Recognition of Macluritella ( Gastropoda) from the Upper Cambrian of Missouri and Nevada ( USA).

USGS Publications Warehouse

Yochelson, E.L.; Stinchcomb, B.L.

1987-01-01

Open-coiled euomphalacean gastropods have been identified for the first time in the Upper Cambrian Eminence Dolomite of Missouri. These gastropods have a triangular whorl profile and are conspecific with Hyolithes walcotti described from the Upper Cambrian of Nevada. That species is questionably reassigned to the gastropod genus Macluritella, hitherto known only from the Lower Ordovician of Colorado. -Authors Ordovician Colorado

Tale of two pit lakes: initial results of a three-year study of the Main Zone and Waterline pit lakes near Houston, British Columbia, Canada

USGS Publications Warehouse

Crusius, John; Pieters, R.; Leung, A.; Whittle, P.; Pedersen, T.; Lawrence, G.; McNee, J.J.

2003-01-01

Pit lakes are becoming increasingly common in North America as well as in the rest of the world. They are created as openpit mines fill passively with ground water and surface inflows on cessation of mining activity. In many instances, the water quality in these pit lakes does not meet regulatory requirements due to a number of influences. The most important are the oxidation of sulfide minerals and the associated release of acid and metals and the flushing of soluble metals during pit filling. Examples of pit lakes with severe water-quality problems include the Berkeley Pit lake (Butte, MT) and the Liberty Pit lake (Nevada), whose waters are characterized by a pH near 3 and Cu concentrations as high as ~150 mg/L (Miller et al., 1996; Davis and Eary, 1997). The importance of the problem can be seen in the fact that some of these sites in the United States are Superfund sites.

Multi-scale evaluation of the environmental controls on burn probability in a southern Sierra Nevada landscape

Treesearch

Sean A. Parks; Marc-Andre Parisien; Carol Miller

2011-01-01

We examined the scale-dependent relationship between spatial fire likelihood or burn probability (BP) and some key environmental controls in the southern Sierra Nevada, California, USA. Continuous BP estimates were generated using a fire simulation model. The correspondence between BP (dependent variable) and elevation, ignition density, fuels and aspect was evaluated...

Suppression of invasive lake trout in an isolated backcountry lake in Glacier National Park

USGS Publications Warehouse

Fredenberg, C. R.; Muhlfeld, Clint C.; Guy, Christopher S.; D'Angelo, Vincent S.; Downs, Christopher C.; Syslo, John M.

2017-01-01

Fisheries managers have implemented suppression programmes to control non-native lake trout, Salvelinus namaycush (Walbaum), in several lakes throughout the western United States. This study determined the feasibility of experimentally suppressing lake trout using gillnets in an isolated backcountry lake in Glacier National Park, Montana, USA, for the conservation of threatened bull trout, Salvelinus confluentus (Suckley). The demographics of the lake trout population during suppression (2009–2013) were described, and those data were used to assess the effects of suppression scenarios on population growth rate (λ) using an age-structured population model. Model simulations indicated that the population was growing exponentially (λ = 1.23, 95% CI: 1.16–1.28) prior to suppression. However, suppression resulted in declining λ(0.61–0.79) for lake trout, which was concomitant with stable bull trout adult abundances. Continued suppression at or above observed exploitation levels is needed to ensure continued population declines.

Sedimentary constraints on late Quaternary lake-level fluctuations at Bear Lake, Utah and Idaho

USGS Publications Warehouse

Smoot, J.P.; Rosenbaum, J.G.

2009-01-01

is more similar to records from Pyramid Lake, Nevada, and Owens Lake, California, than to those from Lake Bonneville, Utah. Copyright ?? 2009 The Geological Society of America.

Release of elements to natural water from sediments of Lake Roosevelt, Washington, USA

USGS Publications Warehouse

Paulson, Anthony J.; Cox, Stephen E.

2007-01-01

Reservoir sediments from Lake Roosevelt (WA, USA) that were contaminated with smelter waste discharged into the Columbia River (BC, Canada) were examined using three measures of elemental release reflecting varying degrees of physical mixing and time scales. Aqueous concentrations of Cd, Cu, Pb, and Zn in the interstitial water of reservoir sediments, in the gently stirred overlying waters of incubated sediment cores, and in supernatants of aggressively tumbled slurries of reservoir sediments generally were higher than the concentrations from a reference site. When compared to chronic water-quality criteria, all three measures of release suggest that slag-contaminated sediments near the U.S.-Canadian border are potentially toxic as a result of Cu release and Pb release in two of the three measures. All three measures of Cd release suggest potential toxicity for one site farther down the reservoir, probably contaminated as a result of transport and adsorption of Cd from smelter liquid waste. Releases of Zn and As did not appear to be potentially toxic. Carbonate geochemistry indirectly affects the potential toxicity by increasing water hardness.

Lake trout (Salvelinus namaycush) suppression for bull trout (Salvelinus confluentus) recovery in Flathead Lake, Montana, North America

USGS Publications Warehouse

Hansen, Michael J.; Hansen, Barry S; Beauchamp, David A.

2016-01-01

Non-native lake trout Salvelinus namaycush displaced native bull trout Salvelinus confluentus in Flathead Lake, Montana, USA, after 1984, when Mysis diluviana became abundant following its introduction in upstream lakes in 1968–1976. We developed a simulation model to determine the fishing mortality rate on lake trout that would enable bull trout recovery. Model simulations indicated that suppression of adult lake trout by 75% from current abundance would reduce predation on bull trout by 90%. Current removals of lake trout through incentivized fishing contests has not been sufficient to suppress lake trout abundance estimated by mark-recapture or indexed by stratified-random gill netting. In contrast, size structure, body condition, mortality, and maturity are changing consistent with a density-dependent reduction in lake trout abundance. Population modeling indicated total fishing effort would need to increase 3-fold to reduce adult lake trout population density by 75%. We conclude that increased fishing effort would suppress lake trout population density and predation on juvenile bull trout, and thereby enable higher abundance of adult bull trout in Flathead Lake and its tributaries.

Combined use of frequency-domain electromagnetic and electrical resistivity surveys to delineate near-lake groundwater flow in the semi-arid Nebraska Sand Hills, USA

USGS Publications Warehouse

Ong, John B.; Lane, John W.; Zlotnik, Vitaly A.; Halihan, Todd; White, Eric A.

2010-01-01

A frequency-domain electromagnetic (FDEM) survey can be used to select locations for the more quantitative and labor-intensive electrical resistivity surveys. The FDEM survey rapidly characterized the groundwater-flow directions and configured the saline plumes caused by evaporation from several groundwater-dominated lakes in the Nebraska Sand Hills, USA. The FDEM instrument was mounted on a fiberglass cart and towed by an all-terrain vehicle, covering about 25 km/day. Around the saline lakes, areas with high electrical conductivity are consistent with the regional and local groundwater flow directions. The efficacy of this geophysical approach is attributed to: the high contrast in electrical conductivity between various groundwater zones; the shallow location of the saline zones; minimal cultural interference; and relative homogeneity of the aquifer materials.

Water-related scientific activities of the U.S. Geological Survey in Nevada, fiscal years 1985-89

USGS Publications Warehouse

Kilroy, Kathryn C.

1989-01-01

The U.S. Geological Survey has been collecting water resources data in Nevada since 1890. Most of the projects in the current Nevada District program can be classified as either basic-data acquisition (about 25%) or hydrologic interpretation (about 75 %). About 52% of the activities are supported by cooperative agreements with State and local agencies. Technical projects supported by other Federal agencies make up about 23% of the program, and the remaining 25% consists of data collection, research, and interpretive projects supported directly by the U.S. Geological Survey. Water conditions in Nevada during the 4 years covered by this report were by no means average, with 1 very wet year (1986) and 2 very dry years (1987-88). The major water resources issues include: water allocation in the Truckee-Carson River basin; irrigation return flow contamination of the Stillwater Wildlife Management Area; effects of weapons testing at the Nevada Test Site; assessment of potential long-term impacts of the proposed Yucca Mountain Nuclear Waste Repository; and drought. Future water-resources issues in Nevada are likely to center on water supply for and the environmental effects of, the rapidly growing population centers at Las Vegas, Reno, and Elko; impacts of operations at the Nevada Test Site; management of interstate rivers such as the Truckee and Colorado Rivers; hydrologic and environmental impacts at heavily mined areas; and water quality management in the Lake Tahoe Basin. (Thacker-USGS-WRD)

Massive infestation by Amyloodinium ocellatum (Dinoflagellida) of fish in a highly saline lake, Salton Sea, California, USA.

PubMed

Kuperman, B I; Matey, V E

1999-12-22

Persistent fish infestation by the parasitic dinoflagellate Amyloodinium ocellatum was found at a highly saline lake, Salton Sea, California, USA. The seasonal dynamics of the infestation of young tilapia was traced in 1997-1998. First appearing in May, it became maximal in June-August, decreased in October and was not detectable in November. Outbreak of the infestation and subsequent mortality of young fish was registered at the Sea at a water temperature and salinity of 40 degrees C and 46 ppt, respectively. Some aspects of the ultrastructure of parasitic trophonts of A. ocellatum and their location on the fish from different size groups are considered. The interactions of parasitological and environmental factors and their combined effect upon fish from the Salton Sea are discussed.

THE CHALLENGE OF ACQUIRING ALPINE LARGE VOLUME LAKE WATER SAMPLES FOR ULTRA TRACE LEVEL ANALYSIS

EPA Science Inventory

The National Exposure Research Laboratory-Las Vegas, Nevada is interested in the emerging field technology of in-situ extraction of contaminants from surface water. A current research project involves ultra-trace level determination of agricultural pesticides from alpine lakes. T...

Temporal coherence of two alpine lake basins of the Colorado Front Range, USA

USGS Publications Warehouse

Baron, Jill S.; Caine, N.

2000-01-01

1. Knowledge of synchrony in trends is important to determining regional responses of lakes to disturbances such as atmospheric deposition and climate change. We explored the temporal coherence of physical and chemical characteristics of two series of mostly alpine lakes in nearby basins of the Colorado Rocky Mountains. Using year-to-year variation over a 10-year period, we asked whether lakes more similar in exposure to the atmosphere be-haved more similarly than those with greater influence of catchment or in-lake processes.2. The Green Lakes Valley and Loch Vale Watershed are steeply incised basins with strong altitudinal gradients. There are glaciers at the heads of each catchment. The eight lakes studied are small, shallow and typically ice-covered for more than half the year. Snowmelt is the dominant hydrological event each year, flushing about 70% of the annual discharge from each lake between April and mid-July. The lakes do not thermally stratify during the period of open water. Data from these lakes included surface water temper-ature, sulphate, nitrate, calcium, silica, bicarbonate alkalinity and conductivity.3. Coherence was estimated by Pearson's correlation coefficient between lake pairs for each of the different variables. Despite close geographical proximity, there was not a strong direct signal from climatic or atmospheric conditions across all lakes in the study. Individual lake characteristics overwhelmed regional responses. Temporal coherence was higher for lakes within each basin than between basins and was highest for nearest neighbours.4. Among the Green Lakes, conductivity, alkalinity and temperature were temporally coherent, suggesting that these lakes were sensitive to climate fluctuations. Water tem-perature is indicative of air temperature, and conductivity and alkalinity concentrations are indicative of dilution from the amount of precipitation flushed through by snowmelt.5. In Loch Vale, calcium, conductivity, nitrate, sulphate and

Crustal Rebound due to Lake Mass Changes Measured by InSAR: Constraints on Lithosphere Rheology

NASA Astrophysics Data System (ADS)

Doin, M. P.; Twardzik, C.; Cavalié, O.; Lasserre, C.

2015-12-01

SAR interferometry has proven to be a reliable method for detecting small displacements due to ground subsidence. Here, we relate ground motion around the lake Mead (Nevada, USA) and lake Siling Co (Tibet, China) measured by InSAR to water loading in order to constrain the rheology of the lithosphere.Lake Mead, an artificial reservoir, has been filled with water in 1935. We analyzed ~500 interferograms based on 62 ERS images and on 40 ENVISAT images acquired between 1992 and 2010. Interferograms are inverted to solve for the time series of ground motion in the lake Mead area. Temporal smoothing allows to reduce the turbulent atmospheric delays. Spatio-temporal series of the deformation from 1992 to 2010 show a broad subsidence pattern correlated with lake level from 1992 to 2010. We model the deformation, taking into account the water and sediment loading history of the lake since 1935. The two-layer visco-elastic model proposed by Kaufmann and Amelung (2000), with a mantle viscosity of 1018 Pa s, adjusts well the data up to 2001, but overpredicts the deformation after 2001. We will discuss the models that could explain the deformation evolution. The Siling Co lake is the largest endorheic lake in Central Tibet. In 1972-1999 its water level remained stable, while it increased by about 1.0~m/yr in the period 2000-2006. The increased rate gradually stepped down to 0.2~m/yr in 2007-2011. We analysed 107 ERS and Envisat SAR images during the period 1992-2011. The deformation amplitude closely follows the lake level temporal evolution, except that subsidence continues in 2008-2011, while the lake level stagnated. This temporal evolution suggests a non elastic relaxation process taking place at a decade time-scale. Phase delay maps are used to constrain possible layered visco-elastic rheological models. An elastic model could partly explain the observed subsidence rate if elastic moduli are about twice lower than those extracted from Vp/Vs profiles. The surface

The dynamic response of Kennicott Glacier, Alaska, USA, to the Hidden Creek Lake outburst flood

USGS Publications Warehouse

Anderson, R. Scott; Walder, J.S.; Anderson, S.P.; Trabant, D.C.; Fountain, A.G.

2005-01-01

Glacier sliding is commonly linked with elevated water pressure at the glacier bed. Ice surface motion during a 3 week period encompassing an outburst of ice-dammed Hidden Creek Lake (HCL) at Kennicott Glacier, Alaska, USA, showed enhanced sliding during the flood. Two stakes, 1.2 km from HCL, revealed increased speed in two episodes, both associated with uplift of the ice surface relative to the trajectory of bed-parallel motion. Uplift of the surface began 12 days before the flood, initially stabilizing at a value of 0.25 m. Two days after lake drainage began, further uplift (reaching 0.4 m) occurred while surface speed peaked at 1.2 m d-1. Maximum surface uplift coincided with peak discharge from HCL, high water level in a down-glacier ice-marginal basin, and low solute concentrations in the Kennicott River. Each of these records is consistent with high subglacial water pressure. We interpret the ice surface motion as arising from sliding up backs of bumps on the bed, which enlarges cavities and produces bed separation. The outburst increased water pressure over a broad region, promoting sliding, inhibiting cavity closure, and blocking drainage of solute-rich water from the distributed system. Pressure drop upon termination of the outburst drained water from and depressurized the distributed system, reducing sliding speeds. Expanded cavities then collapsed with a 1 day time-scale set by the local ice thickness.

A food web modeling analysis of a Midwestern, USA eutrophic lake dominated by non-native Common Carp and Zebra Mussels

USGS Publications Warehouse

Colvin, Michael E.; Pierce, Clay; Stewart, Timothy W.

2015-01-01

Food web modeling is recognized as fundamental to understanding the complexities of aquatic systems. Ecopath is the most common mass-balance model used to represent food webs and quantify trophic interactions among groups. We constructed annual Ecopath models for four consecutive years during the first half-decade of a zebra mussel invasion in shallow, eutrophic Clear Lake, Iowa, USA, to evaluate changes in relative biomass and total system consumption among food web groups, evaluate food web impacts of non-native common carp and zebra mussels on food web groups, and to interpret food web impacts in light of on-going lake restoration. Total living biomass increased each year of the study; the majority of the increase due to a doubling in planktonic blue green algae, but several other taxa also increased including a more than two-order of magnitude increase in zebra mussels. Common carp accounted for the largest percentage of total fish biomass throughout the study even with on-going harvest. Chironomids, common carp, and zebra mussels were the top-three ranking consumer groups. Non-native common carp and zebra mussels accounted for an average of 42% of the total system consumption. Despite the relatively high biomass densities of common carp and zebra mussel, food web impacts was minimal due to excessive benthic and primary production in this eutrophic system. Consumption occurring via benthic pathways dominated system consumption in Clear Lake throughout our study, supporting the argument that benthic food webs are significant in shallow, eutrophic lake ecosystems and must be considered if ecosystem-level understanding is to be obtained.

Microbial Community Structure and Biogeochemistry of Three Small Eutrophic Lakes

EPA Science Inventory

Background: The three Jackson Lakes within the Bayou Chico Watershed in NW FL, USA were formed at different times from abandoned sand pits. The lakes experienced inundation with marine water during Hurricane Ivan 2004 and, despite their proximity and similar physical structures, ...

Complex postglacial recolonization inferred from population genetic structure of mottled sculpin Cottus bairdii in tributaries of eastern Lake Michigan, U.S.A.

PubMed

Homola, J J; Ruetz, C R; Kohler, S L; Thum, R A

2016-11-01

This study used analyses of the genetic structure of a non-game fish species, the mottled sculpin Cottus bairdii to hypothesize probable recolonization routes used by cottids and possibly other Laurentian Great Lakes fishes following glacial recession. Based on samples from 16 small streams in five major Lake Michigan, U.S.A., tributary basins, significant interpopulation differentiation was documented (overall F ST = 0·235). Differentiation was complex, however, with unexpectedly high genetic similarity among basins as well as occasionally strong differentiation within basins, despite relatively close geographic proximity of populations. Genetic dissimilarities were identified between eastern and western populations within river basins, with similarities existing between eastern and western populations across basins. Given such patterns, recolonization is hypothesized to have occurred on three occasions from more than one glacial refugium, with a secondary vicariant event resulting from reduction in the water level of ancestral Lake Michigan. By studying the phylogeography of a small, non-game fish species, this study provides insight into recolonization dynamics of the region that could be difficult to infer from game species that are often broadly dispersed by humans. © 2016 The Fisheries Society of the British Isles.

Predicted effects of future climate warming on thermal habitat suitability for Lake Sturgeon (Acipenser fulvescens, Rafinesque, 1817) in rivers in Wisconsin, USA

USGS Publications Warehouse

Lyons, John D.; Stewart, Jana S.

2015-01-01

The Lake Sturgeon (Acipenser fulvescens, Rafinesque, 1817) may be threatened by future climate warming. The purpose of this study was to identify river reaches in Wisconsin, USA, where they might be vulnerable to warming water temperatures. In Wisconsin, A. fulvescens is known from 2291 km of large-river habitat that has been fragmented into 48 discrete river-lake networks isolated by impassable dams. Although the exact temperature tolerances are uncertain, water temperatures above 28–30°C are potentially less suitable for this coolwater species. Predictions from 13 downscaled global climate models were input to a lotic water temperature model to estimate amounts of potential thermally less-suitable habitat at present and for 2046–2065. Currently, 341 km (14.9%) of the known habitat are estimated to regularly exceed 28°C for an entire day, but only 6 km (0.3%) to exceed 30°C. In 2046–2065, 685–2164 km (29.9–94.5%) are projected to exceed 28°C and 33–1056 km (1.4–46.1%) to exceed 30°C. Most river-lake networks have cooler segments, large tributaries, or lakes that might provide temporary escape from potentially less suitable temperatures, but 12 short networks in the Lower Fox and Middle Wisconsin rivers totaling 93.6 km are projected to have no potential thermal refugia. One possible adaptation to climate change could be to provide fish passage or translocation so that riverine Lake Sturgeon might have access to more thermally suitable habitats.

Micronuclei and other erythrocyte nuclear abnormalities in fishes from the Great Lakes Basin, USA.

PubMed

Braham, Ryan P; Blazer, Vicki S; Shaw, Cassidy H; Mazik, Patricia M

2017-10-01

Biological markers (biomarkers) sensitive to genotoxic and mutagenic contamination in fishes are widely used to identify exposure effects in aquatic environments. The micronucleus assay was incorporated into a suite of indicators to assess exposure to genotoxic and mutagenic contamination at five Great Lakes Areas of Concern (AOCs), as well as one non-AOC (reference) site. The assay allowed enumeration of micronuclei as well as other nuclear abnormalities for both site and species comparisons. Erythrocyte abnormality data was also compared to skin and liver tumor prevalence and hepatic transcript abundance. Erythrocyte abnormalities were observed at all sites with variable occurrence and severity among sites and species. Benthic-oriented brown bullhead (Ameiurus nebulosus) and white sucker (Catostomus commersonii) expressed lower rates of erythrocyte abnormalities, but higher rates of skin and liver neoplasms, when compared to pelagic-oriented largemouth bass (Micropterus salmoides) or smallmouth bass (Micropterus dolomieu) at the same site. The reduced erythrocyte abnormalities, increased transcript abundance associated with Phase I and II toxicant responsive pathways, and increased neoplastic lesions among benthic-oriented taxa may indicate the development of contaminant resistance of these species to more acute effects. Environ. Mol. Mutagen. 58:570-581, 2017. © 2017 This article is a U.S. Government work and is in the public domain in the USA. Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society. © 2017 This article is a U.S. Government work and is in the public domain in the USA. Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.

The role of volatile-saturation and adiabatic ascent of moderately hydrous melts on the formation of orbicules and comb layers in shallow subvolcanic conduits (Fisher Lake, Sierra Nevada).

NASA Astrophysics Data System (ADS)

McCarthy, A. J.; Müntener, O.

2016-12-01

Orbicules and comb layers are enigmatic features found sparsely distributed along plutonic contacts in a wide range of igneous environments. We provide new insights into the mechanisms responsible for the formation of these features by studying the spatial distribution, mineralogy and geochemistry of comb layers and orbicules from the Northern Sierra Nevada, Fisher Lake (USA). Over a range of studied comb textured layering, we show that the large majority of comb layers are cumulates formed by the initiation of plagioclase growth as a comb textured mineral. Plagioclase fractionation is followed by pyroxenes + oxides fractionation. Continuous crystal fractionation and conductive cooling from the host rock leads to amphibole saturation and the formation of late stage comb textured amphibole, leading to the formation of plagioclase- and plagioclase-amphibole comb textures. The lack of amphibole comb textures on orbicule rims as opposed to their widespread occurrence in comb layers, suggests that the presence of a thermal gradient plays an important role in diversifying comb textures. We propose that comb layers and orbicules are unique features which are controlled by the volatile content of ascending melts and ascent mechanisms. Thermodynamic calculations indicate that near-adiabatic decompression of water-undersaturated melts (ca. 4wt% H2O) through the crust will lead to superheating and dissolution of pre-existing minerals. Upon saturation of volatiles at shallow depth, degassing-induced undercooling of the decompressing melt will trigger heterogeneous nucleation of plagioclase on host rocks and remobilized xenoliths. The rarity of orbicules and comb layers in volcanic and plutonic rocks worldwide suggests that adiabatic decompression of moderately hydrous melts leading to superheating is a rare phenomena, with most arc melts ascending and cooling in small reservoirs throughout the crust, prior to emplacement at shallow depth as crystal-bearing magmas.

Biological and chemical characterization of metal bioavailability in sediments from Lake Roosevelt, Columbia River, Washington, USA

USGS Publications Warehouse

Besser, J.M.; Brumbaugh, W.G.; Ivey, C.D.; Ingersoll, C.G.; Moran, P.W.

2008-01-01

We studied the bioavailability and toxicity of copper, zinc, arsenic, cadmium, and lead in sediments from Lake Roosevelt (LR), a reservoir on the Columbia River in Washington, USA that receives inputs of metals from an upstream smelter facility. We characterized chronic sediment toxicity, metal bioaccumulation, and metal concentrations in sediment and pore water from eight study sites: one site upstream in the Columbia River, six sites in the reservoir, and a reference site in an uncontaminated tributary. Total recoverable metal concentrations in LR sediments generally decreased from upstream to downstream in the study area, but sediments from two sites in the reservoir had metal concentrations much lower than adjacent reservoir sites and similar to the reference site, apparently due to erosion of uncontaminated bank soils. Concentrations of acid-volatile sulfide in LR sediments were too low to provide strong controls on metal bioavailability, and selective sediment extractions indicated that metals in most LR sediments were primarily associated with iron and manganese oxides. Oligochaetes (Lumbriculus variegatus) accumulated greatest concentrations of copper from the river sediment, and greatest concentrations of arsenic, cadmium, and lead from reservoir sediments. Chronic toxic effects on amphipods (Hyalella azteca; reduced survival) and midge larvae (Chironomus dilutus; reduced growth) in whole-sediment exposures were generally consistent with predictions of metal toxicity based on empirical and equilibrium partitioning-based sediment quality guidelines. Elevated metal concentrations in pore waters of some LR sediments suggested that metals released from iron and manganese oxides under anoxic conditions contributed to metal bioaccumulation and toxicity. Results of both chemical and biological assays indicate that metals in sediments from both riverine and reservoir habitats of Lake Roosevelt are available to benthic invertebrates. These findings will be used as

Sierra Nevada, California as seen from STS-59

NASA Image and Video Library

1994-04-14

STS059-L09-162 (9-20 April 1994) --- Orient with the snow-covered mountains (Sierra Nevada of California) in the upper right corner. Then Owens Valley runs along the top of the photograph to Owens Lake playa at top center. The upper end of Death Valley extends from right to left in the foreground, with the drainage running down to a playa at Stovepipe Wells in the left foreground. Geologists are studying microwave signatures of the different playa surfaces, and the coatings on alluvial fans that extend from mountain masses, to try to sort out the history of different climates in this formerly wet but now hyperarid region.

Spatiotemporal patterns of fault slip rates across the Central Sierra Nevada frontal fault zone

NASA Astrophysics Data System (ADS)

Rood, Dylan H.; Burbank, Douglas W.; Finkel, Robert C.

2011-01-01

, extension is accommodated within a diffuse zone of normal and oblique faults, with extension rates increasing northward on the Fish Lake Valley fault. Where faults of the Eastern California Shear Zone terminate northward into the Mina Deflection, extension rates increase northward along the Sierra Nevada frontal fault zone to ~ 0.7 mm year - 1 in northern Mono Basin. This spatial pattern suggests that extension is transferred from more easterly fault systems, e.g., Fish Lake Valley fault, and localized on the Sierra Nevada frontal fault zone as the Eastern California Shear Zone-Walker Lane belt faulting is transferred through the Mina Deflection.

Spatiotemporal Patterns of Fault Slip Rates Across the Central Sierra Nevada Frontal Fault Zone

NASA Astrophysics Data System (ADS)

Rood, D. H.; Burbank, D.; Finkel, R. C.

2010-12-01

normal and oblique faults, with extension rates increasing northward on the Fish Lake Valley fault. Where faults of the Eastern California Shear Zone terminate northward into the Mina Deflection, extension rates increase northward along the Sierra Nevada frontal fault zone to ~0.7 mm/yr in northern Mono Basin. This spatial pattern suggests that extension is transferred from faults systems to the east (e.g. Fish Lake Valley fault) and localized on the Sierra Nevada frontal fault zone as Eastern California Shear Zone-Walker Lane belt faulting is transferred through the Mina Deflection.

Dust emission at Franklin Lake Playa, Mojave Desert (USA): Response to meteorological and hydrologic changes 2005-2008

USGS Publications Warehouse

Reynolds, Richard L.; Bogle, Rian; Vogel, John; Goldstein, Harland L.; Yount, James

2009-01-01

Playa type, size, and setting; playa hydrology; and surface-sediment characteristics are important controls on the type and amount of atmospheric dust emitted from playas. Soft, evaporite-rich sediment develops on the surfaces of some Mojave Desert (USA) playas (wet playas), where the water table is shallow (< 4 m). These areas are sources of atmospheric dust because of continuous or episodic replenishment of wind-erodible salts and disruption of the ground surface during salt formation by evaporation of ground water. Dust emission at Franklin Lake playa was monitored between March 2005 and April 2008. The dust record, based on day-time remote digital camera images captured during high wind, and compared with a nearby precipitation record, shows that aridity suppresses dust emission. High frequency of dust generation appears to be associated with relatively wet periods, identified as either heavy precipitation events or sustained regional precipitation over a few months. Several factors may act separately or in combination to account for this relation. Dust emission may respond rapidly to heavy precipitation when the dissolution of hard, wind-resistant evaporite mineral crusts is followed by the development of soft surfaces with thin, newly formed crusts that are vulnerable to wind erosion and (or) the production of loose aggregates of evaporite minerals that are quickly removed by even moderate winds. Dust loading may also increase when relatively high regional precipitation leads to decreasing depth to the water table, thereby increasing rates of vapor discharge, development of evaporite minerals, and temporary softening of playa surfaces. The seasonality of wind strength was not a major factor in dust-storm frequency at the playa. The lack of major dust emissions related to flood-derived sediment at Franklin Lake playa contrasts with some dry-lake systems elsewhere that may produce large amounts of dust from flood sediments. Flood sediments do not commonly

Radionuclides in bats using a contaminated pond on the Nevada National Security Site, USA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warren, Ronald W.; Hall, Derek B.; Greger, Paul D.

In this study, perched groundwater percolating through radionuclide contamination in the E Tunnel Complex on the Nevada National Security Site, formerly the Nevada Test Site, emerges and is stored in a series of ponds making it available to wildlife, including bats. Since many bat species using the ponds are considered sensitive or protected/regulated and little information is available on dose to bats from radioactive water sources, bats were sampled to determine if the dose they were receiving exceeded the United States Department of Energy dose limit of 1.0E-3 Gy/day. Radionuclide concentrations in water, sediment, and flying insects were also measuredmore » as input parameters to the dose rate model and to examine trophic level relationships. The RESRAD-Biota model was used to calculate dose rates to bats using different screening levels. Efficacy of RESRAD-Biota and suggested improvements are discussed. Finally, dose to bats foraging and drinking at these ponds is well below the dose limit set to protect terrestrial biota populations.« less

Radionuclides in bats using a contaminated pond on the Nevada National Security Site, USA

DOE PAGES

Warren, Ronald W.; Hall, Derek B.; Greger, Paul D.

2014-01-03

In this study, perched groundwater percolating through radionuclide contamination in the E Tunnel Complex on the Nevada National Security Site, formerly the Nevada Test Site, emerges and is stored in a series of ponds making it available to wildlife, including bats. Since many bat species using the ponds are considered sensitive or protected/regulated and little information is available on dose to bats from radioactive water sources, bats were sampled to determine if the dose they were receiving exceeded the United States Department of Energy dose limit of 1.0E-3 Gy/day. Radionuclide concentrations in water, sediment, and flying insects were also measuredmore » as input parameters to the dose rate model and to examine trophic level relationships. The RESRAD-Biota model was used to calculate dose rates to bats using different screening levels. Efficacy of RESRAD-Biota and suggested improvements are discussed. Finally, dose to bats foraging and drinking at these ponds is well below the dose limit set to protect terrestrial biota populations.« less

Effects of Landscape Conditions and Management Practices on Lakes in Northeastern USA.

EPA Science Inventory

Lakes continue to face escalating pressures associated with land cover change and growing human populations. The U.S. EPA National Lakes Assessment, which sampled 1,028 lakes during the summer of 2007 using a probabilistic survey, was the first large scale effort to determine the...

Stratigraphic evidence for the role of lake spillover in the inception of the lower Colorado River in southern Nevada and western Arizona

USGS Publications Warehouse

House, P.K.; Pearthree, P.A.; Perkins, M.E.

2008-01-01

Late Miocene and early Pliocene sediments exposed along the lower Colorado River near Laughlin, Nevada, contain evidence that establishment of this reach of the river after 5.6 Ma involved flooding from lake spillover through a bedrock divide between Cottonwood Valley to the north and Mohave Valley to the south. Lacustrine marls interfingered with and conformably overlying a sequence of post-5.6 Ma finegrained valley-fill deposits record an early phase of intermittent lacustrine inundation restricted to Cottonwood Valley. Limestone, mud, sand, and minor gravel of the Bouse Formation were subsequently deposited above an unconformity. At the north end of Mohave Valley, a coarse-grained, lithologically distinct fluvial conglomerate separates subaerial, locally derived fan deposits from subaqueous deposits of the Bouse Formation. We interpret this key unit as evidence for overtopping and catastrophic breaching of the paleodivide immediately before deep lacustrine inundation of both valleys. Exposures in both valleys reveal a substantial erosional unconformity that records drainage of the lake and predates the arrival of sediment of the through-going Colorado River. Subsequent river aggradation culminated in the Pliocene between 4.1 and 3.3 Ma. The stratigraphic associations and timing of this drainage transition are consistent with geochemical evidence linking lacustrine conditions to the early Colorado River, the timings of drainage integration and canyon incision on the Colorado Plateau, the arrival of Colorado River sand at its terminus in the Salton Trough, and a downstream-directed mode of river integration common in areas of crustal extension. ?? 2008 The Geological Society of America.

Status of the Sierra Nevada: the Sierra Nevada Ecosystem Project

USGS Publications Warehouse

Erman, Don C.; ,

1997-01-01

The Sierra Nevada ecosystem project was requested by Congress in the Conference Report for Interior and related Agencies 1993 Appropriation Act, which authorized funds for a scientific review of the remaining old growth in the national forests of the Sierra Nevada in California, and for a study of the entire Sierra Nevada ecosystem by an independent panel of scientists, with expertise in diverse areas related to this issue. This CD-ROM is a digital version of the set of reports titled 'Sierra Nevada Ecosystem Project, final report to Congress' published in paper form by the Centers for Water and Wildland Resources of the University of California, Davis.

Ground-water quality in Douglas County, western Nevada

USGS Publications Warehouse

Garcia, K.T.

1989-01-01

A 182% increase in population within the last 10 years in Douglas County, Nevada, has raised concerns by county officials as to the possible effects land development may have on groundwater quality. Most groundwater in Douglas County meets the State of Nevada drinking water standards. Of the 333 water samples used in this analysis, 6 equaled or were greater than the drinking water standards for sulfates, 44 for fluoride, 4 for dissolved solids, 5 for nitrate as nitrate, 12 for arsenic, 33 for iron, and 18 for manganese. Groundwater in the west-central, northern, and northeastern part of Carson Valley is influenced by geothermal water. Some areas in the county may have septic-tank effluent contaminating the groundwater. Temporal changes in most municipal wells showed no overall trend for dissolved-solids and nitrate concentrations spanning the years 1969-83. However, a municipal well in the Topaz Lake area has shown a general increases in the nitrate concentration from 1961 to 1984, but the concentration does not exceed the drinking-water standard. A future groundwater quality monitoring program in Douglas County would include periodic sampling of primary or heavily pumped wells, long-term trend wells, and supplemental wells. (Thacker-USGS)

Human-health pharmaceutical compounds in Lake Mead, Nevada and Arizona, and Las Vegas Wash, Nevada, October 2000-August 2001

USGS Publications Warehouse

Boyd, Robert A.; Furlong, Edward T.

2002-01-01

The U.S. Geological Survey and the National Park Service conducted a reconnaissance study to investigate the occurrence of selected human-health pharmaceutical compounds in water samples collected from Lake Mead on the Colorado River and Las Vegas Wash, a waterway used to transport treated wastewater from the Las Vegas metropolitan area to Lake Mead. Current research indicates many of these compounds can bioaccumulate and may adversely affect aquatic organisms by disrupting physiological processes, impairing reproductive functions, increasing cancer rates, contributing to the development of antibiotic-resistant strains of bacteria, and acting in undesirable ways when mixed with other substances. These compounds may be present in effluent because a high percentage of prescription and non-prescription drugs used for human-health purposes are excreted from the body as a mixture of parent compounds and degraded metabolite compounds; also, they can be released to the environment when unused products are discarded by way of toilets, sinks, and trash in landfills. Thirteen of 33 targeted compounds were detected in at least one water sample collected between October 2000 and August 2001. All concentrations were less than or equal to 0.20 micrograms per liter. The most frequently detected compounds in samples from Las Vegas Wash were caffeine, carbamazepine (used to treat epilepsy), cotinine (a metabolite of nicotine), and dehydronifedipine (a metabolite of the antianginal Procardia). Less frequently detected compounds in samples collected from Las Vegas Wash were antibiotics (clarithromycin, erythromycin, sulfamethoxazole, and trimethoprim), acetaminophen (an analgesic and anti-inflammatory), cimetidine (used to treat ulcers), codeine (a narcotic and analgesic), diltiazem (an antihypertensive), and 1,7-dimethylxanthine (a metabolite of caffeine). Fewer compounds were detected in samples collected from Lake Mead than from Las Vegas Wash. Caffeine was detected in all samples

Big Soda Lake (Nevada). 3. Pelagic methanogenesis and anaerobic methane oxidation

USGS Publications Warehouse

Iversen, Niels; Oremland, Ronald S.; Klug, Michael J.

1987-01-01

In situ rates of methanogenesis and methane oxidation were measured in meromictic Big Soda Lake. Methane production was measured by the accumulation of methane in the headspaces of anaerobically sealed water samples; radiotracer was used to follow methane oxidation. Nearly all the methane oxidation occurred in the anoxic zones of the lake. Rates of anaerobic oxidation exceeded production at all depths studied in both the mixolimnion (2–6 vs. 0.1–1 nmol liter−1 d−1) and monimolimnion (49–85 vs. 1.6–12 nmol liter−1 d−1) of the lake. Thus, a net consumption of methane equivalent to 1.36 mmol m−2 d−1 occurred in the anoxic water column. Anaerobic methane oxidation had a first-order rate constant of 8.1±0.5 × 10−4 d−1, and activity was eliminated by filter sterilization. However, in situ methane oxidation was of insufficient magnitude to cause a noticeable decrease of ambient dissolved methane levels over an incubation period of 97 h.

The Lake-Catchment (LakeCat) Dataset: Characterizing landscape features for lake basins within the conterminous USA

EPA Science Inventory

Natural and human-related landscape features influence the ecology and water quality within lakes. It is critical, therefore, to quantify landscape features in a hydrologically meaningful way to effectively manage these important ecosystems. Such summaries of the landscape are of...

Magmatism, ash-flow tuffs, and calderas of the ignimbrite flareup in the western Nevada volcanic field, Great Basin, USA

USGS Publications Warehouse

Christopher D. Henry,; John, David A.

2013-01-01

The western Nevada volcanic field is the western third of a belt of calderas through Nevada and western Utah. Twenty-three calderas and their caldera-forming tuffs are reasonably well identified in the western Nevada volcanic field, and the presence of at least another 14 areally extensive, apparently voluminous ash-flow tuffs whose sources are unknown suggests a similar number of undiscovered calderas. Eruption and caldera collapse occurred between at least 34.4 and 23.3 Ma and clustered into five ∼0.5–2.7-Ma-long episodes separated by quiescent periods of ∼1.4 Ma. One eruption and caldera collapse occurred at 19.5 Ma. Intermediate to silicic lavas or shallow intrusions commonly preceded caldera-forming eruptions by 1–6 Ma in any specific area. Caldera-related as well as other magmatism migrated from northeast Nevada to the southwest through time, probably resulting from rollback of the formerly shallow-dipping Farallon slab. Calderas are restricted to the area northeast of what was to become the Walker Lane, although intermediate and effusive magmatism continued to migrate to the southwest across the future Walker Lane.Most ash-flow tuffs in the western Nevada volcanic field are rhyolites, with approximately equal numbers of sparsely porphyritic (≤15% phenocrysts) and abundantly porphyritic (∼20–50% phenocrysts) tuffs. Both sparsely and abundantly porphyritic rhyolites commonly show compositional or petrographic evidence of zoning to trachydacites or dacites. At least four tuffs have volumes greater than 1000 km3, with one possibly as much as ∼3000 km3. However, the volumes of most tuffs are difficult to estimate, because many tuffs primarily filled their source calderas and/or flowed and were deposited in paleovalleys, and thus are irregularly distributed.Channelization and westward flow of most tuffs in paleovalleys allowed them to travel great distances, many as much as ∼250 km (original distance) to what is now the western foothills of the

Hydrography and circulation of ice-marginal lakes at Bering Glacier, Alaska, U.S.A.

USGS Publications Warehouse

Josberger, E.G.; Shuchman, R.A.; Meadows, G.A.; Savage, S.; Payne, J.

2006-01-01

An extensive suite of physical oceanographic, remotely sensed, and water quality measurements, collected from 2001 through 2004 in two ice-marginal lakes at Bering Glacier, Alaska-Berg Lake and Vitus Lake-show that each has a unique circulation controlled by their specific physical forcing within the glacial system. Conductivity profiles from Berg Lake, perched 135 m a.s.l., show no salt in the lake, but the temperature profiles indicate an apparently unstable situation, the 4??C density maximum is located at 10 m depth, not at the bottom of the lake (90 m depth). Subglacial discharge from the Steller Glacier into the bottom of the lake must inject a suspended sediment load sufficient to marginally stabilize the water column throughout the lake. In Vitus Lake, terminus positions derived from satellite imagery show that the glacier terminus rapidly retreated from 1995 to the present resulting in a substantial expansion of the volume of Vitus Lake. Conductivity and temperature profiles from the tidally influenced Vitus Lake show a complex four-layer system with diluted (???50%) seawater in the bottom of the lake. This lake has a complex vertical structure that is the result of convection generated by ice melting in salt water, stratification within the lake, and freshwater entering the lake from beneath the glacier and surface runoff. Four consecutive years, from 2001 to 2004, of these observations in Vitus Lake show little change in the deep temperature and salinity conditions, indicating limited deep water renewal. The combination of the lake level measurements with discharge measurements, through a tidal cycle, by an acoustic Doppler Current Profiler (ADCP) deployed in the Seal River, which drains the entire Bering system, showed a strong tidal influence but no seawater entry into Vitus Lake. The ADCP measurements combined with lake level measurements established a relationship between lake level and discharge, which when integrated over a tidal cycle, gives a

Organic Chemical Concentrations and Reproductive Biomarkers in Common Carp (Cyprinus carpio) Collected from Two Areas in Lake Mead, Nevada, May 1999-May 2000

USGS Publications Warehouse

Goodbred, Steven L.; Leiker, Thomas J.; Patiño, Reynaldo; Jenkins, Jill A.; Denslow, Nancy D.; Orsak, Erik; Rosen, Michael R.

2007-01-01

The U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, National Park Service, Bureau of Reclamation, and Nevada Department of Wildlife, collected and assessed data to determine the general health and reproductive status of common carp (Cyprinus carpio) at two study areas in Lake Mead, Nevada, during May 1999-May 2000. These data will form the basis of interpretations and provide a comparison for continuing studies on the health of the ecosystem in Lake Mead. One study area, Las Vegas Bay, is in the western part of Lake Mead. Las Vegas Bay receives inflows from Las Vegas Wash, which is predominantly tertiary-treated wastewater effluent, and to a lesser extent stormwater runoff from Las Vegas, Henderson, and other nearby communities, and from ground water underlying Las Vegas Valley. The other study area, Overton Arm, is in the northern extent of Lake Mead. Overton Arm receives inflow from the Virgin and Muddy Rivers, which historically are not influenced by wastewater effluent. Both sexes of common carp were collected bimonthly for 12 months using boat-mounted electrofishing gear (a direct electric current is used to temporarily immobilize fish for capture) to determine their health and reproductive status and any relation between these factors and environmental contaminants. This report presents fish tissue chemistry, organic chemical compound concentrations, and biomarker data for 83 male common carp collected from Las Vegas Bay, similar organic chemistry results for 15 male common carp, and similar biomarker measures for 80 male common carp collected from Overton Arm. Tissue chemistry results also are presented for 16 female common carp and biomarker measures for 79 female common carp collected from Las Vegas Bay, and tissue chemistry results for 15 female common carp and biomarker measures for 81 female common carp collected from Overton Arm. Thirty-three organic chemical compounds plus total concentrations for four groups of

High Compressive Stresses Near the Surface of the Sierra Nevada, California

NASA Astrophysics Data System (ADS)

Martel, S. J.; Logan, J. M.; Stock, G. M.

2012-12-01

Observations and stress measurements in granitic rocks of the Sierra Nevada, California reveal strong compressive stresses parallel to the surface of the range at shallow depths. New overcoring measurements show high compressive stresses at three locations along an east-west transect through Yosemite National Park. At the westernmost site (west end of Tenaya Lake), the mean compressive stress is 1.9. At the middle site (north shore of Tenaya Lake) the mean compressive stress is 6.8 MPa. At the easternmost site (south side of Lembert Dome) the mean compressive stress is 3.0 MPa. The trend of the most compressive stress at these sites is within ~30° of the strike of the local topographic surface. Previously published hydraulic fracturing measurements by others elsewhere in the Sierra Nevada indicate surface-parallel compressive stresses of several MPa within several tens of meters of the surface, with the stress magnitudes generally diminishing to the west. Both the new and the previously published compressive stress magnitudes are consistent with the presence of sheeting joints (i.e., "exfoliation joints") in the Sierra Nevada, which require lateral compressive stresses of several MPa to form. These fractures are widespread: they are distributed in granitic rocks from the north end of the range to its southern tip and across the width of the range. Uplift along the normal faults of the eastern escarpment, recently measured by others at ~1-2 mm/yr, probably contributes to these stresses substantially. Geodetic surveys reveal that normal faulting flexes a range concave upwards in response to fault slip, and this flexure is predicted by elastic dislocation models. The topographic relief of the eastern escarpment of the Sierra Nevada is 2-4 km, and since alluvial fill generally buries the bedrock east of the faults, the offset of granitic rocks is at least that much. Compressive stresses of several MPa are predicted by elastic dislocation models of the range front

Parasites of Bloater Coregonus hoyi (Salmonidae) from Lake Michigan, U.S.A

USGS Publications Warehouse

Madenjian, Charles P.; Muzzall, Patrick M.

2013-01-01

In total, 158 bloaters Coregonus hoyi collected in September and October 2011 from 4 Lake Michigan, U.S.A., ports were examined for parasites. The ports included Waukegan (WK), Illinois; Port Washington (PW) and Sturgeon Bay (SB), Wisconsin; and Saugatuck (SG), Michigan. Parasites found in bloaters by port were cestodes Cyathocephalus truncatus (WK, PW, and SB) and Eubothrium salvelini (WK, PW, SB, and SG); the nematode Cystidicola farionis (WK, PW, SB, and SG); acanthocephalans Acanthocephalus dirus (WK and PW), Echinorhynchus salmonis (WK, PW, and SB), and Neoechinorhynchus tumidus (SB); and the copepod Salmincola corpulentus (WK and PW). Gravid individuals of all parasite species were found except for E. salvelini and A. dirus. Cystidicola farionis had the highest prevalence at each port, and the highest mean intensity and mean abundance at PW. The numbers of C. farionis at PW were significantly higher than those at WK and SB. Echinorhynchus salvelini had the highest mean intensities and mean abundances at WK, SB, and SG. The values for parasite species richness in bloaters were similar among ports. The total numbers of parasites were similar between WK and PW, but they were higher at these ports than at SB. The parasite faunas of bloaters were characterized by autogenic helminth species.

Thermal modeling of step-out targets at the Soda Lake geothermal field, Churchill County, Nevada

NASA Astrophysics Data System (ADS)

Dingwall, Ryan Kenneth

Temperature data at the Soda Lake geothermal field in the southeastern Carson Sink, Nevada, highlight an intense thermal anomaly. The geothermal field produces roughly 11 MWe from two power producing facilities which are rated to 23 MWe. The low output is attributed to the inability to locate and produce sufficient volumes of fluid at adequate temperature. Additionally, the current producing area has experienced declining production temperatures over its 40 year history. Two step-out targets adjacent to the main field have been identified that have the potential to increase production and extend the life of the field. Though shallow temperatures in the two subsidiary areas are significantly less than those found within the main anomaly, measurements in deeper wells (>1,000 m) show that temperatures viable for utilization are present. High-pass filtering of the available complete Bouguer gravity data indicates that geothermal flow is present within the shallow sediments of the two subsidiary areas. Significant faulting is observed in the seismic data in both of the subsidiary areas. These structures are highlighted in the seismic similarity attribute calculated as part of this study. One possible conceptual model for the geothermal system(s) at the step-out targets indicated upflow along these faults from depth. In order to test this hypothesis, three-dimensional computer models were constructed in order to observe the temperatures that would result from geothermal flow along the observed fault planes. Results indicate that the observed faults are viable hosts for the geothermal system(s) in the step-out areas. Subsequently, these faults are proposed as targets for future exploration focus and step-out drilling.

Dissolved organic carbon export and internal cycling in small, headwater lakes

USGS Publications Warehouse

Stets, Edward G.; Striegl, Robert G.; Aiken, George R.

2010-01-01

Carbon (C) cycling in freshwater lakes is intense but poorly integrated into our current understanding of overall C transport from the land to the oceans. We quantified dissolved organic carbon export (DOCX) and compared it with modeled gross DOC mineralization (DOCR) to determine whether hydrologic or within-lake processes dominated DOC cycling in a small headwaters watershed in Minnesota, USA. We also used DOC optical properties to gather information about DOC sources. We then compared our results to a data set of approximately 1500 lakes in the Eastern USA (Eastern Lake Survey, ELS, data set) to place our results in context of lakes more broadly. In the open-basin lakes in our watershed (n = 5), DOCX ranged from 60 to 183 g C m−2 lake area yr−1, whereas DOCR ranged from 15 to 21 g C m−2 lake area yr−1, emphasizing that lateral DOC fluxes dominated. DOCX calculated in our study watershed clustered near the 75th percentile of open-basin lakes in the ELS data set, suggesting that these results were not unusual. In contrast, DOCX in closed-basin lakes (n = 2) was approximately 5 g C m−2 lake area yr−1, whereas DOCR was 37 to 42 g C m−2 lake area yr−1, suggesting that internal C cycling dominated. In the ELS data set, median DOCX was 32 and 12 g C m−2 yr−1 in open-basin and closed-basin lakes, respectively. Although not as high as what was observed in our study watershed, DOCX is an important component of lake C flux more generally, particularly in open-basin lakes.

Greenhouse gas fluxes of a shallow lake in south-central North Dakota, USA

USGS Publications Warehouse

Tangen, Brian; Finocchiaro, Raymond; Gleason, Robert A.; Dahl, Charles F.

2016-01-01

Greenhouse gas (GHG) fluxes of aquatic ecosystems in the northern Great Plains of the U.S. represent a significant data gap. Consequently, a 3-year study was conducted in south-central North Dakota, USA, to provide an initial estimate of GHG fluxes from a large, shallow lake. Mean GHG fluxes were 0.02 g carbon dioxide (CO2) m−2 h−1, 0.0009 g methane (CH4) m−2 h−1, and 0.0005 mg nitrous oxide (N2O) m−2 h−1. Fluxes of CO2 and CH4 displayed temporal and spatial variability which is characteristic of aquatic ecosystems, while fluxes of N2O were consistently low throughout the study. Comparisons between results of this study and published values suggest that mean daily fluxes of CO2, CH4, and N2O fromLong Lakewere low, particularly when compared to the well-studied prairie pothole wetlands of the region. Similarly, cumulative seasonal CH4 fluxes, which ranged from 2.68–7.58 g CH4 m−2, were relatively low compared to other wetland systems of North America. The observed variability among aquatic ecosystems underscores the need for further research.

Direct and indirect evidence for earthquakes; an example from the Lake Tahoe Basin, California-Nevada

NASA Astrophysics Data System (ADS)

Maloney, J. M.; Noble, P. J.; Driscoll, N. W.; Kent, G.; Schmauder, G. C.

2012-12-01

High-resolution seismic CHIRP data can image direct evidence of earthquakes (i.e., offset strata) beneath lakes and the ocean. Nevertheless, direct evidence often is not imaged due to conditions such as gas in the sediments, or steep basement topography. In these cases, indirect evidence for earthquakes (i.e., debris flows) may provide insight into the paleoseismic record. The four sub-basins of the tectonically active Lake Tahoe Basin provide an ideal opportunity to image direct evidence for earthquake deformation and compare it to indirect earthquake proxies. We present results from high-resolution seismic CHIRP surveys in Emerald Bay, Fallen Leaf Lake, and Cascade Lake to constrain the recurrence interval on the West Tahoe Dollar Point Fault (WTDPF), which was previously identified as potentially the most hazardous fault in the Lake Tahoe Basin. Recently collected CHIRP profiles beneath Fallen Leaf Lake image slide deposits that appear synchronous with slides in other sub-basins. The temporal correlation of slides between multiple basins suggests triggering by events on the WTDPF. If correct, we postulate a recurrence interval for the WTDPF of ~3-4 k.y., indicating that the WTDPF is near its seismic recurrence cycle. In addition, CHIRP data beneath Cascade Lake image strands of the WTDPF that offset the lakefloor as much as ~7 m. The Cascade Lake data combined with onshore LiDAR allowed us to map the geometry of the WTDPF continuously across the southern Lake Tahoe Basin and yielded an improved geohazard assessment.

Potential for Loss of Breeding Habitat for Imperiled Mountain Yellow-legged Frog ( Rana muscosa) in High Sierra Nevada Mountain Water Bodies due to Reduced Snowpack: Interaction of Climate Change and an Introduced Predator

NASA Astrophysics Data System (ADS)

Lacan, I.; Matthews, K. R.

2005-12-01

Year to year variation in snowpack (20-200% average) and summer rain create large fluctuations in the volume of water in ponds and small lakes of the higher elevation (> 3000 m) Sierra Nevada. These water bodies are critical habitat for the imperiled mountain yellow-legged frog, Rana muscosa, which has decreased in abundance by 90% during the past century, due in part to the loss of suitable habitat and introduction of a fish predator (trout, Oncorhynchus spp.). Climate change is predicted to reduce the amount of snowpack, potentially impacting amphibian habitats throughout the Sierra Nevada by further reducing the lake and pond water levels and resulting in drying of small lakes during the summer. Mountain yellow-legged frogs are closely tied to water during all life stages, and are unique in having a three- to four-year tadpole phase. Thus, tadpole survival and future recruitment of adult frogs requires adequate water in lakes and ponds throughout the year, but larger lakes are populated with fish that prey on frogs and tadpoles. Thus, most successful frog breeding occurs in warm, shallow, fishless ponds that undergo wide fluctuations in volume. These water bodies would be most susceptible to the potential climate change effects of reduced snowpack, possibly resulting in lower tadpole survival. This study explores the link between the changes in water availability -- including complete pond drying -- and the abundance and recruitment of mountain yellow-legged frog in Dusy Basin, Kings Canyon National Park, California, USA. We propose using the low-snowpack years (1999, 2002, 2004) as comparative case studies to predict future effects of climate change on aquatic habitat availability and amphibian abundance and survival. To quantify the year to year variation and changes in water volume available to amphibians, we initiated GPS lake mapping in 2002 to quantify water volumes, water surface area, and shoreline length. We tracked these changes by repeated mapping of

Chemical and biological characteristics of Emerald Lake and the streams in its watershed and the responses of the lake and streams to acidic deposition. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Melack, J.M.; Cooper, S.D.; Jenkins, T.M.

1989-03-14

This report describes the results of field work conducted at Emerald Lake in Sequoia National Park during the period of 1983-88, with an emphasis on the effects of acid deposition on a high-elevation lake in the Sierra Nevada. Time-series data were collected for major ions, nutrients, trace metals, chlorophyll, zooplankton and zoobenthos. Mass balances were calculated for major solutes in the lake, including analysis of the inflows and major solutes in the lake, including analysis of the inflows and outflow from the lake. The ecology and population dynamics of the resident population of brook trout were studied in detail. Biologicalmore » surveys indicated the presence of the Pacific tree frog in small ponds in the vicinity of Emerald Lake. Experimental acidification of large bags in the lake was used to develop dose-response relationships for the major zooplankton species, especially Daphnia. The conclusion of the research to date is that Emerald Lake is not currently showing serious chemical or biological effects of acidification. Acid-sensitive animals are found in the lake and associated streams. The surface waters of the Emerald Basin are extremely dilute and ANC-generating processes in the lake are small compared to that of the watershed. Acidic episodes have been recorded. If these episodes were to increase, the surface waters and the biological populations could be readily affected.« less

Aerosol Light Absorption and Scattering at Four Sites in and Near Mexico City: Comparison with Las Vegas, Nevada, USA

NASA Astrophysics Data System (ADS)

Arnott, W. P.; Miranda, G. P.; Gaffney, J. S.; Marley, N. A.

2007-05-01

Four photoacoustic spectrometers (PAS) for aerosol light scattering and absorption measurements were deployed in and near Mexico City in March 2006 as part of the Megacity Impacts on Regional and Global Environments (MIRAGE). The four sites included: an urban site at Instituto Mexicano del Petroleo (Mexican Oil Institute, denoted by IMP); a suburban site at the Technological University of Tecamac; a rural site at "La Biznaga" ranch; and a site at the Paseo de Cortes (altitude 3,810 meters ASL) in the rural area above Amecameca in the State of Mexico, on the saddle between the volcanoes Popocatepetl and Iztaccihuatl. A similar campaign was held in Las Vegas, Nevada, USA in January-February, 2003. The IMP site gave in-situ characterization of the Mexico City plume under favorable wind conditions while the other sites provided characterization of the plume, mixed in with any local sources. The second and third sites are north of Mexico City, and the fourth site is south. The PAS used at IMP operates at 532 nm, and conveniently allowed for characterization of gaseous absorption at this wavelength as well. Instruments at the second and third sites operate at 870 nm, and the one at the fourth site at 780 nm. Light scattering measurements are accomplished within the PAS by the reciprocal nephelometery method. In the urban site the aerosol absorption coefficient typically varies between 20 and 180 Mm-1 during the course of the day and significant diurnal variation of the aerosol single scattering albedo was observed probably as a consequence of secondary aerosol formation. Comparisons with TSI nephelometer scattering at the T0 site will be presented. We will present the diurnal variation of the scattering and absorption as well as the single scattering albedo and fraction of absorption due to gases at the IMP site and compare with Las Vegas diurnal variation. Mexico City 'breaths' more during the course of the day than Las Vegas, Nevada in part because the latitude of

Chicago, Illinois, USA

NASA Image and Video Library

1990-03-04

In this late winter scene of Chicago, Illinois, USA (41.5N, 87.0W) the light dusting of snow has actually enhanced the determination of the cities street pattern, parks and other cultural features. Sited at the south end of Lake Michigan, Chicago has long served as an industrial, transportation and communications center for the midwest. The obvious snowline on the ground enables meteorologists to trace the regional groundtracks of winter storms.

Decline of the world's saline lakes

NASA Astrophysics Data System (ADS)

Wurtsbaugh, Wayne A.; Miller, Craig; Null, Sarah E.; Derose, R. Justin; Wilcock, Peter; Hahnenberger, Maura; Howe, Frank; Moore, Johnnie

2017-11-01

Many of the world's saline lakes are shrinking at alarming rates, reducing waterbird habitat and economic benefits while threatening human health. Saline lakes are long-term basin-wide integrators of climatic conditions that shrink and grow with natural climatic variation. In contrast, water withdrawals for human use exert a sustained reduction in lake inflows and levels. Quantifying the relative contributions of natural variability and human impacts to lake inflows is needed to preserve these lakes. With a credible water balance, causes of lake decline from water diversions or climate variability can be identified and the inflow needed to maintain lake health can be defined. Without a water balance, natural variability can be an excuse for inaction. Here we describe the decline of several of the world's large saline lakes and use a water balance for Great Salt Lake (USA) to demonstrate that consumptive water use rather than long-term climate change has greatly reduced its size. The inflow needed to maintain bird habitat, support lake-related industries and prevent dust storms that threaten human health and agriculture can be identified and provides the information to evaluate the difficult tradeoffs between direct benefits of consumptive water use and ecosystem services provided by saline lakes.

Late Quaternary megafloods from Glacial Lake Atna, Southcentral Alaska, U.S.A.

NASA Astrophysics Data System (ADS)

Wiedmer, Michael; Montgomery, David R.; Gillespie, Alan R.; Greenberg, Harvey

2010-05-01

Geomorphic, stratigraphic, geotechnical, and biogeographic evidence indicate that failure of a Pleistocene ice dam between 15.5 and 26 ka generated a megaflood from Glacial Lake Atna down the Matanuska Valley. While it has long been recognized that Lake Atna occupied ≥ 9000 km 2 of south-central Alaska's Copper River Basin, little attention has focused on the lake's discharge locations and behaviors. Digital elevation model and geomorphic analyses suggest that progressive lowering of the lake level by decanting over spillways exposed during glacial retreat led to sequential discharges down the Matanuska, Susitna, Tok, and Copper river valleys. Lake Atna's size, ˜ 50 ka duration, and sequential connection to four major drainages likely made it a regionally important late Pleistocene freshwater refugium. We estimate a catastrophic Matanuska megaflood would have released 500-1400 km 3 at a maximum rate of ≥ 3 × 10 6 m 3 s - 1 . Volumes for the other outlets ranged from 200 to 2600 km 3 and estimated maximum discharges ranged from 0.8 to 11.3 × 10 6 m 3 s - 1 , making Lake Atna a serial generator of some of the largest known freshwater megafloods.

Repeated sedimentation and exposure of glacial Lake Missoula sediments: A lake-level history at Garden Gulch, Montana, USA

NASA Astrophysics Data System (ADS)

Smith, Larry N.

2017-01-01

Glaciolacustrine sediments record lake transgression, regression, and subaerial modification of the silty lake-bottom of glacial Lake Missoula in the Clark Fork River valley. The sequence preserved at Garden Gulch, MT documents lake-level fluctuations at >65% of its full-pool volume. Twelve sedimentary cycles fine upwards from (1) very fine-grained sandy silt to (2) silt with climbing ripples to (3) rhythmically laminated silt and some clay. The cycles are fine-grained turbidites capped locally by thin layers of angular gravel derived from local bedrock outcrops. The gravels appear to be the toes of mass wasting lobes carried onto the exposed lakebed surface during repeated lake-level lowerings. Periglacial wedges, small rotational faults, involutions, and clastic dikes deform the tops of eleven cycles. The wedges are 10-30 cm wide, penetrate 30-70 cm deep, are spaced <1 m apart, and contain vertically oriented gravel and massive to laminated sediment. Wedges split and taper in plan view. A few thin silt-filled dikes, which branch and taper downwards from wedges, are interpreted as filled frost cracks. One 10-20 cm-wide sand-filled dike protrudes upward from a sand bed; it is interpreted as a liquefaction feature consistent with a filling and draining lake. The deformed cycle tops preserve evidence of periglacial cold, subaerial exposure, seasonal frost heave, and the incipient formation of sorted polygons. The lowest five cycles are thicker and display more periglacial modification at their tops than the upper seven cycles. The Garden Gulch section may represent as few as seven and as many as twelve substantial fillings and partial to complete drainings of glacial Lake Missoula.

Comparing CMIP-3 and CMIP-5 climate projections on flooding estimation of Devils Lake of North Dakota, USA.

PubMed

Kharel, Gehendra; Kirilenko, Andrei

2018-01-01

Water level fluctuations in endorheic lakes are highly susceptible to even slight changes in climate and land use. Devils Lake (DL) in North Dakota, USA is an endorheic system that has undergone multi-decade flooding driven by changes in regional climate. Flooding mitigation strategies have centered on the release of lake water to a nearby river system through artificial outlets, resulting in legal challenges and environmental concerns related to water quality, downstream flooding, species migration, stakeholder opposition, and transboundary water conflicts between the US and Canada. Despite these drawbacks, running outlets would result in low overspill risks in the next 30 years. In this study we evaluated the efficacy of this outlet-based mitigation strategy under scenarios based on the latest IPCC future climate projections. We used the Coupled Model Intercomparison Project CMIP-5 weather patterns from 17 general circulation models (GCMs) obtained under four representative concentration pathways (RCP) scenarios and downscaled to the DL region. Then, we simulated the changes in lake water levels using the soil and water assessment tool based hydrological model of the watershed. We estimated the probability of future flood risks under those scenarios and compared those with previously estimated overspill risks under the CMIP-3 climate. The CMIP-5 ensemble projected a mean annual temperature of 5.78 °C and mean daily precipitation of 1.42 mm/day; both are higher than the existing CMIP-3 future estimates of 4.98 °C and 1.40 mm/day, respectively. The increased precipitation and higher temperature resulted in a significant increase of DL's overspill risks: 24.4-47.1% without release from outlets and 3.5-14.4% even if the outlets are operated at their combined full 17 m 3 /s capacity. The modeled increases in overspill risks indicate a greater frequency of water releases through the artificial outlets. Future risk mitigation management should include providing a

Mercury in Tadpoles Collected from Remote Alpine Sites in the Southern Sierra Nevada Mountains, California, USA

EPA Science Inventory

Amphibians in alpine wetlands of the Sierra Nevada mountains comprise key components of an aquatic-terrestrial food chain, and mercury contamination is a concern because concentrations in fish from this regin exceed thresholds of risk to piscivorous wildlife. Total mercury conc...

ANALYSIS OF LOW-LEVEL PESTICIDES FROM HIGH-ELEVATION LAKE WATERS BY LARGE-VOLUME INJECTION GCMS

EPA Science Inventory

Pesticides are among the factors being proposed as causal agents for amphibian population declines in the Sierra Nevada range of California, USA. We hypothesize that agricultural pesticides applied in the San Joaquin Valley west of the mountains are volatilized or eroded, transpo...

Metabolism of nonparticulate phosphorus in an acid bog lake

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koenings, J. P.

1977-01-01

In North Gate Lake, an acid bog lake located on the northern Michigan-Wisconsin border, U.S.A., the algal nutrient inorganic phosphate (FRP) is not detectable by chemical means. Organic phosphorus (FUP) represents 100% of the detectable filterable phosphorus. The availability and cycling of this organic fraction are of considerable interest in regard to the primary productivity of this system. To clarify these relationships, the cycling of nonparticulate forms of phosphorus found in the epilimnion of this lake was studied.

Snowmelt timing, phenology, and growing season length in conifer forests of Crater Lake National Park, USA

NASA Astrophysics Data System (ADS)

O'Leary, Donal S.; Kellermann, Jherime L.; Wayne, Chris

2018-02-01

Anthropogenic climate change is having significant impacts on montane and high-elevation areas globally. Warmer winter temperatures are driving reduced snowpack in the western USA with broad potential impacts on ecosystem dynamics of particular concern for protected areas. Vegetation phenology is a sensitive indicator of ecological response to climate change and is associated with snowmelt timing. Human monitoring of climate impacts can be resource prohibitive for land management agencies, whereas remotely sensed phenology observations are freely available at a range of spatiotemporal scales. Little work has been done in regions dominated by evergreen conifer cover, which represents many mountain regions at temperate latitudes. We used moderate resolution imaging spectroradiometer (MODIS) data to assess the influence of snowmelt timing and elevation on five phenology metrics (green up, maximum greenness, senescence, dormancy, and growing season length) within Crater Lake National Park, Oregon, USA from 2001 to 2012. Earlier annual mean snowmelt timing was significantly correlated with earlier onset of green up at the landscape scale. Snowmelt timing and elevation have significant explanatory power for phenology, though with high variability. Elevation has a moderate control on early season indicators such as snowmelt timing and green up and less on late-season variables such as senescence and growing season length. PCA results show that early season indicators and late season indicators vary independently. These results have important implications for ecosystem dynamics, management, and conservation, particularly of species such as whitebark pine ( Pinus albicaulis) in alpine and subalpine areas.

Depth as an organizer of fish assemblages in floodplain lakes

USGS Publications Warehouse

Miranda, L.E.

2011-01-01

Depth reduction is a natural process in floodplain lakes, but in many basins has been accelerated by anthropogenic disturbances. A diverse set of 42 floodplain lakes in the Yazoo River Basin (Mississippi, USA) was examined to test the hypothesis of whether depth reduction was a key determinant of water quality and fish assemblage structure. Single and multiple variable analyses were applied to 10 commonly monitored water variables and 54 fish species. Results showed strong associations between depth and water characteristics, and between depth and fish assemblages. Deep lakes provided less variable environments, clearer water, and a wider range of microhabitats than shallow lakes. The greater environmental stability was reflected by the dominant species in the assemblages, which included a broader representation of large-body species, species less tolerant of extreme water quality, and more predators. Stability in deep lakes was further reflected by reduced among-lake variability in taxa representation. Fish assemblages in shallow lakes were more variable than deep lakes, and commonly dominated by opportunistic species that have early maturity, extended breeding seasons, small adult size, and short lifespan. Depth is a causal factor that drives many physical and chemical variables that contribute to organizing fish assemblages in floodplain lakes. Thus, correlations between fish and water transparency, temperature, oxygen, trophic state, habitat structure, and other environmental descriptors may ultimately be totally or partly regulated by depth. In basins undergoing rapid anthropogenic modifications, local changes forced by depth reductions may be expected to eliminate species available from the regional pool and could have considerable ecological implications. ?? 2010 Springer Basel AG (outside the USA).

Thermal and hydrologic attributes of rock glaciers and periglacial talus landforms: Sierra Nevada, California, USA

Treesearch

Constance I. Millar; Robert D. Westfall; Diane L. Delany

2013-01-01

To explore thermal regimes and hydrologic capacity of rock glaciers and related periglacial talus landforms, mini-thermochrons were deployed in and around potentially ice-embedded features of the Sierra Nevada. Results from pilot studies at 13 rock glaciers and 7 taluses indicate that outlet springs from these landforms generally do not desiccate but persist year...

Temporal and Spatial Variation of Atmospherically Deposited Organic Contaminants at High Elevation in Yosemite National Park, California, USA

EPA Science Inventory

Atmospherically deposited organic contaminants in the Sierra Nevada mountains of California, USA, have exceeded some thresholds of concern, but the spatial and temporal distributions of contaminants in the mountains are not well known. The present study evaluated (1) whether the...

Studies of quaternary saline lakes-II. Isotopic and compositional changes during desiccation of the brines in Owens Lake, California, 1969-1971

USGS Publications Warehouse

Friedman, I.; Smith, G.I.; Hardcastle, Kenneth G.

1976-01-01

Owens Lake is an alkaline salt lake in a closed basin in southeast California. It is normally nearly dry, but in early 1969, an abnormal runoff from the Sierra Nevada flooded it to a maximum depth of 2??4 m. By late summer of 1971, the lake was again nearly dry and the dissolved salts recrystallized. Changes in the chemistry, pH, and deuterium content were monitored during desiccation. During flooding, salts (mostly trona, halite, and burkeite) dissolved slowly from the lake floor. Their concentration in the lake waters increased as evaporation removed water and salts again crystallized, but winter temperatures caused precipitation of some salts and the following summer warming caused their solution, resulting in seasonal variations in the concentration patterns of some ions. The pH values (9??4-10??4) changed with time but showed no detectable diurnal pattern. The deuterium concentration increased during evaporation and appeared to be in equilibrium with vapor leaving the lake according to the Rayleigh equation. The effective ??(D/H in liquid/D/H in vapor) decreased as salinity increased; the earliest measured value was 1??069 [as total dissolved solids (TDS) of lake waters changed from 136,200 to 250,400 mg/1]and the last value (calc.) was 1??025 (as TDS changed from 450,000 to 470,300 mg/1). Deuterium exchange with the atmosphere was apparently small except during late desiccation stages when the isotopic contrast became great. Eventually, atmospheric exchange, combined with decreasing ?? and lake size and increasing salinity, stopped further deuterium concentration in the lake. The maximum contrast between atmospheric vapor and lake deuterium contents was about 110%. ?? 1976.

Limnological data for Donner Lake, California, May 1973 through December 1973

USGS Publications Warehouse

Dong, Alex E.

1975-01-01

Donner Lake is easily accessible to the metropolitan areas of Sacramento and San Francisco and is close to many recreational areas in the Sierra Nevada. The lake is used for recreation and is bordered by commercial establishments, summer vacation homes, and a large state campground. Domestic wastes around the lake have received only septic tank treatment. A sewerage system under construction and partly in use at the time of this study has been completed and now (January 1975) all domestic wastes are transported out of the basin.In September of 1969 and 1970, a brief survey of the lake was conducted (Iwatsubo and others, 1972, p. 28). The results of that study indicated a well-established thermocline between 33 and 66 ft (10 and 20 m). A subsurface maximum in the dissolved-oxygen concentration occurred between 46 and 66 ft (14 and 20 m). In the shallow littoral zone, periphyton and patches of submerged rooted plants were visible.In order to remain attractive for recreational use, Donner Lake will require sound management. A thorough understanding of the water quality in the lake and the quality of inflow and outflow is of paramount importance.

Evolution of glacier-dammed lakes through space and time; Brady Glacier, Alaska, USA

NASA Astrophysics Data System (ADS)

Capps, Denny M.; Clague, John J.

2014-04-01

Glacier-dammed lakes and their associated jökulhlaups cause severe flooding in downstream areas and substantially influence glacier dynamics. Brady Glacier in southeast Alaska is well suited for a study of these phenomena because it presently dams 10 large (> 1 km2) lakes. Our objectives are to demonstrate how Brady Glacier and its lakes have co-evolved in the past and to apply this knowledge to predict how the glacier and its lakes will likely evolve in the future. To accomplish these objectives, we georeferenced a variety of maps, airphotos, and optical satellite imagery to characterize the evolution of the glacier and lakes. We also collected bathymetry data and created bathymetric maps of select lakes. Despite small advances and retreats, the main terminus of Brady Glacier has changed little since 1880. However, it downwasted at rates of 2-3 m/y between 1948 and 2000, more than the regional average. The most dramatic retreat (2 km) and downwasting (120 m) have occurred adjacent to glacier-dammed lakes and are primarily the result of calving. Brady Glacier is a former tidewater glacier. With continued downwasting, Brady Glacier may return to a tidewater regime and enter into a phase of catastrophic retreat. The situation at Brady Glacier is not unique, and the lessons learned here can be applied elsewhere to identify future glacier-dammed lakes, jökulhlaups, and glacier instability.

Organochlorine and trace element contamination in wintering and migrating diving ducks in the southern Great Lakes, USA, since the zebra mussel invasion

USGS Publications Warehouse

Custer, Christine M.; Custer, T.W.

2000-01-01

Because of the potential for increased trophic transfer of contaminants by zebra mussels (Dreissena sp.) to higher trophic levels, we collected four species of waterfowl (n = 65 ducks) from four locations in Lake Erie, Lake St. Clair, and Lake Michigan, USA, between 1991 and 1993 for organochlorine contaminant and trace element analyses. Geometric mean concentrations of total polychlorinated biphenyls (PCBs) and p,pa??-dichlorodiphenyldichloroethylene (DDE) were 1.35 and 0.15 I?g/g wet weight in lesser scaup (Aythya affinis) carcasses and were below known effect levels. Total PCBs in 80% of carcasses, however, were above the U.S. Food and Drug Administration's threshold of 3.0 I?g/g lipid weight for consumption of poultry. With the exception of selenium, trace elements were also at background or no-effect levels. Selenium concentrations in livers of 95% of lesser scaup, 90% of bufflehead (Bucephala albeola), and 72% of common goldeneye (Bucephala clangula) were in the elevated (>10 I?g/g dry wt) or potentially harmful range (>33 I?g/g dry wt). The effects of these high selenium concentrations are unknown but should be investigated further based on reproductive effects observed in field and laboratory studies of dabbling ducks and because lesser scaup populations are declining. Concentrations of total PCBs in dreissenid mussels in western Lake Erie were 10 times higher than in the upper Mississippi River but were similar to concentrations in other industrialized rivers in Europe and the United States. Metal concentrations were similar to other industrialized sites where zebra mussels have been sampled.

Holocene glaciation of the central Sierra Nevada, California

NASA Astrophysics Data System (ADS)

Bowerman, Nicole D.; Clark, Douglas H.

2011-05-01

Sediment cores from two bedrock-dammed lakes in North Fork Big Pine Creek, Sierra Nevada, California, preserve the most detailed and complete record of Holocene glaciation yet recovered in the region. The lakes are fed by outwash from the Palisade Glacier, the largest (˜1.3 km 2) and presumably longest-lived glacier in the range, and capture essentially all of the rock flour it produces. Distinct late-Holocene (Matthes) and late-Pleistocene (Recess Peak) moraines lie between the modern glacier and the lakes. The lakes have therefore received continuous sedimentation from the basin since the retreat of the Tioga glacier (Last Glacial Maximum) and capture rock flour related to all post-LGM advances. A total of eight long cores (up to 5.5 m sediment depth) and one short surface sediment short core preserve a coherent record of fluctuating rock flour flux to the lakes through the Holocene. Age constraints on rock flour spikes in First and Second lakes based on 31 14C-dated macrofossils indicate Holocene glaciation began ˜3200 cal yr B P, followed by a possible glacier maximum at ˜2800 cal yr B P and four distinct glacier maxima at ˜2200, ˜1600, ˜700 and ˜250-170 cal yr. B.P., the most recent maximum being the largest. Reconstruction of the equilibrium-line altitudes (ELA) associated with each distinct advance recorded in the moraines (Recess Peak, Matthes, and modern) indicates ELA depressions (relative to modern) of ˜250 m and 90 m for Recess Peak and Matthes advances, respectively. These differences represent decreases in summer temperatures of 1.7-2.8 °C (Recess Peak) and 0.2-2° (Matthes), and increases in winter precipitation of 22-34 cm snow water equivalent (s.w.e.) (Recess Peak) and 3-26 cm s.w.e. (Matthes) compared to modern conditions. Although small, these changes are significant and similar to those noted in the Cascade Range to the north, and represent a significant departure from historical climate trends in the region.

Nevada NPDES Permits

EPA Pesticide Factsheets

In Nevada, EPA’s Pacific Southwest (Region 9) issues all NPDES permits for any discharges on tribal lands. All other NPDES permits are issued by the Nevada Division of Environmental Protection (NDEP).

Mineralogy and geochemistry of two metamorphosed sedimentary manganese deposits, Sierra Nevada, California, USA

USGS Publications Warehouse

Flohr, M.J.K.; Huebner, J.S.

1992-01-01

Laminated to massive rhodochrosite, hausmannite, and Mn-silicates from the Smith prospect and Manga-Chrome mine, Sierra Nevada, California were deposited as ocean floor sediments associated with chert and shale. The principal lithologies at Smith are chert, argillite, rhodochrosite-, hausmannite- and chlorite-rich layers, and relatively uncommon layers of jacobsite. The Manga-Chrome mine also contains layers rich in manganoan calcite and caryopilite. Tephroite, rhodonite, spessartine, and accessory alleghanyite and sonolite formed during metamorphism. Volcaniclastic components are present at Manga-Chrome as metavolcanic clasts and as Mn-poor, red, garnet- and hematite-rich layers. There is no evidence, such as relict lithologies, that Mn was introduced into Mn-poor lithologies such as chert, limestone or mudstone. Replacement of Mn-poor phases by Mn-rich phases is observed only in the groundmass of volcanic clasts that appear to have fallen into soft Mn-rich mud. Manganiferous samples from the Smith prospect and Manga-Chrome mine have high Mn Fe and low concentrations of Ni, Cu, Zn, Co, U, Th and the rare-earth elements that are similar to concentrations reported from other ancient Mn deposits found in chert-greenstone complexes and from manganiferous sediments and crusts that are forming near modern sea floor vents. The Sierra Nevada deposits formed as precipitates of Mn-rich sediments on the sea floor, probably from mixtures of circulating hydrothermal fluids and seawater. The composition of a metabasalt from the Smith prospect is consistent with those of island-arc tholeiites. Metavolcanic clasts from the Manga-Chrome mine are compositionally distinct from the Smith metabasalt and have alkaline to calc-alkaline affinities. A back-arc basin is considered to be the most likely paleoenvironment for the formation of the Mn-rich lenses at the Manga-Chrome mine and, by association, the Smith prospect. Layers of rhodochrosite, hausmannite and chert preserve the

Avian botulism and avian chlamydiosis in wild water birds, Benton Lake National Wildlife Refuge, Montana, USA

USGS Publications Warehouse

Docherty, Douglas E.; Franson, J. Christian; Brannian, Roger E.; Long, Renee R.; Radi, Craig A.; Krueger, David; Johnson, Robert F.

2012-01-01

In 1999, the U.S. Geological Survey (USGS) National Wildlife Health Center, Madison, Wisconsin, conducted a diagnostic investigation into a water bird mortality event involving intoxication with avian botulism type C and infection with avian chlamydiosis at the Benton Lake National Wildlife Refuge in Montana, USA. Of 24 carcasses necropsied, 11 had lesions consistent with avian chlamydiosis, including two that tested positive for infectious Chlamydophila psittaci, and 12 were positive for avian botulism type C. One bird tested positive for both avian botulism type C and C. psittaci. Of 61 apparently healthy water birds sampled and released, 13 had serologic evidence of C. psittaci infection and 7 were, at the time of capture, shedding infectious C. psittaci via the cloacal or oropharyngeal route. Since more routinely diagnosed disease conditions may mask avian chlamydiosis, these findings support the need for a comprehensive diagnostic investigation when determining the cause of a wildlife mortality event.

Phytoplankton assemblages in high-elevation lakes in the northern Cascade Mountains, Washington State, USA

USGS Publications Warehouse

Larson, Gary L.; McIntire, C.D.; Truitt, R.E.; Liss, W.J.; Hoffman, Robert L.; Deimling, E.; Lomnicky, G.A.

1998-01-01

Phytoplankton assemblages in high-elevation lakes of North Cascades National Park Service Complex were studied during the open-water period in 1989. Collectively, 93 taxa were identified in 55 samples from 51 lakes. Based on cell densities, cyanobacteria had the highest relative abundance (36.7 %), followed by chlorophytes (29.8 %), and chrysophytes (19.6 %). Aphanocapsa delicatissima had the highest proportional abundance (14.0 %). Only 15.1 % percent of the taxa occurred in more than 20 samples. Phytoplankton cell densities increased following a gradient of increasing lake-water temperature, alkalinity, and concentration of total Kjeldahl-N with decreasing lake elevation. Chrysophytes and cyanobacteria were quantitatively (relative abundance) the most important taxa in alpine and subalpine lakes, whereas cyanobacteria had the highest relative abundances in high-forest and low-forest lakes. Chlorophytes had their highest relative abundance in high-forest lakes. Although low in relative abundance, diatoms and dinoflagellates were most abundant in alpine lakes. An ordination by correspondence analysis indicated that most alpine, subalpine, and high-forest lakes had similar floras. Although a few subalpine lakes exhibited deviations from this pattern, the main differences in phytoplankton composition were found in a group of low-forest and high-forest lakes. Canonical correspondence analysis (CCA) provided evidence that the distribution of samples and taxa in ordination space was correlated with a gradient of decreasing lake elevation and increasing water temperature, alkalinity, and concentration of nitrogen. When CCA was used to examine relationships among phytoplankton taxa and vegetation zones, a continuous distribution of taxa was found from the low-forest zone to the subalpine zone, with a large number of taxa occurring primarily in the subalpine and high-forest zones. Three phytoplankton taxa occurred primarily in alpine lakes, whereas five taxa co-occurred in

Population dynamics and evaluation of alternative management strategies for nonnative Lake Trout in Priest Lake, Idaho

USGS Publications Warehouse

Ng, Elizabeth L.; Fredericks, Jim P.; Quist, Michael C.

2016-01-01

Lake Trout Salvelinus namaycush have been introduced widely throughout the western USA to enhance recreational fisheries, but high predatory demand can create challenges for management of yield and trophy fisheries alike. Lake Trout were introduced to Priest Lake, Idaho, during the 1920s, but few fishery-independent data are available to guide current or future management actions. We collected fishery-independent data to describe population dynamics and evaluate potential management scenarios using an age-structured population model. Lake Trout in Priest Lake were characterized by fast growth at young ages, which resulted in young age at maturity. However, adult growth rates and body condition were lower than for other Lake Trout populations. High rates of skipped spawning (>50%) were also observed. Model projections indicated that the population was growing (λ = 1.03). Eradication could be achieved by increasing annual mortality to 0.32, approximately twice the current rate. A protected slot length limit could increase population length-structure, but few fish grew fast enough to exit the slot. In contrast, a juvenile removal scenario targeting age-2 to age-5 Lake Trout maintained short-term harvest of trophy-length individuals while reducing overall population abundance.

Delineating a road-salt plume in lakebed sediments using electrical resistivity, piezometers, and seepage meters at Mirror Lake, New Hampshire, U.S.A

USGS Publications Warehouse

Toran, Laura; Johnson, Melanie; Nyquist, Jonathan E.; Rosenberry, Donald O.

2010-01-01

Electrical-resistivity surveys, seepage meter measurements, and drive-point piezometers have been used to characterize chloride-enriched groundwater in lakebed sediments of Mirror Lake, New Hampshire, U.S.A. A combination of bottom-cable and floating-cable electrical-resistivity surveys identified a conductive zone (<100ohm-m)">(<100ohm-m)(<100ohm-m) overlying resistive bedrock (<1000ohm-m)">(<1000ohm-m)(<1000ohm-m)beneath the lake. Shallow pore-water samples from piezometers in lakebed sediments have chloride concentrations of 200–1800μeq/liter">200–1800μeq/liter200–1800μeq/liter, and lake water has a chloride concentration of 104μeq/liter">104μeq/liter104μeq/liter. The extent of the plume was estimated and mapped using resistivity and water-sample data. The plume (20×35m">20×35m20×35m wide and at least 3m">3m3m thick) extends nearly the full length and width of a small inlet, overlying the top of a basin formed by the bedrock. It would not have been possible to mapthe plume's shape without the resistivity surveys because wells provided only limited coverage. Seepage meters were installed approximately 40m">40m40m from the mouth of a small stream discharging at the head of the inlet in an area where the resistivity data indicated lake sediments are thin. These meters recorded in-seepage of chloride-enriched groundwater at rates similar to those observed closer to shore, which was unexpected because seepage usually declines away from shore. Although the concentration of road salt in the northeast inlet stream is declining, the plume map and seepage data indicate the groundwater contribution of road salt to the lake is not declining. The findings demonstrate the benefit of combining geophysical and hydrologic data to characterize discharge of a plume beneath Mirror Lake. The extent of the plume in groundwater beneath the lake and stream indicate there will likely be a long-term source of chloride to the lake from groundwater.

Numerical simulation of the paleohydrology of glacial Lake Oshkosh, eastern Wisconsin, USA

USGS Publications Warehouse

Clark, J.A.; Befus, K.M.; Hooyer, T.S.; Stewart, P.W.; Shipman, T.D.; Gregory, C.T.; Zylstra, D.J.

2008-01-01

Proglacial lakes, formed during retreat of the Laurentide ice sheet, evolved quickly as outlets became ice-free and the earth deformed through glacial isostatic adjustment. With high-resolution digital elevation models (DEMs) and GIS methods, it is possible to reconstruct the evolution of surface hydrology. When a DEM deforms through time as predicted by our model of viscoelastic earth relaxation, the entire surface hydrologic system with its lakes, outlets, shorelines and rivers also evolves without requiring assumptions of outlet position. The method is applied to proglacial Lake Oshkosh in Wisconsin (13,600 to 12,900??cal yr BP). Comparison of predicted to observed shoreline tilt indicates the ice sheet was about 400??m thick over the Great Lakes region. During ice sheet recession, each of the five outlets are predicted to uplift more than 100??m and then subside approximately 30??m. At its maximum extent, Lake Oshkosh covered 6600??km2 with a volume of 111??km3. Using the Hydrologic Engineering Center-River Analysis System model, flow velocities during glacial outburst floods up to 9??m/s and peak discharge of 140,000??m3/s are predicted, which could drain 33.5??km3 of lake water in 10??days and transport boulders up to 3??m in diameter. ?? 2007 University of Washington.

Tree-ring reconstruction of the level of Great Salt Lake, USA

Treesearch

R. Justin DeRose; Shih-Yu Wang; Brendan M. Buckley; Matthew F. Bekker

2014-01-01

Utah's Great Salt Lake (GSL) is a closed-basin remnant of the larger Pleistocene-age Lake Bonneville. The modern instrumental record of the GSL-level (i.e. elevation) change is strongly modulated by Pacific Ocean coupled ocean/atmospheric oscillations at low frequency, and therefore reflects the decadalscale wet/dry cycles that characterize the region. A within-...

Sedimentary sulfur geochemistry of the Paleogene Green River Formation, western USA: Implications for interpreting depositional and diagenetic processes in saline alkaline lakes

USGS Publications Warehouse

Tuttle, M.L.; Goldhaber, M.B.

1993-01-01

The sulfur geochemistry of the lacustrine Paleogene Green River Formation (Colorado, Utah, and Wyoming, USA) is unlike that of most marine and other lacustrine rocks. Distinctive chemical, isotopic, and mineralogical characteristics of the formation are pyrrhotite and marcasite, high contents of iron mineral sulfides strikingly enriched in 34S, cyclical trends in sulfur abundance and ??34S values, and long-term evolutionary trends in ??34S values. Analyses that identified and quantified these characteristics include carbonate-free abundance of organic carbon (0.13-47 wt%), total iron (0.31-13 wt%), reactive iron (>70% of total iron), total sulfur (0.02-16 wt%), acid-volatile monosulfide (SAv), disulfide (SDi > 70% of total sulfur), sulfate (SSO4) and organosulfur (SOrg); isotopic composition of separated sulfur phases (??34SDi,Av up to +49???); and mineralogy, morphology and paragenesis of sulfide minerals. Mineralogy, morphology, ??34SDi,Av, and ??34SOrg have a distinctive relation, reflecting variable and unique depositional and early diagenetic conditions in the Green River lakes. When the lakes were brackish, dissimilatory sulfate-reducing bacteria in the sediment produced H2S, which initially reacted with labile iron to form pyrite framboids and more gradually with organic matter to form organosulfur compounds. During a long-lived stage of saline lake water, the amount of sulfate supplied by inflow decreased and alkalinity and pH of lake waters increased substantially. Extensive bacterial sulfate reduction in the water column kept lake waters undersaturated with sulfate minerals. A very high H2S:SO4 ratio developed in stagnant bottom water aided by the high pH that kinetically inhibited iron sulfidization. Progressive removal of H2S by coeval formation of iron sulfides and organosulfur compounds caused the isotopic composition of the entire dissolved sulfur reservoir to evolve to ??34S values much greater than that of inflow sulfate, which is estimated to have

Year-round presence of neonicotinoid insecticides in tributaries to the Great Lakes, USA

USGS Publications Warehouse

Hladik, Michelle; Corsi, Steven; Kolpin, Dana W.; Baldwin, Austin K.; Blackwell, Brett R.; Cavallin, Jenna E.

2018-01-01

To better characterize the transport of neonicotinoid insecticides to the world's largest freshwater ecosystem, monthly samples (October 2015–September 2016) were collected from 10 major tributaries to the Great Lakes, USA. For the monthly tributary samples, neonicotinoids were detected in every month sampled and five of the six target neonicotinoids were detected. At least one neonicotinoid was detected in 74% of the monthly samples with up to three neonicotinoids detected in an individual sample (10% of all samples). The most frequently detected neonicotinoid was imidacloprid (53%), followed by clothianidin (44%), thiamethoxam (22%), acetamiprid (2%), and dinotefuran (1%). Thiacloprid was not detected in any samples. The maximum concentration for an individual neonicotinoid was 230 ng L−1 and the maximum total neonicotinoids in an individual sample was 400 ng L−1. The median detected individual neonicotinoid concentrations ranged from non-detect to 10 ng L−1. The detections of clothianidin and thiamethoxam significantly increased as the percent of cultivated crops in the basins increased (ρ = 0.73, P = .01; ρ = 0.66, P = .04, respectively). In contrast, imidacloprid detections significantly increased as the percent of the urbanization in the basins increased (ρ = 0.66, P = .03). Neonicotinoid concentrations generally increased in spring through summer coinciding with the planting of neonicotinoid-treated seeds and broadcast applications of neonicotinoids. More spatially intensive samples were collected in an agriculturally dominated basin (8 sites along the Maumee River, Ohio) twice during the spring, 2016 planting season to provide further information on neonicotinoid inputs to the Great Lakes. Three neonicotinoids were ubiquitously detected (clothianidin, imidacloprid, thiamethoxam) in all water samples collected within this basin. Maximum individual neonicotinoid concentrations was 330 ng L−1�

Geochemical evolution of groundwater in the Mud Lake area, eastern Idaho, USA

USGS Publications Warehouse

Rattray, Gordon W.

2015-01-01

Groundwater with elevated dissolved-solids concentrations—containing large concentrations of chloride, sodium, sulfate, and calcium—is present in the Mud Lake area of Eastern Idaho. The source of these solutes is unknown; however, an understanding of the geochemical sources and processes controlling their presence in groundwater in the Mud Lake area is needed to better understand the geochemical sources and processes controlling the water quality of groundwater at the Idaho National Laboratory. The geochemical sources and processes controlling the water quality of groundwater in the Mud Lake area were determined by investigating the geology, hydrology, land use, and groundwater geochemistry in the Mud Lake area, proposing sources for solutes, and testing the proposed sources through geochemical modeling with PHREEQC. Modeling indicated that sources of water to the eastern Snake River Plain aquifer were groundwater from the Beaverhead Mountains and the Camas Creek drainage basin; surface water from Medicine Lodge and Camas Creeks, Mud Lake, and irrigation water; and upward flow of geothermal water from beneath the aquifer. Mixing of groundwater with surface water or other groundwater occurred throughout the aquifer. Carbonate reactions, silicate weathering, and dissolution of evaporite minerals and fertilizer explain most of the changes in chemistry in the aquifer. Redox reactions, cation exchange, and evaporation were locally important. The source of large concentrations of chloride, sodium, sulfate, and calcium was evaporite deposits in the unsaturated zone associated with Pleistocene Lake Terreton. Large amounts of chloride, sodium, sulfate, and calcium are added to groundwater from irrigation water infiltrating through lake bed sediments containing evaporite deposits and the resultant dissolution of gypsum, halite, sylvite, and bischofite.

Late Pleistocene Hansel Valley basaltic ash, northern Lake Bonneville, Utah, USA

USGS Publications Warehouse

Miller, D.M.; Oviatt, Charles G.; Nash, B.P.

2008-01-01

The Hansel Valley ash bed lies within 5 cm of the base of deposits of Lake Bonneville (???28 ka) in the vicinity of Great Salt Lake and provides a useful stratigraphic marker for this area of the lake basin. However, it has not been matched to an eruptive edifice, presumably because such an edifice was eroded by waves of Lake Bonneville. We present data for the chemical composition of the tephra and for possible matching lavas and tephras of the region, as well as grain size data for the tephra in an attempt to identify the location of the eruption. Matches with other tephras are negative, but lavas near the coarsest ash deposits match well with the distinctive high values of TiO2 and P2O5 of the ash. Neither chemistry nor grain size data points uniquely to a source area, but an area near the northwest shore of Great Salt Lake and within Curlew Valley is most likely. The Hansel Valley ash is an example of an ash that has no direct numerical date from proximal deposits, despite considerable study, yet nonetheless is useful for stratigraphic studies by virtue of its known stratigraphic position and approximate age. Basaltic tephras commonly are not as widespread as their rhyolitic counterparts, and in some cases apparently are produced by eruptive sources that are short lived and whose edifices are not persistent. ?? 2007 Elsevier Ltd and INQUA.

Sierra Nevada Ecosystem Project

Treesearch

C. I. Millar

1996-01-01

Sierra Nevada Ecosystems. The Sierra Nevada evokes images particular to each individual's experience of the range. These images take on the quality of immutability, and we expect to find the range basically unchanged from one year to the next. The Sierra Nevada, however, including its rocky foundations and the plants and animals that inhabit it, changes...

Small lakes show muted climate change signal in deepwater temperatures

USGS Publications Warehouse

Winslow, Luke A.; Read, Jordan S.; Hansen, Gretchen J. A.; Hanson, Paul C.

2015-01-01

Water temperature observations were collected from 142 lakes across Wisconsin, USA, to examine variation in temperature of lakes exposed to similar regional climate. Whole lake water temperatures increased across the state from 1990 to 2012, with an average trend of 0.042°C yr−1 ± 0.01°C yr−1. In large (>0.5 km2) lakes, the positive temperature trend was similar across all depths. In small lakes (<0.5 km2), the warming trend was restricted to shallow waters, with no significant temperature trend observed in water >0.5 times the maximum lake depth. The differing response of small versus large lakes is potentially a result of wind-sheltering reducing turbulent mixing magnitude in small lakes. These results demonstrate that small lakes respond differently to climate change than large lakes, suggesting that current predictions of impacts to lakes from climate change may require modification.

Surficial Geology of the Floor of Lake Mead (Arizona and Nevada) as Defined by Sidescan-Sonar Imagery, Lake-Floor Topography, and Post-Impoundment Sediment Thickness

USGS Publications Warehouse

Twichell, D.C.; Cross, V.A.

2009-01-01

Sidescan-sonar imagery collected in Lake Mead during 1999-2001, a period of high lake level, has been used to map the surficial geology of the floor of this large reservoir that formed upon completion of the Hoover Dam in 1935. Four surficial geologic units were identified and mapped: rock exposures and alluvial deposits that existed prior to the formation of the lake and thin post-impoundment sediments ( 1 m) deposited since the lake formed. Exposures of rock are most extensive in the narrow, steep-sided sections of the lake, while alluvial deposits are most extensive on the gentle flanks of the broader basin sections of the lake. Post-impoundment sediment is restricted to the floors of the original river valleys that now lie below lake level. These sediments are thickest in the deltas that form at the mouths of the Colorado River and its tributaries, but cover the entire length of the valley floors of the lake. This sediment distribution is consistent with deposition from turbidity currents. Lake level has dropped more than 30 m between collection of the sidescan imagery and publication of this report. During this time, thick delta deposits have been eroded and redistributed to deeper parts of the lake by turbidity currents. While present-day post-impoundment sediment distribution should be similar to what it was in 2001, the thickness may be greater in some of the deeper parts of the lake now.

Productivity, embryo and eggshell characteristics, and contaminants in bald eagles from the Great Lakes, USA, 1986 to 2000

USGS Publications Warehouse

Best, David A.; Elliott, Kyle; Bowerman, William; Shieldcastle, Mark C.; Postupalsky, Sergej; Kubiak, Timothy J.; Tillitt, Donald E.; Elliott, John E.

2010-01-01

Chlorinated hydrocarbon concentrations in eggs of fish-eating birds from contaminated environments such as the Great Lakes of North America tend to be highly intercorrelated, making it difficult to elucidate mechanisms causing reproductive impairment, and to ascribe cause to specific chemicals. An information- theoretic approach was used on data from 197 salvaged bald eagle (Haliaeetus leucocephalus) eggs (159 clutches) that failed to hatch in Michigan and Ohio, USA (1986–2000). Contaminant levels declined over time while eggshell thickness increased, and by 2000 was at pre-1946 levels. The number of occupied territories and productivity increased during 1981 to 2004. For both the entire dataset and a subset of nests along the Great Lakes shoreline, polychlorinated biphenyls (ΣPCBs, fresh wet wt) were generally included in the most parsimonious models (lowest-Akaike's information criterion [AICs]) describing productivity, with significant declines in productivity observed above 26 µg/g ΣPCBs (fresh wet wt). Of 73 eggs with a visible embryo, eight (11%) were abnormal, including three with skewed bills, but they were not associated with known teratogens, including ΣPCBs. Eggs with visible embryos had greater concentrations of all measured contaminants than eggs without visible embryos; the most parsimonious models describing the presence of visible embryos incorporated dieldrin equivalents and dichlorodiphenyldichloroethylene (DDE). There were significant negative correlations between eggshell thickness and all contaminants, with ΣPCBs included in the most parsimonious models. There were, however, no relationships between productivity and eggshell thickness or Ratcliffe's index. The ΣPCBs and DDE were negatively associated with nest success of bald eagles in the Great Lakes watersheds, but the mechanism does not appear to be via shell quality effects, at least at current contaminant levels, while it is not clear what other mechanisms were involved.

Application of digital image processing techniques and information systems to water quality monitoring of Lake Tahoe

NASA Technical Reports Server (NTRS)

Smith, A. Y.; Blackwell, R. J.

1981-01-01

The Tahoe basin occupies over 500 square miles of territory located in a graben straddling the boundary between California and Nevada. Lake Tahoe contains 126 million acre-feet of water. Since the 1950's the basin has experienced an ever increasing demand for land development at the expense of the natural watershed. Discharge of sediment to the lake has greatly increased owing to accelerated human interference, and alterations to the natural drainage patterns are evident in some areas. In connection with an investigation of the utility of a comprehensive system that takes into account the causes as well as the effects of lake eutrophication, it has been attempted to construct an integrated and workable data base, comprised of currently available data sources for the Lake Tahoe region. Attention is given to the image based information system (IBIS), the construction of the Lake Tahoe basin data base, and the application of the IBIS concept to the Lake Tahoe basin.

A 900-Year Diatom and Chrysophyte Record of Spring Mixing and Summer Stratification From Varved Lake Mina, West-Central Minnesota, USA

NASA Astrophysics Data System (ADS)

St. Jacques, J.; Cumming, B. F.; Smol, J. P.

2009-05-01

A high-resolution, independent pollen-inferred paleoclimate record and direct algal seasonality data from the actual time of sediment deposition are used to interpret the high-resolution diatom and chrysophyte record of varved Lake Mina, west-central Minnesota, USA during AD 1116-2002. This direct algal seasonality information was obtained by a new technique of splitting varves into constituent winter-spring and summer lamina, and separately analyzing the siliceous algae in each layer. Analyses of integrated, continuous four-year diatom and chrysophyte samples from a sedimentary sequence show that the time period AD 1116-1478 (i.e. the Atlantic- centered Medieval Climate Anomaly (MCA)) was characterized by periods of vigorous and prolonged spring mixing, suggesting that ice-out occurred early. However, the warm summer temperatures in the MCA, particularly in a massive drought spanning AD 1300-1400, frequently caused the lake to stratify strongly, leading to nutrient depletion. During AD 1478-1870 (i.e. the Atlantic-centered Little Ice Age (LIA)), Lake Mina was characterized by weak spring circulation and increasing nutrient depletion, suggesting late ice-out conditions. Strong summer stratification and/or nutrient depletion in both time periods is shown by the occurrence of the nutrient-poor oligotrophic taxon Cyclotella pseudostelligera. The diatom and chrysophyte assemblages of the period of Euro-American settlement AD 1870-2002 show higher nutrient availability and increased spring mixing intensity, due to forest clearance and increasingly earlier ice-out (documented in regional historical records).

Holocene dune formation at Ash Meadows National Wildlife Area, Nevada, USA

USGS Publications Warehouse

Lancaster, Nicholas; Mahan, Shannon

2012-01-01

Small isolated dune fields in the northern Mojave Desert are important centers of biodiversity and archaeological occupation sites. Currently dunes at Ash Meadows, Nevada, are stabilized by vegetation and are experiencing erosion of their upwind margins, indicating a negative sediment budget. New OSL ages from dunes at Ash Meadows indicate continuous eolian accumulation from 1.5 to 0.8 ka, with further accumulation around 0.2 ka. Prior studies (e.g., Mehringer and Warren, 1976) indicate periods of dune accumulation prior to 3.3 ka; 1.9–1 ka; and after 0.9 ka. These periods of eolian accumulation are largely synchronous with those identified elsewhere in the Mojave Desert. The composition of the Ash Meadows dunes indicates their derivation from regional fluvial sources, most likely during periods when axial washes were active as a result of enhanced winter precipitation.

Examining seasonal variations in microbial community composition and metabolism in Lake Tahoe, Sierra Nevada, California to gain insight into the role of spring freshet and lake mixing on lake microbial ecology and biogeochemistry

NASA Astrophysics Data System (ADS)

Aluwihare, L.

2016-12-01

The 2016 "State of the Lake Report" for Lake Tahoe notes that surface waters of have warmed 15 times faster in the last four years as compared to the long trend. Lake mixing depth has decreased with only 4 instances of full-lake mixing ( 450 m) recorded since 2000, none since 2011, and the shallowest depth of mixing on record, 80 m, was observed in 2015. Snowpack in the region shows a long-term decline, and April snowpack in 2015 was the lowest recorded in nearly 100 years. Lake biomass peaks shortly after mixing occurs, which demonstrates the dependence of lake primary production on this process. Lake mixing also oxygenates deep waters of the lake. Mixing, organic matter production, and vertical gradients in nutrient and oxygen concentrations profoundly impact the depth distribution of microbial communities and metabolisms. Spring melt also brings nutrients into the lake including organic matter; and in other high elevation lake systems it has been shown that streamflow seeds the lake's microbiome. Here we present data from an year long observation of monthly changes in microbial (including phytoplankton) community composition to examine how the seasonally segregated processes of runoff, lake mixing, and surface primary production affect Lake Tahoe's microbial ecology. Members of certain phylogenetic groups showed trends that we are currently exploring in the context of their metabolic capabilities. For example, Chlorobi and Chloroflexi primarily appear in surface waters during deep mixing, consistent with some of them being sensitive to oxygen. Similarly, common but poorly characterized clades of Actinobacteria exhibited negative responses to discharge, while certain clades of Betaproteobacteria exhibited a positive response during and following discharge events at LT. Actinobacteria have been found to be abundant in numerous lake systems suggesting that their metabolic capabilities maybe particularly telling of the dominant species sorting mechanisms at play in

Houston/Galveston, Texas, USA

NASA Image and Video Library

1991-09-18

In this view of Houston/Galveston, Texas, USA (29.5N, 95.5W), heavy spring rains emphasize the several bodies of water in the area. Even though partially cloud covered, the progressive nature of the Houston highway and freeway system can easily be observed in this highly detailed view. To the south, the NASA, Clear Lake area just off of Galveston Bay can easily be seen. In the center, is the downtown business district.

Nevada's Children: Selected Educational and Social Statistics. Nevada and National.

ERIC Educational Resources Information Center

Horner, Mary P., Comp.

This statistical report describes the successes and shortcomings of education in Nevada and compares some statistics concerning education in Nevada to national norms. The report, which provides a comprehensive array of information helpful to policy makers and citizens, is divided into three sections. The first section presents statistics about…

Morphometric and histopathological parameters of gonadal development in adult common carp from contaminated and reference sites in Lake Mead, Nevada

USGS Publications Warehouse

Patino, R.; Goodbred, S.L.; Draugelis-Dale, R.; Barry, C.E.; Scott, Foott J.; Wainscott, M.R.; Gross, T.S.; Covay, K.J.

2003-01-01

This study examined the hypothesis that exposure to sublethal concentrations of contaminants alters the gonadal condition of feral common carp Cyprinus carpio. Adult common carp in Lake Mead, Nevada, were collected from a contaminated site (Las Vegas Bay) that receives municipal and industrial effluent and from a reference site (Overton Arm) with a relatively low level of contamination. Fish were sampled seven times over a 1-year period extending over two separate spawning seasons. Morphometric and histopathological parameters of gonadal and germ cell development were determined. In males, the pattern of seasonal changes in the gonadosomatic index (GSI) was similar between the sites and showed no clear association with site-specific seasonal temperature profiles. However, Las Vegas Bay males had consistently lower GSI values and, on one of the sampling dates, a lower proportion of sperm relative to other germ cell stages (determined histologically). Further, Las Vegas Bay males had a higher incidence of gonadal macrophage aggregates, which are putative tissue biomarkers of contaminant exposure in fishes. In females, seasonal GSI profiles, the frequency of fish with postovulatory follicles (an index of spawning activity), and the timing of new follicle recruitment all showed differences between sites, but these differences generally matched differences in water temperature profile. Also, the peak size-frequency of full-grown follicles did not differ between sites, and estimates of fecundity for the second spawning season indicated that females from the reference site unexpectedly produced a lower number of gametes, Overall, site differences in gonadal condition were observed in carp of both sexes but they seemed to be associated with site differences in contaminant levels only in males. The apparent lack of association between contaminant level and gonadal condition in female carp from mildly mesotrophic Lake Mead may indicate a lack of contaminant effects in

Water-level changes and directions of ground-water flow in the shallow aquifer, Fallon area, Churchill County, Nevada

USGS Publications Warehouse

Seiler, R.L.; Allander, K.K.

1993-01-01

The Truckee-Carson-Pyramid Lake Water Rights Settlement Act of 1990 directed the U.S. Fish and Wildlife Service to acquire water rights for wetland areas in the Carson Desert, Nevada. The public is concerned that htis acquisition of water rights and delivery of the water directly to wildlife areas would result in less recharge to the shallow ground water in the Fallon area and cause domestic wells to go dry. In January 1992, the U.S. Geological Survey, in cooperation with U.S. Fish and Wildlife Service, began a study of the shallow ground-water system in the Fallon area in Churchill County, Nevada. A network of 126 wells in the study area was monitored. Between January and November 1992, water levels in most wells declined, usually less than 2 feet. The maximum measured decline over this period was 2.68 feet in a well near Stillwater Marsh. Between April and July, however, water levels rose in irrigated areas, typically 1 to 2 feet. Newlands Project water deliveries to the study area began soon after the turn of the century. Since then, water levels have risen more than 15 feet across much of the study area. Water lost from unlined irrigtiaon canals caused the stage in Big Soda Lake to rise nearly 60 feet; ground-water levels near the lake have risen 30 to 40 feet. The depth to water in most irrigated areas is now less than 10 feet. The altitude of the water table ranges from 4.025 feet above sea level 11 miles west of Fallon to 3,865 feet in the Stillwater Marsh area. Ground water flows eastward and divides; some flow goes to the northeast toward the Carson Sink and Stillwater areas, and some goes southeastward to Carson Lake.

Watershed vs. within-lake drivers of nitrogen: phosphorus dynamics in shallow lakes.

PubMed

Ginger, Luke J; Zimmer, Kyle D; Herwig, Brian R; Hanson, Mark A; Hobbs, William O; Small, Gaston E; Cotner, James B

2017-10-01

Research on lake eutrophication often identifies variables affecting amounts of phosphorus (P) and nitrogen (N) in lakes, but understanding factors influencing N:P ratios is important given its influence on species composition and toxin production by cyanobacteria. We sampled 80 shallow lakes in Minnesota (USA) for three years to assess effects of watershed size, proportion of watershed as both row crop and natural area, fish biomass, and lake alternative state (turbid vs. clear) on total N : total P (TN : TP), ammonium, total dissolved phosphorus (TDP), and seston stoichiometry. We also examined N:P stoichiometry in 20 additional lakes that shifted states during the study. Last, we assessed the importance of denitrification by measuring denitrification rates in sediment cores from a subset of 34 lakes, and by measuring seston δ 15 N in four additional experimental lakes before and after they were experimentally manipulated from turbid to clear states. Results showed alternative state had the largest influence on overall N:P stoichiometry in these systems, as it had the strongest relationship with TN : TP, seston C:N:P, ammonium, and TDP. Turbid lakes had higher N at given levels of P than clear lakes, with TN and ammonium 2-fold and 1.4-fold higher in turbid lakes, respectively. In lakes that shifted states, TN was 3-fold higher in turbid lakes, while TP was only 2-fold higher, supporting the notion N is more responsive to state shifts than is P. Seston δ 15 N increased after lakes shifted to clear states, suggesting higher denitrification rates may be important for reducing N levels in clear states, and potential denitrification rates in sediment cores were among the highest recorded in the literature. Overall, our results indicate lake state was a primary driver of N:P dynamics in shallow lakes, and lakes in clear states had much lower N at a given level of P relative to turbid lakes, likely due to higher denitrification rates. Shallow lakes are often

Comparing Effects of Lake- and Watershed-Scale Influences on Communities of Aquatic Invertebrates in Shallow Lakes

PubMed Central

Hanson, Mark A.; Herwig, Brian R.; Zimmer, Kyle D.; Fieberg, John; Vaughn, Sean R.; Wright, Robert G.; Younk, Jerry A.

2012-01-01

Constraints on lake communities are complex and are usually studied by using limited combinations of variables derived from measurements within or adjacent to study waters. While informative, results often provide limited insight about magnitude of simultaneous influences operating at multiple scales, such as lake- vs. watershed-scale. To formulate comparisons of such contrasting influences, we explored factors controlling the abundance of predominant aquatic invertebrates in 75 shallow lakes in western Minnesota, USA. Using robust regression techniques, we modeled relative abundance of Amphipoda, small and large cladocera, Corixidae, aquatic Diptera, and an aggregate taxon that combined Ephemeroptera-Trichoptera-Odonata (ETO) in response to lake- and watershed-scale characteristics. Predictor variables included fish and submerged plant abundance, linear distance to the nearest wetland or lake, watershed size, and proportion of the watershed in agricultural production. Among-lake variability in invertebrate abundance was more often explained by lake-scale predictors than by variables based on watershed characteristics. For example, we identified significant associations between fish presence and community type and abundance of small and large cladocera, Amphipoda, Diptera, and ETO. Abundance of Amphipoda, Diptera, and Corixidae were also positively correlated with submerged plant abundance. We observed no associations between lake-watershed variables and abundance of our invertebrate taxa. Broadly, our results seem to indicate preeminence of lake-level influences on aquatic invertebrates in shallow lakes, but historical land-use legacies may mask important relationships. PMID:22970275

Comparing CMIP-3 and CMIP-5 climate projections on flooding estimation of Devils Lake of North Dakota, USA

PubMed Central

2018-01-01

Background Water level fluctuations in endorheic lakes are highly susceptible to even slight changes in climate and land use. Devils Lake (DL) in North Dakota, USA is an endorheic system that has undergone multi-decade flooding driven by changes in regional climate. Flooding mitigation strategies have centered on the release of lake water to a nearby river system through artificial outlets, resulting in legal challenges and environmental concerns related to water quality, downstream flooding, species migration, stakeholder opposition, and transboundary water conflicts between the US and Canada. Despite these drawbacks, running outlets would result in low overspill risks in the next 30 years. Methods In this study we evaluated the efficacy of this outlet-based mitigation strategy under scenarios based on the latest IPCC future climate projections. We used the Coupled Model Intercomparison Project CMIP-5 weather patterns from 17 general circulation models (GCMs) obtained under four representative concentration pathways (RCP) scenarios and downscaled to the DL region. Then, we simulated the changes in lake water levels using the soil and water assessment tool based hydrological model of the watershed. We estimated the probability of future flood risks under those scenarios and compared those with previously estimated overspill risks under the CMIP-3 climate. Results The CMIP-5 ensemble projected a mean annual temperature of 5.78 °C and mean daily precipitation of 1.42 mm/day; both are higher than the existing CMIP-3 future estimates of 4.98 °C and 1.40 mm/day, respectively. The increased precipitation and higher temperature resulted in a significant increase of DL’s overspill risks: 24.4–47.1% without release from outlets and 3.5–14.4% even if the outlets are operated at their combined full 17 m3/s capacity. Discussion The modeled increases in overspill risks indicate a greater frequency of water releases through the artificial outlets. Future risk mitigation

Mammal mortality at Arizona, California, and Nevada gold mines using cyanide extraction

USGS Publications Warehouse

Clark, D.R.; Hothem, R.L.

1991-01-01

Five-hundred nineteen mammals were reported dead at cyanide-extraction gold mines in Arizona [USA], California, and Nevada from 1984 through 1989. Most numerous were rodents (34.9%) and bats (33.7%); 'bat' was the most often reported category among 24 species or species groups. There are an estimated 160 cyanide-extraction gold mines in these three states, and the number is increasing. Ten mammal species listed as endangered, threatened, rare, protected, or species of special concern are known to have cyanide-extraction gold mines within their geographic ranges.

Mechanisms and Magnitude of Cenozoic Crustal Extension in the Vicinity of Lake Mead, Nevada and the Beaver Dam Mountains, Utah: Geochemical, Geochronological,Thermochronological and Geophysical Constraints

NASA Astrophysics Data System (ADS)

Almeida, Rafael V.

The central Basin and Range Province of Nevada and Utah was one of the first areas in which the existence of widespread low-angle normal faults or detachments was first recognized. The magnitude of associated crustal extension is estimated by some to be large, in places increasing original line lengths by as much as a factor of four. However, rock mechanics experiments and seismological data cast doubt on whether these structures slipped at low inclination in the manner generally assumed. In this dissertation, I review the evidence for the presence of detachment faults in the Lake Mead and Beaver Dam Mountains areas and place constraints on the amount of extension that has occurred there since the Miocene. Chapter 1 deals with the source-provenance relationship between Miocene breccias cropping out close to Las Vegas, Nevada and their interpreted source at Gold Butte, currently located 65 km to the east. Geochemical, geochronological and thermochronological data provide support for that long-accepted correlation, though with unexpected mismatches requiring modification of the original hypothesis. In Chapter 2, the same data are used to propose a refinement of the timing of ~1.45 Ga anorogenic magmatism, and the distribution of Proterozoic crustal boundaries. Chapter 3 uses geophysical methods to address the subsurface geometry of faults along the west flank of the Beaver Dam Mountains of southwestern Utah. The data suggest that the range is bounded by steeply inclined normal faults rather than a regional-scale detachment fault. Footwall folding formerly ascribed to Miocene deformation is reinterpreted as an expression of Cretaceous crustal shortening. Fission track data presented in Chapter 4 are consistent with mid-Miocene exhumation adjacent to high-angle normal faults. They also reveal a protracted history dating back to the Pennsylvanian-Permian time, with implications for the interpretation of other basement-cored uplifts in the region. A key finding of this

Calibration of diatom-pH-alkalinity methodology for the interpretation of the sedimentary record in Emerald Lake Integrated watershed study. Final report, 6 May 1985-10 October 1986

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holmes, R.W.

1986-10-10

The present study was designed to establish quantitative relationships between lake air-equilibrated pH, alkalinity, and diatoms occurring in the surface sediments in high-elevation Sierra Nevada Lakes. These relationships provided the necessary information to develop predictive equations relating lake pH to the composition of surface-sediment diatom assemblages in 27 study lakes. Using the Hustedt diatom pH classification system, Index B of Renberg and Hellberg, and multiple linear regression analysis, two equations were developed which predict lake pH from the relative abundance of sediment diatoms occurring in each of four diatom pH groupings.

ORGANIC ACIDITY IN MAINE (U.S.A.) LAKES AND IN HUMEX LAKE SKJERVATJERN (NORWAY)

EPA Science Inventory

Organic acids, a component of dissolved organic carbon can be a major factor in the acidity of many lakes and streams. n order to evaluate the importance of organic acidity, we fractionated (hydrophobic acids and neutrals, hydrophilic acids, bases, and neutrals) and isolated hydr...

The role of shoreland development and commercial cranberry farming in a lake in Wisconsin, USA

USGS Publications Warehouse

Garrison, P.J.; Fitzgerald, S.A.

2005-01-01

Musky Bay in Lac Courte Oreilles, Wisconsin, USA, is currently eutrophic. This large, shallow bay of an oligotrophic lake possesses the densest aquatic plant growth and a floating algal mat. Paleoecological reconstructions encompassing the last 130 years, were based on multiproxy analyses of sediment cores from three coring sites, two within the bay and one in the lake itself. These data were compared to historical records of the construction and expansion of two commercial cranberry bogs and shoreline residential homes to identify temporal and causal relations of eutrophication. The proxies investigated included: minor and trace elements; biogenic silica; and the diatom community. Post-depositional diagenesis of organic carbon, nitrogen, and phosphorus in the upper 30 cm of the core obscured records of historical ambient nutrient concentrations in the bay obviating their usefulness for this purpose. In contrast, calcium, magnesium, and potassium concentration profiles appeared to reflect runoff of soil amendments applied to the cranberry bogs and aerial fertilizer spraying over the eastern bog adjacent to Musky Bay. The increase in aluminum content since about 1930 coincided with the historical trend in shoreland development and construction of the original commercial cranberry farm. The biogenic silica profile recorded a steady increase of nutrients to Musky Bay over the last several decades. Stratigraphic changes in the diatom community indicated that nutrient input began to increase in the 1940s and accelerated in the mid-1990s with the onset of a noxious floating algal mat. The diatom community indicates the bay has possessed a significant macrophyte community for at least the last 200 years, but increased nutrient input was manifested by a change in the composition, and an increase in the density of the epiphytic diatom community. Cranberry farming appeared to be the major source of nutrients because the diatom community changes occurred prior to the

EnergyFit Nevada (formerly known as the Nevada Retrofit Initiative) final report and technical evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carvill, Anna; Bushman, Kate; Ellsworth, Amy

2014-06-17

The EnergyFit Nevada (EFN) Better Buildings Neighborhood Program (BBNP, and referred to in this document as the EFN program) currently encourages Nevada residents to make whole-house energy-efficient improvements by providing rebates, financing, and access to a network of qualified home improvement contractors. The BBNP funding, consisting of 34 Energy Efficiency Conservation Block Grants (EECBG) and seven State Energy Program (SEP) grants, was awarded for a three-year period to the State of Nevada in 2010 and used for initial program design and implementation. By the end of first quarter in 2014, the program had achieved upgrades in 553 homes, with anmore » average energy reduction of 32% per home. Other achievements included: Completed 893 residential energy audits and installed upgrades in 0.05% of all Nevada single-family homes1 Achieved an overall conversation rate of 38.1%2 7,089,089 kWh of modeled energy savings3 Total annual homeowner energy savings of approximately $525,7523 Efficiency upgrades completed on 1,100,484 square feet of homes3 $139,992 granted in loans to homeowners for energy-efficiency upgrades 29,285 hours of labor and $3,864,272 worth of work conducted by Nevada auditors and contractors4 40 contractors trained in Nevada 37 contractors with Building Performance Institute (BPI) certification in Nevada 19 contractors actively participating in the EFN program in Nevada 1 Calculated using 2012 U.S. Census data reporting 1,182,870 homes in Nevada. 2 Conversion rate through March 31, 2014, for all Nevada Retrofit Initiative (NRI)-funded projects, calculated using the EFN tracking database. 3 OptiMiser energy modeling, based on current utility rates. 4 This is the sum of $3,596,561 in retrofit invoice value and $247,711 in audit invoice value.« less

Geomorphic constraints on the evolution of the Kern Gorge, southern Sierra Nevada, California.

NASA Astrophysics Data System (ADS)

Foreshee, B. C.; Krugh, W. C.

2016-12-01

The Kern River is uniquely positioned to respond to tectonic activity that occurs within the southern Sierra Nevada and southern San Joaquin Basin, CA. The North and South forks of the upper Kern River (above Lake Isabella) are fed by tributaries that primarily drain the high-elevation low-relief landscape of the Kern Plateau. These south flowing trunk streams switch to a dominantly southwest flow direction at the Lake Isabella Reservoir and South Lake Valley respectively. Downstream from Lake Isabella, the Kern River steepens as it flows through the Kern Gorge and then crosses the Kern Arch region of the San Joaquin Basin. Clark et al., (2005) used low-temperature thermochronometry and trunk and tributary channel profiles from the upper Kern River catchment to identify two periods of rapid incision that occurred from 32.0 to 3.5 Ma and from 3.5 Ma to present. Cecil et al., (2014) used low-temperature thermochronometry from well cores of Oligocene-Miocene sandstones to investigate the time-temperature history of the Kern Arch and identified a period of subsidence and sedimentation between 6.0 and 1.0 Ma that was immediately followed by rapid exhumation. They attributed these results to the northwest migration of a delaminating lithospheric root. In this study we examine the erosional and depositional history within the Kern Gorge to investigate the response of the Kern River to Pliocene-Pleistocene tectonic activity within the Kern Arch and southern Sierra Nevada. Quantitative stream profile analyses and geomorphic mapping within the Kern Gorge are being conducted using USGS 10m DEM data, satellite and aerial imagery, and field based observations and measurements. Reconnaissance mapping efforts have so far identified several strath terraces, alluvial fill terraces, colluvial deposits, and multiple debris flow and landslide deposits that have been incised by the Kern River and are now preserved above the active channel. These geomorphic landforms are currently being

Overstory and understory dynamics in a ponderosa pine plantation vary with stand density in the Sierra Nevada: 40-year results

Treesearch

Jianwei Zhang; William W. Oliver; Martin W. Ritchie; Donald L. Neal

2013-01-01

We periodically measured overstory ponderosa pine (Pinus ponderosa) growth and understory cover and abundance in a long-term study on the west slope of the Sierra Nevada, California, USA. The study was established in 1969 in a 20-year-old plantation, thinned to basal areas of 9, 16, 23, 30, and 37 m2 ha-1...

Concentrations and distribution of manmade organic compounds in the Lake Tahoe Basin, Nevada and California, 1997-99

USGS Publications Warehouse

Lico, Michael S.; Pennington, Nyle

1999-01-01

The U.S. Geological Survey, in cooperation with the Tahoe Regional Planning Agency and the Lahontan Regional Water-Quality Control Board, sampled Lake Tahoe, major tributary streams to Lake Tahoe, and several other lakes in the Lake Tahoe Basin for manmade organic compounds during 1997-99. Gasoline components were found in all samples collected from Lake Tahoe during the summer boating season. Methyl tert-butyl ether (MTBE), benzene, toluene, ethylbenzene, and xylenes (BTEX) were the commonly detected compounds in these samples. Most samples from tributary streams and lakes with no motorized boating had no detectable concentrations of gasoline components. Motorized boating activity appears to be directly linked in space and time to the occurrence of these gasoline components. Other sources of gasoline components to Lake Tahoe, such as the atmosphere, surface runoff, and subsurface flow, are minor compared to the input by motorized boating. Water sampled from Lake Tahoe during mid-winter, when motorized boating activity is low, had no MTBE and only one sample had any detectable BTEX compounds. Soluble pesticides rarely were detected in water samples from the Lake Tahoe Basin. The only detectable concentrations of these compounds were in samples from Blackwood and Taylor Creeks collected during spring runoff. Concentrations found in these samples were low, in the 1 to 4 nanograms per liter range. Organochlorine compounds were detected in samples collected from semipermeable membrane devices (SPMD's) collected from Lake Tahoe, tributary streams, and Upper Angora Lake. In Lake Tahoe, SPMD samples collected offshore from urbanized areas contained the largest number and highest concentrations of organochlorine compounds. The most commonly detected organochlorine compounds were cis- and trans-chlordane, p, p'-DDE, and hexachlorobenzene. In tributary streams, SPMD samples collected during spring runoff generally had higher combined concentrations of organochlorine

The Younger Dryas phase of Great Salt Lake, Utah, USA

USGS Publications Warehouse

Oviatt, Charles G.; Miller, D.M.; McGeehin, J.P.; Zachary, C.; Mahan, S.

2005-01-01

Field investigations at the Public Shooting Grounds (a wildlife-management area on the northeastern shore of Great Salt Lake) and radiocarbon dating show that the Great Salt Lake rose to the Gilbert shoreline sometime between 12.9 and 11.2 cal ka. We interpret a ripple-laminated sand unit exposed at the Public Shooting Grounds, and dated to this time interval, as the nearshore sediments of Great Salt Lake deposited during the formation of the Gilbert shoreline. The ripple-laminated sand is overlain by channel-fill deposits that overlap in age (11.9-11.2 cal ka) with the sand, and by wetland deposits (11.1 to 10.5 cal ka). Consistent accelerator mass spectrometry radiocarbon ages were obtained from samples of plant fragments, including those of emergent aquatic plants, but mollusk shells from spring and marsh deposits yielded anomalously old ages, probably because of a variable radiocarbon reservoir effect. The Bonneville basin was effectively wet during at least part of the Younger Dryas global-cooling interval, however, conflicting results from some Great Basin locations and proxy records indicate that the regional effects of Younger Dryas cooling are still not well understood. ?? 2005 Elsevier B.V. All rights reserved.

Inputs and internal cycling of nitrogen to a causeway influenced, hypersaline lake, Great Salt Lake, Utah, USA

USGS Publications Warehouse

Naftz, David L.

2017-01-01

Nitrogen inputs to Great Salt Lake (GSL), located in the western USA, were quantified relative to the resident nitrogen mass in order to better determine numeric nutrient criteria that may be considered at some point in the future. Total dissolved nitrogen inputs from four surface-water sources entering GSL were modeled during the 5-year study period (2010–2014) and ranged from 1.90 × 106 to 5.56 × 106 kg/year. The railroad causeway breach was a significant conduit for the export of dissolved nitrogen from Gilbert to Gunnison Bay, and in 2011 and 2012, net losses of total nitrogen mass from Gilbert Bay via the Causeway breach were 9.59 × 105 and 1.51 × 106 kg. Atmospheric deposition (wet + dry) was a significant source of nitrogen to Gilbert Bay, exceeding the dissolved nitrogen load contributed via the Farmington Bay causeway surface-water input by >100,000 kg during 2 years of the study. Closure of two railroad causeway culverts in 2012 and 2013 likely initiated a decreasing trend in the volume of the higher density Deep Brine Layer and associated declines in total dissolved nitrogen mass contained in this layer. The large dissolved nitrogen pool in Gilbert Bay relative to the amount of nitrogen contributed by surface-water inflow sources is consistent with the terminal nature of GSL and the predominance of internal nutrient cycling. The opening of the new railroad causeway breach in 2016 will likely facilitate more efficient bidirectional flow between Gilbert and Gunnison Bays, resulting in potentially substantial changes in nutrient pools within GSL.

Grand Canyon, Lake Powell, and Lake Mead

NASA Technical Reports Server (NTRS)

2002-01-01

A snowfall in the American West provides contrast to the landscape's muted earth tones and indicates changes in topography and elevation across (clockwise from top left) Nevada, Utah, Colorado, New Mexico, Arizona, and California. In Utah, the southern ranges of the Wasatch Mountains are covered in snow, and the Colorado River etches a dark ribbon across the red rock of the Colorado Plateau. In the center of the image is the reservoir created by the Glen Canyon Dam. To the east are the gray-colored slopes of Navaho Mountain, and to the southeast, dusted with snow is the region called Black Mesa. Southwest of Glen Canyon, the Colorado enters the Grand Canyon, which cuts westward through Arizona. At a deep bend in the river, the higher elevations of the Keibab Plateau have held onto snow. At the end of the Grand Canyon lies another large reservoir, Lake Mead, which is formed by the Hoover Dam. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

Aqueous Geochemistry of Lake Tuscaloosa, West-Central Alabama, USA: Drought Response

NASA Astrophysics Data System (ADS)

Creech, L., Jr.; Donahoe, R. J.

2008-12-01

Lake Tuscaloosa was created in 1969 by the impoundment of the North River near Northport and Tuscaloosa, AL. The reservoir is 25 miles long with a capacity of 123,000 acre-feet, a surface area of 5,885 acres, and an estimated safe yield of 200 M gal/d. It is the receiving water body of a 432 square mile watershed. This project studies the aqueous geochemistry of surface waters using samples representative of different seasonal conditions and land cover. Of the 21 sample locations in this study, three are located on tributaries, four transect the axis of the lake, and the rest are divided among semi-restricted coves representing forested and residential land cover. Sample chemistry is quantified for major, minor, and trace cations, anions, and nutrients, total dissolved nitrogen, DOC, and ALK. The current study presents data collected from the lake and its tributaries during recent severe drought conditions impacting much of the southeastern United States. These data are compared with data from an identical study conducted five years ago during a more normal water year. For each sampling year, four seasonal sampling events were conducted. Both intra- and inter-annual results are reported. Historical USGS data for seven locations sampled since 1986 on a semi-annual basis illustrate a general increase in TDS and nutrients since the lake's creation. Some USGS sample locations coincide with those of the current study. Recently collected data agrees well with recent USGS data for the same locations. It is likely that trends observed in this study are related to anthropogenic effects along the lake shore, as evidenced by the geochemical differences between residential and forested coves. Long-term trends observed in historical data are likely the result of land use in the watershed related to mining, agriculture, and residential development. It is also observed that lower flow conditions are associated with increased solute concentrations, indicating that dilution by

Historical sediment mercury deposition trends for South Dakota lakes

USGS Publications Warehouse

Squillace, Maria K.; Sieverding, Heidi L.; Betemariam, Hailemelekot H.; Urban, Noel R.; Penn, Michael R.; DeSutter, Thomas M.; Chipps, Steven R.; Stone, James J.

2018-01-01

PurposeSelect South Dakota, USA water bodies, including both natural lakes and man-made impoundments, were sampled and analyzed to assess mercury (Hg) dynamics and historical patterns of total Hg deposition.Materials and methodsSediment cores were collected from seven South Dakota lakes. Mercury concentrations and flux profiles were determined using lead (210Pb) dating and sedimentation rates.Results and discussionMost upper lake sediments contained variable heavy metal concentrations, but became more consistent with depth and age. Five of the seven lakes exhibited Hg accumulation fluxes that peaked between 1920 and 1960, while the remaining two lakes exhibited recent (1995–2009) Hg flux spikes. Historical sediment accumulation rates and Hg flux profiles demonstrate similar peak and stabilized values. Mercury in the sampled South Dakota lakes appears to emanate from watershed transport due to erosion from agricultural land use common to the Northern Great Plains.ConclusionsFor sampled South Dakota lakes, watershed inputs are more significant sources of Hg than atmospheric deposition.

Heavy metal distribution and water quality characterization of water bodies in Louisiana's Lake Pontchartrain Basin, USA.

PubMed

Zhang, Zengqiang; Wang, Jim J; Ali, Amjad; DeLaune, Ronald D

2016-11-01

The seasonal variation in physico-chemical properties, anions, and the heavy metal (Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn) concentration was evaluated in water from nine different rivers in Lake Pontchartrain Basin, Louisiana, USA. The water quality parameters were compared with toxicity reference values (TRV), US Environmental Protection Agency (USEPA) drinking/aquatic life protection, and WHO standards. Among physico-chemical properties, pH, DO, and turbidity were high during spring, while, EC, temperature, and DOC were high during summer and vice versa. The anion study revealed that the concentrations of F - , Cl - , and NO 3 - were higher during summer and Br - and SO 4 - were higher during spring. Our research findings showed anion concentration decreased in the order of Cl -  > SO 4 -  > NO 3 -  > Br -  > F - , in accordance with the global mean anion concentration. The dissolved heavy metals (Cd, Co, Cr, Cu, Mn, Ni, Pb) except Zn were higher during spring than summer. None of the rivers showed any Cd pollution for both seasons. Co showed higher concentrations in Amite River, Mississippi River, Industrial Canal, and Lacombe Bayou during summer. The Cr concentration was higher than WHO drinking water standards, implicating water unsuitability for drinking purposes in all the rivers associated with the Lake Pontchartrain Basin. Cu showed no pollution risk for the study area. Mn and Co were similar to concentration in Lacombe Bayou, Liberty Bayou, Blind River, and Industrial Canal. Mn levels were greater than WHO standards for the Tickfaw River, Tangipahoa River, and Blind River in both seasons. Blind River, Tangipahoa River, Tickfaw River, and Amite River will require more monitoring for determining possible Mn pollution. Ni content in river water during both seasons showed low pollution risk. Liberty Bayou and Industrial Canal concentrations were closer to the WHO regulatory standards, indicating possible risk of Pb pollution in these water bodies. The Zn

Mobility of 137Cs in freshwater lakes: A mass balance and diffusion study of Lake St. Clair, Southeast Michigan, USA

NASA Astrophysics Data System (ADS)

Wang, Jinlong; Baskaran, Mark; Niedermiller, John

2017-12-01

Cesium-137 is one of the most widely utilized anthropogenic radionuclides, both as a tracer and chronometer in the environment. Its application as an effective chronometer requires a thorough understanding of its geochemical behavior in aqueous systems. In this study, we collected and analyzed a suite of time-series water samples over a period of 8 months (April - November 2015), for particulate and dissolved 137Cs activities from a watershed in southeast Michigan, USA, using Cu2Fe(CN)6-coated cartridges developed to pre-concentrate dissolved 137Cs. We also conducted a series of laboratory experiments with the natural freshwater sediment samples and water with different chemical composition. There were seasonal variations of both particulate and dissolved 137Cs activities in the watersheds of Lake St. Clair. The distribution coefficients of 137Cs determined over a period of 8 months varied between 0.14 × 105 and 6.1 × 105 mL g-1 (mean: 2.9 × 105 mL g-1). The annual input and export flux of total 137Cs activity via rivers into and out of Lake St. Clair were calculated to be 3.6 × 1010 Bq and 1.6 × 1010 Bq, respectively. The amount of 137Cs derived by diffusion from interstitial pore water to the water column was estimated to be 0.30 × 1010 Bq (8.3% of the total input flux) which is similar to the percentage of 137Cs desorption (13%-20%) from sediment placed in oxic soft water system over a period of 30-106 days. For the same concentrations of NH4+, Mn2+, K+, Mg2+, Ca2+, Na+ and Sr2+ in a distilled water, our lab work showed that the sediment-sorbed 137Cs is displaced by ions in the order NH4+ > Mn2+ > K+ > Mg2+ ≈ Ca2+ > Na+ > Sr2+. In laboratory studies, 137Cs sorbed onto sediment was found to be less mobile in oxic soft water (Kd: 2.0 × 103 mL g-1) and more mobile in anoxic soft water (Kd: 0.2 × 103 mL g-1). In a hard water system, however, there is no significant difference in Kd values for both oxic and anoxic conditions. The sequence of Kd values is

The Effect of Local Lacustrine Conditions on the Expression of Regional Holocene Climate in the Ruby Mountains, Nevada, USA

NASA Astrophysics Data System (ADS)

Starratt, S.; Kusler, J. E.; Addison, J. A.; Wahl, D.

2013-12-01

Climate of the north-central Great Basin currently exhibits a bimodal precipitation pattern, dominated by winter (NDJF) precipitation from the eastern Pacific Ocean, augmented by late spring (MJ) convectional precipitation. Reconstruction of past moisture variability has proven difficult due to limited paleoclimate records in this region and the effect of lake-specific and local watershed characteristics. In order to better understand the Holocene climate record a series of cores were collected in Favre Lake (2902 masl, 8 ha, 12 m deep) using a modified Livingstone piston corer. The presence of the Mazama ash in the basal sediment (~4 m below the sediment/water interface) indicates the record extends to ~7700 cal yr B.P. The pollen record is dominated by Pinus and Artemisia, followed by subordinate levels of Poaceae, Asteraceae, Amaranthaceae, and Sarcobatus. Small fragilarioid diatoms (Pseudostaurosira, Staurosira, and Staurosirella) comprise as much as 80% of the assemblage. The remainder of the assemblage is dominated by benthic taxa. Planktonic species account for about 10% of the assemblage. Biogenic silica values vary between 20 and 30 wt %. These proxies suggest that the lake was small between 7,700 and 5,500 cal yr BP; for most of the remainder of the record, the lake covered a shallow (~1 m deep) shelf, resulting in the dominance of small fragilarioid diatoms. Planktonic species increase in abundance in the last 200 years, indicating the establishment of modern conditions. In order to evaluate the role of local conditions on the climate record, surface sediments were collected from tarns in the northern Ruby Mountains (Lamoille Lake, 2976 masl, 6 ha; Upper Dollar Lake, 2942 masl, ~1 ha, 2 m deep; Lower Dollar Lake, 2937 masl, ~1 ha, 2 m deep; Liberty Lake, 3064 masl, 9 ha, 33 m deep; Castle Lake, 2980 masl, 6 ha, 4.6 m deep; Favre Lake), and East Humboldt Range (Angel Lake, 2553 masl, 5 ha, 9 m deep). Slope aspects above the lakes are north (Lamoille

Late Cenozoic lacustrine and climatic environments at Tule Lake, northern Great Basin, USA

USGS Publications Warehouse

Platt, Bradbury J.

1992-01-01

Cores of lake sediment to a depth of 334 m in the town of Tulelake, Siskiyou County, northern California, document the late Cenozoic paleolimnologic and paleoclimatic history of the northwestern edge of the Great Basin. The cores have been dated by radiometric, tephrochronologic and paleomagnetic analyses. Lacustrine diatoms are abundant throughout the record and document a nearly continuous paleolimnologic history of the Tule Lake basin for the last 3 Myr. During most of this time, this basin (Tule Lake) was a relatively deep, extensive lake. Except for a drier (and cooler?) interval recorded by Fragilaria species about 2.4 Ma, the Pliocene is characterized by a dominance of planktonic Aulacoseira solida implying a warm monomictic lake under a climatic regime of low seasonality. Much of the Pleistocene is dominated by Stephanodiscus and Fragilaria species suggesting a cooler, often drier, and highly variable climate. Benthic diatoms typical of alkaline-enriched saline waters commonly appear after 1.0 Ma, and tephrochronology indicates slow deposition and possible hiatuses between about 0.6 and 0.2 Ma. The chronology of even-numbered oxygen isotope stages approximately matches fluctuations in the abundance of Fragilaria since 800 ka indicating that glacial periods were expressed as drier environments at Tule Lake. Glacial and interglacial environments since 150 ka were distinct from, and more variable than, those occurring earlier. The last full glacial period was very dry, but shortly thereafter Tule Lake became a deep, cool lacustrine system indicating a substantial increase in precipitation. Aulacoseira ambigua characterized the latest glacial and Holocene record of Tule Lake. Its distribution indicates that warmer and wetter climates began about 15 ka in this part of the Great Basin. Diatom concentration fluctuates at 41 000 year intervals between 3.0 and 2.5 Ma and at approximately 100 000 year intervals after 1.0 Ma. In the late Pliocene and early Pleistocene

Floc Size and Settling Velocity Observations From Three Contrastingly Different Natural Environments in the USA

NASA Astrophysics Data System (ADS)

Manning, Andrew; Schoellhamer, David; Mehta, Ashish; Nover, Daniel; Schladow, Geoffrey

2010-05-01

that is the building block of higher order fractal structures. Bioflocculation is deemed extremely important in freshwater environments such as lakes. The Lake Apopka macroflocs (D > 160 μm) encompassed 92% of the floc mass, and demonstrating a Wsmacro of 1.7 mm.s-1 (twice as fast as the Wsmicro), this translated into the macroflocs contributing 96.4% of the total mass settling flux (1.5 g.m-2s-1). Lake Tahoe, which crosses California and Nevada, was the final study location. With a maximum depth of 501 m, it is the second deepest freshwater lake in the USA. However it significantly less turbid than Lake Apopka, with SSC rarely exceeding 10 mg.l-1 during the floc surveys. At depths of both 5 m and 450 m, the SSC was 9.6 and 3 mg.l-1, respectively. Flocs at both depths exhibited Ws of 2-5 mm.s-1. Whereas at a depth of 35 m (Fig. 3c), the SCC was 6.8 mg.l-1 and the flocs fell comparatively slowly (Ws of 0.03-2.4 mm s-1) which suggest that the floc population at 35 m will have a long residence time in the water column, thus impairing long term light penetration. Interestingly, the MSF at 450 m was 10.8 mg.m-2s-1, which was double the flux measured at 35 m, even though the deep water was only half as turbid. This comparison indicates that the size and settling velocity of individual flocs can be measured simultaneously with the video INSSEV_LF instrument within SSC of several g.l-1. This floc data is of great importance for accurate numerical sediment transport model calibration in estuaries (e.g. San Francisco Bay), whilst also equally valuable for addressing environmental problems (e.g. water quality issues) in freshwater environments such as Lake Tahoe and Lake Apopka.

The Lake Forest Tuff Ring, Lake Tahoe, CA: Age and Geochemistry of a Post-arc Phreatomagmatic Eruption

NASA Astrophysics Data System (ADS)

Cousens, B. L.; Henry, C. D.; Pauly, B. D.

2007-12-01

The Lake Tahoe region of the northern Sierra Nevada consists of Mesozoic plutonic rocks blanketed by Mio- Pliocene arc volcanic rocks and locally overlain by < 2.5 Ma post-arc lavas. Several volcanic features along the Lake Tahoe shoreline indicate that magmas commonly erupted into shallow regions of the lake during the last 2.5 Ma, including the Eagle Rock vent (Kortemeier and Schweickert 2007), Tahoe City pillow lavas and palagonite layers, and the Lake Forest tuff ring (Sylvester et al., 2007). Here we report on the age and composition of the rocks at Lake Forest, aiming to identify the source of the volcanic rocks compared to arc and post-arc lavas in the area. The low-relief Lake Forest tuff ring, located on the lakeshore west of Dollar Point, consists of radially outward-dipping layers composed primarily of loosely-cemented angular, microvesicular lava fragments with minor basaltic bombs and a scoria pile at the east end of the exposed ring. Most fragments are poorly phyric, and two samples are andesites similar to post-arc lavas sampled at higher elevations. The bombs are vesicular, poorly olivine/plagioclase-phyric basaltic andesites with chilled margins and glassy matrices. Scoria in the scoria pile, which we tentatively interpret as a slump, are similar texturally to the bombs but are more silica-rich. Chemically, the fragments, bombs and scoria are more primitive (higher Mg number) than local post-arc and arc lavas, and have trace element ratios and normalized incompatible element patterns similar to, but not identical to, local post-arc lava flows. Thus the Lake Forest tuff ring was the product of a shoreline eruptive event and did not form from lavas flowing downslope into the water. The fragments, bombs and scoria each have different radiogenic isotopic compositions and incompatible element ratios, indicating that primary magma compositions varied during the eruption(s) that produced the tuff ring. Our ongoing geochronological analyses will help

Nevada's Children, 1996. Selected Educational and Social Statistics--Nevada and National.

ERIC Educational Resources Information Center

Horner, Mary P., Comp.

This report presents selected 1996 educational and social statistics that provide information about the status of children in Nevada. State statistics are in some cases compared to national statistics. The first part presents facts about education in Nevada with regard to student characteristics, enrollment, racial and ethnic populations, high…

Glacial Lake Musselshell: Late Wisconsin slackwater on the Laurentide ice margin in central Montana, USA

USGS Publications Warehouse

Davis, N.K.; Locke, W. W.; Pierce, K.L.; Finkel, R.C.

2006-01-01

Cosmogenic surface exposure ages of glacial boulders deposited in ice-marginal Lake Musselshell suggest that the lake existed between 20 and 11.5 ka during the Late Wisconsin glacial stage (MIS 2), rather than during the Late Illinoian stage (MIS 6) as traditionally thought. The altitude of the highest ice-rafted boulders and the lowest passes on the modern divide indicate that glacial lake water in the Musselshell River basin reached at least 920-930 m above sea level and generally remained below 940 m. Exposures of rhythmically bedded silt and fine sand indicate that Lake Musselshell is best described as a slackwater system, in which the ice-dammed Missouri and Musselshell Rivers rose and fell progressively throughout the existence of the lake rather than establishing a lake surface with a stable elevation. The absence of varves, deltas and shorelines also implies an unstable lake. The changing volume of the lake implies that the Laurentide ice sheet was not stable at its southernmost position in central Montana. A continuous sequence of alternating slackwater lake sediment and lacustrine sheetflood deposits indicates that at least three advances of the Laurentide ice sheet occurred in central Montana between 20 and 11.5 ka. Between each advance, it appears that Lake Musselshell drained to the north and formed two outlet channels that are now occupied by extremely underfit streams. A third outlet formed when the water in Lake Musselshell fully breached the Larb Hills, resulting in the final drainage of the lake. The channel through the Larb Hills is now occupied by the Missouri River, implying that the present Missouri River channel east of the Musselshell River confluence was not created until the Late Wisconsin, possibly as late as 11.5 ka. ?? 2005 Elsevier B.V. All rights reserved.

Diet dynamics of the adult piscivorous fish community in Spirit Lake, Iowa, USA 1995-1997

USGS Publications Warehouse

Liao, H.; Pierce, C.L.; Larscheid, J.G.

2002-01-01

Diets of adults of six important piscivorous fish species, black crappie Pomoxis nigromaculatus, largemouth bass Micropterus salmoides, northern pike Esox lucius, smallmouth bass Micropterus dolomieui, walleye Stizostedion vitreum, and yellow perch Perca flavescens were quantified in Spirit Lake, Iowa, USA from May to October in 1995-1997. Forty-one prey taxa were found in the diets of these species, including 19 species of fish. The most important prey taxa overall were yellow perch, amphipods and dipterans. Diets of northern pike and walleye were dominated by yellow perch. Largemouth bass diets included large percentages of both yellow perch and black bullhead Ameiurus melas. Smallmouth bass diets included large percentages of both yellow perch and crayfish. Black crappie and yellow perch diets were dominated by invertebrates, primarily amphipods and dipterans. There were pronounced differences in diets among species, among size classes within species and over time. Most of the dominant prey taxa we documented in the diets of piscivorous species were in accordance with previous studies, but a few deviated significantly from expectations. Many of the temporal diet changes were asynchronous among piscivorous species and size classes, suggesting different responses to common prey resources over time.

A Serosurvey of Greater Sage-Grouse ( Centrocercus urophasianus ) in Nevada, USA.

PubMed

Sinai, Nancy L; Coates, Peter S; Andrle, Katelyn M; Jefferis, Chad; Sentíes-Cué, C Gabriel; Pitesky, Maurice E

2017-01-01

To better understand the potential avian diseases in Greater Sage-grouse ( Centrocercus urophasianus ) in the Great Basin in Nevada, US, we collected 31 blood samples March-April 2014 and tested for antibodies to eight viruses and two bacteria. Specifically, sera were tested for antibodies to avian leukosis virus type A, B, and J (ALV-A, ALV-B, and ALV-J, respectively), infectious bursal disease virus, infectious bronchitis virus, reticuloendothelial virus, avian influenza virus (AIV), West Nile virus, Pasteurella multocida (PM), and Salmonella enterica serovar Pullorum. Serum antibodies against ALV-A and -B (1/31, 3%), ALV-J (5/31, 16%), PM (1/31, 3%), and AIV (2/31, 6%) were detected by enzyme-linked immunosorbent assay (ELISA). While ELISA tests used have only been validated in domestic poultry, the serologic data should be used as a potential indicator of the range of bacterial and viral infectious agents that can infect the Greater Sage-grouse.

A serosurvey of Greater Sage-grouse (Centrocercus urophasianus) in Nevada, USA

USGS Publications Warehouse

Sinai, Nancy L; Coates, Peter S.; Andrle, Katelyn M.; Jefferis, Chad; Sentíes–Cué, C. Gabriel; Pitesky, Maurice E.

2017-01-01

To better understand the potential avian diseases in Greater Sage-grouse (Centrocercus urophasianus) in the Great Basin in Nevada, we collected 31 blood samples March–April 2014 and tested for antibodies to eight viruses and two bacteria. Specifically, sera were tested for antibodies to avian leukosis virus type A, B, and J (ALV-A, ALV-B, and ALV-J, respectively), infectious bursal disease virus, infectious bronchitis virus, reticuloendothelial virus, avian influenza virus (AIV), West Nile virus, Pasteurella multocida (PM), and Salmonella enterica serovar Pullorum. Serum antibodies against ALV-A and -B (1/31, 3%), ALV-J (5/31, 16%), PM (1/31, 3%), and AIV (2/31, 6%) were detected by enzyme-linked immunosorbent assay (ELISA). While ELISA tests used have only been validated in domestic poultry, the serologic data should be used as a potential indicator of the range of bacterial and viral infectious agents that can infect the Greater Sage-grouse.

Environmental geochemistry of abandoned mercury mines in West-Central Nevada, USA

USGS Publications Warehouse

Gray, J.E.; Crock, J.G.; Fey, D.L.

2002-01-01

The Humboldt River is a closed basin and is the longest river in Nevada. Numerous abandoned Hg mines are located within the basin, and because Hg is a toxic heavy metal, the potential transport of Hg from these mines into surrounding ecosystems, including the Humboldt River, is of environmental concern Samples of ore, sediment, water, calcines (roasted ore), and leachates of the calcines were analyzed for Hg and other heavy metals to evaluate geochemical dispersion from the mines. Cinnabar-bearing ore samples collected from the mines contain highly elevated Hg concentrations, up to 6.9 %, whereas calcines collected from the mines contain up to 2000 mg Hg/kg. Stream-sediment samples collected within 1 km of the mines contain as much as 170 mg Hg/kg, but those collected distal from the mines (> 5 km) contain 8 km from the Humboldt River, and Hg is transported and diluted through a large volume of pediment before it reaches the Humboldt River. ?? 2002 Elsevier Science Ltd. All rights reserved.

Fire decreases arthropod abundance but increases diversity: early and late season prescribed fire effects in a Sierra Nevada mixed-conifer forest

Treesearch

Scott M. Ferrenberg; Dylan W. Schwilk; Eric E. Knapp; Eric Groth; Jon E. Keeley

2006-01-01

Prior to fire suppression in the 20th century, the mixed-conifer forests of the Sierra Nevada, California, U.S.A., historically burned in frequent fires that typically occurred during the late summer and early fall. Fire managers have been attempting to restore natural ecosystem processes through prescription burning, and have often favored burning during the fall in...

Clean Air Act Permitting in Nevada

EPA Pesticide Factsheets

Information on Clean Air Act permitting in Nevada in Nevada and EPA's oversight. Clean Air Act permitting in Nevada is the shared responsibility of one state and two local agencies, along with EPA Region 9.

Tales from Two Cores: Bayesian Re-Analyses of the Summit Lake and Blue Lakes Pollen Cores

NASA Astrophysics Data System (ADS)

Hall, M.

2016-12-01

Pollen cores from Summit Lake and Blue Lakes in Humboldt Co., Nevada provide palaeoclimatic information for the last 2000 yearsin the NW Great Basin. Summit Lake is in the northern Black Rock Range (41.5 N -119.1 W) and is at an elevation of 1780 m. The Blue Lakes sit at an elevation of 2434 m in the southern Pine Forest Range (41.6 N -118.6 W). The distance between the two lakes is 33.5 km. The cores were originally taken to reconstruct the fire history in the NW Great Basin. In this study, stochastic climate histories are created using a Bayesian methodology as implemented in the Bclim program. This Bayesian approach takes: 1) a multivariate approach based on modern pollen analogs, 2) accounts for the non-linear and non-Gaussian relationship between the climate and the pollen proxy, and 3) accounts for the uncertainties in the radiocarbon record and climate histories. For both cores, the following climatic variables are reported for the last 2 kya: Mean Temperature of the Coldest month (MTCO), Growing Degree Days above 5 Centigrade (GDD5), the ratio of Actual to Potential Evapotranspiration (AET/PET). Because it was sequentially sampled,the Artemesia/Chenopodiaceae ratio (A/C), an indicator of wetness, and the Grasses/Shrubs (G/S) ratio, an indicator of thevegetation communities, is calculated for each section of the Summit Lake core. Bayesian changepoint analyses of the Summit Lake core indicates that there is no significant difference in the mean or variance of the A/C ratio for the last 2 kya cal BP, but there is a significant decrease in G/S ratio dating to circa 700 ya cal BP. At Summit Lake, a statistically significant decrease in the GDD5 occurs at 1.4-1.5 kya cal BP, and a significant increase in the GDD5 occurs for the last 200 ya cal BP. The GDD5 and MTCO for Blue Lakes has a significant increase at 600 ya cal BP, and afterwards decreases in the next century. The regional archaeological record will be discussed in light of these changes.

The eastern front of the Sierra Nevada; prone to earthquakes and volcanic eruption

USGS Publications Warehouse

Rinehart, C.D.; Smith, W.C.

1981-01-01

On Sunday morning, May 25, 1980, the weather at Mammoth Lakes, Calif., was sunny and brisk. Suddenly, just before 9:33 a.m, the world became a jarring, lurching, unstable place. Along the front of the Sierra Nevada, the muffled thunder of rockfalls and avalanches prolonged the confusion of sound and motion and added the spectacle of large, rising dust clouds. Three geysers, one 30 ft high, suddenly roared into the air at Hot Creek, although none survived more than a few hours. Some new boiling pools appeared, while many existing hot springs and pools became hotter and more active. 

Habitat and movement of lake sturgeon in the upper Mississippi River system, USA

USGS Publications Warehouse

Knights, Brent C.; Vallazza, Jonathon M.; Zigler, Steven J.; Dewey, Michael R.

2002-01-01

Lake sturgeon Acipenser fluvescens, which are now protected from harvest, are considered rare in the upper Mississippi River and little information is available on the remaining populations. Transmitters were implanted into 31 lake sturgeon from two sites in the upper Mississippi River to describe their habitats and movement. The areas surrounding the tagging sites were core areas for both groups of lake sturgeon based on the high use (about 50% of locations by group) and frequent return to these areas by many of the tagged fish. Core areas contained sites with unique hydraulic characteristics, such that depositional substrates were common yet flow was present; these areas probably provide important feeding habitat for lake sturgeon. Minimal geographical overlap in range occurred between groups, suggesting that river reaches and associated core areas were unique to groups or substocks of fish. Lake sturgeon exhibited complex movement behaviors and had ranges of 3-198 km (median, 56 km) during the study. Tagged fish moved both downstream and upstream through upper Mississippi River navigation dams. However, dams appeared to be intermittent barriers to upstream passage because upstream passage events (10 fish, 19 passages) were fewer than downstream events (13 fish, 35 passages). Extensive use of the Wisconsin River by one group of lake sturgeon tagged in the upper Mississippi River has implications regarding management of a threatened population that transcends regulatory boundaries. Our study indicates that lake sturgeon In the upper Mississippi River system share many movement and habitat use characteristics with populations in other systems. However, significant data gaps preclude development of cogent management strategies, including information on population numbers and dynamics, identification of spawning areas, relations between groups, and assessment of the effects of commercial navigation.

Hydrologic and Water-Quality Responses in Shallow Ground Water Receiving Stormwater Runoff and Potential Transport of Contaminants to Lake Tahoe, California and Nevada, 2005-07

USGS Publications Warehouse

Green, Jena M.; Thodal, Carl E.; Welborn, Toby L.

2008-01-01

Clarity of Lake Tahoe, California and Nevada has been decreasing due to inflows of sediment and nutrients associated with stormwater runoff. Detention basins are considered effective best management practices for mitigation of suspended sediment and nutrients associated with runoff, but effects of infiltrated stormwater on shallow ground water are not known. This report documents 2005-07 hydrogeologic conditions in a shallow aquifer and associated interactions between a stormwater-control system with nearby Lake Tahoe. Selected chemical qualities of stormwater, bottom sediment from a stormwater detention basin, ground water, and nearshore lake and interstitial water are characterized and coupled with results of a three-dimensional, finite-difference, mathematical model to evaluate responses of ground-water flow to stormwater-runoff accumulation in the stormwater-control system. The results of the ground-water flow model indicate mean ground-water discharge of 256 acre feet per year, contributing 27 pounds of phosphorus and 765 pounds of nitrogen to Lake Tahoe within the modeled area. Only 0.24 percent of this volume and nutrient load is attributed to stormwater infiltration from the detention basin. Settling of suspended nutrients and sediment, biological assimilation of dissolved nutrients, and sorption and detention of chemicals of potential concern in bottom sediment are the primary stormwater treatments achieved by the detention basins. Mean concentrations of unfiltered nitrogen and phosphorus in inflow stormwater samples compared to outflow samples show that 55 percent of nitrogen and 47 percent of phosphorus are trapped by the detention basin. Organic carbon, cadmium, copper, lead, mercury, nickel, phosphorus, and zinc in the uppermost 0.2 foot of bottom sediment from the detention basin were all at least twice as concentrated compared to sediment collected from 1.5 feet deeper. Similarly, concentrations of 28 polycyclic aromatic hydrocarbon compounds were

Sphene and zircon in the Highland Range volcanic sequence (Miocene, southern Nevada, USA): Elemental partitioning, phase relations, and influence on evolution of silicic magma

USGS Publications Warehouse

Colombini, L.L.; Miller, C.F.; Gualda, G.A.R.; Wooden, J.L.; Miller, J.S.

2011-01-01

Sphene is prominent in Miocene plutonic rocks ranging from diorite to granite in southern Nevada, USA, but it is restricted to rhyolites in coeval volcanic sequences. In the Highland Range volcanic sequence, sphene appears as a phenocryst only in the most evolved rocks (72-77 mass% SiO2; matrix glass 77-78 mass% SiO2). Zr-in-sphene temperatures of crystallization are mostly restricted to 715 and 755??C, in contrast to zircon (710-920??C, Ti-in-zircon thermometry). Sphene rim/glass Kds for rare earth elements are extremely high (La 120, Sm 1200, Gd 1300, Lu 240). Rare earth elements, especially the middle REE (MREE), decrease from centers to rims of sphene phenocrysts along with Zr, demonstrating the effect of progressive sphene fractionation. Whole rocks and glasses have MREE-depleted, U-shaped REE patterns as a consequence of sphene fractionation. Within the co-genetic, sphene-rich Searchlight pluton, only evolved leucogranites show comparable MREE depletion. These results indicate that sphene saturation in intruded and extruded magmas occurred only in highly evolved melts: abundant sphene in less silicic plutonic rocks represents a late-stage 'bloom' in fractionated interstitial melt. ?? 2011 Springer-Verlag.

Are Sierran Lakes Warming as a Result of Climate Change? The Effects of Climate Warming and Variation in Precipitation on Water Temperature in a Snowmelt-Dominated Lake

NASA Astrophysics Data System (ADS)

Sadro, S.; Melack, J. M.; Sickman, J. O.; Skeen, K.

2016-12-01

Water temperature regulates a broad range of fundamental ecosystem processes in lakes. While climate can be an important factor regulating lake temperatures, heterogeneity in the warming response of lakes is large, and variation in precipitation is rarely considered. We analyzed three decades of climate and water temperature data from a high-elevation catchment in the southern Sierra Nevada of California to illustrate the magnitude of warming taking place during different seasons and the role of precipitation in regulating lake temperatures. Significant climate warming trends were evident during all seasons except spring. Nighttime rates of climate warming were approximately 25% higher than daytime rates. Spatial patterns in warming were elevation dependent, with rates of temperature increase higher at sites above 2800 m.a.s.l. than below. Although interannual variation in snow deposition was high, the frequency and severity of recent droughts has contributed to a significant 3.4 mm year -1 decline in snow water equivalent over the last century. Snow accumulation, more than any other climate factor, regulated lake temperature; 94% of variation in summer lake temperature was regulated by precipitation as snow. For every 100 mm decrease in snow water equivalent there was a 0.62 ° increase in lake temperature. Drought years amplify warming in lakes by reducing the role of cold spring meltwaters in lake energy budgets and prolonging the ice-free period during which lakes warm. The combination of declining winter snowpack and warming air temperatures has the capacity to amplify the effect of climate warming on lake temperatures during drought years. Interactions among climatic factors need to be considered when evaluating ecosystem level effects, especially in mountain regions. For mountain lakes already affected by drought, continued climate warming during spring and autumn has the greatest potential to impact mean lake temperatures.

Meta-analysis of California Spotted Owl (Strix occidentalis occidentalis) territory occupancy in the Sierra Nevada: habitat associations and their implications for forest management

Treesearch

Douglas J. Tempel; John J. Keane; R. J. Gutierrez; Jared D. Wolfe; Gavin M. Jones; Alexander Koltunov; Carlos M. Ramirez; William J. Berigan; Claire V. Gallagher; Thomas E. Munton; Paula A. Shaklee; Sheila A. Whitmore; M. Zachariah Peery

2016-01-01

We assessed the occupancy dynamics of 275 California Spotted Owl (Strix occidentalis occidentalis) territories in 4 study areas in the Sierra Nevada, California, USA, from 1993 to 2011. We used Landsat data to develop maps of canopy cover for each study area, which we then used to quantify annual territory-specific habitat...

Landscape Sources, Ecological Effects, and Management of Nutrients in Lakes of Northeastern USA

EPA Science Inventory

Lakes face escalating pressures associated with land cover change and growing human populations. Ecological responses provide context for identifying stressor severity, land use impacts, and management effectiveness. We used EPA National Lakes Assessment data and GIS to develop i...

Nevada gaming: revenues and taxes (1945-95).

PubMed

DePolo, R; Pingle, M

1997-01-01

In 1931, Nevada legalized casino gambling, an act which allowed its "gaming industry" to develop. Because many jurisdictions outside Nevada are now embracing legalized gambling as a path to a brighter economic future and because this proliferation presents Nevada with new challenges and opportunities, it is a good time to review the Nevada experience. Here, the focus is on gaming revenues and gaming tax collections during the 1945-95 period. We find that the growth rate of Nevada's gaming industry has slowed over time, with the relative importance of gaming in the Nevada economy peaking in the late 1970's. The Nevada economy has since been gradually diversifying, something which will increasingly pressure Nevadans to look for government revenue sources other than gaming if current levels of government services are to be maintained.

Ancient human mitochondrial DNA and radiocarbon analysis of archived quids from the Mule Spring Rockshelter, Nevada, USA.

PubMed

Hamilton-Brehm, Scott D; Hristova, Lidia T; Edwards, Susan R; Wedding, Jeffrey R; Snow, Meradeth; Kruger, Brittany R; Moser, Duane P

2018-01-01

Chewed and expectorated quids, indigestible stringy fibers from the roasted inner pulp of agave or yucca root, have proven resilient over long periods of time in dry cave environments and correspondingly, although little studied, are common in archaeological archives. In the late 1960s, thousands of quids were recovered from Mule Spring Rockshelter (Nevada, USA) deposits and stored without consideration to DNA preservation in a museum collection, remaining unstudied for over fifty years. To assess the utility of these materials as repositories for genetic information about past inhabitants of the region and their movements, twenty-one quids were selected from arbitrary excavation depths for detailed analysis. Human mitochondrial DNA sequences from the quids were amplified by PCR and screened for diagnostic single nucleotide polymorphisms. Most detected single nucleotide polymorphisms were consistent with recognized Native American haplogroup subclades B2a5, B2i1, C1, C1c, C1c2, and D1; with the majority of the sample set consistent with subclades C1, C1c, and C1c2. In parallel with the DNA analysis, each quid was radiocarbon dated, revealing a time-resolved pattern of occupancy from 347 to 977 calibrated years before present. In particular, this dataset reveals strong evidence for the presence of haplogroup C1/C1c at the Southwestern edge of the US Great Basin from ~670 to 980 cal YBP, which may temporally correspond with the beginnings of the so-called Numic Spread into the region. The research described here demonstrates an approach which combines targeted DNA analysis with radiocarbon age dating; thus enabling the genetic analysis of archaeological materials of uncertain stratigraphic context. Here we present a survey of the maternal genetic profiles from people who used the Mule Spring Rockshelter and the historic timing of their utilization of a key natural resource.

Does prescribed fire promote resistance to drought in low elevation forests of the Sierra Nevada, California, USA?

USGS Publications Warehouse

van Mantgem, Phillip J.; Caprio, Anthony C.; Stephenson, Nathan L.; Das, Adrian J.

2016-01-01

Prescribed fire is a primary tool used to restore western forests following more than a century of fire exclusion, reducing fire hazard by removing dead and live fuels (small trees and shrubs).  It is commonly assumed that the reduced forest density following prescribed fire also reduces competition for resources among the remaining trees, so that the remaining trees are more resistant (more likely to survive) in the face of additional stressors, such as drought.  Yet this proposition remains largely untested, so that managers do not have the basic information to evaluate whether prescribed fire may help forests adapt to a future of more frequent and severe drought.During the third year of drought, in 2014, we surveyed 9950 trees in 38 burned and 18 unburned mixed conifer forest plots at low elevation (<2100 m a.s.l.) in Kings Canyon, Sequoia, and Yosemite national parks in California, USA.  Fire had occurred in the burned plots from 6 yr to 28 yr before our survey.  After accounting for differences in individual tree diameter, common conifer species found in the burned plots had significantly reduced probability of mortality compared to unburned plots during the drought.  Stand density (stems ha-1) was significantly lower in burned versus unburned sites, supporting the idea that reduced competition may be responsible for the differential drought mortality response.  At the time of writing, we are not sure if burned stands will maintain lower tree mortality probabilities in the face of the continued, severe drought of 2015.  Future work should aim to better identify drought response mechanisms and how these may vary across other forest types and regions, particularly in other areas experiencing severe drought in the Sierra Nevada and on the Colorado Plateau.

Extent of Pleistocene lakes in the western Great Basin

USGS Publications Warehouse

Reheis, Marith C.

1999-01-01

During the Pliocene to middle Pleistocene, pluvial lakes in the western Great Basin repeatedly rose to levels much higher than those of the well-documented late Pleistocene pluvial lakes, and some presently isolated basins were connected. Sedimentologic, geomorphic, and chronologic evidence at sites shown on the map indicates that Lakes Lahontan and Columbus-Rennie were as much as 70 m higher in the early-middle Pleistocene than during their late Pleistocene high stands. Lake Lahontan at its 1400-m shoreline level would submerge present-day Reno, Carson City, and Battle Mountain, and would flood other now-dry basins. To the east, Lakes Jonathan (new name), Diamond, Newark, and Hubbs also reached high stands during the early-middle(?) Pleistocene that were 25-40 m above their late Pleistocene shorelines; at these very high levels, the lakes became temporarily or permanently tributary to the Humboldt River and hence to Lake Lahontan. Such a temporary connection could have permitted fish to migrate from the Humboldt River southward into the presently isolated Newark Valley and from Lake Lahontan into Fairview Valley. The timing of drainage integration also provides suggested maximum ages for fish to populate the basins of Lake Diamond and Lake Jonathan. Reconstructing and dating these lake levels also has important implications for paleoclimate, tectonics, and drainage evolution in the western Great Basin. For example, shorelines in several basins form a stair-step sequence downward with time from the highest levels, thought to have formed at about 650 ka, to the lowest, formed during the late Pleistocene. This descending sequence indicates progressive drying of pluvial periods, possibly caused by uplift of the Sierra Nevada and other western ranges relative to the western Great Basin. However, these effects cannot account for the extremely high lake levels during the early middle Pleistocene; rather, these high levels were probably due to a combination of increased

76 FR 9597 - Notice of Inventory Completion: Denver Museum of Nature & Science, Denver, CO

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-18

... the Duck Valley Reservation, Nevada; Sisseton-Wahpeton Oyate of the Lake Traverse Reservation, South...; Shoshone-Paiute Tribes of the Duck Valley Reservation, Nevada; Sisseton-Wahpeton Oyate of the Lake Traverse...; Shoshone-Paiute Tribes of the Duck Valley Reservation, Nevada; Sisseton-Wahpeton Oyate of the Lake Traverse...

Geologic Map of the Tower Peak Quadrangle, Central Sierra Nevada, California

USGS Publications Warehouse

Wahrhaftig, Clyde

2000-01-01

Introduction The Tower Peak quadrangle, which includes northernmost Yosemite National Park, is located astride the glaciated crest of the central Sierra Nevada and covers an exceptionally well-exposed part of the Sierra Nevada batholith. Granitic plutonic rocks of the batholith dominate the geology of the Tower Peak quadrangle, and at least 18 separate pre-Tertiary intrusive events have been identified. Pre-Cretaceous metamorphic rocks crop out in the quadrangle in isolated roof pendants and septa. Tertiary volcanic rocks cover granitic rocks in the northern part of the quadrangle, but are not considered in this brief summary. Potassium-argon (K-Ar) age determinations for plutonic rocks in the quadrangle range from 83 to 96 million years (Ma), including one of 86 Ma for the granodiorite of Lake Harriet (Robinson and Kistler, 1986). However, a rubidium-strontium whole-rock isochron age of 129 Ma has been obtained for the Lake Harriet pluton (Robinson and Kistler, 1986), which field evidence indicates is the oldest plutonic body within the quadrangle. This suggests that some of the K-Ar ages record an episode of resetting during later thermal events and are too young. The evidence indicates that all the plutonic rocks are of Cretaceous age, with the youngest being the Cathedral Peak Granodiorite at about 83 Ma. The pre-Tertiary rocks of the Tower Peak quadrangle fall into two groups: (1) an L-shaped area of older plutonic and metamorphic rocks, 3 to 10 km wide, that extends diagonally both northeast and southeast from near the center of the quadrangle; and (2) a younger group of large, probably composite intrusions that cover large areas in adjacent quadrangles and extend into the Tower Peak quadrangle from the east, north, and southwest.

Meteorites found on Misfits Flat dry lake, Nevada

NASA Astrophysics Data System (ADS)

Harlan, Scott; Jenniskens, Peter; Zolensky, Michael E.; Yin, Qing-Zhu; Verosub, Kenneth L.; Rowland, Douglas J.; Sanborn, Matthew; Huyskens, Magdalena; Creager, Emily R.; Jull, A. J. Timothy

2016-04-01

Meteorites have been found on the small Misfits Flat dry lakebed near Stagecoach, Nevada (119.382W, +39.348N). Since the first find on Sept. 22, 2013, a total of 58 stones of weathering stage W2/3 with a combined mass of 339 g have been collected in 19 visits to the area. This small (3.3 × 3.6 km) lakebed is now a newly designated dense collection area (DCA). Most meteorites were found in a small 350 × 180 m area along the north shore and most are fragments of several broken individual stones. Three of these fragments were classified as an LL4/5 of shock stage S2, now named Misfits Flat 001, one of which (stone MF33) fell 8.1 ± 1.3 ka ago based on the 14C terrestrial age, assuming it came from a 20-80 cm diameter meteoroid. In addition, a small darkly crusted meteorite MF34, now named Misfits Flat 002, was found 820 m WSW from the main mass. This meteorite is classified as an LL5 ordinary chondrite with shock stage S4/5. The meteorite is saturated in 14C at 63 dpm kg-1, suggesting it originated from the center of a 0.5 m diameter meteoroid, or deep inside a ~1.0 m meteoroid, less than 300 yr ago. Accounts exist of a fireball seen at 13:15 UT on March 2, 1895, that are consistent with the find location of Misfits Flat 002.

Mercury methylation at mercury mines in the Humboldt River Basin, Nevada, USA

USGS Publications Warehouse

Gray, J.E.; Crock, J.G.; Lasorsa, B.K.

2002-01-01

Total Hg and methylmercury concentrations were measured in mine-waste calcines (retorted ore), sediment, and water samples collected in and around abandoned mercury mines in western Nevada to evaluate Hg methylation at the mines and in the Humboldt River Basin. Mine-waste calcines contain total Hg concentrations as high as 14 000 ??g g-1. Stream-sediment samples collected within 1 km of the mercury mines contain total Hg concentrations as high as 170 ??g g-1, whereas stream sediments collected at a distance >5 km from the mines, and those collected from the Humboldt River and regional baseline sites, contain total Hg concentrations 8 km from the nearest mercury mines. Our data indicate little transference of Hg and methylmercury from the sediment to the water column due to the lack of mine runoff in this desert climate.

Effect of Tree-to-Shrub Type Conversion in Lower Montane Forests of the Sierra Nevada (USA) on Streamflow

PubMed Central

Tague, Christina L.; Moritz, Max A.

2016-01-01

Higher global temperatures and increased levels of disturbance are contributing to greater tree mortality in many forest ecosystems. These same drivers can also limit forest regeneration, leading to vegetation type conversion. For the Sierra Nevada of California, little is known about how type conversion may affect streamflow, a critical source of water supply for urban, agriculture and environmental purposes. In this paper, we examined the effects of tree-to-shrub type conversion, in combination with climate change, on streamflow in two lower montane forest watersheds in the Sierra Nevada. A spatially distributed ecohydrologic model was used to simulate changes in streamflow, evaporation, and transpiration following type conversion, with an explicit focus on the role of vegetation size and aspect. Model results indicated that streamflow may show negligible change or small decreases following type conversion when the difference between tree and shrub leaf areas is small, partly due to the higher stomatal conductivity and the deep rooting depth of shrubs. In contrast, streamflow may increase when post-conversion shrubs have a small leaf area relative to trees. Model estimates also suggested that vegetation change could have a greater impact on streamflow magnitude than the direct hydrologic impacts of increased temperatures. Temperature increases, however, may have a greater impact on streamflow timing. Tree-to-shrub type conversion increased streamflow only marginally during dry years (annual precipitation < 800 mm), with most streamflow change observed during wetter years. These modeling results underscore the importance of accounting for changes in vegetation communities to accurately characterize future hydrologic regimes for the Sierra Nevada. PMID:27575592

Effect of Tree-to-Shrub Type Conversion in Lower Montane Forests of the Sierra Nevada (USA) on Streamflow.

PubMed

Bart, Ryan R; Tague, Christina L; Moritz, Max A

2016-01-01

Higher global temperatures and increased levels of disturbance are contributing to greater tree mortality in many forest ecosystems. These same drivers can also limit forest regeneration, leading to vegetation type conversion. For the Sierra Nevada of California, little is known about how type conversion may affect streamflow, a critical source of water supply for urban, agriculture and environmental purposes. In this paper, we examined the effects of tree-to-shrub type conversion, in combination with climate change, on streamflow in two lower montane forest watersheds in the Sierra Nevada. A spatially distributed ecohydrologic model was used to simulate changes in streamflow, evaporation, and transpiration following type conversion, with an explicit focus on the role of vegetation size and aspect. Model results indicated that streamflow may show negligible change or small decreases following type conversion when the difference between tree and shrub leaf areas is small, partly due to the higher stomatal conductivity and the deep rooting depth of shrubs. In contrast, streamflow may increase when post-conversion shrubs have a small leaf area relative to trees. Model estimates also suggested that vegetation change could have a greater impact on streamflow magnitude than the direct hydrologic impacts of increased temperatures. Temperature increases, however, may have a greater impact on streamflow timing. Tree-to-shrub type conversion increased streamflow only marginally during dry years (annual precipitation < 800 mm), with most streamflow change observed during wetter years. These modeling results underscore the importance of accounting for changes in vegetation communities to accurately characterize future hydrologic regimes for the Sierra Nevada.

Guide to the littoral zone vascular flora of Carolina bay lakes (U.S.A.)

PubMed Central

Howell, Nathan; Braham, Richard R

2016-01-01

Abstract Background Carolina bays are elliptic, directionally aligned basins of disputed origin that occur on the Atlantic Coastal Plain from the Delmarva Peninsula to southern Georgia. In southeastern North Carolina, several large, natural, lacustrine systems (i.e., Carolina bay lakes) exist within the geomorphological features known as Carolina bays. Within the current distribution of Carolina bays, Bladen and Columbus counties (North Carolina) contain the only known examples of Carolina bay lakes. The Carolina bay lakes can be split into two major divisions, the “Bladen Lakes Group” which is characterized as being relatively unproductive (dystrophic – oligotrophic), and Lake Waccamaw, which stands alone in Columbus County and is known for its high productivity and species richness. Although there have been several studies conducted on these unique lentic systems, none have documented the flora comprehensively. New information Over the 2013−2014 growing seasons, the littoral zone flora of Carolina bay lakes was surveyed and vouchered. Literature reviews and herbarium crawls complemented this fieldwork to produce an inventory of the vascular plant species. This survey detected 205 taxa (species/subspecies and varieties) in 136 genera and 80 vascular plant families. Thirty-one species (15.2%) are of conservation concern. Lake Waccamaw exhibited the highest species richness with 145 catalogued taxa and 26 species of conservation concern. Across all sites, the Cyperaceae (25 spp.), Poaceae (21 spp.), Asteraceae (13 spp.), Ericaceae (8 spp.), Juncaceae (8 spp.), and Lentibulariaceae (6 spp.) were the six most species-rich vascular plant families encountered. A guide to the littoral zone flora of Carolina bay lakes is presented herein, including dichotomous keys, species accounts (including abundance, habitat, phenology, and exsiccatae), as well as images of living species and vouchered specimens. PMID:27350764

Geothermal GIS coverage of the Great Basin, USA: Defining regional controls and favorable exploration terrains

USGS Publications Warehouse

Coolbaugh, M.F.; Sawatzky, D.L.; Oppliger, G.L.; Minor, T.B.; Raines, G.L.; Shevenell, L.; Blewitt, G.; Louie, J.N.

2003-01-01

A geographic information system (GIS) of geothermal resources, built last year for the state of Nevada, is being expanded to cover the Great Basin, USA. Data from that GIS is being made available to industry, other researchers, and the public via a web site at the Great Basin Center for Geothermal Energy, Reno, Nevada. That web site features a search engine, supports ArcExplorer?? for on-line map construction, and provides downloadable data layers in several formats. Though data collection continues, preliminary analysis has begun. Contour maps of geothermal temperatures, constructed using geothermometer temperatures calculated from a Great Basin geochemical database compiled by the Geo-Heat Center, reveal distinctive trends and patterns. As expected, magmatic-type and extensional-type geothermal systems have profoundly different associations, with magmatic-type systems following major tectonic boundaries, and extensional-type systems associating with regionally high heat flow, thin crust, active faulting, and high extensional strain rates. As described by earlier researchers, including Rowen and Wetlaufer (1981) and Koenig and McNitt (1983), high-temperature (> 100??C) geothermal systems appear to follow regional northeast trends, most conspicuously including the Humboldt structural zone in Nevada, the "Black Rock-Alvord Desert" trend in Oregon and Nevada, and the "Newcastle-Roosevelt" trend in Utah and Nevada. Weights-of-evidence analyses confirm a preference of high-temperature geothermal systems for young northeast-trending faults, but the distribution of geothermal systems correlates even better with high rates of crustal extension, as measured from global positioning system (GPS) stations in Nevada. A predictive map of geothermal potential based only on areas of high extensional strain rates and high heat flux does an excellent job of regionally predicting the location of most known geothermal systems in Nevada, and may prove useful in identifying blind

Estimating the designated use attainment decision error rates of US Environmental Protection Agency's proposed numeric total phosphorus criteria for Florida, USA, colored lakes.

PubMed

McLaughlin, Douglas B

2012-01-01

The utility of numeric nutrient criteria established for certain surface waters is likely to be affected by the uncertainty that exists in the presence of a causal link between nutrient stressor variables and designated use-related biological responses in those waters. This uncertainty can be difficult to characterize, interpret, and communicate to a broad audience of environmental stakeholders. The US Environmental Protection Agency (USEPA) has developed a systematic planning process to support a variety of environmental decisions, but this process is not generally applied to the development of national or state-level numeric nutrient criteria. This article describes a method for implementing such an approach and uses it to evaluate the numeric total P criteria recently proposed by USEPA for colored lakes in Florida, USA. An empirical, log-linear relationship between geometric mean concentrations of total P (a potential stressor variable) and chlorophyll a (a nutrient-related response variable) in these lakes-that is assumed to be causal in nature-forms the basis for the analysis. The use of the geometric mean total P concentration of a lake to correctly indicate designated use status, defined in terms of a 20 µg/L geometric mean chlorophyll a threshold, is evaluated. Rates of decision errors analogous to the Type I and Type II error rates familiar in hypothesis testing, and a 3rd error rate, E(ni) , referred to as the nutrient criterion-based impairment error rate, are estimated. The results show that USEPA's proposed "baseline" and "modified" nutrient criteria approach, in which data on both total P and chlorophyll a may be considered in establishing numeric nutrient criteria for a given lake within a specified range, provides a means for balancing and minimizing designated use attainment decision errors. Copyright © 2011 SETAC.

Marine and land active-source seismic investigation of geothermal potential, tectonic structure, and earthquake hazards in Pyramid Lake, Nevada

NASA Astrophysics Data System (ADS)

Eisses, A.; Kell, A. M.; Kent, G.; Driscoll, N. W.; Karlin, R. E.; Baskin, R. L.; Louie, J. N.; Smith, K. D.; Pullammanappallil, S.

2011-12-01

Preliminary slip rates measured across the East Pyramid Lake fault, or the Lake Range fault, help provide new estimates of extension across the Pyramid Lake basin. Multiple stratigraphic horizons spanning 48 ka were tracked throughout the lake, with layer offsets measured across all significant faults in the basin. A chronstratigraphic framework acquired from four sediment cores allows slip rates of the Lake Range and other faults to be calculated accurately. This region of the northern Walker Lake, strategically placed between the right-lateral strike-slip faults of Honey and Eagle Lakes to the north, and the normal fault bounded basins to the southwest (e.g., Tahoe, Carson), is critical in understanding the underlying structural complexity that is not only necessary for geothermal exploration, but also earthquake hazard assessment due to the proximity of the Reno-Sparks metropolitan area. In addition, our seismic CHIRP imaging with submeter resolution allows the construction of the first fault map of Pyramid Lake. The Lake Range fault can be obviously traced west of Anahoe Island extending north along the east end of the lake in numerous CHIRP lines. Initial drafts of the fault map reveal active transtension through a series of numerous, small, northwest striking, oblique-slip faults in the north end of the lake. A previously field mapped northwest striking fault near Sutcliff can be extended into the west end of Pyramid Lake. This fault map, along with the calculated slip rate of the Lake Range, and potentially multiple other faults, gives a clearer picture into understanding the geothermal potential, tectonic regime and earthquake hazards in the Pyramid Lake basin and the northern Walker Lane. These new results have also been merged with seismicity maps, along with focal mechanisms for the larger events to begin to extend our fault map in depth.