77 FR 73411 - Lake Tahoe Basin Federal Advisory Committee (LTBFAC)

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-10

... DEPARTMENT OF AGRICULTURE Forest Service Lake Tahoe Basin Federal Advisory Committee (LTBFAC) AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Lake Tahoe Basin Federal Advisory Committee will meet in South Lake Tahoe, California. This Committee, established by the Secretary of...

76 FR 67132 - Lake Tahoe Basin Federal Advisory Committee (LTFAC)

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-31

... DEPARTMENT OF AGRICULTURE Forest Service Lake Tahoe Basin Federal Advisory Committee (LTFAC) AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Lake Tahoe Federal Advisory Committee will hold a meeting on November 18, 2011 at the Lake Tahoe Basin Management Unit, 35 College Drive...

76 FR 23276 - Lake Tahoe Basin Federal Advisory Committee (LTFAC)

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-26

... DEPARTMENT OF AGRICULTURE Forest Service Lake Tahoe Basin Federal Advisory Committee (LTFAC) AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Lake Tahoe Basin Federal Advisory... Interagency Partnership on the Lake Tahoe Region and other matters raised by the Secretary. DATES: The meeting...

77 FR 42696 - Lake Tahoe Basin Federal Advisory Committee (LTFAC)

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-20

... DEPARTMENT OF AGRICULTURE Forest Service Lake Tahoe Basin Federal Advisory Committee (LTFAC) AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Lake Tahoe Federal Advisory Committee will hold a meeting on August 9, 2012 at the Lake Tahoe Basin Management Unit, 35 College Drive...

76 FR 61074 - Lake Tahoe Basin Federal Advisory Committee (LTFAC)

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-03

... DEPARTMENT OF AGRICULTURE Forest Service Lake Tahoe Basin Federal Advisory Committee (LTFAC) AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Lake Tahoe Federal Advisory Committee will hold a meeting on October 21 or 24, 2011 at the Lake Tahoe Basin Management Unit, 35 College...

76 FR 62038 - Lake Tahoe Basin Federal Advisory Committee (LTFAC)

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-06

... DEPARTMENT OF AGRICULTURE Forest Service Lake Tahoe Basin Federal Advisory Committee (LTFAC) AGENCY: Forest Service, USDA. ACTION: Notice of meeting cancellation. SUMMARY: The Lake Tahoe Federal Advisory Committee meeting that was to be held on October 21 or 24, 2011 at the Lake Tahoe Basin Management...

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.

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.

Historical Orthoimagery of the Lake Tahoe Basin

USGS Publications Warehouse

Soulard, Christopher E.; Raumann, Christian G.

2008-01-01

The U.S. Geological Survey (USGS) Western Geographic Science Center has developed a series of historical digital orthoimagery (HDO) datasets covering part or all of the Lake Tahoe Basin. Three datasets are available: (A) 1940 HDOs for the southern Lake Tahoe Basin, (B) 1969 HDOs for the entire Lake Tahoe Basin, and (C) 1987 HDOs for the southern Lake Tahoe Basin. The HDOs (for 1940, 1969, and 1987) were compiled photogrammically from aerial photography with varying scales, camera characteristics, image quality, and capture dates. The resulting datasets have a 1-meter horizontal resolution. Precision-corrected Ikonos multispectral satellite imagery was used as a substitute for HDOs/DOQs for the 2002 imagery date, but these data are not available for download in this series due to licensing restrictions. The projection of the HDO data is set to UTM Zone 10, NAD 1983. The data for each of the three available dates are clipped into files that spatially approximate the 3.75-minute USGS quarter quadrangles (roughly 3,000 to 4,000 hectares), and have roughly 100 pixels (or 100 meters) of overlap to facilitate combining the files into larger regions without data gaps. The files are named after 3.75-minute USGS quarter quadrangles that cover the same general spatial extent. These files are available in the ERDAS Imagine (.img) format.

78 FR 70012 - Lake Tahoe Basin Management Unit, California, Land Management Plan Revision

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-22

... DEPARTMENT OF AGRICULTURE Forest Service Lake Tahoe Basin Management Unit, California, Land Management Plan Revision AGENCY: Lake Tahoe Basin Management Unit, Forest Service, USDA. ACTION: Notice of... for the Lake Tahoe Basin Management Unit (LTBMU) Land Management Plan Revision available for the 60...

Aircraft measurements of nitrogen and phosphorus in and around the Lake Tahoe Basin: implications for possible sources of atmospheric pollutants to Lake Tahoe.

PubMed

Zhang, Qi; Carroll, John J; Dixon, Alan J; Anastasio, Cort

2002-12-01

Atmospheric deposition of nitrogen (N) and phosphorus (P) into Lake Tahoe appears to have been a major factor responsible for the shifting of the lake's nutrient response from N-limited to P-limited. To characterize atmospheric N and P in and around the Lake Tahoe Basin during summer, samples were collected using an instrumented aircraft flown over three locations: the Sierra Nevada foothills east of Sacramento ("low-Sierra"), further east and higher in the Sierra ("mid-Sierra"), and in the Tahoe Basin. Measurements were also made within the smoke plume downwind of an intense forest fire just outside the Tahoe Basin. Samples were collected using a denuder-filter pack sampling system (DFP) and analyzed for gaseous and water-soluble particle components including HNO3/ NO3-, NH3 /NH4+, organic N (ON), total N, SRP (soluble reactive phosphate) and total P. The average total gaseous and particulate N concentrations (+/- 1sigma) measured over the low- and mid-Sierra were 660 (+/- 270) and 630 (+/- 350) nmol N/m3-air, respectively. Total airborne N concentrations in the Tahoe samples were one-half to one-fifth of these values. The forest fire plume had the highest concentration of atmospheric N (860 nmol N/m3-air) and a greater contribution of organic N (ON) to the total N compared to nonsmoky conditions. Airborne P was rarely observed over the low- and mid-Sierra but was present at low concentrations over Lake Tahoe, with average +/- 1sigma) concentrations of 2.3 +/- 2.9 and 2.8 +/- 0.8 nmol P/m3-air under typical clear air and slightly smoky air conditions, respectively. Phosphorus in the forestfire plume was present at concentrations approximately 10 times greater than over the Tahoe Basin. P in these samples included both fine and coarse particulate phosphate as well as unidentified, possibly organic, gaseous P species. Overall, our results suggest that out-of-basin emissions could be significant sources of nitrogen to Lake Tahoe during the summer and that forest

Structural Constraints and Earthquake Recurrence Estimates for the West Tahoe-Dollar Point Fault, Lake Tahoe Basin, California

NASA Astrophysics Data System (ADS)

Maloney, J. M.; Driscoll, N. W.; Kent, G.; Brothers, D. S.; Baskin, R. L.; Babcock, J. M.; Noble, P. J.; Karlin, R. E.

2011-12-01

Previous work in the Lake Tahoe Basin (LTB), California, identified the West Tahoe-Dollar Point Fault (WTDPF) as the most hazardous fault in the region. Onshore and offshore geophysical mapping delineated three segments of the WTDPF extending along the western margin of the LTB. The rupture patterns between the three WTDPF segments remain poorly understood. Fallen Leaf Lake (FLL), Cascade Lake, and Emerald Bay are three sub-basins of the LTB, located south of Lake Tahoe, that provide an opportunity to image primary earthquake deformation along the WTDPF and associated landslide deposits. We present results from recent (June 2011) high-resolution seismic CHIRP surveys in FLL and Cascade Lake, as well as complete multibeam swath bathymetry coverage of FLL. Radiocarbon dates obtained from the new piston cores acquired in FLL provide age constraints on the older FLL slide deposits and build on and complement previous work that dated the most recent event (MRE) in Fallen Leaf Lake at ~4.1-4.5 k.y. BP. The CHIRP data beneath FLL image slide deposits that appear to correlate with contemporaneous slide deposits in Emerald Bay and Lake Tahoe. A major slide imaged in FLL CHIRP data is slightly younger than the Tsoyowata ash (7950-7730 cal yrs BP) identified in sediment cores and appears synchronous with a major Lake Tahoe slide deposit (7890-7190 cal yrs BP). The equivalent age of these slides suggests the penultimate earthquake on the WTDPF may have triggered them. If correct, we postulate a recurrence interval of ~3-4 k.y. These results suggest the FLL segment of the WTDPF is near its seismic recurrence cycle. Additionally, CHIRP profiles acquired in Cascade Lake image the WTDPF for the first time in this sub-basin, which is located near the transition zone between the FLL and Rubicon Point Sections of the WTDPF. We observe two fault-strands trending N45°W across southern Cascade Lake for ~450 m. The strands produce scarps of ~5 m and ~2.7 m, respectively, on the lake

78 FR 71026 - Environmental Impact Statement for the Lake Tahoe Passenger Ferry Project, Placer and El Dorado...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-27

... Lake Tahoe Passenger Ferry Project, Placer and El Dorado Counties and City of South Lake Tahoe... Statement (EIS) for the proposed Lake Tahoe Passenger Ferry Project. The project consists of a cross- lake ferry service with a South Shore Ferry Terminal at the Ski Run Marina in South Lake Tahoe, El Dorado...

Gasoline-related organics in Lake Tahoe before and after prohibition of carbureted two-stroke engines

USGS Publications Warehouse

Lico, M.S.

2004-01-01

On June 1, 1999, carbureted two-stroke engines were banned on waters within the Lake Tahoe Basin of California and Nevada. The main gasoline components MTBE (methyl tert-butyl ether) and BTEX (benzene, toluene, ethylbenzene, and xylenes) were present at detectable concentrations in all samples taken from Lake Tahoe during 1997-98 prior to the ban. Samples taken from 1999 through 2001 after the ban contained between 10 and 60 percent of the pre-ban concentrations of these compounds, with MTBE exhibiting the most dramatic change (a 90 percent decrease). MTBE and BTEX concentrations in water samples from Lake Tahoe and Lower Echo Lake were related to the amount of boat use at the sampling sites. Polycyclic aromatic hydrocarbon (PAH) compounds are produced by high-temperature pyrolytic reactions. They were sampled using semipermeable membrane sampling devices in Lake Tahoe and nearby Donner Lake, where carbureted two-stroke engines are legal. PAHs were detected in all samples taken from Lake Tahoe and Donner Lake. The number of PAH compounds and their concentrations are related to boat use. The highest concentrations of PAH were detected in samples from two heavily used boating areas, Tahoe Keys Marina and Donner Lake boat ramp. Other sources of PAH, such as atmospheric deposition, wood smoke, tributary streams, and automobile exhaust do not contribute large amounts of PAH to Lake Tahoe. Similar numbers of PAH compounds and concentrations were found in Lake Tahoe before and after the ban of carbureted two-stroke engines. ?? by the North American Lake Management Society 2004.

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/.

Estimated flood flows in the Lake Tahoe basin, California and Nevada

USGS Publications Warehouse

Crompton, E. James; Hess, Glen W.; Williams, Rhea P.

2002-01-01

Lake Tahoe, the largest alpine lake in North America, covers about 192 square miles (mi2) of the 506-mi2 Lake Tahoe Basin, which straddles the border between California and Nevada (Fig. 1). In cooperation with the Nevada Department of Transportation (NDOT), the U.S. Geological Survey (USGS) estimates the flood frequencies of the streams that enter the lake. Information about potential flooding of these streams is used by NDOT in the design and construction of roads and highways in the Nevada portion of the basin. The stream-monitoring network in the Lake Tahoe Basin is part of the Lake Tahoe Interagency Monitoring Program (LTIMP), which combines the monitoring and research efforts of various Federal, State, and regional agencies, including both USGS and NDOT. The altitude in the basin varies from 6,223 feet (ft) at the lake's natural rim to over 10,000 ft along the basin's crest. Precipitation ranges from 40 inches per year (in/yr) on the eastern side to 90 in/yr on the western side (Crippen and Pavelka, 1970). Most of the precipitation comes during the winter months as snow. Precipitation that falls from June through September accounts for less than 20 percent of the annual total.

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

NASA Astrophysics Data System (ADS)

Seaman, Tyler

--Nevada border just north of Lake Tahoe. Focal mechanism and stress inversion results, based on the variance of the P-axis orientation, reveal a strike-slip dominated region directly north of Lake Tahoe that abruptly transitions northeastward to a transtentional regime along the Sierra front (i.e., in the hanging wall regime of the Sierran block). The majority of earthquakes used in the relocation and stress analysis occurs within a time period that includes unusual upper mantle/lower-crustal (˜30 km depth) dike injection events: 1) 2003 North Lake Tahoe and 2) 2011-2012 Sierra Valley, CA, that we interpret to be rift-related processes along the eastern Sierra Nevada microplate. Earthquake relocations for events shallower than about 18 km depth (the seismogenic depth determined in this study in the north Lake Tahoe area) cluster along high-angle fault structures, primarily in the footwall of the Sierra Nevada block. This new analysis isolates areas of distinctly strike-slip versus transtensional stress regimes, based on the variability of the P-axis plunge, that straddle the Sierra Nevada--Great Basin transition zone at the latitude of Lake Tahoe.

The Lake Tahoe Basin Land Use Simulation Model

USGS Publications Warehouse

Forney, William M.; Oldham, I. Benson

2011-01-01

This U.S. Geological Survey Open-File Report describes the final modeling product for the Tahoe Decision Support System project for the Lake Tahoe Basin funded by the Southern Nevada Public Land Management Act and the U.S. Geological Survey's Geographic Analysis and Monitoring Program. This research was conducted by the U.S. Geological Survey Western Geographic Science Center. The purpose of this report is to describe the basic elements of the novel Lake Tahoe Basin Land Use Simulation Model, publish samples of the data inputs, basic outputs of the model, and the details of the Python code. The results of this report include a basic description of the Land Use Simulation Model, descriptions and summary statistics of model inputs, two figures showing the graphical user interface from the web-based tool, samples of the two input files, seven tables of basic output results from the web-based tool and descriptions of their parameters, and the fully functional Python code.

78 FR 39997 - Safety Zone; Fourth of July Fireworks Display, Tahoe City, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-03

... Zone; Fourth of July Fireworks Display, Tahoe City, CA AGENCY: Coast Guard, DHS. ACTION: Notice of... Fireworks Display, Tahoe City, CA in the Captain of the Port, San Francisco area of responsibility during... launch site off of Tahoe City, CA in approximate position 39[deg]10'09'' N, 120[deg]08'16'' W (NAD 83...

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.

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

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

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...

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

78 FR 69363 - Lake Tahoe Basin Management Unit, California, Heavenly Mountain Resort Epic Discovery Project

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-19

... DEPARTMENT OF AGRICULTURE Forest Service Lake Tahoe Basin Management Unit, California, Heavenly Mountain Resort Epic Discovery Project AGENCY: Lake Tahoe Basin Management Unit, Forest Service, USDA...: The Epic Discovery Project is intended to enhance summer activities in response to the USDA Forest...

Angora Fire, Lake Tahoe

NASA Technical Reports Server (NTRS)

2007-01-01

On the weekend of June 23, 2007, a wildfire broke out south of Lake Tahoe, which stretches across the California-Nevada border. By June 28, the Angora Fire had burned more than 200 homes and forced some 2,000 residents to evacuate, according to The Seattle Times and the Central Valley Business Times. On June 27, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this image of the burn scar left by the Angora fire. The burn scar is dark gray, or charcoal. Water bodies, including the southern tip of Lake Tahoe and Fallen Leaf Lake, are pale silvery blue, the silver color a result of sunlight reflecting off the surface of the water. Vegetation ranges in color from dark to bright green. Streets are light gray, and the customary pattern of meandering residential streets and cul-de-sacs appears throughout the image, including the area that burned. The burn scar shows where the fire obliterated some of the residential areas just east of Fallen Leaf Lake. According to news reports, the U.S. Forest Service had expressed optimism about containing the fire within a week of the outbreak, but a few days after the fire started, it jumped a defense, forcing the evacuation of hundreds more residents. Strong winds that had been forecast for June 27, however, did not materialize, allowing firefighters to regain ground in controlling the blaze. On June 27, authorities hoped that the fire would be completely contained by July 3. According to estimates provided in the daily report from the National Interagency Fire Center, the fire had burned 3,100 acres (about 12.5 square kilometers) and was about 55 percent contained as of June 28. Some mandatory evacuations remained in effect. NASA image by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.

43 CFR 44.41 - How does the Department calculate payments for lands in the Redwood National Park or Lake Tahoe...

Code of Federal Regulations, 2010 CFR

2010-10-01

... for lands in the Redwood National Park or Lake Tahoe Basin? 44.41 Section 44.41 Public Lands: Interior... Governments for Interest in Lands in the Redwood National Park Or Lake Tahoe Basin § 44.41 How does the Department calculate payments for lands in the Redwood National Park or Lake Tahoe Basin? (a) The Department...

43 CFR 44.41 - How does the Department calculate payments for lands in the Redwood National Park or Lake Tahoe...

Code of Federal Regulations, 2013 CFR

2013-10-01

... for lands in the Redwood National Park or Lake Tahoe Basin? 44.41 Section 44.41 Public Lands: Interior... Governments for Interest in Lands in the Redwood National Park Or Lake Tahoe Basin § 44.41 How does the Department calculate payments for lands in the Redwood National Park or Lake Tahoe Basin? (a) The Department...

43 CFR 44.41 - How does the Department calculate payments for lands in the Redwood National Park or Lake Tahoe...

Code of Federal Regulations, 2012 CFR

2012-10-01

... for lands in the Redwood National Park or Lake Tahoe Basin? 44.41 Section 44.41 Public Lands: Interior... Governments for Interest in Lands in the Redwood National Park Or Lake Tahoe Basin § 44.41 How does the Department calculate payments for lands in the Redwood National Park or Lake Tahoe Basin? (a) The Department...

43 CFR 44.41 - How does the Department calculate payments for lands in the Redwood National Park or Lake Tahoe...

Code of Federal Regulations, 2014 CFR

2014-10-01

... for lands in the Redwood National Park or Lake Tahoe Basin? 44.41 Section 44.41 Public Lands: Interior... Governments for Interest in Lands in the Redwood National Park Or Lake Tahoe Basin § 44.41 How does the Department calculate payments for lands in the Redwood National Park or Lake Tahoe Basin? (a) The Department...

43 CFR 44.41 - How does the Department calculate payments for lands in the Redwood National Park or Lake Tahoe...

Code of Federal Regulations, 2011 CFR

2011-10-01

... for lands in the Redwood National Park or Lake Tahoe Basin? 44.41 Section 44.41 Public Lands: Interior... Governments for Interest in Lands in the Redwood National Park Or Lake Tahoe Basin § 44.41 How does the Department calculate payments for lands in the Redwood National Park or Lake Tahoe Basin? (a) The Department...

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.

Surface ozone in the Lake Tahoe Basin

Treesearch

Joel D. Burley; Sandra Theiss; Andrzej Bytnerowicz; Alan Gertler; Susan Schilling; Barbara Zielinska

2015-01-01

Surface ozone (O3) concentrations were measured in and around the Lake Tahoe Basin using both active monitors (2010) and passive samplers (2002, 2010). The 2010 data from active monitors indicate average summertime diurnal maxima of approximately 50–55 ppb. Some site-to-site variability is observed within the Basin during the well-mixed hours of...

The Impact of Meteorology on Ozone Levels in the Lake Tahoe Basin

NASA Astrophysics Data System (ADS)

Theiss, Sandra

The Lake Tahoe Basin is located on the California-Nevada border and occasionally experiences elevated levels of ozone exceeding the 70 ppb California Air Resources Board (CARB) ambient air quality standard (8-hour average). Previous studies indicate that both the local generation of ozone in the Basin and long-range transport from out-of-Basin sources are important in contributing to ozone exceedances, but little is known about the impact of meteorology on the distribution of ozone source regions. In order to develop a better understanding of the factors affecting ozone levels and sources in the Lake Tahoe Basin, this study combines observational data from a 2010 and 2012 summer field campaigns, HYSPLIT back trajectories, and WRF model output to examine the meteorological influences of ozone transport in the topographically complex Lake Tahoe Basin. Findings from the field work portions of this study include enhanced background ozone levels at higher elevations, the local circulation pattern of lake breezes occurring at Lake level sites, and an indication that ozone precursors are coming off the Lake. Our analysis also showed that if transport of ozone does occur, it is more likely to come from the San Joaquin Valley to the south rather than originate in the large cities to the west, such as Sacramento and San Francisco. Analysis of modeled PBL schemes as compared with observational data showed that the ACM2 PBL scheme best represented the geographical domain. The ACM2 PBL scheme was then used to show wind circulation patterns in the Lake Tahoe Basin and concluded that there is decent vertical mixing over the Basin and no indication of ozone transport from the west however some indication of transport from the east. Overall this study concludes that transport from the west is less significant than transport from the south and east, and that transport only influences ozone values at higher elevations. Within the Basin itself (at lower elevations), local factors

43 CFR 44.40 - How does the Department process payments for lands in the Redwood National Park or Lake Tahoe Basin?

Code of Federal Regulations, 2012 CFR

2012-10-01

... for lands in the Redwood National Park or Lake Tahoe Basin? 44.40 Section 44.40 Public Lands: Interior... Governments for Interest in Lands in the Redwood National Park Or Lake Tahoe Basin § 44.40 How does the Department process payments for lands in the Redwood National Park or Lake Tahoe Basin? This section...

43 CFR 44.40 - How does the Department process payments for lands in the Redwood National Park or Lake Tahoe Basin?

Code of Federal Regulations, 2014 CFR

2014-10-01

... for lands in the Redwood National Park or Lake Tahoe Basin? 44.40 Section 44.40 Public Lands: Interior... Governments for Interest in Lands in the Redwood National Park Or Lake Tahoe Basin § 44.40 How does the Department process payments for lands in the Redwood National Park or Lake Tahoe Basin? This section...

43 CFR 44.40 - How does the Department process payments for lands in the Redwood National Park or Lake Tahoe Basin?

Code of Federal Regulations, 2013 CFR

2013-10-01

... for lands in the Redwood National Park or Lake Tahoe Basin? 44.40 Section 44.40 Public Lands: Interior... Governments for Interest in Lands in the Redwood National Park Or Lake Tahoe Basin § 44.40 How does the Department process payments for lands in the Redwood National Park or Lake Tahoe Basin? This section...

43 CFR 44.40 - How does the Department process payments for lands in the Redwood National Park or Lake Tahoe Basin?

Code of Federal Regulations, 2010 CFR

2010-10-01

... for lands in the Redwood National Park or Lake Tahoe Basin? 44.40 Section 44.40 Public Lands: Interior... Governments for Interest in Lands in the Redwood National Park Or Lake Tahoe Basin § 44.40 How does the Department process payments for lands in the Redwood National Park or Lake Tahoe Basin? This section...

43 CFR 44.40 - How does the Department process payments for lands in the Redwood National Park or Lake Tahoe Basin?

Code of Federal Regulations, 2011 CFR

2011-10-01

... for lands in the Redwood National Park or Lake Tahoe Basin? 44.40 Section 44.40 Public Lands: Interior... Governments for Interest in Lands in the Redwood National Park Or Lake Tahoe Basin § 44.40 How does the Department process payments for lands in the Redwood National Park or Lake Tahoe Basin? This section...

Tsunami-generated sediment wave channels at Lake Tahoe, California-Nevada, USA

USGS Publications Warehouse

Moore, James G.; Schweickert, Richard A.; Kitts, Christopher A.

2014-01-01

A gigantic ∼12 km3 landslide detached from the west wall of Lake Tahoe (California-Nevada, USA), and slid 15 km east across the lake. The splash, or tsunami, from this landslide eroded Tioga-age moraines dated as 21 ka. Lake-bottom short piston cores recovered sediment as old as 12 ka that did not reach landslide deposits, thereby constraining the landslide age as 21–12 ka.Movement of the landslide splashed copious water onto the countryside and lowered the lake level ∼10 m. The sheets of water that washed back into the lake dumped their sediment load at the lowered shoreline, producing deltas that merged into delta terraces. During rapid growth, these unstable delta terraces collapsed, disaggregated, and fed turbidity currents that generated 15 subaqueous sediment wave channel systems that ring the lake and descend to the lake floor at 500 m depth. Sheets of water commonly more than 2 km wide at the shoreline fed these systems. Channels of the systems contain sediment waves (giant ripple marks) with maximum wavelengths of 400 m. The lower depositional aprons of the system are surfaced by sediment waves with maximum wavelengths of 300 m.A remarkably similar, though smaller, contemporary sediment wave channel system operates at the mouth of the Squamish River in British Columbia. The system is generated by turbidity currents that are fed by repeated growth and collapse of the active river delta. The Tahoe splash-induced backwash was briefly equivalent to more than 15 Squamish Rivers in full flood and would have decimated life in low-lying areas of the Tahoe region.

Fire near South Lake Tahoe, California

NASA Technical Reports Server (NTRS)

2007-01-01

A destructive forest fire that broke out June 24, 2007 near South Lake Tahoe, Calif., continued to burn June 27 when this image was acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer instrument on NASA's Terra satellite. As of June 28, the fire had destroyed about 230 residences and other buildings. In all, about 2,000 people were evacuated, according to South Lake Tahoe Police. The blaze has charred more than 3,100 acres -- about 4.8 square miles -- and was 60 percent contained on June 28. In this ASTER image, the burned area is in gray, a combination of burned forest and some smoke, between Fallen Leaf Lake and the Tahoe Airport.

With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra spacecraft. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

Size: 15 by 15 kilometers (9.3 by 9.3 miles

Stormwater and fire as sources of black carbon nanoparticles to Lake Tahoe.

PubMed

Bisiaux, Marion M; Edwards, Ross; Heyvaert, Alan C; Thomas, James M; Fitzgerald, Brian; Susfalk, Richard B; Schladow, S Geoffrey; Thaw, Melissa

2011-03-15

Emitted to the atmosphere through fire and fossil fuel combustion, refractory black carbon nanoparticles (rBC) impact human health, climate, and the carbon cycle. Eventually these particles enter aquatic environments, where they may affect the fate of other pollutants. While ubiquitous, the particles are still poorly characterized in freshwater systems. Here we present the results of a study determining rBC in waters of the Lake Tahoe watershed in the western United States from 2007 to 2009. The study period spanned a large fire within the Tahoe basin, seasonal snowmelt, and a number of storm events, which resulted in pulses of urban runoff into the lake with rBC concentrations up to 4 orders of magnitude higher than midlake concentrations. The results show that rBC pulses from both the fire and urban runoff were rapidly attenuated suggesting unexpected aggregation or degradation of the particles. We find that those processes prevent rBC concentrations from building up in the clear and oligotrophic Lake Tahoe. This rapid removal of rBC soon after entry into the lake has implications for the transport of rBC in the global aquatic environment and the flux of rBC from continents to the global ocean.

Finding balance between fire hazard reduction and erosion control in the Lake Tahoe Basin, California–Nevada

Treesearch

Nicolas M. Harrison; Andrew P. Stubblefield; J. Morgan Varner; Eric E. Knapp

2016-01-01

The 2007 Angora Fire served as a stark reminder of the need for fuel reduction treatments in the Lake Tahoe Basin, California–Nevada, USA. Concerns exist, however, that the corresponding removal of forest floor fuels could increase erosion rates, negatively affecting the clarity of Lake Tahoe. To quantify trade-offs between fuel reduction and erosion, we conducted...

Evaluating a Lake Tahoe nearshore assessment strategy: A circumnavigation survey, August 2011

EPA Science Inventory

We had the opportunity to apply a high-resolution nearshore sampling strategy, developed in the US/Canadian Laurentian Great Lakes, to Lake Tahoe. The strategy uses towed in situ sensors (physico-chemistry and biology) oscillated from near surface to near bottom while a vessel i...

77 FR 28770 - Safety Zone; Red, White, and Tahoe Blue Fireworks, Incline Village, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-16

... of Obexer's Marina in Homewood, CA at position 39[deg]04'55'' N, 120[deg]09'25'' W (NAD 83). From 5 a... off of Incline Village, CA at position 39[deg]14'14'' N, 119[deg]56'56'' W (NAD 83) where it will...,000 feet at position 39[deg]14'14'' N, 119[deg]56'56'' W (NAD 83) for the Red, White, and Tahoe Blue...

The Effectiveness of Cattlemans Detention Basin, South Lake Tahoe, California

USGS Publications Warehouse

Green, Jena M.

2006-01-01

Lake Tahoe (Nevada-California) has been designated as an 'outstanding national water resource' by the U.S. Environmental Protection Agency, in part, for its exceptional clarity. Water clarity in Lake Tahoe, however, has been declining at a rate of about one foot per year for more than 35 years. To decrease the amount of sediment and nutrients delivered to the lake by way of alpine streams, wetlands and stormwater detention basins have been installed at several locations around the lake. Although an improvement in stormwater and snowmelt runoff quality has been measured, the effectiveness of the detention basins for increasing the clarity of Lake Tahoe needs further study. It is possible that poor ground-water quality conditions exist beneath the detention basins and adjacent wetlands and that the presence of the basins has altered ground-water flow paths to nearby streams. A hydrogeochemical and ground-water flow modeling study was done at Cattlemans detention basin, situated adjacent to Cold Creek, a tributary to Lake Tahoe, to determine whether the focusing of storm and snowmelt runoff into a confined area has (1) modified the ground-water flow system beneath the detention basin and affected transport of sediment and nutrients to nearby streams and (2) provided an increased source of solutes which has changed the distribution of nutrients and affected nutrient transport rates beneath the basin. Results of slug tests and ground-water flow modeling suggest that ground water flows unrestricted northwest across the detention basin through the meadow. The modeling also indicates that seasonal flow patterns and flow direction remain similar from year to year under transient conditions. Model results imply that about 34 percent (0.004 ft3/s) of the total ground water within the model area originates from the detention basin. Of the 0.004 ft3/s, about 45 percent discharges to Cold Creek within the modeled area downstream of the detention basin. The remaining 55 percent

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…

A report from Lake Tahoe: Observation from an ideal platform for adaptive management

Treesearch

Dennis D. Murphy; Patricia N. Manley

2009-01-01

The Lake Tahoe basin is in environmenal distress. The lake is still one of the world’s most transparent bodies of water, but its fabled clarity has declined by half since discovery of the high-mountain lake basin by explorers a century and a half ago. At that time, incredibly, objects could be observed on the lake’s bottom a hundred feet down. Two-thirds of the lake’s...

Streamflow and water-quality data for selected watersheds in the Lake Tahoe basin, California and Nevada, through September 1998

USGS Publications Warehouse

Rowe, T.G.; Saleh, D.K.; Watkins, S.A.; Kratzer, C.R.

2002-01-01

The U.S. Geological Survey, in cooperation with the Tahoe Regional Planning Agency, and the University of California, Davis-Tahoe Research Group, has monitored tributaries in the Lake Tahoe Basin since 1988. This monitoring has characterized streamflow and has determined concentrations of nutrients and suspended sediment, which may have contributed to loss of clarity in Lake Tahoe. The Lake Tahoe Interagency Monitoring Program was developed to collect water-quality data in the basin. In 1998, the tributary-monitoring program included 41 water-quality stations in 14 of the 63 watersheds totaling half the area tributary to Lake Tahoe. The monitored watershed areas range from 1.08 square miles for First Creek to 56.5 square miles for the Upper Truckee River.Annual and unit runoff for 20 primary and secondary streamflow gaging stations in 10 selected watersheds are described. Water years 1988-98 were used to compare runoff data. The Upper Truckee River at South Lake Tahoe, Calif., had the highest annual runoff and Logan House Creek near Glenbrook, Nev., had the lowest. Blackwood Creek near Tahoe City, Calif., had the highest unit runoff and Logan House Creek had the lowest. The highest instantaneous peak flow was recorded at Upper Truckee River at South Lake Tahoe during the January 2, 1997, flood event.Certain water-quality measurements were made in the field. Ranges and median values of those measurements are described for 41 stations. Water temperature ranged from 0 to 23?C. Specific conductance ranged from 13 to 900 microsiemens per centimeter at 25?C. pH ranged from 6.7 to 10.6. Dissolved-oxygen concentrations ranged from 5.2 to 12.6 mg/L and from 70 to 157 percent of saturation.Loads, yields, and trends of nutrients and suspended sediment during water years 1988-98 at the streamflow gaging stations also are described. The Upper Truckee River at South Lake Tahoe had the largest median monthly load for five of the six measured nutrients and of suspended sediment

Biotic diversity interfaces with urbanization in the Lake Tahoe basin

Treesearch

Patricia N. Manley; Dennis D. Murphy; Lori A. Campbell; Kirsten E. Heckmann; Susan Merideth; Sean A. Parks; Monte P. Sanford; Matthew D. Schlesinger

2006-01-01

In the Lake Tahoe Basin, the retention of native ecosystems within urban areas may greatly enhance the landscape’s ability to maintain biotic diversity. Our study of plant, invertebrate and vertebrate species showed that many native species were present in remnant forest stands in developed areas; however, their richness and abundance declined in association with...

Development of Turbulent Diffusion Transfer Algorithms to Estimate Lake Tahoe Water Budget

NASA Astrophysics Data System (ADS)

Sahoo, G. B.; Schladow, S. G.; Reuter, J. E.

2012-12-01

The evaporative loss is a dominant component in the Lake Tahoe hydrologic budget because watershed area (813km2) is very small compared to the lake surface area (501 km2). The 5.5 m high dam built at the lake's only outlet, the Truckee River at Tahoe City can increase the lake's capacity by approximately 0.9185 km3. The lake serves as a flood protection for downstream areas and source of water supply for downstream cities, irrigation, hydropower, and instream environmental requirements. When the lake water level falls below the natural rim, cessation of flows from the lake cause problems for water supply, irrigation, and fishing. Therefore, it is important to develop algorithms to correctly estimate the lake hydrologic budget. We developed a turbulent diffusion transfer model and coupled to the dynamic lake model (DLM-WQ). We generated the stream flows and pollutants loadings of the streams using the US Environmental Protection Agency (USEPA) supported watershed model, Loading Simulation Program in C++ (LSPC). The bulk transfer coefficients were calibrated using correlation coefficient (R2) as the objective function. Sensitivity analysis was conducted for the meteorological inputs and model parameters. The DLM-WQ estimated lake water level and water temperatures were in agreement to those of measured records with R2 equal to 0.96 and 0.99, respectively for the period 1994 to 2008. The estimated average evaporation from the lake, stream inflow, precipitation over the lake, groundwater fluxes, and outflow from the lake during 1994 to 2008 were found to be 32.0%, 25.0%, 19.0%, 0.3%, and 11.7%, respectively.

75 FR 13232 - Safety Zone; Lake Mead Intake Construction, Lake Mead, Boulder City, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-19

...-AA00 Safety Zone; Lake Mead Intake Construction, Lake Mead, Boulder City, NV AGENCY: Coast Guard, DHS... waters of Lake Mead in support of the construction project for Lake Mead's Intake 3. This safety zone is... for the placement of an Intake Pipe from Lake Mead throughout 2010. This safety zone is necessary to...

Mixing and the dynamics of the deep chlorophyll maximum in Lake Tahoe

NASA Technical Reports Server (NTRS)

Abbott, M. R.; Denman, K. L.; Powell, T. M.; Richerson, P. J.; Richards, R. C.; Goldman, C. R.

1984-01-01

Chlorophyll-temperature profiles were measured across Lake Tahoe about every 10 days from April through July 1980. Analysis of the 123 profiles and associated productivity and nutrient data identified three important processes in the formation and dynamics of the deep chlorophyll maximum (DCM): turbulent diffusion, nutrient supply rate, and light availability. Seasonal variation in these three processes resulted in three regimes: a diffusion-dominated regime with a weak DCM, a variable-mixing regime with a pronounced, nutrient supply-dominated DCM, and a stable regime with a deep, moderate light availability-dominated DCM. The transition between the first two regimes occurred in about 10 days, the transition between the last two more gradually over about 3 weeks. The degree of spatial variability of the DCM was highest in the second regime and lowest in the third. These data indicate that the DCM in Lake Tahoe is constant in neither time nor space.

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

76 FR 2579 - Safety Zone; Lake Mead Intake Construction, Lake Mead, Boulder City, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-14

...-AA00 Safety Zone; Lake Mead Intake Construction, Lake Mead, Boulder City, NV AGENCY: Coast Guard, DHS... waters of Lake Mead in support of the construction project for Lake Mead's Intake 3 during the first 6... blasting operations for the placement of a water intake pipe in Lake Mead during the first 6 months of 2011...

Elytroderm disease in young, planted Jeffrey pine, South Lake Tahoe, California

Treesearch

Robert F. Scharpf; Robert V. Bega

1988-01-01

Little is known about Elytrodema disease (Elytroderma deformans [Weir] Darker) in seedlings or very young trees. Of 100, 2-0 Jeffrey pine (Pinus jeffreyi Grev. & Balf.) seedlings planted in the Taylor Creek area of South Lake Tahoe, about half survived from 1973 to 1987. During this period about two thirds of the surviving...

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.

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

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.

Estimating chlorophyll content and bathymetry of Lake Tahoe using AVIRIS data

NASA Technical Reports Server (NTRS)

Hamilton, Michael K.; Davis, Curtiss O.; Rhea, W. J.; Pilorz, Stuart H.; Carder, Kendall L.

1993-01-01

Data on chlorophyll content and bathymetry of Lake Tahoe obtained on August 9, 1990 by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) are compared to concurrent in situ surface and in-water measurements. Measured parameters included profiles of percent transmission of monochromatic light, stimulated chlorophyll fluorescence, photosynthetically available radiation, spectral upwelling and downwelling irradiance, and upwelling radiance. Several analyses were performed illustrating the utility of the AVIRIS over a dark water scene. Image-derived chlorophyll concentration compared extremely well with that measured with bottle samples. A bathymetry map of the shallow parts of the lake was constructed which compares favorably with published lake soundings.

South Lake Tahoe, California: Using Energy Data to Partner on Building Energy Efficiency Actions (City Energy: From Data to Decisions)

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

Strategic Priorities and Impact Analysis Team, Office of Strategic Programs

This fact sheet "South Lake Tahoe, California: Using Energy Data to Partner on Building Energy Efficiency Actions" explains how the City of South Lake Tahoe used data from the U.S. Department of Energy's Cities Leading through Energy Analysis and Planning (Cities-LEAP) and the State and Local Energy Data (SLED) programs to inform its city energy planning. It is one of ten fact sheets in the "City Energy: From Data to Decisions" series.

Improving erosion modeling on forest roads in the Lake Tahoe Basin: Small plot rainfall simulations to determine saturated hydraulic conductivity and interrill erodibility

Treesearch

N. S. Copeland; R. B. Foltz

2009-01-01

Lake Tahoe is renowned for its beauty and exceptionally clear water. The Tahoe basin economy is dependent upon the protection of this beauty and the continued availability of recreational opportunities in the area; however, scientists estimate that the continued increase in fine sediment and nutrient transport to the lake threatens to diminish this clarity in as little...

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...

ARkStorm@Tahoe: Stakeholder perspectives on vulnerabilities and preparedness for an extreme storm event in the greater Lake Tahoe, Reno, and Carson City region

USGS Publications Warehouse

Albano, Christine M.; Cox, Dale A.; Dettinger, Michael; Shaller, Kevin; Welborn, Toby L.; McCarthy, Maureen

2014-01-01

Atmospheric rivers (ARs) are strongly linked to extreme winter precipitation events in the Western U.S., accounting for 80 percent of extreme floods in the Sierra Nevada and surrounding lowlands. In 2010, the U.S. Geological Survey developed the ARkStorm extreme storm scenario for California to quantify risks from extreme winter storms and to allow stakeholders to better explore and mitigate potential impacts. To explore impacts on natural resources and communities in montane and adjacent environments, we downscaled the scenario to the greater Lake Tahoe, Reno and Carson City region of northern Nevada and California. This ArkStorm@Tahoe scenario was presented at six stakeholder meetings, each with a different geographic and subject matter focus. Discussions were facilitated by the ARkStorm@Tahoe team to identify social and ecological vulnerabilities to extreme winter storms, science and information needs, and proactive measures that might minimize impacts from this type of event. Information collected in these meetings was used to develop a tabletop emergency response exercise and set of recommendations for increasing resilience to extreme winter storm events in both Tahoe and the downstream communities of Northern Nevada.Over 300 individuals participated in ARkStorm@Tahoe stakeholder meetings and the emergency response exercise, including representatives from emergency response, natural resource and ecosystem management, health and human services, public utilities, and businesses. Interruption of transportation, communications, and lack of power and backup fuel supplies were identified as the most likely and primary points of failure across multiple sectors and geographies, as these interruptions have cascading effects on natural and human systems by impeding emergency response efforts. Other key issues that arose in discussions included contamination risks to water supplies and aquatic ecosystems, especially in the Tahoe Basin and Pyramid Lake, interagency

Fugitive dust emissions from paved road travel in the Lake Tahoe basin.

PubMed

Zhu, Dongzi; Kuhns, Hampden D; Brown, Scott; Gillies, John A; Etyemezian, Vicken; Gertler, Alan W

2009-10-01

The clarity of water in Lake Tahoe has declined substantially over the past 40 yr. Causes of the degradation include nitrogen and phosphorous fertilization of the lake waters and increasing amounts of inorganic fine sediment that can scatter light. Atmospheric deposition is a major source of fine sediment. A year-round monitoring study of road dust emissions around the lake was completed in 2007 using the Testing Re-entrained Aerosol Kinetic Emissions from Roads (TRAKER) system developed at the Desert Research Institute (DRI). Results of this study found that, compared with the summer season, road dust emissions increased by a factor of 5 in winter, on average, and about a factor of 10 when traction control material was applied to the roads after snow events. For winter and summer, road dust emission factors (grams coarse particulate matter [PM10] per vehicle kilometer traveled [g/vkt]) showed a decreasing trend with the travel speed of the road. The highest emission factors were observed on very low traffic volume roads on the west side of the lake. These roads were composed of either a 3/8-in. gravel material or had degraded asphalt. The principle factors influencing road dust emissions in the basin are season, vehicle speed (or road type), road condition, road grade, and proximity to other high-emitting roads. Combined with a traffic volume model, an analysis of the total emissions from the road sections surveyed indicated that urban areas (in particular South Lake Tahoe) had the highest emitting roads in the basin.

Vegetation management in sensitive areas of the Lake Tahoe Basin: A workshop to evaluate risks and advance existing strategies and practices [Independent review panel report

Treesearch

William Elliot; Wally Miller; Bruce Hartsough; Scott Stephens

2009-01-01

Elected officials, agency representatives and stakeholders representing many segments of the Lake Tahoe Basin community have all raised concerns over the limited progress in reducing excess vegetation biomass in Stream Environment Zones (SEZ) and on steep slopes (collectively referred to as sensitive areas) in the Lake Tahoe Basin. Limited access, the potential for...

Multi-Scale Simulations of Past and Future Projections of Hydrology in Lake Tahoe Basin, California-Nevada (Invited)

NASA Astrophysics Data System (ADS)

Niswonger, R. G.; Huntington, J. L.; Dettinger, M. D.; Rajagopal, S.; Gardner, M.; Morton, C. G.; Reeves, D. M.; Pohll, G. M.

2013-12-01

Water resources in the Tahoe basin are susceptible to long-term climate change and extreme events because it is a middle-altitude, snow-dominated basin that experiences large inter-annual climate variations. Lake Tahoe provides critical water supply for its basin and downstream populations, but changes in water supply are obscured by complex climatic and hydrologic gradients across the high relief, geologically complex basin. An integrated surface and groundwater model of the Lake Tahoe basin has been developed using GSFLOW to assess the effects of climate change and extreme events on surface and groundwater resources. Key hydrologic mechanisms are identified with this model that explains recent changes in water resources of the region. Critical vulnerabilities of regional water-supplies and hazards also were explored. Maintaining a balance between (a) accurate representation of spatial features (e.g., geology, streams, and topography) and hydrologic response (i.e., groundwater, stream, lake, and wetland flows and storages), and (b) computational efficiency, is a necessity for the desired model applications. Potential climatic influences on water resources are analyzed here in simulations of long-term water-availability and flood responses to selected 100-year climate-model projections. GSFLOW is also used to simulate a scenario depicting an especially extreme storm event that was constructed from a combination of two historical atmospheric-river storm events as part of the USGS MultiHazards Demonstration Project. Historical simulated groundwater levels, streamflow, wetlands, and lake levels compare well with measured values for a 30-year historical simulation period. Results are consistent for both small and large model grid cell sizes, due to the model's ability to represent water table altitude, streams, and other hydrologic features at the sub-grid scale. Simulated hydrologic responses are affected by climate change, where less groundwater resources will be

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…

Estimating Sediment Losses Generated from Highway Cut and Fill Slopes in the Lake Tahoe Basin

DOT National Transportation Integrated Search

2014-12-01

Lake Tahoes famed water clarity has gradually declined over the last 50 years, partially as a result of fine sediment particle (FSP, < 16 micrometers in diameter) contributions from urban stormwater. Of these urban sources, highway cut and fill sl...

33 CFR 165.T11-281 - Safety Zone; Lake Mead Intake Construction; Lake Mead, Boulder City, NV.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Safety Zone; Lake Mead Intake Construction; Lake Mead, Boulder City, NV. 165.T11-281 Section 165.T11-281 Navigation and Navigable Waters... Coast Guard District § 165.T11-281 Safety Zone; Lake Mead Intake Construction; Lake Mead, Boulder City...

The response of Lake Tahoe to climate change

USGS Publications Warehouse

Sahoo, G.B.; Schladow, S.G.; Reuter, J.E.; Coats, R.; Dettinger, M.; Riverson, J.; Wolfe, B.; Costa-Cabral, M.

2013-01-01

Meteorology is the driving force for lake internal heating, cooling, mixing, and circulation. Thus continued global warming will affect the lake thermal properties, water level, internal nutrient loading, nutrient cycling, food-web characteristics, fish-habitat, aquatic ecosystem, and other important features of lake limnology. Using a 1-D numerical model - the Lake Clarity Model (LCM) - together with the down-scaled climatic data of the two emissions scenarios (B1 and A2) of the Geophysical Fluid Dynamics Laboratory (GFDL) Global Circulation Model, we found that Lake Tahoe will likely cease to mix to the bottom after about 2060 for A2 scenario, with an annual mixing depth of less than 200 m as the most common value. Deep mixing, which currently occurs on average every 3-4 years, will (under the GFDL B1 scenario) occur only four times during 2061 to 2098. When the lake fails to completely mix, the bottom waters are not replenished with dissolved oxygen and eventually dissolved oxygen at these depths will be depleted to zero. When this occurs, soluble reactive phosphorus (SRP) and ammonium-nitrogen (both biostimulatory) are released from the deep sediments and contribute approximately 51 % and 14 % of the total SRP and dissolved inorganic nitrogen load, respectively. The lake model suggests that climate change will drive the lake surface level down below the natural rim after 2085 for the GFDL A2 but not the GFDL B1 scenario. The results indicate that continued climate changes could pose serious threats to the characteristics of the Lake that are most highly valued. Future water quality planning must take these results into account.

An integrated science plan for the Lake Tahoe basin: conceptual framework and research strategies

Treesearch

Zachary P. Hymanson; Michael W. Collopy

2010-01-01

An integrated science plan was developed to identify and refine contemporary science information needs for the Lake Tahoe basin ecosystem. The main objectives were to describe a conceptual framework for an integrated science program, and to develop research strategies addressing key uncertainties and information gaps that challenge government agencies in the theme...

Projections and downscaling of 21st century temperatures, precipitation, radiative fluxes and winds for the southwestern US, with focus on the Lake Tahoe basin

USGS Publications Warehouse

Dettinger, Michael D.

2013-01-01

Recent projections of global climate changes in response to increasing greenhouse-gas concentrations in the atmosphere include warming in the Southwestern US and, especially, in the vicinity of Lake Tahoe of from about +3°C to +6°C by end of century and changes in precipitation on the order of 5-10 % increases or (more commonly) decreases, depending on the climate model considered. Along with these basic changes, other climate variables like solar insolation, downwelling (longwave) radiant heat, and winds may change. Together these climate changes may result in changes in the hydrology of the Tahoe basin and potential changes in lake overturning and ecological regimes. Current climate projections, however, are generally spatially too coarse (with grid cells separated by 1 to 2° latitude and longitude) for direct use in assessments of the vulnerabilities of the much smaller Tahoe basin. Thus, daily temperatures, precipitation, winds, and downward radiation fluxes from selected global projections have been downscaled by a statistical method called the constructed-analogues method onto 10 to 12 km grids over the Southwest and especially over Lake Tahoe. Precipitation, solar insolation and winds over the Tahoe basin change only moderately (and with indeterminate signs) in the downscaled projections, whereas temperatures and downward longwave fluxes increase along with imposed increases in global greenhouse-gas concentrations.

HYDICE data from Lake Tahoe: comparison to coincident AVIRIS and in-situ measurements

NASA Astrophysics Data System (ADS)

Kappus, Mary E.; Davis, Curtiss O.; Rhea, W. J.

1996-11-01

Coordinated flights of two calibrated airborne imaging spectrometers, HYDICE and AVIRIS, were conducted on June 22, 1995 over Lake Tahoe. As part of HYDICE's first operational mission, one objective was to test the system performance over the dark homogeneous target provided by the clear deep waters of the lake. The high altitude and clear atmosphere makes Lake Tahoe a simpler test target than near-shore marine environments, where large aerosols complicate atmospheric correction and sediment runoff and high chlorophyll levels make interpretation of he data difficult. Calibrated data from both runoff and high chlorophyll levels make interpretation of the data difficult. Calibrated data from both sensors was provided in physical units of radiance. The atmospheric radiative transfer code, MODTRAN was used to remove the path radiance between the ground and sensor and the skylight reflected from the water surface. The resulting water-leaving spectrometer, and with values calculated form in-water properties using the HYDROLIGHT radiative transfer code. The agreement of the water-leaving radiance for the HYDICE data, the ground-truth spectral measurements, and the results of the radiative transfer code are excellent for wavelengths greater than 0.45 micrometers . The AVIRIS flight took place more than an hour closer to noon, which makes the radiance measurements not directly comparable. Comparisons to radiative transfer output for this later time indicate that the AVIRIS data is strongly by sun glint. Because water-leaving radiance is dependent upon the characteristics of the water, it can be analyzed for some of those properties. Using the CZCS algorithm based on the water-leaving radiance at two wavelengths, the chlorophyll content of Lake Tahoe was computed from the HYDICE and ground-truth data. Resulting values are slightly higher than measurements made two weeks earlier from water samples, indicating a growth in the phytoplankton population which is very plausible

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.

Forest changes since Euro-American settlement and ecosystem restoration in the Lake Tahoe Basin, USA

Treesearch

Alan H. Taylor

2007-01-01

Pre Euro-American settlement forest structure and fire regimes for Jeffrey pine-white fir, red fir-western white pine, and lodgepole pine forests were quantified using stumps from trees cut in the 19th century to establish a baseline reference for ecosystem management in the Lake Tahoe Basin. Contemporary forests varied in different ways compared...

Pile burning effects on soil water repellency, infiltration, and downslope water chemistry in the Lake Tahoe Basin, USA

Treesearch

Ken Hubbert; Matt Busse; Steven Overby; Carol Shestak; Ross Gerrard

2015-01-01

Thinning of conifers followed by pile burning has become a popular treatment to reduce fuel loads in the Lake Tahoe Basin. However, concern has been voiced about burning within or near riparian areas because of the potential effect on nutrient release and, ultimately, lake water quality. Our objective was to quantify the effects of pile burning on soil physical and...

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.

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.

Elytroderma disease reduces growth and vigor, increases mortality of Jeffrey pines at Lake Tahoe Basin, California

Treesearch

Robert R Scharpf; Robert V. Bega

1981-01-01

A disease of Jeffrey pines (Pinus jeffreyi Grev. and Balf.) at Lake Tahoe Basin, California, caused by Elytrodenna disease (Elytroderma deformans) was studied for 7 years after a severe outbreak ofthe fungus in 1971. Among 607 Jeffrey pines on six plots, about one-half were heavily infected and about one-half were moderately or lightly infected in 1971. No uninfected...

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

Long-Term Trends in Nutrient Concentrations and Fluxes in Streams Draining to Lake Tahoe, California

NASA Astrophysics Data System (ADS)

Domagalski, J. L.

2017-12-01

Lake Tahoe, situated in the rain shadow of the eastern Sierra Nevada at an elevation of 1,897 meters, has numerous small to medium sized tributaries that are sources of nutrients and fine sediment. The Tahoe watershed is relatively small and the surface area of the lake occupies about 38% of the total watershed area (1,313 km2). Each stream contributing water to the lake therefore also occupies a small watershed, mostly forested, with typical trees being Jeffrey, Ponderosa, or Sugar Pine and White Fir. Outflow from the lake contributes to downstream uses such as water supply and ecological resources. Only about 6% of the watershed is urbanized or residential land, and wastewater is exported to adjacent basins and not discharged to the lake as part of a plan to maintain water clarity. The lake's exceptional clarity has been diminishing due to phytoplankton and fine sediment, prompting development of management plans to improve water quality. Much of the annual discharge and flux of nutrients to the lake results from snowmelt in the spring and summer months, and climatic changes have begun to shift this melt to earlier time frames. Winter rains on urbanized land also contribute to nutrient loads. To understand the relative importance of land use, climate, and other factors affecting stream concentrations and fluxes, a Weighted Regression on Time Discharge and Season (WRTDS) model documented trends over a time frame of greater than 25 years. Ten streams have records of discharge, nutrient (NO3, NH3, OP, TP, TKN) and sediment data to complete this analysis. Both urbanized and non-urbanized locations generally show NO3 trending down in the 1980s. Some locations show initially decreasing orthophosphate trends, followed by small significant increases in concentration and fluxes starting around 2000 to 2005. Although no wastewater enters the streams, ammonia concentrations mimic those of orthophosphate, with initially negative trends in concentration and flux followed by

Response of visitors to the Rainbow Trail: an evaluation of an interpretive area in the Lake Tahoe Basin, California

Treesearch

Richard A. Kuehner; Gary H. Elsner

1978-01-01

Behavior of visitors on the Rainbow Trail, a Forest Service Interpretive Area in the Lake Tahoe Basin, California, was surveyed by observation and by interview. Some significant differences between trail visitors and other kinds of outdoor recreation enthusiasts were discovered. Enjoyment was high, and learning, while moderate, exceeded expectations. The Stream Profile...

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

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

Population biology of sugar pine (Pinus lambertiana Dougl.) with reference to historical disturbances in the Lake Tahoe Basin: implications for restoration

Treesearch

Patricia E. Maloney; Detlev R. Vogler; Andrew J. Eckert; Camille E. Jensen; David B. Neale

2011-01-01

Historical logging, fire suppression, and an invasive pathogen, Cronartium ribicola, the cause of white pine blister rust (WPBR), are assumed to have dramatically affected sugar pine (Pinus lambertiana) populations in the Lake Tahoe Basin. We examined population- and genetic-level consequences of these disturbances within 10...

Analysis of Atmospheric Nitrate Deposition in Lake Tahoe Using Multiple Oxygen Isotopes

NASA Astrophysics Data System (ADS)

McCabe, J. R.; Michalski, G. M.; Hernandez, L. P.; Thiemens, M. H.; Taylor, K.; Kendall, C.; Wankel, S. D.

2002-12-01

Lake Tahoe in the Sierra Nevada Mountain Range is world renown for its depth and water clarity bringing 2.2 million visitors per year resulting in annual revenue of \\1.6 billion from tourism. In past decades the lake has suffered from decreased water clarity (from 32 m plate depth to less than 20), which is believed to be largely the result of algae growth initiated by increased nutrient loading. Lake nutrients have also seen a shift from a nitrogen limited to a phosphorous limited system indicating a large increase in the flux of fixed nitrogen. Several sources of fixed nitrogen of have been suggested including surface runoff, septic tank seepage from ground water and deposition from the atmosphere. Bio-available nitrogen in the form of nitrate (NO_{3}$-) is a main component of this system. Recent studies have estimated that approximately 50% of the nitrogen input into the lake is of atmospheric origin (Allison et al. 2000). However, the impact and magnitude of atmospheric deposition is still one of the least understood aspects of the relationship between air and water quality in the Basin (TRPA Threshold Assessment 2002). The utility of stable isotopes as tracers of nitrate reservoirs has been shown in several studies (Bohlke et al. 1997, Kendall and McDonnell 1998, Durka et al. 1994). Stable nitrogen (δ15N) and oxygen (δ18O) isotopes have been implemented in a dual isotope approach to characterize the various nitrate sources to an ecosystem. While δ18O distinguishes between atmospheric and soil sources of nitrate, processes such as denitrification can enrich the residual nitrate in δ18O leaving a misleading atmospheric signature. The benefit of δ15N as a tracer for NO3- sources is the ability to differentiate natural soil, fertilizer, and animal or septic waste, which contain equivalent δ18O values. The recent implementation of multiple oxygen isotopes to measure Δ17O in nitrate has proven to be a more sensitive tracer of atmospheric deposition. The

Prescription Fire and Anion Retention in Tahoe Forest Soils

USDA-ARS?s Scientific Manuscript database

Prescribed burning is a possible option to reduce fire potential in the Lake Tahoe Basin (California and Nevada). However, subsequent nutrient loading to the lake is a major concern. The effect of residual ash on anion leaching, primarily O-PO4 and SO42-, was studied in both the field and laboratory...

75 FR 5115 - Temporary Concession Contract for Lake Mead National Recreation Area, AZ/NV

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-01

... National Recreation Area, AZ/NV AGENCY: National Park Service, Department of the Interior. ACTION: Notice of intention to award temporary concession contract for Lake Mead National Recreation Area. SUMMARY: Pursuant to 36 CFR 51.24, public notice is hereby given that the National Park Service intends to award a...

South Tahoe: A Model for Career Tech

ERIC Educational Resources Information Center

Kisel, James

2012-01-01

With the help of close to $30 million in grant monies from Career Technical Education (CTE) and Overcrowding Relief grants, and Joint-Use and High Performance grants, Lake Tahoe Unified School District and architect LPA, Inc., have already completed a CTE "Green" Construction and Transportation Academy, a new classroom building and the…

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)

78 FR 39599 - Safety Zone; Independence Day Fireworks, Kings Beach, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-02

... South Lake Tahoe, CA in approximate position 38[deg] 56'05'' N, 120[deg] 00'09'' W (NAD 83). From 9 a.m... off of Kings Beach, CA in approximate position 39[deg] 13'55'' N, 120[deg] 01'42'' W (NAD 83) where it... approximate position 39[deg] 13'55'' N, 120[deg] 01'42'' W (NAD 83) for the Independence Day Fireworks, Kings...

Surface- and ground-water characteristics in the Upper Truckee River and Trout Creek watersheds, South Lake Tahoe, California and Nevada, July-December 1996

USGS Publications Warehouse

Rowe, T.G.; Allander, Kip K.

2000-01-01

The Upper Truckee River and Trout Creek watersheds, South Lake Tahoe, California and Nevada, were studied from July to December 1996 to develop a better understanding of the relation between surface water and ground water. Base flows at 63 streamflow sites were measured in late September 1996 in the Upper Truckee River and Trout Creek watersheds. Most reaches of the main stem of the Upper Truckee River and Trout Creek had gaining or steady flows, with one losing reach in the mid-section of each stream. Twenty-seven of the streamflow sites measured in the Upper Truckee River watershed were on 14 tributaries to the main stem of the Upper Truckee River. Sixteen of the 40 streamflow sites measured in the Upper Truckee River watershed had no measurable flow. Streamflow in Upper Truckee River watershed ranged from 0 to 11.6 cubic feet per second (ft3/s). The discharge into Lake Tahoe from the Upper Truckee River was 11.6 ft3/s, of which, 40 percent of the flow was from ground-water discharge into the main stem, 40 percent was from tributary inflows, and the remaining 20 percent was the beginning flow. Gains from or losses to ground water along streams ranged from a 1.4 cubic feet per second per mile (ft3/s/mi) gain to a 0.5 ft3/s/mi loss along the main stem. Fourteen of the streamflow sites measured in the Trout Creek watershed were on eight tributaries to the main stem of Trout Creek. Of the 23 streamflow sites measured in the Trout Creek watershed, only one site had no flow. Flows in the Trout Creek watershed ranged from zero to 23.0 ft3/s. Discharge into Lake Tahoe from Trout Creek was 23.0 ft3/s, of which, about 5 percent of the flow was from ground-water discharge into the main stem, 75 percent was from tributary inflows, and the remaining 20 percent was the beginning flow. Ground-water seepage rates ranged from a 1.4 ft3/s/mi gain to a 0.9 ft3/s/mi loss along the main stem. Specific conductances measured during the seepage run in September 1996 increased in a

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

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

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

New insights into North America-Pacific Plate boundary deformation from Lake Tahoe, Salton Sea and southern Baja California

NASA Astrophysics Data System (ADS)

Brothers, Daniel Stephen

Five studies along the Pacific-North America (PA-NA) plate boundary offer new insights into continental margin processes, the development of the PA-NA tectonic margin and regional earthquake hazards. This research is based on the collection and analysis of several new marine geophysical and geological datasets. Two studies used seismic CHIRP surveys and sediment coring in Fallen Leaf Lake (FLL) and Lake Tahoe to constrain tectonic and geomorphic processes in the lakes, but also the slip-rate and earthquake history along the West Tahoe-Dollar Point Fault. CHIRP profiles image vertically offset and folded strata that record deformation associated with the most recent event (MRE). Radiocarbon dating of organic material extracted from piston cores constrain the age of the MRE to be between 4.1--4.5 k.y. B.P. Offset of Tioga aged glacial deposits yield a slip rate of 0.4--0.8 mm/yr. An ancillary study in FLL determined that submerged, in situ pine trees that date to between 900-1250 AD are related to a medieval megadrought in the Lake Tahoe Basin. The timing and severity of this event match medieval megadroughts observed in the western United States and in Europe. CHIRP profiles acquired in the Salton Sea, California provide new insights into the processes that control pull-apart basin development and earthquake hazards along the southernmost San Andreas Fault. Differential subsidence (>10 mm/yr) in the southern sea suggests the existence of northwest-dipping basin-bounding faults near the southern shoreline. In contrast to previous models, the rapid subsidence and fault architecture observed in the southern part of the sea are consistent with experimental models for pull-apart basins. Geophysical surveys imaged more than 15 ˜N15°E oriented faults, some of which have produced up to 10 events in the last 2-3 kyr. Potentially 2 of the last 5 events on the southern San Andreas Fault (SAF) were synchronous with rupture on offshore faults, but it appears that ruptures on

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)

Satellite Validation: A Project to Create a Data-Logging System to Monitor Lake Tahoe

NASA Technical Reports Server (NTRS)

Roy, Rudy A.

2005-01-01

Flying aboard the satellite Terra, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is an imaging instrument used to acquire detailed maps of Earth's surface temperature, elevation, emissivity, and reflectance. An automated site consisting of four buoys was established 6 years ago at Lake Tahoe for the validation of ASTERS thermal infrared data. Using Campbell CR23X Dataloggers, a replacement system to be deployed on a buoy was designed and constructed for the measurement of the lake's temperature profile, surrounding air temperature, humidity, wind direction and speed, net radiation, and surface skin temperature. Each Campbell Datalogger has been programmed to control, power, and monitor 14 different temperature sensors, a JPL-built radiometer, and an RM Young 32500 meteorological station. The logger communicates with the radiometer and meteorological station through a Campbell SDM-SIO4 RS232 serial interface, sending polling commands, and receiving filtered data back from the sensors. This data is then cataloged and sent back across a cellular modem network every hour to JPL. Each instrument is wired via a panel constructed with 18 individual plugs that allow for simple installation and expansion. Data sent back from the system are analyzed at JPL, where they are used to calibrate ASTER data.

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.

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.

77 FR 39670 - Endangered and Threatened Wildlife and Plants; 90-Day Finding on a Petition To List a Distinct...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-05

... by habitat loss due primarily to residential development and recreational encroachment (Big Wildlife... Great Basin ecosystem (Big Wildlife and NoBearHuntNV.org 2011, p. 13). The petition asserts that loss of... hair) from two American black bear populations: Lake Tahoe Basin, Nevada, and Yosemite National Park...

Early Pleistocene(?) pollen spectra from near Lake Tahoe, California

USGS Publications Warehouse

Adam, David P.

1973-01-01

Fossil pollen was recovered at Tahoe City, Calif., from beneath a 1.9-m.y.-old volcanic flow. Pollen counts of four fossil samples are compared with soil-surface pollen samples from the Sierra Nevada. The presence of Picea (spruce) pollen in the fossil samples suggests that summer drought conditions in the central Sierra Nevada were less severe prior to 1.9 m.y. ago than they are now.

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

Comparison of microbial communities in Lake Tahoe surface sample with Tonga Trench water column samples using High Pressure Liquid Chromatography - Electrospray Ionization - Mass Spectroscopy (HPLC - ESI - MS) and Global Natural Products Social Molecular Network (GNPS)

NASA Astrophysics Data System (ADS)

Belmonte, M. A.

2015-12-01

Intact polar lipids (IPLs) are lipids composed of a head group, a glycerol, and a fatty acid chain that make up the lipid bilayer of cell membranes in living cells; and the varying head groups can be indicative of the type of microbes present in the environment (Van Mooy 2010). So by distinguishing and identifying the IPL distribution in an environment one can make inferences about the microbial communities in the said environment. In this study, we used High Pressure Liquid Chromatography-Electrospray Ionization- Mass Spectroscopy (HPLC-ESI-MS) and Global Natural Products Social Molecular Networking (GNPS) to compare the IPL distributions of two oligotrophic environments: surface waters of Lake Tahoe in the Sierra Nevada Mountains, and the water column of the Tonga Trench in the South Pacific. We hypothesized that the similar nutrient dynamics of the two oligotrophic environments would result in similar eukaryotic and prokaryotic communities, which would be reflected in the IPL composition of suspended particulate organic matter (POM). For simplicity we focused on the classes of IPLs most commonly observed in the marine environment: phosphotidylglycerol (PG), phosphotidylethanolamine (PE), diacylglyceryl-trimethyl-homoserine (DGTS), diacylglyceryl-hydroxymethyl-trimethylalanine (DGTA), sulfoquinovosyldiacylglycerol (SQDG), monoglycosyldiacylglycerol (MGDG) and diglycosyldiacylglycerol (DGDG). Our results showed that all of the marine IPLs of interest were present in Lake Tahoe which confirms that there are many of the same microbial communities in the fresh waters of Lake Tahoe and the salt waters Tonga Trench.

75 FR 35652 - Safety Zone; Northern California Annual Fireworks Events, Fourth of July Fireworks, South Lake...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-23

... Zone; Northern California Annual Fireworks Events, Fourth of July Fireworks, South Lake Tahoe Gaming... will enforce Lights on the Lake Fireworks Display safety zone for South Lake Tahoe, from 8:30 a.m. on... the Lake Fireworks in 33 CFR 165.1191 on July 4, 2010, from 8:30 a.m. on July 1, 2010 through 10 p.m...

76 FR 37650 - Safety Zone; Northern California Annual Fireworks Events, Fourth of July Fireworks, South Lake...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-28

... Zone; Northern California Annual Fireworks Events, Fourth of July Fireworks, South Lake Tahoe Gaming... will enforce the safety zone for the annual Fourth of July Fireworks, South Lake Tahoe Gaming Alliance (Lights on the Lake Fireworks Display). This action is necessary to control vessel traffic and to ensure...

2. View of switchback as it emerges to left of ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. View of switchback as it emerges to left of photograph. Skunk Harbor Road leaves the railroad grade at this point, looking southwest. 2400' from beginning of road 15N67. - Slaughterhouse Canyon Railroad Grade, South of State Highway 28 on East shore of Lake Tahoe, Carson City, Carson City, NV

A hydrodynamics-based approach to evaluating the risk of waterborne pathogens entering drinking water intakes in a large, stratified lake.

PubMed

Hoyer, Andrea B; Schladow, S Geoffrey; Rueda, Francisco J

2015-10-15

Pathogen contamination of drinking water lakes and reservoirs is a severe threat to human health worldwide. A major source of pathogens in surface sources of drinking waters is from body-contact recreation in the water body. However, dispersion pathways of human waterborne pathogens from recreational beaches, where body-contact recreation is known to occur to drinking water intakes, and the associated risk of pathogens entering the drinking water supply remain largely undocumented. A high spatial resolution, three-dimensional hydrodynamic and particle tracking modeling approach has been developed to analyze the risk and mechanisms presented by pathogen dispersion. The pathogen model represents the processes of particle release, transport and survival. Here survival is a function of both water temperature and cumulative exposure to ultraviolet (UV) radiation. Pathogen transport is simulated using a novel and computationally efficient technique of tracking particle trajectories backwards, from a drinking water intake toward their source areas. The model has been applied to a large, alpine lake - Lake Tahoe, CA-NV (USA). The dispersion model results reveal that for this particular lake (1) the risk of human waterborne pathogens to enter drinking water intakes is low, but significant; (2) this risk is strongly related to the depth of the thermocline in relation to the depth of the intake; (3) the risk increases with the seasonal deepening of the surface mixed layer; and (4) the risk increases at night when the surface mixed layer deepens through convective mixing and inactivation by UV radiation is eliminated. While these risk factors will quantitatively vary in different lakes, these same mechanisms will govern the process of transport of pathogens. Copyright © 2015 Elsevier Ltd. All rights reserved.

76 FR 67533 - Environmental Impact Statement: Cities of South Lake Tahoe, CA and Stateline, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-01

... (LRWQCB) regulations and requirements, while enhancing the community and tourism experience; and (3... Stateline/Ski Run Community Plan Alternatives under consideration include (1) Taking no action; (2) a Build...

Leachate Geochemical Results for Ash Samples from the June 2007 Angora Wildfire Near Lake Tahoe in Northern California

USGS Publications Warehouse

Hageman, Philip L.; Plumlee, Geoffrey S.; Martin, Deborah A.; Hoefen, Todd M.; Adams, Monique; Lamothe, Paul J.; Todorov, Todor I.; Anthony, Michael W.

2008-01-01

This report releases leachate geochemical data for ash samples produced by the Angora wildfire that burned from June 24 to July 2, 2007, near Lake Tahoe in northern California. The leaching studies are part of a larger interdisciplinary study whose goal is to identify geochemical characteristics and properties of the ash that may adversely affect human health, water quality, air quality, animal habitat, endangered species, debris flows, and flooding hazards. The leaching study helps characterize and understand the interactions that occur when the ash comes in contact with rain or snowmelt, and helps identify the constituents that may be mobilized as run-off from these materials. Similar leaching studies were conducted on ash and burned soils from the October 2007 southern California wildfires (Hageman and others, 2008; Plumlee and others, 2007).

The impact of lake level variation on seismicity around XianNvShan fault in the Three Gorge area

NASA Astrophysics Data System (ADS)

Liao, W.; Li, J.; Zhang, L.

2017-12-01

Since the impounding of Three Gorge Project in 2003,more than 10000 earthquakes have been recorded by the digital telemetry seismic network. Most of them occurred around the GaoQiao fault and the Northern segment of XianNvShan fault . In March 2014, the M4.3 and M4.7 earthquake happened in the northern segment of Xiannvshshan fault .In order to study the relationship between the seismicity around the XianNvShan fault and the lake level variation, we had been deployed 5 temporal seismic stations in this area from 2015 to 2016. More than 3000 earthquakes recorded during the time of temporal seismic monitoring are located by hypo-center of by waveform cross-correlation and double-difference method. The depth of most earthquakes is from 5 to 7 km.but it is obvious that the variation of depth is relate to the fluctuation of water level.

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...

Nutrient concentrations in Upper and Lower Echo, Fallen Leaf, Spooner, and Marlette Lakes and associated outlet streams, California and Nevada, 2002-03

USGS Publications Warehouse

Lico, Michael S.

2004-01-01

Five lakes and their outlet streams in the Lake Tahoe Basin were sampled for nutrients during 2002-03. The lakes and streams sampled included Upper Echo, Lower Echo, Fallen Leaf, Spooner, and Marlette Lakes and Echo, Taylor, and Marlette Creeks. Water samples were collected to determine seasonal and spatial concentrations of dissolved nitrite plus nitrate, dissolved ammonia, total Kjeldahl nitrogen, dissolved orthophosphate, total phosphorus, and total bioreactive iron. These data will be used by Tahoe Regional Planning Agency in revising threshold values for waters within the Lake Tahoe Basin. Standard U.S. Geological Survey methods of sample collection and analysis were used and are detailed herein. Data collected during this study and summary statistics are presented in graphical and tabular form.

Future Wildfire and Managed Fire Interactions in the Lake Tahoe Basin

NASA Astrophysics Data System (ADS)

Scheller, R.; Kretchun, A.

2017-12-01

Managing large forested landscape in the context of a changing climate and altered disturbance regimes presents new challenges and require integrated assessments of forest disturbance, management, succession, and the carbon cycle. Successful management under these circumstances will require information about trade-offs among multiple objectives and opportunities for spatially optimized landscape-scale management. Improved information about the effects of climate on forest communities, disturbance feedbacks, and the effectiveness of mitigation strategies enables actionable options for landscape managers. We evaluated the effects of fire suppression, wildfires, and forest fuel (thinning) treatments on the long-term carbon storage potential for Lake Tahoe Basin (LTB) forests under various climate futures. We simulated management scenarios that encompass fuel treatments across the larger landscape, beyond the Wildland Urban Interface. We improved upon current fire modeling under climate change via an integrated fire modeling module that, a) explicitly captures the influence of climate, fuels, topography, active fire management (e.g., fire suppression), and fuel treatments, and b) can be parameterized from available data, e.g., remote sensing, field reporting, fire databases, expert opinion. These improvements increase geographic flexibility and decrease reliance on broad historical fire regime statistics - imperfect targets for a no analog future and require minimal parameterization and calibration. We assessed the interactions among fuel treatments, prescribe fire, fire suppression, and stochastically recurring wildfires. Predicted changes in climate and ignition patterns in response to future climatic conditions, vegetation dynamics, and fuel treatments indicate larger potential long-term effects on C emissions, forest structure, and forest composition than prior studies.

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

Drastic lake level changes of Lake Van (eastern Turkey) during the past ca. 600 ka: climatic, volcanic and tectonic control

NASA Astrophysics Data System (ADS)

Cukur, D.; Krastel, S.; Schmincke, H.; Sumita, M.; Tomonaga, Y.; Damci, E.

2013-12-01

Lake Van is the largest soda lake in the world with a present surface of 3,574 km2 and a maximum water depth of 450 m. Sedimentary deposits in the lake preserve one of the most complete record of continental climate in the Middle East since the Middle Pleistocene. We studied these deposits to characterize the evolution of the lake level and its possible relationships with changes in climate, volcanic, and regional tectonics since the formation of the lake ca. 600 ka ago. Changes in lake level were determined based on high-resolution seismic reflection profiles showing erosional surfaces, changes in stratal geometries such as downward shifts in coastal onlap, and recognition of distinctive stratigraphic features such as prograding delta clinoforms. Our results show that Lake Van has undergone drastic changes in surface elevation by as much as 600 meters over the past ca. 600 ka. Five major lowstands occurred at ca. ~600 ka, ca. 365-340 ka, ca 290-230 ka; ca. 150-130 ka; and ca. 30-14 ka. During a first period (A) (ca. 600-ca 230 ka) lake levels changed drastically by hundreds of m but at longer time intervals between low and high stands. Changes occurred more frequently but mostly by a few tens of m during the past ca. 230 ka years where we can distinguish a first period (B1) of stepwise transgressions between ca. 230 and 150 ka followed by a short regression between ca. 150 and 130 ka. Lake level rose stepwise again during period B2 lasting until ca 30 ka. During the past 30 ka a regression and a final transgression each lasted ca. 15 ka years. The major lowstand periods in Lake Van occurred during glacial periods, arguing for a climatic control of these lake-level fluctuations (i.e., significantly reduced precipitation leading to lake level low stands). Although climate forcing may have been the dominant cause for the drastic lake level changes of Lake Van, volcanic and tectonic forcing factors are also invoked. For example, the number of distinct tephra layers

The Control of an Invasive Bivalve, Corbicula fluminea, Using Gas Impermeable Benthic Barriers in a Large Natural Lake

NASA Astrophysics Data System (ADS)

Wittmann, Marion E.; Chandra, Sudeep; Reuter, John E.; Schladow, S. Geoffrey; Allen, Brant C.; Webb, Katie J.

2012-06-01

Anoxia can restrict species establishment in aquatic systems and the artificial promotion of these conditions can provide an effective control strategy for invasive molluscs. Low abundances (2-20 m-2) of the nonnative bivalve, Asian clam ( Corbicula fluminea), were first recorded in Lake Tahoe, CA-NV in 2002 and by 2010 nuisance-level population densities (>10,000 m-2) were observed. A non-chemical control method using gas impermeable benthic barriers to reduce dissolved oxygen (DO) concentrations available to C. fluminea was tested in this ultra-oligotrophic natural lake. In 2009, the impact of ethylene propylene diene monomer (EPDM) sheets (9 m2, n = 6) on C. fluminea beds was tested on 1-7 day intervals over a 56 day period (August-September). At an average water temperature of 18 °C, DO concentrations under these small barriers were reduced to zero after 72 h resulting in 100 % C. fluminea mortality after 28 days. In 2010, a large EPDM barrier (1,950 m2) was applied to C. fluminea populations for 120 days (July-November). C. fluminea abundances were reduced over 98 % after barrier removal, and remained significantly reduced (>90 %) 1 year later. Non-target benthic macroinvertebrate abundances were also reduced, with variable taxon-specific recolonization rates. High C. fluminea abundance under anoxic conditions increased the release of ammonium and soluble reactive phosphorus from the sediment substrate; but levels of unionized ammonia were low at 0.004-0.005 mg L-1. Prolonged exposure to anoxia using benthic barriers can provide an effective short term control strategy for C. fluminea.

The control of an invasive bivalve, Corbicula fluminea, using gas impermeable benthic barriers in a large natural lake.

PubMed

Wittmann, Marion E; Chandra, Sudeep; Reuter, John E; Schladow, S Geoffrey; Allen, Brant C; Webb, Katie J

2012-06-01

Anoxia can restrict species establishment in aquatic systems and the artificial promotion of these conditions can provide an effective control strategy for invasive molluscs. Low abundances (2-20 m(-2)) of the nonnative bivalve, Asian clam (Corbicula fluminea), were first recorded in Lake Tahoe, CA-NV in 2002 and by 2010 nuisance-level population densities (>10,000 m(-2)) were observed. A non-chemical control method using gas impermeable benthic barriers to reduce dissolved oxygen (DO) concentrations available to C. fluminea was tested in this ultra-oligotrophic natural lake. In 2009, the impact of ethylene propylene diene monomer (EPDM) sheets (9 m(2), n = 6) on C. fluminea beds was tested on 1-7 day intervals over a 56 day period (August-September). At an average water temperature of 18 °C, DO concentrations under these small barriers were reduced to zero after 72 h resulting in 100 % C. fluminea mortality after 28 days. In 2010, a large EPDM barrier (1,950 m(2)) was applied to C. fluminea populations for 120 days (July-November). C. fluminea abundances were reduced over 98 % after barrier removal, and remained significantly reduced (>90 %) 1 year later. Non-target benthic macroinvertebrate abundances were also reduced, with variable taxon-specific recolonization rates. High C. fluminea abundance under anoxic conditions increased the release of ammonium and soluble reactive phosphorus from the sediment substrate; but levels of unionized ammonia were low at 0.004-0.005 mg L(-1). Prolonged exposure to anoxia using benthic barriers can provide an effective short term control strategy for C. fluminea.

A reverse genetics system for the Great Lakes strain of viral hemorrhagic septicemia virus: the NV gene is required for pathogenicity

USGS Publications Warehouse

Ammayappan, Arun; Kurath, Gael; Thompson, Tarin M.; Vakharia, Vikram N.

2011-01-01

Viral hemorrhagic septicemia virus (VHSV), belonging to the genus Novirhabdovirus in the family of Rhabdoviridae, causes a highly contagious disease of fresh and saltwater fish worldwide. Recently, a novel genotype of VHSV, designated IVb, has invaded the Great Lakes in North America, causing large-scale epidemics in wild fish. An efficient reverse genetics system was developed to generate a recombinant VHSV of genotype IVb from cloned cDNA. The recombinant VHSV (rVHSV) was comparable to the parental wild-type strain both in vitro and in vivo, causing high mortality in yellow perch (Perca flavescens). A modified recombinant VHSV was generated in which the NV gene was substituted with an enhanced green fluorescent protein gene (rVHSV-ΔNV-EGFP), and another recombinant was made by inserting the EGFP gene into the full-length viral clone between the P and M genes (rVHSV-EGFP). The in vitro replication kinetics of rVHSV-EGFP was similar to rVHSV; however, the rVHSV-ΔNV-EGFP grew 2 logs lower. In yellow perch challenges, wtVHSV and rVHSV induced 82-100% cumulative per cent mortality (CPM), respectively, whereas rVHSV-EGFP produced 62% CPM and rVHSV-ΔNV-EGFP caused only 15% CPM. No reversion of mutation was detected in the recovered viruses and the recombinant viruses stably maintained the foreign gene after several passages. These results indicate that the NV gene of VHSV is not essential for viral replication in vitro and in vivo, but it plays an important role in viral replication efficiency and pathogenicity. This system will facilitate studies of VHSV replication, virulence, and production of viral vectored vaccines.

Cyst acquisition rate for Giardia lamblia in backcountry travelers to Desolation Wilderness, Lake Tahoe

USGS Publications Warehouse

Zell, S.C.; Sorenson, S.K.

1993-01-01

The objective of this study was to determine the incidence of Giardia lamblia acquisition in back-country travelers to a wilderness area, provide longitudinal follow-up on the incidence of symptomatic gastrointestinal illness and relate such information to concentrations of Giardia cysts in water samples from a high-use area. A prospective cohort non-interventional study of 41 healthy adult backcountry travelers from age 19 to 71 years in Desolation Wilderness, Lake Tahoe Basin was carried out. The incidence of Giardia cyst acquisition in backcountry travelers was only 5.7% (95% CI 0.17–20.2%). Mild, self-limiting gastrointestinal illness occurred in 16.7% of subjects (95% CI 4.9%–34.50%), none of whom demonstrated G. lamblia infection. Water sampling from three popular stream sites revealed cyst contamination to be generally at low levels with cyst concentrations in the single digit range for every 100 gallons filtered. G. lamblia contamination of water occurs, but at low levels. Acquisition of this parasite may be infrequent in backcountry recreationalists. Symptomatic gastrointestinal illness following wilderness travel can be due to other etiologies. Our findings may not be representative of all wilderness areas, but suggest that in the absence of documented G. lamblia infection, persons symptomatic following travel may suffer a self-limiting gastrointestinal illness. In such circumstances, empiric therapy for giardiasis is tempting but difficult to justify.

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

78 FR 63868 - Amendment of Restricted Area R-2515; Muroc Lake, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-25

...-0802; Airspace Docket No. 13-AWP-7] RIN 2120-AA66 Amendment of Restricted Area R-2515; Muroc Lake, CA... using agency name for Restricted Area R-2515 Muroc Lake, CA, to read ``Commander, 412th Test Wing (412... using agency name for Restricted Area R-2515 Muroc Lake, CA, from ``Commander Air Force Flight Test...

75 FR 45149 - Announcement of Funding Awards for Healthy Homes and Lead Hazard Control Grant Programs for...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-02

... announced in a Federal Register notice published on May 22, 2009 for Lead Based Paint Hazard Control and... for the Lead Based Paint Hazard Control Grant Program under the Consolidated Appropriations Act, 2009... Tahoe, 1901 Airport Road, Suite 107, South Lake Tahoe, CA 96150, $1,500,000; State of Connecticut...

The Role of Trans Tensional Structures and Lake Mead Reservoir in Groundwater Flow in Black Canyon, Lake Mead National Recreation Area, NV-AZ

NASA Astrophysics Data System (ADS)

Justet, L.; Beard, S.

2010-12-01

Hot springs and seeps discharging into Black Canyon (BC) along the Colorado River in north Colorado River Valley (CRV) support endemic riparian ecosystems in the Lake Mead National Recreation Area. Increases in groundwater development in southern NV and northwestern AZ may impact spring discharge. Sources of spring discharge in BC were evaluated using geochemical methods. Kinematic analysis and geologic mapping of structures associated with BC springs were used to evaluate structural controls on groundwater flow in BC. Geochemical analysis indicates groundwater discharge near Hoover Dam (HD) and along the faulted edge of the Boulder City Pluton is derived from Lake Mead, high δ87Sr Proterozoic or Tertiary crystalline rock and, possibly, Tertiary sedimentary rock. Reducing conditions indicated by 234U/238U and δ34S concentrations suggest the groundwater is confined and/or derived from greater depths while carbon isotopes indicate the groundwater is old. Lighter δD and δO-18, modern tritium concentrations, post-Dam U disequilibrium ages, and occurrence of anthropogenic perchlorate support the presence of a young Lake Mead component. South of the pluton, the Lake Mead component is absent. More oxidizing conditions in this part of BC, indicated by the U and S isotope concentrations, suggest the groundwater is less confined and/or derived from shallower depths compared to groundwater discharging near HD. Older apparent groundwater ages and heavier δD and δO-18 values south of the pluton indicate slower flow paths from a lower elevation or latitude source. Clarifying the nature of groundwater flow in eastern NV, the analyses indicate that hydraulic connection between the regional carbonate aquifer and BC is unlikely. Instead, the data indicate sources of BC springs are derived relatively locally in CRV and, possibly, south Lake Mead Valley. Results of the geologic and kinematic analyses indicate faults that formed from the interaction of E-W extension related to

In-flight validation and recovery of water surface temperature with Landsat-5 thermal infrared data using an automated high-altitude lake validation site at Lake Tahoe

USGS Publications Warehouse

Hook, S.J.; Chander, G.; Barsi, J.A.; Alley, R.E.; Abtahi, A.; Palluconi, Frank Don; Markham, B.L.; Richards, R.C.; Schladow, S.G.; Helder, D.L.

2004-01-01

The absolute radiometric accuracy of the thermal infrared band (B6) of the Thematic Mapper (TM) instrument on the Landsat-5 (L5) satellite was assessed over a period of approximately four years using data from the Lake Tahoe automated validation site (California-Nevada). The Lake Tahoe site was established in July 1999, and measurements of the skin and bulk temperature have been made approximately every 2 min from four permanently moored buoys since mid-1999. Assessment involved using a radiative transfer model to propagate surface skin temperature measurements made at the time of the L5 overpass to predict the at-sensor radiance. The predicted radiance was then convolved with the L5B6 system response function to obtain the predicted L5B6 radiance, which was then compared with the radiance measured by L5B6. Twenty-four cloud-free scenes acquired between 1999 and 2003 were used in the analysis with scene temperatures ranging between 4/spl deg/C and 22/spl deg/C. The results indicate L5B6 had a radiance bias of 2.5% (1.6/spl deg/C) in late 1999, which gradually decreased to 0.8% (0.5/spl deg/C) in mid-2002. Since that time, the bias has remained positive (predicted minus measured) and between 0.3% (0.2/spl deg/C) and 1.4% (0.9/spl deg/C). The cause for the cold bias (L5 radiances are lower than expected) is unresolved, but likely related to changes in instrument temperature associated with changes in instrument usage. The in situ data were then used to develop algorithms to recover the skin and bulk temperature of the water by regressing the L5B6 radiance and the National Center for Environmental Prediction (NCEP) total column water data to either the skin or bulk temperature. Use of the NCEP data provides an alternative approach to the split-window approach used with instruments that have two thermal infrared bands. The results indicate the surface skin and bulk temperature can be recovered with a standard error of 0.6/spl deg/C. This error is larger than errors

75 FR 22100 - Nevada County and Placer County, CA, Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-27

... the meeting is to discuss issues relating to implementing the Secure Rural Schools and Community Self... Title II funds benefiting National Forest System lands on the Humboldt-Toiyabe, Eldorado, Lake Tahoe...

Map Showing Limits of Tahoe Glaciation in Sequoia and Kings Canyon National Parks, California

USGS Publications Warehouse

Moore, James Gregory; Mack, Gregory S.

2008-01-01

The latest periods of extensive ice cover in the Sierra Nevada include the Tahoe glaciation followed by the Tioga glaciation, and evidence for these ice ages is widespread in the Sequoia and Kings Canyon National Parks area. However, the timing of the advances and retreats of the glaciers during the periods of glaciation continues to be a matter of debate. A compilation of existing work (Clark and others, 2003) defines the Tioga glaciation at 14-25 thousand years ago and splits the Tahoe glaciation into two stages that range from 42-50 and 140-200 thousand years ago. The extent of the Tahoe ice mass shown in the map area is considered to represent the younger Tahoe stage, 42-50 thousand years ago. Evidence of glaciations older than the Tahoe is limited in the southern Sierra Nevada. After the Tioga glaciation, only minor events with considerably less ice cover occurred. The Tioga glaciation was slightly less extensive than the Tahoe glaciation, and each covered about half of the area of Sequoia and Kings Canyon National Parks. The Tahoe glaciers extended 500-1,000 ft lower and 0.5-1.2 mi farther down valleys. Evidence for the Tahoe glacial limits is not as robust as that for Tioga, but the extent of the Tahoe ice is mapped because it covered a larger area and the ice did leave prominent moraines (piles of sediment and boulders deposited by glaciers as they melted at their margins) lower on the east front of the range. Current Sierra redwood (Sequoiadendron giganteum) groves occur in a belt on the west side of the Sierra Nevada, generally west of the area of Tahoe glaciation.

Chemistry of runoff and shallow ground water at the Cattlemans Detention basin site, South Lake Tahoe, California, August 2000-November 2001

USGS Publications Warehouse

Prudic, David E.; Sager, Sienna J.; Wood, James L.; Henkelman, Katherine K.; Caskey, Rachel M.

2005-01-01

A study at the Cattlemans detention basin site began in November 2000. The site is adjacent to Cold Creek in South Lake Tahoe, California. The purpose of the study is to evaluate the effects of the detention basin on ground-water discharge and changes in nutrient loads to Cold Creek, a tributary to Trout Creek and Lake Tahoe. The study is being done in cooperation with the Tahoe Engineering Division of the El Dorado County Department of Transportation. This report summarizes data collected prior to and during construction of the detention basin and includes: (1) nutrient and total suspended solid concentrations of urban runoff; (2) distribution of unconsolidated deposits; (3) direction of ground-water flow; and (4) chemistry of shallow ground water and Cold Creek. Unconsolidated deposits in the area of the detention basin were categorized into three classes: fill material consisting of a red-brown loamy sand with some gravel and an occasional cobble that was placed on top of the meadow; meadow deposits consisting of gray silt and sand with stringers of coarse sand and fine gravel; and a deeper brown to yellow-brown sand and gravel with lenses of silt and sand. Prior to construction of the detention basin, ground water flowed west-northwest across the area of the detention basin toward Cold Creek. The direction of ground-water flow did not change during construction of the detention basin. Median concentrations of dissolved iron and chloride were 500 and 30 times higher, respectively, in ground water from the meadow deposits than dissolved concentrations in Cold Creek. Median concentration of sulfate in ground water from the meadow deposits was 0.4 milligrams per liter and dissolved oxygen was below the detection level of 0.3 milligrams per liter. The relatively high concentrations of iron and the lack of sulfate in the shallow ground water likely are caused by chemical reactions and biological microbial oxidation of organic matter in the unconsolidated deposits

Lake Level Variation in Small Lakes: Not a Clear Picture

NASA Astrophysics Data System (ADS)

Starratt, S.

2017-12-01

Lake level is a useful tool for identifying regional changes in precipitation and evaporation. Due to the volume of water in large lakes, they may only record large-scale changes in water balance, while smaller lakes may record more subtle variations. However, the record of water level in small lakes is affected by a number of factors including elevation, bathymetry, nutrient load, and aquatic macrophyte abundance. The latest Quaternary diatom records from three small lakes with areas of <10 ha (Hobart Lake, OR, 1458 masl; Swamp Lake, CA, 1554 masl; Favre Lake, NV, 2899 masl) and a larger lake (Medicine Lake, CA, 2036 masl, 154 ha) were compared in this study. All the lakes have a deep central basin (>10 m) surrounded by a shallow (1-2 m) shelf. Changes in the abundance of diatoms representing different life habits (benthic, tychoplanktic, planktic) were used to identify lake level variation. Benthic taxa dominate the assemblage when only the central basin is occupied. As the shallow shelf is flooded, the abundance of tychoplanktic taxa increases. Planktic taxa increase with the establishment of stratification. Favre Lake presents the clearest indication of initial lake level rise (7600-5750 cal yr BP) and intermittent flooding of the shelf for the remainder of the record. Stratification appears to become established only in the last few hundred years. Higher nutrient levels in the early part of the Hobart Lake record lead to a nearly monotypic planktic assemblage which is replaced by a tychoplanktic-dominated assemblage as the lake floods the shelf at about 3500 cal yr BP. The last 500 years is dominated by benthic taxa associated with aquatic macrophytes. The consistent presence of planktic taxa in the Swamp Lake record suggests that the lake was stratified during most of its history, although slight variations in the relative abundances of planktic and tychoplanktic groups occur. The Medicine Lake record shows a gradual increase in planktic species between 11

CALL FOR ABSTRACTS - PIT LAKES 2004

EPA Science Inventory

This call for abstracts is for the 11/16-18/2004 Pit Lakes 2004 meeting held in Reno, NV. This conference will provide a forum for the exchange of scientific information on current domestic and international pit lake approaches, including pit lakes from arid and wet regions throu...

The no-project alternative analysis: An early product of the Tahoe Decision Support System

USGS Publications Warehouse

Halsing, David L.; Hessenflow, Mark L.; Wein, Anne

2005-01-01

We report on the development of a No-project alternative analysis (NPAA) or “business as usual” scenario with respect to a 20-year projection of 21 indicators of environmental and socioeconomic conditions in the Lake Tahoe Basin for the Tahoe Regional Planning Agency (TRPA). Our effort was inspired by earlier work that investigated the tradeoffs between an environmental and an economic objective. The NPAA study has implications for a longer term goal of building a Tahoe Decision Support System (TDSS) to assist the TRPA and other Basin agencies in assessing the outcomes of management strategies. The NPAA assumes no major deviations from current management practices or from recent environmental or societal trends and planned Environmental Improvement Program (EIP) projects. Quantitative “scenario generation” tools were constructed to simulate site-specific land uses, various population categories, and associated vehicle miles traveled. Projections of each indicator’s attainment status were made by building visual conceptual models of the relevant natural and social processes, extrapolating trends, and using available models, research, and expert opinion. We present results of the NPAA, projected indicator status, key factors affecting the indicators, indicator functionality, and knowledge gaps. One important result is that current management practices may slow the loss or degradation of environmental qualities but not halt or reverse it. Our analysis also predicts an increase in recreation and commuting into and within the basin, primarily in private vehicles. Private vehicles, which are a critical mechanism by which the Basin population affects the surrounding environment, are a key determinant of air-quality indicators, a source of particulate matter affecting Secchi depth, a source of noise, and a factor in recreational and scenic quality, largely owing to congestion. Key uncertainties in the NPAA include climate change, EIP project effectiveness, and

Distribution and Fate of Black Carbon Nanoparticles from Regional Urban Pollution and Wildfire at a Large Subalpine Lake in the Western United States

NASA Astrophysics Data System (ADS)

Bisiaux, M. M.; Heyvaert, A. C.; Edwards, R.

2012-04-01

Emitted to the atmosphere through fire and fossil fuel combustion, refractory black carbon nanoparticles (rBC) impact human health, climate, atmospheric chemistry, and the carbon cycle. Eventually these particles enter aquatic environments, where their distribution, fate and association with other pollutants are still poorly characterized. This study presents results from an evaluation of rBC in the waters of oligotrophic Lake Tahoe and its watershed in the western United States. The study period included a large wildfire within the Tahoe basin, seasonal snowmelt, and a number of storm events that resulted in pulsed urban runoff into the lake with rBC concentrations up to four orders of magnitude higher than mid-lake concentrations. The results show that elevated rBC concentrations from wildfire and urban runoff were rapidly attenuated in the lake, suggesting unexpected aggregation or degradation of the particles that prevent rBC concentrations from building up in the water of this lake, renowned for its clarity. The rBC concentrations were also measured in sediment cores from Lake Tahoe to evaluate the sediment archive as a potential combustion record. The evidence suggests that rBC is efficiently transferred to these sediments, which preserve a local-to-regional scale history of rBC emissions, as revealed by comparison with other pollutant records in the sediment. Rapid removal of rBC soon after entry into the lake has implications for transport of rBC in the global aquatic environment and flux of rBC from continents to the global ocean.

Using focal mechanism solutions to correlate earthquakes with faults in the Lake Tahoe-Truckee area, California and Nevada, and to help design LiDAR surveys for active-fault reconnaissance

NASA Astrophysics Data System (ADS)

Cronin, V. S.; Lindsay, R. D.

2011-12-01

Geomorphic analysis of hillshade images produced from aerial LiDAR data has been successful in identifying youthful fault traces. For example, the recently discovered Polaris fault just northwest of Lake Tahoe, California/Nevada, was recognized using LiDAR data that had been acquired by local government to assist land-use planning. Subsequent trenching by consultants under contract to the US Army Corps of Engineers has demonstrated Holocene displacement. The Polaris fault is inferred to be capable of generating a magnitude 6.4-6.9 earthquake, based on its apparent length and offset characteristics (Hunter and others, 2011, BSSA 101[3], 1162-1181). Dingler and others (2009, GSA Bull 121[7/8], 1089-1107) describe paleoseismic or geomorphic evidence for late Neogene displacement along other faults in the area, including the West Tahoe-Dollar Point, Stateline-North Tahoe, and Incline Village faults. We have used the seismo-lineament analysis method (SLAM; Cronin and others, 2008, Env Eng Geol 14[3], 199-219) to establish a tentative spatial correlation between each of the previously mentioned faults, as well as with segments of the Dog Valley fault system, and one or more earthquake(s). The ~18 earthquakes we have tentatively correlated with faults in the Tahoe-Truckee area occurred between 1966 and 2008, with magnitudes between 3 and ~6. Given the focal mechanism solution for a well-located shallow-focus earthquake, the nodal planes can be projected to Earth's surface as represented by a DEM, plus-or-minus the vertical and horizontal uncertainty in the focal location, to yield two seismo-lineament swaths. The trace of the fault that generated the earthquake is likely to be found within one of the two swaths [1] if the fault surface is emergent, and [2] if the fault surface is approximately planar in the vicinity of the focus. Seismo-lineaments from several of the earthquakes studied overlap in a manner that suggests they are associated with the same fault. The surface

Vertical distribution of a deep-water moss and associated epiphytes in Crater Lake, Oregon

USGS Publications Warehouse

McIntire, C.D.; Phinney, H.K.; Larson, Gary L.; Buktenica, M.W.

1994-01-01

A one-person submersible was used to examine the vertical distribution of the deep-water moss Drepanocladus aduncus (Hedw.) Warnst in Crater Lake (Oregon). Living specimens were found attached to sediment and rocks at depths between 25 m and 140 m. Dense beds of the moss were observed at depths between 30 m and 80 m, a region that corresponded roughly to the zone of maximum primary production by phytoplankton. The moss population supported a diverse assemblage of epiphytic algae, of which the most abundant genera included Cladophora,Oedogonium, Rhizoclonium, Tribonema, Vaucheria, and the diatoms Cocconeis, Cymbella, Epithemia, Fragilaria, Gomphonema, Melosira, Navicula, and Synedra. Chemical and physical data supported the hypothesis that the lower limit of distribution of the moss is determined by light limitation, whereas the upper limit is related to the availability of nutrients, particularly nitrate-nitrogen and trace elements. Deep-water videotapes of the moss population indicated that D. aduncus with its epiphytic algae was abundant enough in regions associated with the metalimnion and upper hypolimnion to have a potential influence on the nutrient dynamics of the Crater Lake ecosystem. Although the maximum depth at which living bryophytes occur in Crater Lake is similar to that found for Lake Tahoe, conditions in Lake Tahoe allow the growth and survival of a much more diverse assemblage of bryophytes and charophytes than is present in Crater Lake.

Photographic technology development project: Timber typing in the Tahoe Basin using high altitude panoramic photography

NASA Technical Reports Server (NTRS)

Ward, J. F.

1981-01-01

Procedures were developed and tested for using KA-80A optical bar camera panoramic photography for timber typing forest land and classifying nonforest land. The study area was the south half of the Lake Tahoe Basin Management Unit. Final products from this study include four timber type map overlays on 1:24,000 orthophoto maps. The following conclusions can be drawn from this study: (1) established conventional timber typing procedures can be used on panoramic photography if the necessary equipment is available, (2) The classification and consistency results warrant further study in using panoramic photography for timber typing; and (3) timber type mapping can be done as fast or faster with panoramic photography than with resource photography while maintaining comparable accuracy.

A hydrous Ca-bearing magnesium carbonate from playa lake sediments, Salines Lake, Spain

USGS Publications Warehouse

Queralt, I.; Julia, R.; Plana, F.; Bischoff, J.L.

1997-01-01

Sediments of playa Lake Salines, SE, Spain, contain a carbonate mineral characterized by X-ray diffraction peaks very similar to, but systematically shifted from those of pure magnesite. Analyses (SEM, IR and Raman spectroscopy, DTA, TGA, and ICP) indicate the mineral is a hydrous Ca-bearing magnesium carbonate with the chemical formula (Mg0.92,Ca0.08)CO3??3H2O. Thermal characteristics of the mineral are similar to those of other known hydrated magnesium carbonates. X-ray and electron diffraction data suggests a monoclinic system (P21/n space group) with unit-cell parameters of a = 6.063(6), b = 10.668(5), and c = 6.014(4) A?? and ?? = 107.28??.

The development and application of a decision support system for land management in the Lake Tahoe Basin—The Land Use Simulation Model

USGS Publications Warehouse

Forney, William M.; Oldham, I. Benson; Crescenti, Neil

2013-01-01

This report describes and applies the Land Use Simulation Model (LUSM), the final modeling product for the long-term decision support project funded by the Southern Nevada Public Land Management Act and developed by the U.S. Geological Survey’s Western Geographic Science Center for the Lake Tahoe Basin. Within the context of the natural-resource management and anthropogenic issues of the basin and in an effort to advance land-use and land-cover change science, this report addresses the problem of developing the LUSM as a decision support system. It includes consideration of land-use modeling theory, fire modeling and disturbance in the wildland-urban interface, historical land-use change and its relation to active land management, hydrologic modeling and the impact of urbanization as related to the Lahontan Regional Water Quality Control Board’s recently developed Total Maximum Daily Load report for the basin, and biodiversity in urbanizing areas. The LUSM strives to inform land-management decisions in a complex regulatory environment by simulating parcel-based, land-use transitions with a stochastic, spatially constrained, agent-based model. The tool is intended to be useful for multiple purposes, including the multiagency Pathway 2007 regional planning effort, the Tahoe Regional Planning Agency (TRPA) Regional Plan Update, and complementary research endeavors and natural-resource-management efforts. The LUSM is an Internet-based, scenario-generation decision support tool for allocating retired and developed parcels over the next 20 years. Because USGS staff worked closely with TRPA staff and their “Code of Ordinances” and analyzed datasets of historical management and land-use practices, this report accomplishes the task of providing reasonable default values for a baseline scenario that can be used in the LUSM. One result from the baseline scenario for the model suggests that all vacant parcels could be allocated within 12 years. Results also include

76 FR 62442 - Final Environmental Impact Report/Environmental Impact Statement for Upper Truckee River...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-07

... all factors leading to the decision. In late fall 2011, the California Parks and Recreation Commission... restoration with a reconfigured 18-hole golf course. DATES: Reclamation will complete a Record of Decision at... desk, 1000 Rufus Allen Boulevard, South Lake Tahoe, CA 96150. Hard copies can be printed for purchase...

NV: Nessus Vulnerability Visualization for the Web

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

Harrison, Lane; Spahn, Riley B; Iannacone, Michael D

2012-01-01

Network vulnerability is a critical component of network se- curity. Yet vulnerability analysis has received relatively lit- tle attention from the security visualization community. In this paper we describe nv, a web-based Nessus vulnerability visualization. Nv utilizes treemaps and linked histograms to allow system administrators to discover, analyze, and man- age vulnerabilities on their networks. In addition to visual- izing single Nessus scans, nv supports the analysis of sequen- tial scans by showing which vulnerabilities have been fixed, remain open, or are newly discovered. Nv was also designed to operate completely in-browser, to avoid sending sensitive data to outside servers.more » We discuss the design of nv, as well as provide case studies demonstrating vulnerability analysis workflows which include a multiple-node testbed and data from the 2011 VAST Challenge.« less

Distribution and variation of NV genes in fish rhabdoviruses

USGS Publications Warehouse

Kurath, G.; Higman, K.H.; Bjorklund, H.V.

1997-01-01

The fish rhabdovirus infectious haematopoietic necrosis virus (IHNV) contains a non-virion (NV) gene between the glycoprotein (G) and polymerase (L) genes on its RNA genome. The present study investigated three other fish rhabdovirus genomes and found that the NV gene of hirame rhabdovirus is closely related to the NV of IHNV, whereas the viral haemorrhagic septicemia NV gene showed evidence of significant divergence. Most importantly, spring viraemia of carp virus, the only vesiculovirus-like fish rhabdovirus examined, did not have an NV gene at its genomic RNA G-L junction. These results suggest that the presence of an NV gene is characteristic of the unassigned fish rhabdovirus subgroup previously classified as lyssaviruses, and that the NV gene is not essential for replication in fish cells per se, since it is absent in a vesiculovirus-like fish rhabdovirus.

76 FR 20942 - Humboldt (NV) Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-14

... DEPARTMENT OF AGRICULTURE Forest Service Humboldt (NV) Resource Advisory Committee AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Humboldt (NV) Resource Advisory Committee will meet... USDA Forest Service, 1500 E. Winnemucca Blvd., Winnemucca, NV 89445. Comments may also be sent via e...

Concerning KAr dating of a basalt flow from the Tahoe-Tioga interglaciation, Sawmill Canyon, southeastern Sierra Nevada, California

USGS Publications Warehouse

Dalrymple, G.B.; Burke, R.M.; Birkeland, P.W.

1982-01-01

New KAr ages for a basalt flow interbedded with Tahoe and Tioga tills in Sawmill Canyon, southeastern Sierra Nevada, slightly refine previously published ages for the flow and provide an estimate of 53,000 ± 44,000 yr for the Tahoe-Tioga interglaciation.

1. OVERVIEW OF MAIN ENTRANCE TO RESORT WITH STATE HIGHWAY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. OVERVIEW OF MAIN ENTRANCE TO RESORT WITH STATE HIGHWAY 89 IN FOREGROUND; MAIN LODGE IS ON THE FAR LEFT (WEST); CORD CABIN IS BEHIND AND TO THE RIGHT OF PARKED VEHICLES. - Camp Richardson Resort, Cord Cabin, U.S. Highway 89, 3 miles west of State Highway 50 & 89, South Lake Tahoe, El Dorado County, CA

77 FR 57556 - Lake Tahoe Basin Federal Advisory Committee (LTBFAC)

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-18

... updated information on Aquatic Invasive Species, fuels treatments, and biomass opportunities in the Lake...: The LTBFAC will receive updated information on Aquatic Invasive Species, fuels treatments, and biomass...

78 FR 38830 - Safety Zone; Execpro Services Fireworks Display, Lake Tahoe, Incline Village, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-28

... spectators from the dangers associated with the pyrotechnics. Unauthorized persons or vessels are prohibited... pyrotechnics used in this fireworks display, the safety zone is necessary to provide for the safety of event... loading, transit and arrival of the pyrotechnics from the loading site to the launch site and until the...

Seven Experiment Designs Addressing Problems of Safety and Capacity on Two-Lane Rural Highways : Volume 6. Experimental Design for Comparative Evaluation of Warning-Advisory and Regulatory Traffic Control Devices

DOT National Transportation Integrated Search

2006-04-14

This report presents the results of the national evaluation of the South Lake Tahoe coordinated Transit System (CTS) Project. The CTS Project involved combining transit services offered by private and public sector stakeholders in South Lake Tahoe in...

Atmospheric deposition of particles at a sensitive alpine lake: Size-segregated daily and annual fluxes from passive sampling techniques.

PubMed

Tai, Anna Y-C; Chen, L-W Antony; Wang, Xiaoliang; Chow, Judith C; Watson, John G

2017-02-01

Lake Tahoe, a North American alpine lake long appreciated for its clear water and geographic setting, has experienced a trend of declining water clarity due to increasing nutrient and particle inputs. Contributions from atmospheric deposition of particulate matter (PM) could be important, yet they are inadequately quantified. This study established a yearlong deposition monitoring network in the northern Lake Tahoe Basin. Dry deposition was quantified on surrogate surfaces while wet deposition was based on particles suspended in precipitation at 24-hour resolution. The particle size ranges by these passive techniques were 1-64μm and 0.5-20μm in diameter for dry and wet deposition, respectively. Dry deposition of submicrometer (0.5-1μm) particles was also estimated by extrapolation of a lognormal size distribution. Higher daily number deposition fluxes (NDF dry and NDF wet ) were found at a near-shore site, confirming substantial impacts of commercial and tourist activities. The two more isolated sites indicated a uniform regional background. On average, daily NDF dry is about one order of magnitude lower than daily NDF wet . Dry deposition velocities increased rapidly with particle size, as evidenced by collocated measurements of NDF dry and ambient particle number concentrations, though it seems less so for wet deposition due to different scavenging mechanisms. Despite fewer "wet" days than "dry" days during the monitoring period, wet processes dominated seasonal particle deposition, particularly in winter and spring when most precipitation occurred. Adopting sediment (insoluble, inorganic) particle fraction estimates from the literature, this study reports an annual particle flux of 2.9-5.2×10 10 #m -2 yr -1 for sediment particles with 1-20μm diameter and 6.1-11×10 10 #m -2 yr -1 for those with 0.5-20μm diameter. Implications of these findings to the current knowledge of atmospheric deposition in the Lake Tahoe Total Maximum Daily Load (TMDL) are discussed

Techniques for super-resolution microscopy using NV-diamond

NASA Astrophysics Data System (ADS)

Trifonov, Alexei; Glenn, David; Bar-Gill, Nir; Le Sage, David; Walsworth, Ronald

2011-05-01

We discuss the development and application of techniques for super-resolution microscopy using NV centers in diamond: stimulated emission depletion (STED), metastable ground state depletion (GSD), and stochastic optical reconstruction microscopy (STORM). NV centers do not bleach under optical excitation, are not biotoxic, and have long-lived electronic spin coherence and spin-state-dependent fluorescence. Thus NV-diamond has great potential as a fluorescent biomarker and as a magnetic biosensor.

76 FR 31627 - Notice of Realty Action: Competitive Sale of Public Lands in Lake County, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-01

...] Notice of Realty Action: Competitive Sale of Public Lands in Lake County, CA AGENCY: Bureau of Land... Field Office proposes to sell an 80-acre parcel of public land in Lake County, California. The sale will... proposed sale must be received by the BLM on or before July 11, 2011. Sealed bids must be received no later...

Integrated monitoring and assessment of soil restoration treatments in the Lake Tahoe Basin.

PubMed

Grismer, M E; Schnurrenberger, C; Arst, R; Hogan, M P

2009-03-01

Revegetation and soil restoration efforts, often associated with erosion control measures on disturbed soils, are rarely monitored or otherwise evaluated in terms of improved hydrologic, much less, ecologic function and longer term sustainability. As in many watersheds, sediment is a key parameter of concern in the Tahoe Basin, particularly fine sediments less than about ten microns. Numerous erosion control measures deployed in the Basin during the past several decades have under-performed, or simply failed after a few years and new soil restoration methods of erosion control are under investigation. We outline a comprehensive, integrated field-based evaluation and assessment of the hydrologic function associated with these soil restoration methods with the hypothesis that restoration of sustainable function will result in longer term erosion control benefits than that currently achieved with more commonly used surface treatment methods (e.g. straw/mulch covers and hydroseeding). The monitoring includes cover-point and ocular assessments of plant cover, species type and diversity; soil sampling for nutrient status; rainfall simulation measurement of infiltration and runoff rates; cone penetrometer measurements of soil compaction and thickness of mulch layer depths. Through multi-year hydrologic and vegetation monitoring at ten sites and 120 plots, we illustrate the results obtained from the integrated monitoring program and describe how it might guide future restoration efforts and monitoring assessments.

FOP 2012 stop, Honey Lake fault, Doyle, CA

USGS Publications Warehouse

Gold, Ryan; Briggs, Richard W.; Crone, Anthony; Angster, Steve; Seitz, Gordon G.

2012-01-01

The Honey Lake fault system (HLFS) strikes north-northwestward across Long Valley near Doyle, CA and is part of a network of active, dextral strike-slip faults in the northern Walker Lane (Figure 1). Geologic investigations of a right-laterally offset terrace riser along the north bank of Long Valley Creek, which we refer to as site 1 (Figure 2), indicate a latest Quaternary slip rate of 1.1-2. 6 mm/yr [Wills and Borchardt, 1993] and 1.7 ± 0.6 mm/yr [Turner and others, 2008] (Table 1). These studies also document evidence of at least four post-6.8 ka surface-rupturing earthquakes at this site.

Modeling transport of nutrients & sediment loads into Lake Tahoe under climate change

USGS Publications Warehouse

Riverson, John; Coats, Robert; Costa-Cabral, Mariza; Dettinger, Mike; Reuter, John; Sahoo, Goloka; Schladow, Geoffrey

2013-01-01

The outputs from two General Circulation Models (GCMs) with two emissions scenarios were downscaled and bias-corrected to develop regional climate change projections for the Tahoe Basin. For one model—the Geophysical Fluid Dynamics Laboratory or GFDL model—the daily model results were used to drive a distributed hydrologic model. The watershed model used an energy balance approach for computing evapotranspiration and snowpack dynamics so that the processes remain a function of the climate change projections. For this study, all other aspects of the model (i.e. land use distribution, routing configuration, and parameterization) were held constant to isolate impacts of climate change projections. The results indicate that (1) precipitation falling as rain rather than snow will increase, starting at the current mean snowline, and moving towards higher elevations over time; (2) annual accumulated snowpack will be reduced; (3) snowpack accumulation will start later; and (4) snowmelt will start earlier in the year. Certain changes were masked (or counter-balanced) when summarized as basin-wide averages; however, spatial evaluation added notable resolution. While rainfall runoff increased at higher elevations, a drop in total precipitation volume decreased runoff and fine sediment load from the lower elevation meadow areas and also decreased baseflow and nitrogen loads basin-wide. This finding also highlights the important role that the meadow areas could play as high-flow buffers under climatic change. Because the watershed model accounts for elevation change and variable meteorological patterns, it provided a robust platform for evaluating the impacts of projected climate change on hydrology and water quality.

Non-flipping 13C spins near an NV center in diamond: hyperfine and spatial characteristics by density functional theory simulation of the C510[NV]H252 cluster

NASA Astrophysics Data System (ADS)

Nizovtsev, A. P.; Kilin, S. Ya; Pushkarchuk, A. L.; Pushkarchuk, V. A.; Kuten, S. A.; Zhikol, O. A.; Schmitt, S.; Unden, T.; Jelezko, F.

2018-02-01

Single NV centers in diamond coupled by hyperfine interaction (hfi) to neighboring 13C nuclear spins are now widely used in emerging quantum technologies as elements of quantum memory adjusted to a nitrogen-vacancy (NV) center electron spin qubit. For nuclear spins with low flip-flop rate, single shot readout was demonstrated under ambient conditions. Here we report on a systematic search for such stable NV-13C systems using density functional theory to simulate the hfi and spatial characteristics of all possible NV-13C complexes in the H-terminated cluster C510[NV]-H252 hosting the NV center. Along with the expected stable ‘NV-axial-13C’ systems wherein the 13C nuclear spin is located on the NV axis, we found for the first time new families of positions for the 13C nuclear spin exhibiting negligible hfi-induced flipping rates due to near-symmetric local spin density distribution. Spatially, these positions are located in the diamond bilayer passing through the vacancy of the NV center and being perpendicular to the NV axis. Analysis of available publications showed that, apparently, some of the predicted non-axial near-stable NV-13C systems have already been observed experimentally. A special experiment performed on one of these systems confirmed the prediction made.

Laser spectroscopy of highly doped NV- centers in diamond

NASA Astrophysics Data System (ADS)

Subedi, Shova D.; Fedorov, Vladimir V.; Peppers, Jeremy; Martyshkin, Dmitry V.; Mirov, Sergey B.; Shao, Linbo; Loncar, Marko

2018-02-01

In this paper, prospects of using diamond with NV- centers as a gain medium have been studied. Spectroscopic characterization of NV- centers in diamond as well as absorption saturation and pump-probe experiments have been carried out. Absorption and emission cross-sections were estimated to be 2.8 × 10-17 cm2 and 4.3 × 10-17 cm2 at the maximum of absorption and emission bands, respectively. It was observed from emission spectra under pulse excitation that some NV- are photoionized to NV0 centers with ZPL at 575 nm. Room temperature luminescence lifetime of NV- centers was measured to be 12ns, which is close to the previously reported lifetime in bulk diamond ( 13ns). Saturated transmission was only about 11% of calculated values even at energy fluence much higher than the saturation flux. Two excited state absorptions (ESAs) with different relaxation times ("fast-decay" and "slow-decay with relaxation times of 500 ns and several tens of microseconds, respectively) were revealed in transmission decay kinetics at 632 nm. Kinetics of transmission at 670 nm was dominated by "slow-decay" ESA process. Kinetics of dk/k0 in shorter wavelength were strongly dominated by "fast-decay" ESA process. These results definitively indicate that stimulated emission of NV- centers is suppressed by photoionization and ESAs and the possibility of diamond lasers based on NV- centers is low.

Evolution of alkaline lakes - Lake Van case study

NASA Astrophysics Data System (ADS)

Tillman Meyer, Felix; Viehberg, Finn; Bahroun, Sonya; Wolf, Annabel; Immenhauser, Adrian; Kwiecien, Ola

2017-04-01

Lake Van in Eastern Anatolia (Turkey) is the largest terminal soda lake on Earth. The lake sedimentary profile covers ca. 600 ka (Stockhecke et al. 2014) Based on lithological changes, the presence of freshwater microfossils and close-to-freshwater pH value in the pore water, members of ICDP PALEOVAN concluded that Lake Van might have started as an open lake. Here we show paleontological and geochemical evidence in favour of this idea and constrain the time, when Lake Van likely transformed into a closed lake. Additionally we provide the first conceptual model of how this closure may have happened. Our archives of choice are inorganic and biogenic carbonates, separated by wet sieving. We identified microfossil assemblages (fraction > 125 µm) and performed high-resolution oxygen isotope (delta18O) and elemental (Mg/Ca, Sr/Ca) analyses of the fraction < 63 µm assuming that it represents only carbonates precipitating in the water column. Microfossil assemblage consists of three different species of ostracods (Candona spp, Loxoconcha sp, Amnicythere spp.), diatoms, gastropods and bivalves. Brakish-water ostracods, Loxoconcha sp and Amnicythere sp occur more often after 530 ka. Additionaly, Loxoconcha sp is a shallow-water species relaying on plants growing in the photic zone as food supply. These two aspects point to an increasing salinity in a shallowing lake. The delta18O values of inorganic carbonates are relatively low during the initial phase of Lake Van and increase abruptly (ca. 7‰) after 530 ka BP. At approximately the same time combination of Sr/Ca and Mg/Ca data suggest first occurrence of aragonite. Again, these findings suggest geochemical changes of the lake water concurrent with transition documented by microfossils. Comparison between Lake Van and Lake Ohrid (Lacey et al. 2016) delta18O data, precludes regional climate change (e.g.: increased evaporation) as the main driver of observed changes. With no evidence for increased volcanic or tectonic

Entanglement transfer from microwaves to diamond NV centers

NASA Astrophysics Data System (ADS)

Gomez, Angela V.; Rodriguez, Ferney J.; Quiroga, Luis

2014-03-01

Strong candidates to create quantum entangled states in solid-state environments are the nitrogen-vacancy (NV) defect centers in diamond. By the combination of radiation from different wavelength (optical, microwave and radio-frequency), several protocols have been proposed to create entangled states of different NVs. Recently, experimental sources of non-classical microwave radiation have been successfully realized. Here, we consider the entanglement transfer from spatially separated two-mode microwave squeezed (entangled) photons to a pair of NV centers by exploiting the fact that the spin triplet ground state of a NV has a natural splitting with a frequency on the order of GHz (microwave range). We first demonstrate that the transfer process in the simplest case of a single pair of spatially separated NVs is feasible. Moreover, we proceed to extend the previous results to more realistic scenarios where 13C nuclear spin baths surrounding each NV are included, quantifying the degradation of the entanglement transfer by the dephasing/dissipation effects produced by the nuclear baths. Finally, we address the issue of assessing the possibility of entanglement transfer from the squeezed microwave light to two nuclear spins closely linked to different NV center electrons. Facultad de Ciencias Uniandes.

NV-centers in nanodiamonds: How good they are

NASA Astrophysics Data System (ADS)

Plakhotnik, Taras; Aman, Haroon

2018-02-01

This paper presents a method for determination of the size distribution for diamond nanocrystals containing luminescent nitrogen-vacancy (NV) centers using the luminescence intensity only. We also revise the basic photo physical properties of NV centers and conclude that the luminescence quantum yield of such centers is significantly smaller than the frequently stated 100\\%. The yield can be as low as 5\\% for centers embedded in nanocrystals and depends on their shape and the refractive index of the surrounding medium. The paper also addresses the value of the absorption cross-section of NV centers.

Earth observations taken from orbiter Discovery during STS-85 mission

NASA Image and Video Library

1997-08-11

STS085-716-061 (7 - 19 August 1997) --- The dark green forests of the Sierra Nevada Mts. occupy the left side of the picture. Reno lies between Lake Tahoe (center) and Pyramid Lake (top right). Lake Tahoe, is a clear, deep alpine lake (over 505 meters deep), surrounded by Montane forest, ski resorts and casinos. Although Tahoe is known as one of the clearest lakes in the world, water quality in the lake has been declining due to soil erosion from development. Since 1968, it has lost about 30 feet of clarity. A partnership was recently formed between environmentalists and resort owners to protect their common interest in keeping the lake as clear as possible. Over the last five years they have slowed the erosion and the growth of algae that it causes so that clarity is now "only" lost at a rate of roughly one foot per year. Pyramid Lake (on the upper right of the photo) is as different from Tahoe as a lake could be. The sagebrush desert around the lake and is owned by the Pyramid Lake Paiute tribe who manage it as a fishery for an endangered sucker (fish), the cui-cui. The tribe has added modern fisheries' biology methods to their traditional management and chooses not to develop the lake as a recreation destination. Anaho Island, in the lower half of the lake, is a wildlife refuge managed for American White Pelicans which fly hundreds of miles each day to get from this safe breeding area to the shallow marshes where they feed. Directly above Lake Tahoe is Donner pass, near the site where the beleaguered Donner Party spent the winter of 1846 - 1847 trapped in the mountains. Several shallow ephemeral lakes can be seen in Lemmon Valley north of Reno's core urban area. These lakes would normally have dried up by August when this photo was taken, but are still wet because of the extremely wet winter and floods of January 1997.

MX Siting Investigation. Mineral Resources Survey, Seven Additional Valleys, Nevada/Utah Siting Area. Volume II.

DTIC Science & Technology

1981-06-23

Minerals Inc. Box 90 W. Grace #100 Reno NV 89509 Anaconda Copper Co. 555 17th Street Denver CO 80217 Argus Resources Inc. Box 56 Austin NV 93099 Armenian...Donald F. 7272 Lindale Drive Sacramento CA 95828 Combined Metals Red. 1865 S. Main St. Salt Lake City UT 84115 Conlan, Mary Helen N/A Copper Range Co...hApl. Co. Mineral Services co. N/A Miragliotta, Vito 1184 S. 1000 E. Clearfield UT 84015 Neeser, Earl Francis Box 495 Goldfield NV 89013 Nev. Porphyry

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

A variety of sedimentological evidence was used to construct the lake-level history for Bear Lake, Utah and Idaho, for the past ???25,000 years. Shorelines provide evidence of precise lake levels, but they are infrequently preserved and are poorly dated. For cored sediment similar to that in the modern lake, grain-size distributions provide estimates of past lake depths. Sedimentary textures provide a highly sensitive, continuous record of lake-level changes, but the modern distribution of fabrics is poorly constrained, and many ancient features have no modern analog. Combining the three types of data yields a more robust lake-level history than can be obtained from any one type alone. When smooth age-depth models are used, lake-level curves from multiple cores contain inconsistent intervals (i.e., one record indicates a rising lake level while another record indicates a falling lake level). These discrepancies were removed and the multiple records were combined into a single lake-level curve by developing age-depth relations that contain changes in deposition rate (i.e., gaps) where indicated by sedimentological evidence. The resultant curve shows that, prior to 18 ka, lake level was stable near the modern level, probably because the lake was overflowing. Between ca. 17.5 and 15.5 ka, lake level was ???40 m below the modern level, then fluctuated rapidly throughout the post-glacial interval. Following a brief rise centered ca. 15 ka ( = Raspberry Square phase), lake level lowered again to 15-20 m below modern from ca. 14.8-11.8 ka. This regression culminated in a lowstand to 40 m below modern ca. 12.5 ka, before a rapid rise to levels above modern ca. 11.5 ka. Lake level was typically lower than present throughout the Holocene, with pronounced lowstands 15-20 m below the modern level ca. 10-9, 7.0, 6.5-4.5, 3.5, 3.0-2.5, 2.0, and 1.5 ka. High lake levels near or above the modern lake occurred ca. 8.5-8.0, 7.0-6.5, 4.5-3.5, 2.5, and 0.7 ka. This lake-level history

77 FR 38005 - Safety Zone; Independence Day Fireworks, Kings Beach, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-26

... (NAD 83). From 9 a.m. to 11 a.m. on July 3, 2012, the loaded barge will transit from Tahoe Keys Marina to the launch site off of Kings Beach, CA at position 39[deg]13'55'' N, 120[deg]01'42'' W (NAD 83... within a radius 1,000 feet at position 39[deg]13'55'' N, 120[deg]01'42'' W (NAD 83) for the Kings Beach...

Aerosol Light Absorption and Scattering in Mexico City: Comparison With Las Vegas, NV, and Los Angeles, CA.

NASA Astrophysics Data System (ADS)

Paredes-Miranda, G.; Arnott, W. P.; Gaffney, J. S.; Marley, N. A.; Campbell, D.; Fujita, E.

2007-12-01

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 primary site in Mexico City was an urban site at Instituto Mexicano del Petroleo (Mexican Oil Institute, denoted by IMP). Similar campaigns were held in Las Vegas, NV in January-February, 2003; and Los Angeles, CA at numerous sites during all seasons from 2003 through 2007. The IMP site gave in-situ characterization of the Mexico City plume under favorable wind conditions. The photoacoustic instrument (PAS) used at IMP operates at 532 nm, and conveniently allowed for characterization of gaseous absorption at this wavelength as well. Light scattering measurements are accomplished within the PAS by the reciprocal nephelometery method. In Mexico City 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. 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 Mexico City resulted in more direct solar radiation. Further insight on the meteorological connections and population dynamics will be discussed.

Snowmelt Timing as a Determinant of Lake Inflow Mixing

NASA Astrophysics Data System (ADS)

Roberts, D. C.; Forrest, A. L.; Sahoo, G. B.; Hook, S. J.; Schladow, S. G.

2018-02-01

Snowmelt is a significant source of carbon, nutrient, and sediment loads to many mountain lakes. The mixing conditions of snowmelt inflows, which are heavily dependent on the interplay between snowmelt and lake thermal regime, dictate the fate of these loads within lakes and their ultimate impact on lake ecosystems. We use five decades of data from Lake Tahoe, a 600 year residence-time lake where snowmelt has little influence on lake temperature, to characterize the snowmelt mixing response to a range of climate conditions. Using stream discharge and lake profile data (1968-2017), we find that the proportion of annual snowmelt entering the lake prior to the onset of stratification increases as annual snowpack decreases, ranging from about 50% in heavy-snow years to close to 90% in warm, dry years. Accordingly, in 8 recent years (2010-2017) where hourly inflow buoyancy and discharge could be quantified, we find that decreased snowpack similarly increases the proportion of annual snowmelt entering the lake at weak to positive buoyancy. These responses are due to the stronger effect of winter precipitation conditions on streamflow timing and temperature than on lake stratification, and point toward increased nearshore and near-surface mixing of inflows in low-snowpack years. The response of inflow mixing conditions to snowpack is apparent when isolating temperature effects on snowpack. Snowpack levels are decreasing due to warming temperatures during winter precipitation. Thus, our findings suggest that climate change may lead to increased deposition of inflow loads in the ecologically dynamic littoral zone of high-residence time, snowmelt-fed lakes.

76 FR 13084 - Establishment of Area Navigation (RNAV) Routes; Western United States

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-10

... establishes seven High Altitude Area Navigation (RNAV) routes in the Western United States (U.S.). These new... flow from Salt Lake ARTCC to Reno, NV, and Sacramento, CA. The High Altitude RNAV Routes are published...

Registration of 'TifNV-High O/L' Peanut

USDA-ARS?s Scientific Manuscript database

‘TifNV-High O/L’ is a runner-type peanut (Arachis hypogaea L. subsp. hypogaea var. hypogaea) cultivar released by the USDA-ARS and the Georgia Agricultural Experiment Station in 2014. TifNV-High O/L was developed at the University of Georgia Coastal Plain Experiment Station, Tifton, GA. Our researc...

Groundwater quality in the Tahoe and Martis Basins, California

USGS Publications Warehouse

Fram, Miranda S.; Belitz, Kenneth

2012-01-01

Groundwater provides more than 40 percent of California's drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State's groundwater quality and increases public access to groundwater-quality information. The Tahoe and Martis Basins and surrounding watersheds constitute one of the study units being evaluated.

Evidence of norovirus (NV)in a major produce production region watershed and a low density microarray strategy for detecting NV(Abstract)

USDA-ARS?s Scientific Manuscript database

The presence of Norovirus (NV) in watersheds in the vicinity of raw produce production is a concern. This could occur due to leaking septic systems, improper RV waste removal, improperly treated recycled wastewater, or other unknown factors. We used a qRT-PCR method to test for NV in rinsates from M...

75 FR 29427 - Safety Zone; AVI May Fireworks Display, Laughlin, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-26

...-AA00 Safety Zone; AVI May Fireworks Display, Laughlin, NV AGENCY: Coast Guard, DHS. ACTION: Temporary... Colorado River, Laughlin, NV, in support of a fireworks display near the AVI Resort and Casino. This safety... Fireworks Display; Laughlin, Nevada, NV in the Federal Register (75 FR 9370). We received 0 comments on the...

Depletion-based techniques for super-resolution imaging of NV-diamond

NASA Astrophysics Data System (ADS)

Jaskula, Jean-Christophe; Trifonov, Alexei; Glenn, David; Walsworth, Ronald

2012-06-01

We discuss the development and application of depletion-based techniques for super-resolution imaging of NV centers in diamond: stimulated emission depletion (STED), metastable ground state depletion (GSD), and dark state depletion (DSD). NV centers in diamond do not bleach under optical excitation, are not biotoxic, and have long-lived electronic spin coherence and spin-state-dependent fluorescence. Thus NV-diamond has great potential as a fluorescent biomarker and as a magnetic biosensor.

The influences of the AMO and NAO on the sedimentary infill in an Azores Archipelago lake since ca. 1350 CE

NASA Astrophysics Data System (ADS)

Hernández, Armand; Sáez, Alberto; Bao, Roberto; Raposeiro, Pedro M.; Trigo, Ricardo M.; Doolittle, Sara; Masqué, Pere; Rull, Valentí; Gonçalves, Vítor; Vázquez-Loureiro, David; Rubio-Inglés, María J.; Sánchez-López, Guiomar; Giralt, Santiago

2017-07-01

The location of the Azores Archipelago in the North Atlantic makes this group of islands an excellent setting to study the long-term behavior of large oceanic and atmospheric climate dynamic patterns, such as the Atlantic Multidecadal Oscillation (AMO) and the North Atlantic Oscillation (NAO). Here, we present the impacts of these patterns on Lake Empadadas (Azores Archipelago) from the Medieval Climate Anomaly (MCA) - Little Ice Age (LIA) transition to the present based on sedimentological, geochemical and biological characterizations of the sedimentary record. Multivariate analyses of a number of proxies including X-ray fluorescence (XRF), X-ray diffraction (XRD), total organic and inorganic carbon (TOC and TIC) and diatom life forms abundance reveal that the sedimentary infill evolution has been controlled by (i) fluctuations in the lake level and (ii) variations in organic matter accumulation. Both processes are governed by climate variability and modulated by anthropogenic activities associated with changes on the lake catchment. Changes in these two sedimentary processes have been used to infer five stages: (i) the MCA-LIA transition (ca. 1350-1450 CE) was characterized by a predominantly positive AMO phase, which led to intermediate lake levels and high organic matter concentration; (ii) the first half of the LIA (ca. 1450-1600 CE) was characterized by predominant lowstand conditions and intermediate organic matter deposition mainly related to negative AMO phases; (iii) the second half of the LIA (ca. 1600-1850 CE) was characterized by negative AMO and NAO phases, implying intermediate lake levels and high organic matter deposition; (iv) the Industrial era (ca. 1850-1980 CE) was characterized by the lowest lake level and organic matter accumulation associated with negative AMO phases; and (v) the period spanning between 1980 CE and the present reveals the highest lake levels and low organic matter deposition, being associated with very positive AMO

Testing of SIR (a transformable robotic submarine) in Lake Tahoe for future deployment at West Antarctic Ice Sheet grounding lines of Siple Coast

NASA Astrophysics Data System (ADS)

Powell, R. D.; Scherer, R. P.; Griffiths, I.; Taylor, L.; Winans, J.; Mankoff, K. D.

2011-12-01

A remotely operated vehicle (ROV) has been custom-designed and built by DOER Marine to meet scientific requirements for exploring subglacial water cavities. This sub-ice rover (SIR) will explore and quantitatively document the grounding zone areas of the Ross Ice Shelf cavity using a 3km-long umbilical tether by deployment through an 800m-long ice borehole in a torpedo shape, which is also its default mode if operational failure occurs. Once in the ocean cavity it transforms via a diamond-shaped geometry into a rectangular form when all of its instruments come alive in its flight mode. Instrumentation includes 4 cameras (one forward-looking HD), a vertical scanning sonar (long-range imaging for spatial orientation and navigation), Doppler current meter (determine water current velocities), multi-beam sonar (image and swath map bottom topography), sub-bottom profiler (profile sub-sea-floor sediment for geological history), CTD (determine salinity, temperature and depth), DO meter (determine dissolved oxygen content in water), transmissometer (determine suspended particulate concentrations in water), laser particle-size analyzer (determine sizes of particles in water), triple laser-beams (determine size and volume of objects), thermistor probe (measure in situ temperatures of ice and sediment), shear vane probe (determine in situ strength of sediment), manipulator arm (deploy instrumentation packages, collect samples), shallow ice corer (collect ice samples and glacial debris), water sampler (determine sea water/freshwater composition, calibrate real-time sensors, sample microbes), shallow sediment corer (sample sea floor, in-ice and subglacial sediment for stratigraphy, facies, particle size, composition, structure, fabric, microbes). A sophisticated array of data handling, storing and displaying will allow real-time observations and environmental assessments to be made. This robotic submarine and other instruments will be tested in Lake Tahoe in September, 2011 and

75 FR 51180 - Safety Zone; AVI September Fireworks Display, Laughlin, Nevada, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-19

...-AA00 Safety Zone; AVI September Fireworks Display, Laughlin, Nevada, NV AGENCY: Coast Guard, DHS... waters of the lower Colorado River, Laughlin, NV, in support of a fireworks display near the AVI Resort... Zone; AVI September Fireworks Display; Laughlin, Nevada, NV in the Federal Register (75 FR 23206). We...

A nuclear localization of the infectious haematopoietic necrosis virus NV protein is necessary for optimal viral growth

USGS Publications Warehouse

Choi, M.K.; Moon, C.H.; Ko, M.S.; Lee, U.-H.; Cho, W.; Cha, S.J.; Do, J.W.; Heo, G.J.; Jeong, S.G.; Hahm, Y.S.; Harmache, A.; Bremont, M.; Kurath, G.; Park, J.-W.

2011-01-01

The nonvirion (NV) protein of infectious hematopoietic necrosis virus (IHNV) has been previously reported to be essential for efficient growth and pathogenicity of IHNV. However, little is known about the mechanism by which the NV supports the viral growth. In this study, cellular localization of NV and its role in IHNV growth in host cells was investigated. Through transient transfection in RTG-2 cells of NV fused to green fluorescent protein (GFP), a nuclear localization of NV was demonstrated. Deletion analyses showed that the 32EGDL35 residues were essential for nuclear localization of NV protein, and fusion of these 4 amino acids to GFP directed its transport to the nucleus. We generated a recombinant IHNV, rIHNV-NV-ΔEGDL in which the 32EGDL35 was deleted from the NV. rIHNVs with wild-type NV (rIHNV-NV) or with the NV gene replaced with GFP (rIHNV-ΔNV-GFP) were used as controls. RTG-2 cells infected with rIHNV-ΔNV-GFP and rIHNV-NV-ΔEGDL yielded 12- and 5-fold less infectious virion, respectively, than wild type rIHNV-infected cells at 48 h post-infection (p.i.). While treatment with poly I:C at 24 h p.i. did not inhibit replication of wild-type rIHNVs, replication rates of rIHNV-ΔNV-GFP and rIHNV-NV-ΔEGDL were inhibited by poly I:C. In addition, both rIHNV-ΔNV and rIHNV-NV-ΔEGDL induced higher levels of expressions of both IFN1 and Mx1 than wild-type rIHNV. These data suggest that the IHNV NV may support the growth of IHNV through inhibition of the INF system and the amino acid residues of 32EGDL35 responsible for nuclear localization are important for the inhibitory activity of NV.

76 FR 75446 - Amendment of Class E Airspace; Mercury, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-02

...-0894; Airspace Docket No. 11-AWP-14] Amendment of Class E Airspace; Mercury, NV AGENCY: Federal... Mercury, Desert Rock Airport, Mercury, NV. Decommissioning of the Mercury Non-Directional Beacon (NDB) at Mercury, Desert Rock Airport has made this action necessary for the safety and management of Instrument...

AmeriFlux CA-Na1 New Brunswick - 1967 Balsam Fir - Nashwaak Lake Site 01 (Mature balsam fir forest)

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

Bourque, Charles P.-A.

This is the AmeriFlux version of the carbon flux data for the site CA-Na1 New Brunswick - 1967 Balsam Fir - Nashwaak Lake Site 01 (Mature balsam fir forest). Site Description - immature balsam fir forest

75 FR 21341 - Millerton Lake Resource Management Plan/General Plan (RMP/GP), Madera and Fresno Counties, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-23

... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Millerton Lake Resource Management Plan/General Plan (RMP/GP), Madera and Fresno Counties, CA AGENCY: Bureau of Reclamation, Interior. ACTION: Notice... adoption of the RMP/GP. The Final EIS/EIR outlines the formulation and evaluation of alternatives designed...

75 FR 9370 - Safety Zone; AVI May Fireworks Display, Colorado River, Laughlin, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-02

...-AA00 Safety Zone; AVI May Fireworks Display, Colorado River, Laughlin, NV AGENCY: Coast Guard, DHS... waters of the lower Colorado River, Laughlin, NV, in support of a fireworks display near the AVI Resort... navigable waters of the Lower Colorado River in support of a fireworks show near Laughlin, NV. The fireworks...

A Major Eocene Lake System in the Hinterland of the North American Cordillera Comes into Geochronologic Focus

NASA Astrophysics Data System (ADS)

Smith, M. E.; Cassel, E. J.; Canada, A.; Jicha, B.; Singer, B. S.

2015-12-01

Eastern Nevada lay east of the Cordilleran continental divide and experienced continental drainage ponding during the Eocene Epoch. Though recognized for nearly a century, lake deposits of the Elko Formation have yet to be placed in a regional chronostratigraphic context, due primarily to Neogene extension and a paucity of radioisotopic ages. New geochronology is essential for creating robust reconstructions of paleogeography and paloeohydrology from scattered surviving outcrops, and for assessing competing tectonic interpretations for lake basin formation and evolution. New single crystal sanidine 40Ar/39Ar ages for 21 ash beds collected from the Elko Formation and contemporaneous fluvial deposits indicate that lacustrine deposition occurred locally as early as ca. 48.7 Ma, coeval with deposition of the Bridgerian portion of the lacustrine Sheep Pass Formation to the south. Lake Elko's most expansive phase occurred between ca. 44.0 and 40.5 Ma, resulting in regional overlap of lacustrine strata atop fluvial strata. Based on lithofacies and lithofacies stacking patterns, an up-section transition from overfilled to balanced-fill conditions occurred at ca. 41.3 Ma. This transition led to increasing salinity and lake level variations that formed a prominent 1-4 meter-scale depositional cyclicity characteristic of partly closed lakes that periodically dropped below their sill elevation. The stromatolitic uppermost Elko Formation records proximal volcanism, including several welded ignimbrites, and is overlain by an unconformity of >10 m.y. duration. Initial ponding, the shift to balanced fill conditions, voluminous siliceous volcanism, and subsequent unconformity are interpreted to reflect the progressive NE to SW advance of 500-900 m of topographic uplift and volcanism resulting from rollback of the Farallon slab. 40Ar/39Ar ages for ash beds at five individual locations suggest that a single ignimbrite, likely the Tuff of Nelson Creek, was deposited across a ~10

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.

Super-resolution optical imaging and magnetometry using NV centers in diamond

NASA Astrophysics Data System (ADS)

Jaskula, Jean-Christophe; Trifonov, Alexei; Glenn, David; Bar-Gill, Nir; Walsworth, Ronald

2013-05-01

We report progress done on the development and application of depletion-based techniques for super-resolution (nanoscale) optical imaging and magnetometry using NV centers in diamond. In particulare we are integrating stimulated emission depletion (STED) and ground state depletion (GSD) imaging techniques with advanced pulsed sequences for AC magnetometry. NV centers in diamond do not bleach under optical excitation, have long-lived electronic spin coherence and spin-state-dependent fluorescence, and are not biotoxic. Thus NV-diamond has great potential in quantum science and as a nanoscale magnetic biosensor.

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

Ca isotopic geochemistry of an Antarctic aquatic system

USGS Publications Warehouse

Lyons, W. Berry; Bullen, Thomas D.; Welch, Kathleen A.

2017-01-01

The McMurdo Dry Valleys, Antarctica, are a polar desert ecosystem. The hydrologic system of the dry valleys is linked to climate with ephemeral streams that flow from glacial melt during the austral summer. Past climate variations have strongly influenced the closed-basin, chemically stratified lakes on the valley floor. Results of previous work point to important roles for both in-stream processes (e.g., mineral weathering, precipitation and dissolution of salts) and in-lake processes (e.g., mixing with paleo-seawater and calcite precipitation) in determining the geochemistry of these lakes. These processes have a significant influence on calcium (Ca) biogeochemistry in this aquatic ecosystem, and thus variations in Ca stable isotope compositions of the waters can aid in validating the importance of these processes. We have analyzed the Ca stable isotope compositions of streams and lakes in the McMurdo Dry Valleys. The results validate the important roles of weathering of aluminosilicate minerals and/or CaCO3 in the hyporheic zone of the streams, and mixing of lake surface water with paleo-seawater and precipitation of Ca-salts during cryo-concentration events to form the deep lake waters. The lakes in the McMurdo Dry Valleys evolved following different geochemical pathways, evidenced by their unique, nonsystematic Ca isotope signatures.

Enhanced photoelectric detection of NV magnetic resonances in diamond under dual-beam excitation

NASA Astrophysics Data System (ADS)

Bourgeois, E.; Londero, E.; Buczak, K.; Hruby, J.; Gulka, M.; Balasubramaniam, Y.; Wachter, G.; Stursa, J.; Dobes, K.; Aumayr, F.; Trupke, M.; Gali, A.; Nesladek, M.

2017-01-01

The core issue for the implementation of NV center qubit technology is a sensitive readout of the NV spin state. We present here a detailed theoretical and experimental study of NV center photoionization processes, used as a basis for the design of a dual-beam photoelectric method for the detection of NV magnetic resonances (PDMR). This scheme, based on NV one-photon ionization, is significantly more efficient than the previously reported single-beam excitation scheme. We demonstrate this technique on small ensembles of ˜10 shallow NVs implanted in electronic grade diamond (a relevant material for quantum technology), on which we achieve a cw magnetic resonance contrast of 9%—three times enhanced compared to previous work. The dual-beam PDMR scheme allows independent control of the photoionization rate and spin magnetic resonance contrast. Under a similar excitation, we obtain a significantly higher photocurrent, and thus an improved signal-to-noise ratio, compared to single-beam PDMR. Finally, this scheme is predicted to enhance magnetic resonance contrast in the case of samples with a high proportion of substitutional nitrogen defects, and could therefore enable the photoelectric readout of single NV spins.

76 FR 56127 - Proposed Amendment of Class E Airspace; Mercury, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-12

...-0894; Airspace Docket No. 11-AWP-14] Proposed Amendment of Class E Airspace; Mercury, NV AGENCY... action proposes to amend Class E airspace at Mercury, Desert Rock Airport, Mercury, NV. Decommissioning of the Mercury Non- Directional Beacon (NDB) at Mercury, Desert Rock Airport has made this action...

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.

75 FR 23206 - Safety Zone; AVI September Fireworks Display, Laughlin, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-03

...-AA00 Safety Zone; AVI September Fireworks Display, Laughlin, NV AGENCY: Coast Guard, DHS. ACTION... the lower Colorado River, Laughlin, NV, in support of a fireworks display near the AVI Resort and... navigable waters of the Lower Colorado River in support of a fireworks show in the navigation channel of the...

Lake Eyre

Atmospheric Science Data Center

2013-04-16

... lake, and becomes dense with birds, frogs and colorful plant life. The Lake responds to extended dry periods (often associated with El Niño ... NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Science Mission Directorate, Washington, D.C. The Terra spacecraft is managed ...

78 FR 33047 - Humboldt-Toiyabe National Forest, Carson Ranger District Mt. Rose Ski Tahoe-Atoma Area...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-03

... the effects of a proposal from Mt. Rose Ski Tahoe (Mt. Rose) to expand its lift and terrain network... to create the Atoma lift and trail ``Pod'' to the north of the Mt. Rose Highway. The proposed Atoma... facilitate construction and [[Page 33048

Hydrological and solute budgets of Lake Qinghai, the largest lake on the Tibetan Plateau

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

Jin, Zhangdong; You, Chen-Feng; Wang, Yi

2009-12-04

Water level and chemistry of Lake Qinghai are sensitive to climate changes and are important for paleoclimatic implications. An accurate understanding of hydrological and chemical budgets is crucial for quantifying geochemical proxies and carbon cycle. Published results of water budget are firstly reviewed in this paper. Chemical budget and residence time of major dissolved constituents in the lake are estimated using reliable water budget and newly obtained data for seasonal water chemistry. The results indicate that carbonate weathering is the most important riverine process, resulting in dominance of Ca 2+ and DIC for river waters and groundwater. Groundwater contribution tomore » major dissolved constituents is relatively small (4.2 ± 0.5%). Wet atmospheric deposition contributes annually 7.4–44.0% soluble flux to the lake, resulting from eolian dust throughout the seasons. Estimates of chemical budget further suggest that (1) the Buha-type water dominates the chemical components of the lake water, (2) Na +, Cl -, Mg 2+ , and K + in lake water are enriched owing to their conservative behaviors, and (3) precipitation of authigenic carbonates (low-Mg calcite, aragonite, and dolomite) transits quickly dissolved Ca 2+ into the bottom sediments of the lake, resulting in very low Ca 2+ in the lake water. Therefore, authigenic carbonates in the sediments hold potential information on the relative contribution of different solute inputs to the lake and the lake chemistry in the past.« less

AmeriFlux CA-Cha New Brunswick - Charlie Lake site 01 (immature balsam fir forest to be thinned in year 3)

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

Bourque, Charles

This is the AmeriFlux version of the carbon flux data for the site CA-Cha New Brunswick - Charlie Lake site 01 (immature balsam fir forest to be thinned in year 3). Site Description - mature balsam fir forest

RadNet Air Data From Reno, NV

EPA Pesticide Factsheets

This page presents radiation air monitoring and air filter analysis data for Reno, NV from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

NV Diamond Micro-Magnetometer Baseline Studies

DTIC Science & Technology

2009-08-12

to define circular masks of diameters ranging from 100-250nm on the surface. An anisotropic etch was used to transfer the pattern into the crystal...between NV and nearby 13C. (b) Pulse sequence for transfer of electron spin coherence to nuclear spin and repetitive readout. (c) Cumulative Rabi

Searching for Variability of NV Intrinsic Narrow Absorption Line Systems

NASA Astrophysics Data System (ADS)

Rodruck, Michael; Charlton, Jane; Ganguly, Rajib

2018-01-01

The majority of quasar absorption line systems with NV detected are found within the associated region (within 5000 km/s of the quasar redshift) and many/most are believed to be related to the quasar accretion disk wind or outflows. The most definite evidence that these NV absorbers are "intrinsic" is partial covering of the quasar continuum source and/or broad line region. Over 75 quasars containing NV narrow absorption lines have observations obtained at different times with the Keck/HIRES and the VLT/UVES spectrographs at high resolution. The interval between these observations range from months to a decade in the quasar rest frame. While variability is common for intrinsic broad and mini-broad absorption lines, intrinsic narrow absorption lines have been found to be less likely to vary, though systematic studies with large, high quality datasets have been limited. The variability timescales are useful for deriving gas densities and thus the distances from the central engines. This is important in mapping the quasar surroundings, understanding the accretion disk wind mechanism, and assessing the effect the wind has on the galaxy surroundings. We report on the results of a systematic study of variability of NV NALs, exploiting the overlap of targets for observations in the archives of Keck and VLT, and discuss the consequences for interpretation of the origin of intrinsic narrow absorption lines.

Evaluation of the Use of Dark and Bright Targets for the In-Flight Calibration of AVIRIS

NASA Technical Reports Server (NTRS)

Thome, K.; Parada, R.; Schiller, S.; Conel, J.; LaMarr, J.

1998-01-01

During a field campaign at Lake Tahoe on June 22, 1995, calibrations of AVIRIS were attempted using both the reflectance-based and radiance-based methods. This experiment shows that the use of dark water targets to calibrate radiometric sensors can result in meaningful sensor characterization. In particular, the reflectance-based method shows promise towards meeting the desired 2-3% uncertainty levels for ocean color sensors since experimental agreement of better than 1.5% is found for the Lake Tahoe AVIRIS experiment. Similarly promising results were found from reflectance-based calibrations at Lunar Lake with large portions of the spectrum having less than a 5% difference between the reflectance-based predictions and the measured AVIRIS radiances. These results are still in the preliminary stage and it is likely that further study of this data set will lead to even better agreement. The results of the radiance-based calibration at Lake Tahoe are quite good at the shorter wavelengths where atmospheric scattering leads to larger signals and smaller effects of specularly reflected solar energy. The results also showed the sensitivity to radiometer pointing when using water targets for vicarious calibration.

Climate change impacts on lake thermal dynamics and ecosystem vulnerabilities

USGS Publications Warehouse

Sahoo, G. B; Forrest, A. L; Schladow, S. G ;; Reuter, J. E; Coats, R.; Dettinger, Michael

2016-01-01

Using water column temperature records collected since 1968, we analyzed the impacts of climate change on thermal properties, stability intensity, length of stratification, and deep mixing dynamics of Lake Tahoe using a modified stability index (SI). This new SI is easier to produce and is a more informative measure of deep lake stability than commonly used stability indices. The annual average SI increased at 16.62 kg/m2/decade although the summer (May–October) average SI increased at a higher rate (25.42 kg/m2/decade) during the period 1968–2014. This resulted in the lengthening of the stratification season by approximately 24 d. We simulated the lake thermal structure over a future 100 yr period using a lake hydrodynamic model driven by statistically downscaled outputs of the Geophysical Fluid Dynamics Laboratory Model (GFDL) for two different green house gas emission scenarios (the A2 in which greenhouse-gas emissions increase rapidly throughout the 21st Century, and the B1 in which emissions slow and then level off by the late 21st Century). The results suggest a continuation and intensification of the already observed trends. The length of stratification duration and the annual average lake stability are projected to increase by 38 d and 12 d and 30.25 kg/m2/decade and 8.66 kg/m2/decade, respectively for GFDLA2 and GFDLB1, respectively during 2014–2098. The consequences of this change bear the hallmarks of climate change induced lake warming and possible exacerbation of existing water quality, quantity and ecosystem changes. The developed methodology could be extended and applied to other lakes as a tool to predict changes in stratification and mixing dynamics.

Chapter 6: Ecology and Biodiversity

Treesearch

Patricia N. Manley; Dennis D. Murphy; Seth Bigelow; Sudeep Chandra

2010-01-01

The integrity of animal and plant communities serves as a critical measure of the effectiveness of policies designed to protect and restore ecosystem processes in the Lake Tahoe basin. The conservation of plants and animals in the Tahoe basin is utterly dependent on the conservation of its terrestrial and aquatic ecosystems; so, in many ways, the research agenda that...

Gene Diversification of an Emerging Pathogen: A Decade of Mutation in a Novel Fish Viral Hemorrhagic Septicemia (VHS) Substrain since Its First Appearance in the Laurentian Great Lakes

PubMed Central

Leaman, Douglas W.; Niner, Megan D.; Shepherd, Brian S.

2015-01-01

Viral Hemorrhagic Septicemia virus (VHSv) is an RNA rhabdovirus, which causes one of the world's most serious fish diseases, infecting >80 freshwater and marine species across the Northern Hemisphere. A new, novel, and especially virulent substrain—VHSv-IVb—first appeared in the Laurentian Great Lakes about a decade ago, resulting in massive fish kills. It rapidly spread and has genetically diversified. This study analyzes temporal and spatial mutational patterns of VHSv-IVb across the Great Lakes for the novel non-virion (Nv) gene that is unique to this group of novirhabdoviruses, in relation to its glycoprotein (G), phosphoprotein (P), and matrix (M) genes. Results show that the Nv-gene has been evolving the fastest (k = 2.0x10-3 substitutions/site/year), with the G-gene at ~1/7 that rate (k = 2.8x10-4). Most (all but one) of the 12 unique Nv- haplotypes identified encode different amino acids, totaling 26 changes. Among the 12 corresponding G-gene haplotypes, seven vary in amino acids with eight total changes. The P- and M- genes are more evolutionarily conserved, evolving at just ~1/15 (k = 1.2x10-4) of the Nv-gene’s rate. The 12 isolates contained four P-gene haplotypes with two amino acid changes, and six M-gene haplotypes with three amino acid differences. Patterns of evolutionary changes coincided among the genes for some of the isolates, but appeared independent in others. New viral variants were discovered following the large 2006 outbreak; such differentiation may have been in response to fish populations developing resistance, meriting further investigation. Two 2012 variants were isolated by us from central Lake Erie fish that lacked classic VHSv symptoms, having genetically distinctive Nv-, G-, and M-gene sequences (with one of them also differing in its P-gene); they differ from each other by a G-gene amino acid change and also differ from all other isolates by a shared Nv-gene amino acid change. Such rapid evolutionary differentiation may

Evidence for Large Hydrologic and Ecologic Variability During the Late Wisconsin in the Coastal Southwest United States (Lake Elsinore, CA)

NASA Astrophysics Data System (ADS)

Kirby, M.; Heusser, L. E.; Scholz, C. A.; Anderson, M.; Rhodes, E. J.; Hiner, C.; Palermo, J. A.; Silveira, E.

2016-12-01

Future climate change is expected to alter the planet's water cycle, thus stressing water resources and ecologic stability. This impact is predicted to be especially significant in arid environments. Unfortunately, continuous, sub-centennially resolved paleo-terrestrial records are rare from arid environments such as the coastal southwest US (cswUS). Lake Elsinore, a pull-apart basin located 90 km SE of Los Angeles CA, is the largest natural lake in the cswUS. Gravity studies indicate nearly 1000 m of sediments occupy the basin. A recent seismic reflection survey imaged the upper 60-80 m of sediment, revealing continuous sediment accumulation. Here, we present a decadal-to-multi-decadal lacustrine sediment core record used to assess the relationship between vegetation (i.e., pollen) and run-off variability (i.e., grain size) during the late Wisconsin (10-32 kyrs BP). In general, the late Wisconsin is characterized by run-off greater than during the Holocene, indicating more frequent winter storms and/or higher intensity precipitation. A notable dry period, however, exists between 25.5-27.5 kyrs BP (Heusser et al., 2015), where lake level regressed but did not desiccate. Modern lake-level - grain size relationships are used to assess paleo-lake levels during this glacial mega-drought. Peak run-off occurs between 14.7 and 19.8 kyrs BP, generally post-dating the global LGM. A two-step decrease in run-off characterize the B-A to YD to Holocene (Kirby et al., 2013). Vegetation shows a fairly strong coupling to the run-off indicator, signifying rapid ecologic responses to changes in regional hydroclimates. This run-off - vegetation coupling is especially relevant to understanding future vegetative responses in the CA Floristic Province Biodiversity Hotspot. Finally, results are compared to potential forcings such as winter-summer insolation, Pacific SSTs, and Atlantic Meridional Overturning Circulation as well as regional paleo-records.

The springs of Lake Pátzcuaro: chemistry, salt-balance, and implications for the water balance of the lake

USGS Publications Warehouse

Bischoff, James L.; Israde-Alcántara, Isabel; Garduno-Monroy, Victor H.; Shanks, Wayne C.

2004-01-01

Lake Pa??tzcuaro, the center of the ancient Tarascan civilization located in the Mexican altiplano west of the city of Morelia, has neither river input nor outflow. The relatively constant lake-salinity over the past centuries indicates the lake is in chemical steady state. Springs of the south shore constitute the primary visible input to the lake, so influx and discharge must be via sub-lacustrine ground water. The authors report on the chemistry and stable isotope composition of the springs, deeming them representative of ground-water input. The springs are dominated by Ca, Mg and Na, whereas the lake is dominated by Na. Combining these results with previously published precipitation/rainfall measurements on the lake, the authors calculate the chemical evolution from spring water to lake water, and also calculate a salt balance of the ground-water-lake system. Comparing Cl and ??18O compositions in the springs and lake water indicates that 75-80% of the spring water is lost evaporatively during evolution toward lake composition. During evaporation Ca and Mg are lost from the water by carbonate precipitation. Each liter of spring water discharging into the lake precipitates about 18.7 mg of CaCO3. Salt balance calculations indicate that ground water input to the lake is 85.9??106 m3/a and ground water discharge from the lake is 23.0??106 m3/a. Thus, the discharge is about 27% of the input, with the rest balanced by evaporation. A calculation of time to reach steady-state ab initio indicates that the Cl concentration of the present day lake would be reached in about 150 a. ?? 2004 Elsevier Ltd. All rights reserved.

The jellification of north temperate lakes

PubMed Central

Jeziorski, Adam; Tanentzap, Andrew J.; Yan, Norman D.; Paterson, Andrew M.; Palmer, Michelle E.; Korosi, Jennifer B.; Rusak, James A.; Arts, Michael T.; Keller, Wendel (Bill); Ingram, Ron; Cairns, Allegra; Smol, John P.

2015-01-01

Calcium (Ca) concentrations are decreasing in softwater lakes across eastern North America and western Europe. Using long-term contemporary and palaeo-environmental field data, we show that this is precipitating a dramatic change in Canadian lakes: the replacement of previously dominant pelagic herbivores (Ca-rich Daphnia species) by Holopedium glacialis, a jelly-clad, Ca-poor competitor. In some lakes, this transformation is being facilitated by increases in macro-invertebrate predation, both from native (Chaoborus spp.) and introduced (Bythotrephes longimanus) zooplanktivores, to which Holopedium, with its jelly coat, is relatively invulnerable. Greater representation by Holopedium within cladoceran zooplankton communities will reduce nutrient transfer through food webs, given their lower phosphorus content relative to daphniids, and greater absolute abundances may pose long-term problems to water users. The dominance of jelly-clad zooplankton will likely persist while lakewater Ca levels remain low. PMID:25411451

A mass balance mercury budget for a mine-dominated lake: Clear Lake, California

USGS Publications Warehouse

Suchanek, T.H.; Cooke, J.; Keller, K.; Jorgensen, S.; Richerson, P.J.; Eagles-Smith, Collin A.; Harner, E.J.; Adam, D.P.

2009-01-01

The Sulphur Bank Mercury Mine (SBMM), active intermittently from 1873–1957 and now a USEPA Superfund site, was previously estimated to have contributed at least 100 metric tons (105 kg) of mercury (Hg) into the Clear Lake aquatic ecosystem. We have confirmed this minimum estimate. To better quantify the contribution of the mine in relation to other sources of Hg loading into Clear Lake and provide data that might help reduce that loading, we analyzed Inputs and Outputs of Hg to Clear Lake and Storage of Hg in lakebed sediments using a mass balance approach. We evaluated Inputs from (1) wet and dry atmospheric deposition from both global/regional and local sources, (2) watershed tributaries, (3) groundwater inflows, (4) lakebed springs and (5) the mine. Outputs were quantified from (1) efflux (volatilization) of Hg from the lake surface to the atmosphere, (2) municipal and agricultural water diversions, (3) losses from out-flowing drainage of Cache Creek that feeds into the California Central Valley and (4) biotic Hg removal by humans and wildlife. Storage estimates include (1) sediment burial from historic and prehistoric periods (over the past 150–3,000 years) from sediment cores to ca. 2.5m depth dated using dichloro diphenyl dichloroethane (DDD), 210Pb and 14C and (2) recent Hg deposition in surficial sediments. Surficial sediments collected in October 2003 (11 years after mine site remediation) indicate no reduction (but a possible increase) in sediment Hg concentrations over that time and suggest that remediation has not significantly reduced overall Hg loading to the lake. Currently, the mine is believed to contribute ca. 322–331 kg of Hg annually to Clear Lake, which represents ca. 86–99% of the total Hg loading to the lake. We estimate that natural sedimentation would cover the existing contaminated sediments within ca. 150–300 years.

Natural aquatic insect carriers of Macrobrachium rosenbergii nodavirus (MrNV) and extra small virus (XSV).

PubMed

Sudhakaran, R; Haribabu, P; Kumar, S Rajesh; Sarathi, M; Ahmed, V P Ishaq; Babu, V Sarath; Venkatesan, C; Hameedl, A S Sahul

2008-04-01

Five different species of aquatic insects were collected from nursery ponds containing the freshwater prawn Macrobrachium rosenbergii infected with Macrobrachium rosenbergii nodavirus (MrNV) and extra small virus (XSV). The insects were screened as potential natural carriers of MrNV and XSV. RT-PCR (reverse transcription polymerase chain reaction) analysis gave positive results for MrNV and XSV in Belostoma sp., Aesohna sp., Cybister sp. and Notonecta sp., and negative results for Nepa sp. An Aedes albopictus mosquito cell line (C6/36) was used for infectivity assays, with viral inoculum prepared from the aquatic insects, since C6/36 cells have recently been shown to be susceptible to infection with MrNV and XSV. The C6/36 cells were harvested 4 d post-challenge for examination by electron microscopy. This revealed aggregation of viral particles throughout the cytoplasm for cells challenged with inocula from all the insect species except Nepa sp. Our results indicate that several aquatic insect species may present a risk for MrNV and XSV transmission to M. rosenbergii.

An assessment of the Ca weathering sources to surface waters on the Precambrian Shield in central Ontario.

PubMed

Watmough, Shaun

2018-06-01

There is increasing concern over the negative ecological impacts caused by falling calcium (Ca) concentrations in lakes, particularly in central Ontario, Canada. Forecasting regional changes in lake Ca concentrations relies on accurate estimates of mineral weathering rates that are not widely available. In this study, bulk atmospheric deposition, surface water and soil chemistry along with 87 Sr/ 86 Sr isotope measurements were used to provide regional insight into weathering controls on Ca concentrations in lakes. Regionally, Ca concentrations in 90% of 129 lakes sampled in central Ontario were <0.1 mmol L -1 and the Ca/Sr ratio in lakes increased and the K/Sr ratio decreased with increasing Sr concentration, which is indicative of greater Ca sources from calcite or apatite in the higher Ca lakes. Significant relationships between 87 Sr/ 86 Sr ratios and Ca/Sr rations in dilute acid (0.1 M HCl) soil extracts are also indicative of the presence of trace amounts of calcite or apatite in surficial soils. Within the low (<0.7 mmol L -1 ) Ca lakes, defined in this study that are considered most at risk from falling Ca concentrations, 87 Sr/ 86 Sr ratios fell within the range observed in weak acid soil extracts and were also significantly related to Ca/Na and K/Sr ratios in surface waters. There were large inconsistencies however, between Ca/Na ratios and Ca/Sr in surface waters and soil acid extracts that suggest differences in 87 Sr/ 86 Sr ratios in surface waters of the low Ca lakes do not simply reflect differences in Ca derived from non-silicate minerals in surficial soils and that that Ca sources from deeper soil or bedrock are also important contributors to surface water Ca in these low Ca lakes. Copyright © 2018 Elsevier B.V. All rights reserved.

RadNet Air Data From Las Vegas, NV

EPA Pesticide Factsheets

This page presents radiation air monitoring and air filter analysis data for Las Vegas, NV from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

Lake warming favours small-sized planktonic diatom species

PubMed Central

Winder, Monika; Reuter, John E.; Schladow, S. Geoffrey

2008-01-01

Diatoms contribute to a substantial portion of primary production in the oceans and many lakes. Owing to their relatively heavy cell walls and high nutrient requirements, planktonic diatoms are expected to decrease with climate warming because of reduced nutrient redistribution and increasing sinking velocities. Using a historical dataset, this study shows that diatoms were able to maintain their biovolume with increasing stratification in Lake Tahoe over the last decades; however, the diatom community structure changed. Increased stratification and reduced nitrogen to phosphorus ratios selected for small-celled diatoms, particularly within the Cyclotella genus. An empirical model showed that a shift in phytoplankton species composition and cell size was consistent within different depth strata, indicating that altered nutrient concentrations were not responsible for the change. The increase in small-celled species was sufficient to decrease the average diatom size and thus sinking velocity, which strongly influences energy transfer through the food web and carbon cycling. Our results show that within the diverse group of diatoms, small-sized species with a high surface area to volume ratio were able to adapt to a decrease in mixing intensity, supporting the hypotheses that abiotic drivers affect the size structure of planktonic communities and that warmer climate favours small-sized diatom cells. PMID:18812287

The jellification of north temperate lakes.

PubMed

Jeziorski, Adam; Tanentzap, Andrew J; Yan, Norman D; Paterson, Andrew M; Palmer, Michelle E; Korosi, Jennifer B; Rusak, James A; Arts, Michael T; Keller, Wendel Bill; Ingram, Ron; Cairns, Allegra; Smol, John P

2015-01-07

Calcium (Ca) concentrations are decreasing in softwater lakes across eastern North America and western Europe. Using long-term contemporary and palaeo-environmental field data, we show that this is precipitating a dramatic change in Canadian lakes: the replacement of previously dominant pelagic herbivores (Ca-rich Daphnia species) by Holopedium glacialis, a jelly-clad, Ca-poor competitor. In some lakes, this transformation is being facilitated by increases in macro-invertebrate predation, both from native (Chaoborus spp.) and introduced (Bythotrephes longimanus) zooplanktivores, to which Holopedium, with its jelly coat, is relatively invulnerable. Greater representation by Holopedium within cladoceran zooplankton communities will reduce nutrient transfer through food webs, given their lower phosphorus content relative to daphniids, and greater absolute abundances may pose long-term problems to water users. The dominance of jelly-clad zooplankton will likely persist while lakewater Ca levels remain low. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Characterizing the Fate and Mobility of Phosphorus in Utah Lake Sediments

NASA Astrophysics Data System (ADS)

Carling, G. T.; Randall, M.; Nelson, S.; Rey, K.; Hansen, N.; Bickmore, B.; Miller, T.

2017-12-01

An increasing number of lakes worldwide are impacted by eutrophication and harmful algal blooms due to anthropogenic nutrient inputs. Utah Lake is a unique eutrophic freshwater lake that is naturally shallow, turbid, and alkaline with high dissolved oxygen levels that has experienced severe algal blooms in recent years. Recently, the Utah Division of Water Quality has proposed a new limitation of phosphorus (P) loading to Utah Lake from wastewater treatment plants in an effort to mitigate eutrophication. However, reducing external P loads may not lead to immediate improvements in water quality due to the legacy pool of nutrients in lake sediments. The purpose of this study was to characterize the fate and mobility of P in Utah Lake sediments to better understand P cycling in this unique system. We analyzed P speciation, mineralogy, and binding capacity in lake sediment samples collected from 15 locations across Utah Lake. P concentrations in sediment ranged from 615 to 1894 ppm, with highest concentrations in Provo Bay near the major metropolitan area. Sequential leach tests indicate that 25-50% of P is associated with Ca (CaCO₃/ Ca10(PO4)6(OH,F,Cl)2 ≈ P) and 40-60% is associated with Fe (Fe(OOH) ≈ P). Ca-associated P was confirmed by SEM images, which showed the highest P concentrations correlating with Ca (carbonate minerals/apatite). The Ca-associated P fraction is likely immobile, but the Fe-bound P is potentially bioavailable under changing redox conditions. Batch sorption results indicate that lake sediments have a high capacity to absorb and remove P from the water column, with an average uptake of 70-96% removal over the range of 1-10 mg/L P. Mineral precipitation and sorption to bottom sediments is an efficient removal mechanism of P in Utah Lake, but a significant portion of P may be temporarily available for resuspension and cycling in surface waters. Mitigating lake eutrophication is a complex problem that goes beyond decreasing external nutrient

The carbon cycle and biogeochemical dynamics in lake sediments

USGS Publications Warehouse

Dean, W.E.

1999-01-01

The concentrations of organic carbon (OC) and CaCO3 in lake sediments are often inversely related. This relation occurs in surface sediments from different locations in the same lake, surface sediments from different lakes, and with depth in Holocene sediments. Where data on accumulation rates are available, the relation holds for organic carbon and CaCO3 accumulation rates as well. An increase of several percent OC is accompanied by a decrease of several tens of percent CaCO3 indicating that the inverse relation is not due to simple dilution of one component by another. It appears from core data that once the OC concentration in the sediments becomes greater than about 12%, the CO2 produced by decomposition of that OC and production of organic acids lowers the pH of anoxic pore waters enough to dissolve any CaCO3 that reaches the sediment-water interface. In a lake with a seasonally anoxic hypolimnion, processes in the water column also can produce an inverse relation between OC and CaCO3 over time. If productivity of the lake increases, the rain rate of OC from the epilimnion increases. Biogenic removal of CO2 and accompanying increase in pH also may increase the production of CaCO3. However, the decomposition of organic matter in the hypolimnion will decrease the pH of the hypolimnion causing greater dissolution of CaCO3 and therefore a decrease in the rain rate of CaCO3 to the sediment-water interface.

Degradation of [Dha7]MC-LR by a Microcystin Degrading Bacterium Isolated from Lake Rotoiti, New Zealand

PubMed Central

Somdee, Theerasak; Ruck, John; Lys, Isabelle; Allison, Margaret; Page, Rachel

2013-01-01

For the first time a microcystin-degrading bacterium (NV-3 isolate) has been isolated and characterized from a NZ lake. Cyanobacterial blooms in New Zealand (NZ) waters contain microcystin (MC) hepatotoxins at concentrations which are a risk to animal and human health. Degradation of MCs by naturally occurring bacteria is an attractive bioremediation option for removing MCs from drinking and recreational water sources. The NV-3 isolate was identified by 16S rRNA sequence analysis and found to have 100% nucleotide sequence homology with the Sphingomonas MC-degrading bacterial strain MD-1 from Japan. The NV-3 isolate (concentration of 1.0 × 108 CFU/mL) at 30°C degraded a mixture of [Dha7]MC-LR and MC-LR (concentration 25 μg/mL) at a maximum rate of 8.33 μg/mL/day. The intermediate by-products of [Dha7]MC-LR degradation were detected and similar to MC-LR degradation by-products. The presence of three genes (mlrA, mlrB, and mlrC), that encode three enzymes involved in the degradation of MC-LR, were identified in the NV-3 isolate. This study confirmed that degradation of [Dha7]MC-LR by the Sphingomonas isolate NV-3 occurred by a similar mechanism previously described for MC-LR by Sphingomonas strain MJ-PV (ACM-3962). This has important implications for potential bioremediation of toxic blooms containing a variety of MCs in NZ waters. PMID:23936728

Vertical redistribution of zooplankton in an oligotrophic lake associated with reduction in ultraviolet radiation by wildfire smoke

NASA Astrophysics Data System (ADS)

Urmy, Samuel S.; Williamson, Craig E.; Leach, Taylor H.; Schladow, S. Geoffrey; Overholt, Erin P.; Warren, Joseph D.

2016-04-01

We used a natural experiment to test whether wildfire smoke induced changes in the vertical distribution of zooplankton in Lake Tahoe by decreasing incident ultraviolet radiation (UV). Fires have a variety of effects on aquatic ecosystems, but these impacts are poorly understood and have rarely been observed directly. UV is an important driver of zooplankton vertical migration, and wildfires may alter it over large spatial scales. We measured UV irradiance and the distribution of zooplankton on two successive days. On one day, smoke haze from a nearby wildfire reduced incident UV radiation by up to 9%, but not irradiance in the visible spectrum. Zooplankton responded by positioning themselves, on average, 4.1 m shallower in the lake. While a limited data set such as this requires cautious interpretation, our results suggest that smoke from wildfires can change the UV environment and distribution of zooplankton. This process may be important in drought-prone regions with increasingly frequent wildfires, and globally due to widespread biomass burning.

Hybrid photonic crystal cavity and waveguide for coupling to diamond NV-centers.

PubMed

Barclay, Paul E; Fu, Kai-Mei; Santori, Charles; Beausoleil, Raymond G

2009-06-08

A design for an ultra-high Q photonic crystal nanocavity engineered to interact with nitrogen-vacancy (NV) centers located near the surface of a single crystal diamond sample is presented. The structure is based upon a nanowire photonic crystal geometry, and consists of a patterned high refractive index thin film, such as gallium phosphide (GaP), supported by a diamond substrate. The nanocavity supports a mode with quality factor Q > 1.5 x 10(6) and mode volume V < 0.52(lambda/nGaP)(3), and promises to allow Purcell enhanced collection of spontaneous emission from an NV located more than 50 nm below the diamond surface. The nanowire photonic crystal waveguide can be used to efficiently couple light into and out of the cavity, or as an efficient broadband collector of NV phonon sideband emission. The proposed structures can be fabricated using existing materials and processing techniques.

NV Energy Electricity Storage Valuation

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

Ellison, James F.; Bhatnagar, Dhruv; Samaan, Nader A.

2013-06-30

This study examines how grid-level electricity storage may benet the operations of NV Energy in 2020, and assesses whether those benets justify the cost of the storage system. In order to determine how grid-level storage might impact NV Energy, an hourly production cost model of the Nevada Balancing Authority (\\BA") as projected for 2020 was built and used for the study. Storage facilities were found to add value primarily by providing reserve. Value provided by the provision of time-of-day shifting was found to be limited. If regulating reserve from storage is valued the same as that from slower ramp ratemore » resources, then it appears that a reciprocating engine generator could provide additional capacity at a lower cost than a pumped storage hydro plant or large storage capacity battery system. In addition, a 25-MW battery storage facility would need to cost $650/kW or less in order to produce a positive Net Present Value (NPV). However, if regulating reserve provided by storage is considered to be more useful to the grid than that from slower ramp rate resources, then a grid-level storage facility may have a positive NPV even at today's storage system capital costs. The value of having storage provide services beyond reserve and time-of-day shifting was not assessed in this study, and was therefore not included in storage cost-benefit calculations.« less

Non-intrusive tunable resonant microwave cavity for optical detected magnetic resonance of NV centres in nanodiamonds

NASA Astrophysics Data System (ADS)

Le Floch, Jean-Michel; Bradac, Carlo; Volz, Thomas; Tobar, Michael E.; Castelletto, Stefania

2013-12-01

Optically detected magnetic resonance (ODMR) in nanodiamond nitrogen-vacancy (NV) centres is usually achieved by applying a microwave field delivered by micron-size wires, strips or antennas directly positioned in very close proximity (~ μm) of the nanodiamond crystals. The microwave field couples evanescently with the ground state spin transition of the NV centre (2.87 GHz at zero magnetic field), which results in a reduction of the centre photoluminescence. We propose an alternative approach based on the construction of a dielectric resonator. We show that such a resonator allows for the efficient detection of NV spins in nanodiamonds without the constraints associated to the laborious positioning of the microwave antenna next to the nanodiamonds, providing therefore improved flexibility. The resonator is based on a tunable Transverse Electric Mode in a dielectric-loaded cavity, and we demonstrate that the resonator can detect single NV centre spins in nanodiamonds using less microwave power than alternative techniques in a non-intrusive manner. This method can achieve higher precision measurement of ODMR of paramagnetic defects spin transition in the micro to millimetre-wave frequency domain. Our approach would permit the tracking of NV centres in biological solutions rather than simply on the surface, which is desirable in light of the recently proposed applications of using nanodiamonds containing NV centres for spin labelling in biological systems with single spin and single particle resolution.

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

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

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.

Molecular characterization of the Great Lakes viral hemorrhagic septicemia virus (VHSV) isolate from USA

PubMed Central

Ammayappan, Arun; Vakharia, Vikram N

2009-01-01

Background Viral hemorrhagic septicemia virus (VHSV) is a highly contagious viral disease of fresh and saltwater fish worldwide. VHSV caused several large scale fish kills in the Great Lakes area and has been found in 28 different host species. The emergence of VHS in the Great Lakes began with the isolation of VHSV from a diseased muskellunge (Esox masquinongy) caught from Lake St. Clair in 2003. VHSV is a member of the genus Novirhabdovirus, within the family Rhabdoviridae. It has a linear single-stranded, negative-sense RNA genome of approximately 11 kbp, with six genes. VHSV replicates in the cytoplasm and produces six monocistronic mRNAs. The gene order of VHSV is 3'-N-P-M-G-NV-L-5'. This study describes molecular characterization of the Great Lakes VHSV strain (MI03GL), and its phylogenetic relationships with selected European and North American isolates. Results The complete genomic sequences of VHSV-MI03GL strain was determined from cloned cDNA of six overlapping fragments, obtained by RT-PCR amplification of genomic RNA. The complete genome sequence of MI03GL comprises 11,184 nucleotides (GenBank GQ385941) with the gene order of 3'-N-P-M-G-NV-L-5'. These genes are separated by conserved gene junctions, with di-nucleotide gene spacers. The first 4 nucleotides at the termini of the VHSV genome are complementary and identical to other novirhadoviruses genomic termini. Sequence homology and phylogenetic analysis show that the Great Lakes virus is closely related to the Japanese strains JF00Ehi1 (96%) and KRRV9822 (95%). Among other novirhabdoviruses, VHSV shares highest sequence homology (62%) with snakehead rhabdovirus. Conclusion Phylogenetic tree obtained by comparing 48 glycoprotein gene sequences of different VHSV strains demonstrate that the Great Lakes VHSV is closely related to the North American and Japanese genotype IVa, but forms a distinct genotype IVb, which is clearly different from the three European genotypes. Molecular characterization of the

Organic geochemistry and brine composition in Great Salt, Mono, and Walker Lakes

USGS Publications Warehouse

Domagalski, Joseph L.; Orem, W.H.; Eugster, H.P.

1989-01-01

Samples of Recent sediments, representing up to 1000 years of accumulation, were collected from three closed basin lakes (Mono Lake, CA, Walker Lake, NV, and Great Salt Lake, UT) to assess the effects of brine composition on the accumulation of total organic carbon, the concentration of dissolved organic carbon, humic acid structure and diagenesis, and trace metal complexation. The Great Salt Lake water column is a stratified Na-Mg-Cl-SO4 brine with low alkalinity. Algal debris is entrained in the high density (1.132-1.190 g/cc) bottom brines, and in this region maximum organic matter decomposition occurs by anaerobic processes, with sulfate ion as the terminal electron acceptor. Organic matter, below 5 cm of the sediment-water interface, degrades at a very slow rate in spite of very high pore-fluid sulfate levels. The organic carbon concentration stabilizes at 1.1 wt%. Mono Lake is an alkaline (Na-CO3-Cl-SO4) system. The water column is stratified, but the bottom brines are of lower density relative to the Great Salt Lake, and sedimentation of algal debris is rapid. Depletion of pore-fluid sulfate, near l m of core, results in a much higher accumulation of organic carbon, approximately 6 wt%. Walker Lake is also an alkaline system. The water column is not stratified, and decomposition of organic matter occurs by aerobic processes at the sediment-water interface and by anaerobic processes below. Total organic carbon and dissolved organic carbon concentrations in Walker Lake sediments vary with location and depth due to changes in input and pore-fluid sulfate concentrations. Nuclear magnetic resonance studies (13C) of humic substances and dissolved organic carbon provide information on the source of the Recent sedimentary organic carbon (aquatic vs. terrestrial), its relative state of decomposition, and its chemical structure. The spectra suggest an algal origin with little terrestrial signature at all three lakes. This is indicated by the ratio of aliphatic to

Arsenic Removal from Drinking Water by Adsorptive Media U.S. EPA Demonstration Project at Upper Bodfish in Lake Isabella, CA Interim Evaluation Report

EPA Science Inventory

This report documents the activities performed during and the results obtained from the first 10 months of system operation of an arsenic (As) and uranium (U) removal technology being demonstrated at Upper Bodfish in Lake Isabella, CA. The objectives of the project are to evalua...

77 FR 45331 - Humboldt (NV) Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-31

... Act. The purpose is to review Title II funding procedures and Humboldt (NV) RAC operating guidelines..., Winnemucca, Nevada. Written comments should be sent to USDA Forest Service, 1500 E Winnemucca Blvd... between 8:00 a.m. and 8:00 p.m., Eastern Standard Time, Monday through Friday. SUPPLEMENTARY INFORMATION...

Scalable fabrication of coupled NV center - photonic crystal cavity systems by self-aligned N ion implantation

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

Schröder, T.; Walsh, M.; Zheng, J.

2017-04-06

Towards building large-scale integrated photonic systems for quantum information processing, spatial and spectral alignment of single quantum systems to photonic nanocavities is required. In this paper, we demonstrate spatially targeted implantation of nitrogen vacancy (NV) centers into the mode maximum of 2-d diamond photonic crystal cavities with quality factors up to 8000, achieving an average of 1.1 ± 0.2 NVs per cavity. Nearly all NV-cavity systems have significant emission intensity enhancement, reaching a cavity-fed spectrally selective intensity enhancement, F int, of up to 93. Although spatial NV-cavity overlap is nearly guaranteed within about 40 nm, spectral tuning of the NV’smore » zero-phonon-line (ZPL) is still necessary after fabrication. To demonstrate spectral control, we temperature tune a cavity into an NV ZPL, yielding F ZPL int~5 at cryogenic temperatures.« less

Lake ecosystem response to rapid lateglacial climate changes in lake sediments from northern Poland

NASA Astrophysics Data System (ADS)

Słowiński, Michał; Zawiska, Izabela; Ott, Florian; Noryśkiewicz, Agnieszka M.; Apolinarska, Karina; Lutyńska, Monika; Michczyńska, Danuta J.; Brauer, Achim; Wulf, Sabine; Skubała, Piotr; Błaszkiewicz, Mirosław

2013-04-01

During the Late Glacial Period environment changes were triggered by climatic oscillations which in turn controlled processes like, for example, permafrost thawing, vegetation development and ground water circulation. These environmental changes are ideally recorded in lake sediments and thus can be reconstructed applying a multi-poxy approach. Here, we present the results from the Trzechowskie paleolake, located in the northern Polish lowlands (eastern part of the Pomeranian Lakeland). The site is situated on the outwash plain of the Wda River, which was formed during the Pomeranian phase of the Vistulian glaciation ca 16,000 14C yrs BP. The depression of the Trzechowskie lake basin formed after melting of a buried ice block during the Allerød (13903±170 cal yrs BP). We reconstructed environmental changes in the Trzechowskie paleolake and its catchment using biotic proxies (macrofossils, pollen, cladocera, diatoms, oribatidae mite) and geochemical proxies (δ18O, δ13C, loss-on-ignition (LOI), CaCO3 content). In addition, we carried out µ-XRF element core scanning. The chronology has been established by means of biostratigraphyAMS14C dating on plant macro remains, varve counting in laminated intervals and the late Allerød Laacher See Tephra isochrone. Our results showed that biogenic accumulation in the lake started during the Bølling. Development of coniferous forest during the Allerød with dominance of Pinus sylvestris lead to leaching of carbonates in the catchment due to low pH increasing the flux of Ca ions into the lake. In consequence calcite precipitating in the lake increased as evidences by increasing CaCO3 contents. Both biotic and physical proxies clearly reflect the rapid decrease in productivity at the onset of the Younger Dryas. We compare the data from the Trzechowskie paleolake with the Meerfelder Maar and Rehwiese lake records based on tephrochronological synchronization using the Laacher See Tephra. This study is a contribution to the

77 FR 38476 - Establishment of Class E Airspace; Eureka, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-28

... (GPS) standard instrument approach procedures at Eureka Airport, Eureka, NV. This improves the safety... Eureka Airport, to accommodate IFR aircraft executing a new RNAV (GPS) standard instrument approach...

NV-CMOS HD camera for day/night imaging

NASA Astrophysics Data System (ADS)

Vogelsong, T.; Tower, J.; Sudol, Thomas; Senko, T.; Chodelka, D.

2014-06-01

SRI International (SRI) has developed a new multi-purpose day/night video camera with low-light imaging performance comparable to an image intensifier, while offering the size, weight, ruggedness, and cost advantages enabled by the use of SRI's NV-CMOS HD digital image sensor chip. The digital video output is ideal for image enhancement, sharing with others through networking, video capture for data analysis, or fusion with thermal cameras. The camera provides Camera Link output with HD/WUXGA resolution of 1920 x 1200 pixels operating at 60 Hz. Windowing to smaller sizes enables operation at higher frame rates. High sensitivity is achieved through use of backside illumination, providing high Quantum Efficiency (QE) across the visible and near infrared (NIR) bands (peak QE <90%), as well as projected low noise (<2h+) readout. Power consumption is minimized in the camera, which operates from a single 5V supply. The NVCMOS HD camera provides a substantial reduction in size, weight, and power (SWaP) , ideal for SWaP-constrained day/night imaging platforms such as UAVs, ground vehicles, fixed mount surveillance, and may be reconfigured for mobile soldier operations such as night vision goggles and weapon sights. In addition the camera with the NV-CMOS HD imager is suitable for high performance digital cinematography/broadcast systems, biofluorescence/microscopy imaging, day/night security and surveillance, and other high-end applications which require HD video imaging with high sensitivity and wide dynamic range. The camera comes with an array of lens mounts including C-mount and F-mount. The latest test data from the NV-CMOS HD camera will be presented.

GaN Nanowire Arrays for Efficient Optical Read-Out and Optoelectronic Control of NV Centers in Diamond.

PubMed

Hetzl, Martin; Wierzbowski, Jakob; Hoffmann, Theresa; Kraut, Max; Zuerbig, Verena; Nebel, Christoph E; Müller, Kai; Finley, Jonathan J; Stutzmann, Martin

2018-06-13

Solid-state quantum emitters embedded in a semiconductor crystal environment are potentially scalable platforms for quantum optical networks operated at room temperature. Prominent representatives are nitrogen-vacancy (NV) centers in diamond showing coherent entanglement and interference with each other. However, these emitters suffer from inefficient optical outcoupling from the diamond and from fluctuations of their charge state. Here, we demonstrate the implementation of regular n-type gallium nitride nanowire arrays on diamond as photonic waveguides to tailor the emission direction of surface-near NV centers and to electrically control their charge state in a p-i-n nanodiode. We show that the electrical excitation of single NV centers in such a diode can efficiently replace optical pumping. By the engineering of the array parameters, we find an optical read-out efficiency enhanced by a factor of 10 and predict a lateral NV-NV coupling 3 orders of magnitude stronger through evanescently coupled nanowire antennas compared to planar diamond not covered by nanowires, which opens up new possibilities for large-scale on-chip quantum-computing applications.

A New Polysulfone Membrane Dialyzer, NV, with Low-Fouling and Antithrombotic Properties.

PubMed

Oshihara, Wataru; Ueno, Yoshiyuki; Fujieda, Hiroaki

2017-01-01

The biggest problem in routine hemodialysis therapy is possibly the blood pressure fall experienced by patients during dialysis. In contrast, in medium- and long-term hemodialysis therapy, the main problem might be deterioration of arteriosclerosis because of medial calcification associated with dialysis vintage. Both problems are caused by an autonomic imbalance or structural change in the blood vessels. Inflammation due to extracorporeal blood circulation is another possible cause. This inflammation is considered to cause platelets activated by contact and adherence with the membrane surface to aggregate with white blood cells and attack the endothelium of the blood vessels. Therefore, we tried to develop a new membrane with no adsorption and no platelet activation. Polysulfone (PS) membranes with polyvinylpyrrolidone (PVP) as a hydrophilic agent are widely used in dialysis, but blood components adhere to the membrane surface. We developed a new dialyzer, NV, by localizing a new hydrophilic polymer onto the inner surface of a hollow-fiber membrane composed of PS and PVP. The number of platelets that adhered to the NV membrane surface drastically decreased to 0.9% of that with the conventional PS dialysis membrane. We also confirmed the mechanism by which NV realizes clinical improvements in blood pressure drops and inflammation during dialysis, and verified its clinical appeal. Key Messages: The new membrane NV, which inhibits platelet adhesion and is compatible with blood vessels, is clinically beneficial. © 2017 S. Karger AG, Basel.

Extending WEPP technology to predict fine sediment and phosphorus delivery from forested hillslopes

Treesearch

William Elliot; Erin Brooks; Drea Em Traeumer; Mariana Dobre

2015-01-01

In many watersheds, including the Great Lakes and Lake Tahoe Basins, two basins where the land cover is dominated by forests, the pollutants of concern are fine sediments and phosphorus. Forest runoff is generally low in nitrogen, and coarse sediment does not adversely impact the quality of lake waters. Predictive tools are needed to estimate not simply sediment, but...

78 FR 7426 - City of Fallon, Nevada; Truckee Donner Public Utility District v. NV Energy Operating Companies...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-01

... Zone A imbalance provisions of their open access transmission tariff (NV Energy OATT) and (2) should replace the imbalance provisions currently reflected in Schedules 4 and 9 of the NV Energy OATT, with the...

Characterization of NvLWamide-like neurons reveals stereotypy in Nematostella nerve net development.

PubMed

Havrilak, Jamie A; Faltine-Gonzalez, Dylan; Wen, Yiling; Fodera, Daniella; Simpson, Ayanna C; Magie, Craig R; Layden, Michael J

2017-11-15

The organization of cnidarian nerve nets is traditionally described as diffuse with randomly arranged neurites that show minimal reproducibility between animals. However, most observations of nerve nets are conducted using cross-reactive antibodies that broadly label neurons, which potentially masks stereotyped patterns produced by individual neuronal subtypes. Additionally, many cnidarians species have overt structures such as a nerve ring, suggesting higher levels of organization and stereotypy exist, but mechanisms that generated that stereotypy are unknown. We previously demonstrated that NvLWamide-like is expressed in a small subset of the Nematostella nerve net and speculated that observing a few neurons within the developing nerve net would provide a better indication of potential stereotypy. Here we document NvLWamide-like expression more systematically. NvLWamide-like is initially expressed in the typical neurogenic salt and pepper pattern within the ectoderm at the gastrula stage, and expression expands to include endodermal salt and pepper expression at the planula larval stage. Expression persists in both ectoderm and endoderm in adults. We characterized our NvLWamide-like::mCherry transgenic reporter line to visualize neural architecture and found that NvLWamide-like is expressed in six neural subtypes identifiable by neural morphology and location. Upon completing development the numbers of neurons in each neural subtype are minimally variable between animals and the projection patterns of each subtype are consistent. Furthermore, between the juvenile polyp and adult stages the number of neurons for each subtype increases. We conclude that development of the Nematostella nerve net is stereotyped between individuals. Our data also imply that one aspect of generating adult cnidarian nervous systems is to modify the basic structural architecture generated in the juvenile by increasing neural number proportionally with size. Copyright © 2017 The Authors

NV centers in 3 C ,4 H , and 6 H silicon carbide: A variable platform for solid-state qubits and nanosensors

NASA Astrophysics Data System (ADS)

von Bardeleben, H. J.; Cantin, J. L.; Csóré, A.; Gali, A.; Rauls, E.; Gerstmann, U.

2016-09-01

The outstanding magneto-optical properties of the nitrogen-vacancy (NV) center in diamond have stimulated the search for similar systems. We show here that NV triplet centers can also be generated in all the main SiC polytypes. We have identified by electron paramagnetic resonance spectroscopy and first-principles calculations the axial NV- pairs in 3 C ,4 H , and 6 H SiC, showing polytype and lattice site-specific magnetic and optical properties. We demonstrate very efficient room-temperature spin polarization of the ground state upon near infrared optical excitation for the NV center in 3 C SiC and axial NV centers in the hexagonal (4 H ,6 H ) polytypes; the signals of basal pairs are much lower in intensity. Axial NV centers in hexagonal SiC polytypes and thus constitute unidirectional ensembles which may be useful in nanosensing applications.

77 FR 59374 - Foreign-Trade Zone 126-Reno, NV, Withdrawal of Production Notification, Brightpoint North America...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-27

... DEPARTMENT OF COMMERCE Foreign-Trade Zones Board [Docket B-37-2012] Foreign-Trade Zone 126--Reno, NV, Withdrawal of Production Notification, Brightpoint North America L.P. (Cell Phone Kitting and Distribution), Reno, NV Notice is hereby given of the withdrawal of the notification of the Economic...

The glacial/deglacial history of sedimentation in Bear Lake, Utah and Idaho

USGS Publications Warehouse

Rosenbaum, J.G.; Heil, C.W.

2009-01-01

Bear Lake, in northeastern Utah and southern Idaho, lies in a large valley formed by an active half-graben. Bear River, the largest river in the Great Basin, enters Bear Lake Valley ???15 km north of the lake. Two 4-m-long cores provide a lake sediment record extending back ???26 cal k.y. The penetrated section can be divided into a lower unit composed of quartz-rich clastic sediments and an upper unit composed largely of endogenic carbonate. Data from modern fluvial sediments provide the basis for interpreting changes in provenance of detrital material in the lake cores. Sediments from small streams draining elevated topography on the east and west sides of the lake are characterized by abundant dolomite, high magnetic susceptibility (MS) related to eolian magnetite, and low values of hard isothermal remanent magnetization (HIRM, indicative of hematite content). In contrast, sediments from the headwaters of the Bear River in the Uinta Mountains lack carbonate and have high HIRM and low MS. Sediments from lower reaches of the Bear River contain calcite but little dolomite and have low values of MS and HIRM. These contrasts in catchment properties allow interpretation of the following sequence from variations in properties of the lake sediment: (1) ca. 26 cal ka-onset of glaciation; (2) ca. 26-20 cal ka-quasicyclical, millennial-scale variations in the concentrations of hematite-rich glacial fl our derived from the Uinta Mountains, and dolomite- and magnetite-rich material derived from the local Bear Lake catchment (reflecting variations in glacial extent); (3) ca. 20-19 cal ka-maximum content of glacial fl our; (4) ca. 19-17 cal ka-constant content of Bear River sediment but declining content of glacial fl our from the Uinta Mountains; (5) ca. 17-15.5 cal ka-decline in Bear River sediment and increase in content of sediment from the local catchment; and (6) ca. 15.5-14.5 cal ka-increase in content of endogenic calcite at the expense of detrital material. The onset

Matuyama/Brunhes Polarity Transition in Owens Lake, CA, Sediment

NASA Astrophysics Data System (ADS)

Liddicoat, Joseph; Kravchinsky, Vadim

2014-05-01

The complexity of the Matuyama/Brunhes (M/B) polarity transition is becoming better understood from investigations of volcanic rocks (Coe et al., 2004), loess (Jin et al., 2012; Evans et al., 2011; Kravchinsky, 2013), and marine (Clement and Opdyke, 1982; Hartl and Tauxe, 1996; Macri et al., 2010) and lacustrine (Valet et al., 1988; Sagnotti et al., 2013) sediments. The transition appears to include a brief interval of normal polarity prior to the entry into the Brunhes Normal Chron (Coe et al., 2004; Jin et al., 2012; Evans et al., 2011), and the transition has Virtual Geomagnetic Poles rapidly moving from the Southern Hemisphere to the Northern Hemisphere (Coe et al., 2004; Jin et al., 2012; Evans et al., 2011; Sagnotti et al., 2013). The M/B polarity transition is recorded in exposed Pleistocene lake sediments near Bishop, CA, where the brief interval of normal polarity noted above is present and the change from full reverse to full normal polarity occurs rapidly. The brief interval of normal polarity is recorded at two sites separated laterally by about 150 m and is in single hand samples measured at vertical spacing of 2.0-2.5 cm using six samples per measured level and alternating field demagnetization at 20 mT (Liddicoat, 1993, Table 1 and Fig. 8). The siltstone is unweathered glacial flour from the Sierra Nevada that borders the western side of Owens Valley where the sediments were deposited in Owens Lake. In the siltstone, the majority of the samples have a percentage of about 60 percent where the grain diameter is less than 63 micrometres, and in those samples there is about a five percent fraction when the diameter is two micrometres or less. The Total Inorganic Carbon in most samples is about 0.25 percent (Bergeron, 2013), and magnetite is the dominant carrier of the magnetization (Liddicoat, 1993). The palaeomagnetic directions recording the terminus of the full M/B transition, which occurs before the field intensity is completely recovered, spans no

Radon Sampling, Building 54, Nellis AFB, NV

DTIC Science & Technology

2012-07-13

BEF) performed radon testing in response to a concern of elevated radon levels in Building 54. The building was previously remediated to reduce the... TESTING METHODOLOGY: a. Test Scenario: Building 54 was chosen to test for radon gas levels. Radon detectors were placed in the test ...Consultative Letter 3. DATES COVERED (From – To) 22-24 March 2012 4. TITLE AND SUBTITLE Radon Sampling, Building 54, Nellis AFB, NV 5a. CONTRACT

Sensitivity of fish density estimates to standard analytical procedures applied to Great Lakes hydroacoustic data

USGS Publications Warehouse

Kocovsky, Patrick M.; Rudstam, Lars G.; Yule, Daniel L.; Warner, David M.; Schaner, Ted; Pientka, Bernie; Deller, John W.; Waterfield, Holly A.; Witzel, Larry D.; Sullivan, Patrick J.

2013-01-01

Standardized methods of data collection and analysis ensure quality and facilitate comparisons among systems. We evaluated the importance of three recommendations from the Standard Operating Procedure for hydroacoustics in the Laurentian Great Lakes (GLSOP) on density estimates of target species: noise subtraction; setting volume backscattering strength (Sv) thresholds from user-defined minimum target strength (TS) of interest (TS-based Sv threshold); and calculations of an index for multiple targets (Nv index) to identify and remove biased TS values. Eliminating noise had the predictable effect of decreasing density estimates in most lakes. Using the TS-based Sv threshold decreased fish densities in the middle and lower layers in the deepest lakes with abundant invertebrates (e.g., Mysis diluviana). Correcting for biased in situ TS increased measured density up to 86% in the shallower lakes, which had the highest fish densities. The current recommendations by the GLSOP significantly influence acoustic density estimates, but the degree of importance is lake dependent. Applying GLSOP recommendations, whether in the Laurentian Great Lakes or elsewhere, will improve our ability to compare results among lakes. We recommend further development of standards, including minimum TS and analytical cell size, for reducing the effect of biased in situ TS on density estimates.

[Composition characteristics and source analysis of major ions in four small lake-watersheds on the Tibetan Plateau, China].

PubMed

Li, He; Li, Jun; Liu, Xiao-Long; Yang, Xi; Zhang, Wei; Wang, Jie; Niu, Ying-Quan

2015-02-01

To investigate the ionic compositions of small lake-watersheds on the Tibetan Plateau, water samples from the brackish lakes (Pung Co (lake), Angrenjin Co and Dajia Co), the freshwater lake (Daggyaima Co), their inflowing rivers and the hot spring (Dagejia Geothermal Field), were collected during July-August 2013. The results showed that the major anions and cations of the brackish lakes were HCO3-, SO4(2-) and Na+, respectively, and the hydrochemical types were HCO3-SO4-Na and HCO3-Na. The major anions and cations of the inflowing rivers and the freshwater lake were HCO3-, SO4(2-) and Ca2+, Mg2+, respectively, and the hydrochemical types were HCO3-Ca, HCO3-Ca-Mg, HCO3-Mg-Ca, HCO3-SO4-Ca and SO4-HCO3- Ca. The major anions and cations of the hot spring were HCO3- and Na+, respectively, and the hydrochemical type was HCO3-Na. Water chemistry in the brackish lakes was primarily dominated by evaporation-crystallization processes, while the inflowing rivers and the freshwater lake were mainly influenced by carbonate weathering, and the hot spring was mainly controlled by hot water-granite interaction. Ca2+ was preferentially removed over Mg2+ from the water when carbonate minerals precipitation occured, which resulted in the high Mg2+/Ca2+ molar ratios of the brackish lakes. In the contribution of cation compositions, the largest contribution was carbonate weathering (54% - 79%), followed by silicate weathering (13% -29%) and evaperite dissolution (4% -23%), and the smallest was atmospheric input (3% - 7%).

Palaeolimnological evidence of vulnerability of Lake Neusiedl (Austria) toward climate related changes since the last "vanished-lake" stage.

NASA Astrophysics Data System (ADS)

Tolotti, Monica; Milan, Manuela; Boscaini, Adriano; Soja, Gerhard; Herzig, Alois

2013-04-01

The palaeolimnological reconstruction of secular evolution of Euroepan Lakes with key socio-economical relevance respect to large (climate change) and local scale (land use, tourism) environmental changes, represents one of the objectives of the project EuLakes (European Lakes Under Environmental Stressors, Supporting lake governance to mitigate the impact of climate change, Reg. N. 2CE243P3), launched in 2010 within the Central European Inititiative. The project consortium comprises lakes of different morphology and prevalent human uses, including the meso-eutrophic Lake Neusiedl, the largest Austrian lake (total area 315 km2), and the westernmost shallow (mean depth 1.2 m) steppe lake of the Euro-Asiatic continent. The volume of Lake Neusiedl can potentially change over the years, in relation with changing balance between atmospheric precipitation and lake water evapotranspiration. Changing water budget, together with high lake salinity and turbidity, have important implications over the lake ecosystem. This contribution illustrates results of the multi-proxi palaeolimnological reconstruction of ecologial changes occurred in Lake Neusiedl during the last ca. 140 years, i.e. since the end of the last "vanished-lake" stage (1865-1871). Geochemical and biological proxies anticipate the increase in lake productivity of ca. 10 years (1950s) respect to what reported in the literature. Diatom species composition indicate a biological lake recovery in the late 1980s, and suggest a second increment in lake productivity since the late 1990s, possibly in relation with the progressive increase in the nitrogen input from agriculture. Abundance of diatoms typical of brackish waters indicated no significant long-term change in lake salinity, while variations in species toleranting dessiccation confirm the vulnerability of Lake Neusiedl toward climate-driven changes in the lake water balance. This fragility is aggravated by the the semi-arid climate conditions of the catchemnt

1. View of Lake Hodges Dam showing the origin of ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. View of Lake Hodges Dam showing the origin of the flume at left. View is looking east. - Lake Hodges Flume, Along San Dieguito River between Lake Hodges & San Dieguito Reservoir, Rancho Santa Fe, San Diego County, CA

40 CFR 51.917 - What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area?

Code of Federal Regulations, 2014 CFR

2014-07-01

... designation for the Las Vegas, NV, 8-hour ozone nonattainment area? 51.917 Section 51.917 Protection of... Air Quality Standard § 51.917 What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area? The Las Vegas, NV, 8-hour ozone nonattainment area (designated on September 17...

40 CFR 51.917 - What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area?

Code of Federal Regulations, 2010 CFR

2010-07-01

... designation for the Las Vegas, NV, 8-hour ozone nonattainment area? 51.917 Section 51.917 Protection of... Air Quality Standard § 51.917 What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area? The Las Vegas, NV, 8-hour ozone nonattainment area (designated on September 17...

40 CFR 51.917 - What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area?

Code of Federal Regulations, 2013 CFR

2013-07-01

... designation for the Las Vegas, NV, 8-hour ozone nonattainment area? 51.917 Section 51.917 Protection of... Air Quality Standard § 51.917 What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area? The Las Vegas, NV, 8-hour ozone nonattainment area (designated on September 17...

40 CFR 51.917 - What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area?

Code of Federal Regulations, 2011 CFR

2011-07-01

... designation for the Las Vegas, NV, 8-hour ozone nonattainment area? 51.917 Section 51.917 Protection of... Air Quality Standard § 51.917 What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area? The Las Vegas, NV, 8-hour ozone nonattainment area (designated on September 17...

40 CFR 51.917 - What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area?

Code of Federal Regulations, 2012 CFR

2012-07-01

... designation for the Las Vegas, NV, 8-hour ozone nonattainment area? 51.917 Section 51.917 Protection of... Air Quality Standard § 51.917 What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area? The Las Vegas, NV, 8-hour ozone nonattainment area (designated on September 17...

Particle count and black carbon measurements at schools in Las Vegas, NV and in the greater Salt Lake City, UT area.

PubMed

Brown, Steven G; Vaughn, David L; Roberts, Paul T

2017-11-01

As part of two separate studies aimed to characterize ambient pollutant concentrations at schools in urban areas, we compare black carbon and particle count measurements at Adcock Elementary in Las Vegas, NV (April-June 2013), and Hunter High School in the West Valley City area of greater Salt Lake City, UT (February 2012). Both schools are in urban environments, but Adcock Elementary is next to the U.S. 95 freeway. Black carbon (BC) concentrations were 13% higher at Adcock compared to Hunter, while particle count concentrations were 60% higher. When wind speeds were low-less than 2 m/sec-both BC and particle count concentrations were significantly higher at Adcock, while concentrations at Hunter did not have as strong a variation with wind speed. When wind speeds were less than 2 m/sec, emissions from the adjacent freeway greatly affected concentrations at Adcock, regardless of wind direction. At both sites, BC and particle count concentrations peaked in the morning during commute hours. At Adcock, particle count also peaked during midday or early afternoon, when BC was low and conditions were conducive to new particle formation. While this midday peak occurred at Adcock on roughly 45% of the measured days, it occurred on only about 25% of the days at Hunter, since conditions for particle formation (higher solar radiation, lower wind speeds, lower relative humidity) were more conducive at Adcock. Thus, children attending these schools are likely to be exposed to pollution peaks during school drop-off in the morning, when BC and particle count concentrations peak, and often again during lunchtime recess when particle count peaks again. Particle count concentrations at two schools were shown to typically be independent of BC or other pollutants. At a school in close proximity to a major freeway, particle count concentrations were high during the midday and when wind speeds were low, regardless of wind direction, showing a large area of effect from roadway emissions

Arsenic and Uranium Removal from Drinking Water by Adsorptive Media U.S. EPA Demonstration Project at Upper Bodfish in Lake Isabella, CA -Final Performance Evaluation Report

EPA Science Inventory

This report documents the activities performed during and the results obtained from the performance evaluation of an arsenic (As) and uranium (U) removal technology demonstrated at Upper Bodfish in Lake Isabella, CA. The objectives of the project are to evaluate: (1) the effecti...

The influence of landscape position on lake chemical responses to drought in northern Wisconsin

USGS Publications Warehouse

Webster, K.E.; Kratz, T.K.; Bowser, C.J.; Magnuson, J.J.; Rose, W.J.

1996-01-01

Climatic shifts to drier conditions during drought alter the hydrologic pathways of water and solute flow to aquatic ecosystems. We examined differences in drought-induced trends in the semiconservative cations, Ca+Mg, in seven northern Wisconsin lakes. These spanned the range of hydrologic settings in the region, including hydraulically mounded, groundwater flowthrough, and groundwater-discharge lakes. Parallel increases in concentration across the seven lakes during drought were attributable to evapoconcentration. However, we observed divergent trends for mass, which better reflects altered solute flux by accounting for changes in lake volume. Ca+Mg mass increased in three groundwater-dominated lakes as precipitation inputs were low and groundwater discharging from longer flowpaths became proportionately more important. In contrast, decreases in Ca+Mg mass for two precipitation-dominated lakes reflected diminished inputs of solute-rich groundwater. Landscape position, defined by the spatial position of a lake within a hydrologic flow system, accounted for the divergence in chemical responses to drought.

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.

Late quaternary sediments, minerals, and inferred geochemical history of Didwana Lake, Thar Desert, India

USGS Publications Warehouse

Wasson, R.J.; Smith, G.I.; Agrawal, D.P.

1984-01-01

Variations in clastic sediment texture, mineralogy of both evaporites formed at the surface and precipitates formed below the lake floor, and the relative chemical activities of the major dissolved components of the chemical precipitates, have allowed reconstruction of the history of salinity and water-level changes in Didwana Lake, Thar Desert, India. Hypersaline conditions prevailed at about the Last Glacial Maximum, with little evidence of clastic sediments entering the lake. Between ca. 13,000 and 6000 B.P. the lake level fluctuated widely, the lake alternately hypersaline and fresh, and clastic sediments were delivered to the lake at a low rate. Deep-water conditions occurred ca. 6000 B.P. and clastic influx increased abruptly. The water level dropped towards 4000 B.P. when the lake dried briefly. Since 4000 B.P. the lake has been ephemeral with a lowered rate of sedimentation and mildly saline conditions rather like those of today. This sequence of changes documented in the lake parallels changes in vegetation recorded in published pollen diagrams from both the Thar and the Arabian Sea. Correlation of the various lines of evidence suggests that the climate of the Last Glacial Maximum at Didwana was dry and windy with a weak monsson circulation. The monsson was re-established between ca. 13,000 and a little before 6000 B.P., and, when winter rainfall increased ca. 6000 B.P., the lake filled to its maximum depth. ?? 1984.

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

24. Lake Hodges Flume conduit enlargement. April 1930. Courtesy of ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

24. Lake Hodges Flume conduit enlargement. April 1930. Courtesy of the Mandeville Department of Special Collections, Central Library, University of California, San Diego. - Lake Hodges Flume, Along San Dieguito River between Lake Hodges & San Dieguito Reservoir, Rancho Santa Fe, San Diego County, CA

22. Concrete trestle on Lake Hodges Flume, 1919. Courtesy of ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

22. Concrete trestle on Lake Hodges Flume, 1919. Courtesy of the Mandeville Department of Special Collections, Central Library, University of California, San Diego. - Lake Hodges Flume, Along San Dieguito River between Lake Hodges & San Dieguito Reservoir, Rancho Santa Fe, San Diego County, CA

Chemical hazards from acid crater lakes

NASA Astrophysics Data System (ADS)

van Bergen, M. J.; Sumarti, S.; Heikens, A.; Bogaard, T. A.; Hartiyatun, S.

2003-04-01

Acid crater lakes, which are hosted by a considerable number of active volcanoes, form a potential threat for local ecosystems and human health, as they commonly contain large amounts of dissolved chemicals. Subsurface seepage or overflow can lead to severe deterioration of the water quality of rivers and wells, as observations around several of these volcanoes have shown. The Ijen crater lake in East Java (Indonesia) is a striking example, as this reservoir of hyperacid (pH<0.5) sulphate, chloride and fluoride-rich water is the source of a ca. 50 km long acid river that transports substantial quantities of potentially toxic elements. A downstream trend of increasing pH from <1 to 2.5-4 is largely due to dilution with moderately acid springs (pH= ca. 4) and neutral tributaries (pH= ca. 7) inside the Ijen caldera. Geochemical controls that regulate element transport are subject to seasonal fluctuations in rainfall. Long-term monitoring has shown that fluoride levels pose some of the most severe environmental threats. Its concentration decreases from ca. 1300 mg/kg in the lake to ca. 10 mg/kg in a coastal area downstream, where virtually all of the river water is used for irrigating rice fields and other cropland. Apart from serious problems for agriculture, our survey of 55 drinking water wells in the irrigation area shows that 50% contain fluoride above the 1.5 ppm WHO limit, in line with the observation that dental fluorosis is widespread among the ca. 100,000 residents of the area. A conspicuous spatial correlation between fluoride concentrations and the irrigation system suggest that long-term (century) infiltration of irrigation water may have affected the quality of groundwater. Fluorosis is also a problem in some villages within the caldera, where well water sources may have a more direct subsurface connection with the lake system. From our observations we conclude that water-quality monitoring is especially needed for health reasons in volcanic areas where

Anthropogenically driven changes in chloride complicate interpretation of base cation trends in lakes recovering from acidic deposition.

PubMed

Rosfjord, Catherine H; Webster, Katherine E; Kahl, Jeffrey S; Norton, Stephen A; Fernandez, Ivan J; Herlihy, Alan T

2007-11-15

Declines in Ca and Mg in low ANC lakes recovering from acidic deposition are widespread across the northern hemisphere. We report overall increases between 1984 and 2004 in the concentrations of Ca + Mg and Cl in lakes representing the statistical population of nearly 4000 low ANC lakes in the northeast U.S. Increases in Cl occurred in nearly all lakes in urbanized southern New England, but only 18% of lakes in more remote Maine had Cl increases. This spatial pattern implicates road salt application as the major source of the increased Cl salts. Among the 48% of the lake population classified as salt-affected, the median changes in Cl (+133 microeq/L) and Ca + Mg (+47 microeq/ L) were large and positive in direction over the 20 years. However, in the unaffected lakes, Cl remained stable and Ca + Mg decreased (-3 microeq/L), consistent with reported long-term trends in base cations of acid-sensitive lakes. This discrepancy between the Cl groups suggests that changes in ion exchange processes in salt-affected watersheds have altered the geochemical cycling of Ca and Mg. One policy-relevant implication is that waters influenced by Cl salts complicate regional assessments of surface water recovery from "acid rain" related to the passage of the Clean Air Act.

Towards quantum superposition of a levitated nanodiamond with a NV center

NASA Astrophysics Data System (ADS)

Li, Tongcang

2015-05-01

Creating large Schrödinger's cat states with massive objects is one of the most challenging goals in quantum mechanics. We have previously achieved an important step of this goal by cooling the center-of-mass motion of a levitated microsphere from room temperature to millikelvin temperatures with feedback cooling. To generate spatial quantum superposition states with an optical cavity, however, requires a very strong quadratic coupling that is difficult to achieve. We proposed to optically trap a nanodiamond with a nitrogen-vacancy (NV) center in vacuum, and generate large spatial superposition states using the NV spin-optomechanical coupling in a strong magnetic gradient field. The large spatial superposition states can be used to study objective collapse theories of quantum mechanics. We have optically trapped nanodiamonds in air and are working towards this goal.

δ18O and δD of lake waters across the Coast Range and Cascades, central Oregon: Modern insights from hydrologically open lakes into the control of landscape on lake water composition in deep time

NASA Astrophysics Data System (ADS)

Finkelstein, D. B.; Curtin, T.

2016-12-01

Reconstructing the stable isotopic composition of paleolake water normally requires an assumption of paleotemperature. However, hydrologically open paleolakes with short water residence times may have recorded paleoprecipitation along topographic gradients that are independent of lake water temperature. To identify the environmental and geographic controls on the isotopic composition of lake water, we sampled 22 natural lakes and reservoirs along a longitudinal and elevation gradient from the Pacific Ocean up and over the Coast and Cascade Ranges of central Oregon to the High Lava Plains in 2013 and 2015. The transect spans lakes of different origins, 6 geomorphic regions and an elevation range of 2-1942 m absl. The Coast Range lakes are sand hosted whereas the remaining are bedrock (volcanic and sedimentary) hosted. The lakes are hydrologically open and dominated by meteoric recharge. The water residence time ranges from months to decades. Samples were analyzed for temperature, pH, and total dissolved solids (TDS) in the field, and alkalinity and major cations and anions and stable isotopes of D and O in the lab. The pH ranges from 7 to 9.8 and shows no systematic variation based on substrate type or elevation. The lakes are dilute (avg. TDS = 35.8 ppm) and have low alkalinties (18.9 mg/L CaCO3) except for those in the High Lava Plains (avg. TDS = 337 ppm, alk: 291.2 mg/L CaCO3). In the Coast Range, Na is the major cation on an equivalent basis, reflecting proximity to the ocean. The easternmost lakes within the Coast Range are dominated by Ca, reflecting different drainage basins and substrate type. Lakes in the Western and High Cascades are dominated by Ca. The dominant cation and stable isotopic analyses clearly differentiate waters from different geomorphic regions. The δ18O ranges from -5.7 to -9.3 ‰ (VSMOW), and δD ranges from -37.8 to -63.6 ‰ (VSMOW) in the Coast Range whereas the δ18O ranges from -9.7 to -12.1 ‰ (VSMOW) and δD ranges from -71

21. Newly completed Lake Hodges Dam and Flume, 1919. Courtesy ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

21. Newly completed Lake Hodges Dam and Flume, 1919. Courtesy of the Mandeville Department of Special Collection, Central Library, University of California, San Diego. - Lake Hodges Flume, Along San Dieguito River between Lake Hodges & San Dieguito Reservoir, Rancho Santa Fe, San Diego County, CA

36 CFR 261.50 - Orders.

Code of Federal Regulations, 2011 CFR

2011-07-01

... in Areas Designated by Order § 261.50 Orders. (a) The Chief, each Regional Forester, each Experiment... Forester, each Experiment Station Director, the Administrator of the Lake Tahoe Basin Management Unit and...

36 CFR 261.50 - Orders.

Code of Federal Regulations, 2014 CFR

2014-07-01

... in Areas Designated by Order § 261.50 Orders. (a) The Chief, each Regional Forester, each Experiment... Forester, each Experiment Station Director, the Administrator of the Lake Tahoe Basin Management Unit and...

36 CFR 261.50 - Orders.

Code of Federal Regulations, 2012 CFR

2012-07-01

... in Areas Designated by Order § 261.50 Orders. (a) The Chief, each Regional Forester, each Experiment... Forester, each Experiment Station Director, the Administrator of the Lake Tahoe Basin Management Unit and...

36 CFR 261.50 - Orders.

Code of Federal Regulations, 2013 CFR

2013-07-01

... in Areas Designated by Order § 261.50 Orders. (a) The Chief, each Regional Forester, each Experiment... Forester, each Experiment Station Director, the Administrator of the Lake Tahoe Basin Management Unit and...

Late Quaternary sedimentary features of Bear Lake, Utah and Idaho

USGS Publications Warehouse

Smoot, J.P.

2009-01-01

Bear Lake sediments were predominantly aragonite for most of the Holocene, reflecting a hydrologically closed lake fed by groundwater and small streams. During the late Pleistocene, the Bear River flowed into Bear Lake and the lake waters spilled back into the Bear River drainage. At that time, sediment deposition was dominated by siliciclastic sediment and calcite. Lake-level fluctuation during the Holocene and late Pleistocene produced three types of aragonite deposits in the central lake area that are differentiated primarily by grain size, sorting, and diatom assemblage. Lake-margin deposits during this period consisted of sandy deposits including well-developed shoreface deposits on margins adjacent to relatively steep gradient lake floors and thin, graded shell gravel on margins adjacent to very low gradient lake-floor areas. Throughout the period of aragonite deposition, episodic drops in lake level resulted in erosion of shallow-water deposits, which were redeposited into the deeper lake. These sediment-focusing episodes are recognized by mixing of different mineralogies and crystal habits and mixing of a range of diatom fauna into poorly sorted mud layers. Lake-level drops are also indicated by erosional gaps in the shallow-water records and the occurrence of shoreline deposits in areas now covered by as much as 30 m of water. Calcite precipitation occurred for a short interval of time during the Holocene in response to an influx of Bear River water ca. 8 ka. The Pleistocene sedimentary record of Bear Lake until ca. 18 ka is dominated by siliciclastic glacial fl our derived from glaciers in the Uinta Mountains. The Bear Lake deep-water siliciclastic deposits are thoroughly bioturbated, whereas shallow-water deposits transitional to deltas in the northern part of the basin are upward-coarsening sequences of laminated mud, silt, and sand. A major drop in lake level occurred ca. 18 ka, resulting in subaerial exposure of the lake floor in areas now covered by

Major and trace element geochemistry of Lake Bogoria and Lake Nakuru, Kenya, during extreme draught.

PubMed

Jirsa, Franz; Gruber, Martin; Stojanovic, Anja; Omondi, Steve Odour; Mader, Dieter; Körner, Wilfried; Schagerl, Michael

2013-10-01

The physico-chemical properties of water samples from the two athalassic endorheic lakes Bogoria and Nakuru in Kenya were analysed. Surface water samples were taken between July 2008 and October 2009 in weekly intervals from each lake. The following parameters were determined: pH, salinity, electric conductivity, dissolved organic carbon (DOC), the major cations (FAAS and ICP-OES) and the major anions (IC), as well as certain trace elements (ICP-OES). Samples of superficial sediments were taken in October 2009 and examined using Instrumental Neutron Activation Analysis (INAA) for their major and trace element content including rare earth elements (REE). Both lakes are highly alkaline with a dominance of Na > K > Si > Ca in cations and HCO 3  > CO 3  > Cl > F > SO 4 in anions. Both lakes also exhibited high concentrations of Mo, As and fluoride. Due to an extreme draught from March to October 2009, the water level of Lake Nakuru dropped significantly. This created drastic evapoconcentration, with the total salinity rising from about 20‰ up to 63‰. Most parameters (DOC, Na, K, Ca, F, Mo and As) increased with falling water levels. A clear change in the quality of DOC was observed, followed by an almost complete depletion of dissolved Fe from the water phase. In Lake Bogoria the evapoconcentration effects were less pronounced (total salinity changed from about 40‰ to 48‰). The distributions of REE in the superficial sediments of Lake Nakuru and Lake Bogoria are presented here for the first time. The results show a high abundance of the REE and a very distinct Eu depletion of Eu/Eu* = 0.33-0.45.

Major and trace element geochemistry of Lake Bogoria and Lake Nakuru, Kenya, during extreme draught

PubMed Central

Jirsa, Franz; Gruber, Martin; Stojanovic, Anja; Omondi, Steve Odour; Mader, Dieter; Körner, Wilfried; Schagerl, Michael

2013-01-01

The physico-chemical properties of water samples from the two athalassic endorheic lakes Bogoria and Nakuru in Kenya were analysed. Surface water samples were taken between July 2008 and October 2009 in weekly intervals from each lake. The following parameters were determined: pH, salinity, electric conductivity, dissolved organic carbon (DOC), the major cations (FAAS and ICP-OES) and the major anions (IC), as well as certain trace elements (ICP-OES). Samples of superficial sediments were taken in October 2009 and examined using Instrumental Neutron Activation Analysis (INAA) for their major and trace element content including rare earth elements (REE). Both lakes are highly alkaline with a dominance of Na > K > Si > Ca in cations and HCO3 > CO3 > Cl > F > SO4 in anions. Both lakes also exhibited high concentrations of Mo, As and fluoride. Due to an extreme draught from March to October 2009, the water level of Lake Nakuru dropped significantly. This created drastic evapoconcentration, with the total salinity rising from about 20‰ up to 63‰. Most parameters (DOC, Na, K, Ca, F, Mo and As) increased with falling water levels. A clear change in the quality of DOC was observed, followed by an almost complete depletion of dissolved Fe from the water phase. In Lake Bogoria the evapoconcentration effects were less pronounced (total salinity changed from about 40‰ to 48‰). The distributions of REE in the superficial sediments of Lake Nakuru and Lake Bogoria are presented here for the first time. The results show a high abundance of the REE and a very distinct Eu depletion of Eu/Eu* = 0.33–0.45. PMID:25843965

2010 Second Refrigerator Recycling Program NV Energy - Southern Nevada: Program Year 2010

EPA Pesticide Factsheets

This measurement and verification report provides measured and verified energy impacts achieved by the Second Refrigerator Recycling Program that NV Energy offered to its customers in southern Nevada during 2010.

Sediment deposition and sources into a Mississippi River floodplain lake; Catahoula Lake, Louisiana

USGS Publications Warehouse

Latuso, Karen D.; Keim, Richard F.; King, Sammy L.; Weindorf, David C.; DeLaune, Ronald D.

2017-01-01

Floodplain lakes are important wetlands on many lowland floodplains of the world but depressional floodplain lakes are rare in the Mississippi River Alluvial Valley. One of the largest is Catahoula Lake, which has existed with seasonally fluctuating water levels for several thousand years but is now in an increasingly hydrologically altered floodplain. Woody vegetation has been encroaching into the lake bed and the rate of this expansion has increased since major human hydrologic modifications, such as channelization, levee construction, and dredging for improvement of navigation, but it remains unknown what role those modifications may have played in altering lake sedimentation processes. Profiles of thirteen 137Cs sediment cores indicate sedimentation has been about 0.26 cm y− 1 over the past 60 years and has been near this rate since land use changes began about 200 years ago (210Pb, and 14C in Tedford, 2009). Carbon sequestration was low (10.4 g m− 2 y− 1), likely because annual drying promotes mineralization and export. Elemental composition (high Zr and Ti and low Ca and K) and low pH of recent (<~60 y) or surface sediments suggest Gulf Coastal Plain origin, but below the recent sediment deposits, 51% of sediment profiles showed influence of Mississippi River alluvium, rich in base cations such as K+, Ca2 +, and Mg2 +. The recent shift to dominance of Coastal Plain sediments on the lake-bed surface suggests hydrologic modification has disconnected the lake from sediment-bearing flows from the Mississippi River. Compared to its condition prior to hydrologic alterations that intensified in the 1930s, Catahoula Lake is about 15 cm shallower and surficial sediments are more acidic. Although these results are not sufficient to attribute ecological changes directly to sedimentological changes, it is likely the altered sedimentary and hydrologic environment is contributing to the increased dominance of woody vegetation.

Distinguishing wild vs. stocked lake trout (Salvelinus namaycush) in Lake Ontario: Evidence from carbon and oxygen stable isotope values of otoliths

USGS Publications Warehouse

Schaner, T.; Patterson, W.P.; Lantry, B.F.; O'Gorman, R.

2007-01-01

We investigated the potential for using carbon and oxygen isotope values of otolith carbonate as a method to distinguish naturally produced (wild) lake trout (Salvelinus namaycush) from hatchery-reared lake trout in Lake Ontario. We determined δ 13C(CaCO3) and δ 18O(CaCO3) values of otoliths from juvenile fish taken from two hatcheries, and of otoliths from wild yearlings. Clear differences in isotope values were observed between the three groups. Subsequently we examined otoliths from large marked and unmarked fish captured in the lake, determining isotope values for regions of the otolith corresponding to the first year of life. Marked (i.e., stocked) fish showed isotope ratios similar to one of the hatchery groups, whereas unmarked fish, (wild fish or stocked fish that lost the mark) showed isotope ratios similar either to one of the hatchery groups or to the wild group. We interpret these data to suggest that carbon and oxygen isotope values can be used to determine the origin of lake trout in Lake Ontario, if a catalogue of characteristic isotope values from all candidate years and hatcheries is compiled.

The calcium isotope evolution of Lake Lisan, the Dead Sea glacial precursor

NASA Astrophysics Data System (ADS)

Bradbury, H. J.; Turchyn, A. V.; Wong, K.; Torfstein, A.

2016-12-01

Calcium is a stoichiometric component of carbonate minerals whose calcium isotopic composition reflects changes in the calcium isotope composition of the water from which it precipitates as well as the calcium isotope fractionation factor during precipitation. The lacustrine deposits of the last glacial Dead Sea (Lisan Formation) are dominated by carbonate minerals (aragonite) that record the geochemical history of the lake. The sediment sequence comprises alternating laminae of aragonite and clay-rich marls, interspersed with primary gypsum beds and disseminated secondary gypsum crystals. The aragonite precipitated annually during high lake stands associated with wet periods, while the primary gypsum precipitated during low lake conditions (arid periods). We report the calcium isotopic composition (δ44Ca in ‰ relative to bulk silicate earth) of primary aragonite laminae, primary gypsum and secondary gypsum at 1-5kyr resolution throughout the Lisan Formation sampled at the Masada section (70 - 14.5 ka). The δ44Ca of the primary gypsum averages +0.29‰, and displays smaller temporal variations than the aragonite, which averages -0.35‰ but ranges between +0.18‰ and -0.68‰. The aragonite δ44Ca changes temporally in sync with the previously reconstructed lake level suggesting the aragonite δ44Ca reflects changes in the lake calcium balance during lake level changes. The secondary gypsum composition (-0.3‰) corresponds to coeval aragonite samples. For the secondary gypsum to have a similar δ44Ca to the aragonite it is likely that the calcium derived from the aragonite in a near quantitative fashion through recrystallization of the aragonite to gypsum. A numerical box model is used to explore the effect of changing lake water levels on the calcium isotope composition of the aragonite and gypsum over the time interval studied.

Plasticity in the Oxidative Folding Pathway of the High Affinity Nerita Versicolor Carboxypeptidase Inhibitor (NvCI).

PubMed

Esperante, Sebastián A; Covaleda, Giovanni; Trejo, Sebastián A; Bronsoms, Sílvia; Aviles, Francesc X; Ventura, Salvador

2017-07-14

Nerita Versicolor carboxypeptidase inhibitor (NvCI) is the strongest inhibitor reported so far for the M14A subfamily of carboxypeptidases. It comprises 53 residues and a protein fold composed of a two-stranded antiparallel β sheet connected by three loops and stabilized by three disulfide bridges. Here we report the oxidative folding and reductive unfolding pathways of NvCI. Much debate has gone on whether protein conformational folding guides disulfide bond formation or instead they are disulfide bonds that favour the arrangement of local or global structural elements. We show here that for NvCI both possibilities apply. Under physiological conditions, this protein folds trough a funnelled pathway involving a network of kinetically connected native-like intermediates, all sharing the disulfide bond connecting the two β-strands. In contrast, under denaturing conditions, the folding of NvCI is under thermodynamic control and follows a "trial and error" mechanism, in which an initial quasi-stochastic population of intermediates rearrange their disulfide bonds to attain the stable native topology. Despite their striking mechanistic differences, the efficiency of both folding routes is similar. The present study illustrates thus a surprising plasticity in the folding of this extremely stable small disulfide-rich inhibitor and provides the basis for its redesign for biomedical applications.

FAA Air Traffic Activity: Fiscal Year 1988

DTIC Science & Technology

1988-01-01

12390 5335 TOTAL OPERATIONS ......................................................................... 146585 31593 9014 97579 8399 TEXARKANA (TXK) N...14402 12385 2017 TOTAL OPERATIONS ....................................................................... 56240 403 9574 41417 4846...WV N 390 39876 TEXARKANA ........................................................ AR N 351 56414 SOUTH LAKE TAHOE

The dynamics of the optically driven Lambda transition of the 15N-V- center in diamond.

PubMed

González, Gabriel; Leuenberger, Michael N

2010-07-09

Recent experimental results demonstrate the possibility of writing quantum information in the ground state triplet of the (15)N-V(-) center in diamond by means of an optically driven spin non-conserving two-photon Lambda transition in the presence of a strong applied electric field. Our calculations show that the hyperfine interaction in the (15)N-V(-) center is capable of mediating such a transition. We use a density matrix approach to describe the exact dynamics for the allowed optical spin non-conserving transitions between two sublevels of the ground state triplet. This approach allows us to calculate the Rabi oscillations, by means of which we obtain a Rabi frequency with an upper bound determined by the hyperfine interaction. This result is crucial for the success of implementing optically driven quantum information processing with the N-V center in diamond.

77 FR 68067 - Establishment of Class E Airspace; Coaldale, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-15

...-0705; Airspace Docket No. 12-AWP-4] Establishment of Class E Airspace; Coaldale, NV AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action establishes Class E airspace... forth in the NPRM for lowering the Class E airspace down to 1,200 feet above the surface was vague and...

Summit Lake landslide and geomorphic history of Summit Lake basin, northwestern Nevada

USGS Publications Warehouse

Curry, B. Brandon; Melhorn, W.N.

1990-01-01

The Summit Lake landslide, northwestern Nevada, composed of Early Miocene pyroclastic debris, Ashdown Tuff, and basalt and rhyolite of the Black Rock Range, blocked the upper Soldier Creek-Snow Creek drainage and impounded Summit Lake sometimes prior to 7840 yr B.P. The slide covers 8.2 km2 and has geomorphic features characteristic of long run-out landslides, such as lobate form, longitudinal and transverse ridges, low surface gradient (7.1 ??), and preservation of original stratigraphic position of transported blocks. However, estimated debris volume is the smallest reported (2.5 ?? 105 m3) for a landslide of this type. The outflow channel of the Summit Lake basin was a northward-flowing stream valley entrenched by Mahogany Creek. Subsequent negative tectonic adjustment of the basin by about 35 m, accompanied by concommitant progradation of a prominent alluvial fan deposited by Mahogany Creek, argues for a probable diversion of drainage from the Alvord basin southward into the Lahontan basin. The landslide occurred while the creek flowed southward, transferring about 147 km2 of watershed from the Lahontan basin back to the Alvord basin. Overflow northward occurred during high stands of Pluvial Lake Parman in the basin; otherwise, under drier climates, the Summit Lake basin has been closed. Within large depressions on the slide surface, the ca. 6800 yr old Mazama Bed and other sediments have buried a weakly developed soil. Disseminated humus in the soil yields an age of 7840 ?? 310 yr B.P. Absence of older tephra (such as St. Helens M) brackets the slide age between 7840 and 19,000 yr B.P. Projectile points found on the highest strandlines of Pluvial Lake Parman suggest a ca 8700 yr B.P. age by correlation with cultural artifacts and radiocarbon ages from nearby Last Supper Cave, Nevada. Organic matter accumulation in landslide soils suggests ages ranging from 9100 to 16,250 yr B.P. Estimation of the age of the slide from morphologic data for the isolated Summit

A Revised Holocene History of Lake Kivu, East Africa

NASA Astrophysics Data System (ADS)

Votava, J. E.; Johnson, T. C.; Hecky, R. E.

2013-12-01

The great lakes of the East African Rift valley are a vast chain of lakes formed in a region of active tectonics. These large, deep lakes are relatively old and many (e.g. Tanganyika, Malawi, and Turkana) have greatly influenced our understanding of terrestrial, tropical East African paleoclimate. Lake Kivu (max depth, 485m) sits at the heart of these rift lakes, north of Lake Tanganyika between the Democratic Republic of the Congo and Rwanda (roughly 250 km west of Lake Victoria). At over 1,400 meters in elevation, this 2,060 km2 mesotrophic lake has a complex stratification regime imposed by hydrothermal springs and deep waters supersaturated at STP in CO2 and CH4 gasses. The active Virunga Volcanoes to the north of the lake supply heated, high-salinity waters below 280 meters water depth maintaining the modern crenogenic meromixis. Based on detailed studies of diatom assemblages and bulk sedimentology, previous workers have suggested this hydrothermal activity began roughly 5,000 years BP. Unfortunately, dating and stratigraphic correlations of these original cores from the 1970 Woods Hole Oceanographic Institution's expedition have been problematic. Here we offer an improved chronology and new carbonate analyses from cores recovered in 2012 and 2013. Our AMS radiocarbon ages come from six terrigeneous macrofossils spanning the last 9,100 years (cal BP). These ages suggest a rather high sedimentation rate on the order of 70cm/kyr, and hence, our 8 m-long core provides us with a high-resolution lake history for the past 10,000 years. Most notable over the past 5,000 years in the lake history is the repeated onset and cessation of carbonate deposition, punctuated by organic-rich intervals. Earlier studies of the Woods Hole cores placed the onset of carbonate deposition at ca. 11,000 years BP suggesting changes in lake hydrology (i.e. closed to open), while the abrupt cessation of carbonate was dated at ca. 5,000 years BP and attributed to the beginning of

AV Reviews.

ERIC Educational Resources Information Center

Hays, Rachel, Ed.

1989-01-01

Presents teacher comments on audiovisual materials dealing with: biotechnology applications in immunology, agriculture, and cancer research; efforts to halt the eutrophication of Lake Tahoe; and banana slugs. Availability and costs of materials are included. (RT)

Highly photostable NV centre ensembles in CVD diamond produced by using N2O as the doping gas

NASA Astrophysics Data System (ADS)

Tallaire, A.; Mayer, L.; Brinza, O.; Pinault-Thaury, M. A.; Debuisschert, T.; Achard, J.

2017-10-01

High density Nitrogen-Vacancy (NV) centre ensembles incorporated in plasma assisted chemical vapour deposition (CVD) diamond are crucial to the development of more efficient sensing devices that use the properties of luminescent defects. Achieving high NV doping with N2 as the dopant gas source during diamond growth is, however, plagued by the formation of macroscopic and point defects that quench luminescence. Moreover, such NVs are found to exhibit poor photostability under high laser powers. Although this effect can be harnessed to locally and durably switch off NV luminescence for data storage, it is usually undesirable for most applications. In this work, the use of N2O as an alternative doping source is proposed. Much higher amounts of the doping gas can be added without significantly generating defects, which allows the incorporation of perfectly photostable and higher density NV ensembles. This effect is believed to be related to the lower dissociation energy of the N2O molecule together with the beneficial effect of the presence of a low and controlled amount of oxygen near the growing surface.

78 FR 68699 - Establishment of Class E Airspace; Battle Mountain, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-15

...) navigation aid, Battle Mountain, NV. A favorable comment from the National Business Aviation Association...-4537. SUPPLEMENTARY INFORMATION: History The FAA published a final rule in the Federal Register... Final Rule Accordingly, pursuant to the authority delegated to me, the description under the History...

Geochemical and Geophysical Analysis of Holocene-aged Sediments from Southeastern Tulare Lake, CA

NASA Astrophysics Data System (ADS)

Prosser, L.; Jackson, B.; Roza, J.

2015-12-01

Tulare Lake is located in the San Joaquin Valley of California west of the Sierra Nevada mountains (Preston, 1981). The Poso Canal trench locality is located in the southeastern portion of Tulare Lake in the Ton Tachi lake plane south of the Atwell Island sand spit. This area was chosen because these sediments lie beneath a road bed that predates agricultural tilling, preserving late-Holocene lake sediments. Sediments from trench TL13-7C were sampled for geophysical and geochemical analyses in order to create a higher resolution lake-level history during the late-Holocene than had been possible using only lithologic descriptions. The new record is comprised of grain size, clay percentage, carbon/nitrogen (C/N) ratios, total inorganic carbon (TIC), total organic carbon (TOC), and nitrogen (N) analyses taken at 2-cm intervals over 181-cm of section comprising four lithologic units. From oldest to youngest, Unit 1A consists of relatively equal and steady percentages of clay, silt, and sand, and relatively low C/N ratios, TIC, TOC, and N, suggesting an unproductive lake and relatively deep lake levels at this high elevation site. Fluctuating C/N ratios, a steady decrease in clay percentage, and a steady increase in sand percentage in Unit 1B suggests periods of flooding and fluctuating lake levels and eventually shallow evaporative lake conditions, as evidenced by a considerable and sudden increase in TIC (to 4.51%) in Unit 2. In addition to the drastic change in TIC, Unit 2 shows evidence of a large influx of terrestrial organic matter perhaps transported by floods by an increase in sand percentage and two pronounced spikes in C/N ratios to 38 and 65 (Meyers and Lallier-Verges, 1999). Unit 3 shows low but steady levels of clay and sand percentages, and higher but steady levels of silt. Levels of TIC, TOC, C/N, and N are all steady, with relatively higher levels of TOC and N, which are indicators of high lake level and productivity (Cohen, 2003). Unit 4 is very similar

Groundwater Quality Data for the Tahoe-Martis Study Unit, 2007: Results from the California GAMA Program

USGS Publications Warehouse

Fram, Miranda S.; Munday, Cathy; Belitz, Kenneth

2009-01-01

Groundwater quality in the approximately 460-square-mile Tahoe-Martis study unit was investigated in June through September 2007 as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The study was designed to provide a spatially unbiased assessment of the quality of raw groundwater used for public water supplies within the Tahoe-Martis study unit (Tahoe-Martis) and to facilitate statistically consistent comparisons of groundwater quality throughout California. Samples were collected from 52 wells in El Dorado, Placer, and Nevada Counties. Forty-one of the wells were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study area (grid wells), and 11 were selected to aid in evaluation of specific water-quality issues (understanding wells). The groundwater samples were analyzed for a large number of synthetic organic constituents (volatile organic compounds [VOC], pesticides and pesticide degradates, and pharmaceutical compounds), constituents of special interest (perchlorate and N-nitrosodimethylamine [NDMA]), naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), radioactive constituents, and microbial indicators. Naturally occurring isotopes (tritium, carbon-14, strontium isotope ratio, and stable isotopes of hydrogen and oxygen of water), and dissolved noble gases also were measured to help identify the sources and ages of the sampled groundwater. In total, 240 constituents and water-quality indicators were investigated. Three types of quality-control samples (blanks, replicates, and samples for matrix spikes) each were collected at 12 percent of the wells, and the

Biomagnetic Imaging Applications using NV Centers in Diamond

NASA Astrophysics Data System (ADS)

Glenn, David; Lesage, David; Connolly, Colin; Walsworth, Ronald

2015-05-01

We present new measurements of magnetic fields produced by a range of biological specimens using a wide-field magnetic imaging system based on NV centers in diamond. In particular, we show (i) the first magnetic images of a previously unstudied strain of magnetotactic bacteria, and (ii) a general platform for magnetic imaging of immunomagnetically labeled cells, which provides a useful alternative to traditional immunofluorescence techniques in the presence of strong autofluorescence and/or optically scattering media.

Lake Qinghai sediment geochemistry linked to hydroclimate variability since the last glacial

NASA Astrophysics Data System (ADS)

Jin, Zhangdong; An, Zhisheng; Yu, Jimin; Li, Fuchun; Zhang, Fei

2015-08-01

Geochemistry of basin sediments from semi-arid regions is valuable to understand past hydroclimatic changes. Here, we investigate the links of sedimentary geochemistry (Rb, Sr, Ca/Zr, TOC, and %CaCO3), carbonate mineralogy and ostracod shell δ18O of Lake Qinghai, a basin proximal to major dust production centers at mid-latitudes of the Northern Hemisphere, to changes in depositional conditions and hydroclimate during the past 32 ka. Surface lacustrine sediments are characterized by low-Rb, high-Sr, low-Rb/Sr, high-%CaCO3 and high-Ca/Zr values, in contrast to the chemical compositions of eolian loess (high-Rb, low-Sr, high-Rb/Sr, low-%CaCO3, and low-Ca/Zr). A direct comparison of soluble Ca and Sr in two short cores with instrumental water discharge data suggests that lacustrine precipitates in Lake Qinghai are dominated by authigenic aragonite formed under Ca2+-limited water conditions, and that the accumulation rate of aragonite dominantly depends on solute fluxes into the lake during the rainy seasons (late May to September). Our high-resolution down-core records show that sediments during the last glacial (∼32-19.8 ka) had high-Rb, low-Sr, low-%CaCO3, and low-Ca/Zr, indicating eolian dust (loess) accumulation in a desiccated basin under dry glacial conditions, further supported by grain size and pollen results. This type of sedimentation was maintained during the last deglacial (∼19.8-11.5 ka), but interrupted by episodic lacustrine precipitates with high-Sr, high-%CaCO3, high-Ca/Zr, and low-Rb. At ∼11.5 ka, sedimentary Rb/Sr, Ca/Zr, %CaCO3 and TOC show dramatic and permanent changes, implying an abrupt shift in the atmospheric circulation at the onset of the Holocene in the Lake Qinghai region. Lacustrine precipitates have persisted throughout the Holocene with a maximum during the early to mid-Holocene (∼10.5-8.0 ka). Since ∼8.0 ka, the gradual and significant decreases in aragonite and Sr accumulations in tandem with increasing dust deposit and

75 FR 12975 - Establishment of Class E Airspace; Battle Mountain, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-18

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 [Docket No. FAA-2009-1057; Airspace Docket No. 09-AWP-9] Establishment of Class E Airspace; Battle Mountain, NV AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action will establish Class...

Dispersive estimates for rational symbols and local well-posedness of the nonzero energy NV equation. II

NASA Astrophysics Data System (ADS)

Kazeykina, Anna; Muñoz, Claudio

2018-04-01

We continue our study on the Cauchy problem for the two-dimensional Novikov-Veselov (NV) equation, integrable via the inverse scattering transform for the two dimensional Schrödinger operator at a fixed energy parameter. This work is concerned with the more involved case of a positive energy parameter. For the solution of the linearized equation we derive smoothing and Strichartz estimates by combining new estimates for two different frequency regimes, extending our previous results for the negative energy case [18]. The low frequency regime, which our previous result was not able to treat, is studied in detail. At non-low frequencies we also derive improved smoothing estimates with gain of almost one derivative. Then we combine the linear estimates with a Fourier decomposition method and Xs,b spaces to obtain local well-posedness of NV at positive energy in Hs, s > 1/2. Our result implies, in particular, that at least for s > 1/2, NV does not change its behavior from semilinear to quasilinear as energy changes sign, in contrast to the closely related Kadomtsev-Petviashvili equations. As a complement to our LWP results, we also provide some new explicit solutions of NV at zero energy, generalizations of the lumps solutions, which exhibit new and nonstandard long time behavior. In particular, these solutions blow up in infinite time in L2.

Lake size and water-column stability affect the importance of methane for pelagic food webs of boreal lakes

NASA Astrophysics Data System (ADS)

Kankaala, Paula; Lopez-Bellido, Jessica; Ojala, Anne; Tulonen, Tiina; Jones, Roger I.

2013-04-01

Physical forcing, related to lake size and morphometry, plays an important role in the landscape-scale biogeochemical processing and fluxes of terrestrial carbon in lakes. Boreal lakes are typically dimictic, with mixing of the water column in spring and autumn, but in small, sheltered, humic, forest lakes the spring mixing is often incomplete. This leads to a steep summer stratification and oxygen depletion in the hypolimnion of the lakes. As a result of anaerobic decomposition of organic matter, high concentrations of CH4are typical in these lakes. At the oxic-anoxic interface zone methanotrophic microbes oxidize CH4 to CO2 and partly incorporate CH4-C into microbial biomass, and thus potentially provide a diet source for pelagic consumers. We studied production at the base of the pelagic food web by methane oxidising bacteria (MOB), heterotrophic bacteria (HB) and phytoplankton (PP) in five boreal lakes with a dissolved organic carbon (DOC) concentration varying between 7 and 25 mg C L-1 and an area ranging from 0.004 to 13.4 km2. High MOB activity was detected in the water columns of the three smallest lakes having anoxia in the hypolimnion during summer. The highest MOB activities (ca. 2-12 μmol L-1 d-1) were observed when the CH4:O2 ratio varied between ca. 0.5-12. Seasonally, the highest MOB activities were measured during late-summer mixed layer deepening and autumnal mixing of the whole water column. The proportion of MOB in the total basal production was highest in the two smallest lakes (24-56 and 13-36%), having the steepest summertime stratification. The proportion MOB in the basal production decreased with lake size being 70% of basal production was by PP. In all studied lakes HB contributed only 10-23% of the total basal production, suggesting that a transfer of allochthonous DOC via HB plays only a modest role for the nutrition of the higher trophic levels.

Late-glacial and early Holocene changes in vegetation and lake-level at Hauterive/Rouges-Terres, Lake Neuchâtel (Switzerland)

NASA Astrophysics Data System (ADS)

Magny, Michel; Thew, Nigel; Hadorn, Philippe

2003-01-01

Palynological and sedimentological analyses of a sedimentary sequence sampled at Hauterive/Rouges-Terres, Lake Neuchâtel (Switzerland) provide documentation of changes in vegetation and lake-level during the Bølling, Younger Dryas and Preboreal pollen zones, and have allowed a comparison with sequences covering the same period from other sites located in the western part of the Swiss Plateau. The Juniperus-Hippophaë zone (regional pollen assemblage zone (RPAZ) CHb-2, first part of the Bølling, ca. 14 650-14 450 cal. yr BP) was characterised by a generally low lake-level. A weak rise occurred during this zone. The Juniperus-Hippophaë to Betula zone transition coincided with a lake-level lowering, interrupted by a short-lived but marked phase of higher lake-level recorded at the neighbouring site of Hauterive-Champréveyres, but not present at Hauterive/Rouges-Terres owing to an erosion surface. Shortly after the beginning of the Betula zone (RPAZ CHb-3, second part of the Bølling, ca 14 450-14 000 cal. yr BP), a marked rise in lake-level occurred. It was composed of two successive periods of higher level, coinciding with high values of Betula, separated by a short episode of relatively lower lake-level associated with raised values in Artemisia and other non-arboreal pollen. The last part of RPAZ CHb-3 saw a fall in lake-level. The lower lake-levels during RPAZ CHb-2 to early RPAZ CHb-3 can be correlated with the abrupt warming at the beginning of the Greenland Interstadial (GI) 1e thermal maximum. The successive episodes of higher lake-level punctuating the GI 1e might be linked to the so-called Intra-Bølling Cold Oscillations identified from several palaeoclimatic records in the North Atlantic area, and also documented in oxygen-isotope data sets from Swiss Plateau lakes. The Hauterive/Rouges-Terres lake-level record provides evidence for marked climatic drying through the second part of the Younger Dryas event (GS1), during the GS1-Preboreal (RPAZ CHb-4b-4

18. Photocopy of a photographca. 1950showing Lake Hodges Dam in ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

18. Photocopy of a photograph--ca. 1950--showing Lake Hodges Dam in San Diego County, CA., during a period of low water. Courtesy Mr. Charles Allan Whitney. - Little Rock Creek Dam, Little Rock Creek, Littlerock, Los Angeles County, CA

75 FR 17896 - Sierra County, CA, Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-08

... issues relating to implementing the Secure Rural Schools and Community Self-Determination Act of 2000... National Forest System lands on the Humboldt- Toiyabe, Plumas and Tahoe National Forests in Sierra County...

75 FR 22100 - Sierra County, CA, Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-27

... issues relating to implementing the Secure Rural Schools and Community Self Determination Act of 2000... National Forest System lands on the Humboldt-Toiyabe, Plumas and Tahoe National Forests in Sierra County...

Traveltime for the Truckee River between Tahoe City, California, and Vista, Nevada, 2006 and 2007

USGS Publications Warehouse

Crompton, E. James

2008-01-01

Traveltime measurements were made during 2006 and 2007 along the Truckee River between Tahoe City, Calif., and Vista, Nev. Fluorescent rhodamine WT dye was injected at various locations along the river during streamflows ranging from 143 to 2,660 cubic feet per second. The resulting data, presented in tabular and graphic form, may be useful to water-quality modelers or water-resources managers concerned with predicting the movement of soluble contaminants accidentally spilled into the Truckee River. The data provided in this report also could be used to determine the dispersion-related characteristics (duration and magnitude of pollutant concentrations) that may be expected in the Truckee River.

Glacial lakes in the Indian Himalayas--from an area-wide glacial lake inventory to on-site and modeling based risk assessment of critical glacial lakes.

PubMed

Worni, Raphael; Huggel, Christian; Stoffel, Markus

2013-12-01

Glacial lake hazards and glacial lake distributions are investigated in many glaciated regions of the world, but comparably little attention has been given to these topics in the Indian Himalayas. In this study we present a first area-wide glacial lake inventory, including a qualitative classification at 251 glacial lakes >0.01 km(2). Lakes were detected in the five states spanning the Indian Himalayas, and lake distribution pattern and lake characteristics were found to differ significantly between regions. Three glacial lakes, from different geographic and climatic regions within the Indian Himalayas were then selected for a detailed risk assessment. Lake outburst probability, potential outburst magnitudes and associated damage were evaluated on the basis of high-resolution satellite imagery, field assessments and through the use of a dynamic model. The glacial lakes analyzed in the states of Jammu and Kashmir and Himachal Pradesh were found to present moderate risks to downstream villages, whereas the lake in Sikkim severely threatens downstream locations. At the study site in Sikkim, a dam breach could trigger drainage of ca. 16×10(6)m(3) water and generate maximum lake discharge of nearly 7000 m(3) s(-). The identification of critical glacial lakes in the Indian Himalayas and the detailed risk assessments at three specific sites allow prioritizing further investigations and help in the definition of risk reduction actions. Copyright © 2012 Elsevier B.V. All rights reserved.

Landscape influences on climate-related lake shrinkage at high latitudes

USGS Publications Warehouse

Roach, Jennifer K.; Griffith, Brad; Verbyla, David

2013-01-01

Climate-related declines in lake area have been identified across circumpolar regions and have been characterized by substantial spatial heterogeneity. An improved understanding of the mechanisms underlying lake area trends is necessary to predict where change is most likely to occur and to identify implications for high latitude reservoirs of carbon. Here, using a population of ca. 2300 lakes with statistically significant increasing and decreasing lake area trends spanning longitudinal and latitudinal gradients of ca. 1000 km in Alaska, we present evidence for a mechanism of lake area decline that involves the loss of surface water to groundwater systems. We show that lakes with significant declines in lake area were more likely to be located: (1) in burned areas; (2) on coarser, well-drained soils; and (3) farther from rivers compared to lakes that were increasing. These results indicate that postfire processes such as permafrost degradation, which also results from a warming climate, may promote lake drainage, particularly in coarse-textured soils and farther from rivers where overland flooding is less likely and downslope flow paths and negative hydraulic gradients between surface water and groundwater systems are more common. Movement of surface water to groundwater systems may lead to a deepening of subsurface flow paths and longer hydraulic residence time which has been linked to increased soil respiration and CO2 release to the atmosphere. By quantifying relationships between statewide coarse resolution maps of landscape characteristics and spatially heterogeneous responses of lakes to environmental change, we provide a means to identify at-risk lakes and landscapes and plan for a changing climate.

Rangewide glaciation in the Sierra Nevada, California

USGS Publications Warehouse

Moore, James G.; Moring, Barry C.

2013-01-01

The 600-km-long Sierra Nevada underwent extensive Pleistocene glaciation except for its southernmost 100 km. Presently, ∼1700 small glaciers and ice masses near the crest of the range occur above 3250 m in elevation; these covered an area of ∼50 km2 in 1972. Fourteen of the largest glaciers decreased by about one half in area during the period from 1900 to 2004.Rock glaciers, generally glacial ice covered by 1–10 m of rockfall debris, occur in about the same span of the range as ice and permanent snowfields. They are, on average, lower by 200–300 m, apparently because of the insulating layer of rocky rubble that protects their internal ice from the sun’s heat and from wind.The principal Pleistocene glacial stages are the Sherwin (ca. 820 ka), Tahoe (170–130 and ca. 70 ka), Tioga (14–28 ka), and Recess Peak (13 ka). Some 7040 glacial lakes, produced primarily by quarrying from bedrock, were mostly exposed after recession of the Tioga glacial stage. The lakes largely mark the area of primary snow accumulation. Below the lower limit of the lakes, ice flowed downward into river-cut canyons, forming major trunk glaciers within the zone of ablation.The range is in general a westward-tilted block upfaulted on its east side. Therefore, the main late Pleistocene trunk glaciers (Tahoe/Tioga) west of the crest extend 25–60 km, whereas those east of the crest extend only 5–20 km. Because of higher precipitation northward, glacial features such as the toes of existing glaciers and rock glaciers, as well as the late season present-day snowline, all decrease in elevation northward. Likewise, the elevation of the lower limit of glacial lakes, an indication of the zone of snow accumulation during the late Pleistocene, decreases about the same degree. This similarity suggests that the overall climate patterns of the late Pleistocene, though cooler, were similar to those of today. The east slope glaciers show a similar northward depression, but they are ∼500�

High Resolution Environmental Magnetic Study of a Holocene Sedimentary Record from Zaca Lake, Ca

NASA Astrophysics Data System (ADS)

Platzman, E. S.; Lund, S.; Kirby, M. E.; Feakins, S. J.

2012-12-01

Magnetic studies of Holocene lake sediments recovered from Zaca lake have yielded a 3000-year high resolution record of environmental variability and paleolimnology. Zaca lake is a small oligomictic lake ~12m deep situated 730 m above sea level in the steep canyons of the San Rafael mountains, NW of Santa Barbara. Throughout much of the year Zaca lake is anaerobic below 7m. Hydrogen sulfide, fed into the lake via runoff and local sulphur springs, is present throughout the hypolimnion with concentrations sometime exceeding 30 mg/ l. During the summer months when the lake is stratified, light colored carbonate rich microlaminae are formed; and often during the winter months when the lake overturns, killing the anaerobic bacteria, black microlamina rich in iron sulfide are deposited on the lake floor, creating a stratigraphy reflecting patterns of environmental variability on annual to millennial scales. Samples for magnetic analysis were obtained from 8.5 m of core recovered from the central region of Zaca lake. Ages, constrained using radiocarbon chronostratigraphy, yielded sedimentation rates of 2-10 mm/yr with an average rate of 3 mm per yr over the 3000 yr interval. Parameters reflecting decadal scale variability in magnetic concentration (susceptibility, ARM, SIRM) and grainsize (ARM/Chi) were measured every 2 cm. Additional rock magnetic tests, including thermal demagnetization of three component IRM, were applied at selected intervals to constrain the magnetic mineralogy. These data were combined with analyses of clastic grain size, % calcium carbonate and % organics to create a multiproxy record of environmental variability. Results show that Zaca lake has had a complex depositional history. Anthropogenic effects associated with European colonization are present in the upper meters. Most notable, however, is a dramatic shift in the magnetic parameters and mineralogy between the upper and lower half of the core (circa 1300 ybp) indicating a shift in regime

Habitat quality and recruitment success of cui-ui in the Truckee River downstream of Marble Bluff Dam, Pyramid Lake, Nevada

USGS Publications Warehouse

Scoppettone, G. Gary; Rissler, Peter H.; Salgado, J. Antonio; Harry, Beverly

2013-01-01

We compared cui-ui (Chasmistes cujus) recruitment from two reaches of the Truckee River with histories of severe erosional downcutting caused by a decline in Pyramid Lake surface elevation. In 1975, Marble Bluff Dam (MBD) was constructed 5 kilometers upstream of the extant mouth of the Truckee River to stabilize the upstream reach of the river; the downstream reach of the river remained unstable and consequently unsuitable for cui-ui recruitment. By the early 2000s, there was a decrease in the Truckee River’s slope from MBD to Pyramid Lake after a series of wet years in the 1990s. This was followed by changes in river morphology and erosion abatement. These changes led to the question as to cui-ui recruitment potential in the Truckee River downstream of MBD. In 2012, more than 7,000 cui-ui spawners were passed upstream of MBD, although an indeterminate number of cui-ui spawned downstream of MBD. In this study, we compared cui-ui recruitment upstream and downstream of MBD during a Truckee River low-flow year (2012). Cui-ui larvae emigration to Pyramid Lake began earlier and ended later downstream of MBD. A greater number of cui-ui larvae was produced downstream of MBD than upstream. This also was true for native Tahoe sucker (Catostomus tahoensis) and Lahontan redside (Richardsonius egregius). The improved Truckee River stability downstream of MBD and concomitant cui-ui recruitment success is attributed to a rise in Pyramid Lake's surface elevation. A decline in lake elevation may lead to a shift in stream morphology and substrate composition to the detriment of cui-ui reproductive success as well as the reproductive success of other native fishes.

75 FR 13297 - Southeastern Lincoln County Habitat Conservation Plan, Lincoln County, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-19

... development), flood control activities (within the City of Caliente), maintenance of Lincoln County roads and... library locations: (1) Clark County Library, 1401 E. Flamingo Road, Las Vegas, NV 89119; (702) 507-3400...- administered land. Proposed covered activities include: (1) Planned land development and maintenance activities...

78 FR 2646 - Proposed Modification of Class B Airspace; Las Vegas, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-14

..., NV AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed rulemaking (NPRM); Reopening of comment period. SUMMARY: This action reopens the comment period for an NPRM that was published... reasoned regulatory decisions on the proposal. Comments are specifically invited on the overall regulatory...

Changing abundance of Hexagenia mayfly nymphs in western Lake Erie of the Laurentian Great Lakes: Impediments to assessment of lake recovery?

USGS Publications Warehouse

Schloesser, D.W.; Nalepa, T.F.

2001-01-01

After an absence of 40 years, mayfly nymphs of the genus Hexagenia were found in sediments of western Lake Erie of the Laurentian Great Lakes in 1993 and, by 1997, were abundant enough to meet a mayfly-density management goal (ca. 350 nymphs m—2) based on pollution-abatement programs. We sampled nymphs in western Lake Erie and Lake St. Clair, located upstream of western Lake Erie, to determine the importance of seasonal abundance and life-history characteristics of nymphs (e.g., emergence and recruitment) on density estimates relative to the mayfly-density management goal. Two types of density patterns were observed: (1) densities were relatively high in spring and gradually decreased through late summer (observed in Lake Erie and Lake St. Clair in 1997 and Lake St. Clair in 1999) and (2) densities were relatively high in spring, gradually decreased to mid summer, abruptly decreased in mid summer, and then increased between summer and late fall (Lake Erie and Lake St. Clair in 1998 and Lake Erie in 1999). Length-frequency distributions of nymphs and observations of adults indicate that the primary cause for the two density patterns was attributed to failed (first pattern) and successful (second pattern) reproduction and emergence of nymphs into adults in mid summer. Gradual declines in densities were attributed to mortality of nymphs. Our results indicate that caution should be used when evaluating progress of pollution-abatement programs based on mayfly densities because recruitment success is variable both between and within years. Additionally, the interpretation of progress toward management goals, relative to the restoration of Hexagenia populations in the Great Lakes and possibly other water bodies throughout the world, is influenced by the number of years in which consequtive collections are made.

78 FR 7773 - Cargill Power Markets, LLC v. NV Energy, Inc., Notice of Complaint

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-04

...), Cargill Power Markets, LLC (Complainant or CPM) filed a formal complaint against NV Energy, Inc... processed CPM's Transmission Service Request, as more fully described in the complaint. The Complainant...

RECENT GEOCHEMICAL SAMPLING AND MERCURY SOURCES AT SULPHUR BANK MERCURY MINE, LAKE COUNTY, CA

EPA Science Inventory

The Sulphur Bank Mercury Mine (SBMM), located on the shore of Clear Lake in Lake County, California, has been identified as a significant source of mercury to the lake. Sulphur Bank was actively minded from the 1880's to the 1950's. Mining and processing operations at the Sulph...

First evidence of grass carp recruitment in the Great Lakes Basin

USGS Publications Warehouse

Chapman, Duane C.; Davis, J. Jeremiah; Jenkins, Jill A.; Kocovsky, Patrick M.; Miner, Jeffrey G.; Farver, John; Jackson, P. Ryan

2013-01-01

We use aging techniques, ploidy analysis, and otolith microchemistry to assess whether four grass carp Ctenopharyngodon idella captured from the Sandusky River, Ohio were the result of natural reproduction within the Lake Erie Basin. All four fish were of age 1 +. Multiple lines of evidence indicate that these fish were not aquaculture-reared and that they were most likely the result of successful reproduction in the Sandusky River. First, at least two of the fish were diploid; diploid grass carp cannot legally be released in the Great Lakes Basin. Second, strontium:calcium (Sr:Ca) ratios were elevated in all four grass carp from the Sandusky River, with elevated Sr:Ca ratios throughout the otolith transect, compared to grass carp from Missouri and Arkansas ponds. This reflects the high Sr:Ca ratio of the Sandusky River, and indicates that these fish lived in a high-strontium environment throughout their entire lives. Third, Sandusky River fish were higher in Sr:Ca ratio variability than fish from ponds, reflecting the high but spatially and temporally variable strontium concentrations of southwestern Lake Erie tributaries, and not the stable environment of pond aquaculture. Fourth, Sr:Ca ratios in the grass carp from the Sandusky River were lower in their 2011 growth increment (a high water year) than the 2012 growth increment (a low water year), reflecting the observed inverse relationship between discharge and strontium concentration in these rivers. We conclude that these four grass carp captured from the Sandusky River are most likely the result of natural reproduction within the Lake Erie Basin.

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.

78 FR 21849 - Television Broadcasting Services; Ely, NV to Middletown Township, NJ

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-12

... FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 [MB Docket No. 13-72; RM-11694, DA 13-448] Television Broadcasting Services; Ely, NV to Middletown Township, NJ AGENCY: Federal Communications... to Middletown, New Jersey, pursuant to section 331(a) of the Communications Act of 1934, as amended...

Development of an information data base for watershed monitoring

NASA Technical Reports Server (NTRS)

Smith, A. Y.; Blackwell, R. J.

1980-01-01

Landsat multispectral scanner data, Defense Mapping Agency digital terrain data, conventional maps, and ground data were integrated to create a comprehensive information data base (the Image Based Information System), to monitor the water quality of the Lake Tahoe Basin. Landsat imagery was used as the planimetric base to which all other data were registered. A georeference image plane, which provided an interface between all data planes for the Lake Tahoe Basin data base, was created from the drainage basin map. The data base was used to extract each drainage basin for separate display. The Defense Mapping Agency-created elevation image was processed with VICAR software to produce a component representing slope magnitude, which was cross-tabulated with the drainage basin georeference table. Future applications of the data base include the development of precipitation modeling, surface runoff models, and classification of drainage basin cover types.

Anaerobic Oxidation of Methane in a French meromictic lake (Lake Pavin): Who is responsible?

NASA Astrophysics Data System (ADS)

Grossi, V.; Attard, E.; Birgel, D.; Schaeffer, P.; Jézéquel, D.; Lehours, A.

2012-12-01

Methane is an important greenhouse gas and its biogeochemical cycle is of primary significance to the global carbon cycle. The Anaerobic Oxidation of Methane (AOM) has been estimated to be responsible for >90% of methane consumption. This biogeochemical process has been increasingly documented during the last two decades but the underlying microbial processes and their key agents remain incompletely understood. Freshwater lakes account for 2-10% of the total emissions of methane and are therefore an important part of the global methane cycle. Lake Pavin is a French meromictic crater lake with unusual hydrological characteristics: its morphology (depth >92m, mean diameter 750m) induce that waters below 60m are never mixed with overlying waters and remain permanently anoxic. The deep anoxic waters of Lake Pavin contain high concentrations (i.e. 4 mM) of methane but, contrary to other aquatic systems, almost no methane escapes from the lake. Previous biogeochemical and modeling studies suggest that methane is preferentially consumed within the oxic-anoxic transition zone (ca. 55-60 m depth) but that ca. 30% of methane oxidation occurs in the anoxic part of the lake. Phylogenetic (16S rRNA) analyses showed that ANME generally involved in AOM (ANME-1, -2 and -3) are not present in Lake Pavin. Other archaeal groups that do not have any cultured representatives so far appear well represented in the anoxic parts of the lake but their implication in AOM is not demonstrated. The analysis of lipid biomarkers using GC-MS and LC-MS revealed the presence of a low diversity of archaeal-specific biomarkers in the superficial sediments and in the anoxic waters of the lake. Archaeol and caldarcheaol (GDGT-0) are the two main archaeal core lipids detected; other biomarkers generally present in ANME such as pentamethylicosane or hydroxyarchaeol are not present. However, the stable carbon isotopic composition of archaeol (δ13C = -18‰) and of the biphytane chain of GDGT-0 (δ13C

Biogeochemistry of a soil catena in the eastern Sierra Nevada Range, NV

USDA-ARS?s Scientific Manuscript database

As a field/lab project, students in the Soil Biogeochemistry class of the University of Nevada, Reno described and characterized five pedons at Little Valley, NV, at the eastern edge of the Sierra Nevada. Developed largely from granite, the catena encompassed five pedons, which from high to low elev...

Coherent manipulation of an NV center and one carbon nuclear spin

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

Scharfenberger, Burkhard; Nemoto, Kae; Munro, William J.

2014-12-04

We study a three-qubit system formed by the NV center’s electronic and nuclear spin plus an adjacent spin 1/2 carbon {sup 13}C. Specifically, we propose a manipulation scheme utilizing the hyperfine coupling of the effective S=1 degree of freedom of the vacancy electrons to the two adjacent nuclear spins to achieve accurate coherent control of all three qubits.

77 FR 15389 - Notice of Inventory Completion: California Department of Parks and Recreation, Sacramento, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-15

... associated funerary objects were removed from the Cole Creek site (CA-LAK-425), Lake County, CA. This notice... remains representing, at minimum, one individual were removed from the Cole Creek site (CA-LAK-425) in...

Value distribution assessment of geothermal development in Lake County, CA

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

Churchman, C.W.; Nelson, H.G.; Eacret, K.

1977-10-01

A value distribution assessment is defined as the determination of the distribution of benefits and costs of a proposed or actual development, with the intent of comparing such a development with alternative plans. Included are not only the social and economic effects, but also people's perceptions of their roles and how they are affected by the proposed or actual development. Discussion is presented under the following section headings: on morality and ethics; the vanishing community; case study of pre-development planning--Lake County; methodology for research; Lake County geothermal energy resource; decision making; Planning Commission hearing; communication examples; benefit tracing; response tomore » issues raised by the report of the State Geothermal Task Force; and, conclusions and recommendations. (JGB)« less

Phosphate and carbonate mass balances and their relationships to ground-water inputs at Beaver Lake, Waukesha County, Wisconsin. Technical report

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

Brown, B.E.; Cherkauer, D.S.

1991-01-01

The water and chemical budgets of Beaver Lake, Waukesha County, Wisconsin were examined to determine the role of groundwater and sediments in controlling lake quality in a seepage lake. Groundwater dominates the water budget, providing 70% of annual inflow and 60% of the outflow. The 15-m deep lake diverts flow from a depth of at least 90 m in the glacial aquifer of which it is a part. Acting as a flow-through system, the lake receives inflow predominantly from nearshore springs. Outflow occurs in the deeper parts of the lake. Groundwater provides more than 90% of the mass inflow ofmore » the major chemicals examined (Ca, Mg, Na, K, HCO3, SO4, Cl and NO3). It is also the major path of outflow for chemicals, accounting for more than 60% of the lake's loss of all the above ions except Ca and HCO3. Sedimentation of 270 + or - 82 g/sqm/yr of precominatly CaCO3 marl with significant silica and organic matter accounts for removal of 43 and 15% of the Ca and HCO3, respectively. Losses of Mg, Na, K, S and Cl to the sediment are insignificant. Data on NO3 fluxes indicate groundwater provides more N than can be accounted for in water and sediment effluxes. Seasonal denitrification in the lake's hypolimnion may account for the difference.« less

A Latest Glacial and Holocene Record From Medicine Lake, Siskiyou County, California: Preliminary Diatom, Pollen, and Sediment Data

NASA Astrophysics Data System (ADS)

Starratt, S. W.; Barron, J. A.; Kneeshaw, T.; Phillips, L.; Lowenstern, J.; Wanket, J. A.

2002-12-01

high lake levels, whereas pollen of aquatic taxa (primarily Isoetes [quillwort]) increases in significance at lower lake levels. Total organic carbon is higher during high stands and lower during low stands. Comparison with recently published multi-proxy studies of the Lake Tahoe-Truckee River-Pyramid Lake drainage system suggest that some of the changes in lake level observed at Medicine Lake between about 7,500-4,500 cal yr B.P. may be regional in nature, while fluctuations over the last 4,500 yr probably reflect conditions affecting only the local watershed.

Lake Tahoe Restoration Act of 2009

THOMAS, 111th Congress

Sen. Reid, Harry [D-NV

2009-11-03

Senate - 06/21/2010 Placed on Senate Legislative Calendar under General Orders. Calendar No. 436. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

Lake Tahoe Restoration Act of 2009

THOMAS, 111th Congress

Rep. Heller, Dean [R-NV-2

2009-11-03

House - 06/18/2010 Referred to the Subcommittee on Department Operations, Oversight, Nutrition and Forestry. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

Lake Tahoe Restoration Act of 2013

THOMAS, 113th Congress

Sen. Feinstein, Dianne [D-CA

2013-08-01

Senate - 06/05/2014 Placed on Senate Legislative Calendar under General Orders. Calendar No. 422. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

Lake Tahoe Restoration Act of 2011

THOMAS, 112th Congress

Sen. Feinstein, Dianne [D-CA

2011-03-02

Senate - 02/07/2012 Placed on Senate Legislative Calendar under General Orders. Calendar No. 317. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

Lake Tahoe Restoration Act of 2013

THOMAS, 113th Congress

Rep. Amodei, Mark E. [R-NV-2

2013-10-30

House - 01/09/2014 Referred to the Subcommittee on Crime, Terrorism, Homeland Security, and Investigations. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

Reduced toxicity with equivalent outcomes using three-dimensional volumetric (3DV) image-based versus nonvolumetric point-based (NV) brachytherapy in a cervical cancer population.

PubMed

Thomas, Kimberly M; Maquilan, Genevieve; Stojadinovic, Strahinja; Medin, Paul; Folkert, Michael R; Albuquerque, Kevin

Brachytherapy (BT) techniques have historically used a two-dimensional nonvolumetric (NV) system involving dose prescribed to a point fixed in space. We compared dosimetric, toxicity, and oncologic outcomes for volumetric planning (3DV) versus CT point-based planning. Patients treated with external beam radiation therapy and high dose rate (HDR) intracavitary BT were included (n = 71). Patients planned with NV BT treated from 2009 to 2011 (n = 37) were compared to patients planned with 3DV BT treated from 2012 to 2014 (n = 34). Investigators delineated volumes for organs at risk clinical target volumes for the 2009-2011 NV cohort. Acute and chronic toxicity data were graded. The mean HDR clinical target volume D90 received in the NV and 3DV cohorts were significantly different (p < 0.001). The mean dose to point A was significantly higher in the NV cohort than in the 3DV cohort (p < 0.001). There were significantly more Grade 3 or higher gastrointestinal toxicities in the NV cohort (p = 0.048). There was a nonsignificant trend toward improved oncologic outcomes for patients undergoing CT-based planning. 3DV BT allows for a significant reduction of dose to critical structures, resulting in decreased gastrointestinal toxicity, while delivering noninferior doses to the high-risk clinical target volume. Outcomes were improved in the 3D cohort trending toward statistical significance. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Midcontinent microcosm: Geology of the Atkins lake - Marengo falls area (Field trip 2)

USGS Publications Warehouse

Bjørnerud, Marcia; Cannon, William F.

2011-01-01

Archean and Proterozoic rocks exposed over about 16km2 between Atkins Lake and Coffee Lake in southeastern Bayfield County (Fig. 1) chronicle almost all of the major Precambrian geologic events in the history of the southern Superior Craton. The oldest rocks are part of a locally gneissic quartz monzonite complex, the Puritan Batholith, with an igneous Rb-Sr age of 2710+140 Ma (Sims et al., 1977). At the regional scale, this complex is part of one of the youngest Archean granite-greenstone belts in the Superior Province, and it intrudes greenstones of the Neoarchean Ramsay Formation. In the Atkins Lake – Marengo River area, the Puritan Batholith is nonconformably overlain by the Paleoproterozoic (ca. 2200 Ma) Bad River Dolomite. The Bad River Dolomite is in turn separated by an unconformity from rocks of the ca. 1875 Ma Menominee Group (Palms Formation and Ironwood Iron-formation), which locally contain mafic volcanic rocks and diabase sills (Cannon et al., 2008). These Paleoproterozoic rocks provide insight into climate and biogeochemical cycles during the transition to an oxidizing atmosphere (Bekker et al., 2006) and have deformational fabrics (folds, strong cleavage, local mylonite zones) that record the ca. 1850 Ma Penokean Orogeny. The youngest rocks in the area are Mesoproterozoic basaltic lava flows (Siemens Creek Volcanics, ca. 1110 Ma) and a layered mafic complex (the Mineral Lake Intrusion, also ca. 1100 Ma), both related to the Mid-continent Rift. All of the stratified units show static contact metamorphic textures near their contacts with the Mineral Lake Intrusion. Thus the area constitutes a microcosm of the regional bedrock geology, and the cross-cutting relationships among the units provide clear constraints on the relative timing of different phases of deformation and magmatism (Cannon etal., 2008, Bjørnerud, 2010a).

Catchment-mediated atmospheric nitrogen deposition drives ecological change in two alpine lakes in SE Tibet.

PubMed

Hu, Zhujun; Anderson, Nicholas John; Yang, Xiangdong; McGowan, Suzanne

2014-05-01

The south-east margin of Tibet is highly sensitive to global environmental change pressures, in particular, high contemporary reactive nitrogen (Nr) deposition rates (ca. 40 kg ha(-1)  yr(-1) ), but the extent and timescale of recent ecological change is not well prescribed. Multiproxy analyses (diatoms, pigments and geochemistry) of (210) Pb-dated sediment cores from two alpine lakes in Sichuan were used to assess whether they have undergone ecological change comparable to those in Europe and North America over the last two centuries. The study lakes have contrasting catchment-to-lake ratios and vegetation cover: Shade Co has a relatively larger catchment and denser alpine shrub than Moon Lake. Both lakes exhibited unambiguous increasing production since the late 19th to early 20th. Principle component analysis was used to summarize the trends of diatom and pigment data after the little ice age (LIA). There was strong linear change in biological proxies at both lakes, which were not consistent with regional temperature, suggesting that climate is not the primary driver of ecological change. The multiproxy analysis indicated an indirect ecological response to Nr deposition at Shade Co mediated through catchment processes since ca. 1930, while ecological change at Moon Lake started earlier (ca. 1880) and was more directly related to Nr deposition (depleted δ(15) N). The only pronounced climate effect was evidenced by changes during the LIA when photoautotrophic groups shifted dramatically at Shade Co (a 4-fold increase in lutein concentration) and planktonic diatom abundance declined at both sites because of longer ice cover. The substantial increases in aquatic production over the last ca. 100 years required a substantial nutrient subsidy and the geochemical data point to a major role for Nr deposition although dust cannot be excluded. The study also highlights the importance of lake and catchment morphology for determining the response of alpine lakes to

Hydrogeochemical characteristics and assessment of water quality in the Al-Saad Lake, Abha Saudi Arabia

NASA Astrophysics Data System (ADS)

Mallick, Javed

2017-10-01

Hydrogeochemical characteristics and assessment of water quality investigations have been carried out at Abha, located in Saudi Arabia, where Al-Saad Lake represents a rare example of natural endorheic lake. The ecosystem within and around the Al-Saad Lake including catchment area is of great social, cultural, aesthetic, environmental and economic values to Abha. Sampling and experiments of lake water has been carried out with the aim of characterizing the main physico-chemical parameters, such as DO, EC, TDS, Mg2+, Ca2+, Na+, K+, SO4 2-, Cl-, HCO3, NO3 - and F- concentration. The ordinary kriging (OK) method was used to produce the spatial patterns of water quality. The Result of DO (mean 5.38 mg/L) trend in Al-Saad Lake is not very encouraging as majority of the lake area is under DO stress or marginally above it. So, proper management strategies are needed to be formulated to protect flora and fauna of the lake. Furthermore, the chemical analysis results show the abundance of the major cations in the order Mg2+ > Ca2+ > Na+ > K+ whereas the abundance of anions are in the order SO4 2- > Cl- > HCO3 > NO3 - > F-. The result obtained in this investigation inferred that the cations in water i.e. sodium and iron are within the permissible limits but magnesium and potassium have exceeded the permissible limit. Whereas anions such as nitrate and fluoride are within the permissible range but chloride and sulphate have exceeded the permissible limits. The concentration of cation, magnesium (Mg) and potassium (K) in the lake water has exceeded the desirable range (30, 10 mg/L, respectively). This may be due to weathering and transported from rocks and particularly from sulphate deposits such as gypsum and anhydride and subsequently ends up in water. The concentration of anion, Sulphate (SO4) and chloride are above the desirable limit. The major source of bicarbonate are the carbonate rocks containing calcite (CaCO3) and dolomite (CaMg (CO3)2), Calcium (Ca) and Magnesium

77 FR 65332 - Proposed Modification of Class B Airspace; Las Vegas, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-26

...[deg]51'43'' W.); thence counterclockwise along the 16 DME arc to the point of beginning. Area E. That...). SUMMARY: This action proposes to modify the Las Vegas, NV, Class B airspace area to ensure the containment..., and reduce the potential for midair collision in the Las Vegas terminal area. DATES: Comments must be...

Pleistocene lake level changes in Western Mongolia

NASA Astrophysics Data System (ADS)

Borodavko, P. S.

2009-04-01

lake is 75 km long and 31 km wide. Its mean depth is 47 m, with the deepest point reaching 80 m, and its total water volume is 66,034 km3 and drainage basin 115,500 km2. The only water flowing into it is Galbiyn Hooloi. Hara-Us Nur Lake is a fresh-water (mineralization ca 107-348 mg/l, pH -7.8) basin situated in the Mongolian Great Lakes Depression [2]. Hara-Us Nur is fed by the Kobdo and Buyant rivers, which start in the Mongolian Altay, and outflows via the Chano-Hairkhan River into Hara-Us Nur Lake. Hara-Us Nur is divided by the Ak-Bashi Island into two subbasins. It has a water area of 1857 km2 with a length of 72.2 km and a maximum width of 27 km [4]. The maximum depth is 4 m and the average depth is ca 2 m [5,6]. The terraced lake shores are covered by steppe and desert vegetation. Pharagmites is abundant in the river deltas and close to the shore-line and the shallow-water littoral is covered by rich aquatic vegetation, including Myriophyllum verticulatum, Zannichelia pedunculata, Utricularia vulgaris [3]. Hara-Nur Lake is situated in the desert steppe subzone of the Mongolian Great Lakes Depression. The fresh-water Hara-Nur Lake receives inflow from Hara-Us Nur Lake via the Chano-Hairkhan River. There are two outflows from the lake one outflow is via a 10 km-long channel which flows to the Dzabhan River, which in turn flows into the closed Hyargas Lake. The other outflow is a small semi-permanent stream with flows southward into the closed brackish-water Dorgon Lake. Hara-Nur has a water area of 57,500 ha, with a length of 37 km and a maximum width of ca 24 km. The maximum depth is 7 m and the average depth is ca 4 m. The mean water mineralization is 260 mg/l and the pH is 8.0 [5]. The catchment area is ca 7,200,000 ha. Lake Ureg located in the Mongolian Altay at an altitude of 1425 m.a.s.1., this lake has an area 237.6 km2 and maximum depth of 48 m. Secchi disk transparency is to 8 m. Macrophyte beds cover up to 20 per cent of the lake area, with the common

Conditions affecting the release of phosphorus from surface lake sediments.

PubMed

Christophoridis, Christophoros; Fytianos, Konstantinos

2006-01-01

Laboratory studies were conducted to determine the effect of pH and redox conditions, as well as the effect of Fe, Mn, Ca, Al, and organic matter, on the release of ortho-phosphates in lake sediments taken from Lakes Koronia and Volvi (Northern Greece). Results were evaluated in combination with experiments to determine P fractionation in the sediment. The study revealed the major effect of redox potential and pH on the release of P from lake sediments. Both lakes showed increased release rates under reductive conditions and high pH values. The fractionation experiments revealed increased mobility of the reductive P fraction as well as of the NaOH-P fraction, indicating participation of both fractions in the overall release of sediment-bound P, depending on the prevailing environmental conditions. The results were assessed in combination with the release patterns of Fe, Mn, Ca, Al, and organic matter, enabling the identification of more specific processes of P release for each lake. The basic release patterns included the redox induced reductive dissolution of P-bearing metal oxides and the competitive exchange of phosphate anions with OH- at high pH values. The formation of an oxidized surface microlayer under oxic conditions acted as a protective film, preventing further P release from the sediments of Lake Volvi, while sediments from Lake Koronia exhibited a continuous and increased tendency to release P under various physicochemical conditions, acting as a constant source of internal P loading.

Authigenic carbonate precipitation in Lake Acigöl, a hypersaline lake in southwestern Turkey

NASA Astrophysics Data System (ADS)

Balci, Nurgul; Menekse, Meryem; Gül Karagüler, Nevin; Seref Sönmez, M.; Meister, Patrick

2014-05-01

Lake Acigöl (Bitter Lake) is a hypersaline lake in southwestern Turkey at an elevation of 836 m above sea level showing authigenic precipitation of several different carbonate mineral phases. It is a perennial lake and closed drainage basin where a semiarid continental climate dominates. Due to the extreme water chemistry (salinity 8-200 mg/l; SO4 112-15232 mg/l; Cl 290-35320 mg/l; Mg, 82-3425 mg/l; Ca 102-745 mg/l) unique microorganisms flourish in the lake. We studied microbial diversity from enrichment cultures and performed precipitation experiments using similar water chemistry and adding bacterial enrichment cultures from lake sediments in order to elucidate whether the mineral assemblages found in the lake can be reproduced. Experiments using moderately halophilic bacteria obtained from the lake sediments demonstrate the formation of various calcium-/magnesium-carbonates: hydromagnesite, dypingite, huntite, monohydrocalcite and aragonite. The relative amounts of different mineral phases, particularly monohydrocalcite, hydromagnesite and dypingite, could be controlled by varying the sulphate concentration in the media from 0 to 56 mM. The similar mineral assemblages identified in the sediments of Lake Acigöl and in the experiments point to similar thermodynamic conditions and kinetics of crystal growth. In particular, the similar spherical morphology points to a rapid crystal growth under strong kinetic inhibition, possibly by organic polymers that are commonly produced by microbial communities. Our results demonstrate that the authigenic carbonate paragenesis of hypersaline lakes as Lake Acigöl can be reproduced in halophilic bacterial cultures. The exact thermodynamic conditions and precipitation kinetics under seasonally changing water chemistry or in batch experiment, however, still have to be constrained in order to establish a microbial model for carbonate precipitation in such environments.

The AFRL MITLL WMT15 System: Theres More than OneWay to Decode It!

DTIC Science & Technology

2015-06-25

pages 376– 380 , Baltimore, Maryland, USA, June. Associ- ation for Computational Linguistics. Jacob Devlin, Rabih Zbib, Zhongqiang Huang, Thomas Lamar...LL/AFRL IWSLT-2014 MT system. In Pro- ceedings of the 11th International Workshop on Spo - ken Language Translation (IWSLT’14), Lake Tahoe, California

Operations Under the Airport and Airway Development Act of 1970.

DTIC Science & Technology

1980-01-01

Orange County Air (ANCLUC). John Wayne Airport Ar taeer 74,a25 (Orange county)rri Santa Rosa General Airport Master Plan. Sonoma county Aviation...Rosa 08 $ 152,095 Reconstruct and mark taxiways; Sonoma County drainage; relocate taxiway lighting. South Lake Tahoe 05 199,460 Acquire crash/fire

75 FR 877 - Cancellation of the South Valley Facilities Expansion Project-Clark County, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-06

... DEPARTMENT OF INTERIOR Bureau of Reclamation Cancellation of the South Valley Facilities Expansion Project-- Clark County, NV AGENCY: Bureau of Reclamation, Interior. ACTION: Cancellation of Notice of Intent to prepare the Environmental Impact Statement. SUMMARY: The Bureau of Reclamation, together with...

Evaluation of ERTS data for certain oceanographic uses. [precipitation of calcium carbonate in Lake Michigan, Lake Erie, and Lake Ontario

NASA Technical Reports Server (NTRS)

Strong, A. E. (Principal Investigator)

1974-01-01

The author has identified the following significant results. According to Lake Michigan records, the pH levels have been steadily increasing as the lake becomes more eutrophic. Numerous upwellings during the summer of 1973, beginning with the late July event, appear to be triggering a chemical precipitation of calcium carbonate. The upwelling provides abundant carbon dioxide into the surface water and results in massive blooms of phytoplankton. As the CO2 is utilized by these microscopic plants the pH is increased (acidity decreases) and CaCO3 no longer is able to remain in solution. The precipitation takes place where the phytoplankton are living, near depths of 10 meters. Therefore, the whiting observed by ERTS-1 is only seen in the green band, as red cannot penetrate but a few meters. With these whitings, secci disc readings lower in July from 10-15 meters to 3-5 meters and green, milky water is observed by research vessels. It appears that whitings have been becoming more frequent since the middle 60's but until ERTS-1 the extent had never been realized. Calcium levels are too low, presently, for a similar precipitate in Lakes Huron or Superior. However, whitings have been seen by ERTS-1 in Lakes Erie and Ontario where the calcium ion and pH levels are more like those found in Lake Michigan.

Climatic and limnologic setting of Bear Lake, Utah and Idaho

USGS Publications Warehouse

Dean, W.E.; Wurtsbaugh, W.A.; Lamarra, V.A.

2009-01-01

Bear Lake is a large alkaline lake on a high plateau on the Utah-Idaho border. The Bear River was partly diverted into the lake in the early twentieth century so that Bear Lake could serve as a reservoir to supply water for hydropower and irrigation downstream, which continues today. The northern Rocky Mountain region is within the belt of the strongest of the westerly winds that transport moisture during the winter and spring over coastal mountain ranges and into the Great Basin and Rocky Mountains. As a result of this dominant winter precipitation pattern, most of the water entering the lake is from snowmelt, but with net evaporation. The dominant solutes in the lake water are Ca 2+, Mg2+, and HCO32-, derived from Paleozoic carbonate rocks in the Bear River Range west of the lake. The lake is saturated with calcite, aragonite, and dolomite at all depths, and produces vast amounts of carbonate minerals. The chemistry of the lake has changed considerably over the past 100 years as a result of the diversion of Bear River. The net effect of the diversion was to dilute the lake water, especially the Mg2+ concentration. Bear Lake is oligotrophic and coprecipitation of phosphate with CaCO3 helps to keep productivity low. However, algal growth is colimited by nitrogen availability. Phytoplankton densities are low, with a mean summer chlorophyll a concentration of 0.4 mg L-1. Phytoplankton are dominated by diatoms, but they have not been studied extensively (but see Moser and Kimball, this volume). Zooplankton densities usually are low (<10 L-1) and highly seasonal, dominated by calanoid copepods and cladocera. Benthic invertebrate densities are extremely low; chironomid larvae are dominant at depths <30 m, and are partially replaced with ostracodes and oligochaetes in deeper water. The ostracode species in water depths >10 m are all endemic. Bear Lake has 13 species of fi sh, four of which are endemic. Copyright ?? 2009 The Geological Society of America.

Hydrogeochemistry of Maine seepage lakes and related groundwaters

NASA Astrophysics Data System (ADS)

Stauffer, Robert E.; Wittchen, Bruce D.

1992-10-01

Southeastern Maine contains numerous small seepage lakes (no perennial surface inflows or outflows), set in felsic, glacial deposits (eskers, pitted outwash, glacio-marine deltaic terraces) dating from the Wisconsin glacial retreat ca. 12 500 years B.P. The modern landscape is either forested or maintained as low blueberry heath by semi-annual mowing and burning. Although local precipitation is currently moderately acidic (volume-weighted pH ≈ 4.5), spring waters issuing from the glacial deposits are only weakly acidic (6.1 < pH < 7.0), and bicarbonate-buffered (120 to 300 mmol m -3) on account of tertiary weathering by dissolved CO 2. The order of mobility (denudation rate) for base cations (BC) is: Ca > Na > Mg > K, the same as for upland granitic terrane in the same region. Springwater composition is temporally stable but geographically variable. The most dilute springwaters drain blueberry barrens. Here, chemical weathering is limited by available acidity as evidenced by the relatively high final pHs (> 6.3) and low concentrations of strong oxy-anions (nitrate, sulfate) and dissolved inorganic carbon (DIC < 250 μM). Closely neighboring lakes often range widely in alkalinity, BC, and F, depending on their connection to the local groundwater system. Tracer analysis indicates seepage inflow is equal to 5-50 cm year -1 for typical regional seepage lakes, vs. higher rates (> 100 cm year -1) for groundwater discharge lakes. Approximately 88% of Si inputs to regional seepage lakes is retained in the sediments. Non-marine sulfate is lowest in groundwater discharge lakes containing the highest concentrations of BC and F, and featuring the shortest hydraulic residence times, suggesting that S retention in lake sediments is currently less efficient than in the adjoining terrestrial soils and vegetation.

77 FR 55787 - Proposed Flood Elevation Determinations for the City of Carson City, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-11

...-2011-0002; Internal Agency Docket No. FEMA-B-1233] Proposed Flood Elevation Determinations for the City of Carson City, NV AGENCY: Federal Emergency Management Agency, DHS. ACTION: Proposed rule... concerning proposed flood elevation determinations for the City of Carson City, Nevada. DATES: This...

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...

Effects of urban development on ant communities: implications for ecosystem services and management

Treesearch

M.P. Sanford; Patricia N. Manley; Dennis D. Murphy

2009-01-01

Research that connects the effects of urbanization on biodiversity and ecosystem services is lacking. Ants perform multifarious ecological functions that stabilize ecosystems and contribute to a number of ecosystem services. We studied responses of ant communities to urbanization in the Lake Tahoe basin by sampling sites along a gradient...

Pacific southwest United States Holocene summer paleoclimate inferred from sediment calcite oxygen isotopes (Lake Elsinore, CA)

NASA Astrophysics Data System (ADS)

Kirby, M.; Patterson, W. P.; Lachniet, M. S.; Anderson, M.; Noblet, J. A.

2017-12-01

Records of past climate inform on the natural range and mechanisms of climate change. In the arid Pacific southwest United States (pswUS), there exist a variety of Holocene records that infer past winter conditions (moisture and/or temperature). Holocene records of summer climate, however, are rare excepting short-lived (<500-1000 yrs) tree ring PDSIs and some pollen-inferred temperature reconstructions. As climate changes due to anthropogenic forcing, the severity of drought is expected to increase in the already water-stressed pswUS. Hot droughts are of considerable concern as summer temperatures rise. As a result, understanding how summer conditions changed in the past is critical to understanding future predictions under varied climate forcings. Here, we present a 9800 year delta-18O(calcite) record from Lake Elsinore, CA. This isotope record is interpreted to reflect late-spring to summer conditions, especially evaporation. Modern water isotope data support this interpretation. Our results reveal a three-part Holocene consisting of a highly evaporative early Holocene, a cooler mid-Holocene, and evaporative late Holocene. Coupled with an inferred winter wetness (run-off) record from Kirby et al. (2010), we estimate the severity of centennial scale Holocene dryness (i.e. dry winters plus hot summers = severe drought). The most severe droughts occur in the early Holocene, decline in the mid-Holocene, and return in the late Holocene. An independently dated isotope record from Lake Elsinore's littoral zone (Kirby et al. 2004) shows similar changes providing confidence in our longer record. Various forcing mechanisms are examined to explain the Elsinore summer record including insolation, Pacific SSTs, and trace gas radiative forcing.

5 CFR 531.603 - Locality pay areas.

Code of Federal Regulations, 2013 CFR

2013-01-01

... of the Sacramento—Arden-Arcade—Yuba City, CA-NV CSA, plus Carson City, NV; (30) San Diego-Carlsbad-San Marcos, CA—consisting of the San Diego-Carlsbad-San Marcos, CA MSA; (31) San Jose-San Francisco...

5 CFR 531.603 - Locality pay areas.

Code of Federal Regulations, 2014 CFR

2014-01-01

... of the Sacramento—Arden-Arcade—Yuba City, CA-NV CSA, plus Carson City, NV; (30) San Diego-Carlsbad-San Marcos, CA—consisting of the San Diego-Carlsbad-San Marcos, CA MSA; (31) San Jose-San Francisco...

5 CFR 531.603 - Locality pay areas.

Code of Federal Regulations, 2012 CFR

2012-01-01

... of the Sacramento—Arden-Arcade—Yuba City, CA-NV CSA, plus Carson City, NV; (30) San Diego-Carlsbad-San Marcos, CA—consisting of the San Diego-Carlsbad-San Marcos, CA MSA; (31) San Jose-San Francisco...

Occurrence of phosphorus, iron, aluminum, silica, and calcium in a eutrophic lake during algae bloom sedimentation.

PubMed

Li, Guolian; Xie, Fazhi; Zhang, Jin; Wang, Jingrou; Yang, Ying; Sun, Ruoru

2016-09-01

Phosphorus (P) in a water body is mainly controlled by the interaction between surface sediment and the overlying water column after the complete control of external pollution. Significant enhancement of P in a water body would cause eutrophication of lakes. Thus, a better understanding is needed of the occurrences of P between the sediment and water column in eutrophic lakes. Here, we measured total phosphorus (TP) and major elements (Fe, Al, Ca, Mn, Si) in the water column, and total nitrogen, organic matter, TP and major oxides (Fe 2 O 3 , Al 2 O 3 , CaO, SiO 2 ) in surface sediment of Chaohu Lake, a continuously eutrophic lake. The results showed that the rank of TP levels was western lake > eastern lake > southern lake. There were significantly positive correlations between TP (including water TP and sedimentary TP) and Fe, Al, Mn, while the correlation coefficients between water TP and sedimentary TP were -0.43, -0.41 and 0.18 for the western, eastern and southern lake respectively. The negative and significant correlations of water TP and sedimentary TP may indicate that the risk of sedimentary P release was great in the western and eastern lake during algae bloom sedimentation, while the southern lake showed weak P exchange between the sediment and water column.

Geochemistry of ikaite formation at Mono Lake, California: Implications for the origin of tufa mounds

NASA Astrophysics Data System (ADS)

Council, Todd C.; Bennett, Philip C.

1993-11-01

The mineral ikaite (CaCO3 ṡ 6H2O), not previously observed in lake environments, precipitates seasonally along the shore of Mono Lake, California, where Ca-HCO3 spring water mixes with cold Na-CO3 lake water. During the winter, cold water temperatures and high concentrations of PO43- and organic carbon inhibit calcite precipitation, allowing the metastable ikaite to form. During the spring warming, however, ikaite decomposes to form calcium carbonate and water, occasionally leaving pseudomorphs of the primary precipitate. The identification of modern ikaite suggests that both Pleistocene and Holocene tufas in the Mono basin originally precipitated as ikaite. This mineral may also form in other lake environments, but rapid recrystallization after warming destroys the physical, chemical, and isotopic evidence of formation, and alters the geochemical record.

The Kramer deposit of southern California--Preliminary insights on the origins of zoned lacustrine evaporite borate deposits

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

Swihart, G.H.; McBay, E.H.; Smith, D.H.

1992-01-01

Lacustrine evaporite borate deposits span the range from mineralogically unzoned or poorly zoned to concentrically or complexly zoned types. Deposits often contain an inner ulexite or probertite (Na-Ca borates) zone and an outer colemanite (Ca borate) zone. A few deposits contain an innermost borax (Na borate) zone. Boron isotopic analyses of core material from the zoned borax-ulexite-colemanite Kramer deposit have been made with the aim of providing a better understanding of the processes of zone formation. Samples from 6 depths over a 63 foot interval in the borax zone yield a [delta] B-11 range of +0.1 to +2.3 permil. Twomore » samples in the portion of the ulexite zone below the borax zone, vertically separated from one another by 20 feet, yield identical results of [delta]B-11 = [minus]2.1 permit. Three ulexite samples from a 10 foot interval above the borax zone produced results in the range [delta]B-11 = [minus]4.6 to [minus]5.5 permil. A number of possible origins for ulexite at Kramer have been proposed: (1) primary precipitation from the lake brines; (2) postdepositional alteration of the borax zone margin by Ca-rich groundwater; (3) mixing of seeping lake brines and Ca-rich groundwater in muds around the lake. Given the small variation in B isotopic composition exhibited in the borax zone, mechanisms 1 and 2 would produce upper and lower portions of the ulexite zone with similar isotopic compositions. In the third scenario, the difference in composition of the upper and lower ulexites could be due to distance from the lake and relative proportions of seeped lake brine (B-11-rich) and clay adsorbed B (B-10-rich). Furthermore, the cotton ball form of the ulexite in this core is identical to that of ulexite forming today just beneath the surface of dry lakes in NV and CA.« less

The effects of experimental lake acidification on the reproductive success of tree swallows

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

St. Louis, V.L.

1992-01-01

The effects of lake acidification on reproductive success of tree swallows (Tachycineta bicolor) breeding near experimentally acidified and unmanipulated reference lakes at the Experimental Lake Area (ELA) were studied. Tree swallows are aerial insectivores that commonly breed near water and forage on emergent insects. Predictions suggest that avian food abundance and quality may be altered due to acidification. Breeding swallows foraged on chironomids emerging at their nest-site lakes before searching for food elsewhere. Among the calcium-rich items consumed by the swallows, fish bones were most numerous, followed by crayfish exoskeleton, clam shell, and bird eggshell. We found significantly fewer calcium-richmore » items in the stomachs of nestlings from acid lakes than in those from reference lakes. Chironomid species were significantly more abundant in acid lakes, while the Chironominae were less numerous. Biomass of emerging chironomids either increased significantly following acidification, or was not different from that of reference lakes. Concentrations of Al, Ca, Mn, and Zn were on average higher in chironomids from a number of the acid lakes than in chironomids from reference lakes. Calcium concentrations in chironomids from the most acid lake were significantly lower, suggesting that Ca may be difficult to sequester at low pH levels. Hepatic concentrations of metallothioneins in tree swallow nestlings were negatively correlated with pH of the nest-site lake. Additive concentrations of Cu and Zn in the liver were correlated with liver MT concentrations, but Cd was not. Near acidified lakes, eggs were smaller in certain dimensions, hatching success was lower, certain nestling body characters were smaller, nestling wing length was shorter, and growth functions were different than near unmanipulated reference lakes. Clearly even non-aquatic organisms are affected by acidification of freshwater ecosystems.« less

Elucidation of riverine and lacustrine dissolved organic matter (DOM) composition using comprehensive GC×GC time-of-flight mass spectrometry (GC×GC-TOF-MS)

NASA Astrophysics Data System (ADS)

Ball, G. I.; Goldberg, S. J.; Aluwihare, L. I.

2012-12-01

measurements indicative of terrestrial OM loading, such as increased 1H-NMR resonance intensities for methoxy and aromatic-linked hydrogens and lower δ13C values more consistent with C3 plant versus algal sources.igure 1: Oxidized and derivatized SPE-DOM isolated from the Upper Truckee River, South Lake Tahoe, CA, and visualized in two dimensions.

Lake level fluctuations and catchment dynamics at Lake Ohrid (Macedonia, Albania) during MIS6 and MIS5

NASA Astrophysics Data System (ADS)

Francke, Alexander; Wagner, Bernd; Just, Janna; Sadori, Laura; Masi, Alessia; Vogel, Hendrik; Lindhorst, Katja; Krastel, Sebastian; Dosseto, Anthony; Rothacker, Leo; Leicher, Niklas; Gromig, Raphael

2016-04-01

Lake Ohrid, presumably the oldest lake of Europe located at the border of Macedonia and Albania, is about 30 km long, 15 km wide, and up to 290 m deep. In 2013, an ICDP deep drilling campaign was carried out under the umbrella of the Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) project. At the main drill site (DEEP) in the central part of Lake Ohrid, the uppermost 568 m from a total sediment fill of ca. 700 m were recovered. Initial data from core catcher material indicate that the sediment sequence covers more than 1.2 million years. An age model, which is based on 11 tephrostratigragphic tie points and on tuning of biogeochemical proxy data versus orbital parameters reveals that that the upper 247 m of the DEEP site sequence cover the time period between 637 ka (MIS16) and the present. Inhere, we present sedimentological, (bio-)geochemical, environmental magnetic, and pollen data for the time period between MIS6 (191 ka) and MIS5 (71 ka). The data imply that MIS6 was one of the most severe glacial periods, while MIS5 was likely one of the more pronounced interglacial during the past 637 kyrs. The repercussions of these high amplitude climatic and environmental variations during this period are recorded in the sedimentological archive of Lake Ohrid. Previous studies based on hydro-acoustic and sediment core data from the northeastern part of the lake basin have shown that the lake level of Lake Ohrid was likely 60 m lower during MIS6. The ˜60 m lower lake level at Lake Ohrid during MIS6 can at least partly be explained by the ongoing subsidence, which persists in the basin until today. However, in the DEEP site sediments, the MIS6/MIS5 transition occurs at ca. 50 m sediment depth. This implies that climate-induced lake level fluctuation at Lake Ohrid are less severe compared for example to Lake Van (Turkey), were a 260 m lower lake level has been reported for the Younger Dryas. The imprint of the environmental variations between

Development and Deployment of an Aerospace Recommended Practice (ARP) Compliant Measurement System for nvPM Certification Measurements of Aircraft Engines - Current Status.

NASA Astrophysics Data System (ADS)

Whitefield, P. D.; Hagen, D. E.; Lobo, P.; Miake-Lye, R. C.

2015-12-01

The Society of Automotive Engineers (SAE) Aircraft Exhaust Emissions Measurement Committee (E-31) has published an Aerospace Information Report (AIR) 6241 detailing the sampling system for the measurement of non-volatile particulate matter (nvPM) from aircraft engines (SAE 2013). The system is designed to operate in parallel with existing International Civil Aviation Organization (ICAO) Annex 16 compliant combustion gas sampling systems used for emissions certification from aircraft engines captured by conventional (Annex 16) gas sampling rakes (ICAO, 2008). The SAE E-31 committee is also working to ballot an Aerospace Recommended Practice (ARP) that will provide the methodology and system specification to measure nvPM from aircraft engines. The ARP is currently in preparation and is expected to be ready for ballot in 2015. A prototype AIR-compliant nvPM measurement system - The North American Reference System (NARS) has been built and evaluated at the MSTCOE under the joint sponsorship of the FAA, EPA and Transport Canada. It has been used to validate the performance characteristics of OEM AIR-compliant systems and is being used in engine certification type testing at OEM facilities to obtain data from a set of representative engines in the fleet. The data collected during these tests will be used by ICAO/CAEP/WG3/PMTG to develop a metric on which on the regulation for nvPM emissions will be based. This paper will review the salient features of the NARS including: (1) emissions sample transport from probe tip to the key diagnostic tools, (2) the mass and number-based diagnostic tools for nvPM mass and number concentration measurement and (3) methods employed to assess the extent of nvPM loss throughout the sampling system. This paper will conclude with a discussion of the recent results from inter-comparison studies conducted with other US - based systems that gives credence to the ARP's readiness for ballot.

Electron Paramagnetic Resonance of a Single NV Nanodiamond Attached to an Individual Biomolecule

NASA Astrophysics Data System (ADS)

Teeling-Smith, Richelle M.; Jung, Young Woo; Scozzaro, Nicolas; Cardellino, Jeremy; Rampersaud, Isaac; North, Justin A.; Šimon, Marek; Bhallamudi, Vidya P.; Rampersaud, Arfaan; Johnston-Halperin, Ezekiel; Poirier, Michael G.; Hammel, P. Chris

2016-05-01

A key limitation of electron paramagnetic resonance (EPR), an established and powerful tool for studying atomic-scale biomolecular structure and dynamics is its poor sensitivity, samples containing in excess of 10^12 labeled biomolecules are required in typical experiments. In contrast, single molecule measurements provide improved insights into heterogeneous behaviors that can be masked by ensemble measurements and are often essential for illuminating the molecular mechanisms behind the function of a biomolecule. We report EPR measurements of a single labeled biomolecule that merge these two powerful techniques. We selectively label an individual double-stranded DNA molecule with a single nanodiamond containing nitrogen-vacancy (NV) centers, and optically detect the paramagnetic resonance of NV spins in the nanodiamond probe. Analysis of the spectrum reveals that the nanodiamond probe has complete rotational freedom and that the characteristic time scale for reorientation of the nanodiamond probe is slow compared to the transverse spin relaxation time. This demonstration of EPR spectroscopy of a single nanodiamond labeled DNA provides the foundation for the development of single molecule magnetic resonance studies of complex biomolecular systems.

Climatic change and evaporative processes in the development of Common Era hypersaline lakes, East Antarctica: A study of Lake Suribati

NASA Astrophysics Data System (ADS)

Nakashima, H.; Seto, K.; Katsuki, K.; Kaneko, H.; yamada, K.; Imura, S.; Dettman, D. L.

2011-12-01

The Antarctic continent was uplifted by glacioisostatic rebound due to the regression of ice sheets after the last glacial period. Today's saline lakes were formed in shallow basins originally below sea level. Antarctic hypersaline lakes are formed by concentration of isolated seawater bodies as affected by recent climate change. Many saline lakes are found in the ice-free area of the Soya coast, East Antarctica. Lake Suribati is located in Sukarvsnes on the Soya coast. It is a hypersaline lake with maximum salinity ~200 psu, and an observable stable halocline at 7~12m depth. This study uses Lake Suribati sediment core Sr4C-01, collected by the 46th Japanese Antarctica Research Expedition, to examine the relationship of climatic change to evaporative processes and solute concentration in Lake Suribati in the Common Era. Sr4C-01 core was collected at 9.53m water depth in Lake Suribati in 2005 (core length is 63cm). This core primarily consists of black mud and laminated black organic mud. In the interval from 10 to 24cm below the sediment surface evaporite crystals occur. The age of the Sr4C-01 core bottom is estimated to be ~3,500 cal yrs BP, based on AMS carbon-14 dating at 6 core horizons. The evaporite crystals were indentified as aragonite based on XRD. Total inorganic carbon (TIC) content is low, around 0.5%, throughout the Sr4C-01 core, with higher values, approximately 1~4%, in two intervals, 57~52cm and 29~10cm core depth. Variation in CaO content tracks TIC content. We suggest that synchronous change in CaO and TIC contents indicate the vertical change in the amount of aragonite. Two intervals of evaporite precipition imply two intervals of evaporation and concentration of lake water. Hypersaline lake conditions did not occur soon after the isolation from the sea, rather these occurred under repeated concentration and dilution of lake water. Dilution of saline lake water could occur through the inflow of melt water from local snow or ice, indicating a warm

Monitoring climate signal transfer into the varved lake sediments of Lake Czechowskie, Poland

NASA Astrophysics Data System (ADS)

Groß-Schmölders, Miriam; Ott, Florian; Brykała, Dariusz; Gierszewski, Piotr; Kaszubski, Michał; Kienel, Ulrike; Brauer, Achim

2015-04-01

In 2012 we started a monitoring program at Lake Czechowskie, Poland, because the lake comprises a long Holocene time series of calcite varves until recent times. The aim of the program is to understand how environmental and climatic conditions influence the hydrological conditions and, ultimately, the sediment deposition processes of the lake. Lake Czechowskie is located in the north of Poland in the Pomeranian Lake District and is part of the national park Tuchola Forest. The landscape and the lake is formed by the glacier retreat after the last glaciation (Weichselian). Lake Czechowskie is a typical hardwater lake and has a length of 1.4 km, an average width of 600 m and a lake surface area of ca 4 km. The maximum depth of 32 m is reached in a rather small hollow in the eastern part of the lake. Two different types of sediment traps provide sediment samples with monthly resolution from different water depths (12m, 26m). In addition, hydrological data including water temperature in different depths, water inflow, throughflow and outflow and the depth of visibility are measured. These data allow to describe strength and duration of lake mixing in spring and autumn and its influence on sedimentation. The sediment samples were analyzed with respect to their dry weight (used to calculate mean daily sediment flux), their inorganic and organic carbon contents, the stable C- and O-isotopes of organic matter and calcite as well as N-isotopes of organic matter. For selected samples dominant diatom taxa are determined. Our first results demonstrate the strong influence of the long winter with ice cover until April in 2013 on the sedimentation. A rapid warming in only 9 days starting on April 9th from -0,3 C° to 15,2 C° resulted in fast ice break-up and a short but intensive lake mixing. In consequence of this short mixing period a strong algal bloom especially of Fragilaria and Crysophycea commenced in April and had its maximum in May. This bloom further induced biogenic

The lacustrine carbon cycle as illuminated by the waters and sediments of two hydrologically distinct headwater lakes in North-Central Minnesota, U.S.A

USGS Publications Warehouse

Dean, W.E.; Schwalb, A.

2002-01-01

The accumulation rates of CaCO3 and organic carbon (OC) in lake sediments are delicately balanced between production in the epilimnion and destruction in the hypolimnion. The cycling of these two forms of carbon makes a "carbon pump" that greatly affects the biogeochemical cycles of other elements. To further understand these biogeochemical dynamics, the lakes, streams, and wetlands of the Shingobee River headwater area of north-central Minnesota have been subjected to intensive hydrologic and biogeochemical studies. Williams Lake, situated close to the highest point in the regional flow system, is hydrologically closed, with no surface inlet or outlet, and ground water and precipitation as the only sources of water. Shingobee Lake, situated at the lowest point in the regional flow system, has the Shingobee River as an inlet and outlet. The surface waters of both lakes are oversaturated, and the bottom waters undersaturated, with respect to CaCO3 during the summer. The small amount of CaCO3 that is precipitated in the epilimnion of Williams Lake during the summer is dissolved in the undersaturated hypolimnion and sediments with the result that no CaCO3 is incorporated into the profundal surface sediments. Because of the high phytoplankton productivity of Shingobee Lake, sufficient CaCO3 is produced in the epilimnion that large amounts survive the corrosive hypolimnion and sediments, and an average of 46 wt. % accumulates in surface sediments. Another consequence of higher phytoplankton productivity in Shingobee Lake is that the hypolimnion becomes oxygen deficient within a month after overturn in both the spring and fall. Because of reducing conditions that develop in the hypolimnion of Shingobee Lake, high concentrations of dissolved Fe and Mn accumulate there during summer stratification. Precipitation of Fe and Mn oxyhydroxides during periods of fall and spring overturn results in high concentrations of Fe and Mn in surface sediments. In Williams Lake, high

Effect of Mg/Ca ratios on microbially induced carbonate precipitation

NASA Astrophysics Data System (ADS)

Balci, Nurgul; Demirel, Cansu; Seref Sonmez, M.; Kurt, M. Ali

2016-04-01

Influence of Mg/Ca ratios on microbially induced carbonate mineralogy were investigated by series of experiments carried out under various environmental conditions (Mg/Ca ratio, temperature and salinity). Halophilic bacterial cultures used for biomineralization experiments were isolated from hypersaline Lake Acıgöl (Denizli, SW Turkey), displaying extreme water chemistry with an average pH around 8.6 (Balci eta l.,2015). Enriched bacterial culture used in the experiments consisted of Halomonas saccharevitans strain AJ275, Halomonas alimentaria strain L7B; Idiomarina sp. TBZ29, 98% Idiomarina seosensis strain CL-SP19. Biomineralization experiments were set up using above enriched culture with Mg/Ca ratios of 0.05, 1, 4 and 15 and salinity of 8% and 15% experiments at 30oC and 10oC. Additionally, long-term biomineralization experiments were set up to last for a year, for Mg/Ca=4 and Mg/Ca=15 experiments at 30oC. For each experimental condition abiotic experiments were also conducted. Solution chemistry throughout incubation was monitored for Na, K, Mg, Ca, bicarbonate, carbonate, ammonium and phosphate for a month. At the end of the experiments, precipitates were collected and morphology and mineralogy of the biominerals were investigated and results were evaluated using the software DIFFRAC.SUITE EVA. Overall the preliminary results showed chemical precipitation of calcite, halite, hydromagnesite and sylvite. Results obtained from biological experiments indicate that, low Mg/Ca ratios (0.05 and 1) favor chlorapatite precipitation, whereas higher Mg/Ca ratios favor struvite precipitation. Biomineralization of dolomite, huntite and magnesite is favorable at high Mg/Ca ratios (4 and 15), in the presence of halophilic bacteria. Moreover, results indicate that supersaturation with respect to Mg (Mg/Ca=15) combined with NaCl (15%) inhibits biomineralization and forms chemical precipitates. 15% salinity is shown to favor chemical precipitation of mineral phases more than

The last interglaciation at Owens Lake, California; Core OL-92

USGS Publications Warehouse

Bischoff, James L.

1998-01-01

Owens Lake, located at the eastern base of the central Sierra Nevada (Fig. 1), was the terminus of the Owens River prior to the lake's complete desiccation shortly after 1913 due to river diversion by the City of Los Angeles. During earlier wetter cycles, the lake overflowed to fill a series of downstream basins including China Lake Basin, Searles Valley, Panamint Valley, and ultimately, Death Valley (Smith and Street-Perrott, 1983). In 1992 the U.S. Geological Survey drilled a 323-m-deep core (OL-92) into Owens Lake sediments near the depocenter of the basin to obtain a continuous record of silty-clay sediment spanning the last 800,000 yrs. A multi-parameter reconnaissance study of the entire core (ca 7000-yr resolution), was reported in a 13-chapter summary volume (Smith and Bischoff, 1997). A document containing the numerical and other detailed forms of raw data collected by that volume's authors was prepared earlier (Smith and Bischoff, 1993). The reconnaissance study provided an approximate time-depth model for the entire core, based on radiocarbon dates from the top 31m, the Bishop Ash (759,000 yrs) at 304 m, ten within-Brunhes paleomagnetic excursions, and a compaction-corrected mass-accumulation rate of 51.4 g/cm/l000yr (Bischoff et al., 1997a). Application of this model to observed sediment parameters indicates that Owens Lake was saline, alkaline, and biologically productive at times of decreased water-flow, and was generally hydrologically flushed and relatively unproductive during times of increased water-flow. Grain size, abundance of CaCO3, organic carbon, clay mineralogy, cation-exchange capacity of the clay fraction, fossil pollen, fish, ostracodes, and diatoms (see summary by Smith et al., 1997) all show cyclic variation down the core. CaCO3 abundance, in particular, strongly reflects an approximately 100 ka dominant cycle, characteristic of global ice-volume indicated by the MIS δ18O record. Four of the last five marine isotope terminations are

75 FR 51841 - Notice of Realty Action: Proposed sale of Public Lands, Churchill County, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-23

... Lands, Churchill County, NV AGENCY: Bureau of Land Management, Interior. ACTION: Notice of realty action... value, approximately 800 acres of public lands in Churchill County, Nevada, through direct [email protected] . SUPPLEMENTARY INFORMATION: The following described public lands in Churchill County...

Dynamic coupling of volcanic CO2 flow and wind at the HorseshoeLake tree kill, Mammoth Mountain, CA

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

Lewicki, J.L.; Hilley, G.E.; Tosha, T.

2006-11-20

We investigate spatio-temporal relationships between soilCO2 flux (FCO2), meteorological variables, and topography over a ten-dayperiod (09/12/2006 to 09/21/2006) at the Horseshoe Lake tree kill,Mammoth Mountain, CA. Total CO2 discharge varied from 16 to 52 t d-1,suggesting a decline in CO2 emissions over decadal timescales. Weobserved systematic changes in FCO2 in space and time in association witha weather front with relatively high wind speeds from the west and lowatmospheric pressures. The largest FCO2 changes were observed inrelatively high elevation areas. The variations in FCO2 may be due todynamic coupling of wind-driven airflow through the subsurface and flowof source CO2 at depth.more » Our results highlight the influence of weatherfronts on volcanic gas flow in the near-surface environment and how thisinfluence can vary spatially within a study area.« less

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

Late Neolithic Mondsee Culture in Austria: living on lakes and living with flood risk?

NASA Astrophysics Data System (ADS)

Swierczynski, T.; Lauterbach, S.; Dulski, P.; Brauer, A.

2013-07-01

Neolithic and Bronze Age lake dwellings in the European Alps became recently protected under the UNESCO World Heritage. However, only little is known about the cultural history of the related pre-historic communities, their adaptation strategies to environmental changes and particularly about the almost synchronous decline of many of these settlements around the transition from the Late Neolithic to the Early Bronze Age. For example, there is an ongoing debate whether the abandonment of Late Neolithic lake dwellings at Lake Mondsee (Upper Austria) was caused by unfavourable climate conditions or a single catastrophic event. Within the varved sediments of Lake Mondsee, we investigated the occurrence of intercalated detrital layers from major floods and debris flows to unravel extreme surface runoff recurrence during the Neolithic settlement period. A combination of detailed sediment microfacies analysis and μXRF element scanning allows distinguishing debris flow and flood deposits. A total of 60 flood and 12 debris flow event layers was detected between 7000 and 4000 varve years (vyr) BP. Compared to the centennial- to millennial-scale average, a period of increased runoff event frequency can be identified between 5900 and 4450 vyr BP. Enhanced flood frequency is accompanied by predominantly siliciclastic sediment supply between ca. 5500 and 5000 vyr BP and enhanced dolomitic sediment supply between 4900 and 4500 vyr BP. A change in the location and the construction technique of the Neolithic lake dwellings at Lake Mondsee can be observed during the period of higher flood frequency. While lake dwellings of the first settlement period (ca. 5800-5250 cal. yr BP) were constructed directly on the wetlands, later constructions (ca. 5400-4700 cal. yr BP) were built on piles upon the water, possibly indicating an adaptation to either increased flood risk or a general increase of the lake level. However, our results also indicate that other than climatic factors (e

76 FR 35371 - Proposed Modification of the Las Vegas, NV, Class B Airspace Area; Public Meetings

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-17

... October 10, 2011. ADDRESSES: (1) The meeting on Thursday, August 18, 2011, will be held at Centennial High School, 10200 Centennial Parkway, Las Vegas, NV 89149; (2) The meeting on Tuesday, August 23, 2011, will...

43 CFR 419.4 - What specific provisions govern operations of the reservoirs?

Code of Federal Regulations, 2013 CFR

2013-10-01

... water rights, imported water, remaining water of the Truckee River, and emergencies Sections 1.A through... Sections 4.A through 4.G. Operation of Floriston Rate and Project Water Sections 5.A through 5.E. Truckee River and Lake Tahoe Basin Allocation and Accounting Sections 6.A through 6.E. Credit Water...

43 CFR 419.4 - What specific provisions govern operations of the reservoirs?

Code of Federal Regulations, 2014 CFR

2014-10-01

... water rights, imported water, remaining water of the Truckee River, and emergencies Sections 1.A through... Sections 4.A through 4.G. Operation of Floriston Rate and Project Water Sections 5.A through 5.E. Truckee River and Lake Tahoe Basin Allocation and Accounting Sections 6.A through 6.E. Credit Water...

75 FR 34636 - Safety Zone; Jameson Beach 4th of July Fireworks Display

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-18

...-AA00 Safety Zone; Jameson Beach 4th of July Fireworks Display AGENCY: Coast Guard, DHS. ACTION... waters of Lake Tahoe, for the Jameson Beach 4th of July Fireworks Display. This safety zone is... Safety Zone; Jameson Beach 4th of July Fireworks Display. (a) Location. This temporary safety zone is...

Lake level and climate records of the last 90 ka from the Northern Basin of Lake Van, eastern Turkey

NASA Astrophysics Data System (ADS)

Çağatay, M. N.; Öğretmen, N.; Damcı, E.; Stockhecke, M.; Sancar, Ü.; Eriş, K. K.; Özeren, S.

2014-11-01

Sedimentary, geochemical and mineralogical analyses of the ICDP cores recovered from the Northern Basin (NB) of Lake Van provide evidence of lake level and climatic changes related to orbital and North Atlantic climate system over the last 90 ka. High lake levels are generally observed during the interglacial and interstadial periods, which are marked by deposition of varved sediments with high total organic carbon (TOC), total inorganic carbon (TIC), low detrital influx (high Ca/F) and high δ18O and δ13C values of authigenic carbonate. During the glacial and stadial periods of 71-58 ka BP (Marine Isotope Stage 4, MIS4) and end of last glaciation-deglaciation (30-14.5 ka BP; MIS3) relatively low lake levels prevailed, and grey homogeneous to faintly laminated clayey silts were deposited at high sedimentation and low organic productivity rates. Millennial-scale variability of the proxies during 60-30 ka BP (MIS3 is correlated with the Dansgaard-Oeschger (D-O)) and Holocene abrupt climate events in the Atlantic. These events are characterized by laminated sediments, with high TOC, TIC, Ca/Fe, δ18O and δ13C values. The Lake Van NB records correlate well in the region with the climate records from the lakes Zeribar and Urmia in Iran and the Sofular Cave in NW Anatolia, but are in general in anti-phase to those from the Dead Sea Basin (Lake Lisan) in the Levant. The relatively higher δ18O values (0 to -0.4‰) for the interglacial and interstadial periods in the Lake Van NB section are due to the higher temperature and seasonality of precipitation and higher evaporation, whereas the lower values (-0.8 to -2‰) during the glacial and stadial periods are caused mainly by relative decrease in both temperature and seasonality of precipitation. The high δ18O values (up to 4.2‰) during the Younger Dryas, together with the presence of dolomite and low TOC contents, supports evaporative conditions and low lake level. A gradual decrease in the δ18O values from an

Holocene Record Of The Cuitzeo Lake, Michoacan, Central Mexico

NASA Astrophysics Data System (ADS)

Israde-Alcantar, I.; Bischoff, J.; Cram, S.; Ruiz-Fernandez, C.; Barron, J.; Lozano-Garcia, S.; Ortega-Guerrero, B.; Garduño-Monroy, V. H.

2007-05-01

A 205 cm-long core spanning the last ca.10,000 years was taken in the western basin of Lake Cuitzeo, located in the tectonic depressions of central Mexico. Age control for the core is provided by four AMS dates on organic sediment. The uppermost 30 cm of the core appears to be highly bioturbated according to Pb210 chronologies. A time plot of mass-accumulation rates of sediment (g/cm2/kyr) shows high rates from 10,000 to 6000 yrs BP, strikingly reduced mid-Holocene rates, and increasing rates post 1000 yrs (which could be due to introduction of European ranching and agriculture). Organic and inorganic carbon (TOC. TIC), diatoms, iron and titanium concentrations were analyzed and used to infer variations in the hydrological cycle and climatic conditions. The lower part of the core (ca.8000 C14 yr B.P.) is characterized by high percents of CaCO3 (more than 35 percent) which rapidly declines to values less than 20 percent after ca. 6000 C14 yr B.P., likely reflecting reduced summer precipitation due to decline summer insolation. Coincident with this decline in percents CaCO3 there is a decline greater that two-fold sediment accumulation rates and an increase in percents TOC. Two peaks TOC are recorded at 909 and 6744 C14 yr B.P. suggesting increased precipitation. The TOC peak at 909 C14 yr B.P. may be associated with increased precipitation during the Medieval Warm Period. The middle Holocene TOC peak at 6744 C14 yr B.P. coincides with a period of increased precipitation in the Cariaco Basin of Venezuela. These changes in precipitation are similar to those recorded in lake records from Guatemala and the marine record of the Cariaco Basin and can be explained by shifts in the mean latitude of the Atlantic Intertropical Convergence Zone (ITCZ). The upper 100 cm of the core was studied at 1 cm intervals for metals (Al, Fe, Ti, Pb, etc.) using ICPMS geochemistry. These metals show strong cycles throughout the studied interval which may reflect wet-dry cycles. A two fold

Morphology, volcanism, and mass wasting in Crater Lake, Oregon

USGS Publications Warehouse

Bacon, C.R.; Gardner, J.V.; Mayer, L.A.; Buktenica, M.W.; Dartnell, P.; Ramsey, D.W.; Robinson, J.E.

2002-01-01

Crater Lake was surveyed nearly to its shoreline by high-resolution multibeam echo sounding in order to define its geologic history and provide an accurate base map for research and monitoring surveys. The bathymetry and acoustic backscatter reveal the character of landforms and lead to a chronology for the concurrent filling of the lake and volcanism within the ca. 7700 calibrated yr B.P. caldera. The andesitic Wizard Island and central-plattform volcanoes are composed of sequences of lava deltas that record former lake levels and demonstrate simultaneous activity at the two vents. Wizard Island eruptions ceased when the lake was ~80 m lower than at present. Lava streams from prominent channels on the surface of the central platform descended to feed extensive subaqueous flow fields on the caldera floor. The Wizard Island and central-platform volcanoes, andesitic Merriam Cone, and a newly discovered probable lava flow on the eastern floor of the lake apparently date from within a few hundred years of caldera collapse, whereas a small rhydacite dome was emplaced on the flank of Wizard Island at ca. 4800 cal. yr B.P. Bedrock outcrops on the submerged caldera walls are shown in detail and, in some cases, can be correlated with exposed geologic units of Mount Mazama. Fragmental debris making up the walls elsewhere consists of narrow talus cones forming a dendritic pattern that leads to fewer, wider ridges downslope. Hummocky topography and scattered blocks up to ~280 m long below many of the embayments in the caldera wall mark debris-avalanche deposits that probably formed in single events and commonly are affected by secondary failures. The flat-floored, deep basins contain relatively fine-grained sediment transported from the debris aprons by sheet-flow turbidity currents. Crater Lake apparently filled rapidly (ca. 400-750 yr) until reaching a permeable layer above glaciated lava identified by the new survey in the northeast caldera wall at ~1845 m elevation

Mn/Ca intra- and inter-test variability in the benthic foraminifer Ammonia tepida

NASA Astrophysics Data System (ADS)

Petersen, Jassin; Barras, Christine; Bézos, Antoine; La, Carole; de Nooijer, Lennart J.; Meysman, Filip J. R.; Mouret, Aurélia; Slomp, Caroline P.; Jorissen, Frans J.

2018-01-01

The adaptation of some benthic foraminiferal species to low-oxygen conditions provides the prospect of using the chemical composition of their tests as proxies for bottom water oxygenation. Manganese may be particularly suitable as such a geochemical proxy because this redox element is soluble in reduced form (Mn2+) and hence can be incorporated into benthic foraminiferal tests under low-oxygen conditions. Therefore, intra- and inter-test differences in foraminiferal Mn/Ca ratios may hold important information about short-term variability in pore water Mn2+ concentrations and sediment redox conditions. Here, we studied Mn/Ca intra- and inter-test variability in living individuals of the shallow infaunal foraminifer Ammonia tepida sampled in Lake Grevelingen (the Netherlands) in three different months of 2012. The deeper parts of this lake are characterized by seasonal hypoxia/anoxia with associated shifts in microbial activity and sediment geochemistry, leading to seasonal Mn2+ accumulation in the pore water. Earlier laboratory experiments with similar seawater Mn2+ concentrations as encountered in the pore waters of Lake Grevelingen suggest that intra-test variability due to ontogenetic trends (i.e. size-related effects) and/or other vital effects occurring during calcification in A. tepida (11-25 % relative SD, RSD) is responsible for part of the observed variability in Mn/Ca. Our present results show that the seasonally highly dynamic environmental conditions in the study area lead to a strongly increased Mn/Ca intra- and inter-test variability (average of 45 % RSD). Within single specimens, both increasing and decreasing trends in Mn/Ca ratios with size are observed. Our results suggest that the variability in successive single-chamber Mn/Ca ratios reflects the temporal variability in pore water Mn2+. Additionally, active or passive migration of the foraminifera in the surface sediment may explain part of the observed Mn/Ca variability.

The Stream-Catchment (StreamCat) and Lake-Catchment ...

EPA Pesticide Factsheets

Background/Question/MethodsLake and stream conditions respond to both natural and human-related landscape features. Characterizing these features within contributing areas (i.e., delineated watersheds) of streams and lakes could improve our understanding of how biological conditions vary spatially and improve the use, management, and restoration of these aquatic resources. However, the specialized geospatial techniques required to define and characterize stream and lake watersheds has limited their widespread use in both scientific and management efforts at large spatial scales. We developed the StreamCat and LakeCat Datasets to model, predict, and map the probable biological conditions of streams and lakes across the conterminous US (CONUS). Both StreamCat and LakeCat contain watershed-level characterizations of several hundred natural (e.g., soils, geology, climate, and land cover) and anthropogenic (e.g., urbanization, agriculture, mining, and forest management) landscape features for ca. 2.6 million stream segments and 376,000 lakes across the CONUS, respectively. These datasets can be paired with field samples to provide independent variables for modeling and other analyses. We paired 1,380 stream and 1,073 lake samples from the USEPAs National Aquatic Resource Surveys with StreamCat and LakeCat and used random forest (RF) to model and then map an invertebrate condition index and chlorophyll a concentration, respectively. Results/ConclusionsThe invertebrate

75 FR 5114 - Desert National Wildlife Refuge Complex, Clark, Lincoln, and Nye Counties, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-01

... DEPARTMENT OF THE INTERIOR Fish and Wildlife Service [FWS-R8-R-2009-N222; 80230-1265-0000-S3] Desert National Wildlife Refuge Complex, Clark, Lincoln, and Nye Counties, NV AGENCY: Fish and Wildlife.... The Wildlife Refuge is located on 116 acres in northeastern Clark County. Due to its small size...

75 FR 29658 - Safety Zone; America's Discount Tire 50th Anniversary, Fireworks Display, South Lake Tahoe, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-27

... participants and spectators from the dangers associated with the pyrotechnics. Unauthorized persons or vessels... process before the event occurs. Because of the dangers posed by the pyrotechnics used in these fireworks... fireworks launch site during loading of the pyrotechnics, and during the fireworks displays. This restricted...

What can we learn from the Wells, NV earthquake sequence about seismic hazard in the intermountain west?

USGS Publications Warehouse

Petersen, M.D.; Pankow, K.L.; Biasi, G.P.; Meremonte, M.

2008-01-01

The February 21, 2008 Wells, NV earthquake (M 6) was felt throughout eastern Nevada, southern Idaho, and western Utah. The town of Wells sustained significant damage to unreinforced masonry buildings. The earthquake occurred in a region of low seismic hazard with little seismicity, low geodetic strain rates, and few mapped faults. The peak horizontal ground acceleration predicted by the USGS National Seismic Hazard Maps is about 0.2 g at 2% probability of exceedance in 50 years, with the contributions coming mostly from the Ruby Mountain fault and background seismicity (M5-7.0). The hazard model predicts that the probability of occurrence of an M>6 event within 50 km of Wells is about 15% in 100 years. Although the earthquake was inside the USArray Transportable Array network, the nearest on-scale recordings of ground motions from the mainshock were too distant to estimate accelerations in town. The University of Nevada Reno, the University of Utah, and the U.S. Geological Survey deployed portable instruments to capture the ground motions from aftershocks of this rare normal-faulting event. Shaking from a M 4.7 aftershock recorded on portable instruments at distances less than 10 km exceeded 0.3 g, and sustained accelerations above 0.1 g lasted for about 5 seconds. For a magnitude 5 earthquake at 10 km distance the NGA equations predict median peak ground accelerations about 0.1 g. Ground motions from normal faulting earthquakes are poorly represented in the ground motion prediction equations. We compare portable and Transportable Array ground-motion recordings with prediction equations. Advanced National Seismic System stations in Utah recorded ground motions 250 km from the mainshock of about 2% g. The maximum ground motion recorded in Salt Lake City was in the center of the basin. We analyze the spatial variability of ground motions (rock vs. soil) and the influence of the Salt Lake Basin in modifying the ground motions. We then compare this data with the

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.

Accelerated aggregation of donor nitrogen in diamond containing NV centers

NASA Astrophysics Data System (ADS)

Lobanov, Sergey; Vins, Victor; Yelisseev, Alexander; Afonin, Dmitry; Blinkov, Alexander; Maximov, Yuriy

2010-05-01

The aggregation of donor nitrogen (C centers) into nitrogen pairs (A centers) is considered to be a second-order chemical reaction and the kinetics of this reaction can be written as follows: Kt = 1-- -1- Ct C0 where K is the aggregation rate constant that depends exponentially on temperature and activation energy K = Aexp (- Ea-kT ) and C0 and CT are C center concentrations before and after the aggregation. The activation energy Ea in natural diamonds is equal to 5±0.3 eV. However, it was shown by Vins (2004) that Ea varied in synthetic diamonds depending on Ni concentration from 3 to 6 eV; and in synthetic diamonds containing cobalt the activation energy exceeded 4 eV. The aggregation rate of C centers also increased dramatically in diamonds irradiated with high-energy electrons (Collins, 1980). An HPHT diamond single crystal grown in the Fe-Co-C system using the TGG method was studied. The initial C center concentration determined from the intensity of the 1130 cm-1 IR absorption band was equal to 118 ppm. In order to determine the influence of NV centers on the activation energy of aggregation, the crystal was at first irradiated with high-energy electrons (3MeV, 2×1018cm-2) and annealed in a quartz ampoule in vacuum (8000C, 2 hrs). This led to the formation of over 5 ppm of NV centers. After that the sample was annealed at high temperatures in the argon flow (15300C, 30 minutes). The IR absorption spectra revealed an

Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design, volume 2

NASA Technical Reports Server (NTRS)

Soderquist, Joseph R. (Compiler); Neri, Lawrence M. (Compiler); Bohon, Herman L. (Compiler)

1992-01-01

This publication contains the proceedings of the Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design held at Lake Tahoe, Nevada, during 4-7 Nov. 1991. Presentations were made in the following areas of composite structural design: perspectives in composites, design methodology, design applications, design criteria, supporting technology, damage tolerance, and manufacturing.

Predicting susceptibility of white fir during a drought-associated outbreak of the fir engraver, Scolytus centralis, in California

Treesearch

G.T. Ferrell; W.J. Otrosina; C.J. DeMars

1994-01-01

Phenotypic traits were compared with a vigor (growth efficiency) index for accuracy in predicting susceptibility of white fir, Abies concolor (Gord. & Glend.) Lindl., during a drought-associated outbreak of the fir engraver, Scolytus centralis LeC., in the central Sierra Nevada at Lake Tahoe, California.Predictor variables were estimated for 633 firs in six forest...

Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design, volume 3

NASA Technical Reports Server (NTRS)

Soderquist, Joseph R. (Compiler); Neri, Lawrence M. (Compiler); Bohon, Herman L. (Compiler)

1992-01-01

This publication contains the proceedings of the Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design held at Lake Tahoe, Nevada, during 4-7 Nov. 1991. Presentations were made in the following areas of composite structural design: perspectives in composites, design methodology, design applications, design criteria, supporting technology, damage tolerance, and manufacturing.

Influence of permafrost on lake terraces of Lake Heihai (NE Tibetan Plateau)

NASA Astrophysics Data System (ADS)

Lockot, Gregori; Hartmann, Kai; Wünnemann, Bernd

2013-04-01

The Tibetan Plateau (TP) is one of the key regions for climatic global change. Besides the poles the TP is the third highest storage of frozen water in glaciers. Here global warming is three times higher than in the rest of the world. Additionally the TP provides water for billions of people and influences the moisture availability from the Indian and East Asian monsoon systems. During the Holocene extent and intensity of the monsoonal systems changed. Hence, in the last decades, a lot of work was done to reconstruct timing and frequency of monsoonal moisture, to understand the past and give a better forecast for the future. Comparative workings often show very heterogeneous patterns of timing and frequency of the Holocene precipitation and temperature maximum, emphasizing the local importance of catchment dynamics. In this study we present first results of lake Heihai (36°N, 93°15'E, 4500m a.s.l.), situated at the north-eastern border of the TP. The lake is surrounded by a broad band of near-shore lake sediments, attesting a larger lake extent in the past. These sediments were uplifted by permafrost, reaching nowadays heights ca. +8 meters above present lake level. Due to the uplift one of the main inflows was blocked and the whole hydrology of the catchment changed. To quantify the uplift of permafrost Hot Spot Analysis were accomplished at a DEM of the near-shore area. As a result regions of high permafrost uplift and those which mirror the original height of lake ground were revealed. The most obvious uplift took place in the northern and western part of the lake, where the four uplift centers are located. In contrast the southern and eastern areas show a rather degraded pattern (probably by fluvial erosion, thermokarst, etc.). The ancient lake bottom, without permafrost uplift was estimated to be 4-6 meters above the modern lake level. For a better understanding of permafrost interaction inside the terrace bodies a 5m sediment profile was sampled and

Development of JSTAMP-Works/NV and HYSTAMP for Multipurpose Multistage Sheet Metal Forming Simulation

NASA Astrophysics Data System (ADS)

Umezu, Yasuyoshi; Watanabe, Yuko; Ma, Ninshu

2005-08-01

Since 1996, Japan Research Institute Limited (JRI) has been providing a sheet metal forming simulation system called JSTAMP-Works packaged the FEM solvers of LS-DYNA and JOH/NIKE, which might be the first multistage system at that time and has been enjoying good reputation among users in Japan. To match the recent needs, "faster, more accurate and easier", of process designers and CAE engineers, a new metal forming simulation system JSTAMP-Works/NV is developed. The JSTAMP-Works/NV packaged the automatic healing function of CAD and had much more new capabilities such as prediction of 3D trimming lines for flanging or hemming, remote control of solver execution for multi-stage forming processes and shape evaluation between FEM and CAD. On the other way, a multi-stage multi-purpose inverse FEM solver HYSTAMP is developed and will be soon put into market, which is approved to be very fast, quite accurate and robust. Lastly, authors will give some application examples of user defined ductile damage subroutine in LS-DYNA for the estimation of material failure and springback in metal forming simulation.

Human Impact on Biogeochemical Cycles and Deposition Dynamics in Karstic Lakes: El Tobar Lake Record (Central Iberian Range, Spain)

NASA Astrophysics Data System (ADS)

Barreiro-Lostres, F.; Moreno-Caballud, A.; Giralt, S.; Hillman, A. L.; Brown, E. T.; Abbott, M. B.; Valero-Garces, B. L.

2014-12-01

Karstic lakes in the Iberian Range (Central Spain) provide a unique opportunity to test the human impact in the watersheds and the aquatic environments during historical times. We reconstruct the depositional evolution and the changes in biogeochemical cycles of El Tobar karstic lake, evaluating the response and the resilience of this Mediterranean ecosystem to both anthropogenic impacts and climate forcing during the last 1000 years. Lake El Tobar (40°32'N, 3°56'W; 1200 m a.s.l.; see Figure), 16 ha surface area, 20 m max. depth and permanent meromictic conditions, has a relatively large watershed (1080 ha). Five 8 m long sediment cores and short gravity cores where recovered, imaged, logged with a Geotek, described and sampled for geochemical analyses (elemental TOC, TIC, TN, TS), XRF scanner and ICP-MS, and dated (137Cs and 10 14C assays). The record is a combination of: i) laminated dark silts with terrestrial remains and diatoms and ii) massive to banded light silts (mm to cm -thick layers) interpreted as flood deposits. Sediments, TOC, and Br/Ti and Sr/Ca ratios identify four periods of increased sediment delivery occurred about 1500, 1800, 1850 and 1900 AD, coinciding with large land uses changes of regional relevance such as land clearing and increased population. Two main hydrological changes are clearly recorded in El Tobar sequence. The first one, marked by a sharp decrease in Mg, Ca and Si concentrations, took place about 1200 AD, and during a period of increasing lake level, which shifted from shallower to deeper facies and from carbonatic to clastic and organic-rich deposition. This change was likely related to increased water availability synchronous to the transition from the Medieval Climate Anomaly to the Little Ice Age. The second one was a canal construction in 1967 AD when a nearby reservoir provided fresh water influx to the lake, and resulted in stronger meromictic conditions in the system after canal construction, which is marked by lower

Recolonization and possible recovery of burrowing mayflies (Ephemeroptera: Ephemeridae: Hexagenia spp.) in Lake Erie of the Laurentian Great Lakes

USGS Publications Warehouse

Schloesser, Don W.; Krieger, Kenneth A.; Ciborowski, Jan J.H.; Corkum, Lynda D.

2000-01-01

Burrowing mayflies of the genus Hexagenia spp. were widely distributed (ca. 80% of sites) and abundant (ca. 160 nymphs/m2) in the western basin of Lake Erie of the Laurentian Great Lakes in 1929–1930, prior to a period of anoxia in the mid 1950s. Nymphs were absent or rare in the basin between 1961 and 1973–1975. In 1979–1991, nymphs were infrequently found (13–46% of sites) in low abundance (3–40 nymphs/m2) near shore (<7.5 km from shore), but were absent or rare offshore (0–7% of sites at 0–1 nymphs/m2). Increased abundance occurred offshore between 1991 (0% of sites) and 1993 (52% of sites at 7/m2). Annual sampling, beginning in 1995, indicates that nymphs increased in both nearshore and offshore waters. By 1997, nymphs were found throughout the lake (88% of sites) at a mean density 40-fold greater (392/m2) than that observed in 1993 (11/m2). In 1998, the distribution of nymphs remained the same as 1997 (88% of sites) but density declined 3-fold (392 to 134/m2). These data indicate that mayflies have recolonized sediments of western Lake Erie and that their abundance may be similar to levels observed before their disappearance in the mid 1950s. However, prior to the mid 1950s, densities were greater in offshore than nearshore waters, but between 1979 and 1998 greater densities occurred near shore than offshore. In addition, there were two areas in the 1990s where low densities consistently occurred. Therefore, recovery of nymphs in western Lake Erie may not have been complete in 1998. At present we do not know the cause for the sudden recolonization of nymphs in large portions of western Lake Erie. Undoubtedly, pollution-abatement programs contributed to improved conditions that would have ultimately led to mayfly recovery in the future. However, the explosive growth of the exotic zebra mussel, Dreissena polymorpha, undoubtedly diverted plankton foods to bottom substrates which could have increased the speed at which Hexagenia spp. nymphs

29. BETHLEHEM SHIPBUILDING CORP, LTD. UNION PLANT, SAN FRANCISCO, CA. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

29. BETHLEHEM SHIPBUILDING CORP, LTD. UNION PLANT, SAN FRANCISCO, CA. INBOARD PROFILE, SHEET NUMBER H-5314-11-10. Drawn by A.E. Wilson, undated. - San Mateo Ferry, South end of Lake Union, Seattle, King County, WA

30. BETHLEHEM SHIPBUILDING CORP, LTD. UNION PLANT, SAN FRANCISCO, CA. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

30. BETHLEHEM SHIPBUILDING CORP, LTD. UNION PLANT, SAN FRANCISCO, CA. MIDSHIP SECTION, SHEET NUMBER H-5314-11-2. Drawn by H.A. Lennon, undated. - San Mateo Ferry, South end of Lake Union, Seattle, King County, WA

77 FR 14000 - Foreign-Trade Zone 126-Reno, NV; Application for Temporary/Interim Manufacturing Authority...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-08

..., NV; Application for Temporary/ Interim Manufacturing Authority, Brightpoint North America L.P. (Cell... to produce cell phone kits (HTSUS 8517.12, 8517.69, duty free). Foreign components that would be used... customs entry procedures that apply to cell phone kits (duty free) for the foreign inputs noted above. In...

Endogenic carbonate sedimentation in Bear Lake, Utah and Idaho, over the last two glacial-interglacial cycles

USGS Publications Warehouse

Dean, W.E.

2009-01-01

Sediments deposited over the past 220,000 years in Bear Lake, Utah and Idaho, are predominantly calcareous silty clay, with calcite as the dominant carbonate mineral. The abundance of siliciclastic sediment indicates that the Bear River usually was connected to Bear Lake. However, three marl intervals containing more than 50% CaCO3 were deposited during the Holocene and the last two interglacial intervals, equivalent to marine oxygen isotope stages (MIS) 5 and 7, indicating times when the Bear River was not connected to the lake. Aragonite is the dominant mineral in two of these three high-carbonate intervals. The high-carbonate, aragonitic intervals coincide with warm interglacial continental climates and warm Pacific sea-surface temperatures. Aragonite also is the dominant mineral in a carbonate-cemented microbialite mound that formed in the southwestern part of the lake over the last several thousand years. The history of carbonate sedimentation in Bear Lake is documented through the study of isotopic ratios of oxygen, carbon, and strontium, organic carbon content, CaCO3 content, X-ray diffraction mineralogy, and HCl-leach chemistry on samples from sediment traps, gravity cores, piston cores, drill cores, and microbialites. Sediment-trap studies show that the carbonate mineral that precipitates in the surface waters of the lake today is high-Mg calcite. The lake began to precipitate high-Mg calcite sometime in the mid-twentieth century after the artificial diversion of Bear River into Bear Lake that began in 1911. This diversion drastically reduced the salinity and Mg2+:Ca2+ of the lake water and changed the primary carbonate precipitate from aragonite to high-Mg calcite. However, sediment-trap and core studies show that aragonite is the dominant mineral accumulating on the lake floor today, even though it is not precipitating in surface waters. The isotopic studies show that this aragonite is derived from reworking and redistribution of shallow-water sediment

Photonic Quantum Networks formed from NV(-) centers.

PubMed

Nemoto, Kae; Trupke, Michael; Devitt, Simon J; Scharfenberger, Burkhard; Buczak, Kathrin; Schmiedmayer, Jörg; Munro, William J

2016-05-24

In this article we present a simple repeater scheme based on the negatively-charged nitrogen vacancy centre in diamond. Each repeater node is built from modules comprising an optical cavity containing a single NV(-), with one nuclear spin from (15)N as quantum memory. The module uses only deterministic processes and interactions to achieve high fidelity operations (>99%), and modules are connected by optical fiber. In the repeater node architecture, the processes between modules by photons can be in principle deterministic, however current limitations on optical components lead the processes to be probabilistic but heralded. Our resource-modest repeater architecture contains two modules at each node, and the repeater nodes are then connected by entangled photon pairs. We discuss the performance of such a quantum repeater network with modest resources and then incorporate more resource-intense strategies step by step. Our architecture should allow large-scale quantum information networks with existing or near future technology.

76 FR 37034 - Proposed Modification of the Las Vegas, NV, Class B Airspace Area; Public Meetings; Correction

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-24

... Tuesday, August 23, 2011, in Henderson, NV. Also, the document contained the wrong phone number for the... number (2) in the ADDRESSES caption to read: ADDRESSES: (2) The meeting on Tuesday, August 23, 2011, will...

75 FR 6218 - New Melones Lake Area Resource Management Plan, Tuolumne and Calaveras Counties, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-08

... DEPARTMENT OF THE INTERIOR Bureau of Reclamation New Melones Lake Area Resource Management Plan...) has made available for public review a Final RMP/EIS for the New Melones Lake Area. The Final RMP/EIS... Dan Holsapple, Acting New Melones Resource Manager, Bureau of Reclamation, at 209-536- 9094...

Basic limnology of fifty-one lakes in Costa Rica.

PubMed

Haberyan, Kurt A; Horn, Sally P; Umaña, Gerardo

2003-03-01

We visited 51 lakes in Costa Rica as part of a broad-based survey to document their physical and chemical characteristics and how these relate to the mode of formation and geographical distribution of the lakes. The four oxbow lakes were low in elevation and tended to be turbid, high in conductivity and CO2, but low in dissolved O2; one of these, L. Gandoca, had a hypolimnion essentially composed of sea water. These were similar to the four wetland lakes, but the latter instead had low conductivities and pH, and turbidity was often due to tannins rather than suspended sediments. The thirteen artificial lakes formed a very heterogenous group, whose features varied depending on local factors. The thirteen lakes dammed by landslides, lava flows, or lahars occurred in areas with steep slopes, and were more likely to be stratified than most other types of lakes. The eight lakes that occupy volcanic craters tended to be deep, stratified, clear, and cool; two of these, L. Hule and L. Río Cuarto, appeared to be oligomictic (tending toward meromictic). The nine glacial lakes, all located above 3440 m elevation near Cerro Chirripó, were clear, cold, dilute, and are probably polymictic. Cluster analysis resulted in three significant groups of lakes. Cluster 1 included four calcium-rich lakes (average 48 mg l-1), Cluster 2 included fourteen lakes with more Si than Ca+2 and higher Cl- than the other clusters, and Cluster 3 included the remaining thirty-three lakes that were generally less concentrated. Each cluster included lakes of various origins located in different geographical regions; these data indicate that, apart from the high-altitude glacial lakes and lakes in the Miravalles area, similarity in lake chemistry is independent of lake distribution.

76 FR 28171 - Standard Instrument Approach Procedures, and Takeoff Minimums and Obstacle Departure Procedures...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-16

...-Clyde Ice Field, Takeoff Minimum and Obstacle DP, Amdt 1 Gladewater, TX, Gladewater Muni, Takeoff... Field, VOR/DME RWY 12, Amdt 4 Devil's Lake, ND, Devil's Lake Rgnl, ILS OR LOC/DME RWY 31, Amdt 2 Devil's Lake, ND, Devil's Lake Rgnl, RNAV (GPS) RWY 3, Amdt 1 Ely, NV, Ely Airport-Yelland Field, Takeoff...

Management strategies for sustainable western water

Treesearch

Scott Tyler; Sudeep Chandra; Gordon Grant

2017-01-01

With the effects of the dramatic western US drought still reverberating through the landscape, researchers gathered in advance of the 20th annual Lake Tahoe Summit to discuss western US water issues in the 21st century. This two-day workshop brought together ~40 researchers from universities and agencies (federal and state) to discuss the prospects that...

Modeling climate and fuel reduction impacts on mixed-conifer forest carbon stocks in the Sierra Nevada, California

Treesearch

Matthew D. Hurteau; Timothy A. Robards; Donald Stevens; David Saah; Malcolm North; George W. Koch

2014-01-01

Quantifying the impacts of changing climatic conditions on forest growth is integral to estimating future forest carbon balance. We used a growth-and-yield model, modified for climate sensitivity, to quantify the effects of altered climate on mixed-conifer forest growth in the Lake Tahoe Basin, California. Estimates of forest growth and live tree carbon stocks were...

75 FR 39705 - Notice of Temporary Closures on Public Lands in Northwestern Elko County, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-12

... DEPARTMENT OF THE INTERIOR Bureau of Land Management [LLNV0100000 L10600000.JJ0000 LXSS130F0000... Northwestern Elko County, NV AGENCY: Bureau of Land Management, Interior. ACTION: Notice of Temporary Closures... effect for the dates and times specified in this Notice on public lands administered by the Bureau of...

75 FR 19990 - Lake Casitas Resource Management Plan, Ventura County, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-16

... RMP would: (1) Ensure safe storage and timely delivery of high-quality water to users while enhancing..., California. The dam, which stores water for irrigation, municipal and industrial use within the Casitas Municipal Water District (CMWD), was completed in November 1958. Lake Casitas has a storage capacity of 254...

New insights on water level variability for Lake Turkana for the past 15 ka and at 150 ka from relict beaches

NASA Astrophysics Data System (ADS)

Forman, S. L.; Wright, D.

2015-12-01

Relict beaches adjacent to Lake Turkana provide a record of water level variability for the Late Quaternary. This study focused on deciphering the geomorphology, sedimentology, stratigraphy and 14C chronology of strand plain sequences in the Kalokol and Lothagam areas. Nine >30 m oscillations in water level were documented between ca. 15 and 4 ka. The earliest oscillation between ca. 14.5 and 13 ka is not well constrained with water level to at least 70 m above the present surface and subsequently fell to at least 50 m. Lake level increased to ~ 90 m between ca. 11.2 and 10.4 ka, post Younger Dryas cooling. Water level fell by >30 m by 10.2 ka, with another potential rise at ca. 8.5 ka to >70 m above current level. Lake level regressed by > 40 m at 8.2 ka coincident with cooling in the equatorial Eastern Atlantic Ocean. Two major >70 m lake level oscillations centered at 6.6 and 5.2 ka may reflect enhanced convection with warmer sea surface temperatures in the Western Indian Ocean. The end of the African Humid Period occurred from ca. 8.0 to 4.5 ka and was characterized by variable lake level (± > 40 m), rather than one monotonic fall in water level. This lake level variability reflects a complex response to variations in the extent and intensity of the East and West African Monsoons near geographic and topographic limits within the catchment of Lake Turkana. Also, for this closed lake basin excess and deficits in water input are amplified with a cascading lake effect in the East Rift Valley and through the Chew Bahir Basin. The final regression from a high stand of > 90 m began at. 5.2 ka and water level was below 20 m by 4.5 ka; and for the remainder of the Holocene. This sustained low stand is associated with weakening of the West African Monsoon, a shift of the mean position of Congo Air Boundary west of the Lake Turkana catchment and with meter-scale variability in lake level linked to Walker circulation across the Indian Ocean. A surprising observation is

Identification of amino acid residues in infectious hematopoietic necrosis virus (IHNV) NV protein necessary for viral replication and pathogenicity.

PubMed

Wu, Yang; Wang, Li; Guo, Tiantian; Jiang, Yanping; Qiao, Xinyuan; Sun, Li; Liu, Min; Tang, Lijie; Xu, Yigang; Li, Yijing

2018-05-18

Our previous studies demonstrated that the nonstructural NV protein of infectious hematopoietic necrosis virus (IHNV) was essential for efficient viral replication and pathogenicity, and that the amino acid residues 32 EGDL 35 of the NV protein were responsible for nuclear localization, and played important roles in suppressing IFN and inhibiting NF-κB activity. However, little is known about the influence of 32 EGDL 35 on IHNV replication and pathogenicity. In the present study, two recombinant IHNV strains with deletions of NV 32 EGDL 35 were generated and the effect on IHNV replication and pathogenicity was explored. Our results showed that both mutants stably replicated in Chinook salmon embryo cells for 15 consecutive passages, and had similar host-tropism as wild-type (wt) IHNV; however, titers of the mutants were lower than those of wt IHNV in CHSE-214 cells. Infection of rainbow trout showed wt IHNV produced 90% cumulative mortality, while the mutants produced 55% and 60% cumulative mortality, respectively. Histopathological evaluation showed that tissues from the liver, brain, kidney, and heart of fish infected with wt IHNV exhibited pathological changes, but significant lesions were found only in the liver and heart of fish infected with the recombinant viruses. In addition, the recombinant viruses induced higher expression levels of IFN1, Mx-1, and IL-6 compared with those induced by wt IHNV. These results indicated that the 32 EGDL 35 residues were essential for the efficient anti-IFN and NF-κB-inhibiting activity of NV. Our results provide a basis for understanding the roles of 32 EGDL 35 in IHNV replication and pathogenicity, and may prove beneficial in the prevention and control of IHNV infections of fish. Copyright © 2018. Published by Elsevier Ltd.

31. BETHLEHEM SHIPBUILDING CORP, LTD. UNION PLANT, SAN FRANCISCO, CA. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

31. BETHLEHEM SHIPBUILDING CORP, LTD. UNION PLANT, SAN FRANCISCO, CA. SALON DECK ARRANGEMENT, SHEET NUMBER 5314-11-84. Drawn by A.E. Wilson, dated 12-6-21. - San Mateo Ferry, South end of Lake Union, Seattle, King County, WA

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.

1. AERIAL VIEW OF WHITSETT (INTAKE) PUMP PLANT ON LAKE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. AERIAL VIEW OF WHITSETT (INTAKE) PUMP PLANT ON LAKE SHORE IN FOREGROUND; GENE IN BACKGROUND, LOOKING SOUTHWEST. - Whitsett Pump Plant, West side of Colorado River, north of Parker Dam, Parker Dam, San Bernardino County, CA

Late Quaternary palaeoenvironmental reconstruction from Lake Ohrid using stable isotopes

NASA Astrophysics Data System (ADS)

Lacey, Jack H.; Leng, Melanie J.; Francke, Alexander; Vogel, Hendrik; Zanchetta, Giovanni; Wagner, Bernd

2016-04-01

Lake Ohrid is a large, deep lake located on the Balkan Peninsula at the border between Macedonia and Albania, and is considered the oldest extant lake in Europe. An International Continental scientific Drilling Program (ICDP) deep drilling campaign was carried out in 2013 as part of the interdisciplinary Scientific Collaboration On Past Speciation Conditions in Lake Ohrid (SCOPSCO) project. Over 1500 m of sediment were recovered from six coring locations at the main target site in the central basin, where the maximum drill depth reached 569 m below the lake floor. Initial results indicate continuous lacustrine conditions over the past >1.2 Ma (Wagner et al., 2014). Here, we present oxygen and carbon isotope data (δ18O and δ13C) from carbonate from the upper 248 m of the SCOPSCO succession, which covers the last 640 ka, spanning marine isotope stages 15-1, according to an age model based on tephra and orbital tuning (Francke et al., 2015). Modern monitoring data show Lake Ohrid to be an evaporative system, where variations in δ18O of endogenic carbonate are primarily a function of changes in water balance, and δ13C largely reflects fluctuations in the amount of soil-derived CO2 and organic matter recycling. Our results indicate a trend from wetter to drier conditions through the Holocene, which is consistent with regional and hemispheric processes related to changes in insolation and progressive aridification. Over the last 640 ka, relatively stable climate conditions are inferred before ca. 450 ka, a transition to a wetter climate between ca. 400-250 ka, and a trend to drier climate after ca. 250 ka. Higher frequency, multi-millennial-scale oscillations observed during warm stages are most likely associated with regional climate change as a function of orbital forcing. This record is one of the most extensive and highly-resolved continental isotope records available, and emphasises the potential of Lake Ohrid as a valuable archive of long-term palaeoclimate and

Sources of methylmercury to a wetland-dominated lake in northern Wisconsin.

PubMed

Watras, C J; Morrison, K A; Kent, A; Price, N; Regnell, O; Eckley, C; Hintelmann, H; Hubacher, T

2005-07-01

Several lines of evidence suggest that wetlands may be a major source of methylmercury (MeHg) to receiving waters, perhaps explaining the strong correlation between concentrations of waterborne MeHg and dissolved organic carbon (DOC) in regions such as northern Wisconsin. We evaluated the relative importance of wetland export in the MeHg budget of a wetland-dominated lake in northern Wisconsin using mass balance. Channelized runoff from a large headwater wetland was the major source of water and total mercury (HgT) to the lake during the study period. The wetland also exported MeHg in high concentrations (0.2-0.8 ng L(-1)), resulting in an export rate similar to those reported for other northern wetlands (ca. 0.3 microg MeHg m(-2) y(-1)). Yet, based on intensive sampling during 2002, the mass of MeHg that accumulated in the lake during summer was an order of magnitude greater than the export of MeHg from the wetland to the lake. Hence, a large in-lake source of MeHg is inferred from the mass balance. Most of the accumulated MeHg built-up in anoxic hypolimnetic waters; and the build-up was roughly balanced by losses of inorganic Hg (Hg(II)) implying a chemical transformation within the anoxic water column. An abundance of sulfate-reducing bacteria (SRB) in hypolimnetic waters, established by DNA analysis of the pelagic microbial community, along with a previous report documenting high methylation rates in the hypolimnion of this lake (ca. 10% d(-1)), suggest that this transformation was microbially mediated. These findings indicate that the direct effect of wetland runoff may be outweighed by indirect effects on the lacustrine MeHg cycle, enhancing the load of Hg(II), the activity of SRB, and the retention of MeHg, especially in northern lakes with flushing times longer than six months.

Late Holocene lake-level variation in southeastern Lake Superior: Tahquamenon Bay, Michigan

USGS Publications Warehouse

Johnston, John W.; Baedke, Steve J.; Booth, Robert K.; Thompson, Todd A.; Wilcox, Douglas A.

2004-01-01

Internal architecture and ages of 71 beach ridges in the Tahquamenon Bay embayment along the southeastern shore of Lake Superior on the Upper Peninsula of Michigan were studied to generate a late Holocene relative lake-level curve. Establishing a long-term framework is important to examine the context of historic events and help predict potential future changes critical for effective water resource management. Ridges in the embayment formed between about 4,200 and 2,100 calendar years before 1950 (cal. yrs. B.P.) and were created and preserved every 28 A? 4.8 years on average. Groups of three to six beach ridges coupled with inflections in the lake-level curve indicate a history of lake levels fluctuations and outlet changes. A rapid lake-level drop (approximately 4 m) from about 4,100 to 3,800 cal. yrs. B.P. was associated with a fall from the Nipissing II high-water-level phase. A change from a gradual fall to a slight rise was associated with an outlet change from Port Huron, Michigan/Sarnia, Ontario to Sault Ste. Marie, Michigan/Ontario. A complete outlet change occurred after the Algoma high-water-level phase (ca. 2,400 cal. yrs. B.P.). Preliminary rates of vertical ground movement calculated from the strandplain are much greater than rates calculated from historical and geologic data. High rates of vertical ground movement could have caused tectonism in the Whitefish Bay area, modifying the strandplain during the past 2,400 years. A tectonic event at or near the Sault outlet also may have been a factor in the outlet change from Port Huron/Sarnia to Sault Ste. Marie.

32. BETHLEHEM SHIPBUILDING CORP, LTD. UNION PLANT, SAN FRANCISCO, CA. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

32. BETHLEHEM SHIPBUILDING CORP, LTD. UNION PLANT, SAN FRANCISCO, CA. MAIN DECK ARRANGEMENT, SHEET NUMBER H-5314-11-8B. Drawn by A.E. Wilson, dated 12-7-21. - San Mateo Ferry, South end of Lake Union, Seattle, King County, WA

Towards NV-based magnetic sensing in the time domain

NASA Astrophysics Data System (ADS)

Urbach, Elana; Sumarac, Tamara; Lovchinsky, Igor; Landig, Renate; Sanchez-Yamagishi, Javier; Andersen, Trond; Park, Hongkun; Lukin, Mikhail

2017-04-01

The study of protein folding dynamics is an outstanding problem in the biological sciences. We show that nitrogen-vacancy (NV) centers in diamond can be used to dynamically sense the conformational states of individual proteins under ambient conditions. We present preliminary data on time-domain detection of electronic spin labels which were chemically attached to the proteins, as well as label-free detection of native hydrogen nuclear spins within the protein. In addition, we discuss work towards polarizing boron-11 spins in atomically-thin hexagonal boron nitride using Hartmann-Hahn double resonance, with the ultimate goal of studying many-body spin dynamics and performing quantum simulation. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. DGE1144152.

24. OLD TIOGA ROAD VIEW, NOW MAY LAKE ROAD , ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

24. OLD TIOGA ROAD VIEW, NOW MAY LAKE ROAD , AT SNOW FLAT. MOUNT HOFFMAN AT CENTER REAR. LOOKING NW. GIS: N-37 49 34.6 / W-119 29 58.2 - Tioga Road, Between Crane Flat & Tioga Pass, Yosemite Village, Mariposa County, CA

Occurrence, spatial distribution, sources, and risks of polychlorinated biphenyls and heavy metals in surface sediments from a large eutrophic Chinese lake (Lake Chaohu).

PubMed

He, Wei; Bai, Ze-Lin; Liu, Wen-Xiu; Kong, Xiang-Zhen; Yang, Bin; Yang, Chen; Jørgensen, Sven Erik; Xu, Fu-Liu

2016-06-01

Surface sediment from large and eutrophic Lake Chaohu was investigated to determine the occurrence, spatial distribution, sources, and risks of polychlorinated biphenyls (PCBs) and heavy metals in one of the five biggest freshwater lakes in China. Total concentration of PCBs (Σ34PCBs) in Lake Chaohu was 672 pg g(-1) dry weight (dw), with a range of 7 to 3999 pg g(-1) dw, which was lower than other water bodies worldwide. The majority of heavy metals were detected at all sampling locations, except for Sr, B, and In. Concentrations of Al, Fe, Ca, Mn, Sr, Co, Zn, Cd, Pb, and Hg were similar to that reported for other lakes globally. Concentrations of K, Mg, Na, Li, Ga, and Ag were greater than the average, whereas those of Cr, Ni, and Cu were lower. Cluster analysis (CA) and positive matrix factorization (PMF) yielded accordant results for the source apportionment of PCBs. The technical PCBs and microbial degradation accounted for 34.2 % and 65.8 % of total PCBs using PMF, and PMF revealed that natural and anthropogenic sources of heavy metals accounted for 38.1 % and 61.8 %, respectively. CA indicated that some toxic heavy metals (e.g., Cd, In, Tl, and Hg) were associated with Ca-Na-Mg minerals rather than Fe-Mn minerals. The uncorrelated results between organic matter revealed by pyrolysis technology and heavy metals might be caused by the existence of competitive adsorption between organic matter and minerals. PCBs and heavy metals were coupling discharge without organochlorine pesticides (OCPs), but with polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (PBDEs). No sediment sample exceeded the toxic threshold for dioxin-like PCBs (dl-PCBs) set at 20 pg toxicity equivalency quantity (TEQ) g(-1), (max dl-PCBs, 10.9 pg TEQ g(-1)). However, concentrations of Ag, Cd, and Hg were at levels of environmental concern. The sediment in the drinking water source area (DWSA) was threatened by heavy metals from other areas, and some

Limnology of selected lakes in Ohio, 1975

USGS Publications Warehouse

Tobin, Robert L.; Youger, John D.

1977-01-01

Water-quality reconnaissance by the U.S. Geological Survey and Ohio Environmental Protection Agency, to evaluate the status of Ohio's lakes and reservoirs was begun in 1975 with studies of 17 lakes. Spring and summer data collections for each lake included: profile measurements of temperature, dissolved oxygen, pH, and specific conductance; field and laboratory analyses of physical, biological, chemical organic characteristics; (nutrient), and concentrations of major and minor chemical constituents from composites of the water column; and physical and chemical data from major inflows.Light penetration (secchi disk) ranged from 9.4 feet (2.9 meters) in Lake Hope to 0.4 feet (0.1 meter) in Acton Lake. Seasonal thermal stratification or stability is shown for 10 lakes deeper than 15 feet (4.6 meters). Unstable or modified temperature profiles were observed in shallow lakes (depths less than 15 feet) or lakes controlled through subsurface release valves.Dissolved oxygen saturation ranged from 229 percent (20.8 milligrams per liter) in the epilimnion of Paint Creek Lake to zero in the bottom waters of all thermally stabilized lakes. Marked chemical and physical differences and nutrient uptake and recycling developed within different thermal strata. Anaerobic zones were frequently characterized by hydrogen sulfide and ammonia.Calcium was the dominant or codominant cation, and bicarbonate and(or) sulfate were the major anions in all lakes sampled. Only Hope and Vesuvius Lakes had soft water (hardness less than 61 milligrams per liter as CaCO3 ), and both lakes were further characterized by low pH (less than 7.0). Specific conductance ranged from 510 micromhos (Deer Creek and Salt Fork Lakes) to 128 micromhos (Lake Hope). Pesticide residues were detected in Acton Lake, and concentrations of one or more trace metals were at or above Ohio Environmental Protection Agency recommended limits in 11 lakes.Fecal coliform colony counts were below 400 colonies per 100 milliliters in

Interpreting the History of Lake Anoxia Using Iron and Sulfur Geochemistry

NASA Astrophysics Data System (ADS)

Ku, T.; Lozewski, J.; Ekdahl, E.; Teranes, J.

2004-05-01

Over the last thousand years, anthropogenic activities, such as land cultivation and atmospheric pollution, have increased the flux of growth-limiting nutrients to several North American lakes. The most common effect of this enhanced nutrient supply is a dramatic increase in the abundance of aquatic plants and algae. When these organisms die, the organic carbon in their remains falls through the water column and is oxidized by dissolved oxygen. Thus, eutrophic lakes are characterized by seasonally or permanently anoxic bottom waters because the rate of organic carbon oxidation exceeds the rate at which oxygen is replenished. The depletion of water column oxygen adversely affects lake ecosystems by decreasing water quality and by altering the community structure of fish and algae populations. In this study we examine the history of lake anoxia in two North American lakes, Half-Moon Lake in Michigan and Crawford Lake in Ontario. Sediment freeze cores and water column samples were taken from each site and both lakes contained well-preserved varved sediments. The sediments were analyzed for FeH (HCl-extractable iron), AVS (acid-volatile sulfur), CRS (chromium-reducible sulfur), d34S(CRS), CaCO3, CH2O, C/N, and d13C (CaCO3). Water samples were analyzed for pH, O2, cations, anions, and d34S(SO4). Today, Half-Moon Lake is seasonal anoxic while Crawford Lake has not overturned in the past ~15 years. Geochemical and biological data indicate that both lakes have experienced cultural eutrophication events in the 1800-1900s related to European-style agricultural practices. In addition, Crawford Lake experienced an earlier eutrophication episode around 1325 A.D. related to Iroquoian settlement of the area. Each eutrophication event showed an increase in the mass accumulation rate of pyritic sulfur, suggesting that sediments were exposed to longer durations of low-O2, H2S-rich waters during periods of cultural eutrophication. The geochemical parameter DOP (degree of pyritization

Local to regional scale industrial heavy metal pollution recorded in sediments of large freshwater lakes in central Europe (lakes Geneva and Lucerne) over the last centuries.

PubMed

Thevenon, Florian; Graham, Neil D; Chiaradia, Massimo; Arpagaus, Philippe; Wildi, Walter; Poté, John

2011-12-15

This research first focuses on the spatial and temporal patterns of heavy metals from contrasting environments (highly polluted to deepwater sites) of Lake Geneva. The mercury (Hg) and lead (Pb) records from two deepwater sites show that the heavy metal variations before the industrial period are primarily linked to natural weathering input of trace elements. By opposition, the discharge of industrial treated wastewaters into Vidy Bay of Lake Geneva during the second part of the 20th century, involved the sedimentation of highly metal-contaminated sediments in the area surrounding the WWTP outlet pipe discharge. Eventually, a new Pb isotope record of sediments from Lake Lucerne identifies the long-term increasing anthropogenic lead pollution after ca. 1500, probably due to the development of metallurgical activities during the High Middle Ages. These data furthermore allows to compare the recent anthropogenic sources of water pollution from three of the largest freshwater lakes of Western Europe (lakes Geneva, Lucerne, and Constance). High increases in Pb and Hg highlight the regional impact of industrial pollution after ca. 1750-1850, and the decrease of metal pollution in the 1980s due to the effects of remediation strategies such as the implementation of wastewater treatment plants (WWTPs). However, at all the studied sites, the recent metal concentrations remain higher than pre-industrial levels. Moreover, the local scale pollution data reveal two highly contaminated sites (>100 μg Pb/g dry weight sediment) by industrial activities, during the late-19th and early-20th centuries (Lake Lucerne) and during the second part of the 20th century (Vidy Bay of Lake Geneva). Overall, the regional scale pollution history inferred from the three large and deep perialpine lakes points out at the pollution of water systems by heavy metals during the last two centuries due to the discharge of industrial effluents. Copyright © 2011 Elsevier B.V. All rights reserved.

Application of the Gillette model for windblown dust at Owens Lake, CA

NASA Astrophysics Data System (ADS)

Ono, Duane

Windblown dust can have significant impacts on local air pollution levels, and in cases such as dust from Africa or Asia, can have global impacts on our environment. Models to estimate particulate matter emissions from windblown dust are generally based on the local wind speed, the threshold wind speed to initiate erosion, and the soil texture of a given surface. However, precipitation, soil crusting, and soil disturbance can dramatically change the threshold wind speed and erosion potential of a surface, making modeling difficult. A low-cost sampling and analysis method was developed to account for these surface changes in a wind erosion model. Windblown dust emissions measured as PM 10 (particulate matter less than a nominal 10 μm aerodynamic diameter) have been found to be generally proportional to sand flux (also known as saltation flux). In this study, a model was used to estimate sand flux using the relationship Q=AρG/g, where Q is horizontal sand flux, A is a surface erosion potential factor, ρ is air density, g is the gravitational constant, and G=∫ u*(u*2-u*t2)dt, where u* is friction velocity and u is the threshold friction velocity of the surface. The variable A in the model was derived by comparing the measured sand flux for a given period and area to G for the same period. Sand flux was monitored at Owens Lake, CA using low-cost Cox Sand Catchers (CSCs) for monthly measurements, and more expensive electronic sensors (Sensits) to measure hourly flux rates and u. Monitors were spaced 1 km apart at 114 sites, covering one clay and three sand-dominated soil areas. Good model results relied primarily on the erosion potential A, which could be determined from CSC measurements and wind speed data. Annual values for A were found to range from 1.3 to 3.5 in the three sand areas. The value of A was an order of magnitude lower (0.2) in the less erodible clay area. Previous studies showed similar values for A of 0.7 and 2.9 for a sandy site at Owens Lake, and

Responses of 20 lake-watersheds in the Adirondack region of New York to historical and potential future acidic deposition.

PubMed

Zhou, Qingtao; Driscoll, Charles T; Sullivan, Timothy J

2015-04-01