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At least 811 records · Page 45Linked to original sources

EAARL coastal topography–Northeast Barrier Islands 2007: First surface

These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the northeast coastal barrier islands in New York and New Jersey, acquired April 29-30 and May 15-16, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is routinely used to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

New York↗

EAARL coastal topography– Northeast barrier islands 2007: Bare earth

These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the northeast coastal barrier islands in New York and New Jersey, acquired April 29-30 and May 15-16, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is routinely used to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

New York↗

Simulation of the mobility of metal-EDTA complexes in groundwater: The influence of contaminant metals

Reactive transport simulations were conducted to model chemical reactions between metal−EDTA (ethylenediaminetetraacetic acid) complexes during transport in a mildly acidic quartz−sand aquifer. Simulations were compared with the results of small-scale tracer tests wherein nickel−, zinc−, and calcium−EDTA complexes and free EDTA were injected into three distinct chemical zones of a plume of sewage-contaminated groundwater. One zone had a large mass of adsorbed, sewage-derived zinc; one zone had a large mass of adsorbed manganese resulting from mildly reducing conditions created by the sewage plume; and one zone had significantly less adsorbed manganese and negligible zinc background. The chemical model assumed that the dissolution of iron(III) from metal−hydroxypolymer coatings on the aquifer sediments by the metal−EDTA complexes was kinetically restricted. All other reactions, including metal−EDTA complexation, zinc and manganese adsorption, and aluminum hydroxide dissolution were assumed to reach equilibrium on the time scale of transport; equilibrium constants were either taken from the literature or determined independently in the laboratory. A single iron(III) dissolution rate constant was used to fit the breakthrough curves observed in the zone with negligible zinc background. Simulation results agreed well with the experimental data in all three zones, which included temporal moments derived from breakthrough curves at different distances downgradient from the injections and spatial moments calculated from synoptic samplings conducted at different times. Results show that the tracer cloud was near equilibrium with respect to Fe in the sediment after 11 m of transport in the Zn-contaminated region but remained far from equilibrium in the other two zones. Sensitivity studies showed that the relative rate of iron(III) dissolution by the different metal−EDTA complexes was less important than the fact that these reactions are rate controlled. Results suggest that the published solubility for ferrihydrite reasonably approximates the Fe solubility of the hydroxypolymer coatings on the sediments. Aluminum may be somewhat more soluble than represented by the equilibrium constant for gibbsite, and its dissolution may be rate controlled when reacting with Ca−EDTA complexes.

Environmental Science & Technology↗

Bioenergy potential of the United States constrained by satellite observations of existing productivity

United States (U.S.) energy policy includes an expectation that bioenergy will be a substantial future energy source. In particular, the Energy Independence and Security Act of 2007 (EISA) aims to increase annual U.S. biofuel (secondary bioenergy) production by more than 3-fold, from 40 to 136 billion liters ethanol, which implies an even larger increase in biomass demand (primary energy), from roughly 2.9 to 7.4 EJ yr –1 . However, our understanding of many of the factors used to establish such energy targets is far from complete, introducing significgant uncertainty into the feasibility of current estimates of bioenergy potential. Here, we utilized satellite-derived net primary productivity (NPP) data—measured for every 1 km 2 of the 7.2 million km 2 of vegetated land in the conterminous U.S.—to estimate primary bioenergy potential (PBP). Our results indicate that PBP of the conterminous U.S. ranges from roughly 5.9 to 22.2 EJ yr –1 , depending on land use. The low end of this range represents the potential when harvesting residues only, while the high end would require an annual biomass harvest over an area more than three times current U.S. agricultural extent. While EISA energy targets are theoretically achievable, we show that meeting these targets utilizing current technology would require either an 80% displacement of current crop harvest or the conversion of 60% of rangeland productivity. Accordingly, realistically constrained estimates of bioenergy potential are critical for effective incorporation of bioenergy into the national energy portfolio.

Environmental Science & Technology↗

U.S. Geological Survey activities related to American Indians and Alaska Natives: Fiscal years 2007 and 2008

In the late 1800s, John Wesley Powell, the second director of the U.S. Geological Survey (USGS), followed his interest in the tribes of the Great Basin and Colorado Plateau and studied their cultures, languages, and surroundings. From that early time, the USGS has recognized the importance of Native knowledge and living in harmony with nature as complements to the USGS mission to better understand the Earth. Combining traditional ecological knowledge with empirical studies allows the USGS and Native American governments, organizations, and people to increase their mutual understanding and respect for this land. The USGS is the earth and natural science bureau within the U.S. Department of the Interior (DOI) and is not responsible for regulations or land management. Climate change is a major current issue affecting Native lives and traditions throughout the United States. Climate projections for the coming century indicate an increasing probability for more frequent and more severe droughts in the Southwest, including the Navajo Nation. Erosion has claimed Native homes in Alaska. Fish have become inedible due to diseases that turn their flesh mushy. Native people who rely on or who are culturally sustained by hunting, fishing, and using local plants are living with climate change now. The traditional knowledge of Native peoples enriches and confirms the work of USGS scientists. The results are truly synergistic-greater than the sum of their parts. Traditional ecological knowledge is respected and increasingly used in USGS studies-when the holders of that knowledge choose to share it. The USGS respects the rights of Native people to maintain their patrimony of traditional ecological knowledge. The USGS studies can help Tribes, Native organizations, and natural resource professionals manage Native lands and resources with the best available unbiased data and information that can be added to their traditional knowledge. Wise Native leaders have noted that traditional ecological knowledge includes the connections between Earth and her denizens. From this perspective, it is the connections among these ?relatives? that needs to be nurtured. This perspective on nature is finding new adherents among Natives and non-Natives as understanding of climate change and other environmental conditions deepens. Although this report uses the term ?resources,? the USGS, through its interdisciplinary research, acknowledges the interconnectedness of the Earth and the things that live upon it.

Circular↗

EAARL Topography-Vicksburg National Military Park 2007: First Surface

These remotely sensed, geographically referenced elevation measurements of Lidar-derived first-surface (FS) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Gulf Coast Network, Lafayette, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the Vicksburg National Military Park in Mississippi, acquired on September 12, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

Data Series↗

EAARL topography - Vicksburg National Military Park 2008: Bare earth

These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Gulf Coast Network, Lafayette, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the Vicksburg National Military Park in Mississippi, acquired on March 6, 2008. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

Mississippi↗

Contaminant gradients in trees: Directional tree coring reveals boundaries of soil and soil-gas contamination with potential applications in vapor intrusion assessment

Contaminated sites pose ecological and human-health risks through exposure to contaminated soil and groundwater. Whereas we can readily locate, monitor, and track contaminants in groundwater, it is harder to perform these tasks in the vadose zone. In this study, tree-core samples were collected at a Superfund site to determine if the sample-collection location around a particular tree could reveal the subsurface location, or direction, of soil and soil-gas contaminant plumes. Contaminant-centroid vectors were calculated from tree-core data to reveal contaminant distributions in directional tree samples at a higher resolution, and vectors were correlated with soil-gas characterization collected using conventional methods. Results clearly demonstrated that directional tree coring around tree trunks can indicate gradients in soil and soil-gas contaminant plumes, and the strength of the correlations were directly proportionate to the magnitude of tree-core concentration gradients (spearman’s coefficient of -0.61 and -0.55 in soil and tree-core gradients, respectively). Linear regression indicates agreement between the concentration-centroid vectors is significantly affected by in-planta and soil concentration gradients and when concentration centroids in soil are closer to trees. Given the existing link between soil-gas and vapor intrusion, this study also indicates that directional tree coring might be applicable in vapor intrusion assessment.

Missouri↗

The distribution, occurrence and environmental effect of mercury in Chinese coals

Mercury (Hg) is a toxic, persistent, and globally distributed pollutant due to its characteristic properties such as low melting and boiling points, conversion between chemical forms and participation in biological cycles. During combustion mercury in coal is almost totally emitted to the atmosphere. With a huge amount of coal consumed, coal combustion is one of the main anthropogenic sources of this element in the environment. In this study, Hg data of 1699 coal samples of China has been compiled, and the concentration, distribution, modes of occurrence, and the impact of Hg emissions on the environment are investigated. Most Chinese coals have Hg content in the range of 0.1 to 0.3??ppm, with an average of 0.19??ppm, which is slightly higher than the average Hg content of world coals and is close to that of the U.S. coals. The Hg content in coals varies in different coal basins, geological ages and coal ranks. The most likely mode of occurrences of Hg in high-sulfur and high Hg content coals is as solid solution in pyrite. But in low-sulfur coals, modes of occurrence of Hg are variable, and the organic-bound and sulfide-bound Hg may dominate. Silicate-bound Hg may be the main form in some coals because of magmatic intrusion. Mercury emissions during coal combustion have resulted in serious environmental contamination in China, particularly in the northeastern and southwestern China, where a high Hg content in the atmosphere occurs. ?? 2007 Elsevier B.V. All rights reserved.

Science of the Total Environment↗

EAARL topography - Natchez Trace Parkway 2007: First surface

These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Gulf Coast Network, Lafayette, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Natchez Trace Parkway in Mississippi, acquired on September 14, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

Data Series↗

Statistical analysis of the radon-222 potential of rocks in Virginia, U.S.A.

More than 3,200 indoor radon-222 (222Rn) measurements were made seasonally in an area of about 1,000 square kilometers of the Coastal Plain and Piedmont physiographic provinces in Virginia, U.S.A. Results of these measurements indicate that some geological units are associated, on the average, with twice as much indoor222Rn as other geological units, and that indoor222Rn varies seasonally. The Kruskal-Wallis test was used to test whether indoor222Rn concentrations for data gathered over the winter and summer seasons differ significantly by rock unit. The tests concluded that indoor222Rn concentrations for different rock units were not equal at the 5-percent significance level. The rocks associated with the highest median indoor222Rn concentration are specific rocks in the Mesozoic Culpeper basin, including shale and siltstone units with Jurassic diabase intrusives, and mica schists in the Piedmont physiographic province. The pre-Triassic Peters Creek Schist has the highest ranking in terms of indoor222Rn concentration. The rocks associated with the lowest indoor222Rn concentrations include coastal plain sediments, the Occoquan Granite, Falls Church Tonalite, Piney Branch Mafic and Ultramafic complex, and unnamed mafic and ultramafic inclusions, respectively. The rocks have been ranked according to observed222Rn concentration by transforming the average rank of indoor222Rn concentrations to z scores. ?? 1992 Springer-Verlag New York Inc.

Environmental Geology and Water Sciences↗

Environmental influences on speleothem growth in southwestern Oregon during the last 380, 000 years

The growth of carbonate formations in caves (speleothems) is sensitive to changes in environmental conditions at the surface (temperature, precipitation and vegetation) and can provide useful paleoclimatic and paleoenvironmental information. We use 73 230 Th dates from speleothems collected from a cave in southwestern Oregon (USA) to constrain speleothem growth for the past 380 000 years. Most speleothem growth occurred during interglacial periods, whereas little growth occurred during glacial intervals. To evaluate potential environmental controls on speleothem growth we use two new modeling approaches: i) a one-dimensional thermal advection–diffusion model to estimate cave temperatures during the last glacial cycle, and ii) a regional climate model simulation for the Last Glacial Maximum (21 000 years before present) that assesses a range of potential controls on speleothem growth under peak glacial conditions. The two models are mutually consistent in indicating that permafrost formation did not influence speleothem growth during glacial periods. Instead, the regional climate model simulation combined with proxy data suggest that the influence of the Laurentide and Cordilleran ice sheets on atmospheric circulation induced substantial changes in water balance in the Pacific Northwest and affected speleothem growth at our location. The overall drier conditions during glacial intervals and associated periods of frozen topsoil at times of maximum surface runoff likely induced drastic changes in cave recharge and limited speleothem growth. This mechanism could have affected speleothem growth in other mid-latitude caves without requiring the presence of permafrost.

Oregon↗

Effects of flow regime on metal concentrations and the attainment of water quality standards in a remediated stream reach, Butte, Montana

Low-flow synoptic sampling campaigns are often used as the primary tool to characterize watersheds affected by mining. Although such campaigns are an invaluable part of site characterization, investigations which focus solely on low-flow conditions may yield misleading results. The objective of this paper is to demonstrate this point and elucidate the mechanisms responsible for the release of metals during rainfall runoff. This objective is addressed using data from diel and synoptic sampling campaigns conducted over a two-day period. Low-flow synoptic sampling results indicate that concentrations of most constituents meet aquatic standards. This finding is in contrast to findings from a diel sampling campaign that captured dramatic increases in concentrations during rainfall runoff. Concentrations during the rising limb of the hydrograph were 2–23 times concentrations observed during synoptic sampling (most increases were >10-fold), remaining elevated during the receding limb of the hydrograph to produce a clockwise hysteresis loop. Hydrologic mechanisms responsible for the release of metals include increased transport due to resuspension of streambed solids, erosion of alluvial tailings, and overland flow. Rainfall also elevated the alluvial groundwater table and increased infiltration through the vadose zone, likely resulting in dissolution from alluvial tailings that were dry prior to the event.

Montana↗

Evidence of coupled carbon and iron cycling at a hydrocarbon-contaminated site from time lapse magnetic susceptibility

Conventional characterization and monitoring of hydrocarbon (HC) pollution is often expensive and time-consuming. Magnetic susceptibility (MS) has been proposed as an inexpensive, long-term monitoring proxy of the degradation of HC. We acquired repeated down hole MS logging data in boreholes at a HC-contaminated field research site in Bemidji, MN, USA. The MS data were analyzed in conjunction with redox conditions and iron availability within the source zone to better assess whether MS can serve as a proxy for monitoring HC contamination in unconsolidated sediments. The MS response at the site diminished during the sampling period, which was found to coincide with depletion of solid phase iron in the source zone. Previous geochemical observations and modeling at the site suggest that the most likely cause of the decrease in MS is the transformation of magnetite to siderite, coupled with the exhaustion of ferrihydrite. Although the temporal MS response at this site gives valuable field-scale evidence for changing conditions of iron cycling and stability of iron minerals it does not provide a simple proxy for long-term monitoring of biodegradation of hydrocarbons in the smear zone.

Minnesota↗

Evaluation of the factors controlling the time-dependent inactivation rate coefficients of bacteriophage MS2 and PRD1

Static and dynamic batch experiments were conducted to study the effects of temperature and the presence of sand on the inactivation of bacteriophage MS2 and PRD1. The experimental data suggested that the inactivation process can be satisfactorily represented by a pseudo-first-order expression with time-dependent rate coefficients. The time-dependent rate coefficients were used to determine pertinent thermodynamic properties required for the analysis of the molecular processes involved in the inactivation of each bacteriophage. A combination of high temperature and the presence of sand appears to produce the greatest disruption to the surrounding protein coat of MS2. However, the lower activation energies for PRD1 indicate a weaker dependence of the inactivation rate on temperature. Instead, the presence of air-liquid and air-solid interfaces appears to produce the greatest damage to specific viral components that are related to infection. These results indicate the importance of using thermodynamic parameters based on the time-dependent inactivation model to better predict the inactivation of viruses in groundwater. ?? 2006 American Chemical Society.

Environmental Science & Technology↗

Relations between introduced fish and environmental conditions at large geographic scales

Data collected from 20 major river basins between 1993 and 1995 as part of the US Geological Survey's (USGS) National Water-Quality Assessment (NAWQA) Program were analyzed to assess patterns in introduced and native fish species richness and abundance relative to watershed characteristics and stream physicochemistry. Sites (N = 157) were divided into three regions-northeast, southeast, and west- to account for major longitudinal differences in precipitation/runoff and latitudinal limits of glaciation that affect zoogeographic patterns in fish communities. Common carp (Cyprinus carpio) and largemouth bass (Micropterus salmoides) were the most frequently collected introduced fish species across all river basins combined. Based on the percentage of introduced fish species, the fish communities most altered by the presence of introduced fish occurred in the western and northeastern parts of the US. Native fish species richness was not an indicator of introduced fish species richness for any of the three regions. However, in the west, introduced fish species richness was an indicator of total fish species richness and the abundance of introduced fish was negatively related to native fish species richness. Some relations between introduced fish species and environmental conditions were common between regions. Increased introduced fish species richness was related to increased population density in the northeast and southeast; increased total nitrogen in the northeast and west; and increased total phosphorous and water temperature in the southeast and west. These results suggest that introduced fish species tend to be associated with disturbance at large geographic scales, though specific relations may vary regionally. ?? 2003 Elsevier Science Ltd. All rights reserved.

Ecological Indicators↗

EAARL topography: Jean Lafitte National Historical Park and Preserve 2006

These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) and bare earth (BE) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Gulf Coast Network, Lafayette, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the Jean Lafitte National Historical Park and Preserve in Louisiana, acquired on September 22, 2006. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

Louisiana↗

EAARL topography - George Washington Birthplace National Monument 2008

These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) and first surface (FS) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Northeast Coastal and Barrier Network, Kingston, RI; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the George Washington Birthplace National Monument in Virginia, acquired on March 26, 2008. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL) was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is routinely used to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

Virginia↗