Modeling and risk assessment for soil temperatures beneath prescribed forest fires

Treesearch

Haiganoush K. Preisler; Sally M. Haase; Stephen S. Sackett

2000-01-01

Prescribed fire is a management tool used by wildland resource management organizations in many ecosystems to reduce hazardous fuels and to achieve a host of other objectives. To study the effects of fire in naturally accumulating fuel conditions, the ambient soil temperature is monitored beneath prescribed burns. In this study we developed a stochastic model for...

Superfund record of decision (EPA Region 7): St. Louis Airport/HHS/Futura Coatings Co. , St. Louis County, MO, August 27, 1998

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

Not Available

1999-03-01

This document presents the selected remedial action for the cleanup of wastes related to Manhattan Engineering District/Atomic Energy Commission (MED/AEC) operations in accessible soils and ground water at the St. Louis Downtown Site (SLDS). The main components of the selected remedial action include: Excavation and off-site disposal of approximately 65,000 cubic meters (85,000 cubic yards) (in-situ) contaminated soil; and No remedial action is required for ground water beneath the site. Perimeter monitoring of the ground water in the Mississippi River alluvial aquifer, designated as the hydrostratigraphic B Unit, will be performed and the need for ground water remediation will bemore » evaluated as part of the periodic reviews performed for the site.« less

Mars Surface near Viking Lander 1 Footpad

NASA Technical Reports Server (NTRS)

2008-01-01

This image, which has been flipped horizontally, was taken by Viking Lander 1 on August 1, 1976, 12 sols after landing. Much like images that have returned from Phoenix, the soil beneath Viking 1 has been exposed due to exhaust from thruster engines during descent. This is visible to the right of the struts of Viking's surface-sampler arm housing, seen on the left.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

Differential effects of lichens, mosses and grasses on respiration and nitrogen mineralization in soils of the New Jersey Pinelands.

PubMed

Sedia, Ekaterina G; Ehrenfeld, Joan G

2005-06-01

In the New Jersey Pinelands, severely disturbed areas often do not undergo a rapid succession to forest; rather, a patchy cover of lichens, mosses and grasses persists for decades. We hypothesized that these plant covers affect soil microbial processes in different ways, and that these effects may alter the successional dynamics of the patches. We predicted that the moss and grass covers stimulate soil microbial activity, whereas lichens inhibit it, which may in turn inhibit succession. We collected soil cores from beneath each type of cover plus bare soil within two types of highly disturbed areas--sites subjected to hot wildfires, and areas mined for sand. Organic matter (OM) content, soil respiration and potential N mineralization were measured in the cores. Soils under mosses were similar to those under grasses; they accumulated more OM and produced more mineral N, predominantly in the form of ammonium, than either the bare soils or the soils beneath lichens. Mineralization under lichens, like that of the bare soils but unlike the soils beneath mosses or grasses, was dominated by net nitrification. These patterns were reproduced in experimentally transplanted moss and lichen mats. Mosses appear to create high-nutrient microsites via high rates of OM accumulation and production of ammonium, whereas lichens maintain low-nutrient patches similar to bare soil via low OM accumulation rates and production of mineral N predominantly in the mobile nitrate form. These differences in soil properties may explain the lack of vascular plant invasion in lichen mats, in contrast to the moss-dominated areas.

Tree seedlings respond to both light and soil nutrients in a Patagonian evergreen-deciduous forest.

PubMed

Promis, Alvaro; Allen, Robert B

2017-01-01

Seedlings of co-occurring species vary in their response to resource availability and this has implications for the conservation and management of forests. Differential shade-tolerance is thought to influence seedling performance in mixed Nothofagus betuloides-Nothofagus pumilio forests of Patagonia. However, these species also vary in their soil nutrient requirements. To determine the effects of light and soil nutrient resources on small seedlings we examined responses to an experimental reduction in canopy tree root competition through root trenching and restricting soil nutrient depletion through the addition of fertilizer. To understand the effect of light these treatments were undertaken in small canopy gaps and nearby beneath undisturbed canopy with lower light levels. Seedling diameter growth was greater for N. pumilio and height growth was greater for N. betuloides. Overall, diameter and height growth were greater in canopy gaps than beneath undisturbed canopy. Such growths were also greater with fertilizer and root trenching treatments, even beneath undisturbed canopy. Seedling survival was lower under such treatments, potentially reflecting thinning facilitated by resource induced growth. Finally, above-ground biomass did not vary among species although the less shade tolerant N. pumilio had higher below-ground biomass and root to shoot biomass ratio than the more shade tolerant N. betuloides. Above- and below-ground biomass were higher in canopy gaps so that the root to shoot biomass ratio was similar to that beneath undisturbed canopy. Above-ground biomass was also higher with fertilizer and root trenching treatments and that lowered the root to shoot biomass ratio. Restricting soil nutrient depletion allowed seedlings of both species to focus their responses above-ground. Our results support a view that soil nutrient resources, as well as the more commonly studied light resources, are important to seedlings of Nothofagus species occurring on infertile soils.

Identifying biogeochemical processes beneath stormwater infiltration ponds in support of a new best management practice for groundwater protection

USGS Publications Warehouse

O'Reilly, Andrew M.; Chang, Ni-Bin; Wanielista, Martin P.; Xuan, Zhemin; Schirmer, Mario; Hoehn, Eduard; Vogt, Tobias

2011-01-01

 When applying a stormwater infiltration pond best management practice (BMP) for protecting the quality of underlying groundwater, a common constituent of concern is nitrate. Two stormwater infiltration ponds, the SO and HT ponds, in central Florida, USA, were monitored. A temporal succession of biogeochemical processes was identified beneath the SO pond, including oxygen reduction, denitrification, manganese and iron reduction, and methanogenesis. In contrast, aerobic conditions persisted beneath the HT pond, resulting in nitrate leaching into groundwater. Biogeochemical differences likely are related to soil textural and hydraulic properties that control surface/subsurface oxygen exchange. A new infiltration BMP was developed and a full-scale application was implemented for the HT pond. Preliminary results indicate reductions in nitrate concentration exceeding 50% in soil water and shallow groundwater beneath the HT pond.

The use of soil pollen to determine the sex of overhead individuals of a temperate dioecious shrub.

PubMed

Sugiyama, Anna; Shichi, Koji; Masaki, Takashi; Hubbell, Stephen P

2017-04-01

In dioecious species, determining the sex of individual plants from one-time phenological observations is rarely feasible when some individuals capable of reproducing are not flowering or fruiting at the time of observation. Currently, sexing those individuals requires long-term phenological data on individuals and populations, but such data are rarely available or feasible to collect. We tested the hypothesis that differences in soil pollen concentrations beneath the crowns of female and male plants would exist and be sufficient to reliably determine the sex of the individual plant overhead in a dioecious species. We predicted that soil pollen concentrations beneath male plants would be significantly higher than beneath female plants because only males produce pollen and pollen should accumulate in the soil underneath the male plants over repeated flowering events. We collected samples from surface soil under both sexes of the insect-pollinated dioecious shrub, Aucuba japonica (Garryaceae). Pollen grains were present in surface soil in both Oe and A horizons, and mean pollen concentration under males was significantly higher than under females. Pollen concentrations beneath males were positively correlated with male plant height, potentially reflecting greater pollen production by larger individuals. Considering the small plant size and relatively low pollen production of A. japonica , this method may hold promise for sexing other dioecious species in the absence of direct phenological data. Our phenology-free and relatively low-cost method for sexing dioecious plants may be especially useful in tropical forests where many species are dioecious. © 2017 Botanical Society of America.

Evaluation of potential site for mineral processing plant

NASA Astrophysics Data System (ADS)

Izwan Ishak, Muhamad Noor; Sipaun, Susan Maria; Mustapha, Ismail; Fahmi Engku Chik, Engku Mohd; Abdullah, Nurliyana; Affandi Mahmood, Airwan

2018-01-01

Nuclear moisture-density gauge is a type of instrument for measuring density and moisture of the material in a relatively thin zone beneath a surface of the material by using low activity of neutron and gamma radiation source. Density and moisture content data of the compacted layers are needed to determine the degree of compaction of soils, aggregate, concrete, asphalt or other materials used in civil engineering works. A gamma radiation source is mounted inside gauge housing with the source rod vertically extended to various depth positions. Direct transmission gamma radiation technique is used to obtain the count reading for the number of photons emitted before it is converted into density reading by microprocessor. This paper presents the inspection technique and results for the measurement of soil moisture and density carried out at potential site for mineral processing plant, Malaysian Nuclear Agency. Primarily, the experiment was conducted to ensure the compaction of ground is suitable for the plant construction. From the calculation, the percentages of soil wet density compaction (%WD Compact) are within acceptable limits with respect to the standard compacted wet soil density measured in the laboratory.

Trees and Weathering: Using Soil Petrographic and Chemical Analyses to Compare the Relative Weathering Effects of Gymnosperms and Angiosperms in the Cascade Mountains of Washington State, USA

NASA Astrophysics Data System (ADS)

Andrews, M. Y.; Ague, J. J.; Berner, R. A.

2006-12-01

Knowledge of the long-term carbon cycle and its control on atmospheric carbon dioxide levels over the Phanerozoic is crucial to understanding the impending dynamics of contemporary anthropogenic carbon contributions to the atmosphere. One aspect of the long-term carbon cycle that is poorly understood is the role of large vascular plants (trees) in contributing to the chemical weathering of silicate minerals. In particular, little is known about the differences in weathering rates between gymnosperms and angiosperms and how these dissimilarities may have impacted the carbon cycle subsequent to the evolution of angiosperm trees in the Mesozoic. One approach to evaluating these potential differences in weathering is to examine and quantitatively compare the chemistry and petrology of the soil mineral constituents from beneath modern groves of each broad tree type, where the groves have been subject to nearly identical environmental and geological conditions. This particular study focuses on field samples collected along transects through adjacent groves of angiosperms and gymnosperms in the Cascade Mountains of Washington State. Preliminary data demonstrate a significant difference in the soil texture and composition beneath the two types of trees. While soil at each field site has been generated from a homogeneous parent material, and subjected to similar inorganic environmental phenomena, soil density, particle size, and organic content vary across the transects. Soils beneath the angiosperms are denser and have a more clay-like texture, while soils beneath the gymnosperms are more organic-rich and have a sandy texture. Additional macroscopic and microscopic differences in the chemistry and petrology of these soils will illuminate the varied impacts these trees have on the silicate minerals in their immediate environment, and therefore lend insight into the potential impact these groups of organisms have had on the long-term carbon cycle over the past five hundred million years.

Soil microbial activities beneath Stipa tenacissima L. and in surrounding bare soil

NASA Astrophysics Data System (ADS)

Novosadová, I.; Ruiz Sinoga, J. D.; Záhora, J.; Fišerová, H.

2010-05-01

Open steppes dominated by Stipa tenacissima L. constitute one of the most representative ecosystems of the semi-arid zones of Eastern Mediterranean Basin (Iberian Peninsula, North of Africa). These steppes show a higher degree of variability in composition and structure. Ecosystem functioning is strongly related to the spatial pattern of grass tussocks. Soils beneath S. tenacissima grass show higher fertility and improved microclimatic conditions, favouring the formation of "resource islands" (Maestre et al., 2007). On the other hand in "resource islands" and in surrounding bare soil exists the belowground zone of influence. The competition for water and resources between plants and microorganisms is strong and mediated trough an enormous variety of exudates and resource depletion intended to regulate soil microbial communities in the rhizosphere, control herbivory, encourage beneficial symbioses, and change chemical and physical properties in soil (Pugnaire et Armas, 2008). Secondary compounds and allelopathy restrict other species growth and contribute to patchy plant distribution. Active root segregation affects not only neighbourś growth but also soil microbial activities. The objective of this study was to assess the effect of Stipa tenacissima on the key soil microbial activities under controlled incubation conditions (basal and potential respiration; net nitrogen mineralization). The experimental plots were located in the province Almería in Sierra de los Filabres Mountains near the village Gérgal (southeast Spain) in the small catchment which is situated between 1090 - 1165 m a.s.l. The area with extent of 82 000 m2 is affected by soil degradation. The climate is semiarid Mediterranean. The mean annual rainfall is of about 240 mm mostly concentrated in autumn and spring. The mean annual temperature is 13.9° C. The studied soil has a loam to sandy clay texture and is classified as Lithosol (FAO-ISRIC and ISSS, 1998). The vegetation of these areas is an open steppe dominated by Stipa tenacissima. In February 2009 representative soil samples from the top 10 cm were taken beneath grass tussock and from bare soil. Soil samples in three replicates were incubated after rewetting with distilled water (basal microbial activities) and after rewetting with the glucose solution and with the mixture of glucose and peptone solution (potential microbial activities). The CO2, C2H4 evolved under controlled conditions (60% WHC, 24°C) during a 37-day aerobic incubation were determined. Ammonia and nitrate nitrogen were estimated in percolates after simulated rainfall (on the 16th day of incubation) and in the incubated soil samples at the end of incubation. Net ammonification and net nitrification rates were determined by subtracting initial soil mineral N from both mineral N in percolates plus final mineral N contents at 37th day. Basal, potential microbial respiration and net nitrification in the soils beneath S. tenacissima were, in general, not significantly different from the bare soils. The differences between plant-covered soil and bare soil in cumulative values of CO2 production and in amounts of accumulated NO3--N (net nitrification) were less than ± 10%. Greater differences were found in the net ammonification, which were higher beneath S. tenacissima, mainly in the control (basal activities) variant (about 38 %). Significantly less ethylene produced by microbial activity in soils beneath S. tenacissima after the addition of glucose indicates the dependence of rhizospheric microbial communities on available carbon compounds mainly from root exudates. It can be concluded, similarly as published Goberna et al., (2007), that the distribution of soil microbial properties in semi-arid Mediterranean ecosystems is not necessarily associated with the patchy plant distribution and that some microbial activities characteristics can be unexpectedly homogenous.

Exhibition

Science.gov Websites

It! What is Soil? Chip Off the Old Block Soil Forming Factors Matters of Life and Death Underneath It have been sizing up soils. Today, soil scientists analyze soils and predict how they will behave. But Big Picture TheBigPicture How well do you know the world beneath your feet? Take our Soil Quiz and

Exploring the World Beneath Your Feet.

ERIC Educational Resources Information Center

Flass, Christine A.

1984-01-01

A clod of soil contains a multitude of different organisms that can be used to teach students about the invaluable services of soil-dwellers. Activities presented are identifying vertebrate and invertebrate soil-dwellers, learning functions of earthworms, conducting a soil 'population survey', starting a worm culture, and separating anthropods…

KSC-2011-7762

NASA Image and Video Library

2011-11-08

CAPE CANAVERAL, Fla. – In the Granular Mechanics and Regolith Operations (GMRO) Lab at NASA's Kennedy Space Center in Florida, pieces of the Surveyor 3 spacecraft returned from the lunar surface on the Apollo 12 mission are available for examination by the lab's staff. The GMRO Lab is one of several labs located in NASA's Space Life Sciences Laboratory (SLSL) facility. The lab is staffed by three physicists, six mechanical or aerospace engineers and several technicians who are studying how the rocket exhaust of landing vehicles affects lunar and Martian science missions, including the sandblasting of instruments with soil and dust ejecta and the disturbance or contamination of soil beneath the lander. For more information on the GMRO Lab, see p. 7 of the Spaceport News dated Nov. 11, 2011, at http://www.nasa.gov/centers/kennedy/pdf/603285main_nov11-2011.pdf. Photo credit: NASA/Jim Grossmann

KSC-2011-7761

NASA Image and Video Library

2011-11-08

CAPE CANAVERAL, Fla. – In the Granular Mechanics and Regolith Operations (GMRO) Lab at NASA's Kennedy Space Center in Florida, Dr. Philip Metzger examines under a microscope a piece of the Surveyor 3 spacecraft returned from the lunar surface on the Apollo 12 mission. The GMRO Lab is one of several labs located in NASA's Space Life Sciences Laboratory (SLSL) facility. The lab is staffed by three physicists, six mechanical or aerospace engineers and several technicians who are studying how the rocket exhaust of landing vehicles affects lunar and Martian science missions, including the sandblasting of instruments with soil and dust ejecta and the disturbance or contamination of soil beneath the lander. For more information on the GMRO Lab, see p. 7 of the Spaceport News dated Nov. 11, 2011, at http://www.nasa.gov/centers/kennedy/pdf/603285main_nov11-2011.pdf. Photo credit: NASA/Jim Grossmann

KSC-2011-7763

NASA Image and Video Library

2011-11-08

CAPE CANAVERAL, Fla. – In the Granular Mechanics and Regolith Operations (GMRO) Lab at NASA's Kennedy Space Center in Florida, a piece of the Surveyor 3 spacecraft returned from the lunar surface on the Apollo 12 mission is available for examination by the lab's staff. The GMRO Lab is one of several labs located in NASA's Space Life Sciences Laboratory (SLSL) facility. The lab is staffed by three physicists, six mechanical or aerospace engineers and several technicians who are studying how the rocket exhaust of landing vehicles affects lunar and Martian science missions, including the sandblasting of instruments with soil and dust ejecta and the disturbance or contamination of soil beneath the lander. For more information on the GMRO Lab, see p. 7 of the Spaceport News dated Nov. 11, 2011, at http://www.nasa.gov/centers/kennedy/pdf/603285main_nov11-2011.pdf. Photo credit: NASA/Jim Grossmann

3D soil structure characterization of Biological Soil Crusts from Alpine Tarfala Valley

NASA Astrophysics Data System (ADS)

Mele, Giacomo; Gargiulo, Laura; Zucconi, Laura; D'Acqui, Luigi; Ventura, Stefano

2017-04-01

Cyanobacteria filaments, microfungal hyphae, lichen rhizinae and anchoring rhizoids of bryophytes all together contribute to induce formation of structure in the thin soil layer beneath the Biological Soil Crusts (BSCs). Quantitative assessment of the soil structure beneath the BSCs is primarily hindered by the fragile nature of the crusts. Therefore, the role of BSCs in affecting such soil physical property has been rarely addressed using direct measurements. In this work we applied non-destructive X-ray microtomography imaging on five different samples of BSCs collected in the Alpine Tarfala Valley (northern Sweden), which have already been characterized in terms of fungal biodiversity in a previous work. We obtained images of the 3D spatial organization of the soil underneath the BSCs and characterized its structure by applying procedures of image analysis allowing to determine pore size distribution, pore connectivity and aggregate size distribution. Results has then been correlated with the different fungal assemblages of the samples.

Sensible heat balance measurements of soil water evaporation beneath a maize canopy

USDA-ARS?s Scientific Manuscript database

Soil water evaporation is an important component of the water budget in a cropped field. Few methods are available for continuous and independent measurement of soil water evaporation. A sensible heat balance (SHB) approach has recently been demonstrated for continuously determining soil water evapo...

Horizontally opposed trunnion forward engine mount system supported beneath a wing pylon

NASA Technical Reports Server (NTRS)

Seaquist, John D. (Inventor); Culbertson, Chris (Inventor)

2000-01-01

The present invention relates to an engine mount assembly for supporting an aircraft engine in aft-cantilevered position beneath the aircraft wing. The assembly includes a pair forward engine mounts positioned on opposite sides of an integrally formed yoke member wrapped about the upper half of the engine casing. Each side of the yoke is preferably configured as an A-shaped frame member with the bottom portions joining each other and the pylon. To prevent backbone bending of the engine trunnion assembly, the forward engine mounts supported at opposite ends of the yoke engage the casing along its centerline. The trunnion assembly is preferably constructed of high strength titanium machined and/or forged.

Underneath It All

Science.gov Websites

It! What is Soil? Chip Off the Old Block Soil Forming Factors Matters of Life and Death Underneath It Soil 4 Toxic Soil 5 Wildfires and Mudslides >> Underneath It All Soils are the foundations on well do you know the world beneath your feet? Click here to take our Soil Quiz and find out! Copyright

KSC-07pd1550

NASA Image and Video Library

2007-06-18

KENNEDY SPACE CENTER, FLA. -- The truck and transporter carrying the first stage of a Delta II rocket pull beneath the mobile service tower on Launch Pad 17-A at Cape Canaveral Air Force Station. The rocket is the launch vehicle for the Phoenix spacecraft, targeted for launch on Aug. 3,heading for Mars. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Amanda Diller

KSC-07pd1552

NASA Image and Video Library

2007-06-18

KENNEDY SPACE CENTER, FLA. -- On Launch Pad 17-A at Cape Canaveral Air Force Station, the first stage of a Delta II rocket is raised off the transporter beneath the mobile service tower. The rocket is the launch vehicle for the Phoenix spacecraft, targeted for launch on Aug. 3 heading for Mars. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Amanda Diller

Soil water stable isotopes reveal evaporation dynamics at the soil-plant-atmosphere interface of the critical zone

NASA Astrophysics Data System (ADS)

Sprenger, Matthias; Tetzlaff, Doerthe; Soulsby, Chris

2017-07-01

Understanding the influence of vegetation on water storage and flux in the upper soil is crucial in assessing the consequences of climate and land use change. We sampled the upper 20 cm of podzolic soils at 5 cm intervals in four sites differing in their vegetation (Scots Pine (Pinus sylvestris) and heather (Calluna sp. and Erica Sp)) and aspect. The sites were located within the Bruntland Burn long-term experimental catchment in the Scottish Highlands, a low energy, wet environment. Sampling took place on 11 occasions between September 2015 and September 2016 to capture seasonal variability in isotope dynamics. The pore waters of soil samples were analyzed for their isotopic composition (δ2H and δ18O) with the direct-equilibration method. Our results show that the soil waters in the top soil are, despite the low potential evaporation rates in such northern latitudes, kinetically fractionated compared to the precipitation input throughout the year. This fractionation signal decreases within the upper 15 cm resulting in the top 5 cm being isotopically differentiated to the soil at 15-20 cm soil depth. There are significant differences in the fractionation signal between soils beneath heather and soils beneath Scots pine, with the latter being more pronounced. But again, this difference diminishes within the upper 15 cm of soil. The enrichment in heavy isotopes in the topsoil follows a seasonal hysteresis pattern, indicating a lag time between the fractionation signal in the soil and the increase/decrease of soil evaporation in spring/autumn. Based on the kinetic enrichment of the soil water isotopes, we estimated the soil evaporation losses to be about 5 and 10 % of the infiltrating water for soils beneath heather and Scots pine, respectively. The high sampling frequency in time (monthly) and depth (5 cm intervals) revealed high temporal and spatial variability of the isotopic composition of soil waters, which can be critical, when using stable isotopes as tracers to assess plant water uptake patterns within the critical zone or applying them to calibrate tracer-aided hydrological models either at the plot to the catchment scale.

The Resource beneath Our Feet

ERIC Educational Resources Information Center

Clary, Renee

2015-01-01

This article describes activities in which students sample, investigate, classify, and compare characteristics (i.e., texture, color, density, porosity) of local soils, evaluating whether the soils are healthy or at risk. Students investigate correlations between geology and geography, predict which soil types may go extinct in their state, and…

Using Lunar Module Shadows To Scale the Effects of Rocket Exhaust Plumes

NASA Technical Reports Server (NTRS)

2008-01-01

Excavating granular materials beneath a vertical jet of gas involves several physical mechanisms. These occur, for example, beneath the exhaust plume of a rocket landing on the soil of the Moon or Mars. We performed a series of experiments and simulations (Figure 1) to provide a detailed view of the complex gas-soil interactions. Measurements taken from the Apollo lunar landing videos (Figure 2) and from photographs of the resulting terrain helped demonstrate how the interactions extrapolate into the lunar environment. It is important to understand these processes at a fundamental level to support the ongoing design of higher fidelity numerical simulations and larger-scale experiments. These are needed to enable future lunar exploration wherein multiple hardware assets will be placed on the Moon within short distances of one another. The high-velocity spray of soil from the landing spacecraft must be accurately predicted and controlled or it could erode the surfaces of nearby hardware. This analysis indicated that the lunar dust is ejected at an angle of less than 3 degrees above the surface, the results of which can be mitigated by a modest berm of lunar soil. These results assume that future lunar landers will use a single engine. The analysis would need to be adjusted for a multiengine lander. Figure 3 is a detailed schematic of the Lunar Module camera calibration math model. In this chart, formulas relating the known quantities, such as sun angle and Lunar Module dimensions, to the unknown quantities are depicted. The camera angle PSI is determined by measurement of the imaged aspect ratio of a crater, where the crater is assumed to be circular. The final solution is the determination of the camera calibration factor, alpha. Figure 4 is a detailed schematic of the dust angle math model, which again relates known to unknown parameters. The known parameters now include the camera calibration factor and Lunar Module dimensions. The final computation is the ejected dust angle, as a function of Lunar Module altitude.

Homogenization of the soil surface following fire in semiarid grasslands

Treesearch

Carleton S. White

2011-01-01

Semiarid grasslands accumulate soil beneath plant "islands" that are raised above bare interspaces. This fine-scale variation in microtopographic relief is plant-induced and is increased with shrub establishment. Research found that fire-induced water repellency enhanced local-scale soil erosion that reduced variation in microtopographic relief, suggesting...

REDUCTIVE DETOXIFICATION AND IMMOBILIZATION OF CHROMATE PRESENT IN SOILS

EPA Science Inventory

Sodium dithionite was used to treat a chromium source zone in soils beneath an old chrome plating shop. The sodium dithionite was injected as a buffered solution into the soils to transform the chromium from the oxidized (+6) state to the reduced (+3) state. Once reduced the chro...

IN-SITU REMEDIATION OF CHROMIUM-CONTAMINATED SOILS AND SEDIMENTS USING SODIUM DITHIONITE

EPA Science Inventory

Soil cores were collected from beneath an old chrome plating shop at the USCG Support Center near Elizabeth City, NC in order to determine the extent of chromium contamination in the soils and ground water. Selective extractions were used to assess the chemical speciation and di...

A method for installing zero-tension pan and wick lysimeters in soil

USDA-ARS?s Scientific Manuscript database

Zero-tension pan lysimeters and passive capillary fiberglass wick lysimeters are useful in determining water quality and volumetric aspects of subsurface water flow. Installation of pan and wick lysimeters beneath undisturbed soil may be complicated by the tendency for the soil to cave-in as the lys...

21. Generator Room (basement beneath Blacksmith Shop): view looking north ...

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

21. Generator Room (basement beneath Blacksmith Shop): view looking north showing remains of 1923 six-cylinder Studebaker engine and a dynamo - Ben Thresher's Mill, State Aid No. 1, Barnet, Caledonia County, VT

Proceedings of the California Forest Soils Council Conference on Forest Soils Biology and Forest Management

Treesearch

Robert F. Powers; Donald L. Hauxwell; Gary M. Nakamura

2000-01-01

Biotic properties of forest soil are the linkages connecting forest vegetation with an inert rooting medium to create a dynamic, functioning ecosystem. But despite the significance of these properties, managers have little awareness of the biotic world beneath their feet. Much of our working knowledge of soil biology seems anchored in myth and misunderstanding. To...

Soil water evaporation and crop residues

USDA-ARS?s Scientific Manuscript database

Crop residues have value when left in the field and also when removed from the field and sold as a commodity. Reducing soil water evaporation (E) is one of the benefits of leaving crop residues in place. E was measured beneath a corn canopy at the soil suface with nearly full coverage by corn stover...

Interpreting geologic maps for engineering purposes: Hollidaysburg quadrangle, Pennsylvania

USGS Publications Warehouse

,

1953-01-01

This set of maps has been prepared to show the kinds of information, useful to engineers, that can be derived from ordinary geologic maps. A few additional bits of information, drawn from other sources, are mentioned below. Some of the uses of such maps are well known; they are indispensable tools in the modern search for oil or ore deposits; they are the first essential step in unraveling the story of the earth we live on. Less well known, perhaps, is the fact that topographic and geologic maps contain many of the basic data needed for planning any engineering construction job, big or little. Any structure built by man must fit into the topographic and geologic environment shown on such maps. Moreover, most if not all construction jobs must be based on knowledge of the soils and waters, which also are intimately related to this same environment. The topographic map shows the shape of the land the hills and valleys, the streams and swamps, the man-made features such as roads, railroads, and towns. The geologic map shows the kinds and shapes of the rock bodies that form the land surface and that lie beneath it. These are the facts around which the engineer must build.

Soil heating during burning of forest slash piles and wood piles

Treesearch

Matt D. Busse; Carol J. Shestak; Ken R. Hubbert

2013-01-01

Pile burning of conifer slash is a common fuel reduction practice in forests of the western United States that has a direct, yet poorly quantified effect on soil heating. To address this knowledge gap, we measured the heat pulse beneath hand-built piles ranging widely in fuel composition and pile size in sandy-textured soils of the Lake Tahoe Basin. The soil heat pulse...

Patrick Megonigal

Science.gov Websites

fun when you add water!" How did you come to love soils? I grew up camping and learned to love forests, marshes, deserts, and other wild places. I fell in love with soils later when I learned that they or wetland to camp in without the soil beneath the landscape. Why is dirt more fun when you add water

Effects of Slurry Injector Disk Shape on Reduction of Soil-Machine Resistance during Animal Effluent Application

USDA-ARS?s Scientific Manuscript database

Application of liquid manure to soil is commonly done by injecting the manure beneath the soil surface, to reduce emission of odors and greenhouse gases into the atmosphere and to avoid the spreading of liquid manure on leaves of crop plants. This manure injection is often done using knife-like inj...

Persistence and efficacy of termiticides used in preconstruction treatments to soil in Mississippi

Treesearch

J.E. Mulrooney; M.K. Davis; T.L. Wagner; R.L. Ingram

2006-01-01

Laboratory and field studies were conducted to determine the persistence and efficacy of termiticides used as preconstruction treatments against subterranean termites. Bifenthrin (0.067%), chlorpyrifos (0.75%), and imidacloprid (0.05%) ( [AI]; wt:wt) were applied to soil beneath a monolithic concrete slab at their minimum labeled rates. Soil samples were taken from...

[Effect of shifting sand burial on evaporation reduction and salt restraint under saline water irrigation in extremely arid region].

PubMed

Zhang, Jian-Guo; Zhao, Ying; Xu, Xin-Wen; Lei, Jia-Qiang; Li, Sheng-Yu; Wang, Yong-Dong

2014-05-01

The Taklimakan Desert Highway Shelterbelt is drip-irrigated with high saline groundwater (2.58-29.70 g x L(-1)), and shifting sand burial and water-salt stress are most common and serious problems in this region. So it is of great importance to study the effect of shifting sand burial on soil moisture evaporation, salt accumulation and their distribution for water saving, salinity restraint, and suitable utilization of local land and water resources. In this study, Micro-Lysimeters (MLS) were used to investigate dynamics of soil moisture and salt under different thicknesses of sand burial (1, 2, 3, 4, and 5 cm), and field control experiments of drip-irrigation were also carried out to investigate soil moisture and salt distribution under different thicknesses of shifting sand burial (5, 10, 15, 20, 25, 30, 35, and 40 cm). The soil daily and cumulative evaporation decreased with the increase of sand burial thickness in MLS, cumulative evaporation decreased by 2.5%-13.7% compared with control. And evaporative inhibiting efficiency increased with sand burial thickness, evaporative inhibiting efficiency of 1-5 cm sand burial was 16.7%-79.0%. Final soil moisture content beneath the interface of sand burial increased with sand burial thickness, and it increased by 2.5%-13.7% than control. The topsoil EC of shifting sand in MLS decreased by 1.19-6.00 mS x cm(-1) with the increasing sand burial thickness, whereas soil salt content beneath the interface in MLS increased and amplitude of the topsoil salt content was higher than that of the subsoil. Under drip-irrigation with saline groundwater, average soil moisture beneath the interface of shifting sand burial increased by 0.4% -2.0% compare with control, and the highest value of EC was 7.77 mS x cm(-1) when the sand burial thickness was 10 cm. The trend of salt accumulation content at shifting sand surface increased firstly, and then decreased with the increasing sand burial thickness. Soil salt contents beneath the interface of shifting sand burial were much lower than that of shifting sand surface. 35 cm was the critical sand burial thickness for water-saving and salt restraint. In summary, sand burial had obvious inhibition effects on soil evaporation and salt accumulation, so maybe it could be used to save water and reduce salt accumulation in arid shifting desert areas.

The effect of the halophytic shrub Lycium ruthenium (Mutt) on selected soil properties of a desert ecosystem in central Iran

Treesearch

Gholam Ali Jalali; Hossein Akbarian; Charles Rhoades; Hamed Yousefzadeh

2012-01-01

We compared soil properties beneath naturally-occurring patches of Lycium ruthenicum Murray (fam. Solanaceae) to evaluate the shrub’s potential to improve the fertility of saline soils. Soil pH, total nitrogen and carbon and extractable potassium, magnesium and phosphorus were respectively significantly higher in the A and B horizons of Lycium shrub patches...

Influence of high-frequency ambient pressure pumping on carbon dioxide efflux from soil

Treesearch

Eugene S. Takle; William J. Massman; James R. Brandle; R. A. Schmidt; Xinhua Zhou; Irina V. Litvina; Rick Garcia; Geoffrey Doyle; Charles W. Rice

2004-01-01

We report measurements at 2Hz of pressure fluctuations at and beneath the soil in an agricultural field with dry soil and no vegetation. The objective of our study was to examine the possible role of pressure fluctuations produced by fluctuations in ambient wind on the efflux of CO2 at the soil surface.We observed that pressure fluctuations penetrate to 50 cm in the...

The Use of Commercial Remote Sensing Systems in Predicting Helicopter Brownout Conditions

DTIC Science & Technology

2009-09-01

REFERENCES Anthoni, J. F. (2000). Soil Erosion and Conservation – Part 2. Retrieved 15 August 2009, from http://www.seafriends.org.nz/ enviro / soil ... soils susceptible to helicopter brownout. Helicopter brownout occurs when downwash disturbs the dust and sand beneath the aircraft during takeoff...destruction, as well as personnel injury or death. The likelihood of helicopter brownout is related to soil moisture content, particle size distribution, and

Application of Soil Nailing Technique for Protection and Preservation Historical Buildings

NASA Astrophysics Data System (ADS)

Kulczykowski, Marek; Przewłócki, Jarosław; Konarzewska, Bogusława

2017-10-01

Soil nailing is one of the recent in situ techniques used for soil improvement and in stabilizing slopes. The process of soil nailing consists of reinforcing the natural ground with relatively small steel bars or metal rods, grouted in the pre-drilled holes. This method has a wide range of applications for stabilizing deep excavations and steep slopes. Soil nailing has recently become a very common method of slope stabilisation especially where situated beneath or adjacent to historical buildings. Stabilisation by nails drilled into existing masonry structures such as failing retaining walls abutments, provide long term stability without demolition and rebuilding costs. Two cases of soil nailing technology aimed at stabilising slopes beneath old buildings in Poland are presented in this paper. The first concerns application of this technology to repair a retaining wall supporting the base of the dam at the historic hydroelectric power plant in Rutki. The second regards a concept of improving the slope of the Castle Hill in Sandomierz. An analysis of the slope stability for the latter case, using stabilisation technique with the piling system and soil nailing was performed. Some advantages of soil nailing especially for protection of historical buildings, are also underlined. And, the main results of an economic comparison analysis are additionally presented.

Cratering Soil by Impinging Jets of Gas, with Application to Landing Rockets on Planetary Surfaces

NASA Technical Reports Server (NTRS)

Metzger, Philip T.; Vu, B. T.; Taylor, D. E.; Kromann, M. J.; Fuchs, M.; Yutko, B.; Dokos, A.; Immer, Christopher D.; Lane, J. E.; Dunkel, Michael B.;

Non-labile Soil Nitrogen Retention beneath Three Tree Species in a Tropical Plantation

Treesearch

Jason P. Kaye; Dan Binkley; Xiaoming Zou

2002-01-01

Soil organic matter is the largest sink for N additions to forests. Species composition may affect soilNretention by altering the amount or proportion of added N stored in non-labile organic pools. We measured 15N tracer retention in labile and non-labile pools of surface (0–20 cm) mineral soils, 7 yr after the tracer was applied to a 9 yr-old Puerto Rican tree...

The influence of soil color on seedbed microclimate and seedling demographics of a perennial bunchgrass

USDA-ARS?s Scientific Manuscript database

Perennial bunchgrasses are critical to maintaining sagebrush plant communities but seeding of native bunchgrasses following fire has met with only limited success. Previous research indicates that blackened soils beneath burned sagebrush canopies have increased seeding success for perennial bunchgr...

Assessing the impact of preload on pyrite-rich sediment and groundwater quality.

PubMed

Karikari-Yeboah, Ohene; Addai-Mensah, Jonas

2017-02-01

Pyrite-rich sediments would, invariably, undergo redox reactions which would lead to acidic aqueous environment containing solubilized toxic metal species. When such sediments are subjected to preload, a technique employed by geotechnical engineers to improve the load-bearing capacity of highly compressible formation, transient flow of pore water, accompanied by acidity transfer, would occur as a response. Despite the concomitant environmental and socio-economic significance, to date, there has been limited interdisciplinary research on the underpinning geotechnical engineering and geo-environmental science issues for pyrite-rich sediments under preload. In this study, we investigate the effect of pyrite-rich sediment pore water transfer under preload surcharge on the receiving environment and the impact on the groundwater speciation and quality. Sediment samples were obtained at close depth intervals from boreholes established within pristine areas and those subjected to the preload application. Soil and pore water samples were subjected to solid/solution speciation, moisture contents, soil pH and the Atterberg Limits' analyses using standard analytical techniques and methods. Standpipes were also installed in the boreholes for groundwater sampling and in situ monitoring of water quality parameters. It is shown that the imposition of preload surcharge over pyritic sediment created a reducing environment rich in SO 4 2- , iron oxide minerals and organic matter. This reducing environment fostered organic carbon catabolism to generate excess pyrite and bicarbonate alkalinity, which would invariably impact adversely on soil quality and plant growth. These were accompanied by increase in pH, dissolved Al, Ca, Mg and K species beneath the surcharge.

IN-SITU TREATMENT OF CHROMIUM SOURCE AREA USING REDOX MANIPULATION

EPA Science Inventory

Sodium dithionite was used to treat a chromium source zone in soils beneath an old chrome plating shop. The sodium dithionite was injected as a buffered solution into the soils to transform the chromium from the oxidized (+6) state to the reduced (+3) state. Once reduced the chro...

Pilot-scale vadose zone microbial biobarriers removed nitrate leaching from a cattle corral

USDA-ARS?s Scientific Manuscript database

activities that involve animal wastes can result in the contamination of subsurface soils by nitrates. In saturated or nearly saturated soils microbial biobarriers are a common method used to remove contaminants from water. This field study was conducted beneath a cattle pen in northeast Colorado a...

The Diversity of Arbuscular Mycorrhizal Fungi Amplified from Grapevine Roots (Vitis vinifera L.) in Oregon Vineyards is Seasonally Stable and Influenced by Soil and Vine Age

USDA-ARS?s Scientific Manuscript database

The diversity of arbuscular mycorrhizal fungi (AMF) associated with the roots of grapevines in 10 commercial Oregon vineyards was assessed by examining spores in soil and by amplifying mycorrhizal DNA from ‘Pinot noir’ root extracts. Seventeen spore morphotypes were found in the soil beneath the vin...

Microbial community composition and function beneath temperate trees exposed to elevated atmospheric carbon dioxide and ozone

Treesearch

Rebecca L. Phillips; Donald R. Zak; William E. Holmes; David C. White

2002-01-01

We hypothesized that changes in plant growth resulting from atmospheric CO2 and O3 enrichment would alter the flow of C through soil food webs and that this effect would vary with tree species. To test this idea, we traced the course of C through the soil microbial community using soils from the free-air CO2...

Spatio-temporal Variation in Soil Water in a Semiarid Woodland: Implications for Woody Plant Encroachment

NASA Astrophysics Data System (ADS)

Bresehars, D. D.; Myers, O. B.; Barnes, F. J.

2003-12-01

Woody plant encroachment in dryland ecosystems is an issue of global concern, yet mechanisms related to encroachment are poorly understood. Mechanisms associated with woody plant encroachment likely relate to soil water dynamics, yet few long-term data sets exist to evaluate soil water heterogeneity. Here we highlight how soil water varies both temporally (wet vs. dry years and snow vs. rain dominated months) and spatially (vertically with depth and horizontally beneath vs. between the canopies of woody plants). We measured soil water content using neutron probe over a 15-year period in a pinyon-juniper woodland at the Mesita del Buey Research Site in northern New Mexico. Our objectives included assessing (1) the temporal variability of soil water, both as a function of depth and as a function of cover (canopy patches beneath trees, intercanopy patches between trees, and edges between the two patch types); and (2) implications for the vertical and horizontal distributions of plant-available water. Our results highlight (1) large temporal variations in soil water availability, driven largely by differences in winter precipitation, and (2) the potential importance of considering horizontal as well as vertical heterogeneity in soil moisture. The spatio-temporal variation in soil water that we quantify highlights the potential complexity of changes in the water budget that could be associated with woody plant encroachment and emphasizes the importance of considering horizontal as well as vertical heterogeneity in soil water in improving our understanding of mechanisms associated with woody plant encroachment.

Improvement of Liquefiable Foundation Conditions Beneath Existing Structures.

DTIC Science & Technology

1985-08-01

filter zones, and drains. Drilling fluids can cause hydraulic fracturing . These hazards can lead to to piping and hvdraulic fracturing Compression . 7...with results of piping and hydraulic fracturing (Continued) * Site conditions have been classified into three cases; Case 1 is for beneath -d...which could lead to piping and hydraulic fracturing Soil Reinforcement 16. Vibro-replacement See methods 2 and 3 stone and sand columns applicable to

Fate and Transport of Tungsten at Camp Edwards Small Arms Ranges

DTIC Science & Technology

2007-08-01

area into the lower berm and/or trough. A similar approach was used in the lower berm area with samples collected from soil sloughing from the...bucket au- ger to collect samples beneath the bullet pockets and the trough. A multi - increment, subsurface soil sample was made by combining the...range. From these soil profiles, a total of 72 multi -increment subsurface soil sam- ples was collected (Table 2). The auger was cleaned between holes

Non-labile Soil 15Nitrogen Retention beneath Three Tree Species in a Tropical Plantation

Treesearch

Jason P. Kaye; Dan Binkley; Xiaoming Zou

2002-01-01

Soil organic matter is the largest sink for N additions to forests.Species composition may affect soilNretention by altering the amount or proportion of added N stored in non-labile organic pools. We measured 15N tracer retention in labile and non-labile pools of surface (0–20 cm) mineral soils, 7 yr after the tracer was applied to a 9 yr-old Puerto Rican tree...

Assessment of concentrations of trace elements in ground water and soil at the Small-Arms Firing Range, Shaw Air Force Base, South Carolina

USGS Publications Warehouse

Landmeyer, J.E.

1994-01-01

Ground-water samples were collected from four shallow water-table aquifer observation wells beneath the Small-Arms Firing Range study area at Shaw Air Force Base. Water-chemistry analyses indicated that total lead concentrations in shallow ground water beneath the study area do not exceed the U.S. Environmental Protection Agency maximum contaminant level established for lead in drinking water (0.05 milligrams per liter). All other trace element total concentrations in ground water beneath the study area were at or below the detection limit of the analytical methodology.

Final report of the decontamination and decommissioning of Building 18 at the Grand Junction Projects Office Facility

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

Widdop, M.R.

1996-08-01

The U.S. Department of Energy (DOE) Grand Junction Projects Office (GJPO) occupies a 61.7-acre facility along the Gunnison River near Grand Junction, Colorado. This site was contaminated with uranium ore and mill tailings during uranium refining activities of the Manhattan Engineer District and during pilot milling experiments conducted for the U.S. Atomic Energy Commission`s domestic uranium procurement program. The DOE Defense Decontamination and Decommissioning Program established the GJPO Remedial Action Project to clean up and restore the facility lands, improvements, and the underlying aquifer. The site contractor for the facility, Rust Geotech, also is the remedial action contractor. The soilmore » beneath Building 18 was found to be radiologically contaminated; the building was not contaminated. The soil was remediated in accordance with identified standards. Building 18 and the underlying soil can be released for unlimited exposure and unrestricted use. This document was prepared in response to a DOE request for an individual final report for each contaminated GJPO building.« less

Soil variability in engineering applications

NASA Astrophysics Data System (ADS)

Vessia, Giovanna

2014-05-01

Natural geomaterials, as soils and rocks, show spatial variability and heterogeneity of physical and mechanical properties. They can be measured by in field and laboratory testing. The heterogeneity concerns different values of litho-technical parameters pertaining similar lithological units placed close to each other. On the contrary, the variability is inherent to the formation and evolution processes experienced by each geological units (homogeneous geomaterials on average) and captured as a spatial structure of fluctuation of physical property values about their mean trend, e.g. the unit weight, the hydraulic permeability, the friction angle, the cohesion, among others. The preceding spatial variations shall be managed by engineering models to accomplish reliable designing of structures and infrastructures. Materon (1962) introduced the Geostatistics as the most comprehensive tool to manage spatial correlation of parameter measures used in a wide range of earth science applications. In the field of the engineering geology, Vanmarcke (1977) developed the first pioneering attempts to describe and manage the inherent variability in geomaterials although Terzaghi (1943) already highlighted that spatial fluctuations of physical and mechanical parameters used in geotechnical designing cannot be neglected. A few years later, Mandelbrot (1983) and Turcotte (1986) interpreted the internal arrangement of geomaterial according to Fractal Theory. In the same years, Vanmarcke (1983) proposed the Random Field Theory providing mathematical tools to deal with inherent variability of each geological units or stratigraphic succession that can be resembled as one material. In this approach, measurement fluctuations of physical parameters are interpreted through the spatial variability structure consisting in the correlation function and the scale of fluctuation. Fenton and Griffiths (1992) combined random field simulation with the finite element method to produce the Random Finite Element Method (RFEM). This method has been used to investigate the random behavior of soils in the context of a variety of classical geotechnical problems. Afterward, some following studies collected the worldwide variability values of many technical parameters of soils (Phoon and Kulhawy 1999a) and their spatial correlation functions (Phoon and Kulhawy 1999b). In Italy, Cherubini et al. (2007) calculated the spatial variability structure of sandy and clayey soils from the standard cone penetration test readings. The large extent of the worldwide measured spatial variability of soils and rocks heavily affects the reliability of geotechnical designing as well as other uncertainties introduced by testing devices and engineering models. So far, several methods have been provided to deal with the preceding sources of uncertainties in engineering designing models (e.g. First Order Reliability Method, Second Order Reliability Method, Response Surface Method, High Dimensional Model Representation, etc.). Nowadays, the efforts in this field have been focusing on (1) measuring spatial variability of different rocks and soils and (2) developing numerical models that take into account the spatial variability as additional physical variable. References Cherubini C., Vessia G. and Pula W. 2007. Statistical soil characterization of Italian sites for reliability analyses. Proc. 2nd Int. Workshop. on Characterization and Engineering Properties of Natural Soils, 3-4: 2681-2706. Griffiths D.V. and Fenton G.A. 1993. Seepage beneath water retaining structures founded on spatially random soil, Géotechnique, 43(6): 577-587. Mandelbrot B.B. 1983. The Fractal Geometry of Nature. San Francisco: W H Freeman. Matheron G. 1962. Traité de Géostatistique appliquée. Tome 1, Editions Technip, Paris, 334 p. Phoon K.K. and Kulhawy F.H. 1999a. Characterization of geotechnical variability. Can Geotech J, 36(4): 612-624. Phoon K.K. and Kulhawy F.H. 1999b. Evaluation of geotechnical property variability. Can Geotech J, 36(4): 625-639. Terzaghi K. 1943. Theoretical Soil Mechanics. New York: John Wiley and Sons. Turcotte D.L. 1986. Fractals and fragmentation. J Geophys Res, 91: 1921-1926. Vanmarcke E.H. 1977. Probabilistic modeling of soil profiles. J Geotech Eng Div, ASCE, 103: 1227-1246. Vanmarcke E.H. 1983. Random fields: analysis and synthesis. MIT Press, Cambridge.

Soil temperature and moisture dynamics after experimental irrigation on two contrasting soils on the Santa Rita Experimental Range: Implications for mesquite establishment

Treesearch

Nathan B. English; David G. Williams; Jake F. Weltzin

2003-01-01

We established a large-scale manipulative experiment in a semidesert grassland on the Santa Rita Experimental Range to determine how the recruitment and physiology of woody plants (Prosopis velutina Woot.) are affected by invasive grasses, seasonal precipitation regimes, and underlying soil characteristics. We established 72 2.8-m2 plots beneath six large rainout...

Lead and Antimony Speciation in Shooting Range Soils: Molecular Scale Analysis, Temporal Trends and Mobility

DTIC Science & Technology

2017-11-20

35 Figure 25. Effects of saturation time on Pb concentrations as a function of soil type and column...36 Figure 26. Effects of saturation time on Sb concentrations as a function of soil type and column set (a...representation of the oxygen -terminated full layer termination surface of hematite ( ) (second octahedral layer and those beneath are not shown for clarity) ; (D

Influence of red alder on chemical properties of a clay loam soil in western Washington.

Treesearch

D.S. DeBell; M.A. Radwan; J.M. Kraft

1983-01-01

Chemical characteristics of mineral soil beneath red alder (Alnus rubra Bong.) stands of various ages were studied. Total nitrogen (N) of the 0-to 20-centimeter (0- to 8-inch) soil layer increased with stand age, and pH of both the 0- to 20-centimeter and 20- to 50-centimeter (8- to 20-inch) layers decreased with stand age. Contents of some mineral...

Factors affecting ground-water quality in Oakland County, Michigan

USGS Publications Warehouse

,

2004-01-01

Ground water is water stored in pores within soil and rock beneath the land surface. When these pores are connected so that water can be transmitted to wells or springs, these bodies of soil and rock are termed aquifers, from two Greek words meaning “water” and “to bear.” 

Evaluation of a New Passive Diffusion Sampler for Monitoring for Soil Gas and Ground Water at Two UST Sites

EPA Science Inventory

Historically, conventional practice to estimate intrusion of fuel vapors from soil and ground water to buildings measures the concentration of BTEX beneath the building using vapor probes or monitoring wells screened across the water table. Standard practice assumes that the co...

Determination of the Basin Structure Beneath European Side of Istanbul

NASA Astrophysics Data System (ADS)

Karabulut, Savas; Cengiz Cinku, Mulla; Thomas, Michael; Lamontagne, Maurice

2016-04-01

Istanbul (near North Anatolian Fault Zone:NAFZ, Turkey) is located in northern part of Sea of Marmara, an area that has been influenced by possible Marmara Earthquakes. The general geology of Istanbul divided into two stratigraphic unit such as sedimentary (from Oligocene to Quaternary Deposits) and bedrock (Paleozoic and Eocene). The bedrock units consists of sand stone, clay stone to Paleozoic age and limestone to Eocene age and sedimentary unit consist of sand, clay, mil and gravel from Oligocene to Quaternary age. Earthquake disaster mitigation studies divided into two important phases, too. Firstly, earthquake, soil and engineering structure problems identify for investigation area, later on strategic emergency plan can prepare for these problems. Soil amplification play important role the disaster mitigation and the site effect analysis and basin structure is also a key parameter for determining of site effect. Some geophysical, geological and geotechnical measurements are requeired to defined this relationship. Istanbul Megacity has been waiting possible Marmara Earthquake and their related results. In order to defined to possible damage potential related to site effect, gravity measurements carried out for determining to geological structure, basin geometry and faults in Istanbul. Gravity data were collected at 640 sites by using a Scientrex CG-5 Autogravity meter Standard corrections applied to the gravity data include those for instrumental drift, Earth tides and latitude, and the free-air and Bouguer corrections. The corrected gravity data were imported into a Geosoft database to create a grid and map of the Bouguer gravity anomaly (grid cell size of 200 m). As a previously results, we determined some lineminants, faults and basins beneath Istanbul City. Especially, orientation of faults were NW-SE direction and some basin structures determined on between Buyukcekmece and Kucukcekmece Lake.

Do evergreen and deciduous trees have different effects on net N mineralization in soil?

PubMed

Mueller, Kevin E; Hobbie, Sarah E; Oleksyn, Jacek; Reich, Peter B; Eissenstat, David M

2012-06-01

Evergreen and deciduous plants are widely expected to have different impacts on soil nitrogen (N) availability because of differences in leaf litter chemistry and ensuing effects on net N mineralization (N(min)). We evaluated this hypothesis by compiling published data on net N(min) rates beneath co-occurring stands of evergreen and deciduous trees. The compiled data included 35 sets of co-occurring stands in temperate and boreal forests. Evergreen and deciduous stands did not have consistently divergent effects on net N(min) rates; net N(min) beneath deciduous trees was higher when comparing natural stands (19 contrasts), but equivalent to evergreens in plantations (16 contrasts). We also compared net N(min) rates beneath pairs of co-occurring genera. Most pairs of genera did not differ consistently, i.e., tree species from one genus had higher net N(min) at some sites and lower net N(min) at other sites. Moreover, several common deciduous genera (Acer, Betula, Populus) and deciduous Quercus spp. did not typically have higher net N(min) rates than common evergreen genera (Pinus, Picea). There are several reasons why tree effects on net N(min) are poorly predicted by leaf habit and phylogeny. For example, the amount of N mineralized from decomposing leaves might be less than the amount of N mineralized from organic matter pools that are less affected by leaf litter traits, such as dead roots and soil organic matter. Also, effects of plant traits and plant groups on net N(min) probably depend on site-specific factors such as stand age and soil type.

Phosphorus vertical migration in aquic brown soil and light chernozem under different phosphorous application rate: a soil column leaching experiment.

PubMed

Zhao, Muqiu; Chen, Xin; Shi, Yi; Zhou, Quanlai; Lu, Caiyan

2009-01-01

A soil column leaching experiment was conducted to study the vertical migration of phosphorus in aquic brown soil and light chernozem under different phosphorus fertilization rates. The results showed that total dissolved phosphorus concentration in the leachates from the two soils was nearly the same, but dissolved inorganic phosphorus concentration was obviously different. In all fertilization treatments, aquic brown soil had a higher content of phosphorus in calcium chloride extracts compared with light chernozem. But Olsen phosphorus content was higher at the soil depth beneath 0-20 cm, and increased with increasing phosphorus application rate.

Soil C and N patterns in a semiarid piñon-juniper woodland: Topography of slope and ephemeral channels add to canopy-intercanopy heterogeneity

USGS Publications Warehouse

Law, Darin J.; Breshears, David D.; Ebinger, Michael H.; Meyer, Clifton W.; Allen, Craig D.

2012-01-01

Carbon and nitrogen are crucial to semiarid woodlands, determining decomposition, production and redistribution of water and nutrients. Carbon and nitrogen are often greater beneath canopies than intercanopies. Upslope vs. downslope position and ephemeral channels might also cause variation in C and N. Yet, few studies have simultaneously evaluated spatial variation associated with canopy–intercanopy patches and topography. We estimated C and N upslope and downslope in an eroding piñon–juniper woodland for canopies beneath piñons (Pinus edulis) and junipers, (Juniperus monosperma), intercanopies, and ephemeral channels. Soil C and N in the surface and profile beneath canopies exceeded that of intercanopies and channels. Relative to intercanopies, channels had more profile C upslope but less downslope (profile N was not significant). Relative to upslope, profile C downslope for intercanopies was greater and for channels was less (profile N was not significant). Relative to profile, surface soil C and N exhibited less heterogeneity. Although some topographic heterogeneity was detected, results did not collectively support our redistribution hypotheses, and we are unable to distinguish if this heterogeneity is due to in situ or redistribution effects. Nonetheless, results highlight finer topographical spatial variation in addition to predominant canopy and intercanopy variation that is applicable for semiarid woodland management.

Investigation of sterols as potential biomarkers for the detection of pig (S. s. domesticus) decomposition fluid in soils.

PubMed

von der Lühe, Barbara; Dawson, Lorna A; Mayes, Robert W; Forbes, Shari L; Fiedler, Sabine

2013-07-10

This study was carried out to evaluate the potential of using cholesterol and coprostanol, as indicators for the detection of decomposition fluid of buried pigs (S. s. domesticus) in soils. In May 2007, four pig carcasses (∼35kg) were buried in shallow graves (∼40 cm depth) at the University of Ontario Institute of Technology in Canada. Two pigs were exhumed after three months (Pig 1, Pig 2) and six months (Pig 3, Pig 4) post burial. Soil samples were collected beneath the pig carcasses (∼40cm depth) and from grave walls (∼15-20 cm depth) as well as from a parallel control site. Coprostanol and cholesterol were extracted from soils, purified with solid phase extraction (SPE) and analysed with gas chromatography/mass spectrometry (GC/MS). A significant increase in cholesterol concentrations (p<0.05) and amounts of coprostanol were detected in soil located beneath the pig carcasses after three months of burial. It is assumed that during the putrefaction and liquefaction stages of decomposition pig fluid which contains cholesterol and coprostanol is released into the underlying soil. Therefore, cholesterol and coprostanol could be used as potential biomarkers to detect the presence of decomposition fluid three months after burial under comparable soil and environmental conditions. Further research is suggested for additional soil sampling before and after three months to investigate the abundance of these and other sterols. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

IN-SITU REDUCTION OF CHROMATE-CONTAMINATED SOILS AND SEDIMENTS BY SODIUM DITHIONITE: A FIELD-SCALE STUDY

EPA Science Inventory

A chrome-plating shop had been the source of discharges of acidic chromium wastes into the soils and groundwater beneath the shop at the USCG Support Center near Elizabeth City, NC. An initial characterization of the site was conducted in 1990 and 1991 to determine the extent of...

76 FR 52022 - Environmental Assessment and Finding of No Significant Impact for License Amendment No. 64 for...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-19

..., namely sub-grade erosion of the erosion protection layer resulting in isolated, shallow incisions of the underlying cover soils. While this issue has resulted in shallow incisions of the underlying cover soils in... layer is 54 inches thick on the cover and the radon barrier is located beneath the frost protection...

Fate of Escherichia coli O157:H7 in manure compost-amended soil and on carrots and onions grown in an environmentally controlled growth chamber.

PubMed

Islam, Mahbub; Morgan, Jennie; Doyle, Michael P; Jiang, Xiuping

2004-03-01

Studies were done to determine the fate of Escherichia coli O157:H7 in manure compost-amended soil and on carrots and green onions grown in an environmentally controlled growth chamber. Commercial dairy cattle manure compost was inoculated with a five-strain mixture of green fluorescent protein-labeled E. coli O157:H7 at 10(7) CFU g(-1) and mixed with unsterilized Tifton sandy loam soil at a ratio of 1:5. Baby carrot or green onion seedlings were planted into the manure compost-amended soil in pots, and soil samples surrounding the plant, edible carrot roots and onion bulb samples, and soil immediately beneath the roots were assayed for E. coli O157:H7 in triplicate at weekly intervals for the first 4 weeks, and every 2 weeks for the remainder of the plant growth cycle (up to 3 months). E. coli O157:H7 cell numbers decreased within 64 days by 3 log CFU/g in soil and soil beneath the roots of green onions and by more than 2 log CFU/g on onions. E. coli O157:H7 survived better during the production of carrots, with a 2.3-log CFU/g reduction in soil and a 1.7-log CFU/g reduction on carrots within 84 days. These results indicate that the type of plant grown is an important factor influencing the survival of E. coli O157:H7 both on the vegetable and in the soil in which the vegetable is grown.

Responses of Tylenchulus semipenetrans to Citrus Fruit Removal: Implications for Carbohydrate Competition

PubMed Central

Duncan, Larry W.; Eissenstat, David M.

1993-01-01

Sixteen mature Valencia orange trees on rough lemon rootstock were selected on the basis of approximately equal, naturally occurring populations of Tylenchulus semipenetrans in soil. In March, fruit 1 cm in diameter or less were removed from eight of the trees, which were kept free of fruit for 15 months. In July, 4 months after fruit removal, fibrous root (<2 mm d) mass density of defruited trees was 51% greater and insoluble starch in fibrous roots was 24% less than on control trees with fruit. Female T. semipenetrans per gram of root were 64% more numerous on roots of control trees than on defruited trees at this time. Numbers of female nematodes per tree and of juveniles and males in soil did not differ between treatments 4 months after fruit removal. Root mass density remained higher on defruited than control trees for the remaining 13 months that the trees were studied, while nematode density in soil beneath defruited trees rapidly increased to levels proportionate to the additional root mass density. Nine months after fruit removal (December), starch concentration was 84% higher in roots of defruited trees compared to controls and remained 28% higher than in controls 15 months (May) following fruit removal. Between months 9 and 15 following fruit removal, nematode density in soil beneath defruited trees increased at a rate five times that of nematode density beneath control trees. In May, female fecundity (eggs/female) on defruited trees was 41% greater than on control trees. The data were consistent with the hypothesis that carbohydrate competition between developing citrus fruit and T. semipenetrans influences seasonal fluctuations in nematode population densities. PMID:19279735

T Tank Farm Interim Surface Barrier Demonstration - Vadose Zone Monitoring FY09 Report

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

Zhang, Z. F.; Strickland, Christopher E.; Field, Jim G.

2010-01-01

DOE’s Office of River Protection constructed a temporary surface barrier over a portion of the T Tank Farm as part of the T Farm Interim Surface Barrier Demonstration Project. As part of the demonstration effort, vadose zone moisture is being monitored to assess the effectiveness of the barrier at reducing soil moisture. A solar-powered system was installed to continuously monitor soil water conditions at four locations (i.e., instrument Nests A, B, C, and D) beneath the barrier and outside the barrier footprint as well as site meteorological conditions. Nest A is placed in the area outside the barrier footprint andmore » serves as a control, providing subsurface conditions outside the influence of the surface barrier. Nest B provides subsurface measurements to assess surface-barrier edge effects. Nests C and D are used to assess changes in soil-moisture conditions beneath the interim surface barrier. Each instrument nest is composed of a capacitance probe (CP) with multiple sensors, multiple heat-dissipation units (HDUs), and a neutron probe (NP) access tube. The monitoring results in FY09 are summarized below. The solar panels functioned normally and could provide sufficient power to the instruments. The CP in Nest C after September 20, 2009, was not functional. The CP sensors in Nest B after July 13 and the 0.9-m CP sensor in Nest D before June 10 gave noisy data. Other CPs were functional normally. All the HDUs were functional normally but some pressure-head values measured by HDUs were greater than the upper measurement-limit. The higher-than-upper-limit values might be due to the very wet soil condition and/or measurement error but do not imply the malfunction of the sensors. Similar to FY07 and FY08, in FY09, the soil under natural conditions (Nest A) was generally recharged during the winter period (October-March) and discharged during the summer period (April-September). Soil water conditions above about 1.5-m to 2-m depth from all three types of measurements (i.e., CP, NP and HDU) showed relatively large variation during the seasonal wetting-drying cycle. For the soil below 2-m depth, the seasonal variation of soil water content was relatively small. The construction of the surface barrier was completed in April 2008. In the soil below the surface barrier (Nests C and D), the CP measurements showed that water content at the soil between 0.6-m and 2.3-m depths was very stable, indicating no climatic impacts on soil water condition beneath the barrier. The NP-measured water content showed that soil water drainage seemed occurring in the soil between about 3.4 m (11 ft) and 9.1 m (30 ft) in FY09. The HDU-measured water pressure decreased consistently in the soil above 5-m depth, indicating soil water drainage at these depths of the soil. In the soil below the edge of the surface barrier (Nest B), the CP-measured water content was relatively stable through the year except at the 0.9-m depth; the NP-measured water content showed that soil water drainage was occurring in the soil between about 3.4 m (11 ft) and 9.1 m (30 ft) but at a slightly smaller magnitude than those in Nests C and D; the HDU-measurements show that the pressure head changes in FY09 in Nest B were less than those for C and D but more than those for A. The soil-water-pressure head was more sensitive to soil water regime changes under dry conditions. In the soil beneath the barrier, the theoretical steady-state values of pressure head is equal to the negative of the distance to groundwater table. Hence, it is expected that, in the future, while the water content become stable, the pressure head will keep decreasing for a long time (e.g., many years). These results indicate that the T Tank Farm surface barrier was performing as expected by intercepting the meteoric water from infiltrating into the soil and the soil was becoming drier gradually. The barrier also has some effects on the soil below the barrier edge but at a reduced magnitude.« less

Shallow ground-water quality beneath cropland in the Red River of the North Basin, Minnesota and North Dakota, 1993-95

USGS Publications Warehouse

Cowdery, Timothy K.

1997-01-01

Land-use factors that increased nitrate and herbicide concentrations were greater tilled area, chemical application, irrigation, and cropland contiguity. Hydrogeological factors that increased these concentrations were a deeper watertable (higher oxygen concentration and less organic carbon), larger grain-size and degree of sorting of aquifer material (shorter time in the soil zone and aquifer), and fewer sulfur-containing minerals (lignite and pyrite) composing the aquifer. High rainfall, just before sampling of the Sheyenne Delta aquifer, contributed to the relatively low nitrate and pesticide concentrations in the shallow ground water of this aquifer by raising the water table higher into the soil zone, increasing ponded water (increasing biodegradation), preventing some chemical application (flooded fields), and leaching and then displacing nitrate-rich water downward, beneath new recharge. The shallow ground-water quality measured beneath cropland in these land-use study areas covers a large range. The land-use, hydrogeological, and rainfall factors controlling this quality also control shallow ground-water quality in other surficial aquifers in the Red River of the North Basin. Although not used for drinking water, 43% of the shallow ground water from the Otter Tail outwash aquifer was above the U.S. Environmental Protection Agency's nitrate maximum contaminant level of 10 mg/L-N, reducing its potential uses. These high nitrate concentrations do not threaten the Otter Tail outwash aquifer's surface-water bodies with eutrophication however, because significant denitrification occurs beneath riparian wetlands before ground water discharges to surface waters.

Long-term effects of silviculture on soil carbon storage: does vegetation control make a difference?

Treesearch

Robert F. Powers; Matt D. Busse; Karis J. McFarlane; Jianwei Zhang; David H. Young

2012-01-01

Forests and the soils beneath them are Earth’s largest terrestrial sinks for atmospheric carbon (C) and healthy forests provide a partial check against atmospheric rises in CO2. Consequently, there is global interest in crediting forest managers who enhance C retention. Interest centres on C acquisition and storage in trees. Less is directed to...

Soil pH and extractable sulfate-sulfur distribution as influenced by tree species and distance from the stem. [Acer rubrum; Quercus coccinea

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

Wolfe, M.H.; Kelly, J.M.; Wolt, J.D.

Stemflow influence on the distribution of soil (NaH/sub 2/PO/sub 4/ extractable) SO/sub 4/-S and pH was evaluated as a function of tree size class and distance from the stem for red maple (Acer rubrum L.) and scarlet oak (Quercus coccinea Muenchh.) at two locations in Tennessee which have received different historical inputs of S from atmospheric sources. Soil profiles around the base of each study tree were sampled by horizon at 25, 50, 100, and 200 cm from the stem along four transects radiating from the stem at 90/sup 0/ angles. Distance from the stem influenced soil pH of Amore » horizons at 25 cm from the stem of red maple and scarlet oak at both sites. Species had an effect on Bt2 and Bt3 soil SO/sub 4/-S concentrations. The Bt2 (0.49 cmol kg/sup -1/) and Bt3 (0.67 cmol kg/sup -1/) horizons beneath scarlet oaks had greater SO/sub 4/-S concentrations than corresponding horizons beneath red maple (0.29 and 0.43 cmol kg/sup -1/, respectively). The results of this study indicate that increased sampling intensity combined with tracer studies will be need to clearly determine the effect of stemflow, tree species, and tree size on subtlety-manifested soil properties such as pH and SO/sub 4/-S as well as other elements of interest.« less

Groundwater recharge in desert playas: current rates and future effects of climate change

NASA Astrophysics Data System (ADS)

McKenna, Owen P.; Sala, Osvaldo E.

2018-01-01

Our results from playas, which are topographic low areas situated in closed-catchments in drylands, indicated that projected climate change in Southwestern USA would have a net positive impact over runon and groundwater recharge beneath playas. Expected increased precipitation variability can cause up to a 300% increase in annual groundwater recharge beneath playas. This increase will overshadow the effect of decreased precipitation amount that could cause up to a 50% decrease in recharge beneath playas. These changes could have a significant impact on groundwater and carbon storage. These results are important given that groundwater resources in Southwestern USA continue to decline due to human consumption outpacing natural recharge of aquifers. Here, we report on groundwater recharge rates ranging from less than 1 mm to greater than 25 mm per year beneath desert playas. Playas located in larger and steeper catchments with finer-textured soils had the highest rates of recharge. Vegetation cover had no effect on recharge beneath playas. We modeled catchment runoff generation and found that the amount of runon a playa receives annually strongly correlated to the rate of groundwater recharge beneath that playa. Runon occurred during precipitation events larger than 20 mm and increased linearly with events above that threshold.

Soil microbial community response to precipitation change in a semi-arid ecosystem

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

Cregger, Melissa; Schadt, Christopher Warren; McDowell, Nathan

2012-01-01

Microbial communities regulate many belowground carbon cycling processes; thus, the impact of climate change on the struc- ture and function of soil microbial communities could, in turn, impact the release or storage of carbon in soils. Here we used a large-scale precipitation manipulation ( 18%, 50%, or ambient) in a pi on-juniper woodland (Pinus edulis-Juniperus mono- sperma) to investigate how changes in precipitation amounts altered soil microbial communities as well as what role seasonal variation in rainfall and plant composition played in the microbial community response. Seasonal variability in precipitation had a larger role in determining the composition of soilmore » microbial communities in 2008 than the direct effect of the experimental precipitation treatments. Bacterial and fungal communities in the dry, relatively moisture-limited premonsoon season were compositionally distinct from communities in the monsoon season, when soil moisture levels and periodicity varied more widely across treatments. Fungal abundance in the drought plots during the dry premonsoon season was particularly low and was 4.7 times greater upon soil wet-up in the monsoon season, suggesting that soil fungi were water limited in the driest plots, which may result in a decrease in fungal degradation of carbon substrates. Additionally, we found that both bacterial and fungal communities beneath pi on pine and juniper were distinct, suggesting that microbial functions beneath these trees are different. We conclude that predicting the response of microbial communities to climate change is highly dependent on seasonal dynam- ics, background climatic variability, and the composition of the associated aboveground community.« less

Detail of plaque beneath column on the south parapet at ...

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

Detail of plaque beneath column on the south parapet at the west end of the bridge. The plaque reads “1914; Mayor E.J. Drussel; Councilmen E.S. Henry, E.F. Hogan, R.P. Lamdin, C.F. Ross, J.H. Shuppert; Leonard & Day, Engineers; C.H. Gildersleeve, Builder.” - First Street Bridge, Spanning Napa River at First Street between Soscol Avenue & Juarez Street, Napa, Napa County, CA

ScienceCast 173: Mud Matters

NASA Image and Video Library

2015-02-05

NASA has launched SMAP, a new satellite to study water, not in oceans or lakes but in the soil beneath our feet. This often overlooked repository of water can have big effects on weather, climate, drought and agriculture.

In situ silicone tube microextraction: a new method for undisturbed sampling of root-exuded thiophenes from marigold (Tagetes erecta L.) in soil.

PubMed

Mohney, Brian K; Matz, Tricia; Lamoreaux, Jessica; Wilcox, David S; Gimsing, Anne Louise; Mayer, Philipp; Weidenhamer, Jeffrey D

2009-11-01

The difficulties of monitoring allelochemical concentrations in soil and their dynamics over time have been a major barrier to testing hypotheses of allelopathic effects. Here, we evaluate three diffusive sampling strategies that employ polydimethylsiloxane (PDMS) sorbents to map the spatial distribution and temporal dynamics of root-exuded thiophenes from the African marigold, Tagetes erecta. Solid phase root zone extraction (SPRE) probes constructed by inserting stainless steel wire into PDMS tubing were used to monitor thiophene concentrations at various depths beneath marigolds growing in PVC pipes. PDMS sheets were used to map the distribution of thiophenes beneath marigolds grown in thin glass boxes. Concentrations of the two major marigold thiophenes measured by these two methods were extremely variable in both space and time. Dissection and analysis of roots indicated that distribution of thiophenes in marigold roots also was quite variable. A third approach used 1 m lengths of PDMS microtubing placed in marigold soil for repeated sampling of soil without disturbance of the roots. The two ends of the tubing remained out of the soil so that solvent could be washed through the tubing to collect samples for HPLC analysis. Unlike the other two methods, initial experiments with this approach show more uniformity of response, and suggest that soil concentrations of marigold thiophenes are affected greatly even by minimal disturbance of the soil. Silicone tube microextraction gave a linear response for alpha-terthienyl when maintained in soils spiked with 0-10 ppm of this thiophene. This method, which is experimentally simple and uses inexpensive materials, should be broadly applicable to the measurement of non-polar root exudates, and thus provides a means to test hypotheses about the role of root exudates in plant-plant and other interactions.

Aeolian cliff-top deposits and buried soils in the White River Badlands, South Dakota, USA

USGS Publications Warehouse

Rawling, J. E.; Fredlund, G.G.; Mahan, S.

2003-01-01

Aeolian deposits in the North American Great Plains are important sources of Holocene palaeo-environmental records. Although there are extensive studies on loess and dune records in the region, little is known about records in aeolian cliff-top deposits. These are common on table (mesa) edges in the White River Badlands. These sediments typically have loam and sandy-loam textures with dominantly very fine sand, 0.5-1% organic carbon and 0.5-5% CaCO3. Some of these aeolian deposits are atypically coarse and contain granules and fine pebbles. Buried soils within these deposits are weakly developed with A-C and A-AC-C profiles. Beneath these are buried soils with varying degrees of pedogenic development formed in fluvial, aeolian or colluvial deposits. Thickness and number of buried soils vary. However, late-Holocene soils from several localities have ages of approximately 1300, 2500 and 3700 14C yrs BP. The 1300 14C yr BP soil is cumulic, with a thicker and lighter A horizon. Soils beneath the cliff-top deposits are early-Holocene (typically 7900 but as old as 10000 14C yrs BP) at higher elevation (???950 m) tables, and late-Holocene (2900 14C yrs BP) at lower (???830 m) tables. These age estimates are based on total organic matter 14C ages from the top 5 cm of buried soils, and agreement is good between an infrared stimulated luminescence age and bracketing 14C ages. Our studies show that cliff-top aeolian deposits have a history similar to that of other aeolian deposits on the Great Plains, and they are another source of palaeoenvironmental data.

Treeline biogeochemistry and dynamics, Noatak National Preserve, northwestern Alaska: A section in Studies by the U.S. Geological Survey in Alaska, 2000

USGS Publications Warehouse

Stottlemyer, Robert; Binkley, Dan; Steltzer, Heidi; Wilson, Frederic H.; Galloway, John P.

2002-01-01

The extensive boreal biome is little studies relative to its global importance. Its high soil moisture and low temperatures result in large below-ground reservoirs of carbon (C) and nitrogen (N). Presently, such high-latitude ecosystems are undergoing the largest temperature increases in global warming. Change in soil temperature or moisture in the large pools of soil organic matter could fundamentally change ecosystem C and N budgets. Since 1990, we have conducted treeline studies in a small (800 ha) watershed in Noatak National Preserve, northwestern Alaska. Our objectives were to (1) gain an understanding of treeline dynamics, structure, and function; and (2) examine the effects of global climate change, particularly soil temperature, moisture, and N availability, on ecosystem processes. Our intensive site studies show that the treeline has advanced into turdra during the past 150 years. Inplace and laboratory incubations indicate that soil organic-layer mineralization rates increase with a temperature change >5 degrees C. N availability was greatest in soils beneath alder and lowest beneath willow or cottongrass tussocks. Watershed output of inorganic N as NO3 was 70 percent greater than input. The high inorganic-N output likely reflects soil freeze-thaw cycles, shallow flowpaths to the stream, and low seasonal biological retention. Concentrations and flux of dissolved organic carbon (DOC) in streamwater increased during spring melt and in autumn, indicating a seasonal accumulation of soil and forest-floor DOC and a shallower flowpath for meltwater to the stream. In sum, our research suggests that treeling transitionzone processes are quite sensitive to climate change, especially those functions regulating the C and N cycles.

Impact of Residential Prairie Gardens on the Physical Properties of Urban Soil in Madison, Wisconsin.

PubMed

Johnston, Marie R; Balster, Nick J; Zhu, Jun

2016-01-01

Prairie gardens have become a common addition to residential communities in the midwestern United States because prairie vegetation is native to the region, requires fewer resources to maintain than turfgrass, and has been promoted to help remediate urban soil. Although prairie systems typically have deeper and more diverse root systems than traditional turfgrass, no one has tested the effect of this vegetation type on the physical properties of urban soil. We hypothesized that residential prairie gardens would yield lower soil bulk density (BD), lower penetration resistance (PR), greater soil organic matter (SOM), and greater saturated hydraulic conductivity () compared with turfgrass lawns. To test this hypothesis, we examined 12 residential properties in Madison, WI, where homeowners had established a prairie garden within their turfgrass lawn. Despite a consistent trend in the difference between vegetation types, no significant main effects were found (i.e., a difference between vegetation types when averaged over depth) for any of the four soil properties measured in this study. Differences were found with depth and depended on a significant interaction with vegetation type. At the surface depth (0-0.15 m), soil beneath prairie gardens had 10% lower mean BD, 15% lower mean PR, 25% greater level of SOM, and 33% greater compared with soil beneath the adjacent lawns. These differences were not detected at deeper sampling intervals of 0.15 to 0.30 m and 0.30 to 0.45 m. Although not statistically significant, the consistent trend and direction among soil variables suggest that residential prairie gardens had changed the surface soil at a rate that marginally outpaced turfgrass and calls for controlled experiments to identify the mechanisms that might enhance these trends. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Forest canopy structural controls over throughfall affect soil microbial community structure in an epiphyte-laden maritime oak stand

NASA Astrophysics Data System (ADS)

Van Stan, J. T., II; Rosier, C. L.; Schrom, J. O.; Wu, T.; Reichard, J. S.; Kan, J.

2014-12-01

Identifying spatiotemporal influences on soil microbial community (SMC) structure is critical to understanding of patterns in nutrient cycling and related ecological services. Since forest canopy structure alters the spatiotemporal patterning of precipitation water and solute supplies to soils (via the "throughfall" mechanism), is it possible changes in SMC structure variability could arise from modifications in canopy elements? Our study investigates this question by monitoring throughfall water and dissolved ion supply to soils beneath a continuum of canopy structure: from a large gap (0% cover) to heavy Tillandsia usneoides L. (Spanish moss) canopy (>90% cover). Throughfall water supply diminished with increasing canopy cover, yet increased washoff/leaching of Na+, Cl-, PO43-, and SO42- from the canopy to the soils (p < 0.01). Presence of T. usneoides diminished throughfall NO3-, but enhanced NH4+, concentrations supplied to subcanopy soils. The mineral soil horizon (0-10 cm) from canopy gaps, bare canopy, and T. usneoides-laden canopy significantly differed (p < 0.05) in soil chemistry parameters (pH, Ca2+, Mg2+, CEC). PCR-DGGE banding patterns beneath similar canopy covers (experiencing similar throughfall dynamics) also produced high similarities per ANalyses Of SIMilarity (ANO-SIM), and clustered together when analyzed by Nonmetric Multidimensional Scaling (NMDS). Correlation analysis of DGGE banding patterns, throughfall dynamics, and soil chemistry yielded significant correlations (p < 0.05) between fungal communities and soil chemical properties significantly differing between canopy cover types (pH: r2 = 0.50; H+ %-base saturation: r2 = 0.48; Ca2+ %-base saturation: r2 = 0.43). Bacterial community structure correlated with throughfall NO3-, NH4+, and Ca2+ concentrations (r2 = 0.37, p = 0.16). These results suggest that modifications of forest canopy structures are capable of affecting mineral-soil horizon SMC structure via the throughfall mechanism when canopies' biomass distribution is highly heterogeneous.

Plant-based plume-scale mapping of tritium contamination in desert soils

USGS Publications Warehouse

Andraski, Brian J.; Stonestrom, David A.; Michel, R.L.; Halford, K.J.; Radyk, J.C.

2005-01-01

Plant-based techniques were tested for field-scale evaluation of tritium contamination adjacent to a low-level radioactive waste (LLRW) facility in the Amargosa Desert, Nevada. Objectives were to (i) characterize and map the spatial variability of tritium in plant water, (ii) develop empirical relations to predict and map subsurface contamination from plant-water concentrations, and (iii) gain insight into tritium migration pathways and processes. Plant sampling [creosote bush, Larrea tridentata (Sessé & Moc. ex DC.) Coville] required one-fifth the time of soil water vapor sampling. Plant concentrations were spatially correlated to a separation distance of 380 m; measurement uncertainty accounted for <0.1% of the total variability in the data. Regression equations based on plant tritium explained 96 and 90% of the variation in root-zone and sub-root-zone soil water vapor concentrations, respectively. The equations were combined with kriged plant-water concentrations to map subsurface contamination. Mapping showed preferential lateral movement of tritium through a dry, coarse-textured layer beneath the root zone, with concurrent upward movement through the root zone. Analysis of subsurface fluxes along a transect perpendicular to the LLRW facility showed that upward diffusive-vapor transport dominates other transport modes beneath native vegetation. Downward advective-liquid transport dominates at one endpoint of the transect, beneath a devegetated road immediately adjacent to the facility. To our knowledge, this study is the first to document large-scale subsurface vapor-phase tritium migration from a LLRW facility. Plant-based methods provide a noninvasive, cost-effective approach to mapping subsurface tritium migration in desert areas.

Recovery of a soil degraded by deep excavation using plantation of tree species and a cellulose by-product as amendment

NASA Astrophysics Data System (ADS)

Guimarães Giácomo, Rômulo; Alves, Marlene Cristina; Paz-Ferreiro, Jorge

2014-05-01

Organic by-products obtained from the cellulose industry have been used as costs effective fertilizers in agricultural and forest soils and also as amendments for recovery of abandoned land. The construction of a power plant in the Paraná River (Brazil) motivates the deep excavation of a soil profile under native forest. Once exposed, the saprolite beneath the natural soil was abandoned, without any reclamation measure. The land left after engineering works was a harsh environment, where secondary vegetation hardly or not at all recovered. The objective of this study was to tests the efficiency of recycling a composted product obtained from cellulose waste to reclaim the abandoned saprolite material. A field trial was carried out following a classical split-split plot experimental design. In this design plantations plantations of Eucalyptus urograndis (a hybrid Eucalyptus species, considered here as exotic) and Mabea fistulifera (a native species) were the main plots. Within each main plot, subplots were six fertilizer treatments including an external control treatment, without any intervention, a control treatment, without fertilization, a mineral fertilizer treatment and three treatments amended with compost from cellulose applied at the rates of 10, 15 and 20 Mg ha-1. There were four replications per treatment. The recovery of the soil profile under the different treatments studied was assessed by indices obtained from analysis of soil physical and chemical properties. Variables such as tree species development, litter and plant debris fall, return of nutrients from vegetation to soil and epigeal fauna were also characterized. Increasing dose of amendment with cellulose by-product showed a trend to improve water infiltration and soil resistance to penetration. Treatment with 20 Mg ha-1of cellulose compost showed the highest nutrient availability, but also exhibited an important increase in soil pH. The greatest development of planted trees was recorded in the treatment with mineral fertilization, whereas a dose of 10 Mg ha-1 of amendment by cellulose by-product was the most promising for tree growth. Return of litter, plant debris and nutrients to the soil and epigeal fauna increased with increasing as the dose of the cellulose by-product increased.

Throughfall-mediated alterations to soil microbial community structure in a forest plot of homogenous soil texture, litter, and plant species composition

NASA Astrophysics Data System (ADS)

Van Stan, John; Rosier, Carl; Moore, Leslie; Gay, Trent; Reichard, James; Wu, Tiehang; Kan, Jinjun

2015-04-01

Identifying spatiotemporal influences on soil microbial community (SMC) structure is critical to our understanding of patterns in biogeochemical cycling and related ecological services (e.g., plant community structure, water quality, response to environmental change). Since forest canopy structure alters the spatiotemporal patterning of precipitation water and solute supplies to soils (via "throughfall"), is it possible that changes in SMC structure could arise from modifications in canopy elements? Our study investigates this question by monitoring throughfall water and dissolved ion supply to soils beneath a continuum of canopy structure: from large gaps (0% cover), to bare Quercus virginiana Mill. (southern live oak) canopy (~50-70%), to heavy Tillandsia usneoides L. (Spanish moss) canopy (>90% cover). Throughfall water supply diminished with increasing canopy cover, yet increased washoff/leaching of Na+, Cl-, PO43-, and SO42- from the canopy to the soils. Presence of T. usneoides diminished throughfall NO3-, but enhanced NH4+, concentrations supplied to subcanopy soils. The mineral soil horizon (0-10 cm) sampled in triplicate from locations receiving throughfall water and solutes from canopy gaps, bare canopy, and T. usneoides-laden canopy significantly differed in soil chemistry parameters (pH, Ca2+, Mg2+, CEC). Polymerase Chain Reaction-Denaturant Gradient Gel Electrophoresis (PCR-DGGE) banding patterns beneath similar canopy covers (experiencing similar throughfall dynamics) also produced high similarities per ANalyses Of SIMilarity (ANO-SIM), and clustered together when analyzed by Nonmetric Multidimensional Scaling (NMDS). These results suggest that modifications of forest canopy structures are capable of affecting mineral-soil horizon SMC structure via throughfall when canopies' biomass distribution is highly heterogeneous. As SMC structure, in many instances, relates to functional diversity, we suggest that future research seek to identify functional diversity shifts (e.g., nitrogen transformation) in response to canopy structural alterations of throughfall water/solute concentration

Evaluating the Impacts of Grassland Conversions to Experimental Forest on Groundwater Recharge in the Nebraska Sand Hills

NASA Astrophysics Data System (ADS)

Adane, Zablon A.

The Nebraska Sand Hills grasslands provide the greatest groundwater recharge rates in the High Plains Aquifer. However, the grasslands and their ecological services have become vulnerable to land use change and degradation. This study used a series of field data to investigate the effects of grassland conversions to forest on recharge rates in a century-old experimental forest in the Sand Hills. The results show that the impact of grassland conversion on recharge was dependent on the species and plantation density. Estimated recharge rates beneath the dense plantations represent reductions of 86-94% relative to the native grassland. Results of 1H Nuclear Magnetic Resonance spectral analysis suggested that the surface soil organic carbon beneath pine plantations also contain up to 3 times the ratio of hydrophobic components than the native grasslands and may alter the soil hydraulic properties. This investigation further uncovered a previously overlooked feedback between the effect of soil organic carbon chemical shift generated by the ponderosa pine needle litter decomposition; namely that the alteration may have a link to reduced groundwater recharge rates. Thus, a global optimizer algorithm was used to estimate the effective soil hydraulic parameters from monthly soil moisture contents and recharge rates were then estimated through HYDRUS 1-D numerical modeling for grassland and pine forest soils. The impact of grassland conversion to pine was an overall reduction of groundwater recharge by nearly 100%. These outcomes highlight the significance of the grasslands for recharge, in the Sand Hills and the sustainability of the High Plains Aquifer.

Ecological longevity of Polaskia chende (Cactaceae) seeds in the soil seed bank, seedling emergence and survival.

PubMed

Ordoñez-Salanueva, C A; Orozco-Segovia, A; Canales-Martínez, M; Seal, C E; Pritchard, H W; Flores-Ortiz, C M

2017-11-01

Soil seed banks are essential elements of plant population dynamics, enabling species to maintain genetic variability, withstand periods of adversity and persist over time, including for cactus species. However knowledge of the soil seed bank in cacti is scanty. In this study, over a 5-year period we studied the seed bank dynamics, seedling emergence and nurse plant facilitation of Polaskia chende, an endemic columnar cactus of central Mexico. P. chende seeds were collected for a wild population in Puebla, Mexico. Freshly collected seeds were sown at 25 °C and 12-h photoperiod under white light, far-red light and darkness. The collected seeds were divided in two lots, the first was stored in the laboratory and the second was use to bury seeds in open areas and beneath a shrub canopy. Seeds were exhumed periodically over 5 years. At the same time seeds were sown in open areas and beneath shrub canopies; seedling emergence and survival were recorded over different periods of time for 5 years. The species forms long-term persistent soil seed banks. The timing of seedling emergence via germination in the field was regulated by interaction between light, temperature and soil moisture. Seeds entered secondary dormancy at specific times according to the expression of environmental factors, demonstrating irregular dormancy cycling. Seedling survival of P. chende was improved under Acacia constricta nurse plants. Finally, plant facilitation affected the soil seed bank dynamics as it promoted the formation of a soil seed bank, but not its persistence. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

142 E Ontario, October 2014, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

During removal of granite tiles at the store front it was discovered that an existing foundation was present and appeared to be adequate to support the planned renovations. No disturbance of fill soil beneath the sidewalk area was necessary.

Phoenix La Mancha Trench in 3-D

NASA Image and Video Library

2008-10-09

This anaglyph was taken by NASA Phoenix Mars Lander Surface Stereo Imager Oct. 7, 2008. The anaglyph highlights the depth of the trench, informally named La Mancha, and reveals the ice layer beneath the soil surface. 3D glasses are necessary.

Nutrients in groundwaters of the conterminous United States, 1992-1995

USGS Publications Warehouse

Nolan, B.T.; Stoner, J.D.

2000-01-01

Results of a national water quality assessment indicate that nitrate is detected in 71% of groundwater samples, more than 13 times as often as ammonia, nitrite, organic nitrogen, and orthophosphate, based on a common detection threshold of 0.2 mg/L. Shallow groundwater (typically 5 m deep or less) beneath agricultural land has the highest median nitrate concentration (3.4 mg/L), followed by shallow groundwater beneath urban land (1.6 mg/L) and deeper groundwater in major aquifers (0.48 mg/L). Nitrate exceeds the maximum contaminant level, 10 mg/L as nitrogen, in more than 15% of groundwater samples from 4 of 33 major aquifers commonly used as a source of drinking water. Nitrate concentration in groundwater is variable and depends on interactions among several factors, including nitrogen loading, soil type, aquifer permeability, recharge rate, and climate. For a given nitrogen loading, factors that generally increase nitrate concentration in groundwater include well-drained soils, fractured bedrock, and irrigation. Factors that mitigate nitrate contamination of groundwater include poorly drained soils, greater depth to groundwater, artificial drainage systems, intervening layers of unfractured bedrock, a low rate of groundwater recharge, and anaerobic conditions in aquifers.

The yeast flora of the coast redwood, Sequoia sempervirens.

PubMed

Middelhoven, W J

2003-01-01

Only four yeast species could be isolated from young and perannual shoots of the coast redwood tree, Sequoia sempervirens, and from soil beneath the trees, viz. both varieties of Debaryomyces hansenii, Trichosporon pullulans, T. porosum and an unidentified red basidiomycetous yeast.

Geophysical methods

USDA-ARS?s Scientific Manuscript database

Near-surface geophysical methods have become have become important tools for agriculture. Geophysics employed for agriculture tends to be heavily focused on a 2 m zone directly beneath the ground surface, which includes the crop root zone and all, or at least most, of the soil profile. Resistivity...

Modification of Roberts' Theory for Rocket Exhaust Plumes Eroding Lunar Soil

NASA Technical Reports Server (NTRS)

Metzger, Philip T.; Lane, John E.; Immer, Christopher D.

2008-01-01

Roberts' model of lunar soil erosion beneath a landing rocket has been updated in several ways to predict the effects of future lunar landings. The model predicts, among other things, the number of divots that would result on surrounding hardware due to the impact of high velocity particulates, the amount and depth of surface material removed, the volume of ejected soil, its velocity, and the distance the particles travel on the Moon. The results are compared against measured results from the Apollo program and predictions are made for mitigating the spray around a future lunar outpost.

Utilization of humus-rich forest soil (mull) in geochemical exploration for gold

USGS Publications Warehouse

Curtin, Gary C.; Lakin, H.W.; Neuerburg, G.J.; Hubert, A.E.

1968-01-01

Distribution of gold in humus-rich forest soil (mull) reflects the known distribution of gold deposits in bedrock in the Empire district, Colorado. Gold from the bedrock is accumulated by pine and aspen trees and is concentrated in the mull by the decay of organic litter from the trees. Anomalies in mull which do not coincide with known gold deposits merit further exploration. The gold anomalies in soil (6- to 12-inch depth) and in float pebbles and cobbles poorly reflect the known distribution of gold deposits in bedrock beneath the extensive cover of colluvium and glacial drift.

KSC-07pd1381

NASA Image and Video Library

2007-06-05

KENNEDY SPACE CENTER, FLA. -- At the Payload Hazardous Servicing Facility, workers integrate the landing radar with the Phoenix spacecraft. Testing will follow. The Phoenix mission is the first project in NASA's first openly competed program of Mars Scout missions. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/George Shelton

KSC-07pd2176

NASA Image and Video Library

2007-08-04

KENNEDY SPACE CENTER, FLA. - NASA's Phoenix spacecraft begins its journey to Mars aboard a Delta II 7925 rocket at 5:26 a.m. EDT from Pad 17A at Cape Canaveral Air Force Station. Phoenix will land in icy soils near the north polar, permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Tony Gray and Robert Murray

KSC-07pd1910

NASA Image and Video Library

2007-07-17

KENNEDY SPACE CENTER, Fla. -- In the Payload Hazardous Servicing Facility, workers secure the Phoenix Mars Lander spacecraft onto the upper stage booster. Targeted for launch from Cape Canaveral Air Force Station on Aug. 3, Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. NASA/Dimitri Gerondidakis

KSC-07pd1383

NASA Image and Video Library

2007-06-05

KENNEDY SPACE CENTER, FLA. -- A closeup of the landing radar installed on the Phoenix spacecraft. Testing will follow. The Phoenix mission is the first project in NASA's first openly competed program of Mars Scout missions. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/George Shelton

KSC-07pd1382

NASA Image and Video Library

2007-06-05

KENNEDY SPACE CENTER, FLA. -- At the Payload Hazardous Servicing Facility, workers integrate the landing radar with the Phoenix spacecraft. Testing will follow. The Phoenix mission is the first project in NASA's first openly competed program of Mars Scout missions. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/George Shelton

KSC-07pd2178

NASA Image and Video Library

2007-08-04

KENNEDY SPACE CENTER, FLA. - The Delta II 7925 rocket carrying NASA's Phoenix Mars lander roars off Pad 17A on Cape Canaveral Air Force Station at 5:26 a.m. EDT. Phoenix will land in icy soils near the north polar, permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Sandra Joseph and John Kechele

KSC-07pd2015

NASA Image and Video Library

2007-07-19

KENNEDY SPACE CENTER, Fla. -- In the Payload Hazardous Servicing Facility, the Phoenix Mars Lander spacecraft rests with its heat shield installed. Targeted for launch from Cape Canaveral Air Force Station on Aug. 3, Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Troy Cryder

KSC-07pd2011

NASA Image and Video Library

2007-07-19

KENNEDY SPACE CENTER, Fla. --In the Payload Hazardous Servicing Facility, the heat shield for the Phoenix Mars Lander spacecraft is moved toward the spacecraft. Targeted for launch from Cape Canaveral Air Force Station on Aug. 3, Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Troy Cryder

KSC-07pd2012

NASA Image and Video Library

2007-07-19

KENNEDY SPACE CENTER, Fla. -- In the Payload Hazardous Servicing Facility, the heat shield for the Phoenix Mars Lander spacecraft is lowered onto the spacecraft. Targeted for launch from Cape Canaveral Air Force Station on Aug. 3, Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Troy Cryder

KSC-07pd2171

NASA Image and Video Library

2007-08-04

KENNEDY SPACE CENTER, FLA. - NASA's Phoenix Mars lander lifts off from Pad 17A aboard a Delta II 7925 rocket at Cape Canaveral Air Force Station at 5:26 a.m. EDT. Phoenix will land in icy soils near the north polar, permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Regina Mitchell-Ryall and Jerry Cannon

KSC-07pd2170

NASA Image and Video Library

2007-08-04

KENNEDY SPACE CENTER, FLA. -- The Delta II 7925 rocket carrying NASA's Phoenix Mars lander lifts off amid billows of smoke from Pad 17A at Cape Canaveral Air Force Station at 5:26 a.m. EDT. Phoenix will land in icy soils near the north polar, permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/George Shelton

KSC-07pd2177

NASA Image and Video Library

2007-08-04

KENNEDY SPACE CENTER, FLA. - The Delta II 7925 rocket carrying NASA's Phoenix Mars lander thunders to life at 5:26 a.m. EDT at Pad 17A on Cape Canaveral Air Force Station. Phoenix will land in icy soils near the north polar, permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Sandra Joseph and John Kechele

KSC-07pd1380

NASA Image and Video Library

2007-06-05

KENNEDY SPACE CENTER, FLA. -- At the Payload Hazardous Servicing Facility, workers integrate the landing radar with the Phoenix spacecraft. Testing will follow. The Phoenix mission is the first project in NASA's first openly competed program of Mars Scout missions. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/George Shelton

KSC-07pd1647

NASA Image and Video Library

2007-06-26

KENNEDY SPACE CENTER, FLA. -- The Phoenix Mars Lander is on display in the Payload Hazardous Servicing Facility. Phoenix is scheduled to launch Aug. 3 from Launch Pad 17-A at Cape Canaveral Air Force Station. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Kim Shiflett

KSC-07pd2005

NASA Image and Video Library

2007-07-19

KENNEDY SPACE CENTER, Fla. -- In the Payload Hazardous Servicing Facility, the heat shield (foreground) for the Phoenix Mars Lander spacecraft is ready for installation. Targeted for launch from Cape Canaveral Air Force Station on Aug. 3, Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Troy Cryder

KSC-07pd1648

NASA Image and Video Library

2007-06-26

KENNEDY SPACE CENTER, FLA. -- A closeup of the Phoenix Mars Lander on display in the Payload Hazardous Servicing Facility. Phoenix is scheduled to launch Aug. 3 from Launch Pad 17-A at Cape Canaveral Air Force Station. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Kim Shiflett

KSC-07pd2013

NASA Image and Video Library

2007-07-19

KENNEDY SPACE CENTER, Fla. -- In the Payload Hazardous Servicing Facility, workers guide the heat shield onto the Phoenix Mars Lander spacecraft. Targeted for launch from Cape Canaveral Air Force Station on Aug. 3, Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Troy Cryder

KSC-07pd1901

NASA Image and Video Library

2007-07-17

KENNEDY SPACE CENTER, Fla. -- In the Payload Hazardous Servicing Facility, workers prepare the upper stage booster to be mated to the Phoenix Mars Lander spacecraft. Targeted for launch from Cape Canaveral Air Force Station on Aug. 3, Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. NASA/Dimitri Gerondidakis

KSC-07pd1379

NASA Image and Video Library

2007-06-05

KENNEDY SPACE CENTER, FLA. -- At the Payload Hazardous Servicing Facility, workers integrate the landing radar with the Phoenix spacecraft. Testing will follow. The Phoenix mission is the first project in NASA's first openly competed program of Mars Scout missions. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/George Shelton

KSC-07pd1378

NASA Image and Video Library

2007-06-05

KENNEDY SPACE CENTER, FLA. -- At the Payload Hazardous Servicing Facility, the landing radar is integrated with the Phoenix spacecraft. Testing will follow. The Phoenix mission is the first project in NASA's first openly competed program of Mars Scout missions. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/George Shelton

KSC-07pd1902

NASA Image and Video Library

2007-07-17

KENNEDY SPACE CENTER, Fla. -- In the Payload Hazardous Servicing Facility, workers rotate the Phoenix Mars Lander spacecraft to move it for mating to the upper stage booster. Targeted for launch from Cape Canaveral Air Force Station on Aug. 3, Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. NASA/Dimitri Gerondidakis

KSC-07pd1909

NASA Image and Video Library

2007-07-17

KENNEDY SPACE CENTER, Fla. -- In the Payload Hazardous Servicing Facility, workers attach the Phoenix Mars Lander spacecraft onto the upper stage booster. Targeted for launch from Cape Canaveral Air Force Station on Aug. 3, Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. NASA/Dimitri Gerondidakis

KSC-07pd2014

NASA Image and Video Library

2007-07-19

KENNEDY SPACE CENTER, Fla. -- In the Payload Hazardous Servicing Facility, workers observe the installation of the heat shield onto the Phoenix Mars Lander spacecraft. Targeted for launch from Cape Canaveral Air Force Station on Aug. 3, Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Troy Cryder

KSC-07pd2179

NASA Image and Video Library

2007-08-04

KENNEDY SPACE CENTER, FLA. - The Delta II 7925 rocket carrying NASA's Phoenix Mars lander bounds off Pad 17A on Cape Canaveral Air Force Station at 5:26 a.m. EDT. Phoenix will land in icy soils near the north polar, permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Sandra Joseph and John Kechele

Stable oxygen isotope analysis reveal vegetation influence on soil water movement and ecosystem water fluxes in a semi-arid oak woodland

NASA Astrophysics Data System (ADS)

Piayda, Arndt; Dubbert, Maren; Werner, Christiane; Cuntz, Matthias

2015-04-01

Mechanistically disentangling the role and function of vegetation within the hydrological cycle is one of the key questions in the interdisciplinary field of ecohydrology. The presence of vegetation can have various impacts on soil water relations: transpiration of active vegetation causes great water losses, rainfall is intercepted, soil evaporation can be reduced and infiltration, hydraulic redistribution and translatory flow might be altered. In drylands, covering around 40% of the global land surface, the carbon cycle is closely coupled to water availability due to (seasonal) droughts. Specifically savannah type ecosystems, which cover large areas worldwide, are, due to their bi-layered structure, very suitable to study the effects of distinct vegetation types on the ecosystem water cycle. Oxygen isotope signatures (δ18O) have been used to partition ecosystem evapotranspiration (ET ) because of the distinct isotopic compositions of water transpired by leaves relative to soil evaporated vapor. Recent developments in laser spectroscopy enable measurements of δ18O in the vapor phase with high temporal resolution in the field and bear a novel opportunity to trace water movement within the ecosystem. In the present study, the effects of distinct vegetation layers (i.e. trees and herbaceous vegetation) on soil water infiltration and redistribution as well as ecosystem water fluxes in a Mediterranean cork-oak woodland are disentangled. An irrigation experiment was carried out using δ18O labeled water to quantify the distinct effects of trees and herbaceous vegetation on 1) infiltration and redistribution of water in the soil profile and 2) to disentangle the effects of tree cover on the contribution of unproductive soil evaporation and understory transpiration to total ET . First results proof that stable δ18O isotopes measured onsite with laser spectroscopy is a valuable tool to trace water movement in the soil showing a much higher sensitivity than common TDR-type probes. It was possible to track soil water redistribution even beyond zero net water flux measured with TDR probes. Under shaded conditions beneath tree crowns, infiltration of precipitation reaches much deeper depths due to the limited radiation energy input and thus, reduced evaporative losses, compared to open areas between crowns. As a consequence, the isotopic enrichment back to initial conditions (as observed before the artificial precipitation event) was strongly delayed. Despite the higher water availability beneath tree crowns, transpiration of understory plants and soil evaporation rates were reduced compared to the open area due to the lack of energy. However, transpiration could be maintained much longer and at higher rates after the precipitation event then soil evaporation. These first results support previous findings at this site where a clear difference in understory plant community structure was observed. Beneath tree crowns, favorable water conditions enables a higher occurrence of grasses and nitrogen fixing forbs, whereas in between tree crowns drought adapted native species became dominant.

What Lies Beneath Can Be Imaged

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

Johnson, Tim

The Hanford Site was quickly established to help end World War II, making history for producing the plutonium used in the world’s first nuclear weapons. Throughout the Cold War years, Hanford employees produced plutonium for most of the more than 60,000 weapons in the U.S. nuclear arsenal stockpile. Today, the once highly active nuclear reactors are shut down. And the mission at Hanford turned full-circle as scientists, engineers and specialists work to clean up our nation’s most contaminated nuclear site. PNNL Computational Geophysicist Tim Johnson is helping decision-makers understand the complexity and breadth of the contamination in soils at Hanford.more » Tim and others are applying remote, high-resolution geophysical imaging to determine the extent of contamination in the soil below the surface and understand the processes controlling its movement. They also provide real-time imaging of remediation processes that are working to limit the movement of contaminants below the surface and toward water resources. Geophysical imaging simply means that PNNL scientists are combining the techniques of geology, physics, mathematics and chemistry with supercomputer modeling to create three-dimensional images of the waste and its movement. These real-time, remote images are essential in reducing the uncertainty associated with cleanup costs and remediation technologies.« less

Shallow Ground-Water Flux Beneath a Restored Wetland Using Two-Dimensional Simulation of Ground-Water Flow and Heat Transport

NASA Astrophysics Data System (ADS)

Burow, K. R.; Gamble, J. M.; Fujii, R.; Constantz, J.

2001-12-01

Water flowing through the Sacramento-San Joaquin River Delta supplies drinking water to more than 20 million people in California. Delta water contains elevated concentrations of dissolved organic carbon (DOC) from drainage through the delta peat soils, forming trihalomethanes when the water is chlorinated for drinking. Land subsidence caused by oxidation of the peat soils has led to increased pumping of drainage water from delta islands to maintain arable land. An agricultural field on Twitchell Island was flooded in 1997 to evaluate continuous flooding as a technique to mitigate subsidence. The effects of shallow flooding on DOC loads to the drain water must be determined to evaluate the feasibility of this technique. In this study, heat is used as a nonconservative tracer to determine shallow ground-water flux and calculate DOC loads to an adjacent drainage ditch. Temperature profiles and water levels were measured in 12 wells installed beneath the pond, in the pond, and in an adjacent drainage ditch from May 2000 to June 2001. The range in seasonal temperatures decreased with depth, but seasonal temperature variation was evident in wells screened as deep as 10 to 12 feet below land surface. A constant temperature of 17 degrees C was measured in wells 25 feet beneath the pond. Ground-water flux beneath the pond was quantified in a two-dimensional simulation of water and heat exchange using the SUTRA flow and transport model. The effective vertical hydraulic conductivity of the peat soils underlying the pond was estimated through model calibration. Calibrated hydraulic conductivity is higher (1E-5 m/sec) than estimates from slug tests (2E-6 m/sec). Modeled pond seepage is similar to that estimated from a water budget, although the total seepage determined from the water budget is within the range of error of the instrumentation. Overall, model results indicate that recharge from the pond flows along shallow flow paths and that travel times through the peat to the drainage ditch may be on the order of decades.

Effects of Vegetation Removal and Soil Disturbance on Soil Organic and Inorganic Carbon Dynamics in California Desert Ecosystems

NASA Astrophysics Data System (ADS)

Swanson, A. C.; Allen, E. B.; Allen, M. F.; Hernandez, R. R.

2015-12-01

Solar energy developments are projected to be deployed over desert wildland areas with deep soil inorganic carbon (SIC) deposits, which often involves elimination of deep-rooted vegetation. This land cover change may systemically alter SIC pools since respired CO2 is the carbon (C) source during SIC formation. We sought to understand how removal of creosote bush scrub affects soil C pools. We hypothesized that vegetation is important for maintaining SIC and soil organic C (SOC) pools and that disturbance to the vegetation and soil will change CO2 flux with increased losses from SIC. Soils were collected from sites that had intact creosote bush scrub habitat adjacent to disturbed, bare areas where the native vegetation had been previously removed. Samples were taken from beneath shrub canopies and interspaces in intact areas, and from random points in the disturbed area. Soils were analyzed for SIC, SOC, microbial and labile C, and δ13C. Soils were also incubated to determine the potential CO2 flux from disturbed and undisturbed soils along with the sources of CO2. Three replicates per soil underwent a control and water addition treatment and flux and δ13C of CO2 were measured continuously. Control replicates yielded no significant CO2 flux. CO2 flux from watered soils was higher beneath shrub canopy (18.57µmol g soil-1 day-1±1.86) than the interspace soils (0.86 µmol g soil-1 day-1±0.17). Soils collected from bare areas had an intermediate flux (5.41 µmol g soil-1 day-1±2.68 and 3.68 µmol g soil-1 day-1±0.85, respectively) lying between shrub canopy and interspace soils. There was no significant difference between the δ13C values of CO2 from shrub canopy and interspace soils, both of which had a very low δ13C values (-22.60‰±0.64 and -23.88‰±0.89, respectively), resembling that of organic C. However, the isotopic values of CO2 from disturbed soils were significantly higher (-16.68‰±1.36 and -15.22‰±2.12, respectively) suggesting that these soils effluxed a greater proportion of CO2 from an inorganic source than intact soils. Microbial and labile C were highest under shrub canopy, intermediate in interspaces, and lowest in bare areas. Vegetation removal to accommodate renewable energy developments may negatively impact soil C, potentially leading to unintended increased soil C losses from the SIC pool.

Fate and Transport of 17β-estradiol Beneath Animal Waste Holding Ponds

NASA Astrophysics Data System (ADS)

Gibson, L. A.; Tyner, J. S.; Hawkins, S. A.; Lee, J.; Buchanan, J. R.

2011-12-01

Steroidal hormones, such as 17β-estradiol (E2), are prevalent in animal waste and are a common subject of study due to potential stream and groundwater contamination. These particular hormones are labeled as Endocrine Disrupting Chemicals (EDCs) because of their developmental effects in reptiles and amphibians. Dairy waste at concentrated animal feeding operations is typically stored in a pond that is regulated by law to include an underlying soil liner with a minimal hydraulic conductivity to limit leaching beneath the pond, yet some studies have traced stream and groundwater contamination to these ponds. Previous studies have shown that the soil underlying earthen ponds are always unsaturated. This increases the pore water velocity relative to a given flux, which itself is dictated almost entirely by an organic seal that forms at the bottom of a waste pond. This increased velocity results in more rapid transport and less retention time within the vadose zone where E2 could biodegrade into its daughter product, estrone (E1). And since the soil is unsaturated and therefore has a negative pressure, preferential flow should not serve as a method of transport. On the contrary, E2 and E1 may sorb to mobile colloids increasing their mobility. This study will evaluate the use of biochar, an increasingly common activated carbon source, as a soil liner amendment. Biochar has a specific surface area that can exceed 1,500 m2/g and is high in organic matter, which E2 sorbs to strongly. The biochar amendment should be most effective and enduring as a layer located at the bottom of the soil liner so that the leachate has been treated by the soil prior to contact. Another proposed amendment technique is to uniformly mix the biochar within the soil liner to increase the leachate contact time with the biochar, but realistically could prove to be too costly and energy-intensive. Field and laboratory studies were conducted to analyze hormone persistence and transport processes and to evaluate the effectiveness of biochar as a remediation practice. 80 cm long soil cores were collected beneath an active dairy waste storage pond and analyzed for moisture content, E1, and E2 concentrations. A laboratory soil column study was also conducted, including intact soil cores from the field, sand and clay packed columns, and packed soil columns with powdered biochar as a layer at the bottom of the columns and also as a uniformly mixed soil amendment to test its ability in retarding E2. A 2.3 m column of waste was maintained on all soil columns for three months, leachate was analyzed, and the columns were dissected for moisture content and E2 and E1 concentration profiles at the conclusion of the study. Preliminary results will be presented from these studies. With a better understanding of persistence and transport processes, remediation techniques can be applied and evaluated for their effectiveness in retarding (and degrading) these environmentally harmful EDCs.

Could organic matter have been preserved on Mars for 3.5 billion years?

NASA Technical Reports Server (NTRS)

Kanavarioti, Anastassia; Mancinelli, Rocco L.

1990-01-01

About 3.5 Gyr ago, when it is thought that Mars and earth had similar climates, biological evolution on earth had made considerable progress, such that life was abundant. It is therefore surmised that prior to this time period, the advent of chemical evolution and subsequent origin of life occurred on earth and may have occurred on Mars. Analysis for organic compounds in the soil buried beneath the Martian surface may yield useful information regarding the occurrence of chemical evolution and possibly biological evolution. Calculations based on the stability of amino acids lead to the conclusion that remnants of these compounds, if they existed on Mars 3.5 Gyr ago, might have been preserved buried beneath the surface oxidizing layer. For example, if phenylalanine, an amino acid of average stability, existed on Mars 3.5 Gyr ago, then 1.6 percent would remain buried today. Martian soil may exist from remnants of meteoritic and cometary bombardment, assuming that 1 percent of the organics survived impact.

Effects of groundwater-flow paths on nitrate concentrations across two riparian forest corridors

USGS Publications Warehouse

Speiran, Gary K.

2010-01-01

Groundwater levels, apparent age, and chemistry from field sites and groundwater-flow modeling of hypothetical aquifers collectively indicate that groundwater-flow paths contribute to differences in nitrate concentrations across riparian corridors. At sites in Virginia (one coastal and one Piedmont), lowland forested wetlands separate upland fields from nearby surface waters (an estuary and a stream). At the coastal site, nitrate concentrations near the water table decreased from more than 10 mg/L beneath fields to 2 mg/L beneath a riparian forest buffer because recharge through the buffer forced water with concentrations greater than 5 mg/L to flow deeper beneath the buffer. Diurnal changes in groundwater levels up to 0.25 meters at the coastal site reflect flow from the water table into unsaturated soil where roots remove water and nitrate dissolved in it. Decreases in aquifer thickness caused by declines in the water table and decreases in horizontal hydraulic gradients from the uplands to the wetlands indicate that more than 95% of the groundwater discharged to the wetlands. Such discharge through organic soil can reduce nitrate concentrations by denitrification. Model simulations are consistent with field results, showing downward flow approaching toe slopes and surface waters to which groundwater discharges. These effects show the importance of buffer placement over use of fixed-width, streamside buffers to control nitrate concentrations.

Nitrate in groundwater of the United States, 1991-2003

USGS Publications Warehouse

Burow, Karen R.; Nolan, Bernard T.; Rupert, Michael G.; Dubrovsky, Neil M.

2010-01-01

An assessment of nitrate concentrations in groundwater in the United States indicates that concentrations are highest in shallow, oxic groundwater beneath areas with high N inputs. During 1991-2003, 5101 wells were sampled in 51 study areas throughout the U.S. as part of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) program. The well networks reflect the existing used resource represented by domestic wells in major aquifers (major aquifer studies), and recently recharged groundwater beneath dominant land-surface activities (land-use studies). Nitrate concentrations were highest in shallow groundwater beneath agricultural land use in areas with well-drained soils and oxic geochemical conditions. Nitrate concentrations were lowest in deep groundwater where groundwater is reduced, or where groundwater is older and hence concentrations reflect historically low N application rates. Classification and regression tree analysis was used to identify the relative importance of N inputs, biogeochemical processes, and physical aquifer properties in explaining nitrate concentrations in groundwater. Factors ranked by reduction in sum of squares indicate that dissolved iron concentrations explained most of the variation in groundwater nitrate concentration, followed by manganese, calcium, farm N fertilizer inputs, percent well-drained soils, and dissolved oxygen. Overall, nitrate concentrations in groundwater are most significantly affected by redox conditions, followed by nonpoint-source N inputs. Other water-quality indicators and physical variables had a secondary influence on nitrate concentrations.

Autotrophic and Heterotrophic Controls over Winter Soil Carbon Cycling in a Subalpine Forest Ecosystem

NASA Astrophysics Data System (ADS)

Monson, R. K.; Scott-Denton, L. E.; Lipson, D. A.; Weintrub, M. N.; Rosenstiel, T. N.; Schmidt, S. K.; Williams, M. W.; Burns, S. P.; Delany, A. E.; Turnipseed, A. A.

2005-12-01

Studies were conducted at the Niwot Ridge Ameriflux site to understand wintertime soil carbon cycling and its control over ecosystem respiration. Wintertime respiration in this ecosystem results in the loss of 60-90% of the carbon assimilated the previous growing season. Thus, an understanding of the controls over winter carbon cycling is required to understand controls over the annual carbon budget. Trees were girdled to prevent the transport of photosynthates to the rhizosphere. In plots with non-girdled trees a large mid-winter pulse of sucrose was observed to enter the soil. In plots with girdled trees, no sucrose pulse was observed. Trees of this ecosystem are not photosynthetically active during the winter, leading us to conclude that the sucrose pulse is due to the death of fine roots that had accumulated sucrose the previous autumn. The sucrose pulse is potentially utilized by a novel winter community of microbes. Using DNA fingerprinting we discovered that the dominant isolates from the winter soils were from Jathinobacter, whereas the summer isolates were from Burkholderia. The winter community was capable of high rates of respiration and exponential growth at low temperatures, whereas the summer community was not. Our winter observations also indicated high activity of N-acetyl-C-glucosaminidase, one of the principal enzymes involved in chitin degradation. The presence of such high chitinase activities implicates decomposing fungal biomass as a principle source of CO2 beneath the snow pack. Using a novel in situ, beneath-snow CO2 measurement system, we observed unprecedented Q10 values for winter respiration, being 98 and 8.44 x 104 for the soil next to tree boles or within the open spaces between trees, respectively. These high Q10 values are likely the result of fractional changes in the availability of liquid water below 0°C and responses of microbial biomass to changes in the liquid water fraction. Using six-years of eddy covariance data, we showed that interannual variation in winter ecosystem respiration is positively correlated to interannual variation in the spring snow depth. Years with a with a deeper spring snow pack exhibited higher soil temperatures, and concomitantly higher soil respiration rates. Given the recently reported decadal-scale trend in decreasing snow pack in the Western U.S., which is coupled to warm climate anomalies, our observations indicate the potential for higher wintertime soil carbon sequestration due to lower winter ecosystem respiration rates in subalpine forests. Our studies of processes beneath the winter snow pack demonstrate that contrary to previous assumptions, winter biogeochemical processing of soil organic matter is an important component of ecosystem carbon budgets. Despite low temperatures and an inactive plant rhizosphere, winter microbial communities and exoenzymes appear to be active, carbon substrates appear to be in relatively high abundance and soil respiration rates appear to be sensitive to seasonal and interannual winter climate variability.

TEGA Whirligig Model

NASA Image and Video Library

2008-06-09

This is a photo of an engineering model of the Thermal and Evolved-Gas Analyzer TEGA instrument on board NASA Phoenix Mars Lander. This view shows a TEGA oven-loading mechanism beneath the input screen.

Mobility of Particulate and Dissolved Munitions Constituents in the Vadose Zone at Operational Ranges

DTIC Science & Technology

2011-08-05

rates with an identical film thickness value . Our results indicated that breakthrough curves at concentrations less than the compound’s solubility...soil microorganisms , respectively (Clausen et al., 2006). Consequently, the risk of contamination to aquifers beneath military operational ranges was...RDX sorption was carried out in the e 0-60 mg/L and 0-15 mg/L respectively. 0.5 g soil was added to 30 mL solutions of TNT and RDX adjusted for

PERFORMANCE OF A NEW PASSIVE DIFFUSION SAMPLER FOR SOIL GAS AND GROUND WATER SAMPLING

EPA Science Inventory

Conventional practice to estimate intrusion of fuel vapors from ground water to buildings measures the concentration of BTEX in ground water beneath the building using a conventional well screened across the water table. Conventional practice assumes that the concentration of co...

Assessment of soil and wash water quality beneath salt-spreader racks.

DOT National Transportation Integrated Search

2008-01-01

The Virginia Department of Transportation's (VDOT) winter maintenance program hinges primarily on the use of granular NaCl for deicing. On average, VDOT applies more than 300,000 tons of NaCl each winter season. The majority of this salt is spread by...

KSC-07pd1649

NASA Image and Video Library

2007-06-26

KENNEDY SPACE CENTER, FLA. -- In the Payload Hazardous Servicing Facility, photographers dressed in clean-room suits, are able to get closeup shots of the Phoenix Mars Lander. Phoenix is scheduled to launch Aug. 3 from Launch Pad 17-A at Cape Canaveral Air Force Station. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Kim Shiflett

KSC-07pd1651

NASA Image and Video Library

2007-06-26

KENNEDY SPACE CENTER, FLA. -- In the Payload Hazardous Servicing Facility, photographers dressed in clean-room suits are able to get closeup shots of the Phoenix Mars Lander. Phoenix is scheduled to launch Aug. 3 from Launch Pad 17-A at Cape Canaveral Air Force Station. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Kim Shiflett

KSC-07pd2006

NASA Image and Video Library

2007-07-19

KENNEDY SPACE CENTER, Fla. -- In the Payload Hazardous Servicing Facility, workers remove the covering over the heat shield (foreground) for the Phoenix Mars Lander spacecraft before installation. Targeted for launch from Cape Canaveral Air Force Station on Aug. 3, Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Troy Cryder

KSC-07pd1699

NASA Image and Video Library

2007-06-28

KENNEDY SPACE CENTER, FLA. -- On Launch Pad 17-A at Cape Canaveral Air Force Station, workers prepare the second stage of the Delta II launch vehicle to be mated to the Delta first stage below. Phoenix is scheduled to launch Aug. 3. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Kim Shiflett

KSC-07pd2173

NASA Image and Video Library

2007-08-04

KENNEDY SPACE CENTER, FLA. - NASA's Phoenix Mars lander lifts off from Pad 17A aboard a Delta II 7925 rocket at 5:26 a.m. EDT, illuminating the night sky over Cape Canaveral Air Force Station. Phoenix will land in icy soils near the north polar, permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Regina Mitchell-Ryall and Jerry Cannon

KSC-07pd2098

NASA Image and Video Library

2007-07-23

KENNEDY SPACE CENTER, FLA. -- Inside the mobile service tower of Launch Pad 17-A at Cape Canaveral Air Force Station in Florida, workers removed the plastic covering from NASA's Phoenix Mars Lander. Phoenix is scheduled to launch on the Delta II launch vehicle no earlier than Aug. 3. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, detected high concentrations of ice just beneath the top layer of soil. NASA/George Shelton

Phoenix Spacecraft Heat Shield Deployment Test

NASA Image and Video Library

2007-05-16

In the Payload Hazardous Servicing Facility, a worker monitors the Phoenix spacecraft during a heat shield deployment test, with a firing of ordnance associated with the separation device. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Launch of Phoenix aboard a Delta II rocket is targeted for Aug. 3 from Cape Canaveral Air Force Station in Florida.

Phoenix Spacecraft Heat Shield Deployment Test

NASA Image and Video Library

2007-05-16

In the Payload Hazardous Servicing Facility, workers monitor the Phoenix spacecraft during a heat shield deployment test, with a firing of ordnance associated with the separation device. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Launch of Phoenix aboard a Delta II rocket is targeted for Aug. 3 from Cape Canaveral Air Force Station in Florida.

KSC-07pd2182

NASA Image and Video Library

2007-08-04

KENNEDY SPACE CENTER, FLA. - NASA's Phoenix Mars lander illuminates Launch Pad 17A as it lifts off aboard a Delta II 7925 rocket at 5:26 a.m. EDT from Cape Canaveral Air Force Station. Phoenix will land in icy soils near the north polar, permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Tony Gray and Robert Murray

KSC-07pd1697

NASA Image and Video Library

2007-06-28

KENNEDY SPACE CENTER, FLA. -- On Launch Pad 17-A at Cape Canaveral Air Force Station, workers supervise the lowering of the second stage of the Delta II launch vehicle toward the Delta's first stage below. Phoenix is scheduled to launch Aug. 3. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Kim Shiflett

KSC-07pd2010

NASA Image and Video Library

2007-07-19

KENNEDY SPACE CENTER, Fla. --In the Payload Hazardous Servicing Facility, the heat shield for the Phoenix Mars Lander spacecraft is moved toward the spacecraft, in the background. Targeted for launch from Cape Canaveral Air Force Station on Aug. 3, Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Troy Cryder

KSC-07pd2172

NASA Image and Video Library

2007-08-04

KENNEDY SPACE CENTER, FLA. - NASA's Phoenix Mars lander lifts off from Pad 17A aboard a Delta II 7925 rocket amid billows of smoke at Cape Canaveral Air Force Station at 5:26 a.m. EDT. Phoenix will land in icy soils near the north polar, permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Regina Mitchell-Ryall and Jerry Cannon

KSC-07pd1549

NASA Image and Video Library

2007-06-18

KENNEDY SPACE CENTER, FLA. -- The first stage of a Delta II rocket arrives on Launch Pad 17-A at Cape Canaveral Air Force Station. The rocket is the launch vehicle for the Phoenix spacecraft, targeted for launch on Aug. 3 heading for Mars. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Amanda Diller

KSC-07pd1904

NASA Image and Video Library

2007-07-17

KENNEDY SPACE CENTER, Fla. -- In the Payload Hazardous Servicing Facility, the Phoenix Mars Lander spacecraft is lifted from its stand. The Phoenix will be moved to the upper stage booster for mating. Targeted for launch from Cape Canaveral Air Force Station on Aug. 3, Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Dimitri Gerondidakis

KSC-07pd2181

NASA Image and Video Library

2007-08-04

KENNEDY SPACE CENTER, FLA. - The Delta II 7925 rocket carrying NASA's Phoenix Mars lander lifts off at 5:26 a.m. EDT amid billows of smoke on Pad 17A at Cape Canaveral Air Force Station. Phoenix will land in icy soils near the north polar, permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Tony Gray and Robert Murray

KSC-07pd2180

NASA Image and Video Library

2007-08-04

KENNEDY SPACE CENTER, FLA. - NASA's Phoenix spacecraft makes an auspicious start on its journey to Mars aboard a Delta II 7925 rocket at 5:26 a.m. EDT from Pad 17A at Cape Canaveral Air Force Station. Phoenix will land in icy soils near the north polar, permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Tony Gray and Robert Murray

KSC-07pd2174

NASA Image and Video Library

2007-08-04

KENNEDY SPACE CENTER, FLA. - NASA's Phoenix Mars lander lifts off from Pad 17A aboard a Delta II 7925 rocket at 5:26 a.m. EDT, illuminating the pad at Cape Canaveral Air Force Station. Phoenix will land in icy soils near the north polar, permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Regina Mitchell-Ryall and Jerry Cannon

KSC-07pd1908

NASA Image and Video Library

2007-07-17

KENNEDY SPACE CENTER, Fla. -- In the Payload Hazardous Servicing Facility, workers guide the Phoenix Mars Lander spacecraft onto the upper stage booster. The spacecraft and booster will be mated for launch. Targeted for launch from Cape Canaveral Air Force Station on Aug. 3, Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. NASA/Dimitri Gerondidakis

KSC-07pd1903

NASA Image and Video Library

2007-07-17

KENNEDY SPACE CENTER, Fla. -- In the Payload Hazardous Servicing Facility, workers attach an overhead crane to the Phoenix Mars Lander spacecraft. The Phoenix will be lifted and moved to the upper stage booster for mating. Targeted for launch from Cape Canaveral Air Force Station on Aug. 3, Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. NASA/Dimitri Gerondidakis

KSC-07pd1700

NASA Image and Video Library

2007-06-28

KENNEDY SPACE CENTER, FLA. -- On Launch Pad 17-A at Cape Canaveral Air Force Station, workers begin mating the second stage of the Delta II launch vehicle to the Delta first stage below. Phoenix is scheduled to launch Aug. 3. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Kim Shiflett

KSC-07pd2175

NASA Image and Video Library

2007-08-04

KENNEDY SPACE CENTER, FLA. - NASA's Phoenix spacecraft makes a dramatic start on its mission to Mars aboard a Delta II 7925 rocket at 5:26 a.m. EDT from Pad 17A at Cape Canaveral Air Force Station. Phoenix will land in icy soils near the north polar, permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Tony Gray and Robert Murray

KSC-07pd1900

NASA Image and Video Library

2007-07-17

KENNEDY SPACE CENTER, Fla. -- In the Payload Hazardous Servicing Facility, workers prepare the Phoenix Mars Lander spacecraft for rotation. After rotation, the Phoenix will be mated with the upper stage booster. Targeted for launch from Cape Canaveral Air Force Station on Aug. 3, Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. NASA/Dimitri Gerondidakis

KSC-07pd1698

NASA Image and Video Library

2007-06-28

KENNEDY SPACE CENTER, FLA. -- On Launch Pad 17-A at Cape Canaveral Air Force Station, workers supervise the lowering of the second stage of the Delta II launch vehicle toward the Delta's first stage below. Phoenix is scheduled to launch Aug. 3. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Kim Shiflett

Viking Lander's Buried Footpad #3

NASA Technical Reports Server (NTRS)

1976-01-01

One of Viking l's three feet, which should be visible in this view, lies buried beneath a cover of loose Martian soil. This picture, taken Sunday (August 1), is the first to show the buried footpad #3. If not buried, the edge of the foot would be seen extending across the picture about midway between top and bottom. The foot sank about five inches, and fine-grained soil slumped into the depression and over the foot. The cracked nature of the surface near the slump area and the small, steep cliff at left indicates that the material is weakly cohesive. The surface material here is very similar mechanically to lunar soil.

Geophysical techniques for reconnaissance investigations of soils and surficial deposits in mountainous terrain

USGS Publications Warehouse

Olson, C.G.; Doolittle, J.A.

1985-01-01

Two techniques were assessed for their capabilities in reconnaissance studies of soil characteristics: depth to the water table and depth to bedrock beneath surficial deposits in mountainous terrain. Ground-penetrating radar had the best near-surface resolution in the upper 2 m of the profile and provided continuous interpretable imagery of soil profiles and bedrock surfaces. Where thick colluvium blankets side slopes, the GPR could not consistently define the bedrock interface. In areas with clayey or shaley sediments, the GPR is also more limited in defining depth and is less reliable. Seismic refraction proved useful in determining the elevation of the water table and depth to bedrock, regardless of thickness of overlying material, but could not distinguish soil-profile characteristics.-from Authors

Characteristics and engineering properties of residual soil of volcanic deposits

NASA Astrophysics Data System (ADS)

Wibawa, Y. S.; Sugiarti, K.; Soebowo, E.

2018-02-01

Residual soil knowledge of volcanic-sedimentary rock products provides important information on the soil bearing capacity and its engineering properties. The residual soil is the result of weathering commonly found in unsaturated conditions, having varied geotechnical characteristics at each level of weathering. This paper summarizes the results of the research from the basic engineering properties of residual soil of volcanic-sedimentary rocks from several different locations. The main engineering properties of residual soil such as specific gravity, porosity, grain size, clay content (X-Ray test) and soil shear strength are performed on volcanic rock deposits. The results show that the variation of the index and engineering properties and the microstructure properties of residual soil have the correlation between the depths of weathering levels. Pore volume and pore size distribution on weathered rock profiles can be used as an indication of weathering levels in the tropics.

Effects of Stormwater Infiltration on Quality of Groundwater Beneath Retention and Detention Basins

EPA Science Inventory

Use of stormwater retention and detention basins has become a popular method for managing urban and suburban stormwater runoff. Infiltration of stormwater through these basins may increase the risk to ground-water quality, especially in areas where the soil is sandy and the wate...

Mapping soil water content on golf course greens with GPR

USDA-ARS?s Scientific Manuscript database

Ground-penetrating radar (GPR) can be an effective and efficient method for high-resolution mapping of volumetric water content in the sand layer directly beneath the ground surface at a golf course green. This information could potentially be very useful to golf course superintendents for determi...

Report: Vapor Intrusion Health Risks at Bannister Federal Complex Not a Concern for Buildings 50 and 52, Unknown for Other Buildings

EPA Pesticide Factsheets

Report #11-P-0048, January 5, 2011. Testing at Bannister Federal Complex in February 2010 revealed elevated levels of volatile organic compounds (VOCs) in the soil vapor beneath the foundations of buildings 50 and 52.

What lies beneath, unraveling the mysteries of Rhizoctonia and Pythium

USDA-ARS?s Scientific Manuscript database

Washington wheat and barley growers have long recognized that the soil-borne fungal pathogens Rhizoctonia and Pythium cause root rot, stunting and poor emergence and can chip away at yield, resulting in annual losses of 10 percent or more. Since several of these Rhizoctonia and Pythium species attac...

Ground Water in a Fish Tank.

ERIC Educational Resources Information Center

Mayshark, Robin K.

1992-01-01

Describes creating a Model Aquatic/Terrestrial Ecosystem for use in helping students understand how water moves beneath the ground's surface. The model is constructed from a fish tank using rocks, soil, gravel, clay, and organic materials. Author describes possible cooperative-learning and problem-solving activities that can be done with this…

Beneath the Numbers: A Review of Gender Disparities in Undergraduate Education across Science, Technology, Engineering, and Math Disciplines

ERIC Educational Resources Information Center

Eddy, Sarah L.; Brownell, Sara E.

2016-01-01

This focused collection explores inequalities in the experiences of women in physics. Yet, it is important for researchers to also be aware of and draw insights from common patterns in the experiences of women across science, technology, engineering and mathematics (STEM) disciplines. Here, we review studies on gender disparities across college…

Hydrogeology and soil gas at J-Field, Aberdeen Proving Ground, Maryland

USGS Publications Warehouse

Hughes, W.B.

1993-01-01

Disposal of chemical warfare agents, munitions, and industrial chemicals in J-Field, Aberdeen Proving Ground, Maryland, has contaminated soil, groundwater and surface water. Seven exploratory borings and 38 observation wells were drilled to define the hydrogeologic framework at J-Field and to determine the type, extent, and movement of contaminants. The geologic units beneath J-Field consist of Coastal Plain sediments of the Cretaceous Patapsco Formation and Pleistocene Talbot Formation. The Patapsco Formation contains several laterally discontinuous aquifers and confining units. The Pleistocene deposits were divided into 3 hydrogeologic units--a surficial aquifer, a confining unit, and a confined aquifer. Water in the surficial aquifer flows laterally from topographically high areas to discharge areas in marshes and streams, and vertically to the underlying confined aquifer. In offshore areas, water flows from the deeper confined aquifers upward toward discharge areas in the Gunpowder River and Chesapeake Bay. Analyses of soil-gas samples showed high relative-flux values of chlorinated solvents, phthalates, and hydrocarbons at the toxic-materials disposal area, white-phosphorus disposal area, and riot-control-agent disposal area. The highest flux values were located downgradient of the toxic materials and white phosphorus disposal areas, indicating that groundwater contaminants are moving from source areas beneath the disposal pits toward discharge points in the marshes and estuaries. Elevated relative-flux values were measured upgradient and downgradient of the riot-control agent disposal area, and possibly result from soil and (or) groundwater contamination.

Hydrology of a groundwater-irrigated rice field in Bangladesh: Seasonal and daily mechanisms of infiltration

NASA Astrophysics Data System (ADS)

Neumann, Rebecca B.; Polizzotto, Matthew L.; Badruzzaman, A. Borhan M.; Ali, M. Ashraf; Zhang, Zhongyuan; Harvey, Charles F.

2009-09-01

Flow through a groundwater-irrigated rice field in Bangladesh was characterized with data collected from a transect of tensiometers and time domain reflectometry sensors, novel tracer tests, infiltration tests, soil core analyses, and calculated water budgets. The combined data captured the dynamic hydrologic behavior of the rice field over an entire growing season, which included many irrigation events. Recharge to the aquifer flowed from the surface of the rice field through preferential flow paths located in the subsoil beneath the plowed surface of the field and in the bunds, the raised boundaries around the perimeter of the field. Water that remained within the soil matrix did not recharge the aquifer. Bund flow was the dominant loss for the field because the bulk hydraulic conductivity of the soil beneath the bunds was greater than that in the plowed and planted region of the rice field. Each year, farmers plow the rice fields, destroying cracks and decreasing the conductivity of the shallow soil, but leave the bunds unplowed because they follow property boundaries. We determined bund flow with a daily water balance and confirmed its importance by comparing irrigation losses among fields of different sizes and geometries and hence different ratios of perimeter to area. The perimeter-to-area ratio predicted the fraction of water lost down the bunds for these and other fields located throughout Southeast Asia. Finally, we determined the economic and environmental benefits of reducing bund flow.

Reconnaissance of water quality in the High Plains Aquifer beneath agricultural lands, south-central Kansas

USGS Publications Warehouse

Stullken, L.E.; Stamer, J.K.; Carr, J.E.

1987-01-01

The High Plains of western Kansas was one of 14 areas selected for preliminary groundwater quality reconnaissance by the U.S. Geological Survey 's Toxic Waste--Groundwater Contamination Program. The specific objective was to evaluate the effects of land used for agriculture (irrigated cropland and non-irrigated rangeland) on the water in the High Plains aquifer. Conceptual inferences, based on the information available, would lead one to expect groundwater beneath irrigated cropland to contain larger concentrations of sodium, sulfate, chloride, nitrite plus nitrate, and some water soluble pesticides than water beneath non-irrigated land (range-land) The central part of the Great Bend Prairie, an area of about 1,800 sq mi overlying the High Plains aquifer in south-central Kansas, was selected for the study of agricultural land use because it has sand soils, a shallow water table, relatively large annual precipitation, and includes large areas that are exclusively irrigated cropland or non-irrigated rangeland. As determined by a two-tailed Wilcoxon rank-sum test, concentrations of sodium and alkalinity were significantly larger at the 95% confidence level for water samples from beneath irrigated cropland than from beneath rangeland. No statistically significant difference in concentrations of sulfate, chloride, nitrite plus nitrate, and ammonia, was detected. Concentrations of 2,4-D found in water samples from beneath the rangeland were larger at the 99% confidence level as compared to concentrations of 2,4-D in samples from beneath irrigated cropland. Larger concentrations of sodium and alkalinity were found in water beneath irrigated cropland, and the largest concentration of the pesticide atrazine (triazines were found in three samples) was found in water from the only irrigation well sampled. The sodium and atrazine concentrations found in water from the irrigation well support the premise that water-level drawdown develops under irrigated fields. This diverts the natural groundwater flow patterns, so that pumpage may cause recycling and subsequent concentration of leachates from the land surface. (Author 's abstract)

Structural Characterization of the 216-Z-9 Crib Prior to Decontamination and Demolition Using Robot Crawler and High Resolution Photography

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

Hopkins, A.; Sutter, C.; Klos, D.B.

2008-07-01

The Department of Energy, Richland Operations Office is preparing to conduct a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) removal action for the decontamination and demolition of the above-grade mining structures and equipment at the 216-Z-9 Crib. An investigation of the condition of the mining complex was initiated to determine constraints necessary for safely conducting the removal of the buildings. While crib headspace chemical analysis and nondestructive analysis of the interior of the buildings was completed to address radiological contamination concerns, the primary concern regarding the removal of the above-grade structures located on the crib cover involves determining themore » loading capacity and structural integrity of the crib cover slab. Additional concerns included headspace gases and radionuclide contamination. Until the structural analysis was completed, loading limits on the crib cover had been restricted. Photographic documentation revealed the loss of protective tiles and acid resistant coating from the underside of the cover raising a question of concrete stability. The investigation relied heavily on the use of high resolution photography with high intensity lighting for photographic documentation of the underside of the crib cover, followed by structural analysis of the documentation by a team of qualified engineers. Deployment of a robot crawler with attached camera and positioning of a fixed camera were integral to this structural characterization effort. Results of the photographic documentation were of sufficient quality to allow for bounding decisions to be made regarding the loading of the crib cover while performing the demolition of the mining structures (glovebox, excavator, bucket) and the associated buildings. The 216-Z-9 Crib, also known as the 216 Z-9 Recuplex CAW (CA column waste) Waste Disposal Cavern, the Z-9 Trench and the Z-9 Crib was constructed as an engineered trench with an open area beneath a concrete slab. The crib is located near the Plutonium Finishing Plant (PFP) facility, at the Hanford Nuclear Reservation in Eastern Washington State. The crib was used as a disposal site for effluent chemical and radiological wastes from the recovery of uranium and plutonium through extraction or RECUPLEX process, a method that recovered uranium and plutonium from liquid and solid wastes and scraps from other PFP processes. During its operating life, from 1955 through 1962, the Z-9 Crib received liquid wastes totaling approximately four million liters, or one million gallons. Analyses of the crib soil in seven locations to a depth of up to two meters (six feet) beneath the crib floor indicated that the plutonium content of the crib soil ranged from 50 to 150 kg (the highest concentration measured was 34.5 g/L of soil). While performing the structural evaluation of the crib cover, additional characterization information was obtained on the radiological and chemical conditions of the crib and structures. (authors)« less

"Dirt Cheap" Project Teaches Soils Engineering

ERIC Educational Resources Information Center

Roman, Harry T.

2010-01-01

This article describes a soil-testing activity that enables students to learn some interesting and useful things about how soil behaves under varied conditions. It offers a great way to give them a practical pre-engineering experience and will show them how engineers think about construction and how local soils influence building design. The…

Canopy tree species drive local heterogeneity in soil nitrogen availability in a lowland tropical forest

NASA Astrophysics Data System (ADS)

Osborne, B. B.; Nasto, M.; Asner, G. P.; Balzotti, C.; Cleveland, C. C.; Taylor, P.; Townsend, A. R.; Porder, S.

2016-12-01

The high phylogenetic and functional diversity of tree species in lowland tropical forests make field-based investigations of organismal influences on soil nutrient cycling challenging. Here, we used remotely-detected canopy nitrogen (N) data from the Carnegie Airborne Observatory to identify and characterize ¼ ha plots of a mature forest with either high or low canopy N on the Osa Peninsula in Costa Rica. Specifically we were interested in mechanisms by which foliar N might influence soil N, or the reverse. A non-dimensional scaling analysis suggested that high and low canopy N plots differ in their emergent (≥40 cm DBH) tree communities, though there were few putative N fixers in any of the plots. We found litterfall mass was similar beneath all canopies. However, mean DOC solubility of litter was 0.40% of dry biomass in low canopy N plots compared to 0.26% in high N plots. Additionally, litter leachate C:N was twice as high in litter from the low canopy N plots (61±1.4) compared with litter from the high N plots (30±1.4). We found strong positive correlations between canopy N and concentrations of soil KCl-extractable soil NO3- and net nitrification and net N mineralization rates (N=5; P<0.0001 in all cases). Under high canopy N, mean NO3-N concentrations were roughly an order of magnitude higher than beneath low N canopies (2.7±0.39 and 0.19±0.05, respectively). We hypothesize that differences in litter chemistry lead to differences in leachate quality that promote high soil N under canopies with high foliar N. Our findings suggest that remote sensing of foliar characteristics may offer an effective way to study spatial patterns in soil biogeochemistry in diverse tropical forests.

Changes in metal mobility associated with bark beetle-induced tree mortality.

PubMed

Mikkelson, Kristin M; Bearup, Lindsay A; Navarre-Sitchler, Alexis K; McCray, John E; Sharp, Jonathan O

2014-05-01

Recent large-scale beetle infestations have caused extensive mortality to conifer forests resulting in alterations to dissolved organic carbon (DOC) cycling, which in turn can impact metal mobility through complexation. This study analyzed soil-water samples beneath impacted trees in concert with laboratory flow-through soil column experiments to explore possible impacts of the bark beetle infestation on metal release and transport. The columns mimicked field conditions by introducing pine needle leachate and artificial rainwater through duplicate homogenized soil columns and measuring effluent metal (focusing on Al, Cu, and Zn) and DOC concentrations. All three metals were consistently found in higher concentrations in the effluent of columns receiving pine needle leachate. In both the field and laboratory, aluminum mobility was largely correlated with the hydrophobic fraction of the DOC, while copper had the largest correlation with total DOC concentrations. Geochemical speciation modeling supported the presence of DOC-metal complexes in column experiments. Copper soil water concentrations in field samples supported laboratory column results, as they were almost twice as high under grey phase trees than under red phase trees further signifying the importance of needle drop. Pine needle leachate contained high concentrations of Zn (0.1 mg l(-1)), which led to high effluent zinc concentrations and sorption of zinc to the soil matrix representing a future potential source for release. In support, field soil-water samples underneath beetle-impacted trees where the needles had recently fallen contained approximately 50% more zinc as samples from under beetle-impacted trees that still held their needles. The high concentrations of carbon in the pine needle leachate also led to increased sorption in the soil matrix creating the potential for subsequent carbon release. While unclear if manifested in adjacent surface waters, these results demonstrate an increased potential for Zn, Cu, and Al mobility, along with increased deposition of metals and carbon beneath beetle-impacted trees.

Soil microbial responses to nitrogen addition in arid ecosystems

DOE PAGES

Sinsabaugh, Robert L.; Belnap, Jayne; Rudgers, Jennifer; ...

2015-08-14

The N cycle of arid ecosystems is influenced by low soil organic matter, high soil pH, and extremes in water potential and temperature that lead to open canopies and development of biological soil crusts (biocrusts). We investigated the effects of N amendment on soil microbial dynamics in a Larrea tridentata-Ambrosia dumosa shrubland site in southern Nevada USA. Sites were fertilized with a NO 3-NH 4 mix at 0, 7, and 15 kg N ha -1 y -1 from March 2012 to March 2013. In March 2013, biocrust (0–0.5 cm) and bulk soils (0–10 cm) were collected beneath Ambrosia canopies andmore » in the interspaces between plants. Biomass responses were assessed as bacterial and fungal SSU rRNA gene copy number and chlorophyll a concentration. Metabolic responses were measured by five ecoenzyme activities and rates of N transformation. By most measures, nutrient availability, microbial biomass, and process rates were greater in soils beneath the shrub canopy compared to the interspace between plants, and greater in the surface biocrust horizon compared to the deeper 10 cm soil profile. Most measures responded positively to experimental N addition. Effect sizes were generally greater for bulk soil than biocrust. Results were incorporated into a meta-analysis of arid ecosystem responses to N amendment that included data from 14 other studies. Effect sizes were calculated for biomass and metabolic responses. Regressions of effect sizes, calculated for biomass, and metabolic responses, showed similar trends in relation to N application rate and N load (rate × duration). The critical points separating positive from negative treatment effects were 88 kg ha -1 y -1 and 159 kg ha -1, respectively, for biomass, and 70 kg ha -1 y -1 and 114 kg ha -1, respectively, for metabolism. These critical values are comparable to those for microbial biomass, decomposition rates and respiration reported in broader meta-analyses of N amendment effects in mesic ecosystems. As a result, large effect sizes at low N addition rates indicate that arid ecosystems are sensitive to modest increments in anthropogenic N deposition.« less

Hydrochemical evolution of sodium-sulfate and sodium-chloride groundwater beneath the Northern Chihuahuan Desert, Trans-Pecos, Texas, USA

USGS Publications Warehouse

Fisher, R.S.; Mullican, W. F.

1997-01-01

Groundwater beneath the northern Chihuahuan Desert, Trans-Pecos, Texas, USA, occurs in both carbonate and siliciclastic aquifers beneath a thick unsaturated zone and in shallow Rio Grande alluvium. Groundwater hydrochemical evolution was investigated by analyzing soils, soil leachates, bolson-fill sediments, water from the unsaturated zone, and groundwater from three major aquifers. Ionic relations, mineral saturation states, and geochemical modeling show that groundwater compositions are controlled by reactions in the unsaturated zone, mineralogy of unsaturated sediments and aquifers, position in the groundwater flow system, and extensive irrigation. Recharge to aquifers unaffected by irrigation is initially a Ca-HCO3 type as a result of dissolving carbonate surficial salts. With continued flow and mineral-water interaction, saturation with calcite and dolomite is maintained, gypsum is dissolved, and aqueous Ca and Mg are exchanged for adsorbed Na to produce a Na-SO4 water. Groundwater in Rio Grande alluvium is a Na-Cl type, reflecting river-water composition and the effects of irrigation, evapotranspiration, and surficial salt recycling. These results document two hydrochemical evolution paths for groundwater in arid lands. If recharge is dilute precipitation, significant changes in water chemistry can occur in unsaturated media, ion exchange can be as important as dissolution-precipitation reactions in determining groundwater composition, and mineral-water reactions ultimately control groundwater composition. If recharge is return flow of irrigation water that already contains appreciable solutes, mineral-water reactions are less important than irrigation-water composition in determining groundwater chemistry.

Nitrate in groundwater and water sources used by riparian trees in an agricultural watershed: A chemical and isotopic investigation in southern Minnesota

USGS Publications Warehouse

Komor, Stephen C.; Magner, Joseph A.

1996-01-01

This study evaluates processes that affect nitrate concentrations in groundwater beneath riparian zones in an agricultural watershed. Nitrate pathways in the upper 2 m of groundwater were investigated beneath wooded and grass-shrub riparian zones next to cultivated fields. Because trees can be important components of the overall nitrate pathway in wooded riparian zones, water sources used by riparian trees and possible effects of trees on nitrate concentrations in groundwater were also investigated. Average nitrate concentrations in shallow groundwater beneath the cultivated fields were 5.5 mg/L upgradient of the wooded riparian zone and 3.5 mg/L upgradient of the grass-shrub zone. Shallow groundwater beneath the fields passed through the riparian zones and discharged into streams that had average nitrate concentrations of 8.5 mg/L (as N). Lateral variations of δD values in groundwater showed that mixing among different water sources occurred beneath the riparian zones. In the wooded riparian zone, nitrate concentrations in shallow groundwater were diluted by upwelling, nitrate-poor, deep groundwater. Upwelling deep groundwater contained ammonium with a δ15N of 5‰ that upon nitrification and mixing with nitrate in shallow groundwater caused nitrate δ15N values in shallow groundwater to decrease by as much as 19.5‰. Stream water penetrated laterally beneath the wooded riparian zone as far as 19 m from the stream's edge and beneath the grass-shrub zone as far as 27 m from the stream's edge. Nitrate concentrations in shallow groundwater immediately upgradient of where it mixed with stream water averaged 0.4 mg/L in the wooded riparian zone and 0.8 mg/L near the grass-shrub riparian zone. Nitrate concentrations increased toward the streams because of mixing with nitrate-rich stream water. Because nitrate concentrations were larger in stream water than shallow groundwater, concentrated nitrate in the streams cannot have come from shallow groundwater at these sites. Water sources of riparian trees were identified by comparing δD values of sap water, soil water, groundwater, and stream water. Soil water was the main water source for trees in the outer 4 to 6 m of one part of the wooded riparian zone and outer 10 m of another part. Groundwater was a significant water source for trees closer to the streams where the water table was less than about 2.1 to 2.7 m below the surface. No evidence was found in the nitrate concentration profiles that trees close to the streams that took up groundwater through their roots also took up nitrate from groundwater. The lack of such evidence is attributed to the nitrate concentration profiles being insufficiently sensitive indicators of nitrate removal by trees.

Superfund Record of Decision Amendment (EPA Region 6): Texarkana Wood Preserving Co. , Texarkana, TX, March 13, 1998

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

Not Available

This decision document presents an amendment to the selected remedial action for the Texarkana Wood Preserving Co. Superfund Site. This amendment fundamentally changes the Record of Decision (ROD) executed by the Regional Administrator on September 25, 1990. This amended remedy will seal and contain soils contaminated with greater than 3 ppm (parts per million) benzo(a)pyrene equivalents, 2450 ppm total poly aromatic hydrocarbons (PAH), 20 ppb (parts per billion) as 2,3,7,8 TCDD equivalents and 150 ppm pentachlorophenol beneath a soil cap.

Evaluation of pore-water samplers at a drainage ditch, Installation Restoration Site 4, Naval Air Station Corpus Christi, Corpus Christi, Texas, 2005–06

USGS Publications Warehouse

Vroblesky, Don A.; Casey, Clifton C.

2007-01-01

The U.S. Geological Survey, in cooperation with the Naval Facilities Engineering Command Southeast, used innovative sampling methods to investigate ground-water contamination by chlorobenzenes beneath a drainage ditch on the southwestern side of Installation Restoration Site 4, Naval Air Station Corpus Christi, Corpus Christi, Texas, during 2005-06. The drainage ditch, which is a potential receptor for ground-water contaminants from Installation Restoration Site 4, intermittently discharges water to Corpus Christi Bay. This report evaluates a new type of pore-water sampler developed for this investigation to examine the subsurface contamination beneath the drainage ditch. The new type of pore-water sampler appears to be an effective approach for long-term monitoring of ground water in the sand and organic-rich mud beneath the drainage ditch.

Spatial and Temporal Changes in the Microbial Community in an Anaerobic Swine Waste Treatment Lagoon

USDA-ARS?s Scientific Manuscript database

Swine slurry is stored in pits beneath confinement buildings or in adjacent lagoons. This slurry is a valuable resource for crop fertilization and soil conditioning, but may also be a source of unpleasant odors. Microorganisms are crucial to all of the important processes that occur in anaerobic sto...

Influence of seasonal changes on the microbial community in an anaerobic swine waste treatment lagoon

USDA-ARS?s Scientific Manuscript database

Swine slurry is stored in pits beneath confinement buildings or in adjacent lagoons. This slurry is a valuable resource for crop fertilization and soil conditioning, but may also be a source of unpleasant odors. Microorganisms are crucial to all of the important processes that occur in anaerobic sto...

CONSTRUCTION AND INSTALLATION OF A NEW PASSIVE DIFFUSION SAMPLER CAPABLE OF MONITORING BENZENE IN EITHER SOIL GAS OR GROUND WATER

EPA Science Inventory

Conventional practice to estimate intrusion of fuel vapors from ground water to buildings measures the concentration of BTEX in ground water beneath the building using a conventional well screened across the water table. This practice assumes that the concentration of contaminant...

SITE CHARACTERIZATION OF A CHROMIUM SOURCE AREA AT THE USGS SUPPORT CENTER, ELIZABETH CITY, NC

EPA Science Inventory

Chromic and sulfuric acid wastes had discharged through a hole in the concrete floor of a chrome-plating shop located within a hangar at the U.S. Coast Guard Support Center near Elizabeth City, North Carolina and infiltrated the soils and groundwater beneath the shop. Following i...

Imaging tree roots with borehole radar

Treesearch

John R. Butnor; Kurt H. Johnsen; Per Wikstrom; Tomas Lundmark; Sune Linder

2006-01-01

Ground-penetrating radar has been used to de-tect and map tree roots using surface-based antennas in reflection mode. On amenable soils these methods can accurately detect lateral tree roots. In some tree species (e.g. Pinus taeda, Pinus palustris), vertically orientated tap roots directly beneath the tree, comprise most of the root mass. It is...

Could organic matter have been preserved on Mars for 3.5 billion years?

PubMed

Kanavarioti, A; Mancinelli, R L

1990-03-01

3.5 billion years (byr) ago, when it is thought that Mars and Earth had similar climates, biological evolution on Earth had made considerable progress, such that life was abundant. It is therefore surmised that prior to this time period the advent of chemical evolution and subsequent origin of life occurred on Earth and may have occurred on Mars. Analysis for organic compounds in the soil buried beneath the Martian surface may yield useful information regarding the occurrence of chemical evolution and possibly biological evolution. Calculations based on the stability of amino acids lead to the conclusion that remnants of these compounds, if they existed on Mars 3.5 byr ago, might have been preserved buried beneath the surface oxidizing layer. For example, if phenylalanine, an amino acid of average stability, existed on Mars 3.5 byr ago, then 1.6% would remain buried today, or 25 pg-2.5 ng of C g-1 Martian soil may exist from remnants of meteoritic and cometary bombardment, assuming that 1% of the organics survived impact.

KSC-2012-3091

NASA Image and Video Library

2012-05-26

CAPE CANAVERAL, Fla. - Teams taking part in NASA's Lunabotics Mining Competition gather inside the Apollo/Saturn V Center at Kennedy Space Center Visitor Complex in Florida for the awards ceremony at the end of the event. They are seated beneath the first stage of the Saturn V rocket that carried astronauts to the moon. The competition challenged university students to build machines that could collect soil such as the material found on the moon. Working inside the Caterpillar LunArena, the robotic craft dug soil that simulated lunar material. The event was judged by a machine's abilities to collect the soil, its design and operation, size, dust tolerance and its level of autonomy. Photo credit: NASA/Jim Grossmann

KSC-07pd2092

NASA Image and Video Library

2007-07-23

KENNEDY SPACE CENTER, FLA. -- Inside the mobile service tower of Launch Pad 17-A at Cape Canaveral Air Force Station in Florida, workers remove the container lid from NASA's Phoenix Mars Lander. Launch of Phoenix is scheduled to launch on the Delta II launch vehicle no earlier than Aug. 3. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, detected high concentrations of ice just beneath the top layer of soil. NASA/George Shelton

KSC-07pd1554

NASA Image and Video Library

2007-06-18

KENNEDY SPACE CENTER, FLA. -- On Launch Pad 17-A at Cape Canaveral Air Force Station, the first stage of a Delta II rocket has been lifted into the mobile service tower. The rocket is the launch vehicle for the Phoenix spacecraft, targeted for launch on Aug. 3 heading for Mars. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Amanda Diller

KSC-07pd1236

NASA Image and Video Library

2007-05-17

KENNEDY SPACE CENTER, FLA. -- In Hangar A&O on Cape Canaveral Air Force Station in Florida, workers conduct a steering test on the first stage of a Delta II rocket, at right. The rocket is designated for the launch of the Phoenix Mars Lander spacecraft. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Launch of Phoenix is targeted for Aug. 3. Photo credit: NASA/Kim Shiflett

KSC-07pd2101

NASA Image and Video Library

2007-07-23

KENNEDY SPACE CENTER, FLA. -- NASA's Phoenix Mars Lander is revealed inside the mobile service tower of Launch Pad 17-A at Cape Canaveral Air Force Station in Florida, after workers removed the coverings protecting the spacecraft. Launch of Phoenix on a Delta II launch vehicle is scheduled for no earlier than Aug. 3. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, detected high concentrations of ice just beneath the top layer of soil. NASA/George Shelton

KSC-07pd2091

NASA Image and Video Library

2007-07-23

KENNEDY SPACE CENTER, FLA. -- Inside the mobile service tower of Launch Pad 17-A at Cape Canaveral Air Force Station in Florida, workers remove the container from NASA's Phoenix Mars Lander. Launch of Phoenix is scheduled to launch on the Delta II launch vehicle no earlier than Aug. 3. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, detected high concentrations of ice just beneath the top layer of soil. NASA/George Shelton

KSC-07pd2096

NASA Image and Video Library

2007-07-23

KENNEDY SPACE CENTER, FLA. -- Inside the mobile service tower of Launch Pad 17-A at Cape Canaveral Air Force Station in Florida, workers begin to remove the plastic covering from NASA's Phoenix Mars Lander. Phoenix is scheduled to launch on the Delta II launch vehicle no earlier than Aug. 3. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, detected high concentrations of ice just beneath the top layer of soil. NASA/George Shelton

KSC-07pd1573

NASA Image and Video Library

2007-06-20

KENNEDY SPACE CENTER, FLA. -- In the Payload Hazardous Servicing Facility at Cape Canaveral Air Force Station, the solar array panels on the Phoenix Mars Lander spacecraft are unfolded. The deployment of the panels is part of the pre-launch testing under way. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Phoenix is scheduled to launch Aug. 3. Photo credit: NASA/George Shelton

KSC-07pd1905

NASA Image and Video Library

2007-07-17

KENNEDY SPACE CENTER, Fla. -- In the Payload Hazardous Servicing Facility, the Phoenix Mars Lander spacecraft is moved across the area toward the upper stage booster at right. The spacecraft and booster will be mated for launch. Targeted for launch from Cape Canaveral Air Force Station on Aug. 3, Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. NASA/Dimitri Gerondidakis

KSC-07pd1906

NASA Image and Video Library

2007-07-17

KENNEDY SPACE CENTER, Fla. -- In the Payload Hazardous Servicing Facility, workers help guide the suspended Phoenix Mars Lander spacecraft toward the upper stage booster in the center. The spacecraft and booster will be mated for launch. Targeted for launch from Cape Canaveral Air Force Station on Aug. 3, Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. NASA/Dimitri Gerondidakis

KSC-07pd1553

NASA Image and Video Library

2007-06-18

KENNEDY SPACE CENTER, FLA. -- On Launch Pad 17-A at Cape Canaveral Air Force Station, the first stage of a Delta II rocket is ready for lifting up into the mobile service tower. The rocket is the launch vehicle for the Phoenix spacecraft, targeted for launch on Aug. 3 heading for Mars. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Amanda Diller

KSC-07pd1234

NASA Image and Video Library

2007-05-17

KENNEDY SPACE CENTER, FLA. -- In Hangar A&O on Cape Canaveral Air Force Station in Florida, workers conduct a steering test on the first stage of a Delta II rocket. The rocket is designated for the launch of the Phoenix Mars Lander spacecraft. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Launch of Phoenix is targeted for Aug. 3. Photo credit: NASA/Kim Shiflett

KSC-07pd1237

NASA Image and Video Library

2007-05-17

KENNEDY SPACE CENTER, FLA. -- In Hangar A&O on Cape Canaveral Air Force Station in Florida, workers conduct a steering test on the first stage of a Delta II rocket. The rocket is designated for the launch of the Phoenix Mars Lander spacecraft. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Launch of Phoenix is targeted for Aug. 3. Photo credit: NASA/Kim Shiflett

KSC-07pd2090

NASA Image and Video Library

2007-07-23

KENNEDY SPACE CENTER, FLA. -- Inside the mobile service tower of Launch Pad 17-A at Cape Canaveral Air Force Station in Florida, workers remove the container from NASA's Phoenix Mars Lander. Launch of Phoenix is scheduled to launch on the Delta II launch vehicle no earlier than Aug. 3. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, detected high concentrations of ice just beneath the top layer of soil. NASA/George Shelton

KSC-07pd1619

NASA Image and Video Library

2007-06-22

KENNEDY SPACE CENTER, FLA. -- In the Payload Hazardous Servicing Facility, the Phoenix Mars Lander spacecraft undergoes illumination testing of its solar array panels. The Phoenix will be launched toward Mars to land in icy soils near the planet's north polar permanent ice cap. It will explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Phoenix is scheduled to launch Aug. 3 from Pad 17-A at Cape Canaveral Air Force Station . Photo credit: NASA/Kim Shiflett

KSC-07pd2099

NASA Image and Video Library

2007-07-23

KENNEDY SPACE CENTER, FLA. -- The top of NASA's Phoenix Mars Lander can be seen inside the mobile service tower of Launch Pad 17-A at Cape Canaveral Air Force Station in Florida. Launch of Phoenix on the Delta II launch vehicle is scheduled for no earlier than Aug. 3. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, detected high concentrations of ice just beneath the top layer of soil. NASA/George Shelton

KSC-07pd1568

NASA Image and Video Library

2007-06-20

KENNEDY SPACE CENTER, FLA. -- In the Payload Hazardous Servicing Facility at Cape Canaveral Air Force Station, this mesh bag holds the spring and bolt from the test firing to deploy the solar panels on the Phoenix Mars Lander spacecraft. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Phoenix is scheduled to launch Aug. 3. Photo credit: NASA/George Shelton

KSC-07pd1235

NASA Image and Video Library

2007-05-17

KENNEDY SPACE CENTER, FLA. -- In Hangar A&O on Cape Canaveral Air Force Station in Florida, workers conduct a steering test on the first stage of a Delta II rocket, at right. The rocket is designated for the launch of the Phoenix Mars Lander spacecraft. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Launch of Phoenix is targeted for Aug. 3. Photo credit: NASA/Kim Shiflett

KSC-07pd1618

NASA Image and Video Library

2007-06-22

KENNEDY SPACE CENTER, FLA. -- In the Payload Hazardous Servicing Facility, the Phoenix Mars Lander spacecraft undergoes illumination testing of its solar array panels. The Phoenix will be launched toward Mars to land in icy soils near the planet's north polar permanent ice cap. It will explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Phoenix is scheduled to launch Aug. 3 from Pad 17-A at Cape Canaveral Air Force Station . Photo credit: NASA/Kim Shiflett

KSC-07pd2093

NASA Image and Video Library

2007-07-23

KENNEDY SPACE CENTER, FLA. -- Inside the mobile service tower of Launch Pad 17-A at Cape Canaveral Air Force Station in Florida, the top of NASA's Phoenix Mars Lander can be seen after workers removed the container lid. Phoenix is scheduled to launch on the Delta II launch vehicle no earlier than Aug. 3. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, detected high concentrations of ice just beneath the top layer of soil. NASA/George Shelton

KSC-07pd2036

NASA Image and Video Library

2007-07-20

KENNEDY SPACE CENTER, Fla. -- In the Payload Hazardous Servicing Facility, the Phoenix Mars Lander is covered before the shipping canister is installed around it. After the canning, the Phoenix will be transferred to Launch Pad 17-A on Cape Canaveral Air Force Station in Florida for launch on Aug. 3. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Kim Shiflett

KSC-07pd1224

NASA Image and Video Library

2007-05-16

KENNEDY SPACE CENTER, FLA. -- In the Payload Hazardous Servicing Facility, workers monitor the Phoenix spacecraft during a heat shield deployment test, with a firing of ordnance associated with the separation device. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Launch of Phoenix aboard a Delta II rocket is targeted for Aug. 3 from Cape Canaveral Air Force Station in Florida. Photo credit: NASA/George Shelton

KSC-07pd1650

NASA Image and Video Library

2007-06-26

KENNEDY SPACE CENTER, FLA. -- In the Payload Hazardous Servicing Facility, a technician takes a measurement on the Phoenix Mars Lander. The spacecraft is on display for the media. Phoenix is scheduled to launch Aug. 3 from Launch Pad 17-A at Cape Canaveral Air Force Station. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Kim Shiflett

KSC-07pd2038

NASA Image and Video Library

2007-07-20

KENNEDY SPACE CENTER, Fla. -- In the Payload Hazardous Servicing Facility, workers complete installing segments of the shipping canister around the base of the Phoenix Mars Lander. After the canning, the Phoenix will be transferred to Launch Pad 17-A on Cape Canaveral Air Force Station in Florida for launch on Aug. 3. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Kim Shiflett

KSC-07pd1623

NASA Image and Video Library

2007-06-22

KENNEDY SPACE CENTER, FLA. -- After illumination testing of the solar array panels, technicians begin stowing the panels on the Phoenix Mars Lander spacecraft. The Phoenix will be launched toward Mars to land in icy soils near the planet's north polar permanent ice cap. It will explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Phoenix is scheduled to launch Aug. 3 from Pad 17-A at Cape Canaveral Air Force Station . Photo credit: NASA/Kim Shiflett

KSC-07pd1221

NASA Image and Video Library

2007-05-16

KENNEDY SPACE CENTER, FLA. -- In the Payload Hazardous Servicing Facility, workers prepare to put the Phoenix spacecraft through a heat shield deployment test, with a firing of ordnance associated with the separation device. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Launch of Phoenix aboard a Delta II rocket is targeted for Aug. 3 from Cape Canaveral Air Force Station in Florida. Photo credit: NASA/George Shelton

KSC-07pd2043

NASA Image and Video Library

2007-07-20

KENNEDY SPACE CENTER, Fla. -- In the Payload Hazardous Servicing Facility, workers secure the upper canister to the lower segments surrounding the Phoenix Mars Lander. After the canning, the Phoenix will be transferred to Launch Pad 17-A on Cape Canaveral Air Force Station in Florida for launch on Aug. 3. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Kim Shiflett

KSC-07pd1222

NASA Image and Video Library

2007-05-16

KENNEDY SPACE CENTER, FLA. -- In the Payload Hazardous Servicing Facility, the Phoenix spacecraft undergoes a heat shield deployment test, with a firing of ordnance associated with the separation device. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Launch of Phoenix aboard a Delta II rocket is targeted for Aug. 3 from Cape Canaveral Air Force Station in Florida. Photo credit: NASA/George Shelton

KSC-07pd2089

NASA Image and Video Library

2007-07-23

KENNEDY SPACE CENTER, FLA. -- Inside the mobile service tower of Launch Pad 17-A at Cape Canaveral Air Force Station in Florida, workers begin to remove the container from NASA's Phoenix Mars Lander. Launch of Phoenix is scheduled to launch on the Delta II launch vehicle no earlier than Aug. 3. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, detected high concentrations of ice just beneath the top layer of soil. NASA/George Shelton

Geologic Map of The Volcanoes Quadrangle, Bernalillo and Sandoval Counties, New Mexico

USGS Publications Warehouse

Thompson, Ren A.; Shroba, Ralph R.; Menges, Christopher M.; Schmidt, Dwight L.; Personius, Stephen F.; Brandt, Theodore R.

2009-01-01

This geologic map, in support of the U.S. Geological Survey Middle Rio Grande Basin Geologic Mapping Project, shows the spatial distribution of surficial deposits, lava flows, and related sediments of the Albuquerque volcanoes, upper Santa Fe Group sediments, faults, and fault-related structural features. These deposits are on, along, and beneath the Llano de Albuquerque (West Mesa) west of Albuquerque, New Mexico. Some of these deposits are in the western part of Petroglyph National Monument. Artificial fill deposits are mapped chiefly beneath and near the City of Albuquerque Soil Amendment Facility and the Double Eagle II Airport. Alluvial deposits were mapped in and along stream channels, beneath terrace surfaces, and on the Llano de Albuquerque and its adjacent hill slopes. Deposits composed of alluvium and colluvium are also mapped on hill slopes. Wedge-shaped deposits composed chiefly of sandy sheetwash deposits, eolian sand, and intercalated calcic soils have formed on the downthrown-sides of faults. Deposits of active and inactive eolian sand and sandy sheetwash deposits mantle the Llano de Albuquerque. Lava flows and related sediments of the Albuquerque volcanoes were mapped near the southeast corner of the map area. They include eleven young lava flow units and, where discernable, associated vent and near-vent pyroclastic deposits associated with cinder cones. Upper Santa Fe Group sediments are chiefly fluvial in origin, and are well exposed near the western boundary of the map area. From youngest to oldest they include a gravel unit, pebbly sand unit, tan sand and mud unit, tan sand unit, tan sand and clay unit, and silty sand unit. Undivided upper Santa Fe Group sediments are mapped in the eastern part of the map area. Faults were identified on the basis of surface expression determined from field mapping and interpretation of aeromagnetic data where concealed beneath surficial deposits. Fault-related structural features are exposed and were mapped near the western boundary of the map area.

Compendium of Abstracts on Statistical Applications in Geotechnical Engineering.

DTIC Science & Technology

1983-09-01

research in the application of probabilistic and statistical methods to soil mechanics, rock mechanics, and engineering geology problems have grown markedly...probability, statistics, soil mechanics, rock mechanics, and engineering geology. 2. The purpose of this report is to make available to the U. S...Deformation Dynamic Response Analysis Seepage, Soil Permeability and Piping Earthquake Engineering, Seismology, Settlement and Heave Seismic Risk Analysis

EFFECT OF BACTERIAL SULFATE REDUCTION ON IRON-CORROSION SCALES

EPA Science Inventory

Iron-sulfur geochemistry is important in many natural and engineered environments including drinking water systems. In the anaerobic environment beneath scales of corroding iron drinking water distribution system pipes, sulfate reducing bacteria (SRB) produce sulfide from natura...

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

Sinsabaugh, Robert L.; Belnap, Jayne; Rudgers, Jennifer

The N cycle of arid ecosystems is influenced by low soil organic matter, high soil pH, and extremes in water potential and temperature that lead to open canopies and development of biological soil crusts (biocrusts). We investigated the effects of N amendment on soil microbial dynamics in a Larrea tridentata-Ambrosia dumosa shrubland site in southern Nevada USA. Sites were fertilized with a NO 3-NH 4 mix at 0, 7, and 15 kg N ha -1 y -1 from March 2012 to March 2013. In March 2013, biocrust (0–0.5 cm) and bulk soils (0–10 cm) were collected beneath Ambrosia canopies andmore » in the interspaces between plants. Biomass responses were assessed as bacterial and fungal SSU rRNA gene copy number and chlorophyll a concentration. Metabolic responses were measured by five ecoenzyme activities and rates of N transformation. By most measures, nutrient availability, microbial biomass, and process rates were greater in soils beneath the shrub canopy compared to the interspace between plants, and greater in the surface biocrust horizon compared to the deeper 10 cm soil profile. Most measures responded positively to experimental N addition. Effect sizes were generally greater for bulk soil than biocrust. Results were incorporated into a meta-analysis of arid ecosystem responses to N amendment that included data from 14 other studies. Effect sizes were calculated for biomass and metabolic responses. Regressions of effect sizes, calculated for biomass, and metabolic responses, showed similar trends in relation to N application rate and N load (rate × duration). The critical points separating positive from negative treatment effects were 88 kg ha -1 y -1 and 159 kg ha -1, respectively, for biomass, and 70 kg ha -1 y -1 and 114 kg ha -1, respectively, for metabolism. These critical values are comparable to those for microbial biomass, decomposition rates and respiration reported in broader meta-analyses of N amendment effects in mesic ecosystems. As a result, large effect sizes at low N addition rates indicate that arid ecosystems are sensitive to modest increments in anthropogenic N deposition.« less

Low soil moisture during hot periods drives apparent negative temperature sensitivity of soil respiration in a dryland ecosystem: A multi-model comparison

USGS Publications Warehouse

Tucker, Colin; Reed, Sasha C.

2016-01-01

Arid and semiarid ecosystems (drylands) may dominate the trajectory of biosphere-to-atmosphere carbon (C) flux over the coming century. Accordingly, understanding dryland CO2 efflux controls is important for understanding C cycling at the global-scale: key unknowns regarding how temperature and moisture interact to regulate dryland C cycling remain. Further, the patchiness of dryland vegetation can create ‘islands of fertility’, with spatially heterogeneous rates of soil respiration (Rs). At our study site in southeastern Utah, USA we added or removed litter (0 to 650% of control) in paired plots that were either associated with a shrub or with interspaces between vascular plants. We measured Rs, soil temperature, and water content (θ) on eight sampling dates between October 2013 and November 2014. Rs was highest following monsoon rains in late summer when soil temperature was ~30°C. During mid-summer, Rs was low, associated with high soil temperatures (>40°C), resulting in an apparent negative temperature sensitivity of Rs at high temperatures, and positive temperature sensitivity at low-moderate temperatures. We used Bayesian statistical methods to compare multiple competing models capturing a wide range of hypothesized relationships between temperature, moisture, and Rs. The best fit model indicates apparent negative temperature sensitivity of soil respiration at high temperatures reflects the control of soil moisture – not high temperatures – in limiting Rs. The modeled Q10 ranged from 2.7 at 5°C to 1.4 at 45°C. Litter addition had no effect on temperature sensitivity or reference respiration (Rref = Rs at 20°C and optimum moisture) beneath shrubs, and little effect on Rref in interspaces, yet Rref was 1.5 times higher beneath shrubs than in interspaces. Together, these results suggest reduced Rs often observed at high temperatures in drylands is dominated by the control of moisture, and that variable litter inputs – at least over the short-term – exert minimal control over Rs.

Proposal and Research Direction of Soil Mass Organic Reorganization

NASA Astrophysics Data System (ADS)

Zhang, Lu; Han, Jichang

2018-01-01

Land engineering as a new discipline has been temporarily outrageous. The proposition of soil body organic reorganization undoubtedly enriches the research content for the construction of land engineering disciplines. Soil body organic reconstruction is designed to study how to realize the ecological ecology of the land by studying the external force of nature, to study the influence of sunlight, wind and water on soil body, how to improve the soil physical structure, to further strengthen the research of biological enzymes and microbes, and promote the release and utilization of beneficial inert elements in soil body. The emerging of frontier scientific research issues with soil body organic reorganization to indicate directions for the future development of soil engineering.

Long-term fate of depleted uranium at Aberdeen and Yuma Proving Grounds

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

Ebinger, M.H.; Essington, E.H.; Gladney, E.S.

1990-06-01

The environmental fate of fragments of depleted uranium (DU) penetrators in soils and waters at Aberdeen Proving Ground (APG) and Yuma Proving Ground (YPG) is a concern to the Testing and Evaluation Command (TECOM) of the US Army. This report presents the information from preliminary soil and water samples that were collected from the humid woodlands of APG and the arid Sonoran Desert of YPG. Soil samples collected beneath a penetrator fragment of the firing range at APG showed approximately 12% DU by weight in the surface horizon and DU significantly above background to a depth of about 20 cm.more » Samples of surface water at APG showed U only at background levels, and bottom sediments showed background U levels but with isotopic ratios of DU instead of natural U. Soil samples beneath a penetrator fragment at YPG showed about 0.5% by weight U in the surface horizon, but only background concentrations and isotopic ratios of U between 8 and 20 cm depth. Results from this preliminary study indicate that DU at APG was redistributed primarily be dissolution and transport with water and possibly by migration of DU colloids or DU attached to small particles. Redistribution at YPG, however, was mainly due to erosion of DU fragments from the impact area and redeposition in washes that drain the area. Proposed work for FY90-FY92 includes additional field sampling, laboratory column studies, and the development of a computer model of DU redistribution at both sites. 39 refs., 11 figs., 5 tabs.« less

Short seed longevity, variable germination conditions, and infrequent establishment events provide a narrow window for Yucca brevifolia (Agavaceae) recruitment

USGS Publications Warehouse

Bryant, M.; Reynolds, J.; DeFalco, Lesley A.; Esque, Todd C.

2012-01-01

PREMISE OF THE STUDY: The future of long-lived stand-forming desert plants such as Yucca brevifolia (Joshua tree) has come into question in light of climate variation and landscape-scale disturbances such as wildfire. Understanding plant establishment dynamics is important for mitigating the impacts of disturbances and promoting revegetation. • METHODS: We placed Y. brevifolia seeds in shallow caches and manipulated granivore access, nurse shrub effects, and the season of cache placement to determine conditions for seed germination and seedling establishment. • KEY RESULTS: Greatest seedling emergence occurred during spring and summer, when increased soil moisture was accompanied by warm soil temperatures. Late winter-spring emergence for cached seeds was enhanced beneath shrub canopies, but seedling survival declined beneath shrubs as temperatures increased in spring. Germinability of seed remaining in the soil was reduced from 50-68% after 12 mo residence time in soil and declined to <3% after 40 mo. Following dispersal from parent plants, seeds are either removed by granivores or lose germinability, imposing substantial losses of potential germinants. • CONCLUSIONS: Specific germination and establishment requirements impose stringent limits on recruitment rates for Y. brevifolia. Coupled with infrequent seed availability, the return rates to prefire densities and demographic structure may require decades to centuries, especially in light of potential changes to regional desert climate in combination with the potential for fire recurrence. Demographic patterns are predicted to vary spatially in response to environmental variability that limits recruitment and may already be apparent among extant populations.

Dynamics of nitrate and chloride during storm events in agricultural catchments with different subsurface drainage intensity (Indiana, USA)

USDA-ARS?s Scientific Manuscript database

Grids of perforated pipe buried beneath many poorly drained agricultural fields in the Midwestern U.S. are believed to “short circuit” pools of nitrate-laden soil water and shallow groundwater directly into streams that eventually discharge to the Mississippi River. Although much is known about the ...

Location and assessment of drainage pipes beneath farm fields and golf course greens using ground penetrating radar: A research summary

USDA-ARS?s Scientific Manuscript database

Enhancing the efficiency of soil water removal, and in turn crop productivity, on farmland already containing a subsurface drainage system, typically involves installing new drain lines between the old ones. However, before this approach can be attempted, the older drainage pipes need to be located...

Effect of weather, subsurface topography and fertilizer type on corn yields at the BARC experimental OPE3 site

USDA-ARS?s Scientific Manuscript database

Availability of soil water is critical for plant growth and development. In shallow groundwater conditions, this availability may vary with the depth to the restrictive layer that is found beneath groundwater. The restrictive layer is not flat, and the presence of the relief of this layer leads to t...

Rate of CCA leaching from commercially treated decking.

Treesearch

Stan Lebow; Daniel Foster; Patricia Lebow

2004-01-01

Conflicting reports on levels of arsenic in soil beneath decks treated with chromated copper arsenate (CCA) have raised concerns about arsenic exposure from this type of treated wood. This paper reports on an evaluation of the rate of release of copper, chromium, and arsenic from commercially treated lumber as a function of treatment additive (with or without water...

Remote camera monitoring and a mark – recapture study of the wandering salamander in a redwood forest canopy

Treesearch

Jim Campbell-Spickler; Stephen C. Sillett

2017-01-01

Crowns of old redwoods (Sequoia sempervirens (D. Don) Endl.) are teaming with life. Storm damage followed by recovery via trunk reiteration increases the structural complexity of redwood crowns over time. Bark and wood surfaces within complex redwood crowns accumulate debris and become covered with epiphytes. Arboreal soils develop beneath...

IET. Typical detail during Snaptran reactor experiments. Shielding bricks protect ...

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

IET. Typical detail during Snaptran reactor experiments. Shielding bricks protect ion chamber beneath reactor on dolly. Photographer: Page Comiskey. Date: August 11, 1965. INEEL negative no. 65-4039 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

Time series modelling of increased soil temperature anomalies during long period

NASA Astrophysics Data System (ADS)

Shirvani, Amin; Moradi, Farzad; Moosavi, Ali Akbar

2015-10-01

Soil temperature just beneath the soil surface is highly dynamic and has a direct impact on plant seed germination and is probably the most distinct and recognisable factor governing emergence. Autoregressive integrated moving average as a stochastic model was developed to predict the weekly soil temperature anomalies at 10 cm depth, one of the most important soil parameters. The weekly soil temperature anomalies for the periods of January1986-December 2011 and January 2012-December 2013 were taken into consideration to construct and test autoregressive integrated moving average models. The proposed model autoregressive integrated moving average (2,1,1) had a minimum value of Akaike information criterion and its estimated coefficients were different from zero at 5% significance level. The prediction of the weekly soil temperature anomalies during the test period using this proposed model indicated a high correlation coefficient between the observed and predicted data - that was 0.99 for lead time 1 week. Linear trend analysis indicated that the soil temperature anomalies warmed up significantly by 1.8°C during the period of 1986-2011.

A statistical and experimental approach for assessing the preservation of plant lipids in soil

NASA Astrophysics Data System (ADS)

Mueller, K. E.; Eissenstat, D. M.; Oleksyn, J.; Freeman, K. H.

2011-12-01

Plant-derived lipids contribute to stable soil organic matter, but further interpretations of their abundance in soils are limited because the factors that control lipid preservation are poorly understood. Using data from a long-term field experiment and simple statistical models, we provide novel constraints on several predictors of the concentration of hydrolyzable lipids in forest mineral soils. Focal lipids included common monomers of cutin, suberin, and plant waxes present in tree leaves and roots. Soil lipid concentrations were most strongly influenced by the concentrations of lipids in leaves and roots of the overlying trees, but were also affected by the type of lipid (e.g. alcohols vs. acids), lipid chain length, and whether lipids originated in leaves or roots. Collectively, these factors explained ~80% of the variation in soil lipid concentrations beneath 11 different tree species. In order to use soil lipid analyses to test and improve conceptual models of soil organic matter stabilization, additional studies that provide experimental and quantitative (i.e. statistical) constraints on plant lipid preservation are needed.

Pervasive and strong effects of plants on soil chemistry: a meta-analysis of individual plant 'Zinke' effects.

PubMed

Waring, Bonnie G; Álvarez-Cansino, Leonor; Barry, Kathryn E; Becklund, Kristen K; Dale, Sarah; Gei, Maria G; Keller, Adrienne B; Lopez, Omar R; Markesteijn, Lars; Mangan, Scott; Riggs, Charlotte E; Rodríguez-Ronderos, María Elizabeth; Segnitz, R Max; Schnitzer, Stefan A; Powers, Jennifer S

2015-08-07

Plant species leave a chemical signature in the soils below them, generating fine-scale spatial variation that drives ecological processes. Since the publication of a seminal paper on plant-mediated soil heterogeneity by Paul Zinke in 1962, a robust literature has developed examining effects of individual plants on their local environments (individual plant effects). Here, we synthesize this work using meta-analysis to show that plant effects are strong and pervasive across ecosystems on six continents. Overall, soil properties beneath individual plants differ from those of neighbours by an average of 41%. Although the magnitudes of individual plant effects exhibit weak relationships with climate and latitude, they are significantly stronger in deserts and tundra than forests, and weaker in intensively managed ecosystems. The ubiquitous effects of plant individuals and species on local soil properties imply that individual plant effects have a role in plant-soil feedbacks, linking individual plants with biogeochemical processes at the ecosystem scale. © 2015 The Author(s).

Evaluation of road failure vulnerability section through integrated geophysical and geotechnical studies

NASA Astrophysics Data System (ADS)

Adiat, K. A. N.; Akinlalu, A. A.; Adegoroye, A. A.

2017-06-01

In order to investigate the competence of the proposed road for pavement stability, geotechnical and geophysical investigations involving Land Magnetic, Very Low Frequency Electromagnetic (VLF-EM) and Electrical Resistivity methods were carried out along Akure-Ipinsa road Southwestern Nigeria. The magnetic profile was qualitatively and quantitatively interpreted to produce geomagnetic section that provides information on the basement topography and structural disposition beneath the proposed road. Similarly, the VLF-EM profile was equally interpreted to provide information on the possible occurrence of linear features beneath the study area. These linear features pose a potential risk to the proposed road as they are capable of undermining the stability of the pavement structure. The geoelectric parameters obtained from the quantitative interpretation of the VES data were used to generate geoelectric section. The geoelectric section generated shows that the study area was underlain by four geoelectric layers namely the topsoil, the weathered layer, the partly weathered/fractured basement and the fresh basement. The major part of the topsoil, which constitutes the subgrade, is characterized by relatively low resistivity values (<100 Ωm) suggestive of weak zones that are capable of undermining the stability of the proposed road. This therefore suggests that the layer is composed of incompetent materials that are unsuitable for engineering structures. Furthermore, fractured basement was also delineated beneath some portion of the proposed road. Since fracture is a weak zone, its presence can facilitate failure of the proposed road especially when it is occurring at shallow depth. The geotechnical results reveal that most of the investigated soil samples are clayey in nature. Integration of the results demonstrates that there is a good correlation between geophysical results and the geotechnical results. Furthermore, a vulnerability section that divided the road segments into three zones based on the degree of vulnerability was produced. These zones were high, moderate and low vulnerability zones. It is estimated that about 60% of the road segments constitutes moderate degree of vulnerability while 30% and 10% of the segments respectively constitute high and low degree of vulnerability.

Yogi the rock

NASA Technical Reports Server (NTRS)

1997-01-01

Yogi, a rock taller than rover Sojourner, is the subject of this image, taken by the deployed Imager for Mars Pathfinder (IMP) on Sol 3. The soil in the foreground will be the location of multiple soil mechanics experiments performed by Sojourner's cleated wheels. Pathfinder scientists will be able to control the force inflicted on the soil beneath the rover's wheels, giving them insight into the soil's mechanical properties.

The image was taken by the Imager for Mars Pathfinder (IMP) after its deployment on Sol 3. Mars Pathfinder was developed and managed by the Jet Propulsion Laboratory (JPL) for the National Aeronautics and Space Administration. JPL is an operating division of the California Institute of Technology (Caltech). The IMP was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

First record of Talaromyces udagawae in soil related to decomposing human remains in Argentina.

PubMed

Tranchida, María C; Centeno, Néstor D; Stenglein, Sebastián A; Cabello, Marta N

2016-01-01

The morphologic features of Talaromyces udagawae Stolk and Samson are here described and illustrated. This teleomorphic Ascomycota fungus was isolated from soil obtained in Buenos Aires province (Argentina) from beneath a human cadaver in an advanced state of decomposition. After washing and serial dilution of the soil along with moist-chamber techniques for fungal cultivation, T. udagawae formed very restricted colonies of bright yellow color on different growth media with 8-ascospored asci. The ascospores were ellipsoidal and ornamented. The anamorphic state was not observed. Molecular-genetic techniques identified the species. The present record is the first of the species in Argentina, pointing it as a tool to identify soils where cadaver decomposition occurs. Copyright © 2015 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

Mid-Level Soil Sample for Oven Number Seven

NASA Technical Reports Server (NTRS)

2008-01-01

Soil from a sample called Burning Coals was delivered through the doors of cell number seven (left) of the Thermal and Evolved-Gas Analyzer on NASA's Phoenix Mars Lander on Aug. 20, 2008, during the 85th Martian day, or sol, since Phoenix landed.

This image from Phoenix's Robotic Arm Camera shows some of the soil on the screen beneath the doors. One of the cell's two doors is fully open, the other partially open.

This soil sample comes from an intermediate depth between the ground surface and the hard, underground icy layer at the Phoenix site.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

Final report of the decontamination and decommissioning of Building 39 at the Grand Junction Projects Office Facility

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

Widdop, M.R.

1996-07-01

The U.S. Department of Energy (DOE) Grand Junction Projects Office (GJPO) occupies a 61.7-acre facility along the Gunnison River near Grand Junction, Colorado. This site was contaminated with uranium ore and mill tailings during uranium refining activities of the Manhattan Engineer District and during pilot milling experiments conducted for the U.S. Atomic Energy Commission`s domestic uranium procurement program. The DOE Defense Decontamination and Decommissioning Program established the GJPO Remedial Action Project to clean up and restore the facility lands, improvements, and the underlying aquifer. The site contractor for the facility, Rust Geotech, is also the remedial action contractor. The soilmore » beneath Building 39 was radiologically contaminated and the building was demolished in 1992. The soil area within the footprint of the building has been remediated in accordance with the identified standards and the area can be released for unlimited exposure and unrestricted use. This document was prepared in response to a DOE request for an individual final report for each contaminated GJPO building.« less

US Department of Energy Grand Junction Projects Office Remedial Action Project, final report of the decontamination and decommissioning of Building 36 at the Grand Junction Projects Office Facility

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

Widdop, M.R.

1996-08-01

The U.S. Department of Energy (DOE) Grand Junction Projects Office (GJPO) occupies a 61.7-acre facility along the Gunnison River near Grand Junction, Colorado. This site was contaminated with uranium ore and mill tailings during uranium refining activities of the Manhattan Engineer District and during pilot milling experiments conducted for the U.S. Atomic Energy Commission`s domestic uranium procurement program. The DOE Defense Decontamination and Decommissioning Program established the GJPO Remedial Action Project to clean up and restore the facility lands, improvements, and the underlying aquifer. The site contractor for the facility, Rust Geotech, also is the remedial action contractor. Building 36more » was found to be radiologically contaminated and was demolished in 1996. The soil beneath the building was remediated in accordance with identified standards and can be released for unlimited exposure and unrestricted use. This document was prepared in response to a DOE request for an individual final report for each contaminated GJPO building.« less

Final report of the decontamination and decommissioning of Building 1 at the Grand Junction Projects Office Facility

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

Widdop, M.R.

1996-08-01

The U.S. Department of Energy (DOE) Grand Junction Projects Office (GJPO) occupies a 61.7-acre facility along the Gunnison River near Grand Junction, Colorado. This site was contaminated with uranium ore and mill tailings during uranium refining activities of the Manhattan Engineer District and during pilot milling experiments conducted for the U.S. Atomic Energy Commission`s domestic uranium procurement program. The DOE Defense Decontamination and Decommissioning Program established the GJPO Remedial Action Project to clean up and restore the facility lands, improvements, and the underlying aquifer. The site contractor for the facility, Rust Geotech, also is the remedial action contractor. Building 1more » was found to be radiologically contaminated and was demolished in 1996. The soil beneath and adjacent to the building was remediated in accordance with identified standards and can be released for unlimited exposure and unrestricted use. This document was prepared in response to a DOE request for an individual final report for each contaminated GJPO building.« less

Comparative study of engineering properties of two-lime waste tire particle soil and soil with lime/loess ratio of 3:7

NASA Astrophysics Data System (ADS)

Tiecheng, Yan; Xingyuan, Zhang; Hongping, Yang

2018-03-01

This study describes an analytical comparison of the engineering characteristics of two-lime waste tire particle soil and soil with lime/loess ratio of 3:7 using density measurements, results of indoor consolidation tests, and direct shear tests to examine the strength and deformation characteristics. It investigates the engineering performance of collapsible loess treated with waste tire particles and lime. The results indicate that (1) the shear strength of the two-lime waste tire particle soils increases continuously with soil age; and (2) the two-lime waste tire particle soils are light-weight, strong, and low-deformation soils, and can be applied primarily to improve the foundation soil conditions in areas with collapsible loess soils. This could address the problem of used tire disposal, while providing a new method to consider and manage collapsible loess soils.

KSC-07pd2072

NASA Image and Video Library

2007-07-23

KENNEDY SPACE CENTER, FLA. — The Phoenix Mars Lander, on its transporter, is escorted out of the Payload Hazardous Servicing Facility for its transfer to Launch Pad 17-A at Cape Canaveral Air Force Station. Launch of NASA's Phoenix Mars Lander is scheduled for Aug. 3. There are two instantaneous launch times, 5:35:18 and 6:11:24 a.m. EDT. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. NASA/George Shelton

KSC-07pd1559

NASA Image and Video Library

2007-06-19

KENNEDY SPACE CENTER, FLA. -- On Pad 17-A at Cape Canaveral Air Force Station, the solid rocket booster is raised off its transporter. The SRB will be lifted into the mobile service tower for mating with the Delta II first stage. The Delta is the launch vehicle for the Phoenix Mars Lander spacecraft. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Phoenix is scheduled to launch Aug. 3. Photo credit: NASA/Kim Shiflett

KSC-07pd2008

NASA Image and Video Library

2007-07-19

KENNEDY SPACE CENTER, Fla. -- In the Payload Hazardous Servicing Facility, workers attach a crane to the heat shield for the Phoenix Mars Lander spacecraft. The crane will lift and move the heat shield for installation over the lander within the cruise stage. Targeted for launch from Cape Canaveral Air Force Station on Aug. 3, Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Troy Cryder

KSC-07pd1565

NASA Image and Video Library

2007-06-19

KENNEDY SPACE CENTER, FLA. -- On Pad 17-A at Cape Canaveral Air Force Station, three solid rocket boosters wait for the Delta II first stage to arrive at the mobile service tower. The SRBs will be mated with the Delta, which is the launch vehicle for the Phoenix Mars Lander spacecraft. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Phoenix is scheduled to launch Aug. 3. Photo credit: NASA/Kim Shiflett

KSC-07pd1553A

NASA Image and Video Library

2007-06-18

KENNEDY SPACE CENTER, FLA. -- On Launch Pad 17-A at Cape Canaveral Air Force Station, workers prepare the first stage of a Delta II rocket to be lifted up into the mobile service tower. The rocket is the launch vehicle for the Phoenix spacecraft, targeted for launch on Aug. 3 heading for Mars. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Amanda Diller

KSC-07pd1345

NASA Image and Video Library

2007-06-04

KENNEDY SPACE CENTER, FLA. -- In the Payload Handling Servicing Facility, the Phoenix spacecraft is upside down during rotation. The Phoenix mission is the first project in NASA's first openly competed program of Mars Scout missions. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. It will serve as NASA's first exploration of a potential modern habitat on Mars and open the door to a renewed search for carbon-bearing compounds, Photo credit: NASA/George Shelton

KSC-07pd1652

NASA Image and Video Library

2007-06-26

KENNEDY SPACE CENTER, FLA. -- In the Payload Hazardous Servicing Facility, Phoenix Program Manager Barry Goldstein, from the Jet Propulsion Laboratory, briefs media personnel dressed in clean-room suits about the mission of the Phoenix Mars Lander, in the background. Phoenix is scheduled to launch Aug. 3 from Launch Pad 17-A at Cape Canaveral Air Force Station. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Kim Shiflett

GEOCHEMISTRY OF SULFUR IN IRON CORROSION SCALES FOUND IN DRINKING WATER DISTRIBUTION SYSTEMS

EPA Science Inventory

Iron-sulfur geochemistry is important in many natural and engineered environments, including drinking water systems. In the anaerobic environment beneath scales of corroding iron drinking water distribution system pipes, sulfate reducing bacteria (SRB) produce sulfide from natu...

Red Cedar Invasion Along the Missouri River, South Dakota: Cause and Consequence

NASA Astrophysics Data System (ADS)

Greene, S.; Knox, J. C.

2012-12-01

This research evaluates drivers of and ecosystem response to red cedar (Juniperus virginiana) invasion of riparian surfaces downstream of Gavin's Point Dam on the Missouri River. Gavin's Point Dam changed the downstream geomorphology and hydrology of the river and its floodplain by reducing scouring floods and flood-deposited sediment. The native cottonwood species (Populus deltoides) favors cleared surfaces with little to no competitors to establish. Now that there are infrequent erosive floods along the riparian surfaces to remove competitor seeds and seedlings, other vegetation is able to establish. Red cedar is invading the understory of established cottonwood stands and post-dam riparian surfaces. To assess reasons and spatial patterns for the recent invasion of red cedar, a stratified random sampling of soil, tree density and frequency by species, and tree age of 14 forest stands was undertaken along 59 river kilometers of riparian habitat. Soil particle size was determined using laser diffraction and tree ages were estimated from ring counts of tree cores. As an indicator of ecosystem response to invasion, we measured organic matter content in soil collected beneath red cedar and cottonwood trees at three different depths. Of 565 red cedars, only two trees were established before the dam was built. We applied a multiple regression model of red cedar density as a function of cottonwood density and percent sand (63-1000 microns in diameter) in StatPlus© statistical software. Cottonwood density and percent sand are strongly correlated with invasion of red cedar along various riparian surfaces (n = 59, R2 = 0.42, p-values < 0.05). No significant differences exist between organic matter content of soil beneath red cedar and cottonwood trees (p-value > 0.05 for all depths). These findings suggest that the dam's minimization of downstream high-stage flows opened up new habitat for red cedar to establish. Fluvial geomorphic surfaces reflect soil type and cottonwood density and, in turn, predict susceptibility of a surface to red cedar invasion. Nonetheless, soils underlying red cedar and cottonwood trees are functionally similar with regard to soil organic matter content.

Martian Surface Beneath Phoenix

NASA Technical Reports Server (NTRS)

2008-01-01

This is an image of the Martian surface beneath NASA's Phoenix Mars Lander. The image was taken by Phoenix's Robotic Arm Camera (RAC) on the eighth Martian day of the mission, or Sol 8 (June 2, 2008). The light feature in the middle of the image below the leg is informally called 'Holy Cow.' The dust, shown in the dark foreground, has been blown off of 'Holy Cow' by Phoenix's thruster engines.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

DEMONSTRATION BULLETIN: NEW YORK STATE MULTI-VENDOR BIOREMEDIATION - ENSR CONSULTING AND ENGINEERING/LARSEN ENGINEERS EX-SITU BIOVAULT

EPA Science Inventory

The ENSR Biovault Treatment Process is an ex-situ bioremediation technology for the treatment of organic contaminated soils. Contaminated soils placed in specially designed soil piles, referred to as biovaults, are remediated by stimulating the indigenous soil microbes to prolife...

Soils and Foundations: A Syllabus.

ERIC Educational Resources Information Center

Long, Melvin J.

The teaching guide and course outline for a 12-week course in soils and foundations is designed to help student technicians in a two-year associate degree civil engineering technology program to obtain entry level employment as highway engineering aides, soil testing technicians, soil mappers, or construction inspectors. The seven teaching units…

Bioremediation of engine oil polluted soil by the tropical white rot fungus, Lentinus squarrosulus Mont. (Singer).

PubMed

Adenipekun, Clementina O; Isikhuemhen, Omoanghe S

2008-06-15

This study was conducted to test the efficacy of an indigenous white rot fungus Lentinus squarrosulus in degrading engine oil in soil. Flasks containing sterilized garden soil (100 g) moistened with 75% distilled water (w/v) were contaminated with engine oil 1, 2.5, 5, 10, 20 and 40% w/w concentrations, inoculated with L. squarrosulus and incubated at room temperature for 90 days. Levels of organic matter, pH, total hydrocarbon and elemental content (C, Cu, Fe, K, N, Ni, Zn and available P) were determined post-fungal treatment. Results indicate that contaminated soils inoculated with L. squarrosulus had increased organic matter, carbon and available phosphorus, while the nitrogen and available potassium was reduced. A relatively high percentage degradation of Total Petroleum Hydrocarbon (TPH) was observed at 1% engine oil concentration (94.46%), which decreased to 64.05% TPH degradation at 40% engine oil contaminated soil after 90 days of incubation. The concentrations of Fe, Cu, Zn and Ni recovered from straw/fungal biomass complex increased with the increase of engine-oil contamination and bio-accumulation by the white-rot fungus. The improvement of nutrient content values as well as the bioaccumulation of heavy metals at all levels of engine oil concentrations tested through inoculations with L. squarrosulus is of importance for the bioremediation of engine-oil polluted soils.

Development of an Engineering Soil Database

DTIC Science & Technology

2017-12-27

systems such as agricultural and geological soil classifications and soil parameters. Tier 3 Data were converted into equivalent USCS classification...14 2.7 U.S. Department of Agriculture (USDA) textural soil classification ............................ 16 2.7.1 Properties of USDA textural...Defense ERDC U.S. Army Engineer Research and Development Center ESDB European Soil Database FAO Food and Agriculture Organization (of the United

Teaching through Trade Books: The Dirt on Soil

ERIC Educational Resources Information Center

Royce, Christine Anne

2007-01-01

Have you ever played in the dirt? Repotted a plant? Planted a garden? In each and every one of these activities, you touched something that is a valuable resource in our lives--dirt! This month's column has students investigating different aspects of something that is right beneath our feet but plays an important role in the daily lives of many…

Assessment of metal retention in newly constructed highway embankments.

PubMed

Werkenthin, Moritz; Kluge, Björn; Wessolek, Gerd

2016-12-01

Newly constructed embankments should provide both a specific bearing capacity to enable trafficability in emergency cases and a sufficient pollutant retention capacity to protect the groundwater. A number of lysimeters were installed along the A115 highway to determine total and dissolved metal concentrations in road runoff and in the soil solution of newly constructed embankments. Dissolved concentrations in soil solution of the embankments did not exceed the trigger values of the German legislation. Depending on the metal, total concentrations in soil solution were more than twice as high as dissolved concentrations. The high infiltration rates lead to increased groundwater recharge beneath the embankments (up to 4100 mm a -1 ). Although metal concentrations were not problematic from the legislators' point of view, the elevated infiltration rates beside the road facilitated the transfer of high metal loads into deeper soil layers and potentially into the groundwater as well.

EAST FACE OF REACTOR BASE. COMING TOWARD CAMERA IS EXCAVATION ...

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

EAST FACE OF REACTOR BASE. COMING TOWARD CAMERA IS EXCAVATION FOR MTR CANAL. CAISSONS FLANK EACH SIDE. COUNTERFORT (SUPPORT PERPENDICULAR TO WHAT WILL BE THE LONG WALL OF THE CANAL) RESTS ATOP LEFT CAISSON. IN LOWER PART OF VIEW, DRILLERS PREPARE TRENCHES FOR SUPPORT BEAMS THAT WILL LIE BENEATH CANAL FLOOR. INL NEGATIVE NO. 739. Unknown Photographer, 10/6/1950 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

Spectral Assessment of Soil Properties: Standoff Quantification of Soil Organic Matter Content in Surface Mineral Soils and Alaskan Peat

DTIC Science & Technology

2017-08-01

ER D C TR -1 7- 9 ERDC 6.1 Geospatial Research and Engineering (GRE) and ERDC 6.2 GRE ARTEMIS STO-R DRTSPORE Spectral Assessment of...The U.S. Army Engineer Research and Development Center (ERDC) solves the nation’s toughest engineering and environmental challenges. ERDC...published by ERDC, visit the ERDC online library at http://acwc.sdp.sirsi.net/client/default. ERDC 6.1 Geospatial Research and Engineering (GRE) and

Soil engineering in vivo: harnessing natural biogeochemical systems for sustainable, multi-functional engineering solutions

PubMed Central

DeJong, Jason T.; Soga, Kenichi; Banwart, Steven A.; Whalley, W. Richard; Ginn, Timothy R.; Nelson, Douglas C.; Mortensen, Brina M.; Martinez, Brian C.; Barkouki, Tammer

2011-01-01

Carbon sequestration, infrastructure rehabilitation, brownfields clean-up, hazardous waste disposal, water resources protection and global warming—these twenty-first century challenges can neither be solved by the high-energy consumptive practices that hallmark industry today, nor by minor tweaking or optimization of these processes. A more radical, holistic approach is required to develop the sustainable solutions society needs. Most of the above challenges occur within, are supported on, are enabled by or grown from soil. Soil, contrary to conventional civil engineering thought, is a living system host to multiple simultaneous processes. It is proposed herein that ‘soil engineering in vivo’, wherein the natural capacity of soil as a living ecosystem is used to provide multiple solutions simultaneously, may provide new, innovative, sustainable solutions to some of these great challenges of the twenty-first century. This requires a multi-disciplinary perspective that embraces the science of biology, chemistry and physics and applies this knowledge to provide multi-functional civil and environmental engineering designs for the soil environment. For example, can native soil bacterial species moderate the carbonate cycle in soils to simultaneously solidify liquefiable soil, immobilize reactive heavy metals and sequester carbon—effectively providing civil engineering functionality while clarifying the ground water and removing carbon from the atmosphere? Exploration of these ideas has begun in earnest in recent years. This paper explores the potential, challenges and opportunities of this new field, and highlights one biogeochemical function of soil that has shown promise and is developing rapidly as a new technology. The example is used to propose a generalized approach in which the potential of this new field can be fully realized. PMID:20829246

Soil engineering in vivo: harnessing natural biogeochemical systems for sustainable, multi-functional engineering solutions.

PubMed

DeJong, Jason T; Soga, Kenichi; Banwart, Steven A; Whalley, W Richard; Ginn, Timothy R; Nelson, Douglas C; Mortensen, Brina M; Martinez, Brian C; Barkouki, Tammer

2011-01-06

Carbon sequestration, infrastructure rehabilitation, brownfields clean-up, hazardous waste disposal, water resources protection and global warming-these twenty-first century challenges can neither be solved by the high-energy consumptive practices that hallmark industry today, nor by minor tweaking or optimization of these processes. A more radical, holistic approach is required to develop the sustainable solutions society needs. Most of the above challenges occur within, are supported on, are enabled by or grown from soil. Soil, contrary to conventional civil engineering thought, is a living system host to multiple simultaneous processes. It is proposed herein that 'soil engineering in vivo', wherein the natural capacity of soil as a living ecosystem is used to provide multiple solutions simultaneously, may provide new, innovative, sustainable solutions to some of these great challenges of the twenty-first century. This requires a multi-disciplinary perspective that embraces the science of biology, chemistry and physics and applies this knowledge to provide multi-functional civil and environmental engineering designs for the soil environment. For example, can native soil bacterial species moderate the carbonate cycle in soils to simultaneously solidify liquefiable soil, immobilize reactive heavy metals and sequester carbon-effectively providing civil engineering functionality while clarifying the ground water and removing carbon from the atmosphere? Exploration of these ideas has begun in earnest in recent years. This paper explores the potential, challenges and opportunities of this new field, and highlights one biogeochemical function of soil that has shown promise and is developing rapidly as a new technology. The example is used to propose a generalized approach in which the potential of this new field can be fully realized.

Geologic controls of subdivision damage near Denver, Colorado

USGS Publications Warehouse

Noe, D.C.

2005-01-01

This case study investigates the geologic controls on damaging ground deformations in a residential subdivision near Denver, Colo. Moderate to severe damage has occurred in certain areas where linear, parallel heave features with up to 0.3 in (1 ft) of differential displacement have formed across roads and under houses. Other areas have small, localized depressions that have formed in the roadsides with no discernable damage to nearby houses. Still other areas show no evidence of ground movements. The bedrock beneath the subdivision consists of steeply dipping Cretaceous strata of the Benton Shale, Niobrara Formation, and Pierre Shale. Quaternary soil deposits and fill, 0-16 m (0-53 ft) thick, overlie the bedrock. The most pronounced and damaging linear-heave features are coincident with steeply dipping, silty claystone with thin layers of very highly plastic bentonite. These heave features diminish as the depth to bedrock increases, and become small to negligible where the bedrock is overlain by 3 m (10 ft) or more of overburden soil deposits or fill. In contrast, areas having no visible damage and those having localized surface depressions are typically underlain by 1-12 m (3-39 ft) of alluvial-terrace deposits or fill. The depressions appear to have been caused by settlement over improperly filled water-and-sewer line trenches. The overall relationship between geology and ground deformations as seen in this subdivision may be useful for predicting, and thereby reducing, damage for future subdivision projects. Journal of Geotechnical and Geoenvironmental Engineering ?? ASCE.

Soil and surface temperatures at the Viking landing sites

NASA Technical Reports Server (NTRS)

Kieffer, H. H.

1976-01-01

The annual temperature range for the Martian surface at the Viking lander sites is computed on the basis of thermal parameters derived from observations made with the infrared thermal mappers. The Viking lander 1 (VL1) site has small annual variations in temperature, whereas the Viking lander 2 (VL2) site has large annual changes. With the Viking lander images used to estimate the rock component of the thermal emission, the daily temperature behavior of the soil alone is computed over the range of depths accessible to the lander; when the VL1 and VL2 sites were sampled, the daily temperature ranges at the top of the soil were 183 to 263 K and 183 to 268 K, respectively. The diurnal variation decreases with depth with an exponential scale of about 5 centimeters. The maximum temperature of the soil sampled from beneath rocks at the VL2 site is calculated to be 230 K. These temperature calculations should provide a reference for study of the active chemistry reported for the Martian soil.

Soil and surface temperatures at the viking landing sites.

PubMed

Kieffer, H H

1976-12-11

The annual temperature range for the martian surface at the Viking lander sites is computed on the basis of thermal parameters derived from observations made with the infrared thermal mappers. The Viking lander 1 (VL1) site has small annual variations in temperature, whereas the Viking lander 2 (VL2) site has large annual changes. With the Viking lander images used to estimate the rock component of the thermal emission, the daily temperature behavior of the soil alone is computed over the range of depths accessible to the lander; when the VL1 and VL2 sites were sampled, the daily temperature ranges at the top of the soil were 183 to 263 K and 183 to 268 K, respectively. The diurnal variation decreases with depth with an exponential scale of about 5 centimeters. The maximum temperature of the soil sampled from beneath rocks at the VL2 site is calculated to be 230 K. These temperature calculations should provide a reference for study of the active chemistry reported for the martian soil.

Cyclic biogeochemical processes and nitrogen fate beneath a subtropical stormwater infiltration basin

USGS Publications Warehouse

O'Reilly, Andrew M.; Chang, Ni-Bin; Wanielista, Martin P.

2012-01-01

A stormwater infiltration basin in north–central Florida, USA, was monitored from 2007 through 2008 to identify subsurface biogeochemical processes, with emphasis on N cycling, under the highly variable hydrologic conditions common in humid, subtropical climates. Cyclic variations in biogeochemical processes generally coincided with wet and dry hydrologic conditions. Oxidizing conditions in the subsurface persisted for about one month or less at the beginning of wet periods with dissolved O2 and NO3- showing similar temporal patterns. Reducing conditions in the subsurface evolved during prolonged flooding of the basin. At about the same time O2 and NO3- reduction concluded, Mn, Fe and SO42- reduction began, with the onset of methanogenesis one month later. Reducing conditions persisted up to six months, continuing into subsequent dry periods until the next major oxidizing infiltration event. Evidence of denitrification in shallow groundwater at the site is supported by median NO3-–N less than 0.016 mg L-1, excess N2 up to 3 mg L-1 progressively enriched in δ15N during prolonged basin flooding, and isotopically heavy δ15N and δ18O of NO3- (up to 25‰ and 15‰, respectively). Isotopic enrichment of newly infiltrated stormwater suggests denitrification was partially completed within two days. Soil and water chemistry data suggest that a biogeochemically active zone exists in the upper 1.4 m of soil, where organic carbon was the likely electron donor supplied by organic matter in soil solids or dissolved in infiltrating stormwater. The cyclic nature of reducing conditions effectively controlled the N cycle, switching N fate beneath the basin from NO3- leaching to reduction in the shallow saturated zone. Results can inform design of functionalized soil amendments that could replace the native soil in a stormwater infiltration basin and mitigate potential NO3- leaching to groundwater by replicating the biogeochemical conditions under the observed basin.

Precipitation pulses and carbon fluxes in semiarid and arid ecosystems.

PubMed

Huxman, Travis E; Snyder, Keirith A; Tissue, David; Leffler, A Joshua; Ogle, Kiona; Pockman, William T; Sandquist, Darren R; Potts, Daniel L; Schwinning, Susan

2004-10-01

In the arid and semiarid regions of North America, discrete precipitation pulses are important triggers for biological activity. The timing and magnitude of these pulses may differentially affect the activity of plants and microbes, combining to influence the C balance of desert ecosystems. Here, we evaluate how a "pulse" of water influences physiological activity in plants, soils and ecosystems, and how characteristics, such as precipitation pulse size and frequency are important controllers of biological and physical processes in arid land ecosystems. We show that pulse size regulates C balance by determining the temporal duration of activity for different components of the biota. Microbial respiration responds to very small events, but the relationship between pulse size and duration of activity likely saturates at moderate event sizes. Photosynthetic activity of vascular plants generally increases following relatively larger pulses or a series of small pulses. In this case, the duration of physiological activity is an increasing function of pulse size up to events that are infrequent in these hydroclimatological regions. This differential responsiveness of photosynthesis and respiration results in arid ecosystems acting as immediate C sources to the atmosphere following rainfall, with subsequent periods of C accumulation should pulse size be sufficient to initiate vascular plant activity. Using the average pulse size distributions in the North American deserts, a simple modeling exercise shows that net ecosystem exchange of CO2 is sensitive to changes in the event size distribution representative of wet and dry years. An important regulator of the pulse response is initial soil and canopy conditions and the physical structuring of bare soil and beneath canopy patches on the landscape. Initial condition influences responses to pulses of varying magnitude, while bare soil/beneath canopy patches interact to introduce nonlinearity in the relationship between pulse size and soil water response. Building on this conceptual framework and developing a greater understanding of the complexities of these eco-hydrologic systems may enhance our ability to describe the ecology of desert ecosystems and their sensitivity to global change.

Water and nitrogen management effects on water and nitrogen fluxes in Florida Flatwoods.

PubMed

Hendricks, Gregory S; Shukla, Sanjay

2011-01-01

The effects of water and fertilizer best management practices (BMPs) have not been quantified for groundwater nitrogen (N) beneath seepage irrigated vegetable fields with shallow water table environments. This effect was evaluated by a 3-yr study conducted in the Flatwoods of south Florida for watermelon ( cv. Mardi Gras and Tri-X 313) and tomato ( cv. BHN 586) using three treatments of water and inorganic fertilizer N (N) rates: (i) high fertilizer and water rates with seepage irrigation (HR), (ii) recommended fertilizer and water rates (BMP) with seepage irrigation (RR); and (iii) RR with subsurface drip irrigation (RR-SD). These treatments were implemented on six hydraulically isolated plots. The N rate treatments for high (HR) and recommended (RR and RR-SD) were based on a grower survey and BMP recommendations, respectively. Water applied, water table depth, and soil moisture content were regularly monitored for each treatment. Plant, soil, and groundwater N sampling and analyses were conducted for each season of the 3-yr study. The average water applied in HR (187 cm) was greater than RR (172 cm) and RR-SD (94 cm). Soil N maintained in crop beds for HR was significantly higher than RR and RR-SD. Soil solution analyses showed that N leached beneath HR (112 mg L) was greater ( = 0.053) than RR (76 mg L) and RR-SD (88 mg L). Shallow groundwater concentrations of dissolved inorganic nitrogen (NH-N + NO-N) were higher ( = 0.02) in HR (37 mg L) compared with RR (15 mg L) and RR-SD (19 mg L). Decreased N and water table levels can improve groundwater quality by reducing N leachate in shallow water table environments with seepage irrigated vegetable production systems. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Simulation of Groundwater Mounding Beneath Hypothetical Stormwater Infiltration Basins

USGS Publications Warehouse

Carleton, Glen B.

2010-01-01

Groundwater mounding occurs beneath stormwater management structures designed to infiltrate stormwater runoff. Concentrating recharge in a small area can cause groundwater mounding that affects the basements of nearby homes and other structures. Methods for quantitatively predicting the height and extent of groundwater mounding beneath and near stormwater Finite-difference groundwater-flow simulations of infiltration from hypothetical stormwater infiltration structures (which are typically constructed as basins or dry wells) were done for 10-acre and 1-acre developments. Aquifer and stormwater-runoff characteristics in the model were changed to determine which factors are most likely to have the greatest effect on simulating the maximum height and maximum extent of groundwater mounding. Aquifer characteristics that were changed include soil permeability, aquifer thickness, and specific yield. Stormwater-runoff variables that were changed include magnitude of design storm, percentage of impervious area, infiltration-structure depth (maximum depth of standing water), and infiltration-basin shape. Values used for all variables are representative of typical physical conditions and stormwater management designs in New Jersey but do not include all possible values. Results are considered to be a representative, but not all-inclusive, subset of likely results. Maximum heights of simulated groundwater mounds beneath stormwater infiltration structures are the most sensitive to (show the greatest change with changes to) soil permeability. The maximum height of the groundwater mound is higher when values of soil permeability, aquifer thickness, or specific yield are decreased or when basin depth is increased or the basin shape is square (and values of other variables are held constant). Changing soil permeability, aquifer thickness, specific yield, infiltration-structure depth, or infiltration-structure shape does not change the volume of water infiltrated, it changes the shape or height of the groundwater mound resulting from the infiltration. An aquifer with a greater soil permeability or aquifer thickness has an increased ability to transmit water away from the source of infiltration than aquifers with lower soil permeability; therefore, the maximum height of the groundwater mound will be lower, and the areal extent of mounding will be larger. The maximum height of groundwater mounding is higher when values of design storm magnitude or percentage of impervious cover (from which runoff is captured) are increased (and other variables are held constant) because the total volume of water to be infiltrated is larger. The larger the volume of infiltrated water the higher the head required to move that water away from the source of recharge if the physical characteristics of the aquifer are unchanged. The areal extent of groundwater mounding increases when soil permeability, aquifer thickness, design-storm magnitude, or percentage of impervious cover are increased (and values of other variables are held constant). For 10-acre sites, the maximum heights of the simulated groundwater mound range from 0.1 to 18.5 feet (ft). The median of the maximum-height distribution from 576 simulations is 1.8 ft. The maximum areal extent (measured from the edge of the infiltration basins) of groundwater mounding of 0.25-ft ranges from 0 to 300 ft with a median of 51 ft for 576 simulations. Stormwater infiltration at a 1-acre development was simulated, incorporating the assumption that the hypothetical infiltration structure would be a pre-cast concrete dry well having side openings and an open bottom. The maximum heights of the simulated groundwater-mounds range from 0.01 to 14.0 ft. The median of the maximum-height distribution from 432 simulations is 1.0 ft. The maximum areal extent of groundwater mounding of 0.25-ft ranges from 0 to 100 ft with a median of 10 ft for 432 simulations. Simulated height and extent of groundwater mounding associ

ROBERT BOBO AND MIKE NICHOLS AT TEST STAND 4693

NASA Image and Video Library

2016-12-14

ROBERT BOBO, LEFT, AND MIKE NICHOLS TALK BENEATH THE 221-FOOT-TALL TEST STAND 4693, THE LARGEST OF TWO NEW SPACE LAUNCH SYSTEM TEST STANDS AT MSFC. BOBO MANAGES SLS STRUCTURAL STRENGTH TESTING, AND NICHOLS IS LEAD TEST ENGINEER FOR THE SLS LIQUID HYDROGEN TANK.

KSC-07pd1343

NASA Image and Video Library

2007-06-04

KENNEDY SPACE CENTER, FLA. -- In the Payload Handling Servicing Facility, the Phoenix spacecraft is being rotated for center of gravity determination. The Phoenix mission is the first project in NASA's first openly competed program of Mars Scout missions. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. It will serve as NASA's first exploration of a potential modern habitat on Mars and open the door to a renewed search for carbon-bearing compounds, Photo credit: NASA/George Shelton

Survival of Salmonella adelaide and fecal coliforms in coarse sands of the swan costal plain, Western Australia.

PubMed Central

Parker, W F; Mee, B J

1982-01-01

The survival of Salmonella adelaide and fecal coliforms in two coarse sands influenced by two sources of septic tank effluent was studied. The experiments were conducted in conditions that reflected the soil environment beneath functioning septic tank systems. Significant differences in survival were found with different effluent sources. In one experiment the survival of S. adelaide was similar to that of fecal coliforms; in the other it was not. The nonuniform, multiphasic nature of survival curves was variability observed in these experiments suggests that the application of such survival data for establishing management criteria for septic tank systems--by, for example, the use of soil moisture characteristic curves to give estimates of movement in the soil--is inappropriate. PMID:7103482

KSC-07pd1344

NASA Image and Video Library

2007-06-04

KENNEDY SPACE CENTER, FLA. -- In the Payload Handling Servicing Facility, the Phoenix spacecraft is being rotated for center of gravity determination. The Phoenix mission is the first project in NASA's first openly competed program of Mars Scout missions. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. It will serve as NASA's first exploration of a potential modern habitat on Mars and open the door to a renewed search for carbon-bearing compounds, Photo credit: NASA/George Shelton

KSC-07pd1342

NASA Image and Video Library

2007-06-04

KENNEDY SPACE CENTER, FLA. -- In the Payload Handling Servicing Facility, the Phoenix spacecraft is being rotated for center of gravity determination. The Phoenix mission is the first project in NASA's first openly competed program of Mars Scout missions. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. It will serve as NASA's first exploration of a potential modern habitat on Mars and open the door to a renewed search for carbon-bearing compounds, Photo credit: NASA/George Shelton

KSC-07pd1561

NASA Image and Video Library

2007-06-19

KENNEDY SPACE CENTER, FLA. -- On Pad 17-A at Cape Canaveral Air Force Station, one solid rocket booster is lifted into the mobile service tower while another, below, is raised from its transporter. The SRBs will be mated with the Delta II first stage. The Delta is the launch vehicle for the Phoenix Mars Lander spacecraft. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Phoenix is scheduled to launch Aug. 3. Photo credit: NASA/Kim Shiflett

Heavy metals in bark of Pinus massoniana (Lamb.) as an indicator of atmospheric deposition near a smeltery at Qujiang, China.

PubMed

Kuang, Yuan Wen; Zhou, Guo Yi; Da Wen, Zhi; Liu, Shi Zhong

2007-06-01

Rapid urbanization and the expansion of industrial activities in the past several decades have led to large increases in emissions of pollutants in the Pearl River Delta of south China. Recent reports have suggested that industrial emission is a major factor contributing to the damages in current natural ecosystem in the Delta area. Tree barks have been used successfully to monitor the levels of atmospheric metal deposition in many areas, but rarely in China. This study aimed at determining whether atmospheric heavy metal deposition from a Pb-Zn smeltery at Qujiang, Guangdong province, could be accurately reflected both in the inner bark and the outer bark of Masson pine (Pinus massoniana L.). The impact of the emission from smeltery on the soils beneath the trees and the relationships of the concentrations between the soils and the barks were also analyzed. Barks around the bole of Pinus massoniana from a pine forest near a Pb-Zn smeltery at Qujiang and a reference forest at Dinghushan natural reserve were sampled with a stainless knife at an average height of 1.5 m above the ground. Mosses and lichens on the surface barks were cleaned prior to sampling. The samples were carefully divided into the inner bark (living part) and the outer bark (dead part) in the laboratory, and dried and ground, respectively. After being dry-ashed, the powder of the barks was dissolved in HNO3. The solutions were analyzed for iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), chromium (Cr), nickel (Ni) and cobalt (Co) by inductively coupled plasmas emission spectrometry (ICP, PS-1000AT, USA) and Cadmium (Cd) and lead (Pb) by graphite furnace atomic absorption spectrometry (GFAAS, ZEENIT 60, Germany). Surface soils (0-10 cm) beneath the sample trees were also collected and analyzed for the selected metals. Concentrations of the selected metals in soils at Qujiang were far above their environmental background values in the area, except for Fe and Mn, whilst at Dinghushan, they were far below their background values, except for Cd and Co. Levels of the metals, in particular Pb and Zn, in the soils beneath the sample trees at Qujiang were higher than those at Dinghushan with statistical significance. The result suggested that the pine forest soils at Qujiang had a great input of heavy metals from wet and dry atmospheric deposition, with the Pb-Zn smeltery most probably being the source. Levels of Cu, Fe, Mn, Zn, Ni and Pb at Qujiang, both in the inner and the outer bark, were statistically higher than those at Dinghushan. Higher concentrations of Pb, Fe, Zn and Cu may come from the stem-flow of elements leached from the canopy, soil splash on the 1.5 m height and sorption of metals in the mosses and lichens growing on the bark, which were direct or indirect results from the atmospheric deposition. Levels of heavy metals in the outer barks were associated well with the metal concentrations in the soil, reflecting the close relationships between the metal atmospheric deposition and their accumulation in the outer bark of Masson pine. The significant (p<0.01) correlations of Fe-Cu, Fe-Cr, Fe-Pb, Fe-Ni, Pb-Ni, and Pb-Zn in the outer barks at Qujiang again suggested a common source for the metals. The correlation only occurred between Pb and Ni, Cd and Co in the outer barks at Dinghushan, which suggested that those metals must possibly have other uncommon sources. Atmospheric deposition of the selected metals was great at Qujiang, based on the levels in the bark of Pinus massoniana and on the concentrations in the soils beneath the trees compared with that at Dinghushan. Bark of Pinus massoniana, especially the outer bark, was an indicator of metal loading at least at the time of sampling. The results from this study and the techniques employed constituted a new contribution to the development of biogeochemical methods for environmental monitoring particularly in areas with high frequency of pollution in China. The method would be of value for follow up studies aimed at the assessment of industrial pollution in other areas similar with the Pearl River Delta.

Alder (Alnus crispa) effects on soils in ecosystems of the Agashashok River valley, northwest Alaska

USGS Publications Warehouse

Rhoades, Charles; Oskarsson, Hlynur; Binkley, Dan; Stottlemeyer, Robert

2001-01-01

At the northern limit of the boreal forest biome, alder (Alnus crispa [Ait.] Pursh) shrubs occur in a variety of ecosystems. We assessed the effects of individual alder shrubs on soil properties and understory plant tissue nitrogen in floodplain terraces, valley slopes and tussock tundra ridges. The three ecosystems differed with respect to soil properties and abiotic conditions and supported distinct plant communities. Alder increased resin-exchangeable soil N and NO3 production significantly in each ecosystem. The greatest difference between alder canopy and surrounding soil NO3 measured both under field and laboratory conditions occurred in floodplain sites. The shrub effect on soil pH and soil organic matter was greatest on tundra ridges. Alder shrubs also influenced the nitrogen nutrition of plants growing beneath their canopies. Plants growing below alder canopies had higher foliar nitrogen concentration and natural abundance 15N composition and lower carbon to nitrogen ratio than open-grown plants. Similar to soil N availability, understory plant leaf chemistry responded more to alder on floodplains than on slope or tundra ecosystems. This pattern suggests that understory plants rely more heavily on alder-fixed-N in this resource-poor ecosystem.

Detection of decomposition volatile organic compounds in soil following removal of remains from a surface deposition site.

PubMed

Perrault, Katelynn A; Stefanuto, Pierre-Hugues; Stuart, Barbara H; Rai, Tapan; Focant, Jean-François; Forbes, Shari L

2015-09-01

Cadaver-detection dogs use volatile organic compounds (VOCs) to search for human remains including those deposited on or beneath soil. Soil can act as a sink for VOCs, causing loading of decomposition VOCs in the soil following soft tissue decomposition. The objective of this study was to chemically profile decomposition VOCs from surface decomposition sites after remains were removed from their primary location. Pig carcasses were used as human analogues and were deposited on a soil surface to decompose for 3 months. The remains were then removed from each site and VOCs were collected from the soil for 7 months thereafter and analyzed by comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOFMS). Decomposition VOCs diminished within 6 weeks and hydrocarbons were the most persistent compound class. Decomposition VOCs could still be detected in the soil after 7 months using Principal Component Analysis. This study demonstrated that the decomposition VOC profile, while detectable by GC×GC-TOFMS in the soil, was considerably reduced and altered in composition upon removal of remains. Chemical reference data is provided by this study for future investigations of canine alert behavior in scenarios involving scattered or scavenged remains.

A late-Holocene surficial sandblow in the western lowlands of southeast Missouri: A paleoseismic milestone

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

Vaughn, J.D.; Hoffman, D.; Palmer, J.R.

1993-03-01

Shallow trenches excavated across an elongate mound of sand showed several characteristics consistent with an extrusive paleoearthquake origin. Numerous clastic dikes, sills, and intruded cavities immediately underlie the sandblow; and discontinuous eruptive vents and occasional small clasts were located within the sandblow. An adjacent ditch exposure indicates that the sandblow formed by the venting of sand up through seven or more meters of fine-grained alluvium--a likely result of seismic liquefaction. Soil-morphological characteristics which suggest a prehistoric age include: (1) dominant yellowish brown Munsell color (10YR 5/4 and 5/6) beneath the A horizon of the sandblow, (2) absence of bedding planesmore » in the sandblow, and (3) absence of a buried A horizon immediately beneath the sandblow. In contrast, sandblows produced by the great 1811--12 New Madrid earthquakes are typically dull colored, often have traces of bedding just under the A horizon, and are intermittently underlain by buried A horizons of the pre-earthquake surface soils. Formation of this prehistoric sandblow may have occurred contemporaneously with paleoliquefaction and tectonic deformation previously identified by others in the vicinity of New Madrid, Mo. A calibrated [sup 14]C date of 770--1020 A.D. on wood obtained just beneath the sandblow overlaps considerably a calibrated paleoearthquake timing of 539--991 A.D. for a site 30 km northeast of New Madrid. Assuming that these data represent the same event and that the seismic source was near New Madrid, the 60--70 km epicentral distance to this large sandblow in the Western Lowlands suggests a paleoearthquake magnitude of about 7.0 or greater.« less

Nebraska's groundwater legacy: Nitrate contamination beneath irrigated cropland

PubMed Central

Exner, Mary E; Hirsh, Aaron J; Spalding, Roy F

2014-01-01

A 31 year record of ∼44,000 nitrate analyses in ∼11,500 irrigation wells was utilized to depict the decadal expansion of groundwater nitrate contamination (N ≥ 10 mg/L) in the irrigated corn-growing areas of eastern and central Nebraska and analyze long-term nitrate concentration trends in 17 management areas (MAs) subject to N fertilizer and budgeting requirements. The 1.3 M contaminated hectares were characterized by irrigation method, soil drainage, and vadose zone thickness and lithology. The areal extent and growth of contaminated groundwater in two predominately sprinkler-irrigated areas was only ∼20% smaller beneath well-drained silt loams with thick clayey-silt unsaturated layers and unsaturated thicknesses >15 m (400,000 ha and 15,000 ha/yr) than beneath well and excessively well-drained soils with very sandy vadose zones (511,000 ha and 18,600 ha/yr). Much slower expansion (3700 ha/yr) occurred in the 220,000 contaminated hectares in the central Platte valley characterized by predominately gravity irrigation on thick, well-drained silt loams above a thin (∼5.3 m), sandy unsaturated zone. The only reversals in long-term concentration trends occurred in two MAs (120,500 ha) within this contaminated area. Concentrations declined 0.14 and 0.20 mg N/L/yr (p < 0.02) to ∼18.3 and 18.8 mg N/L, respectively, during >20 years of management. Average annual concentrations in 10 MAs are increasing (p < 0.05) and indicate that average nitrate concentrations in leachates below the root zone and groundwater concentrations have not yet reached steady state. While management practices likely have slowed increases in groundwater nitrate concentrations, irrigation and nutrient applications must be more effectively controlled to retain nitrate in the root zone. PMID:25558112

Development of a Dynamic Visco-elastic Vehicle-Soil Interaction Model for Rut Depth, and Power Determinations

DTIC Science & Technology

2011-09-06

Presentation Outline A) Review of Soil Model governing equations B) Development of pedo -transfer functions (terrain database to engineering properties) C...lateral earth pressure) UNCLASSIFIED B) Development of pedo -transfer functions Engineering parameters needed by soil model - compression index - rebound...inches, RCI for fine- grained soils, CI for coarse-grained soils. UNCLASSIFIED Pedo -transfer function • Need to transfer existing terrain database

Seasonal change in precipitation, snowpack, snowmelt, soil water and streamwater chemistry, northern Michigan

USGS Publications Warehouse

Stottlemyer, R.; Toczydlowski, D.

1999-01-01

We have studied weekly precipitation, snowpack, snowmelt, soil water and streamwater chemistry throughout winter for over a decade in a small (176 ha) northern Michigan watershed with high snowfall and vegetated by 60 to 80 year-old northern hardwoods. In this paper, we examine physical, chemical, and biological processes responsible for observed seasonal change in streamwater chemistry based upon intensive study during winter 1996-1997. The objective was to define the contributions made to winter and spring streamwater chemical concentration and flux by processes as snowmelt, over-winter forest floor and surface soil mineralization, immobilization, and exchange, and subsurface flowpath. The forest floor and soil were unfrozen beneath the snowpack which permitted most snowmelt to enter. Over-winter soil mineralization and other biological processes maintain shallow subsurface ion and dissolved organic carbon (DOC) reservoirs. Small, but steady, snowmelt throughout winter removed readily mobilized soil NO3- which resulted in high over-winter streamwater concentrations but little flux. Winter soil water levels and flowpaths were generally deep which increased soil water and streamwater base cation (C(B)), HCO3-, and Si concentrations. Spring snowmelt increased soil water levels and removal of ions and DOC from the biologically active forest floor and shallow soils. The snowpack solute content was a minor component in determining streamwater ion concentration or flux during and following peak snowmelt. Exchangeable ions, weakly adsorbed anions, and DOC in the forest floor and surface soils dominated the chemical concentration and flux in soil water and streamwater. Following peak snowmelt, soil microbial immobilization and rapidly increased plant uptake of limiting nutrients removed nearly all available nitrogen from soil water and streamwater. During the growing season high evapotranspiration increased subsurface flowpath depth which in turn removed weathering products, especially C(B), HCO3-, and Si, from deeper soils. Soil water was a major component in the hydrologic and chemical budgets.We have studied weekly precipitation, snowpack, snowmelt, soil water and streamwater chemistry throughout winter for over a decade in a small (176 ha) northern Michigan watershed with high snowfall and vegetated by 60 to 80 year-old northern hardwoods. In this paper, we examine physical, chemical, and biological processes responsible for observed seasonal change in streamwater chemistry based upon intensive study during winter 1996-1997. The objective was to define the contributions made to winter and spring streamwater chemical concentration and flux by processes as snowmelt, over-winter forest floor and surface soil mineralization, immobilization, and exchange, and subsurface flowpath. The forest floor and soils were unfrozen beneath the snowpack which permitted most snowmelt to enter. Over-winter soil mineralization and other biological processes maintain shallow subsurface ion and dissolved organic carbon (DOC) reservoirs. Small, but steady, snowmelt throughout winter removed readily mobilized soil NO3- which resulted in high over-winter streamwater concentrations but little flux. Winter soil water levels and flowpaths were generally deep which increased soil water and streamwater base cation (CB), HCO3-, and Si concentrations. Spring snowmelt increased soil water levels and removal of ions and DOC from the biologically active forest floor and shallow soils. The snowpack solute content was a minor component in determining streamwater ion concentration or flux during and following peak snowmelt. Exchangeable ions, weakly adsorbed anions, and DOC in the forest floor and surface soils dominated the chemical concentration and flux in soil water and streamwater. Following peak snowmelt, soil microbial immobilization and rapidly increased plant uptake of limiting nutrients removed nearly all available nitrogen from soil water and streamwater. D

A reservoir of nitrate beneath desert soils.

PubMed

Walvoord, Michelle A; Phillips, Fred M; Stonestrom, David A; Evans, R Dave; Hartsough, Peter C; Newman, Brent D; Striegl, Robert G

2003-11-07

A large reservoir of bioavailable nitrogen (up to approximately 10(4) kilograms of nitrogen per hectare, as nitrate) has been previously overlooked in studies of global nitrogen distribution. The reservoir has been accumulating in subsoil zones of arid regions throughout the Holocene. Consideration of the subsoil reservoir raises estimates of vadose-zone nitrogen inventories by 14 to 71% for warm deserts and arid shrublands worldwide and by 3 to 16% globally. Subsoil nitrate accumulation indicates long-term leaching from desert soils, impelling further evaluation of nutrient dynamics in xeric ecosystems. Evidence that subsoil accumulations are readily mobilized raises concern about groundwater contamination after land-use or climate change.

A reservoir of nitrate beneath desert soils

USGS Publications Warehouse

Walvoord, Michelle Ann; Phillips, Fred M.; Stonestrom, David A.; Evans, R. Dave; Hartsough, Peter C.; Newman, Brent D.; Striegl, Robert G.

2003-01-01

A large reservoir of bioavailable nitrogen (up to ∼104 kilograms of nitrogen per hectare, as nitrate) has been previously overlooked in studies of global nitrogen distribution. The reservoir has been accumulating in subsoil zones of arid regions throughout the Holocene. Consideration of the subsoil reservoir raises estimates of vadose-zone nitrogen inventories by 14 to 71% for warm deserts and arid shrublands worldwide and by 3 to 16% globally. Subsoil nitrate accumulation indicates long-term leaching from desert soils, impelling further evaluation of nutrient dynamics in xeric ecosystems. Evidence that subsoil accumulations are readily mobilized raises concern about groundwater contamination after land-use or climate change.

The persistence of human DNA in soil following surface decomposition.

PubMed

Emmons, Alexandra L; DeBruyn, Jennifer M; Mundorff, Amy Z; Cobaugh, Kelly L; Cabana, Graciela S

2017-09-01

Though recent decades have seen a marked increase in research concerning the impact of human decomposition on the grave soil environment, the fate of human DNA in grave soil has been relatively understudied. With the purpose of supplementing the growing body of literature in forensic soil taphonomy, this study assessed the relative persistence of human DNA in soil over the course of decomposition. Endpoint PCR was used to assess the presence or absence of human nuclear and mitochondrial DNA, while qPCR was used to evaluate the quantity of human DNA recovered from the soil beneath four cadavers at the University of Tennessee's Anthropology Research Facility (ARF). Human nuclear DNA from the soil was largely unrecoverable, while human mitochondrial DNA was detectable in the soil throughout all decomposition stages. Mitochondrial DNA copy abundances were not significantly different between decomposition stages and were not significantly correlated to soil edaphic parameters tested. There was, however, a significant positive correlation between mitochondrial DNA copy abundances and the human associated bacteria, Bacteroides, as estimated by 16S rRNA gene abundances. These results show that human mitochondrial DNA can persist in grave soil and be consistently detected throughout decomposition. Copyright © 2017 The Chartered Society of Forensic Sciences. Published by Elsevier B.V. All rights reserved.

Superfund Record of Decision (EPA Region 5): New Brighton/Arden Hills (TCAAP), Twin Cities Army Ammunition Plant, MN. (Seventh remedial action), August 1989

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

Not Available

1989-08-11

The New Brighton/Arden Hills site, also known as the Twin Cities Army Ammunition Plant (TCAAP) site, is in New Brighton, Minnesota. Past disposal of ammunition manufacturing wastes onsite resulted in contamination of ground water beneath and downgradient of the site. A total of 14 waste-disposal locations have been identified and assigned as Sites A through K. During remedial investigations at Site D, soil was discovered to be contaminated with PCBs and other organic and metal contaminants. A soil-gas extraction system was implemented to remove the source of volatile organic contamination and reduce the potential of migration to ground water. Inmore » implementing the soil gas extraction system, PCB-contaminated soil was removed, stockpiled near Site D, and sealed with a plastic-liner material. The interim remedy addresses the treatment and disposal of contaminated soil that is stockpiled near Site D. The primary contaminants of concern affecting the soil are VOCs including TCE and PCE, other organics including PCBs, and metals including arsenic and lead.« less

Movements of water, solutes, and stable isotopes in the unsaturated zones of two sand plains in the upper Midwest

USGS Publications Warehouse

Komor, Stephen C.; Emerson, Douglas G.

1994-01-01

Four month-long field experiments investigated movements of water and solutes through unsaturated sand plains near Princeton, Minnesota, and Oakes, North Dakota. Atrazine and bromide were applied to bare soils and soils planted with corn. The field plots were irrigated according to local farming practices. At the end of each experiment, unsaturated soils were analyzed for atrazine and bromide concentrations and oxygen and hydrogen isotope compositions of soil water. Most soil water was affected by evaporation but groundwater beneath the plots had no evaporative isotopic signature. Therefore most recharge consisted of water that was unaffected by evaporation. Sources of such water may have included snowmelt, prolonged or high-intensity rainfalls that were not interrupted by periods of drying, and water that moved through preferential flow paths. Preferential flow also was suggested by the detection of atrazine, deethylatrazine, and bromide in groundwater shortly after each application of irrigation water at Princeton and by isolated concentrations of atrazine and bromide in soil well below the main masses of chemicals at Oakes.

Luminescence petrography of lunar samples

NASA Technical Reports Server (NTRS)

1972-01-01

Light-colored metaclastic rock fragments, mainly anorthositic breccias, are dominant in the lithic clasts of rock 14321 and constitute about 25% of the Apollo 14 soils. Concentration of anorthositic breccias is less in the Apollo 15 soils, but is higher in the Front samples. The Rille edge soils are rich in basalt fragments. The Apollo 15 soils are also rich in green glasses. True anorthosites in the Hadley region were found only at the St. George Crater site. Varying degrees of metamorphism were found in the anorthositic fragments, and luminescence zonations give independent evidence of metamorphism. Compositional zoning verifies the interpretation of luminescence. Rock 14321 gives evidence of modest annealing, but the light metaclastic fragments were metamorphosed before incorporation into the rock. Reaction rimming on plagioclase results in mosaicism and preferentially affects grains. The spectral analysis of luminescence in plagioclase shows that a red-infrared emission band is present in a small fraction of plagioclase grains. Samples from trench bottoms and from beneath a large boulder were compared with surface samples. Large variations in soil composition indicate marked layering in the Apollo 15 soils.

Mercury bio-extraction by fungus Coprinus comatus: a possible bioindicator and mycoremediator of polluted soils?

PubMed

Falandysz, Jerzy

2016-04-01

The Shaggy Ink Cap (Coprinus comatus), which is a common in wild in northern hemisphere was examined in field for potential to be used as possible bio-extractor of Hg from polluted grounds but also as possible bioindicator of urban soils (roadside, barren lands, lawns) pollution with Hg. The contents of Hg in caps and stipes of C. comatus from the grounds examined in this study correlated positively with the levels of soil contamination. Analysis of sets of data available worldwide on Hg in C. comatus and soils beneath-fruiting bodies showed on a positive correlation between degree of soil and mushroom contamination. Hence, C. comatus could be considered as a sensitive species and with bioindication and bioremediation potency for soils polluted with Hg in further studies. Young-fruiting bodies of C. comatus are edible and considered excellent if consumed soon after pick-up. Eating them when foraged from the urban places can provide to a consumer Hg at relatively high dose, while unresolved question is absorption rate of Hg compounds contained in ingested mushroom meal.

Review of Thermosyphon Applications

DTIC Science & Technology

2014-02-11

method (Johnston 1981) is typically used to protect permafrost. A passive method maintains the frozen state of the soil. The most widely used passive...technique is to incorporate ventilated air spaces beneath elevated buildings (Shur and Goering 2009). This method is recommended for locations with...permafrost temperatures be- low –3°C (Johnston 1981) and provides a measure of thermal stability. Ac- tive methods concentrate on removing the thaw

Groundwater impact assessment for the 216-U-17 Crib, 200 West Area

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

Reidel, S.P.; Johnson, V.G.; Kline, N.W.

1993-06-01

As required by the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement milestone M-17-00A), this report assesses the impact to groundwater from discharge of process condensate to the ground at the 216-U-17 Crib. The assessment considers impacts associated with moisture movement through soil beneath the crib and the potential transport of contaminants to the groundwater.

Controls on the methane released through ebullition affected by permafrost degradation

Treesearch

S.J. Klapstein; M.R. Turetsky; A.D. McGuire; J.W. Harden; C.I. Czimczik; X. Xu; J.P. Chanton; J.M. Waddington

2014-01-01

Permafrost thaw in peat plateaus leads to the flooding of surface soils and the formation of collapse scar bogs, which have the potential to be large emitters of methane (CH4) from surface peat as well as deeper, previously frozen, permafrost carbon (C). We used a network of bubble traps, permanently installed 20 cm and 60 cm beneath the moss surface, to examine...

IN-SITU AIR INJECTION, SOIL VACUUM EXTRACTION AND ENHANCED BIODEGRADATION: A CASE STUDY IN A JP-4 JET FUEL CONTAMINATED SITE

EPA Science Inventory

The U.S. Environmental Protection Agency (U.S. EPA) and the U.S. Coast Guard (USCG) conducted a joint demonstration of in situ remediation of a JP-4 jet fuel spill at the USCG Support Center in Elizabeth City, North Carolina. The jet fuel was trapped beneath a clay layer that ext...

Characteristics and engineering properties of the soft soil layer in highway soil subgrades.

DOT National Transportation Integrated Search

2006-06-01

The objective of this research was to examine the conditions and characteristics of soil subgrades that had been stabilized using mechanical compaction. Goals of the study are to identify and examine the engineering properties and behavior of the ...

2D soil and engineering-seismic bedrock modeling of eastern part of Izmir inner bay/Turkey

NASA Astrophysics Data System (ADS)

Pamuk, Eren; Akgün, Mustafa; Özdağ, Özkan Cevdet; Gönenç, Tolga

2017-02-01

Soil-bedrock models are used as a base when the earthquake-soil common behaviour is defined. Moreover, the medium which is defined as bedrock is classified as engineering and seismic bedrock in itself. In these descriptions, S-wave velocity is (Vs) used as a base. The mediums are called soil where the Vs is < 760 m/s, the bigger ones are called bedrock as well. Additionally, the parts are called engineering bedrock where the Vs is between 3000 m/s and 760 m/s, the parts where are bigger than 3000 m/s called seismic bedrock. The interfacial's horizontal topography where is between engineering and seismic bedrock is effective on earthquake's effect changing on the soil surface. That's why, 2D soil-bedrock models must be used to estimate the earthquake effect that could occur on the soil surface. In this research, surface wave methods and microgravity method were used for occuring the 2D soil-bedrock models in the east of İzmir bay. In the first stage, velocity values were obtained by the studies using surface wave methods. Then, density values were calculated from these velocity values by the help of the empiric relations. 2D soil-bedrock models were occurred based upon both Vs and changing of density by using these density values in microgravity model. When evaluating the models, it was determined that the soil is 300-400 m thickness and composed of more than one layers in parts where are especially closer to the bay. Moreover, it was observed that the soil thickness changes in the direction of N-S. In the study area, geologically, it should be thought the engineering bedrock is composed of Bornova melange and seismic bedrock unit is composed of Menderes massif. Also, according to the geophysical results, Neogene limestone and andesite units at between 200 and 400 m depth show that engineering bedrock characteristic.

Study on Calculation Model of Culvert Soil Pressure

NASA Astrophysics Data System (ADS)

Liu, Jing; Tian, Xiao-yan; Gao, Xiao-mei

2017-09-01

Culvert diseases are prevalent in highway engineering. There are many factors involved in the occurrence of the disease, and the problem is complex. However, the design cannot accurately determine the role of the soil pressure on the culvert is the main reason to the disease. Based on the theoretical analysis and field test, this paper studies the characteristics of the stress and deformation of the culvert-soil structure. According to the theory of soil mechanics, the calculation model of vertical soil pressure at the top of culvert is determined, and the formula of vertical soil pressure at the top of culvert is deduced. Through the field test of the vertical soil pressure at the top of culvert of several engineering examples, the calculation formula of this paper is verified, which can provide reference for future practical engineering.

HOT CELL BUILDING, TRA632, INTERIOR. CONTEXTUAL VIEW OF HOT CELL ...

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

HOT CELL BUILDING, TRA-632, INTERIOR. CONTEXTUAL VIEW OF HOT CELL NO. 2 FROM STAIRWAY ALONG NORTH WALL. OBSERVATION WINDOW ALONG WEST SIDE BENEATH "CELL 2" SIGN. DOORWAY IN LEFT OF VIEW LEADS TO CELL 1 WORK AREA OR TO EXIT OUTDOORS TO NORTH. RADIATION DETECTION MONITOR TO RIGHT OF DOOR. CAMERA FACING SOUTHWEST. INL NEGATIVE NO. HD46-28-3. Mike Crane, Photographer, 2/2005 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

Earthworms as ecosystem engineers and the most important detritivors in forest soils.

PubMed

Kooch, Yahya; Jalilvand, Hamid

2008-03-15

Earthworms are considered as soil engineers because of their effects on soil properties and their influence on the availability of resources for other organisms, including microorganisms and plants. However, the links between their impacts on the soil environment and the resulting modification of natural selection pressures on engineer as well as on other organisms have received little attention. Earthworms are known to have a positive influence on the soil fabric and on the decomposition and mineralization of litter by breaking down organic matter and producing large amounts of fasces, thereby mixing litter with the mineral soil. Therefore, they play an important part in changes from one humus from to another according to forest succession patterns. Consequently, they are also expected to be good bio-indicators for forest site quality and are thus useful when planning forest production improvement. Earthworm's populations are as indicator that in exploited regions is destruction indicator and reclamation plans is nature return indicator. In this study we summarized the current knowledge in relation to earthworm's ecology in forest soils as ecosystem engineers.

Preoperational Subsurface Conditions at the Idaho Nuclear Technology and Engineering Center Service Waste Disposal Facility

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

Ansley, Shannon Leigh

2002-02-01

The Idaho Nuclear Technology and Engineering Center (INTEC) Service Wastewater Discharge Facility replaces the existing percolation ponds as a disposal facility for the INTEC Service Waste Stream. A preferred alternative for helping decrease water content in the subsurface near INTEC, closure of the existing ponds is required by the INTEC Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Record of Decision (ROD) for Waste Area Group 3 Operable Unit 3-13 (DOE-ID 1999a). By August 2002, the replacement facility was constructed approximately 2 miles southwest of INTEC, near the Big Lost River channel. Because groundwater beneath the Idaho National Engineering andmore » Environmental Laboratory (INEEL) is protected under Federal and State of Idaho regulations from degradation due to INEEL activities, preoperational data required by U.S. Department of Energy (DOE) Order 5400.1 were collected. These data include preexisting physical, chemical, and biological conditions that could be affected by the discharge; background levels of radioactive and chemical components; pertinent environmental and ecological parameters; and potential pathways for human exposure or environmental impact. This document presents specific data collected in support of DOE Order 5400.1, including: four quarters of groundwater sampling and analysis of chemical and radiological parameters; general facility description; site specific geology, stratigraphy, soils, and hydrology; perched water discussions; and general regulatory requirements. However, in order to avoid duplication of previous information, the reader is directed to other referenced publications for more detailed information. Documents that are not readily available are compiled in this publication as appendices. These documents include well and borehole completion reports, a perched water evaluation letter report, the draft INEEL Wellhead Protection Program Plan, and the Environmental Checklist.« less

Throughfall and its spatial variability beneath xerophytic shrub canopies within water-limited arid desert ecosystems

NASA Astrophysics Data System (ADS)

Zhang, Ya-feng; Wang, Xin-ping; Hu, Rui; Pan, Yan-xia

2016-08-01

Throughfall is known to be a critical component of the hydrological and biogeochemical cycles of forested ecosystems with inherently temporal and spatial variability. Yet little is understood concerning the throughfall variability of shrubs and the associated controlling factors in arid desert ecosystems. Here we systematically investigated the variability of throughfall of two morphological distinct xerophytic shrubs (Caragana korshinskii and Artemisia ordosica) within a re-vegetated arid desert ecosystem, and evaluated the effects of shrub structure and rainfall characteristics on throughfall based on heavily gauged throughfall measurements at the event scale. We found that morphological differences were not sufficient to generate significant difference (P < 0.05) in throughfall between two studied shrub species under the same rainfall and meteorological conditions in our study area, with a throughfall percentage of 69.7% for C. korshinskii and 64.3% for A. ordosica. We also observed a highly variable patchy pattern of throughfall beneath individual shrub canopies, but the spatial patterns appeared to be stable among rainfall events based on time stability analysis. Throughfall linearly increased with the increasing distance from the shrub base for both shrubs, and radial direction beneath shrub canopies had a pronounced impact on throughfall. Throughfall variability, expressed as the coefficient of variation (CV) of throughfall, tended to decline with the increase in rainfall amount, intensity and duration, and stabilized passing a certain threshold. Our findings highlight the great variability of throughfall beneath the canopies of xerophytic shrubs and the time stability of throughfall pattern among rainfall events. The spatially heterogeneous and temporally stable throughfall is expected to generate a dynamic patchy distribution of soil moisture beneath shrub canopies within arid desert ecosystems.

Land Retirement as a Habitat Restoration Tool

NASA Astrophysics Data System (ADS)

Singh, P. N.; Wallender, W. W.

2007-12-01

Use of intensive irrigation in arid and semi-arid areas usually leads to gradual salination of the soil leading to crop yield decline. The salination problem is mitigated by applying irrigation in excess of crop requirements, which leaches the excess salt load to the groundwater. Insufficient natural or man made drainage to dispose off this saline recharge to the groundwater leads to a gradual rise in the water table and eventual encroachment upon the root zone. This may ultimately make the land unfit for any economically productive activity. The abandoned land may even lead to desertification with adverse environmental consequences. In drainage basins with no surface outflow (sometimes called closed basins), land retirement has been proposed as a management tool to address this problem. Land retirement essentially entails intentionally discontinuing irrigation of selected farmlands with the expectation that the shallow water table beneath those lands should drop and the root zone salinity level should decrease. In the San Joaquin Valley of California, intensive irrigation in conjunction with a shallow underlying layer of clay, known as the Corcoran clay layer and absence of a drainage system caused the root zone to become highly saline and the shallow water table to rise. Land retirement would remove from production those farmlands contributing the poorest quality subsurface drain water. Based on numerical models results, it was expected that with land retirement of substantial irrigated lands with poor drainage characteristics, beneath which lies shallow groundwater with high salt load, the shallow water table beneath those lands should drop. A part of the retired lands could also be used for wildlife habitat. A potential negative side of the land retirement option that has to be considered is that in certain enabling evapotranspiration, soil and water table conditions, water will be drawn upwards and evaporated, leaving a deposit of salts on the surface and in the root zone. Salt on the surface may then be wind blown to adjacent areas creating a potential environmental hazard. Using field results from the U.S. Department of the Interior Land Retirement Demonstration Project at the Tranquillity site located in western Fresno County, principles of mass balance in a fixed control volume, the HYDRUS-1D Software Package for Simulating the One-Dimensional Movement of Water, Heat, and Multiple Solutes in Variably-Saturated Media, and PEST, a model-independent parameter optimizer, we have investigated the processes of soil water and salinity movement in the root zone and the deep vadose zone. Various combinations of evapotranspiration, soil water retention properties, water table condition and top and bottom boundary condition were tested. We show that certain Land Retirement scenarios decrease shallow water table and soil water salinity and enhance development of native plants as a means to facilitate habitat restoration for certain combination of soil and bottom boundary condition. Other combinations are not sustainable.

DECOMPOSTION OF GENETICALLY ENGINEERED TOBACCO UNDER FIELD CONDITIONS: PERSISTENCE OF THE PROTEINASE INHIBITOR I PRODUCT AND EFFECTS OF SOIL MICROBIAL RESPIRATION AND PROTOZOA, NEMATODE AND MICROARTHR

EPA Science Inventory

1. To evaluate the potential effects of genetically engineered (transgenic) plants on soil ecosystems, litterbags containing leaves of non-engineered (parental) and transgenic tobacco plants were buried in field plots. The transgenic tobacco plants were genetically engineered to ...

Seismic behavior of breakwaters on complex ground by numerical tests: Liquefaction and post liquefaction ground settlements

NASA Astrophysics Data System (ADS)

Gu, Linlin; Zhang, Feng; Bao, Xiaohua; Shi, Zhenming; Ye, Guanlin; Ling, Xianzhang

2018-04-01

A large number of breakwaters have been constructed along coasts to protect humans and infrastructures from tsunamis. There is a risk that foundation soils of these structures may liquefy, or partially liquefy during the earthquake preceding a tsunami, which would greatly reduce the structures' capacity to resist the tsunami. It is necessary to consider not only the soil's liquefaction behavior due to earthquake motions but also its post-liquefaction behavior because this behavior will affect the breakwater's capacity to resist an incoming tsunami. In this study, numerical tests based on a sophisticated constitutive model and a soil-water coupled finite element method are used to predict the mechanical behavior of breakwaters and the surrounding soils. Two real breakwaters subjected to two different seismic excitations are examined through numerical simulation. The simulation results show that, earthquakes affect not only the immediate behavior of breakwaters and the surrounding soils but also their long-term settlements due to post-earthquake consolidation. A soil profile with thick clayey layers beneath liquefied soil is more vulnerable to tsunami than a soil profile with only sandy layers. Therefore, quantitatively evaluating the seismic behavior of breakwaters and surrounding soils is important for the design of breakwater structures to resist tsunamis.

Geotechnical engineering in US elementary schools

NASA Astrophysics Data System (ADS)

Suescun-Florez, Eduardo; Iskander, Magued; Kapila, Vikram; Cain, Ryan

2013-06-01

This paper reports on the results of several geotechnical engineering-related science activities conducted with elementary-school students. Activities presented include soil permeability, contact stress, soil stratigraphy, shallow and deep foundations, and erosion in rivers. The permeability activity employed the LEGO NXT platform for data acquisition, the soil profile and foundations activity employed natural and transparent soils as well as LEGO-based foundation models, and the erosion activity utilised a 3D printer to assist with construction of building models. The activities seek to enhance students' academic achievement, excite them about geotechnical engineering, and motivate them to study science and math. Pre- and post-activity evaluations were conducted to assess both the suitability of the activities and the students' learning. Initial results show that students gain a reasonable understanding of engineering principles. Moreover, the geotechnical engineering activities provided students an opportunity to apply their math skills and science knowledge.

Nanoscale Interactions between Engineered Nanomaterials and Black Carbon (Biochar) in Soil

USDA-ARS?s Scientific Manuscript database

An understanding of the interactions between engineered nanomaterials (NMs) and soil constituents, and a comprehension of how these interactions may affect biological uptake and toxicity are currently lacking. Charcoal black carbon is a normal constituent of soils due to fire history, and can be pre...

Communally Nesting Migratory Birds Create Ecological Hot-Spots in Tropical Australia.

PubMed

Natusch, Daniel J D; Lyons, Jessica A; Brown, Gregory; Shine, Richard

2016-01-01

Large numbers of metallic starlings (Aplonis metallica) migrate annually from New Guinea to the rainforests of tropical Australia, where they nest communally in single emergent trees (up to 1,000 birds). These aggregations create dense and species-rich faunal "hot-spots", attracting a diverse assemblage of local consumers that utilise this seasonal resource. The starlings nested primarily in poison-dart trees (Antiaris toxicaria) near the rainforest-woodland boundary. Surveys underneath these colonies revealed that bird-derived nutrients massively increased densities of soil invertebrates and mammals (primarily wild pigs) beneath trees, year-round. Flying invertebrates, nocturnal birds, reptiles, and amphibians congregated beneath the trees when starlings were nesting (the wet-season). Diurnal birds (primarily cockatoos and bush turkeys) aggregated beneath the trees during the dry-season to utilise residual nutrients when the starlings were not nesting. The abundance of several taxa was considerably higher (to > 1000-fold) under colony trees than under nearby trees. The system strikingly resembles utilisation of bird nesting colonies by predators in other parts of the world but this spectacular system has never been described, emphasizing the continuing need for detailed natural-history studies in tropical Australia.

Communally Nesting Migratory Birds Create Ecological Hot-Spots in Tropical Australia

PubMed Central

Natusch, Daniel J. D.; Lyons, Jessica A.; Brown, Gregory; Shine, Richard

2016-01-01

Large numbers of metallic starlings (Aplonis metallica) migrate annually from New Guinea to the rainforests of tropical Australia, where they nest communally in single emergent trees (up to 1,000 birds). These aggregations create dense and species-rich faunal “hot-spots”, attracting a diverse assemblage of local consumers that utilise this seasonal resource. The starlings nested primarily in poison-dart trees (Antiaris toxicaria) near the rainforest-woodland boundary. Surveys underneath these colonies revealed that bird-derived nutrients massively increased densities of soil invertebrates and mammals (primarily wild pigs) beneath trees, year-round. Flying invertebrates, nocturnal birds, reptiles, and amphibians congregated beneath the trees when starlings were nesting (the wet-season). Diurnal birds (primarily cockatoos and bush turkeys) aggregated beneath the trees during the dry-season to utilise residual nutrients when the starlings were not nesting. The abundance of several taxa was considerably higher (to > 1000-fold) under colony trees than under nearby trees. The system strikingly resembles utilisation of bird nesting colonies by predators in other parts of the world but this spectacular system has never been described, emphasizing the continuing need for detailed natural-history studies in tropical Australia. PMID:27706197

KSC-07pd1340

NASA Image and Video Library

2007-06-04

KENNEDY SPACE CENTER, FLA. -- In the Payload Handling Servicing Facility, an overhead crane lifts the Phoenix spacecraft from its stand for a move to a rotation stand for an interim weight and center of gravity determination. The Phoenix mission is the first project in NASA's first openly competed program of Mars Scout missions. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. It will serve as NASA's first exploration of a potential modern habitat on Mars and open the door to a renewed search for carbon-bearing compounds, Photo credit: NASA/George Shelton

KSC-07pd1341

NASA Image and Video Library

2007-06-04

KENNEDY SPACE CENTER, FLA. -- In the Payload Handling Servicing Facility, an overhead crane lowers the Phoenix spacecraft onto a rotation stand for an interim weight and center of gravity determination. The Phoenix mission is the first project in NASA's first openly competed program of Mars Scout missions. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. It will serve as NASA's first exploration of a potential modern habitat on Mars and open the door to a renewed search for carbon-bearing compounds, Photo credit: NASA/George Shelton

Health assessment for Koppers Company, Inc. , National Priorities List (NPL) Site, Texarkana, Texas, Region 6. CERCLIS No. TXD980623904. Final report

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

Not Available

The Koppers Company, Inc. Site located in Texarkana, Texas is on the National Priorities List. The site is the former location of a wood treatment facility. The site is contaminated with numerous chemicals from the former wood treatment operations including polyaromatic hydrocarbons (PAH), phenolic compounds, polychlorinated dibenzofurans (PCDF). Previous remedial activity has included reseeding and the installation of sod in highly contaminated residential areas. The primary environmental pathways of potential concern are surface soils and ground water. Long-term exposures to contaminated soils in the residential area pose a potential health risk for ingestion and dermal absorption of soil contaminants. Groundmore » water beneath the site is contaminated and would pose a potential health risk if used for potable purposes.« less

KSC-07pd2075

NASA Image and Video Library

2007-07-23

KENNEDY SPACE CENTER, FLA. — Attached to an overhead crane, the Phoenix Mars Lander is lifted up alongside the mobile service tower on Launch Pad 17-A at Cape Canaveral Air Force Station. Once inside the tower, the lander will be mated to the Delta II launch vehicle. Launch of NASA's Phoenix Mars Lander is scheduled for Aug. 3. There are two instantaneous launch times, 5:35:18 and 6:11:24 a.m. EDT. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. NASA/George Shelton

KSC-07pd1338

NASA Image and Video Library

2007-06-04

KENNEDY SPACE CENTER, FLA. -- An overhead crane lifts the Phoenix spacecraft from its stand for a move to a rotation stand for an interim weight and center of gravity determination. The Phoenix mission is the first project in NASA's first openly competed program of Mars Scout missions. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. It will serve as NASA's first exploration of a potential modern habitat on Mars and open the door to a renewed search for carbon-bearing compounds, Photo credit: NASA/George Shelton

KSC-07pd1693

NASA Image and Video Library

2007-06-28

KENNEDY SPACE CENTER, FLA. -- On Launch Pad 17-A at Cape Canaveral Air Force Station, the second stage of the Delta II launch vehicle for NASA's Phoenix Mars Lander is suspended in front of the mobile service tower while workers place protective panels around the nozzle. The second stage will be lifted into the mobile service tower and mated with the Delta's first stage. Phoenix is scheduled to launch Aug. 3. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Kim Shiflett

KSC-07pd2113

NASA Image and Video Library

2007-07-27

KENNEDY SPACE CENTER, FLA. -- On Launch Pad 17-A at Cape Canaveral Air Force Station, the first half of the fairing is moved toward the Phoenix Mars Lander for installation. Phoenix is targeted for launch on Aug. 3 aboard a Delta II rocket. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth nose cone, protecting the spacecraft during launch and ascent. Phoenix will land in icy soils near the north polar, permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. NASA/George Shelton

KSC-07pd1691

NASA Image and Video Library

2007-06-28

KENNEDY SPACE CENTER, FLA. -- The second stage of the Delta II launch vehicle for NASA's Phoenix Mars Lander arrives on Launch Pad 17-A at Cape Canaveral Air Force Station. The second stage will be lifted into the mobile service tower and mated with the Delta's first stage. The second stage will be lifted into the mobile service tower and mated with the first stage. Phoenix is scheduled to launch Aug. 3. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Kim Shiflett

KSC-07pd2116

NASA Image and Video Library

2007-07-27

KENNEDY SPACE CENTER, FLA. -- On Launch Pad 17-A at Cape Canaveral Air Force Station, the second half of the fairing (in the foreground) moves toward the Phoenix Mars Lander for installation. Phoenix is targeted for launch on Aug. 3 aboard a Delta II rocket. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth nose cone, protecting the spacecraft during launch and ascent. Phoenix will land in icy soils near the north polar, permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. NASA/George Shelton

KSC-07pd2115

NASA Image and Video Library

2007-07-27

KENNEDY SPACE CENTER, FLA. -- On Launch Pad 17-A at Cape Canaveral Air Force Station, the first half of the fairing is moved into place around the Phoenix Mars Lander for installation. Phoenix is targeted for launch on Aug. 3 aboard a Delta II rocket. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth nose cone, protecting the spacecraft during launch and ascent. Phoenix will land in icy soils near the north polar, permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. NASA/George Shelton

KSC-07pd1339

NASA Image and Video Library

2007-06-04

KENNEDY SPACE CENTER, FLA. -- In the Payload Handling Servicing Facility, an overhead crane lifts the Phoenix spacecraft from its stand for a move to a rotation stand for an interim weight and center of gravity determination. The Phoenix mission is the first project in NASA's first openly competed program of Mars Scout missions. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. It will serve as NASA's first exploration of a potential modern habitat on Mars and open the door to a renewed search for carbon-bearing compounds, Photo credit: NASA/George Shelton

The United States Army Medical Department Journal, April - June 2008

DTIC Science & Technology

2008-06-01

Amazon community at Iquitos, Stancil42 (Naval Medical Research Center Detachment, Peru ) received a grant to optimize strategies for preventing the breeding...Detachment, Lima, Peru ; Naval Medical Research Unit-2, Jakarta, Indonesia; and the Naval Medical Research Unit 3, Cairo, Egypt. These resources...the soil beneath tents and camps. In an effort to prevent sand flies breeding in rodent burrows, the Genesis Company (Wellington, Colorado) won an

U.S. Army Medical Department Journal, April-June 2008

DTIC Science & Technology

2008-06-01

IGR), against dengue vector mosquitoes. In the Peruvian Amazon community at Iquitos, Stancil42 (Naval Medical Research Center Detachment, Peru ...Research Unit- Kenya, Nairobi; Naval Medical Research Center Detachment, Lima, Peru ; Naval Medical Research Unit-2, Jakarta, Indonesia; and the Naval...These projects have revealed that sand flies often emerge from the soil beneath tents and camps. In an effort to prevent sand flies breeding in rodent

Infiltration performance of engineered surfaces commonly used for distributed stormwater management

NASA Astrophysics Data System (ADS)

Valinski, Nicholas A.

Engineered porous media are commonly used in low impact development (LID) structures to mitigate excess stormwater in urban environments. Differences in infiltrability of these LID systems arise from the wide variety of materials used to create porous surfaces and subsequent maintenance, debris loading, and physical damage. In this study, infiltration capacity of six common materials was tested by multiple replicate experiments with automated mini-disk infiltrometers. The tested materials included porous asphalt, porous concrete, porous brick pavers, flexible porous pavement, engineered soils, and native soils. Porous asphalt, large porous brick pavers, and curb cutout rain gardens showed the greatest infiltration rates. Most engineered porous pavements and soils performed better than the native silt loam soils. Infiltration performance was found to be related more to site design and environmental factors than material choice. Sediment trap zones in both pavements and engineered soil rain gardens were found to be beneficial to the whole site performance. Winter chloride application had a large negative impact on poured in place concrete, making it a poor choice for heavily salted areas.

Infiltration performance of engineered surfaces commonly used for distributed stormwater management.

PubMed

Valinski, N A; Chandler, D G

2015-09-01

Engineered porous media are commonly used in low impact development (LID) structures to mitigate excess stormwater in urban environments. Differences in infiltrability of these LID systems arise from the wide variety of materials used to create porous surfaces and subsequent maintenance, debris loading, and physical damage. In this study, the infiltration capacity of six common materials was tested by multiple replicate experiments with automated mini-disk infiltrometers. The tested materials included porous asphalt, porous concrete, porous brick pavers, flexible porous pavement, engineered soils, and native soils. Porous asphalt, large porous brick pavers, and curb cutout rain gardens showed the greatest infiltration rates. Most engineered porous pavements and soils performed better than the native silt loam soils. Infiltration performance was found to be related more to site design and environmental factors than material choice. Sediment trap zones in both pavements and engineered soil rain gardens were found to be beneficial to the whole site performance. Winter chloride application had a large negative impact on poured in place concrete, making it a poor choice for heavily salted areas. Copyright © 2015 Elsevier Ltd. All rights reserved.

Hanford Site Groundwater Monitoring for Fiscal Year 2000

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

Hartman, Mary J.; Morasch, Launa F.; Webber, William D.

2001-03-01

This report presents the results of groundwater and vadose zone monitoring and remediation for fiscal year 2000 on the U.S. Department of Energy's Hanford Site, Washington. The most extensive contaminant plumes are tritium, iodine-129, and nitrate, which all had multiple sources and are very mobile in groundwater. Carbon tetrachloride and associated organic constituents form a relatively large plume beneath the central part of the Site. Hexavalent chromium is present in smaller plumes beneath the reactor areas along the river and beneath the central part of the site. Strontium-90 exceeds standards beneath each of the reactor areas, and technetium-99 and uraniummore » are present in the 200 Areas. RCRA groundwater monitoring continued during fiscal year 2000. Vadose zone monitoring, characterization, remediation, and several technical demonstrations were conducted in fiscal year 2000. Soil gas monitoring at the 618-11 burial ground provided a preliminary indication of the location of tritium in the vadose zone and in groundwater. Groundwater modeling efforts focused on 1) identifying and characterizing major uncertainties in the current conceptual model and 2) performing a transient inverse calibration of the existing site-wide model. Specific model applications were conducted in support of the Hanford Site carbon tetrachloride Innovative Treatment Remediation Technology; to support the performance assessment of the Immobilized Low-Activity Waste Disposal Facility; and in development of the System Assessment Capability, which is intended to predict cumulative site-wide effects from all significant Hanford Site contaminants.« less

Nurse Plants vs. Nurse Objects: Effects of Woody Plants and Rocky Cavities on the Recruitment of the Pilosocereus leucocephalus Columnar Cactus

PubMed Central

Munguía-Rosas, Miguel Angel; Sosa, Vinicio J.

2008-01-01

Background and Aims Most studies on cactus recruitment have focused on the role of woody plants as seedling facilitators. Although the spatial association of cacti with objects had been described, the mechanisms underlying this association remain unknown. The aims of this study were to identify which mechanisms facilitate the establishment of a columnar cactus under the shade and protection of objects and to compare these mechanisms with those involved in plant–plant facilitation. Methods Three split-split-plot field experiments were conducted to compare the effects of two microhabitats (inside rocky cavities and beneath plant canopies) on seed removal, germination, seedling survivorship and dry weight. Flat, open spaces were used as the control. For each microhabitat, the effect of seed or seedling protection and substrate limitation were explored; aboveground microclimate and some soil properties were also characterized. Key Results The permanence of superficial seeds was greater inside rocky cavities than beneath woody plant canopies or on flat, open areas. Germination was similar in cavities and beneath plant canopies, but significantly higher than on flat, open areas. Seedling survivorship was greater beneath plant canopies than inside cavities or on flat, open spaces. Conclusions The mechanisms of plant facilitation are different from those of object facilitation. There are seed–seedling conflicts involved in the recruitment of P. leucocephalus: nurse plants favour mainly seedling survivorship by providing a suitable microenvironment, while nurse objects mainly favour seed permanence, by protecting them from predators. PMID:18056054

Molecular characterization of dissolved organic matter associated with the Greenland ice sheet

NASA Astrophysics Data System (ADS)

Bhatia, Maya P.; Das, Sarah B.; Longnecker, Krista; Charette, Matthew A.; Kujawinski, Elizabeth B.

2010-07-01

Subsurface microbial oxidation of overridden soils and vegetation beneath glaciers and ice sheets may affect global carbon budgets on glacial-interglacial timescales. The likelihood and magnitude of this process depends on the chemical nature and reactivity of the subglacial organic carbon stores. We examined the composition of carbon pools associated with different regions of the Greenland ice sheet (subglacial, supraglacial, proglacial) in order to elucidate the type of dissolved organic matter (DOM) present in the subglacial discharge over a melt season. Electrospray ionization (ESI) Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry coupled to multivariate statistics permitted unprecedented molecular level characterization of this material and revealed that carbon pools associated with discrete glacial regions are comprised of different compound classes. Specifically, a larger proportion of protein-like compounds were observed in the supraglacial samples and in the early melt season (spring) subglacial discharge. In contrast, the late melt season (summer) subglacial discharge contained a greater fraction of lignin-like and other material presumably derived from underlying vegetation and soil. These results suggest (1) that the majority of supraglacial DOM originates from autochthonous microbial processes on the ice sheet surface, (2) that the subglacial DOM contains allochthonous carbon derived from overridden soils and vegetation as well as autochthonous carbon derived from in situ microbial metabolism, and (3) that the relative contribution of allochthonous and autochthonous material in subglacial discharge varies during the melt season. These conclusions are consistent with the hypothesis that, given sufficient time (e.g., overwinter storage), resident subglacial microbial communities may oxidize terrestrial material beneath the Greenland ice sheet.

75 FR 48726 - Notice of Lodging of Consent Decree Under the Resource Conservation and Recovery Act

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-11

... single production facility in Plant City, Florida that has been in operation at the current approximate 3... settlement, CFI has re-engineered its plant to cease generating hazardous wastewater previously commingled... reduction program; install synthetic protective barriers beneath its production plants; provide $163.5...

Mining Hidden Gems Beneath the Surface: A Look At the Invisible Web.

ERIC Educational Resources Information Center

Carlson, Randal D.; Repman, Judi

2002-01-01

Describes resources for researchers called the Invisible Web that are hidden from the usual search engines and other tools and contrasts them with those resources available on the surface Web. Identifies specialized search tools, databases, and strategies that can be used to locate credible in-depth information. (Author/LRW)

Martian (and Cold Region Lunar) Soil Mechanics Considerations

NASA Astrophysics Data System (ADS)

Chua, Koon Meng; Johnson, Stewart W.

1998-01-01

The exploration of Mars has generated a lot of interest in recent years. With the completion of the Pathfinder Mission and the commencement of detailed mapping by Mars Global Surveyor, the possibility of an inhabited outpost on the planet is becoming more realistic. In spite of the upbeat mood, human exploration of Mars is still many years in the future. Additionally, the earliest return of any martian soil samples will probably not be until 2008. So why the discussion about martian soil mechanics when there are no returned soil samples on hand to examine? In view of the lack of samples, the basis of this or any discussion at this time must necessarily be one that involves conjecture, but not without the advantage of our knowledge of regolith mechanics of the Moon and soil mechanics on Earth. The objective of this presentation/discussion is fourfold: (1) Review some basic engineering-related information about Mars that may be of interest to engineers, and scientists - including characteristics of water and C02 at low temperature; (2) review and bring together principles of soil mechanics pertinent to studying and predicting how martian soil may behave, including the morphology and physical characteristics of coarse-grained and fine-grained soils (including clays), the characteristics of collapsing soils, potentials and factors that affect migration of water in unfrozen and freezing/frozen soils, and the strength and stiffness characteristics of soils at cold temperatures; (3) discuss some preliminary results of engineering experiments performed with frozen lunar soil simulants, JSC-1, in the laboratory that show the response to temperature change with and without water, effects of water on the strength and stiffness at ambient and at below freezing temperatures; and (4) discuss engineering studies that could be performed prior to human exploration and engineering research to be performed alongside future scientific missions to that planet.

Revised Rapid Soils Analysis Kit (RSAK) - Wet Methodology

DTIC Science & Technology

2018-01-01

respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other...Airfields and Pavements Branch (GMA) of the Engineering Systems and Materials Division (GM), U.S. Army Engineer Research and Development Center...the soil type and the in-place soil conditions. This research project was designed to provide soldiers who have minimal to no experience in soil

Incorporating the site variability and laboratory/in-situ testing variability of soil properties in geotechnical engineering design : research project capsule : technology transfer program.

DOT National Transportation Integrated Search

2016-04-01

While structural engineering deals with mostly homogeneous manmade materials : (e.g., concrete and steel), geotechnical engineering typically involves highly varied : natural materials (e.g., soil and rock). As a result, high variance of the resistan...

Modification of hydraulic conductivity in granular soils using waste materials.

PubMed

Akbulut, S; Saglamer, A

2004-01-01

This paper evaluates the use of waste products such as silica fume and fly ash in modification of the granular soils in order to remove some environmental problems and create new useful findings in the field of engineering. It is known that silica fume and fly ash, as well as clay material, are used in geotechnical engineering because of their pozzolanic reactivity and fineness to improve the soil properties needed with respect to engineering purposes. The main objective of this research project was to investigate the use of these materials in geotechnical engineering and to improve the hydraulic properties of soils by means of grouting. For this reason, firstly, suitable grouts in suspension forms were prepared by using silica fume, fly ash, clay and cement in different percentages. The properties of these cement-based grouts were then determined to obtain the desired optimum values for grouting. After that, these grouts were penetrated into the soil samples under pressure. The experimental work indicates that these waste materials and clay improved the physical properties and the fluidity of the cement-based grouts and they also decreased the hydraulic conductivity of the grouted soil samples by sealing the voids of the soil. The results of this study have important findings concerning the use of these materials in soil treatment and the improvement of hydraulic conductivity of the soils.

Military Curriculum Materials for Vocational and Technical Education. Soils Engineering 3-1. Edition 1.

ERIC Educational Resources Information Center

Ohio State Univ., Columbus. National Center for Research in Vocational Education.

This individualized, self-paced course for independent study in soils engineering was adapted from military curriculum materials for use in vocational education. The course is designed to acquaint students with various soil types and their characteristics using various procedures, tests, and recording forms. Some of these duties are determining…

ELF Communications System Ecological Monitoring Program: Electromagnetic Field Measurements and Engineering Support-1991

DTIC Science & Technology

1992-12-01

engineering support for completed studies--namely, the wetlands, slime mold , and bird species and communities studies performed in Wisconsin-appears in previous...3 4. ENGINEERING SUPPORT ACTIVITIES 4.1 Soil Amoeba Growth Chambers 4.1.1 Background 3 The soil amoeba and now-completed slime mold studies both...cultures of soil amoeba and slime mold to the earth’s ambient temperature. It is also desirable to expose the cultures to the same EM environment that they

Temporal variability of soil water repellency in field conditions under humid Mediterranean climate (South of Spain)

NASA Astrophysics Data System (ADS)

Martinez-Murillo, Juan F.; Gabarron-Galeote, Miguel A.; Ruiz-Sinoga, Jose D.

2013-04-01

Soil water repellency (SWR) has become an important field of scientific study because of its effects on soil hydrological behavior, including reduced matrix infiltration, development of fingered flow in structural or textural preferential flow paths, irregular wetting fronts, and increased runoff generation and soil erosion. The aim of this study is to evaluate the temporal variability of SWR in Mediterranean rangeland under humid Mediterranean climatic conditions (Tª=14.5 °C; P=1,010 mm y-1) in South of Spain. Every month from September 2008 to May 2009 (rainy season), soil moisture and SWR was measured in field conditions by means of gravimetric method and Water Drop Penetration Test, respectively. The entire tests were performed in differente eco-geomorphological conditions in the experimental site: North and South aspect hillslopes and beneath shrub and bare soil in every of them. The results indicate that: i) climatic conditions seem to be more transcendent than the vegetal cover for explaining the temporal variability of SWR in field conditions; ii) thus, SWR appears to be controlled by the antecedent rainfall and soil moisture; iii) more severity SWR were observed in patches characterized by sandier soils and/or greater organic matter contents; and iv) the factor 'hillslope aspect' was not found very influential in the degree of SWR.

Genetic by environment interactions affect plant–soil linkages

PubMed Central

Pregitzer, Clara C; Bailey, Joseph K; Schweitzer, Jennifer A

2013-01-01

The role of plant intraspecific variation in plant–soil linkages is poorly understood, especially in the context of natural environmental variation, but has important implications in evolutionary ecology. We utilized three 18- to 21-year-old common gardens across an elevational gradient, planted with replicates of five Populus angustifolia genotypes each, to address the hypothesis that tree genotype (G), environment (E), and G × E interactions would affect soil carbon and nitrogen dynamics beneath individual trees. We found that soil nitrogen and carbon varied by over 50% and 62%, respectively, across all common garden environments. We found that plant leaf litter (but not root) traits vary by genotype and environment while soil nutrient pools demonstrated genotype, environment, and sometimes G × E interactions, while process rates (net N mineralization and net nitrification) demonstrated G × E interactions. Plasticity in tree growth and litter chemistry was significantly related to the variation in soil nutrient pools and processes across environments, reflecting tight plant–soil linkages. These data overall suggest that plant genetic variation can have differential affects on carbon storage and nitrogen cycling, with implications for understanding the role of genetic variation in plant–soil feedback as well as management plans for conservation and restoration of forest habitats with a changing climate. PMID:23919173

Do shrubs reduce the adverse effects of grazing on soil properties?

USGS Publications Warehouse

Eldridge, David J.; Beecham, Genevieve; Grace, James B.

2015-01-01

Increases in the density of woody plants are a global phenomenon in drylands, and large aggregations of shrubs, in particular, are regarded as being indicative of dysfunctional ecosystems. There is increasing evidence that overgrazing by livestock reduces ecosystem functions in shrublands, but that shrubs may buffer the negative effects of increasing grazing. We examined changes in water infiltration and nutrient concentrations in soils under shrubs and in their interspaces in shrublands in eastern Australia that varied in the intensity of livestock grazing. We used structural equation modelling to test whether shrubs might reduce the negative effects of overgrazing on infiltration and soil carbon and nitrogen (henceforth ‘soil nutrients’). Soils under shrubs and subject to low levels of grazing were more stable and had greater levels of soil nutrients. Shrubs had a direct positive effect on soil nutrients; but, grazing negatively affected nutrients by increasing soil bulk density. Structural equation modelling showed that shrubs had a direct positive effect on water flow under ponded conditions but also enhanced water flow, indirectly, through increased litter cover. Any positive effects of shrubs on water flow under low levels of grazing waned at high levels of grazing. Our results indicate that shrubs may reduce the adverse effects of grazing on soil properties. Specifically, shrubs could restrict access to livestock and therefore protect soils and plants beneath their canopies. Low levels of grazing are likely to ensure the retention of soil water and soil carbon and nitrogen in shrubland soils.

'Mister Badger' Pushing Mars Rock

NASA Technical Reports Server (NTRS)

1976-01-01

Viking's soil sampler collector arm successfully pushed a rock on the surface of Mars during the afternoon of Friday, October 8. The irregular-shaped rock was pushed several inches by the Lander's collector arm, which displaced the rock to the left of its original position, leaving it cocked slightly upward. Photographs and other information verified the successful rock push. Photo at left shows the soil sampler's collector head pushing against the rock, named 'Mister Badger' by flight controllers. Photo at right shows the displaced rock and the depression whence it came. Part of the soil displacement was caused by the collector s backhoe. A soil sample will be taken from the site Monday night, October 11. It will then be delivered to Viking s organic chemistry instrument for a series of analyses during the next few weeks. The sample is being sought from beneath a rock because scientists believe that, if there are life forms on Mars, they may seek rocks as shelter from the Sun s intense ultraviolet radiation.

[Rainfall and soil moisture redistribution induced by xerophytic shrubs in an arid desert ecosystem].

PubMed

Wang, Zheng Ning; Wang, Xin Ping; Liu, Bo

2016-03-01

Rainfall partitioning by desert shrub canopy modifies the redistribution of incident rainfall under the canopy, and may affect the distribution pattern of soil moisture around the plant. This study examined the distribution of rainfall and the response of soil moisture beneath the canopy of two dominant desert shrubs, Caragana korshinskii and Artemisia ordosica, in the revegetation area at the southeastern edge of the Tengger Desert. The results showed that throughfall and stemflow ave-ragely occupied 74.4%, 11.3% and 61.8%, 5.5% of the gross precipitation for C. korshinskii and A. ordosica, respectively. The mean coefficients of variation (CV) of throughfall were 0.25 and 0.30, respectively. C. korshinski were more efficient than A. ordosica on stemflow generation. The depth of soil wetting front around the stem area was greater than other areas under shrub canopy for C. korshinski, and it was only significantly greater under bigger rain events for A. ordosica. The shrub canopy could cause the unevenness of soil wetting front under the canopy in consequence of rainfall redistribution induced by xerophytic shrub.

Movement of Endotoxin Through Soil Columns

PubMed Central

Goyal, Sagar M.; Gerba, Charles P.; Lance, J. Clarence

1980-01-01

Land treatment of wastewater is an attractive alternative to conventional sewage treatment systems and is gaining widespread acceptance. Although land application systems prevent surface water pollution and augment the available water supplies, the potential dangers to human health should be evaluated. Since sewage may contain high amounts of bacterial endotoxin, the removal of endotoxin from sewage by percolation through soil was investigated. It was found that 90 to 99% of the endotoxin was removed after travel of sewage through 100 to 250 cm of loamy sand soil. When distilled water was allowed to infiltrate into the soil to simulate rainfall, the endotoxin was mobilized and moved in a concentrated band through the soil column. On testing samples from actual land treatment sites, as much as 480 ng of endotoxin per milliliter was found in some groundwater samples. The presence of endotoxin in potable water is known to be a potential problem under some circumstances, but the importance of endotoxin in water supplies has not been fully assessed. Therefore, the design, operation, and management of land application systems should take into account the fate of endotoxin in groundwater beneath the sites. PMID:7387154

Streptomycin Application Has No Detectable Effect on Bacterial Community Structure in Apple Orchard Soil

PubMed Central

Shade, Ashley; Klimowicz, Amy K.; Spear, Russell N.; Linske, Matthew; Donato, Justin J.; Hogan, Clifford S.; McManus, Patricia S.

2013-01-01

Streptomycin is commonly used to control fire blight disease on apple trees. Although the practice has incited controversy, little is known about its nontarget effects in the environment. We investigated the impact of aerial application of streptomycin on nontarget bacterial communities in soil beneath streptomycin-treated and untreated trees in a commercial apple orchard. Soil samples were collected in two consecutive years at 4 or 10 days before spraying streptomycin and 8 or 9 days after the final spray. Three sources of microbial DNA were profiled using tag-pyrosequencing of 16S rRNA genes: uncultured bacteria from the soil (culture independent) and bacteria cultured on unamended or streptomycin-amended (15 μg/ml) media. Multivariate tests for differences in community structure, Shannon diversity, and Pielou's evenness test results showed no evidence of community response to streptomycin. The results indicate that use of streptomycin for disease management has minimal, if any, immediate effect on apple orchard soil bacterial communities. This study contributes to the profile of an agroecosystem in which antibiotic use for disease prevention appears to have minimal consequences for nontarget bacteria. PMID:23974143

Investigating Seed Longevity of Big Sagebrush (Artemisia tridentata)

USGS Publications Warehouse

Wijayratne, Upekala C.; Pyke, David A.

2009-01-01

The Intermountain West is dominated by big sagebrush communities (Artemisia tridentata subspecies) that provide habitat and forage for wildlife, prevent erosion, and are economically important to recreation and livestock industries. The two most prominent subspecies of big sagebrush in this region are Wyoming big sagebrush (A. t. ssp. wyomingensis) and mountain big sagebrush (A. t. ssp. vaseyana). Increased understanding of seed bank dynamics will assist with sustainable management and persistence of sagebrush communities. For example, mountain big sagebrush may be subjected to shorter fire return intervals and prescribed fire is a tool used often to rejuvenate stands and reduce tree (Juniperus sp. or Pinus sp.) encroachment into these communities. A persistent seed bank for mountain big sagebrush would be advantageous under these circumstances. Laboratory germination trials indicate that seed dormancy in big sagebrush may be habitat-specific, with collections from colder sites being more dormant. Our objective was to investigate seed longevity of both subspecies by evaluating viability of seeds in the field with a seed retrieval experiment and sampling for seeds in situ. We chose six study sites for each subspecies. These sites were dispersed across eastern Oregon, southern Idaho, northwestern Utah, and eastern Nevada. Ninety-six polyester mesh bags, each containing 100 seeds of a subspecies, were placed at each site during November 2006. Seed bags were placed in three locations: (1) at the soil surface above litter, (2) on the soil surface beneath litter, and (3) 3 cm below the soil surface to determine whether dormancy is affected by continued darkness or environmental conditions. Subsets of seeds were examined in April and November in both 2007 and 2008 to determine seed viability dynamics. Seed bank samples were taken at each site, separated into litter and soil fractions, and assessed for number of germinable seeds in a greenhouse. Community composition data from each site, as well as several environmental variables, were used to evaluate seed viability within the context of habitat variation. Initial viability of seeds used in the seed retrieval experiment was 81 and 92 percent for mountain and Wyoming big sagebrush, respectively. After remaining in the field for 24 months, buried Wyoming big sagebrush seeds retained 28-58 percent viability,11-23 percent of seeds under litter remained viable, and no seeds remained viable on the surface (estimates are 95-percent confidence intervals). The odds of remaining viable did not change from 12 to 24 months. However, after 24 months the odds of seeds beneath litter being viable decreased to 75 percent of the odds of viability at 12 months. Similar to Wyoming big sagebrush, buried seeds of mountain big sagebrush were 31-68 percent viable, seeds under litter retained 10-22 percent of their viability, and no surface seeds were viable after 24 months. Both subspecies of big sagebrush had some portion of seed that remained viable for more than one growing season provided they were buried or under litter. Although seeds beneath litter may remain viable in intact communities, seeds are susceptible to incineration during fires. Nine months after seed dispersal, seed bank estimates for Wyoming big sagebrush ranged from 19 to 49 viable seeds/m2 in litter samples and 19-57 viable seeds/m2 in soil samples (95-percent confidence interval). For mountain big sagebrush, estimates were 27-75 viable seeds/m2 in litter samples and 54-139 viable seeds/m2 in soil (95-percent confidence interval). The number of viable seeds present in the seed bank 9 months after seed dispersal was not significantly different from the number present immediately after seed dispersal. Seed viability was highest in mountain big sagebrush sites for seeds on the surface and beneath litter, but decreased after one season. Buried seeds of both subspecies were in equal abundances and may be insulated from the effect

U.s. Geological survey core drilling on the atlantic shelf.

PubMed

Hathaway, J C; Poag, C W; Valentine, P C; Manheim, F T; Kohout, F A; Bothner, M H; Miller, R E; Schultz, D M; Sangrey, D A

1979-11-02

The first broad program of scientific shallow drilling on the U.S. Atlantic continental shelf has delineated rocks of Pleistocene to Late Cretaceous age, including phosphoritic Miocene strata, widespread Eocene carbonate deposits that serve as reflective seismic markers, and several regional unconformities. Two sites, off Maryland and New Jersey, showed light hydrocarbon gases having affinity to mature petroleum. Pore fluid studies showed that relatively fresh to brackish water occurs beneath much of the Atlantic continental shelf, whereas increases in salinity off Georgla and beneath the Florida-Hatteras slope suggest buried evaporitic strata. The sediment cores showed engineering properties that range from good foundation strength to a potential for severe loss of strength through interaction between sediments and man-made structures.

The status of soil mapping for the Idaho National Engineering Laboratory

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

Olson, G.L.; Lee, R.D.; Jeppesen, D.J.

This report discusses the production of a revised version of the general soil map of the 2304-km{sup 2} (890-mi{sup 2}) Idaho National Engineering Laboratory (INEL) site in southeastern Idaho and the production of a geographic information system (GIS) soil map and supporting database. The revised general soil map replaces an INEL soil map produced in 1978 and incorporates the most current information on INEL soils. The general soil map delineates large soil associations based on National Resources Conservation Services [formerly the Soil Conservation Service (SCS)] principles of soil mapping. The GIS map incorporates detailed information that could not be presentedmore » on the general soil map and is linked to a database that contains the soil map unit descriptions, surficial geology codes, and other pertinent information.« less

An Underground Revolution: Biodiversity and Soil Ecological Engineering for Agricultural Sustainability.

PubMed

Bender, S Franz; Wagg, Cameron; van der Heijden, Marcel G A

2016-06-01

Soil organisms are an integral component of ecosystems, but their activities receive little recognition in agricultural management strategies. Here we synthesize the potential of soil organisms to enhance ecosystem service delivery and demonstrate that soil biodiversity promotes multiple ecosystem functions simultaneously (i.e., ecosystem multifunctionality). We apply the concept of ecological intensification to soils and we develop strategies for targeted exploitation of soil biological traits. We compile promising approaches to enhance agricultural sustainability through the promotion of soil biodiversity and targeted management of soil community composition. We present soil ecological engineering as a concept to generate human land-use systems, which can serve immediate human needs while minimizing environmental impacts. Copyright © 2016 Elsevier Ltd. All rights reserved.

Welcome to Pacific Earthquake Engineering Research Center - PEER

Science.gov Websites

Triggering and Effects at Silty Soil Sites" - PEER Research Project Highlight: "Dissipative Base ; Upcoming Events More June 10-13, 2018 Geotechnical Earthquake Engineering and Soil Dynamics V 2018 - Call

Detection of explosives in soils

DOEpatents

Chambers, William B.; Rodacy, Philip J.; Phelan, James M.; Woodfin, Ronald L.

2002-01-01

An apparatus and method for detecting explosive-indicating compounds in subsurface soil. The apparatus has a probe with an adsorbent material on some portion of its surface that can be placed into soil beneath the ground surface, where the adsorbent material can adsorb at least one explosive-indicating compound. The apparatus additional has the capability to desorb the explosive-indicating compound through heating or solvent extraction. A diagnostic instrument attached to the probe detects the desorbed explosive-indicating compound. In the method for detecting explosive-indicating compounds in soil, the sampling probe with an adsorbent material on at least some portion of a surface of the sampling probe is inserted into the soil to contact the adsorbent material with the soil. The explosive-indicating compounds are then desorbed and transferred as either a liquid or gas sample to a diagnostic tool for analysis. The resulting gas or liquid sample is analyzed using at least one diagnostic tool selected from the group consisting of an ion-mobility spectrometer, a gas chromatograph, a high performance liquid chromatograph, a capillary electrophoresis chromatograph, a mass spectrometer, a Fourier-transform infrared spectrometer and a Raman spectrometer to detect the presence of explosive-indicating compounds.

Persisting effects of armored military maneuvers on some soils of the Mojave Desert

USGS Publications Warehouse

Prose, D.V.

1985-01-01

Soil compaction and substrate modification produced during large-scale armored military maneuvers in the early 1940s were examined in 1981 at seven sites in California's eastern Mojave Desert Recording penetrometer measurements show that tracks left by a single pass of an M3 "medium" tank have average soil resistance values that are 50% greater than those of the surrounding untracked soil in the upper 20 cm At one site, measurements made along short segments of track that have been visually eliminated by erosion and deposition processes show a 73% increase in penetrometer resistance over adjacent, undisturbed soils Dirt roadways at three former base camp locations could not be penetrated below 5-10 cm because of extreme compaction Soil bulk density was not as sensitive an indicator of soil compaction as was penetrometer resistance Density values in the upper 10 cm of soil are not significantly different between tank tracks and undisturbed soils at most sites, and roadways at two base camps show an average increase in bulk density of only 12% over adjacent soils. Trench excavations across tank tracks show that physical modifications of the substrate can extend vertically beneath a track to a depth of 25 cm and outward from a track's edge to 50 cm These soil disturbances are probably major factors that encourage accelerated soil erosion throughout the manuever area and also retard or prevent the return of vegetation to pre-disturbance conditions ?? 1985 Springer-Verlag New York Inc.

To manage or not to manage: The role of silviculture in sequestering carbon in the specter of climate change

Treesearch

Jianwei Zhang; Robert F. Powers; Carl N. Skinner

2010-01-01

Forests and the soils beneath them are a major sink for atmospheric CO2 and play a significant role in offsetting CO2 emissions by converting CO2 into wood through photosynthesis and storing it for an extended period. However, forest fires counter carbon sequestration because pyrolysis converts organic C to CO and CO2, releasing decades or centuries of bound C to the...

Programmatic Environmental Assessment for Standard Targetry Replacement

DTIC Science & Technology

2006-04-01

Appalachian oak and pine-oak stands. Pine barrens with grassy savannas are found in dry sandy soils, with thick shrubs often growing beneath the... fir . In interior valleys, the coniferous forest is less dense than along the coast; and often contains deciduous trees, such as big-leaf maple...Oregon ash, and black cottonwood. There are prairies that support open stands of oaks, or are broken by groves of Douglas fir and other trees

Range Condition Assessment Report for Naval Surface Warfare Center, Dahlgren Laboratory Ranges, Dahlgren, Virginia

DTIC Science & Technology

2010-09-01

following alternative: vegetative soil cap, offsite disposal of sediments, and phytoremediation to control groundwater levels beneath the landfill. The...cap. These issues include poor condition of the phytoremediation trees on the surface of the landfill cap and blockage of the pond outfall structure...to be completed in January 2009. Based on the poor condition of the phytoremediation trees on the landfill cap, a supplemental tree planting

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.

Proposed Demolition of Hangars; Projects 11-0098-11-0102 Environmental Assessment

DTIC Science & Technology

2012-03-22

decrease its space and energy use • Be compliant with current land use zoning ( Industrial ) • Not violate any provisions of the National Historic... industrial usage of the hangars, contamination of shallow soil is known to exist beneath or adjacent to the structures undergoing demolition and...buildings occur in an industrial part of the base which has already been heavily disturbed due to past construction activities. The buildings proposed for

KSC-07pd2163

NASA Image and Video Library

2007-08-03

KENNEDY SPACE CENTER, FLA. -- Preparations to move the mobile service tower, or gantry, from around the Delta II 7925 rocket are under way under the lights on Launch Pad 17A at Cape Canaveral Air Force Station. Equipped with three stages and nine strap-on solid rocket motors, the Delta II rocket packs plenty of punch for sending the Phoenix spacecraft on its way toward Mars. Launch is targeted for Aug. 4 during one of two opportunities for liftoff: 5:26 or 6:02 a.m. EDT. Phoenix will land in icy soils near the north polar, permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Jim Grossmann

KSC-07pd2167

NASA Image and Video Library

2007-08-03

KENNEDY SPACE CENTER, FLA. -- The solid rocket boosters on the Delta II 7925 rocket are revealed following the retraction of the mobile service tower, or gantry, on Launch Pad 17A at Cape Canaveral Air Force Station. Equipped with three stages and nine strap-on solid rocket motors, the Delta II rocket packs plenty of punch for sending the Phoenix spacecraft on its way toward Mars. Launch is targeted for Aug. 4 during one of two opportunities for liftoff: 5:26 or 6:02 a.m. EDT. Phoenix will land in icy soils near the north polar, permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Jim Grossmann

KSC-07pd1337

NASA Image and Video Library

2007-06-04

KENNEDY SPACE CENTER, FLA. -- Workers in the Payload Handling Servicing Facility attach an overhead crane to the Phoenix spacecraft. The spacecraft will be lifted and moved to a rotation stand for an interim weight and center of gravity determination. The Phoenix mission is the first project in NASA's first openly competed program of Mars Scout missions. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. It will serve as NASA's first exploration of a potential modern habitat on Mars and open the door to a renewed search for carbon-bearing compounds, Photo credit: NASA/George Shelton

KSC-07pd2165

NASA Image and Video Library

2007-08-03

KENNEDY SPACE CENTER, FLA. -- The Delta II 7925 rocket is revealed as the mobile service tower, or gantry, rolls back on Launch Pad 17A at Cape Canaveral Air Force Station. Equipped with three stages and nine strap-on solid rocket motors, the Delta II rocket packs plenty of punch for sending the Phoenix spacecraft on its way toward Mars. Launch is targeted for Aug. 4 during one of two opportunities for liftoff: 5:26 or 6:02 a.m. EDT. Phoenix will land in icy soils near the north polar, permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Jim Grossmann

KSC-07pd2168

NASA Image and Video Library

2007-08-03

KENNEDY SPACE CENTER, FLA. -- Rollback of the mobile service tower, or gantry, from around the Delta II 7925 rocket is complete on Launch Pad 17A at Cape Canaveral Air Force Station. Equipped with three stages and nine strap-on solid rocket motors, the Delta II rocket packs plenty of punch for sending the Phoenix spacecraft on its way toward Mars. Launch is targeted for Aug. 4 during one of two opportunities for liftoff: 5:26 or 6:02 a.m. EDT. Phoenix will land in icy soils near the north polar, permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. Photo credit: NASA/Jim Grossmann

KSC-07pd2117

NASA Image and Video Library

2007-07-27

KENNEDY SPACE CENTER, FLA. -- On Launch Pad 17-A at Cape Canaveral Air Force Station, the second half of the fairing (in the foreground) moves closer to the Phoenix Mars Lander for installation toward the first half. Phoenix is targeted for launch on Aug. 3 aboard a Delta II rocket. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth nose cone, protecting the spacecraft during launch and ascent. Phoenix will land in icy soils near the north polar, permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing on Mars is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. NASA/George Shelton

The sign, magnitude and potential drivers of change in surface water extent in Canadian tundra

NASA Astrophysics Data System (ADS)

Carroll, Mark L.; Loboda, Tatiana V.

2018-04-01

The accelerated rate of warming in the Arctic has considerable implications for all components of ecosystem functioning in the High Northern Latitudes. Changes to hydrological cycle in the Arctic are particularly complex as the observed and projected warming directly impacts permafrost and leads to variable responses in surface water extent which is currently poorly characterized at the regional scale. In this study we take advantage of the 30 plus years of medium resolution (30 m) Landsat data to quantify the spatial patterns of change in the extent of water bodies in the Arctic tundra in Nunavut, Canada. Our results show a divergent pattern of change—growing surface water extent in the north-west and shrinking in the south-east—which is not a function of the overall distribution of surface water in the region. The observed changes cannot be explained by latitudinal stratification, nor is it explained by available temperature and precipitation records. However, the sign of change appears to be consistent within the boundaries of individual watersheds defined by the Canada National Hydro Network based on the random forest analysis. Using land cover maps as a proxy for ecological function we were able to link shrinking tundra water bodies to substrates with shallow soil layers (i.e. bedrock and barren landscapes) with a moderate correlation (R 2 = 0.46, p < 0.001). It has previously been reported that rising temperatures are driving a deepening of the active layer and shrinking water bodies can be associated with coarse textured soils beneath the lakes. Unlike water bodies with soil, or gravel, beneath them the water bodies that are situated on bedrock are likely cut off from ground water. Drying water bodies clustered in areas of bedrock and thin soils points to evaporation as an important driver of surface water decrease in these cases.

Methane and CO2 fluxes from peat soil, palm stems and field drains in two oil palm plantations in Sarawak, Borneo, on different tropical peat soil types.

NASA Astrophysics Data System (ADS)

Manning, Frances; Lip Khoon, Kho; Hill, Tim; Arn Teh, Yit

2017-04-01

Oil palm plantations have been expanding rapidly on tropical peat soils in the last 20 years, with 50 % of SE Asian peatlands now managed as industrial or small-holder plantations, up from 11% in 1990. Tropical peat soils are an important carbon (C) store, containing an estimated 17 % of total peatland C. There are large uncertainties as to the soil C dynamics in oil palm plantations on peat due to a shortage of available data. It is therefore essential to understand the soil C cycle in order to promote effective management strategies that optimise yields, whilst maintaining the high C storage capacity of the soil. Here we present CO2 and CH4 fluxes from two oil palm plantations in Sarawak, Malaysia on peat soils. Data were collected from different surface microforms within each plantation that experienced different surface management practices. These included the area next to the palm, in bare soil harvest paths, beneath frond piles, underneath cover crops, from the surface of drains, and from palm stems. Data were collected continuously over one year and analysed with different environmental variables, including soil temperature, WTD, O2, soil moisture and weather data in order to best determine the constraints on the dataset. Total soil respiration (Rtot) varied between 0.09 and 1.59 g C m-2 hr-1. The largest fluxes (0.59 - 1.59 g C m-2 hr-1) were measured next to the palms. Larger CO2 fluxes were observed beneath the cover crops than in the bare soil. This trend was attributed to priming effects from the input of fresh plant litter and exudates. Peat soil type was shown to have significantly different fluxes. The different plantations also had different environmental drivers best explaining the variation in Rtot - with soil moisture being the most significant variable on Sabaju series soil and soil temperature being the most significant environmental variable in the plantation with the Teraja series soil. Rtot was shown to reduce significantly with increasing distance from the palm. The relationship between Rtot and root biomass, which also decreased significantly with increasing distance from the palm, allowed for the partitioning of Rtot into peat oxidation and Ra. Here rates of peat oxidation were estimated to be 0.11 g C m-2 hr-1 following partitioning, and 0.16 g C m-2 hr-1 without partitioning. Methane fluxes varied between 0 and 1.95 g C m-2 hr-1. The largest methane fluxes were emitted from collection drains. Methane oxidation was occasionally observed in field drains, when the water table dropped below the depth of the drain. Soil methane fluxes were lower than those from collection drains. The highest methane fluxes were observed next to palms (0.02 mg C m-2 hr-1) and the lowest under frond piles (0.08 mg C m-2 hr-1). Methane emissions were measured from the palm stems. Preliminary data gives a range between 0.005 and 0.27 µg C m-2 hr-1. These results show wide ranges in both CO2 and CH4 emissions from different sources within the plantations, with the collection drains being the largest source of C fluxes.

Carbon Dioxide Emissions From Kill Zones Around the Resurgent Dome, Long Valley Caldera, CA

NASA Astrophysics Data System (ADS)

Bergfeld, D.; Evans, W. C.; Farrar, C. D.; Howle, J. F.

2004-12-01

An episode of seismic unrest beneath the resurgent dome at Long Valley caldera (LVC) in eastern California began in 1980 and is associated with approximately 80 cm of cumulative uplift on parts of the dome since that time. Studies of hydrologic and geochemical parameters can be useful in determining the source of uplift; and of particular relevance here, studies of diffuse soil degassing and temperature have been used to examine relations between gas emissions, uplift, and energy release. We present results from an eighteen-month investigation of soil temperature, soil-gas chemistry and CO2 efflux from fourteen discrete areas of vegetation kill that have appeared inside the caldera over the past two decades. Compared with the tree-kill around Mammoth Mountain on the southwest rim of the caldera, dead zones we studied around the resurgent dome are small. Individually the areas cover between 800 and 36,000 m2. All of the areas have some sites with elevated CO2 flux and elevated soil temperature. \\delta 13C values of CO2 from sites in eight of the studied areas are between -5.7 and -3.9\\permil, and are within the range of magmatic CO2. Results from the flux measurements indicate that on average total CO2 emissions from four of the areas sum about 10 tonnes per day. The other vegetation kill areas currently have only a few sites that exhibit anomalous soil temperatures and CO2 flux, and CO2 emissions from these areas are typically less than 0.3 of a tonne per day. The chemical composition of gas emissions from thermal ground in kill zones located 1.5 to 2 km northwest of the Casa Diablo geothermal power plant demonstrate a connection between some of the dead areas and perturbations related to geothermal fluid production. These results and estimates of thermal output from two of the high flux grids are used to evaluate the premise that the gaseous and thermal anomalies are related to magmatic intrusion beneath the resurgent dome.

Conceptional Considerations to Energy Balance and Global Warming Potential of Soil Bioengineering Structures

NASA Astrophysics Data System (ADS)

von der Thannen, Magdalena; Paratscha, Roman; Smutny, Roman; Lampalzer, Thomas; Strauss, Alfred; Rauch, Hans Peter

2016-04-01

Nowadays there is a high demand on engineering solutions considering not only technical aspects but also ecological and aesthetic values. In this context soil bioengineering techniques are often used as standalone solutions or in combination with conventional engineering structures. It is a construction technique that uses biological components for hydraulic and civil engineering solutions. In general it pursues the same objectives as conventional civil engineering structures. Currently the used assessment methods for soil bioengineering structures are referencing technically, ecologically and socio-economically. In a modern engineering approach additionally, environmental impacts and potential added values should be considered. The research project E-Protect aims at developing Environmental Life Cycle Assessment (LCA) models for this special field of alpine protective constructions. Both, the Cumulative Energy Demand (CED) and the Global Warming Potential (GWP) should be considered in an Environmental LCA over the whole life cycle of an engineering structure. The life cycle itself can be divided into three phases: the construction phase, the use phase and the end of life phase. The paper represents a concept to apply an Environmental LCA model for soil bioengineering structures. Beside the construction phase of these structures particular attention will be given to the use phase. It is not only important in terms of engineering effects but also plays an important role for positive carbon footprint due to the growing plants of soil bioengineering structures in contrast to conventional structures. Innovative Environmental LCA models will be applied to soil bioengineering structures which provide a new transparency for the responsible planners and stakeholders, by pointing out the total consumption of resources in all construction phases and components.

Combined Resistivity and Shear Wave Velocity Soil-type Estimation Beneath a Coastal Protection Levee.

NASA Astrophysics Data System (ADS)

Lorenzo, J. M.; Goff, D.; Hayashi, K.

2015-12-01

Unconsolidated Holocene deltaic sediments comprise levee foundation soils in New Orleans, USA. Whereas geotechnical tests at point locations are indispensable for evaluating soil stability, the highly variable sedimentary facies of the Mississippi delta create difficulties to predict soil conditions between test locations. Combined electrical resistivity and seismic shear wave studies, calibrated to geotechnical data, may provide an efficient methodology to predict soil types between geotechnical sites at shallow depths (0- 10 m). The London Avenue Canal levee flank of New Orleans, which failed in the aftermath of Hurricane Katrina, 2005, presents a suitable site in which to pioneer these geophysical relationships. Preliminary cross-plots show electrically resistive, high-shear-wave velocity areas interpreted as low-permeability, resistive silt. In brackish coastal environments, low-resistivity and low-shear-wave-velocity areas may indicate both saturated, unconsolidated sands and low-rigidity clays. Via a polynomial approximation, soil sub-types of sand, silt and clay can be estimated by a cross-plot of S-wave velocity and resistivity. We confirm that existent boring log data fit reasonably well with the polynomial approximation where 2/3 of soil samples fall within their respective bounds—this approach represents a new classification system that could be used for other mid-latitude, fine-grained deltas.

Fine-scale spatial distribution of orchid mycorrhizal fungi in the soil of host-rich grasslands.

PubMed

Voyron, Samuele; Ercole, Enrico; Ghignone, Stefano; Perotto, Silvia; Girlanda, Mariangela

2017-02-01

Mycorrhizal fungi are essential for the survival of orchid seedlings under natural conditions. The distribution of these fungi in soil can constrain the establishment and resulting spatial arrangement of orchids at the local scale, but the actual extent of occurrence and spatial patterns of orchid mycorrhizal (OrM) fungi in soil remain largely unknown. We addressed the fine-scale spatial distribution of OrM fungi in two orchid-rich Mediterranean grasslands by means of high-throughput sequencing of fungal ITS2 amplicons, obtained from soil samples collected either directly beneath or at a distance from adult Anacamptis morio and Ophrys sphegodes plants. Like ectomycorrhizal and arbuscular mycobionts, OrM fungi (tulasnelloid, ceratobasidioid, sebacinoid and pezizoid fungi) exhibited significant horizontal spatial autocorrelation in soil. However, OrM fungal read numbers did not correlate with distance from adult orchid plants, and several of these fungi were extremely sporadic or undetected even in the soil samples containing the orchid roots. Orchid mycorrhizal 'rhizoctonias' are commonly regarded as unspecialized saprotrophs. The sporadic occurrence of mycobionts of grassland orchids in host-rich stands questions the view of these mycorrhizal fungi as capable of sustained growth in soil. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Physical and chemical properties of soils under some wild Pistachio (Pistacia atlantica Desf) canopies in a semi-arid ecosystem, southwestern Iran.

NASA Astrophysics Data System (ADS)

Owliaie, Hamidreza

2010-05-01

Pistacia atlantica Desf. is one of the most important wild species in Zagros forests which is of high economical and environmental value. Sustainability of these forests primarily depends on soil quality and water availability. Study the relationships between trees and soil is one of the basic factors in management and planning of forests. Hence, this study was undertaken with the objective of assessing the effect of tree species on soil physical and chemical properties in a semi-arid region (Kohgilouye Province) in the southwestern part of Iran. The experimental design was a factorial 4×2 (4 depths and 2 distances) in a randomized complete block design with six replications. Soil samples (0-20, 20-40, 40-60 and 60-80 cm depth) were taken from beneath the tree crowns and adjacent open areas. Soil samples were analyzed for physical and chemical properties. The results showed that wild pistachio canopy increased mostly organic carbon, hydraulic conductivity, total N, SP, available K+, P (olsen), EC, EDTA extractable Fe2+ and Mn2+, while bulk density, CCE and DTPA extractable Cu2+ were decreased. Pistachio canopy had no significant effect on soil texture, Zn2+ and pH.

3D Bedrock Structure of Bornova Plain and Its surroundings (İzmir/Western Turkey)

NASA Astrophysics Data System (ADS)

Pamuk, Eren; Gönenç, Tolga; Özdağ, Özkan Cevdet; Akgün, Mustafa

2018-01-01

An earthquake record is needed on engineering bedrock to perform soil deformation analysis. This record could be obtained in different ways (seismographs on engineering bedrock; by the help of the soil transfer function; scenario earthquakes). S-wave velocity ( V s) profile must be known at least till engineering bedrock for calculating soil transfer functions true and completely. In addition, 2D or 3D soil, engineering-seismic bedrock models are needed for soil response analyses to be carried out. These models are used to determine changes in the amplitude and frequency content of earthquake waves depending on the seismic impedance from seismic bedrock to the ground surface and the basin effects. In this context, it is important to use multiple in situ geophysical techniques to create the soil-bedrock models. In this study, 2D and 3D soil-bedrock models of Bornova plain and its surroundings (Western Turkey), which are very risky in terms of seismicity, were obtained by combined survey of surface wave and microgravity methods. Results of the study show that the engineering bedrock depths in the middle part of Bornova plain range from 200 to 400 m and the southern and northern parts which are covered limestone and andesite show the engineering bedrock ( V s > 760 m/s) feature. In addition, seismic bedrock ( V s < 3000 m/s) depth changes from 550 to 1350 m. The predominant period values obtained from single station microtremor method change from 0.45 to 1.6 s while they are higher than 1 s in the middle part of Bornova plain where the basin is deeper. Bornova Plain has a very thick sediment units which have very low V s values above engineering bedrock. In addition, it is observed sudden changes at the interfaces of the layer in horizontal and vertical directions.

[Time-evolution study on the cation exchange in the process of reinforcing slip soil by laser-induced breakdown spectroscopy].

PubMed

Liu, Lu-Wen; Zeng, Wei-Li; Zhu, Xiang-Fei; Wu, Jin-Quan; Lin, Zhao-Xiang

2014-03-01

In the present paper, the time evolution study on slip soils treated by different proportions of ionic soil stabilizer (ISS) water solution was conducted by the LIBS system and the relationship between the cation exchange and such engineering properties of reinforcing soil as plasticity index, cohesive force and coefficient of compressibility were analyzed. The results showed that the cation exchange velocity of the proportion of 1:200 ISS reinforcing soil is the fastest among the three proportions (1:100, 1:200 and 1:300) and the modification effect of engineering performance index is quite obvious. These studies provide an experimental basis for the ISS applied to curing project, and monitoring geotechnical engineering performance by LIBS technology also provides a new way of thinking for the curing project monitoring.

Development and Validation of EPH Material Model for Engineered Roadway Soil

DTIC Science & Technology

2014-08-01

MODEL FOR ENGINEERED ROADWAY SOIL Ching Hsieh, PhD Altair Engineering Troy, MI Jianping Sheng, Ph.D. Jai Ramalingam System Engineering...0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing...of information if it does not display a currently valid OMB control number. 1 . REPORT DATE 11 AUG 2014 2. REPORT TYPE Journal Article 3. DATES

Microbial Life beneath a High Arctic Glacier†

PubMed Central

Skidmore, Mark L.; Foght, Julia M.; Sharp, Martin J.

2000-01-01

The debris-rich basal ice layers of a high Arctic glacier were shown to contain metabolically diverse microbes that could be cultured oligotrophically at low temperatures (0.3 to 4°C). These organisms included aerobic chemoheterotrophs and anaerobic nitrate reducers, sulfate reducers, and methanogens. Colonies purified from subglacial samples at 4°C appeared to be predominantly psychrophilic. Aerobic chemoheterotrophs were metabolically active in unfrozen basal sediments when they were cultured at 0.3°C in the dark (to simulate nearly in situ conditions), producing 14CO2 from radiolabeled sodium acetate with minimal organic amendment (≥38 μM C). In contrast, no activity was observed when samples were cultured at subfreezing temperatures (≤−1.8°C) for 66 days. Electron microscopy of thawed basal ice samples revealed various cell morphologies, including dividing cells. This suggests that the subglacial environment beneath a polythermal glacier provides a viable habitat for life and that microbes may be widespread where the basal ice is temperate and water is present at the base of the glacier and where organic carbon from glacially overridden soils is present. Our observations raise the possibility that in situ microbial production of CO2 and CH4 beneath ice masses (e.g., the Northern Hemisphere ice sheets) is an important factor in carbon cycling during glacial periods. Moreover, this terrestrial environment may provide a model for viable habitats for life on Mars, since similar conditions may exist or may have existed in the basal sediments beneath the Martian north polar ice cap. PMID:10919772

Summer cover crops reduce atrazine leaching to shallow groundwater in southern Florida.

PubMed

Potter, Thomas L; Bosch, David D; Joo, Hyun; Schaffer, Bruce; Muñoz-Carpena, Rafael

2007-01-01

At Florida's southeastern tip, sweet corn (Zea Mays) is grown commercially during winter months. Most fields are treated with atrazine (6-chloro-N-ethyl-N'-[1-methylethyl]-1,3,5-triazine-2,4-diamine). Hydrogeologic conditions indicate a potential for shallow groundwater contamination. This was investigated by measuring the parent compound and three degradates--DEA (6-chloro-N-[1-methylethyl]-1,3,5-triazine-2,4-diamine), DIA (6-chloro-N-ethyl)-1,3,5-triazine-2,4-diamine, and HA (6-hydroxy-N-[1-methylethyl]-1,3,5-triazine-2,4-diamine)--in water samples collected beneath sweet corn plots treated annually with the herbicide. During the study, a potential mitigation measure (i.e., the use of a cover crop, Sunn Hemp [Crotalaria juncea L.], during summer fallow periods followed by chopping and turning the crop into soil before planting the next crop) was evaluated. Over 3.5 yr and production of four corn crops, groundwater monitoring indicated leaching of atrazine, DIA, and DEA, with DEA accounting for more than half of all residues in most samples. Predominance of DEA, which increased after the second atrazine application, was interpreted as an indication of rapid and extensive atrazine degradation in soil and indicated that an adapted community of atrazine degrading organisms had developed. A companion laboratory study found a sixfold increase in atrazine degradation rate in soil after three applications. Groundwater data also revealed that atrazine and degradates concentrations were significantly lower in samples collected beneath cover crop plots when compared with concentrations below fallow plots. Together, these findings demonstrated a relatively small although potentially significant risk for leaching of atrazine and its dealkylated degradates to groundwater and that the use of a cover crop like Sunn Hemp during summer months may be an effective mitigation measure.

1994 conceptual model of the carbon tetrachloride contamination in the 200 West Area at the Hanford Site

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

Rohay, V.J.

1994-08-01

Between 1955 and 1973, a total of 363,000 to 580,000 L (577,000 to kg) of liquid carbon tetrachloride, in mixtures with other organic and aqueous, actinide-bearing fluids, were discharged to the soil column at three disposal facilities -- the 216-Z-9 Trench, the 216-Z-lA TiTe Field, and the 216-Z-18 Crib -- in the 200 West Area at the Hanford Site. In the mid-1980`s, dissolved carbon tetrachloride was found in the uppermost aquifer beneath the disposal facilities, and in late 1990, the US Environmental Protection Agency and the Washington State Department of Ecology requested that the US Department of Energy proceed withmore » planning and implementation of an expedited response action (ERA) to minimize additional carbon tetrachloride contamination of the groundwater. In February 1992, soil vapor extraction was initiated to remove carbon tetrachloride from the unsaturated zone beneath these disposal facilities. By May 1994, a total of 10,560 L (16,790 kg) of carbon tetrachloride had been removed, amounting to an estimated 2% of the discharged inventory. In the spring of 1991, the Volatile Organic Compounds -- Arid Integrated Demonstration (VOC-Arid ID) program selected the carbon tetrachloride-contaminated site for demonstration and deployment of new technologies for evaluation and cleanup of volatile organic compounds and associated contaminants in soils and groundwater at arid sites. Site investigations conducted in support of both the ERA and the VOC-Arid ID have been integrated because of their shared objective to refine the conceptual model of the site and to promote efficiency. Site characterization data collected in fiscal year 1993 have supported and led to refinement of the conceptual model of the carbon tetrachloride site.« less

Nutrient transport and transformation beneath an infiltration basin

USGS Publications Warehouse

Sumner, D.M.; Rolston, D.E.; Bradner, L.A.

1998-01-01

Field experiments were conducted to examine nutrient transport and transformation beneath an infiltration basin used for the disposal of treated wastewater. Removal of nitrogen from infiltrating water by denitrification was negligible beneath the basin, probably because of subsurface aeration as a result of daily interruptions in basin loading. Retention of organic nitrogen in the upper 4.6 m of the unsaturated zone (water table depth of approximately 11 m) during basin loading resulted in concentrations of nitrate as much as 10 times that of the applied treated wastewater, following basin 'rest' periods of several weeks, which allowed time for mineralization and nitrification. Approximately 90% of the phosphorus in treated wastewater was removed within the upper 4.6 m of the subsurface, primarily by adsorption reactions, with abundant iron and aluminum oxyhydroxides occurring as soil coatings. A reduction in the flow rate of infiltrating water arriving at the water table may explain the accumulation of relatively coarse (>0.45 ??m), organic forms of nitrogen and phosphorus slightly below the water table. Mineralization and nitrification reactions at this second location of organic nitrogen accumulation contributed to concentrations of nitrate as much as three times that of the applied treated wastewater. Phosphorus, which accumulated below the water table, was immobilized by adsorption or precipitation reactions during basin rest periods.Field experiments were conducted to examine nutrient transport and transformation beneath an infiltration basin used for the disposal of treated wastewater. Removal of nitrogen from infiltrating water by denitrification was negligible beneath the basin, probably because of subsurface aeration as a result of daily interruptions in basin loading. Retention of organic nitrogen in the upper 4.6 m of the unsaturated zone (water table depth of approximately 11 m) during basin loading resulted in concentrations of nitrate as much as 10 times that of the applied treated wastewater, following basin 'rest' periods of several weeks, which allowed time for mineralization and nitrification. Approximately 90% of the phosphorus in treated wastewater was removed within the upper 4.6 m of the subsurface, primarily by adsorption reactions, with abundant iron and aluminum oxyhydroxides occurring as soil coatings. A reduction in the flow rate of infiltrating water arriving at the water table may explain the accumulation of relatively coarse (>0.45 ??m), organic forms of nitrogen and phosphorus slightly below the water table. Mineralization and nitrification reactions at this second location of organic nitrogen accumulation contributed to concentrations of nitrate as much as three times that of the applied treated wastewater. Phosphorus, which accumulated below the water table, was immobilized by adsorption or precipitation reactions during basin rest periods.

Evidence for chemical interference effect of an allelopathic plant on neighboring plant species: A field study.

PubMed

Arroyo, Antonio I; Pueyo, Yolanda; Giner, M Luz; Foronda, Ana; Sanchez-Navarrete, Pedro; Saiz, Hugo; Alados, Concepción L

2018-01-01

Many studies have reported the phytotoxicity of allelopathic compounds under controlled conditions. However, more field studies are required to provide realistic evidences for the significance of allelopathic interference in natural communities. We conducted a 2-years field experiment in a semiarid plant community (NE Spain). Specifically, we planted juvenile individuals and sowed seeds of Salsola vermiculata L., Lygeum spartum L. and Artemisia herba-alba Asso. (three co-dominant species in the community) beneath adult individuals of the allelopathic shrub A. herba-alba, and assessed the growth, vitality, seed germination and seedling survival of those target species with and without the presence of chemical interference by the incorporation of activated carbon (AC) to the soil. In addition, juveniles and seeds of the same three target species were planted and sown beneath the canopy of adults of S. vermiculata (a shrub similar to A. herba-alba, but non-allelopathic) and in open bare soil to evaluate whether the allelopathic activity of A. herba-alba modulates the net outcome of its interactions with neighboring plants under contrasting abiotic stress conditions. We found that vitality of A. herba-alba juveniles was enhanced beneath A. herba-alba individuals when AC was present. Furthermore, we found that the interaction outcome in A. herba-alba microsite was neutral, whereas a positive outcome was found for S. vermiculata microsite, suggesting that allelopathy may limit the potential facilitative effects of the enhanced microclimatic conditions in A. herba-alba microsite. Yet, L. spartum juveniles were facilitated in A. herba-alba microsite. The interaction outcome in A. herba-alba microsite was positive under conditions of very high abiotic stress, indicating that facilitative interactions predominated over the interference of allelopathic plants under those conditions. These results highlight that laboratory studies can overestimate the significance of allelopathy in nature, and consequently, results obtained under controlled conditions should be interpreted carefully.

Evidence for chemical interference effect of an allelopathic plant on neighboring plant species: A field study

PubMed Central

Pueyo, Yolanda; Giner, M. Luz; Foronda, Ana; Sanchez-Navarrete, Pedro; Saiz, Hugo; Alados, Concepción L.

2018-01-01

Many studies have reported the phytotoxicity of allelopathic compounds under controlled conditions. However, more field studies are required to provide realistic evidences for the significance of allelopathic interference in natural communities. We conducted a 2-years field experiment in a semiarid plant community (NE Spain). Specifically, we planted juvenile individuals and sowed seeds of Salsola vermiculata L., Lygeum spartum L. and Artemisia herba-alba Asso. (three co-dominant species in the community) beneath adult individuals of the allelopathic shrub A. herba-alba, and assessed the growth, vitality, seed germination and seedling survival of those target species with and without the presence of chemical interference by the incorporation of activated carbon (AC) to the soil. In addition, juveniles and seeds of the same three target species were planted and sown beneath the canopy of adults of S. vermiculata (a shrub similar to A. herba-alba, but non-allelopathic) and in open bare soil to evaluate whether the allelopathic activity of A. herba-alba modulates the net outcome of its interactions with neighboring plants under contrasting abiotic stress conditions. We found that vitality of A. herba-alba juveniles was enhanced beneath A. herba-alba individuals when AC was present. Furthermore, we found that the interaction outcome in A. herba-alba microsite was neutral, whereas a positive outcome was found for S. vermiculata microsite, suggesting that allelopathy may limit the potential facilitative effects of the enhanced microclimatic conditions in A. herba-alba microsite. Yet, L. spartum juveniles were facilitated in A. herba-alba microsite. The interaction outcome in A. herba-alba microsite was positive under conditions of very high abiotic stress, indicating that facilitative interactions predominated over the interference of allelopathic plants under those conditions. These results highlight that laboratory studies can overestimate the significance of allelopathy in nature, and consequently, results obtained under controlled conditions should be interpreted carefully. PMID:29474430

Tree species effects on pathogen-suppressive capacities of soil bacteria across two tropical dry forests in Costa Rica.

PubMed

Becklund, Kristen; Powers, Jennifer; Kinkel, Linda

2016-11-01

Antibiotic-producing bacteria in the genus Streptomyces can inhibit soil-borne plant pathogens, and have the potential to mediate the impacts of disease on plant communities. Little is known about how antibiotic production varies among soil communities in tropical forests, despite a long history of interest in the role of soil-borne pathogens in these ecosystems. Our objective was to determine how tree species and soils influence variation in antibiotic-mediated pathogen suppression among Streptomyces communities in two tropical dry forest sites (Santa Rosa and Palo Verde). We targeted tree species that co-occur in both sites and used a culture-based functional assay to quantify pathogen-suppressive capacities of Streptomyces communities beneath 50 focal trees. We also measured host-associated litter and soil element concentrations as potential mechanisms by which trees may influence soil microbes. Pathogen-suppressive capacities of Streptomyces communities varied within and among tree species, and inhibitory phenotypes were significantly related to soil and litter element concentrations. Average proportions of inhibitory Streptomyces in soils from the same tree species varied between 1.6 and 3.3-fold between sites. Densities and proportions of pathogen-suppressive bacteria were always higher in Santa Rosa than Palo Verde. Our results suggest that spatial heterogeneity in the potential for antibiotic-mediated disease suppression is shaped by tree species, site, and soil characteristics, which could have significant implications for understanding plant community composition and diversity in tropical dry forests.

Feasibility of biochar application on a landfill final cover-a review on balancing ecology and shallow slope stability.

PubMed

Chen, Xun-Wen; Wong, James Tsz-Fung; Ng, Charles Wang-Wai; Wong, Ming-Hung

2016-04-01

Due to the increasing concerns on global warming, scarce land for agriculture, and contamination impacts on human health, biochar application is being considered as one of the possible measures for carbon sequestration, promoting higher crop yield and contamination remediation. Significant amount of researches focusing on these three aspects have been conducted during recent years. Biochar as a soil amendment is effective in promoting plant performance and sustainability, by enhancing nutrient bioavailability, contaminants immobilization, and microbial activities. The features of biochar in changing soil physical and biochemical properties are essential in affecting the sustainability of an ecosystem. Most studies showed positive results and considered biochar application as an effective and promising measure for above-mentioned interests. Bio-engineered man-made filled slope and landfill slope increasingly draw the attention of geologists and geotechnical engineers. With increasing number of filled slopes, sustainability, low maintenance, and stability are the major concerns. Biochar as a soil amendment changes the key factors and parameters in ecology (plant development, soil microbial community, nutrient/contaminant cycling, etc.) and slope engineering (soil weight, internal friction angle and cohesion, etc.). This paper reviews the studies on the production, physical and biochemical properties of biochar and suggests the potential areas requiring study in balancing ecology and man-made filled slope and landfill cover engineering. Biochar-amended soil should be considered as a new type of soil in terms of soil mechanics. Biochar performance depends on soil and biochar type which imposes challenges to generalize the research outcomes. Aging process and ecotoxicity studies of biochar are strongly required.

Application of positive matrix factorization to identify potential sources of PAHs in soil of Dalian, China.

PubMed

Wang, Degao; Tian, Fulin; Yang, Meng; Liu, Chenlin; Li, Yi-Fan

2009-05-01

Soil derived sources of polycyclic aromatic hydrocarbons (PAHs) in the region of Dalian, China were investigated using positive matrix factorization (PMF). Three factors were separated based on PMF for the statistical investigation of the datasets both in summer and winter. These factors were dominated by the pattern of single sources or groups of similar sources, showing seasonal and regional variations. The main sources of PAHs in Dalian soil in summer were the emissions from coal combustion average (46%), diesel engine (30%), and gasoline engine (24%). In winter, the main sources were the emissions from coal-fired boiler (72%), traffic average (20%), and gasoline engine (8%). These factors with strong seasonality indicated that coal combustion in winter and traffic exhaust in summer dominated the sources of PAHs in soil. These results suggested that PMF model was a proper approach to identify the sources of PAHs in soil.

Engineering properties of stabilized subgrade soils for implementation of the AASHTO 2002 pavement design guide.

DOT National Transportation Integrated Search

2009-06-01

A comprehensive laboratory study was undertaken to determine engineering properties of cementitiously stabilized common subgrade soils in Oklahoma for the design of roadway pavements in accordance with the AASHTO 2002 Mechanistic-Empirical Pavement D...

Effect of top soil wettability on water evaporation and plant growth.

PubMed

Gupta, Bharat; Shah, D O; Mishra, Brijesh; Joshi, P A; Gandhi, Vimal G; Fougat, R S

2015-07-01

In general, agricultural soil surfaces being hydrophilic in nature get easily wetted by water. The water beneath the soil moves through capillary effect and comes to the surface of the soil and thereafter evaporates into the surrounding air due to atmospheric conditions such as sunlight, wind current, temperature and relative humidity. To lower the water loss from soil, an experiment was designed in which a layer of hydrophobic soil was laid on the surface of ordinary hydrophilic soil. This technique strikingly decreased loss of water from the soil. The results indicated that the evaporation rate significantly decreased and 90% of water was retained in the soil in 83 h by the hydrophobic layer of 2 cm thickness. A theoretical calculation based on diffusion of water vapour (gas phase) through hydrophobic capillaries provide a meaningful explanation of experimental results. A greater retention of water in the soil by this approach can promote the growth of plants, which was confirmed by growing chick pea (Cicer arietinum) plants and it was found that the length of roots, height of shoot, number of branches, number of leaves, number of secondary roots, biomass etc. were significantly increased upon covering the surface with hydrophobic soil in comparison to uncovered ordinary hydrophilic soil of identical depth. Such approach can also decrease the water consumption by the plants particularly grown indoors in residential premises, green houses and poly-houses etc. and also can be very useful to prevent water loss and enhance growth of vegetation in semi-arid regions. Copyright © 2015 Elsevier Inc. All rights reserved.

Responses of soil and water chemistry to mountain pine beetle induced tree mortality in Grand County, Colorado, USA

USGS Publications Warehouse

Clow, David W.; Rhoades, Charles; Briggs, Jenny S.; Caldwell, Megan K.; Lewis, William M.

2011-01-01

Pine forest in northern Colorado and southern Wyoming, USA, are experiencing the most severe mountain pine beetle epidemic in recorded history, and possible degradation of drinking-water quality is a major concern. The objective of this study was to investigate possible changes in soil and water chemistry in Grand County, Colorado in response to the epidemic, and to identify major controlling influences on stream-water nutrients and C in areas affected by the mountain pine beetle. Soil moisture and soil N increased in soils beneath trees killed by the mountain pine beetle, reflecting reduced evapotranspiration and litter accumulation and decay. No significant changes in stream-water NO3-">NO3- or dissolved organic C were observed; however, total N and total P increased, possibly due to litter breakdown or increased productivity related to warming air temperatures. Multiple-regression analyses indicated that % of basin affected by mountain pine beetles had minimal influence on stream-water NO3-">NO3- and dissolved organic C; instead, other basin characteristics, such as percent of the basin classified as forest, were much more important.

Plant-soil feedback in East-African savanna trees.

PubMed

Rutten, Gemma; Prati, Daniel; Hemp, Andreas; Fischer, Markus

2016-02-01

Research in savannas has focused on tree-grass interactions, whereas tree species coexistence received little attention. A leading hypothesis to explain tree coexistence is the Janzen-Connell model, which proposes an accumulation of host-specific enemies, e.g., soil organisms. While it has been shown in several non-savanna case studies that seedlings dispersed away from the mother perform better than seedlings that stay close (home-away effect), few studies tested whether foreign seedling species can replace own seedlings under conspecific adults (replacement effect). Some studies additionally tested for negative effects of conspecific biota (conspecific effect) to demonstrate the accumulation of enemies. We tested these effects by reciprocally growing seedlings of four tree species on soil collected beneath adults of all species, with and without applying a soil sterilization treatment. We found negative home-away effects suggesting that dispersal is advantageous and negative replacement effects suggesting species replacement under adults. While negative conspecific effects indicate accumulated enemies, positive heterospecific effects indicate an accumulation of mutualists rather than enemies for some species. We suggest that plant-soil feedbacks may well contribute to tree coexistence in savannas due to both negative conspecific and positive heterospecific feedbacks.

Yogi the rock - 3D

NASA Technical Reports Server (NTRS)

1997-01-01

Yogi, a rock taller than rover Sojourner, is the subject of this image, taken in stereo by the deployed Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. The soil in the foreground has been the location of multiple soil mechanics experiments performed by Sojourner's cleated wheels. Pathfinder scientists were able to control the force inflicted on the soil beneath the rover's wheels, giving them insight into the soil's mechanical properties. The soil mechanics experiments were conducted after this image was taken.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

Dissolved free and combined amino acids in surface runoff and drainage waters from drained and undrained grassland under different fertilizer management.

PubMed

Hawkins, Jane M B; Scholefield, David; Braven, Jim

2006-08-15

Organic matter is a valuable resource on which the sustainability and productivity of soils relies heavily. Thus, it is important to understand the mechanisms for the loss of organic compounds from soil. It is also essential to determine how these losses can be minimized, especially those resulting from anthropogenic activity. Grazed grassland lysimeters (1 hectare) were used to examine the contribution and distribution patterns of dissolved free and combined amino acids to dissolved organic nitrogen and carbon in surface runoff and drainage waters from a grassland soil over three winter drainage periods. The waters were collected from soils beneath drained and undrained permanent ryegrass swards, receiving 0 and 280 kg ha(-1) year(-1) mineral nitrogen (N) input. Total dissolved free amino acid (DFAA) and dissolved combined amino acid (DCAA) concentrations ranged between 1.9 nM and 6.1 microM and between 1.3 and 87 microM, respectively. Although addition of mineral N fertilizer increased both DFAA and DCAA concentrations in waters, there was no detectable effect of soil hydrology or fertilizer addition on distribution patterns.

Geotechnical Engineering in US Elementary Schools

ERIC Educational Resources Information Center

Suescun-Florez, Eduardo; Iskander, Magued; Kapila, Vikram; Cain, Ryan

2013-01-01

This paper reports on the results of several geotechnical engineering-related science activities conducted with elementary-school students. Activities presented include soil permeability, contact stress, soil stratigraphy, shallow and deep foundations, and erosion in rivers. The permeability activity employed the LEGO NXT platform for data…

ONSITE ENGINEERING REPORT FOR SOLIDIFICATION/ STABILIZATION TREATMENT TESTING OF CONTAMINATED SOILS

EPA Science Inventory

The EPA's Office of Solid Waste and Emergency Response (OSWER) is currently developing land disposal restrictions (LDRs) for contaminated soil and debris (CS&D). The Office of Research and Development, through its Risk Reduction Engineering Laboratory (RREL), is providing support...

USCS and the USDA Soil Classification System: Development of a Mapping Scheme

DTIC Science & Technology

2015-03-01

important to human daily living. A variety of disciplines (geology, agriculture, engineering, etc.) require a sys- tematic categorization of soil, detailing...it is often important to also con- sider parameters that indicate soil strength. Two important properties used for engineering-related problems are...that many textural clas- sification systems were developed to meet specifics needs. In agriculture, textural classification is used to determine crop

ENGINEERING BULLETIN: IN SITU SOIL FLUSHING

EPA Science Inventory

In situ soil flushing is the extraction of contaminants from the soil with water or other suitable aqueous solutions. Soil flushing is accomplished by passing the extraction fluid through in-place soils using an injection or infiltration process. Extraction fluids must be recover...

Rice Field Geochemistry and Hydrology: An Explanation for Why Groundwater Irrigated Fields in Bangladesh are Net Sinks of Arsenic from Groundwater

PubMed Central

Neumann, Rebecca B.; St. Vincent, Allison P.; Roberts, Linda C.; Badruzzaman, A. Borhan M.; Ali, M. Ashraf; Harvey, Charles F.

2011-01-01

Irrigation of rice fields in Bangladesh with arsenic-contaminated groundwater transfers tens of cubic kilometers of water and thousands of tons of arsenic from aquifers to rice fields each year. Here we combine observations of infiltration patterns with measurements of porewater chemical composition from our field site in Munshiganj Bangladesh to characterize the mobility of arsenic in soils beneath rice fields. We find that very little arsenic delivered by irrigation returns to the aquifer, and that recharging water mobilizes little, if any, arsenic from rice field subsoils. Arsenic from irrigation water is deposited on surface soils and sequestered along flow paths that pass through bunds, the raised soil boundaries around fields. Additionally, timing of flow into bunds limits the transport of biologically available organic carbon from rice fields into the subsurface where it could stimulate reduction processes that mobilize arsenic from soils and sediments. Together, these results explain why groundwater irrigated rice fields act as net sinks of arsenic from groundwater. PMID:21332196

Discovering the Giant Nest Architecture of Grass-Cutting Ants, Atta capiguara (Hymenoptera, Formicidae)

PubMed Central

Forti, Luiz Carlos; Protti de Andrade, Ana Paula; Camargo, Roberto da Silva; Caldato, Nadia; Moreira, Aldenise Alves

2017-01-01

Atta capiguara is a grass-cutting ant species frequently found in Cerrado biome. However, little is known about the giant nest architecture of this ant. In this study, we investigated the architecture of three A. capiguara nests from a fragment of Cerrado in Botucatu, São Paulo, Brazil. Casts were made of the nests by filling them with cement to permit better visualization of internal structures such as chambers and tunnels. After excavation, the depth and dimensions (length, width, and height) of the chambers were measured. The results showed the shape of Atta capiguara nests consisting of mounds of loose soil with unique features resembling a conic section. The fungus chambers were found distant from the mound of loose soil and were spaced apart and distributed laterally at the soil profile. The waste chambers were located beneath the largest mound of loose soil. Both the fungus and waste chambers were separated and distant. Our study contributes to a better understanding of the so far unknown nest architecture of the grass-cutting ant A. capiguara. PMID:28350352

Native Michigan plants stimulate soil microbial species changes and PAH remediation at a legacy steel mill.

PubMed

Thomas, John C; Cable, Edward; Dabkowski, Robert T; Gargala, Stephanie; McCall, Daniel; Pangrazzi, Garett; Pierson, Adam; Ripper, Mark; Russell, Donald K; Rugh, Clayton L

2013-01-01

A 1.3-acre phytoremediation site was constructed to mitigate polyaromatic hydrocarbon (PAH) contamination from a former steel mill in Michigan. Soil was amended with 10% (v/v) compost and 5% (v/v) poultry litter. The site was divided into twelve 11.89 m X 27.13 m plots, planted with approximately 35,000 native Michigan perennials, and soils sampled for three seasons. Soil microbial density generally increased in subplots of Eupatorium perfoliatum (boneset), Aster novae-angliae (New England aster), Andropogon gerardii (big bluestem), and Scirpus atrovirens (green bulrush) versus unplanted subplots. Using enumeration assays with root exudates, PAH degrading bacteria were greatest in soils beneath plants. Initially predominant, Arthrobacter were found capable of degrading a PAH cocktail in vitro, especially upon the addition of root exudate. Growth of some Arthrobacter isolates was stimulated by root exudate. The frequency of Arthrobacter declined in planted subplots with a concurrent increase in other species, including secondary PAH degraders Bacillus and Nocardioides. In subplots supporting only weeds, an increase in Pseudomonas density and little PAH removal were observed. This study supports the notion that a dynamic interplay between the soil, bacteria, and native plant root secretions likely contributes to in situ PAH phytoremediation.

Streambeds Merit Recognition as a Scientific Discipline

NASA Astrophysics Data System (ADS)

Constantz, J. E.

2016-12-01

Streambeds are generally viewed as simply sediments beneath streams, sediments topping alluvial aquifers, or sediments housing aquatic life, rather than as distinct geographic features comparable to soils and surficial geologic formations within watersheds. Streambeds should be viewed as distinct elements within watersheds, e.g., as akin to soils. In this presentation, streambeds are described as central features in watersheds, cycling water between the surface and underlying portions of the watershed. Regarding their kinship to soils, soils are often described as surficial sediments largely created by atmospheric weathering of underlying geologic parent material, and similarly, streambeds should be described as submerged sediments largely created by streamflow modification of underlying geologic parent material. Thus, streambeds are clearly overdue for recognition as their own scientific discipline along side other well-recognized disciplines within watersheds; however, slowing progress in this direction, the point is often made that hyporheic zones should be considered comparable to streambeds, but this is as misguided as equating unsaturated zones to soils. Streambeds and soils are physical geographic features of relatively constant volume, while hyporheic and unsaturated zones are hydrologic features of varying volume. Expanded upon in this presentation, 'Streambed Science' is proposed for this discipline, which will require both a well-designed protocol to physically characterize streambeds as well as development of streambed taxonomy, for suitable recognition as an independent discipline within watersheds.

Relationships between basic soils-engineering equations and basic ground-water flow equations

USGS Publications Warehouse

Jorgensen, Donald G.

1980-01-01

The many varied though related terms developed by ground-water hydrologists and by soils engineers are useful to each discipline, but their differences in terminology hinder the use of related information in interdisciplinary studies. Equations for the Terzaghi theory of consolidation and equations for ground-water flow are identical under specific conditions. A combination of the two sets of equations relates porosity to void ratio and relates the modulus of elasticity to the coefficient of compressibility, coefficient of volume compressibility, compression index, coefficient of consolidation, specific storage, and ultimate compaction. Also, transient ground-water flow is related to coefficient of consolidation, rate of soil compaction, and hydraulic conductivity. Examples show that soils-engineering data and concepts are useful to solution of problems in ground-water hydrology.

Heterogeneity of soil surface temperature induced by xerophytic shrub in a revegetated desert ecosystem, northwestern China

NASA Astrophysics Data System (ADS)

Zhang, Ya-Feng; Wang, Xin-Ping; Pan, Yan-Xia; Hu, Rui; Zhang, Hao

2013-06-01

Variation characteristics of the soil surface temperature induced by shrub canopy greatly affects the near-surface biological and biochemical processes in desert ecosystems. However, information regarding the effects of shrub upon the heterogeneity of soil surface temperature is scarce. Here we aimed to characterize the effects of shrub ( Caragana korshinskii) canopy on the soil surface temperature heterogeneity at areas under shrub canopy and the neighbouring bare ground. Diurnal variations of soil surface temperature were measured at areas adjacent to the shrub base (ASB), beneath the midcanopy (BMC), and in the bare intershrub spaces (BIS) at the eastern, southern, western and northern aspects of shrub, respectively. Results indicated that diurnal mean soil surface temperature under the C. korshinskii canopy (ASB and BMC) was significantly lower than in the BIS, with the highest in the BIS, followed by the BMC and ASB. The diurnal maximum and diurnal variations of soil surface temperatures under canopy vary strongly with different aspects of shrub with the diurnal variation in solar altitude, which could be used as cues to detect safe sites for under-canopy biota. A significant empirical linear relationship was found between soil surface temperature and solar altitude, suggesting an empirical predicator that solar altitude can serve for soil surface temperature. Lower soil surface temperatures under the canopy than in the bare intershrub spaces imply that shrubs canopy play a role of `cool islands' in the daytime in terms of soil surface temperature during hot summer months in the desert ecosystems characterized by a mosaic of sparse vegetation and bare ground.

ENGINEERING ISSUE: TECHNOLOGY ALTERNATIVES FOR THE REMEDIATION OF PCB-CONTAMINATED SOIL AND SEDIMENT

EPA Science Inventory

Because of the increased need for Superfund decision-makers to have a working knowledge of the remedial capabilities available to treat soil and sediment contaminated with polychlorinated biphenyls (PCBs), the Superfund Engineering Forum has identified remediation of PCB-contamin...

Nanoscale interactions between engineered nanomaterials and black carbon (Biochar) in soil

USDA-ARS?s Scientific Manuscript database

Engineered nanomaterials (NMs) enter agricultural soils directly as additives in agrichemical formulations1 and indirectly as contaminants in municipal sewage sludge.2 NIFA has a vested interest in developing predictive models for the fate and nanotoxicity of NMs in agroecosystems. An understanding ...

The soil management assessment framework: A potential soil health assessment tool

USDA-ARS?s Scientific Manuscript database

The Soil Management Assessment Framework (SMAF) was developed in the 1990s utilizing Systems Engineering and Ecology experiences with scoring functions to normalize disparate soil physical, chemical, and biological indicator data representing critical properties and processes associated with soil qu...

Above the weathering front: contrasting approaches to the study and classification of weathered mantle

NASA Astrophysics Data System (ADS)

Ehlen, Judy

2005-04-01

Weathered mantle comprises the materials above bedrock and below the soil. It can vary in thickness from millimeters to hundreds of meters, depending primarily on climate and parent material. Study of the weathered mantle comes within the realms of four disciplines: geology, geomorphology, soil science, and civil engineering, each of which uses a different approach to describe and classify the material. The approaches of engineers, geomorphologists, and geologists are contrasted and compared using example papers from the published literature. Soil scientists rarely study the weathering profile as such, and instead concentrate upon soil-forming processes and spatial distribution primarily in the solum. Engineers, including engineering geologists, study the stability and durability of the weathered mantle and the strength of the materials using sophisticated procedures to classify weathered materials, but their approach tends to be one-dimensional. Furthermore, they believe that the study of mineralogy and chemistry is not useful. Geomorphologists deal with weathering in terms of process—how the weathered mantle is formed—and with respect to landform evolution using a spatial approach. Geologists tend to ignore the weathered mantle because it is not bedrock, or to study its mineralogy and/or chemistry in the laboratory. I recommend that the approaches of the various disciplines be integrated—geomorphologists and geologists should consider using engineering weathering classifications, and geologists should adopt a spatial perspective to weathering, as should engineers and engineering geologists.

A study of the effectiveness of the use of gypsum and volcanic ash against the stability of clay soil in terms of UCT and CBR values

NASA Astrophysics Data System (ADS)

Roesyanto; Iskandar, R.; Hastuty, IP; Lubis, AIU

2018-02-01

Soil stabilization is an effort to improve engineering properties of soil. The conventional soil stabilization is by adding additives to the soil such as Portland cement, lime, and bitumen. The clay stabilization research was done by adding gypsum and volcanic ash. The research purposes were to find out the value of engineering properties of clay due to the addition of 2% gypsum and 2% - 15% volcanic ash. The soil was classified as Clay - Low Plasticity (CL) based on USCS and was classified as A-7-6 (10) based on AASHTO classification system. The UCT values of original soil and original soil plus 2% gypsum were 1.40 kg/cm2 and 1.66 kg/cm2 respectively. The CBR soaked and unsoaked values of original soil were 4.44% and 6.28% correspondingly. Meanwhile, CBR soaked and CBR unsoaked values of original soil plus 2% gypsum were 6.74% and 8.02% respectively. The research results showed that the additives materials of gypsum and volcanic ash improved the engineering properties of clay. The UCT result from the stabilized soil by 2% gypsum and 10% volcanic ash gave value of 2.79 kg/cm2 (increased 99.28% from original soil). For CBR test, the most effective mixture were in variation of 2% gypsum and 9% volcanic ash which gave value of 9.07% (104.27% increase from original soil) for CBR soaked and 10.29% (63.85% increase from original soil) for CBR unsoaked. The stabilized soil with 2% gypsum and 9% volcanic ash was classified as CL based on USCS and was classified as A-6 (4) based on AASHTO classification system.

Soil ecosystem functioning under climate change: plant species and community effects.

PubMed

Kardol, Paul; Cregger, Melissa A; Campany, Courtney E; Classen, Aimee T

2010-03-01

Feedbacks of terrestrial ecosystems to atmospheric and climate change depend on soil ecosystem dynamics. Soil ecosystems can directly and indirectly respond to climate change. For example, warming directly alters microbial communities by increasing their activity. Climate change may also alter plant community composition, thus indirectly altering the soil communities that depend on their inputs. To better understand how climate change may directly and indirectly alter soil ecosystem functioning, we investigated old-field plant community and soil ecosystem responses to single and combined effects of elevated [CO2], warming, and precipitation in Tennessee (USA). Specifically, we collected soils at the plot level (plant community soils) and beneath dominant plant species (plant-specific soils). We used microbial enzyme activities and soil nematodes as indicators for soil ecosystem functioning. Our study resulted in two main findings: (1) Overall, while there were some interactions, water, relative to increases in [CO2] and warming, had the largest impact on plant community composition, soil enzyme activity, and soil nematodes. Multiple climate-change factors can interact to shape ecosystems, but in our study, those interactions were largely driven by changes in water. (2) Indirect effects of climate change, via changes in plant communities, had a significant impact on soil ecosystem functioning, and this impact was not obvious when looking at plant community soils. Climate-change effects on enzyme activities and soil nematode abundance and community structure strongly differed between plant community soils and plant-specific soils, but also within plant-specific soils. These results indicate that accurate assessments of climate-change impacts on soil ecosystem functioning require incorporating the concurrent changes in plant function and plant community composition. Climate-change-induced shifts in plant community composition will likely modify or counteract the direct impact of atmospheric and climate change on soil ecosystem functioning, and hence, these indirect effects should be taken into account when predicting the manner in which global change will alter ecosystem functioning.

Increased temperature and altered summer precipitation have differential effects on biological soil crusts in a dryland ecosystem

USGS Publications Warehouse

Johnson, Shannon L.; Kuske, Cheryl R.; Carney, Travis D.; Housman, David C.; Gallegos-Graves, La Verne; Belnap, Jayne

2012-01-01

Biological soil crusts (biocrusts) are common and ecologically important members of dryland ecosystems worldwide, where they stabilize soil surfaces and contribute newly fixed C and N to soils. To test the impacts of predicted climate change scenarios on biocrusts in a dryland ecosystem, the effects of a 2–3 °C increase in soil temperature and an increased frequency of smaller summer precipitation events were examined in a large, replicated field study conducted in the cold desert of the Colorado Plateau, USA. Surface soil biomass (DNA concentration), photosynthetically active cyanobacterial biomass (chlorophyll a concentration), cyanobacterial abundance (quantitative PCR assay), and bacterial community composition (16S rRNA gene sequencing) were monitored seasonally over 2 years. Soil microbial biomass and bacterial community composition were highly stratified between the 0–2 cm depth biocrusts and 5–10 cm depth soil beneath the biocrusts. The increase in temperature did not have a detectable effect on any of the measured parameters over 2 years. However, after the second summer of altered summer precipitation pattern, significant declines occurred in the surface soil biomass (avg. DNA concentration declined 38%), photosynthetic cyanobacterial biomass (avg. chlorophyll a concentration declined 78%), cyanobacterial abundance (avg. gene copies g−1 soil declined 95%), and proportion of Cyanobacteria in the biocrust bacterial community (avg. representation in sequence libraries declined 85%). Biocrusts are important contributors to soil stability, soil C and N stores, and plant performance, and the loss or reduction of biocrusts under an altered precipitation pattern associated with climate change could contribute significantly to lower soil fertility and increased erosion and dust production in dryland ecosystems at a regional scale.

Genetically engineered Pseudomonas putida X3 strain and its potential ability to bioremediate soil microcosms contaminated with methyl parathion and cadmium.

PubMed

Zhang, Rong; Xu, Xingjian; Chen, Wenli; Huang, Qiaoyun

2016-02-01

A multifunctional Pseudomonas putida X3 strain was successfully engineered by introducing methyl parathion (MP)-degrading gene and enhanced green fluorescent protein (EGFP) gene in P. putida X4 (CCTCC: 209319). In liquid cultures, the engineered X3 strain utilized MP as sole carbon source for growth and degraded 100 mg L(-1) of MP within 24 h; however, this strain did not further metabolize p-nitrophenol (PNP), an intermediate metabolite of MP. No discrepancy in minimum inhibitory concentrations (MICs) to cadmium (Cd), copper (Cu), zinc (Zn), and cobalt (Co) was observed between the engineered X3 strain and its host strain. The inoculated X3 strain accelerated MP degradation in different polluted soil microcosms with 100 mg MP kg(-1) dry soil and/or 5 mg Cd kg(-1) dry soil; MP was completely eliminated within 40 h. However, the presence of Cd in the early stage of remediation slightly delayed MP degradation. The application of X3 strain in Cd-contaminated soil strongly affected the distribution of Cd fractions and immobilized Cd by reducing bioavailable Cd concentrations with lower soluble/exchangeable Cd and organic-bound Cd. The inoculated X3 strain also colonized and proliferated in various contaminated microcosms. Our results suggested that the engineered X3 strain is a potential bioremediation agent showing competitive advantage in complex contaminated environments.

Fate of effluent-borne contaminants beneath septic tank drainfields overlying a Karst aquifer.

PubMed

Katz, Brian G; Griffin, Dale W; McMahon, Peter B; Harden, Harmon S; Wade, Edgar; Hicks, Richard W; Chanton, Jeffrey P

2010-01-01

Groundwater quality effects from septic tanks were investigated in the Woodville Karst Plain, an area that contains numerous sinkholes and a thin veneer of sands and clays overlying the Upper Floridan aquifer (UFA). Concerns have emerged about elevated nitrate concentrations in the UFA, which is the source of water supply in this area of northern Florida. At three sites during dry and wet periods in 2007-2008, water samples were collected from the septic tank, shallow and deep lysimeters, and drainfield and background wells in the UFA and analyzed for multiple chemical indicators including nutrients, nitrate isotopes, organic wastewater compounds (OWCs), pharmaceutical compounds, and microbiological indicators (bacteria and viruses). Median NO3-N concentration in groundwater beneath the septic tank drainfields was 20 mg L(-1) (8.0-26 mg L(-1)). After adjusting for dilution, about 25 to 40% N loss (from denitrification, ammonium sorption, and ammonia volatilization) occurs as septic tank effluent moves through the unsaturated zone to the water table. Nitrogen loading rates to groundwater were highly variable at each site (3.9-12 kg N yr(-1)), as were N and chloride depth profiles in the unsaturated zone. Most OWCs and pharmaceutical compounds were highly attenuated beneath the drainfields; however, five Cs (caffeine, 1,7-dimethylxanthine, phenol, galaxolide, and tris(dichloroisotopropyl)phosphate) and two pharmaceutical compounds (acetaminophen and sulfamethoxazole) were detected in groundwater samples. Indicator bacteria and human enteric viruses were detected in septic tank effluent samples but only intermittently in soil water and groundwater. Contaminant movement to groundwater beneath each septic tank system also was related to water use and differences in lithology at each site.

Getting beneath the Veil of Effective Schools: Evidence from New York City. NBER Working Paper No. 17632

ERIC Educational Resources Information Center

Dobbie, Will; Fryer, Roland G., Jr.

2011-01-01

Charter schools were developed, in part, to serve as an R&D engine for traditional public schools, resulting in a wide variety of school strategies and outcomes. In this paper, we collect unparalleled data on the inner-workings of 35 charter schools and correlate these data with credible estimates of each school's effectiveness. We find that…

Engineering geology considerations for park planning, Antelope Island State Park, Davis County, Utah

USGS Publications Warehouse

Hecker, Suzanne; Case, William F.; King, Jon K.; Willis, Grant C.

2000-01-01

Report: 00-1 In the mid-1980s, historically high levels of Great Salt Lake caused damage to park facilities on Antelope Island and destroyed the causeway linking the park to the mainland. Information on the engineering geology of Antelope Islandcan be used to improve park facilities and reduce the risk from geologic hazards and poor construction conditions. Certain characteristics of the geologic environment need to be considered in park planning. During wet cycles, Great Salt Lake may reach static levels of 4,217 feet (1,285.3 m), and wave- and wind-elevated levels locally may reach 6.5 feet (2 m) higher. A probabilistic assessment of the earthquake ground-shaking hazard along the Wasatch Front indicates that peak ground accelerations of approximately 0.20 to 0.30 g have a one-in-ten chance of being exceeded in 50 years on the island. A slope-failure hazard exists locally in colluvial and Lake Bonneville deposits, along the modern shore, and beneath cliffs. Flash-flood and debris-flow hazards exist on alluvial fans. Areas in the southern two-thirds of the island may have a relatively high potential for radon emission. Particular soil types on the island may be expansive, compressible, erodible, impermeable, or susceptible to liquefaction or hydrocompaction. The distribution of most geologic hazards can be defined, and many locations on the island have conditions suitable for construction. Lacustrine sand and gravel deposits are wide-spread and have engineering characteristics that are generally favorable for foundations. However, facilities and roads built close to the modern shoreline may be susceptible to lake flooding and erosion, slope failures, shallow ground water, and burial by active sand dunes. Well-graded (poorly sorted) alluvial-fan deposits are generally most suitable for wastewater disposal, although they may be subject to flooding or be underlain by low-permeability, fine-grained lacustrine deposits.

Distribution of major herbicides in ground water of the United States

USGS Publications Warehouse

Barbash, Jack E.; Thelin, Gail P.; Kolpin, Dana W.; Gilliom, Robert J.

1999-01-01

Frequencies of detection at or above 0.01 microgram per liter in shallow ground water beneath agricultural areas during the NAWQA study were significantly correlated with agricultural use in those areas for atrazine, cyanazine, alachlor, and metolachlor (P<0.05; Spearman rank correlations), but not for simazine (P>0.05). In urban areas, overall frequencies of detection of these five herbicides in shallow ground water were positively correlated with their total nonagricultural use nationwide (P=0.026; simple linear correlation). Multivariate statistical analysis indicated that frequencies of detection in shallow ground water beneath agricultural areas were positively correlated with half-lives for transformation in aerobic soil and agricultural use of the compounds (P≤0.0001 for both parameters). Although frequencies of detection were not significantly correlated with their subsurface mobility (Koc; P=0.19) or the median well depths of the sampled networks (P=0.72), the range of Koc values among the five herbicides and the range of well depths were limited.

Soil engineering facilitates Downy brome (Bromus tectorum L.) growth - A case study

USDA-ARS?s Scientific Manuscript database

Some exotic plants are able to engineer new host soils and engender characteristics that potentially increase their growth. We hypothesized that this positive feedback may be a facet in the competitiveness of the exotic annual grass downy brome. Using rhizotrons in the greenhouse, we compared the gr...

Laboratory Assessment of the Mobility of Water-Dispersed Engineered Nanoparticles in a Red Soil (Ultisol)

EPA Science Inventory

Soils are major sinks of engineered nanoparticles (ENPs) as results of land applications of sewage sludge, accidental spills, or deliberate applications of ENPs (e.g., nano-pesticides). In this study, the transport behaviors of four widely used ENPs (titanium dioxide [TiO2], buck...

Creep behavior of soil nail walls in high plasticity index (PI) soils : technical report.

DOT National Transportation Integrated Search

2017-04-01

An aspect of particular concern in the Geotechnical Engineering Circular No. 7: Soil Nail Walls (i.e., the soil : nail wall manual and construction guidelines) is the creep behavior of soil nail systems in high-plasticity : clays. This research proje...

Structural changes of green roof growing substrate layer studied by X-ray CT

NASA Astrophysics Data System (ADS)

Jelinkova, Vladimira; Sacha, Jan; Dohnal, Michal; Snehota, Michal

2017-04-01

Increasing interest in green infrastructure linked with newly implemented legislation/rules/laws worldwide opens up research potential for field of soil hydrology. A better understanding of function of engineered soils involved in green infrastructure solutions such as green roofs or rain garden is needed. A soil layer is considered as a highly significant component of the aforesaid systems. In comparison with a natural soil, the engineered soil is assumed to be the more challenging case due to rapid structure changes early stages after its build-up. The green infrastructure efficiency depends on the physical and chemical properties of the soil, which are, in the case of engineered soils, a function of its initial composition and subsequent soil formation processes. The project presented in this paper is focused on fundamental processes in the relatively thick layer of engineered soil. The initial structure development, during which the pore geometry is altered by the growth of plant roots, water influx, solid particles translocation and other soil formation processes, is investigated with the help of noninvasive imaging technique  X-ray computed tomography. The soil development has been studied on undisturbed soil samples taken periodically from green roof test system during early stages of its life cycle. Two approaches and sample sizes were employed. In the first approach, undisturbed samples (volume of about 63 cm3) were taken each time from the test site and scanned by X-ray CT. In the second approach, samples (volume of about 630 cm3) were permanently installed at the test site and has been repeatedly removed to perform X-ray CT imaging. CT-derived macroporosity profiles reveal significant temporal changes of soil structure. Clogging of pores by fine particles and fissures development are two most significant changes that would affect the green roof system efficiency. This work has been supported by the Ministry of Education, Youth and Sports within National Sustainability Programme I, project number LO1605 and with financial support from the Czech Science Foundation under project number GAČR 17-21011S.

Seasonal dynamics of microbial community composition and function in oak canopy and open grassland soils

USGS Publications Warehouse

Waldrop, M.P.; Firestone, M.K.

2006-01-01

Soil microbial communities are closely associated with aboveground plant communities, with multiple potential drivers of this relationship. Plants can affect available soil carbon, temperature, and water content, which each have the potential to affect microbial community composition and function. These same variables change seasonally, and thus plant control on microbial community composition may be modulated or overshadowed by annual climatic patterns. We examined microbial community composition, C cycling processes, and environmental data in California annual grassland soils from beneath oak canopies and in open grassland areas to distinguish factors controlling microbial community composition and function seasonally and in association with the two plant overstory communities. Every 3 months for up to 2 years, we monitored microbial community composition using phospholipid fatty acid (PLFA) analysis, microbial biomass, respiration rates, microbial enzyme activities, and the activity of microbial groups using isotope labeling of PLFA biomarkers (13C-PLFA) . Distinct microbial communities were associated with oak canopy soils and open grassland soils and microbial communities displayed seasonal patterns from year to year. The effects of plant species and seasonal climate on microbial community composition were similar in magnitude. In this Mediterranean ecosystem, plant control of microbial community composition was primarily due to effects on soil water content, whereas the changes in microbial community composition seasonally appeared to be due, in large part, to soil temperature. Available soil carbon was not a significant control on microbial community composition. Microbial community composition (PLFA) and 13C-PLFA ordination values were strongly related to intra-annual variability in soil enzyme activities and soil respiration, but microbial biomass was not. In this Mediterranean climate, soil microclimate appeared to be the master variable controlling microbial community composition and function. ?? 2006 Springer Science+Business Media, Inc.

Role of an organic carbon-rich soil and Fe(III) reduction in reducing the toxicity and environmental mobility of chromium(VI) at a COPR disposal site.

PubMed

Ding, Weixuan; Stewart, Douglas I; Humphreys, Paul N; Rout, Simon P; Burke, Ian T

2016-01-15

Cr(VI) is an important contaminant found at sites where chromium ore processing residue (COPR) is deposited. No low cost treatment exists for Cr(VI) leaching from such sites. This study investigated the mechanism of interaction of alkaline Cr(VI)-containing leachate with an Fe(II)-containing organic matter rich soil beneath the waste. The soil currently contains 0.8% Cr, shown to be present as Cr(III)(OH)3 in EXAFS analysis. Lab tests confirmed that the reaction of Cr(VI) in site leachate with Fe(II) present in the soil was stoichiometrically correct for a reductive mechanism of Cr accumulation. However, the amount of Fe(II) present in the soil was insufficient to maintain long term Cr(VI) reduction at historic infiltration rates. The soil contains a population of bacteria dominated by a Mangroviflexus-like species, that is closely related to known fermentative bacteria, and a community capable of sustaining Fe(III) reduction in alkaline culture. It is therefore likely that in situ fermentative metabolism supported by organic matter in the soil produces more labile organic substrates (lactate was detected) that support microbial Fe(III) reduction. It is therefore suggested that addition of solid phase organic matter to soils adjacent to COPR may reduce the long term spread of Cr(VI) in the environment. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Geochemistry of soils from the San Rafael Valley, Santa Cruz County, Arizona

USGS Publications Warehouse

Folger, Helen W.; Gray, Floyd

2013-01-01

This study was conducted to determine whether surficial geochemical methods can be used to identify subsurface mineraldeposits covered by alluvium derived from surrounding areas. The geochemical investigation focused on an anomalous geo-physical magnetic high located in the San Rafael Valley in Santa Cruz County, Arizona. The magnetic high, inferred to be asso-ciated with a buried granite intrusion, occurs beneath Quaternary alluvial and terrace deposits. Soil samples were collected at a depth of 10 to 30 centimeters below land surface along transects that traverse the inferred granite. The samples were analyzed by inductively coupled plasma-mass spectrometry and by the partial-leach Mobile Metal Ion™ method. Principal component and factor analyses showed a strong correlation between the soils and source rocks hosting base-metal replacement deposits in the Harshaw and Patagonia Mining Districts. Factor analysis also indicated areas of high metal concentrations associated with the Meadow Valley Flat. Although no definitive geochemical signature was identified for the inferred granite, concentrations otungsten and iron in the surrounding area were slightly elevated.

Seal Formation Mechanism Beneath Animal Waste Holding Ponds

NASA Astrophysics Data System (ADS)

Cihan, A.; Tyner, J. S.; Wright, W. C.

2005-12-01

Infiltration of animal waste from holding ponds can cause contamination of groundwater. Typically, the initial flux from a pond decreases rapidly as a seal of animal waste particulates is deposited at the base of the pond. The purpose of this study was to investigate the mechanism of the seal formation. Twenty-four soil columns (10-cm diameter by 43-cm long) were hand-packed with sand, silty loam or clay soils. A 2.3 m column of dairy or swine waste was applied to the top of the each column. The leakage rate from each column was measured with respect to time to analyze the effect of seal formation on different soil textures and animal waste types. We tested our hypothesis that seal growth and the subsequent decrease of leachate production adheres to a filter cake growth model. Said model predicts that the cumulative leakage rate is proportional to the square root of time and to the square root of the height of the waste.

Activities report of the Department of Engineering

NASA Astrophysics Data System (ADS)

Acoustics, aerodynamics, fluid mechanics, design, electrical, materials science, mechanical, control, robotics, soil mechanics, structural engineering, thermodynamics, and turbomachine engineering research are described.

Enhancement of surfactant efficacy during the cleanup of engine oil contaminated soil using salt and multi-walled carbon nanotubes.

PubMed

Bonal, Niteesh Singh; Paramkusam, Bala Ramudu; Basudhar, Prabir Kumar

2018-06-05

The study aims to enhance the efficacy of surfactants using salt and multi-walled carbon nanotubes (MWCNT) for washing used engine oil (UEO) contaminated soil and compare the geotechnical properties of contaminated soil before and after washing (batch washing and soil washing). From batch washing of the contaminated soil the efficacy of the cleaning process is established. Contamination of soil with hydrocarbons present in UEO significantly affects its' engineering properties manifesting in no plasticity and low specific gravity; the corresponding optimum moisture content value is 6.42% while maximum dry density is 1.770 g/cc, which are considerably lower than those of the uncontaminated soil. The result also showed decrease in the values of cohesion intercept and increase in the friction angle values. The adopted soil washing technique resulted increase in specific gravity from 1.85 to 2.13 and cohesion from 0.443 to 1.04 kg/cm 2 and substantial decrease in the friction angle from 31.16° to 17.14° when washed with most efficient combination of SDS surfactant along with sodium meta-silicate (salt) and MWCNT. Effectiveness of the washing of contaminated soil by batch processing and soil washing techniques has been established qualitatively. The efficiency of surfactant treatment has been observed to be increased significantly by the addition of salt and MWCNT. Copyright © 2018 Elsevier B.V. All rights reserved.

Biting rates and developmental substrates for biting midges (Diptera: Ceratopogonidae) in Iquitos, Peru.

PubMed

Mercer, David R; Spinelli, Gustavo R; Watts, Douglas M; Tesh, Robert B

2003-11-01

Biting midges (Diptera: Ceratopogonidae) were collected at 16 periurban and rural sites around Iquitos, Peru, between 17 October 1996 and 26 May 1997. Culicoides paraensis (Goeldi), the principal vector of Oropouche virus, was the most commonly collected species (9,086 flies) with Culicoides insinuatus Wirth & Blanton second (7,229 flies). Although both species were collected at all sampling sites (linear (distance surveyed approximately 25 km), C. paraensis dominated at northern collection sites (> 90%), whereas C. insinuatus prevailed at southern collection sites (> 60%). C. paraensis were collected from human sentinels at a constant rate throughout daylight hours, at similar rates during wet and dry months, and regardless of rainfall. Larval developmental substrates for C. paraensis included decaying platano (Musa x paradisiaca L. [Musaceae]) stems, stumps, flowers, fruits, and debris beneath platano trees as well as from soil beneath a fruiting mamay (Syzygium malaccense Merr. & Perry [Myrtaceae] ) tree and organic-rich mud along a lake shoreline. C. insinuatus adults likewise emerged from decaying platano and organic-rich mud along a lake shoreline, but also from debris accumulated in the axils of aguaje (Mauritia flexuosa L. [Palmae]) fronds and decaying citrus fruit. Despite high numbers of biting adults near putative substrates, adults of neither species emerged from other decomposing plant material, soil, phytotelmata, or artificial containers. Because both species of biting midges emerged in high numbers from all parts of platano (ubiquitous in Iquitos), it will be challenging to control them through sanitation.

CO2 diffuse emission from maar lake: An example in Changbai volcanic field, NE China

NASA Astrophysics Data System (ADS)

Sun, Yutao; Guo, Zhengfu; Liu, Jiaqi; Du, Jianguo

2018-01-01

Numerous maars and monogenetic volcanic cones are distributed in northeast China, which are related to westward deep subduction of the Pacific Ocean lithosphere, comprising a significant part of the "Pacific Ring of Fire". It is well known that diffuse CO2 emissions from monogenetic volcanoes, including wet (e.g., maar lake) and dry degassing systems (e.g., soil diffuse emission, fault degassing, etc.), may contribute to budget of globally nature-derived greenhouse gases. However, their relationship between wet (e.g., maar lake) and concomitant dry degassing systems (e.g., soil diffuse emission, fault degassing, etc.) related to monogenetic volcanic field is poorly understood. Yuanchi maar, one of the typical monogenetic volcanic systems, is located on the eastern flank of Tianchi caldera in Changbai volcanic field of northeast China, which displays all of three forms of CO2 degassing including the maar lake, soil micro-seepage and fault degassing. Measurements of efflux of CO2 diffusion from the Yuanchi maar system (YMS) indicate that the average values of CO2 emissions from soil micro-seepage, fault degassing and water-air interface diffusion are 24.3 ± 23.3 g m- 2 d- 1, 39.2 ± 22.4 g m- 2 d- 1 and 2.4 ± 1.1 g m- 2 d- 1, respectively. The minimum output of CO2 diffuse emission from the YMS to the atmosphere is about 176.1 ± 88.3 ton/yr, of which 80.4% results from the dry degassing system. Degassing from the fault contributes to the most of CO2 emissions in all of the three forms of degassing in the YMS. Contributions of mantle, crust, air and organic CO2 to the soil gas are 0.01-0.10%, 10-20%, 32-36% and 48-54%, respectively, which are quantitatively constrained by a He-C isotope coupling calculation model. We propose that CO2 exsolves from the upper mantle melting beneath the Tianchi caldera, which migrates to the crustal magma chamber and further transports to the surface of YMS along the deep fault system. During the transportation processes, the emission of gas experiences crustal contamination, influence of magma chamber beneath the YMS, sub-surface processes and air dilution.

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

Adkins, Jaron; Jastrow, Julie D.; Morris, Geoffrey P.

Switchgrass (Panicum virgatum L), a cellulosic biofuel feedstock, may promote soil C 21 accumulation compared to annual cropping systems by increasing the amount and retention of 22 root-derived soil C inputs. The aim of this study was to assess how different switchgrass 23 cultivars impact soil C inputs and retention, whether these impacts vary with depth, and whether 24 specific root length (SRL) explains these impacts. We collected soil to a depth of 30 cm from six 25 switchgrass cultivars with root systems ranging from high to low SRL. The cultivars (C4 species) 26 were grown for 27 months onmore » soils previously dominated by C3 plants, allowing us to use the 27 natural difference in 13C isotopic signatures between C3 soils and C4 plants to quantify 28 switchgrass-derived C accumulation. The soil was fractionated into coarse particulate organic 29 matter (CPOM), fine particulate organic matter (FPOM), silt, and clay-sized fractions. We 30 measured total C and plant-derived C in all soil fractions across all depths. The study led to two main results: (1) bulk soil C concentrations beneath switchgrass cultivars varied by 40% in the 0-32 10 cm soil depth and by 70% in the 10-20 cm soil depth, and cultivars with high bulk soil C 33 concentrations tended to have relatively high C concentrations in the mineral soil fractions and 34 relatively low C concentrations in the POM fractions; (2) there were significant differences in 35 switchgrass-derived soil C between cultivars at the 0-10 cm depth, where soil C inputs ranged 36 from 1.2 to 3.2 mg C g-1 dry soil. There was also evidence of a positive correlation between SRL 37 and switchgrass-derived C inputs when one outlier data point was removed. These results 38 indicate that switchgrass cultivars differentially impact mechanisms contributing to soil C accumulation.« less

Enzyme leaching of surficial geochemical samples for detecting hydromorphic trace-element anomalies associated with precious-metal mineralized bedrock buried beneath glacial overburden in northern Minnesota

USGS Publications Warehouse

Clark, Robert J.; Meier, A.L.; Riddle, G.; ,

1990-01-01

One objective of the International Falls and Roseau, Minnesota, CUSMAP projects was to develop a means of conducting regional-scale geochemical surveys in areas where bedrock is buried beneath complex glacially derived overburden. Partial analysis of B-horizon soils offered hope for detecting subtle hydromorphic trace-element dispersion patterns. An enzyme-based partial leach selectively removes metals from oxide coatings on the surfaces of soil materials without attacking their matrix. Most trace-element concentrations in the resulting solutions are in the part-per-trillion to low part-per-billion range, necessitating determinations by inductively coupled plasma/mass spectrometry. The resulting data show greater contrasts for many trace elements than with other techniques tested. Spatially, many trace metal anomalies are locally discontinuous, but anomalous trends within larger areas are apparent. In many instances, the source for an anomaly seems to be either basal till or bedrock. Ground water flow is probably the most important mechanism for transporting metals toward the surface, although ionic diffusion, electrochemical gradients, and capillary action may play a role in anomaly dispersal. Sample sites near the Rainy Lake-Seine River fault zone, a regional shear zone, often have anomalous concentrations of a variety of metals, commonly including Zn and/or one or more metals which substitute for Zn in sphalerite (Cd, Ge, Ga, and Sn). Shifts in background concentrations of Bi, Sb, and As show a trend across the area indicating a possible regional zoning of lode-Au mineralization. Soil anomalies of Ag, Co, and Tl parallel basement structures, suggesting areas that may have potential for Cobalt/Thunder Baytype silver viens. An area around Baudette, Minnesota, which is underlain by quartz-chlorite-carbonate-altered shear zones, is anomalous in Ag, As, Bi, Co, Mo, Te, Tl, and W. Anomalies of Ag, As, Bi, Te, and W tend to follow the fault zones, suggesting potential for lode-Au deposits. Soil anomalies of Co, Mo, and Tl appear to follow northwest-striking structures that cross the shear zones, suggesting that Thunder Bay-type mineralization may have overprinted earlier mineralization along the shear zones.

CUTS FOR MTR EXCAVATION ILLUSTRATE SEDIMENTARY MANTLE OF SOIL AND ...

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

CUTS FOR MTR EXCAVATION ILLUSTRATE SEDIMENTARY MANTLE OF SOIL AND GRAVEL OVERLAYING LAVA ROCK FIFTY FEET BELOW. SAGEBRUSH HAS BEEN SCOURED FROM REST OF SITE. CAMERA PROBABLY FACES SOUTHWEST. INL NEGATIVE NO. 67. Unknown Photographer, 6/4/1950 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

Assessment of the mechanical properties of sisal fiber-reinforced silty clay using triaxial shear tests.

PubMed

Wu, Yankai; Li, Yanbin; Niu, Bin

2014-01-01

Fiber reinforcement is widely used in construction engineering to improve the mechanical properties of soil because it increases the soil's strength and improves the soil's mechanical properties. However, the mechanical properties of fiber-reinforced soils remain controversial. The present study investigated the mechanical properties of silty clay reinforced with discrete, randomly distributed sisal fibers using triaxial shear tests. The sisal fibers were cut to different lengths, randomly mixed with silty clay in varying percentages, and compacted to the maximum dry density at the optimum moisture content. The results indicate that with a fiber length of 10 mm and content of 1.0%, sisal fiber-reinforced silty clay is 20% stronger than nonreinforced silty clay. The fiber-reinforced silty clay exhibited crack fracture and surface shear fracture failure modes, implying that sisal fiber is a good earth reinforcement material with potential applications in civil engineering, dam foundation, roadbed engineering, and ground treatment.

An introduction to wave propagation in pavements and soils : theory and practice

DOT National Transportation Integrated Search

1999-02-01

This paper introduces the physics and analyst of wave propagation in pavement and soils. The study of wave propagation in soils can yield useful results to engineers concerned with resilient characteristics of a particular site, dynamic soils structu...

Soil microbial communities buffer physiological responses to drought stress in three hardwood species.

PubMed

Kannenberg, Steven A; Phillips, Richard P

2017-03-01

Trees possess myriad adaptations for coping with drought stress, but the extent to which their drought responses are influenced by interactions with soil microbes is poorly understood. To explore the role of microbes in mediating tree responses to drought stress, we exposed saplings of three species (Acer saccharum, Liriodendron tulipifera, and Quercus alba) to a four week experimental drought in mesocosms. Half of the pots were inoculated with a live soil slurry (i.e., a microbial inoculum derived from soils beneath the canopies of mature A. saccharum, L. tulipifera or Q. alba stands), while the other half of the pots received a sterile soil slurry. Soil microbes ameliorated drought stress in L. tulipifera by minimizing reductions in leaf water potential and by reducing photosynthetic declines. In A. saccharum, soil microbes reduced drought stress by lessening declines in leaf water potential, though these changes did not buffer the trees from declining photosynthetic rates. In Q. alba, soil microbes had no effects on leaf physiological parameters during drought stress. In all species, microbes had no significant effects on dynamic C allocation during drought stress, suggesting that microbial effects on plant physiology were unrelated to source-sink dynamics. Collectively, our results suggest that soil microbes have the potential to alter key parameters that are used to diagnose drought sensitivity (i.e., isohydry or anisohydry). To the extent that our results reflect dynamics occurring in forests, a revised perspective on plant hydraulic strategies that considers root-microbe interactions may lead to improved predictions of forest vulnerability to drought.

Large-Scale Wind-Tunnel Tests of Exhaust Ingestion Due to Thrust Reversal on a Four-Engine Jet Transport during Ground Roll

NASA Technical Reports Server (NTRS)

Tolhurst, William H., Jr.; Hickey, David H.; Aoyagi, Kiyoshi

1961-01-01

Wind-tunnel tests have been conducted on a large-scale model of a swept-wing jet transport type airplane to study the factors affecting exhaust gas ingestion into the engine inlets when thrust reversal is used during ground roll. The model was equipped with four small jet engines mounted in nacelles beneath the wing. The tests included studies of both cascade and target type reversers. The data obtained included the free-stream velocity at the occurrence of exhaust gas ingestion in the outboard engine and the increment of drag due to thrust reversal for various modifications of thrust reverser configuration. Motion picture films of smoke flow studies were also obtained to supplement the data. The results show that the free-stream velocity at which ingestion occurred in the outboard engines could be reduced considerably, by simple modifications to the reversers, without reducing the effective drag due to reversed thrust.

Transient Seepage for Levee Engineering Analyses

NASA Astrophysics Data System (ADS)

Tracy, F. T.

2017-12-01

Historically, steady-state seepage analyses have been a key tool for designing levees by practicing engineers. However, with the advances in computer modeling, transient seepage analysis has become a potentially viable tool. A complication is that the levees usually have partially saturated flow, and this is significantly more complicated in transient flow. This poster illustrates four elements of our research in partially saturated flow relating to the use of transient seepage for levee design: (1) a comparison of results from SEEP2D, SEEP/W, and SLIDE for a generic levee cross section common to the southeastern United States; (2) the results of a sensitivity study of varying saturated hydraulic conductivity, the volumetric water content function (as represented by van Genuchten), and volumetric compressibility; (3) a comparison of when soils do and do not exhibit hysteresis, and (4) a description of proper and improper use of transient seepage in levee design. The variables considered for the sensitivity and hysteresis studies are pore pressure beneath the confining layer at the toe, the flow rate through the levee system, and a levee saturation coefficient varying between 0 and 1. Getting results for SEEP2D, SEEP/W, and SLIDE to match proved more difficult than expected. After some effort, the results matched reasonably well. Differences in results were caused by various factors, including bugs, different finite element meshes, different numerical formulations of the system of nonlinear equations to be solved, and differences in convergence criteria. Varying volumetric compressibility affected the above test variables the most. The levee saturation coefficient was most affected by the use of hysteresis. The improper use of pore pressures from a transient finite element seepage solution imported into a slope stability computation was found to be the most grievous mistake in using transient seepage in the design of levees.

Phosphorus-mobilization ecosystem engineering: the roles of cluster roots and carboxylate exudation in young P-limited ecosystems

PubMed Central

Lambers, Hans; Bishop, John G.; Hopper, Stephen D.; Laliberté, Etienne; Zúñiga-Feest, Alejandra

2012-01-01

Background Carboxylate-releasing cluster roots of Proteaceae play a key role in acquiring phosphorus (P) from ancient nutrient-impoverished soils in Australia. However, cluster roots are also found in Proteaceae on young, P-rich soils in Chile where they allow P acquisition from soils that strongly sorb P. Scope Unlike Proteaceae in Australia that tend to proficiently remobilize P from senescent leaves, Chilean Proteaceae produce leaf litter rich in P. Consequently, they may act as ecosystem engineers, providing P for plants without specialized roots to access sorbed P. We propose a similar ecosystem-engineering role for species that release large amounts of carboxylates in other relatively young, strongly P-sorbing substrates, e.g. young acidic volcanic deposits and calcareous dunes. Many of these species also fix atmospheric nitrogen and release nutrient-rich litter, but their role as ecosystem engineers is commonly ascribed only to their diazotrophic nature. Conclusions We propose that the P-mobilizing capacity of Proteaceae on young soils, which contain an abundance of P, but where P is poorly available, in combination with inefficient nutrient remobilization from senescing leaves allows these species to function as ecosystem engineers. We suggest that diazotrophic species that colonize young soils with strong P-sorption potential should be considered for their positive effect on P availability, as well as their widely accepted role in nitrogen fixation. Their P-mobilizing activity possibly also enhances their nitrogen-fixing capacity. These diazotrophic species may therefore facilitate the establishment and growth of species with less-efficient P-uptake strategies on more-developed soils with low P availability through similar mechanisms. We argue that the significance of cluster roots and high carboxylate exudation in the development of young ecosystems is probably far more important than has been envisaged thus far. PMID:22700940

Phosphorus-mobilization ecosystem engineering: the roles of cluster roots and carboxylate exudation in young P-limited ecosystems.

PubMed

Lambers, Hans; Bishop, John G; Hopper, Stephen D; Laliberté, Etienne; Zúñiga-Feest, Alejandra

2012-07-01

Carboxylate-releasing cluster roots of Proteaceae play a key role in acquiring phosphorus (P) from ancient nutrient-impoverished soils in Australia. However, cluster roots are also found in Proteaceae on young, P-rich soils in Chile where they allow P acquisition from soils that strongly sorb P. Unlike Proteaceae in Australia that tend to proficiently remobilize P from senescent leaves, Chilean Proteaceae produce leaf litter rich in P. Consequently, they may act as ecosystem engineers, providing P for plants without specialized roots to access sorbed P. We propose a similar ecosystem-engineering role for species that release large amounts of carboxylates in other relatively young, strongly P-sorbing substrates, e.g. young acidic volcanic deposits and calcareous dunes. Many of these species also fix atmospheric nitrogen and release nutrient-rich litter, but their role as ecosystem engineers is commonly ascribed only to their diazotrophic nature. We propose that the P-mobilizing capacity of Proteaceae on young soils, which contain an abundance of P, but where P is poorly available, in combination with inefficient nutrient remobilization from senescing leaves allows these species to function as ecosystem engineers. We suggest that diazotrophic species that colonize young soils with strong P-sorption potential should be considered for their positive effect on P availability, as well as their widely accepted role in nitrogen fixation. Their P-mobilizing activity possibly also enhances their nitrogen-fixing capacity. These diazotrophic species may therefore facilitate the establishment and growth of species with less-efficient P-uptake strategies on more-developed soils with low P availability through similar mechanisms. We argue that the significance of cluster roots and high carboxylate exudation in the development of young ecosystems is probably far more important than has been envisaged thus far.

Reading the Molecular Code in Soils

NASA Astrophysics Data System (ADS)

Hess, N. J.; Tfaily, M. M.; O'Brien, S. L.; Tolic, N.; Jastrow, J. D.; Amonette, J. E.

2015-12-01

There is much that we understand about the relationship between plants, microbes, soil, and water but that understanding is incomplete at the molecular scale. With advent of high throughput genomic sequencing we are beginning to appreciate the diversity of microbial community structure and function and its response to the rhythm of plant function. Through the lens of high-resolution mass spectrometry we are getting our first glimpses of the diversity of soil and pore water organic chemistry at the molecular level. In combination, these diverse data streams are revealing traces of chemical metabolic pathways. This approach promises to reveal many exciting future discoveries, shedding light into the "black box" that exists beneath our feet. In this talk we discuss our experience with the molecular characterization of soils from native prairie to restored prairie to active corn-soybean soils from the DOE funded CSiTE project in Batavia, Illinois. We focus on how common soil separation and fractionation techniques can affect the resulting molecular soil characterization by comparing whole soils to those that have been fractionated into micro- and macro-aggregates and their corresponding silt and clay fractions. When carefully utilized and interpreted these fractionation techniques can be utilized for deepening understanding of the biotic and abiotic chemical pathways effecting the organic chemistry in the different soil fractions. In highly fractionated soils we find significant differences in organic chemistry between silt and clay separates of corresponding hierarchical aggregate fractions. However the most biologically rich information resides in the whole soil. Here we see significant gradients in soil chemistry across to active agricultural to restored to native prairie soils. These results suggest a cautionary note, namely that soil fractionation prior to molecular characterization can reveal much about the "abiotic" interactions between organic molecules and soil minerals but the much of the "biotic" story resides in the whole soil.

Initial crop growth in soil collected from a closed animal waste lagoon.

PubMed

Zhu, L; Kirkham, M B

2003-03-01

In the 21st century, remediation of the soil beneath animal waste lagoons will become an important issue, as they are closed due to environmental regulations or to abandonment. The possibility of growing crops in the soil, which has high concentrations of ammonium-N, has not been studied. The objective of this experiment was to determine if crop species would germinate and grow in lagoon soil. Soil was gathered from a lagoon that had received wastes from swine (Sus scrofa) and beef (Bos taurus) since 1968. Eight crops were grown in greenhouse pots containing the lagoon soil: winter barley (Hordeum vulgare L. 'Weskan'); field corn (Zea mays L., Cargill's hybrid 7997); 'Plainsman' winter rapeseed [Brassica napus L. spp. oleifera (Metzg.) Sinsk. f. biennis]; soybean [Glycine max (L.) Merr. 'KS 4694'); forage sorghum [Sorghum bicolor (L.) Moench 'Norkan']; sunflower (Helianthus annuus L. 'Hysun 354'); and winter wheat (Triticum aestivum L.)--two cultivars: '2137' and 'Turkey.' Plants were grown for 35 days in lagoon soil or an agricultural soil (Haynie very fine sandy loam; coarse-silty, mixed, superactive, calcareous, mesic Mollic Udifluvent) obtained from a field near the closed lagoon. Ammonium-N (average value of 692 mg/kg) was about 70-85 times greater than the average value of 8-10 mg/kg NH4-N in Kansan soils. The lagoon soil was nonsodic and had a salinity ranking of "medium" with an electrical conductivity averaging 2.29 dS/m. The high ammonium-N concentration in the lagoon soil was not inhibitory to emergence and growth. The eight crops grew taller in the lagoon soil than in the agricultural soil. Except for '2137' wheat, dry weight was higher in the lagoon soil than in the agricultural soil. The results showed that the lagoon soil is not detrimental to early growth of eight crops.

Engineered passive bioreactive barriers: risk-managing the legacy of industrial soil and groundwater pollution.

PubMed

Kalin, Robert M

2004-06-01

Permeable reactive barriers are a technology that is one decade old, with most full-scale applications based on abiotic mechanisms. Though there is extensive literature on engineered bioreactors, natural biodegradation potential, and in situ remediation, it is only recently that engineered passive bioreactive barrier technology is being considered at the commercial scale to manage contaminated soil and groundwater risks. Recent full-scale studies are providing the scientific confidence in our understanding of coupled microbial (and genetic), hydrogeologic, and geochemical processes in this approach and have highlighted the need to further integrate engineering and science tools.

ON-SITE ENGINEERING REPORT OF THE SLURRY-PHASE BIOLOGICAL REACTOR FOR PILOT-SCALE TESTING ON CONTAMINATED SOIL

EPA Science Inventory

The performance of pilot-scale bioslurry treatment on creosote-contaminated soil was evaluated. Five reactors containing 66 L of slurry (30% soil by weight), were operated in parallel. The soil was a sandy soil with minor gravel content. The pilot-scale phase utilized an inoculum...

Control of Eucryptorrhynchus scrobiculatus (Coleoptera: Cuculionidae), a Major Pest of Ailanthus altissima (Sapindales: Simaroubaceae), Using a Modified Square Trap Net.

PubMed

Yang, Kailang; Wen, Xiaojian; Ren, Yuan; Wen, Junbao

2018-04-19

Eucryptorrhynchus scrobiculatus (Motschulsky) (Coleoptera: Cuculionidae) is a borer that mainly attacks the tree of heaven, Ailanthus altissima (Mill.) Swingle (Sapindales: Simaroubaceae), and is one of the most damaging forestry pests in China. We developed a trap net for entangling and immobilizing soil-emerging weevils in order to reduce their impact. Recapture rates of weevils in the laboratory was significantly higher with nylon netting of 9, 10, or 11 mm mesh sizes than larger sizes, and these sizes were used to make trial nets for preventing weevil emergence from the soil around impacted trees in the field. Nets were 2 × 2 m with a reinforced border and Velcro-closable, radial slit which allowed the net to be arranged around the base of the tree while producing an unbroken barrier beneath the soil surface (i.e., a modified square trap net, MSTN). Recapture rates of weevils released in the soil did not differ among the MSTNs of 9, 10, or 11 mm mesh sizes. MSTN treatments significantly reduced emergence by naturally-occurring weevils from the soil surrounding trees and reduced numbers of weevils caught in population monitoring traps deployed in treated stands. The results demonstrated that MSTNs might be used to manage of E. scrobiculatus.

Comparative analysis of bones, mites, soil chemistry, nematodes and soil micro-eukaryotes from a suspected homicide to estimate the post-mortem interval.

PubMed

Szelecz, Ildikó; Lösch, Sandra; Seppey, Christophe V W; Lara, Enrique; Singer, David; Sorge, Franziska; Tschui, Joelle; Perotti, M Alejandra; Mitchell, Edward A D

2018-01-08

Criminal investigations of suspected murder cases require estimating the post-mortem interval (PMI, or time after death) which is challenging for long PMIs. Here we present the case of human remains found in a Swiss forest. We have used a multidisciplinary approach involving the analysis of bones and soil samples collected beneath the remains of the head, upper and lower body and "control" samples taken a few meters away. We analysed soil chemical characteristics, mites and nematodes (by microscopy) and micro-eukaryotes (by Illumina high throughput sequencing). The PMI estimate on hair 14 C-data via bomb peak radiocarbon dating gave a time range of 1 to 3 years before the discovery of the remains. Cluster analyses for soil chemical constituents, nematodes, mites and micro-eukaryotes revealed two clusters 1) head and upper body and 2) lower body and controls. From mite evidence, we conclude that the body was probably brought to the site after death. However, chemical analyses, nematode community analyses and the analyses of micro-eukaryotes indicate that decomposition took place at least partly on site. This study illustrates the usefulness of combining several lines of evidence for the study of homicide cases to better calibrate PMI inference tools.

Natural and anthropogenic radioactivity levels and the associated radiation hazard in the soil of Oodalia Tea Estate in the hilly region of Fatickchari in Chittagong, Bangladesh

PubMed Central

Absar, Nurul; Rahman, M. Mashiur; Kamal, Masud; Siddique, Naziba; Chowdhury, Mantazul Islam

2014-01-01

Radioactivity in the soil of a tea garden in the Fatickchari area in Chittagong, Bangladesh, was measured using a high-resolution HPGe detector. The soil samples were collected from depths of up to 20 cm beneath the soil surface. The activity concentrations of naturally occurring 238U and 232Th were observed to be in the range of 27 ± 7 to 53 ± 8 Bq kg−1 and 36 ± 11 to 72 ± 11 Bq kg−1, respectively. The activity concentration of 40K ranged from 201 ± 78 to 672 ± 81 Bq kg−1, and the highest activity of fallout 137Cs observed was 10 ± 1 Bq kg−1. The average activity concentration observed for 238U was 39 ± 8 Bq kg−1, for 232Th was 57 ± 11 Bq kg−1, for 40K was 384 ± 79 Bq kg−1 and for 137Cs was 5 ± 0.5 Bq kg−1. The radiological hazard parameters (representative level index, radium equivalent activity, outdoor and indoor dose rates, outdoor and indoor annual effective dose equivalents, and radiation hazard index) were calculated from the radioactivity in the soil. PMID:25078001

Reducing variation in decomposition odour profiling using comprehensive two-dimensional gas chromatography.

PubMed

Perrault, Katelynn A; Stefanuto, Pierre-Hugues; Stuart, Barbara H; Rai, Tapan; Focant, Jean-François; Forbes, Shari L

2015-01-01

Challenges in decomposition odour profiling have led to variation in the documented odour profile by different research groups worldwide. Background subtraction and use of controls are important considerations given the variation introduced by decomposition studies conducted in different geographical environments. The collection of volatile organic compounds (VOCs) from soil beneath decomposing remains is challenging due to the high levels of inherent soil VOCs, further confounded by the use of highly sensitive instrumentation. This study presents a method that provides suitable chromatographic resolution for profiling decomposition odour in soil by comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry using appropriate controls and field blanks. Logarithmic transformation and t-testing of compounds permitted the generation of a compound list of decomposition VOCs in soil. Principal component analysis demonstrated the improved discrimination between experimental and control soil, verifying the value of the data handling method. Data handling procedures have not been well documented in this field and standardisation would thereby reduce misidentification of VOCs present in the surrounding environment as decomposition byproducts. Uniformity of data handling and instrumental procedures will reduce analytical variation, increasing confidence in the future when investigating the effect of taphonomic variables on the decomposition VOC profile. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Embedded Empiricisms in Soft Soil Technology

NASA Astrophysics Data System (ADS)

Wijeyesekera, D. C.; John, L. M. S. Alvin; Adnan, Z.

2016-07-01

Civil engineers of today are continuously challenged by innovative projects that push further the knowledge boundaries with conceptual and/or ingenious solutions leading to the realization of that once was considered impossible in the realms of geotechnology. Some of the forward developments rely on empirical methods embedded within soft soil technology and the spectral realms of engineering in its entirety. Empiricisms unlike folklore are not always shrouded in mysticism but can find scientific reasoning to justify them being adopted in design and tangible construction projects. This lecture therefore is an outline exposition of how empiricism has been integrally embedded in total empirical beginnings in the evolution of soft soil technology from the Renaissance time, through the developments of soil mechanics in the 19th century which in turn has paved the way to the rise of computational soil mechanics. Developments in computational soil mechanics has always embraced and are founded on a wide backdrop of empirical geoenvironment simulations. However, it is imperative that a competent geotechnical engineer needs postgraduate training combined with empiricism that is based on years of well- winnowed practical experience to fathom the diverseness and complexity of nature. However, experience being regarded more highly than expertise can, perhaps inadvertently, inhibit development and innovation.

Three-dimensional geologic modeling to determine the spatial attributes of hydrocarbon contamination, Noval Facility Fuel Farm, El Centro, California

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

Johnson, C.; Mutch, S.; Padgett, D.

An investigation was conducted at the Naval Air Facility located in El Centro (NAFEC), to determine the vertical and horizontal extent of hydrocarbon contamination at the facilities fuel farm. The fuel products are the result of tank and pipeline leakage, past tank cleaning, and past disposal of fuel dispensing and filter cleaning practices. Subsurface soil and groundwater data was collected via soil borings, monitoring wells, and CPT probes. Soil, groundwater, and analytical data were integrated using the LYNX geoscience modeling system (GMS). Interactive sessions with the data visualizer helped guide the modeling and identify data gaps. Modeling results indicate amore » continuous surface confining clay layer to a depth of about 12 to 15 ft. Groundwater is confined beneath this clay layer and monitoring wells indicate about 3 to 5 ft of artesian head. Hydrocarbon contamination is concentrated within this clay layer from about 5 to 12 ft below the ground surface. Residual fuel products located in the groundwater are attributed to slow leakage through the confirming clay layer. LYNX was also used to compute volumes of contaminated soil to aid in remediation cost analysis. Preliminary figures indicate about 60,000 yards[sup 3] of contaminated soil. Since the contamination is primarily confined to relatively impermeable clayey soils, site remediation will likely be ex-situ land farming.« less

Sensitivity of mesquite shrubland CO2 exchange to precipitation in contrasting landscape settings.

PubMed

Potts, Daniel L; Scott, Russell L; Cable, Jessica M; Huxman, Travis E; Williams, David G

2008-10-01

In semiarid ecosystems, physiography (landscape setting) may interact with woody-plant and soil microbe communities to constrain seasonal exchanges of material and energy at the ecosystem scale. In an upland and riparian shrubland, we examined the seasonally dynamic linkage between ecosystem CO2 exchange, woody-plant water status and photosynthesis, and soil respiration responses to summer rainfall. At each site, we compared tower-based measurements of net ecosystem CO2 exchange (NEE) with ecophysiological measurements among velvet mesquite (Prosopis velutina Woot.) in three size classes and soil respiration in sub-canopy and inter-canopy micro-sites. Monsoonal rainfall influenced a greater shift in the magnitude of ecosystem CO2 assimilation in the upland shrubland than in the riparian shrubland. Mesquite water status and photosynthetic gas exchange were closely linked to the onset of the North American monsoon in the upland shrubland. In contrast, the presence of shallow alluvial groundwater in the riparian shrubland caused larger size classes of mesquite to be physiologically insensitive to monsoonal rains. In both shrublands, soil respiration was greatest beneath mesquite canopies and was coupled to shallow soil moisture abundance. Physiography, through its constraint on the physiological sensitivity of deeply rooted woody plants, may interact with plant-mediated rates of soil respiration to affect the sensitivity of semiarid-ecosystem carbon exchange in response to episodic rainfall.

[Effects of Cultivation Soil Properties on the Transport of Genetically Engineered Microorganism in Huabei Plain].

PubMed

Zhang, Jing; Liu, Ping; Liu, Chun; Chen, Xiao-xuan; Zhang, Lei

2015-12-01

The transport of genetically engineered microorganism (GEM) in the soil is considered to be the important factor influencing the enhanced bioremediation of polluted soil. The transport of an atrazine-degrading GEM and its influencing factors were investigated in the saturated cultivation soil of Huabei Plain. The results showed that horizontal infiltration was the main mechanism of GEM transport in the saturated cultivation soil. The transport process could be simulated using the filtration model. Soil properties showed significant effects on pore water flow and GEM transport in saturated soil. When particle size, porosity and sand component of the soil increased, the hydraulic conductivity constant increased and filtration coefficient of GEM decreased in saturated soil, indicating the reduced retention of GEM in the soil. An increase in infiltration flow also increased hydraulic conductivity constant in saturated soil and consequently decreased filtration coefficient of GEM. When hydraulic conductivity constants ranged from 5.02 m · d⁻¹ to 6.70 m · d⁻¹ in the saturated soil, the filtration coefficients of GEM varied from 0.105 to 0.274. There was a significantly negative correlation between them.

Gravity-driven transport of three engineered nanomaterials in unsaturated soils and their effects on soil pH and nutrient release.

PubMed

Conway, Jon R; Keller, Arturo A

2016-07-01

The gravity-driven transport of TiO2, CeO2, and Cu(OH)2 engineered nanomaterials (ENMs) and their effects on soil pH and nutrient release were measured in three unsaturated soils. ENM transport was found to be highly limited in natural soils collected from farmland and grasslands, with the majority of particles being retained in the upper 0-3 cm of the soil profile, while greater transport depth was seen in a commercial potting soil. Physical straining appeared to be the primary mechanism of retention in natural soils as ENMs immediately formed micron-scale aggregates, which was exacerbated by coating particles with Suwannee River natural organic matter (NOM) which promote steric hindrance. Small changes in soil pH were observed in natural soils contaminated with ENMs that were largely independent of ENM type and concentration, but differed from controls. These changes may have been due to enhanced release of naturally present pH-altering ions (Mg(2+), H(+)) in the soil via substitution processes. These results suggest ENMs introduced into soil will likely be highly retained near the source zone. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modeling of U-series Radionuclide Transport Through Soil at Pena Blanca, Chihuahua, Mexico

NASA Astrophysics Data System (ADS)

Pekar, K. E.; Goodell, P. C.; Walton, J. C.; Anthony, E. Y.; Ren, M.

2007-05-01

The Nopal I uranium deposit is located at Pena Blanca in Chihuahua, Mexico. Mining of high-grade uranium ore occurred in the early 1980s, with the ore stockpiled nearby. The stockpile was mostly cleared in the 1990s; however, some of the high-grade boulders have remained there, creating localized sources of radioactivity for a period of 25-30 years. This provides a unique opportunity to study radionuclide transport, because the study area did not have any uranium contamination predating the stockpile in the 1980s. One high-grade boulder was selected for study based upon its shape, location, and high activity. The presumed drip-line off of the boulder was marked, samples from the boulder surface were taken, and then the boulder was moved several feet away. Soil samples were taken from directly beneath the boulder, around the drip-line, and down slope. Eight of these samples were collected in a vertical profile directly beneath the boulder. Visible flakes of boulder material were removed from the surficial soil samples, because they would have higher concentrations of U-series radionuclides and cause the activities in the soil samples to be excessively high. The vertical sampling profile used 2-inch thicknesses for each sample. The soil samples were packaged into thin plastic containers to minimize the attenuation and to standardize sample geometry, and then they were analyzed by gamma-ray spectroscopy with a Ge(Li) detector for Th-234, Pa-234, U-234, Th-230, Ra-226, Pb-214, Bi-214, and Pb-210. The raw counts were corrected for self-attenuation and normalized using BL-5, a uranium standard from Beaverlodge, Saskatchewan. BL-5 allowed the counts obtained on the Ge(Li) to be referenced to a known concentration or activity, which was then applied to the soil unknowns for a reliable calculation of their concentrations. Gamma ray spectra of five soil samples from the vertical profile exhibit decreasing activities with increasing depth for the selected radionuclides. Independent multi-element analyses of three samples by ICP-MS show decreasing uranium concentration with depth as well. The transport of the radionuclides is evaluated using STANMOD, a Windows-based software package for evaluating solute transport in porous media using analytical solutions of the advection-dispersion solute transport equation. The package allows various one-dimensional, advection-dispersion parameters to be determined by fitting mathematical solutions of theoretical transport models to observed data. The results are promising for future work on the release rate of radionuclides from the boulder, the dominant mode of transport (e.g., particulate or dissolution), and the movement of radionuclides through porous media. The measured subsurface transport rates provide modelers with a model validation dataset.

Methodological approach for evaluating the response of soil hydrological behavior to irrigation with treated municipal wastewater

NASA Astrophysics Data System (ADS)

Coppola, A.; Santini, A.; Botti, P.; Vacca, S.; Comegna, V.; Severino, G.

2004-06-01

This paper aims mainly to provide experimental evidence of the consequences of urban wastewater reuse in irrigation practices on the hydrological behavior of soils. The effects on both the hydraulic and dispersive properties of representative soils in southern Sardinia are illustrated. Ten undisturbed soil monoliths, 120 cm in height and 40 cm in diameter, were collected from plots previously selected through a soil survey. Soil hydraulic and solute transport properties were determined before and after application of wastewater using transient water infiltration and steady state-solute transport column experiments. Detailed spatial-temporal information on the propagation of water and solute through the soil profiles were obtained by monitoring soil water contents, θ, pressure heads, h, and solute concentrations, C, measured by a network of time domain reflectometry probes, tensiometers and solution samplers horizontally inserted in each column at different depths. A disturbed layer at the soil surface, which expands in depth with time, was observed, characterized by reduced soil porosity, translation of pore size distribution towards narrower pores and consequent decrease in water retention, hydraulic conductivity and hydrodynamic dispersion. It is shown that these changes occurring in the disturbed soil layer, although local by nature, affect the hydrological behavior of the whole soil profile. Due to the disturbed layer formation, the soil beneath never saturates. Such behavior has important consequences on the solute transport in soils, as unsaturated conditions mean higher residence times of solutes, even of those normally characterized by considerable mobility (e.g. boron), which may accumulate along the profile. The results mainly provide experimental evidence that knowledge of the chemical and microbiological composition of the water is not sufficient to evaluate its suitability for irrigation. Other factors, mainly soil physical and hydrological characteristics, should be considered in order to define appropriate guidelines for wastewater management.

Extraction of soil solution by drainage centrifugation-effects of centrifugal force and time of centrifugation on soil moisture recovery and solute concentration in soil moisture of loess subsoils.

PubMed

Fraters, Dico; Boom, Gerard J F L; Boumans, Leo J M; de Weerd, Henk; Wolters, Monique

2017-02-01

The solute concentration in the subsoil beneath the root zone is an important parameter for leaching assessment. Drainage centrifugation is considered a simple and straightforward method of determining soil solution chemistry. Although several studies have been carried out to determine whether this method is robust, hardly any results are available for loess subsoils. To study the effect of centrifugation conditions on soil moisture recovery and solute concentration, we sampled the subsoil (1.5-3.0 m depth) at commercial farms in the loess region of the Netherlands. The effect of time (20, 35, 60, 120 and 240 min) on recovery was studied at two levels of the relative centrifugal force (733 and 6597g). The effect of force on recovery was studied by centrifugation for 35 min at 117, 264, 733, 2932, 6597 and 14,191g. All soil moisture samples were chemically analysed. This study shows that drainage centrifugation offers a robust, reproducible and standardised way for determining solute concentrations in mobile soil moisture in silt loam subsoils. The centrifugal force, rather than centrifugation time, has a major effect on recovery. The maximum recovery for silt loams at field capacity is about 40%. Concentrations of most solutes are fairly constant with an increasing recovery, as most solutes, including nitrate, did not show a change in concentration with an increasing recovery.

Phoenix Mars Lander Spacecraft Heat Shield Installation

NASA Image and Video Library

2007-05-11

In the Payload Hazardous Servicing Facility, the Phoenix Mars Lander spacecraft undergoes spin testing. The Phoenix mission is the first project in NASA's first openly competed program of Mars Scout missions. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. It will serve as NASA's first exploration of a potential modern habitat on Mars and open the door to a renewed search for carbon-bearing compounds, last attempted with NASA's Viking missions in the 1970s. A stereo color camera and a weather station will study the surrounding environment while the other instruments check excavated soil samples for water, organic chemicals and conditions that could indicate whether the site was ever hospitable to life. Microscopes can reveal features as small as one one-thousandth the width of a human hair. Launch of Phoenix aboard a Delta II rocket is targeted for Aug. 3 from Cape Canaveral Air Force Station in Florida.

Phoenix Mars Lander Spacecraft Processing

NASA Image and Video Library

2007-05-10

This closeup shows the spin test of the Phoenix Mars Lander in the Payload Hazardous Servicing Facility. The Phoenix mission is the first project in NASA's first openly competed program of Mars Scout missions. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. It will serve as NASA's first exploration of a potential modern habitat on Mars and open the door to a renewed search for carbon-bearing compounds, last attempted with NASA’s Viking missions in the 1970s. A stereo color camera and a weather station will study the surrounding environment while the other instruments check excavated soil samples for water, organic chemicals and conditions that could indicate whether the site was ever hospitable to life. Microscopes can reveal features as small as one one-thousandth the width of a human hair. Launch of Phoenix aboard a Delta II rocket is targeted for Aug. 3 from Cape Canaveral Air Force Station in Florida.

Phoenix Mars Lander Spacecraft Heat Shield Installation

NASA Image and Video Library

2007-05-11

In the Payload Hazardous Servicing Facility, technicians install the heat shield on the Phoenix Mars Lander spacecraft. The Phoenix mission is the first project in NASA's first openly competed program of Mars Scout missions. Phoenix will land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and any associated rocks, while monitoring polar climate. Landing is planned in May 2008 on arctic ground where a mission currently in orbit, Mars Odyssey, has detected high concentrations of ice just beneath the top layer of soil. It will serve as NASA's first exploration of a potential modern habitat on Mars and open the door to a renewed search for carbon-bearing compounds, last attempted with NASA's Viking missions in the 1970s. A stereo color camera and a weather station will study the surrounding environment while the other instruments check excavated soil samples for water, organic chemicals and conditions that could indicate whether the site was ever hospitable to life. Microscopes can reveal features as small as one one-thousandth the width of a human hair. Launch of Phoenix aboard a Delta II rocket is targeted for Aug. 3 from Cape Canaveral Air Force Station in Florida.

Geophysical Methods for Monitoring Soil Stabilization Processes

EPA Science Inventory

Soil stabilization involves methods used to turn unconsolidated and unstable soil into a stiffer, consolidated medium that could support engineered structures, alter permeability, change subsurface flow, or immobilize contamination through mineral precipitation. Among the variety...

Water Repellent Soils: The use of electrical resistivity tomography in a small scale catchment model to evaluate the effectiveness of surfactants.

NASA Astrophysics Data System (ADS)

Lowe, Mary-Anne; Mathes, Falko; McGrath, Gavan; Leopold, Matthias

2017-04-01

Soil water repellence effects large areas of land in Western Australia causing large forfeits in agricultural profit. Surfactants are a potential management tool, however, in field trials they have had varied success and their impact on water movement is poorly understood. This study employs a novel approach to determine the effectiveness of surfactants at modifying infiltration into water repellent soils. Using a physical catchment model (0.6 m × 0.6 m) with soils arranged in a ridge and furrow topography, irrigation and runoff were quantified. Electrical resistivity tomography (ERT) was used to measure changes in soil moisture patterns in two dimensions. Two sandy soils with contrasting severity of water repellence, as measured by the Molarity of Ethanol Droplet (MED) test, were assessed. The impact of two surfactants, at an equivalent rate of 1 L ha-1, and an untreated control were monitored over 5 wetting events. With surfactant application the very severely water repellent soil (MED 4.2 M) showed an increase in infiltration of up to 31%, which was concentrated under the area of surfactant application in the furrow. Volumetric water contents beneath the furrow increased up to 40% below 20 mm depth. Water infiltration into the untreated soil with low water repellence (MED 1.0 M) was 98%, and this did not significantly change with surfactant application. This physical catchment model, combined with hydrological and geophysical monitoring provides a useful tool to assess the effectiveness of surfactants in increasing water infiltration and subsurface soil moisture in water repellent soils. The work is part of the Australian CRC for Polymer project.

Light-toned salty soils and co-existing Si-rich species discovered by the Mars Exploration Rover Spirit in Columbia Hills

USGS Publications Warehouse

Wang, Alian; Bell, J.F.; Li, Ron; Johnson, J. R.; Farrand, W. H.; Cloutis, E.A.; Arvidson, R. E.; Crumpler, L.; Squyres, S. W.; McLennan, S.M.; Herkenhoff, K. E.; Ruff, S.W.; Knudson, A.T.; Chen, Wei; Greenberger, R.

2008-01-01

Light-toned soils were exposed, through serendipitous excavations by Spirit Rover wheels, at eight locations in the Columbia Hills. Their occurrences were grouped into four types on the basis of geomorphic settings. At three major exposures, the light-toned soils are hydrous and sulfate-rich. The spatial distributions of distinct types of salty soils vary substantially: with centimeter-scaled heterogeneities at Paso Robles, Dead Sea, Shredded, and Champagne-Penny, a well-mixed nature for light-toned soils occurring near and at the summit of Husband Hill, and relatively homogeneous distributions in the two layers at the Tyrone site. Aeolian, fumarolic, and hydrothermal fluid processes are suggested to be responsible for the deposition, transportation, and accumulation of these light-toned soils. In addition, a change in Pancam spectra of Tyrone yellowish soils was observed after being exposed to current Martian surface conditions for 175 sols. This change is interpreted to be caused by the dehydration of ferric sulfates on the basis of laboratory simulations and suggests a relative humidity gradient beneath the surface. Si-rich nodules and soils were observed near the major exposures of S-rich soils. They possess a characteristic feature in Pancam visible near-infrared (Vis-NIR) spectra that may be diagnostic of hydrated species, and this spectral feature can be used to search for additional Si-rich species. The exposures of hydrated salty soils within various geomorphic settings imply the potential existence of hydrous minerals in similar settings over a much wider area. Hydrous sulfates represent one of the candidates that may contribute the high level of water equivalent hydrogen in equatorial regions detected by the Neutron Spectrometer on Mars Odyssey.

Soil nitrogen accretion along a floodplain terrace chronosequence in northwest Alaska: Influence of the nitrogen-fixing shrub Shepherdia canadensis

USGS Publications Warehouse

Rhoades, Charles; Binkley, Dan; Oskarsson, Hlynur; Stottlemyer, Robert

2008-01-01

Nitrogen enters terrestrial ecosystems through multiple pathways during primary succession. We measured accumulation of total soil nitrogen and changes in inorganic nitrogen (N) pools across a 300-y sequence of river terraces in northwest Alaska and assessed the contribution of the nitrogen-fixing shrub Shepherdia canadensis. Our work compared 5 stages of floodplain succession, progressing from a sparsely vegetated silt cap to dense shrubby vegetation, balsam poplar-dominated (Populus balsamifera) and white spruce-dominated (Picea glauca) mixed forests, and old-growth white spruce forest. Total soil N (0–30 cm depth) increased throughout the age sequence, initially by 2.4 g N·m−2·y−1 during the first 120 y of terrace development, then by 1.6 g N·m−2·y−1 during the subsequent 2 centuries. Labile soil N, measured by anaerobic incubation, increased most rapidly during the first 85 y of terrace formation, then remained relatively constant during further terrace development. On recently formed terraces, Shepherdia shrubs enriched soil N pools several-fold compared to soil beneath Salix spp. shrubs or intercanopy sites. Total and labile soil N accretion was proportional to Shepherdia cover during the first century of terrace development, and mineral soil δ15N content indicated that newly formed river terraces receive substantial N through N-fixation. About half the 600 g total N·m−2 accumulated across the river terrace chronosequence occurred during the 120 y when S. canadensis was dominant. Sediment deposited by periodic flooding continued to add N to terrace soils after the decline in Shepherdia abundance and may have contributed 25% of the total N found in the floodplain terrace soils.

Depth profiling of Pu, 241Am and 137Cs in soils from southern Belarus measured by ICP-MS and alpha and gamma spectrometry.

PubMed

Boulyga, Sergei F; Zoriy, Myroslav; Ketterer, Michael E; Becker, J Sabine

2003-08-01

The depth distribution of plutonium, americium, and 137Cs originating from the 1986 accident at the Chernobyl Nuclear Power Plant (NPP) was investigated in several soil profiles in the vicinity from Belarus. The vertical migration of transuranic elements in soils typical of the 30 km relocation area around Chernobyl NPP was studied using inductively coupled plasma mass spectrometry (ICP-MS), alpha spectrometry, and gamma spectrometry. Transuranic concentrations in upper soil layers ranged from 6 x 10(-12) g g(-1) to 6 x 10(-10) g g(-1) for plutonium and from 1.8 x 10(-13) g g(-1) to 1.6 x 10(-11) g g(-1) for americium. These concentrations correspond to specific activities of (239+240)Pu of 24-2400 Bq kg(-1) and specific activity of 241Am of 23-2000 Bq kg(-1), respectively. Transuranics in turf-podzol soil migrate slowly to the deeper soil layers, thus, 80-95%, of radionuclide inventories were present in the 0-3 cm intervals of turf-podzol soils collected in 1994. In peat-marsh soil migration processes occur more rapidly than in turf-podzol and the maximum concentrations are found beneath the soil surface (down to 3-6 cm). The depth distributions of Pu and Am are essentially identical for a given soil profile. (239+240)Pu/137Cs and 241Am/137Cs activity ratios vary by up to a factor of 5 at some sites while smaller variations in these ratios were observed at a site close to Chernobyl, suggesting that 137Cs is dominantly particle associated close to Chernobyl but volatile species of 137Cs are of relatively greater importance at the distant sites.

Preservation of a Preglacial Landscape Under the Center of the Greenland Ice Sheet

NASA Technical Reports Server (NTRS)

Bierman, Paul R.; Corbett, Lee B.; Graly, Joseph A.; Neumann, Thomas Allen; Lini, Andrea; Crosby, Benjamin T.; Rood, Dylan H.

2014-01-01

Continental ice sheets typically sculpt landscapes via erosion; under certain conditions, ancient landscapes can be preserved beneath ice and can survive extensive and repeated glaciation. We used concentrations of atmospherically produced cosmogenic beryllium-10, carbon, and nitrogen to show that ancient soil has been preserved in basal ice for millions of years at the center of the ice sheet at Summit, Greenland. This finding suggests ice sheet stability through the Pleistocene (i.e., the past 2.7 million years). The preservation of this soil implies that the ice has been non-erosive and frozen to the bed for much of that time, that there was no substantial exposure of central Greenland once the ice sheet became fully established, and that preglacial landscapes can remain preserved for long periods under continental ice sheets

Evolution of black carbon properties in soil

USDA-ARS?s Scientific Manuscript database

Black carbon deposited in soil from natural or deliberate wildfires and engineered black carbon products (biochar) intentionally added to soil are known to have significant effects on soil biogeochemical processes and in many cases to influence the yield and quality of crops and to enhance the abili...

Soil nitrogen availability in the open steppe with Stipa tenacissima

NASA Astrophysics Data System (ADS)

Novosadova, Irena; Damian Ruiz Sinoga, Jose; Záhora, Jaroslav

2010-05-01

Open steppes dominated by Stipa tenacissima L. constitute one of the most representative ecosystems of the semi-arid zones of Iberian Peninsula and show a higher degree of variability in composition and structure (Maestre et al., 2007). Vegetation patchiness, which are seen as mosaics including vegetated and non-vegetated components, is a common feature of such open steppes (Valentin et al., 1999). Ecosystem functioning is strongly related to the spatial pattern of grass tussocks. Soils beneath S. tenacissima grass show higher fertility and improved microclimatic conditions, favouring the formation of "resource islands" (Maestre et al., 2007). First, soil moisture is greater beneath the clumps, due to water harvesting through rainfall interception, uptake by roots from adjacent unvegetated areas and water redistribution from gaps to clumps (Bergkamp et al., 1999; Puigdefá bregas et al., 1999). Second, the canopy diminishes the intense solar radiation (Maestre et al., 2001) avoiding the sun-baking effect, which is an important factor for soil temperature change and physical disruption (Magid et al., 1999). Plant clumps either functioned as microbial hotspots where enhanced microbially driven ecosystem processes took place or as microbial banks capable of undergoing a burst of activity under favourable climatic conditions (Goberna et al., 2007). The competition for water and resources between plants and microorganisms is strong and mediated trough an enormous variety of exudates and resource depletion intended to regulate soil microbial communities in the rhizosphere, control herbivory, encourage beneficial symbioses, and change chemical and physical properties in soil (Pugnaire et Armas, 2008). On the other hand there exists experimental evidence of a non-patchy distribution of certain soil microbial properties in semi-arid Mediterranean patchy ecosystems (Goberna et al., 2007). The microbial nutrient release processes have a fundamental role in ecosystem functioning, particularly in Mediterranean areas, where nutrient availability, mainly nitrogen and phosphorous, represents a limiting factor (Sardans et al., 2005) together with water availability. Soil N availability has been found to affect plant water use efficiency (Sardans et al., 2008a). This strong link between N availability and water use efficiency makes particularly important the understanding of factors affecting soil N availability in Mediterranean ecosystems in view of the future predicted increasing drought in this area. Changes in the soil nitrogen availability in the open steppe with S. tenacissima were monitored over a two distinct period of time during the years 2008 and 2009 at a field site in semi-arid south-eastern Spain (Novosádová et al., 2010). The availability of ammonia-nitrogen and nitrate nitrogen was estimated in situ according to Binkley at Matson (1982) by the trapping of mineral N into the ion exchange resin inserted into special cover. The availability of soil ammonia-N as well as the availability of nitrate-N were in the 2008 year significantly influenced by the addition of different substrate (only 38% of control after the cellulose addition and 176% of control after the raw silk addition). In the following 2009 year was the N availability probably due to favorable soil moisture nearly the same in all experimental variants. The availability of ammonia-N was, in general, higher than the availability of nitrate-N, but the differences were less noticeable in 2008 year. It can be concluded, that the microbial competition for available nitrogen is very high and spatially and/or temporary significantly different.

Method of draining water through a solid waste site without leaching

DOEpatents

Treat, Russell L.; Gee, Glendon W.; Whyatt, Greg A.

1993-01-01

The present invention is a method of preventing water from leaching solid waste sites by preventing atmospheric precipitation from contacting waste as the water flows through a solid waste site. The method comprises placing at least one drain hole through the solid waste site. The drain hole is seated to prevent waste material from entering the drain hole, and the solid waste site cover material is layered and graded to direct water to flow toward the drain hole and to soil beneath the waste site.

Horizontal Advanced Tensiometer

DOEpatents

Hubbell, Joel M.; Sisson, James B.

2004-06-22

An horizontal advanced tensiometer is described that allows the monitoring of the water pressure of soil positions, particularly beneath objects or materials that inhibit the use of previous monitoring wells. The tensiometer includes a porous cup, a pressure transducer (with an attached gasket device), an adaptive chamber, at least one outer guide tube which allows access to the desired horizontal position, a transducer wire, a data logger and preferably an inner guide tube and a specialized joint which provides pressure on the inner guide tube to maintain the seal between the gasket of the transducer and the adaptive chamber.

Method of draining water through a solid waste site without leaching

DOEpatents

Treat, R.L.; Gee, G.W.; Whyatt, G.A.

1993-02-02

The present invention is a method of preventing water from leaching solid waste sites by preventing atmospheric precipitation from contacting waste as the water flows through a solid waste site. The method comprises placing at least one drain hole through the solid waste site. The drain hole is seated to prevent waste material from entering the drain hole, and the solid waste site cover material is layered and graded to direct water to flow toward the drain hole and to soil beneath the waste site.

24 CFR 3285.4 - Incorporation by reference (IBR).

Code of Federal Regulations, 2010 CFR

2010-04-01

... purchase from the Structural Engineering Institute/American Society of Civil Engineers (SEI/ASCE), 1801... for Engineering Purposes (Unified Soil Classification System), 2000, IBR approved for the table at...

Multi-scale observations of the variability of magmatic CO2 emissions, Mammoth Mountain, CA, USA

NASA Astrophysics Data System (ADS)

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

2014-09-01

One of the primary indicators of volcanic unrest at Mammoth Mountain is diffuse emission of magmatic CO2, which can effectively track this unrest if its variability in space and time and relationship to near-surface meteorological and hydrologic phenomena versus those occurring at depth beneath the mountain are understood. In June-October 2013, we conducted accumulation chamber soil CO2 flux surveys and made half-hourly CO2 flux measurements with automated eddy covariance and accumulation chamber (auto-chamber) instrumentation at the largest area of diffuse CO2 degassing on Mammoth Mountain (Horseshoe Lake tree kill; HLTK). Estimated CO2 emission rates for HLTK based on 20 June, 30 July, and 24-25 October soil CO2 flux surveys were 165, 172, and 231 t d- 1, respectively. The average (June-October) CO2 emission rate estimated for this area was 123 t d- 1 based on an inversion of 4527 eddy covariance CO2 flux measurements and corresponding modeled source weight functions. Average daily eddy covariance and auto-chamber CO2 fluxes consistently declined over the four-month observation time. Wavelet analysis of auto-chamber CO2 flux and environmental parameter time series was used to evaluate the periodicity of, and local correlation between these variables in time-frequency space. Overall, CO2 emissions at HLTK were highly dynamic, displaying short-term (hourly to weekly) temporal variability related to meteorological and hydrologic changes, as well as long-term (monthly to multi-year) variations related to migration of CO2-rich magmatic fluids beneath the volcano. Accumulation chamber soil CO2 flux surveys were also conducted in the four additional areas of diffuse CO2 degassing on Mammoth Mountain in July-August 2013. Summing CO2 emission rates for all five areas yielded a total for the mountain of 311 t d- 1, which may suggest that emissions returned to 1998-2009 levels, following an increase from 2009 to 2011.

Effects of moisture and grain size on the mechanisms of rainsplash transport

NASA Astrophysics Data System (ADS)

Taube, S. R.; Furbish, D. J.

2010-12-01

Desert shrubs accumulate soil mounds beneath their canopies through rainsplash transport. Previous studies of this process have suggested that there is a preferential concentration of smaller grain sizes closer to the base of the shrub, based on the idea that smaller material is more readily splashed inward beneath the shrub. However, our studies have shown that there are two mechanisms of ejection of the grains with moist soil conditions, each preferentially moving either large or small grain sizes. Larger grains tend to be launched from grain-to-grain collisions following drop impact and travel as individual grains. Smaller grains appear to clump together and move as a single large "grain". The medium-sized grains generally had a greater travel distance than the very large or very small grains, potentially because they involve both modes of transport with a greater effective transfer of energy from the raindrop to the grains. The average travel distance is greatest near 100 microns, which is reflected by the data of Leguedois, et al. (2005). Experiments using high-speed imaging reveals that there is a marked difference between the mechanism of transport when the sediment grains are dry versus when they are moist. The dry grains are rapidly deposited about the impact site with a small proportion moving far from the site. However, moist grains tend to clump together to form “blobs” of water and sediment. Immediately after impact, the drop creates a water corona with entrained sediment, which then contracts into water-sediment blobs that are rocketed outwards from the impact, leaving little to no grain mass near the impact site. Varying degrees of moisture content appeared to have little influence on grain dispersal, leading us to believe that once the soil material is moist (but not saturated), its splash behavior is mostly related to details of the drop corona.

Multi-scale observations of the variability of magmatic CO2 emissions, Mammoth Mountain, CA, USA

USGS Publications Warehouse

Lewicki, Jennifer L.; Hilley, George E.

2014-01-01

One of the primary indicators of volcanic unrest at Mammoth Mountain is diffuse emission of magmatic CO2, which can effectively track this unrest if its variability in space and time and relationship to near-surface meteorological and hydrologic phenomena versus those occurring at depth beneath the mountain are understood. In June–October 2013, we conducted accumulation chamber soil CO2 flux surveys and made half-hourly CO2 flux measurements with automated eddy covariance and accumulation chamber (auto-chamber) instrumentation at the largest area of diffuse CO2 degassing on Mammoth Mountain (Horseshoe Lake tree kill; HLTK). Estimated CO2 emission rates for HLTK based on 20 June, 30 July, and 24–25 October soil CO2 flux surveys were 165, 172, and 231 t d− 1, respectively. The average (June–October) CO2 emission rate estimated for this area was 123 t d− 1 based on an inversion of 4527 eddy covariance CO2 flux measurements and corresponding modeled source weight functions. Average daily eddy covariance and auto-chamber CO2 fluxes consistently declined over the four-month observation time. Wavelet analysis of auto-chamber CO2 flux and environmental parameter time series was used to evaluate the periodicity of, and local correlation between these variables in time–frequency space. Overall, CO2 emissions at HLTK were highly dynamic, displaying short-term (hourly to weekly) temporal variability related to meteorological and hydrologic changes, as well as long-term (monthly to multi-year) variations related to migration of CO2-rich magmatic fluids beneath the volcano. Accumulation chamber soil CO2 flux surveys were also conducted in the four additional areas of diffuse CO2 degassing on Mammoth Mountain in July–August 2013. Summing CO2 emission rates for all five areas yielded a total for the mountain of 311 t d− 1, which may suggest that emissions returned to 1998–2009 levels, following an increase from 2009 to 2011.

Experimental datasets on engineering properties of expansive soil treated with common salt.

PubMed

Durotoye, Taiwo O; Akinmusuru, Joseph O; Ogundipe, Kunle E

2018-06-01

Construction of highway pavements or high rise structures over the expansive soils are always problematic due to failures of volume change or swelling characteristic experienced in the water permeability of the soil. The data in this article represented summary of (Durotoye et al., 2016; Durotoye, 2016) [1], [2]. The data explored different percentages of sodium chloride as additive in stabilizing the engineering properties of expansive soil compared with other available stabilizer previously worked on. Experimental procedures carried out on expansive soil include: (Liquid limit, Plastic limit, Plasticity index, Shrinkage limit, Specific gravity Free swell index and Optimum water content) to determine the swelling parameters and (maximum dry density, California bearing ratio and unconfined compressive strength) to determine the strength parameters. The results of the experiment were presented in pie charts.

Do soil organisms affect aboveground litter decomposition in the semiarid Patagonian steppe, Argentina?

PubMed

Araujo, Patricia I; Yahdjian, Laura; Austin, Amy T

2012-01-01

Surface litter decomposition in arid and semiarid ecosystems is often faster than predicted by climatic parameters such as annual precipitation or evapotranspiration, or based on standard indices of litter quality such as lignin or nitrogen concentrations. Abiotic photodegradation has been demonstrated to be an important factor controlling aboveground litter decomposition in aridland ecosystems, but soil fauna, particularly macrofauna such as termites and ants, have also been identified as key players affecting litter mass loss in warm deserts. Our objective was to quantify the importance of soil organisms on surface litter decomposition in the Patagonian steppe in the absence of photodegradative effects, to establish the relative importance of soil organisms on rates of mass loss and nitrogen release. We estimated the relative contribution of soil fauna and microbes to litter decomposition of a dominant grass using litterboxes with variable mesh sizes that excluded groups of soil fauna based on size class (10, 2, and 0.01 mm), which were placed beneath shrub canopies. We also employed chemical repellents (naphthalene and fungicide). The exclusion of macro- and mesofauna had no effect on litter mass loss over 3 years (P = 0.36), as litter decomposition was similar in all soil fauna exclusions and naphthalene-treated litter. In contrast, reduction of fungal activity significantly inhibited litter decomposition (P < 0.001). Although soil fauna have been mentioned as a key control of litter decomposition in warm deserts, biogeographic legacies and temperature limitation may constrain the importance of these organisms in temperate aridlands, particularly in the southern hemisphere.

Challenges in Bulk Soil Sampling and Analysis for Vapor Intrusion Screening of Soil

EPA Science Inventory

This draft Engineering Issue Paper discusses technical issues with monitoring soil excavations for VOCs and describes options for such monitoring as part of a VI pathway assessment at sites where soil excavation is being considered or used as part of the remedy for VOC-contaminat...

Numerical modeling of consolidation processes in hydraulically deposited soils

NASA Astrophysics Data System (ADS)

Brink, Nicholas Robert

Hydraulically deposited soils are encountered in many common engineering applications including mine tailing and geotextile tube fills, though the consolidation process for such soils is highly nonlinear and requires the use of advanced numerical techniques to provide accurate predictions. Several commercially available finite element codes poses the ability to model soil consolidation, and it was the goal of this research to assess the ability of two of these codes, ABAQUS and PLAXIS, to model the large-strain, two-dimensional consolidation processes which occur in hydraulically deposited soils. A series of one- and two-dimensionally drained rectangular models were first created to assess the limitations of ABAQUS and PLAXIS when modeling consolidation of highly compressible soils. Then, geotextile tube and TSF models were created to represent actual scenarios which might be encountered in engineering practice. Several limitations were discovered, including the existence of a minimum preconsolidation stress below which numerical solutions become unstable.

Electrical Grounding - a Field for Geophysicists and Electrical Engineers Partnership

NASA Astrophysics Data System (ADS)

Freire, P. F.; Pane, E.; Guaraldo, N.

2012-12-01

Technology for designing ground electrodes for high-voltage direct current transmission systems (HVDC) has being using in the last years, deep soil models based on a wide range of geophysical methods. These models shall include detailed representation of shallow soil, down to 100 meters, in order to allow the evaluation of the soil conditions where the ground electrodes will be buried. Also deep soil models are needed, to be used for the interference studies, which shall represent a soil volume of about 15 km deep and a surface area of about 15 to 30 km radius. Large facilities for power plants (hydroelectric and wind farms, for example) and industrial complexes (such as petrochemical plants) has become usual at the current stage of Brazil industrialization. Grounding mats for these facilities are made of a buried cooper mesh, interconnected to a wide variety of metallic masses, such as steel reinforced concrete foundations, ducts in general etc. These grounding systems may present dimensions with the order of hundreds of meters, and, at least in Brazil, are usually calculated by using electrical resistivity soil models, based on short spacing Wenner measurements (with maximum spacing of about 64 m.). The soil model shall be the best possible representation of the environment in which the grounding electrodes are immersed, for the purpose of calculation of resistance or for digital simulation. The model to be obtained is limited by the amount and quality of soil resistivity measurements are available, and the resources to be used in the calculations and simulations. Geophysics uses a wide range of technologies for exploring subsoil, ranging from surface measurements to wells logging - seismic, gravimetric, magnetic, electrical, electromagnetic and radiometric. The electrical and electromagnetic methods includes various measurement techniques (Wenner, Schlumberger, TDEM, Magneto-telluric etc.), which together allow the development of complex resistivity soil models, layered stratified or showing lateral variations, ranging down to several tens of kilometers deep, reaching the crust-mantle interface (typically with the order of 30-40 km). This work aims to analyze the constraints of the current soil models being used for grounding electrodes design, and suggests the need of a soil modeling methodology compatible with large grounding systems. Concerning the aspects related to soil modeling, electrical engineers need to get aware of geophysics resources, such as: - geophysical techniques for soil electrical resistivity prospection (down to about 15 kilometers deep); and - techniques for converting field measured data, from many different geophysical techniques, into adequate soil models for grounding grid simulation. It is also important to equalize the basic knowledge for the professionals that are working together for the specific purpose of soil modeling for electrical grounding studies. The authors have experienced the situation of electrical engineers working with geophysicists, but it was not clear for the latter the effective need of the electrical engineers, and for the engineers it was unknown the available geophysical resources, and also, what to do convert the large amount of soil resistivity data into a reliable soil model.

Phylogenetic and Functional Diversity of Total (DNA) and Expressed (RNA) Bacterial Communities in Urban Green Infrastructure Bioswale Soils.

PubMed

Gill, Aman S; Lee, Angela; McGuire, Krista L

2017-08-15

New York City (NYC) is pioneering green infrastructure with the use of bioswales and other engineered soil-based habitats to provide stormwater infiltration and other ecosystem functions. In addition to avoiding the environmental and financial costs of expanding traditional built infrastructure, green infrastructure is thought to generate cobenefits in the form of diverse ecological processes performed by its plant and microbial communities. Yet, although plant communities in these habitats are closely managed, we lack basic knowledge about how engineered ecosystems impact the distribution and functioning of soil bacteria. We sequenced amplicons of the 16S ribosomal subunit, as well as seven genes associated with functional pathways, generated from both total (DNA-based) and expressed (RNA) soil communities in the Bronx, NYC, NY, in order to test whether bioswale soils host characteristic bacterial communities with evidence for enriched microbial functioning, compared to nonengineered soils in park lawns and tree pits. Bioswales had distinct, phylogenetically diverse bacterial communities, including taxa associated with nutrient cycling and metabolism of hydrocarbons and other pollutants. Bioswale soils also had a significantly greater diversity of genes involved in several functional pathways, including carbon fixation ( cbbL-R [ cbbL gene, red-like subunit] and apsA ), nitrogen cycling ( noxZ and amoA ), and contaminant degradation ( bphA ); conversely, no functional genes were significantly more abundant in nonengineered soils. These results provide preliminary evidence that urban land management can shape the diversity and activity of soil communities, with positive consequences for genetic resources underlying valuable ecological functions, including biogeochemical cycling and degradation of common urban pollutants. IMPORTANCE Management of urban soil biodiversity by favoring taxa associated with decontamination or other microbial metabolic processes is a powerful prospect, but it first requires an understanding of how engineered soil habitats shape patterns of microbial diversity. This research adds to our understanding of urban microbial biogeography by providing data on soil bacteria in bioswales, which had relatively diverse and compositionally distinct communities compared to park and tree pit soils. Bioswales also contained comparatively diverse pools of genes related to carbon sequestration, nitrogen cycling, and contaminant degradation, suggesting that engineered soils may serve as effective reservoirs of functional microbial biodiversity. We also examined both total (DNA-based) and expressed (RNA) communities, revealing that total bacterial communities (the exclusive targets in the vast majority of soil studies) were poor predictors of expressed community diversity, pointing to the value of quantifying RNA, especially when ecological functioning is considered. Copyright © 2017 American Society for Microbiology.

Phylogenetic and Functional Diversity of Total (DNA) and Expressed (RNA) Bacterial Communities in Urban Green Infrastructure Bioswale Soils

PubMed Central

Lee, Angela; McGuire, Krista L.

2017-01-01

ABSTRACT New York City (NYC) is pioneering green infrastructure with the use of bioswales and other engineered soil-based habitats to provide stormwater infiltration and other ecosystem functions. In addition to avoiding the environmental and financial costs of expanding traditional built infrastructure, green infrastructure is thought to generate cobenefits in the form of diverse ecological processes performed by its plant and microbial communities. Yet, although plant communities in these habitats are closely managed, we lack basic knowledge about how engineered ecosystems impact the distribution and functioning of soil bacteria. We sequenced amplicons of the 16S ribosomal subunit, as well as seven genes associated with functional pathways, generated from both total (DNA-based) and expressed (RNA) soil communities in the Bronx, NYC, NY, in order to test whether bioswale soils host characteristic bacterial communities with evidence for enriched microbial functioning, compared to nonengineered soils in park lawns and tree pits. Bioswales had distinct, phylogenetically diverse bacterial communities, including taxa associated with nutrient cycling and metabolism of hydrocarbons and other pollutants. Bioswale soils also had a significantly greater diversity of genes involved in several functional pathways, including carbon fixation (cbbL-R [cbbL gene, red-like subunit] and apsA), nitrogen cycling (noxZ and amoA), and contaminant degradation (bphA); conversely, no functional genes were significantly more abundant in nonengineered soils. These results provide preliminary evidence that urban land management can shape the diversity and activity of soil communities, with positive consequences for genetic resources underlying valuable ecological functions, including biogeochemical cycling and degradation of common urban pollutants. IMPORTANCE Management of urban soil biodiversity by favoring taxa associated with decontamination or other microbial metabolic processes is a powerful prospect, but it first requires an understanding of how engineered soil habitats shape patterns of microbial diversity. This research adds to our understanding of urban microbial biogeography by providing data on soil bacteria in bioswales, which had relatively diverse and compositionally distinct communities compared to park and tree pit soils. Bioswales also contained comparatively diverse pools of genes related to carbon sequestration, nitrogen cycling, and contaminant degradation, suggesting that engineered soils may serve as effective reservoirs of functional microbial biodiversity. We also examined both total (DNA-based) and expressed (RNA) communities, revealing that total bacterial communities (the exclusive targets in the vast majority of soil studies) were poor predictors of expressed community diversity, pointing to the value of quantifying RNA, especially when ecological functioning is considered. PMID:28576763

Engineering Manual for McMurdo Station. Revision

DTIC Science & Technology

1979-01-01

1-3 Rock Quarry .. ..... ....... ....... ..... 1-4 . Fast Ice .. ..... ....... ....... ........ 1-4 Snow-Drift Ice Slabs. .. ....... ....... ...... 1...Chapter 6. Fast p.- The Fortress Rocks, about 3,000 feet ice was found beneath the sewage outfall north of the central McMurdo Station structure in DF-71...concrete aggregate tion from the land (Figure 1-11). Drilling has and fill material in the McMurdo area. This also shown the presence of fast ice on the

Properties of the Loess Sediments in Ostrava Region (Czech Republic) and Comparison with Some Other Loess Sediments

PubMed Central

Marschalko, Marian; Yilmaz, Işık; Fojtova, Lucie; Lamich, David; Bednarik, Martin

2013-01-01

This study deals with a methodical identification and evaluation of physical-mechanical properties of one genetic type of geological structure. This is represented by an engineering-geological zone of eolian sediments, which is regionally rather abundant. The paper contributes to a need to identify typical soil properties for widespread geological environments in a particular region and thus add to good engineering geologists and geotechnical engineers' awareness in the region. Such information is much required as it permits comparing results of newly conducted engineering-geological investigations and research with the results characteristic for the region in question. It is vital for engineering geologists and geotechnical engineers to be sufficiently informed on the foundation soil properties of widespread geological environments because of professionalism and higher quality of their work results. Comparing other loess sediment studies worldwide it was discovered that the physical properties of the most abundant clays of low to medium plasticity, sandy clays, and sands as foundation soils vary as for the plasticity index, porosity, natural water content, and bulk density to a certain extent but not as significantly as once expected. PMID:24391464

PLUG STORAGE BUILDING, TRA611, AWAITS SHIELDING SOIL TO BE PLACED ...

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

PLUG STORAGE BUILDING, TRA-611, AWAITS SHIELDING SOIL TO BE PLACED OVER PLUG STORAGE TUBES. WING WALLS WILL SUPPORT EARTH FILL. MTR, PROCESS WATER BUILDING, AND WORKING RESERVOIR IN VIEW BEYOND PLUG STORAGE. CAMERA FACES NORTHEAST. INL NEGATIVE NO. 2949. Unknown Photographer, 7/30/1951 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

Can the invasive earthworm, Amynthas agrestis, be controlled with prescribed fire?

Treesearch

Hiroshi Ikeda; Mac A. Callaham Jr.; Joseph J. O' Brien; Benjamin S. Hornsby; Evelyn S. Wenk

2015-01-01

Biological invasions are one of the most significant global-scale problems caused by human activities. Earthworms function as ecosystem engineers in soil ecosystems because their feeding and burrowing activities fundamentally change the physical and biological characteristics of the soils they inhabit. As a result of this “engineering,” earthworm invasions can have...

Corrosion Monitoring Research of New York City Bridges : TechBrief

DOT National Transportation Integrated Search

2013-12-01

Understanding unsaturated expansive soil has always been a major challenge for soil scientists and engineers. Due to presence of high quantity of montmorillonite mineral in the Moreland clay in northern Louisiana, structural damage due to soil heave/...

Structure and earthworms

USDA-ARS?s Scientific Manuscript database

Earthworms are an important part of the soil ecosystem and an indicator of soil quality. Sometimes referred to as ecosystem engineers, they play a pivotal role in maintaining soil productivity. Their burrowing, feeding, and casting activities alter the physical, chemical, and biological properties o...

Assessment of existing roadside swales with engineered filter soil: II. Treatment efficiency and in situ mobilization in soil columns.

PubMed

Ingvertsen, Simon T; Cederkvist, Karin; Jensen, Marina B; Magid, Jakob

2012-01-01

Use of roadside infiltration systems using engineered filter soil for optimized treatment has been common practice in Germany for decades, but little documentation is available regarding their long-term treatment performance. Here we present the results of laboratory leaching experiments with intact soil columns (15 cm i.d., 25-30 cm length) collected from two German roadside infiltration swales constructed in 1997. The columns were irrigated with synthetic solutions of unpolluted or polluted (dissolved heavy metals and fine suspended solids) road runoff, as well as a soluble nonreactive tracer (bromide) and a dye (brilliant blue). The experiments were performed at two irrigation rates corresponding to catchment rainfall intensities of approximately 5.1 and 34 mm/h. The bromide curves indicated that preferential flow was more pronounced at high irrigation rates, which was supported by the flow patterns revealed in the dye tracing experiment. Nonetheless, the soils seemed to be capable of retaining most of the dissolved heavy metals from the polluted road runoff at both low and high irrigation rates, except for Cr, which appears to pass through the soil as chromate. Fluorescent microspheres (diameter = 5 μm) used as surrogates for fine suspended solids were efficiently retained by the soils (>99%). However, despite promising treatment abilities, internal mobilization of heavy metals and P from the soil was observed, resulting in potentially critical effluent concentrations of Cu, Zn, and Pb. This is mainly ascribed to high concentrations of in situ mobilized dissolved organic carbon (DOC). Suggestions are provided for possible improvements and further research to minimize DOC mobilization in engineered filter soils. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Pit bearing capacity effect on status of soil plug during pile driving in ocean engineering

NASA Astrophysics Data System (ADS)

Yan, Shu-Wang; Zhou, Qun-Hua; Liu, Run; Dong, Wei

2011-06-01

Foundation piles of the offshore oil platforms in the Bohai Bay are usually longer than 100 m with a diameter larger than 2 m. Driving such long and large-sized piles into the ground is a difficult task. It needs a comprehensive consider ation of the pile dimensions, soil properties and the hammer energy. Thoughtful drivability analysis has to be performed in the design stage. It has been shown that judging whether the soil column inside the pile is fully plugged, which makes the pile behave as close-ended, strongly influences the accuracy of drivability analysis. Engineering practice repeatedly indicates that the current methods widely used for soil plug judgment often give incorrect results, leading the designers to make a wrong decision. It has been found that this problem is caused by the ignorance of the bearing capacity provided by the soil surrounding the pile. Based on the Terzaghi's bearing capacity calculation method for deep foundation, a new approach for judging soil plug status is put forward, in which the surcharge effect has been considered and the dynamic effect coefficient is included. This approach has been applied to some practical engineering projects successfully, which may give more reasonable results than the currently used method does.

Closing the Knowledge Gap: Effects of Land Use Conversion on Belowground Carbon near the 100th Meridian

NASA Astrophysics Data System (ADS)

Waldron, S. E.; Phillips, R. L.; Dell, R.; Suddick, E. C.

2012-12-01

Native prairie of the northern Great Plains near the 100th meridian is currently under land use conversion pressure due to high commodity prices. From 2002 to 2007, approximately 303,515 hectares of prairie were converted to crop production in the Prairie Pothole Region (PPR) from Montana to the Dakotas. The spatiotemporal effects of land-use conversion on soil organic matter are still unclear for the PPR. Effects will vary with management, soil properties and time, making regional experiments and simulation modeling necessary. Grassland conservationists are interested in soil carbon data and soil carbon simulation models to inform potential voluntary carbon credit programs. These programs require quantification of changes in soil carbon associated with land-use conversion and management. We addressed this issue by 1) designing a regional-scale experiment, 2) collecting and analyzing soil data, and 3) interviewing producers about land management practices, as required for regional, process-based biogeochemical models. We selected farms at random within a 29,000 km2 area of interest and measured soil properties at multiple depths for native prairie and adjacent annual crop fields. The cores were processed at six different depths (between 0 and 100 cm) for bulk density, pH, texture, total carbon, inorganic carbon, and total nitrogen. We found that the largest difference in soil organic carbon occurred at the 0-10 cm depth, but the magnitude of the effect of land use varied with soil properties and land management. Results from this project, coupled with regional model simulations (Denitrification-Decomposition, DNDC) represent the baseline data needed for future voluntary carbon credit programs and long-term carbon monitoring networks. Enrollment in such programs could help ranchers and farmers realize a new income stream from maintaining their native prairie and the carbon stored beneath it.

Assessment of the Mechanical Properties of Sisal Fiber-Reinforced Silty Clay Using Triaxial Shear Tests

PubMed Central

Wu, Yankai; Li, Yanbin; Niu, Bin

2014-01-01

Fiber reinforcement is widely used in construction engineering to improve the mechanical properties of soil because it increases the soil's strength and improves the soil's mechanical properties. However, the mechanical properties of fiber-reinforced soils remain controversial. The present study investigated the mechanical properties of silty clay reinforced with discrete, randomly distributed sisal fibers using triaxial shear tests. The sisal fibers were cut to different lengths, randomly mixed with silty clay in varying percentages, and compacted to the maximum dry density at the optimum moisture content. The results indicate that with a fiber length of 10 mm and content of 1.0%, sisal fiber-reinforced silty clay is 20% stronger than nonreinforced silty clay. The fiber-reinforced silty clay exhibited crack fracture and surface shear fracture failure modes, implying that sisal fiber is a good earth reinforcement material with potential applications in civil engineering, dam foundation, roadbed engineering, and ground treatment. PMID:24982951

Interim Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Alaska Region

DTIC Science & Technology

2006-02-01

insoluble but ferrous iron easily enters the soil solution and is moved or translocated to other areas of the soil. Areas that have lost iron...causing oxidation of ferrous iron present in the soil solution . They are evidence of saturated and reduced soil conditions during the plant’s

An Example Emphasizing Mass-Volume Relationships for Problem Solving in Soils

ERIC Educational Resources Information Center

Heitman, J. L.; Vepraskas, M. J.

2009-01-01

Mass-volume relationships are a useful tool emphasized for problem solving in many geo-science and engineering applications. These relationships also have useful applications in soil science. Developing soils students' ability to utilize mass-volume relationships through schematic diagrams of soil phases (i.e., air, water, and solid) can help to…

Predicting Nitrate Transport under Future Climate Scenarios beneath the Nebraska Management Systems Evaluation Area (MSEA) site

NASA Astrophysics Data System (ADS)

Li, Y.; Akbariyeh, S.; Gomez Peña, C. A.; Bartlet-Hunt, S.

2017-12-01

Understanding the impacts of future climate change on soil hydrological processes and solute transport is crucial to develop appropriate strategies to minimize adverse impacts of agricultural activities on groundwater quality. The goal of this work is to evaluate the direct effects of climate change on the fate and transport of nitrate beneath a center-pivot irrigated corn field in Nebraska Management Systems Evaluation Area (MSEA) site. Future groundwater recharge rate and actual evapotranspiration rate were predicted based on an inverse modeling approach using climate data generated by Weather Research and Forecasting (WRF) model under the RCP 8.5 scenario, which was downscaled from global CCSM4 model to a resolution of 24 by 24 km2. A groundwater flow model was first calibrated based on historical groundwater table measurement and was then applied to predict future groundwater table in the period 2057-2060. Finally, predicted future groundwater recharge rate, actual evapotranspiration rate, and groundwater level, together with future precipitation data from WRF, were used in a three-dimensional (3D) model, which was validated based on rich historic data set collected from 1993-1996, to predict nitrate concentration in soil and groundwater from the year 2057 to 2060. Future groundwater recharge was found to be decreasing in the study area compared to average groundwater recharge data from the literature. Correspondingly, groundwater elevation was predicted to decrease (1 to 2 ft) over the five years of simulation. Predicted higher transpiration data from climate model resulted in lower infiltration of nitrate concentration in subsurface within the root zone.

Predicting Nitrate Transport under Future Climate Scenarios beneath the Nebraska Management Systems Evaluation Area (MSEA) site

NASA Astrophysics Data System (ADS)

Li, Y.; Akbariyeh, S.; Gomez Peña, C. A.; Bartlet-Hunt, S.

2016-12-01

Understanding the impacts of future climate change on soil hydrological processes and solute transport is crucial to develop appropriate strategies to minimize adverse impacts of agricultural activities on groundwater quality. The goal of this work is to evaluate the direct effects of climate change on the fate and transport of nitrate beneath a center-pivot irrigated corn field in Nebraska Management Systems Evaluation Area (MSEA) site. Future groundwater recharge rate and actual evapotranspiration rate were predicted based on an inverse modeling approach using climate data generated by Weather Research and Forecasting (WRF) model under the RCP 8.5 scenario, which was downscaled from global CCSM4 model to a resolution of 24 by 24 km2. A groundwater flow model was first calibrated based on historical groundwater table measurement and was then applied to predict future groundwater table in the period 2057-2060. Finally, predicted future groundwater recharge rate, actual evapotranspiration rate, and groundwater level, together with future precipitation data from WRF, were used in a three-dimensional (3D) model, which was validated based on rich historic data set collected from 1993-1996, to predict nitrate concentration in soil and groundwater from the year 2057 to 2060. Future groundwater recharge was found to be decreasing in the study area compared to average groundwater recharge data from the literature. Correspondingly, groundwater elevation was predicted to decrease (1 to 2 ft) over the five years of simulation. Predicted higher transpiration data from climate model resulted in lower infiltration of nitrate concentration in subsurface within the root zone.

Nitrogen Species in Soil, Sediment, and Ground Water at a Former Sewage-Treatment Wastewater Lagoon: Naval Air Station Whidbey Island, Island County, Washington

USGS Publications Warehouse

Cox, S.E.; Dinicola, R.S.; Huffman, R.L.

2007-01-01

The potential for contamination of ground water from remnant sewage sludge in re-graded sediments of a deconstructed sewage-treatment lagoon was evaluated. Ground-water levels were measured in temporary drive-point wells, and ground-water samples were collected and analyzed for nutrients and other water-quality characteristics. Composite soil and sediment samples were collected and analyzed for organic carbon and nitrogen species. Multiple lines of evidence, including lack of appreciable organic matter in sediments of the former lagoon, agronomic analysis of nitrogen, the sequestration of nitrogen in the developing soils at the former lagoon, and likely occurrence of peat deposits within the aquifer material, suggest that the potential for substantial additions of nitrogen to ground water beneath the former sewage lagoon resulting from remnant sewage sludge not removed from the former lagoon are small. Concentrations of nitrogen species measured in ground-water samples were small and did not exceed the established U.S. Environmental Protection Agency's maximum contaminant levels for nitrate (10 milligrams per liter). Concentrations of nitrate in ground-water samples were less than the laboratory reporting limit of 0.06 milligram per liter. Seventy to 90 percent of the total nitrogen present in ground water was in the ammonia form with a maximum concentration of 7.67 milligrams per liter. Concentrations of total nitrogen in ground water beneath the site, which is the sum of all forms of nitrogen including nitrate, nitrite, ammonia, and organic nitrogen, ranged from 1.15 to 8.44 milligrams per liter. Thus, even if all forms of nitrogen measured in ground water were converted to nitrate, the combined mass would be less than the maximum contaminant level. Oxidation-reduction conditions in ground water beneath the former sewage lagoon were reducing. Given the abundant supply of ambient organic carbon in the subsurface and in ground water at the former lagoon, any nitrate that may leach from residual sludge and be transported to ground water with recharge is expected to be quickly denitrified or transformed to nitrite and ammonia under the strongly reducing geochemical conditions that are present. Concentrations of organic carbon, the primary constituent of sewage sludge, in sediments of the former sewage lagoon were less than 1 percent, indicating a near absence of organic matter. The amount of total nitrogen present in the sediments at the former sewage lagoon was only about 25 percent of the amount typically present in developed agricultural soils. The lack of substantial carbon and nitrogen in sediments of the former sewage lagoon indicates that surficial sediments of the former lagoon are essentially devoid of residual sewage sludge. The largest concentration of total nitrogen measured in soil samples from the former sewage lagoon (330 milligrams per kilogram) was used to calculate an estimate of the amount of nitrogen that might be leached from residual sewage sludge by recharge. During the first two years following deconstruction of the former sewage lagoon, the concentration of total nitrogen in recharge leachate might exceed 10 milligrams per liter but the recharge leachate would not likely result in substantial increases in the nitrate concentration in ground water to concentrations greater than the drinking-water maximum contaminant level of 10 milligrams per liter.

Investigation of Underground Hydrocarbon Leakage using Ground Penetrating Radar

NASA Astrophysics Data System (ADS)

Srigutomo, Wahyu; Trimadona; Agustine, Eleonora

2016-08-01

Ground Penetrating Radar (GPR) survey was carried out in several petroleum plants to investigate hydrocarbon contamination beneath the surface. The hydrocarbon spills are generally recognized as Light Non-Aqueous Phase Liquids (LNAPL) if the plume of leakage is distributed in the capillary fringe above the water table and as Dense Non-Aqueous Phase Liquids (DNAPL) if it is below the water table. GPR antennas of 200 MHz and 400 MHz were deployed to obtain clear radargrams until 4 m deep. In general, the interpreted radargram sections indicate the presence of surface concrete layer, the compacted silty soill followed by sand layer and the original clayey soil as well as the water table. The presence of hydrocarbon plumes are identified as shadow zones (radar velocity and intensity contrasts) in the radargram that blur the layering pattern with different intensity of reflected signal. Based on our results, the characteristic of the shadow zones in the radargram is controlled by several factors: types of hydrocarbon (fresh or bio-degraded), water moisture in the soil, and clay content which contribute variation in electrical conductivity and dielectric constants of the soil.

The Determination of Soil-plant Transfer Coefficients of Cesium-137 and Other Elements by γ-Ray Measurement and PIXE Analysis, for use in the Remediation of Fukushima

NASA Astrophysics Data System (ADS)

Ishii, K.; Fujita, A.; Toyama, S.; Terakawa, A.; Matsuyama, S.; Arai, H.; Osada, N.; Takyu, S.; Matsuyama, T.; Koshio, S.; Watanabe, K.; Ito, S.; Kasahara, K.

Edible wild plants growing in the area around the Fukushima Daiichi nuclear power plant remain contaminated. It is important to identify plants with low levels of contamination for the restoration of agriculture in the area. We collected specimens of 10 wild plant species growing in Iitate village which is one of the most highly contaminated areas and also sampled the soil beneath each plant. We measured the specific activity of 137Cs and the concentrations of Na, Mg, Al, Si, P, S, K, Ca, Fe, Zn, Rb and Sr in these samples using a germanium detector and PIXE analysis, respectively. We compared the soil-plant transfer coefficient of 137Cs with those of each element and determined their correlation with 137Cs. It was found that a low Sr transfer coefficient could be used to determine the plants with a low 137Cs transfer coefficient. We suggest that PIXE analysis is a useful analysis technique for agricultural remediation projects in highly contaminated areas around the Fukushima Daiichi nuclear power plant.

Effects of increased soil nitrogen on the dominance of alien annual plants in the Mojave Desert

USGS Publications Warehouse

Brooks, Matthew L.

2003-01-01

1. Deserts are one of the least invaded ecosystems by plants, possibly due to naturally low levels of soil nitrogen. Increased levels of soil nitrogen caused by atmospheric nitrogen deposition may increase the dominance of invasive alien plants and decrease the diversity of plant communities in desert regions, as it has in other ecosystems. Deserts should be particularly susceptible to even small increases in soil nitrogen levels because the ratio of increased nitrogen to plant biomass is higher compared with most other ecosystems.2. The hypothesis that increased soil nitrogen will lead to increased dominance by alien plants and decreased plant species diversity was tested in field experiments using nitrogen additions at three sites in the in the Mojave Desert of western North America.3. Responses of alien and native annual plants to soil nitrogen additions were measured in terms of density, biomass and species richness. Effects of nitrogen additions were evaluated during 2 years of contrasting rainfall and annual plant productivity. The rate of nitrogen addition was similar to published rates of atmospheric nitrogen deposition in urban areas adjacent to the Mojave Desert (3·2 g N m−2 year−1). The dominant alien species included the grasses Bromus madritensis ssp. rubens and Schismus spp. (S. arabicus and S. barbatus) and the forb Erodium cicutarium.4. Soil nitrogen addition increased the density and biomass of alien annual plants during both years, but decreased density, biomass and species richness of native species only during the year of highest annual plant productivity. The negative response of natives may have been due to increased competitive stress for soil water and other nutrients caused by the increased productivity of aliens.5. The effects of nitrogen additions were significant at both ends of a natural nutrient gradient, beneath creosote bush Larrea tridentata canopies and in the interspaces between them, although responses varied among individual alien species. The positive effects of nitrogen addition were highest in the beneath-canopy for B. rubens and in interspaces for Schismus spp. and E. cicutarium.6. The results indicated that increased levels of soil nitrogen from atmospheric nitrogen deposition or from other sources could increase the dominance of alien annual plants and possibly promote the invasion of new species in desert regions. Increased dominance by alien annuals may decrease the diversity of native annual plants, and increased biomass of alien annual grasses may also increase the frequency of fire.7. Although nitrogen deposition cannot be controlled by local land managers, the managers need to understand its potential effects on plant communities and ecosystem properties, in particular how these effects may interact with land-use activities that can be managed at the local scale. These interactions are currently unknown, and hinder the ability of managers to make appropriate land-use decisions related to nitrogen deposition in desert ecosystems.8. Synthesis and applications. The effects of nitrogen deposition on invasive alien plants should be considered when deciding where to locate new conservation areas, and in evaluating the full scope of ecological effects of new projects that would increase nitrogen deposition rates.