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Sample records for sandy sediments analyzing

  1. Analyzing Hurricane Sandy

    NASA Astrophysics Data System (ADS)

    Convertino, Angelyn; Meyer, Stephan; Edwards, Becca

    2015-03-01

    Post-tropical Storm Sandy underwent extratropical transition shortly before making landfall in southern New Jersey October 29 2012. Data from this system was compared with data from Hurricane Ike (2008) which represents a classic hurricane with a clear eye wall and symmetry after landfall. Storm Sandy collided with a low pressure system coming in from the north as the hurricane made landfall on the US East coast. This contributed to Storm Sandy acting as a non-typical hurricane when it made landfall. Time histories of wind speed and wind direction were generated from data provided by Texas Tech's StickNet probes for both storms. The NOAA Weather and Climate program were used to generate radar loops of reflectivity during the landfall for both storms; these loops were compared with time histories for both Ike and Sandy to identify a relationship between time series data and storm-scale features identified on radar.

  2. Colonization dynamics of ciliate morphotypes modified by shifting sandy sediments.

    PubMed

    Risse-Buhl, Ute; Felsmann, Katja; Mutz, Michael

    2014-08-01

    Sandy stream-bed sediments colonized by a diverse ciliate community are subject to various disturbance regimes. In microcosms, we investigated the effect of sediment shifting on the colonization dynamics of 3 ciliate morphotypes differing in morphology, behavior and feeding strategy. The dynamics of the ciliate morphotypes inhabiting sediment pore water and overlying water were observed at 3 sediment shifting frequencies: (1) stable sediments, (2) periodically shifting sediments such as migrating ripples, and (3) continuously shifting sediments as occurring during scour events of the uppermost sediment. Sediment shifting significantly affected the abundance and growth rate of the ciliate morphotypes. The free-swimming filter feeder Dexiostoma campylum was vulnerable to washout by sediment shifting since significantly higher numbers occurred in the overlying water than in pore water. Abundance of D. campylum only increased in pore water of stable sediments. On the contrary, the vagile grasper feeder Chilodonella uncinata and the sessile filter feeder Vorticella convallaria had positive growth rates and successfully colonized sediments that shifted periodically and continuously. Thus, the spatio-temporal pattern of sediment dynamics acts as an essential factor of impact on the structure, distribution and function of ciliate communities in sand-bed streams. PMID:25129834

  3. Sediment yield and connectivity in a gullied sandy catchment

    NASA Astrophysics Data System (ADS)

    Lucía, Ana; Francisco Martín-Duque, José; Laronne, Jonathan B.; Ángel Sanz-Santos, Miguel

    2014-05-01

    Badland areas are considered to have high connectivity of sediment at the catchment scale; however, little is known about processes occurring in gullies and badlands developed in sands. This type of gullies is quite common in the Central-Eastern Iberian Peninsula and is associated with historic mining. The sandy badlands also appear in both abandoned and traditionally reclaimed mines, generating on- and offsite environmental effects. Our aim is to quantify the rates of the different processes occurring in the sandy gullied catchments, as well as their coupling and connectivity at a catchment scale. This may allow application to improve reclamation practice in mines and quarries located in sandy materials. The study site is a small (1.32 ha) gullied catchment, the Barranca de los Pinos, which is located in the Northern Piedmont of the Guadarrama Mountains (Central Spain). The catchment area has been divided into Homogeneous Response Units (HRUs) attending to the dominant active process . The sediment produced in the different HRUs has been monitored by a variety of methods: repeat Terrestrial Laser Scanning of high gradient slopes, closed microplots in low gradient slopes and automatic (Reid type) slot bedload samplers and siphon samplers to monitor suspended sediment transport in the channel. During the 2010-11 monitoring period the sediment yield due to gravitational movements in high gradient slopes varied from 20 to 200 kg m-2y-1. In the low gradient slopes the splash and non-concentrated runoff generated 0.1 - 6 kg m-2y-1,while the channel yielded 7.44 ± 1.08 kg m-2y-1 with a very high proportion (>70%) of bedload. Despite the difficulties of extrapolating and comparing the results obtained at different spatial and temporal resolutions, annual patterns of erosion and transport of sediments within the sandy gullied catchments have been identified. These confirm that the transport of sediment in this catchment is limited by the capacity of flow events to

  4. Comparison of wastewater-associated contaminants in the bed sediment of Hempstead Bay, New York, before and after Hurricane Sandy.

    PubMed

    Fisher, Shawn C; Phillips, Patrick J; Brownawell, Bruce J; Browne, James P

    2016-06-30

    Changes in bed sediment chemistry of Hempstead Bay (HB) have been evaluated in the wake of Hurricane Sandy, which resulted in the release of billions of liters of poorly-treated sewage into tributaries and channels throughout the bay. Surficial grab samples (top 5cm) collected before and (or) after Hurricane Sandy from sixteen sites in HB were analyzed for 74 wastewater tracers and steroid hormones, and total organic carbon. Data from pre- and post-storm comparisons of the most frequently detected wastewater tracers and ratios of steroid hormone and of polycyclic aromatic hydrocarbon concentrations indicate an increased sewage signal near outfalls and downstream of where raw sewage was discharged. Median concentration of wastewater tracers decreased after the storm at sites further from outfalls. Overall, changes in sediment quality probably resulted from a combination of additional sewage inputs, sediment redistribution, and stormwater runoff in the days to weeks following Hurricane Sandy. PMID:27045048

  5. Comparison of wastewater-associated contaminants in the bed sediment of Hempstead Bay, New York, before and after Hurricane Sandy

    USGS Publications Warehouse

    Fisher, Shawn C.; Phillips, Patrick; Brownawell, Bruce J.; Browne, James

    2016-01-01

    Changes in bed sediment chemistry of Hempstead Bay (HB) have been evaluated in the wake of Hurricane Sandy, which resulted in the release of billions of liters of poorly-treated sewage into tributaries and channels throughout the bay. Surficial grab samples (top 5 cm) collected before and (or) after Hurricane Sandy from sixteen sites in HB were analyzed for 74 wastewater tracers and steroid hormones, and total organic carbon. Data from pre- and post-storm comparisons of the most frequently detected wastewater tracers and ratios of steroid hormone and of polycyclic aromatic hydrocarbon concentrations indicate an increased sewage signal near outfalls and downstream of where raw sewage was discharged. Median concentration of wastewater tracers decreased after the storm at sites further from outfalls. Overall, changes in sediment quality probably resulted from a combination of additional sewage inputs, sediment redistribution, and stormwater runoff in the days to weeks following Hurricane Sandy.

  6. Surface Sediments in the Marsh-Sandy Land Transitional Area: Sandification in the Western Songnen Plain, China

    PubMed Central

    Yu, Xiaofei; Grace, Michael; Zou, Yuanchun; Yu, Xuefeng; Lu, Xianguo; Wang, Guoping

    2014-01-01

    The development of sandification process was studied, by monitoring the changes of sediment characteristics, at marsh-sandy land intersections in China's Songnen region. A series of sediment collection plates were deployed in the region; after one year, sediments in these plates were analyzed for changes of mass and chemical characteristics. The sediment flux and the sand content of the sediments decreased with the increasing longitudinal distance between the sampling site and the centre line of a sand dune. The mean sediment flux was 29±14 kg m−2 yr−1 and 0.6±0.3 kg m−2 yr−1 in the sandy land and marsh, respectively. Strong, positive correlations were found between the concentrations of organic matter, total nitrogen, P, Fe, Ti, V and Zr, all of which were also negatively correlated with the sand content. The concentrations of organic matter, total nitrogen, P, Fe, Ti, V and Zr in the marsh sediment samples were all significantly greater than the corresponding concentrations of the sandy land (p<0.001). Sand content and Ti, V and Zr concentrations all proved to be valid indicators of sandification intensity, and they showed that the marsh could be divided into three distinct zones. Sand expansion extended about 88 m into the marsh. The mean sand content in the sediments of the sandy land was 91% and then 64% in the marsh, which in turn was higher than that of marshes outside the influence of sandification, suggesting that the marsh in the marsh-sandy land transitional area has already undergone extensive sandification in the past. The study results provide information on the wetland's function of indicating and buffering the sandification process. PMID:24932717

  7. Normal incidence reflection loss from a sandy sediment

    NASA Astrophysics Data System (ADS)

    Chotiros, Nicholas P.; Lyons, Anthony P.; Osler, John; Pace, Nicholas G.

    2002-11-01

    Acoustic reflection loss at normal incidence from a sandy sediment, in the Biodola Gulf on the north side of the island of Elba, Italy, was measured in the frequency band 8-17 kHz, using a self-calibrating method. The water depth was approximately 11 m. The mean and standard deviation of the sand grain diameter were 2.25 (0.21 mm) and 0.6 phi, respectively. The reflection loss was measured using an acoustic intensity integral method, which is insensitive to roughness effects within the selected frequency band. The measured value of reflection loss was 11 dB, plus-or-minus2 dB. The result is consistent with previous measurements in the published literature. The computed reflection loss for a flat interface between water and a uniform fluid or visco-elastic medium with the same properties is 8 dB, plus-or-minus1 dB. The theoretical and experimental values do not significantly overlap, which leads to the conclusion that the visco-elastic model is inappropriate. The Biot model is suggested as a better alternative but more work is needed to ascertain the appropriate parameter values. copyright 2002 Acoustical Society of America.

  8. MOBILIZATION AND CHARACTERIZATION OF COLLOIDS GENERATED FROM CEMENT LEACHATES MOVING THROUGH A SRS SANDY SEDIMENT

    SciTech Connect

    Li, D.; Roberts, K.; Kaplan, D.; Seaman, J.

    2011-09-20

    Naturally occurring mobile colloids are ubiquitous and are involved in many important processes in the subsurface zone. For example, colloid generation and subsequent mobilization represent a possible mechanism for the transport of contaminants including radionuclides in the subsurface environments. For colloid-facilitated transport to be significant, three criteria must be met: (1) colloids must be generated; (2) contaminants must associate with the colloids preferentially to the immobile solid phase (aquifer); and (3) colloids must be transported through the groundwater or in subsurface environments - once these colloids start moving they become 'mobile colloids'. Although some experimental investigations of particle release in natural porous media have been conducted, the detailed mechanisms of release and re-deposition of colloidal particles within natural porous media are poorly understood. Even though this vector of transport is known, the extent of its importance is not known yet. Colloid-facilitated transport of trace radionuclides has been observed in the field, thus demonstrating a possible radiological risk associated with the colloids. The objective of this study was to determine if cementitious leachate would promote the in situ mobilization of natural colloidal particles from a SRS sandy sediment. The intent was to determine whether cementitious surface or subsurface structure would create plumes that could produce conditions conducive to sediment dispersion and mobile colloid generation. Column studies were conducted and the cation chemistries of influents and effluents were analyzed by ICP-OES, while the mobilized colloids were characterized using XRD, SEM, EDX, PSD and Zeta potential. The mobilization mechanisms of colloids in a SRS sandy sediment by cement leachates were studied.

  9. Historical tide gauge data and sediment cores put Hurricane Sandy in context

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2012-11-01

    Historical tide gauge data and sediment cores put Hurricane Sandy in context Several studies that put the recent devastating Hurricane Sandy in context were reported on 5 November at the annual meeting of the Geological Society of America in Charlotte, N. C. Stefan Talke of Portland State University explained that old tide gauge data that he and colleagues have been digitizing show that Sandy was the largest hurricane to hit New York in more than 100 years. Compared to the 1893 storm that was the largest in their records, "Hurricane Sandy was much larger, probably about twice as large, in terms of storm surge," he said. Their study is part of an effort to determine whether sea level rise is accelerating.

  10. Sediment Chemistry and Toxicity in Barnegat Bay, New Jersey: Pre- and Post- Hurricane Sandy, 2012-2013.

    USGS Publications Warehouse

    Romanok, Kristin; Szabo, Zoltan; Reilly, Timothy J.; Defne, Zafer; Ganju, Neil Kamal

    2016-01-01

    Hurricane Sandy made landfall in Barnegat Bay, October, 29, 2012, damaging shorelines and infrastructure. Estuarine sediment chemistry and toxicity were investigated before and after to evaluate potential environmental health impacts and to establish post-event baseline sediment-quality conditions. Trace element concentrations increased throughout Barnegat Bay up to two orders of magnitude, especially north of Barnegat Inlet, consistent with northward redistribution of silt. Loss of organic compounds, clay, and organic carbon is consistent with sediment winnowing and transport through the inlets and sediment transport modeling results. The number of sites exceeding sediment quality guidance levels for trace elements tripled post-Sandy. Sediment toxicity post-Sandy was mostly unaffected relative to pre-Sandy conditions, but at the site with the greatest relative increase for trace elements, survival rate of the test amphipod decreased (indicating degradation). This study would not have been possible without comprehensive baseline data enabling the evaluation of storm-derived changes in sediment quality.

  11. Sediment chemistry and toxicity in Barnegat Bay, New Jersey: Pre- and post-Hurricane Sandy, 2012-13.

    PubMed

    Romanok, Kristin M; Szabo, Zoltan; Reilly, Timothy J; Defne, Zafer; Ganju, Neil K

    2016-06-30

    Hurricane Sandy made landfall in Barnegat Bay, October, 29, 2012, damaging shorelines and infrastructure. Estuarine sediment chemistry and toxicity were investigated before and after to evaluate potential environmental health impacts and to establish post-event baseline sediment-quality conditions. Trace element concentrations increased throughout Barnegat Bay up to two orders of magnitude, especially north of Barnegat Inlet, consistent with northward redistribution of silt. Loss of organic compounds, clay, and organic carbon is consistent with sediment winnowing and transport through the inlets and sediment transport modeling results. The number of sites exceeding sediment quality guidance levels for trace elements tripled post-Sandy. Sediment toxicity post-Sandy was mostly unaffected relative to pre-Sandy conditions, but at the site with the greatest relative increase for trace elements, survival rate of the test amphipod decreased (indicating degradation). This study would not have been possible without comprehensive baseline data enabling the evaluation of storm-derived changes in sediment quality. PMID:27158047

  12. Environmental implications of the use of sulfidic back-bay sediments for dune reconstruction - Lessons learned post Hurricane Sandy.

    PubMed

    Plumlee, Geoffrey S; Benzel, William M; Hoefen, Todd M; Hageman, Philip L; Morman, Suzette A; Reilly, Timothy J; Adams, Monique; Berry, Cyrus J; Fischer, Jeffrey M; Fisher, Irene

    2016-06-30

    Some barrier-island dunes damaged or destroyed by Hurricane Sandy's storm surges in October 2012 have been reconstructed using sediments dredged from back bays. These sand-, clay-, and iron sulfide-rich sediments were used to make berm-like cores for the reconstructed dunes, which were then covered by beach sand. In November 2013, we sampled and analyzed partially weathered materials collected from the cores of reconstructed dunes. There are generally low levels of metal toxicants in the reconstructed dune materials. However oxidation of reactive iron sulfides by percolating rainwater produces acid-sulfate pore waters, which evaporate during dry periods to produce efflorescent gypsum and sodium jarosite salts. The results suggest use of sulfidic sediments in dune reconstruction has both drawbacks (e.g., potential to generate acid runoff from dune cores following rainfall, enhanced corrosion of steel bulwarks) and possible benefits (e.g., efflorescent salts may enhance structural integrity). PMID:27210565

  13. Microplastics elutriation from sandy sediments: A granulometric approach.

    PubMed

    Kedzierski, Mikaël; Le Tilly, Véronique; Bourseau, Patrick; Bellegou, Hervé; César, Guy; Sire, Olivier; Bruzaud, Stéphane

    2016-06-15

    Although relatively easy to extract in the marine environment, microplastics are very difficult to recover when they are trapped in sediments. The elutriation column is one of the best tools currently available for extracting plastics from sediment, but with a high sand recovery yield. This study aims to address the following questions: (i) is it possible to use a sedimentological approach to limit the sand recovery? (ii) does the extraction velocity of the sand and plastic particles vary according to density and granulometry? (iii) what is the relative recovery efficiency obtained for dense polymer particles mixed with marine sand? Based on a new granulometric classification, different plastic particle-size fractions are defined. Their extraction velocities are experimentally determined on particles of sediment and different plastics (PA, PVC). The particle recovery experiments indicate that it is possible to extract >90% of dense plastic particles in cases of negligible sand recovery. PMID:27053014

  14. Regional variability in bed-sediment concentrations of wastewater compounds, hormones and PAHs for portions of coastal New York and New Jersey impacted by hurricane Sandy.

    PubMed

    Phillips, Patrick J; Gibson, Catherine A; Fisher, Shawn C; Fisher, Irene J; Reilly, Timothy J; Smalling, Kelly L; Romanok, Kristin M; Foreman, William T; ReVello, Rhiannon C; Focazio, Michael J; Jones, Daniel K

    2016-06-30

    Bed sediment samples from 79 coastal New York and New Jersey, USA sites were analyzed for 75 compounds including wastewater associated contaminants, PAHs, and other organic compounds to assess the post-Hurricane Sandy distribution of organic contaminants among six regions. These results provide the first assessment of wastewater compounds, hormones, and PAHs in bed sediment for this region. Concentrations of most wastewater contaminants and PAHs were highest in the most developed region (Upper Harbor/Newark Bay, UHNB) and reflected the wastewater inputs to this area. Although the lack of pre-Hurricane Sandy data for most of these compounds make it impossible to assess the effect of the storm on wastewater contaminant concentrations, PAH concentrations in the UHNB region reflect pre-Hurricane Sandy conditions in this region. Lower hormone concentrations than predicted by the total organic carbon relation occurred in UHNB samples, suggesting that hormones are being degraded in the UHNB region. PMID:27177500

  15. Regional variability in bed-sediment concentrations of wastewater compounds, hormones and PAHs for portions of coastal New York and New Jersey impacted by hurricane Sandy

    USGS Publications Warehouse

    Phillips, Patrick; Gibson, Cathy A; Fisher, Shawn C.; Fisher, Irene; Reilly, Timothy J.; Smalling, Kelly; Romanok, Kristin; Foreman, William; ReVello, Rhiannon C.; Focazio, Michael J.; Jones, Daniel K.

    2016-01-01

    Bed sediment samples from 79 coastal New York and New Jersey, USA sites were analyzed for 75 compounds including wastewater associated contaminants, PAHs, and other organic compounds to assess the post-Hurricane Sandy distribution of organic contaminants among six regions. These results provide the first assessment of wastewater compounds, hormones, and PAHs in bed sediment for this region. Concentrations of most wastewater contaminants and PAHs were highest in the most developed region (Upper Harbor/Newark Bay, UHNB) and reflected the wastewater inputs to this area. Although the lack of pre-Hurricane Sandy data for most of these compounds make it impossible to assess the effect of the storm on wastewater contaminant concentrations, PAH concentrations in the UHNB region reflect pre-Hurricane Sandy conditions in this region. Lower hormone concentrations than predicted by the total organic carbon relation occurred in UHNB samples, suggesting that hormones are being degraded in the UHNB region.

  16. Study on small-strain behaviours of methane hydrate sandy sediments using discrete element method

    SciTech Connect

    Yu Yanxin; Cheng Yipik; Xu Xiaomin; Soga, Kenichi

    2013-06-18

    Methane hydrate bearing soil has attracted increasing interest as a potential energy resource where methane gas can be extracted from dissociating hydrate-bearing sediments. Seismic testing techniques have been applied extensively and in various ways, to detect the presence of hydrates, due to the fact that hydrates increase the stiffness of hydrate-bearing sediments. With the recognition of the limitations of laboratory and field tests, wave propagation modelling using Discrete Element Method (DEM) was conducted in this study in order to provide some particle-scale insights on the hydrate-bearing sandy sediment models with pore-filling and cementation hydrate distributions. The relationship between shear wave velocity and hydrate saturation was established by both DEM simulations and analytical solutions. Obvious differences were observed in the dependence of wave velocity on hydrate saturation for these two cases. From the shear wave velocity measurement and particle-scale analysis, it was found that the small-strain mechanical properties of hydrate-bearing sandy sediments are governed by both the hydrate distribution patterns and hydrate saturation.

  17. First-Year Downstream Sediment Budget Following the Marmot Dam Removal from the Sandy River, Oregon

    NASA Astrophysics Data System (ADS)

    Podolak, C. J.; Wilcock, P. R.; Pittman, A.

    2008-12-01

    The October 2007 removal of the Marmot Dam, from the Sandy River, OR, provides an opportunity to assess the impact of increased sediment flux on a river channel. The Sandy River drains the west flank of Mt Hood and typically carries a large load of sand and gravel. The 14-meter-tall dam impounded over 750,000 m3 of sediment, only a small amount of which was removed during the decommissioning. Using a one- dimensional modeling approach, it was assessed that the river could transport the accumulated sediment without large adverse impacts downstream of the dam (Cui et al, 2008 - abstract submitted). In order to observe the actual changes to the river due to the dam removal and to test the modeled predictions, a significant monitoring effort has be in place on the Sandy River including bedload and suspended load measurements, discharge measurements, high-fidelity topographic surveys, repeat photography, multiple airborne LIDAR flights, long profile surveys, as well as mapping and characterizing the grain sizes throughout several reaches downstream of the dam. A key step in the quest to describe and predict the spatial distribution of the sediment throughout the downstream reach is to first account for all the sediment (both stored in the reservoir and supplied from upstream). Here, we examine the transport and deposition downstream of the dam through a 2-fraction sediment budget approach using the former dam as the upstream limit of the reach and choosing a the mouth of a bedrock gorge 7 km below the dam site as the downstream limit. Suspended sediment and bedload measurements taken by the USGS just below the dam site (Major et al, 2008 - abstract submitted) are combined with suspended sediment and bedload measurements collected just below the mouth of the gorge and the annual hydrograph to define the sediment fluxes into and out of the reach. Repeat surveys in the reach below the dam (Wallick et al, 2008 - abstract submitted) provide the measure of change in storage

  18. Analyzing Tropical Waves Using the Parallel Ensemble Empirical Model Decomposition Method: Preliminary Results from Hurricane Sandy

    NASA Technical Reports Server (NTRS)

    Shen, Bo-Wen; Cheung, Samson; Li, Jui-Lin F.; Wu, Yu-ling

    2013-01-01

    In this study, we discuss the performance of the parallel ensemble empirical mode decomposition (EMD) in the analysis of tropical waves that are associated with tropical cyclone (TC) formation. To efficiently analyze high-resolution, global, multiple-dimensional data sets, we first implement multilevel parallelism into the ensemble EMD (EEMD) and obtain a parallel speedup of 720 using 200 eight-core processors. We then apply the parallel EEMD (PEEMD) to extract the intrinsic mode functions (IMFs) from preselected data sets that represent (1) idealized tropical waves and (2) large-scale environmental flows associated with Hurricane Sandy (2012). Results indicate that the PEEMD is efficient and effective in revealing the major wave characteristics of the data, such as wavelengths and periods, by sifting out the dominant (wave) components. This approach has a potential for hurricane climate study by examining the statistical relationship between tropical waves and TC formation.

  19. Polycyclic aromatic hydrocarbons (PAHs) in plastic pellets: variability in the concentration and composition at different sediment depths in a sandy beach.

    PubMed

    Fisner, Mara; Taniguchi, Satie; Moreira, Fabiana; Bícego, Márcia C; Turra, Alexander

    2013-05-15

    Plastic pellets have the ability to adsorb organic pollutants such as PAHs. This study analyzed the variability in the concentration and composition of PAHs on plastic pellets sampled up to 1m deep in the sediment of a sandy beach. The toxic potential of PAHs was analyzed, and the possible sources of contamination are discussed. The total PAHs varied, with the highest concentrations in the surface layer; the priority PAHs showed a different pattern. PAHs at greater depths did not reach toxicity levels above the PEL. The composition of PAHs differed between pellets from the shallower and from deeper sediment layers, and was suggested a mixture of sources. These results provided the first information on the depth distribution of PAHs in sandy beaches, associated with plastic pellets; and evidenced the potential environmental risk. Similarly to the abundance of pellets, the toxic potential is underestimated in surface samples. PMID:23582976

  20. Estuarine bed-sediment-quality data collected in New Jersey and New York after Hurricane Sandy, 2013

    USGS Publications Warehouse

    Fischer, Jeffrey M.; Phillips, Patrick J.; Reilly, Timothy J.; Focazio, Michael J.; Loftin, Keith A.; Benzel, William M.; Jones, Daniel K.; Smalling, Kelly L.; Fisher, Shawn C.; Fisher, Irene J.; Iwanowicz, Luke R.; Romanok, Kristin M.; Jenkins, Darkus E.; Bowers, Luke; Boehlke, Adam; Foreman, William T.; Deetz, Anna C.; Carper, Lisa G.; Imbrigiotta, Thomas E.; Birdwell, Justin E.

    2015-01-01

    Bed-sediment samples were collected from June to October 2013 from 167 estuarine sites extending from Cape May, New Jersey, to the New York Harbor and the eastern end of Long Island. Each sampling location and study region was characterized by using geographic information to identify potential contaminant sources. Characterizations included land cover, locations and types of businesses (industrial, financial, and others), spills (sewage, chemical, and others), bulk storage facilities, effluent discharges within 2 kilometers of the sampling point, and discharges within inundated and non-inundated regions near the sampling location. Samples were analyzed for particle size, total organic carbon, metals and trace elements, semivolatile organic compounds, wastewater compounds, hormones, and sediment toxicity. Samples were also screened using x-ray fluorescence, Fourier transform infrared spectroscopy, and x-ray diffraction. In addition, bioassays for endocrine disruptors and protein phosphatase 2A inhibition were conducted. The study was designed to provide the data needed to understand the extent and sources of contamination resulting from Hurricane Sandy, to compare the chemistry and toxicity of estuarine bed sediments before and after the storm, and to evaluate the usefulness of rapid screening and bioassay approaches in disaster settings.

  1. Carbon, nutrient and trace metal cycling in sandy sediments: A comparison of high-energy beaches and backbarrier tidal flats

    NASA Astrophysics Data System (ADS)

    Reckhardt, Anja; Beck, Melanie; Seidel, Michael; Riedel, Thomas; Wehrmann, Achim; Bartholomä, Alexander; Schnetger, Bernhard; Dittmar, Thorsten; Brumsack, Hans-Jürgen

    2015-06-01

    In order to evaluate the importance of coastal sandy sediments and their contribution to carbon, nutrient and metal cycling we investigated two beach sites on Spiekeroog Island, southern North Sea, Germany, and a tidal flat margin, located in Spiekeroog's backbarrier area. We also analyzed seawater and fresh groundwater on Spiekeroog Island, to better define endmember concentrations, which influence our study sites. Intertidal sandy flats and beaches are characterized by pore water advection. Seawater enters the sediment during flood and pore water drains out during ebb and at low tide. This pore water circulation leads to continuous supply of fresh organic substrate to the sediments. Remineralization products of microbial degradation processes, i.e. nutrients, and dissolved trace metals from the reduction of particulate metal oxides, are enriched in the pore water compared to open seawater concentrations. The spatial distribution of dissolved organic carbon (DOC), nutrients (PO43-, NO3-, NO2-, NH4+, Si(OH)4 and total alkalinity), trace metals (dissolved Fe and Mn) as well as sulfate suggests that the exposed beach sites are subject to relatively fast pore water advection, which leads to organic matter and oxygen replenishment. Frequent pore water exchange further leads to comparatively low nutrient concentrations. Sulfate reduction does not appear to play a major role during organic matter degradation. High nitrate concentrations indicate that redox conditions are oxic within the duneward freshwater influenced section, while ammonification, denitrification, manganese and iron reduction seem to prevail in the ammonium-dominated seawater circulation zone. In contrast, the sheltered tidal flat margin site exhibits a different sedimentology (coarser beach sands versus finer tidal flat sands) and nutrients, dissolved manganese and DOC accumulate in the pore water. Ammonium is the dominant pore water nitrogen species and intense sulfate reduction leads to the formation

  2. Predicting the denitrification capacity of sandy aquifers from shorter-term incubation experiments and sediment properties

    NASA Astrophysics Data System (ADS)

    Eschenbach, W.; Well, R.

    2013-02-01

    Knowledge about the spatial variability of denitrification rates and the lifetime of denitrification in nitrate-contaminated aquifers is crucial to predict the development of groundwater quality. Therefore, regression models were derived to estimate the measured cumulative denitrification of aquifer sediments after one year of incubation from initial denitrification rates and several sediment parameters, namely total sulphur, total organic carbon, extractable sulphate, extractable dissolved organic carbon, hot water soluble organic carbon and potassium permanganate labile organic carbon. For this purpose, we incubated aquifer material from two sandy Pleistocene aquifers in Northern Germany under anaerobic conditions in the laboratory using the 15N tracer technique. The measured amount of denitrification ranged from 0.19 to 56.2 mg N kg-1 yr-1. The laboratory incubations exhibited high differences between non-sulphidic and sulphidic aquifer material in both aquifers with respect to all investigated sediment parameters. Denitrification rates and the estimated lifetime of denitrification were higher in the sulphidic samples. For these samples, the cumulative denitrification measured during one year of incubation (Dcum(365)) exhibited distinct linear regressions with the stock of reduced compounds in the investigated aquifer samples. Dcum(365) was predictable from sediment variables within a range of uncertainty of 0.5 to 2 (calculated Dcum(365)/measured Dcum(365)) for aquifer material with a Dcum(365) > 20 mg N kg-1 yr-1. Predictions were poor for samples with lower Dcum(365), such as samples from the NO3- bearing groundwater zone, which includes the non-sulphidic samples, from the upper part of both aquifers where denitrification is not sufficient to protect groundwater from anthropogenic NO3- input. Calculation of Dcum(365) from initial denitrification rates was only successful for samples from the NO3--bearing zone, whereas a lag-phase of denitrification in samples

  3. Predicting long-term denitrification capacity of sandy aquifers from incubation experiments and sediment properties

    NASA Astrophysics Data System (ADS)

    Eschenbach, W.; Well, R.

    2012-07-01

    Knowledge about the spatial variability of denitrification rates and the lifetime of denitrification in nitrate-contaminated aquifers is crucial to predict the development of groundwater quality. Therefore, regression models were derived to estimate the measured denitrification capacity of incubated aquifer sediments from initial denitrification rates and several sediment parameters, namely total sulphur, total organic carbon, extractable sulfate, extractable dissolved organic carbon, hot water soluble organic carbon and potassium permanganate labile organic carbon. For this purpose, we incubated aquifer material from two sandy Pleistocene aquifers in Northern Germany under anaerobic conditions in the laboratory using the 15N tracer technique. The measured long-term denitrification capacities ranged from 0.18 to 56.2 mg N kg-1 yr-1. The laboratory incubations exhibited high differences between non-sulphidic and sulphidic aquifer material in both aquifers with respect to all investigated sediment parameters. Denitrification rates and the estimated lifetime of denitrification were higher in the sulphidic samples. Denitrification capacity measured during one year of incubation (Dcap) was predictable from sediment variables within a range of uncertainty of 0.5 to 2 (calculated Dcap/measured Dcap) for aquifer material with a Dcap > 20 mg N kg-1 yr-1. Predictions were poor for samples with lower Dcap like samples from the NO3--bearing groundwater zone, which includes the non-sulphidic samples, from the upper part of both aquifers where Dcap is not sufficient to protect groundwater from anthropogenic NO3- input. Calculation of Dcap from initial denitrification rates was only successful for samples from the NO3--bearing zone, whereas a lag-phase of denitrification in samples from deeper zones of NO3- free groundwater caused imprecise predictions. Our results thus show that Dcap of sandy Pleistocene aquifers can be predicted using a combination of short-term incubation and

  4. A laboratory experiment of intact polar lipid degradation in sandy sediments

    NASA Astrophysics Data System (ADS)

    Logemann, J.; Graue, J.; Köster, J.; Engelen, B.; Rullkötter, J.; Cypionka, H.

    2011-03-01

    Intact polar lipids (IPLs) are considered biomarkers for living biomass. Their degradation in marine sediments, however, is poorly understood and complicates interpretation of their occurrence in geological samples. To investigate the turnover of IPLs, a degradation experiment with anoxic sandy sediments from the North Sea was conducted. Intact cells of two organisms that do not naturally occur in North Sea sediments were chosen as IPL sources: (i) Saccharomyces cerevisiae, representative for ester-bound acyl lipids that also occur in Bacteria, and (ii) the archaeon Haloferax volcanii, representative for ether-bound isoprenoid lipids. Surprisingly, IPLs with phosphoester-bound head groups showed approximately the same degradation rate as IPLs with glycosidic head groups. Furthermore, the results indicate a relatively fast degradation of S. cerevisiae IPLs with ester-bound moieties (analogs of bacterial membrane lipids) and no significant degradation of archaeal IPLs with ether-bound moieties. Pore water and 16S rRNA-based DGGE analysis showed only a minor influence of the IPL source on microbial metabolism and community profiles. Due to our results, the IPL-based quantification of Archaea and Bacteria should be interpreted with caution.

  5. A laboratory experiment of intact polar lipid degradation in sandy sediments

    NASA Astrophysics Data System (ADS)

    Logemann, J.; Graue, J.; Köster, J.; Engelen, B.; Rullkötter, J.; Cypionka, H.

    2011-09-01

    Intact polar lipids (IPLs) are considered biomarkers for living biomass. Their degradation in marine sediments, however, is poorly understood and complicates interpretation of their occurrence in geological samples. To investigate the turnover of IPLs, a degradation experiment with anoxic sandy sediments from the North Sea was conducted. Intact cells of two organisms that do not naturally occur in North Sea sediments were chosen as IPL sources: (i) Saccharomyces cerevisiae, representative for ester-bound acyl lipids that also occur in Bacteria, and (ii) the archaeon Haloferax volcanii, representative for ether-bound isoprenoid lipids. Surprisingly, IPLs with phosphoester-bound head groups showed approximately the same degradation rate as IPLs with glycosidic head groups. Furthermore, the results indicate a relatively fast degradation of S. cerevisiae IPLs with ester-bound moieties (analogs of bacterial membrane lipids) and no significant degradation of archaeal IPLs with ether-bound moieties. Pore water and 16S rRNA-based DGGE analysis showed only a minor influence of the IPL source on microbial metabolism and community profiles. Due to our results, the IPL-based quantification of Archaea and Bacteria should be interpreted with caution.

  6. Transport behavior of groundwater protozoa and protozoan-sized microspheres in sandy aquifer sediments

    USGS Publications Warehouse

    Harvey, R.W.; Kinner, N.E.; Bunn, A.; MacDonald, D.; Metge, D.

    1995-01-01

    Transport behaviors of unidentified flagellated protozoa (flagellates) and flagellate-sized carboxylated microspheres in sandy, organically contaminated aquifer sediments were investigated in a small-scale (1 to 4-m travel distance) natural-gradient tracer test on Cape Cod and in flow-through columns packed with sieved (0.5-to 1.0-mm grain size) aquifer sediments. The minute (average in situ cell size, 2 to 3 ??m) flagellates, which are relatively abundant in the Cape Cod aquifer, were isolated from core samples, grown in a grass extract medium, labeled with hydroethidine (a vital eukaryotic stain), and coinjected into aquifer sediments along with bromide, a conservative tracer. The 2-??m flagellates appeared to be near the optimal size for transport, judging from flowthrough column experiments involving a polydispersed (0.7 to 6.2 ??m in diameter) suspension of carboxylated microspheres. However, immobilization within the aquifer sediments accounted for a log unit reduction over the first meter of travel compared with a log unit reduction over the first 10 m of travel for indigenous, free-living groundwater bacteria in earlier tests. High rates of flagellate immobilization in the presence of aquifer sediments also was observed in the laboratory. However, immobilization rates for the laboratory-grown flagellates (initially 4 to 5 ??m) injected into the aquifer were not constant and decreased noticeably with increasing time and distance of travel. The decrease in propensity for grain surfaces was accompanied by a decrease in cell size, as the flagellates presumably readapted to aquifer conditions. Retardation and apparent dispersion were generally at least twofold greater than those observed earlier for indigenous groundwater bacteria but were much closer to those observed for highly surface active carboxylated latex microspheres. Field and laboratory results suggest that 2- ??m carboxylated microspheres may be useful as analogs in investigating several abiotic

  7. Transport Behavior of Groundwater Protozoa and Protozoan-Sized Microspheres in Sandy Aquifer Sediments

    PubMed Central

    Harvey, R. W.; Kinner, N. E.; Bunn, A.; MacDonald, D.; Metge, D.

    1995-01-01

    Transport behaviors of unidentified flagellated protozoa (flagellates) and flagellate-sized carboxylated microspheres in sandy, organically contaminated aquifer sediments were investigated in a small-scale (1 to 4-m travel distance) natural-gradient tracer test on Cape Cod and in flow-through columns packed with sieved (0.5-to 1.0-mm grain size) aquifer sediments. The minute (average in situ cell size, 2 to 3 (mu)m) flagellates, which are relatively abundant in the Cape Cod aquifer, were isolated from core samples, grown in a grass extract medium, labeled with hydroethidine (a vital eukaryotic stain), and coinjected into aquifer sediments along with bromide, a conservative tracer. The 2-(mu)m flagellates appeared to be near the optimal size for transport, judging from flowthrough column experiments involving a polydispersed (0.7 to 6.2 (mu)m in diameter) suspension of carboxylated microspheres. However, immobilization within the aquifer sediments accounted for a log unit reduction over the first meter of travel compared with a log unit reduction over the first 10 m of travel for indigenous, free-living groundwater bacteria in earlier tests. High rates of flagellate immobilization in the presence of aquifer sediments also was observed in the laboratory. However, immobilization rates for the laboratory-grown flagellates (initially 4 to 5 (mu)m) injected into the aquifer were not constant and decreased noticeably with increasing time and distance of travel. The decrease in propensity for grain surfaces was accompanied by a decrease in cell size, as the flagellates presumably readapted to aquifer conditions. Retardation and apparent dispersion were generally at least twofold greater than those observed earlier for indigenous groundwater bacteria but were much closer to those observed for highly surface active carboxylated latex microspheres. Field and laboratory results suggest that 2-(mu)m carboxylated microspheres may be useful as analogs in investigating several

  8. Analyze of waves dynamic over an intertidal mudflat of a sandy-gravely estuarine beach - Field survey and preliminary modeling approach

    NASA Astrophysics Data System (ADS)

    Morio, Olivier; Sedrati, Mouncef; Goubert, Evelyne

    2014-05-01

    As well as marine submersion or erosive phenomena, clay-silted sediment in-filling on estuarial and bay beaches are a main issue in these human-attractive areas. Coupled sandy/gravely and clay/silty intertidal areas can be observed in these particular coastal areas, depending of rivers characteristic (discharge of particle, water flow), ocean dynamics (wave exposure, current) and sediments sources. All around the world, sandy/gravely beaches are exposed to punctual or continuous input clay sediments. Vilaine estuary, Bay of Arcachon and Bay of Seine in France, Plymouth Bay in UK and also Wadden Sea in Deutschland are few examples of muddy/sandy coupled or mixed system. The beach of Bétahon (Ambon town, Brittany - France) is located on the external Vilaine estuary and is an example of this issue. This meso-macrotidal intermediate (low tide terrace) beach presents heterogeneous sediments. The upper intertidal zone is composed by sand and gravel and characterized by a steep slope. A very gentle slope characterized the lower part of the beach and is constituted by silt and clay. Clay/sand limit is characterized by a decimetric erosion cliff of mudflat along the beach. In order to understand bed variations and sediment transport of this complex heterogeneous beach, a well understanding of wave dynamic across the beach is necessary. This study focus on wave dynamics over the beach, using field observations and MIKE 21 3D wave numerical model. This paper is a preliminary approach of an upcoming global understanding of this estuarial beach behavior. Swell from deep-sea to near-shore area is modeled over a 100 km² area and real wind, deep sea wave characteristic, river water flow and tidal level are defined as open boundary conditions for the regional model. This last one is based on multiple bathymetric surveys over the last 50 years. Local model, triangular mesh gridded to 5 meters, covering Bétahon beach , is based on topographic and photographic survey of the mudflat

  9. Using diamond-mined sediment discharges to test the paradigms of sandy-beach ecology

    NASA Astrophysics Data System (ADS)

    Pulfrich, Andrea; Branch, George M.

    2014-10-01

    The prevailing view of sandy-shore ecosystems is that they are controlled largely by physical conditions, particularly particle size, slope and wave regime, but it is rarely possible to test this view by experimentally manipulating these attributes. We report a unique opportunity to accomplish this because large-scale alteration of these properties has taken place on the Namibian coast, associated with diamond mining. Elizabeth Bay diamond mine, near Lüderitz, started modern operations in 1991. Since then, 30.8 million tonnes of sediment with a particle size (<1.4 mm) coarser than the native beach sand have been discharged as slurry onto the beach as part of the treatment process. The physical and biological effects of this were monitored on seven occasions between 1993 and 2012, spanning three phases: (1) an initial pre-upgrade phase (1994-2004) with discharges of moderate intensity; (2) doubling of discharges during upgrade of the mine (2005-2008); (3) temporary cessation of mining (2009-2011). These vicissitudes resulted in both spatial and temporal physical changes, including massive beach accretion (350-620 m), overall increases in mean sand particle size and slope and decreases in Dean's Parameter, east-to-west gradients in beach slope, wave height and erosion, and changes in the beach state from dissipative towards reflective conditions. Alteration of physical conditions led to significant macrofaunal changes, with the community structure in the centre of the bay opposite the discharge points shifting from a state dominated by sand mussels to one dominated by peracarid crustaceans, accompanied by reductions in diversity, biomass and abundance. Grossebucht, which lies nearby and is not mined, provided comparative reference samples: physical conditions there changed little, and biotic communities were constant, significantly more diverse and had greater abundances and biomasses than at Elizabeth Bay. The changes in physical conditions and ensuing biological

  10. Transport of bisphenol-A in sandy aquifer sediment: Column experiment.

    PubMed

    Zakari, Sissou; Liu, Hui; Tong, Lei; Wang, Yan; Liu, Jianfeng

    2016-02-01

    The present paper aims to study the transport behavior of bisphenol-A (BPA) in sandy aquifer so as to provide important parameters for the prediction and control of contaminant plume in aquifer. Miscible displacement experiments were conducted and the breakthrough curves (BTCs) were simulated using HYDRUS-1D software. The effects of pore-water velocity (10-52 cm h(-1)) and initial concentration (2.5-40 mg L(-1)) on the sorption were also investigated. The BTCs of BPA fit the linear first-order non-equilibrium two-site model. The parameters such as partition coefficient (K(d)), the fraction of instantaneous adsorption on "Type-1" sites (F), the first order sorption rate coefficient for the kinetic non-equilibrium (type-2) sites (α), the retardation coefficient (R), and sorption capacity (q(column)) were computed. Results showed that BPA transported 0.11-0.83 m with various pore water velocity in sandy sediment column when water flowed 1 m. The sorption of BPA was mainly caused by the instantaneous surface adsorption as F varied from 0.596 to 0.908. The transport velocity of BPA was affected by pore water velocity (v) and followed the linear equation 1/R = 0.0600 + 0.0110v (r(2) = 0.9724). The parameter K(d) were also closely related to v and followed the equation LnK(d) = 1.0023-0.0482v (r(2) = 0.9690). The sorption capacity was more related to the initial BPA concentration (C0) and followed the linear equation q(column) = 0.265 + 0.253C0 (r(2) = 0.9727). The parameter α was affected by both v and C0 whereas F was not dramatically affected by both. PMID:26539704

  11. Erosion and Redeposition of Reservoir Sediment in Response to Removal of Marmot Dam, Sandy River, Oregon

    NASA Astrophysics Data System (ADS)

    Wallick, R.; Major, J. J.; Spicer, K. R.; Rhode, A.; Keith, M.; O'Connor, J. E.; Burkholder, B.; Grant, G.; Tanner, D. Q.; Saunders, D.

    2008-12-01

    The 19 October 2007 removal of the 14-m-high temporary coffer dam standing in stead of Marmot Dam on the Sandy River, Oregon, triggered a rapid sequence of fluvial responses as the ~730,000 m3 of sand and gravel filling the former reservoir was suddenly exposed to an energetic river. Here we report on the rapid erosion and redeposition of this sediment in the minutes, days, and months following breaching of the coffer dam. Our analyses stem from: 1) repeat topographic surveys of the reservoir and downstream channel reach made before and after breaching and after major storm events; 2) repeat and time-lapse photography from locations around the reservoir; and 3) frequent site visits during and immediately after smaller flow events to document modest channel changes. Following mechanical notching of the earthen coffer dam at 17:00 PDT (Pacific Daylight Time), small knickpoints formed on the downstream dam face and migrated up face until they intercepted the dam crest at 17:45 PDT. This interception resulted in rapid vertical erosion of the reservoir sediment, an instantaneous peak discharge of 136 m3/s (compared to an incoming flow of 50 m3/s) as pooled reservoir water drained, and tall (e.g., 1-2 m high) knickpoints migrated upstream at rates exceeding 200 m/hr. Rapid knickpoint migration slowed 200 m upstream from the breach when the channel became superposed on a bedrock outcrop. After the river slid off the bedrock during slightly higher flow, the knickpoint declined in height and moved upstream another 300 m over the next several days at a mean rate of about 1 m/hr. Knickpoint migration over the next 1.5 km of the reservoir progressed episodically, sweeping rapidly through long (~ 400 m) pools but slowing where it intercepted bouldery riffles that had emerged. At the end of high flows in May 2008, the remnant knickpoint had migrated 2 km upstream from the former dam site, resembled a riffle crest approximately 1 m high, but remained 1.5 km downstream from the

  12. Time-lapse imagery of the breaching of Marmot Dam, Oregon, and subsequent erosion of sediment by the Sandy River, October 2007 to May 2008

    USGS Publications Warehouse

    Major, Jon J.; Spicer, Kurt R.; Collins, Rebecca A.

    2010-01-01

    In 2007, Marmot Dam on the Sandy River, Oregon, was removed and a temporary cofferdam standing in its place was breached, allowing the river to flow freely along its entire length. Time-lapse imagery obtained from a network of digital single-lens reflex cameras placed around the lower reach of the sediment-filled reservoir behind the dam details rapid erosion of sediment by the Sandy River after breaching of the cofferdam. Within hours of the breaching, the Sandy River eroded much of the nearly 15-m-thick frontal part of the sediment wedge impounded behind the former concrete dam; within 24-60 hours it eroded approximately 125,000 m3 of sediment impounded in the lower 300-meter-reach of the reservoir. The imagery shows that the sediment eroded initially through vertical incision, but that lateral erosion rapidly became an important process.

  13. Hurricane Sandy deposits on Fire Island, NY: Using washover deposit stratigraphy to understand sediment transport during large storms.

    NASA Astrophysics Data System (ADS)

    La Selle, S.; Gelfenbaum, G. R.; Jaffe, B. E.; Costa, P. J. M.; Lunghino, B.; Bellanova, P.

    2015-12-01

    By examining coastal deposits from modern inundation events, a number of criteria have been developed to help distinguish between onshore storm and tsunami deposits. The presence of sedimentary structures such as planar lamination and foreset beds in storm deposits suggest a dominance of bedload transport, although some tsunami deposits also contain these structures. The presence of normally graded beds in many tsunami deposits is indicative of the dominance of suspended load transport. Understanding how the stratigraphy in modern event deposits develops during inundation and post-deposition modification improves our ability to differentiate between tsunami and storm deposits in the geologic record. We investigated Hurricane Sandy washover deposits on Fire Island, NY a year after the storm in order to describe deposit stratigraphy on sandy barrier islands. Stratigraphic descriptions from trenches, bulk sediment samples, and push cores were collected. So far, grain size and microtextural analyses have been performed on bulk sediment samples. Deposits ranged from 1-100 cm thick and consist of very well-sorted, fine to coarse sand. Elevation profiles of washover features were measured using Differential GPS. Comparisons of GPS elevations to Lidar data from pre- and post-Sandy surveys show that at some locations, the upper 10-40 cm of the deposit had been reworked in the year following Hurricane Sandy. However, there were still areas where the deposit was almost entirely intact, consisting of massive sand layers near the base, overlain by laminated layers. We hypothesize that the lower sand layers represent deposition from overwash carrying sand in suspension that may have occurred during dune breaching. The upper laminated layers are indicative of deposition from bedload transport by successive storm waves. Detailed analyses of vertical grainsize trends will help determine if the lower unstratified sand layers were deposited by one or multiple flows.

  14. Temporal dynamics of gastropod fauna on subtidal sandy sediments of the Ensenada de Baiona (NW Iberian Peninsula)

    NASA Astrophysics Data System (ADS)

    Moreira, J.; Aldea, C.; Troncoso, J. S.

    2010-12-01

    The temporal variation of the gastropod fauna inhabiting sandy sediments of the Ensenada de Baiona (Galicia, Spain) was studied at three subtidal sites from February 1996 to February 1997 by means of quantitative sampling. A total of 5,463 individuals representing 51 gastropod species and 22 families were found. The family Pyramidellidae was the most diverse in number of species (11 species), followed by Rissoidae and Trochidae (4 species each). The dogwhelk, Nassarius reticulatus, and the rissoid snail, Rissoa parva, were the numerically dominant species at the three studied sites; those and other abundant species showed their greatest densities by the end of summer and the beginning of autumn. In general, univariate measures of the assemblage (number of species, abundance, diversity and evenness) showed variations through time; greater values were recorded between summer and autumn depending on the site. Multivariate analyses done on abundance data showed certain seasonality in the evolution of the assemblage as expected for shallow subtidal sandy sediments at temperate latitudes; those seasonal changes were mostly related to variations in abundance of numerically dominant species. Although the measured sedimentary variables did not show significant correlations with faunal univariate parameters, sediment heterogeneity due to the presence of mats of Zostera marina L. and shells of dead bivalves might explain the differences in composition of the gastropod assemblage among sampling sites.

  15. Heavy mineral analysis for assessing the provenance of sandy sediment in the San Francisco Bay Coastal System

    NASA Astrophysics Data System (ADS)

    Wong, F. L.; Woodrow, D. L.; McGann, M. L.

    2012-12-01

    Heavy minerals have been used to trace the sources and transportation of sandy sediment in San Francisco Bay and nearby coastal areas since the 1960s. We have the opportunity to sample similar environments and revisit the heavy mineral populations under the current San Francisco Coastal System study of the provenance of beach sand. Most of the sandy sediment in San Francisco Bay can be traced to distant sources including the Sierra Nevada batholith and associated terranes with local contributions from the Franciscan Complex. Heavy minerals from Sierran sources include ordinary hornblende, metamorphic amphiboles, and hypersthene while those from the Franciscan Complex include other types of pyroxene, epidote, basaltic hornblende, and glaucophane... Tertiary strata and volcanics in the surrounding hills and displaced Sierran rocks found on the continental shelf west of the San Andreas Fault Zone introduce similar minerals, but perhaps in a lesser volume to be identified as major contributors... The primary result of cluster analysis of heavy minerals separated from sand-sized sediment taken within San Francisco Bay, the adjacent continental shelf, local beaches, cliffs outside the Golden Gate, and upstream drainages indicate a widespread occurrence of sediment traceable to the Sierra Nevada. A second cluster of samples identifies samples of mixed Sierran and Franciscan lineage within the strait of the Golden Gate, on the San Francisco bar, and on coastal beaches. Sediment samples with predominantly Franciscan mineral content appear on beaches around Point Reyes, possibly transported from the Russian River. The heavy mineral composition supports transport from the east, through San Francisco Bay and out the Golden Gate to the San Francisco bar and southward.

  16. Effect of mica content on pore-size distribution and porosity of sandy sediment using proton nuclear magnetic resonance measurement

    NASA Astrophysics Data System (ADS)

    Kimura, S.

    2015-12-01

    As a part of a Japanese National hydrate research program (MH21, funded by METI), we performed a study on effect of mica content on pore size distribution and porosity of sandy sediment. This study used proton nuclear magnetic resonance (NMR) to measure the pore-size distribution and porosity of specimen to investigate mica content effect in sandy sediment. A mixture of silica sand No. 7 and mica (mica of 0 wt. %, 5 wt. % and 20 wt. %) was used in this study. The median D50 by laser diffraction method was obtained as 215.7 μm of silica sand No. 7 and 278.9 μm of mica. Pore-size distributions of specimens by the distribution of transverse magnetic relaxation time (T2) measurement by NMR were performed for the water-saturated sample under effective confining pressure of 1.0 MPa. The peaks of pore-size distribution curves decreased and showed finer shifts with increasing of mica content. The porosity of silica sand No. 7 specimen was 46.3%, and that of mica 5% and 20 % were 45.9% and 42.2%m, respectively. A change in pore-size distribution and porosity were observed with an increasing ratio of mica.

  17. Quantifying the role of sandy-silty sediments in generating slope failures during earthquakes: example from the Algerian margin

    NASA Astrophysics Data System (ADS)

    Dan, Gabriela; Sultan, Nabil; Savoye, Bruno; Deverchere, Jacques; Yelles, Karim

    2009-06-01

    The Algerian margin is a seismically active region, where during the last century, several large magnitude earthquakes took place. This study combines geotechnical and sedimentological data with numerical modelling to quantitatively assess the present-day slope stability of the Algerian margin. Geotechnical laboratory tests, such as cyclic triaxial tests, oedometric tests and vane shear tests were carried out on sediment cores collected on the study area. The liquefaction potential of a sediment column located about 30 km from the Boumerdès earthquake epicentre of 21st May 2003 was evaluated theoretically for an earthquake of M w = 6.8. We show that thin sand and silt beds such as those described on recovered sediment cores are the main cause of sediment deformation and liquefaction during earthquakes. Numerical calculations showed that the slope failure may occur during an earthquake characterised by a PGA in excess of 0.1 g, and also that, under a PGA of 0.2 g liquefaction could be triggered in shallow silty-sandy deposits. Moreover, comparison of the predicted slope failure with failure geometries inferred from seafloor morphology showed that earthquakes and subsequent mass movements could explain the present-day morphology of the study area.

  18. Analysis of temperature variability and determination of apparent thermal diffusivity in sandy intertidal sediments at the German North Sea coast

    NASA Astrophysics Data System (ADS)

    Ricklefs, Klaus; Vanselow, Klaus Heinrich

    2012-08-01

    Temperature was measured at depths of 1, 10, 30, 75, and 170 cm in fine sandy intertidal sediments by means of specially-designed "temperature lances". The measurements cover a period from February to October 2007 and have a temporal resolution of 5 min. Stochastic as well as recurrent processes due to the solar cycle and due to tide induces flooding and drying of the sediment surface lead to a complex composition of the time series curves. Spectral analyses based on Fast Fourier Transformation (FFT) reveal that temperature variability at the sediment water/air interface is widely controlled by recurrent processes with period lengths of 4.93, 6.1, 8.19, ˜12, ˜24 h, and 354 h (14.7 days). The importance of the higher frequencies decreases with increasing sediment depth. At a depth of 30 cm the 24 h and the 14.7 days cycles mainly determine the temperature development over time, while at 75 cm sediment depth contour temperature varies only along the 14.7 days cycle, as well as within the seasonal cycle. Using cross-correlation-analysis the time necessary for a temperature signal at the surface to trigger a response at a sediment depth of 10, 30, and 75 cm was calculated as 1.4, 7.0, and 73.1 h respectively. Utilizing an alternate approach, FFT derived temperature peak-to-peak amplitude values and phase angles of up to 9 different cycles were used to calculate apparent thermal diffusivity in different sediment depths. The thermal diffusivity decreases from approximately 6-9 × 10-7 m2 s-1 from the surface down to a sediment depth of 75 cm. The specially-designed instrumentation has proven to be robust and precise enough to record high resolution time series of sediment temperature in different depths. The time series analysis of the data clearly shows that the temperature variability in the intertidal sediments to a high degree can be explained by recurrent solar and/or tidal effects. So the methods and results presented in this paper can help to answer questions

  19. Hurricane Sandy's Impact on Coastal Sedimentation on Long Island's South Shore: Results from a 2013 Rapid Response Study

    NASA Astrophysics Data System (ADS)

    Christensen, B. A.; Goff, J. A.; Flood, R. D.; Austin, J. A., Jr.; Browne, C. M.; Saustrup, S.

    2014-12-01

    To understand the impact of Hurricane Sandy on the NY coast, we conducted subsurface and multi-beam analyses, ground-truthed by grab samples, in 3 areas: the western end of Fire Island (FIW), eastern Fire Island (FIE) where a new inlet formed during the storm, and Long Beach (LB). Grab samples yielded sands and muds, a surprise given the shallow (10-25m) water depths. Muds rested on top of sands and were removed for additional analyses. Since percent mud could not be determined absolutely, sediments were washed through a 63 mm sieve, RoTapped for 10 minutes at ¼ Φ, and weight percent calculated for the coarse fraction. At FIW and FIE, fine sands dominate the shallowest depths studied, consistent with previous studies. At FIE, the sedimentary wedge extends to ~15m, with finest sands (peak 3-3.5 Φ) in shallowest waters surveyed (~10m). Slightly coarser (2.5Φ) sediments plus relict gravels are present in swales where the wedge shoals. This supports mapping results indicating sand ridges migrated to the SW. Medium to fine sand is present at the deepest extent of the wedge; the grain size distribution matches a sample taken in the swash zone on the eastern flank of the new breach. Sediments may have been transported shoreward and then reworked post-Sandy. Samples seaward of the new breach were capped by a mud layer, which in turn had a layer of fine sand resting on it, evidence of a nascent ebb tidal deposit. At FIW, sediments in the shallow NE swale are finer (3.5Φ) and better sorted. As the region is underlain by relict sediments, these fine sands may be relicts exposed by storm-driven bedform migration. Deeper water (~22m w.d.) samples at FIW are coarser and contain shell hash. Sand on the lee side of the sand ridge, which CHIRP profiles show did not migrate significantly and accumulated sands, are medium (1.5 Φ), and match the grain sizes found on Fire Island beach. Muds contain heavy metals in concentrations consistent with transport from adjacent estuaries.

  20. Occurrence of authigenic beidellite in the Eocene transitional sandy sediments of the Chu-Saryssu basin (South-Central Kazakhstan)

    NASA Astrophysics Data System (ADS)

    Robin, Valentin; Hebert, Benoit; Beaufort, Daniel; Sardini, Paul; Tertre, Emmanuel; Regnault, Olivier; Descostes, Michael

    2015-05-01

    This paper describes the petrographic properties and the clay mineralogy of Eocene sandy sediments of the Chu-Saryssu basin (South-Central Kazakhstan), in which dioctahedral smectite formed during shallow burial diagenesis (eogenesis). Evidence from petrography and clay mineralogy supports the successive occurrence of kaolinite and dioctahedral smectite during the eogenetic processes, which may have resulted from a change from wet and humid to semi-arid or arid climatic conditions. An original result of this study is the predominantly beidellitic nature of the authigenic smectite, which was determined via X-ray diffraction (XRD, using the Hofmann-Klemen test) and Fourier transform infrared spectroscopy (FTIR) investigations and chemical microanalysis. The crystal-chemical investigations indicate a rather homogeneous chemical composition of the smectite at the regional scale, and the following unit formula is proposed: (Si4 +3.65Al3 +0.35)(Al3 +1.65Fe3 +0.21Mg2 +0.14)O10(OH)2Na+0.10Mg2 +0.11Ca2 +0.04K+0.07. This type of smectite has been interpreted as representative of mixed layers of montmorillonite and beidellite. The fact that the smectite that formed primarily in the unconsolidated sandy sediments is close to beidellite, rather than montmorillonite, may have a major impact on the rate of further illitization in the Chu-Saryssu basin. Indeed, the crystal chemistry of beidellite is more favorable to illitization, and the presence of this mineral provides new insights concerning the different rates of illitization between sandstones and shale formations observed worldwide.

  1. SANDY: A Matlab tool to estimate the sediment size distribution from a sieve analysis

    NASA Astrophysics Data System (ADS)

    Ruiz-Martínez, Gabriel; Rivillas-Ospina, Germán Daniel; Mariño-Tapia, Ismael; Posada-Vanegas, Gregorio

    2016-07-01

    This paper presents a new computational tool called SANDY© which calculates the sediment size distribution and its textural parameters from a sieved sediment sample using Matlab®. The tool has been developed for professionals involved in the study of sediment transport along coastal margins, estuaries, rivers and desert dunes. The algorithm uses several types of statistical analyses to obtain the main textural characteristics of the sediment sample (D50, mean, sorting, skewness and kurtosis). SANDY© includes the method of moments (geometric, arithmetic and logarithmic approaches) and graphical methods (geometric, arithmetic and mixed approaches). In addition, it provides graphs of the sediment size distribution and its classification. The computational tool automatically exports all the graphs as enhanced metafile images and the final report is also exported as a plain text file. Parameters related to bed roughness such as Nikuradse and roughness length are also computed. Theoretical depositional environments are established by a discriminant function analysis. Using the uniformity coefficient the hydraulic conductivity of the sand as well as the porosity and void ratio of the sediment sample are obtained. The maximum relative density related to sand compaction is also computed. The Matlab® routine can compute one or several samples. SANDY© is a useful tool for estimating the sediment textural parameters which are the basis for studies of sediment transport.

  2. Santa Ana River: An example of a sandy braided floodplain system showing sediment source area imprintation and selective sediment modification

    NASA Astrophysics Data System (ADS)

    Haner, Barbara E.

    1984-03-01

    The Santa Ana River floodplain can be divided into five geomorphic environments recognized by both morphology and sedimentary characteristics: braided channels, bars, vegetated islands, sand flats and floodplain terraces. Braided channels which vary in width from 30 to 80 m and are bordered by sand flats, flow round vegetated islands and emergent mid-channel bars. Deep braided channels have linguoid dume bedforms which are reworked during falling flood stages. If channel bars emerge in early spring, vegetation is rapidly established and they may become vegetated islands. Bars emerging in minor channels and in areas of increased channel width may develop into extensive sand flats. Away from the channel margins, sand flats are subject to wind erosion as the water table declines in summer and fall. This sediment is deposited in sand sheets and vegetated dunes. These distal sand flat environments are characterized by a well-sorted, medium sand-sized sediment population and are separated from negatively skewed, moderately sorted coarse channel sands by a mixed sediment population along channel margins. The drainage basin discharge is dominated by the regional Mediterranean climate. The coarse channel sediment reflects the large temporal variations in drainage discharge and the resulting greater variability and competence to transport sediment. Major decreases in channel width during both seasonal summer drought and prolonged periodic drought exposes large areas of the floodplain to selective wind winnowing of fluvially derived sediment. This process operates on a small scale today, but during arid conditions in the late Wisconsin interglacial interval (prior to 22,000 yrs B.P.) extensive sand flats along the Santa Ana River, distal alluvial fans, and sediment from minor tributaries were the sediment source for a major riverine dune field adjacent to the floodplain. This dune field was stabilized during the late Wisconsin glacial interval. Subsequent channel entrenchment

  3. Airflow and sediment movement within an inland blowout in Hulun Buir sandy grassland, Inner Mongolia, China

    NASA Astrophysics Data System (ADS)

    Sun, Yu; Hasi, Eerdun; Liu, Meiping; Du, Huishi; Guan, Chao; Tao, Binbin

    2016-09-01

    We measured wind flows and sediment transport rates through a blowout in Hulun Buir grassland, Inner Mongolia. Topography and the angle of incidence between the approaching wind and the blowout long-axis significantly affected the air flow. Flow separated and decelerated at the western wall and accelerated towards the east, until maximum wind speed occurred at the top of the depositional lobe, and then decelerated on the lee side. When airflow emerged on the eastern wall, resultant directions were always NW. When winds approached from directions within 17.5° of the blowout axis, both the northwestern and southwestern walls developed turbulent flow, and significant topographic steering occurred. The deceleration zone expanded eastwards from 10.3 to 12.8 m from the western rim. When the wind direction was more oblique than 17.5°, turbulent flow at the southwestern wall disappeared. 'S-shaped' flow intensified, causing more pronounced steering at the bottom, but topographic steering elsewhere was reduced, and the boundary of the deceleration moved to 10 m from the western rim. Minor sediment deposition occurred on the western wall, while other parts were eroded; maximum sediment transport occurred at the top of the depositional lobe. The approaching wind speed affected the sediment transport rate more than the direction; and spatial variability in sediment transport reflected differences in compaction, vegetation coverage, slope, aspect, and upwind sediment availability, resulting in asymmetrical development. Overall, flow-form interactions governed the flow structures and controlled the evolution of the blowout via sediment transport.

  4. Stable isotope biogeochemistry of the sulfur cycle in modern marine sediments: I. Seasonal dynamics in a temperate intertidal sandy surface sediment.

    PubMed

    Böttcher, Michael; Hespenheide, Britta; Brumsack, Hans-Jürgen; Bosselmann, Katja

    2004-12-01

    A biogeochemical and stable isotope geochemical study was carried out in surface sediments of an organic-matter poor temperate intertidal sandy surface sediment (German Wadden Sea of the North Sea) to investigate the activity of sulfate-reducing bacteria and the dynamics of the vertical partitioning of sedimentary sulfur, iron, and manganese species in relation to the availability of total organic carbon (TOC) and mud contents. The contents and stable isotopic compositions ((34)S/(32)S) of total reduced inorganic sulfur species (TRIS) and dissolved sulfate were measured. Maximum oxygen penetration depths were estimated from the onset of a blackening of the sediments due to FeS accumulation and ranged from 5 to 10 mm below surface (mmbsf). A zone of relatively moderate relative organic-matter enrichment was found between 5 and 20 mmbsf leading to enhanced activities of sulfate-reducing bacteria with sulfate-reduction rates (SRR) up to 350 nmol cm(-3) d(-1). Below this zone, microbial SRR dropped significantly. Depth integrated SRR seem to depend not only on temperature but also on the availability of reactive organic matter. The sulfur-isotopic composition of TRIS was depleted in (34)S by 33-40 per thousand with respect to coexisting dissolved sulfate (constant at about +21 per thousand vs. Vienna-Canyon Diablo Troilite (V-CDT)). Since sulfate reduction is not limited by dissolved sulfate (open system), depth variations of the isotopic composition of TRIS reflect changes in overall isotope effect due to superimposed microbial and abiotic reactions. Most of the solid-phase iron and manganese was bonded to (non-reactive) heavy minerals. However, a layer of reactive Fe(III) and Mn(IV) oxi(hydroxi)des was found in the uppermost sediment section due to re-oxidation of dissolved Fe(II) and Mn(II) species at the sediment-water interface. Metal cycling below the surface is at least partially coupled to intense sulfur cycling. PMID:15621745

  5. Behavior and Fate of PFOA and PFOS in Sandy Aquifer Sediment (journal)

    EPA Science Inventory

    Microcosms were constructed with sediment from beneath a landfill that received waste containing PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonate). The microcosms were amended with PFOA and PFOS, and sampled after 91, 210, 343, 463, 574, and 740 days of incubat...

  6. Effects of sandy vs muddy sediments on the vertical distribution of microphytobenthos in intertidal flats of the Fraser River Estuary, Canada.

    PubMed

    Yin, Kedong; Zetsche, Eva-Maria; Harrison, Paul J

    2016-07-01

    Benthic algae or microphytobenthos (MPB) in intertidal flats play an important role in the sediment and overlying water ecosystems. We hypothesize that there are effects of sediment texture on the vertical distribution of MPB using chlorophyll a (chl a) as a proxy for MPB biomass and present results over a 2.5-year period. Four sites were sampled monthly: two sandy sites (A10 and A12) and two muddy sites (A0 and A14) on the intertidal flats of the Fraser River Estuary. At the two sandy sites, pigments were distributed down to 10 cm. High ratios of depth-integrated chl a to phaeopigments suggest that the chl a had been recently buried. In contrast, at the muddy sites, pigments were limited to the top 4 cm, with MBP in the top 1 cm contributing up to 60 % of the whole sediment core pigments. As a result, the depth-integrated chl a values were on average 2,044 mg m(-2) (160-4,200) at A10 and 882 mg m(-2) (183-2,569) at A12, the two sandy sites, and much higher than at the two muddy sites where averages of 84 mg m(-2) (41-174) and 235 mg m(-2) (77-854) were measured at A0 and A14, respectively. Despite these lower concentrations at the muddy sites than at the sandy sites, particulate organic carbon (POC) and nitrogen (PON) concentrations showed a homogenous vertical distribution at the two sandy sites. Such a homogeneous vertical distribution of chl a, POC, and PON suggests that vertical transport mechanisms were actively transporting organic material into and out of the sediment. These results suggest that MBP on sandy sediments play a very active role in providing food for herbivores and are interacting with the overlying water column in the sediment-water exchange processes during tidal cycles. PMID:27053045

  7. Eruption-related lahars and sedimentation response downstream of Mount Hood: Field guide to volcaniclastic deposits along the Sandy River, Oregon

    USGS Publications Warehouse

    Pierson, Tom C.; Scott, William E.; Vallance, James W.; Pringle, Patrick T.

    2009-01-01

    Late Holocene dome-building eruptions at Mount Hood during the Timberline and Old Maid eruptive periods resulted in numerous dome-collapse pyroclastic flows and lahars that moved large volumes of volcaniclastic sediment into temporary storage in headwater canyons of the Sandy River. During each eruptive period, accelerated sediment loading to the river through erosion and remobilization of volcanic fragmental debris resulted in very high sediment-transport rates in the Sandy River during rain- and snowmelt-induced floods. Large sediment loads in excess of the river's transport capacity led to channel aggradation, channel widening, and change to a braided channel form in the lowermost reach of the river, between 61 and 87 km downstream from the volcano. The post-eruption sediment load moved as a broad bed-material wave, which in the case of the Old Maid eruption took ~2 decades to crest 83 km downstream. Maximum post-eruption aggradation levels of at least 28 and 23 m were achieved in response to Timberline and Old Maid eruptions. In each case, downstream aggradation cycles were initiated by lahars, but the bulk of the aggradation was achieved by fluvial sediment transport and deposition. When the high rates of sediment supply began to diminish, the river degraded, incising the channel fills and forming progressively lower sets of degradational terraces. A variety of debris-flow, hyperconcentrated-flow, and fluvial (upper and lower flow regime) deposits record the downstream passage of the sediment waves that were initiated by these eruptions. The deposits also presage a hazard that may be faced by communities along the Sandy River when volcanic activity at Mount Hood resumes.

  8. Influence of Trypaea australiensis population density on benthic metabolism and nitrogen dynamics in sandy estuarine sediment: A mesocosm simulation

    NASA Astrophysics Data System (ADS)

    Jordan, Mark A.; Welsh, David T.; Dunn, Ryan J. K.; Teasdale, Peter R.

    2009-02-01

    surprisingly T. australiensis population density had no effect on rates of denitrification and DNRA despite the higher rates of nitrification and higher equilibrium water column nitrate concentration. Indeed, nitrate reduction processes became an increasingly unimportant element with increasing yabby density with for example, N 2 generated by coupled nitrification-denitrification representing 11.5, 5.2 and 2.8% of the total inorganic-N recycled to the water column in the control, low density and high density yabby treatments, respectively. Overall, the major influence of T. australiensis in the studied low organic matter content, sandy sediments was to enhance coupling between the benthic and pelagic systems through increased rates of inorganic nitrogen regeneration in the sediment and enhanced export of this nitrogen to the water column. Our results also suggest that the influences of organisms such as T. australiensis which form deep, extensive and complex burrow systems where irrigation rates differ greatly between different burrow sections, may be more complex than those recorded for infauna which form simple U-shaped burrows. Additionally, there may be a strong interaction between faunal effects and the sediment physical and biological environment and thus the same species may have contrasting influences in different sediment types.

  9. The sandy inner shelf as a repository for muddy sediment: an example from Northern California

    NASA Astrophysics Data System (ADS)

    Crockett, J. S.; Nittrouer, C. A.

    2004-01-01

    To understand the sedimentary history of a siliciclastic, tectonically active inner-shelf environment, 50 vibracores were collected in water depths ranging from 20 to 55 m on the Eel margin, Northern California. Sediments exhibit changes in grain size along- and across-shelf, as well as vertically. The mean grain size of the surface sand fraction is 2.2-3.6 φ (217-82.5 μm), with 7-40% of the sediment finer than 4 φ (64 μm). The along-shelf distribution of sand is controlled predominantly by proximity to the sediment source and by the prevailing oceanic conditions (e.g., waves and currents). Fine sand dominates within ˜10 km of the Eel River mouth, which is consistent with sediment settling velocities out of the Eel River plume. Coarser sediment is found farther (>10 km) north of the Eel River mouth, and may have a source other than the modern Eel River. Cores tend to demonstrate upward fining (except cores collected at ˜30 m) and other vertical grain-size variations, which preserve the record of floods on the Eel margin. Muddy layers, which are assumed to record large floods, are found interbedded with sand. Two types of muddy layers are observed. "Distinct" mud layers have >70% mud and are identifiable through visual observation and a decrease in bulk density. "Diffuse" mud layers contain only 5-15% mud due to reworking caused by wave activity during or after deposition. Diffuse mud layers are not visually obvious, and poor sorting increases their bulk density. Recent flood layers have detectable 210Pb and 137Cs, and the deepest detectable 137Cs is 120 cm below the surface. Assuming that the mud layers result from major floods (e.g., 1964), and using 210Pb and 137Cs radioisotopes to establish chronological control, the accumulation rate of sand on the inner shelf since 1964 ranges from 1.3 to 3.3 cm/yr. Approximately 6-13% of the fine-grained sediment discharged by the Eel River over the past 36 yr is accumulating interspersed with the inner-shelf sand. An

  10. Numerical modelling of pore-pressure measurements in saturated sandy seabed sediments

    SciTech Connect

    Magda, W.

    1995-12-31

    The question of model conditions (i.e., saturation procedure and temporal dewatering of soil model, as well as existence of a geotextile on the top of seabed model and existence of pore-pressure transducers itself in seabed sediments) in large-scale modelling is discussed with respect to the quality of measured pore-pressure values. The meaning of locally unsaturated zones within the seabed model, due to an improper installation procedure or man-made mistake during the testing period, are illustrated by some example computations, based on 2-D finite-element model, the results of which are presented in terms of the momentaneous pore-pressure distribution with depth, induced by surface harmonic waves passing over the seabed.

  11. Sandy inland braidplain deposition with local aeolian sedimentation in the lower and middle parts of the buntsandstein and sandy coastal braidplain deposition in the topmost zechstein in the sudetes (Lower Silesia, Poland)

    NASA Astrophysics Data System (ADS)

    Mroczkowski, Jerzy; Mader, Detlef

    The lower and middle parts of the Buntsandstein between Röt and Zechstein in the Sudetes (Lower Silesia, Poland) crop out in the marginal seams of the North Sudetic Trough and the Intra Sudetic Trough. The continental red beds originate in predominantly sandy braided river systems of an extensive inland alluvial plain in almost arid climate. The sediments are laid down in channels and floodplains of a moderately- to highly-braided, sandy to pebbly stream complex consisting of narrowly- to moderately-spaced low-sinuosity watercourses and narrow to wide overbank plains between the channels. Rapid aggradation and abandonment, quick lateral migration or high avulsion rates of the considerably mobile streams result in effective combing of the interchannel areas. Persistent high-energy overspilling of watercourse banks and invasion of bed-load-saturated flood surges into the overbank areas often lead to primary restriction or even suppression of formation of topstratum suspension fines. Secondarily, the silty-clayey and fine sandy overbank sediments which could occasionally originate in remote or sheltered lakes and ponds are frequently completely reworked by considerable lateral and vertical erosion during sidewards displacement of the rivers. As a result of both primary-depositional restriction and secondary-erosional removal of floodplain fines, the channel sediments are commonly stacked upon each other to multistorey stream sand complexes. Emergence and desiccation of parts of the alluvial plain sometimes give rise to aeolian deflation and accumulation of the winnowed sand to small dunelets and wind ripple trains. The aeolian depositional environment representing a more peripheral erg facies with sheet sand interdune milieu could not be fully ascertained due to poor outcrop conditions, but is likely to occur locally in view of comparative interpretation with other mixed dune and river sand sequences in the Mid-European Buntsandstein. Variations of fluvial style are

  12. Early Diagenesis of Subseafloor Sandy Sediments Closely Related to Gas Hydrate Occurrences and Their Provenances in the Eastern Margin of Japan Sea

    NASA Astrophysics Data System (ADS)

    Uchida, T.; Sakai, H.; Horiuchi, S.; Matsumoto, R.

    2015-12-01

    A lot of effort have been put into recovering gas hydrate, methane induced carbonate, and associated sediments in order to develop the geologic model of gas hydrate accumulation and evaluate its possible environmental impact for the last glacial-interglacial cycles. Having investigated gas hydrate occurrences in the eastern margin of Japan Sea revealed wide distributions of chimney-shape gas hydrate concentrations beneath the seafloor, confirmed off Shimane and off Akita/Yamagata as well as off Joetsu (Niigata), which are quite different from the occurrences of pore space hydrate filling intergranular pore systems of sands recognized in Nankai Trough, Mallik and other sites. Many sediment samples have been obtained below from the Umitaka Spur, Joetsu Channel, Toyama Trough, Mogami Trough and Okushiri Ridge areas. Small amounts of sandy sediment have been retrieved as thin intercalations in Holocene and Pleistocene silty/muddy layers, where trace fossils and strong bioturbations are commonly observed. Sandy sediments consist of very fine- to fine-grained sand grains, and are sometimes tuffaceous. Pore-size distribution measurements and thin-section observations of these sands were carried out, which indicate that porosities of silty sediments are around 50 % but those of arenites range from 42 to 52 %, of which mean pore sizes and permeabilities are larger than those of silty sediments. These coarser sediments might have been transported approximately around 3 to 30 ka due to the tephra ages, where supplying sediments might be abundant due to sea level fluctuation during the Pleistocene ice age. Sandy sediments contain not only detrital quartz and feldspar but mafic minerals (pyroxene, amphibole and mica), contents of which may indicate their provenances. Silty/muddy sediments usually contain diatom tests, foraminifers and framboidal pyrites, and, in particular, the shapes of diatom are usually various, dominantly fragmental and infrequently preserved. It is

  13. Denitrification activity of aquifer material from two different sandy aquifers in northern Germany measured by laboratory incubation experiments in relation to influencing sediment parameters

    NASA Astrophysics Data System (ADS)

    Eschenbach, Wolfram; Well, Reinhard; Flessa, Heiner; Duijnisveld, Wilhelmus H. M.; Walther, Wolfgang

    2010-05-01

    In NO3¯ contaminated aquifers containing reduced compounds like organic carbon or sulfides, denitrification is an intense process. Its characterization is of interest because NO3¯ consumption improves water quality and N2O production can cause emission of this greenhouse gas to the atmosphere. Spatial distribution of NO3¯ and N2 produced by denitrification in groundwater (excess N2) reflects the NO3¯ input as well as cumulative denitrification during aquifer passage. The amount and spatial distribution of reduced compounds within denitrifying aquifers is not well known. Recent findings from parallel investigations on in situ denitrification and reactive compounds suggests that single-well 15N tracer tests might be suitable to characterize the stock of reduced compounds in aquifers (Konrad 2008), but an evaluation of this approach has not been realized until now. The overall objective of our studies is to measure the spatial and long-term dynamics of denitrification within two sandy aquifers in northern Germany. This includes measurement of the actually occurring denitrification process in the field by 15N-tracer experiments and incubation experiments with corresponding aquifer material. Beside the comparison of field and laboratory data concerning the denitrification activity, we also want to determine the long-term denitrification potential which is governed by the stock of reactive material within these sediments. Here we present the first results of these long-term incubation experiments to investigate the stock of reactive material present in these sediments and its denitrification activity. In these batch experiments we filled the aquifer material from different depths between two and 68 m below ground in glass bottles, supplemented it with K15NO3 solution, sealed the bottles airtight with rubber septa and flushed the headspace with pure N2. Afterward the bottles where stored in the dark by 10° C to obtain aquifer like conditions. The labeled

  14. Role of macrofauna on benthic oxygen consumption in sandy sediments of a high-energy tidal beach

    NASA Astrophysics Data System (ADS)

    Charbonnier, Céline; Lavesque, Nicolas; Anschutz, Pierre; Bachelet, Guy; Lecroart, Pascal

    2016-06-01

    Sandy beaches exposed to tide and waves are characterized by low abundance and diversity of benthic macrofauna, because of high-energy conditions. This is the reason why there are few studies on benthic communities living in such highly dynamic environments. It has been shown recently that tidal sandy beaches may act as biogeochemical reactors. Marine organic matter that is supplied in the sand during each flood tide is efficiently mineralized through aerobic respiration. In order to quantify the role of macrofauna in the whole beach benthic respiration, we studied the macrofauna and the pore water oxygen content of an exposed sandy beach (Truc Vert, SW of France) during four seasons in 2011. The results showed that macrofauna was characterised by a low number of species of specialized organisms such as the crustaceans Eurydice naylori and Gastrosaccus spp. and the polychaetes Ophelia bicornis and Scolelepis squamata. The distribution and abundance of macrofauna were clearly affected by exposure degree and emersion time. The combined monitoring of benthic macrofauna and pore waters chemistry allowed us to estimate (1) the macrofauna oxygen uptake, calculated with a standard allometric relationship using biomass data, and (2) the total benthic oxygen uptake, calculated from the oxygen deficit measured in pore waters. This revealed that benthic macrofauna respiration represented a variable but low (<10%) contribution to the total benthic oxygen consumption. This suggests that oxygen was mainly consumed by microbial respiration.

  15. Assessing the impact of Hurricanes Irene and Sandy on the morphology and modern sediment thickness on the inner continental shelf offshore of Fire Island, New York

    USGS Publications Warehouse

    Schwab, William C.; Baldwin, Wayne E.; Denny, Jane F.

    2016-01-01

    This report documents the changes in seabed morphology and modern sediment thickness detected on the inner continental shelf offshore of Fire Island, New York, before and after Hurricanes Irene and Sandy made landfall. Comparison of acoustic backscatter imagery, seismic-reflection profiles, and bathymetry collected in 2011 and in 2014 show that sedimentary structures and depositional patterns moved alongshore to the southwest in water depths up to 30 meters during the 3-year period. The measured lateral offset distances range between about 1 and 450 meters with a mean of 20 meters. The mean distances computed indicate that change tended to decrease with increasing water depth. Comparison of isopach maps of modern sediment thickness show that a series of shoreface-attached sand ridges, which are the dominant sedimentary structures offshore of Fire Island, migrated toward the southwest because of erosion of the ridge crests and northeast-facing flanks as well as deposition on the southwest-facing flanks and in troughs between individual ridges. Statistics computed suggest that the modern sediment volume across the about 81 square kilometers of common sea floor mapped in both surveys decreased by 2.8 million cubic meters, which is a mean change of –0.03 meters, which is smaller than the resolution limit of the mapping systems used.

  16. A three-year time series of elemental and biochemical composition of organic matter in subtidal sandy sediments of the Ligurian Sea (northwestern Mediterranean)

    NASA Astrophysics Data System (ADS)

    Fabiano, M.; Danovaro, R.; Fraschetti, S.

    Variations in organic matter composition and microphytobenthic biomass were examined in the surface sandy sediments at a water depth of 10 m in the Gulf of Marconi (NW Mediterranean Sea) over a three year period. Seasonal changes in elemental (organic C and total N) and biochemical (lipids, proteins, carbohydrates) composition of sediment organic matter as well as Chla were assessed in order to provide information about the origin and fate of sedimentary organic matter, the contribution of microphytobenthic biomass, seasonal and interannual variations of food quantity and quality, and factors related to food availability. Data obtained in this three-year study revealed that organic matter determined with a muffle furnace is clearly an overestimate of the organic content of the sediment and is thus of little significance for benthic ecologists studying community dynamics in relation to food availability. Labile organic matter, utilized to estimate the food potentially available for benthic consumers, accounted for only a small percentage (on average less than 10%) of total organic C. The highest labile fraction was observed in spring, whereas minima were recorded in winter. Analysis of elemental and biochemical composition of organic matter showed an inverse relationship between amount of organic matter and its potential availability to consumers; small quantities of high-quality organic matter were replaced by large quantities of refractory material. The labile portion was mostly microphytobenthic (65% of the labile carbon). Protein: carbohydrate ratios were low and confirmed the role of proteins as a potentially limiting factor for consumers. Significant differences in nutritional quality of the sediment organic matter were observed from year to year, changes due to the increase in specific labile compound content.

  17. Laboratory investigations on the role of sediment surface and ground water chemistry in transport of bacteria through a contaminated Sandy Aquifer

    USGS Publications Warehouse

    Scholl, M.A.; Harvey, R.W.

    1992-01-01

    The effects of pH and sediment surface characteristics on sorption of indigenous groundwater bacteria were determined using contaminated and uncontaminated aquifer material from Cape Cod, MA. Over the pH range of the aquifer (5-7), the extent of bacterial sorption onto sediment in uncontaminated groundwater was strongly pH-dependent, but relatively pH-insensitive in contaminated groundwater from the site. Bacterial sorption was also affected by the presence of oxyhydroxide coatings (iron, aluminum, and manganese). Surface coating effects were most pronounced in uncontaminated groundwater (pH 6.4 at 10??C). Desorption of attached bacteria (up to 14% of the total number of labeled cells added) occurred in both field and laboratory experiments upon adjustment of groundwater to pH 8. The dependence of bacterial sorption upon environmental conditions suggests that bacterial immobilization could change substantially over relatively short distances in contaminated, sandy aquifers and that effects caused by changes in groundwater geochemistry can be significant.

  18. Effects of bioturbation on the fate of oil in coastal sandy sediments--an in situ experiment.

    PubMed

    Timmermann, Karen; Banta, Gary T; Klinge, Lars; Andersen, Ole

    2011-03-01

    Effects of bioturbation by the common lugworm Arenicola marina on the fate of oil hydrocarbons (alkanes and PAHs) were studied in situ during a simulated oil spill in a shallow coastal area of Roskilde fjord, Denmark. The fate of selected oil compounds was monitored during 120 d using GC-MS and bioturbation activity (feces production and irrigation) was measured regularly during the experiment and used as input parameters in a mechanistic model describing the effects of A. marina on the transport and degradation of oil compounds in the sediment. The chemical analytical data and model results indicated that A. marina had profound and predictable effects on the distribution, degradation and preservation of oil and that the net effect depended on the initial distribution of oil. In sediment with an oil contaminated subsurface-layer A. marina buried the layer deeper in the sediment which clearly enhanced oil persistence. Conversely, A. marina stimulated both the physical removal and microbial degradation of oil compounds in uniformly oil contaminated sediments especially in deeper sediment layers (10-20 cm below the surface), whereas the fate of oil compounds deposited in surface layers (0-5 cm) mainly was affected by removal processes induced by wave actions and other bioturbating infauna such as Nereis diversicolor, Corophium volutator and Hydrobia spp. present in the experimental plots. PMID:21186046

  19. Hurricane Sandy

    Atmospheric Science Data Center

    2015-03-05

    ... over Hurricane Sandy as the storm approached the U.S. east coast on October 28, 2012. The image at left covers an area 250 miles (400 ... are readily apparent in the low-level winds off the eastern coast of Florida, with speeds exceeding 45 mph (20 meters per second). The ...

  20. Combined effects of dam removal and past sediment mining on a relatively large lowland sandy gravel bed river (Vienne River, France)

    NASA Astrophysics Data System (ADS)

    Ursache, Ovidiu; Rodrigues, Stephane; Bouchard, Jean-Pierre; Jugé, Philippe; Richard, Nina

    2014-05-01

    Dam removal is of growing interest for the management of sediment fluxes within fluvial basins, morphological evolution and ecological restoration of rivers. If dam removal experiments are now quite well documented for small streams located in the upstream parts of river networks, examples of lowland and relatively large rivers are still scarce. In this study we present a dam removal operation carried out on the Vienne River (France) to restore both sediment and biotic continuity. The Vienne River is 363 km in length. On its middle reaches the average slope is equal to 0.0003 m.m-1 and the average annual discharge is 195 m3.s-1 at the gauging station of Nouâtre. The river is characterized by a sinuous single channel of an average width of 150 m. The sediments are mainly made of a siliceous mixture of sands and gravels and were intensively mined between years 1930 and 1995's. In 1920, a 4 m height dam was built just downstream the confluence between the Vienne and Creuse Rivers triggering a total sediment deposition upstream of 900 000 m3 in 75 years. Hence, in 1998, the removal of the dam increased severely the sediment supply delivered to the Vienne River. The objective of this study is to understand and quantify the fluvial processes and morphological evolution on a reach of 50 km of the Vienne associated with the dam remova and the presence of ancient sand pits located along the riverbed. This study is based on field data collected during 7 surveys performed between 1998 and 2013. This large dataset focuses on bed geometry (detailed bathymetrical surveys), sediment grain size, and bedload fluxes measured using isokinetic samplers. It was combined with a 1D numerical model developed to assess flow dynamics and sediment transport capacity before and after dam removal. Results show that dam removal triggered both headward and progressive (near the dam) erosions and that discharges higher than 100 m3.s-1 were sufficient to erode the sandy sediments trapped by the

  1. Adsorption and desorption of arsenate on sandy sediments from contaminated and uncontaminated saturated zones: Kinetic and equilibrium modeling.

    PubMed

    Hafeznezami, Saeedreza; Zimmer-Faust, Amity G; Dunne, Aislinn; Tran, Tiffany; Yang, Chao; Lam, Jacquelyn R; Reynolds, Matthew D; Davis, James A; Jay, Jennifer A

    2016-08-01

    Application of empirical models to adsorption of contaminants on natural heterogeneous sorbents is often challenging due to the uncertainty associated with fitting experimental data and determining adjustable parameters. Sediment samples from contaminated and uncontaminated portions of a study site in Maine, USA were collected and investigated for adsorption of arsenate [As(V)]. Two kinetic models were used to describe the results of single solute batch adsorption experiments. Piecewise linear regression of data linearized to fit pseudo-first order kinetic model resulted in two distinct rates and a cutoff time point of 14-19 h delineating the biphasic behavior of solute adsorption. During the initial rapid adsorption stage, an average of 60-80% of the total adsorption took place. Pseudo-second order kinetic models provided the best fit to the experimental data (R(2) > 0.99) and were capable of describing the adsorption over the entire range of experiments. Both Langmuir and Freundlich isotherms provided reasonable fits to the adsorption data at equilibrium. Langmuir-derived maximum adsorption capacity (St) of the studied sediments ranged between 29 and 97 mg/kg increasing from contaminated to uncontaminated sites. Solid phase As content of the sediments ranged from 3.8 to 10 mg/kg and the As/Fe ratios were highest in the amorphous phase. High-pH desorption experiments resulted in a greater percentage of solid phase As released into solution from experimentally-loaded sediments than from the unaltered samples suggesting that As(V) adsorption takes place on different reversible and irreversible surface sites. PMID:27218893

  2. Using Small Subunit Ribosomal RNA to Follow Dark Incorporation of 14C-bicarbonate by Bacteria and Archaea in Sandy Sediment

    NASA Astrophysics Data System (ADS)

    MacGregor, B. J.; Musat, N.; Kuypers, M. M.

    2007-12-01

    Small subunit ribosomal RNA (SSU rRNA) and the genes encoding it have become the basis of modern microbial phylogeny, and of numerous methods for characterizing the composition of bacterial, archaeal, and even eukaryotic communities as they occur in nature. A limitation of this approach has been that phylogeny alone is not a reliable guide to physiology, particularly for groups with no close relatives in culture. We have been developing ways of using the SSU rRNA molecule itself to identify and (eventually) quantify the carbon sources incorporated by particular phylogenetic groups. This can be done by taking advantage of natural variations in carbon isotopic composition among growth substrates, or by following incorporation of 13C- or 14C-labeled compounds. 14C has the advantage that natural background levels are negligible. In the present study, our goal is to identify species responsible for non-photosynthetic CO2 incorporation in sandy sediments of the German Wadden Sea. Sediment cores collected from the Janssand sand flats were percolated with 14C-bicarbonate at in situ temperature for 36-38h in the dark, total RNA isolated, and domain-specific oligonucleotide probes used to capture bacterial and archaeal SSU rRNA. Total and/or captured RNA was separated by denaturing polyacrylamide gel electrophoresis, and 14C detected by phosphor imager, autoradiography, or beta imager. Detection was fastest and most sensitive with the beta imager. Both Bacteria and Archaea had incorporated label, suggesting both groups may harbor non-photosynthetic autotrophs. The next step will be to use more specific capture probes. We are currently working to separate the captured domain-specific SSU rRNA on non-denaturing gels, with detection by the high-resolution mode of the beta imager, so that individual species incorporating label can be identified by RT-PCR and sequencing of labeled bands.

  3. Laboratory application of laser grain-size analyzer in determining suspended sediment concentration

    NASA Astrophysics Data System (ADS)

    Liu, Xiao; Feng, Xiuli; Liu, Jie; Lin, Lin

    2014-06-01

    Suspended sediment concentration (SSC) is an important parameter in marine sedimentology. With the development of technology, many acoustic and optical devices, such as the Laser In-Situ Scattering and Transmissometry, have been designed to measure in situ SSC and grain size distribution. But due to fund or other restrictions, many experiments were only conducted in laboratory, using an indoor laser grain-size analyzer and gravimetric method to measure grain size distribution and concentration, respectively. In this study the laboratory experiment is simplified by omitting the tiring step of gravimetric method. The connections between SSC and other parameters (obscuration, D50 and sorting index) were investigated based on 124 surface sediment samples collected from different offshore areas. A new method is developed for determining SSC in laboratory using a laser grain-size analyzer.

  4. Degradation of dissolved organic monomers and short-chain fatty acids in sandy marine sediment by fermentation and sulfate reduction

    NASA Astrophysics Data System (ADS)

    Valdemarsen, Thomas; Kristensen, Erik

    2010-03-01

    The decay of a wide range of organic monomers (short-chain volatile fatty acids (VFA's), amino acids, glucose and a pyrimidine) was studied in marine sediments using experimental plug flow-through reactors. The reactions were followed in the presence and absence of 10 mM SO 42-. Degradation stoichiometry of individual monomers (inflow concentration of 6 mM organic C) was traced by measuring organic (VFA's, amino acids) and inorganic (CO 2, NH 4+, SO 42-) compounds in the outflow. Fermentation of amino acids was efficient and complete during passage through anoxic sediment reactors. Aliphatic amino acids (alanine, serine and glutamate) were primarily recovered as CO 2 (24-34%), formate (3-22%) and acetate (41-83%), whereas only ˜1/3 of the aromatic amino acid (tyrosine) was recovered as CO 2 (13%) and acetate (20%). Fermentation of glucose and cytosine was also efficient (78-86%) with CO 2 (30-35%), formate (3%) and acetate (28-33%) as the primary products. Fermentation of VFA's (acetate, propionate and butyrate), on the other hand, appeared to be product inhibited. The presence of SO 42- markedly stimulated VFA degradation (29-45% efficiency), and these compounds were recovered as CO 2 (17% for butyrate to 100% for acetate) and acetate (51% and 82% for propionate and butyrate, respectively). When reaction stoichiometry during fermentation is compared with compound depletion during sulfate reduction, the higher proportion CO 2 recovery is consistent with lower acetate and formate accumulation. Our results therefore suggest that fermentation reactions mediate the initial degradation of added organic compounds, even during active sulfate reduction. Fermentative degradation stoichiometry also suggested significant H 2 production, and >50% of sulfate reduction appeared to be fuelled by H 2. Furthermore, our results suggest that fermentation was the primary deamination step during degradation of the amino acids and cytosine.

  5. Functional structure of laminated microbial sediments from a supratidal sandy beach of the German Wadden Sea (St. Peter-Ording)

    NASA Astrophysics Data System (ADS)

    Bühring, Solveig I.; Kamp, Anja; Wörmer, Lars; Ho, Stephanie; Hinrichs, Kai-Uwe

    2014-01-01

    Hidden for the untrained eye through a thin layer of sand, laminated microbial sediments occur in supratidal beaches along the North Sea coast. The inhabiting microbial communities organize themselves in response to vertical gradients of light, oxygen or sulfur compounds. We performed a fine-scale investigation on the vertical zonation of the microbial communities using a lipid biomarker approach, and assessed the biogeochemical processes using a combination of microsensor measurements and a 13C-labeling experiment. Lipid biomarker fingerprinting showed the overarching importance of cyanobacteria and diatoms in these systems, and heterocyst glycolipids revealed the presence of diazotrophic cyanobacteria even in 9 to 20 mm depth. High abundance of ornithine lipids (OL) throughout the system may derive from sulfate reducing bacteria, while a characteristic OL profile between 5 and 8 mm may indicate presence of purple non-sulfur bacteria. The fate of 13C-labeled bicarbonate was followed by experimentally investigating the uptake into microbial lipids, revealing an overarching importance of cyanobacteria for carbon fixation. However, in deeper layers, uptake into purple sulfur bacteria was evident, and a close microbial coupling could be shown by uptake of label into lipids of sulfate reducing bacteria in the deepest layer. Microsensor measurements in sediment cores collected at a later time point revealed the same general pattern as the biomarker analysis and the labeling experiments. Oxygen and pH-microsensor profiles showed active photosynthesis in the top layer. The sulfide that diffuses from deeper down and decreases just below the layer of active oxygenic photosynthesis indicates the presence of sulfur bacteria, like anoxygenic phototrophs that use sulfide instead of water for photosynthesis.

  6. An experimental challenge: Unraveling the dependencies of ultrasonic and electrical properties of sandy sediments with pore-filling gas hydrates

    NASA Astrophysics Data System (ADS)

    Heeschen, Katja; Spangenberg, Erik; Seyberth, Karl; Priegnitz, Mike; Schicks, Judith M.

    2016-04-01

    The accuracy of gas hydrate quantification using seismic or electric measurements fundamentally depends on the knowledge of any factor describing the dependencies of physical properties on gas hydrate saturation. Commonly, these correlations are the result of laboratory measurements on artificially produced gas hydrates of exact saturation. Thus, the production of gas hydrates and accurate determination of gas hydrate concentrations or those of a substitute are a major concern. Here we present data of both, seismic and electric measurements on accurately quantified pore-filling ice as a substitute for natural gas hydrates. The method was validated using selected gas hydrate saturations in the same experimental set-up as well as literature data from glass bead samples [Spangenberg and Kulenkampff, 2006]. The environmental parameters were chosen to fit those of a possible gas hydrate reservoir in the Danube Delta, which is in the focus of models for joint inversions of seismic and electromagnetic data in the SUGAR III project. The small effective pressures present at this site proved to be yet another challenge for the experiments. Using a more powerful pulse generator and a 4 electrode electric measurement, respectively, models for a wide range of gas hydrate saturations between 20 - 90 % vol. could be established. Spangenberg, E. and Kulenkampff, J., Influence of methane hydrate content on electrical sediment properties. Geophysical Research Letters 2006, 33, (24).

  7. Composition of conglomerates analyzed by the Curiosity rover: Implications for Gale Crater crust and sediment sources

    NASA Astrophysics Data System (ADS)

    Mangold, N.; Thompson, L. M.; Forni, O.; Williams, A. J.; Fabre, C.; Le Deit, L.; Wiens, R. C.; Williams, R.; Anderson, R. B.; Blaney, D. L.; Calef, F.; Cousin, A.; Clegg, S. M.; Dromart, G.; Dietrich, W. E.; Edgett, K. S.; Fisk, M. R.; Gasnault, O.; Gellert, R.; Grotzinger, J. P.; Kah, L.; Le Mouélic, S.; McLennan, S. M.; Maurice, S.; Meslin, P.-Y.; Newsom, H. E.; Palucis, M. C.; Rapin, W.; Sautter, V.; Siebach, K. L.; Stack, K.; Sumner, D.; Yingst, A.

    2016-03-01

    The Curiosity rover has analyzed various detrital sedimentary rocks at Gale Crater, among which fluvial and lacustrine rocks are predominant. Conglomerates correspond both to the coarsest sediments analyzed and the least modified by chemical alteration, enabling us to link their chemistry to that of source rocks on the Gale Crater rims. In this study, we report the results of six conglomerate targets analyzed by Alpha-Particle X-ray Spectrometer and 40 analyzed by ChemCam. The bulk chemistry derived by both instruments suggests two distinct end-members for the conglomerate compositions. The first group (Darwin type) is typical of conglomerates analyzed before sol 540; it has a felsic alkali-rich composition, with a Na2O/K2O > 5. The second group (Kimberley type) is typical of conglomerates analyzed between sols 540 and 670 in the vicinity of the Kimberley waypoint; it has an alkali-rich potassic composition with Na2O/K2O < 2. The variety of chemistry and igneous textures (when identifiable) of individual clasts suggest that each conglomerate type is a mixture of multiple source rocks. Conglomerate compositions are in agreement with most of the felsic alkali-rich float rock compositions analyzed in the hummocky plains. The average composition of conglomerates can be taken as a proxy of the average igneous crust composition at Gale Crater. Differences between the composition of conglomerates and that of finer-grained detrital sediments analyzed by the rover suggest modifications by diagenetic processes (especially for Mg enrichments in fine-grained rocks), physical sorting, and mixing with finer-grained material of different composition.

  8. Analyzing sediment impacts for the Glen Canyon Long-term Experimental and Management Plan EIS

    NASA Astrophysics Data System (ADS)

    Russell, K.; Huang, V.; Varyu, D.; Greimann, B. P.; O'Connor, B. L.

    2013-12-01

    The Department of the Interior is currently evaluating alternatives in the Glen Canyon Dam Long-term Experimental and Management Plan (LTEMP) Environmental Impact Statement (EIS). The purpose of the EIS to evaluate dam operations and identify management actions and experimental options that will provide a framework for adaptively managing operations of Glen Canyon Dam over the next 15 to 20 years. Sediment and sandbars along the Colorado River are important downstream resources in Grand Canyon National Park. Sediment is one of the resources being analyzed for impacts in Marble and Grand Canyon. Since 1963, Glen Canyon Dam has regulated the flow in the Colorado River by decreasing the magnitude of annual flood flows and increasing the magnitude of base flows, and has nearly eliminated main-channel sand supply from the upper Colorado River Basin. These changes disrupted the natural ability of the river to build and maintain sandbars. Grand Canyon sandbars provide camping beaches for river runners and hikers, generate habitat for native fish and vegetation, and supply sediment to protect archaeological resources. In order to measure the impacts of the different alternatives on the sediment resource, several different models are being utilized. A sand budget numerical model that tracks the storage and transport of sand in the Colorado River below Glen Canyon Dam developed by the USGS is utilized. The model uses empirically based rating curves for specific particle sizes. The decision criteria for the high flow experiment environmental assessment is applied to the sand budget model as well as other flow changes incorporated in the alternatives. An empirically based sandbar volume model was also developed for the LTEMP EIS process to address the sandbar resource impacts. Based on the model results, performance criteria have been established to allow for comparisons between the alternatives. The criteria include the changes in the sand mass balance of the system, the

  9. Development of a Numerical Simulator for Analyzing the Geomechanical Performance of Hydrate-Bearing Sediments

    SciTech Connect

    Rutqvist, Jonny; Rutqvist, J.; Moridis, G.J.

    2008-06-01

    In this paper, we describe the development and application of a numerical simulator that analyzes the geomechanical performance of hydrate-bearing sediments, which may become an important future energy supply. The simulator is developed by coupling a robust numerical simulator of coupled fluid flow, hydrate thermodynamics, and phase behavior in geologic media (TOUGH+HYDRATE) with an established geomechanical code (FLAC3D). We demonstrate the current simulator capabilities and applicability for two examples of geomechanical responses of hydrate bearing sediments during production-induced hydrate dissociation. In these applications, the coupled geomechanical behavior within hydrate-bearing seducements are considered through a Mohr-Coulomb constitutive model, corrected for changes in pore-filling hydrate and ice content, based on laboratory data. The results demonstrate how depressurization-based gas production from oceanic hydrate deposits may lead to severe geomechanical problems unless care is taken in designing the production scheme. We conclude that the coupled simulator can be used to design production strategies for optimizing production, while avoiding damaging geomechanical problems.

  10. Dynamic changes of sandy land in northwest of Beijing, China.

    PubMed

    Wang, Jing; He, Ting; Guo, Xudong; Liu, Aixia; Zhou, Qing

    2006-10-01

    The area northwest of Beijing is one of the most important regions where many organizations invest and pay most attention. The environmental problems in this region affect not only Beijing but also the surrounding area. Based on observation of the characteristics of the change in sandy land, this study classified four types of dynamic change of sandy land, including extended sandy land, the reversely changed sandy land, the potential sandy land and no change in sandy land. Then the process and the trend of changes in sandy land and their environmental impact on the area northwest of Beijing were analyzed. The results show that the area of sandy land has increased in this region in the period of 1991 to 2002. Change between sandy land and grassland was the dominant change. It is found that the monitoring zones of Hunshandake sandy land and north of Yin Shan are regions with high ratio of extended sandy land, and are connected with widespread potential change of sandy land. This implies that these two regions have a high probability of increase in sandy land in the future. On the other hand, in the monitoring zone of Horqin sandy land and Ba Shang Plateau and its surrounding area, desertification had been controlled and the area of sandy land is expected to decrease. This indicates that the direction of the sandstorm to Beijing is expected to gradually move to the northwest. Furthermore, the decreases in sandy land and the reversing change from arable land to grassland and forests in the study region will affect the land quality and atmosphere. And the logistic multiple regression (LMR) model was employed to better understand the complexity and processes of increases in sandy land. This model predicts that there is a high probability of increases in sandy land in north of Siziwang Banner, Zhengxiangbai Banner and Zhenglan Banner. Finally, suggestions to the ecological construction of the study area have been proposed. PMID:16758285

  11. AnalySize: New software for analyzing and unmixing sediment grain size distribution spectra

    NASA Astrophysics Data System (ADS)

    Paterson, G. A.; Heslop, D.

    2015-12-01

    Grain size distribution (GSD) data are a widely used tool in Earth sciences, particularly in understanding sediment transportation and sourcing. Although large data sets are regularly generated, detailed numerical analyses, such as grain size unmixing, are not routinely performed. Unmixing of GSD data involves approximating a given data set by a small number of GSDs, known as end members. These end members, along with their relative abundances, can be used to fully characterize the variability of the data. End member analysis (EMA), which fits one set of end members to a single data set, is one the most robust ways to do this. This approach estimates the form of the end members from the data set itself; hence it is a non-parametric approach. Available algorithms, however, either produce sub-optimal solutions, or are time consuming. To aid investigators in exploring the full potential of their data, we introduce AnalySize, which is a GUI based tool that allows for comprehensive processing and unmixing of grain size data obtained from laser diffraction particle grain size analyzers. AnalySize brings together methods from other disciplines in Earth sciences as well as introducing new techniques and improvements to provide a complete software package for unmixing GSD data. The software utilizes the rapid HALS-NMF algorithm from hyperspectral image analysis to perform non-parametric EMA, which is demonstrated to yield results that are an improvement over algorithms currently used in GSD analysis. Non-parametric EMA, however, is often unable to clearly identify discrete unimodal grain size sub-populations, which can more detailed information about sediment sources. To alleviate this, we introduce a new algorithm to perform parametric EMA, whereby an entire GSD data set can be unmixed into unimodal parametric end members (e.g., lognormal or Weibull end members). This allows individual grain size sub-populations to be more readily identifiable in highly mixed data set

  12. Analyzing the contribution of climate change to long-term variations in sediment nitrogen sources for reservoirs/lakes.

    PubMed

    Xia, Xinghui; Wu, Qiong; Zhu, Baotong; Zhao, Pujun; Zhang, Shangwei; Yang, Lingyan

    2015-08-01

    We applied a mixing model based on stable isotopic δ(13)C, δ(15)N, and C:N ratios to estimate the contributions of multiple sources to sediment nitrogen. We also developed a conceptual model describing and analyzing the impacts of climate change on nitrogen enrichment. These two models were conducted in Miyun Reservoir to analyze the contribution of climate change to the variations in sediment nitrogen sources based on two (210)Pb and (137)Cs dated sediment cores. The results showed that during the past 50years, average contributions of soil and fertilizer, submerged macrophytes, N2-fixing phytoplankton, and non-N2-fixing phytoplankton were 40.7%, 40.3%, 11.8%, and 7.2%, respectively. In addition, total nitrogen (TN) contents in sediment showed significant increasing trends from 1960 to 2010, and sediment nitrogen of both submerged macrophytes and phytoplankton sources exhibited significant increasing trends during the past 50years. In contrast, soil and fertilizer sources showed a significant decreasing trend from 1990 to 2010. According to the changing trend of N2-fixing phytoplankton, changes of temperature and sunshine duration accounted for at least 43% of the trend in the sediment nitrogen enrichment over the past 50years. Regression analysis of the climatic factors on nitrogen sources showed that the contributions of precipitation, temperature, and sunshine duration to the variations in sediment nitrogen sources ranged from 18.5% to 60.3%. The study demonstrates that the mixing model provides a robust method for calculating the contribution of multiple nitrogen sources in sediment, and this study also suggests that N2-fixing phytoplankton could be regarded as an important response factor for assessing the impacts of climate change on nitrogen enrichment. PMID:25862992

  13. Analyzing microbial and sediment geochemistry to identify safe aquifer zones in an Arsenic prone aquifer

    NASA Astrophysics Data System (ADS)

    Kibria, G.; Hossain, M.; Kirk, M. F.; Bhattacharya, P.; Ahmed, K.; Datta, S.

    2013-12-01

    The assessment of the incidence of arsenic (As) and other oxyanions was examined in Bengal delta floodplain groundwaters from Matlab Upazila, Bangladesh. Our field campaign in 2013 covered an area of ~400km2 between North and South Matlab. Shallow tubewells except those installed within off-white sediments are mostly contaminated with high As. In our field studies we found the wells installed within light grey medium sand, the As concentration was found below 50μg/L. Groundwater abstracted from oxidized reddish sediments in contrast to reduced greyish sediments, contain significantly lower amount of dissolved As and can be a source of safe water. Sediment geochemistry and adsorption extent of oxidized red brown and reduced grey sediments to attenuate As are studied here. Sediment cores were collected at regular intervals from within depth of ~125m in Matlab. This study describes the color, lithofacies and mineralogy of the sediments The stable isotopes of groundwaters from various depths within a piezometer nest are studied also to determine the extent of hydraulic conductivity between depths of aquifers along with mechanism of recharge of the groundwater at those depths. DNA recovered from Matlab core samples averaged 450ng/g from course-grained samples and 800ng/g from fine-grained samples. After sequencing the DNA, it was found that microbial community in red or light gray sediments are different than gray-dark gray sediments (e.g. Burkholderiaceae and Pseudomonadacee are common in grey/ dark gray sediment but Streptomycetaceae is common in red/ light grey color). Rhodocyclaceae, Aeromonadaceae, Shewanellaceae are the common genera present in these sediments that are capable of reducing Fe in this aquifer environment. Synchrotron aided μXANES and μXRD studies conducted for solid state As and S speciation in the core samples at different depths indicate the occurrences of hotspots of As differently distributed in red-brown and grey sediments. Samples collected

  14. Numerical model for analyzing the effects of sediment supply on river morphology and streambed characteristics

    NASA Astrophysics Data System (ADS)

    Tonina, D.; McKean, J. A.; Buffington, J. M.; Luce, C.; Dietrich, W. E.

    2007-12-01

    We are investigating the effects of different sediment supply regimes on the morphology and aquatic habitat of gravel-bed rivers in mountain basins. Sediment inputs to the river network in these environments range from periodic pulsed events of large magnitude (e.g., landslides and debris flows) to low-level chronic inputs (e.g., road drainage). The pulsed events tend to be natural, while the chronic inputs are commonly anthropogenic. Our goal is to inform managers of the range of sediment supply impacts and to evaluate the common perception that pulsed events are more detrimental to the aquatic ecosystem. Four cases of sediment supply are considered: 1) periodic pulses of fine material (e.g., debris flows in decomposed granite), 2) periodic pulses of coarse material (e.g., landslides in harder bedrock), 3) chronic supplies of fine material (e.g., roads or distributed soil creep and dry raveling) and 4) chronic supplies of coarse material (e.g., mining activity). Currently we are focusing on fine sediment moving primarily as bedload at flows below bank-full over an immobile coarse-grained bed. As part of this work, we evaluated the performance of available surface-based transport models. Predicted transport rates were compared to field measurements from gravel-bed rivers in Idaho. Results show that the Wilcock and Kenworthy (2002) equation performs best. We also have developed a sand conservation model based on filling the voids between coarse particles in a gravel bed. Numerical simulations were conducted coupling the conservation model with the Wilcock and Kenworthy equation using an extension of the MD-SWMS hydraulic model (McDonald et al. 2005). Performance of the transport and conservation models has been tested with data from laboratory experiments. Future modeling will initially compare the effects of cases 1) and 2) (chronic versus pulsed loads of fine sediment), as smaller particles are often implicated in degradation of aquatic habitats.

  15. Analyzing the uncertainty of suspended sediment load prediction using sequential data assimilation

    NASA Astrophysics Data System (ADS)

    Leisenring, Marc; Moradkhani, Hamid

    2012-10-01

    SummaryA first step in understanding the impacts of sediment and controlling the sources of sediment is to quantify the mass loading. Since mass loading is the product of flow and concentration, the quantification of loads first requires the quantification of runoff volume. Using the National Weather Service's SNOW-17 and the Sacramento Soil Moisture Accounting (SAC-SMA) models, this study employed particle filter based Bayesian data assimilation methods to predict seasonal snow water equivalent (SWE) and runoff within a small watershed in the Lake Tahoe Basin located in California, USA. A procedure was developed to scale the variance multipliers (a.k.a hyperparameters) for model parameters and predictions based on the accuracy of the mean predictions relative to the ensemble spread. In addition, an online bias correction algorithm based on the lagged average bias was implemented to detect and correct for systematic bias in model forecasts prior to updating with the particle filter. Both of these methods significantly improved the performance of the particle filter without requiring excessively wide prediction bounds. The flow ensemble was linked to a non-linear regression model that was used to predict suspended sediment concentrations (SSCs) based on runoff rate and time of year. Runoff volumes and SSC were then combined to produce an ensemble of suspended sediment load estimates. Annual suspended sediment loads for the 5 years of simulation were finally computed along with 95% prediction intervals that account for uncertainty in both the SSC regression model and flow rate estimates. Understanding the uncertainty associated with annual suspended sediment load predictions is critical for making sound watershed management decisions aimed at maintaining the exceptional clarity of Lake Tahoe. The computational methods developed and applied in this research could assist with similar studies where it is important to quantify the predictive uncertainty of pollutant load

  16. Seismic tracking of Hurricane Sandy

    NASA Astrophysics Data System (ADS)

    Chen, X.; Wen, L.

    2013-12-01

    Very weak, narrow band seismic signals excited by Hurricane Sandy are detected in cross-correlations of continuous waveforms recorded by stations in eastern United States, at the end of October 2012. We analyze propagational properties of the signal and track the source locations using travel-time difference residual projection, from 26 October to 1 November 2012. We find that (1) the seismic signals driven by Hurricane Sandy are azimuthal dependent. Signals are correlated only within close azimuths from the source, (2) seismic signals propagate as Rayleigh surface wave with an average velocity of about 3.3 km/s, and (3) the inferred seismic source locations follow the path of Sandy before UTC 2012.10.30 12:00:00(about half a day after its landfall in New Jersey), but then deviate from the hurricane center and stay in the coastal area near New England for another 12 hours after the hurricane dissipated. Our research discovers the properties of seismic source excited by Hurricane Sandy and demonstrates the capability of using seismic data to real-time track a hurricane and estimate its direct impacts and the subsequent disasters after it dissipates.

  17. Structure analysis of shallow water ecosystems: Interaction of microbiological, chemical and physical characteristics measured in the overlying waters of sandy beach sediments

    NASA Astrophysics Data System (ADS)

    Bölter, Manfred; Meyer-Reil, Lutz-Arend; Rodger, Dawson; Gerd, Liebezeit; Karin, Wolter; Heidrun, Szwerinki

    1981-11-01

    An ecological study of the shallow, brackish water ecosystem near sandy beaches in the Kiel Fjord and Kiel Bight (Western Baltic Sea) was carried out in July 1977. A total of 33 parameters describing physical, chemical and biological characteristics were processed with particular reference to microbiological activity. The data were compared by a rank correlation analysis which revealed a large variety of relationships, the interpretation of which permitted a comprehensive description of the ecosystem. It could be shown that certain parameters occupy a central position in the correlation pattern. Such parameters are salinity, nitrite, particulate organic carbon and nitrogen, free dissolved glucose and ribose, bacterial biomass, filamentous cells and biological oxygen demand. The use of such a correlation pattern in providing a general description of the shallow water ecosystem is discussed, taking into account the results of earlier investigations in this region.

  18. Measuring Dissolved Oxygen Quantitatively. Collecting and Cultivating Marine Bacteria. To Recognize, Record, and Analyze Characteristics of a Sandy Beach Environment. Quantitative and Qualitative Analysis of Phosphate in Water. Learning Experiences for Coastal and Oceanic Awareness Studies, Nos. 307, 309, 310, 313. [Project COAST].

    ERIC Educational Resources Information Center

    Delaware Univ., Newark. Coll. of Education.

    Included are four activity units: (1) Measuring Dissolved Oxygen Quantitatively; (2) Collecting and Cultivating Marine Bacteria; (3) To Recognize, Record, and Analyze Characteristics of a Sandy Beach Environment; and (4) Quantitative and Qualitative Analysis of Phosphate in Water. All the activities are designed to be used by secondary school…

  19. Sediment Transport and Infilling of a Borrow Pit on an Energetic Sandy Ebb Tidal Delta Offshore of Hilton Head Island, South Carolina

    NASA Astrophysics Data System (ADS)

    Wren, A.; Xu, K.; Ma, Y.; Sanger, D.; Van Dolah, R.

    2014-12-01

    Bottom-mounted instrumentation was deployed at two sites on an ebb tidal delta to measure hydrodynamics, sediment transport, and seabed elevation. One site ('borrow site') was 2 km offshore and used as a dredging site for beach nourishment of nearby Hilton Head Island in South Carolina, and the other site ('reference site') was 10 km offshore and not directly impacted by the dredging. In-situ time-series data were collected during two periods after the dredging: March 15 - June 12, 2012('spring') and August 18 - November 18, 2012 ('fall'). At the reference site directional wave spectra and upper water column current velocities were measured, as well as high-resolution current velocity profiles and suspended sediment concentration profiles in the Bottom Boundary Layer (BBL). Seabed elevation and small-scale seabed changes were also measured. At the borrow site seabed elevation and near-bed wave and current velocities were collected using an Acoustic Doppler Velocimeter. Throughout both deployments bottom wave orbital velocities ranged from 0 - 110 m/s at the reference site. Wave orbital velocities were much lower at the borrow site ranging from 10-20 cm/s, as wave energy was dissipated on the extensive and rough sand banks before reaching the borrow site. Suspended sediment concentrations increased throughout the BBL when orbital velocities increased to approximately 20 cm/s. Sediment grain size and critical shear stresses were similar at both sites, therefore, re-suspension due to waves was less frequent at the borrow site. However, sediment concentrations were highly correlated with the tidal cycle at both sites. Semidiurnal tidal currents were similar at the two sites, typically ranging from 0 - 50 cm/s in the BBL. Maximum currents exceeded the critical shear stress and measured suspended sediment concentrations increased during the first hours of the tidal cycle when the tide switched to flood tide. Results indicate waves contributed more to sediment mobility at

  20. Sandy desertification cycles in the southwestern Mu Us Desert in China over the past 80 years recorded based on nebkha sediments

    NASA Astrophysics Data System (ADS)

    Li, Jinchang; Zhao, Yanfang; Liu, Haixia; Su, Zhizhu

    2016-03-01

    Sandy desertification (SDN) cycles in the southwestern Mu Us Desert since the late 1920s were recorded based on the evolution of Nitraria tangutorum nebkhas. Particle size changes of the nebkha excavated during the study, together with AMS 14C and 137Cs dating controls, indicated that the SDN of the study area was reverse on the whole over the past 80 years, but multiple SDN cycles also occurred. SDN mainly occurred during the late 1920s to the early 1940s, late 1940s to early 1950s, late 1950s to early 1960s, mid- and late 1980s, and early 2000s. The formation of nebkhas in the study area was triggered by severe SDN caused by extreme drought events that occurred in the 1920s to the 1930s. Over the past 80 years, the general SDN trend in the southwestern Mu Us Desert was mainly controlled by the westerly circulation strength, and severe SDN resulted mainly from extreme drought events in a large spatial scale, whereas slight SDN cycles were mainly due to local climate fluctuations and human activities.

  1. Experimental study of interactions between purple and green sulfur bacteria in sandy sediments exposed to illumination deprived of near-infrared wavelengths.

    PubMed

    Massé, Astrid; Pringault, Olivier; De Wit, Rutger

    2002-06-01

    Sedimentary biofilms of the green sulfur bacterium Prosthecochloris aestuarii strain CE 2404, the purple sulfur bacterium Thiocapsa roseopersicina strain 5811, and a mixed culture of both were cultured in fine sand (100- to 300-microm grain size) within counter gradients of oxygen and sulfide. The artificial sediments were exposed to illumination deprived of near-infrared light (NIR) by filtering out the wavelengths longer than 700 nm to simulate the critical light conditions in submerged aquatic sediments. A 16 h of visible light-8 h of dark regimen was used. We studied the effects of these light conditions on the metabolisms of and interactions between both species by comparing the single species biofilms with the mixed biofilm. The photosynthesis rates of P. aestuarii were shown to be highly limited by the imposed light conditions, because the sulfide photooxidation rates were strongly stimulated when NIR was added. T. roseopersicina performed both aerobic chemosynthesis and photosynthesis, but the photosynthesis rates were low and poorly stimulated by the addition of NIR. This species decreased the penetration depth of oxygen in the sediment by about 1 mm by actively respiring oxygen. This way, the strict anaerobe P. aestuarii was able to grow closer to the surface in the mixed culture. As a result, P. aestuarii benefited from the presence of T. roseopersicina in the mixed culture, which was reflected by an increase in the biomass. In contrast, the density of the latter species was almost completely unaffected by the interaction. Both species coexisted in a layer of the same depth in the mixed culture, and the ecological and evolutionary implications of coexistence are discussed. PMID:12039757

  2. Influence of waves and horseshoe crab spawning on beach morphology and sediment grain-size characteristics on a sandy estuarine beach

    USGS Publications Warehouse

    Jackson, N.L.; Nordstrom, K.F.; Smith, D.R.

    2005-01-01

    The effects of wave action and horseshoe crab spawning on the topography and grain-size characteristics on the foreshore of an estuarine sand beach in Delaware Bay, New Jersey, USA were evaluated using data collected over six consecutive high tides. Data were gathered inside and outside a 25 m long exclosure constructed to create a control area free of disturbance by crabs. The density of crabs in the swash zone outside the exclosure was 8??1 organisms m-2. The maximum depth of sediment activation on the upper foreshore where spawning occurred was 0??103 m during periods characterized by low significant wave heights: < 0??08 m. This depth is greater than the depth of activation by waves alone during moderate significant wave heights of 0??16 - 0??18 m but less than the maximum depth (0??127 m) recorded when spawning occurred during periods of moderate wave heights. Spawning, combined with moderate wave heights, creates a concave upper foreshore that is similar to the type of profile change that occurs during storms, thus lowering the wave-energy threshold for morphological response. Spawning during low wave heights increases the mean grain size and sorting of surface sediments caused by the addition of gravel to the swash. Sedimentological differences are most pronounced on the upper foreshore, and data from this location may be most useful when using grain-size characteristics to interpret the effect of spawning in the sedimentary record. Depths of sediment reworking by horseshoe crabs can be greater than those by subsequent storm waves, so evidence of spawning can be preserved on non-eroding beaches. Greater depth of activation by horseshoe crab spawning than by waves alone, even during moderate-energy conditions, reveals the importance of crab burrowing in releasing eggs to the water column and making them available for shore birds. ?? 2005 International Association of Sedimentologists.

  3. Maps showing bathymetry and modern sediment thickness on the inner continental shelf offshore of Fire Island, New York, pre-Hurricane Sandy

    USGS Publications Warehouse

    Schwab, William C.; Denny, Jane F.; Baldwin, Wayne E.

    2014-01-01

    The U.S. Geological Survey mapped approximately 336 square kilometers of the lower shoreface and inner continental shelf offshore of Fire Island, New York, in 2011 by using interferometric sonar and high-resolution chirp seismic-reflection systems. This report presents maps of bathymetry, acoustic backscatter, the coastal plain unconformity, the Holocene marine transgressive surface, and modern sediment thickness. These spatial data support research on the Quaternary evolution of the Fire Island coastal system and provide baseline information for research on coastal processes along southern Long Island.

  4. Accretion process of sediments below Kumano basin by analyzing cuttings from IODP Exp.319, the first riser drilling

    NASA Astrophysics Data System (ADS)

    Kawabata, K.; Sakaguchi, A.; Kitamura, Y.; Saito, S.

    2012-12-01

    The structure, stress condition and rock properties of accreted sediments in the Nankai Trough have been studied by reflection seismology and deep sea drillings. Accretion processes have been suggested by onland geological studies that the sediments are circulated with undergoing lithification and deformation along thrusts in shallow subduction zone driven by the plate motion. However the process in the modern Nankai Trough has yet to be elucidated. We discuss the accretion process of the shallow Nankai Trough accretionary prism below Kumano basin by clarifying thermal structure and materials by vitrinite measurement and whole rock chemical analyses, respectively, using cuttings samples from IODP The Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) the first scientific riser drilling Expedition 319 at Site C0009. Cuttings were collected with an interval of every 5 m from 703.9 to 1604 m and cores were recovered from 1509.7 m to 1593.9 m below sea floor (mbsf). Due to poor consolidation of drilled sediments, cuttings samples typically consist of sand and silt floating in a matrix of mixed sedimentary and drilling muds, and solid rock chips were not retrieved above 802.7 mbsf. Visual description based on macro- and micro-scopic observation, XRD and XRF analysis, rocks properties and the age of washed cuttings (i.e. grains without mud) were made throughout the hole, which allowed to establish some indexes to estimate lithology. Four lithologic units (Unit I - IV) were defined at Site C0009 based on compositional and textural variations of cuttings samples, which are believed to closely reflect lithologic changes of drilled sequences, and show good consistency with logging data. Unit IV is believed to be accreted sediment by mainly age and the textural change of sediments. Dissoluble component ratios (TiO2/P2O5) and clay content ratios in the samples analyzed by XRF and XRD are different from that in basin sediment, which might support Unit IV are accreted

  5. Paleosols can promote root growth of the recent vegetation - a case study from the sandy soil-sediment sequence Rakt, the Netherlands

    NASA Astrophysics Data System (ADS)

    Gocke, M. I.; Kessler, F.; van Mourik, J. M.; Jansen, B.; Wiesenberg, G. L. B.

    2015-12-01

    Soil studies commonly comprise the uppermost meter for tracing e.g. soil development. However, the maximum rooting depth of various plants significantly exceeds this depth. We hypothesized that deeper parts of the soil, soil parent material and especially paleosols provide beneficial conditions in terms of e.g. nutrient contents, thus supporting their utilization and exploitation by deep roots. We aimed to decipher the different phases of soil formation in Dutch drift- and coversands. The study site is located at Bedafse Bergen (SE Netherlands) in a 200 year old oak stand. A recent Podzol developed on driftsand covering a Plaggic Anthrosol that established in a relict Podzol on Late Glacial eolian coversand. Root-free soil and sediment samples, collected in 10-15 cm depth increments, were subjected to a multi-proxy physical and geochemical approach. The Plaggic Anthrosol revealed low bulk density and high phosphorous and organic carbon contents, whereas the relict Podzol was characterized by high iron and aluminum contents. Frequencies of fine (≤ 2 mm) and medium roots (2-5 mm) were determined on horizontal levels and the profile wall for a detailed pseudo-three-dimensional insight. On horizontal levels, living roots maximized in the uppermost part of the relict Podzol with ca. 4450 and 220 m-2, significantly exceeding topsoil root abundances. Roots of oak trees thus benefited from the favorable growth conditions in the nutrient-rich Plaggic Anthrosol, whereas increased compactness and high aluminum contents of the relict Podzol caused a strong decrease of roots. The approach demonstrated the benefit of comprehensive root investigation to support and explain pedogenic investigations of soil profiles, as fine roots can be significantly underestimated when quantified at the profile wall. The possible rooting of soil parent material and paleosols long after their burial confirmed recent studies on the potential influence of rooting to overprint sediment

  6. Analytical data and sample locality map for aqua-regia leachates of stream sediments analyzed by ICP from the Chignik and Sutwik Island quadrangles, Alaska

    SciTech Connect

    Van Trump, G. Jr.; Motooka, J.M.; Erlich, O.; Tompkins, M.L.

    1989-01-01

    A U.S. Geological report is presented detailing analytical data and sample locality map for aqua-regia leachates of stream sediments analyzed by ICP from the Chignik and Sutwik Island quadrangles, Alaska.

  7. Analytical data and sample locality map for aqua-regia leachates of stream sediments analyzed by ICP, and emission spectrographic results for both stream sediments and panned concentrates collected in 1985 from the Chandler Lake Quadrangle, Alaska

    SciTech Connect

    Erlich, O.; Motooka, J.M.; Church, S.E.; Bailey, E.A.; Arbogast, B.F.; Willson, W.R.

    1989-01-01

    A U.S. Geological Survey report is presented detailing analytical data and sample locality map for aqua-regia leachates of stream sediments analyzed by ICP, and emission spectrographic results for both stream sediments and panned concentrates collected in 1985 from the Chandler Lake Quadrangle, Alaska.

  8. Analytical data and sample locality map for aqua-regia leachates of stream sediments analyzed by ICP, and emission spectrographic and ICP results for many NURE stream sediments from the Killik River Quadrangle, Alaska

    SciTech Connect

    Motooka, J.M.; Adrian, B.M.; Church, S.E.; McDougal, C.M.; Fife, J.B.

    1989-01-01

    A U.S. Geological Survey report is presented giving analytical data and sample locality map for aqua-regia leachates of stream sediments analyzed by ICP, and emission spectrographic and ICP results for many NURE stream sediments from the Killik River Quadrangle, Alaska.

  9. Compound-specific carbon isotopic fractionation during transport of phthalate esters in sandy aquifer.

    PubMed

    Liu, Hui; Li, YanXi; He, Xi; Sissou, Zakari; Tong, Lei; Yarnes, Chris; Huang, Xianyu

    2016-02-01

    The present paper aims to evaluate the carbon isotopic fractionation of phthalate esters (PAEs) during transport in an sandy aquifer. Breakthrough curves of di-methyl phthalate (DMP), di-ethyl phthalate (DEP), and di-n-butyl phthalate (DBP) in mixed solution were determined by miscible displacement experiment, and simulated using HYDRUS-1D software. The stable carbon isotopes (δ(13)C) of 3 PAEs in effluent were analyzed at different times. Results showed that, in the transport process in sandy sediment, PAEs are mainly trapped into the pore space instead of being adsorbed on the surface of particles. At the initial stage of transport, PAEs with lighter carbon tend to run faster in the sandy sediment, and PAEs with heavier carbon run after. However, there is no priority for the transport of PAEs with different carbon isotopes at Stage Ⅱ with mainly time-limited sorption. So the transport-based isotope fractionation occurs in the front area of contaminant plume. This effect may be relevant for interpreting carbon isotope signatures in the real contaminant site. PMID:26539707

  10. Hurricane Sandy Washover Deposits on Southern Long Beach Island, NJ

    NASA Astrophysics Data System (ADS)

    Bishop, J. M.; Richmond, B. M.; Kane, H. H.; Lunghino, B.

    2015-12-01

    Hurricane Sandy washover deposits were investigated at Forsyth National Wildlife Refuge (FNWR) on Southern Long Beach Island, New Jersey in order to map deposit thickness and characterize the sedimentary deposits. FNWR was chosen as a field area because there has been relatively little anthropogenic shoreline modification since washover deposition from Hurricane Sandy. Sediment, elevation, and geophysical data were collected during the April 2015 field campaign, approximately two and a half years after the storm. Sediment deposit data included trenches, stratigraphic descriptions, bulk sediment samples, push cores, Russian cores, and photos. Computed tomography (CT) scanning was conducted on push cores in order to acquire high resolution imaging of density, grain size, and sedimentary structure. Profiles of washover elevation were measured using Differential GPS with Real Time Kinematic processing. Ground Penetrating Radar data was collected to image the depth of the deposit and identify sedimentary structures. These data sets are compared to pre- and post -Sandy lidar surveys in order to determine post-Sandy modification in the two and a half years following the hurricane. We compare sediment thickness and sedimentary characteristics to hurricane Sandy deposits elsewhere along the U.S. eastern seaboard and to tsunami deposits.

  11. Trophic niche shifts driven by phytoplankton in sandy beach ecosystems

    NASA Astrophysics Data System (ADS)

    Bergamino, Leandro; Martínez, Ana; Han, Eunah; Lercari, Diego; Defeo, Omar

    2016-10-01

    Stable isotopes (δ13C and δ15N) together with chlorophyll a and densities of surf diatoms were used to analyze changes in trophic niches of species in two sandy beaches of Uruguay with contrasting morphodynamics (i.e. dissipative vs. reflective). Consumers and food sources were collected over four seasons, including sediment organic matter (SOM), suspended particulate organic matter (POM) and the surf zone diatom Asterionellopsis guyunusae. Circular statistics and a Bayesian isotope mixing model were used to quantify food web differences between beaches. Consumers changed their trophic niche between beaches in the same direction of the food web space towards higher reliance on surf diatoms in the dissipative beach. Mixing models indicated that A. guyunusae was the primary nutrition source for suspension feeders in the dissipative beach, explaining their change in dietary niche compared to the reflective beach where the proportional contribution of surf diatoms was low. The high C/N ratios in A. guyunusae indicated its high nutritional value and N content, and may help to explain the high assimilation by suspension feeders at the dissipative beach. Furthermore, density of A. guyunusae was higher in the dissipative than in the reflective beach, and cell density was positively correlated with chlorophyll a only in the dissipative beach. Therefore, surf diatoms are important drivers in the dynamics of sandy beach food webs, determining the trophic niche space and productivity. Our study provides valuable insights on shifting foraging behavior by beach fauna in response to changes in resource availability.

  12. Simultaneous determination of mercury and organic carbon using a direct mercury analyzer: Mercury profiles in sediment cores from oxbow lakes in the Mississippi Delta

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sediment cores from seasonal wetland and open water areas from six oxbow lakes in the Mississippi River alluvial flood plain were analyzed for total-mercury (Hg) using a direct mercury analyzer (DMA). In the process we evaluated the feasibility of simultaneously determining organic matter content by...

  13. A Multi-temporal MODIS Based Platform to Analyze Suspended Sediment Distribution Patterns in the Amazon River

    NASA Astrophysics Data System (ADS)

    Park, E.; Latrubesse, E. M.

    2014-12-01

    Patterns of surface sediment concentration distribution in rivers are significant for understanding the broad ranges of fluvial environmental systems. In the case of the Amazon Basin, complexity in sediment pattern distribution is affected by the anabranching channel pattern of the Amazon River, inputs from tributaries (some of which are among the largest rivers on earth) and the existence of huge and complex floodplains. This study presents a remote sensing based platform that aims to improve the understanding of the patterns of sediment distributions over the Amazon River by estimating surface sediment concentration. Field acquired surface sediment concentration data were supplied from three gauging stations representing the upstream, midstream and downstream sections of the Amazon River from 2000 to 2010 and calibrated with over 1,300 MODIS daily surface reflectance images. Robust empirical models were derived (0.63sediment concentration and surface reflectance data from each station; however, sensitivity of reflectance around each station was proved to be significantly affected by the local hydrological behaviors. Empirical models were applied to 8-day composite surface reflectance images to generate surface reflectance distribution maps. Overall, the capability of the MODIS-based platform introduced in this study is successfully demonstrated by capturing the spatial and temporal variability of surface sediments in the Amazon River Basin, the largest and the most complex river system on earth.

  14. Simultaneous determination of mercury and organic carbon in sediment and soils using a direct mercury analyzer based on thermal decomposition-atomic absorption spectrophotometry.

    PubMed

    Chen, Jingjing; Chakravarty, Pragya; Davidson, Gregg R; Wren, Daniel G; Locke, Martin A; Zhou, Ying; Brown, Garry; Cizdziel, James V

    2015-04-29

    The purpose of this work was to study the feasibility of using a direct mercury analyzer (DMA) to simultaneously determine mercury (Hg) and organic matter content in sediment and soils. Organic carbon was estimated by re-weighing the sample boats post analysis to obtain loss-on-ignition (LOI) data. The DMA-LOI results were statistically similar (p<0.05) to the conventional muffle furnace approach. A regression equation was developed to convert DMA-LOI data to total organic carbon (TOC), which varied between 0.2% and 13.0%. Thus, mercury analyzers based on combustion can provide accurate estimates of organic carbon content in non-calcareous sediment and soils; however, weight gain from moisture (post-analysis), measurement uncertainty, and sample representativeness should all be taken into account. Sediment cores from seasonal wetland and open water areas from six oxbow lakes in the Mississippi River alluvial flood plain were analyzed. Wetland sediments generally had higher levels of Hg than open water areas owing to a greater fraction of fine particles and higher levels of organic matter. Annual loading of Hg in open water areas was estimated at 4.3, 13.4, 19.2, 20.7, 129, and 135 ng cm(-2) yr(-1) for Beasley, Roundaway, Hampton, Washington, Wolf and Sky Lakes, respectively. Generally, the interval with the highest Hg flux was dated to the 1960s and 1970s. PMID:25847156

  15. Continuum Statistics of the Bed Topography in a Sandy River

    NASA Astrophysics Data System (ADS)

    McElroy, B.; Jerolmack, D.; Mohrig, D.

    2005-12-01

    Temporal and spatial variabilities in the bed geometry of sandy rivers contain information about processes of sediment transport that has not been fully appreciated. This is primarily due to a disparity between the dynamic nature of the sediment-fluid interface and the relatively static methods of surveying bed elevation, e.g. single profiles or point measurements. High resolution topographic data is paramount to understanding the dynamic behavior of sandy beds. We present and analyze a data set collected on a 2cm x 2cm grid at 1 minute intervals and with a vertical precision of ~1mm. This was accomplished by using Lambert-Beer's Law for attenuation of light to transform low-altitude aerial photographs into digital elevation models. Forty successive models were generated for a 20 m by 30 m section of channel bottom of the N. Loup River, Nebraska. To calculate the average, whole bed translation rate, or celerity, cross-correlations between a reference bed topography and its proceeding configurations were determined. Time differences between models were related to the shift lengths that produced correlation maxima for each model pair. The result is a celerity of ~3.8cm/s with a correlation coefficient of 0.992. Bed topography also deforms while it translates, and this can be seen as a secular decrease of correlation maxima. The form of this decrease in correlation is exponential, and from it an interface half-life is defined. In this case, the bed had become extensively reorganized within ~40 minutes, the time necessary to translate the bed one wavelength of the dominant roughness element. Although the bed is continuously deforming, its roughness is statistically stationary. Essentially, a mean roughness is maintained as the bed creates new realizations of itself. The dynamic nature of the whole bed and similarly transient behavior of individual elements suggests the utility of a holistic approach to studying the feedback between bed topography, fluid flow, and

  16. Rare earth element compositions of core sediments from the shelf of the South Sea, Korea: Their controls and origins

    NASA Astrophysics Data System (ADS)

    Jung, Hoi-Soo; Lim, Dhongil; Choi, Jin-Yong; Yoo, Hae-Soo; Rho, Kyung-Chan; Lee, Hyun-Bok

    2012-10-01

    Rare earth elements (REEs) of bulk sediments and heavy mineral samples of core sediments from the South Sea shelf, Korea, were analyzed to determine the constraints on REE concentrations and distribution patterns as well as to investigate their potential applicability for discriminating sediment provenance. Bulk sediment REEs showed large variation in concentrations and distribution patterns primarily due to grain size and carbonate dilution effects, as well as due to an abundance of heavy minerals. In the fine sandy sediments (cores EZ02-15 and 19), in particular, heavy minerals (primarily monazite and titanite/sphene) largely influenced REE compositions. Upper continental crust-normalized REE patterns of these sand-dominated sediments are characterized by enriched light REEs (LREEs), because of inclusion of heavy minerals with very high concentrations in LREEs. Notably, such a strong LREE enrichment is also observed in Korean river sediments. So, a great care must be taken when using the REE concentrations and distribution patterns of sandy and coarse silty shelf sediments as a proxy for discriminating sediment provenance. In the fine-grained muddy sediments with low heavy mineral abundance, in contrast, REE fractionation ratios and their UCC-normalized patterns seem to be reliable proxies for assessing sediment provenance. The resultant sediment origin suggested a long lateral transportation of some fine-grained Chinese river sediments (probably the Changjiang River) to the South Sea of Korea across the shelf of the northern East China Sea.

  17. Predicting toxicity to Hyalella azteca in pyrogenic-impacted sediments-Do we need to analyze for all 34 PAHs?

    PubMed

    Geiger, Stephen C; Azzolina, Nicholas A; Nakles, David V; Hawthorne, Steven B

    2016-07-01

    Polycyclic aromatic hydrocarbons (PAHs) are major drivers of risk at many urban and/or industrialized sediment sites. The US Environmental Protection Agency (USEPA) currently recommends using measurements of 18 parent + 16 groups of alkylated PAHs (PAH-34) to assess the potential for sediment-bound PAHs to impact benthic organisms at these sites. ASTM Method D7363-13 was developed to directly measure low-level sediment porewater PAH concentrations. These concentrations are then compared to ambient water criteria (final chronic values [FCVs]) to assess the potential for impact to benthic organisms. The interlaboratory validation study that was used to finalize ASTM D7363-13 was developed using 24 of the 2-, 3-, and 4-ring PAHs (PAH-24) that are included in the USEPA PAH-34 analyte list. However, it is the responsibility of the user of ASTM Method D7363 to establish a test method to quantify the remaining 10 higher molecular weight PAHs that make up PAH-34. These higher molecular weight PAHs exhibit extremely low saturation solubilities that make their detection difficult in porewater, which has proven difficult to implement in a contract laboratory setting. As a result, commercial laboratories are hesitant to conduct the method on the entire PAH-34 analyte list. This article presents a statistical comparison of the ability of the PAH-24 and PAH-34 porewater results to predict survival of the freshwater amphipod Hyalella azteca, using the original 269 sediment samples used to gain ASTM D7363 Method approval. The statistical analysis shows that the PAH-24 are statistically indistinguishable from the PAH-34 for predicting toxicity. These results indicate that the analysis of freely dissolved porewater PAH-24 is sufficient for making risk-based decisions based on benthic invertebrate toxicity (survival and growth). This reduced target analyte list should result in a cost-saving for stakeholders and broader implementation of the method at PAH-impacted sediment sites

  18. Flocculated sediments can reduce the size of sediment basin at construction sites.

    PubMed

    Kang, Jihoon; King, Scott E; McLaughlin, Richard A

    2016-01-15

    Due to stringent water quality regulations on stormwater discharges, there is increasing interest in chemically-assisted settling of suspended sediments at construction sites. This study investigated settling characteristics of flocculated sediment by polyacrylamide (PAM) in a top-loading settling tube. Studied sediment materials were obtained from construction sites in North Carolina, USA: Coastal Plain loamy sand (CPLS), Piedmont sandy clay loam (PSCL), Piedmont silt loam (PSL), and Mountain clay loam (MCL). The four different sediment suspensions mixed with and without dissolved PAM were introduced to the top of the column individually. During a 1-h settling period, samples were taken at 1-m depth from surface at various times and analyzed for total suspended solids (TSS). Flocculated sediment by PAM greatly increased its settled TSS fraction up to 95-97% only in 1-min settling period compared to those of unflocculated sediment (16-72%). The settling improvement by PAM was profound in the finer-textured soils (PSL and MCL) by increasing their median particle settling velocity (>2 cm s(-1)) compared to unflocculated counterparts (<1.1 cm s(-1)). Estimated surface area requirement of sediment basin suggested that the basins receiving flocculated sediment could be reduced in size (surface area) by 2- to 4-times compared to those receiving unflocculated sediment. Our results suggests that current sediment basin design could be modified when chemically-assisted settling is implemented, taking up less space and cost in construction sites. PMID:26555101

  19. In situ estimation of sediment sound speed and critical angle

    PubMed

    Maguer; Bovio; Fox; Schmidt

    2000-09-01

    Understanding the basic physics of sound penetration into ocean sediments is essential for the design of sonar systems that can detect, localize, classify, and identify buried objects. In this regard the sound speed of the sediment is a crucial parameter as the ratio of sound speed at the water-sediment interface determines the critical angle. Sediment sound speed is typically measured from core samples using high frequency (100's of kHz) pulsed travel time measurements. Earlier experimental work on subcritical penetration into sandy sediments has suggested that the effective sound speed in the 2-20 kHz range is significantly lower than the core measurement results. Simulations using Biot theory for propagation in porous media confirmed that sandy sediments may be highly dispersive in the range 1-100 kHz for the type of sand in which the experiments were performed. Here it is shown that a direct and robust estimate of the critical angle, and therefore the sediment sound speed, at the lower frequencies can be achieved by analyzing the grazing angle dependence of the phase delays observed on a buried array. A parametric source with secondary frequencies in the 2-16 kHz range was directed toward a sandy bottom similar to the one investigated in the earlier study. An array of 14 hydrophones was used to measure penetrated field. The critical angle was estimated by analyzing the variations of signal arrival times versus frequency, burial depth, and grazing angle. Matching the results with classical transmission theory yielded a sound speed estimate in the sand of 1626 m/s in the frequency range 2-5 kHz, again significantly lower the 1720 m/s estimated from the cores at 200 kHz. However, as described here, this dispersion is consistent with the predictions of the Biot theory for this type of sand. PMID:11008802

  20. Effects of Super Strom Sandy on Depositional Environments Offshore Long Island, New York

    NASA Astrophysics Data System (ADS)

    Hosseini, P.; McHugh, C. M.; Christensen, B. A.; Dutton, J.; Brownawell, B.; Gurung, D.

    2013-12-01

    Hurricane Sandy's landfall affected the coastlines over a broad swath of mid-Atlantic including New York, New Jersey, Delaware, Maryland, Virginia, and North Carolina. The effects included breaching, overwash and erosion of barrier islands, some of which are heavily populated and sustained extensive damage. The peak storm-tide elevation produced by Hurricane Sandy measured by USGS stations in Jamaica Bay was about 3.5 m, 1.4 m more than the historical peak-water level elevations in the same area. As part of a National Science Foundation RAPID response we sampled the sediment in West Bay, Middle Bay, East Bay, Jones Inlet and Reynolds Channel of Long Island, New York from the R/V Pritchard. The sediment sampling took place 4 months after the storm and prior to any similar large storms. The sampling strategy was designed to characterize the post-storm sedimentation in distinct depositional environments. In this survey 156 grab samples were recovered from areas, many of which had been sampled prior to the storm. The samples were analyzed for grain size variability, short-lived radioisotopes and x-ray fluorescence elemental analyses. Google Earth images from before and after the storm reveal moderate to severe erosion and overwash of the dunes in Jones inlet, and Middle and East Bays. The Long Beach barrier island tidal marshes were submerged for several days post Sandy and underwent severe erosion. The storm surge brought from offshore a layer of coarse sand that was deposited over mussel beds. Most of the mussels were dead indicative of the strength of the waves. Be-7 concentrations allowed tracking the path of the storm from the bays and inlets, to the offshore. Some of the highest Be-7 concentrations ever detected in the local estuaries: 5,329, 4,955 and 4,553 pCi/kg were measured in West Bay and Middle Bay Channels. Additionally, unusually high Be-7 concentrations of 2,130 pCi/kg were recorded ~5.24 km offshore from Long Beach barrier island four months after the

  1. Tsunami characteristics and formation potential of sandy tsunami deposit in Sanriku Coast: implications from numerical modeling

    NASA Astrophysics Data System (ADS)

    Sugawara, D.; Haraguchi, T.; Takahashi, T.

    2013-12-01

    Geological investigation of paleotsunami deposit is crucial for knowing the history and magnitude of tsunami events in the past. Among various kinds of grain sizes, sandy tsunami deposit has been best investigated by previous studies, because of its potential for identification in the sedimentary column. Many sandy tsunami deposits have been found from coastal plains, which have sandy beach and low-lying wetlands. However, sandy tsunami deposits in narrow valleys at rocky ria coast have rarely been found. It may be presumed that formation potential of sandy tsunami layer in the rocky coasts is generally lower than coastal plains, because of the absence of sandy beach, tsunami run-up on steeper slope and stronger return flow. In this presentation, characteristics of the 2011 Tohoku-oki earthquake tsunami in Sanriku Coast, a continuous rocky ria coast located in the northeast Japan, is investigated based on numerical modeling. In addition, the formation potential of sandy tsunami deposit is also investigated based on numerical modeling of sediment transport. Preliminary result of tsunami hydrodynamics showed that the waveform and amplification of the tsunami are clearly affected by the local bathymetry, which is associated with submerged topography formed during the last glacial stage. Although the tsunami height in the offshore of each bay is around 8.0 m, the tsunami height at the bay head was increased in different way. The amplification factor at the bay head was typically 2.0 among most of V-shaped narrow embayments; meanwhile the amplification factor is much lower than 1.0 at some cases. The preliminary result of the modeling of sediment transport predicted huge amount of sediments may be suspended into the water column, given that sandy deposit is available there. Massive erosion and deposition of sea bottom sediments may commonly take place in the bays. However, formation of onshore tsunami deposit differs from each other. Whether the suspended sediments

  2. INNOVATIVE TECHNOLOGY VERIFICATION REPORT XRF TECHNOLOGIES FOR MEASURING TRACE ELEMENTS IN SOIL AND SEDIMENT XCALIBUR ELVAX XRF ANALYZER

    EPA Science Inventory

    The Innov-X XT400 Series (XT400) x-ray fluorescence (XRF) analyzer was demonstrated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program. The field portion of the demonstration was conducted in January 2005 at the Kenned...

  3. INNOVATIVE TECHNOLOGY VERIFICATION REPORT XRF TECHNOLOGIES FOR MEASURING TRACE ELEMENTS IN SOIL AND SEDIMENT RONTEC PICOTAX XRF ANALYZER

    EPA Science Inventory

    The Rontec PicoTAX x-ray fluorescence (XRF) analyzer was demonstrated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program. The field portion of the demonstration was conducted in January 2005 at the Kennedy Athletic, Rec...

  4. FIELD MEASUREMENT TECHNOLOGY FOR MERCURY IN SOIL AND SEDIMENT OHIO LUMEX'S RA-915+/RP-91C MERCURY ANALYZER

    EPA Science Inventory

    Ohio Lumex's RA915+/91 C mercury analyzer was demonstrated under the U.S. Environmental Protection Agency Superfund Innovative Technology Evaluation Program in May 2003, at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The purpose of the Demonstration was to c...

  5. INNOVATIVE TECHNOLOGY VERIFICATION REPORT XRF TECHNOLOGIES FOR MEASURING TRACE ELEMENTS IN SOIL AND SEDIMENT OXFORD ED2000 XRF ANALYZER

    EPA Science Inventory

    The Oxford ED2000 x-ray fluorescence (XRF) analyzer was demonstrated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program. The field portion of the demonstration was conducted in January 2005 at the Kennedy Athletic, Recr...

  6. INNOVATIVE TECHNOLOGY VERIFICATION REPORT XRF TECHNOLOGIES FOR MEASURING TRACE ELEMENTS IN SOIL AND SEDIMENT RIGAKU ZSX MINI 11 XRF ANALYZER

    EPA Science Inventory

    The Rigaku ZSX Mini II (ZSX Mini II) XRF Services x-ray fluorescence (XRF) analyzer was demon-strated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program. The field portion of the demonstration was conducted in January 2...

  7. FIELD MEASUREMENT TECHNOLOGY FOR MERCURY IN SOIL AND SEDIMENT NITON'S XLI/XLT 700 SERIES X-RAY FLUORESCENCE ANALYZER

    EPA Science Inventory

    NITON's XL-700 Series X-ray fluorescence analyzers were demonstrated under the U.S. Environmental Protection Agency Superfund Innovative Technology Evaluation Program in May 2003 at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The purpose of the Demonstration...

  8. INNOVATIVE TECHNOLOGY VERIFICATION REPORT XRF TECHNOLOGIES FOR MEASURING TRACE ELEMENTS IN SOIL AND SEDIMENT NITON XLT700 SERIES XRF ANALYZER

    EPA Science Inventory

    The Niton XLt 700 Series (XLt) XRF Services x-ray fluorescence (XRF) analyzer was demonstrated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program. The field portion of the demonstration was conducted in January 2005 at ...

  9. FIELD MEASUREMENT TECHNOLOGY FOR MERCURY IN SOIL AND SEDIMENT MILESTONE INC.'S DIRECT MERCURY ANALYZER (DMA)-80

    EPA Science Inventory

    Milestone's Direct Mercury Analyzer (DMA-80) was demonstrated under the U.S. Environmental Protection Agency Superfund Innovative Technology Evaluation Program in May 2003 at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The purpose of the Demonstration was to...

  10. Reciprocal influences of microbial community and hydrogeomorphology in sandy streambeds

    NASA Astrophysics Data System (ADS)

    Mendoza-Lera, C.; Federlein, L. L.; Frossard, A.; Gessner, M. O.; Knie, M.; Mutz, M.

    2015-12-01

    Stream hydrogeomorphology is a strong determinant of streambed microbial community activity, which in turn influences stream biogeochemistry. Whether this influence is unidirectional or whether microbial communities can also modulate biogeochemical processes by affecting hydrogeomorphology is an emerging question in research on sediment-water interfaces. Using experimental flumes simulating sandy streams, we tested whether such influences can occur through altered water exchange across the sediment-water interface. Results show that microbial communities in sandy streambeds can indeed affect hydrogeomorphology by producing gas bubbles. Specifically, gas bubbles accumulating in microbial biofilms can alter the water exchange by (i) reducing sediment pore space or (ii) provoking the detachment of the microbial biofilm detachment and thus altering streambed topography. Additionally, results indicate that water exchange is the major for the structure and activity of the microbial community. Our data also indicate that the potential of microbial communities to influence water exchange can be modulated by factors such as light intensity and discharge fluctuations. These biological-physical interactions and their effects on the influence of microbial communities on hydrogeomorphology is a source of spatiotemporal variability in water exchange across the sediment-water interface. Heterogeneity in water exchange is known to increase biogeochemical pathways and, thus, ecosystem functions. These results suggest that a holistic understanding of vertical connectivity in running waters requires consideration of biological-physical interactions at the water-sediment interface.

  11. Hurricane Sandy -- Pass 1, Oct. 29, 2012

    NASA Video Gallery

    Hurricane Sandy was viewed Monday morning from the International Space Station as it orbited 260 miles above the Atlantic Ocean. Sandy had sustained winds of 90 miles an hour as the station passed ...

  12. Hurricane Sandy Prowls the Eastern Seaboard

    NASA Video Gallery

    An animation of satellite observations from Oct. 26-29, 2012, shows Hurricane Sandy move along the U.S. East coast and into the Mid-Atlantic and northeastern U.S. Sandy had still not made landfall ...

  13. On Sandy Shores. Teacher's Guide.

    ERIC Educational Resources Information Center

    Strang, Craig; And Others

    The activities in this guide (for grades 2-4) transport students to the sandy shore, one of the most fascinating ecosystems on the planet. At this ecological juncture a multiplicity of life forms find ways to survive, thrive, and interact with each other. Using a wide variety of learning formats, students explore and deepen their understanding of…

  14. Evaluation of the SediMax automated microscopy sediment analyzer and the Sysmex UF-1000i flow cytometer as screening tools to rule out negative urinary tract infections.

    PubMed

    Íñigo, Melania; Coello, Andreu; Fernández-Rivas, Gema; Carrasco, María; Marcó, Clara; Fernández, Anabel; Casamajor, Teresa; Ausina, Vicente

    2016-05-01

    Urinary tract infections (UTI) are highly prevalent in nosocomial and community settings, and their diagnosis is costly and time-consuming. Screening methods represent an important advance towards the final UTI diagnosis, diminishing inappropriate treatment or clinical complications. Automated analyzers have been developed and commercialized to screen and rule out negative urine samples. The aim of this study was to evaluate two of these automated analyzers (SediMax, an automatic sediment analyzer and UF-1000i a flow cytometer) to predict negative urine cultures. A total of 1934 urine samples were analyzed. A very strong correlation for white blood cells (WBC) (rs: 0.928) and a strong correlation for bacteria (BAC) (rs: 0.693) were obtained. We also calculated optimal cut-off points for both autoanalyzers: 18WBC/μL and 97BAC/μL for SediMax (sensitivity=96.25%, specificity=63.04%, negative predictive value=97.97%), and 40WBC/μL and 460BAC/μL for UF-1000i (sensitivity=98.13%, specificity=79.16%, negative predictive value=99.18%). The use of SediMax and UF-1000i resulted in a 46.33% and 57.19% reduction of all samples cultured, respectively. In conclusion, both analyzers are good UTI screening tools in our setting. PMID:26921459

  15. Experimental Study of Clay Deposition and Storage in Sandy River Beds

    NASA Astrophysics Data System (ADS)

    Wysocki, N.; Hajek, E. A.

    2014-12-01

    Ancient fluvial deposits are important records of historical surface conditions on Earth and also serve as important reservoir units for groundwater and hydrocarbons. Grain-size heterogeneity within fluvial deposits may record paleo-flow variability and/or paleo-sediment supply, but without improved understanding of the conditions under which clay can accumulate in sandy river beds, it is difficult to uniquely interpret these deposits. In order to better understand the processes controlling when and where fine sediment accumulates in sandy river beds, we conducted a series of physical experiments to test if there is a relationship between supplied clay concentration and the amount of clay preserved in the river bed under constant and variable discharge conditions. In a 15.5 m feed-style flume, water discharge of 0.21 m3/s and sand supply of 15 g/s were used to aggrade a sandy bed 6.5 cm over the course of 4 hours. In three constant-discharge experiments, clay was added in concentrations of 1000 mg/l, 4000 mg/l and 8500 mg/l. An additional experiment with 1000 mg/l clay concentration was conducted with variable water-discharge, where discharge was slowed to a stop every hour of run time and clay allowed to settle for one hour and once overnight. After each experiment, clay deposits observable in the bed were mapped and samples were collected from the dry bed and analyzed for clay content. Results demonstrate that under constant discharge conditions, clay can accumulate in the bed and that the amount of clay retained in the bed is related to the amount of clay supplied to the flume. In sediment deposited with a low clay concentration, little to no clay accumulated in the bed while under high clay concentration, as much five percent of the bed had a high clay fraction. Clay accumulations that formed under constant flow conditions had different distribution and character from those formed under variable discharge conditions. In all experiments, clay retention was

  16. Science and Sandy: Lessons Learned

    NASA Astrophysics Data System (ADS)

    Werner, K.

    2013-12-01

    Following Hurricane Sandy's impact on the mid-Atlantic region, President Obama established a Task Force to '...ensure that the Federal Government continues to provide appropriate resources to support affected State, local, and tribal communities to improve the region's resilience, health, and prosperity by building for the future.' The author was detailed from NOAA to the Task Force between January and June 2013. As the Task Force and others began to take stock of the region's needs and develop plans to address them, many diverse approaches emerged from different areas of expertise including: infrastructure, management and construction, housing, public health, and others. Decision making in this environment was complex with many interests and variables to consider and balance. Although often relevant, science and technical expertise was not always at the forefront of this process. This talk describes the author's experience with the Sandy Task Force focusing on organizing scientific expertise to support the work of the Task Force. This includes a description of federal activity supporting Sandy recovery efforts, the role of the Task Force, and lessons learned from developing a science support function within the Task Force.

  17. 6. SANDY RIVER BRIDGE AT TROUTDALE, EAST ELEVATION, LOOKING 306 ...

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

    6. SANDY RIVER BRIDGE AT TROUTDALE, EAST ELEVATION, LOOKING 306 DEGREES NORTHWEST. - Historic Columbia River Highway, Sandy River Bridge at Troutdale, Historic Columbia River Highway spanning Sandy River, Troutdale, Multnomah County, OR

  18. 3. SANDY RIVER BRIDGE AT TROUTDALE, NORTH END, LOOKING 184 ...

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

    3. SANDY RIVER BRIDGE AT TROUTDALE, NORTH END, LOOKING 184 DEGREES SOUTH. SAME PHOTO AS OR-36-2. - Historic Columbia River Highway, Sandy River Bridge at Troutdale, Historic Columbia River Highway spanning Sandy River, Troutdale, Multnomah County, OR

  19. 7. SANDY RIVER BRIDGE AT TROUTDALE, PERSPECTIVE LOOKING EAST. ...

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

    7. SANDY RIVER BRIDGE AT TROUTDALE, PERSPECTIVE LOOKING EAST. - Historic Columbia River Highway, Sandy River Bridge at Troutdale, Historic Columbia River Highway spanning Sandy River, Troutdale, Multnomah County, OR

  20. 1. SANDY RIVER BRIDGE AT TROUTDALE, SOUTH END, LOOKING 18 ...

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

    1. SANDY RIVER BRIDGE AT TROUTDALE, SOUTH END, LOOKING 18 DEGREES NORTH. SAME PHOTO AS OR-36-1. - Historic Columbia River Highway, Sandy River Bridge at Troutdale, Historic Columbia River Highway spanning Sandy River, Troutdale, Multnomah County, OR

  1. 2. SANDY RIVER BRIDGE AT TROUTDALE, SOUTH END, LOOKING 20 ...

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

    2. SANDY RIVER BRIDGE AT TROUTDALE, SOUTH END, LOOKING 20 DEGREES NORTH. - Historic Columbia River Highway, Sandy River Bridge at Troutdale, Historic Columbia River Highway spanning Sandy River, Troutdale, Multnomah County, OR

  2. 5. SANDY RIVER BRIDGE AT TROUTDALE, EAST ELEVATION DETAIL, LOOKING ...

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

    5. SANDY RIVER BRIDGE AT TROUTDALE, EAST ELEVATION DETAIL, LOOKING 6 DEGREES NORTH. - Historic Columbia River Highway, Sandy River Bridge at Troutdale, Historic Columbia River Highway spanning Sandy River, Troutdale, Multnomah County, OR

  3. 4. SANDY RIVER BRIDGE AT TROUTDALE, NORTH END, LOOKING 224 ...

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

    4. SANDY RIVER BRIDGE AT TROUTDALE, NORTH END, LOOKING 224 DEGREES SOUTHWEST. - Historic Columbia River Highway, Sandy River Bridge at Troutdale, Historic Columbia River Highway spanning Sandy River, Troutdale, Multnomah County, OR

  4. The surface sediment types and their rare earth element characteristics from the continental shelf of the northern south China sea

    NASA Astrophysics Data System (ADS)

    Wang, Shuhong; Zhang, Nan; Chen, Han; Li, Liang; Yan, Wen

    2014-10-01

    The grain size as well as some major and trace elements, including rare earth element (REE), for 273 surface sediment samples collected from the continental shelf of the northern South China Sea were analyzed in this study. The sediment types are mainly sandy silt and silt, making up 60% of the whole samples, and secondly are mud, sandy mud, muddy sand and silty sand, making up 28% of the whole samples, based on grain-size in which the Folk's classification was used. The total REE content (ΣREE) show a wide variation from 21 ppm to 244 ppm with an average value of 155 ppm, which similar to the average ΣREE of the China loess, but much different from that in deep-sea clay, showing a significant terrigenous succession. The REE contents in different sediment types vary greatly, mainly enriching in silt, sandy silt, mud and sandy mud. The REE distribution contours parallel to the coastal, presenting like strips and their contents gradually reduce with increasing distance from the coast. The high content of the western Pearl River Mouth, Shang/Xiachuan Islands and Hailing Bay might be regarded to the coastal current developed from the east to the west along to the Pearl River Mouth in the northern South China Sea. But the chondrite-normalized REE patterns in various sediment types have no difference, basically same as those of coastal rivers and upper crust. They all show relative enrichments in light rare earth element (LREE), noticeable negative Eu anomaly and no Ce anomaly, indicating that those sediments are terrigenous sediments and from the same source region. Further analysis suggest that the sedimentary environment in the study area is relatively stable and granite widely distributed in the South China mainland is the main source of REE, which are transported mainly by the Pearl River. The late diagenesis has little effect on the REE.

  5. Geoacoustic inversion in shallow tropical waters for a silty and sandy seabed.

    PubMed

    M C, Sanjana; G, Latha; Potty, G R

    2016-02-01

    Seabed parameters are inverted from ambient noise measurements at two shallow tropical environments with dissimilar seabed characteristics, a silty and a sandy seabed, using an approach that matches the measured and modeled complex vertical coherence. Coherence is modeled using the Green's function output from the model oases, along with theoretical formulation, for a range independent environment. Genetic algorithm is used to search the model parameter space consisting of sound speed, density, and attenuation in the sediment layers and half-space. Reasonable estimates have been obtained for the silty site, whereas the sandy site gave relatively poor parameter estimates due to reflective seabed and shipping interference. PMID:26936582

  6. Quantifying the digital traces of Hurricane Sandy on Flickr.

    PubMed

    Preis, Tobias; Moat, Helen Susannah; Bishop, Steven R; Treleaven, Philip; Stanley, H Eugene

    2013-01-01

    Society's increasing interactions with technology are creating extensive "digital traces" of our collective human behavior. These new data sources are fuelling the rapid development of the new field of computational social science. To investigate user attention to the Hurricane Sandy disaster in 2012, we analyze data from Flickr, a popular website for sharing personal photographs. In this case study, we find that the number of photos taken and subsequently uploaded to Flickr with titles, descriptions or tags related to Hurricane Sandy bears a striking correlation to the atmospheric pressure in the US state New Jersey during this period. Appropriate leverage of such information could be useful to policy makers and others charged with emergency crisis management. PMID:24189490

  7. Quantifying the Digital Traces of Hurricane Sandy on Flickr

    NASA Astrophysics Data System (ADS)

    Preis, Tobias; Moat, Helen Susannah; Bishop, Steven R.; Treleaven, Philip; Stanley, H. Eugene

    2013-11-01

    Society's increasing interactions with technology are creating extensive ``digital traces'' of our collective human behavior. These new data sources are fuelling the rapid development of the new field of computational social science. To investigate user attention to the Hurricane Sandy disaster in 2012, we analyze data from Flickr, a popular website for sharing personal photographs. In this case study, we find that the number of photos taken and subsequently uploaded to Flickr with titles, descriptions or tags related to Hurricane Sandy bears a striking correlation to the atmospheric pressure in the US state New Jersey during this period. Appropriate leverage of such information could be useful to policy makers and others charged with emergency crisis management.

  8. A preliminary comparative assessment of the meiofaunal communities of Maltese pocket sandy beaches

    NASA Astrophysics Data System (ADS)

    Kotwicki, Lech; Deidun, Alan; Grzelak, Katarzyna; Gianni, Fabrizio

    2014-10-01

    Whilst the macrofaunal communities of Maltese pocket sandy beaches have been extensively studied, the meiofaunal communities of the same beaches are virtually unknown. The main aims of the current study include the acquisition of preliminary data on the occurrence of meiofaunal higher taxa on Maltese pocket sandy beaches, the comparison between the Maltese beach meiofaunal communities with those on other Mediterranean sandy beaches and the assessment of the influence of a selected number of beach physical parameters on the same communities. Seven sandy beaches in the Maltese Islands were sampled during spring 2012, with sediment samples being collected at the Mean Sea Level (mediolittoral zone). Median grain size and sediment organic and water content were measured for each beach. A total of 13 higher meiofaunal taxa were recorded from the Maltese sandy beaches. The meiofaunal abundance ranged between 50 and 1392 individuals/10 cm2, whilst the number of meiofaunal higher taxa recorded at a single sampling station ranged between 5 and 10. Mean grain size and sorting coefficient appeared to have the highest influence on variations in Maltese meiofaunal communities. Based on conducted analysis it is suggested that inter-beach dispersal of meiofaunal propagules for Maltese beaches is restricted to short distances and does not operate over distances exceeding 5-10 km. This in turn results in some degree of compartmentalisation of the same assemblages. The meiofaunal assemblages recorded from the Maltese beaches exhibited comparable densities to those recorded on other Central Mediterranean sandy beaches and no significant differences in community structure at higher taxa level were observed.

  9. Technical Note: Medium-term morphodynamics in an unprotected sandy beach of the Adriatic Sea

    NASA Astrophysics Data System (ADS)

    Postacchini, M.; Soldini, L.; Lorenzoni, C.; Mancinelli, A.

    2015-08-01

    In the recent years attention has been paid to the beach protection by means of soft and hard defenses. Along the Italian coasts of the Adriatic Sea, sandy beaches are the most common landscapes and around 70 % of the Marche-Region coasts (central Adriatic), is protected by defense structures. The longest free-from-obstacle nearshore area in the Region includes the beach of Senigallia, characterized by a multiple barred beach, frequently monitored during the last decades. The bathymetries surveyed in 2006, 2010, 2011, 2012 and 2013 show a good adaptation of the beach to the Dean-type equilibrium profile, though a strong short-/medium-term variability of the wave climate has been observed during the monitored periods. This suggests a slight influence of wave forcing on the long-term profiles, which seems to only depend on the sediment size. Further, the medium-term dynamics of the submerged bars and their geometric features have been related to the wave climate collected by a wave buoy located 40 km off Senigallia during the analyzed temporal windows. An overall interpretation of the complete dynamics, i.e. hydrodynamics (buoy data), sediment characteristics (equilibrium-profile A parameter) and morphodynamics (bathymetric surveys), suggests that the wave climate is fundamental for the morphodynamic changes of the beach in the medium term: waves coming from NNE/ESE are characterized by a larger/smaller steepness and induce seaward/shoreward bar migration, as well as bar smoothing/steepening. Moving southward, the bar dimension increases, while the equilibrium profile suggests a decrease of the sediment size in the submerged beach, this probably due to the presence of both harbor jetty and river mouth North of the investigated area.

  10. Analyzing turbidity, suspended-sediment concentration, and particle-size distribution resulting from a debris flow on Mount Jefferson, Oregon, November 2006

    USGS Publications Warehouse

    Uhrich, Mark A.

    2010-01-01

    A debris flow and sediment torrent occurred on the flanks of Mt Jefferson in Oregon on November 6, 2006, inundating 150 acres of forest. The massive debris flow was triggered by a rock and snow avalanche from the Milk Creek glaciers and snowfields during the early onset of an intense storm originating near the Hawaiian Islands. The debris flow consisted of a heavy conglomerate of large boulders, cobbles, and coarse-grained sediment that was deposited at depths of up to 15 ft and within 3 mi of the glaciers, and a viscous slurry that deposited finer-grained sediments at depths of 0.5 to 3 ft. The muddy slurry coated standing trees within the lower reaches of Milk Creek as it moved downslope.

  11. Hurricane Sandy From the International Space Station

    NASA Video Gallery

    The International Space Station flew high above Hurricane Sandy just before 12 p.m. CDT Thursday. The storm was located about 85 miles south-southeast of Great Exuma Island. The storm’s maximum s...

  12. Constraining Depositional Slope From Sedimentary Structures in Sandy Braided Streams

    NASA Astrophysics Data System (ADS)

    Lynds, R. M.; Mohrig, D.; Heller, P. L.

    2003-12-01

    Determination of paleoslopes in ancient fluvial systems has potentially broad application to quantitatively constraining the history of tectonics and paleoclimate in continental sequences. Our method for calculating paleoslopes for sandy braided streams is based upon a simple physical model that establishes depositional skin-frictional shear stresses from assemblages of sedimentary structures and their associated grain size distributions. The addition of a skin-frictional shear stress, with a geometrically determined form-drag shear stress results in a total boundary shear stress which is directly related to water-surface slope averaged over an appropriate spatial scale. In order to apply this model to ancient fluvial systems, it is necessary to measure the following: coarsest suspended sediment size, finest grain size carried in bed load, flow depth, dune height, and dune length. In the rock record, suspended load and bed load can be accurately assessed by well-preserved suspended load deposits ("low-energy" ripples) and bed load deposits (dune foresets). This model predicts an average slope for the North Loup River near Taylor, Nebraska (modern case study) of 2.7 x 10-3. The measured reach-averaged water surface slope for the same reach of the river is 1.37 x 10-3. We suggest that it is possible to calculate the depositional slope of a sandy fluvial system by a factor of approximately two. Additionally, preliminary application of this model to the Lower Jurassic Kayenta Formation throughout the Colorado Plateau provides a promising and consistent evaluation of paleoslope in an ancient and well-preserved, sandy braided stream deposit.

  13. Superstorm Sandy and the Verdant Power RITE Project

    NASA Astrophysics Data System (ADS)

    Corren, D.; Colby, J.; Adonizio, M.

    2013-12-01

    River water speed and level data acquired during Sandy is revelatory, not only indicating the extent and timing of the extraordinarily high levels, but also significant changes to the very sense of the tidal flows. This unique observational data provides an invaluable insight for Verdant Power, the marine and hydrokinetic (MHK) industry, and researchers studying the potential effects of extreme storms on New York City and potential countermeasures. In this paper, Verdant first presents the East River data collected during Superstorm Sandy, indicating what actually happened during the storm. Verdant provides further analyses and estimates of the potential for yet more extreme water levels due to different storm timing relative to the astronomical tides. These results should also provide additional insights for measures to prepare for extreme storms in the New York City area. Specific to Verdant Power, as a renewable energy developer, we also analyze the data to estimate how a different storm timing could affect the water velocity through the river. We relate these findings to the design criteria for our turbines and associated equipment, and draw conclusions about the potential impact of an extreme storm such as Sandy on a commercial array of kinetic hydropower turbines.

  14. Simulation and control of morphological changes due to dam removal in the Sandy River, Oregon, USA

    NASA Astrophysics Data System (ADS)

    Ding, Y.; Altinakar, M. S.

    2015-03-01

    A one-dimensional channel evolution simulation model (CCHE1D) is applied to assess morphological changes in a reach of the Sandy River, Oregon, USA, due to the Marmot Dam removal in 2007. Sediment transport model parameters (e.g. sediment transport capacity, bed roughness coefficient) were calibrated using observed bed changes after the dam removal. The validated model is then applied to assess long-term morphological changes in response to a 10-year hydrograph selected from historical storm water records. The long-term assessment of sedimentation gives a reasonable prediction of morphological changes, expanding erosion in reservoir and growing deposition immediately downstream of the dam site. This prediction result can be used for managing and planning river sedimentation after dam removal. A simulation-based optimization model is also applied to determine the optimal sediment release rates during dam-removal that will minimize the morphological changes in the downstream reaches.

  15. The Topic Is Sandy Hook: A Program for Gifted and Talented Students at Sandy Hook.

    ERIC Educational Resources Information Center

    Grant, David

    "The Topic Is Sandy Hook" is an experiential 10-week program designed to provide special opportunities and educational experiences for 6th to 10th grade gifted and talented students. Sandy Hook, a natural resource in Monmouth County, New Jersey, is unique in its physical and historical features and provides an exceptionally rich environment in…

  16. [Diversity of diazotrophs in the sediments of hypersaline salt and soda lakes analyzed with the use of the nifH gene as a molecular marker].

    PubMed

    Turova, T P; Slobodova, N V; Bumazhkin, B K; Sukhacheva, M V; Sorokin, D Iu

    2014-01-01

    Phylogenetic analysis of the nifH genes, encoding the Fe protein of the nitrogenas enzymatic complex, was carried out for pure cultures of anoxygenic phototrophic bacteria of diverse origin, as well as for heterotrophic alkaliphilic sulfate reducers isolated from saline and soda lakes. Topology of the nitrogenase tree correlated with that of the 16S rRNAgene tree to a considerable degree; which niade it possible to use the nifH gene as a molecular marker for investigation of diazotrophic bacterialcommunities in silty sediments of saline and sodalakes. Although diazotrophs were revealed in all environmentalsamples, their phylogenetic diversity was relatively low. Sulfate-reducing deltaproteobacteria and photo- and chemotrophicgammaproteobacteria were predominant in samples integrated over sediment thickness. Analysis of samples fromthe upper sediment layers revealed predominance of phototrophic diazotrophs of various phyla, including purple sulfur and nonsulfur proteobacteria, green nonsulfur bacteria, heliobacteria; and cyanobacteria. Some phylotypes could not be identified, probably indicating the presence of bacterial groups which have not yet been studied by conventional microbiological techniques. PMID:25844470

  17. Variations in macrobenthic community structure in relation to changing environmental conditions in sandy beaches of Argentina

    NASA Astrophysics Data System (ADS)

    Carcedo, M. Cecilia; Fiori, Sandra M.; Piccolo, M. Cintia; López Abbate, M. Celeste; Bremec, Claudia S.

    2015-12-01

    This study describes for the first time the intertidal macrobenthic community of exposed sandy beaches located near the Bahía Blanca Estuary (38°S) and reports the physical characterization of this coastal fringe. The main objective of the study was to link environmental variables to biotic information, analyzing the results in the context of the Swash Exclusion Hypothesis (SEH) and possible estuarine influence. Four beaches were sampled seasonally at different distances from the mouth of the Bahía Blanca Estuary. To characterize the morphodynamic state of the beaches, the Dean parameter (Ω) was calculated. Multivariate analyses were used to assess benthic community structures and their relationships with physical variables. The two beaches located closest to the Bahía Blanca Estuary were classified as intermediate and those located further from the estuary as dissipative. Richness, diversity and biomass of intertidal macrobenthic communities varied with the SEH, increasing towards the dissipative beaches. However, total density was higher on intermediate beaches, possibly because of nutrient-rich silt-clay sediment input from the estuary, enabling them to maintain a higher density of organisms than dissipative beaches. The estuary acts as a moderator of habitat hardness, which together with the morphodynamic state of the beaches is an important factor in the structuring of the macrobenthic community along this coastal fringe.

  18. Hurricane Sandy washover deposits on southern Long Beach Island, New Jersey

    USGS Publications Warehouse

    Bishop, James M.; Richmond, Bruce M.; Zaremba, Nicholas J.; Lunghino, Brent D.; Kane, Haunani H.

    2016-01-01

    Sedimentologic and topographic data from Hurricane Sandy washover deposits were collected from southern Long Beach Island, New Jersey, in order to document changes to the barrier-island beaches, dunes, and coastal wetlands caused by Hurricane Sandy and subsequent storm events. These data will provide a baseline dataset for use in future coastal change descriptive and predictive studies and assessments. The data presented here were collected as part of the U.S. Geological Survey’s Barrier Island and Estuarine Wetland Physical Change Assessment Project (http://coastal.er.usgs.gov/sandy-wetland-assessment/), which aims to assess ecological and societal vulnerability that results from long- and short-term physical changes to barrier islands and coastal wetlands. This report describes data that were collected in April 2015, approximately 2½ years after Hurricane Sandy’s landfall on October 29, 2012. During the field campaign, washover deposits were photographed and described, and sediment cores, sediment samples, and surface-elevation data were collected. Data collected during this study, including sample locations and elevations, core photographs, computed tomography scans, descriptive core logs, sediment grain-size data, and accompanying Federal Geographic Data Committee metadata, are available in the associated U.S. Geological Survey data release (Bishop and others, 2016; http://dx.doi.org/10.5066/F7PK0D7S).

  19. Emergency evacuation orders: considerations and lessons from Hurricane Sandy.

    PubMed

    O'Neil, Patrick D

    2014-01-01

    This article analyzes the problems surrounding the execution of emergency evacuation orders by evaluating Hurricane Sandy and the emergency actions taken by the State of New Jersey and the City of Atlantic City New Jersey. The analysis provides an overview of the legal authority granting emergency powers to governors and mayors to issue evacuation proclamations in addition to an evaluation of the New Jersey's emergency evacuation mandate and subsequent compliance. The article concludes with provision of planning and preparedness recommendations for public managers facing similar hazards, including a recommendation for provision of emergency shelter contingencies within the threat zone in anticipation of citizen noncompliance evacuation orders. PMID:25062822

  20. Satellite Observations Monitor Outages From Superstorm Sandy

    NASA Astrophysics Data System (ADS)

    Molthan, Andrew; Jedlovec, Gary

    2013-01-01

    In late October 2012, Hurricane Sandy traveled across Jamaica, Cuba, and the Bahamas, then progressed northward along the eastern seaboard of the United States, resulting in numerous tropical storm warnings along the coasts of Florida and North Carolina. As the storm approached the Mid-Atlantic region, interaction with an upper-level low drew the cyclone inland, with the center passing just north of Atlantic City, N. J. In what media reports dubbed a "superstorm," Sandy produced hurricane-force winds, significant coastal storm surge, torrential rain, inland flooding, and extensive damage over a vast area. Further west of the cyclone center, strong winds increased wave activity throughout the Great Lakes, and heavy snowfall occurred across portions of Tennessee, Kentucky, and West Virginia. As of early November, more than 100 fatalities had been attributed to Sandy in the northeastern United States, with total economic losses of up to $50 billion [New York Times, 2012, and Walsh and Schwartz, 2012].

  1. Physical and geoacoustic properties of surface sediments in the southwestern Ulleung Basin, East Sea of Korea

    NASA Astrophysics Data System (ADS)

    Kim, S.; Kim, D. C.; Lee, G.; Kim, S. P.; Bae, S.

    2012-12-01

    To investigate the physical and geoacoustic properties of surface sediments in the southwestern Ulleung Basin, East Sea of Korea, eighty-two piston cores and sixty-six box cores were analyzed for sediment texture (grain size, sand, silt and clay contents), physical properties (porosity, water content, bulk density, grain density and shear strength), and acoustic properties (compressional wave velocity and attenuation). We conducted mapping the distribution of sediment texture, each physical properties, and compressional wave velocity. According to the distribution map of sediment texture, the inner shelf area is consists of fine-grained sediments that are interpreted as recent sediments deposited under the present environment condition. Ulleung Basin also dominated fine-grained sediments consist of hemi-pelagic mud. On the mid-shelf, fine materials are mixed with fine-grained sediments and relict coarse sediments. Some part of the relict sediments on the mid-shelf were continuously reworked under the present environmental conditions forming the palimpsest sediments. The outer shelf area is composed of very coarse-grained sediments that are considered relict sediments deposited during the last glacial periods when the sea level was lower than the present. Based on geoacoustic property analyzed from this study, the study area is divided into five different geoacoustic provinces: (1) Province I is composed of muddy sediments that are directly affected by the Nakdong River discharge (1486 m/s, 8.1Φ, 1.32 g/cm3, and 80 %), (2) Province II is generally characterized by hemi-pelagic muds and partially mixed with intermittent sandy sediments originated from the outer shelf and upper slope (1495 m/s, 8.4Φ, 1.27 g/cm3, and 82 %), (3) Province III is comprised of muddy sand sediments that are corresponding to the boundary between recent sediments and relict sediments (1539 m/s, 5.8Φ, 1.52 g/cm3, and 69 %), (4) Province IV is dominated by coarse-grained relict sediments

  2. 3. SANDY RIVER (STARK ST.) BRIDGE, SOUTH END, LOOKING 295 ...

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

    3. SANDY RIVER (STARK ST.) BRIDGE, SOUTH END, LOOKING 295 DEGREES WEST-SOUTHWEST. - Historic Columbia River Highway, Stark Street Bridge, Spanning Sandy River on Stark Street at Historic Columbia River Highway, Troutdale, Multnomah County, OR

  3. 1. SANDY RIVER (STARK ST.) BRIDGE, NORTH END, LOOKING 135 ...

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

    1. SANDY RIVER (STARK ST.) BRIDGE, NORTH END, LOOKING 135 DEGREES SOUTHEAST. - Historic Columbia River Highway, Stark Street Bridge, Spanning Sandy River on Stark Street at Historic Columbia River Highway, Troutdale, Multnomah County, OR

  4. 5. SANDY RIVER (STARK ST.) BRIDGE, EAST ELEVATION, LOOKING 194 ...

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

    5. SANDY RIVER (STARK ST.) BRIDGE, EAST ELEVATION, LOOKING 194 DEGREES SOUTH. - Historic Columbia River Highway, Stark Street Bridge, Spanning Sandy River on Stark Street at Historic Columbia River Highway, Troutdale, Multnomah County, OR

  5. 4. SANDY RIVER (STARK ST.) BRIDGE, WEST ELEVATION, LOOKING 118 ...

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

    4. SANDY RIVER (STARK ST.) BRIDGE, WEST ELEVATION, LOOKING 118 DEGREES EAST-SOUTHEAST. - Historic Columbia River Highway, Stark Street Bridge, Spanning Sandy River on Stark Street at Historic Columbia River Highway, Troutdale, Multnomah County, OR

  6. 2. SANDY RIVER (STARK ST.) BRIDGE, NORTH END, LOOKING 163 ...

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

    2. SANDY RIVER (STARK ST.) BRIDGE, NORTH END, LOOKING 163 DEGREES SOUTH. - Historic Columbia River Highway, Stark Street Bridge, Spanning Sandy River on Stark Street at Historic Columbia River Highway, Troutdale, Multnomah County, OR

  7. A Study of Sandy Beach Zonation.

    ERIC Educational Resources Information Center

    Alexander, Steve K.

    1991-01-01

    Describes the study of sandy beach zonations as a seashore activity for either high school or lower-level college courses in biology, ecology, or marine biology. Students first draw a profile of a beach scene and then collect specimens from the zones of the shore. In a laboratory, students identify their specimens and relate them to the beach…

  8. Post-Sandy, Schools Claw Back

    ERIC Educational Resources Information Center

    Maxwell, Lesli A.

    2012-01-01

    David Weiss, the superintendent in Long Beach, N.Y., wrestled with a slew of considerations last week as he weighed when to restart school, nine days after Hurricane Sandy wrecked his community. Just one of seven buildings had most of the essentials: electricity, heat, working fire alarms, sewage, and food. And, with many students and staff…

  9. Operational Group Sandy technical progress report

    USGS Publications Warehouse

    Department of the Interior Strategic Science Group

    2013-01-01

    This report documents results from the March 2013 deployment of the OGS. It includes background information on Hurricane Sandy and the federal response; the OGS methodology; scenarios for Hurricane Sandy’s impact on coastal communities and urban ecosystems; potential interventions to improve regional resilience to future major storms; a discussion of scenario results; and lessons learned about the OGS process.

  10. Sediment trap efficiency of paddy fields at the watershed scale in a mountainous catchment in Northwest Vietnam

    NASA Astrophysics Data System (ADS)

    Slaets, J. I. F.; Schmitter, P.; Hilger, T.; Vien, T. D.; Cadisch, G.

    2015-12-01

    Composite agricultural systems with permanent maize cultivation in the uplands and irrigated rice in the valleys are very common in mountainous Southeast Asia. The soil loss and fertility decline of the upland fields is well documented, but little is known about reallocation of these sediments within the landscape. In this study, a turbidity-based linear mixed model was used to quantify sediment inputs, from surface reservoir irrigation water and from direct overland flow, into a paddy area of 13 hectares. Simultaneously, the sediment load exported from the rice fields was determined. Mid-infrared spectroscopy was applied to analyze sediment particle size. Our results showed that per year, 64 Mg ha-1 of sediments were imported into paddy fields, of which around 75 % were delivered by irrigation water and the remainder by direct overland flow during rainfall events. Overland flow contributed one third of the received sandy fraction, while irrigated sediments were predominantly silty. Overall, rice fields were a net sink for sediments, trapping 28 Mg ha-1 a-1 or almost half of total sediment inputs. As paddy outflow consisted almost exclusively of silt- and clay-sized material, 24 Mg ha-1 a-1 of the trapped amount of sediment was estimated to be sandy. Under continued intensive upland maize cultivation, such a sustained input of coarse material could jeopardize paddy soil fertility, puddling capacity and ultimately also food security of the inhabitants of these mountainous areas. Preventing direct overland flow from entering the paddy fields, however, could reduce sand inputs by up to 34 %.

  11. Sediment trap efficiency of paddy fields at the watershed scale in a mountainous catchment in northwest Vietnam

    NASA Astrophysics Data System (ADS)

    Slaets, Johanna I. F.; Schmitter, Petra; Hilger, Thomas; Vien, Tran Duc; Cadisch, Georg

    2016-06-01

    Composite agricultural systems with permanent maize cultivation in the uplands and irrigated rice in the valleys are very common in mountainous southeast Asia. The soil loss and fertility decline of the upland fields is well documented, but little is known about reallocation of these sediments within the landscape. In this study, a turbidity-based linear mixed model was used to quantify sediment inputs, from surface reservoir irrigation water and from direct overland flow, into a paddy area of 13 ha. Simultaneously, the sediment load exported from the rice fields was determined. Mid-infrared spectroscopy was applied to analyze sediment particle size. Our results showed that per year, 64 Mg ha-1 of sediments were imported into paddy fields, of which around 75 % were delivered by irrigation water and the remainder by direct overland flow during rainfall events. Overland flow contributed one-third of the received sandy fraction, while irrigated sediments were predominantly silty. Overall, rice fields were a net sink for sediments, trapping 28 Mg ha-1 a-1 or almost half of total sediment inputs. As paddy outflow consisted almost exclusively of silt- and clay-sized material, 24 Mg ha-1 a-1 of the trapped amount of sediment was estimated to be sandy. Under continued intensive upland maize cultivation, such a sustained input of coarse material could jeopardize paddy soil fertility, puddling capacity and ultimately food security of the inhabitants of these mountainous areas. Preventing direct overland flow from entering the paddy fields, however, could reduce sand inputs by up to 34 %.

  12. Comparison of instream methods for measuring hydraulic conductivity in sandy streambeds

    USGS Publications Warehouse

    Landon, M.K.; Rus, D.L.; Edwin, Harvey F.

    2001-01-01

    Streambed hydraulic conductivity (K) values were determined at seven stream transects in the Platte River Basin in Nebraska using different instream measurement techniques. Values were compared to determine the most appropriate technique(s) for use in sandy streambeds. Values of K determined from field falling- and constant-head permeameter tests analyzed using the Darcy equation decreased as permeameter diameter increased. Seepage meters coupled with hydraulic gradient measurements failed to yield K values in 40% of the trials. Consequently, Darcy permeameter and seepage meter tests were not preferred approaches. In the upper 0.25 m of the streambed, field falling- and constant-head permeameter tests analyzed with the Hvorslev solution generally had similar K values that were significantly greater than those determined using the Hazen grain-size, Bouwer and Rice slug test for anisotropic and isotropic conditions, and Alyamani and Sen grain-size methods; median differences between these tests and the Hvorslev falling-head 60 cm diameter permeameter were about 8, 9, 17, and 35 m/day, respectively. The Hvorslev falling-head permeameter test is considered the most robust method for measuring K of the upper 0.25 m of the streambed because of the inherent limitations of the empirical grain-size methods and less sediment disturbance for permeameter than slug tests. However, lateral variability in K along transects on the Platte, North Platte, and Wood Rivers was greater than variability in K between valid permeameter, grain-size, or slug tests, indicating that the method used may matter less than making enough measurements to characterize spatial variability adequately. At the Platte River tributary sites, the upper 0.3 m of the streambed typically had greater K than sediment located 0.3 to 2.5 m below the streambed surface, indicating that deposits below the streambed may limit ground water/surface water fluxes. The Hvorslev permeameter tests are not a practical

  13. Disentangling Diversity Patterns in Sandy Beaches along Environmental Gradients

    PubMed Central

    Barboza, Francisco R.; Gómez, Julio; Lercari, Diego; Defeo, Omar

    2012-01-01

    Species richness in sandy beaches is strongly affected by concurrent variations in morphodynamics and salinity. However, as in other ecosystems, different groups of species may exhibit contrasting patterns in response to these environmental variables, which would be obscured if only aggregate richness is considered. Deconstructing biodiversity, i.e. considering richness patterns separately for different groups of species according to their taxonomic affiliation, dispersal mode or mobility, could provide a more complete understanding about factors that drive species richness patterns. This study analyzed macroscale variations in species richness at 16 Uruguayan sandy beaches with different morphodynamics, distributed along the estuarine gradient generated by the Rio de la Plata over a 2 year period. Species richness estimates were deconstructed to discriminate among taxonomic groups, supralittoral and intertidal forms, and groups with different feeding habits and development modes. Species richness was lowest at intermediate salinities, increasing towards oceanic and inner estuarine conditions, mainly following the patterns shown for intertidal forms. Moreover, there was a differential tolerance to salinity changes according to the habitat occupied and development mode, which determines the degree of sensitivity of faunal groups to osmotic stress. Generalized (additive and linear) mixed models showed a clear increase of species richness towards dissipative beaches. All taxonomic categories exhibited the same trend, even though responses to grain size and beach slope were less marked for crustaceans and insects than for molluscs or polychaetes. However, supralittoral crustaceans exhibited the opposite trend. Feeding groups decreased from dissipative to reflective systems, deposit feeders being virtually absent in the latter. This deconstructive approach highlights the relevance of life history strategies in structuring communities, highlighting the relative

  14. Disentangling diversity patterns in sandy beaches along environmental gradients.

    PubMed

    Barboza, Francisco R; Gómez, Julio; Lercari, Diego; Defeo, Omar

    2012-01-01

    Species richness in sandy beaches is strongly affected by concurrent variations in morphodynamics and salinity. However, as in other ecosystems, different groups of species may exhibit contrasting patterns in response to these environmental variables, which would be obscured if only aggregate richness is considered. Deconstructing biodiversity, i.e. considering richness patterns separately for different groups of species according to their taxonomic affiliation, dispersal mode or mobility, could provide a more complete understanding about factors that drive species richness patterns. This study analyzed macroscale variations in species richness at 16 Uruguayan sandy beaches with different morphodynamics, distributed along the estuarine gradient generated by the Rio de la Plata over a 2 year period. Species richness estimates were deconstructed to discriminate among taxonomic groups, supralittoral and intertidal forms, and groups with different feeding habits and development modes. Species richness was lowest at intermediate salinities, increasing towards oceanic and inner estuarine conditions, mainly following the patterns shown for intertidal forms. Moreover, there was a differential tolerance to salinity changes according to the habitat occupied and development mode, which determines the degree of sensitivity of faunal groups to osmotic stress. Generalized (additive and linear) mixed models showed a clear increase of species richness towards dissipative beaches. All taxonomic categories exhibited the same trend, even though responses to grain size and beach slope were less marked for crustaceans and insects than for molluscs or polychaetes. However, supralittoral crustaceans exhibited the opposite trend. Feeding groups decreased from dissipative to reflective systems, deposit feeders being virtually absent in the latter. This deconstructive approach highlights the relevance of life history strategies in structuring communities, highlighting the relative

  15. 78 FR 46999 - Additional Waivers and Alternative Requirements for Hurricane Sandy Grantees in Receipt of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-02

    ... impacted and distressed areas declared a major disaster due to Hurricane Sandy (see 78 FR 14329, published... notice published March 5, 2013 (78 FR 14329), the Department allocated $5.4 billion after analyzing the... April 19, 2013 (78 FR 23578). This notice provides additional waivers and alternative requirements...

  16. INNOVATIVE TECHNOLOGY VERIFICATION REPORT XRF TECHNOLOGIES FOR MEASURING TRACE ELEMENTS IN SOIL AND SEDIMENT OXFORD X-MTE 3000TX XRF ANALYZER

    EPA Science Inventory

    The Elvatech, Ltd. ElvaX (ElvaX) x-ray fluorescence (XRF) analyzer distributed in the United States by Xcalibur XRF Services (Xcalibur), was demonstrated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program. The field por...

  17. INNOVATIVE TECHNOLOGY VERIFICATION REPORT XRF TECHNOLOGIES FOR MEASURING TRACE ELEMENTS IN SOIL AND SEDIMENT INNOV-X XT400 SERIES XRF ANALYZER

    EPA Science Inventory

    The Innov-X Systems (Innov-X) XT400 series (XT400) x-ray flurescence (XRF) analyzer was demonstrated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program. The demonstration was designed to collect reliable performance and...

  18. The North Patagonian orogenic front and related foreland evolution during the Miocene, analyzed from synorogenic sedimentation and U/Pb dating (˜42°S)

    NASA Astrophysics Data System (ADS)

    Ramos, Miguel E.; Tobal, Jonathan E.; Sagripanti, Lucía; Folguera, Andrés; Orts, Darío L.; Giménez, Mario; Ramos, Victor A.

    2015-12-01

    Miocene sedimentary successions of the Ñirihuau and Collón Cura formations east of the El Maitén Belt constitute a partial record of the Andean exhumation, defining a synorogenic infill of the Ñirihuau Basin in the foothills of the North Patagonian fold and thrust belt. Gravimetric and seismic data allow recognizing the internal arrangement and geometry of these depocenters that host both units, separating a synextensional section previous to the Andean development at these latitudes, from a series of syncontractional units above. A series of progressive unconformities in the upper terms shows the synorogenic character of these units corresponding to the different pulses of deformation that occurred during the middle Miocene. New U-Pb ages constrain these pulses to the ˜13.5-12.9 Ma interval and allow reconstructing the tectonic history of this region based on the detrital zircon source populations. The U-Pb maximum ages of sedimentation give to the Ñirihuau Formation in particular a younger age than previously assumed. Additionally, synsedimentary deformation in strata of the upper exposures of the Collón Cura Formation associated with contractional structures and U-Pb ages allow identifying a younger paleoseismogenic pulse in ˜11.3 Ma. Thus, based on these data and a compilation of previous datasets, a tectonic evolution is proposed characterized by a contractional episode that migrated eastwardly since ˜19 to 15 Ma producing the Gastre broken foreland and then retracted to the eastern North Patagonian Precordillera, where out-of-sequence thrusts cannibalized the wedge top zone in the El Maitén belt at ˜13.5-11.3 Ma.

  19. Low faunal diversity on Maltese sandy beaches: fact or artefact?

    NASA Astrophysics Data System (ADS)

    Deidun, Alan; Azzopardi, Marthese; Saliba, Stephen; Schembri, Patrick J.

    2003-10-01

    Eight sandy beaches on Malta and two on Gozo were sampled for macrofauna to test the hypothesis that Maltese beaches have an intrinsically low diversity. Stations distributed in the supralittoral (dry zone), mediolittoral (wet zone) and upper infralittoral (submerged zone to 1 m water depth) were sampled by sieving core samples and standardised searching during daytime, and pitfall trapping and standardised sweeping of the water column using a hand-net at night, as appropriate. Physical parameters of the sediment were measured and human occupancy of the beaches was estimated. From the supralittoral and mediolittoral, 39 species represented by 1584 individuals were collected by the combined techniques of pitfall trapping, sieving and standard searching. For Ramla beach, which had the highest diversity, 267 individuals representing 25 infaunal species were collected by sieving from a combined volume of 1.175 m 3 of sand, and 149 individuals representing 28 epifaunal species were collected by standardised searching from a combined area of 700 m 2 of sand during two winter and two summer sampling sessions between 1992 and 1993. For nine other beaches sampled during the summer of 2000, only six macrofaunal species were collected from core samples, with overall population densities ranging from 4.13 to 45.45 individuals m -2. Only 92 individuals belonging to 12 species were collected by hand-net from the uppermost infralittoral of five beaches sampled using this method during the summer of 2000. Taxa of gastropods, bivalves, decapods, mysids and staphylinid beetles generally abundant on Mediterranean sandy beaches, were entirely absent from the beaches sampled. Few correlations that could explain the impoverishment of Maltese sandy beaches were found between physical parameters and faunal abundances, and other factors such as inadequate sampling effort, human disturbance and marine pollution were also excluded; however, seasonally biased sampling may partly explain the

  20. Responses of soil fungal community to the sandy grassland restoration in Horqin Sandy Land, northern China.

    PubMed

    Wang, Shao-Kun; Zuo, Xiao-An; Zhao, Xue-Yong; Li, Yu-Qiang; Zhou, Xin; Lv, Peng; Luo, Yong-Qing; Yun, Jian-Ying

    2016-01-01

    Sandy grassland restoration is a vital process including re-structure of soils, restoration of vegetation, and soil functioning in arid and semi-arid regions. Soil fungal community is a complex and critical component of soil functioning and ecological balance due to its roles in organic matter decomposition and nutrient cycling following sandy grassland restoration. In this study, soil fungal community and its relationship with environmental factors were examined along a habitat gradient of sandy grassland restoration: mobile dunes (MD), semi-fixed dunes (SFD), fixed dunes (FD), and grassland (G). It was found that species abundance, richness, and diversity of fungal community increased along with the sandy grassland restoration. The sequences analysis suggested that most of the fungal species (68.4 %) belonged to the phylum of Ascomycota. The three predominant fungal species were Pleospora herbarum, Wickerhamomyces anomalus, and Deconica Montana, accounting for more than one fourth of all the 38 species. Geranomyces variabilis was the subdominant species in MD, Pseudogymnoascus destructans and Mortierella alpine were the subdominant species in SFD, and P. destructans and Fungi incertae sedis were the dominant species in FD and G. The result from redundancy analysis (RDA) and stepwise regression analysis indicated that the vegetation characteristics and soil properties explain a significant proportion of the variation in the fungal community, and aboveground biomass and C:N ratio are the key factors to determine soil fungal community composition during sandy grassland restoration. It was suggested that the restoration of sandy grassland combined with vegetation and soil properties improved the soil fungal diversity. Also, the dominant species was found to be alternative following the restoration of sandy grassland ecosystems. PMID:26661957

  1. High-Resolution Sedimentation Rates at IODP Sites U1424 and U1427 since the late Pliocene from spectral-analyzing GRA Bulk Density and RGB Color Profiles

    NASA Astrophysics Data System (ADS)

    Gorgas, Thomas; Irino, Tomohisa; Tada, Ryuji

    2016-04-01

    Sedimentation Rates (SRs) for IODP Sites U1424 (lat/lon coordinates: 40o11.40'N, 138o13.90'E; water depth: 2808 mbsl) and U1427 (lat/lon coordinates: 35o57.92'N, 134o26.06'E; water depth: 330 mbsl) were calculated by performing spectral analysis in the depth domain on both RGB color and Gamma-Ray-Attenuation (GRA) bulk density data. Inversion and integration of SRs versus depth from spectral analysis yielded detailed SR profiles in both time and depth domains. Our results show a greater variability in calculated SRs and differed from those established through coarse-scaled biostratigraphy and paleo-magnetic data. Our data analyses produces pulses of distinct high SRs for certain depth/age intervals at both sites, with time lags for such features possibly due to variable oceanographic conditions near-shore for Site U1427 versus those at Site U1424 further offshore. Both GRA and RGB profiles reveal a distinct periodicity in the waveband of Milankovitch cycles and other prominent periodicities in the 10-to-1ky period range. This observation suggests climate variabilities and trends in SRs responding to insolation patterns during the past 1 Myr at both sites and extending to 4.5 Myr for Site U1424. With only few identified eccentricity (100ky) cycle segments throughout the entire normalized spectral amplitude profile, our high-resolution Age-Depth model was tuned to obliquity (41ky) and precessional (19-23ky) cycles to achieving a strong fit with corresponding low-resolution models based on biostratigraphy, paleo-magnetic and, at least for Site U1424, augmenting volcanostratigraphy data. According to our Age-Depth models, relatively low SRs occur when evolutive amplitude spectra are dominated by periods in the range of obliquity and eccentricity. In contrast, significant SR peaks at both sites often occur when strong precessional amplitudes coexist with all other cycles. Lower SRs at Site U1424 have been interpreted to reflect a decrease in diatom flux and relative

  2. Laboratory Study of Quaternary Sediment Resistivity Related to Groundwater Contamination at Mae-Hia Landfill, Mueang District, Chiang Mai Province

    NASA Astrophysics Data System (ADS)

    Sichan, N.

    2007-12-01

    This study was aimed to understand the nature of the resistivity value of the sediment when it is contaminated, in order to use the information solving the obscure interpretation in the field. The pilot laboratory experiments were designed to simulate various degree of contamination and degree of saturation then observe the resulting changes in resistivity. The study was expected to get a better understanding of how various physical parameters effect the resistivity values in term of mathematic function. And also expected to apply those obtained function to a practical quantitatively interpretation. The sediment underlying the Mae-Hia Landfill consists of clay-rich material, with interfingerings of colluvium and sandy alluvium. A systematic study identified four kinds of sediment, sand, clayey sand, sandy clay, and clay. Representative sediment and leachate samples were taken from the field and returned to the laboratory. Both the physical and chemical properties of the sediments and leachate were analyzed to delineate the necessary parameters that could be used in Archie's equation. Sediment samples were mixed with various concentration of leachate solutions. Then the resistivity values were measured at various controlled steps in the saturation degree in a well- calibrated six-electrode model resistivity box. The measured resistivity values for sand, clayey sand, sandy clay when fully and partly saturated were collected, then plotted and fitted to Archie's equation, to obtain a mathematical relationship between bulk resistivity, porosity, saturation degree and resistivity of pore fluid. The results fit well to Archie's equation, and it was possible to determine all the unknown parameters representative of the sediment samples. For sand, clayey sand, sandy clay, and clay, the formation resistivity factors (F) are 2.90, 5.77, 7.85, and 7.85 with the products of cementation factor (m) and the pore geometry factors (a) (in term of -am) are 1.49, -1.63, -1.92, -2

  3. Spatial Patterns and Natural Recruitment of Native Shrubs in a Semi-arid Sandy Land

    PubMed Central

    Wu, Bo; Yang, Hongxiao

    2013-01-01

    Passive restoration depending on native shrubs is an attractive approach for restoring desertified landscapes in semi-arid sandy regions. We sought to understand the relationships between spatial patterns of native shrubs and their survival ability in sandy environments. Furthermore, we applied our results to better understand whether passive restoration is feasible for desertified landscapes in semi-arid sandy regions. The study was conducted in the semi-arid Mu Us sandy land of northern China with the native shrub Artemisia ordosica. We analyzed population structures and patterns of A. ordosica at the edges and centers of land patches where sand was stabilized by A. ordosica-dominated vegetation. Saplings were more aggregated than adults, and both were more aggregated at the patch edges than at the patch centers. At the patch edges, spatial association of the saplings with the adults was mostly positive at distances 0.3–6.6 m, and turned from positive to neutral, and even negative, at other distances. At the patch centers, the saplings were spaced almost randomly around the adults, and their distances from the adults did not seem to affect their locations. A greater number of A. ordosica individuals emerged at the patch edges than at the patch centers. Such patterns may have resulted from their integrative adjustment to specific conditions of soil water supply and sand drift intensity. These findings suggest that in semi-arid sandy regions, native shrubs that are well-adapted to local environments may serve as low-cost and competent ecological engineers that can promote the passive restoration of surrounding patches of mobile sandy land. PMID:23505489

  4. Intermittent turbulent events over sandy current ripples: a motion-picture analysis of flume experiments

    NASA Astrophysics Data System (ADS)

    Ha, H. K.; Chough, S. K.

    2003-10-01

    A series of laboratory flume experiments was conducted in order to elucidate sediment transport processes over sandy current ripples. Instantaneous cinematography, capable of recording up to 30 frames per second, was employed to trace the coherent trajectories of the sediment particles and flow. Analysis of channel side-view images suggests that sediment behaviour over a fully developed current ripple can be categorized as distinct stages on both stoss and lee sides. Near the reattachment point on the stoss side, sediment particles exhibit the following intermittent but coherent motions: (1) impact of sediment-laden fluid on the reattachment point; (2) entrainment of particles; (3) spiral-like turbulent motion; and (4) downstream dissipation of particles. The sequential sediment behaviour is called micro-scale kolk, which is a key mechanism responsible for turbulent sediment entrainment over current ripples. The salient features of boil were not observed. In the crest and lee side region, sequential images show the following characteristics: (1) detachment of particles and fluid at the crest; (2) entrainment and shielding of particles; (3) avalanching and rolling of free-shear layer; and (4) downstream dissipation and recreation of a lee face. Segregation of heavy minerals was accomplished by successive avalanches along the lee slope and mixing vortices in the separation cell.

  5. BIOREMEDIATION OF OIL-CONTAMINATED FINE SEDIMENTS.

    EPA Science Inventory

    Bioremediation of oil contamination has been shown to be effective for cobble and sandy shorelines. To assess the operational limitations of this technology, this project studied its potential to treat buried oil in fine sediments. The effectiveness of bioremediation by nutrient ...

  6. Atmospheric significance of aeolian salts in the sandy deserts of northwestern China

    NASA Astrophysics Data System (ADS)

    Zhu, B.-Q.

    2015-12-01

    Large sandy deserts in the middle latitudes of northwestern China were investigated for soluble salt variations in modern and ancient aeolian sediments, aiming to explore the environmental significance of "aeolian salts". Results revealed that aeolian salt variations have a clear relationship with the changing meridional and zonal gradients of the desert locations and the aeolian differentiation effect, but are weakly linked to local geological conditions. It suggests that the natural system of aeolian salts is hydrologically open and the chemistry of the parent brines are different from that predicted for hydrologically closed systems. Atmospheric depositions of water-soluble chemical species are an important process/source contributing to aeolian salt. Sequential variations of soluble salts in sedimentary profiles interbedded with aeolian and non-aeolian deposits and their palaeoenvironmental implications in the hinterland areas of these deserts were further evaluated, based on the constraints of OSL dating and radiocarbon dating data. The results indicate that the inorganic salts may be a latent geoproxy in revealing regional palaeoclimatic changes in desert areas for the sediments deposited under onefold depositional environment, but the interpretation should be more careful for the sediments deposited under diverse depositional conditions. This study presents the evidence of atmospheric origin of aeolian salt in sandy deserts, with limited climatic significance in palaeoenvironmental reconstruction.

  7. Atmospheric significance of aeolian salts in the sandy deserts of northwestern China

    NASA Astrophysics Data System (ADS)

    Zhu, B.-Q.

    2016-02-01

    Large sandy deserts in the middle latitudes of northwestern China were investigated for soluble salt variations in modern and ancient aeolian sediments, aiming to explore the environmental significance of "aeolian salts". Results revealed that aeolian salt variations have a clear relationship with the changing meridional and zonal gradients of the desert locations and the aeolian differentiation effect, but are weakly linked to local geological conditions. Atmospheric depositions of water-soluble chemical species are an important process/source contributing to aeolian salt. Sequential variations of soluble salts in sedimentary profiles interbedded with aeolian and non-aeolian deposits and their palaeoenvironmental implications in the hinterland areas of these deserts were further evaluated, based on the constraints of OSL dating and radiocarbon dating data. The results indicate that inorganic salts may be a latent geoproxy in revealing regional palaeoclimatic changes in desert areas for sediments deposited under a single depositional environment, but the interpretation should be more cautious for sediments deposited under diverse depositional conditions. This study presents evidence of the atmospheric origin of aeolian salt in sandy deserts, with limited climatic significance in palaeoenvironmental reconstruction.

  8. Threats to sandy beach ecosystems: A review

    NASA Astrophysics Data System (ADS)

    Defeo, Omar; McLachlan, Anton; Schoeman, David S.; Schlacher, Thomas A.; Dugan, Jenifer; Jones, Alan; Lastra, Mariano; Scapini, Felicita

    2009-01-01

    We provide a brief synopsis of the unique physical and ecological attributes of sandy beach ecosystems and review the main anthropogenic pressures acting on the world's single largest type of open shoreline. Threats to beaches arise from a range of stressors which span a spectrum of impact scales from localised effects (e.g. trampling) to a truly global reach (e.g. sea-level rise). These pressures act at multiple temporal and spatial scales, translating into ecological impacts that are manifested across several dimensions in time and space so that today almost every beach on every coastline is threatened by human activities. Press disturbances (whatever the impact source involved) are becoming increasingly common, operating on time scales of years to decades. However, long-term data sets that describe either the natural dynamics of beach systems or the human impacts on beaches are scarce and fragmentary. A top priority is to implement long-term field experiments and monitoring programmes that quantify the dynamics of key ecological attributes on sandy beaches. Because of the inertia associated with global climate change and human population growth, no realistic management scenario will alleviate these threats in the short term. The immediate priority is to avoid further development of coastal areas likely to be directly impacted by retreating shorelines. There is also scope for improvement in experimental design to better distinguish natural variability from anthropogenic impacts. Sea-level rise and other effects of global warming are expected to intensify other anthropogenic pressures, and could cause unprecedented ecological impacts. The definition of the relevant scales of analysis, which will vary according to the magnitude of the impact and the organisational level under analysis, and the recognition of a physical-biological coupling at different scales, should be included in approaches to quantify impacts. Zoning strategies and marine reserves, which have not

  9. Regime shift in sandy beach microbial communities following Deepwater Horizon oil spill remediation efforts.

    PubMed

    Engel, Annette Summers; Gupta, Axita A

    2014-01-01

    Sandy beaches support a wide variety of underappreciated biodiversity that is critical to coastal ecosystems. Prior to the 2010 Deepwater Horizon oil spill, the diversity and function of supratidal beach sediment microbial communities along Gulf of Mexico coastlines were not well understood. As such, it was unclear if microbial community compositional changes would occur following exposure to beached oil, if indigenous communities could biodegrade oil, or how cleanup efforts, such as sand washing and sediment redistribution, would impact microbial ecosystem resiliency. Transects perpendicular to the shoreline were sampled from public beaches on Grand Isle, Louisiana, and Dauphin Island, Alabama, over one year. Prior to oil coming onshore, elevated levels of bacteria associated with fecal contamination were detected (e.g., Enterobacteriales and Campylobacterales). Over time, significant shifts within major phyla were identified (e.g., Proteobacteria, Firmicutes, Actinobacteria) and fecal indicator groups were replaced by taxa affiliated with open-ocean and marine systems (e.g., Oceanospirillales, Rhodospirillales, and Rhodobacterales). These new bacterial groups included putative hydrocarbon degraders, similar to those identified near the oil plume offshore. Shifts in the microbial community composition strongly correlated to more poorly sorted sediment and grain size distributional changes. Natural oceanographic processes could not account for the disrupted sediment, especially from the backshore well above the maximum high-tide levels recorded at these sites. Sand washing and tilling occurred on both open beaches from August through at least December 2010, which were mechanisms that could replace fecal indicator groups with open-ocean groups. Consequently, remediation efforts meant to return beaches to pre-spill compositions caused a regime shift that may have added potential ecosystem function, like hydrocarbon degradation, to the sediment. Future research will

  10. Regime Shift in Sandy Beach Microbial Communities following Deepwater Horizon Oil Spill Remediation Efforts

    PubMed Central

    Engel, Annette Summers; Gupta, Axita A.

    2014-01-01

    Sandy beaches support a wide variety of underappreciated biodiversity that is critical to coastal ecosystems. Prior to the 2010 Deepwater Horizon oil spill, the diversity and function of supratidal beach sediment microbial communities along Gulf of Mexico coastlines were not well understood. As such, it was unclear if microbial community compositional changes would occur following exposure to beached oil, if indigenous communities could biodegrade oil, or how cleanup efforts, such as sand washing and sediment redistribution, would impact microbial ecosystem resiliency. Transects perpendicular to the shoreline were sampled from public beaches on Grand Isle, Louisiana, and Dauphin Island, Alabama, over one year. Prior to oil coming onshore, elevated levels of bacteria associated with fecal contamination were detected (e.g., Enterobacteriales and Campylobacterales). Over time, significant shifts within major phyla were identified (e.g., Proteobacteria, Firmicutes, Actinobacteria) and fecal indicator groups were replaced by taxa affiliated with open-ocean and marine systems (e.g., Oceanospirillales, Rhodospirillales, and Rhodobacterales). These new bacterial groups included putative hydrocarbon degraders, similar to those identified near the oil plume offshore. Shifts in the microbial community composition strongly correlated to more poorly sorted sediment and grain size distributional changes. Natural oceanographic processes could not account for the disrupted sediment, especially from the backshore well above the maximum high-tide levels recorded at these sites. Sand washing and tilling occurred on both open beaches from August through at least December 2010, which were mechanisms that could replace fecal indicator groups with open-ocean groups. Consequently, remediation efforts meant to return beaches to pre-spill compositions caused a regime shift that may have added potential ecosystem function, like hydrocarbon degradation, to the sediment. Future research will

  11. Mediterranean undercurrent sandy contourites, Gulf of Cadiz, Spain

    USGS Publications Warehouse

    Hans, Nelson C.; Baraza, J.; Maldonado, A.

    1993-01-01

    and contourite deposits exhibit reverse graded bedding and sharp upper bed contacts in coarse-grained layers, low deposition rates, and a regional pattern of bedform zones, textural variation, and compositional gradation. The surface sandy contourite layer of 0.2-1.2 m thickness that covers the Gulf of Cadiz slope has formed during the present Holocene high sea level because high sea level results in maximum water depth over the Gibraltar sill and full development of the Mediterranean undercurrent. The late Pleistocene age of the mud underlying the surface sand sheet correlates with the age of the last sea-level lowstand and apparent weak Mediterranean undercurrent development. Thus, the cyclic deposition of sand or mud layers and contourite or drape sequences appear to be related to late Pliocene and Quaternary sea-level changes and Mediterranean water circulation patterns. Since its Pliocene origin, the contourite sequence has had low deposition rates of < 5 cm/1000y on the upper slope and < 13 cm/1000y in the middle slope sediment drift. ?? 1993.

  12. Mediterranean undercurrent sandy contourites, Gulf of Cadiz, Spain

    NASA Astrophysics Data System (ADS)

    Hans Nelson, C.; Baraza, Jesús; Maldonado, Andrés

    1993-01-01

    valley and contourite deposits exhibit reverse graded bedding and sharp upper bed contacts in coarse-grained layers, low deposition rates, and a regional pattern of bedform zones, textural variation, and compositional gradation. The surface sandy contourite layer of 0.2-1.2 m thickness that covers the Gulf of Cadiz slope has formed during the present Holocene high sea level because high sea level results in maximum water depth over the Gibraltar sill and full development of the Mediterranean undercurrent. The late Pleistocene age of the mud underlying the surface sand sheet correlates with the age of the last sea-level lowstand and apparent weak Mediterranean undercurrent development. Thus, the cyclic deposition of sand or mud layers and contourite or drape sequences appear to be related to late Pliocene and Quaternary sea-level changes and Mediterranean water circulation patterns. Since its Pliocene origin, the contourite sequence has had low deposition rates of < 5 cm/1000y on the upper slope and < 13 cm/1000y in the middle slope sediment drift.

  13. Cohesive Sediments in Groyne Fields along the Elbe River

    NASA Astrophysics Data System (ADS)

    Hillebrand, G.; Heininger, P.; Krämer, T.; Möhlenkamp, C.; Pelzer, J.; Schwandt, D.; Claus, E.

    2012-04-01

    The ICPER aims at establishing a sediment management concept both in terms of quantity and quality by 2013. To this end, the key processes of sediment transport and budget have to be defined under regular and under extreme conditions. Sediment budgets in regulated rivers are strongly influenced by lateral exchange processes. This study focuses on the function of groyne fields acting as source and sink for cohesive sediments and particle-bound contaminants along the Elbe. One specific aim is to assess the amount of erodible contaminated sediments within the groyne fields as basis for establishing a sediment management plan. In several field campaigns in 2010 and 2011, 282 groyne fields between Elbe-km 129 and 578 were probed by sounding rods, push core samplers and van Veen grabs to estimate the sediment composition of the deposits. The sediments were subjectively classified on site as "gravel", "sand" or "mud" and the total amount of mud per groyne field was categorized as "much", "little" or "none". 33 groyne fields were identified as gravelly, 118 as sandy and 92 as muddy. Mud content of 73 groyne fields was considered high, low in 59, no mud was found in 128 groyne fields. The estimated sediment inventory was analyzed for possible correlations to a set of parameters including geometric characteristics of the groynes and the groyne fields, river alignment or the grain size distribution of the adjacent main channel. As an example, strong interdependency was found for groyne fields with high mud content between conventional groyne structures when they were connected to backwaters and exhibited longitudinal ridges within the groyne field. For validation concerning the different subjective estimates of all the research groups involved in the field campaigns, group-specific subsets were analyzed and no significant deviation in the observed correlations were found. The analysis is used to extrapolate the findings to the whole river reach between Elbe-km 0 and 585

  14. Characteristics of a sandy depositional lobe on the outer Mississippi fan from SeaMARC IA sidescan sonar images

    USGS Publications Warehouse

    Twichell, David C.; Schwab, William C.; Nelson, C. Hans; Kenyon, Neil H.; Lee, Homa J.

    1992-01-01

    SeaMARC IA sidescan sonar images of the distal reaches of a depositional lobe on the Mississippi Fan show that channelized rather than unconfined transport was the dominant transport mechanism for coarse-grained sediment during the formation of this part of the deep-sea fan. Overbank sheet flow of sands was not an important process in the transport and deposition of the sandy and silty sediment found on this fan. The dendritic distributary pattern and the high order of splaying of the channels, only one of which appears to have been active at a time, suggest that coarse-grained deposits on this fan are laterally discontinuous.

  15. Characteristics of a sandy depositional lobe on the outer Mississippi fan from SeaMARC IA sidescan sonar images

    SciTech Connect

    Twichell, D.C.; Schwab, W.C. ); Nelson, C.H.; Lee, H.J. ); Kenyon, N.H. )

    1992-08-01

    SeaMARC IA sidescan sonar images of the distal reaches of a depositional lobe on the Mississippi Fan show that channelized rather than unconfined transport was the dominant transport mechanism for coarse-grained sediment during the formation of this part of the deep-sea fan. Overbank sheet flow of sands was not an important process in the transport and deposition of the sandy and silty sediment found on this fan. The dendritic distributary pattern and the high order of splaying of the channels, only one which appears to have been active at a time, suggest that coarse-grained deposits on this fan are laterally discontinuous.

  16. 77 FR 74341 - Establishing the Hurricane Sandy Rebuilding Task Force

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-14

    ... person. (Presidential Sig.) THE WHITE HOUSE, Washington, December 7, 2012. [FR Doc. 2012-30310 Filed 12... the Hurricane Sandy Rebuilding Task Force By the authority vested in me as President by the... order establishes the Hurricane Sandy Rebuilding Task Force (Task Force) to provide the...

  17. BACTERIOPHAGE TRANSPORT IN SANDY SOIL AND FRACTURED TUFF

    EPA Science Inventory

    Bacteriophage transport was investigated in laboratory column experiments using sandy soil, a controlled field study in a sandy wash, and laboratory experiments using fractured rock. In the soil columns, the phage MS-2 exhibited significant dispersion and was excluded from 35 to ...

  18. Correlation between landscape fragmentation and sandy desertification: a case study in Horqin Sandy Land, China.

    PubMed

    Ge, Xiaodong; Dong, Kaikai; Luloff, A E; Wang, Luyao; Xiao, Jun; Wang, Shiying; Wang, Qian

    2016-01-01

    The exact roles of landscape fragmentation on sandy desertification are still not fully understood, especially with the impact of different land use types in spatial dimension. Taking patch size and shape into consideration, this paper selected the Ratio of Patch Size and the Fractal Dimension Index to establish a model that reveals the association between the area of bare sand land and the fragmentation of different land use types adjacent to bare sand land. Results indicated that (1) grass land and arable land contributed the most to landscape fragmentation processes in the regions adjacent to bare sand land during the period 1980 to 2010. Grass land occupied 54 % of the region adjacent to bare sand land in 1980. The Ratio of Patch Size of grass land decreased from 1980 to 2000 and increased after 2000. The Fractal Dimension Index of grass increased during the period 1980 to 1990 and decreased after 1990. Arable land expanded significantly during this period. The Ratio of Patch Size of arable land increased from 1980 to 1990 and decreased since 1990. The Fractal Dimension Index of arable land increased from 1990 to 2000 and decreased after 2000. (2) The Ratio of Patch Size and the Fractal Dimension Index were significantly related to the area of bare sand land. The role of landscape fragmentation was not linear to sandy desertification. There were both positive and negative effects of landscape fragmentation on sandy desertification. In 1980, the Ratio of Patch Size and the Fractal Dimension Index were negatively related to the area of bare sand land, showing that the landscape fragmentation and regularity of patches contributed to the expansion of sandy desertification. In 1990, 2000, and 2010, the Ratio of Patch Size and the Fractal Dimension Index were mostly positively related to the area of bare sand land, showing the landscape fragmentation and regularity of patches contributed to the reversion of sandy desertification in this phase. The absolute values of

  19. Setting conservation targets for sandy beach ecosystems

    NASA Astrophysics Data System (ADS)

    Harris, Linda; Nel, Ronel; Holness, Stephen; Sink, Kerry; Schoeman, David

    2014-10-01

    Representative and adequate reserve networks are key to conserving biodiversity. This begs the question, how much of which features need to be placed in protected areas? Setting specifically-derived conservation targets for most ecosystems is common practice; however, this has never been done for sandy beaches. The aims of this paper, therefore, are to propose a methodology for setting conservation targets for sandy beach ecosystems; and to pilot the proposed method using data describing biodiversity patterns and processes from microtidal beaches in South Africa. First, a classification scheme of valued features of beaches is constructed, including: biodiversity features; unique features; and important processes. Second, methodologies for setting targets for each feature under different data-availability scenarios are described. From this framework, targets are set for features characteristic of microtidal beaches in South Africa, as follows. 1) Targets for dune vegetation types were adopted from a previous assessment, and ranged 19-100%. 2) Targets for beach morphodynamic types (habitats) were set using species-area relationships (SARs). These SARs were derived from species richness data from 142 sampling events around the South African coast (extrapolated to total theoretical species richness estimates using previously-established species-accumulation curve relationships), plotted against the area of the beach (calculated from Google Earth imagery). The species-accumulation factor (z) was 0.22, suggesting a baseline habitat target of 27% is required to protect 75% of the species. This baseline target was modified by heuristic principles, based on habitat rarity and threat status, with final values ranging 27-40%. 3) Species targets were fixed at 20%, modified using heuristic principles based on endemism, threat status, and whether or not beaches play an important role in the species' life history, with targets ranging 20-100%. 4) Targets for processes and 5

  20. Three-dimensional distribution of plastic pellets in sandy beaches: shifting paradigms

    NASA Astrophysics Data System (ADS)

    Turra, Alexander; Manzano, Aruanã B.; Dias, Rodolfo Jasão S.; Mahiques, Michel M.; Barbosa, Lucas; Balthazar-Silva, Danilo; Moreira, Fabiana T.

    2014-03-01

    Plastic pellets are worldwide contaminants that accumulate in the ocean, especially in sandy beaches, where their historic standing-stock quantification relies on surface sediment samples. We demonstrated these particles present a three-dimensional instead of a simple along-across shore distribution, being found as deep as 2.0 m, with surface layers accounting for <10% of the total abundance in the sediment column. This gradient seemed to be more related to oceanographic rather than anthropic processes, suggesting a general pattern whose applicability to microplastics and sedimentary environments as a whole should be investigated. This poses criticism in the exactness of standing-stock records and demands urgent discussion of sampling protocols.

  1. Three-dimensional distribution of plastic pellets in sandy beaches: shifting paradigms

    PubMed Central

    Turra, Alexander; Manzano, Aruanã B.; Dias, Rodolfo Jasão S.; Mahiques, Michel M.; Barbosa, Lucas; Balthazar-Silva, Danilo; Moreira, Fabiana T.

    2014-01-01

    Plastic pellets are worldwide contaminants that accumulate in the ocean, especially in sandy beaches, where their historic standing-stock quantification relies on surface sediment samples. We demonstrated these particles present a three-dimensional instead of a simple along-across shore distribution, being found as deep as 2.0 m, with surface layers accounting for <10% of the total abundance in the sediment column. This gradient seemed to be more related to oceanographic rather than anthropic processes, suggesting a general pattern whose applicability to microplastics and sedimentary environments as a whole should be investigated. This poses criticism in the exactness of standing-stock records and demands urgent discussion of sampling protocols. PMID:24670631

  2. DIFFERENTIAL ANALYZER

    DOEpatents

    Sorensen, E.G.; Gordon, C.M.

    1959-02-10

    Improvements in analog eomputing machines of the class capable of evaluating differential equations, commonly termed differential analyzers, are described. In general form, the analyzer embodies a plurality of basic computer mechanisms for performing integration, multiplication, and addition, and means for directing the result of any one operation to another computer mechanism performing a further operation. In the device, numerical quantities are represented by the rotation of shafts, or the electrical equivalent of shafts.

  3. Uranium Redistribution Due to Water Table Fluctuations in Sandy Wetland Mesocosms.

    PubMed

    Gilson, Emily R; Huang, Shan; Koster van Groos, Paul G; Scheckel, Kirk G; Qafoku, Odeta; Peacock, Aaron D; Kaplan, Daniel I; Jaffé, Peter R

    2015-10-20

    To understand better the fate and stability of immobilized uranium (U) in wetland sediments, and how intermittent dry periods affect U stability, we dosed saturated sandy wetland mesocosms planted with Scirpus acutus with low levels of uranyl acetate for 4 months before imposing a short drying and rewetting period. Concentrations of U in mesocosm effluent increased after drying and rewetting, but the cumulative amount of U released following the dry period constituted less than 1% of the total U immobilized in the soil during the 4 months prior. This low level of remobilization suggests, and XANES analyses confirm, that microbial reduction was not the primary means of U immobilization, as the U immobilized in mesocosms was primarily U(VI) rather than U(IV). Drying followed by rewetting caused a redistribution of U downward in the soil profile and to root surfaces. Although the U on roots before drying was primarily associated with minerals, the U that relocated to the roots during drying and rewetting was bound diffusely. Results show that short periods of drought conditions in a sandy wetland, which expose reduced sediments to air, may impact U distribution without causing large releases of soil-bound U to surface waters. PMID:26404564

  4. Rediscovering Community—Reflections After Hurricane Sandy

    PubMed Central

    See, Sharon

    2013-01-01

    Hoboken, New Jersey, is a town of 50,000 residents located across the Hudson River from New York City. Most of Hoboken’s infrastructure was compromised during Hurricane Sandy as a result of flooding and power outages that rendered many businesses inoperable, including all of the pharmacies in town. Despite a focus on emergency preparedness since Hurricane Katrina and 9/11, there were no contingencies in place to facilitate and assess the medication needs of the community in the event of a natural disaster. This essay describes how the author rediscovered the meaning of community, and through working with colleagues in other health care disciplines and non–health care volunteers, provided care to patients in suboptimal circumstances. PMID:24218382

  5. Rediscovering community--reflections after Hurricane Sandy.

    PubMed

    See, Sharon

    2013-01-01

    Hoboken, New Jersey, is a town of 50,000 residents located across the Hudson River from New York City. Most of Hoboken's infrastructure was compromised during Hurricane Sandy as a result of flooding and power outages that rendered many businesses inoperable, including all of the pharmacies in town. Despite a focus on emergency preparedness since Hurricane Katrina and 9/11, there were no contingencies in place to facilitate and assess the medication needs of the community in the event of a natural disaster. This essay describes how the author rediscovered the meaning of community, and through working with colleagues in other health care disciplines and non-health care volunteers, provided care to patients in suboptimal circumstances. PMID:24218382

  6. Process Analyzer

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The ChemScan UV-6100 is a spectrometry system originally developed by Biotronics Technologies, Inc. under a Small Business Innovation Research (SBIR) contract. It is marketed to the water and wastewater treatment industries, replacing "grab sampling" with on-line data collection. It analyzes the light absorbance characteristics of a water sample, simultaneously detects hundreds of individual wavelengths absorbed by chemical substances in a process solution, and quantifies the information. Spectral data is then processed by ChemScan analyzer and compared with calibration files in the system's memory in order to calculate concentrations of chemical substances that cause UV light absorbance in specific patterns. Monitored substances can be analyzed for quality and quantity. Applications include detection of a variety of substances, and the information provided enables an operator to control a process more efficiently.

  7. Gas Analyzer

    NASA Technical Reports Server (NTRS)

    1989-01-01

    The M200 originated in the 1970's under an Ames Research Center/Stanford University contract to develop a small, lightweight gas analyzer for Viking Landers. Although the unit was not used on the spacecraft, it was further developed by The National Institute for Occupational Safety and Health (NIOSH). Three researchers from the project later formed Microsensor Technology, Inc. (MTI) to commercialize the analyzer. The original version (Micromonitor 500) was introduced in 1982, and the M200 in 1988. The M200, a more advanced version, features dual gas chromatograph which separate a gaseous mixture into components and measure concentrations of each gas. It is useful for monitoring gas leaks, chemical spills, etc. Many analyses are completed in less than 30 seconds, and a wide range of mixtures can be analyzed.

  8. Composition, structure and properties of sediment thermal springs of Kamchatka

    NASA Astrophysics Data System (ADS)

    Shanina, Violetta; Smolyakov, Pavel; Parfenov, Oleg

    2016-04-01

    The paper deals with the physical and mechanical properties sediment thermal fields Mutnovsky, Lower Koshelevo and Bannyh (Kamchatka). This multi-component soils, mineral and chemical composition of which depends on the formation factors (pH, temperature, salinity of water, composition and structure of the host volcanic rocks). Samples Lower Koshelevo sediment thermal sources differ in the following composition: smectite, kaolinite, kaolinite-smectite mixed-mineral. Samples of sediment thermal springs Mutnovsky volcano in accordance with the X-ray analysis has the following composition: volcanic glass, crystalline sulfur, plagioclase, smectite, illite-smectite mixed, illite, chlorite, quartz, cristobalite, pyrite, melanterite, kaolinite. Natural moisture content samples of sediment thermal springs from 45 to 121%, hygroscopic moisture content of 1.3 to 3.7%. A large amount of native sulfur (up to 92%) and the presence of amorphous material gives low values of density of solid particles (up to 2.1 g/cm3) samples Mutnovskii thermal field. The values of the density of solids sediment Koshelevo and Bannyh hot springs close to those of the main components of mineral densities (up to 2.6-3.0 g/cm3). The results of the particle size distribution and microaggregate analysis of sediment thermal springs Lower Koshelevo field shows that the predominance observed of particles with a diameter from 0.05 mm to 0.25 mm, the coefficient of soil heterogeneity heterogeneous. In the bottom sediments of the thermal springs of the volcano Mutnovsky poorly traced predominance of one faction. Most prevalent fraction with particle size 0.01 - 0.05 mm. When analyzing the content in the soil microaggregates their content is shifted towards particles with a diameter of 0.25 mm. The contents of a large number of large (1-10 mm), porous rock fragments, due to the deposition of pyroclastic material from the eruptions of the last century. Present in large amounts rounded crystals of native sulfur

  9. Blood Analyzer

    NASA Technical Reports Server (NTRS)

    1992-01-01

    In the 1970's, NASA provided funding for development of an automatic blood analyzer for Skylab at the Oak Ridge National Laboratory (ORNL). ORNL devised "dynamic loading," which employed a spinning rotor to load, transfer, and analyze blood samples by centrifugal processing. A refined, commercial version of the system was produced by ABAXIS and is marketed as portable ABAXIS MiniLab MCA. Used in a doctor's office, the equipment can perform 80 to 100 chemical blood tests on a single drop of blood and report results in five minutes. Further development is anticipated.

  10. [Quantitative analysis of landscape conditions of the desertified sandy grassland in Ordos Plateau].

    PubMed

    Chen, Yufu; Dong, Ming

    2002-01-30

    The landscape condition of the sandy grassland in southeast of Ordos Plateau was analyzed based on the data from field investigation along two intercepting 5 km transects. Summary on frequency of the patches showed that small-scale patches were prominent in this area, with 95% of total patches smaller than 50 m and average dimension of patches 15 m, while there were also a couple of large-scale mobile sandy patches. Environmental heterogeneity dependent on spatial scales was revealed by semivarogram in the sampling area. The large fractal dimensions of percent coverage of bare ground, close to 2, indicated dominant small-scale spatial variance. This result implies a relative stabilized landscape and also a desertified area. PMID:11987415

  11. Process Analyzer

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Under a NASA Small Business Innovation Research (SBIR) contract, Axiomatics Corporation developed a shunting Dielectric Sensor to determine the nutrient level and analyze plant nutrient solutions in the CELSS, NASA's space life support program. (CELSS is an experimental facility investigating closed-cycle plant growth and food processing for long duration manned missions.) The DiComp system incorporates a shunt electrode and is especially sensitive to changes in dielectric property changes in materials at measurements much lower than conventional sensors. The analyzer has exceptional capabilities for predicting composition of liquid streams or reactions. It measures concentrations and solids content up to 100 percent in applications like agricultural products, petrochemicals, food and beverages. The sensor is easily installed; maintenance is low, and it can be calibrated on line. The software automates data collection and analysis.

  12. Oxygen analyzer

    DOEpatents

    Benner, W.H.

    1984-05-08

    An oxygen analyzer which identifies and classifies microgram quantities of oxygen in ambient particulate matter and for quantitating organic oxygen in solvent extracts of ambient particulate matter. A sample is pyrolyzed in oxygen-free nitrogen gas (N/sub 2/), and the resulting oxygen quantitatively converted to carbon monoxide (CO) by contact with hot granular carbon (C). Two analysis modes are made possible: (1) rapid determination of total pyrolyzable obtained by decomposing the sample at 1135/sup 0/C, or (2) temperature-programmed oxygen thermal analysis obtained by heating the sample from room temperature to 1135/sup 0/C as a function of time. The analyzer basically comprises a pyrolysis tube containing a bed of granular carbon under N/sub 2/, ovens used to heat the carbon and/or decompose the sample, and a non-dispersive infrared CO detector coupled to a mini-computer to quantitate oxygen in the decomposition products and control oven heating.

  13. Oxygen analyzer

    DOEpatents

    Benner, William H.

    1986-01-01

    An oxygen analyzer which identifies and classifies microgram quantities of oxygen in ambient particulate matter and for quantitating organic oxygen in solvent extracts of ambient particulate matter. A sample is pyrolyzed in oxygen-free nitrogen gas (N.sub.2), and the resulting oxygen quantitatively converted to carbon monoxide (CO) by contact with hot granular carbon (C). Two analysis modes are made possible: (1) rapid determination of total pyrolyzable oxygen obtained by decomposing the sample at 1135.degree. C., or (2) temperature-programmed oxygen thermal analysis obtained by heating the sample from room temperature to 1135.degree. C. as a function of time. The analyzer basically comprises a pyrolysis tube containing a bed of granular carbon under N.sub.2, ovens used to heat the carbon and/or decompose the sample, and a non-dispersive infrared CO detector coupled to a mini-computer to quantitate oxygen in the decomposition products and control oven heating.

  14. Atmosphere Analyzer

    NASA Technical Reports Server (NTRS)

    1982-01-01

    California Measurements, Inc.'s model PC-2 Aerosol Particle Analyzer is produced in both airborne and ground-use versions. Originating from NASA technology, it is a quick and accurate method of detecting minute amounts of mass loadings on a quartz crystal -- offers utility as highly sensitive detector of fine particles suspended in air. When combined with suitable air delivery system, it provides immediate information on the size distribution and mass concentrations of aerosols. William Chiang, obtained a NASA license for multiple crystal oscillator technology, and initially developed a particle analyzer for NASA use with Langley Research Center assistance. Later his company produced the modified PC-2 for commercial applications Brunswick Corporation uses the device for atmospheric research and in studies of smoke particles in Fires. PC-2 is used by pharmaceutical and chemical companies in research on inhalation toxicology and environmental health. Also useful in testing various filters for safety masks and nuclear installations.

  15. Is Sandy Beach Macrofauna Only Physically Controlled? Role of Substrate and Competition in Isopods

    NASA Astrophysics Data System (ADS)

    Defeo, O.; Brazeiro, A.; de Alava, A.; Riestra, G.

    1997-10-01

    Exposed sandy beaches have been defined as physically stressful environments, so that benthic populations living there are thought to be regulated mainly by physical factors, biological interactions being minimal. However, recent long-term studies indicate that potential intra- and interspecific interactions should also play a role in structuring populations and communities. This paper evaluates the role of sediment characteristics and potential interactions in determining the abundance and distribution patterns of the cirolanid isopods Excirolana armataand Excirolana braziliensisin sandy beaches of Uruguay. Results from concurrent field sampling and laboratory experiments showed that: (1) at a macroscale (between beaches), E. armataoccurred only in beaches with fine sands, whereas E. braziliensiswas observed in both fine and coarse sand beaches, reaching its highest density in the latter; (2) at a mesoscale (within beaches) and in sympatry (fine sands), both cirolanids showed maximum densities at different tidal heights, with E. braziliensisrestricted to the upper beach levels; (3) both isopods showed a clear preference for fine sands, when tested in isolation or combined; (4) survivorship of E. armatawas higher when tested in the preferred sediment under co-occurrence with E. braziliensis, which in turn presented higher survivorship in coarse sand, either in isolation or combined with E. armata; and (5) individual mean length of both species was consistently higher in allopatry, and similar body lengths were observed in sympatric populations. A geographical analysis of the abundance of E. braziliensisalong Pan-American beaches showed that this isopod is most abundant in fine sands; this overall pattern supports conclusions derived from sediment preference experiments, implicating a greater niche breadth than that observed in Uruguayan beaches. It was concluded that E. armatacould be defined as a high substrate-specific species in which intraspecific interactions

  16. MULTICHANNEL ANALYZER

    DOEpatents

    Kelley, G.G.

    1959-11-10

    A multichannel pulse analyzer having several window amplifiers, each amplifier serving one group of channels, with a single fast pulse-lengthener and a single novel interrogation circuit serving all channels is described. A pulse followed too closely timewise by another pulse is disregarded by the interrogation circuit to prevent errors due to pulse pileup. The window amplifiers are connected to the pulse lengthener output, rather than the linear amplifier output, so need not have the fast response characteristic formerly required.

  17. Sources, Transport, and Storage of Sediment at Selected Sites in the Chesapeake Bay Watershed

    USGS Publications Warehouse

    Gellis, Allen C.; Hupp, Cliff R.; Pavich, Milan J.; Landwehr, Jurate M.; Banks, William S.L.; Hubbard, Bernard E.; Langland, Michael J.; Ritchie, Jerry C.; Reuter, Joanna M.

    2009-01-01

    The Chesapeake Bay Watershed covers 165,800 square kilometers and is supplied with water and sediment from five major physiographic provinces: Appalachian Plateau, Blue Ridge, Coastal Plain, Piedmont, and the Valley and Ridge. Suspended-sediment loads measured in the Chesapeake Bay Watershed showed that the Piedmont Physiographic Province has the highest rates of modern (20th Century) sediment yields, measured at U.S. Geological Survey streamflow-gaging stations, and the lowest rates of background or geologic rates of erosion (~10,000 years) measured with in situ beryllium-10. In the agricultural and urbanizing Little Conestoga Creek Watershed, a Piedmont watershed, sources of sediment using the 'sediment-fingerprinting' approach showed that streambanks were the most important source (63 percent), followed by cropland (37 percent). Cesium-137 inventories, which quantify erosion rates over a 40-year period, showed average cropland erosion of 19.39 megagrams per hectare per year in the Little Conestoga Creek Watershed. If this erosion rate is extrapolated to the 13 percent of the watershed that is in cropland, then cropland could contribute almost four times the measured suspended-sediment load transported out of the watershed (27,600 megagrams per hectare per year), indicating that much of the eroded sediment is being deposited in channel and upland storage. The Piedmont has had centuries of land-use change, from forest to agriculture, to suburban and urban areas, and in some areas, back to forest. These land-use changes mobilized a large percentage of sediment that was deposited in upland and channel storage, and behind thousands of mill dams. The effects of these land-use changes on erosion and sediment transport are still being observed today as stored sediment in streambanks is a source of sediment. Cropland is also an important source of sediment. The Coastal Plain Physiographic Province has had the lowest sediment yields in the 20th Century and with sandy

  18. Geomorphic response of the Sandy River, Oregon, to removal of Marmot Dam

    USGS Publications Warehouse

    Major, Jon J.; O'Connor, Jim E.; Podolak, Charles J.; Keith, Mackenzie K.; Grant, Gordon E.; Spicer, Kurt R.; Pittman, Smokey; Bragg, Heather M.; Wallick, J. Rose; Tanner, Dwight Q.; Rhode, Abagail; Wilcock, Peter R.

    2012-01-01

    The October 2007 breaching of a temporary cofferdam constructed during removal of the 15-meter (m)-tall Marmot Dam on the Sandy River, Oregon, triggered a rapid sequence of fluvial responses as ~730,000 cubic meters (m3) of sand and gravel filling the former reservoir became available to a high-gradient river. Using direct measurements of sediment transport, photogrammetry, airborne light detection and ranging (lidar) surveys, and, between transport events, repeat ground surveys of the reservoir reach and channel downstream, we monitored the erosion, transport, and deposition of this sediment in the hours, days, and months following breaching of the cofferdam. Rapid erosion of reservoir sediment led to exceptional suspended-sediment and bedload-sediment transport rates near the dam site, as well as to elevated transport rates at downstream measurement sites in the weeks and months after breaching. Measurements of sediment transport 0.4 kilometers (km) downstream of the dam site during and following breaching show a spike in the transport of fine suspended sediment within minutes after breaching, followed by high rates of suspended-load and bedload transport of sand. Significant transport of gravel bedload past the measurement site did not begin until 18 to 20 hours after breaching. For at least 7 months after breaching, bedload transport rates just below the dam site during high flows remained as much as 10 times above rates measured upstream of the dam site and farther downstream. The elevated sediment load was derived from eroded reservoir sediment, which began eroding when a meters-tall knickpoint migrated about 200 m upstream in the first hour after breaching. Rapid knickpoint migration triggered vertical incision and bank collapse in unconsolidated sand and gravel, leading to rapid channel widening. Over the following days and months, the knickpoint migrated upstream more slowly, simultaneously decreasing in height and becoming less distinct. Within 7 months

  19. The impact of onsite wastewater disposal systems on groundwater in areas inundated by Hurricane Sandy in New York and New Jersey.

    PubMed

    Fisher, Irene J; Phillips, Patrick J; Colella, Kaitlyn M; Fisher, Shawn C; Tagliaferri, Tristen; Foreman, William T; Furlong, Edward T

    2016-06-30

    Coastal onsite wastewater disposal systems (OWDS) were inundated by Hurricane Sandy's storm tide. This study compares the shallow groundwater quality (nutrients, pharmaceuticals, and hormones) downgradient of OWDS before and after Hurricane Sandy, where available, and establishes a baseline for wastewater influence on groundwater in coastal communities inundated by Hurricane Sandy. Nutrients and contaminants of emerging concern (CECs) were detected in shallow groundwater downgradient of OWDS in two settings along the New Jersey and New York coastlines: 1) a single, centralized OWDS in a park; and 2) multiple OWDS (cesspools) in low-density residential and mixed-use/medium density residential areas. The most frequently detected pharmaceuticals were lidocaine (40%), carbamazepine (36%), and fexofenadine, bupropion, desvenlafaxine, meprobamate, and tramadol (24-32%). Increases in the number and total concentration of pharmaceuticals after Hurricane Sandy may reflect other factors (seasonality, usage) besides inundation, and demonstrate the importance of analyzing for a wide variety of CECs in regional studies. PMID:27261279

  20. The impact of onsite wastewater disposal systems on groundwater in areas inundated by Hurricane Sandy in New York and New Jersey

    USGS Publications Warehouse

    Fisher, Irene; Phillips, Patrick; Colella, Kaitlyn; Fisher, Shawn C.; Tagliaferri, Tristen N.; Foreman, William; Furlong, Edward T.

    2016-01-01

    Coastal onsite wastewater disposal systems (OWDS) were inundated by Hurricane Sandy's storm tide. This study compares the shallow groundwater quality (nutrients, pharmaceuticals, and hormones) downgradient of OWDS before and after Hurricane Sandy, where available, and establishes a baseline for wastewater influence on groundwater in coastal communities inundated by Hurricane Sandy. Nutrients and contaminants of emerging concern (CECs) were detected in shallow groundwater downgradient of OWDS in two settings along the New Jersey and New York coastlines: 1) a single, centralized OWDS in a park; and 2) multiple OWDS (cesspools) in low-density residential and mixed-use/medium density residential areas. The most frequently detected pharmaceuticals were lidocaine (40%), carbamazepine (36%), and fexofenadine, bupropion, desvenlafaxine, meprobamate, and tramadol (24–32%). Increases in the number and total concentration of pharmaceuticals after Hurricane Sandy may reflect other factors (seasonality, usage) besides inundation, and demonstrate the importance of analyzing for a wide variety of CECs in regional studies.

  1. Metabolic analyzer

    NASA Technical Reports Server (NTRS)

    Lem, J. D.

    1977-01-01

    The metabolic analyzer was designed to support experiment M171. It operates on the so-called open circuit method to measure a subject's metabolic activity in terms of oxygen consumed, carbon dioxide produced, minute volume, respiratory exchange ratio, and tidal volume or vital capacity. The system operates in either of two modes. (1) In Mode I, inhaled respiratory volumes are actually measured by a piston spirometer. (2) In Mode II, inhaled volumes are calculated from the exhaled volume and the measured inhaled and exhaled nitrogen concentrations. This second mode was the prime mode for Skylab. Following is a brief description of the various subsystems and their operation.

  2. Gas Analyzer

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A miniature gas chromatograph, a system which separates a gaseous mixture into its components and measures the concentration of the individual gases, was designed for the Viking Lander. The technology was further developed under National Institute for Occupational Safety and Health (NIOSH) and funded by Ames Research Center/Stanford as a toxic gas leak detection device. Three researchers on the project later formed Microsensor Technology, Inc. to commercialize the product. It is a battery-powered system consisting of a sensing wand connected to a computerized analyzer. Marketed as the Michromonitor 500, it has a wide range of applications.

  3. Contamination Analyzer

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Measurement of the total organic carbon content in water is important in assessing contamination levels in high purity water for power generation, pharmaceutical production and electronics manufacture. Even trace levels of organic compounds can cause defects in manufactured products. The Sievers Model 800 Total Organic Carbon (TOC) Analyzer, based on technology developed for the Space Station, uses a strong chemical oxidizing agent and ultraviolet light to convert organic compounds in water to carbon dioxide. After ionizing the carbon dioxide, the amount of ions is determined by measuring the conductivity of the deionized water. The new technique is highly sensitive, does not require compressed gas, and maintenance is minimal.

  4. Analyzing Orientations

    NASA Astrophysics Data System (ADS)

    Ruggles, Clive L. N.

    Archaeoastronomical field survey typically involves the measurement of structural orientations (i.e., orientations along and between built structures) in relation to the visible landscape and particularly the surrounding horizon. This chapter focuses on the process of analyzing the astronomical potential of oriented structures, whether in the field or as a desktop appraisal, with the aim of establishing the archaeoastronomical "facts". It does not address questions of data selection (see instead Chap. 25, "Best Practice for Evaluating the Astronomical Significance of Archaeological Sites", 10.1007/978-1-4614-6141-8_25) or interpretation (see Chap. 24, "Nature and Analysis of Material Evidence Relevant to Archaeoastronomy", 10.1007/978-1-4614-6141-8_22). The main necessity is to determine the azimuth, horizon altitude, and declination in the direction "indicated" by any structural orientation. Normally, there are a range of possibilities, reflecting the various errors and uncertainties in estimating the intended (or, at least, the constructed) orientation, and in more formal approaches an attempt is made to assign a probability distribution extending over a spread of declinations. These probability distributions can then be cumulated in order to visualize and analyze the combined data from several orientations, so as to identify any consistent astronomical associations that can then be correlated with the declinations of particular astronomical objects or phenomena at any era in the past. The whole process raises various procedural and methodological issues and does not proceed in isolation from the consideration of corroborative data, which is essential in order to develop viable cultural interpretations.

  5. GOES-13 Sees Life and Death of Hurricane Sandy

    NASA Video Gallery

    This animation of satellite imagery shows the life of Hurricane Sandy from its development in the Caribbean Sea on Oct. 21, through its track up the U.S. East coast and landfall. The animation cont...

  6. On the Impact Angle of Hurricane Sandy's New Jersey Landfall

    NASA Technical Reports Server (NTRS)

    Hall, Timothy M.; Sobel, Adam H.

    2013-01-01

    Hurricane Sandy's track crossed the New Jersey coastline at an angle closer to perpendicular than any previous hurricane in the historic record, one of the factors contributing to recordsetting peak-water levels in parts of New Jersey and New York. To estimate the occurrence rate of Sandy-like tracks, we use a stochastic model built on historical hurricane data from the entire North Atlantic to generate a large sample of synthetic hurricanes. From this synthetic set we calculate that under long-term average climate conditions, a hurricane of Sandy's intensity or greater (category 1+) makes NJ landfall at an angle at least as close to perpendicular as Sandy's at an average annual rate of 0.0014 yr-1 (95% confidence range 0.0007 to 0.0023); i.e., a return period of 714 years (95% confidence range 435 to 1429).

  7. Optical analyzer

    DOEpatents

    Hansen, A.D.

    1987-09-28

    An optical analyzer wherein a sample of particulate matter, and particularly of organic matter, which has been collected on a quartz fiber filter is placed in a combustion tube, and light from a light source is passed through the sample. The temperature of the sample is raised at a controlled rate and in a controlled atmosphere. The magnitude of the transmission of light through the sample is detected as the temperature is raised. A data processor, differentiator and a two pen recorder provide a chart of the optical transmission versus temperature and the rate of change of optical transmission versus temperature signatures (T and D) of the sample. These signatures provide information as to physical and chemical processes and a variety of quantitative and qualitative information about the sample. Additional information is obtained by repeating the run in different atmospheres and/or different rates or heating with other samples of the same particulate material collected on other filters. 7 figs.

  8. Speech analyzer

    NASA Technical Reports Server (NTRS)

    Lokerson, D. C. (Inventor)

    1977-01-01

    A speech signal is analyzed by applying the signal to formant filters which derive first, second and third signals respectively representing the frequency of the speech waveform in the first, second and third formants. A first pulse train having approximately a pulse rate representing the average frequency of the first formant is derived; second and third pulse trains having pulse rates respectively representing zero crossings of the second and third formants are derived. The first formant pulse train is derived by establishing N signal level bands, where N is an integer at least equal to two. Adjacent ones of the signal bands have common boundaries, each of which is a predetermined percentage of the peak level of a complete cycle of the speech waveform.

  9. Using Repeat LiDAR Surveys to Determine the Geomorphic Changes Related the Removal of the Marmot Dam on the Sandy River, Oregon

    NASA Astrophysics Data System (ADS)

    Matzek, C. D.; Ely, L. L.; O'Connor, J. E.

    2012-12-01

    The removal of the Marmot Dam on the Sandy River, Oregon in October 2007 released an estimated 430,000 m3 of sand and gravel downstream. Field surveys by Major and others (Major and others, USGS Professional Paper 1792) following the dam removal documented deposition of nearly half of the eroded sediment (215,000 m3) in the first 2 km downstream of the dam within a year of breaching. However, the fate of more than 200,000 m3 of chiefly sand transported farther downstream is uncertain. In the current study, five sequential LiDAR data sets from 2006 to 2011 were used to quantify sediment storage and erosion in the 40 km from the former dam site to the confluence with the Columbia River to track the downstream movement of the sediment released from the reservoir. We hypothesized that a pulse of sediment from the dam removal would be distinguished by a successive downstream growth of sediment bars through time. The LiDAR imagery includes two data sets acquired before the dam removal and three afterward. Geomorphic Change Detection software (GCD) (gcd.joewheaton.org) was used to quantify the locations and volume of sediment erosion and deposition through the successive years of LiDAR imagery. GCD allows for error assessment of each LiDAR-derived digital elevation map (DEM) and propagates the combined errors when differencing two repeat surveys. This process allows creation of DEM of Difference (DoD) maps with associated uncertainty estimates. Preliminary results of the LiDAR analysis agree with the previous field estimates of deposition within the first 2 km from the former dam. Following the initial phase of deposition immediately downstream of the dam breach, the subsequent surveys (2008-2011) show an erosional front beginning to migrate downstream through the newly deposited sediment. Many of the sediment bars still remained in 2011, but were reduced in size. After calibrating the model in the 2-km reach below the dam, we analyzed the additional 38 km of channel

  10. Optical analyzer

    DOEpatents

    Hansen, Anthony D.

    1989-02-07

    An optical analyzer (10) wherein a sample (19) of particulate matter, and particularly of organic matter, which has been collected on a quartz fiber filter (20) is placed in a combustion tube (11), and light from a light source (14) is passed through the sample (19). The temperature of the sample (19) is raised at a controlled rate and in a controlled atmosphere. The magnitude of the transmission of light through the sample (19) is detected (18) as the temperature is raised. A data processor (23), differentiator (28) and a two pen recorder (24) provide a chart of the optical transmission versus temperature and the rate of change of optical transmission versus temperature signatures (T and D) of the sample (19). These signatures provide information as to physical and chemical processes and a variety of quantitative and qualitative information about the sample (19). Additional information is obtained by repeating the run in different atmospheres and/or different rates of heating with other samples of the same particulate material collected on other filters.

  11. Optical analyzer

    DOEpatents

    Hansen, Anthony D.

    1989-01-01

    An optical analyzer (10) wherein a sample (19) of particulate matter, and particularly of organic matter, which has been collected on a quartz fiber filter (20) is placed in a combustion tube (11), and light from a light source (14) is passed through the sample (19). The temperature of the sample (19) is raised at a controlled rate and in a controlled atmosphere. The magnitude of the transmission of light through the sample (19) is detected (18) as the temperature is raised. A data processor (23), differentiator (28) and a two pen recorder (24) provide a chart of the optical transmission versus temperature and the rate of change of optical transmission versus temperature signatures (T and D) of the sample (19). These signatures provide information as to physical and chemical processes and a variety of quantitative and qualitative information about the sample (19). Additional information is obtained by repeating the run in different atmospheres and/or different rates of heating with other samples of the same particulate material collected on other filters.

  12. Attitudinal Determinants of Local Public Health Workers' Participation in Hurricane Sandy Recovery Activities.

    PubMed

    Errett, Nicole A; Egan, Shannon; Garrity, Stephanie; Rutkow, Lainie; Walsh, Lauren; Thompson, Carol B; Strauss-Riggs, Kandra; Altman, Brian; Schor, Kenneth; Barnett, Daniel J

    2015-01-01

    Local health departments play a critical role in short-, intermediate-, and long-term recovery activities after a public health emergency. However, research has not explored attitudinal determinants of health department workers' participation in the recovery phase following a disaster. Accordingly, this qualitative investigation aims to understand perceived facilitators and barriers to performing recovery-related activities following Hurricane Sandy among local health department workers. In January 2014, 2 focus groups were conducted in geographically representative clusters of local health departments affected by Hurricane Sandy (1 cluster in Maryland and 1 cluster in New Jersey). Focus groups were recorded, transcribed verbatim, and analyzed to qualitatively assess attitudes toward Hurricane Sandy recovery activities. This analysis identified 5 major thematic categories as facilitators and barriers to participation in recovery activities: training, safety, family preparedness, policies and planning, and efficacy. Systems that support engagement of health department personnel in recovery activities may endeavor to develop and communicate intra- and interjurisdictional policies that minimize barriers in these areas. Development and implementation of evidence-informed curricular interventions that explain recovery roles may also increase local health department worker motivation to participate in recovery activities. PMID:26173013

  13. Bubble growth and rise in soft sediments

    NASA Astrophysics Data System (ADS)

    Boudreau, Bernard P.; Algar, Chris; Johnson, Bruce D.; Croudace, Ian; Reed, Allen; Furukawa, Yoko; Dorgan, Kelley M.; Jumars, Peter A.; Grader, Abraham S.; Gardiner, Bruce S.

    2005-06-01

    The mechanics of uncemented soft sediments during bubble growth are not widely understood and no rheological model has found wide acceptance. We offer definitive evidence on the mode of bubble formation in the form of X-ray computed tomographic images and comparison with theory. Natural and injected bubbles in muddy cohesive sediments are shown to be highly eccentric oblate spheroids (disks) that grow either by fracturing the sediment or by reopening preexisting fractures. In contrast, bubbles in soft sandy sediment tend to be spherical, suggesting that sand acts fluidly or plastically in response to growth stresses. We also present bubble-rise results from gelatin, a mechanically similar but transparent medium, that suggest that initial rise is also accomplished by fracture. Given that muddy sediments are elastic and yield by fracture, it becomes much easier to explain physically related phenomena such as seafloor pockmark formation, animal burrowing, and gas buildup during methane hydrate melting.

  14. Food web structure of sandy beaches: Temporal and spatial variation using stable isotope analysis

    NASA Astrophysics Data System (ADS)

    Bergamino, Leandro; Lercari, Diego; Defeo, Omar

    2011-03-01

    The food web structure of two sandy beach ecosystems with contrasting morphodynamics (dissipative vs. reflective) was examined using stable carbon (δ 13C) and nitrogen (δ 15N) isotope analysis. Organic matter sources (POM: particulate organic matter; SOM: sediment organic matter) and consumers (zooplankton, benthic invertebrates and fishes) were sampled seasonally in both sandy beaches. Food webs significantly differed between beaches: even though both webs were mainly supported by POM, depleted δ 13C and δ 15N values for food sources and consumers were found in the dissipative system (following the reverse pattern in δ 13C values for consumers) for all the four seasons. Primary consumers (zooplankton and benthic invertebrates) use different organic matter sources on each beach and these differences are propagated up in the food web. The higher productivity found in the dissipative beach provided a significant amount of food for primary consumers, notably suspension feeders. Thus, the dissipative beach supported a more complex food web with more trophic links and a higher number of prey and top predators than the reflective beach. Morphodynamic factors could explain the contrasting differences in food web structure. The high degree of retention (nutrients and phytoplankton) recorded for the surf zone of the dissipative beach would result in the renewed accumulation of POM that sustains a more diverse and richer fauna than the reflective beach. Further studies directed to assess connections between the macroscopic food web, the surf-zone microbial loop and the interstitial compartment will provide a deeper understanding on the functioning of sandy beach ecosystems.

  15. Statistical Analysis of Small-Scale Bedforms Formed by Hurricane Sandy Offshore Fire Island, New York

    NASA Astrophysics Data System (ADS)

    Arora, K.; Goff, J. A.; Wood, L. J.; Flood, R. D.

    2014-12-01

    Multibeam bathymetry surveys acquired two months after hurricane Sandy offshore of Fire Island, NY, revealed broad areas of small-scale (<15 m) bedforms on top of large-scale (200-3000 m) sand ridges and sorted bedforms. The small-scale bedforms were absent prior to the hurricane, as evidenced by previous surveys in 2003 and 2011. Here we statistically analyze these bedforms in conjunction with seabed sedimentary properties and storm history to understand the correlation of sedimentary deposition with the storm history. The Fire Island shoreface/inner shelf has been the site of ongoing studies by the USGS. The western half is dominated by 1-3 km-wide sand ridges, with abundant fine-medium sand. The eastern half, on the other hand, is largely starved of modern sand, and the bedform morphology is dominated by 0.2-1.0 km-wide sorted bedforms. We utilize two post-storm surveys, one along the western half of the island and the other to the east, providing an opportunity to compare these different nearshore settings. A Gaussian covariance model is used, with four parameters: rms height, orientation and characteristics length and width. An iterative, least-squares inversion is used to estimate these parameters and their uncertainties from selected sample areas. Bedforms with aspect ratio (length/width) > 1.5 are categorized as two-dimensional, and have rms heights ~3-7 cm and widths 4-6 m. Bedforms with aspect ratio < 1.5 are categorized as three-dimensional, and have smaller rms heights (~1.5-4 cm) and larger widths (~6-13 m). Parameters are correlatable with grain size and large-scale bedform topography. Three-dimensional bedforms tend to form in finer sands and have been interpreted as hummocky bedforms formed by long-period surface gravity waves generated during the storm. The two-dimensional bedforms are interpreted as large ripples that show consistent lineation oblique to the orientation of larger sand ridges. For this study we will compare bedform lineations to

  16. Global patterns in sandy beach macrofauna: Species richness, abundance, biomass and body size

    NASA Astrophysics Data System (ADS)

    Defeo, Omar; McLachlan, Anton

    2013-10-01

    Global patterns in species richness in sandy beach ecosystems have been poorly understood until comparatively recently, because of the difficulty of compiling high-resolution databases at continental scales. We analyze information from more than 200 sandy beaches around the world, which harbor hundreds of macrofauna species, and explore latitudinal trends in species richness, abundance and biomass. Species richness increases from temperate to tropical sites. Abundance follows contrasting trends depending on the slope of the beach: in gentle slope beaches, it is higher at temperate sites, whereas in steep-slope beaches it is higher at the tropics. Biomass follows identical negative trends for both climatic regions at the whole range of beach slopes, suggesting decreasing rates in carrying capacity of the environment towards reflective beaches. Various morphodynamic variables determine global trends in beach macrofauna. Species richness, abundance and biomass are higher at dissipative than at reflective beaches, whereas a body size follows the reverse pattern. A generalized linear model showed that large tidal range (which determines the vertical dimension of the intertidal habitat), small size of sand particles and flat beach slope (a product of the interaction among wave energy, tidal range and grain size) are correlated with high species richness, suggesting that these parameters represent the most parsimonious variables for modelling patterns in sandy beach macrofauna. Large-scale patterns indicate a scaling of abundance to a body size, suggesting that dissipative beaches harbor communities with highest abundance and species with the smallest body sizes. Additional information for tropical and northern hemisphere sandy beaches (underrepresented in our compilation) is required to decipher more conclusive trends, particularly in abundance, biomass and body size. Further research should integrate meaningful oceanographic variables, such as temperature and primary

  17. Shoreline change patterns in sandy coasts. A case study in SW Spain

    NASA Astrophysics Data System (ADS)

    Del Río, Laura; Gracia, F. Javier; Benavente, Javier

    2013-08-01

    Coastal changes on sandy shorelines are continuous and occur at diverse spatial and temporal scales. Gaining knowledge on beach change processes increases our capability to manage risks, especially shoreline erosion, affecting the increasing population living in coastal areas. Processes and factors involved in medium- and short-term beach changes depend on the morphological and dynamic characteristics of the coast. In this work, the decadal behaviour of 58 sandy beaches along the 150 km long South-Atlantic coast of Spain, between the Guadalquivir river mouth and the Strait of Gibraltar, is analysed in order to investigate the relationships between shoreline change patterns and the diverse morphological and dynamic factors controlling beach evolution in the area. For this purpose, georectified aerial photographs spanning the period 1956-2008 were compared in a GIS environment to calculate rates of shoreline change. Short-term evolution of beach profiles was also analysed in selected areas of interest. Results show that the study area exhibits a great variety of shoreline evolution trends, with erosion prevailing in the northern and central sectors and stability or even accretion in the southern sector. In general, sediment availability is the main factor determining coastal erodibility in the area, largely conditioned by the reduction in fluvial sediment supply caused by river basin regulation. Nearshore bathymetry also has a great significance, as it controls wave refraction-diffraction patterns and wave energy concentration on certain zones. Human interventions on the coast also represent a major influence on beach erodibility in the study area. Severe detrimental effects are caused at certain points by shore-normal engineering structures blocking longshore drift. Additionally extensive urban development in backbeach environments has a significant influence on the sediment budget at certain areas. On the basis of these results, a morphological and evolutionary

  18. ABSORPTION ANALYZER

    DOEpatents

    Brooksbank, W.A. Jr.; Leddicotte, G.W.; Strain, J.E.; Hendon, H.H. Jr.

    1961-11-14

    A means was developed for continuously computing and indicating the isotopic assay of a process solution and for automatically controlling the process output of isotope separation equipment to provide a continuous output of the desired isotopic ratio. A counter tube is surrounded with a sample to be analyzed so that the tube is exactly in the center of the sample. A source of fast neutrons is provided and is spaced from the sample. The neutrons from the source are thermalized by causing them to pass through a neutron moderator, and the neutrons are allowed to diffuse radially through the sample to actuate the counter. A reference counter in a known sample of pure solvent is also actuated by the thermal neutrons from the neutron source. The number of neutrons which actuate the detectors is a function of a concentration of the elements in solution and their neutron absorption cross sections. The pulses produced by the detectors responsive to each neu tron passing therethrough are amplified and counted. The respective times required to accumulate a selected number of counts are measured by associated timing devices. The concentration of a particular element in solution may be determined by utilizing the following relation: T2/Ti = BCR, where B is a constant proportional to the absorption cross sections, T2 is the time of count collection for the unknown solution, Ti is the time of count collection for the pure solvent, R is the isotopic ratlo, and C is the molar concentration of the element to be determined. Knowing the slope constant B for any element and when the chemical concentration is known, the isotopic concentration may be readily determined, and conversely when the isotopic ratio is known, the chemical concentrations may be determined. (AEC)

  19. Vertical variation of potential mobility of heavy metal in sediment to groundwater of the Kanto plain, Japan

    NASA Astrophysics Data System (ADS)

    Hossain, S.; Hachinohe, S.; Ishiyama, T.; Hamamoto, H.; Oguchi, C. T.

    2014-12-01

    Heavy metals release from sediment may occur due to sediment water interaction under different changing environmental conditions. This has substantial influence on groundwater quality. However, identification of potentially mobile fractions of metals like Cu, Cr, Ni, Pb, Zn, Fe, Mn and Ti requires for the sustainable land and groundwater development and pollution management. 44 sediment and pore water samples at 1 m interval were analyzed from a vertical profile beneath the Naka river at the bottom of Central Kanto plain, Japan. Sequential extraction method was applied to determine potentially mobile forms of metals such as water soluble, ion exchangeable, acid soluble and Fe-Mn oxide bound. Metals were determined using X-Ray Fluorescence, Inductively coupled plasma atomic emission and mass spectrometer. Analyses show that potential mobility is high in river bed, volcanic ash mix, marine and transitional clayey silt. Metal mobility was higher in lower gravelly aquifer than upper sandy aquifer. Potential mobility and bioavailability of Zn, Cu, Ni, Pb and Mn are very high in river bed sediment which may pose threat to river bottom aquatic system. Zn, Cu and Ni concentration in pore water is high in river bed and peat bearing sediment. In pore water of marine and transitional sediment ion concentration such as Ca2+ and SO42- is very high indicating high mobility of Calcium and Sulfur from sediment as no significant variation observed in total content. In vertical profile, potential mobility tendency of metal in sediment trends to be Zn > Cu > Ni > Cr > Pb > Mn > Fe > Ti. Current study indicates low potential mobility and pollution risk to groundwater due to overall low metal concentration in pore water and high portion of metals attached with sediment as Fe-Mn oxide bound. More over under strong reducing condition considerable amount of metals will release and pollute groundwater.

  20. Evolving fluvial response of the Sandy River, Oregon, following removal of Marmot Dam

    USGS Publications Warehouse

    Major, Jon J.; O'Connor, Jim; Podolak, Charles J.; Keith, Mackenzie K.; Spicer, Kurt R.; Wallick, J. Rose; Bragg, Heather M.; Pittman, Smokey; Wilcock, Peter R.; Rhode, Abagail; Grant, Gordon E.

    2010-01-01

    The October 2007 removal of Marmot Dam on the Sandy River, Oregon, triggered a rapid sequence of fluvial responses as ~730,000 m3 of sand and gravel that filled the former reservoir were suddenly exposed to an energetic river. Using direct measurements of sediment transport, photogrammetry, and repeat surveys between transport events, we monitored the erosion, transport, and redeposition of this sediment in the hours, days, and months following breaching. Measurements of suspended load and bedload documented an initial spike in the flux of fine suspended sediment in the minutes after breaching followed by high rates of suspendedand bedload transport of sand. Significant gravel transport did not begin at a measurement site 0.4 km downstream of the dam until 18–20 hours after breaching, when bedload transport achieved rates of about 60 kg/s—rates that greatly exceeded concurrent measurements of less than 10 kg/s at sites upstream and farther downstream of the dam. Bedload transport rates just below the dam site remained 10–100 times above upstream and downstream rates through subsequent high flow events during the winter and spring of 2007 and 2008. Much of the elevated sediment load was derived from eroded reservoir sediment, which initially began eroding when a multi-meter-tall knickpoint migrated upstream 200 meters in the first hour. Rapid knickpoint migration triggered bank collapse in the unconsolidated fill, which swiftly widened the channel. Over the following days and months, the knickpoint migrated slowly upchannel, simultaneously lowering and becoming less distinct. By May 2008, a riffle-like feature approximately 1 m high, a few tens of meters long, and 2 km upstream from the breached dam persisted. Knickpoint and lateral erosion evacuated ~100,000 cubic meters of sediment from the reservoir in the first 60 hours, and by the end of high flows in May 2008 about 350,000 cubic meters (45 percent of the initial reservoir volume) had been evacuated

  1. Meiofauna distribution along a gradient of sandy beaches in northern Spain

    NASA Astrophysics Data System (ADS)

    Rodríguez, J. Germán; Lastra, Mariano; López, Jesús

    2003-10-01

    Ten sandy beaches located in northern Spain were studied during the summer of 1999 to analyse the patterns in number of major taxa, abundance and biomass of meiofauna along a gradient of morphodynamic beach types and exposure rate. Sediment samples were collected with metallic cylinders (23 cm 2 cross-sectional area, 120 cm long) at 10 equally spaced shore levels along six replicated transects extended from the drift line down to the low tide level. Wave exposure rate and Dean's parameter were estimated at each sampled beach. The meiofauna was primarily represented by Nematoda and Harpacticoidea. Meiofaunal abundances ranged between 64×10 6 and 296×10 6 ind. m-1, whereas biomass (ash free dry weight) per linear meter of beach ranged between 30 and 166 g m -1. The results showed two significant trends: (1) the meiofaunal biomass increases exponentially with exposure rate from exposed to very exposed beaches; and (2) the number of major taxa increases exponentially with exposure rate and linearly with average grain size. These trends are opposite to the general patterns of the sandy beach macroinfauna, which is generally negatively affected by increases in wave exposure and grain size. This suggests that macro- and meiofauna are affected in different ways by the physical processes associated with wave action.

  2. Removal of Fast Flowing Nitrogen from Marshes Restored in Sandy Soils

    PubMed Central

    Sparks, Eric L.; Cebrian, Just; Smith, Sara M.

    2014-01-01

    Groundwater flow rates and nitrate removal capacity from an introduced solution were examined for five marsh restoration designs and unvegetated plots shortly after planting and 1 year post-planting. The restoration site was a sandy beach with a wave-dampening fence 10 m offshore. Simulated groundwater flow into the marsh was introduced at a rate to mimic intense rainfall events. Restoration designs varied in initial planting density and corresponded to 25%, 50%, 75% and 100% of the plot area planted. In general, groundwater flow was slower with increasing planting density and decreased from year 0 to year 1 across all treatments. Nevertheless, removal of nitrate from the introduced solution was similar and low for all restoration designs (3–7%) and similar to the unvegetated plots. We suggest that the low NO3− removal was due to sandy sediments allowing rapid flow of groundwater through the marsh rhizosphere, thereby decreasing the contact time of the NO3− with the marsh biota. Our findings demonstrate that knowledge of the groundwater flow regime for restoration projects is essential when nutrient filtration is a target goal of the project. PMID:25353607

  3. Timing of turbidite sedimentation on the Mississippi Fan

    SciTech Connect

    Kolla, V. ); Perlmutter, M.A. )

    1993-07-01

    Sandy turbidite sedimentation on the Mississippi Fan, initiated during the falling and maximum relative lowstand stages of sea level during the last glacio-eustatic cycle, was significant well into the mid to late sea level during the last glacio-eustatic cycle, was significant well into the mid to late sea level rise until the Holocene, 12,000-11,000 yr B.P. or slightly thereafter. Several factors suggest this late continuation of sandy turbidite sedimentation: (1) landward extension of the Mississippi Canyon into the mid-shelf water depths as sea level rose, (2) a major increase in glacial meltwater discharge and sediment loads (pebble to clay size) delivered directly to the head of the canyon by the Mississippi River during the rising sea level, (3) probable persistent interception of longshore drift by the canyon as it eroded landward, (4) steep gradients at the head of the canyon that favored slumping of depocenters and formation of turbidity currents, and (5) absence of expected coarse-grained lithologies and deltaic stratal patterns within the canyon, indicating sediment bypass through the canyon into deep water. The late sand-prone turbidite sedimentation inferred for the Mississippi Fan is compatible with the occurrence of sandy turbidites in the middle Amazon Fan subsequent to 13,285 [+-] 650 yr B.P. and significant deposition of turbidites and clastics until the Holocene elsewhere in the deep ocean. Sand-prone turbidite sedimentation into the middle/late rise of sea level is in contrast to the common perception of sequence-stratigraphic models. This perception assumes that turbidite and fan sedimentation occurs mainly during falling. Maximum lowstand, and early rise of sea level. Late continuation of significant sandy turbidite sedimentation will impact concepts of subsurface stratigraphic calibration, interferences of depositional systems, and reservoir predictions. 56 refs., 7 figs., 1 tab.

  4. Wrack patches and their influence on upper-shore macrofaunal abundance in an Atlantic Canada sandy beach system

    NASA Astrophysics Data System (ADS)

    MacMillan, Mitchell R.; Quijón, Pedro A.

    2012-08-01

    Patches of stranded macrophytes (wrack) are a distinctive feature of sandy beaches worldwide and a potential food subsidy for their resident communities. Despite their relevance, the spatial variation of wrack and its potential influence on upper shore beach organisms remain poorly understood. Wrack and macrofauna were surveyed on seven sandy beaches associated with dunes, till bluffs and sandstone cliffs along the north shore of Prince Edward Island, Atlantic Canada. Wrack patch density, cover, and water content were measured, and their associated macrofauna was compared to the communities inhabiting nearby bare sediments. The survey found among-site spatial differences in wrack characteristics and identified rockweeds (Fucus serratus) and eelgrass (Zostera marina) as the main macrophyte species in the area. Macrofaunal abundances were higher in wrack than in bare sediments but this varied among locations. A field manipulation was then conducted at two sandy beaches to measure macrofauna colonization on patches of fresh and aged rockweed and eelgrass. Regardless of macrophyte's age, macrofaunal organisms preferentially colonized sediments associated with rockweeds. In addition, calculations across treatments detected positive relationships between macrofaunal abundance and wet mass, dry mass and water content of the wrack patches, regardless of macrophyte species or state. Macrophyte preferences were further explored by comparing the nutritional value of the plant tissues and assessing macrofauna feeding rates under laboratory conditions. Rockweed tissues had consistently higher protein, lipid and carbohydrate contents than eelgrass and were affected by higher invertebrate consumption rates. Overall, these results suggest that spatial variation and wrack features and species composition play key roles on the structure of the supralittoral macrofauna.

  5. Environmental analysis of the sediments in the beaches of the Gulf of Palermo (Italy)

    NASA Astrophysics Data System (ADS)

    Liguori, Vincenzo; Manno, Giorgio

    2016-04-01

    The gulf of Palermo is long about 30 km and the coast is closed between two headlands, Monte Gallo Cape (western side) and Zafferano Cape (east side). The continental shelf is linked with the abyssal plan by an high slope and the depth is included between 50 m and 1500 m. The shape of the Palermo gulf is the answer of both the natural forces and human activity. Nevertheless the coastal morphologies reproduce the geological setting of this area. The coast is divided in two morphotypes, low and rocky coast and beaches. Respectively composed by compact limestone and calcareous incoherent sediment with common sandy granulometry. The beaches, compressively long 11,46 km, are different in lengths, amplitude and lithological types (30% sandy and 70 % sandy-pebbly). In order to study the coastal evolution it is important to define all the coastal dynamics. The coastal evolution is actually the result of complex and intertwined action of both natural and/or anthropic processes. Nowday in the gulf of Palermo these processes exist and in some case they already triggered erosive phenomena. The westernmost beaches is the famous Mondello beach, it is made of pale sand and with sloping very low. This section of coast as other similar beaches (Arenella, Romagnolo and Acqua dei Corsari) has gone through remarkable dynamic phenomena. More precisely between 1976 and 1992 the beach (known as Arenella beach), beyond the Palermo harbor, advanced its shoreline position. Going further west along the coast one can find a landfill, partially collapsed and eroded by the impact of sea storms, that contributes to the coastal advancement from West towards East. At Romagnolo coast zone the beach has advanced because of the debris coming from local landfills, instead the Acqua dei Corsari beach (pebbles and sand) has been going through various fluctuations with a general trend towards advancement due to the longitudinal sediment transport. The study analyze the nature of sediments that made the

  6. EAARL Coastal Topography - Sandy Hook 2007

    USGS Publications Warehouse

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Stevens, Sara; Yates, Xan; Bonisteel, Jamie M.

    2008-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Northeast Coastal and Barrier Network, Kingston, RI; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of Gateway National Recreation Area's Sandy Hook Unit in New Jersey, acquired on May 16, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL) was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then

  7. Sandy River Delta Habitat Restoration Project, Annual Report 2001.

    SciTech Connect

    Kelly, Virginia; Dobson, Robin L.

    2002-11-01

    The Sandy River Delta is located at the confluence of the Sandy and Columbia Rivers, just east of Troutdale, Oregon. It comprises about 1,400 land acres north of Interstate 84, managed by the USDA Forest Service, and associated river banks managed by the Oregon Division of State Lands. Three islands, Gary, Flag and Catham, managed by Metro Greenspaces and the State of Oregon lie to the east, the Columbia River lies to the north and east, and the urbanized Portland metropolitan area lies to the west across the Sandy River. Sandy River Delta was historically a wooded, riparian wetland with components of ponds, sloughs, bottomland woodland, oak woodland, prairie, and low and high elevation floodplain. It has been greatly altered by past agricultural practices and the Columbia River hydropower system. Restoration of historic landscape components is a primary goal for this land. The Forest Service is currently focusing on restoration of riparian forest and wetlands. Restoration of open upland areas (meadow/prairie) would follow substantial completion of the riparian and wetland restoration. The Sandy River Delta is a former pasture infested with reed canary grass, blackberry and thistle. The limited over story is native riparian species such as cottonwood and ash. The shrub and herbaceous layers are almost entirely non-native, invasive species. Native species have a difficult time naturally regenerating in the thick, competing reed canary grass, Himalayan blackberry and thistle. A system of drainage ditches installed by past owners drains water from historic wetlands. The original channel of the Sandy River was diked in the 1930's, and the river diverted into the ''Little Sandy River''. The original Sandy River channel has subsequently filled in and largely become a slough. The FS acquired approximately 1,400 acres Sandy River Delta (SRD) in 1991 from Reynolds Aluminum (via the Trust for Public Lands). The Delta had been grazed for many years but shortly after FS

  8. Nematode community structure and diversity pattern in sandy beaches of Qingdao, China

    NASA Astrophysics Data System (ADS)

    Hua, Er; Mu, Fanghong; Zhang, Zhinan; Yang, Shichao; Zhang, Ting; Li, Jia

    2016-02-01

    We investigated the diversity and structure of free-living marine nematode communities at three sandy beaches representing typical intertidal environments of a temperate zone in Qingdao, Shandong Province, China. Average nematode abundance ranged from 1006 to 2170 ind. 10 cm-2, and a total of 34 nematode genera were recorded, of which only 8 were common in all the studied beaches. Pielou's evenness and Shannon-Wiener diversity index were the lowest at the second beach where nematode abundance was the highest. The highest species diversity index coincided with the lowest nematode abundance at Shilaoren beach. Sediment median grain size, sorting coefficient, and chlorophyll-a content were essential for differentiation in nematode abundance and species diversity, whereas taxonomic diversity of nematode was homogeneous across the three beaches. In 0-20 cm sediment profile, nematode abundance declined abruptly with depth, whereas nematode diversity changed gently with obvious difference in 16-20 cm layer. Sediment granulometry and chlorophyll- a content were the two foremost factors which influenced the vertical distribution pattern of nematode generic diversity. Non-selective deposit feeders constituted the most dominant trophic group, followed by epistratum feeders. Bathylaimus (family: Tripyloididae) dominated at the second and Yangkou beach, while Theristus (family: Xyalidae) prevailed at Shilaoren beach. Omnivores and predators became important at Shilaoren beach because of the high proportion of Enoplolaimus. Even though, nematode community of the studied beaches did not differ significantly from each other.

  9. The importance of biological interactions for the vertical distribution of nematodes in a temperate ultra-dissipative sandy beach

    NASA Astrophysics Data System (ADS)

    Maria, Tatiana F.; Vanaverbeke, Jan; Esteves, André M.; De Troch, Marleen; Vanreusel, Ann

    2012-01-01

    This study of the vertical distribution of nematode communities in an ultra-dissipative sandy beach on the North Sea coast at De Panne, Belgium showed species-specific vertical migrations occurred over a tidal cycle. During the period of submersion, smaller deposit feeders were dominant at the subsurface, whereas large nematodes (originally classified as predators) were concentrated at the surface. The interstitial water content showed a weak correlation to the observed patterns and biological interactions among nematodes, such as predation and competition, which were measured through stable isotopes, also explained the observed segregation. The predator Enoplolaimus litoralis and its potential prey species did not co-exist in the same part of the sediment, suggesting avoidance of predation by prey species. In addition, the different prey species inhabited different subsurface layers, which can be explained by avoidance of competition for food. Stable isotope signatures further showed that the two major biological components of sandy beaches (macrofauna and meiofauna, including some species assumed to be predators) partly depend on microphytobenthos, demonstrating the importance of in situ primary producers in the diet of the fauna from ultra-dissipative sandy beaches. However, meiofauna and macrofauna do not seem to compete for these food sources. The combined examination of environmental and biological factors revealed the additional importance of the latter in controlling the vertical distribution of nematodes in environments that were previously assumed to be mainly physically controlled.

  10. Autonomous bed-sediment imaging-systems for revealing temporal variability of grain size

    USGS Publications Warehouse

    Buscombe, Daniel; Rubin, David M.; Lacy, Jessica R.; Storlazzi, Curt D.; Hatcher, Gerald; Chezar, Henry; Wyland, Robert; Sherwood, Christopher R.

    2014-01-01

    We describe a remotely operated video microscope system, designed to provide high-resolution images of seabed sediments. Two versions were developed, which differ in how they raise the camera from the seabed. The first used hydraulics and the second used the energy associated with wave orbital motion. Images were analyzed using automated frequency-domain methods, which following a rigorous partially supervised quality control procedure, yielded estimates to within 20% of the true size as determined by on-screen manual measurements of grains. Long-term grain-size variability at a sandy inner shelf site offshore of Santa Cruz, California, USA, was investigated using the hydraulic system. Eighteen months of high frequency (min to h), high-resolution (μm) images were collected, and grain size distributions compiled. The data constitutes the longest known high-frequency record of seabed-grain size at this sample frequency, at any location. Short-term grain-size variability of sand in an energetic surf zone at Praa Sands, Cornwall, UK was investigated using the ‘wave-powered’ system. The data are the first high-frequency record of grain size at a single location of a highly mobile and evolving bed in a natural surf zone. Using this technology, it is now possible to measure bed-sediment-grain size at a time-scale comparable with flow conditions. Results suggest models of sediment transport at sandy, wave-dominated, nearshore locations should allow for substantial changes in grain-size distribution over time-scales as short as a few hours.

  11. Tsunami Sediment Transport and Deposition in a Sediment Limited Environment on American Samoa

    NASA Astrophysics Data System (ADS)

    Apotsos, A. A.; Gelfenbaum, G. R.; Jaffe, B. E.; Watt, S.; Peck, B.; Buckley, M. L.; Richmond, B. M.; Stevens, A. W.

    2009-12-01

    On 29 September 2009 a large tsunami struck the US territory of American Samoa, killing 34 people. However, had it not been for the island’s tsunami preparation, the death toll would have been much higher. An integral part of preparing for a tsunami is knowing how often large tsunamis occur, knowledge that can be improved by using paleo-tsunami sediment deposits to lengthen the historical tsunami record. Doing so requires a detailed understanding of the processes that control sediment transport during tsunamis and thus the patterns of deposition, which may vary substantially in sediment limited and sediment rich environments. As American Samoa is relatively young and composed of volcanic islands surrounded by coral reefs, sandy beaches occur primarily as pocket beaches between volcanic rock headlands. The extent and depth of littoral sediment available for transport is therefore limited. This is in contrast to previous studies which have focused primarily on coastal environments with extensive sand supply. Here, field observations and a numerical model are used to investigate tsunami-induced sediment transport in two sediment limited embayments (Massacre and Fagafue Bays) on the north side of the island of Tutuila in American Samoa. Detailed measurements of bathymetry, topography, tsunami flow depth and direction, sediment deposition, reef and vegetative roughness, and the extent of sediment available for transport were collected approximately two weeks after the tsunami. Both embayments contain sandy sediments that extend all the way (Massacre Bay) and part of the way (Fagafue Bay) along the beach at the head of the embayment. The observed onshore sediment deposit created by the tsunami was limited and patchy in both embayments even though a number of large coral boulders were transported onshore at both locations. The extent to which the limited supply of sediment plays in producing the patterns of deposition observed in these two bays is examined using a three

  12. Effects of sediment physical properties on the phosphorus release in aquatic environment

    NASA Astrophysics Data System (ADS)

    Zhu, HongWei; Wang, DaoZeng; Cheng, PengDa; Fan, JingYu; Zhong, BaoChang

    2015-02-01

    Particle size, porosity, and the initial phosphorus concentration in sediments are the main factors affecting phosphorus release flux through the sediment-water interface. Sediments can be physically divided to muddy and sandy matters, and the adsorption-desorption capacity of sediment with phosphorus depends on particle size. According to phosphorus adsorption-desorption experiments, phosphorus sorption capacity of the sediment decreases with the increase of particle dimension. But among the size-similar particles, sediment with a bigger particle size has the larger initial phosphorus release rate. In terms of muddy and sandy sediments, there are inversely proportional relationships between the release rate and the flux. Due to the contact of surface sediment and the overlying water, the release flux from the sediment is either from direct desorption of surface sediment layer or from the diffusion of pore water in the sediment layer, which is mainly determined by sediment particle size and porosity. Generally, static phosphorus release process may include two stages: the first is the initial release. As for coarse particles, phosphorus is desorbed from surface sediment. And for fine particles, phosphorus concentration in water often decreases, mainly from pore water by the molecular diffusion. During the second stage, pore water flows faster in coarse sediment, and phosphorus is easy to desorb from the surface of the particles as diffusion dominates. For the smaller liquid-solid ratio of fine particles and the larger amount of phosphorus adsorption, the release flux from pore water due to diffusion is very small with longer sorption duration.

  13. Morphodynamics and Sedimentology of a Falling Stage Sandy Fjord Delta, Goose River, Labrador

    NASA Astrophysics Data System (ADS)

    Slingerland, R.; Edmonds, D. A.; Parsons, D. R.; Best, J. L.; Royce, J.; Burpee, A.; Cederberg, J.; Caldwell, R.; Nijhuis, A.; McGuffin, A.

    2012-12-01

    Sediment size and degree of cohesion are thought to exert a strong control on the morphodynamic processes, planform shape and clinoform stratigraphy of deltas. To test model predictions concerning these two parameters, we present a morphometric and stratigraphic analysis of a sandy delta formed where the Goose River flows into Goose Bay at the western end of Lake Melville, Labrador. Goose River delta sediments consist of arkosic, heavy-mineral-rich sand (D50 = 225 to 600 microns) with very little silt and clay, placing this delta at the coarser-grained, non-cohesive end of the spectrum. The delta started to form approx. 7000 years ago as the Laurentide ice sheet retreated and post-glacial rebound created a relative base level fall of approximately 4 mm/yr. The current tidal range in Goose Bay averages 0.5 m, and the average wave height is negligible. Results from our 2012 field season show that the delta planform consists of two moribund lobes at elevations of ~ 5 m and ~ 2 m and a presently active delta at sea level. Aerial photography from 1951 to 2012 show there has been surprisingly little progradation despite active channel change at the six-month timescale and an assumed base level fall of 244 mm during that period. A topographic section along a dipline consists of three treads and two clinoform risers. The bottomset tread is a virtually featureless fjord bottom at ~35 m from which a first clinoform rises to a second tread at ~-15 m. The second tread is a sandy platform onto which an upper clinoform downlaps. This upper sandy clinoform ranges in dip from 9 to 17 dg. and passes into the topset at an elevation of ~ -1 m. The topset consists of braid-like trapezoidal unit bars that in GPR show little evidence of wave, alongshore current, or ice reworking, even though they are submerged at higher high tides. The planform, bar geometries and facies, and clinoform dips and dip-directions are remarkably consistent with model predictions from Delft3d.

  14. Legal Considerations for Health Care Practitioners After Superstorm Sandy.

    PubMed

    Hershey, Tina Batra; Van Nostrand, Elizabeth; Sood, Rishi K; Potter, Margaret

    2016-06-01

    During disaster response and recovery, legal issues often arise related to the provision of health care services to affected residents. Superstorm Sandy led to the evacuation of many hospitals and other health care facilities and compromised the ability of health care practitioners to provide necessary primary care. This article highlights the challenges and legal concerns faced by health care practitioners in the aftermath of Sandy, which included limitations in scope of practice, difficulties with credentialing, lack of portability of practitioner licenses, and concerns regarding volunteer immunity and liability. Governmental and nongovernmental entities employed various strategies to address these concerns; however, legal barriers remained that posed challenges throughout the Superstorm Sandy response and recovery period. We suggest future approaches to address these legal considerations, including policies and legislation, additional waivers of law, and planning and coordination among multiple levels of governmental and nongovernmental organizations. (Disaster Med Public Health Preparedness. 2016;10:518-524). PMID:27021812

  15. Did Hurricane Sandy influence the 2012 US presidential election?

    PubMed

    Hart, Joshua

    2014-07-01

    Despite drawing on a common pool of data, observers of the 2012 presidential campaign came to different conclusions about whether, how, and to what extent "October surprise" Hurricane Sandy influenced the election. The present study used a mixed correlational and experimental design to assess the relation between, and effect of, the salience of Hurricane Sandy on attitudes and voting intentions regarding President Barack Obama and Mitt Romney in a large sample of voting-aged adults. Results suggest that immediately following positive news coverage of Obama's handling of the storm's aftermath, Sandy's salience positively influenced attitudes toward Obama, but that by election day, reminders of the hurricane became a drag instead of a boon for the President. In addition to theoretical implications, this study provides an example of how to combine methodological approaches to help answer questions about the impact of unpredictable, large-scale events as they unfold. PMID:24767585

  16. Modern sedimentation and sediment dispersal pattern on the continental shelf off the Mekong River delta, South China Sea

    NASA Astrophysics Data System (ADS)

    Szczuciński, Witold; Jagodziński, Robert; Hanebuth, Till J. J.; Stattegger, Karl; Wetzel, Andreas; Mitręga, Marta; Unverricht, Daniel; Van Phach, Phung

    2013-11-01

    The Mekong River is one of the major suppliers of sediments to the ocean, resulting in the formation of one of the largest river deltas. A major portion of the supplied sediments is accumulated in the subaqueous delta front, which progrades directly off the river mouths and also forms at a distance of more than 200 km westward, next to the Camau Peninsula. This study presents evidence of the existence of a Mekong-fed prodelta further offshore and provides a first quantitative assessment of the modern fluvial-derived sediment dispersal pattern to the subaqueous prodelta, the outer continental shelf and the deep region of the South China Sea. The study is based on 96 surface shelf sediment samples and five short sediment cores, which were analyzed for grain-size composition, carbonate and total organic carbon contents, sedimentary structures (X-ray radiographs), clay mineralogy and bulk geochemistry as well as 210Pb and 137Cs-based sediment accumulation rates. The major sediment types in water depths of 18 m to 112 m include muddy sand, sand, gravelly muddy sand, sandy mud, gravelly sand and mud. The mud is composed mostly of silt fraction, while gravel is primarily composed of shell hash. The sedimentary structures include lamination, cross-stratification, truncation surfaces and burrows of various types. The carbonate content in the sediments varies from 3% close to the Mekong River mouths to 81% further on the shelf. Total organic carbon is from 0.02% in sand to 0.94% in mud. The highest average elemental concentrations are of Si, Ca, Al, Fe, Mg and K. The spatial variability is similar for Al, K and Ti, as well as for Ca and Sr, suggesting the common presence in phyllosilicates and calcium carbonate minerals, respectively. The most common clay mineral is illite followed by smectite, kaolinite and chlorite. The spatial distribution of clay minerals suggests that they are primarily derived from the Mekong River, except in the northeastern region. The sediment

  17. Sediment Sources in the Persian Gulf

    NASA Astrophysics Data System (ADS)

    Mahoutian, Mehrab

    2014-05-01

    Sediment Constituent Analysis is an effective tool for identifying sediment sources. Based on several sediment samples taken from different sites all over the Iranian coastlines, we have been able to show that an important portion of sediment on the beaches in the Persian Gulf is bio-clastic; that is, biologically created from the coral environment as well as other marine habitats. Unlike mineral (clastic) sediments, carbonate sediments are born not made. Furthermore, carbonate sand constituents are generally less durable than their quartz and mineral counterparts, and break down relatively quickly. Therefore, destruction of reefs and degradation of marine habitat are certain to reduce the sand supply to the shoreline in the Persian Gulf that is necessary to maintain beaches. Carbonate sands are also found on the coastline of the Oman Sea. One of the striking things about the sediments along the coastline of Iran is the high percentage of carbonate material. Molluscan debris is common, even ubiquitous. This reflects the populations living in the offshore waters. Some molluscs thrive in high-energy sandy environments, others like finer sediments. Some live at the surface, while some burrow down as much as a half-metre. A great deal of information can be gained from the study of the species of mollusk and their distribution in the sediments. This paper introduces a few case studies done in different parts of the Persian Gulf by using this method as a general assessment toolbox.

  18. Nutrient leaching from sediments according to different oxygen supplying conditions

    NASA Astrophysics Data System (ADS)

    Lee, J.; Park, J. I.; Choi, S. H.; Kim, K.

    2014-12-01

    To estimate the role of sediments controlling the water quality, many studies have adopted nutrient leaching experiments. However, the experiments were mostly performed under air-open condition, which is different from the actual condition at the bottom of fairly stagnant water body. Therefore, the results may not properly reflect the capability of the sediments supplying the nutrients to the water column. In this study, nutrient leaching experiments were conducted using various sediment samples under two different oxygen supplying conditions: one open and the other closed to the air. For this study, 5 sediment samples were collected from lakes and rivers around Kunsan, Korea. Air-closed leaching experiments were carried out using conventional BOD glass bottles (355 mL) without any head spaces. All the experiments were performed at a solid:solution ratio of 1:7.3. Each reactor was incubated at 25 ℃ for 72 hours or 120 hours. The solution was analyzed for pH, DO, Eh, NO3-N, NH4-N, and PO4-P after the incubation. Silt+clay fraction, total nitrogen (TN), total phosphorus (TP), and COD of the sediments showed close correlations with each other. Air-closed condition showed much higher leached concentrations for NH4-N and PO4-P (up to 60 times) than the air-open condition and the concentrations increased with the incubation time. However, the differences were very small in the experiments using sandy sediments (<0.13 mg/L and < 50 ug/L for NH4 and PO4 concentrations, respectively). In general, the leached NH4 and PO4 concentrations from the air-open experiments were not correlated well with the fine fractions due to nitrification and suppression of Fe-oxide reduction in aerobic condition, respectively. Because of this reason, some air-open results showed NO3-N concentrations higher than the concentrations obtained from the air-closed experiments. The experiments closed to air showed NO3-N concentrations substantially decreasing with the incubation time due to

  19. Interactive 4D Visualization of Sediment Transport Models

    NASA Astrophysics Data System (ADS)

    Butkiewicz, T.; Englert, C. M.

    2013-12-01

    Coastal sediment transport models simulate the effects that waves, currents, and tides have on near-shore bathymetry and features such as beaches and barrier islands. Understanding these dynamic processes is integral to the study of coastline stability, beach erosion, and environmental contamination. Furthermore, analyzing the results of these simulations is a critical task in the design, placement, and engineering of coastal structures such as seawalls, jetties, support pilings for wind turbines, etc. Despite the importance of these models, there is a lack of available visualization software that allows users to explore and perform analysis on these datasets in an intuitive and effective manner. Existing visualization interfaces for these datasets often present only one variable at a time, using two dimensional plan or cross-sectional views. These visual restrictions limit the ability to observe the contents in the proper overall context, both in spatial and multi-dimensional terms. To improve upon these limitations, we use 3D rendering and particle system based illustration techniques to show water column/flow data across all depths simultaneously. We can also encode multiple variables across different perceptual channels (color, texture, motion, etc.) to enrich surfaces with multi-dimensional information. Interactive tools are provided, which can be used to explore the dataset and find regions-of-interest for further investigation. Our visualization package provides an intuitive 4D (3D, time-varying) visualization of sediment transport model output. In addition, we are also integrating real world observations with the simulated data to support analysis of the impact from major sediment transport events. In particular, we have been focusing on the effects of Superstorm Sandy on the Redbird Artificial Reef Site, offshore of Delaware Bay. Based on our pre- and post-storm high-resolution sonar surveys, there has significant scour and bedform migration around the

  20. The Department of the Interior Strategic Sciences Group and its Response to Hurricane Sandy

    NASA Astrophysics Data System (ADS)

    Ludwig, K. A.; Machlis, G. E.; Applegate, D.

    2013-12-01

    the affected region and published an online peer-reviewed report on their results. Subsequently, the DOI used SSG findings to ensure supplemental investments for mitigation projects were prioritized to enhance regional resilience. The SSG is an innovative and flexible tool to support decision making that continues to evolve and show that it has applications across multiple phases of emergency management. The SSG methodology was developed during the Deepwater Horizon oil spill, when its predecessor, the Strategic Sciences Working Group (SSWG), convened to develop scenarios analyzing the cascading consequences of the spill on the Gulf of Mexico. The SSWG was deployed during the height of the emergency, when oil was still flowing from the broken pipe. By comparison, the recent deployment of the SSG was in Sandy's aftermath, when local, state, and federal institutions were focused on rebuilding efforts. Together, these deployments have enabled the SSG to assess its approach to scenario building during both emergency and recovery situations. The SSG continues to identify lessons learned from this experience to use in preparation for future deployments.

  1. Chemical Signals of Critical Zone Processing: Quantification of Water and Sediment Sources During Individual Storm Events in the Christina River Critical Zone Observatory

    NASA Astrophysics Data System (ADS)

    Karwan, D. L.; Aufdenkampe, A. K.; Aalto, R. E.; Lazareva, O.; Marquard, J.; Pizzuto, J. E.; Sawyer, A. H.

    2014-12-01

    Chemical signals of water and materials in catchment exports have long been studied as proxies for within-watershed processing. In the Christina River Critical Zone Observatory, we use the chemistry of water, in particular the oxygen-18 and chloride concentrations, and hydrograph separation to evaluate the contributions of different water sources to the stream discharge during a series of five storm events in 2011 and 2012. These events varied in magnitude, from 44 to 168 mm total precipitation, and precipitation chemistry, with δ18O values ranging from -5.38 to -11.06 ‰. The contribution of old water during the storm peak, determined by isotope hydrograph separation, varied from 0% in a spring storm of annual magnitude to 76% during Hurricane Sandy. Soil moisture data, available for all but one of our storms, indicates higher old water contribution at peak flow when the catchment has higher antecedent soil moisture. Understanding differences in water sourcing to the stream during different events provides a basis on which we analyze the movement of critical zone processing with regard to erosion and the source of exported sediment. For example, sediment fingerprinting with fallout radioisotopes indicated variation in sediment source between events. For example, suspended sediment samples taken during Hurricane Irene (28 August 2011) contained between 0 and 11.4 Bq/kg cesium-137 (137Cs) and 175 - 698 Bq/kg of beryllium-7 (7Be), indicating some level of recent surface erosion. Suspended sediment samples taken during Hurricane Sandy (29 October 2012) did not contain measureable activities of either 137Cs or 7Be.

  2. The Scientific and Institutional Context for the Removal of Marmot Dam, Sandy River, Oregon

    NASA Astrophysics Data System (ADS)

    Grant, G. E.; Major, J. J.; O'Connor, J.; Wallick, J. R.; Marr, J.; Wilcock, P.; Podolack, C.

    2008-12-01

    Dam removal has been widely viewed as an important river restoration strategy and an interesting scientific opportunity, the latter because it represents a real-time, full-scale field experiment on fluvial adjustment. Removals therefore offer an excellent setting for testing analytical models of sediment transport, morphologic change, and our capacity to predict short- and medium-term channel evolution in response to changing water and sediment transport regimes. Most dam removals to date have involved relatively small structures and modest releases of sediment stored in pre-removal reservoirs. The largest instantaneous and uncontrolled release of sediment accompanying a dam removal occurred with the breaching of the Marmot coffer dam on the Sandy River in Oregon in October 2007. Marmot Dam was a 14-m-high by 50-m-wide diversion dam built in 1913 as part of a larger hydroelectric project. It was located on the Sandy River, an energetic gravel to cobble-bed river that naturally carries copious quantities of sand and gravel, ~45 km upstream from its confluence with the Columbia River near Portland, Oregon. At the time of removal, the reservoir upstream of the dam was completely filled with ~750,000 m3 of sand (40%) and gravel (60%). The river below the dam includes bedrock gorges, mixed bedrock/alluvial reaches, and alluvial reaches with well-developed gravel and sand bars. The decision to remove the dam was motivated by a combination of increasing maintenance costs and an unfavorable future economic return due to the necessity of installing expensive fish passage facilities to meet relicensing requirements. Portland General Electric, the dam's owner, surrendered the dam's license in 1999, and removal commenced in summer 2007. To remove the concrete structure, a temporary coffer dam was constructed 70 m upstream. In October 2007 the coffer dam was breached and the river allowed to erode the remaining impounded sediment (~730,000 m3). Physical modeling conducted at

  3. Event-Based Monitoring of Sediment Flux Following Removal of Oregon's Marmot Dam

    NASA Astrophysics Data System (ADS)

    Major, J. J.; O'Connor, J. E.; Spicer, K. R.; Bragg, H. M.; Wallick, J. R.; Kittleson, R. L.; Lee, K. K.; Cushman, D.; Piatt, D.; Tanner, D. Q.; Hale, T.; Uhrich, M. A.; Rhode, A.

    2008-12-01

    Breaching of Oregon's Marmot Dam in October 2007 allowed the 80-km-long Sandy River to flow freely from Mount Hood to the Columbia River for the first time in nearly 100 years. When breached, the dam was brimful with sediment. As part of an analysis examining the redistribution of ~730,000 m3 of stored sediment following the dam removal, we measured suspended-sediment load and bedload at sites 10 km upstream and 0.5 to 18 km downstream of the dam before, during and after breaching, and during five subsequent high-water events. Prior to breaching of the dam, suspended-sediment and bedload mass fluxes along the Sandy River both upstream and downstream of the dam were of the order of a few to a few tens of kg/s. Suspended sediment upstream was composed chiefly of sand in contrast to mostly silt and clay passing measurement sites 0.5 and 18 km below the dam. In all reaches bedload consisted chiefly (>90%) of sand. Breaching of the dam released a pulse of turbid water having an instantaneous suspended-sediment flux of 5200 kg/s. The initial sediment pulse consisted predominantly of silt and clay, presumably eroded from thin, fine-grained topset beds at the downstream end of the reservoir. However, the suspended load coarsened rapidly as the Sandy River incised into the stored sand and gravel that filled the former reservoir. Following the initial peak value, median fluxes of sandy suspended sediment 0.5 km below the dam site hovered around several tens to hundreds of kg/s for at least 24 hours, whereas the median suspended- sediment flux remained about 30 kg/s both 10 km upstream and 18 km downstream. Bedload transport also increased following breaching, but its response was slower than for suspended sediment. Bedload flux 0.5 km below the dam site increased from ~1 kg/s before breaching to 60 kg/s by 6 hours and to about 70 kg/s by 18 hours after breaching, in contrast to the steady, low (<10 kg/s) flux of sandy bedload passing upstream and farther downstream before

  4. Response of coliform populations in streambed sediment and water column to changes in nutrient concentrations in water

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aims: The focus of this work was to observe the response of water column and sediment coliform population to the change in nutrient concentrations in the water column. Methods and Results: The survival experiments were conducted in flow-through chambers containing sandy sediments. Bovine faeces wer...

  5. Hurricane Sandy -- Pass 2, Oct. 29, 2012 - Duration: 2 minutes, 34 seconds.

    NASA Video Gallery

    Hurricane Sandy was viewed Monday morning from the International Space Station as it orbited 260 miles above the Atlantic Ocean. Sandy had sustained winds of 90 miles an hour as the station passed ...

  6. Coupled surface-subsurface hydrologic measurements reveal infiltration, recharge, and discharge dynamics across the swash zone of a sandy beach

    NASA Astrophysics Data System (ADS)

    Heiss, James W.; Puleo, Jack A.; Ullman, William J.; Michael, Holly A.

    2015-11-01

    Swash-groundwater interactions affect the biogeochemistry of beach aquifers and the transport of solutes and sediment across the beachface. Improved understanding of the complex, coupled dynamics of surface and subsurface flow processes in the swash zone is required to better estimate chemical fluxes to the sea and predict the morphological evolution of beaches. Simultaneous high-frequency measurements of saturation, water table elevation, and the cross-shore locations of runup and the boundary between the saturated and unsaturated beachface (surface saturation boundary) were collected on a sandy beach to link groundwater flow dynamics with swash zone forcing. Saturation and lysimeter measurements showed the dynamic response of subsurface saturation to swash events and permitted estimation of infiltration rates. Surface and subsurface observations revealed a decoupling of the surface saturation boundary and the intersection between the water table and the beachface. Surface measurements alone were insufficient to delineate the infiltration and discharge zones, which moved independently of the surface saturation boundary. Results show for the first time the motion and areal extent of infiltration and recharge zones, and constrain the maximum size of the subaerial discharge zone over swash and tidal time scales. The width of the infiltration zone was controlled by swash processes, and subaerial discharge was controlled primarily by tidal processes. These dynamics reveal the tightly coupled nature of surface and subsurface processes over multiple time scales, with implications for sediment transport and fluid and solute fluxes through the hydrologically and biogeochemically active intertidal zone of sandy beaches.

  7. Global diversity patterns in sandy beach macrofauna: a biogeographic analysis

    NASA Astrophysics Data System (ADS)

    Rafael Barboza, Francisco; Defeo, Omar

    2015-09-01

    Unlike the advances generated on land, the knowledge of global diversity patterns in marine ecosystems is limited to a small number of studies. For sandy beaches, which dominate the world’s ocean shores, previous meta-analyses highlighted the role of beach morphodynamics in explaining species richness patterns. Oceanographic variables and historical processes have not been considered, even though they could be main predictors of community structure. Our work, based on 256 sandy beaches around the world, analysed species richness considering for the first time temperature, salinity and primary productivity. Biogeographic units (realms, provinces and ecoregions) were used to incorporate historical factors in modelling processes. Ecoregions, which implicitly include isolation and coastal complexity among other historical geographic factors, best represented trends in species richness worldwide. Temperature was a main predictor of species richness, which increased from temperate to tropical sandy beaches. Species richness increased with tide range and towards wide beaches with gentle slopes and fine grains, which is consistent with the hypothesis that habitat availability has an important role in structuring sandy beach communities. The role of temperature and habitat availability suggests that ocean warming and sea level rise could affect the distribution of obligate species living in these narrow ecosystems.

  8. Hurricane Sandy: An Educational Bibliography of Key Research Studies

    ERIC Educational Resources Information Center

    Piotrowski, Chris

    2013-01-01

    There, undoubtedly, will be a flurry of research activity in the "Superstorm" Sandy impact area on a myriad of disaster-related topics, across academic disciplines. The purpose of this study was to review the disaster research related specifically to hurricanes in the educational and social sciences that would best serve as a compendium…

  9. FIELD SAMPLING OF RESIDUAL AVIATION GASOLINE IN SANDY SOIL

    EPA Science Inventory

    Two complimentary field sampling methods for the determination of residual aviation gasoline content in the contaminated capillary fringe of a fine, uniform, sandy soil were investigated. The first method featured filed extrusion of core barrels into pint size Mason jars, while ...

  10. Global diversity patterns in sandy beach macrofauna: a biogeographic analysis.

    PubMed

    Barboza, Francisco Rafael; Defeo, Omar

    2015-01-01

    Unlike the advances generated on land, the knowledge of global diversity patterns in marine ecosystems is limited to a small number of studies. For sandy beaches, which dominate the world's ocean shores, previous meta-analyses highlighted the role of beach morphodynamics in explaining species richness patterns. Oceanographic variables and historical processes have not been considered, even though they could be main predictors of community structure. Our work, based on 256 sandy beaches around the world, analysed species richness considering for the first time temperature, salinity and primary productivity. Biogeographic units (realms, provinces and ecoregions) were used to incorporate historical factors in modelling processes. Ecoregions, which implicitly include isolation and coastal complexity among other historical geographic factors, best represented trends in species richness worldwide. Temperature was a main predictor of species richness, which increased from temperate to tropical sandy beaches. Species richness increased with tide range and towards wide beaches with gentle slopes and fine grains, which is consistent with the hypothesis that habitat availability has an important role in structuring sandy beach communities. The role of temperature and habitat availability suggests that ocean warming and sea level rise could affect the distribution of obligate species living in these narrow ecosystems. PMID:26411697