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Sample records for marine pore waters

  1. Development and application of a marine sediment pore-water toxicity test using Ulva fasciata zoospores

    USGS Publications Warehouse

    Hooten, Russell L.; Carr, R. Scott

    1998-01-01

    An acute (96 h) pore-water toxicity test protocol using germination and growth of Ulva fasciatazoospores as endpoints was developed to test the toxicity of marine and estuarine sediment pore-water samples. Tests with an organic toxicant (sodium dodecyl sulfate; SDS), three metals (Cd, Cu, and Zn), and ammonia (NH3) were conducted to determine zoospore sensitivity. Zoospore germination and gametophyte growth were as sensitive to SDS as sea urchin (Arbacia punctulata) fertilization and embryological development. Zoospore sensitivity to metals was greater than or comparable to that of adult macroalgae. Zoospores were less sensitive to NH3than were other commonly used toxicity test organisms. Test results using this algal assay with sediment pore-water samples with high NH3 concentrations were compared with results from sea urchin fertilization and embryological development tests for the same samples. Ulva fasciatazoospore germination was not affected by samples with high NH3 concentrations that were toxic in both sea urchin tests. Zoospore tolerance of NH3 and sensitivity to other contaminants indicate that their response may be useful in toxicity identification evaluation studies with pore-water samples that contain high concentrations of unionized NH3.

  2. Development and application of a marine sediment pore-water toxicity test using Ulva fasciata zoospores

    SciTech Connect

    Hooten, R.L.; Carr, R.S.

    1998-01-01

    An acute (96 h) pore-water toxicity test protocol using germination and growth of Ulva fasciata zoospores as endpoints was developed to test the toxicity of marine and estuarine sediment pore-water samples. Tests with an organic toxicant (sodium dodecyl sulfate; SDS), three metals (Cd, Cu, and Zn), and ammonia (NH{sub 3}) were conducted to determine zoospore sensitivity. Zoospore germination and gametophyte growth were as sensitive to SDS as sea urchin (Arbacia punctulata) fertilization and embryological development. Zoospore sensitivity to metals was greater than or comparable to that of adult macroalgae. Zoospores were less sensitive to NH{sub 3} than were other commonly used toxicity test organisms. Test results using this algal assay with sediment pore-water samples with high NH{sub 3} concentrations were compared with results from sea urchin fertilization and embryological development tests for the same samples. Ulva fasciata zoospore germination was not affected by samples with high NH{sub 3} concentrations that were toxic in both sea urchin tests. Zoospore tolerance of NH{sub 3} and sensitivity to other contaminants indicate that their response may be useful in toxicity identification evaluation studies with pore-water samples that contain high concentrations of unionized NH{sub 3}.

  3. Variations of marine pore water salinity and chlorinity in Gulf of Alaska sediments (IODP Expedition 341)

    NASA Astrophysics Data System (ADS)

    März, Christian; Mix, Alan C.; McClymont, Erin; Nakamura, Atsunori; Berbel, Glaucia; Gulick, Sean; Jaeger, John; Schneider (LeVay), Leah

    2014-05-01

    Pore waters of marine sediments usually have salinities and chlorinities similar to the overlying sea water, ranging around 34-35 psu (Practical Salinity Units) and around 550 mM Cl-, respectively. This is because these parameters are conservative in the sense that they do not significantly participate in biogeochemical cycles. However, pore water studies carried out in the frame of the International Ocean Discovery Program (IODP) and its predecessors have shown that salinities and chlorinities of marine pore waters can substantially deviate from the modern bottom water composition in a number of environmental settings, and various processes have been suggested to explain these phenomena. Also during the recent IODP Expedition 341 that drilled five sites in the Gulf of Alaska (Northeast Pacific Ocean) from the deep Surveyor Fan across the continental slope to the glaciomarine shelf deposits, several occurrences of pore waters with salinities and chlorinities significantly different from respective bottom waters were encountered during shipboard analyses. At the pelagic Sites U1417 and U1418 (~4,200 and ~3,700 m water depth, respectively), salinity and chlorinity maxima occur around 20-50 m sediment depth, but values gradually decrease with increasing drilling depths (down to 30 psu in ~600 m sediment depth). While the pore water freshening at depth is most likely an effect of clay mineral dehydration due to increasing burial depth, the shallow salinity and chlorinity maxima are interpreted as relicts of more saline bottom waters that existed in the North Pacific during the Last Glacial Maximum (Adkins et al., 2002). In contrast, the glaciomarine slope and shelf deposits at Site U1419 to U1421 (~200 to 1,000 m water depth) are characterised by unexpectedly low salinitiy and chlorinity values (as low as 16 psu and 295 mM Cl-, respectively) already in very shallow sediment depths (~10 m), and their records do not show systematic trends with sediment depth. Freshening

  4. Precipitation of ikaite crystals in Antarctic marine sediments: implications from pore water geochemistry

    NASA Astrophysics Data System (ADS)

    Lu, Z.; Kennedy, H.; Rickaby, R. E.; Georg, B.; Shaw, S.; Lennie, A.; Pancost, R. D.

    2008-12-01

    Ikaite is a calcium carbonate hexahydrate (CaCO3•6H20) considered to be stable only at low temperatures. It has been found in form of tufa tower at locations where alkaline water mixes with water masses enriched in calcium (e.g. Ikka Fjord, Mono Lake). Large euhedral single crystals of ikaite were also recovered in marine sediments, associated with organic matter degradation, anaerobic oxidation of methane (AOM) and sulfate reduction. The hydration water in the ikaite crystals were demonstrated to record the oxygen isotope composition of the water from which they precipitated. Such a characteristic may allow using ikaite to reconstruct the ice volume in the past. For this purpose, the controls on its precipitation in the sediment column need to be investigated which is the main goal of this study. U.S. Antarctica Program cruise NBP0703 collected two cores with ikaite crystals at Antarctica Peninsula (Bransfield Strait and Firth of Tay). We determined major cation/anion concentrations, dissolved inorganic carbon (DIC) and δ13C composition of DIC in the pore waters in these two cores. Strong organic matter degradation or AOM in both cores results in quick consumption of sulfate in shallow part of the cores (SMT at around 3m).Rapid build-up of DIC is accompanied by the sharp decrease of dissolved calcium in the top 5m. Large variations were observed in δ13CDIC values (-20‰ to +13‰). The δ13C of ikaite in two cores were distinctive from each other (-19‰ and +4‰) corresponding to the DIC pools at different depths. The down core saturation state of the ikaite was modeled in PHREEQC based on the pore water chemistry, and the results are consistent with carbon isotope data, suggesting that these large crystals very likely formed within a narrow depth interval and a short time period (given high sedimentation rates of 0.5-1 cm/yr in this area).

  5. Stable silicon isotope signatures of marine pore waters - Biogenic opal dissolution versus authigenic clay mineral formation

    NASA Astrophysics Data System (ADS)

    Ehlert, Claudia; Doering, Kristin; Wallmann, Klaus; Scholz, Florian; Sommer, Stefan; Grasse, Patricia; Geilert, Sonja; Frank, Martin

    2016-10-01

    Dissolved silicon isotope compositions have been analysed for the first time in pore waters (δ30SiPW) of three short sediment cores from the Peruvian margin upwelling region with distinctly different biogenic opal content in order to investigate silicon isotope fractionation behaviour during early diagenetic turnover of biogenic opal in marine sediments. The δ30SiPW varies between +1.1‰ and +1.9‰ with the highest values occurring in the uppermost part close to the sediment-water interface. These values are of the same order or higher than the δ30Si of the biogenic opal extracted from the same sediments (+0.3‰ to +1.2‰) and of the overlying bottom waters (+1.1‰ to +1.5‰). Together with dissolved silicic acid concentrations well below biogenic opal saturation, our collective observations are consistent with the formation of authigenic alumino-silicates from the dissolving biogenic opal. Using a numerical transport-reaction model we find that approximately 24% of the dissolving biogenic opal is re-precipitated in the sediments in the form of these authigenic phases at a relatively low precipitation rate of 56 μmol Si cm-2 yr-1. The fractionation factor between the precipitates and the pore waters is estimated at -2.0‰. Dissolved and solid cation concentrations further indicate that off Peru, where biogenic opal concentrations in the sediments are high, the availability of reactive terrigenous material is the limiting factor for the formation of authigenic alumino-silicate phases.

  6. The marine geochemistry of actinium-227: Evidence for its migration through sediment pore water

    SciTech Connect

    Nozaki, Yoshiyuki; Yamada, Masatoshi ); Nikaido, Hirofumi )

    1990-10-01

    {sup 227}Ac with a half life of 21.8 years has a potential utility as a tracer of deep water circulation and mixing studies on time scales less than 100 years. Here the authors present the first measurement of {sup 227}Ac profile in the pore water of Northwest Pacific deep-sea sediment and in the {approximately}10,000 m long water column of Izu-Ogasawara Trench. The results clearly show that {sup 227}Ac is supplied from the sediment to the overlying water through migration in the pore water. The model calculation indicates that the molecular diffusion alone through sediment porewater can support only a half of the standing crop of excess {sup 227}Ac in the water column and the enhanced supply of {sup 227}Ac by particle mixing is necessary to account for the remainder. Thus, bioturbation in the deep sea plays an important role in controlling the flux of some short-lived radionuclides such as {sup 227}Ac and {sup 228}Ra across the sediment-water interface.

  7. Vitamin B1 in marine sediments: pore water concentration gradient drives benthic flux with potential biological implications

    PubMed Central

    Monteverde, Danielle R.; Gómez-Consarnau, Laura; Cutter, Lynda; Chong, Lauren; Berelson, William; Sañudo-Wilhelmy, Sergio A.

    2015-01-01

    Vitamin B1, or thiamin, can limit primary productivity in marine environments, however the major marine environmental sources of this essential coenzyme remain largely unknown. Vitamin B1 can only be produced by organisms that possess its complete synthesis pathway, while other organisms meet their cellular B1 quota by scavenging the coenzyme from exogenous sources. Due to high bacterial cell density and diversity, marine sediments could represent some of the highest concentrations of putative B1 producers, yet these environments have received little attention as a possible source of B1 to the overlying water column. Here we report the first dissolved pore water profiles of B1 measured in cores collected in two consecutive years from Santa Monica Basin, CA. Vitamin B1 concentrations were fairly consistent between the two years ranging from 30 pM up to 770 pM. A consistent maximum at ~5 cm sediment depth covaried with dissolved concentrations of iron. Pore water concentrations were higher than water column levels and represented some of the highest known environmental concentrations of B1 measured to date, (over two times higher than maximum water column concentrations) suggesting increased rates of cellular production and release within the sediments. A one dimensional diffusion-transport model applied to the B1 profile was used to estimate a diffusive benthic flux of ~0.7 nmol m−2 d−1. This is an estimated flux across the sediment-water interface in a deep sea basin; if similar magnitude B-vitamin fluxes occur in shallow coastal waters, benthic input could prove to be a significant B1-source to the water column and may play an important role in supplying this organic growth factor to auxotrophic primary producers. PMID:26029181

  8. Vitamin B1 in marine sediments: pore water concentration gradient drives benthic flux with potential biological implications.

    PubMed

    Monteverde, Danielle R; Gómez-Consarnau, Laura; Cutter, Lynda; Chong, Lauren; Berelson, William; Sañudo-Wilhelmy, Sergio A

    2015-01-01

    Vitamin B1, or thiamin, can limit primary productivity in marine environments, however the major marine environmental sources of this essential coenzyme remain largely unknown. Vitamin B1 can only be produced by organisms that possess its complete synthesis pathway, while other organisms meet their cellular B1 quota by scavenging the coenzyme from exogenous sources. Due to high bacterial cell density and diversity, marine sediments could represent some of the highest concentrations of putative B1 producers, yet these environments have received little attention as a possible source of B1 to the overlying water column. Here we report the first dissolved pore water profiles of B1 measured in cores collected in two consecutive years from Santa Monica Basin, CA. Vitamin B1 concentrations were fairly consistent between the two years ranging from 30 pM up to 770 pM. A consistent maximum at ~5 cm sediment depth covaried with dissolved concentrations of iron. Pore water concentrations were higher than water column levels and represented some of the highest known environmental concentrations of B1 measured to date, (over two times higher than maximum water column concentrations) suggesting increased rates of cellular production and release within the sediments. A one dimensional diffusion-transport model applied to the B1 profile was used to estimate a diffusive benthic flux of ~0.7 nmol m(-2) d(-1). This is an estimated flux across the sediment-water interface in a deep sea basin; if similar magnitude B-vitamin fluxes occur in shallow coastal waters, benthic input could prove to be a significant B1-source to the water column and may play an important role in supplying this organic growth factor to auxotrophic primary producers.

  9. Comparison of solid-phase and pore-water approaches for assessing the quality of marine and estuarine sediments

    USGS Publications Warehouse

    Carr, Robert Scott; Chapman, Duane C.

    1992-01-01

    As part of our continuing evaluation of the pore-water approach for assessing sediment quality, we made a series of side-by-side comparisons between the standard 10-day amphipod whole sediment test with the corophiid Grandidierella japonica and a suite of tests using pore water extracted from the same sediments. the pore-water tests evaluated were the sea urchin (Arbacia punctulata) sperm cell test and morphological development assay, the life-cycle test with the polychaete Dinophilus gyrociliatus, and acute exposures of red drum (Sciaenops ocellatus) embryo-larval stages. Sediment and surface microlayer samples were collected from contaminated sites. Whole-sediment, pore-water, and surface microlayer toxicity tests were performed. Pore-water toxicity tests were considerably more sensitive than the whole-sediment amphipod test, which is currently the most sensitive toxicity test now recommended for determining the acceptability of dredged material for open ocean disposal.

  10. Authigenic molybdenum formation in marine sediments: A link to pore water sulfide in the Santa Barbara Basin

    USGS Publications Warehouse

    Zheng, Yen; Anderson, Robert F.; VanGeen, A.; Kuwabara, J.

    2000-01-01

    Pore water and sediment Mo concentrations were measured in a suite of multicores collected at four sites along the northeastern flank of the Santa Barbara Basin to examine the connection between authigenic Mo formation and pore water sulfide concentration. Only at the deepest site (580 m), where pore water sulfide concentrations rise to >0.1 ??M right below the sediment water interface, was there active authigenic Mo formation. At shallower sites (550,430, and 340 m), where pore water sulfide concentrations were consistently <0.05 ??M, Mo precipitation was not occuring at the time of sampling. A sulfide concentration of ???0.1 ??M appears to be a threshold for the onset of Mo-Fe-S co-precipitation. A second threshold sulfide concentration of ???100 ??M is required for Mo precipitation without Fe, possibly as Mo-S or as particle-bound Mo. Mass budgets for Mo were constructed by combining pore water and sediment results for Mo with analyses of sediment trap material from Santa Barbara Basin as well as sediment accumulation rates derived from 210Pb. The calculations show that most of the authigenic Mo in the sediment at the deepest site is supplied by diffusion from overlying bottom waters. There is, however, a non-lithogenic particulate Mo associated with sinking particles that contributes ???15% to the total authigenic Mo accumulation. Analysis of sediment trap samples and supernant brine solutions indicates the presence of non-lithogenic particulate Mo, a large fraction of which is easily remobilized and, perhaps, associated with Mn-oxides. Our observations show that even with the very high flux of organic carbon reaching the sediment of Santa Barbara Basin, active formation of sedimentary authigenic Mo requires a bottom water oxygen concentration below 3 ??M. However, small but measurable rates of authigenic Mo accumulation were observed at sites where bottom water oxygen ranged between 5 and 23 ??M, indicating that the formation of authigenic Mo occured in the

  11. Extending electromagnetic methods to map coastal pore water salinities

    USGS Publications Warehouse

    Greenwood, Wm. J.; Kruse, S.; Swarzenski, P.

    2006-01-01

    The feasibility of mapping pore water salinity based on surface electromagnetic (EM) methods over land and shallow marine water is examined in a coastal wetland on Tampa Bay, Florida. Forward models predict that useful information on seabed conductivity can be obtained through <1.5 m of saline water, using floating EM-31 and EM-34 instruments from Geonics Ltd. The EM-31 functioned as predicted when compared against resistivity soundings and pore water samples and proved valuable for profiling in otherwise inaccessible terrain due to its relatively small size. Experiments with the EM-34 in marine water, however, did not reproduce the theoretical instrument response. The most effective technique for predicting pore water conductivities based on EM data entailed (1) computing formation factors from resistivity surveys and pore water samples at representative sites and (2) combining these formation factors with onshore and offshore EM-31 readings for broader spatial coverage. This method proved successful for imaging zones of elevated pore water conductivities/ salinities associated with mangrove forests, presumably caused by salt water exclusion by mangrove roots. These zones extend 5 to 10 m seaward from mangrove trunks fringing Tampa Bay. Modeling indicates that EM-31 measurements lack the resolution necessary to image the subtle pore water conductivity variations expected in association with diffuse submarine ground water discharge of fresher water in the marine water of Tampa Bay. The technique has potential for locating high-contrast zones and other pore water salinity anomalies in areas not accessible to conventional marine- or land-based resistivity arrays and hence may be useful for studies of coastal-wetland ecosystems. Copyright ?? 2005 National Ground Water Association.

  12. Mangrove pore water exchange across a latitudinal gradient

    NASA Astrophysics Data System (ADS)

    Tait, Douglas R.; Maher, Damien T.; Macklin, Paul A.; Santos, Isaac R.

    2016-04-01

    We combined observations of the natural tracer radon (222Rn) with hydrodynamic models across a broad latitudinal gradient covering several climate zones to estimate pore water exchange rates in mangroves. Pore water exchange ranged from 2.1 to 35.5 cm d-1 from temperate to tropical regions and averaged 16.3 ± 5.1 cm d-1. If upscaled to the global weighted mangrove area, pore water exchange in mangroves would recirculate the entire volume of water overlying the continental shelf in less than 153 years. Although pore water exchange (recirculated seawater) and river discharge represent different pathways for water entering the coastal ocean, the estimated global mangrove pore water exchange would be equal to approximately one third of annual global river discharge to the ocean (3.84 × 1013 m3 yr-1). Because biogeochemical processes in mangroves are largely dependent on pore water exchange, these large exchange rates have major implications for coastal nutrient, carbon, and greenhouse gas cycling in tropical marine systems.

  13. Pore Water Pumping by Upside-Down Jellyfish

    NASA Astrophysics Data System (ADS)

    Gaddam, Manikantam; Santhanakrishnan, Arvind

    2016-11-01

    Patchy aggregations of Cassiopea medusae, commonly called upside-down jellyfish, are found in sheltered marine environments with low-speed ambient flows. These medusae exhibit a sessile, non-swimming lifestyle, and are oriented such that their bells are attached to the substrate and oral arms point towards sunlight. Pulsations of their bells are used to generate currents for suspension feeding. Their pulsations have also been proposed to generate forces that can release sediment locked nutrients into the surrounding water. The goal of this study is to examine pore water pumping by Cassiopea individuals in laboratory aquaria, as a model for understanding pore water pumping in unsteady flows. Planar laser-induced fluorescence (PLIF) measurements were conducted to visualize the release of pore water via bell motion, using fluorescent dye introduced underneath the substrate. 2D particle image velocimetry (PIV) measurements were conducted on the same individuals to correlate PLIF-based concentration profiles with the jets generated by pulsing of medusae. The effects of varying bell diameter on pore water release and pumping currents will be discussed.

  14. Determination of 1-chloro-4-[2,2,2-trichloro-1-(4-chlorophenyl)ethyl]benzene and related compounds in marine pore water by automated thermal desorption-gas chromatography/mass spectrometry using disposable optical fiber

    USGS Publications Warehouse

    Eganhouse, Robert P.; DiFilippo, Erica L

    2015-01-01

    A method is described for determination of ten DDT-related compounds in marine pore water based on equilibrium solid-phase microextraction (SPME) using commercial polydimethylsiloxane-coated optical fiber with analysis by automated thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS). Thermally cleaned fiber was directly exposed to sediments and allowed to reach equilibrium under static conditions at the in situ field temperature. Following removal, fibers were rinsed, dried and cut into appropriate lengths for storage in leak-tight containers at -20°C. Analysis by TD-GC/MS under full scan (FS) and selected ion monitoring (SIM) modes was then performed. Pore-water method detection limits in FS and SIM modes were estimated at 0.05-2.4ng/L and 0.7-16pg/L, respectively. Precision of the method, including contributions from fiber handling, was less than 10%. Analysis of independently prepared solutions containing eight DDT compounds yielded concentrations that were within 6.9±5.5% and 0.1±14% of the actual concentrations in FS and SIM modes, respectively. The use of optical fiber with automated analysis allows for studies at high temporal and/or spatial resolution as well as for monitoring programs over large spatial and/or long temporal scales with adequate sample replication. This greatly enhances the flexibility of the technique and improves the ability to meet quality control objectives at significantly lower cost.

  15. Enhanced submarine ground water discharge form mixing of pore water and estuarine water

    USGS Publications Warehouse

    Martin, Jonathan B.; Cable, Jaye E.; Swarzenski, Peter W.; Lindenberg, Mary K.

    2004-01-01

    Submarine ground water discharge is suggested to be an important pathway for contaminants from continents to coastal zones, but its significance depends on the volume of water and concentrations of contaminants that originate in continental aquifers. Ground water discharge to the Banana River Lagoon, Florida, was estimated by analyzing the temporal and spatial variations of Cl− concentration profiles in the upper 230 cm of pore waters and was measured directly by seepage meters. Total submarine ground water discharge consists of slow discharge at depths > ∼70 cm below seafloor (cmbsf) of largely marine water combined with rapid discharge of mixed pore water and estuarine water above ∼70 cmbsf. Cl− profiles indicate average linear velocities of ∼0.014 cm/d at depths > ∼70 cmbsf. In contrast, seepage meters indicate water discharges across the sediment-water interface at rates between 3.6 and 6.9 cm/d. The discrepancy appears to be caused by mixing in the shallow sediment, which may result from a combination of bioirrigation, wave and tidal pumping, and convection. Wave and tidal pumping and convection would be minor because the tidal range is small, the short fetch of the lagoon limits wave heights, and large density contacts are lacking between lagoon and pore water. Mixing occurs to ∼70 cmbsf, which represents depths greater than previously reported. Mixing of oxygenated water to these depths could be important for remineralization of organic matter.

  16. Two-dimensional determination of dissolved iron and sulfur species in marine sediment pore-waters by thin-film based imaging. Thau lagoon (France)

    NASA Astrophysics Data System (ADS)

    Jézéquel, Didier; Brayner, Roberta; Metzger, Edouard; Viollier, Eric; Prévot, François; Fiévet, Fernand

    2007-04-01

    A device composed of a polyacrylamide gel thin-film (18 cm high, 5 cm wide and 0.4 mm thick) and a PVC (polyvinyl chloride) film was used as a sediment probe to obtain iron and S(-II) sulfur dissolved species' distributions in sediment pore waters. A porous protective membrane was set on top of hydrogel layer. Probes were deployed in May 2003 for 24-48 h in the superficial sediment of Thau lagoon (France), in a shellfish farming area. The polyacrylamide gel layer was used as a DET (Diffusive Equilibration in Thin-films) device for 2D Fe(II) concentration determination, and as the diffusive layer of a DGT-like (Diffusive Gradients in Thin-films) device for sulfur species study. The accumulation layer of the DGT device consisted in a PVC film layer underneath the polyacrylamide layer. Iron determinations were performed by colorimetric methods with Ferrozine and imaging technique. Image acquisitions were performed with a flatbed scanner. Fe(II) concentrations were deducted from densitometry analysis of the magenta zones (ImageJ software). The calibration curve was obtained by densitometry analysis of polyacrylamide gel pieces which were equilibrated in known iron (II) concentration solutions. ΣFe distribution was performed but not quantified. Analysis of gray zones on the PVC layer provided a qualitative distribution of unidentified S(-II) dissolved compounds, related to H 2S zone for which information is obtained by classical methods (peeper and colorimetric measurements). EDX (X-ray energy dispersive spectrometry) and GIXR (Grazing-Incidence X-ray Diffraction) analyses of gray zone of this PVC layer provide evidence for FeS 2 catalyzed precipitation onto this film. Dissolved Fe(II) was mainly located near the sediment-water interface (SWI), showing a nonhomogeneous layer about 10 mm thick. Small Fe rich domains appeared deeper in the sediment and likely confirm newest paradigms in the field of sediment biogeochemistry. S(-II) species are detected from 3 to 4 cm

  17. Displacement of soil pore water by trichloroethylene

    USGS Publications Warehouse

    Wershaw, R. L.; Aiken, G.R.; Imbrigiotta, T.E.; Goldberg, M.C.

    1994-01-01

    Dense nonaqueous phase liquids (DNAPLS) are important pollutants because of their widespread use as chemical and industrial solvents. An example of the pollution caused by the discharge of DNAPLs is found at the Picatinny Arsenal, New Jersey, where trichloroethylene (TCE) has been discharged directly into the unsaturated zone. This discharge has resulted in the formation of a plume of TCE-contaminated water in the aquifer downgradient of the discharge. A zone of dark-colored groundwater containing a high dissolved organic C content has been found near the point of discharge of the TCE. The colored-water plume extends from the point of discharge at least 30 m (100 feet) downgradient. Fulvic acids isolated from the colored-waters plume, from water from a background well that has not been affected by the discharge of chlorinated solvents, and from soil pore water collected in a lysimeter installed at an uncontaminated site upgradient of the study area have been compared. Nuclear magnetic resonance spectra of the fulvic acids from the colored waters and from the lysimeter are very similar, but are markedly different from the nuclear magnetic resonance spectrum of the fulvic acid from the background well. The three-dimensional fluorescence spectrum and the DOC fractionation profile of the colored groundwater and the soil pore water are very similar to each other, but quite different from those of the background water. It is proposed from these observations that this colored water is soil pore water that has been displaced by a separate DNAPL liquid phase downward to the saturated zone.

  18. Displacement of soil pore water by trichloroethylene

    SciTech Connect

    Wershaw, R.L.; Aiken, G.R.; Imbrigiotta, T.E.

    1994-07-01

    Dense nonaqueous phase liquids (DNAPLS) are important pollutants because of their widespread use as chemical and industrial solvents. An example of the pollution caused by the discharge of DNAPLs is found at the Picatinny Arsenal, New Jersey, where trichloroethylene (TCE) has been discharged directly into the unsaturated zone. This discharge has resulted in the formation of a plume of TCE-contaminated water in the aquifer downgradient of the discharge. A zone of dark-colored groundwater containing a high dissolved organic C content has been found near the point of discharge of the TCE. The colored-water plume extends from the point of discharge at least 30 m (100 feet) downgradient. Fulvic acids isolated from the colored-waters plume, from water from a background well that has not been affected by the discharge of chlorinated solvents, and from soil pore water collected in a lysimeter installed at an uncontaminated site upgradient of the study area have been compared. Nuclear magnetic resonance spectra of the fulvic acids from the colored waters and from the lysimeter am very similar, but are markedly different from the nuclear magnetic resonance spectrum of the fulvic acid from the background well. The three-dimensional fluorescence spectrum and the DOC fractionation profile of the colored groundwater and the soil pore water are very similar to each other, but quite different from those of the background water. It is proposed from these observations that this colored water is soil pore water that has been displaced by a separate DNAPL liquid phase downward to the saturated zone. 15 refs., 6 figs., 4 tabs.

  19. Pore networks in continental and marine mudstones: Characteristics and controls on sealing behavior

    USGS Publications Warehouse

    Heath, J.E.; Dewers, T.A.; McPherson, B.J.O.L.; Petrusak, R.; Chidsey, T.C.; Rinehart, A.J.; Mozley, P.S.

    2011-01-01

    Mudstone pore networks are strong modifiers of sedimentary basin fluid dynamics and have a critical role in the distribution of hydrocarbons and containment of injected fluids. Using core samples from continental and marine mudstones, we investigate properties of pore types and networks from a variety of geologic environments, together with estimates of capillary beam- scanning electron microscopy, suggest seven dominant mudstone pore types distinguished by geometry and connectivity. A dominant planar pore type occurs in all investigated mudstones and generally has high coordination numbers (i.e., number of neighboring connected pores). Connected networks of pores of this type contribute to high mercury capillary pressures due to small pore throats at the junctions of connected pores and likely control most matrix transport in these mudstones. Other pore types are related to authigenic (e.g., replacement or pore-lining precipitation) clay minerals and pyrite nodules; pores in clay packets adjacent to larger, more competent clastic grains; pores in organic phases; and stylolitic and microfracture-related pores. Pores within regions of authigenic clay minerals often form small isolated networks (<3 ??m). Pores in stringers of organic phases occur as tubular pores or slit- and/or sheet-like pores. These form short, connected lengths in 3D reconstructions, but appear to form networks no larger than a few microns in size. Sealing efficiency of the studied mudstones increases with greater distal depositional environments and greater maximum depth of burial. ?? 2011 Geological Society of America.

  20. Differences in soluble organic carbon chemistry in pore waters sampled from different pore size domains

    DOE PAGES

    Bailey, Vanessa L.; Smith, A. P.; Tfaily, Malak; ...

    2017-01-11

    Spatial isolation of soil organic carbon (SOC) in different sized pores may be a mechanism by which otherwise labile carbon (C) could be protected in soils. When soil water content increases, the hydrologic connectivity of soil pores also increases, allowing greater transport of SOC and other resources from protected locations, to microbially colonized locations more favorable to decomposition. The heterogeneous distribution of specialized decomposers, C, and other resources throughout the soil indicates that the metabolism or persistence of soil C compounds is highly dependent on short-distance transport processes. The objective of this research was to characterize the complexity of Cmore » in pore waters held at weak and strong water tensions (effectively soil solution held behind coarse- and fine-pore throats, respectively) and evaluate the microbial decomposability of these pore waters. We saturated intact soil cores and extracted pore waters with increasing suction pressures to sequentially sample pore waters from increasingly fine pore domains. Ultrahigh resolution mass spectrometry of the SOC was used to profile the major biochemical classes (i.e., lipids, proteins, lignin, carbohydrates, and condensed aromatics) of compounds present in the pore waters; some of these samples were then used as substrates for growth of Cellvibrio japonicus (DSMZ 16018), Streptomyces cellulosae (ATCC® 25439™), and Trichoderma reseei (QM6a) in 7 day incubations. The soluble C in finer pores was more complex than the soluble C in coarser pores, and the incubations revealed that the more complex C in these fine pores is not recalcitrant. The decomposition of this complex C led to greater losses of C through respiration than the simpler C from coarser pore waters. Our research suggests that soils that experience repeated cycles of drying and wetting may be accompanied by repeated cycles of increased CO2 fluxes that are driven by i) the transport of C from protected pools into

  1. Hydrochemical reactions and origin of offshore relatively fresh pore water from core samples in Hong Kong

    NASA Astrophysics Data System (ADS)

    Kwong, Hiu Tung; Jiao, Jiu Jimmy

    2016-06-01

    The existence of relatively fresh pore water offshore has been well recognised over the globe but studies on the chemistry of the pore water from offshore geological formations are extremely limited. This study aims to characterize the hydrochemistry of the submarine groundwater body in Hong Kong. It looks into the major ion concentrations and the stable isotopic compositions of pore water extracted from core samples from an offshore 42.30-m vibrocore in the southwestern Hong Kong waters. A minimum Cl- level of about one-third of that in typical seawater was noted in the terrestrial sediments, suggesting the presence of offshore relatively fresh water. Unexpectedly high NH4+ levels are attributed to organic matter decomposition in the terrestrial sediments. The leaching of shells due to exposure of marine sediments at sea-level low stands raises the Mg2+ and Ca2+ concentrations. Base Exchange Indices show weak cation exchange reactions in which Na+ and K+ are released while Mg2+ and Ca2+ are adsorbed. Isotopic compositions of pore water reveal that the low-salinity water is probably the relic water sequestered in fluvial systems during relative sea-level low stands. Cores properly stored in a freezer for a long time has been used to study the pore water chemistry. For the first time, this study introduces an approach to correct the measured data by considering the possible evaporation effect during the transportation and storage of the samples. Corrections for evaporation were applied to the major ion concentrations and the stable isotopic compositions of pore water measured. It is found that the corrections determined by the Cl- mass balance approach are more reliable. The corrected measurements give more reasonable observations and hence allow sensible conclusions on the hydrochemical reactions and the origin of pore water.

  2. The ability of rock physics models to infer marine in situ pore pressure

    NASA Astrophysics Data System (ADS)

    Hornbach, Matthew J.; Manga, Michael

    2014-12-01

    fluid pressure is an important parameter defining the mechanical strength of marine sediments. Obtaining high spatial resolution in situ pore pressure measurements in marine sediments, however, is a challenge, and as a result, only a handful of in situ pore pressure measurements exist at scientific drill sites. Integrating rock physics models with standard IODP/ODP measurements provides a potentially widely applicable approach for calculating in situ pore pressure. Here we use a rock physics approach to estimate in situ pore pressure at two Scientific Ocean Drill Sites where in situ pressure is well constrained: ODP Site 1173, used as reference for normal (hydrostatic) fluid pressures, and ODP Site 948, where previous studies infer high fluid pressures (λ* ˜ 0.45-0.95, where the pore pressure ratio λ* is defined as the pore pressure above hydrostatic divided by the difference between the largest principal stress and hydrostatic stress). Our analysis indicates that the rock physics method provides an accurate, low-precision method for estimating in situ pore pressure at these drill sites, and sensitivity analysis indicates this method can detect modestly high (λ* > 0.6) pore pressure at the 95% confidence level. This approach has broad applicability because it provides an inexpensive, high-resolution (meter-scale) method for retrospectively detecting and quantifying high pore pressure at any drill site where quality wireline logs and ocean drilling data exist.

  3. Effects of salinity variations on pore water flow in salt marshes

    NASA Astrophysics Data System (ADS)

    Shen, Chengji; Jin, Guangqiu; Xin, Pei; Kong, Jun; Li, Ling

    2015-06-01

    Spatial and temporal salinity variations in surface water and pore water commonly exist in salt marshes under the combined influence of tidal inundation, precipitation, evapotranspiration, and inland freshwater input. Laboratory experiments and numerical simulations were conducted to investigate how density gradients associated with salinity variations affect pore water flow in the salt marsh system. The results showed that upward salinity (density) gradients could lead to flow instability and the formation of salt fingers. These fingers, varying in size with the distance from the creek, modified significantly the pore water flow field, especially in the marsh interior. While the flow instability enhanced local salt transport and mixing considerably, the net effect was small, causing only a slight increase in the overall mass exchange across the marsh surface. In contrast, downward salinity gradients exerted less influence on the pore water flow in the marsh soil and slightly weakened the surface water and groundwater exchange across the marsh surface. Numerical simulations revealed similar density effects on pore water flow at the field scale under realistic conditions. These findings have important implications for studies of marsh soil conditions concerning plant growth as well as nutrient exchange between the marsh and coastal marine system.

  4. Marine Biodiversity in Japanese Waters

    PubMed Central

    Fujikura, Katsunori; Lindsay, Dhugal; Kitazato, Hiroshi; Nishida, Shuhei; Shirayama, Yoshihisa

    2010-01-01

    To understand marine biodiversity in Japanese waters, we have compiled information on the marine biota in Japanese waters, including the number of described species (species richness), the history of marine biology research in Japan, the state of knowledge, the number of endemic species, the number of identified but undescribed species, the number of known introduced species, and the number of taxonomic experts and identification guides, with consideration of the general ocean environmental background, such as the physical and geological settings. A total of 33,629 species have been reported to occur in Japanese waters. The state of knowledge was extremely variable, with taxa containing many inconspicuous, smaller species tending to be less well known. The total number of identified but undescribed species was at least 121,913. The total number of described species combined with the number of identified but undescribed species reached 155,542. This is the best estimate of the total number of species in Japanese waters and indicates that more than 70% of Japan's marine biodiversity remains un-described. The number of species reported as introduced into Japanese waters was 39. This is the first attempt to estimate species richness for all marine species in Japanese waters. Although its marine biota can be considered relatively well known, at least within the Asian-Pacific region, considering the vast number of different marine environments such as coral reefs, ocean trenches, ice-bound waters, methane seeps, and hydrothermal vents, much work remains to be done. We expect global change to have a tremendous impact on marine biodiversity and ecosystems. Japan is in a particularly suitable geographic situation and has a lot of facilities for conducting marine science research. Japan has an important responsibility to contribute to our understanding of life in the oceans. PMID:20689840

  5. Pore Water Transport of Enterococci out of Beach Sediments

    PubMed Central

    Phillips, Matthew C.; Solo-Gabriele, Helena M.; Reniers, Adrianus J. H. M.; Wang, John D.; Kiger, Russell T.; Abdel-Mottaleb, Noha

    2011-01-01

    Enterococci are used to evaluate the safety of beach waters and studies have identified beach sands as a source of these bacteria. In order to study and quantify the release of microbes from beach sediments, flow column systems were built to evaluate flow of pore water out of beach sediments. Results show a peak in enterococci (average of 10% of the total microbes in core) released from the sand core within one pore water volume followed by a marked decline to below detection. These results indicate that few enterococci are easily removed and that factors other than simple pore water flow control the release of the majority of enterococci within beach sediments. A significantly larger quantity and release of enterococci were observed in cores collected after a significant rain event suggesting the influx of fresh water can alter the release pattern as compared to cores with no antecedent rainfall. PMID:21945015

  6. Deep Water, Shallow Water: Marine Animal Homes.

    ERIC Educational Resources Information Center

    Soltow, Willow

    1984-01-01

    Examines the diversity of life in the oceans and ways in which teachers can explore ocean habitats with their students without leaving the classroom. Topic areas considered include: restricted habitats, people and marine habitats, pollution, incidental kills, and the commercial and recreational uses of marine waters. (JN)

  7. Benthic invertebrate bioassays with toxic sediment and pore water

    USGS Publications Warehouse

    Giesy, John P.; Rosiu, Cornell J.; Graney, Robert L.; Henry, Mary G.

    1990-01-01

    The relative sensitivities of bioassays to determine the toxicity of sediments were investigated and three methods of making the sample dilutions required to generate dose-response relationships were compared. The assays studied were: (a) Microtox®, a 15-min assay ofPhotobacterium phosphoreum bioluminescence inhibition by pore water; (b) 48-h Daphnia magnalethality test in pore water; (c) 10-d subchronic assay of lethality to and reduction of weight gain by Chironomus tentans performed in either whole sediment or pore water; (d) 168-h acute lethality assay of Hexagenia limbata in either whole sediment or pore water. The three methods of diluting sediments were: (a) extracting pore water from the toxic location and dilution with pore water from the control station; (b) diluting whole sediment from the toxic location with control whole sediment from a reference location, then extracting pore water; and (c) diluting toxic, whole sediment with whole sediment from a reference location, then using the whole sediment in bioassays. Based on lethality, H. limbata was the most sensitive organism to the toxicity of Detroit River sediment. Lethality of D. magna in pore water was similar to that of H. limbata in whole sediment and can be used to predict effects of whole sediment toxicity to H. limbata. The concentration required to cause a 50% reduction in C. tentans growth (10-d EC50) was approximately that which caused 50% lethality of D. magna (48-h LC50) and was similar to the toxicity that restricts benthic invertebrate colonization of contaminated sediments. While the three dilution techniques gave similar results with some assays, they gave very different results in other assays. The dose-response relationships determined by the three dilution techniques would be expected to vary with sediment, toxicant and bioassay type, and the dose-response relationship derived from each technique needs to be interpreted accordingly.

  8. Evaporation of Topopah Spring tuff pore water

    SciTech Connect

    Dibley, M J; Knauss, K G; Rosenberg, N D

    1999-09-10

    We report on the results to date for experiments on the evaporative chemical evolution of a CaSO, rich water representative of Topopah Spring Tuff porewater from Yucca Mountain. Data include anion and cation analysis and qualitative mineral identification for a series of open system experiments, with and without crushed tuff present, conducted at sub-boiling temperatures.

  9. Slow Desorption of Phenanthrene from Silica Particles: Influence of Pore Size, Pore Water, and Aging Time

    SciTech Connect

    Huesemann, Michael H.; Fortman, Timothy J.; Riley, Robert G.; Thompson, Christopher J.; Wang, Zheming; Truex, Michael J.; Peyton, Brent M.

    2006-01-16

    When micro-porous and meso-porous silica particles were exposed to aqueous phenanthrene solutions for various durations it was observed that sorbed-phase phenanthrene concentrations increased with aging time only for meso-porous but not micro-porous silicas. Desorption equilibrium was reached almost instantaneously for the micro-porous particles while both the rate and extent of desorption decreased with increasing aging time for the meso-porous silicas. These findings indicate that phenanthrene can be sequestered within the internal pore-space of meso-porous silicas while the internal surfaces of micro-porous silicas are not accessible to phenanthrene sorption, possibly due to the presence of physi- or chemi-sorbed water that may sterically hinder the diffusion of phenanthrene inside water-filled micro-pores. By contrast, the internal surfaces of these micro-porous silicas are accessible to phenanthrene when aging methods are employed which assure that pores are devoid of physi-sorbed water. Consequently, when phenanthrene was incorporated into these particles using either supercritical CO2 or via solvent soaking, the aqueous desorption kinetics were extremely slow indicating effective sequestration of phenanthrene inside micro-porous particles. Finally, a two-compartment conceptual model is used to interpret the experimental findings.

  10. Unstable Pore-Water Flow in Intertidal Wetlands

    NASA Astrophysics Data System (ADS)

    Barry, D. A.; Shen, C.; Li, L.

    2014-12-01

    Salt marshes are important intertidal wetlands strongly influenced by interactions between surface water and groundwater. Bordered by coastal water, the marsh system undergoes cycles of inundation and exposure driven by the tide. This leads to dynamic, complex pore-water flow and solute transport in the marsh soil. Pore-water circulations occur over vastly different spatial and temporal scales with strong link to the marsh topography. These circulations control solute transport between the marsh soil and the tidal creek, and ultimately affect the overall nutrient exchange between the marsh and coastal water. The pore-water flows also dictate the soil condition, particularly aeration, which influences the marsh plant growth. Numerous studies have been carried out to examine the pore-water flow process in the marsh soil driven by tides, focusing on stable flow with the assumption of homogeneity in soil and fluid properties. This assumption, however, is questionable given the actual inhomogeneous conditions in the field. For example, the salinity of surface water in the tidal creek varies temporally and spatially due to the influence of rainfall and evapotranspiration as well as the freshwater input from upland areas to the estuary, creating density gradients across the marsh surface and within the marsh soil. Many marshes possess soil stratigraphy with low-permeability mud typically overlying high-permeability sandy deposits. Macropores such as crab burrows are commonly distributed in salt marsh sediments. All these conditions are prone to the development of non-uniform, unstable preferential pore-water flow in the marsh soil, for example, funnelling and fingering. Here we present results from laboratory experiments and numerical simulations to explore such unstable flow. In particular, the analysis aims to address how the unstable flow modifies patterns of local pore-water movement and solute transport, as well as the overall exchange between the marsh soil and

  11. Molecular characterization of dissolved organic matter in pore water of continental shelf sediments

    NASA Astrophysics Data System (ADS)

    Schmidt, Frauke; Elvert, Marcus; Koch, Boris P.; Witt, Matthias; Hinrichs, Kai-Uwe

    2009-06-01

    Dissolved organic matter (DOM) in sediment pore water is a complex molecular mixture reflecting various sources and biogeochemical processes. In order to constrain those sources and processes, molecular variations of pore water DOM in surface sediments from the NW Iberian shelf were analyzed by ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and compared to river and marine water column DOM. Weighted average molecular element ratios of oxygen to carbon ((O/C) wa) and hydrogen to carbon ((H/C) wa) provided general information about DOM sources. DOM in local rivers was more oxygenated ((O/C) wa 0.52) and contained less hydrogen ((H/C) wa 1.15) than marine pore water DOM (mean (O/C) wa 0.50, mean (H/C) wa 1.26). The relative abundance of specific compound groups, such as highly oxygenated aromatic compounds or nitrogen-bearing compounds with low H/C ratios, correspond to a high concentration of lignin phenols (160 μg/g sediment dry weight) and a high TOC/TN ratio (13.3) in the sedimentary organic matter and were therefore assigned to terrestrial sources. The lower degree of unsaturation and a higher relative abundance of nitrogen-bearing compounds in the pore water DOM reflected microbial activity within the sediment. One sampling site on the shelf with a high sediment accumulation, and a humic-rich river sample showed a wide range of sulfur compounds in the DOM, accompanied by a higher abundance of lipid biomarkers for sulfate-reducing bacteria, probably indicating early diagenetic sulfurization of organic matter.

  12. Carbon and nitrogen stoichiometry regulates the magnitude and temporal dynamics of nitrogenous nutrient regeneration in sandy beach pore water

    NASA Astrophysics Data System (ADS)

    Goodridge, B. M.; Melack, J. M.

    2013-12-01

    Sandy beaches are located at the interface of terrestrial and marine ecosystems, lining about 70% of the world's ice-free coastline. They can be conduits for fresh groundwater delivery of dissolved inorganic nitrogen (DIN), a vital and often limiting nutrient source, to oceans along coastlines where a hydrologic connection exists with shallow coastal aquifers. However, even along such coastlines, the majority of water within beach sands is recirculated seawater (i.e., pore water), and the regeneration of DIN from the mineralization of marine organic matter (OM) is considered the dominant source of DIN in beach pore water and flux to coastal oceans. The biogeochemical mechanisms regulating the magnitude of and temporal changes in DIN regeneration in saline beach pore water are therefore of prime importance in assessing the role of beaches in coastal marine nitrogen cycling. We assessed the potential stoichiometric control of resource carbon to nitrogen (C:N) on pore water DIN regeneration at four sandy beach study locations, and temporal evolution of pore water C:N at two of the four study locations, along the Santa Barbara, California coastline during synoptic sampling events over the course of a year. We identified pore water dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) as the resources most likely available to microbial heterotrophic metabolism (i.e., C:N), the dominant catalyst of DIN regeneration in marine sediments, finding a negative exponential correlation of DIN with DOC:TDN ratios (673 × 173 e-1.05 × 0.30(DOC:TDN); R2 = 0.55, n = 123). DOC:TDN ratios also demonstrated a negative exponential correlation with residence time (10.0 × 1.7 e-1.08 × 0.48(RT) + 1.61 × 0.54; R2 = 0.79, n = 46), estimated using radon-222 as a pore water residence time tracer. Using model-derived DOC:TDN ratios as the independent variable in the DIN vs. DOC:TDN relationship, we explored temporal changes in DIN regeneration. The modeled DIN vs. residence time

  13. Occurrence of arsenic in sediment pore waters in the central Kanto Plain, Japan

    NASA Astrophysics Data System (ADS)

    Hachinohe, Shoichi; Hamamoto, Hideki; Ishiyama, Takashi; Hossain, Sushmita; Oguchi, Chiaki T.

    2014-05-01

    The Kanto Plain is known as the largest plain in Japan, where marine sediments are widely developed because of cyclic iteration of global sea-level changes even 50 km or more inland from the present shoreline. In this area, dependence on groundwater for water requirements is relatively high; in particular, around 40 % of the municipal water supply is dependent on groundwater. Arsenic levels greater than that permitted by the environmental standards of Japan have been detected in groundwater in this area. Therefore, to evaluate occurrences of arsenic and other related elements in pore waters contained in natural sediment layers, we measured the levels of various inorganic chemical substances such as arsenic (As), iron (Fe), and sulfur (S) and major dissolved ions such as sulfate (SO42-), calcium (Ca2+), and sodium (Na+). Pore waters were collected from sediment samples that were obtained by a drilling from the river bottom down to 44 m depth; pore water samples were obtained immediately after extraction of sediments. The sedimentary facies in the vertical profile are continental, transitional, and marine, including two aquifers. The upper aquifer (15-20 m) contains fine to medium sand, whereas the lower aquifer (37-44 m) contains medium to coarse and gravelly sand. Arsenic and other inorganic elements were measured by an inductively coupled plasma mass spectrometer (ICP/MS) and an inductively coupled plasma atomic emission spectrometer (ICP/AES), and major dissolved ions were measured by an ion chromatograph analyzer. The total content of chemical elements was measured by X-ray fluorescence analysis using solid sediment samples. We obtained the following results. The arsenic concentrations in pore waters in marine silt and clay sediments (approximately 0.04 mg/L) were about five times higher than that in continental sediments (approximately 0.008 mg/L). The highest concentration of arsenic (0.074 mg/L) was detected at a depth of 13 m, which is immediately above the

  14. Pore connectivity, electrical conductivity, and partial water saturation: Network simulations

    NASA Astrophysics Data System (ADS)

    Li, M.; Tang, Y. B.; Bernabé, Y.; Zhao, J. Z.; Li, X. F.; Bai, X. Y.; Zhang, L. H.

    2015-06-01

    The electrical conductivity of brine-saturated rock is predominantly dependent on the geometry and topology of the pore space. When a resistive second phase (e.g., air in the vadose zone and oil/gas in hydrocarbon reservoirs) displaces the brine, the geometry and topology of the pore space occupied by the electrically conductive phase are changed. We investigated the effect of these changes on the electrical conductivity of rock partially saturated with brine. We simulated drainage and imbibition as invasion and bond percolation processes, respectively, in pipe networks assumed to be perfectly water-wet. The simulations included the formation of a water film in the pipes invaded by the nonwetting fluid. During simulated drainage/imbibition, we measured the changes in resistivity index as well as a number of relevant microstructural parameters describing the portion of the pore space saturated with water. Except Euler topological number, all quantities considered here showed a significant level of "universality," i.e., insensitivity to the type of lattice used (simple cubic, body-centered cubic, or face-centered cubic). Hence, the coordination number of the pore network appears to be a more effective measure of connectivity than Euler number. In general, the simulated resistivity index did not obey Archie's simple power law. In log-log scale, the resistivity index curves displayed a substantial downward or upward curvature depending on the presence or absence of a water film. Our network simulations compared relatively well with experimental data sets, which were obtained using experimental conditions and procedures consistent with the simulations. Finally, we verified that the connectivity/heterogeneity model proposed by Bernabé et al. (2011) could be extended to the partial brine saturation case when water films were not present.

  15. Toxicity of sediments and pore water from Brunswick Estuary, Georgia

    USGS Publications Warehouse

    Winger, Parley V.; Lasier, Peter J.; Geitner, Harvey

    1993-01-01

    A chlor-alkali plant in Brunswick, Georgia, USA, discharged >2 kg mercury/d into a tributary of the Turtle River-Brunswick Estuary from 1966 to 1971. Mercury concentrations in sediments collected in 1989 along the tributary near the chlor-alkali plant ranged from 1 to 27 μg/g (dry weight), with the highest concentrations found in surface (0–8 cm) sediments of subtidal zones in the vicinity of the discharge site. Toxicity screening in 1990 using Microtox® bioassays on pore water extracted on site from sediments collected at six stations distributed along the tributary indicated that pore water was highly toxic near the plant discharge. Ten-day toxicity tests on pore water from subsequent sediment samples collected near the plant discharge confirmed high toxicity to Hyalella azteca, and feeding activity was significantly reduced in whole-sediment tests. In addition to mercury in the sediments, other metals (chromium, lead, and zinc) exceeded 50 μg/g, and polychlorobiphenyl (PCB) concentrations ranged from 67 to 95 μg/g. On a molar basis, acid-volatile sulfide concentrations (20–45 μmol/g) in the sediments exceeded the metal concentrations. Because acid-volatile sulfides bind with cationic metals and form metal sulfides, which are generally not bioavailable, toxicities shown by these sediments were attributed to the high concentrations of PCBs and possibly methylmercury.

  16. Hydrogeology and hydrodynamics of coral reef pore waters

    SciTech Connect

    Buddemeier, R.W.; Oberdorfer, J.A.

    1988-06-29

    A wide variety of forces can produce head gradients that drive the flow and advective mixing of internal coral reef pore waters. Oscillatory gradients that produce mixing result from wave and tide action. Sustained gradients result from wave and tide-induced setup and ponding, from currents impinging on the reef structure, from groundwater heads, and from density differenced (temperature or salinity gradients). These gradients and the permeabilities and porosities of reef sediments are such that most macropore environments are dominated by advection rather than diffusion. The various driving forces must be analyzed to determine the individual and combined magnitudes of their effects on a specific reef pore-water system. Pore-water movement controls sediment diagenesis, the exchange of nutrients between sediments and benthos, and coastal/island groundwater resources. Because of the complexity of forcing functions, their interactions with specific local reef environments, experimental studies require careful incorporation of these considerations into their design and interpretation. 8 refs., 3 figs., 1 tab.

  17. Pore water colloid properties in argillaceous sedimentary rocks.

    PubMed

    Degueldre, Claude; Cloet, Veerle

    2016-11-01

    The focus of this work is to evaluate the colloid nature, concentration and size distribution in the pore water of Opalinus Clay and other sedimentary host rocks identified for a potential radioactive waste repository in Switzerland. Because colloids could not be measured in representative undisturbed porewater of these host rocks, predictive modelling based on data from field and laboratory studies is applied. This approach allowed estimating the nature, concentration and size distributions of the colloids in the pore water of these host rocks. As a result of field campaigns, groundwater colloid concentrations are investigated on the basis of their size distribution quantified experimentally using single particle counting techniques. The colloid properties are estimated considering data gained from analogue hydrogeochemical systems ranging from mylonite features in crystalline fissures to sedimentary formations. The colloid concentrations were analysed as a function of the alkaline and alkaline earth element concentrations. Laboratory batch results on clay colloid generation from compacted pellets in quasi-stagnant water are also reported. Experiments with colloids in batch containers indicate that the size distribution of a colloidal suspension evolves toward a common particle size distribution independently of initial conditions. The final suspension size distribution was found to be a function of the attachment factor of the colloids. Finally, calculations were performed using a novel colloid distribution model based on colloid generation, aggregation and sedimentation rates to predict under in-situ conditions what makes colloid concentrations and size distributions batch- or fracture-size dependent. The data presented so far are compared with the field and laboratory data. The colloid occurrence, stability and mobility have been evaluated for the water of the considered potential host rocks. In the pore water of the considered sedimentary host rocks, the clay

  18. The Water Retention Curves in THF Hydrate-Bearing Sediments - Experimental Measurement and Pore Scale Simulation

    NASA Astrophysics Data System (ADS)

    Mahabadi, N.; Zheng, X.; Dai, S.; Seol, Y.; Zapata, C.; Yun, T.; Jang, J.

    2015-12-01

    The water retention curve (WRC) of hydrate-bearing sediments is critically important to understand the behaviour of hydrate dissociation for gas production. Most gas hydrates in marine environment have been formed from an aqueous phase (gas-dissolved water). However, the gas hydrate formation from an aqueous phase in a laboratory requires long period due to low gas solubility in water and is also associated with many experimental difficulties such as hydrate dissolution, difficult hydrate saturation control, and dynamic hydrate dissolution and formation. In this study, tetrahydrofuran (THF) is chosen to form THF hydrate because the formation process is faster than gas hydrate formation and hydrate saturation is easy to control. THF hydrate is formed at water-excess condition. Therefore, there is only water in the pore space after a target THF hydrate saturation is obtained. The pore habit of THF hydrate is investigated by visual observation in a transparent micromodel and X-ray computed tomography images; and the water retention curves are obtained under different THF hydrate saturation conditions. Targeted THF hydrate saturations are Sh=0, 0.2, 0.4, 0.6 and 0.8. Results shown that at a given water saturation the capillary pressure increases as THF hydrate saturation increases. And the gas entry pressure increases with increasing hydrate saturation. The WRC obtained by experiments is also compared with the results of a pore-network model simulation and Lattice Boltzmann Method. The fitting parameters of van Genuchten equation for different hydrate saturation conditions are suggested for the use as input parameters of reservoir simulators.

  19. Elucidating the controls on the Mg isotopic composition of marine pore fluids

    NASA Astrophysics Data System (ADS)

    Chanda, P.; Fantle, M.

    2013-12-01

    The Sr and Mg isotopic composition of pore fluids and carbonates from the Neogene section of Ocean Drilling Project Site 806B are reported (87Sr/86Sr and δ26Mg, measured using a Thermo Scientific Neptune Plus multi-collector ICP-MS). Site 806B, located on the northern margin of the Ontong Java Plateau, hosts a thick (776 m cored, depth to basement ~ 1200 m), relatively continuous, carbonate-rich section (between 83 and 96% CaCO3). Our goal in the current study is to use the Sr and Mg isotope data of pore fluids and carbonates to address open questions regarding (1) the extent to which the pore fluid chemistry is overprinted by calcite recrystallization, (2) the effects of diagenesis on bulk carbonate chemistry, and (3) the likelihood of preserving secular seawater δ26Mg trends in pore fluids. Accordingly, the current study compares and contrasts the isotopic and elemental data between adjacent ODP Sites 806B and 807A, which have similar depositional histories, carbonate contents, and pore fluid chemistries. The measured 87Sr/86Sr ratios of pore fluids at 806B range smoothly from 0.70914 at 4.45 mbsf to 0.70851 at 509.3 mbsf, similar (though offset relative) to the bulk carbonate trend (0.70918 to 0.70877 between 1.11 and 501.94 mbsf). The δ26MgDSM3 of 806B pore fluids generally increases from -0.86‰ at 4.45 mbsf to -0.17‰ at 679.0 mbsf. The overall trend is consistent with previously collected δ26Mg data at 807A [1]; there is, however, a significant difference in pore fluid δ26Mg between the two sites at depths of 300 to 600 mbsf. At these depths, 806B pore fluid δ26Mg values are +0.2 to 0.3‰ relative to 807A at similar depths [1]. The application of a depositional reactive transport model to the Sr isotope data suggests that bulk carbonate recrystallization rates at 806B are similar to those at 807A (<2%/Ma) [2]. An iterative model construct is employed to evaluate the dominant controls on the δ26Mg of marine pore fluids; specifically the relative

  20. Advection within shallow pore waters of a coastal lagoon, Florida

    USGS Publications Warehouse

    Cable, J.E.; Martin, Jonathan B.; Swarzenski, Peter W.; Lindenberg, Mary K.; Steward, Joel

    2004-01-01

    Ground water sources can be a significant portion of a local water budget in estuarine environments, particularly in areas with high recharge rates, transmissive aquifers, and permeable marine sediments. However, field measurements of ground water discharge are often incongruent with ground water flow modeling results, leaving many scientists unsure which estimates are accurate. In this study, we find that both measurements and model results are reasonable. The difference between estimates apparently results from the sources of water being measured and not the techniques themselves. In two locations in the Indian River Lagoon estuarine system, we found seepage meter rates similar to rates calculated from the geochemical tracers 222Rn and 226Ra. Ground water discharge rates ranged from 4 to 9 cm/d using seepage meters and 3 to 20 cm/d using 222Rn and 226Ra. In contrast, in comparisons to other studies where finite element ground water flow modeling was used, much lower ground water discharge rates of ∼0.05 to 0.15 cm/d were estimated. These low rates probably represent discharge of meteoric ground water from land-recharged aquifers, while the much higher rates measured with seepage meters, 222Rn, and 226Ra likely include an additional source of surface waters that regularly flush shallow (< 1 m depth) sediments. This resultant total flow of mixed land-recharged water and recirculated surface waters contributes to the total biogeochemical loading in this shallow estuarine environment.

  1. A new collector for in situ pore water sampling in wetland sediment.

    PubMed

    Gao, Feng; Deng, Jiancai; Li, Qinqin; Hu, Liuming; Zhu, Jinge; Hang, Hongjuan; Hu, Weiping

    2012-01-01

    Currently available pore water samplers generally do not allow continuous monitoring of temporal variations in pore water composition. Therefore, a new type of pore water collector was designed and constructed. These collectors were constructed of polyvinyl chloride (PVC) materials, including PVC tubing with one end sealed and another end topped with a removable PVC screw-cap. A row of holes was drilled 10 cm from the sealed end of each collector. These new collectors were deployed in different layers of the sediment in a constructed wetland in Lake Taihu, China, to reveal variations in the nutrient composition of pore water with high spatial and temporal resolution. Specifically, the collectors were driven into the sediment, and the pore water flowed into the tubing via gravity. The pore water was then sampled from the PVC tubing using a portable vacuum pump, and then was taken to the lab within 20 min for analysis of the dissolved oxygen (DO) and nutrient concentration. The DO concentration of the pore water was below the detection limit for all samples, indicating that the pore water was probably not influenced by the air and that the water in the collector tube was representative of the pore water. These findings suggest that the collector is capable of measuring the temporal and spatial variations in the nutrient concentrations in pore water. Furthermore, the inexpensive material, ease of construction, minimal disturbance to the sediment and applicability for wetland sediments are advantages of the collector presented here compared with traditional pore water sampling techniques.

  2. Pore Water PAH Transport in Amended Sediment Caps

    NASA Astrophysics Data System (ADS)

    Gidley, P. T.; Kwon, S.; Ghosh, U.

    2009-05-01

    Capping is a common remediation strategy for contaminated sediments that creates a physical barrier between contaminated sediments and the water column. Diffusive flux of contaminants through a sediment cap is small. However, under certain hydrodynamic conditions such as groundwater potential and tidal pumping, groundwater advection can accelerate contaminant transport. Hydrophobic organic contaminants such as polycyclic aromatic hydrocarbons (PAHs) could be transported through the cap under advective conditions. To better understand PAH migration under these conditions, physical models of sediment caps were evaluated in the laboratory through direct measurement of pore water using solid phase micro-extraction with gas chromatography and mass spectrometry. Contaminated sediment and capping material was obtained from an existing Superfund site that was capped at Eagle Harbor, Washington. A PAH dissolution model linked to an advection-dispersion equation with retardation using published organic carbon-water partitioning coefficients (Koc) was compared to measured PAHs in the sediment and cap porewater of the physical model.

  3. Processes in the pore waters of peat deposits

    SciTech Connect

    Levshenko, T.V.; Efremova, A.G.; Galkina, Z.M.; Surkova, T.E.; Tolstov, K.A.

    1983-01-01

    The composition of the waters of modern peat bogs that have developed in the intracontinental regions under the conditions of bogs of the high-moor, mixed, and lowmoor types have been investigated for the case of a number of peat deposits of the Smolensk, Volgorad, and Pskov provinces. During the work the pH of the deposits and the C1-, Alk, SO/sup 2/-, Ca/sup 2 +/, Mg/sup 2 +/, K- contents of the pore water of modern peat beds were studied. The thickness of the deposits studied amounted to 5-7 m. Samples were taken every 0.5 m in depth. The water was separated from the deposits by pressing out.

  4. Mechanics of water pore formation in lipid membrane under electric field

    NASA Astrophysics Data System (ADS)

    Bu, Bing; Li, Dechang; Diao, Jiajie; Ji, Baohua

    2017-02-01

    Transmembrane water pores are crucial for substance transport through cell membranes via membrane fusion, such as in neural communication. However, the molecular mechanism of water pore formation is not clear. In this study, we apply all-atom molecular dynamics and bias-exchange metadynamics simulations to study the process of water pore formation under an electric field. We show that water molecules can enter a membrane under an electric field and form a water pore of a few nanometers in diameter. These water molecules disturb the interactions between lipid head groups and the ordered arrangement of lipids. Following the movement of water molecules, the lipid head groups are rotated and driven into the hydrophobic region of the membrane. The reorientated lipid head groups inside the membrane form a hydrophilic surface of the water pore. This study reveals the atomic details of how an electric field influences the movement of water molecules and lipid head groups, resulting in water pore formation.

  5. Methods for pore water extraction from unsaturated zone tuff, Yucca Mountain, Nevada

    USGS Publications Warehouse

    Scofield, K.M.

    2006-01-01

    Assessing the performance of the proposed high-level radioactive waste repository at Yucca Mountain, Nevada, requires an understanding of the chemistry of the water that moves through the host rock. The uniaxial compression method used to extract pore water from samples of tuffaceous borehole core was successful only for nonwelded tuff. An ultracentrifugation method was adopted to extract pore water from samples of the densely welded tuff of the proposed repository horizon. Tests were performed using both methods to determine the efficiency of pore water extraction and the potential effects on pore water chemistry. Test results indicate that uniaxial compression is most efficient for extracting pore water from nonwelded tuff, while ultracentrifugation is more successful in extracting pore water from densely welded tuff. Pore water splits collected from a single nonwelded tuff core during uniaxial compression tests have shown changes in pore water chemistry with increasing pressure for calcium, chloride, sulfate, and nitrate. Pore water samples collected from the intermediate pressure ranges should prevent the influence of re-dissolved, evaporative salts and the addition of ion-deficient water from clays and zeolites. Chemistry of pore water splits from welded and nonwelded tuffs using ultracentrifugation indicates that there is no substantial fractionation of solutes.

  6. Effects of a nearshore wastewater discharge: Water column and sediment pore water toxicity

    SciTech Connect

    Krause, P.R.; Carr, R.S.

    1995-12-31

    The relationship between water column and sediment pore water toxicity was investigated near a municipal-industrial wastewater discharge in southern Texas. Toxicity associated with effluent distributions in the water column are known to vary in both time and space. Toxicity of sediment, however, is often more stable over time. Sediment can serve as a long-term integrator of toxicity in areas subject to chronic exposure of effluents. This study addressed the relationship between water column toxicity and that found in the sediments on both spatial and temporal scales. Four 2 Km transacts were established around a nearshore wastewater outfall. Eight stations along each transact were sampled for both surface waters and sediment pore water toxicity. Toxicity was determined using a modified sea urchin fertilization test. Surface waters were sampled and tested for eight consecutive months, while sediment pore waters were sampled on three occasions over the length of this study. Results have shown that toxicity in receiving waters was a good indicator to trace movements of the highly variable effluent plume. The distribution of effluent in the water column, and hence water column toxicity, was primarily driven by local wind conditions. Toxicity in sediment porewater was, much less variable and more evenly distributed over the study site. Sediment pore water toxicity was also a good predictor of the distribution of benthic infaunal invertebrates over much of the study site.

  7. The mineral dissolution rate conundrum: Insights from reactive transport modeling of U isotopes and pore fluid chemistry in marine sediments

    NASA Astrophysics Data System (ADS)

    Maher, Kate; Steefel, Carl I.; DePaolo, Donald J.; Viani, Brian E.

    2006-01-01

    Pore water chemistry and 234U/ 238U activity ratios from fine-grained sediment cored by the Ocean Drilling Project at Site 984 in the North Atlantic were used as constraints in modeling in situ rates of plagioclase dissolution with the multicomponent reactive transport code Crunch. The reactive transport model includes a solid-solution formulation to enable the use of the 234U/ 238U activity ratios in the solid and fluid as a tracer of mineral dissolution. The isotopic profiles are combined with profiles of the major element chemistry (especially alkalinity and calcium) to determine whether the apparent discrepancy between laboratory and field dissolution rates still exists when a mechanistic reactive transport model is used to interpret rates in a natural system. A suite of reactions, including sulfate reduction and methane production, anaerobic methane oxidation, CaCO 3 precipitation, dissolution of plagioclase, and precipitation of secondary clay minerals, along with diffusive transport and fluid and solid burial, control the pore fluid chemistry in Site 984 sediments. The surface area of plagioclase in intimate contact with the pore fluid is estimated to be 6.9 m 2/g based on both grain geometry and on the depletion of 234U/ 238U in the sediment via α-recoil loss. Various rate laws for plagioclase dissolution are considered in the modeling, including those based on (1) a linear transition state theory (TST) model, (2) a nonlinear dependence on the undersaturation of the pore water with respect to plagioclase, and (3) the effect of inhibition by dissolved aluminum. The major element and isotopic methods predict similar dissolution rate constants if additional lowering of the pore water 234U/ 238U activity ratio is attributed to isotopic exchange via recrystallization of marine calcite, which makes up about 10-20% of the Site 984 sediment. The calculated dissolution rate for plagioclase corresponds to a rate constant that is about 10 2 to 10 5 times smaller than

  8. Transient streaming potentials under varying pore-water ionic strength

    NASA Astrophysics Data System (ADS)

    Malama, B.

    2014-12-01

    Streaming potentials (SP) are generated when polar fluids such as groundwater flow through porous media that have charged mineral surfaces. This is due to the flow-shearing of the diffuse layer of the electric double layer (EDL), which is known to form in the fluid phase at the fluid-rock interface. Previous works have suggested that the EDL vanishes at high pore-fluid ionic strengths resulting in vanishing SP signals. However, recent observations in sea-water intrusion applications by Jackson and coworkers indicate that measurable SP signals are obtainable in flows of fluids with high ionic strengths through silica sand. We demonstrate the repeatability of these observations through a series of laboratory flow experiments performed on 98% silica sand in a falling-head permeameter with brines of concentrations ranging from 0.001M to about 5 M NaCl. The results of the experiments, which clearly show measurable SP signals even at the highest concentration of 5 M NaCl, are reported. They are also used to estimate the hydraulic conductivity and electrokinetic coupling coefficient. The linearity assumption for the relation between pressure and SP differentials is evaluated for high pore-water NaCl concentrations. Additionally, displacement of one brine by another of different NaCl concentration yields dramatic transient SP responses that may be harnessed in the development of early-detection/warning technologies for sea-water intrusion applications. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. This research is funded by WIPP programs administered by the Office of Environmental Management (EM) of the U.S Department of Energy.

  9. Organic geochemistry and pore water chemistry of sediments from Mangrove Lake, Bermuda

    USGS Publications Warehouse

    Hatcher, P.G.; Simoneit, B.R.T.; MacKenzie, F.T.; Neumann, A.C.; Thorstenson, D.C.; Gerchakov, S.M.

    1982-01-01

    Mangrove Lake, Bermuda, is a small coastal, brackish-water lake that has accumulated 14 m of banded, gelatinous, sapropelic sediments in less than 104 yr. Stratigraphic evidence indicates that Mangrove Lake's sedimentary environment has undergone three major depositional changes (peat, freshwater gel, brackish-water gel) as a result of sea level changes. The deposits were examined geochemically in an effort to delineate sedimentological and diagenetic changes. Gas and pore water studies include measurements of sulfides, ammonia, methane, nitrogen gas, calcium, magnesium, chloride, alkalinity, and pH. Results indicate that sulfate reduction is complete, and some evidence is presented for bacterial denitrification and metal sulfide precipitation. The organic-rich sapropel is predominantly algal in origin, composed mostly of carbohydrates and insoluble macromolecular organic matter called humin with minor amounts of proteins, lipids, and humic acids. Carbohydrates and proteins undergo hydrolysis with depth in the marine sapropel but tend to be preserved in the freshwater sapropel. The humin, which has a predominantly aliphatic structure, increases linearly with depth and composes the greatest fraction of the organic matter. Humic acids are minor components and are more like polysaccharides than typical marine humic acids. Fatty acid distributions reveal that the lipids are of an algal and/or terrestrial plant source. Normal alkanes with a total concentration of 75 ppm exhibit two distribution maxima. One is centered about n-C22 with no odd/even predominance, suggestive of a degraded algal source. The other is centered at n-C31 with a distinct odd/even predominance indicative of a vascular plant origin. Stratigraphic changes in the sediment correlate to observed changes in the gas and pore water chemistry and the organic geochemistry. ?? 1982.

  10. Toxicity of ammonia in pore-water and in the water column to freshwater benthic invertebrates

    SciTech Connect

    Whiteman, F.W.; Kahl, M.D.; Rau, D.M.; Balcer, M.D.; Ankley, G.T.

    1994-12-31

    Ammonia has been mentioned as both a primary toxicant and a factor that can produce false positive results in laboratory sediment tests using benthic invertebrates. This study developed a sediment dosing system that percolates an ammonia solution through sediment to achieve target porewater ammonia concentrations that remain stable over four and ten day spiked sediment tests. Ten day flow-through water-only tests and ten day spiked sediment tests were used to determine the toxicity of ammonia in the water column and in the sediment pore-water to the oligochaete Lumbriculus variegatus and the midge Chironomus tentans. Four-day tests were run with the amphipod Hyalella azteca. The relationship between water column ammonia toxicity and sediment pore-water ammonia toxicity is influenced by the organism`s association with the sediment. For Lumbriculus variegatus and Chironomus tentans that burrow into the sediment and are in direct contact with the porewater, the pore-water LC50 for ammonia is 30--40% higher than the water-only LC50 for each species. Hyalella azteca is epibenthic and avoids ammonia spiked sediment, thus ammonia in the water column is considerably more toxic than the pore-water ammonia with the porewater LC50 about 800% higher than the water only LC50.

  11. Effects of handling, temperature and storage time on sediment and pore-water chemistry and toxicity

    SciTech Connect

    Lasier, P.J.; Winger, P.V.; Jackson, B.P.

    1994-12-31

    Effects of sediment disturbance, storage temperature (230 C and 40 C) and storage time on chemistry and toxicity of sediment and pore water were evaluated using two sediments (sandy freshwater and organic estuarine) contaminated with metals. Solid-phase (10 d with water renewal) and pore-water (96-h static) toxicity tests with Hyalella azteca were conducted upon collection and at two week intervals for 8--10 weeks. Chemistries (redox, pH, conductivity, alkalinity, ammonia, trace metals, major cations and anions) were measured at each toxicity testing interval. Following extraction, pore-water chemistry changed significantly during the initial 96 h due to oxidation reactions and CO{sub 2} equilibration. Pore water collected in situ was slightly less toxic and had major differences in water chemistry compared to pore water extracted from homogenized sediment. Storage temperature and time significantly influenced pore-water toxicity and chemistry, but had minimal effect on solid-phase toxicity. After four weeks, the highly-toxic sandy sediment became slightly less toxic in solid-phase tests and Significantly less toxic in pore-water tests, coinciding with changes in trace-metal concentrations, activities, and speciation. The estuarine sediment became slightly more toxic in both solid-phase and pore-water tests after four weeks, but returned to original levels after six and eight weeks. Sediment disturbance, storage temperature, and storage time significantly influenced toxicity and pore-water chemistry.

  12. Clinically-Compatible MRI Strategies for Discriminating Bound and Pore Water in Cortical Bone

    PubMed Central

    Horch, R. Adam; Gochberg, Daniel F.; Nyman, Jeffry S.; Does, Mark D.

    2012-01-01

    Advances in modern MRI pulse sequences have enabled clinically-practical cortical bone imaging. Human cortical bone is known to contain a distribution of T1 and T2 components attributed to bound and pore water, although clinical imaging approaches have yet to discriminate bound from pore water on the basis of their relaxation properties. Herein, two clinically-compatible MRI strategies are proposed for selectively imaging either bound or pore water by utilizing differences in their T1s and T2s. The strategies are validated in a population of ex vivo human cortical bones, and estimates obtained for bound and pore water are compared to bone mechanical properties. Results show that the two MRI strategies provide good estimates of bound and pore water that correlate to bone mechanical properties. As such, the strategies for bound and pore water-discrimination shown herein should provide diagnostically useful tools for assessing bone fracture risk, once applied to clinical MRI. PMID:22294340

  13. Influence of Water Table Depth on Pore Water Chemistry and Trihalomethane Formation Potential in Peatlands.

    PubMed

    Gough, Rachel; Holliman, Peter J; Fenner, Nathalie; Peacock, Mike; Freeman, Christopher

    2016-02-01

    Drained peatland catchments are reported to produce more colored, dissolved organic carbon (DOC)-rich water, presenting problems for potable water treatment. The blocking of peatland drainage ditches to restore the water table is increasingly being considered as a strategy to address this deterioration in water quality. However, the effect of ditch blocking on the potential of DOC to form trihalomethanes (THMs) has not been assessed. In this study, the effect of peat rewetting on pore water DOC concentration and characteristics (including THM formation potential [THMFP]) was assessed over 12 months using peat cores collected from two drained peatland sites. The data show little evidence of differences in DOC concentration or characteristics between the different treatments. The absence of any difference in the THMFP of pore water between treatments suggests that, in the short term at least, ditch blocking may not have an effect on the THMFP of waters draining peatland catchments.

  14. Sediment toxicity of a rapidly biodegrading nonionic surfactant: Comparing the equilibrium partitioning approach with measurements in pore water.

    PubMed

    Droge, Steven T J; Postma, Jaap F; Hermens, Joop L M

    2008-06-01

    The equilibrium partitioning theory (EqP) assumes that the toxicity of nonionic surfactants in sediment can be predicted from water-only toxicity data as long as the effect concentrations are properly normalized for chemical activity. Therefore, in marine sediment toxicity tests with the model alcohol ethoxylate (AE), C12EO8, freely dissolved concentrations were both measured via solid-phase microextraction and predicted using sorption coefficients. In fully equilibrated test systems (including the overlying water), both methods showed that concentrations in the pore water of the spiked sediment layer causing 50% mortality (LC50) to the amphipod Corophium volutator were in the same range as LC50 values for amphipods exposed to AE in seawater only. In the sediment systems, AE concentrations in the pore water remained constant up to 15 days, while concentrations in the water overlying the sediment decreased to less than 1% of initial concentrations within 6 days due to biodegradation. In such disequilibrated test systems, C. volutator survived pore water dissolved concentrations that were above the LC50. Apparently, this burrowing amphipod is able to exploit the low chemical activity in the overlying water as a refuge from sediment exposure.

  15. Linking basin-scale and pore-scale gas hydrate distribution patterns in diffusion-dominated marine hydrate systems

    NASA Astrophysics Data System (ADS)

    Nole, Michael; Daigle, Hugh; Cook, Ann E.; Hillman, Jess I. T.; Malinverno, Alberto

    2017-02-01

    The goal of this study is to computationally determine the potential distribution patterns of diffusion-driven methane hydrate accumulations in coarse-grained marine sediments. Diffusion of dissolved methane in marine gas hydrate systems has been proposed as a potential transport mechanism through which large concentrations of hydrate can preferentially accumulate in coarse-grained sediments over geologic time. Using one-dimensional compositional reservoir simulations, we examine hydrate distribution patterns at the scale of individual sand layers (1-20 m thick) that are deposited between microbially active fine-grained material buried through the gas hydrate stability zone (GHSZ). We then extrapolate to two-dimensional and basin-scale three-dimensional simulations, where we model dipping sands and multilayered systems. We find that properties of a sand layer including pore size distribution, layer thickness, dip, and proximity to other layers in multilayered systems all exert control on diffusive methane fluxes toward and within a sand, which in turn impact the distribution of hydrate throughout a sand unit. In all of these simulations, we incorporate data on physical properties and sand layer geometries from the Terrebonne Basin gas hydrate system in the Gulf of Mexico. We demonstrate that diffusion can generate high hydrate saturations (upward of 90%) at the edges of thin sands at shallow depths within the GHSZ, but that it is ineffective at producing high hydrate saturations throughout thick (greater than 10 m) sands buried deep within the GHSZ. Furthermore, we find that hydrate in fine-grained material can preserve high hydrate saturations in nearby thin sands with burial.Plain Language SummaryThis study combines one-, two-, and three-dimensional simulations to explore one potential process by which methane dissolved in <span class="hlt">water</span> beneath the seafloor can be converted into solid methane hydrate. This work specifically</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/653994','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/653994"><span>The one-dimensional compression method for extraction of <span class="hlt">pore</span> <span class="hlt">water</span> from unsaturated tuff and effects on <span class="hlt">pore-water</span> chemistry</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Higgins, J.D.; Burger, P.A.; Yang, L.C.</p> <p>1997-12-31</p> <p>Study of the hydrologic system at Yucca Mountain, Nevada, requires extraction of <span class="hlt">pore-water</span> samples from unsaturated tuff bedrock. Two generations of compression cells have been designed and tested for extracting representative, unaltered <span class="hlt">pore-water</span> samples from unsaturated tuff cores. The one-dimensional compression cell has a maximum compressive stress rating of 552 MPa. Results from 86 tests show that the minimum degree of saturation for successful extraction of <span class="hlt">pore</span> <span class="hlt">water</span> was about 14% for non welded tuff and about 61% for densely welded tuff. The high-pressure, one-dimensional compression cell has a maximum compressive stress rating of 827 MPa. Results from 109 tests show that the minimum degree of saturation for successful extraction of <span class="hlt">pore</span> <span class="hlt">water</span> was about 7.5% for non welded tuff and about 34% for densely welded tuff. Geochemical analyses show that, in general, there is a decrease in ion concentration of <span class="hlt">pore</span> <span class="hlt">waters</span> as extraction pressures increase. Only small changes in <span class="hlt">pore-water</span> composition occur during the one-dimensional extraction test.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19366586','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19366586"><span>Extrusion of transmitter, <span class="hlt">water</span> and ions generates forces to close fusion <span class="hlt">pore</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tajparast, M; Glavinović, M I</p> <p>2009-05-01</p> <p>During exocytosis the fusion <span class="hlt">pore</span> opens rapidly, then dilates gradually, and may subsequently close completely, but what controls its dynamics is not well understood. In this study we focus our attention on forces acting on the <span class="hlt">pore</span> wall, and which are generated solely by the passage of transmitter, ions and <span class="hlt">water</span> through the open fusion <span class="hlt">pore</span>. The transport through the charged cylindrical nano-size <span class="hlt">pore</span> is simulated using a coupled system of Poisson-Nernst-Planck and Navier-Stokes equations and the forces that act radially on the wall of the fusion <span class="hlt">pore</span> are then estimated. Four forces are considered: a) inertial force, b) pressure, c) viscotic force, and d) electrostatic force. The inertial and viscotic forces are small, but the electrostatic force and the pressure are typically significant. High vesicular pressure tends to open the fusion <span class="hlt">pore</span>, but the pressure induced by the transport of charged particles (glutamate, ions), which is predominant when the <span class="hlt">pore</span> wall charge density is high tends to close the <span class="hlt">pore</span>. The electrostatic force, which also depends on the charge density on the <span class="hlt">pore</span> wall, is weakly repulsive before the <span class="hlt">pore</span> dilates, but becomes attractive and pronounced as the <span class="hlt">pore</span> dilates. Given that the vesicular concentration of free transmitter can change rapidly due to the release, or owing to the dissociation from the gel matrix, we evaluated how much and how rapidly a change of the vesicular K(+)-glutamate(-) concentration affects the concentration of glutamate(-) and ions in the <span class="hlt">pore</span> and how such changes alter the radial force on the wall of the fusion <span class="hlt">pore</span>. A step-like rise of the vesicular K(+)-glutamate(-) concentration leads to a chain of events. <span class="hlt">Pore</span> concentration (and efflux) of both K(+) and glutamate(-) rise reaching their new steady-state values in less than 100 ns. Interestingly within a similar time interval the <span class="hlt">pore</span> concentration of Na(+) also rises, whereas that of Cl(-) diminishes, although their extra-cellular concentration does not</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70021540','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70021540"><span>Dissolved sulfide distributions in the <span class="hlt">water</span> column and sediment <span class="hlt">pore</span> <span class="hlt">waters</span> of the Santa Barbara Basin</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Kuwabara, J.S.; VanGeen, A.; McCorkle, D.C.; Bernhard, J.M.</p> <p>1999-01-01</p> <p>Dissolved sulfide concentrations in the <span class="hlt">water</span> column and in sediment <span class="hlt">pore</span> <span class="hlt">waters</span> were measured by square-wave voltammetry (nanomolar detection limit) during three cruises to the Santa Barbara Basin in February 1995, November-December 1995, and April 1997. In the <span class="hlt">water</span> column, sulfide concentrations measured outside the basin averaged 3 ?? 1 nM (n = 28) in the 0 to 600 m depth range. Inside the basin, dissolved sulfides increased to reach values of up to 15 nM at depths >400 m. A suite of box cores and multicores collected at four sites along the northeastern flank of the basin showed considerable range in surficial (400 ??M at 10 cm. Decreases in <span class="hlt">water</span>-column nitrate below the sill depth indicate nitrate consumption (-55 to -137 ??mole m-2 h-1) similar to nearby Santa Monica Basin. Peaks in <span class="hlt">pore-water</span> iron concentrations were generally observed between 2 and 5 cm depth with shallowest peaks at the 590 m site. These observations, including observations of the benthic microfauna, suggest that the extent to which the sulfide flux, sustained by elevated <span class="hlt">pore-water</span> concentrations, reaches the <span class="hlt">water</span> column may be modulated by the abundance of sulfide-oxidizing bacteria in addition to iron redox and precipitation reactions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title40-vol26/pdf/CFR-2012-title40-vol26-sec227-31.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title40-vol26/pdf/CFR-2012-title40-vol26-sec227-31.pdf"><span>40 CFR 227.31 - Applicable <span class="hlt">marine</span> <span class="hlt">water</span> quality criteria.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-07-01</p> <p>... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Applicable <span class="hlt">marine</span> <span class="hlt">water</span> quality... § 227.31 Applicable <span class="hlt">marine</span> <span class="hlt">water</span> quality criteria. Applicable <span class="hlt">marine</span> <span class="hlt">water</span> quality criteria means the criteria given for <span class="hlt">marine</span> <span class="hlt">waters</span> in the EPA publication “Quality Criteria for Water” as published in...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title40-vol24/pdf/CFR-2010-title40-vol24-sec227-31.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title40-vol24/pdf/CFR-2010-title40-vol24-sec227-31.pdf"><span>40 CFR 227.31 - Applicable <span class="hlt">marine</span> <span class="hlt">water</span> quality criteria.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-07-01</p> <p>... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Applicable <span class="hlt">marine</span> <span class="hlt">water</span> quality... § 227.31 Applicable <span class="hlt">marine</span> <span class="hlt">water</span> quality criteria. Applicable <span class="hlt">marine</span> <span class="hlt">water</span> quality criteria means the criteria given for <span class="hlt">marine</span> <span class="hlt">waters</span> in the EPA publication “Quality Criteria for Water” as published in...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_3 --> <div id="page_4" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="61"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title40-vol26/pdf/CFR-2013-title40-vol26-sec227-31.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title40-vol26/pdf/CFR-2013-title40-vol26-sec227-31.pdf"><span>40 CFR 227.31 - Applicable <span class="hlt">marine</span> <span class="hlt">water</span> quality criteria.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-07-01</p> <p>... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Applicable <span class="hlt">marine</span> <span class="hlt">water</span> quality... § 227.31 Applicable <span class="hlt">marine</span> <span class="hlt">water</span> quality criteria. Applicable <span class="hlt">marine</span> <span class="hlt">water</span> quality criteria means the criteria given for <span class="hlt">marine</span> <span class="hlt">waters</span> in the EPA publication “Quality Criteria for Water” as published in...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title40-vol25/pdf/CFR-2014-title40-vol25-sec227-31.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title40-vol25/pdf/CFR-2014-title40-vol25-sec227-31.pdf"><span>40 CFR 227.31 - Applicable <span class="hlt">marine</span> <span class="hlt">water</span> quality criteria.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-07-01</p> <p>... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Applicable <span class="hlt">marine</span> <span class="hlt">water</span> quality... § 227.31 Applicable <span class="hlt">marine</span> <span class="hlt">water</span> quality criteria. Applicable <span class="hlt">marine</span> <span class="hlt">water</span> quality criteria means the criteria given for <span class="hlt">marine</span> <span class="hlt">waters</span> in the EPA publication “Quality Criteria for Water” as published in...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title40-vol25/pdf/CFR-2011-title40-vol25-sec227-31.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title40-vol25/pdf/CFR-2011-title40-vol25-sec227-31.pdf"><span>40 CFR 227.31 - Applicable <span class="hlt">marine</span> <span class="hlt">water</span> quality criteria.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-07-01</p> <p>... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Applicable <span class="hlt">marine</span> <span class="hlt">water</span> quality... § 227.31 Applicable <span class="hlt">marine</span> <span class="hlt">water</span> quality criteria. Applicable <span class="hlt">marine</span> <span class="hlt">water</span> quality criteria means the criteria given for <span class="hlt">marine</span> <span class="hlt">waters</span> in the EPA publication “Quality Criteria for Water” as published in...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70032871','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70032871"><span>Bottom sediments and <span class="hlt">pore</span> <span class="hlt">waters</span> near a hydrothermal vent in Lake Baikal (Frolikha Bay)</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Granina, L.Z.; Klerkx, J.; Callender, E.; Leermakers, M.; Golobokova, L.P.</p> <p>2007-01-01</p> <p>We discuss the redox environments and the compositions of bottom sediments and sedimentary <span class="hlt">pore</span> <span class="hlt">waters</span> in the region of a hydrothermal vent in Frolikha Bay, Lake Baikal. According to our results, the submarine vent and its companion nearby spring on land originate from a common source. The most convincing evidence for their relation comes from the proximity of stable oxygen and hydrogen isotope compositions in <span class="hlt">pore</span> <span class="hlt">waters</span> and in the spring <span class="hlt">water</span>. The isotope composition indicates a meteoric origin of <span class="hlt">pore</span> <span class="hlt">waters</span>, but their major- and minor-element chemistry bears imprint of deep <span class="hlt">water</span> which may seep through permeable faulted crust. Although <span class="hlt">pore</span> <span class="hlt">waters</span> near the submarine vent have a specific enrichment in major and minor constituents, hydrothermal discharge at the Baikal bottom causes a minor impact on the lake <span class="hlt">water</span> chemistry, unlike the case of freshwater geothermal lakes in the East-African Rift and North America. ?? 2007.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28365504','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28365504"><span>Metal(loid) speciation and size fractionation in sediment <span class="hlt">pore</span> <span class="hlt">water</span> depth profiles examined with a new meso profiling system.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schroeder, Henning; Fabricius, Anne-Lena; Ecker, Dennis; Ternes, Thomas A; Duester, Lars</p> <p>2017-03-23</p> <p>In an exemplary incubation study with an anaerobic sediment sampled at an oxbow of the river Lahn in Germany (50°18'56.87″N; 7°37'41.25″E) and contaminated by former mining activity, a novel meso profiling and sampling system (messy) is presented. Messy enables a low invasive, automated sampling of <span class="hlt">pore</span> <span class="hlt">water</span> profiles across the sediment <span class="hlt">water</span> interface (SWI), down to ∼20 cm depth with a spacial resolution of 1 cm. In parallel to the <span class="hlt">pore</span> <span class="hlt">water</span> sampling it measures physicochemical sediment parameters such as redox potential and pH value. In an incubation experiment of 151 days the ability of the setup was proven to address several different aspects relevant for fresh <span class="hlt">water</span> and <span class="hlt">marine</span> sediment studies: (i) The influence of mechanical disturbance and oxygen induced acidification on the mobility of 13 metals and metalloids (Cd, Co, Cu, Fe, Mn, Mo, Ni, Sb, U, V, Zn) was quantified based on 11 profiles. The analytes were quantified by inductively coupled plasma-mass spectrometry. Three groups of elements were identified with respect to the release into the <span class="hlt">pore</span> <span class="hlt">water</span> and the overlying <span class="hlt">water</span> under different experimental conditions. (ii) The capability to investigate the impacts of changing physicochemical sediment properties on arsenic and antimony (III/V) speciation is shown. (iii) An approach to obtain information on size fractionation effects and to address the colloidal <span class="hlt">pore</span> <span class="hlt">water</span> fractions (0.45 μm-16 μm) was successfully conducted for the elements Ag, As, Cu, Fe and Mn.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6481585','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6481585"><span>Three-phase modeling of polycyclic aromatic hydrocarbon association with <span class="hlt">pore-water</span>-dissolved organic carbon</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mitra, S. ); Dickhut, R.M. )</p> <p>1999-06-01</p> <p>Log-log plots of measured organic carbon-normalized sediment <span class="hlt">pore-water</span> distribution coefficients (K[prime][sub OC]s) for several polycyclic aromatic hydrocarbons (PAHs) versus their octanol-<span class="hlt">water</span> partition coefficients (K[prime][sub OW]s) at two sites in the Elizabeth River, Virginia, show large deviations from linearity. Organic-carbon normalized distribution coefficients for these PAHs between sediments and <span class="hlt">pore</span> <span class="hlt">waters</span> decreased by more than two orders of magnitude with depth as well. To determine to what extent <span class="hlt">pore</span> <span class="hlt">water</span> dissolved and colloidal organic carbon (DOC) was responsible for the observed nonlinearity and decrease in K[prime][sub OC], a three-phase model was used to estimate <span class="hlt">pore-water</span> PAH-DOC binding coefficients (K[sub DOC]). Partitioning of PAHs to <span class="hlt">pore-water</span> DOC (i.e., K[sub DOC])enhances the observed dissolved phase PAH concentration, especially for high-K[sub OW] compounds, contributing to the nonlinearity in K[prime][sub OC]-K[sub OW] plots. However, the application of the three-phase partitioning model to these data indicate that, at most, <span class="hlt">pore-water</span> PAH-DOC binding accounts for one order of magnitude of the observed decrease in K[prime][sub OC] with depth in the sediment bed. The results of this study are consistent with three-phase partitioning theory for hydrophobic organic compounds between sediment organic matter, <span class="hlt">pore-water</span> DOC, and freely dissolved aqueous phases in natural systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26076248','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26076248"><span><span class="hlt">Pore</span>-size dependent THz absorption of nano-confined <span class="hlt">water</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sun, Chi-Kuang; You, Borwen; Huang, Yu-Ru; Liu, Kao-Hsiang; Sato, Shusaku; Irisawa, Akiyoshi; Imamura, Motoki; Mou, Chung-Yuan</p> <p>2015-06-15</p> <p>We performed a THz absorption spectroscopy study on liquid <span class="hlt">water</span> confined in mesoporous silica materials, MCM-41-S-18 and MCM-41-S-21, of two different <span class="hlt">pore</span> sizes at room temperatures. We found that stronger confinement with a smaller <span class="hlt">pore</span> size causes reduced THz absorption, indicating reduced <span class="hlt">water</span> mobility due to confinement. Combined with recent theoretical studies showing that the microscopic structure of <span class="hlt">water</span> inside the nanopores can be separated into a core <span class="hlt">water</span> region and an interfacial <span class="hlt">water</span> region, our spectroscopy analysis further reveals a bulk-<span class="hlt">water</span>-like THz absorption behavior in the core <span class="hlt">water</span> region and a solid-like THz absorption behavior in the interfacial <span class="hlt">water</span> region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/807903','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/807903"><span>Molecular simulation study of <span class="hlt">water</span>--methanol mixtures in activated carbon <span class="hlt">pores</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shevade, Abhijit V.; Jiang, Shaoyi; Gubbins, Keith E.</p> <p>2000-10-22</p> <p>We report a theoretical study of the adsorption behavior of <span class="hlt">water</span>--methanol mixtures in slit activated carbon micropores. The adsorption isotherms are obtained for a <span class="hlt">pore</span> of width 2 nm at a temperature of 298 K from grand canonical ensemble Monte Carlo simulations. The <span class="hlt">water</span> molecules are modeled using the four point transferable intermolecular potential functions (TIP4P) and methanol by the optimized potentials for liquid simulations (OPLS). Carboxyl (COOH) groups are used as active sites on a structured carbon surface. The effect of the relative contributions from dispersion and hydrogen bonding interactions of adsorbates, and of the chemical activation of adsorbents on adsorption behavior is investigated. The adsorption of the mixture components in activated carbon <span class="hlt">pores</span> occurs by continuous filling, without the sharp capillary condensation observed in graphite <span class="hlt">pores</span>. <span class="hlt">Water</span> is preferentially adsorbed over methanol in activated carbon <span class="hlt">pores</span> for a wide range of pressures, except at lower pressures. The hydrophilic nature of activated carbon <span class="hlt">pores</span> results in the complexation of both <span class="hlt">water</span> and methanol molecules with the active sites on the surfaces, leading to bulklike <span class="hlt">water</span> behavior over the entire <span class="hlt">pore</span> width. Solvation forces are also calculated as a function of <span class="hlt">pore</span> size. The negative values found for the solvation force for all <span class="hlt">pore</span> sizes reflect the hydrophilic interactions of the mixtures with the activated carbon surfaces. {copyright} 2000 American Institute of Physics [S0021-9606(00)51339-7</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/7163018','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/7163018"><span>Aqueous-, <span class="hlt">pore-water</span>-, and sediment-phase cadmium: Toxicity relationships for a meiobenthic copepod</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Green, A.S.; Chandler, G.T.; Blood, E.R. . Dept. of Environmental Health Sciences)</p> <p>1993-08-01</p> <p>Comparative effects of aqueous-, <span class="hlt">pore-water</span>-, and sediment-phase cadmium on mortality of an infaunal laboratory-cultured copepod, Amphiascus tenuiremis, were determined using acute 96-h bioassays. Experimental design included five cadmium concentrations, three replicates per concentration, and 50 adult copepods per replicate for each of the exposure. Exposures included cadmium solubilized in seawater only, whole sediment, and <span class="hlt">pore</span> <span class="hlt">water</span> only. In addition, two whole-sediment bioassays were compared in which <span class="hlt">pore-water</span> cadmium concentrations were altered experimentally but sediment concentrations remained the same. Results of these experiments showed that for Amphiascus tenuiremis, cadmium is most toxic in the aqueous phase, less toxic in the <span class="hlt">pore-water</span> phase, and last toxic in the sediment-bound phase. The lowered toxicity of cadmium in the <span class="hlt">pore</span> <span class="hlt">water</span> was most likely due to complexation of cadmium with DOC, because concentrations of DOC were six times higher in the <span class="hlt">pore-water</span> phase than in the aqueous phase. In whole sediments, <span class="hlt">pore-water</span>-phase cadmium was the primary source of acute toxicity, as sediment-associated cadmium contributed negligible effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.springerlink.com/content/x8xwcnu1gux6e4pf/?p=9624ca7895ad465ab98960a32b52bcff&pi=1','USGSPUBS'); return false;" href="http://www.springerlink.com/content/x8xwcnu1gux6e4pf/?p=9624ca7895ad465ab98960a32b52bcff&pi=1"><span>The influence of extraction procedure on ion concentrations in sediment <span class="hlt">pore</span> <span class="hlt">water</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Winger, P.V.; Lasier, P.J.; Jackson, B.P.</p> <p>1998-01-01</p> <p>Sediment <span class="hlt">pore</span> <span class="hlt">water</span> has the potential to yield important information on sediment quality, but the influence of isolation procedures on the chemistry and toxicity are not completely known and consensus on methods used for the isolation from sediment has not been reached. To provide additional insight into the influence of collection procedures on <span class="hlt">pore</span> <span class="hlt">water</span> chemistry, anion (filtered only) and cation concentrations were measured in filtered and unfiltered <span class="hlt">pore</span> <span class="hlt">water</span> isolated from four sediments using three different procedures: dialysis, centrifugation and vacuum. Peepers were constructed using 24-cell culture plates and cellulose membranes, and vacuum extractors consisted of fused-glass air stones attached with airline tubing to 60cc syringes. Centrifugation was accomplished at two speeds (2,500 and 10,000 x g) for 30 min in a refrigerated centrifuge maintained at 4?C. Only minor differences in chemical characteristics and cation and anion concentrations were found among the different collecting methods with differences being sediment specific. Filtering of the <span class="hlt">pore</span> <span class="hlt">water</span> did not appreciably reduce major cation concentrations, but trace metals (Cu and Pb) were markedly reduced. Although the extraction methods evaluated produced <span class="hlt">pore</span> <span class="hlt">waters</span> of similar chemistries, the vacuum extractor provided the following advantages over the other methods: (1) ease of extraction, (2) volumes of <span class="hlt">pore</span> <span class="hlt">water</span> isolated, (3) minimal preparation time and (4) least time required for extraction of <span class="hlt">pore</span> <span class="hlt">water</span> from multiple samples at one time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26897083','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26897083"><span>Behaviour of butyltin compounds in the sediment <span class="hlt">pore</span> <span class="hlt">waters</span> of a contaminated marina (Port Camargue, South of France).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Briant, Nicolas; Bancon-Montigny, Chrystelle; Freydier, Rémi; Delpoux, Sophie; Elbaz-Poulichet, Françoise</p> <p>2016-05-01</p> <p>Despite the ban on tributyltin (TBT) in <span class="hlt">marine</span> paints, harbour sediments are still highly contaminated by this antifouling agent. Concentrations of TBT and its dealkylated products dibutyltin (DBT) and monobutyltin (MBT) were determined in the <span class="hlt">pore</span> <span class="hlt">waters</span> of Port Camargue, a large marina located on the French Mediterranean coast. <span class="hlt">Pore</span> <span class="hlt">waters</span> were sampled in the field using peepers deployed in summer 2012 and 2013 and in winter 2012-2013. The winter surveys were characterized by the presence of sulphides in <span class="hlt">pore</span> <span class="hlt">waters</span> from a depth of 5 cm, which was not the case in winter. In summer 2013, TBT was shown to be released into <span class="hlt">pore</span> <span class="hlt">waters</span> below the sediment-<span class="hlt">water</span> interface (SWI) at concentrations of up to 70 ngSn L(-1). This release was also observed in sediment anaerobic incubations and was attributed to the mineralization of the sedimentary organic matter, possible stabilization of TBT by complexation with sulphides, and lower debutylation rates in anoxic than in oxic conditions. In summer 2012, a comparatively lower concentration of TBT (around 20 ngSn L(-1) below the SWI) was measured and the presence of methyltin species was detected. We hypothesize that the differences between the two surveys reflect different microbial activity. In winter 2012-2013, marked by Fe-reducing conditions in the sediments, TBT was released into solution at the SWI at concentrations of up to 40 ngSn L(-1). Sediments are thus a continuing source of TBT for the overlying <span class="hlt">waters</span> despite the ban on its use for boats in France.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016WRR....52.1729M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016WRR....52.1729M"><span>Relating salt marsh <span class="hlt">pore</span> <span class="hlt">water</span> geochemistry patterns to vegetation zones and hydrologic influences</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moffett, Kevan B.; Gorelick, Steven M.</p> <p>2016-03-01</p> <p>Physical, chemical, and biological factors influence vegetation zonation in salt marshes and other wetlands, but connections among these factors could be better understood. If salt marsh vegetation and marsh <span class="hlt">pore</span> <span class="hlt">water</span> geochemistry coorganize, e.g., via continuous plant <span class="hlt">water</span> uptake and persistently unsaturated sediments controlling vegetation zone-specific <span class="hlt">pore</span> <span class="hlt">water</span> geochemistry, this could complement known physical mechanisms of marsh self-organization. A high-resolution survey of <span class="hlt">pore</span> <span class="hlt">water</span> geochemistry was conducted among five salt marsh vegetation zones at the same intertidal elevation. Sampling transects were arrayed both parallel and perpendicular to tidal channels. <span class="hlt">Pore</span> <span class="hlt">water</span> geochemistry patterns were both horizontally differentiated, corresponding to vegetation zonation, and vertically differentiated, relating to root influences. The geochemical patterns across the site were less broadly related to marsh hydrology than to vegetation zonation. Mechanisms contributing to geochemical differentiation included: root-induced oxidation and nutrient (P) depletion, surface and creek-bank sediment flushing by rainfall or tides, evapotranspiration creating aerated <span class="hlt">pore</span> space for partial sediment flushing in some areas while persistently saturated conditions hindered <span class="hlt">pore</span> <span class="hlt">water</span> renewal in others, and evapoconcentration of <span class="hlt">pore</span> <span class="hlt">water</span> solutes overall. The concentrated <span class="hlt">pore</span> <span class="hlt">waters</span> draining to the tidal creeks accounted for 41% of ebb tide solutes (median of 14 elements), including being a potentially toxic source of Ni but a slight sink for Zn, at least during the short, winter study period in southern San Francisco Bay. Heterogeneous vegetation effects on <span class="hlt">pore</span> <span class="hlt">water</span> geochemistry are not only significant locally within the marsh but may broadly influence marsh-estuary solute exchange and ecology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23116121','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23116121"><span>Size effects of <span class="hlt">pore</span> density and solute size on <span class="hlt">water</span> osmosis through nanoporous membrane.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhao, Kuiwen; Wu, Huiying</p> <p>2012-11-15</p> <p>Understanding the behavior of osmotic transport across nanoporous membranes at molecular level is critical to their design and applications, and it is also beneficial to the comprehension of the mechanism of biological transmembrane transport processes. <span class="hlt">Pore</span> density is an important parameter for nanoporous membranes. To better understand the influence of <span class="hlt">pore</span> density on osmotic transport, we have performed systematic molecular dynamics simulations on <span class="hlt">water</span> osmosis across nanoporous membranes with different <span class="hlt">pore</span> densities (i.e., number of <span class="hlt">pores</span> per unit area of membrane). The simulation results reveal that significant size effects occur when the <span class="hlt">pore</span> density is so high that the center-to-center distance between neighboring nanopores is comparable to the solute size. The size effects are independent of the <span class="hlt">pore</span> diameter and solute concentration. A simple quantitative correlation between <span class="hlt">pore</span> density, solute size, and osmotic flux has been established. The results are excellently consistent with the theoretical predictions. It is also shown that solute hydration plays an important role in real osmotic processes. Solute hydration strengthens the size effects of <span class="hlt">pore</span> density on osmotic processes due to the enlarged effective solute size induced by hydration. The influence of <span class="hlt">pore</span> density, solute size, and solute hydration on <span class="hlt">water</span> osmosis through nanoporous membranes can be introduced to eliminate the deviations of real osmotic processes from ideal behavior.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013CPL...582....1G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013CPL...582....1G"><span>Dynamics of <span class="hlt">water</span> in the amphiphilic <span class="hlt">pore</span> of amyloid β fibrils</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>GhattyVenkataKrishna, Pavan K.; Mostofian, Barmak</p> <p>2013-09-01</p> <p>Alzheimers disease related amyloid peptide, Aβ, forms a fibrillar structure through aggregation. The aggregate is stabilized by a salt bridge that is responsible for the formation of an amphiphilic <span class="hlt">pore</span> that can accommodate <span class="hlt">water</span> molecules. None of the reported structures of Aβ, however, contain <span class="hlt">water</span>. We present results from molecular dynamics simulations on dimeric Aβ fibrils solvated in <span class="hlt">water</span>. <span class="hlt">Water</span> penetrates and fills the amphiphilic <span class="hlt">pore</span> increasing its volume. We observe a thick wire of <span class="hlt">water</span> that is translationally and rotationally stiff in comparison to bulk <span class="hlt">water</span> and may be essential for the stabilization of the amyloid Aβ protein.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.H51C0898I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.H51C0898I"><span>Comparison of <span class="hlt">Pore</span> <span class="hlt">Water</span> Chemical Extracted by Different Forces with In-situ Properties</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ito, N.; Machida, I.; Marui, A.; Scheytt, T.; Hebig, K. H.</p> <p>2010-12-01</p> <p>Due to the difficulty involved for in-situ sampling of groundwater, <span class="hlt">pore</span> <span class="hlt">water</span> was extracted from rock core samples for chemical analysis. Available literature indicated that, the chemical constituents of <span class="hlt">pore</span> <span class="hlt">water</span> are affected by large extraction force. This study is therefore aimed at discussing the reason behind the change in <span class="hlt">pore</span> <span class="hlt">water</span> chemistry when samples are subjected to different extraction forces. The process involved extraction of <span class="hlt">pore</span> <span class="hlt">water</span> from sandstone core samples at different pF values by centrifuge method. The pF expresses the tension of <span class="hlt">water</span>, retained in soil. It is the base 10 logarithm of tension, which is measured as a head of <span class="hlt">water</span> head in centimeters. The samples of lengths 100 m each were obtained from three locations. Tracer test using Iodine was also conducted to remove <span class="hlt">pore</span> <span class="hlt">water</span> polluted by drilling <span class="hlt">water</span>. <span class="hlt">Pore</span> <span class="hlt">water</span> was extracted from a total of 63 samples at three different values of pF (low: up to pF 2.3, medium: pF 2.3 - 3.9, high: pF 3.9 - 4.3). For each pF range the <span class="hlt">pore</span> <span class="hlt">water</span> was analyzed for major anions and cations. Results showed variation of ionic concentrations with pF and depth. The average concentrations rose with increase of pF in all ions except for potassium. Based on the concentration distribution of Ca2+, three zones could be defined: (1) Ca2+ concentration, which does not depend on pF, (2) Ca2+ concentration, which increases with the value of pF and (3) Ca2+ showing the same value for medium and high pF values. It is thus concluded that, <span class="hlt">water</span> chemistry of deep <span class="hlt">pore</span> <span class="hlt">water</span> is likely to have reached equilibrium due to almost stagnant flow conditions, whereas shallow <span class="hlt">water</span> is likely to participate in chemical interactions due to the relatively high flow velocity. The depths of the interfaces of these three zones are almost consistent with geological boundaries of weathered and fine sandstone and there is evidence of a relationship between <span class="hlt">pore</span> <span class="hlt">water</span> chemistry and physical rock properties. Using this knowledge, we</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21570165','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21570165"><span>Field sampling of soil <span class="hlt">pore</span> <span class="hlt">water</span> to evaluate trace element mobility and associated environmental risk.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Moreno-Jiménez, Eduardo; Beesley, Luke; Lepp, Nicholas W; Dickinson, Nicholas M; Hartley, William; Clemente, Rafael</p> <p>2011-10-01</p> <p>Monitoring soil pollution is a key aspect in sustainable management of contaminated land but there is often debate over what should be monitored to assess ecological risk. Soil <span class="hlt">pore</span> <span class="hlt">water</span>, containing the most labile pollutant fraction in soils, can be easily collected in situ offering a routine way to monitor this risk. We present a compilation of data on concentration of trace elements (As, Cd, Cu, Pb, and Zn) in soil <span class="hlt">pore</span> <span class="hlt">water</span> collected in field conditions from a range of polluted and non-polluted soils in Spain and the UK during single and repeated monitoring, and propose a simple eco-toxicity test using this media. Sufficient <span class="hlt">pore</span> <span class="hlt">water</span> could be extracted for analysis both under semi-arid and temperate conditions, and eco-toxicity comparisons could be effectively made between polluted and non-polluted soils. We propose that in-situ <span class="hlt">pore</span> <span class="hlt">water</span> extraction could enhance the realism of risk assessment at some contaminated sites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1063731','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1063731"><span><span class="hlt">Pore-Water</span> Extraction Scale-Up Study for the SX Tank Farm</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Truex, Michael J.; Oostrom, Martinus; Wietsma, Thomas W.; Last, George V.; Lanigan, David C.</p> <p>2013-01-15</p> <p>The phenomena related to <span class="hlt">pore-water</span> extraction from unsaturated sediments have been previously examined with limited laboratory experiments and numerical modeling. However, key scale-up issues have not yet been addressed. Laboratory experiments and numerical modeling were conducted to specifically examine <span class="hlt">pore-water</span> extraction for sediment conditions relevant to the vadose zone beneath the SX Tank Farm at Hanford Site in southeastern Washington State. Available SX Tank Farm data were evaluated to generate a conceptual model of the subsurface for a targeted <span class="hlt">pore-water</span> extraction application in areas with elevated moisture and Tc-99 concentration. The hydraulic properties of the types of porous media representative of the SX Tank Farm target application were determined using sediment mixtures prepared in the laboratory based on available borehole sediment particle size data. Numerical modeling was used as an evaluation tool for scale-up of <span class="hlt">pore-water</span> extraction for targeted field applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/5223368','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/5223368"><span>A vacuum-operated <span class="hlt">pore-water</span> extractor for estuarine and freshwater sediments</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Winger, Parley V.; Lasier, Peter J.</p> <p>1991-01-01</p> <p>A vacuum-operated <span class="hlt">pore-water</span> extractor for estuarine and freshwater sediments was developed and constructed from a fused-glass air stone attached with aquarium airline tubing to a 30 or 60 cc polypropylene syringe. <span class="hlt">Pore</span> <span class="hlt">water</span> is extracted by inserting the air stone into the sediment and creating a vacuum by retracting and bracing the syringe plunger. A hand-operated vacuum pump attached to a filtration flask was also evaluated as an alternative vacuum source. The volume and time to extract <span class="hlt">pore</span> <span class="hlt">water</span> varies with the number of devices and the sediment particle size. Extraction time is longer for fine sediments than for sandy sediments. Four liters of sediment generally yield between 500 and 1,500 mL of <span class="hlt">pore</span> <span class="hlt">water</span>. The sediment that surrounds and accumulates on the air stone acts as a filter, and, except for the first few milliliters, the collected <span class="hlt">pore</span> <span class="hlt">water</span> is clear. Because there is no exposure to air or avenue for escape, volatile compounds andin situ characteristics are retained in the extracted <span class="hlt">pore</span> <span class="hlt">water</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27711832','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27711832"><span>Transformation of chlorpyrifos and chlorpyrifos-methyl in prairie pothole <span class="hlt">pore</span> <span class="hlt">waters</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Adams, Rachel M; McAdams, Brandon C; Arnold, William A; Chin, Yu-Ping</p> <p>2016-11-09</p> <p>Non-point source pesticide pollution is a concern for wetlands in the prairie pothole region (PPR). Recent studies have demonstrated that reduced sulfur species (e.g., bisulfide and polysulfides) in PPR wetland <span class="hlt">pore</span> <span class="hlt">waters</span> directly undergo reactions with chloroacetanilide and dinitroaniline compounds. In this paper, the abiotic transformation of two organophosphate compounds, chlorpyrifos and chlorpyrifos-methyl, was studied in PPR wetland <span class="hlt">pore</span> <span class="hlt">waters</span>. Chlorpyrifos-methyl reacted significantly faster (up to 4 times) in <span class="hlt">pore</span> <span class="hlt">water</span> with reduced sulfur species relative to hydrolysis. No rate enhancement was observed in the transformation of chlorpyrifos in <span class="hlt">pore</span> <span class="hlt">water</span> with reduced sulfur species. The lack of reactivity was most likely caused by steric hindrance from the ethyl groups and partitioning to dissolved organic matter (DOM), thereby shielding chlorpyrifos from nucleophilic attack. Significant decreases in reaction rates were observed for chlorpyrifos in <span class="hlt">pore</span> <span class="hlt">water</span> with high concentrations of DOM. Rate enhancement due to other reactive species (e.g., organo-sulfur compounds) in <span class="hlt">pore</span> <span class="hlt">water</span> was minor for both compounds relative to the influence of bisulfide and DOM.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70014892','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70014892"><span>Dissolved organic matter in anoxic <span class="hlt">pore</span> <span class="hlt">waters</span> from Mangrove Lake, Bermuda</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Orem, W.H.; Hatcher, P.G.; Spiker, E. C.; Szeverenyi, N.M.; Maciel, G.E.</p> <p>1986-01-01</p> <p>Dissolved organic matter and dissolved inorganic chemical species in anoxic <span class="hlt">pore</span> <span class="hlt">water</span> from Mangrove Lake, Bermuda sediments were studied to evaluate the role of <span class="hlt">pore</span> <span class="hlt">water</span> in the early diagenesis of organic matter. Dissolved sulphate, titration alkalinity, phosphate, and ammonia concentration versus depth profiles were typical of many nearshore clastic sediments and indicated sulphate reduction in the upper 100 cm of sediment. The dissolved organic matter in the <span class="hlt">pore</span> <span class="hlt">water</span> was made up predominantly of large molecules, was concentrated from large quantities of <span class="hlt">pore</span> <span class="hlt">water</span> by using ultrafiltration and was extensively tudied by using elemental and stable carbon isotope analysis and high-resolution, solid state 13C nuclear magnetic resonance and infrared spectroscopy. The results indicate that this material has a predominantly polysaccharide-like structure and in addition contains a large amount of oxygen-containing functional groups (e.g., carboxyl groups). The 13C nulcear magnetic resonance spectra of the high-molecular-weight dissolved organic matter resemble those of the organic matter in the surface sediments of Mangrove Lake. We propose that this high-molecular-weight organic matter in <span class="hlt">pore</span> <span class="hlt">waters</span> represents the partially degraded, labile organic components of the sedimentary organic matter and that <span class="hlt">pore</span> <span class="hlt">waters</span> serve as a conduit for removal of these labile organic components from the sediments. The more refractory components are, thus, selectively preserved in the sediments as humic substances (primarily humin). ?? 1986.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_4 --> <div id="page_5" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="81"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1261452','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1261452"><span><span class="hlt">Pore</span>-size dependence and characteristics of <span class="hlt">water</span> diffusion in slitlike micropores</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Diallo, S. O.</p> <p>2015-07-16</p> <p>The temperature dependence of the dynamics of <span class="hlt">water</span> inside microporous activated carbon fibers (ACF) is investigated by means of incoherent elastic and quasielastic neutron-scattering techniques. The aim is to evaluate the effect of increasing <span class="hlt">pore</span> size on the <span class="hlt">water</span> dynamics in these primarily hydrophobic slit-shaped channels. Using two different micropore sizes (similar to 12 and 18 angstrom, denoted, respectively, ACF-10 and ACF-20), a clear suppression of the mobility of the <span class="hlt">water</span> molecules is observed as the <span class="hlt">pore</span> gap or temperature decreases. Suppression, we found, is accompanied by a systematic dependence of the average translational diffusion coefficient D-r and relaxation time [tau(0)] of the restricted <span class="hlt">water</span> on <span class="hlt">pore</span> size and temperature. We observed D-r values and tested against a proposed scaling law, in which the translational diffusion coefficient D-r of <span class="hlt">water</span> within a porous matrix was found to depend solely on two single parameters, a temperature-independent translational diffusion coefficient D-c associated with the <span class="hlt">water</span> bound to the <span class="hlt">pore</span> walls and the ratio theta of this strictly confined <span class="hlt">water</span> to the total <span class="hlt">water</span> inside the <span class="hlt">pore</span>, yielding unique characteristic parameters for <span class="hlt">water</span> transport in these carbon channels across the investigated temperature range.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvE..92a2312D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvE..92a2312D"><span><span class="hlt">Pore</span>-size dependence and characteristics of <span class="hlt">water</span> diffusion in slitlike micropores</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Diallo, S. O.</p> <p>2015-07-01</p> <p>The temperature dependence of the dynamics of <span class="hlt">water</span> inside microporous activated carbon fibers (ACF) is investigated by means of incoherent elastic and quasielastic neutron-scattering techniques. The aim is to evaluate the effect of increasing <span class="hlt">pore</span> size on the <span class="hlt">water</span> dynamics in these primarily hydrophobic slit-shaped channels. Using two different micropore sizes (˜12 and 18 Å, denoted, respectively, ACF-10 and ACF-20), a clear suppression of the mobility of the <span class="hlt">water</span> molecules is observed as the <span class="hlt">pore</span> gap or temperature decreases. This suppression is accompanied by a systematic dependence of the average translational diffusion coefficient Dr and relaxation time <τ0> of the restricted <span class="hlt">water</span> on <span class="hlt">pore</span> size and temperature. The observed Dr values are tested against a proposed scaling law, in which the translational diffusion coefficient Dr of <span class="hlt">water</span> within a porous matrix was found to depend solely on two single parameters, a temperature-independent translational diffusion coefficient Dc associated with the <span class="hlt">water</span> bound to the <span class="hlt">pore</span> walls and the ratio θ of this strictly confined <span class="hlt">water</span> to the total <span class="hlt">water</span> inside the <span class="hlt">pore</span>, yielding unique characteristic parameters for <span class="hlt">water</span> transport in these carbon channels across the investigated temperature range.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1261452-pore-size-dependence-characteristics-water-diffusion-slitlike-micropores','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1261452-pore-size-dependence-characteristics-water-diffusion-slitlike-micropores"><span><span class="hlt">Pore</span>-size dependence and characteristics of <span class="hlt">water</span> diffusion in slitlike micropores</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Diallo, S. O.</p> <p>2015-07-16</p> <p>The temperature dependence of the dynamics of <span class="hlt">water</span> inside microporous activated carbon fibers (ACF) is investigated by means of incoherent elastic and quasielastic neutron-scattering techniques. The aim is to evaluate the effect of increasing <span class="hlt">pore</span> size on the <span class="hlt">water</span> dynamics in these primarily hydrophobic slit-shaped channels. Using two different micropore sizes (similar to 12 and 18 angstrom, denoted, respectively, ACF-10 and ACF-20), a clear suppression of the mobility of the <span class="hlt">water</span> molecules is observed as the <span class="hlt">pore</span> gap or temperature decreases. Suppression, we found, is accompanied by a systematic dependence of the average translational diffusion coefficient D-r and relaxation timemore » [tau(0)] of the restricted <span class="hlt">water</span> on <span class="hlt">pore</span> size and temperature. We observed D-r values and tested against a proposed scaling law, in which the translational diffusion coefficient D-r of <span class="hlt">water</span> within a porous matrix was found to depend solely on two single parameters, a temperature-independent translational diffusion coefficient D-c associated with the <span class="hlt">water</span> bound to the <span class="hlt">pore</span> walls and the ratio theta of this strictly confined <span class="hlt">water</span> to the total <span class="hlt">water</span> inside the <span class="hlt">pore</span>, yielding unique characteristic parameters for <span class="hlt">water</span> transport in these carbon channels across the investigated temperature range.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26527298','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26527298"><span>Evaluation of bound and <span class="hlt">pore</span> <span class="hlt">water</span> in cortical bone using ultrashort-TE MRI.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Jun; Grogan, Shawn P; Shao, Hongda; D'Lima, Darryl; Bydder, Graeme M; Wu, Zhihong; Du, Jiang</p> <p>2015-12-01</p> <p>Bone <span class="hlt">water</span> exists in different states with the majority bound to the organic matrix and to mineral, and a smaller fraction in 'free' form in the <span class="hlt">pores</span> of cortical bone. In this study, we aimed to develop and evaluate ultrashort-TE (UTE) MRI techniques for the assessment of T2*, T1 and concentration of collagen-bound and <span class="hlt">pore</span> <span class="hlt">water</span> in cortical bone using a 3-T clinical whole-body scanner. UTE MRI, together with an isotope study using tritiated and distilled <span class="hlt">water</span> (THO-H2O) exchange, as well as gravimetric analysis, were performed on ten sectioned bovine bone samples. In addition, 32 human cortical bone samples were prepared for comparison between the <span class="hlt">pore</span> <span class="hlt">water</span> concentration measured with UTE MRI and the cortical porosity derived from micro-computed tomography (μCT). A short T2* of 0.27 ± 0.03 ms and T1 of 116 ± 6 ms were observed for collagen-bound <span class="hlt">water</span> in bovine bone. A longer T2* of 1.84 ± 0.52 ms and T1 of 527 ± 28 ms were observed for <span class="hlt">pore</span> <span class="hlt">water</span> in bovine bone. UTE MRI measurements showed a <span class="hlt">pore</span> <span class="hlt">water</span> concentration of 4.7-5.3% by volume and collagen-bound <span class="hlt">water</span> concentration of 15.7-17.9% in bovine bone. THO-H2O exchange studies showed a <span class="hlt">pore</span> <span class="hlt">water</span> concentration of 5.9 ± 0.6% and collagen-bound <span class="hlt">water</span> concentration of 18.1 ± 2.1% in bovine bone. Gravimetric analysis showed a <span class="hlt">pore</span> <span class="hlt">water</span> concentration of 6.3 ± 0.8% and collagen-bound <span class="hlt">water</span> concentration of 19.2 ± 3.6% in bovine bone. A mineral <span class="hlt">water</span> concentration of 9.5 ± 0.6% was derived in bovine bone with the THO-H2O exchange study. UTE-measured <span class="hlt">pore</span> <span class="hlt">water</span> concentration is highly correlated (R(2) = 0.72, p < 0.0001) with μCT porosity in the human cortical bone study. Both bovine and human bone studies suggest that UTE sequences could reliably measure collagen-bound and <span class="hlt">pore</span> <span class="hlt">water</span> concentration in cortical bone using a clinical scanner.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6881071','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6881071"><span>Eutrophication in the northern Adriatic Sea: <span class="hlt">Pore</span> <span class="hlt">water</span> and sediment studies</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hammond, D.E.; Berelson, W.M. ); Giordani, P.; Langone, L.; Frignani, M.; Ravaioli, M. )</p> <p>1990-01-09</p> <p>The northern Adriatic Sea has been plagued by problems of eutrophication. This area is relatively shallow (maximum depth = 60m), becoming stratified during the summer months which inhibits oxygen transport to bottom <span class="hlt">waters</span>. Anthropogenic nutrient loading in rivers entering the northern Adriatic (Po River being the largest) has increased nutrient input to this system and stimulated algal growth. Cores were collected for studies of <span class="hlt">pore</span> <span class="hlt">water</span> and solid phase chemistry at 6 stations in this region. [sup 210]Pb was used to constrain sediment accumulation rates and a range of 0-0.5 cm/yr was determined at different stations. Excess [sup 234]Th was only found in the upper 1-2 cm, suggesting that bioturbation is largely restricted to shallow depths. <span class="hlt">Pore</span> <span class="hlt">water</span> profiles show evidence of irrigation, and mean diffusive fluxes for oxygen, silica phosphate and ammonia are generally 20-90% of the fluxes obtained from benthic chamber measurements. This is consistent with previous work in this area in which studies of radon fluxes indicated that irrigation plays an important role in sediment-<span class="hlt">water</span> exchange. <span class="hlt">Pore</span> <span class="hlt">water</span> profiles in the northern portion of the study area (near the Po River Delta) were markedly different than profiles in the south; sediments in the north are substantially more acidic and have high concentrations of dissolved iron and phosphate. From the alkalinity vs. TCO[sub 2] relationship in sediment <span class="hlt">pore</span> <span class="hlt">waters</span> it appears that differences in reactions involving the reduction of iron oxides and the exchange of magnesium for iron in clays are responsible for this regional difference in <span class="hlt">pore</span> <span class="hlt">water</span> properties. Sediments close to the Po apparently undergo more iron-magnesium exchange, while more distal sediments are limited in their ability to do so. Other <span class="hlt">pore</span> <span class="hlt">water</span> observations are limited in their ability to do so. Other <span class="hlt">pore</span> <span class="hlt">water</span> observations and trends regarding the shape of the silica profiles (which show shallow maxima) will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24814907','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24814907"><span>Mechanisms of <span class="hlt">water</span> interaction with <span class="hlt">pore</span> systems of hydrochar and pyrochar from poplar forestry waste.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Conte, Pellegrino; Hanke, Ulrich M; Marsala, Valentina; Cimò, Giulia; Alonzo, Giuseppe; Glaser, Bruno</p> <p>2014-05-28</p> <p>The aim of this study was to understand the <span class="hlt">water</span>-surface interactions of two chars obtained by gasification (pyrochar) and hydrothermal carbonization (hydrochar) of a poplar biomass. The two samples revealed different chemical compositions as evidenced by solid state (13)C NMR spectroscopy. In fact, hydrochar resulted in a lignin-like material still containing oxygenated functionalities. Pyrochar was a polyaromatic system in which no heteronuclei were detected. After saturation with <span class="hlt">water</span>, hydrochar and pyrochar were analyzed by fast field cycling (FFC) NMR relaxometry. Results showed that <span class="hlt">water</span> movement in hydrochar was mainly confined in very small <span class="hlt">pores</span>. Conversely, <span class="hlt">water</span> movement in pyrochar led to the conclusion that a larger number of transitional and very large <span class="hlt">pores</span> were present. These results were confirmed by porosity evaluation derived from gas adsorption. Variable-temperature FFC NMR experiments confirmed a slow-motion regime due to a preferential diffusion of <span class="hlt">water</span> on the solid surface. Conversely, the higher number of large <span class="hlt">pores</span> in pyrochar allowed slow movement only up to 50 °C. As the temperature was raised to 80 °C, <span class="hlt">water</span> interactions with the <span class="hlt">pore</span> surface became weaker, thereby allowing a three-dimensional <span class="hlt">water</span> exchange with the bulk liquid. This paper has shown that <span class="hlt">pore</span> size distribution was more important than chemical composition in affecting <span class="hlt">water</span> movement in two chemically different charred systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5533797','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5533797"><span>Inorganic and organic sulfur cycling in salt-marsh <span class="hlt">pore</span> <span class="hlt">waters</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Luther, G.W. III; Church, T.M.; Scudlark, J.R.; Cosman, M.</p> <p>1986-05-09</p> <p>Sulfur species in <span class="hlt">pore</span> <span class="hlt">waters</span> of the Great Marsh, Delaware, were analyzed seasonally by polarographic methods. The species determined (and their concentrations in micromoles per liter) included inorganic sulfides (less than or equal to3360), polysulfides (less than or equal to326), thiosulfate (less than or equal to104), tetrathionate (less than or equal to302), organic thiols (less than or equal to2411), and organic disulfides (less than or equal to139). Anticipated were bisulfide increases with depth due to sulfate reduction and subsurface sulfate excesses and pH minima, the result of a seasonal redox cycle. Unanticipated was the pervasive presence of thiols (for example, glutathione), particularly during periods of biological production. Salt marshes appear to be unique among <span class="hlt">marine</span> systems in producing high concentrations of thiols. Polysulfides, thiosulfate, and tetrathionate also exhibited seasonal subsurface maxima. These results suggest a dynamic seasonal cycling of sulfur in salt marshes involving abiological and biological reactions and dissolved and solid sulfur species. The chemosynthetic turnover of pyrite to organic sulfur is a likely pathway for this sulfur cycling. Thus, material, chemical, and energy cycles in wetlands appear to be optimally synergistic.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26799222','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26799222"><span>Adsorption of As(V) inside the <span class="hlt">pores</span> of porous hematite in <span class="hlt">water</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dai, Min; Xia, Ling; Song, Shaoxian; Peng, Changsheng; Lopez-Valdivieso, Alejandro</p> <p>2016-04-15</p> <p>As(V) adsorption inside the <span class="hlt">pores</span> of porous hematite in <span class="hlt">water</span> has been studied in this work. This study was performed on nonporous hematite and porous hematite prepared from the thermal decomposition of goethite and siderite through the measurements of adsorption isotherm, SEM-EDX, XRD and BET. The results demonstrated that the As(V) adsorption was difficult to be realized inside <span class="hlt">pores</span> if they were too small. This observation might be due to that the <span class="hlt">pore</span> entrances were blocked by the adsorbed ions and thus the inside surfaces became invalid for the adsorption. Only if the <span class="hlt">pore</span> size is large enough, the effective surface area inside <span class="hlt">pores</span> would be close to that on non-porous hematite for As(V) adsorption. In addition, it was found that siderite is better than goethite for preparing porous hematite with thermal decomposition as adsorbent for arsenic removal.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18767050','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18767050"><span>Laser scanning confocal microscopy characterization of <span class="hlt">water</span> repellent distribution in a sandstone <span class="hlt">pore</span> network.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zoghlami, Karima; Gómez-Gras, David; Corbella, Mercè; Darragi, Fadila</p> <p>2008-11-01</p> <p>In the present work, we propose the use of the Laser Scanning Confocal Microscopy (LSCM) to determine the effect of <span class="hlt">water</span> repellents on rock's <span class="hlt">pore</span>-network configuration and interconnection. The rocks studied are sandstones of Miocene age, a building material that is commonly found in the architectural heritage of Tunisia. The porosity quantitative data of treated and untreated samples, obtained by mercury porosimetry tests, were compared. The results show a slight decrease in total porosity with the <span class="hlt">water</span> repellent treatment, which reduced both microporosity and macroporosity. This reduction produced a modification in <span class="hlt">pore</span> size distribution and a shift of the <span class="hlt">pore</span> access size mode interval toward smaller <span class="hlt">pore</span> diameters (from the 30-40 microm to the 20-30 microm intervals). The <span class="hlt">water</span> repellent was observed in SEM images as a continuous film coating grain surfaces; moreover, it was easily visualized in LSCM, by staining the <span class="hlt">water</span> repellent with Epodye fluorochrome, and the coating thickness was straightforwardly measured (1.5-2 microm). In fact, the combination of mercury intrusion porosimetry data and LSCM observations suggests that the porosity reduction and the shift of the <span class="hlt">pore</span> diameter mode were mainly due to the general reduction of <span class="hlt">pore</span> diameters, but also to the plugging of the smallest <span class="hlt">pores</span> (less than 3-4 microm in diameter) by the <span class="hlt">water</span> repellent film. Finally, the LSCM technique enabled the reconstruction of 3D views of the <span class="hlt">water</span> repellent coating film in the <span class="hlt">pore</span> network, indicating that its distribution was uniform and continuous over the 100 microm thick sample. The LSCM imaging facilitates the integration and interpretation of mercury porosimetry and SEM data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70028771','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70028771"><span>Uranium distribution in the coastal <span class="hlt">waters</span> and <span class="hlt">pore</span> <span class="hlt">waters</span> of Tampa Bay, Florida</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Swarzenski, P.W.; Baskaran, M.</p> <p>2006-01-01</p> <p>The geochemical reactivity of uranium (238U) and dissolved organic carbon (DOC), Fe, Mn, Ba, and V was investigated in the <span class="hlt">water</span> column, <span class="hlt">pore</span> <span class="hlt">waters</span>, and across a river/estuarine mixing zone in Tampa Bay, Florida. This large estuary is impacted both by diverse anthropogenic activity and by extensive U-rich phosphatic deposits. Thus, the estuarine behavior of uranium may be examined relative to such known U enrichments and anthropogenic perturbations. Dissolved (< 0.45??m) uranium exhibited both removal and enrichment processes across the Alafia River/estuarine mixing zone relative to conservative mixing. Such non-conservative U behavior may be attributed to: i) physical mixing processes within the river; ii) U carrier phase reactivity; and/or iii) fluid exchange processes across sediment/<span class="hlt">water</span> interface. In the bay proper, U concentrations were ?????2 to 3 times greater than those reported for other estuarine systems and are likely a result of erosional inputs from the extensive, underlying U-rich phosphatic deposits. Whereas dissolved U concentrations generally did not approach seawater values (13.6??nM) along the Alafia River salinity transect, <span class="hlt">water</span> column U concentrations exceeded 16??nM in select regions of the bay. Within the hydrogeological framework of the bay, such enriched U may also be derived from advective fluid transport processes across the sediment/<span class="hlt">water</span> interface, such as submarine groundwater discharge (SGD) or hyporheic exchange within coastal rivers. <span class="hlt">Pore</span> <span class="hlt">water</span> profiles of U in Tampa Bay show both a flux into and out of bottom sediments, and average, diffusive U <span class="hlt">pore</span> <span class="hlt">water</span> fluxes (Jdiff) ranged from - 82.0 to 116.6??mol d- 1. It is likely that negative U fluxes imply seawater entrainment or infiltration (i.e., submarine groundwater recharge), which may contribute to the removal of <span class="hlt">water</span> column uranium. For comparison, a bay-wide, Ra-derived submarine groundwater discharge estimate for Tampa Bay (8??L m- 2 d- 1) yielded an average, advective</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/458312','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/458312"><span>Bioavailability of trace contaminants ({sup 241}Am, {sup 57}Co, {sup 137}Cs) to a benthic bivalve from <span class="hlt">pore</span> <span class="hlt">waters</span> and sediments</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gagnon, C.; Stupakoff, I.; Fisher, N.S.</p> <p>1995-12-31</p> <p>Sediments are major repositories of contaminants in <span class="hlt">marine</span> ecosystems and can serve as a source of some contaminants for benthic organisms. The authors used the clam Macoma balthica, a species employed in monitoring coastal contamination, to compare experimentally three uptake sources: overlying <span class="hlt">water</span>, ingested surface sediment and anoxic <span class="hlt">pore</span> <span class="hlt">water</span>. They studied the bioavailability of selected radionuclides ({sup 241}Am, {sup 57}Co, {sup 137}Cs) representing a large range of particle reactivity. For comparison, the authors also used CH{sub 3} {sup 203}Hg, which is highly assimilated by <span class="hlt">marine</span> organisms. Clams were exposed separately to contaminated overlying <span class="hlt">water</span>, surface oxic sediment and anoxic sediment. Radioactivity in animals was determined at the end of the exposure period. {sup 137}CS, which is not particle reactive in seawater, was not bioaccumulated from any source. {sup 241}Am and {sup 57}Co concentration factors in clams obtained from overlying <span class="hlt">water</span> were approximately an order of magnitude lower than that of CH{sub 3} {sup 203}Hg. Ingested oxidized sediment particles do not appear to be a significant source for these radionuclides. {sup 241}Am, {sup 57}Co and CH{sub 3} {sup 203}Hg were bioconcentrated from anoxic <span class="hlt">pore</span> <span class="hlt">waters</span>, but the highly particle-reactive {sup 241}Am was mostly adsorbed onto the clam`s shell. The bioconcentration of CH{sub 3} {sup 203}Hg from <span class="hlt">pore</span> <span class="hlt">waters</span> was, however, only one tenth of that from overlying <span class="hlt">water</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9341E..0GC','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9341E..0GC"><span>Analysis of quasi-periodic <span class="hlt">pore</span>-network structure of centric <span class="hlt">marine</span> diatom frustules</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cohoon, Gregory A.; Alvarez, Christine E.; Meyers, Keith; Deheyn, Dimitri D.; Hildebrand, Mark; Kieu, Khanh; Norwood, Robert A.</p> <p>2015-03-01</p> <p>Diatoms are a common type of phytoplankton characterized by their silica exoskeleton known as a frustule. The diatom frustule is composed of two valves and a series of connecting girdle bands. Each diatom species has a unique frustule shape and valves in particular species display an intricate pattern of <span class="hlt">pores</span> resembling a photonic crystal structure. We used several numerical techniques to analyze the periodic and quasi-periodic valve <span class="hlt">pore</span>-network structure in diatoms of the Coscinodiscophyceae order. We quantitatively identify defect locations and <span class="hlt">pore</span> spacing in the valve and use this information to better understand the optical and biological properties of the diatom.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70014414','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70014414"><span>The representativeness of <span class="hlt">pore</span> <span class="hlt">water</span> samples collected from the unsaturated zone using pressure-vacuum lysimeters</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Peters, C.A.; Healy, R.W.</p> <p>1988-01-01</p> <p>Studies have indicated that the chemistry of <span class="hlt">water</span> samples may be altered by the collection technique, creating concern about the representativeness of the <span class="hlt">pore</span> <span class="hlt">water</span> samples obtained. A study using soil <span class="hlt">water</span> pressure-vacuum lysimeters in outwash sand and glacial till deposits demonstrates that for non-dilute-solution samples the effect of pH of sampling with lysimeters is minimal, and that measured major cation and anion concentrations are representative of the natural <span class="hlt">pore</span> <span class="hlt">water</span>; trace-metal concentrations can be significantly altered by collection procedures at low concentrations. -from Authors</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.H43A1433S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.H43A1433S"><span>Influences of Salinity Variations on <span class="hlt">Pore-water</span> Flow in Salt Marshes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shen, C.; Jin, G.; Xin, P.; Li, L.</p> <p>2013-12-01</p> <p>Salt marshes are important wetlands at the ocean-land interface with various ecological functions, serving as essential habitats for intertidal fauna, affecting the productivity of coastal <span class="hlt">waters</span> through nutrient exchange, moderating the greenhouse gas emission and global warming. They are influenced by various physical and biogeochemical processes, among which the <span class="hlt">pore-water</span> flow and associated solute transport processes play an important role in determining the material exchange between marsh soils and coastal <span class="hlt">water</span>. Previous studies have examined such processes under the solo or combined effects of tidal fluctuation, evapotranspiration, stratigraphy, inland freshwater input, and topography. However, these investigations have neglected the spatial and temporal salinity variations in surface <span class="hlt">water</span> and <span class="hlt">pore-water</span>, which commonly exist in salt marshes due to the impacts of tidal inundation, precipitation and evapotranspiration. The density contrast between the surface <span class="hlt">water</span> and <span class="hlt">pore-water</span> may lead to significant modifications of the <span class="hlt">pore-water</span> flow. Based on results from laboratory experiments and numerical simulations, we will demonstrate that: (1) under upward salinity gradients, flow instabilities in the form of fingers occur once the salinity contrast reaches a certain level, whereas under downward salinity gradients the system is stable; (2) because of the strong tidally-induced advective process occurring near the creek, both the number and size of fingers change gradually from the near-creek zone to the marsh interior; and (3) both upward and downward salinity gradients enhance the exchange between the surface <span class="hlt">water</span> and <span class="hlt">pore-water</span> in the marsh sediments. Keywords: Salt marshes; density effect; salinity gradient; <span class="hlt">pore-water</span> flow; fingers. Instabilities under upward salinity gradient Stable system under downward salinity gradient</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1981Natur.290..243T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1981Natur.290..243T"><span>Methylmercury production in the <span class="hlt">marine</span> <span class="hlt">water</span> column</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Topping, G.; Davies, I. M.</p> <p>1981-03-01</p> <p>Although the biosynthesis of methylmercury in sediments is well established1, this is not necessarily the exclusive natural source of methylmercury entering the <span class="hlt">marine</span> food chain, particularly commercial fish and shellfish species for human consumption. An examination of mercury levels in freshwater fish2, collected from a lake with a history of industrial mercury contamination, suggested that levels in fish are controlled in part by mercury in suspension and it followed that methylation should occur in the <span class="hlt">water</span> column. Although methylmercury is present in seawater in coastal areas receiving discharges of waste containing either inorganic mercury3 or methylmercury4 there is no evidence that methylmercury is actually formed in the <span class="hlt">water</span> column. We now present data which demonstrate that inorganic mercury can be methylated in the <span class="hlt">water</span> column and we compare this production with that known to occur in <span class="hlt">marine</span> sediments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SuTMP...5a4003C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SuTMP...5a4003C"><span>A kinetic study of the spontaneous penetration of a <span class="hlt">water</span> drop into a hydrophobic <span class="hlt">pore</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Choi, Hyunho; Ma, Lian; Liang, Hong</p> <p>2017-03-01</p> <p>The spontaneous penetration of a <span class="hlt">water</span> drop into hydrophobic single-<span class="hlt">pored</span> samples of varying inside and outside diameters was studied. During penetration, the radius of the <span class="hlt">water</span> drop, its contact angle, the contact radius, and the penetration length inside the <span class="hlt">pore</span> were measured against time. Experimental results showed that a <span class="hlt">water</span> drop on the sample with the smaller <span class="hlt">pore</span> had a longer penetration time than a <span class="hlt">water</span> drop on the sample with the bigger <span class="hlt">pore</span>. A <span class="hlt">pored</span> sample with a small outside radius (thin tube) leads to a fast penetration rate presenting a parabolic trend in penetration versus time. The maximum penetration rate was observed when the contact angle was 90°. This is mainly due to the minimum radius of the drop at this angle as the drop radius directly relates to the Laplace pressure, which is the driving force in penetration. Two factors were identified as affecting penetration. The first is the receding contact angle leading to the stick-slip-like motion of a <span class="hlt">water</span> drop. The second is the outside radius of a <span class="hlt">pored</span> sample, which affects the penetration rate and trend. These factors were also correlated to the penetration process through theoretical analysis considering the geometry of the capillary system, volume conservation and momentum conservation. The initial contact angle and radius of a drop were determined by the outside radius of a <span class="hlt">pored</span> sample, which changed Laplace pressure with time, thus influencing the penetration trend and rate. This indicates that a thin tube promotes fast penetration, and the point of maximum penetration rate was shown to be later during the penetration. Understanding the effects of outside radius and receding contact angle in the kinetic aspect of drop penetration into a hydrophobic <span class="hlt">pore</span> is fundamentally important. This research is beneficial to the design of porous materials and in controlling the wetting and penetration process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014GeoRL..41.4176D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GeoRL..41.4176D"><span><span class="hlt">Water</span> permeability in hydrate-bearing sediments: A <span class="hlt">pore</span>-scale study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dai, Sheng; Seol, Yongkoo</p> <p>2014-06-01</p> <p>Permeability is a critical parameter governing methane flux and fluid flow in hydrate-bearing sediments; however, limited valid data are available due to experimental challenges. Here we investigate the relationship between apparent <span class="hlt">water</span> permeability (k') and hydrate saturation (Sh), accounting for hydrate <span class="hlt">pore</span>-scale growth habit and meso-scale heterogeneity. Results from capillary tube models rely on cross-sectional tube shapes and hydrate <span class="hlt">pore</span> habits, thus are appropriate only for sediments with uniform hydrate distribution and known hydrate <span class="hlt">pore</span> character. Given our <span class="hlt">pore</span> network modeling results showing that accumulating hydrate in sediments decreases sediment porosity and increases hydraulic tortuosity, we propose a modified Kozeny-Carman model to characterize <span class="hlt">water</span> permeability in hydrate-bearing sediments. This model agrees well with experimental results and can be easily implemented in reservoir simulators with no empirical variables other than Sh. Results are also relevant to flow through other natural sediments that undergo diagenesis, salt precipitation, or bio-clogging.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1029434','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1029434"><span><span class="hlt">Pore-Water</span> Extraction Intermediate-Scale Laboratory Experiments and Numerical Simulations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Oostrom, Martinus; Freedman, Vicky L.; Wietsma, Thomas W.; Truex, Michael J.</p> <p>2011-06-30</p> <p>A series of flow cell experiments was conducted to demonstrate the process of <span class="hlt">water</span> removal through <span class="hlt">pore-water</span> extraction in unsaturated systems. In this process, a vacuum (negative pressure) is applied at the extraction well establishing gas and <span class="hlt">water</span> pressure gradients towards the well. The gradient may force <span class="hlt">water</span> and dissolved contaminants, such as 99Tc, to move towards the well. The tested flow cell configurations consist of packings, with or without fine-grained well pack material, representing, in terms of particle size distribution, subsurface sediments at the SX tank farm. A <span class="hlt">pore</span> <span class="hlt">water</span> extraction process should not be considered to be equal to soil vapor extraction because during soil vapor extraction, the main goal may be to maximize gas removal. For <span class="hlt">pore</span> <span class="hlt">water</span> extraction systems, pressure gradients in both the gas and <span class="hlt">water</span> phases need to be considered while for soil vapor extraction purposes, gas phase flow is the only concern. In general, based on the limited set (six) of flow experiments that were conducted, it can be concluded that <span class="hlt">pore</span> <span class="hlt">water</span> extraction rates and cumulative outflow are related to <span class="hlt">water</span> content, the applied vacuum, and the dimensions of the sediment layer providing the extracted <span class="hlt">water</span>. In particular, it was observed that application of a 100-cm vacuum (negative pressure) in a controlled manner leads to <span class="hlt">pore-water</span> extraction until the <span class="hlt">water</span> pressure gradients towards the well approach zero. Increased cumulative outflow was obtained with an increase in initial <span class="hlt">water</span> content from 0.11 to 0.18, an increase in the applied vacuum to 200 cm, and when the <span class="hlt">water</span>-supplying sediment was not limited. The experimental matrix was not sufficiently large to come to conclusions regarding maximizing cumulative outflow.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H31G1510Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H31G1510Z"><span>Dynamics of <span class="hlt">pore-water</span> and salt in estuarine marshes subjected to tide and evaporation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, C.; Shen, C.; Li, L.; Lockington, D. A.</p> <p>2015-12-01</p> <p>Salt dynamics in estuarine tidal marshes are strongly associated with their intrinsic hydrological processes and ecological behaviors, which are not well understood. Numerical simulations were carried out to investigate the transport and distribution of <span class="hlt">pore</span> <span class="hlt">water</span> and salt in a vertical cross section perpendicular to the tidal creek that subjects to spring-neap tide and evaporation. Vaporizing <span class="hlt">pore</span> <span class="hlt">water</span> from unsaturated soil surface with salt left in soils, the time-variant actual evaporation is affected by aerodynamic factors as well as soil conditions, including <span class="hlt">pore-water</span> saturation, solute concentration and the thickness of salt precipitation above the soil surface (efflorescence). Different simulation cases were performed by adjusting the tidal signal, marsh platform slope and soil properties. The simulation analysis indicates that, the tide-averaged soil salinity increases with the reduction of inundation period in a spring-neap tide cycle. As the salt accumulated by evaporation could leave soil from seepage back to seawater during ebbtide, the <span class="hlt">pore-water</span> salinity at the surface within the tidal range remains close to that of seawater. With the presence of hyper-saline soil and efflorescence, salt flat develops only in the area where capillary connection between evaporating surface and <span class="hlt">water</span>-saturated soil is maintained while tidal inundation absent. On the contrary, the sandy supratidal marsh where hydrological connections are disrupted keeps a relatively low soil salinity (40-60 ppt) and <span class="hlt">pore-water</span> saturation as evaporation remains low throughout the tidal cycles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002GeCoA..66.1311R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002GeCoA..66.1311R"><span>Solute transport in formations of very low permeability: profiles of stable isotope and dissolved noble gas contents of <span class="hlt">pore</span> <span class="hlt">water</span> in the Opalinus Clay, Mont Terri, Switzerland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rübel, André P.; Sonntag, Christian; Lippmann, Johanna; Pearson, F. J.; Gautschi, Andreas</p> <p>2002-04-01</p> <p><span class="hlt">Pore</span> <span class="hlt">water</span> profiles of <span class="hlt">water</span>, stable isotope, and dissolved noble gas content have been determined across the Opalinus Clay and adjacent formations at the rock laboratory at Mont Terri. We have found enhanced helium contents (up to [ 4He] = 1 × 10 -4 cubic centimeters at standard pressure and temperature per gram of <span class="hlt">pore</span> <span class="hlt">water</span>) and argon isotope ratios ( 40Ar/ 36Ar ratios up to 334) due to accumulation of 4He and 40Ar produced in situ. The helium profile was found to be in steady state with respect to in situ production and diffusive loss into the adjacent limestones where groundwater circulates. From this profile a representative mean value of the apparent diffusion coefficient for helium in the <span class="hlt">pore</span> <span class="hlt">water</span> of the whole formation was derived for the first time to be D a = 3.5 × 10 -11 m 2 · s -1, which is more than two orders of magnitude lower than the diffusion coefficient D 0 in free <span class="hlt">water</span>. The stable isotope profile, however, indicates a component of fossil <span class="hlt">marine</span> <span class="hlt">pore</span> <span class="hlt">water</span>, which has not yet been replaced by molecular diffusion of meteoric <span class="hlt">water</span> from the adjacent limestone and shale formations over the past 10 million years.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_5 --> <div id="page_6" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="101"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20821486','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20821486"><span>Evaluation of hexavalent chromium in sediment <span class="hlt">pore</span> <span class="hlt">water</span> of the Hackensack River, New Jersey, USA.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Driscoll, Susan Kane; McArdle, Margaret E; Plumlee, Megan H; Proctor, Deborah</p> <p>2010-03-01</p> <p><span class="hlt">Pore</span> <span class="hlt">water</span> was collected from in situ passive samplers in Hackensack River sediments adjacent to a chromite ore processing residue site in Kearny, New Jersey. Although the sediments at this site contained more than 3,000 mg/kg of total chromium (Cr) and shallow groundwater adjacent to the shore contained more than 1,000 microg/L of hexavalent Cr [Cr(VI)], concentrations of dissolved total Cr and Cr(VI) in <span class="hlt">pore</span> <span class="hlt">water</span> (PW) samples were less than ambient <span class="hlt">water</span> quality criteria for Cr(VI) (50 microg/L). Concentrations of dissolved total Cr in <span class="hlt">pore</span> <span class="hlt">water</span> ranged from <2.0 to 5.3 microg/L, while Cr(VI) was not detected (<10 microg/L). These findings are consistent with previous studies, which demonstrated limited bioavailability and toxicity of Cr in sediment at this site and others with similar conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/136213','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/136213"><span>Mapping the fluid flow of the Mariana Mounds ridge flank hydrothermal system: <span class="hlt">Pore</span> <span class="hlt">water</span> chemical tracers</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wheat, C.G.; McDuff, R.E.</p> <p>1995-05-10</p> <p>The authors present a conceptual model of fluid circulation in a ridge flank hydrothermal system, the Mariana Mounds. The model is based on chemical data from <span class="hlt">pore</span> <span class="hlt">waters</span> extracted from piston cores and from push cores collected by deep-sea research vessel Alvin in small, meter-sized mounds situated on a local topographic high. These mounds are located within a region of heat flow exceeding that calculated from a conductive model and are zones of strong <span class="hlt">pore</span> <span class="hlt">water</span> upflow. The authors have interpreted the chemical data with time-dependent transport-reaction models to estimate <span class="hlt">pore</span> <span class="hlt">water</span> velocities. In the mounds themselves <span class="hlt">pore</span> <span class="hlt">water</span> velocities reach several meters per year to kilometers per year. Within about 100 m from these zones of focused upflow velocities decrease to several centimeters per year up to tens of centimeters per year. A large area of low heat flow surrounds these heat flow and topographic highs, with upwelling <span class="hlt">pore</span> <span class="hlt">water</span> velocities less than 2 cm/yr. In some nearby cores, downwelling of bottom seawater is evident but at speeds less than 2 cm/yr. Downwelling through the sediments appears to be a minor source of seawater recharge to the basaltic basement. The authors conclude that the principal source of seawater recharge to basement is where basement outcrops exist, most likely a scarpt about 2-4 km to the east and southeast of the study area. 71 refs., 14 figs., 3 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22416023','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22416023"><span>Effect of the hydroaffinity and topology of <span class="hlt">pore</span> walls on the structure and dynamics of confined <span class="hlt">water</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Harrach, Michael F. Klameth, Felix; Drossel, Barbara; Vogel, Michael</p> <p>2015-01-21</p> <p>We perform molecular dynamics simulations to observe the structure and dynamics of SPC/E <span class="hlt">water</span> in amorphous silica <span class="hlt">pores</span> and amorphous ice <span class="hlt">pores</span> with radii slightly larger than 10 Å. In addition to atomically rough <span class="hlt">pores</span>, we construct completely smooth <span class="hlt">pores</span> such that the potential felt at a given distance from the <span class="hlt">pore</span> wall is an averaged atomic potential. As compared to rough walls, smooth walls induce stronger distortions of <span class="hlt">water</span> structure for both silica and ice confinements. On the other hand, unlike the smooth <span class="hlt">pores</span>, the rough <span class="hlt">pores</span> strongly slow down <span class="hlt">water</span> dynamics at the <span class="hlt">pore</span> wall. The slowdown vanishes when reducing the atomic charges in the wall, i.e., when varying the hydroaffinity, while keeping the surface topology, indicating that it is not a geometric effect. Rather, it is due to the fact that the wall atoms provide a static energy landscape along the surface, e.g., fixed anchor-points for hydrogen bonds, to which the <span class="hlt">water</span> molecules need to adapt, blocking channels for structural rearrangement. In the smooth <span class="hlt">pores</span>, <span class="hlt">water</span> dynamics can be faster than in the bulk liquid not only at the <span class="hlt">pore</span> wall but also in the <span class="hlt">pore</span> center. Changes in the tetrahedral order rather than in the local density are identified as the main cause for this change of the dynamical behavior in the center of smooth <span class="hlt">pores</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70031526','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70031526"><span>A simple <span class="hlt">pore</span> <span class="hlt">water</span> hydrogen diffusion syringe sampler</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Vroblesky, D.A.; Chapelle, F.H.; Bradley, P.M.</p> <p>2007-01-01</p> <p>Molecular hydrogen (H2) is an important intermediate product and electron donor in microbial metabolism. Concentrations of dissolved H 2 are often diagnostic of the predominant terminal electron-accepting processes in ground <span class="hlt">water</span> systems or aquatic sediments. H2 concentrations are routinely measured in ground <span class="hlt">water</span> monitoring wells but are rarely measured in saturated aquatic sediments due to a lack of simple and practical sampling methods. This report describes the design and development (including laboratory and field testing) of a simple, syringe-based H 2 sampler in (1) saturated, riparian sediments, (2) surface <span class="hlt">water</span> bed sediments, and (3) packed intervals of a fractured bedrock borehole that are inaccessible by standard pumped methods. ?? 2007 National Ground <span class="hlt">Water</span> Association.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23484767','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23484767"><span>Hydrophobic <span class="hlt">pore</span> array surfaces: wetting and interaction forces in <span class="hlt">water</span>/ethanol mixtures.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hansson, Petra M; Hormozan, Yashar; Brandner, Birgit D; Linnros, Jan; Claesson, Per M; Swerin, Agne; Schoelkopf, Joachim; Gane, Patrick A C; Thormann, Esben</p> <p>2013-04-15</p> <p>Interactions between and wetting behavior of structured hydrophobic surfaces using different concentrations of <span class="hlt">water</span>/ethanol mixtures have been investigated. Silica surfaces consisting of <span class="hlt">pore</span> arrays with different <span class="hlt">pore</span> spacings and <span class="hlt">pore</span> depths were made hydrophobic by silanization. Their static and dynamic contact angles were found to be independent of the <span class="hlt">pore</span> depth while fewer <span class="hlt">pores</span> on the surface, i.e. a closer resemblance to a flat surface, gave a lower contact angle. As expected, a higher amount of ethanol facilitated wetting on all the surfaces tested. Confocal Raman microscopy measurements proved both <span class="hlt">water</span> and ethanol to penetrate into the <span class="hlt">pores</span>. AFM colloidal probe force measurements clearly showed that formation of air cavitation was hindered between the hydrophobic surfaces in presence of ethanol, and an increase in ethanol concentration was followed by a smaller jump-in distance and a weaker adhesion force. On separation, an immediate jump-out of contact occurred. The measured forces were interpreted as being due to capillary condensation of ethanol between the surfaces giving rise to very unstable cavities immediately rupturing on surface separation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22656651','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22656651"><span>Ion transport through dimethyl sulfoxide (DMSO) induced transient <span class="hlt">water</span> <span class="hlt">pores</span> in cell membranes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>He, Fei; Liu, Weirong; Zheng, Shengchao; Zhou, Li; Ye, Benlan; Qi, Zhi</p> <p>2012-01-01</p> <p>It is well known that dimethyl sulphoxide (DMSO) increases membrane permeability, which makes it widely used as a vehicle to facilitate drug delivery across biological membranes. However, the mechanism of how DMSO increases membrane permeability has not been well understood. Recently, molecular dynamics simulations have demonstrated that DMSO can induce <span class="hlt">water</span> <span class="hlt">pores</span> in biological membranes, but no direct experimental evidence is so far available to prove the simulation result. Using FluxOR Tl⁺ influx assay and intracellular Ca²⁺ imaging technique, we studied the effect of DMSO on Tl⁺ and Ca²⁺ permeation across cell membranes. Upon application of DMSO on CHO-K1 cell line, Tl⁺ influx was transiently increased in a dose-dependent manner. The increase in Tl⁺ permeability induced by DMSO was not changed in the presence of blockers for K⁺ channel and Na⁺-K⁺ ATPase, suggesting that Tl⁺ permeates through transient <span class="hlt">water</span> <span class="hlt">pores</span> induced by DMSO to enter into the cell. In addition, Ca²⁺ permeability was significantly increased upon application of DMSO, indicating that the transient <span class="hlt">water</span> <span class="hlt">pores</span> induced by DMSO were non-selective <span class="hlt">pores</span>. Furthermore, similar results could be obtained from RAW264.7 macrophage cell line. Therefore, this study provided experimental evidence to support the prediction that DMSO can induce transient <span class="hlt">water</span> <span class="hlt">pores</span> in cell membranes, which in turn facilitates the transport of active substances across membranes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/141734','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/141734"><span>Characterizing <span class="hlt">pore</span> sizes and <span class="hlt">water</span> structure in stimuli-responsive hydrogels</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hoffman, A.S.; Antonsen, K.P.; Ashida, T.; Bohnert, J.L.; Dong, L.C.; Nabeshima, Y.; Nagamatsu, S.; Park, T.G.; Sheu, M.S.; Wu, X.S.; Yan, Q.</p> <p>1993-12-31</p> <p>Hydrogels have been extensively investigated as potential matrices for drug delivery. In particular, hydrogels responsive to pH and temperature changes have been of greatest interest most recently. Proteins and peptide drugs are especially relevant for delivery from such hydrogel matrices due to the relatively {open_quotes}passive{close_quotes} and biocompatible microenvironment which should exist within the hydrogel aqueous <span class="hlt">pores</span>. The large molecular size of many proteins requires an interconnected large <span class="hlt">pore</span> structure. Furthermore, the gel <span class="hlt">pore</span> {open_quotes}walls{close_quotes} should not provide hydrophobic sites for strong interactions with proteins. In the special case of ion exchange release the protein would be attracted by opposite charges on the polymer backbones. Therefore, it is important both to control and to characterize the <span class="hlt">pore</span> structure and the <span class="hlt">water</span> character within a hydrogel to be used or protein or peptide drug delivery. This talk will critically review techniques for estimating these two key parameters in hydrogels.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AdWR...87...56X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AdWR...87...56X"><span>Effects of macro-<span class="hlt">pores</span> on <span class="hlt">water</span> flow in coastal subsurface drainage systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xin, Pei; Yu, Xiayang; Lu, Chunhui; Li, Ling</p> <p>2016-01-01</p> <p>Leaching through subsurface drainage systems has been widely adopted to ameliorate saline soils. The application of this method to remove salt from reclaimed lands in the coastal zone, however, may be impacted by macro-<span class="hlt">pores</span> such as crab burrows, which are commonly distributed in the soils. We developed a three-dimensional model to investigate <span class="hlt">water</span> flow in subsurface drainage systems affected by macro-<span class="hlt">pores</span> distributed deterministically and randomly through Monte Carlo simulations. The results showed that, for subsurface drainage systems under the condition of continuous surface ponding, macro-<span class="hlt">pores</span> increased the hydraulic head in the deep soil, which in turn reduced the hydraulic gradient between the surface and deep soil. As a consequence, <span class="hlt">water</span> infiltration across the soil surface was inhibited. Since salt transport in the soil is dominated by advection, the flow simulation results indicated that macro-<span class="hlt">pores</span> decreased the efficiency of salt leaching by one order of magnitude, in terms of both the elapsed time and the amount of <span class="hlt">water</span> required to remove salt over the designed soil leaching depth (0.6 m). The reduction of the leaching efficiency was even greater in drainage systems with a layered soil stratigraphy. Sensitivity analyses demonstrated that with an increased penetration depth or density of macro-<span class="hlt">pores</span>, the leaching efficiency decreased further. The revealed impact of macro-<span class="hlt">pores</span> on <span class="hlt">water</span> flow represents a significant shortcoming of the salt leaching technique when applied to coastal saline soils. Future designs of soil amelioration schemes in the coastal zone should consider and aim to minimize the bypassing effect caused by macro-<span class="hlt">pores</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016HydJ...24.1821B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016HydJ...24.1821B"><span>Prediction of <span class="hlt">pore-water</span> pressure response to rainfall using support vector regression</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Babangida, Nuraddeen Muhammad; Mustafa, Muhammad Raza Ul; Yusuf, Khamaruzaman Wan; Isa, Mohamed Hasnain</p> <p>2016-11-01</p> <p>Nonlinear complex behavior of <span class="hlt">pore-water</span> pressure responses to rainfall was modelled using support vector regression (SVR). <span class="hlt">Pore-water</span> pressure can rise to disturbing levels that may result in slope failure during or after rainfall. Traditionally, monitoring slope <span class="hlt">pore-water</span> pressure responses to rainfall is tedious and expensive, in that the slope must be instrumented with necessary monitors. Data on rainfall and corresponding responses of <span class="hlt">pore-water</span> pressure were collected from such a monitoring program at a slope site in Malaysia and used to develop SVR models to predict <span class="hlt">pore-water</span> pressure fluctuations. Three models, based on their different input configurations, were developed. SVR optimum meta-parameters were obtained using k-fold cross validation and a grid search. Model type 3 was adjudged the best among the models and was used to predict three other points on the slope. For each point, lag intervals of 30 min, 1 h and 2 h were used to make the predictions. The SVR model predictions were compared with predictions made by an artificial neural network model; overall, the SVR model showed slightly better results. Uncertainty quantification analysis was also performed for further model assessment. The uncertainty components were found to be low and tolerable, with d-factor of 0.14 and 74 % of observed data falling within the 95 % confidence bound. The study demonstrated that the SVR model is effective in providing an accurate and quick means of obtaining <span class="hlt">pore-water</span> pressure response, which may be vital in systems where response information is urgently needed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000GeCoA..64.3995A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000GeCoA..64.3995A"><span>Geochemical dynamics of the Atlantis II Deep (Red Sea): II. Composition of metalliferous sediment <span class="hlt">pore</span> <span class="hlt">waters</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Anschutz, Pierre; Blanc, Gérard; Monnin, Christophe; Boulègue, Jacques</p> <p>2000-12-01</p> <p>The Atlantis II Deep is an axial depression of the Red Sea filled with highly saline brines and covered by layered metalliferous sediment. We report new data on the vertical distribution of major salts and trace metals dissolved in the <span class="hlt">pore</span> <span class="hlt">waters</span> of the metalliferous sediments. We have studied the chemical composition of interstitial <span class="hlt">waters</span> of two sediment cores of the western (core 684) and southwestern (core 683) basins. The major dissolved elements are Na and Cl. Their concentrations are close to those of the brine overlying the sediment. The <span class="hlt">pore</span> <span class="hlt">waters</span> are undersaturated with respect to halite at the in situ conditions (62°C, 220 bars), but are saturated at the shipboard conditions (10°C, 1 bar). The salt and <span class="hlt">water</span> contents of the bulk sediment show that core 683 contained halite in the solid fraction. A part of it precipitated after core collection, but most of it was present in situ. Thermodynamic calculations with a <span class="hlt">water</span>-rock interaction model based on Pitzer's ion interaction approach reveal that equilibrium between the <span class="hlt">pore</span> <span class="hlt">waters</span> and anhydrite is achieved in sediment layers for which observations report the presence of this mineral. We used a transport model, which shows that molecular diffusion can smooth the profile of dissolved salt and partly erase the <span class="hlt">pore</span> <span class="hlt">water</span> record of past variations of salinity in the lower brine. For example, we calculated that the <span class="hlt">pore</span> <span class="hlt">water</span> record of modern variation of brine salinity is rapidly smoothed by molecular diffusion. The dissolved transition metals show large variations with depth in the interstitial <span class="hlt">waters</span>. The profiles of core 683 reflect the possible advection of hydrothermal fluid within the sediment of the southwestern basin. The distribution of dissolved metals in core 684 is the result of diagenetic reactions, mainly the reduction of Mn-oxide with dissolved Fe(II), the recrystallization of primary oxide minerals, and the precipitation of authigenic Mn-carbonates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/hi0798.photos.367395p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/hi0798.photos.367395p/"><span>Overview of the <span class="hlt">Marine</span> Railway No. 2 from the <span class="hlt">water</span>'s ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>Overview of the <span class="hlt">Marine</span> Railway No. 2 from the <span class="hlt">water</span>'s edge to Facility 233 - U.S. Naval Base, Pearl Harbor, <span class="hlt">Marine</span> Railway No. 2, Near intersection of Avenue G & Third Street, Pearl City, Honolulu County, HI</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1170501','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1170501"><span>Field Test Design Simulations of <span class="hlt">Pore-Water</span> Extraction for the SX Tank Farm</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Truex, Michael J.; Oostrom, Martinus</p> <p>2013-09-01</p> <p>A proof of principle test of <span class="hlt">pore</span> <span class="hlt">water</span> extraction is being performed by Washington River Protection Solutions for the U.S. Department of Energy, Office of River Protection. This test is being conducted to meet the requirements of Hanford Federal Facility Agreement and Consent Order (HFFACO) (Ecology et al. 1989) Milestone M 045-20, and is described in RPP-PLAN-53808, 200 West Area Tank Farms Interim Measures Investigation Work Plan. To support design of this test, numerical simulations were conducted to help define equipment and operational parameters. The modeling effort builds from information collected in laboratory studies and from field characterization information collected at the test site near the Hanford Site 241-SX Tank Farm. Numerical simulations were used to evaluate <span class="hlt">pore-water</span> extraction performance as a function of the test site properties and for the type of extraction well configuration that can be constructed using the direct-push installation technique. Output of simulations included rates of <span class="hlt">water</span> and soil-gas production as a function of operational conditions for use in supporting field equipment design. The simulations also investigated the impact of subsurface heterogeneities in sediment properties and moisture distribution on <span class="hlt">pore-water</span> extraction performance. Phenomena near the extraction well were also investigated because of their importance for <span class="hlt">pore-water</span> extraction performance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11257871','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11257871"><span><span class="hlt">Pore</span> distribution effect of activated carbon in adsorbing organic micropollutants from natural <span class="hlt">water</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ebie, K; Li, F; Azuma, Y; Yuasa, A; Hagishita, T</p> <p>2001-01-01</p> <p>Adsorption isotherms of organic micropollutants in coexistence with natural organic matter (NOM) were analyzed to evaluate the impacts of <span class="hlt">pore</span> size distribution of activated carbon (AC) on the competition effects of the NOM. Single solute adsorption experiments and simultaneous adsorption experiments with NOM contained in a coagulation-pretreated surface <span class="hlt">water</span> were performed for four agricultural chemicals and three coal-based activated carbons (ACs) having different <span class="hlt">pore</span> distributions. The results showed that, for all the carbons used, the adsorption capacity of the chemicals was reduced distinctly in the presence of NOM. Such a reduction was more apparent for AC with a larger portion of small <span class="hlt">pores</span> suitable for the adsorption of small organic molecules and for the agricultural chemicals with a more hydrophilic nature. Ideal adsorbed solution theory (IAST) incorporated with the Freundlich isotherm expression (IAST-Freundlich model) could not interpret the impact of NOM on the adsorption capacity of the chemicals unless a <span class="hlt">pore</span> blockage effect caused by the adsorption of NOM was also considered. By taking into account this effect, the adsorption isotherm of the chemicals in the presence of NOM was well described, and the capacity reduction caused by the NOM was quantitatively assessed from the viewpoints of the site competition and the <span class="hlt">pore</span> blockage. Analytical results clearly indicated that <span class="hlt">pore</span> blockage was an important competition mechanism that contributed to 10-99% of the total capacity reductions of the chemicals, the level depended greatly on the ACs, the chemicals and the equilibrium concentrations, and could possibly be alleviated by broadening the <span class="hlt">pore</span> size distributions of the ACs to provide a large volume percentage for <span class="hlt">pores</span> with sizes above 30 A.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4461045','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4461045"><span>Polymerization and Functionalization of Membrane <span class="hlt">Pores</span> for <span class="hlt">Water</span> Related Applications</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2015-01-01</p> <p>Poly(vinylidene fluoride) (PVDF) was modified by chemical treatments in order to create active double bonds to obtain covalent grafting of poly(acrylic acid) (PAA) on membrane. The attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectrum confirms the formation of conjugated C=C double bonds with surface dehydrofluorination. The membrane morphology was studied by scanning electron microscopy (SEM). The surface composition was characterized by X-ray photoelectron spectroscopy (XPS). The thermal stability of the dehydrofluorinated membrane (Def-PVDF) and functionalized membranes were investigated by differential scanning calorimetry (DSC) analysis. The influence of covalently attached PAA on Def-PVDF membrane has been investigated to determine its effect on the transport of <span class="hlt">water</span> and charged solute. Variations in the solution pH show an effect on both permeability and solute retention in a reversible fashion. Metal nanoparticles were also immobilized in the membrane for the degradation of toxic chlorinated organics from <span class="hlt">water</span>. In addition, PVDF membranes with an asymmetric and sponge-like morphology were developed by immersion-precipitation phase-inversion methods in both lab-scale and large-scale. The new type of spongy PVDF membrane shows high surface area with higher yield of PAA functionalization. The ion-capacity with Ca2+ ions was also investigated. PMID:26074669</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26074669','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26074669"><span>Polymerization and Functionalization of Membrane <span class="hlt">Pores</span> for <span class="hlt">Water</span> Related Applications.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xiao, Li; Davenport, Douglas M; Ormsbee, Lindell; Bhattacharyya, Dibakar</p> <p>2015-04-29</p> <p>Poly(vinylidene fluoride) (PVDF) was modified by chemical treatments in order to create active double bonds to obtain covalent grafting of poly(acrylic acid) (PAA) on membrane. The attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectrum confirms the formation of conjugated C=C double bonds with surface dehydrofluorination. The membrane morphology was studied by scanning electron microscopy (SEM). The surface composition was characterized by X-ray photoelectron spectroscopy (XPS). The thermal stability of the dehydrofluorinated membrane (Def-PVDF) and functionalized membranes were investigated by differential scanning calorimetry (DSC) analysis. The influence of covalently attached PAA on Def-PVDF membrane has been investigated to determine its effect on the transport of <span class="hlt">water</span> and charged solute. Variations in the solution pH show an effect on both permeability and solute retention in a reversible fashion. Metal nanoparticles were also immobilized in the membrane for the degradation of toxic chlorinated organics from <span class="hlt">water</span>. In addition, PVDF membranes with an asymmetric and sponge-like morphology were developed by immersion-precipitation phase-inversion methods in both lab-scale and large-scale. The new type of spongy PVDF membrane shows high surface area with higher yield of PAA functionalization. The ion-capacity with Ca(2+) ions was also investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70026071','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70026071"><span>A multi-level <span class="hlt">pore-water</span> sampler for permeable sediments</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Martin, J.B.; Hartl, K.M.; Corbett, D.R.; Swarzenski, P.W.; Cable, J.E.</p> <p>2003-01-01</p> <p>The construction and operation of a multi-level piezometer (multisampler) designed to collect <span class="hlt">pore</span> <span class="hlt">water</span> from permeable sediments up to 230 cm below the sediment-<span class="hlt">water</span> interface is described. Multisamplers are constructed from 1 1/2 inch schedule 80 PVC pipe. One-quarter-inch flexible PVC tubing leads from eight ports at variable depths to a 1 1/2 inch tee fitting at the top of the PVC pipe. Multisamplers are driven into the sediments using standard fence-post drivers. <span class="hlt">Water</span> is pumped from the PVC tubing with a peristaltic pump. Field tests in Banana River Lagoon, Florida, demonstrate the utility of multisamplers. These tests include collection of multiple samples from the permeable sediments and reveal mixing between shallow <span class="hlt">pore</span> <span class="hlt">water</span> and overlying lagoon <span class="hlt">water</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1810516Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1810516Q"><span>Relating soil <span class="hlt">pore</span> geometry to soil <span class="hlt">water</span> content dynamics decomposed at multiple frequencies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qin, Mingming; Gimenez, Daniel; Cooper, Miguel</p> <p>2016-04-01</p> <p>Soil structure is a critical factor determining the response of soil <span class="hlt">water</span> content to meteorological inputs such as precipitation. Wavelet analysis can be used to filter a signal into several wavelet components, each characterizing a given frequency. The purpose of this research was to investigate relationships between the geometry of soil <span class="hlt">pore</span> systems and the various wavelet components derived from soil <span class="hlt">water</span> content dynamics. The two study sites investigated were located in the state of São Paulo, Brazil. Each site was comprised of five soil profiles, the first site was situated along a 300-meter transect with about 10% slope in a tropical semi-deciduous forest, while the second one spanned 230-meter over a Brazilian savanna with a slope of about 6%. For each profile, between two to four <span class="hlt">Water</span> Content Reflectometer CS615 (Campbell Scientific, Inc.) probes were installed according to horizonation at depths varying between 0.1 m and 2.3 m. Bulk soil, three soil cores, and one undisturbed soil block were sampled from selected horizons for determining particle size distributions, <span class="hlt">water</span> retention curves, and <span class="hlt">pore</span> geometry, respectively. <span class="hlt">Pore</span> shape and size were determined from binary images obtained from resin-impregnated blocks and used to characterize <span class="hlt">pore</span> geometry. Soil <span class="hlt">water</span> contents were recorded at a 20-minute interval over a 4-month period. The Mexican hat wavelet was used to decompose soil <span class="hlt">water</span> content measurements into wavelet components. The responses of wavelet components to wetting and drying cycles were characterized by the median height of the peaks in each wavelet component and were correlated with particular <span class="hlt">pore</span> shapes and sizes. For instance, large elongated and irregular <span class="hlt">pores</span>, largely responsible for the transmission of <span class="hlt">water</span>, were significantly correlated with wavelet components at high frequencies (40 minutes to 48 hours) while rounded <span class="hlt">pores</span>, typically associated to <span class="hlt">water</span> retention, were only significantly correlated to lower frequency ranges</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JAG...135..474P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JAG...135..474P"><span>On the <span class="hlt">pore</span> <span class="hlt">water</span> chemistry effect on spectral induced polarization measurements in the presence of pyrite</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Placencia-Gómez, Edmundo; Slater, Lee D.</p> <p>2016-12-01</p> <p>In order to expand the application of the induced polarization (IP) method as a technique for monitoring metallic mineral dissolution and precipitation mechanisms, we studied the effects of variations in <span class="hlt">pore</span> <span class="hlt">water</span> chemistry on the spectral induced polarization (SIP) response of a mixture of silica-sand and pyrite particles in the laboratory. We investigated the dependence of the SIP response on both <span class="hlt">pore</span> <span class="hlt">water</span> conductivity and pH for various chemical compositions: redox-passive (P) versus redox-active (A) ions, using CaCl2 as P-ions, and FeSO4 and FeCl3 as A-ion brines. The effect of <span class="hlt">pore</span> <span class="hlt">water</span> chemistry was evaluated by means of a recently proposed volumetric specific capacitance model. The SIP response (IP-effect) was primarily determined by the <span class="hlt">pore</span> <span class="hlt">water</span> conductivity and the specific capacitance was only weakly dependent on the chemical composition and pHw. We found that the specific capacitance varies to first order over a limited range and approximates a single value (≈ 302 F m- 3 in average). However, variations in the specific capacitance as a function of active versus inactive ion chemistry might be important to consider when using IP to monitor specific mineral dissolution and precipitation processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=289056','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=289056"><span><span class="hlt">Pore-water</span> pressures associated with clogging of soil pipes: Numerical analysis of laboratory experiments</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>Clogging of soil pipes due to excessive internal erosion has been hypothesized to cause extreme erosion events such as landslides, debris flows, and gullies, but confirmation of this phenomenon has been lacking. Laboratory and field measurements have failed to measure <span class="hlt">pore</span> <span class="hlt">water</span> pressures within pip...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MS%26E...96a2011B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MS%26E...96a2011B"><span><span class="hlt">Pore</span> Distribution and <span class="hlt">Water</span> Uptake in a Cenosphere-Cement Paste Composite Material</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baronins, J.; Setina, J.; Sahmenko, G.; Lagzdina, S.; Shishkin, A.</p> <p>2015-11-01</p> <p>Alumina silicate cenospheres (CS) is a significant waste material from power plants that use a coal. Use CS as Portland cement replacement material gives opportunity to control physical and mechanical properties and makes a product lighter and more cost-effective. In the frame of this study, Portland cement paste samples were produced by adding CS in the concentration range from 0 to 40 volume %. <span class="hlt">Water</span> uptake of hardened samples was checked and <span class="hlt">pore</span> size distribution by using the mercury porosimetry was determined. In a cold climate where the temperature often falls below 0 °C, it is important to avoid the amount of micrometer sized <span class="hlt">pores</span> in the final structure and to decrease <span class="hlt">water</span> absorption capacity of material. In winter conditions, <span class="hlt">water</span> fills such <span class="hlt">pores</span> and causes additional stresses to their walls by expansion while freezing. It was found that generally <span class="hlt">water</span> uptake capacity for cement paste samples decreased up to 20% by increasing the concentration of CS up to 40 volume %, at the same time, the volume of micrometer sized opened <span class="hlt">pores</span> increases.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_6 --> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18302968','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18302968"><span>Mobility of trace metals in <span class="hlt">pore</span> <span class="hlt">waters</span> of two Central European peat bogs.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Novak, Martin; Pacherova, Petra</p> <p>2008-05-15</p> <p>Vertical peat profiles can only be used as archives of past changes in pollution levels if atmogenic elements are immobile after their burial. For mobile elements, similar <span class="hlt">pore-water</span> concentrations can be expected at different peat depths. Concentrations of Pb, Cu, Zn, Cr, Mn, Fe, Co and Cd were determined in surface bog <span class="hlt">water</span> and bog <span class="hlt">pore</span> <span class="hlt">water</span> 40 cm below surface in two Sphagnum-dominated peat bogs in the Czech Republic. Velke jerabi jezero (VJJ) is an upland bog located in an industrial area, Cervene blato (CB) is a lowland bog located in a rural area. Metal concentrations were monitored seasonally over 3 years (2002--2005) at both sites. Higher concentrations of Pb, Cu, Zn, Cr and Cd and lower concentrations of Mn, Fe and Co were found at the less polluted CB compared to VJJ. No clear-cut seasonality was observed in metal concentrations in bog <span class="hlt">waters</span>, despite seasonal differences in industrial emission rates of pollutants (more coal burning in winter than in summer). This contrasts with an earlier observation of distinct seasonality in sulfate concentration and isotope composition in these stagnating bog <span class="hlt">waters</span>. Peat substrate 40 cm below current bog surface represented pre-industrial low-pollution environment, yet <span class="hlt">pore</span> <span class="hlt">waters</span> at such depths contained the same metal concentrations as surface <span class="hlt">waters</span>. The only exception was Pb, whose concentration in <span class="hlt">water</span> solutes increased with increasing depth. Lack of vertical stratification in <span class="hlt">pore-water</span> contents of Cu, Zn, Cr, Mn, Fe and Co indicated vertical mobility of these metals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014WRR....50.4760J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014WRR....50.4760J"><span>Hydrology and <span class="hlt">pore</span> <span class="hlt">water</span> chemistry in a permafrost wetland, Ilulissat, Greenland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jessen, Søren; Holmslykke, Hanne D.; Rasmussen, Kristine; Richardt, Niels; Holm, Peter E.</p> <p>2014-06-01</p> <p>Hydrological and geochemical processes controlling the <span class="hlt">pore</span> <span class="hlt">water</span> chemistry in a permafrost wetland, with loam overlain by sphagnum peat, were investigated. The vertical distributions of dissolved Cl, and of <span class="hlt">pore</span> <span class="hlt">water</span> δ18O, appeared unrelated to ion freeze-out and isotope ice-<span class="hlt">water</span> fractionation processes, respectively, dismissing solute freeze-out as a main control on the <span class="hlt">water</span> chemistry. However, concentrations of major ions, others than Cl, generally increased with depth into the active layer. A conceptual model for <span class="hlt">water</span> and solute movement in the active layer was derived. The model indicates upward diffusive transport of elements, released in the loam layer by mineral weathering, to the peat layer, in which lateral advective transport dominates. Active layer <span class="hlt">pore</span> <span class="hlt">water</span> and <span class="hlt">water</span> of melted core sections of permafrost were of Ca-Mg-HCO3 type (1:1:4 stoichiometry) and were subsaturated for calcite and dolomite. The results are consistent with an annual cycling of inorganic carbon species, Ca and Mg, via cryogenic carbonate precipitation during fall freeze-up and their redissolution following spring thaw. Similarly, elevated Fe2+ concentrations appear to be related to cryogenic siderite formation. <span class="hlt">Pore</span> <span class="hlt">water</span> in the active layer showed high partial pressures of CO2, indicating the feasibility of bubble ebullition as a greenhouse gas emission pathway from permafrost wetlands. Elevated concentrations of geogenic trace elements (Ni, Al, and As) were observed, and the controlling geochemical processes are discussed. The conceptual model for <span class="hlt">water</span> and solute movement was applied to quantify the contribution of released trace elements to a downstream lake in the permafrost catchment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA....11169B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA....11169B"><span>Distribution of dissolved silver in <span class="hlt">marine</span> <span class="hlt">waters</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barriada, J. L.; Achterberg, E. P.; Tappin, A.; Truscott, J.</p> <p>2003-04-01</p> <p>Silver is one of the most toxic heavy metals, surpassed only by mercury [1-3]. Monitoring of dissolved silver concentrations in natural <span class="hlt">waters</span> is therefore of great importance. The determination of dissolved silver in <span class="hlt">waters</span> is not without challenges, because of its low (picomolar) concentrations. Consequently, there are only a few reported studies in <span class="hlt">marine</span> <span class="hlt">waters</span>, which have been performed in USA [4-6] and Japan [7]. The analytical techniques used in the reported studies for the determination of silver in seawater were Graphite Furnace Atomic Absorption Spectroscopy (GFAAS) after solvent extraction [2,4,5], and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) after solvent extraction or solid phase extraction [7,8]. In this contribution, we will present an optimised Magnetic Sector (MS) ICP-MS technique for the determination of dissolved silver in <span class="hlt">marine</span> <span class="hlt">waters</span>. The MS-ICP-MS method used anion exchange column to preconcentrate silver from saline <span class="hlt">waters</span>, and to remove the saline matrix. The ICP-MS method has been used successfully to determine total dissolved silver in estuarine and oceanic samples. Bibliography 1. H. T. Ratte, Environ. Toxicol. Chem. 1999, 18: p. 89-108. 2. R. T. Herrin, A. W. Andren and D. E. Armstrong, Environ. Sci. Technol. 2001, 35: 1953-1958. 3. D. E. Schildkraut, P. T. Dao, J. P. Twist, A. T. Davis and K. A. Robillard, Environ. Toxicol. Chem. 1998, 17: 642-649. 4. E. Breuer, S. A. Sanudo-Wilhelmy and R. C. Aller, Estuaries. 1999, 22:603-615. 5. A. R. Flegal, S. A. Sanudowilhelmy and G. M. Scelfo, Mar. Chem. 1995, 49: 315-320. 6. S. N. Luoma, Y. B. Ho and G. W. Bryan, Mar. Pollut. Bull. 1995, 31: 44-54. 7. Y. Zhang, H. Amakawa and Y. Nozaki, Mar. Chem. 2001, 75: 151-163. 8. L. Yang and R. E. Sturgeon, J. Anal. At. Spectrom. 2002, 17: 88-93.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1185491','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1185491"><span><span class="hlt">Water</span> Desalination Using Nanoporous Single-Layer Graphene with Tunable <span class="hlt">Pore</span> Size</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Surwade, Sumedh P.; Smirnov, Sergei N.; Vlassiouk, Ivan V.; Unocic, Raymond R.; Veith, Gabriel M.; Dai, Sheng; Mahurin, Shannon Mark</p> <p>2015-03-23</p> <p>Graphene has great potential to serve as a separation membrane due to its unique properties such as chemical and mechanical stability, flexibility and most importantly its one-atom thickness. In this study, we demonstrate first experimental evidence of the use of single-layer porous graphene as a desalination membrane. Nanometer-sized <span class="hlt">pores</span> are introduced into single layer graphene using a convenient oxygen plasma etching process that permits tuning of the <span class="hlt">pore</span> size. The resulting porous graphene membrane exhibited high rejection of salt ions and rapid <span class="hlt">water</span> transport, thus functioning as an efficient <span class="hlt">water</span> desalination membrane. Salt rejection selectivity of nearly 100% and exceptionally high <span class="hlt">water</span> fluxes exceeding 105 g m-2 s-1 at 40 C were measured using saturated <span class="hlt">water</span> vapor as a driving force.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1185491-water-desalination-using-nanoporous-single-layer-graphene-tunable-pore-size','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1185491-water-desalination-using-nanoporous-single-layer-graphene-tunable-pore-size"><span><span class="hlt">Water</span> Desalination Using Nanoporous Single-Layer Graphene with Tunable <span class="hlt">Pore</span> Size</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Surwade, Sumedh P.; Smirnov, Sergei N.; Vlassiouk, Ivan V.; ...</p> <p>2015-03-23</p> <p>Graphene has great potential to serve as a separation membrane due to its unique properties such as chemical and mechanical stability, flexibility and most importantly its one-atom thickness. In this study, we demonstrate first experimental evidence of the use of single-layer porous graphene as a desalination membrane. Nanometer-sized <span class="hlt">pores</span> are introduced into single layer graphene using a convenient oxygen plasma etching process that permits tuning of the <span class="hlt">pore</span> size. The resulting porous graphene membrane exhibited high rejection of salt ions and rapid <span class="hlt">water</span> transport, thus functioning as an efficient <span class="hlt">water</span> desalination membrane. Salt rejection selectivity of nearly 100% and exceptionallymore » high <span class="hlt">water</span> fluxes exceeding 105 g m-2 s-1 at 40 C were measured using saturated <span class="hlt">water</span> vapor as a driving force.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005ECSS...62..233K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005ECSS...62..233K"><span>Salt marsh <span class="hlt">pore</span> <span class="hlt">water</span> geochemistry does not correlate with microbial community structure</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Koretsky, Carla M.; Van Cappellen, Philippe; DiChristina, Thomas J.; Kostka, Joel E.; Lowe, Kristi L.; Moore, Charles M.; Roychoudhury, Alakendra N.; Viollier, Eric</p> <p>2005-01-01</p> <p>Spatial and temporal trends in <span class="hlt">pore</span> <span class="hlt">water</span> geochemistry and sediment microbial community structure are compared at three intertidal sites of a saltmarsh on Sapelo Island, GA. The sites include a heavily bioturbated, unvegetated creek bank, a levee with dense growth of Spartina alterniflora, and a more sparsely vegetated ponded marsh site. The redox chemistry of the <span class="hlt">pore</span> <span class="hlt">waters</span> ranges from sulfide-dominated at the ponded marsh site to suboxic at the creek bank site. At the three sites, the vertical redox stratification of the <span class="hlt">pore</span> <span class="hlt">waters</span> is more compressed in summer than in winter. The trends in redox chemistry reflect opposing effects of sediment respiration and <span class="hlt">pore</span> <span class="hlt">water</span> irrigation. Intense and deep burrowing activity by fiddler crabs at the creek bank site results in the efficient oxidation of reduced byproducts of microbial metabolism and, hence, the persistence of suboxic conditions to depths of 50 cm below the sediment surface. Increased supply of labile organic substrates at the vegetated sites promotes microbial degradation processes, leading to sharper redox gradients. At the levee site, this is partly offset by the higher density and deeper penetration of roots and macrofaunal burrows. Surprisingly, the microbial community structure shows little correlation with the variable vertical redox zonation of the <span class="hlt">pore</span> <span class="hlt">waters</span> across the saltmarsh. At the three sites, the highest population densities of aerobic microorganisms, iron- plus manganese-reducing bacteria, and sulfate reducers coexist within the upper 10 cm of sediment. The absence of a clear vertical separation of these microorganisms is ascribed to the high supply of labile organic matter and intense mixing of the topmost sediment via bioturbation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/AD0669506','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/AD0669506"><span>REPRODUCTIVE PERIODICITIES OF <span class="hlt">MARINE</span> ANIMALS OF TROPICAL MIDDLE EAST <span class="hlt">WATERS</span>.</span></a></p> <p><a target="_blank" href="https://publicaccess.dtic.mil/psm/api/service/search/search">DTIC Science & Technology</a></p> <p></p> <p></p> <p>AQUATIC ANIMALS, REPRODUCTION(PHYSIOLOGY), <span class="hlt">MARINE</span> BIOLOGY, BIOLOGICAL RHYTHMS, ECHINODERMATA , MOLLUSCA, CRUSTACEA, PERIODIC VARIATIONS, SEA <span class="hlt">WATER</span>, TEMPERATURE, INLAND WATERWAYS, RED SEA, MIDDLE EAST.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3887386','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3887386"><span>Paradoxical One-ion <span class="hlt">Pore</span> Behavior of the Long β-Helical Peptide of <span class="hlt">Marine</span> Cytotoxic Polytheonamide B</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Iwamoto, Masayuki; Matsunaga, Shigeki; Oiki, Shigetoshi</p> <p>2014-01-01</p> <p>The cytotoxic 48-mer peptide, polytheonamide B (pTB), from a <span class="hlt">marine</span> sponge forms a β6.3-helix with an inner diameter of 4 Å and a length of 45 Å, features that allow the selective permeation of monovalent cations across targeted cell membranes. To characterize this long, narrow <span class="hlt">pore</span>, electrophysiological examination using a planar lipid bilayer method was performed. The single-channel current amplitude exhibited saturation for concentrated Cs+ or K+ solution, and the reversal potential in mixed solutions did not exhibit any anomalous mole-fraction behavior. These results suggest the one-ion permeation mechanism. This is in contrast to the short (26 Å) β6.3-helical gramicidin channel, which holds two ions simultaneously. The paradoxical one-ion permeation through the long pTB channel was modeled with a discrete-state Markov model. Ions permeate through the channel by stepping between two binding sites in the <span class="hlt">pore</span>, but never occupy these sites simultaneously in either pure or mixed ion solution. PMID:24407373</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/671925','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/671925"><span>Isotopic data of <span class="hlt">pore</span> <span class="hlt">water</span> extracted from unsaturated-zone cores at Yucca Mountain, Nevada</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yang, I.C.</p> <p>1997-12-01</p> <p>Isotopic compositions of unsaturated-zone (UZ) ground <span class="hlt">water</span> ({delta}{sup 18}O, {delta}D, {delta}{sup 13}C and {sup 14}C) at Yucca Mountain, Nevada, the site of a potential permanent national nuclear waste repository, can be used to infer the origins of <span class="hlt">water</span>, residence times of the <span class="hlt">water</span>, <span class="hlt">water</span> flux, climatic and evaporative history of <span class="hlt">water</span>, flow paths and velocities. These data can also be used as indicators of transport properties or <span class="hlt">water</span>-rock interaction. The lack of long-term direct measurements of infiltration requires proxy indicators of <span class="hlt">water</span> movement through the unsaturated zone to extend the record into the past. This report will discuss {delta}D and {delta}{sup 18}O data obtained from <span class="hlt">pore</span> <span class="hlt">water</span>, along with the {delta}{sup 13}C and {sup 14}C data of gas and <span class="hlt">water</span> obtained from four boreholes dry-drilled through all UZ lithologic units to infer the existence of nonvertical flowpaths through the mountain and residence times of <span class="hlt">pore</span> <span class="hlt">water</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3108135','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3108135"><span>Temporal and Spatial <span class="hlt">Pore</span> <span class="hlt">Water</span> Pressure Distribution Surrounding a Vertical Landfill Leachate Recirculation Well</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kadambala, Ravi; Townsend, Timothy G.; Jain, Pradeep; Singh, Karamjit</p> <p>2011-01-01</p> <p>Addition of liquids into landfilled waste can result in an increase in <span class="hlt">pore</span> <span class="hlt">water</span> pressure, and this in turn may increase concerns with respect to geotechnical stability of the landfilled waste mass. While the impact of vertical well leachate recirculation on landfill <span class="hlt">pore</span> <span class="hlt">water</span> pressures has been mathematically modeled, measurements of these systems in operating landfills have not been reported. Pressure readings from vibrating wire piezometers placed in the waste surrounding a liquids addition well at a full-scale operating landfill in Florida were recorded over a 2-year period. Prior to the addition of liquids, measured <span class="hlt">pore</span> pressures were found to increase with landfill depth, an indication of gas pressure increase and decreasing waste permeability with depth. When liquid addition commenced, piezometers located closer to either the leachate injection well or the landfill surface responded more rapidly to leachate addition relative to those far from the well and those at deeper locations. After liquid addition stopped, measured <span class="hlt">pore</span> pressures did not immediately drop, but slowly decreased with time. Despite the large pressures present at the bottom of the liquid addition well, much smaller pressures were measured in the surrounding waste. The spatial variation of the pressures recorded in this study suggests that waste permeability is anisotropic and decreases with depth. PMID:21655145</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15836350','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15836350"><span>Thermodynamic functions of <span class="hlt">water</span> and ice confined to 2 nm radius <span class="hlt">pores</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tombari, E; Salvetti, G; Ferrari, C; Johari, G P</p> <p>2005-03-08</p> <p>The heat capacity C(p) of the liquid state of <span class="hlt">water</span> confined to 2 nm radius <span class="hlt">pores</span> in Vycor glass was measured by temperature modulation calorimetry in the temperature range of 253-360 K, with an accuracy of 0.5%. On nanoconfinement, C(p) of <span class="hlt">water</span> increases, and the broad minimum in the C(p) against T plot shifts to higher temperature. The increase in the C(p) of <span class="hlt">water</span> is attributed to an increase in the phonon and configurational contributions. The apparent heat capacity of the liquid and partially frozen state of confined <span class="hlt">water</span> was measured by temperature scanning calorimetry in the range of 240-280 K with an accuracy of 2%, both on cooling or heating at 6 K h(-1) rate. The enthalpy, entropy, and free energy of nanoconfined liquid <span class="hlt">water</span> have been determined. The apparent heat capacity remains higher than that of bulk ice at 240 K and it is concluded that freezing is incomplete at 240 K. This is attributed to the intergranular-<span class="hlt">water</span>-ice equilibrium in the <span class="hlt">pores</span>. The nanoconfined sample melts over a 240-268 K range. For 9.6 wt % nanoconfined <span class="hlt">water</span> concentration ( approximately 50% of the maximum filling) at 280 K, the enthalpy of <span class="hlt">water</span> is 81.6% of the bulk <span class="hlt">water</span> value and the entropy is 88.5%. For 21.1 wt % (100% filling) the corresponding values are 90.7% and 95.0%. The enthalpy decrease on nanoconfinement is a reflection of the change in the H-bonded structure of <span class="hlt">water</span>. The use of the Gibbs-Thomson equation for analyzing the data has been discussed and it is found that a distribution of <span class="hlt">pore</span> size does not entirely explain our results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EPJWC...614003L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EPJWC...614003L"><span>Change of microstructure of clays due to the presence of heavy metal ions in <span class="hlt">pore</span> <span class="hlt">water</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, X.; Saiyouri, N.; Hicher, P. Y.</p> <p>2010-06-01</p> <p>The compressibility of engineered barrier clays is, to a large extent, controlled by microstructure change due to the presence of chemical ions in clay-<span class="hlt">water</span> system. This paper aims to investigate the change of microstructure of clays due to the presence of heavy metal ions in <span class="hlt">pore</span> <span class="hlt">water</span>. We use two pure clays (kaolinite and bentonite) in the study. One-dimensional consolidation tests were performed on reconstituted samples, which are prepared with distilled <span class="hlt">water</span> and three types of heavy metal solutions (Pb(NO3)2, Cu(NO3)2, Zn(NO3)2,). In order to better understand the impact of chemical <span class="hlt">pore</span> fluid on microstructure of the two clays, following the consolidation test, scanning electron microscope (SEM) observations and mercury intrusion <span class="hlt">pore</span> size distribution measurements (MIP) were conducted. Due to the measurement range of MIP, which is only allowed to measure the minimal <span class="hlt">pore</span> size 20 Å, BET method by gas sorption, whose measurement <span class="hlt">pore</span> size range is from 3.5 Å to 500 Å, is used to measure the micropore size distribution. By this method, specific surface area of the soils can be also determined. It can be employed to demonstrate the difference of creep performance between the soils. Furthermore, a series of batch equilibrium tests were conducted to better understand the physical-chemical interactions between the particles of soils and the heavy metal ions. With the further consideration of the interparticle electrical attractive and repulsive force, an attempt has been made to predict the creep behaviour by using the modified Gouy-Chapman double layer theory. The results of calculation were compared with that of tests. The comparison shows that the prediction of compressibility of the clays according to the modified double diffuse layer theory can be reasonably agreement with the experimental data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26270848','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26270848"><span>Penetration Barrier of <span class="hlt">Water</span> through Graphynes' <span class="hlt">Pores</span>: First-Principles Predictions and Force Field Optimization.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bartolomei, Massimiliano; Carmona-Novillo, Estela; Hernández, Marta I; Campos-Martínez, José; Pirani, Fernando; Giorgi, Giacomo; Yamashita, Koichi</p> <p>2014-02-20</p> <p>Graphynes are novel two-dimensional carbon-based materials that have been proposed as molecular filters, especially for <span class="hlt">water</span> purification technologies. We carry out first-principles electronic structure calculations at the MP2C level of theory to assess the interaction between <span class="hlt">water</span> and graphyne, graphdiyne, and graphtriyne <span class="hlt">pores</span>. The computed penetration barriers suggest that <span class="hlt">water</span> transport is unfeasible through graphyne while being unimpeded for graphtriyne. For graphdiyne, with a <span class="hlt">pore</span> size almost matching that of <span class="hlt">water</span>, a low barrier is found that in turn disappears if an active hydrogen bond with an additional <span class="hlt">water</span> molecule on the opposite side of the opening is considered. Thus, in contrast with previous determinations, our results do not exclude graphdiyne as a promising membrane for <span class="hlt">water</span> filtration. In fact, present calculations lead to <span class="hlt">water</span> permeation probabilities that are 2 orders of magnitude larger than estimations based on common force fields. A new pair potential for the <span class="hlt">water</span>-carbon noncovalent component of the interaction is proposed for molecular dynamics simulations involving graphdiyne and <span class="hlt">water</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23542673','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23542673"><span>Small-scale variability in peatland <span class="hlt">pore-water</span> biogeochemistry, Hudson Bay Lowland, Canada.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ulanowski, T A; Branfireun, B A</p> <p>2013-06-01</p> <p>The Hudson Bay Lowland (HBL) of northern Ontario, Manitoba and Quebec, Canada is the second largest contiguous peatland complex in the world, currently containing more than half of Canada's soil carbon. Recent concerns about the ecohydrological impacts to these large northern peatlands resulting from climate change and resource extraction have catalyzed a resurgence in scientific research into this ecologically important region. However, the sheer size, heterogeneity and elaborate landscape arrangements of this ecosystem raise important questions concerning representative sampling of environmental media for chemical or physical characterization. To begin to quantify such variability, this study assessed the small-scale spatial (1m) and short temporal (21 day) variability of surface <span class="hlt">pore-water</span> biogeochemistry (pH, dissolved organic carbon, and major ions) in a Sphagnum spp.-dominated, ombrotrophic raised bog, and a Carex spp.-dominated intermediate fen in the HBL. In general, <span class="hlt">pore-water</span> pH and concentrations of dissolved solutes were similar to previously reported literature values from this region. However, systematic sampling revealed consistent statistically significant differences in <span class="hlt">pore-water</span> chemistries between the bog and fen peatland types, and large within-site spatiotemporal variability. We found that microtopography in the bog was associated with consistent differences in most biogeochemical variables. Temporal changes in dissolved solute chemistry, particularly base cations (Na(+), Ca(2+) and Mg(2+)), were statistically significant in the intermediate fen, likely a result of a dynamic connection between surficial <span class="hlt">waters</span> and mineral-rich deep groundwater. In both the bog and fen, concentrations of SO4(2-) showed considerable spatial variability, and a significant decrease in concentrations over the study period. The observed variability in peatland <span class="hlt">pore-water</span> biogeochemistry over such small spatial and temporal scales suggests that under-sampling in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/15014099','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/15014099"><span>Evaporative Evolution of Carbonate-Rich Brines from Synthetic Topopah Spring Tuff <span class="hlt">Pore</span> <span class="hlt">Water</span>, Yucca Mountain</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sutton, M; Alai, M; Carroll, S A</p> <p>2004-04-14</p> <p>The evaporation of a range of synthetic <span class="hlt">pore</span> <span class="hlt">water</span> solutions representative of the potential high-level-nuclear-waste repository at Yucca Mountain, NV is being investigated. The motivation of this work is to understand and predict the range of brine compositions that may contact the waste containers from evaporation of <span class="hlt">pore</span> <span class="hlt">waters</span>, because these brines could form corrosive thin films on the containers and impact their long-term integrity. A relatively complex synthetic Topopah Spring Tuff <span class="hlt">pore</span> <span class="hlt">water</span> was progressively concentrated by evaporation in a closed vessel, heated to 95 C in a series of sequential experiments. Periodic samples of the evaporating solution were taken to determine the evolving <span class="hlt">water</span> chemistry. According to chemical divide theory at 25 C and 95 C our starting solution should evolve towards a high pH carbonate brine. Results at 95 C show that this solution evolves towards a complex brine that contains about 99 mol% Na{sup +} for the cations, and 71 mol% Cl{sup -}, 18 mol% {Sigma}CO{sub 2}(aq), 9 mol%SO{sub 4}{sup 2-} for the anions. Initial modeling of the evaporating solution indicates precipitation of aragonite, halite, silica, sulfate and fluoride phases. The experiments have been used to benchmark the use of the EQ3/6 geochemical code in predicting the evolution of carbonate-rich brines during evaporation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19551886','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19551886"><span>Chloride ion conduction without <span class="hlt">water</span> coordination in the <span class="hlt">pore</span> of ClC protein.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ko, Youn Jo; Jo, Won Ho</p> <p>2010-02-01</p> <p>In the present work, we have found by an atomistic molecular dynamics simulation that hydrogen atoms originating from the residues of a prokaryotic ClC protein (EcClC) stabilize the chloride ion without <span class="hlt">water</span> molecules in the <span class="hlt">pore</span> of ClC protein. When the chloride ion conduction is simulated by pulling a chloride ion along the <span class="hlt">pore</span> axis, the free energy barrier for chloride ion conduction is calculated to be low (4 kcal/mol), although the chloride ion is stripped of its hydration shell as it passes through the dehydrated <span class="hlt">pore</span> region. The calculation of the number of hydrogen atoms surrounding the chloride ion reveals that <span class="hlt">water</span> molecules hydrating the chloride ion are replaced by polar and non-polar hydrogen atoms protruding from the protein residues. From the analysis of the pair interaction energy between the chloride ion and these hydrogen atoms, it is realized that the hydrogen atoms from the protein residues stabilize the chloride ion at the dehydrated region instead of <span class="hlt">water</span> molecules, by which the energetic penalty for detaching <span class="hlt">water</span> molecules from the permeating ion is compensated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70022821','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70022821"><span>Estimating methane production rates in bogs and landfills by deuterium enrichment of <span class="hlt">pore</span> <span class="hlt">water</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Siegel, D.I.; Chanton, J.P.; Glaser, P.H.; Chasar, L.S.; Rosenberry, D.O.</p> <p>2001-01-01</p> <p>Raised bogs and municipal waste landfills harbor large populations of methanogens within their domed deposits of anoxic organic matter. Although the methane emissions from these sites have been estimated by various methods, limited data exist on the activity of the methanogens at depth. We therefore analyzed the stable isotopic signature of the <span class="hlt">pore</span> <span class="hlt">waters</span> in two raised bogs from northern Minnesota to identify depth intervals in the peat profile where methanogenic metabolism occurs. Methanogenesis enriched the deuterium (2H) content of the deep peat <span class="hlt">pore</span> <span class="hlt">waters</span> by as much as +11% (Vienna Standard Mean Sea <span class="hlt">Water</span>), which compares to a much greater enrichment factor of +70% in leachate from New York City's Fresh Kills landfill. The bog <span class="hlt">pore</span> <span class="hlt">waters</span> were isotopically dated by tritium (3H) to be about 35 years old at 1.5 m depth, whereas the landfill leachate was estimated as ~ 17 years old from Darcy flow calculations. According to an isotopic mass balance the observed deuterium enrichment indicates that about 1.2 g of CH4m-3 d-1 were produced within the deeper peat, compared to about 2.8 g CH4 m-3 d-1 in the landfill. The values for methane production in the bog peat are substantially higher than the flux rates measured at the surface of the bogs or at the landfill, indicating that deeper methane production may be much higher than was previously assumed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/417922','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/417922"><span>Alkali-silica reaction and <span class="hlt">pore</span> solution composition in mortars in sea <span class="hlt">water</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kawamura, Mitsunori; Takeuchi, Katsunobu</p> <p>1996-12-01</p> <p>The promotion of expansion of mortars containing a reactive aggregate in 1N NaCl solution at 38 C was attributed to a rise of OH{sup {minus}} ion concentration in the <span class="hlt">pore</span> solution in the mortars. However, it is ambiguous whether the promotion of expansion of mortars in sea <span class="hlt">water</span> at a room temperature can be explained in the same way as in NaCl solution at an elevated temperature. This study aims at pursuing the expansion behavior of mortars containing a reactive aggregate relating it to their <span class="hlt">pore</span> solution composition and the extent of alkali-silica reaction occurring within reactive grains. The alkali-silica reaction in mortars in sea <span class="hlt">water</span> and 0.5 1N NaCl solution at 20 C appears to progress differently from that in mortars in 1N NaCl solution at an elevated temperature of 38 C. The promotion of expansion of mortars in sea <span class="hlt">water</span> at 20 C was found to be responsible for an effect of Cl{sup {minus}} ions in the alkali-silica reaction at early stages of immersion. Only when OH{sup {minus}} ion concentration in the <span class="hlt">pore</span> solution was relatively high, NaCl and sea <span class="hlt">water</span> could accelerate the alkali-silica reaction in mortars at 20 C.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20063731','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20063731"><span>[Vegetation influence on nutrients distribution in <span class="hlt">pore</span> <span class="hlt">water</span> of salt marsh sediment].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Wei-Wei; Li, Dao-Ji; Gao, Lei</p> <p>2009-11-01</p> <p>The variations of nutrients in <span class="hlt">pore</span> <span class="hlt">water</span> of salt marsh sediment were surveyed in the middle intertidal zone of Chongming Dongtan during August 2007 to May 2008 to identify plant impact on nutrients distribution. The results show that NH4(+) -N and PO4(3-) -P concentrations are lower in <span class="hlt">pore</span> <span class="hlt">water</span> of Spartina alterniflora and Phragmites australis zones than in bare flat, and specially, NH4(+) -N concentrations in summer and autumn decrease by one more orders of magnitude. Compared to winter, nutrients concentrations are obviously higher during the period of plant growth, and plant biomass is clearly correlative to nitrogen and phosphorus. Vegetation growth influences nitrogen content intensively. NH4(-) -N concentrations in Spartina alterniflora and Phragmites australis zones are 44.21 and 74.38 micromol x L(-1) respectively, distinctly lower than that in bare flat and Scirpus mariquete zone (340.14 and 291.87 micromol x L(-1) respectively). Moreover, NO(x)(-) -N concentration is one to two order(s) of magnitude lower than NH4(+) -N, and its highest value exists in Phragmites australis zone (5.94 micromol x L(-1)). The results of molecule diffusive flux of nutrients in the surface sediment-overlying <span class="hlt">water</span> interface indicate that marsh sediment is the source for SiO3(2-) -Si, NH4(+) -N and PO4(3-) -P, and the rank for NO(x)(-) -N (NO3(-) -N + NO2(-) -N), and NO(x)(-) -N flux from overlying <span class="hlt">water</span> to sediment [16.23 micromol x (m2 x h)(-1)] is higher than NH4(+) -N flux from sediment to overlying <span class="hlt">water</span> [15.53 micromol x (m2 x h)(-1)]. Vegetation growth accommodates nutrient structure of the estuarine ecosystem by affecting sediment-<span class="hlt">water</span> interface mass flux and nutrient ratios in <span class="hlt">pore</span> <span class="hlt">water</span> and overlying <span class="hlt">water</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70034971','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70034971"><span>Mercury cycling in stream ecosystems. 2. Benthic methylmercury production and bed sediment - <span class="hlt">Pore</span> <span class="hlt">water</span> partitioning</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Marvin-DiPasquale, M.; Lutz, M.A.; Brigham, M.E.; Krabbenhoft, D.P.; Aiken, G.R.; Orem, W.H.; Hall, B.D.</p> <p>2009-01-01</p> <p>Mercury speciation, controls on methylmercury (MeHg) production, and bed sediment - <span class="hlt">pore</span> <span class="hlt">water</span> partitioning of total Hg (THg) and MeHg were examined in bed sediment from eight geochemically diverse streams where atmospheric deposition was the predominant Hg input. Across all streams, sediment THg concentrations were best described as a combined function of sediment percent fines (%fines; particles < 63 ??m) and organic content. MeHg concentrations were best described as a combined function of organic content and the activity of the Hg(II)-methylating microbial community and were comparable to MeHg concentrations in streams with Hg inputs from industrial and mining sources. Whole sediment tin-reducible inorganic reactive Hg (Hg(II)R) was used as a proxy measure for the Hg(II) pool available for microbial methylation. In conjunction with radiotracer-derived rate constants of 203Hg(II) methylation, Hg(II)R was used to calculate MeHg production potential rates and to explain the spatial variability in MeHg concentration. The %Hg(II)R (of THg) was low (2.1 ?? 5.7%) and was inversely related to both microbial sulfate reduction rates and sediment total reduced sulfur concentration. While sediment THg concentrations were higher in urban streams, %MeHg and %Hg(II)R were higher in nonurban streams. Sediment <span class="hlt">pore</span> <span class="hlt">water</span> distribution coefficients (log Kd's) for both THg and MeHg were inversely related to the log-transformed ratio of <span class="hlt">pore</span> <span class="hlt">water</span> dissolved organic carbon (DOC) to bed sediment %fines. The stream with the highest drainage basin wetland density also had the highest <span class="hlt">pore</span> <span class="hlt">water</span> DOC ?? 2009 American Chemical Society.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70033063','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70033063"><span>Ecological impacts of lead mining on Ozark streams: Toxicity of sediment and <span class="hlt">pore</span> <span class="hlt">water</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Besser, J.M.; Brumbaugh, W.G.; Allert, A.L.; Poulton, B.C.; Schmitt, C.J.; Ingersoll, C.G.</p> <p>2009-01-01</p> <p>We studied the toxicity of sediments downstream of lead-zinc mining areas in southeast Missouri, using chronic sediment toxicity tests with the amphipod, Hyalella azteca, and <span class="hlt">pore-water</span> toxicity tests with the daphnid, Ceriodaphnia dubia. Tests conducted in 2002 documented reduced survival of amphipods in stream sediments collected near mining areas and reduced survival and reproduction of daphnids in most <span class="hlt">pore</span> <span class="hlt">waters</span> tested. Additional amphipod tests conducted in 2004 documented significant toxic effects of sediments from three streams downstream of mining areas: Strother Creek, West Fork Black River, and Bee Fork. Greatest toxicity occurred in sediments from a 6-km reach of upper Strother Creek, but significant toxic effects occurred in sediments collected at least 14 km downstream of mining in all three watersheds. Toxic effects were significantly correlated with metal concentrations (nickel, zinc, cadmium, and lead) in sediments and <span class="hlt">pore</span> <span class="hlt">waters</span> and were generally consistent with predictions of metal toxicity risks based on sediment quality guidelines, although ammonia and manganese may also have contributed to toxicity at a few sites. Responses of amphipods in sediment toxicity tests were significantly correlated with characteristics of benthic invertebrate communities in study streams. These results indicate that toxicity of metals associated with sediments contributes to adverse ecological effects in streams draining the Viburnum Trend mining district.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMNH51D1932K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMNH51D1932K"><span>Characteristics of fluoride in <span class="hlt">pore-water</span> at accidental hydrofluoric acid spillage site, Gumi, Korea</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kwon, E. H.; Lee, H. A.; Lee, J.; Kim, D.; Lee, S.; Yoon, H. O.</p> <p>2015-12-01</p> <p>A leakage accident of hydrofluoric acid (HF) occurred in Gumi, South Korea at Sep. 2012. The study site is located in the borderline between a large-scale industrial complex and a rural area. The HF plume was made immediately, and moved toward the rural area through air. After the accident, 212 ha of farm land were influenced and most of crops were withered. To recover the soil, CaO was applied after six months. Although several studies have done to estimate the extension and movement of HF plume in the air and to assess the impact on human health or plant after the incident, the long-term fate of fluoride (F) in the affected soils is not identified clearly. Thus, this study aimed to understand the behavior of F in the soil after HF releasing from accident site through chemical analysis and geochemical modeling. Within the radius of 1 km of accident site, 16 <span class="hlt">pore-water</span> and soil samples were collected. The semi-quantitative soil composition (i.e., Al, Ca, Fe, K, Mg, Mn, Na, P, Si, Ti), total F, total P, OM contents in soil, and soil pH have already been measured, and <span class="hlt">pore-water</span> compositions are also identified. From these experimental and modeling data, we could be evaluate if impact of accident exists until now, and also could be select and identify existing form of fluoride in soil and <span class="hlt">pore-water</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70032530','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70032530"><span>Mapping of accumulated nitrogen in the sediment <span class="hlt">pore</span> <span class="hlt">water</span> of a eutrophic lake in Iowa, USA</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Iqbal, M.Z.; Fields, C.L.</p> <p>2009-01-01</p> <p>A large pool of nitrogen in the sediment <span class="hlt">pore</span> fluid of a eutrophic lake in Iowa, USA, was mapped in this study. Previously, the lake had supported fishing and boating, but today it no longer supports its designated uses as a recreational <span class="hlt">water</span> body. In the top 5 cm of the lake bottom, the <span class="hlt">pore</span> <span class="hlt">water</span> nitrogen ranges between 3.1 and 1,250 ??g/cm3 of sediments, with an average of 160.3 ??g/cm3. Vertically, nitrate concentrations were measured as 153 ??g/cm3 at 0-10 cm, 162 ??g/cm3 at 10-20 cm, and 32 ??g/cm3 at 20-30 cm. Nitrate mass distribution was quantified as 3.67 ?? 103 kg (65%) in the bottom sediments, 172 kg (3%) in suspended particulates, and 1.83 ?? 103 kg (32%) in the dissolved phase. Soil runoff nutrients arrive at the lake from the heavily fertilized lands in the watershed. Upon sedimentation, a large mass of nitrogen desorbs from mineral particles to the relatively immobile <span class="hlt">pore</span> fluid. Under favorable conditions, this nitrogen diffuses back into the <span class="hlt">water</span> column, thereby dramatically limiting the lake's capability to process incoming nutrients from farmlands. Consequently, a condition of oxygen deficiency disrupts the post-season biological activities in the lake. ?? 2008 Springer-Verlag.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1007760','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1007760"><span>Development of Layered Sediment Structure and its Effects on <span class="hlt">Pore</span> <span class="hlt">Water</span> Transport and Hyporheic Exchange</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Packman, Aaron I.; Marion, Andrea; Zaramella, Mattia; Chen, Cheng; Gaillard, Jean-François; Keane, Denis T.</p> <p>2008-04-15</p> <p>Hyporheic exchange is known to provide an important control on nutrient and contaminant fluxes across the stream-subsurface interface. Similar processes also mediate interfacial transport in other permeable sediments. Recent research has focused on understanding the mechanics of these exchange processes and improving estimation of exchange rates in natural systems. While the structure of sediment beds obviously influences <span class="hlt">pore</span> <span class="hlt">water</span> flow rates and patterns, little is known about the interplay of typical sedimentary structures, hyporheic exchange, and other transport processes in fluvial/alluvial sediments. Here we discuss several processes that contribute to local-scale sediment heterogeneity and present results that illustrate the interaction of overlying flow conditions, the development of sediment structure, <span class="hlt">pore</span> <span class="hlt">water</span> transport, and stream-subsurface exchange. Layered structures are shown to develop at several scales within sediment beds. Surface sampling is used to analyze the development of an armor layer in a sand-and-gravel bed, while innovative synchrotron-based X-ray microtomography is used to observe patterns of grain sorting within sand bedforms. We show that layered bed structures involving coarsening of the bed surface increase interfacial solute flux but produce an effective anisotropy that favors horizontal <span class="hlt">pore</span> <span class="hlt">water</span> transport while limiting vertical penetration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1105044','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1105044"><span><span class="hlt">Pore</span> <span class="hlt">Water</span> Extraction Test Near 241-SX Tank Farm at the Hanford Site, Washington, USA</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Eberlein, Susan J.; Parker, Danny L.; Tabor, Cynthia L.; Holm, Melissa J.</p> <p>2013-11-11</p> <p>A proof-of-principle test is underway near the Hanford Site 241-SX Tank Farm. The test will evaluate a potential remediation technology that will use tank farm-deployable equipment to remove contaminated <span class="hlt">pore</span> <span class="hlt">water</span> from vadose zone soils. The test system was designed and built to address the constraints of working within a tank farm. Due to radioactive soil contamination and limitations in drilling near tanks, small-diameter direct push drilling techniques applicable to tank farms are being utilized for well placement. To address space and weight limitations in working around tanks and obstacles within tank farms, the above ground portions of the test system have been constructed to allow deployment flexibility. The test system utilizes low vacuum over a sealed well screen to establish flow into an extraction well. Extracted <span class="hlt">pore</span> <span class="hlt">water</span> is collected in a well sump,and then pumped to the surface using a small-diameter bladder pump.If <span class="hlt">pore</span> <span class="hlt">water</span> extraction using this system can be successfully demonstrated, it may be possible to target local contamination in the vadose zone around underground storage tanks. It is anticipated that the results of this proof-of-principle test will support future decision making regarding interim and final actions for soil contamination within the tank farms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013HESSD..1013293V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013HESSD..1013293V"><span>Continual in-situ monitoring of <span class="hlt">pore</span> <span class="hlt">water</span> stable isotopes in the subsurface</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Volkmann, T. H. M.; Weiler, M.</p> <p>2013-11-01</p> <p>The stable isotope signature of <span class="hlt">pore</span> <span class="hlt">water</span> provides an integral fingerprint of <span class="hlt">water</span> origin, flow path, transport processes, and residence times and can thus serve as a powerful tracer of hydrological processes in the unsaturated and saturated zone. However, the full potential of stable isotopes to quantitatively characterize subsurface <span class="hlt">water</span> dynamics is yet unfolded due to the difficulty in obtaining extensive detailed and continual measurements of spatiotemporally variable <span class="hlt">pore</span> <span class="hlt">water</span> signatures. With the development of field-deployable laser-based isotope analyzers, such measurements are now becoming feasible. This study presents the development and application of a functional, automatable, and cost-efficient system for non-destructive continual in-situ monitoring of <span class="hlt">pore</span> <span class="hlt">water</span> stable isotope signatures with high resolution. The monitoring system uses automatic-controllable valve arrays to continuously extract diluted soil air <span class="hlt">water</span> vapor via a branching network of multiple small microporous probes into a commercial isotope analyzer. Soil temperature observations are used to convert obtained vapor phase into liquid phase <span class="hlt">water</span> isotope signatures, but these can also be obtained based on vapor concentration measurements. In-situ sampling was conducted at six depths for each of three plots planted with varying vegetation on an experimental site in SW Germany. Two different methods based on advective and diffusive soil <span class="hlt">water</span> vapor probing were employed suitable under unsaturated and all (including saturated) moisture conditions, respectively. The advective sampling method was applied using multiple permanently installed probes (continual mode) and using a single probe subsequently inserted to sample the various locations (push-in mode), while the diffusive sampling method was applied in push-in mode only. Using a specific identical treatment onsite calibration approach along with basic corrections for instrument bias and temperature dependent free <span class="hlt">water</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMNH31B1602B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMNH31B1602B"><span>Elucidating the mechanical effects of <span class="hlt">pore</span> <span class="hlt">water</span> pressure increase on the stability of unsaturated soil slopes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Buscarnera, G.</p> <p>2012-12-01</p> <p>The increase of the <span class="hlt">pore</span> <span class="hlt">water</span> pressure due to rain infiltration can be a dominant component in the activation of slope failures. This paper shows an application of the theory of material stability to the triggering analysis of this important class of natural hazards. The goal is to identify the mechanisms through which the process of suction removal promotes the initiation of mechanical instabilities. The interplay between increase in <span class="hlt">pore</span> <span class="hlt">water</span> pressure, and failure mechanisms is investigated at material point level. In order to account for multiple failure mechanisms, the second-order work criterion is used and different stability indices are devised. The paper shows that the theory of material stability can assess the risk of shear failure and static liquefaction in both saturated and unsaturated contexts. It is shown that the combined use of an enhanced definition of second-order work for unsaturated porous media and a hydro-mechanical constitutive framework enables to retrieve bifurcation conditions for <span class="hlt">water</span>-infiltration processes in unsaturated deposits. This finding discloses the importance of the coupling terms that incorporate the interaction between the solid skeleton and the <span class="hlt">pore</span> fluids. As a consequence, these theoretical results suggest that some material properties that are not directly associated with the shearing resistance (e.g., the potential for wetting compaction) can play an important role in the initiation of slope failures. According to the proposed interpretation, the process of <span class="hlt">pore</span> pressure increase can be understood as a trigger of uncontrolled strains, which at material point level are reflected by the onset of bifurcation conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28297654','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28297654"><span>Role of <span class="hlt">Pore</span>-Lining Residues in Defining the Rate of <span class="hlt">Water</span> Conduction by Aquaporin-0.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Saboe, Patrick O; Rapisarda, Chiara; Kaptan, Shreyas; Hsiao, Yu-Shan; Summers, Samantha R; De Zorzi, Rita; Dukovski, Danijela; Yu, Jiaheng; de Groot, Bert L; Kumar, Manish; Walz, Thomas</p> <p>2017-03-14</p> <p>Compared to other aquaporins (AQPs), lens-specific AQP0 is a poor <span class="hlt">water</span> channel, and its permeability was reported to be pH-dependent. To date, most <span class="hlt">water</span> conduction studies on AQP0 were performed on protein expressed in Xenopus oocytes, and the results may therefore also reflect effects introduced by the oocytes themselves. Experiments with purified AQP0 reconstituted into liposomes are challenging because the <span class="hlt">water</span> permeability of AQP0 is only slightly higher than that of pure lipid bilayers. By reconstituting high amounts of AQP0 and using high concentrations of cholesterol to reduce the permeability of the lipid bilayer, we improved the signal-to-noise ratio of <span class="hlt">water</span> permeability measurements on AQP0 proteoliposomes. Our measurements show that mutation of two <span class="hlt">pore</span>-lining tyrosine residues, Tyr-23 and Tyr-149 in sheep AQP0, to the corresponding residues in the high-permeability <span class="hlt">water</span> channel AQP1 have additive effects and together increase the <span class="hlt">water</span> permeability of AQP0 40-fold to a level comparable to that of AQP1. Molecular dynamics simulations qualitatively support these experimental findings and suggest that mutation of Tyr-23 changes the <span class="hlt">pore</span> profile at the gate formed by residue Arg-187.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12463685','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12463685"><span>A <span class="hlt">marine</span> bioassay test set to assess <span class="hlt">marine</span> <span class="hlt">water</span> and sediment quality-its need, the approach and first results.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Peters, C; Becker, S; Noack, U; Pfitzner, S; Bülow, W; Barz, K; Ahlf, W; Berghahn, R</p> <p>2002-10-01</p> <p>There is a need for establishing a <span class="hlt">marine</span> bioassay test set to assess <span class="hlt">marine</span> <span class="hlt">water</span> and sediment samples in Germany. The selected <span class="hlt">marine</span> bioassay test set, two tests for the <span class="hlt">water</span> phase (with the luminescence bacteria Vibrio fischeri and the algae Phaeodactylum tricornutum Bohlin) and a whole sediment test with the <span class="hlt">marine</span> amphipod Corophium volutator (Pallas) is described and first results are shown.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16794088','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16794088"><span>Is hot <span class="hlt">water</span> immersion an effective treatment for <span class="hlt">marine</span> envenomation?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Atkinson, P R T; Boyle, A; Hartin, D; McAuley, D</p> <p>2006-07-01</p> <p>Envenomation by <span class="hlt">marine</span> creatures is common. As more people dive and snorkel for leisure, the incidence of envenomation injuries presenting to emergency departments has increased. Although most serious envenomations occur in the temperate or tropical <span class="hlt">waters</span> of the Indo-Pacific region, North American and European <span class="hlt">waters</span> also provide a habitat for many stinging creatures. <span class="hlt">Marine</span> envenomations can be classified as either surface stings or puncture wounds. Antivenom is available for a limited number of specific <span class="hlt">marine</span> creatures. Various other treatments such as vinegar, fig juice, boiled cactus, heated stones, hot urine, hot <span class="hlt">water</span>, and ice have been proposed, although many have little scientific basis. The use of heat therapies, previously reserved for penetrating fish spine injuries, has been suggested as treatment for an increasing variety of <span class="hlt">marine</span> envenomation. This paper reviews the evidence for the effectiveness of hot <span class="hlt">water</span> immersion (HWI) and other heat therapies in the management of patients presenting with pain due to <span class="hlt">marine</span> envenomation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/20871542','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/20871542"><span>Inkbottle <span class="hlt">Pore</span>-Method: Prediction of hygroscopic <span class="hlt">water</span> content in hardened cement paste at variable climatic conditions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Espinosa, Rosa Maria . E-mail: espinosa@tuhh.de; Franke, Lutz</p> <p>2006-10-15</p> <p>The aim of this work is the development of a practicable method for the reliable prediction of the equilibrium hygroscopic <span class="hlt">water</span> content in hardened cement paste and cement mortars at changing climatic conditions. Sorption thermodynamics and multi-scale <span class="hlt">pore</span> structure of hardened cement paste build the basis of the new computation procedure. Drying and chemical aging lead to a formation of inkbottle <span class="hlt">pores</span>. Their influence on sorption behaviour will be considered in particular by including them into the <span class="hlt">pore</span> model. Experimental data of adsorption, desorption and scanning-isotherms verify the new computation method, which has been called 'IBP-Method' (inkbottle <span class="hlt">pores</span>)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/893390','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/893390"><span>Data Qualification Report: <span class="hlt">Pore</span> <span class="hlt">Water</span> Data for Use on the Yucca Mountain Project</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>H. Miller; R. Monks; C. Warren; W. Wowak</p> <p>2000-06-09</p> <p><span class="hlt">Pore</span> <span class="hlt">water</span> data associated with Data Tracking Number (DTN) No.LL990702804244.100 are referenced in the Analysis and Model Reports (AMRs) prepared to support the Site Recommendation in determining the suitability of the Yucca Mountain, Nevada as a repository for high-level nuclear waste. It has been determined, in accordance with procedure AP-3.15Q Rev. 1, ICN 1, ''Managing Technical Product Inputs'', Attachment 6 , that the DTN-referenced data are used in AMRs that provide a direct calculation of ''Principal Factors'' for the Post-closure Safety Case or Potentially Disruptive Processes or Events. Therefore, in accordance with the requirements of procedure AP-SIII.2Q, Rev 0, ICN 2, ''Qualification of Unqualified Data and the Documentation of Rationale for Accepted Data'', Section 5.3.1 .a, a Data Qualification Report has been prepared for submittal to the Assistant Manager, Office of Project Execution for concurrence. This report summarizes the findings of the Data Qualification Team assembled to evaluate unqualified ''<span class="hlt">pore</span> <span class="hlt">water</span> data'' represented by DTN No. LL990702804244.100. This DTN is currently used in the following AMRs: Drift-Scale Coupled Processes (DST and THC Seepage) Models (CRWMS M&O 2000a), Environment of the Surfaces of the Drip Shield and Waste Package Outer Barrier (CRWMS M&O 2000b), and Engineered Barrier System: Physical and Chemical Environment Model (CRWMS M&O 2000c). Mineral composition of <span class="hlt">pore</span> <span class="hlt">water</span> submitted to the Technical Data Management System (TDMS) using the subject DTN were acquired data from the analysis <span class="hlt">pore</span> <span class="hlt">water</span> samples sent to Lawrence Livermore National Laboratory's (LLNL) by UFA Ventures, Inc. and analyzed by LLNL's Analytical Sciences/Analytical and Nuclear Chemistry Division (ASD). The purpose and scope of the AMRs that reference the subject DTN and the potential application of <span class="hlt">pore</span> <span class="hlt">water</span> data is described below. These AMRs use only that data associated with the specific samples: ESF-HD-PERM-1, ESF-HD-PERM-2, and ESF-HD-PERM-3</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1343742-linking-basin-scale-pore-scale-gas-hydrate-distribution-patterns-diffusion-dominated-marine-hydrate-systems','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1343742-linking-basin-scale-pore-scale-gas-hydrate-distribution-patterns-diffusion-dominated-marine-hydrate-systems"><span>Linking basin-scale and <span class="hlt">pore</span>-scale gas hydrate distribution patterns in diffusion-dominated <span class="hlt">marine</span> hydrate systems</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Nole, Michael; Daigle, Hugh; Cook, Ann E.; ...</p> <p>2017-02-07</p> <p>The goal of this study is to computationally determine the potential distribution patterns of diffusion-driven methane hydrate accumulations in coarse-grained <span class="hlt">marine</span> sediments. Diffusion of dissolved methane in <span class="hlt">marine</span> gas hydrate systems has been proposed as a potential transport mechanism through which large concentrations of hydrate can preferentially accumulate in coarse-grained sediments over geologic time. Using one-dimensional compositional reservoir simulations, we examine hydrate distribution patterns at the scale of individual sand layers (1 to 20 m thick) that are deposited between microbially active fine-grained material buried through the gas hydrate stability zone (GHSZ). We then extrapolate to two- dimensional and basin-scalemore » three-dimensional simulations, where we model dipping sands and multilayered systems. We find that properties of a sand layer including <span class="hlt">pore</span> size distribution, layer thickness, dip, and proximity to other layers in multilayered systems all exert control on diffusive methane fluxes toward and within a sand, which in turn impact the distribution of hydrate throughout a sand unit. In all of these simulations, we incorporate data on physical properties and sand layer geometries from the Terrebonne Basin gas hydrate system in the Gulf of Mexico. We demonstrate that diffusion can generate high hydrate saturations (upward of 90%) at the edges of thin sands at shallow depths within the GHSZ, but that it is ineffective at producing high hydrate saturations throughout thick (greater than 10 m) sands buried deep within the GHSZ. As a result, we find that hydrate in fine-grained material can preserve high hydrate saturations in nearby thin sands with burial.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1226245','SCIGOV-DOEDE'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1226245"><span>Surface and Active Layer <span class="hlt">Pore</span> <span class="hlt">Water</span> Chemistry from Ice Wedge Polygons, Barrow, Alaska, 2013-2014</span></a></p> <p><a target="_blank" href="http://www.osti.gov/dataexplorer">DOE Data Explorer</a></p> <p>David E. Graham; Baohua Gu; Elizabeth M. Herndon; Stan D. Wullschleger; Ziming Yang; Liyuan Liang</p> <p>2016-11-10</p> <p>This data set reports the results of spatial surveys of aqueous geochemistry conducted at Intensive Site 1 of the Barrow Environmental Observatory in 2013 and 2014 (Herndon et al., 2015). Surface <span class="hlt">water</span> and soil <span class="hlt">pore</span> <span class="hlt">water</span> samples were collected from multiple depths within the tundra active layer of different microtopographic features (troughs, ridges, center) of a low-centered polygon (area A), high-centered polygon (area B), flat-centered polygon (area C), and transitional polygon (area D). Reported analytes include dissolved organic and inorganic carbon, dissolved carbon dioxide and methane, major inorganic anions, and major and minor cations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPhCS.618a2041S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPhCS.618a2041S"><span>Confined <span class="hlt">water</span> in controlled <span class="hlt">pore</span> glass CPG-10-120 studied by positron annihilation lifetime spectroscopy and differential scanning calorimetry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Šauša, O.; Mat'ko, I.; Illeková, E.; Macová, E.; Berek, D.</p> <p>2015-06-01</p> <p>The solidification and melting of <span class="hlt">water</span> confined in the controlled <span class="hlt">pore</span> glass (CPG) with average <span class="hlt">pore</span> size 12.6 nm has been studied by differential scanning calorimetry (DSC) and positron annihilation lifetime spectroscopy (PALS). The fully-filled sample of CPG by <span class="hlt">water</span> as well as the samples of CPG with different content of <span class="hlt">water</span> were used. The measurements show the presence of amorphous and crystalline phases of <span class="hlt">water</span> in this type and size of <span class="hlt">pores</span>, freezing point depression of a confined liquid and presence of certain transitions at lower temperatures, which could be detected only for cooling regime. The localization of confined <span class="hlt">water</span> in the partially filled <span class="hlt">pores</span> of CPG at room temperature was studied.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1301716','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1301716"><span>Insertion and <span class="hlt">pore</span> formation driven by adsorption of proteins onto lipid bilayer membrane-<span class="hlt">water</span> interfaces.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zuckermann, M J; Heimburg, T</p> <p>2001-01-01</p> <p>We describe the binding of proteins to lipid bilayers in the case for which binding can occur either by adsorption to the lipid bilayer membrane-<span class="hlt">water</span> interface or by direct insertion into the bilayer itself. We examine in particular the case when the insertion and <span class="hlt">pore</span> formation are driven by the adsorption process using scaled particle theory. The adsorbed proteins form a two-dimensional "surface gas" at the lipid bilayer membrane-<span class="hlt">water</span> interface that exerts a lateral pressure on the lipid bilayer membrane. Under conditions of strong intrinsic binding and a high degree of interfacial converge, this pressure can become high enough to overcome the energy barrier for protein insertion. Under these conditions, a subtle equilibrium exists between the adsorbed and inserted proteins. We propose that this provides a control mechanism for reversible insertion and <span class="hlt">pore</span> formation of proteins such as melittin and magainin. Next, we discuss experimental data for the binding isotherms of cytochrome c to charged lipid membranes in the light of our theory and predict that cytochrome c inserts into charged lipid bilayers at low ionic strength. This prediction is supported by titration calorimetry results that are reported here. We were furthermore able to describe the observed binding isotherms of the <span class="hlt">pore</span>-forming peptides endotoxin (alpha 5-helix) and of pardaxin to zwitterionic vesicles from our theory by assuming adsorption/insertion equilibrium. PMID:11606262</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.3878U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.3878U"><span>Simulated Seismic Load Tests on Dam Core Material to Scrutinize <span class="hlt">Pore</span> <span class="hlt">Water</span> Pressure Development</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Umar Farooq, Qazi; Uchimura, Taro</p> <p>2010-05-01</p> <p>Dam Core is the back bone of the large earthen dam and primarily constructed with fine grained soils. In this research Cyclic tri-axial tests are used to simulate the effect of different earthquake intensities on medium to high confined Fujinomori clay (replicated dam core material). Seismic load intensity is reproduced in the laboratory by applying different cyclic stress amplitudes, while the numbers of cycles (N) were kept constant. Both isotropic and anisotropic conditions are included in the test plan. Key discussions are distresses generated by seismic loading such as <span class="hlt">pore</span> <span class="hlt">water</span> pressure (PWP), deformations, possibility of micro cracking, and effective strength reduction. With increase in cyclic stress amplitude, exponential increases in <span class="hlt">pore</span> pressure (PWP), sudden decrease in mean effective principal stress (P') which ultimately increases overall instability in dam core, large deformations, and generation of micro / macro cracking are primary conclusions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70046045','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70046045"><span>A USANS/SANS study of the accessibility of <span class="hlt">pores</span> in the Barnett Shale to methane and <span class="hlt">water</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ruppert, Leslie F.; Sakurovs, Richard; Blach, Tomasz P.; He, Lilin; Melnichenko, Yuri B.; Mildner, David F.; Alcantar-Lopez, Leo</p> <p>2013-01-01</p> <p>Shale is an increasingly important source of natural gas in the United States. The gas is held in fine <span class="hlt">pores</span> that need to be accessed by horizontal drilling and hydrofracturing techniques. Understanding the nature of the <span class="hlt">pores</span> may provide clues to making gas extraction more efficient. We have investigated two Mississippian Barnett Shale samples, combining small-angle neutron scattering (SANS) and ultrasmall-angle neutron scattering (USANS) to determine the <span class="hlt">pore</span> size distribution of the shale over the size range 10 nm to 10 μm. By adding deuterated methane (CD4) and, separately, deuterated <span class="hlt">water</span> (D2O) to the shale, we have identified the fraction of <span class="hlt">pores</span> that are accessible to these compounds over this size range. The total <span class="hlt">pore</span> size distribution is essentially identical for the two samples. At <span class="hlt">pore</span> sizes >250 nm, >85% of the <span class="hlt">pores</span> in both samples are accessible to both CD4 and D2O. However, differences in accessibility to CD4 are observed in the smaller <span class="hlt">pore</span> sizes (~25 nm). In one sample, CD4 penetrated the smallest <span class="hlt">pores</span> as effectively as it did the larger ones. In the other sample, less than 70% of the smallest <span class="hlt">pores</span> (4, but they were still largely penetrable by <span class="hlt">water</span>, suggesting that small-scale heterogeneities in methane accessibility occur in the shale samples even though the total porosity does not differ. An additional study investigating the dependence of scattered intensity with pressure of CD4 allows for an accurate estimation of the pressure at which the scattered intensity is at a minimum. This study provides information about the composition of the material immediately surrounding the <span class="hlt">pores</span>. Most of the accessible (open) <span class="hlt">pores</span> in the 25 nm size range can be associated with either mineral matter or high reflectance organic material. However, a complementary scanning electron microscopy investigation shows that most of the <span class="hlt">pores</span> in these shale samples are contained in the organic components. The neutron scattering results indicate that the <span class="hlt">pores</span> are</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/860281','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/860281"><span>STRONTIUM ISOTOPE EVOLUTION OF <span class="hlt">PORE</span> <span class="hlt">WATER</span> AND CALCITE IN THE TOPOPAH SPRING TUFF, YUCCA MOUNTAIN , NEVADA</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>B.D. Marshall; K. Futa</p> <p>2001-02-07</p> <p>Yucca Mountain, a ridge of Miocene volcanic rocks in southwest Nevada, is being characterized as a site for a potential high-level radioactive waste repository. One issue of concern for the future performance of the potential repository is the movement of <span class="hlt">water</span> in and around the potential repository horizon. Past <span class="hlt">water</span> movement in this unsaturated zone is indicated by fluid inclusions trapped in calcite coatings on fracture footwall surfaces and in some lithophysal cavities. Some of the fluid inclusions have homogenization temperatures above the present-day geotherm (J.F. Whelan, written communication), so determining the ages of the calcite associated with those fluid inclusions is important in understanding the thermal history of the potential repository site. Calcite ages have been constrained by uranium-lead dating of silica polymorphs (opal and chalcedony) that are present in most coatings. The opal and chalcedony ages indicate that deposition of the calcite and opal coatings in the welded part of the Topopah Spring Tuff (TSw hydrogeologic unit) spanned nearly the entire history of the 12.8-million-year-old rock mass at fairly uniform overall long-term rates of deposition (within a factor of five). Constraining the age of a layer of calcite associated with specific fluid inclusions is complicated. Calcite is commonly bladed with complex textural relations, and datable opal or chalcedony may be millions of years older or younger than the calcite layer or may be absent from the coating entirely. Therefore, a more direct method of dating the calcite is presented in this paper by developing a model for strontium evolution in <span class="hlt">pore</span> <span class="hlt">water</span> in the TSw as recorded by the strontium coprecipitated with calcium in the calcite. Although the <span class="hlt">water</span> that precipitated the calcite in fractures and cavities may not have been in local isotopic equilibrium with the <span class="hlt">pore</span> <span class="hlt">water</span>, the strontium isotope composition of all <span class="hlt">water</span> in the TSw is primarily controlled by <span class="hlt">water</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22037694','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22037694"><span>Transgenic nematodes as biosensors for metal stress in soil <span class="hlt">pore</span> <span class="hlt">water</span> samples.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Anbalagan, Charumathi; Lafayette, Ivan; Antoniou-Kourounioti, Melissa; Haque, Mainul; King, John; Johnsen, Bob; Baillie, David; Gutierrez, Carmen; Martin, Jose A Rodriguez; de Pomerai, David</p> <p>2012-03-01</p> <p>Caenorhabditis elegans strains carrying stress-reporter green fluorescent protein transgenes were used to explore patterns of response to metals. Multiple stress pathways were induced at high doses by most metals tested, including members of the heat shock, oxidative stress, metallothionein (mtl) and xenobiotic response gene families. A mathematical model (to be published separately) of the gene regulatory circuit controlling mtl production predicted that chemically similar divalent metals (classic inducers) should show additive effects on mtl gene induction, whereas chemically dissimilar metals should show interference. These predictions were verified experimentally; thus cadmium and mercury showed additive effects, whereas ferric iron (a weak inducer) significantly reduced the effect of mercury. We applied a similar battery of tests to diluted samples of soil <span class="hlt">pore</span> <span class="hlt">water</span> extracted centrifugally after mixing 20% w/w ultrapure <span class="hlt">water</span> with air-dried soil from an abandoned lead/zinc mine in the Murcia region of Spain. In addition, metal contents of both soil and soil <span class="hlt">pore</span> <span class="hlt">water</span> were determined by ICP-MS, and simplified mixtures of soluble metal salts were tested at equivalent final concentrations. The effects of extracted soil <span class="hlt">pore</span> <span class="hlt">water</span> (after tenfold dilution) were closely mimicked by mixtures of its principal component ions, and even by the single most prevalent contaminant (zinc) alone, though other metals modulated its effects both positively and negatively. In general, mixtures containing similar (divalent) metal ions exhibited mainly additive effects, whereas admixture of dissimilar (e.g. trivalent) ions often resulted in interference, reducing overall levels of stress-gene induction. These findings were also consistent with model predictions.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ApSS..283..941L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ApSS..283..941L"><span>Effects of residual <span class="hlt">water</span> in the <span class="hlt">pores</span> of aluminum anodic oxide layers prior to sealing on corrosion resistance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Junghoon; Jung, Uoochang; Kim, Wangryeol; Chung, Wonsub</p> <p>2013-10-01</p> <p>The effects of residual <span class="hlt">water</span> in the <span class="hlt">pores</span> of aluminum anodic oxide layers before the sealing process on corrosion resistance were studied. When residual <span class="hlt">water</span> was present in <span class="hlt">pores</span> before cold NiF2 sealing, corrosion resistance was dramatically increased especially in acid chloride electrolyte. It is considered that residual <span class="hlt">water</span> in <span class="hlt">pores</span> provides paths that allow sealing media to diffuse through the oxide layer, thereby sealing <span class="hlt">pores</span> up to inner side of porous layer nearby barrier layer. For hydrothermal sealing, corrosion resistance improvements by residual <span class="hlt">water</span> were also observed. However, improvements in corrosion resistance by cold NiF2 sealing were greater than those achieved by hydrothermal sealing, due to cracks formation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009PhRvE..79c1606M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009PhRvE..79c1606M"><span>Molecular dynamics simulations of supercritical <span class="hlt">water</span> confined within a carbon-slit <span class="hlt">pore</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Martí, J.; Sala, J.; Guàrdia, E.; Gordillo, M. C.</p> <p>2009-03-01</p> <p>We report the results of a series of molecular dynamics simulations of <span class="hlt">water</span> inside a carbon-slit <span class="hlt">pore</span> at supercritical conditions. A range of densities corresponding from liquid (0.66gcm-3) to gas environments (0.08gcm-3) at the supercritical temperature of 673K were considered. Our findings are compared with previous studies of liquid <span class="hlt">water</span> confined in graphene nanochannels at ambient and high temperatures, and indicate that the microscopic structure of <span class="hlt">water</span> evolves from hydrogen bond networks characteristic of hot dense liquids to looser arrangements where the dominant units are <span class="hlt">water</span> monomers and dimers. <span class="hlt">Water</span> permittivity was found to be very small at low densities, with a tendency to grow with density and to reach typical values of unconfined supercritical <span class="hlt">water</span> at 0.66gcm-3) . In supercritical conditions, the residence time of <span class="hlt">water</span> at interfaces is roughly similar to that of <span class="hlt">water</span> in the central regions of the slabs, if the size of the considered region is taken into account. That time span is long enough to compute dynamical properties such as diffusion or spectral densities. <span class="hlt">Water</span> diffusion in supercritical states is much faster at low densities, and it is produced in such a way that, at interfaces, translational diffusion is mainly produced along planes parallel to the carbon walls. Spectral frequency shifts depend on several factors, being temperature and density effects the most relevant. However, we can observe corrections due to confinement, important both at the graphene interface and in the central region of the <span class="hlt">water</span> slab.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/20062609','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/20062609"><span>The radiocarbon age of calcite dissolving at the sea floor: Estimates from <span class="hlt">pore</span> <span class="hlt">water</span> data</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Martin, W.R.; McNichol, A.P.; McCorkle, D.C.</p> <p>2000-04-01</p> <p>The authors measured the radiocarbon content and stable isotopic composition of <span class="hlt">pore</span> <span class="hlt">water</span> and bottom <span class="hlt">water</span> {Sigma}CO{sub 2}, sedimentary organic carbon, and CaCO{sub 3} at two sites on the Ceara Rise, one underlying bottom <span class="hlt">water</span> that is supersaturated with respect to calcite (Site B), the other underlying under saturated bottom <span class="hlt">water</span> (Site G). The results were combined with <span class="hlt">pore</span> <span class="hlt">water</span> O{sub 2}, {Sigma}CO{sub 2}, and Ca{sup 2+} profiles (Martin and Sayles, 1996) to estimate the radiocarbon content of the CaCO{sub 3} that is dissolving in the sediment mixed layer. At Site G, the CaCO{sub 3} that is dissolving in the upper 2 cm of the sediments is clearly younger (richer in {sup 14}C) than the bulk sedimentary CaCO{sub 3}, indicating that nonhomogeneous CaCO{sub 3} dissolution occurs there. The case for nonhomogeneous dissolution is much weaker at the site underlying supersaturated bottom <span class="hlt">water</span>. The results indicate that nonhomogeneous dissolution occurs in sediments underlying under saturated bottom <span class="hlt">water</span>, that the dissolution is rapid relative to the rate of homogenization of the CaCO{sub 3} in the mixed layer by bioturbation, and that the dissolution rate of CaCO{sub 3} decreases as it ages in the sediment mixed layer. The results support the hypothesis, based on solid phase analyses, that the preferential dissolution of young (i.e., radiocarbon-rich) CaCO{sub 3} leads to a pattern of increasing radiocarbon age of mixed-layer CaCO{sub 3} as the degree of under saturation of bottom <span class="hlt">water</span> increases (Keir, 1984; Broecker et al., 1991).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://sofia.usgs.gov/publications/ofr/97-454/','USGSPUBS'); return false;" href="http://sofia.usgs.gov/publications/ofr/97-454/"><span>Geochemistry of surface and <span class="hlt">pore</span> <span class="hlt">water</span> at USGS coring sites in wetlands of South Florida, 1994 and 1995</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Orem, William H.; Lerch, Harry E.; Rawlik, Peter</p> <p>2002-01-01</p> <p>In this report, we present preliminary data on surface and <span class="hlt">pore</span> <span class="hlt">water</span> geochemistry from 22 sites in south Florida sampled during 1994 and 1995. These results are part of a larger study designed to evaluate the role of biogeochemical processes in sediments in the cycling of carbon, nitrogen, phosphorus, and sulfur in the south Florida ecosystem. The data are briefly discussed in regard to regional trends in the concentrations of chemical species, and general diagenetic processes in sediments. These results are part of a larger study designed to evaluate the role of biogeochemical processes in sediments in the cycling of carbon, nitrogen, phosphorus, and sulfur in the south Florida ecosystem. These elements play a crucial role in regulating organic sedimentation, nutrient dynamics, redox conditions, and the biogeochemistry of mercury in the threatened wetlands of south Florida. <span class="hlt">Pore</span> <span class="hlt">water</span> samples for chemical analyis were obtained using a piston corer/squeezer designed to avoid compression of the sediment and avoid oxidation and contamination of the <span class="hlt">pore</span> <span class="hlt">water</span> samples. Results show distinct regional trends in both surface <span class="hlt">water</span> and <span class="hlt">pore</span> <span class="hlt">water</span> geochemistry. Most chemical species in surface and <span class="hlt">pore</span> <span class="hlt">water</span> show peak concentrations in <span class="hlt">Water</span> Conservation Area 2A, with diminishing concentrations to the south and west into <span class="hlt">Water</span> Conservation Area 3A, and Everglades National Park. The largest differences observed were for phosphate and sulfide, with concentrations in <span class="hlt">pore</span> <span class="hlt">waters</span> in <span class="hlt">Water</span> Conservation Area 2A up to 500x higher than concentrations observed in freshwater marsh areas of <span class="hlt">Water</span> Conservation Area 3A and Everglades National Park. Sites near the Hillsboro Canal in <span class="hlt">Water</span> Conservation Area 2A are heavily contaminated with both phosphorus and sulfur. <span class="hlt">Pore</span> <span class="hlt">water</span> profiles for dissolved reactive phosphate suggest that recycling of phosphorus at these contaminated sites occurs primarily in the upper 20 cm of sediment. High levels of sulfide in <span class="hlt">pore</span> <span class="hlt">water</span> in <span class="hlt">Water</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24437854','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24437854"><span><span class="hlt">Marine</span> mammal audibility of selected shallow-<span class="hlt">water</span> survey sources.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>MacGillivray, Alexander O; Racca, Roberto; Li, Zizheng</p> <p>2014-01-01</p> <p>Most attention about the acoustic effects of <span class="hlt">marine</span> survey sound sources on <span class="hlt">marine</span> mammals has focused on airgun arrays, with other common sources receiving less scrutiny. Sound levels above hearing threshold (sensation levels) were modeled for six <span class="hlt">marine</span> mammal species and seven different survey sources in shallow <span class="hlt">water</span>. The model indicated that odontocetes were most likely to hear sounds from mid-frequency sources (fishery, communication, and hydrographic systems), mysticetes from low-frequency sources (sub-bottom profiler and airguns), and pinnipeds from both mid- and low-frequency sources. High-frequency sources (side-scan and multibeam) generated the lowest estimated sensation levels for all <span class="hlt">marine</span> mammal species groups.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFM.H21B0801F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.H21B0801F"><span>The Relationship of the Smectite-Illite Conversion to <span class="hlt">Pore</span> <span class="hlt">Water</span> Salinity Trends, Deep <span class="hlt">Water</span> Offshore Niger Delta</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fitts, T. G.; Summa, L. L.</p> <p>2002-12-01</p> <p>Petroleum exploration in the deepwater Niger Delta has produced an abundance of physical property data and geochemical information in the section from 500 to 4000m below the seafloor. These have improved our understanding of the links between diagenetic processes and changes in <span class="hlt">pore</span> fluid chemistry, and further suggest that smectite dehydration is not a major contributor to overpressure in the section. Literature data, coupled with new log, x-ray diffraction and surface area measurements, suggest that smectite and mixed-layer illite-smectite are major components of Miocene to Recent shales in key deep <span class="hlt">water</span> wells. The smectite-illite transformation is generally complete by 2000m bml, corresponding to 80-90 degrees C. Such high percentages of hydrated clays result in sediments with low shallow overburden stresses, permeabilities and thermal conductivities. Because of the large contribution of smectite interlayer <span class="hlt">water</span> to the total <span class="hlt">water</span> content, diagenetic alteration of smectite more strongly affects density and <span class="hlt">pore</span> fluid chemistry profiles here than in areas with less hydrated clay. Coincident with the conversion of smectite to illite, the total dissolved solids in the <span class="hlt">pore</span> <span class="hlt">waters</span> from several wells in the deepwater Niger Delta decrease from near seawater values at the sea floor to approximatly 10,000 ppm at 2000m bml. <span class="hlt">Pore</span> fluid composition estimates are derived primarily from log calculation of <span class="hlt">water</span> resistivity, with limited confirmation from pressure gradients in <span class="hlt">water</span> legs, and uncontaminated MDT fluid samples. There are two models that could account for the observed decrease in salinity with depth: freshwater incursion via long-distance lateral fluid flow through continuous aquifers, and release of interlayer <span class="hlt">water</span> from smectite during diagenesis. The available data suggest that release of interlayer <span class="hlt">water</span> is the most likely explanation for the salinity observations from deep <span class="hlt">water</span> Nigeria. Freshwater incursions are more likely on the shallow <span class="hlt">water</span> shelf</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25965160','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25965160"><span>Soil-<span class="hlt">pore</span> <span class="hlt">water</span> distribution of silver and gold engineered nanoparticles in undisturbed soils under unsaturated conditions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tavares, D S; Rodrigues, S M; Cruz, N; Carvalho, C; Teixeira, T; Carvalho, L; Duarte, A C; Trindade, T; Pereira, E; Römkens, P F A M</p> <p>2015-10-01</p> <p>Release of engineered nanoparticles (ENPs) to soil is well documented but little is known on the subsequent soil-<span class="hlt">pore</span> <span class="hlt">water</span> distribution of ENPs once present in soil. In this study, the availability and mobility of silver (Ag) and gold (Au) ENPs added to agricultural soils were assessed in two separate pot experiments. <span class="hlt">Pore</span> <span class="hlt">water</span> samples collected from pots from day 1 to 45 using porous (<0.17 μm) membrane samplers suggest that both Ag and Au are retained almost completely within 24 h with less than 13% of the total added amount present in <span class="hlt">pore</span> <span class="hlt">water</span> on day 1. UV-Vis and TEM results showed that AuENPs in <span class="hlt">pore</span> <span class="hlt">water</span> were present as both homoaggregates and heteroaggregates until day 3 after which the concentration in <span class="hlt">pore</span> <span class="hlt">water</span> was too low to detect the presence of aggregates. A close relation between the concentration of Au and Fe in <span class="hlt">pore</span> <span class="hlt">water</span> suggests that the short term solubility of Au is partly controlled by natural soil colloids. Results suggest that under normal aerated soil conditions the actual availability of Ag and AuENPs is low which is relevant in view of risk assessment even though the impact of environmental conditions and soil properties on the reactivity of ENPs (and/or large ENPs aggregates) retained in the solid matrix need to be addressed further.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GGG....17.2054P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GGG....17.2054P"><span><span class="hlt">Pore</span> <span class="hlt">water</span> chemistry reveals gradients in mineral transformation across a model basaltic hillslope</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pohlmann, Michael; Dontsova, Katerina; Root, Robert; Ruiz, Joaquin; Troch, Peter; Chorover, Jon</p> <p>2016-06-01</p> <p>The extent of weathering incongruency during soil formation from rock controls local carbon and nutrient cycling in ecosystems, as well as the evolution of hydrologic flow paths. Prior studies of basalt weathering, including those that have quantified the dynamics of well-mixed, bench-scale laboratory reactors or characterized the structure and integrated response of field systems, indicate a strong influence of system scale on weathering rate and trajectory. For example, integrated catchment response tends to produce lower weathering rates than do well mixed reactors, but the mechanisms underlying these disparities remain unclear. Here we present <span class="hlt">pore</span> <span class="hlt">water</span> geochemistry and physical sensor data gathered during two controlled rainfall-runoff events on a large-scale convergent model hillslope mantled with 1 m uniform depth of granular basaltic porous media. The dense sampler and sensor array (1488 samplers and sensors embedded in 330 m3 of basalt) showed that rainfall-induced dissolution of basaltic glass produced supersaturation of <span class="hlt">pore</span> <span class="hlt">waters</span> with respect to multiple secondary solids including allophane, gibbsite, ferrihydrite, birnessite and calcite. The spatial distribution of saturation state was heterogeneous, suggesting an accumulation of solutes leading to precipitation of secondary solids along hydrologic flow paths. Rapid dissolution of primary silicates was widespread throughout the entire hillslope, irrespective of up-gradient flowpath length. However, coherent spatial variations in solution chemistry and saturation indices were observed in depth profiles and between distinct topographic regions of the hillslope. Colloids (110-2000 nm) enriched in iron (Fe), aluminum (Al), and phosphorus (P) were mobile in soil <span class="hlt">pore</span> <span class="hlt">waters</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.4449F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.4449F"><span>Functions of biological soil crusts on central European inland dunes: <span class="hlt">Water</span> repellency and <span class="hlt">pore</span> clogging influence <span class="hlt">water</span> infiltration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fischer, Thomas; Spröte, Roland; Veste, Maik; Wiehe, Wolfgang; Lange, Philipp; Bens, Oliver; Raab, Thomas; Hüttl, Reinhard F.</p> <p>2010-05-01</p> <p>Biological soil crusts play a key role for hydrological processes in many open landscapes. They seal and stabilize the topsoil and promote surface run-off. Three crust types were identified on two inland dunes in Brandenburg, North-East Germany: A natural, active dune, located in a former military training area near Lieberose, and an artificial dune, which was constructed in 2001 and which serves as a study area for geo-ecological monitoring of flora and fauna from the forefield of an opencast-mine ("Neuer Lugteich"). Both dunes consisted of Quarternary, carbonate-free, siliceous sandy substrate. Utilization of the mineral substrate at early stages of microbiotic crust development was assessed using chlorophyll concentrations, scanning electron (SEM) and optical microscopy. <span class="hlt">Water</span> repellency indices, which are an indication of surface polarity and wettability, were measured using the ethanol/<span class="hlt">water</span> microinfiltrometer method, and steady state <span class="hlt">water</span> flow was determined on the dry crusts and after 0, 300, 600, 1200 and 1800 seconds of wetting, thus allowing to follow <span class="hlt">pore</span> clogging through swelling of extracellular polymeric substances (EPS). Chlorophyll concentrations indicated early stages of crust development at both sites. In crust type 1, dominating sand grains were physically stabilized in their contact zones by accumulated organic matter and by few filamentous cyanobacteria and filamentous green algae. The <span class="hlt">pore</span> space was defined by the mineral matrix only. In crust type 2, filamentous cyanobacteria and algae partially filled in the matrix <span class="hlt">pores</span> and enmeshed sand grains. In the dry sample, the <span class="hlt">pore</span> space was dominated by crust organisms but still micropore channels, which are known to increase <span class="hlt">water</span> infiltration, were left. Crust type 3 was characterized by intense growth of filamentous and coccoid algae and cyanobacteria, and by few mosses, which covered less than 5% of the surface. Crust organisms completely utilized the substrate and clogged the <span class="hlt">pores</span> between</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24360917','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24360917"><span>Polyethylene passive samplers to determine sediment-<span class="hlt">pore</span> <span class="hlt">water</span> distribution coefficients of persistent organic pollutants in five heavily contaminated dredged sediments.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Charrasse, Benoit; Tixier, Céline; Hennebert, Pierre; Doumenq, Pierre</p> <p>2014-02-15</p> <p><span class="hlt">Pore</span> concentration and partition coefficients of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were determined in sediments from five distinct contaminated sites in France (<span class="hlt">marine</span> harbour, rivers canals and highway sedimentation tank). The assessment of the risk caused by such micropollutants requires, in most cases, the measurement of their availability. To assess this availability, low density polyethylene (LDPE) membrane samplers were exposed to these sediments under constant and low-level agitation over a period of 46 days. Freely dissolved <span class="hlt">pore</span> <span class="hlt">water</span> contaminant concentrations were estimated from the concentration at equilibrium in the LDPE membrane. The depletion of contaminants in the sediments was monitored by the use of performance reference compounds (PRCs). Marked differences in freely dissolved PAH and PCB concentrations and resulting sediment-<span class="hlt">pore</span> <span class="hlt">water</span> partition coefficients between these five sediments were observed. Data set was tested onto different empirical and mechanistic models. As final findings, triple domain sorption (a total organic carbon, black carbon and oil phase model) could model PCB data successfully whereas the best fitting for PAH partitioning was obtained by Raoult's Law model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5875534','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5875534"><span>Upwelling of hydrothermal solutions through ridge flank sediments shown by <span class="hlt">pore</span> <span class="hlt">water</span> profiles</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Maris, C.R.P.; Bender, M.L.</p> <p>1982-05-07</p> <p>High calcium ion and low magnesium ion concentrations in sediment <span class="hlt">pore</span> <span class="hlt">waters</span> in cores from the Galapagos Mounds Hydrothermal Field on the flank of the Galapagos Spreading Center are believed to be due to a calcium-magnesium exchange reaction between circulating seawater and basement basalt. The nonlinearity of the calcium ions and magnesium ion gradients indicates that these discharging hydrothermal solutions on the ridge flank are upwelling at the rate of about 1 centimeter per year through the pelagic sediments of the Mounds Field and at about 20 centimeters per year through the hydrothermal mounds themselves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70024130','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70024130"><span>Sequestration of priority pollutant PAHs from sediment <span class="hlt">pore</span> <span class="hlt">water</span> employing semipermeable membrane devices</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Williamson, K.S.; Petty, J.D.; Huckins, J.N.; Lebo, J.A.; Kaiser, E.M.</p> <p>2002-01-01</p> <p>Semipermeable membrane devices (SPMDs) were employed to sample sediment <span class="hlt">pore</span> <span class="hlt">water</span> in static exposure studies under controlled laboratory conditions using (control pond and formulated) sediments fortified with 15 priority pollutant polycyclic aromatic hydrocarbons (PPPAHs). The sediment fortification level of 750 ng/g was selected on the basis of what might be detected in a sediment sample from a contaminated area. The sampling interval consisted of 0, 4, 7, 14, and 28 days for each study. The analytical methodologies, as well as the extraction and sample cleanup procedures used in the isolation, characterization, and quantitation of 15 PPPAHs at different fortification levels in SPMDs, <span class="hlt">water</span>, and sediment were reported previously (Williamson, M.S. Thesis, University of Missouri - Columbia, USA; Williamson et al., Chemosphere (This issue - PII: S0045-6535(02)00394-6)) and used for this project. Average (mean) extraction recoveries for each PPPAH congener in each matrix are reported and discussed. No procedural blank extracts (controls) were found to contain any PPPAH residues above the method quantitation limit, therefore, no matrix interferences were detected. The focus of this publication is to demonstrate the ability to sequester environmental contaminants, specifically PPPAHs, from sediment <span class="hlt">pore</span> <span class="hlt">water</span> using SPMDs and two different types of fortified sediment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1024084','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1024084"><span>Liquid CO2 Displacement of <span class="hlt">Water</span> in a Dual-Permeability <span class="hlt">Pore</span> Network Micromodel</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhang, Changyong; Oostrom, Martinus; Grate, Jay W.; Wietsma, Thomas W.; Warner, Marvin G.</p> <p>2011-09-01</p> <p>Permeability contrasts exist in multilayer geological formations under consideration for carbon sequestration. To improve our understanding of heterogeneous <span class="hlt">pore</span>-scale displacements, liquid CO2 (LCO2) - <span class="hlt">water</span> displacement was evaluated in a <span class="hlt">pore</span> network micromodel with two distinct permeability zones. Due to the low viscosity ratio (logM = -1.1), unstable displacement occurred at all injection rates over two orders of magnitude. LCO2 displaced <span class="hlt">water</span> only in the high permeability zone at low injection rates with the mechanism shifting from capillary fingering to viscous fingering with increasing flow rate. At high injection rates, LCO2 displaced <span class="hlt">water</span> in the low permeability zone with capillary fingering as the dominant mechanism. LCO2 saturation (SLCO2) as a function of injection rate was quantified using fluorescent microscopy. In all experiments, more than 50% of LCO2 resided in the active flowpaths, and this fraction increased as displacement transitioned from capillary to viscous fingering. A continuum-scale two-phase flow model with independently determined fluid and hydraulic parameters was used to predict SLCO2 in the dual-permeability field. Agreement with the micromodel experiments was obtained for low injection rates. However, the numerical model does not account for the unstable viscous fingering processes observed experimentally at higher rates and hence overestimated SLCO2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/20075700','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/20075700"><span>Behavior of trace metals in the sediment <span class="hlt">pore</span> <span class="hlt">waters</span> of intertidal mudflats of a tropical wetland</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yu, K.T.; Lam, M.H.W.; Yen, Y.F.; Leung, A.P.K.</p> <p>2000-03-01</p> <p>Vertical profiles of dissolved Cd, Cr, Cu, Pb, Zn, Fe, and Mn in the sediment <span class="hlt">pore</span> <span class="hlt">waters</span> of the intertidal mudflats of the Mai Po and Inner Deep Bay Ramsar Site of Hong Kong, People's Republic of China, were measured using the polyacrylamide gel diffusive equilibration thin film (DET) technique. The ranges of concentrations of dissolved Cd, Cr, Cu, Pb, Zn, Fe, and Mn in the <span class="hlt">pore</span> <span class="hlt">water</span> of the top 0 to 20 cm of sediment were 2.2 to 10.0 nM, 346.0 to 950.0 nM 243.8 to 454.8 nM, 23.2 to 51.2 nM, 39.8 to 249.5 {micro}M, and 13.4 to 20.7 {micro}M, respectively. Enrichment of these trace metals was observed in the upper 0- to 7-cm layer. Profiles of conditional distribution coefficient, log(K{sub D}), of the trace metals and results of multiple regression analysis have revealed that reduction of Mn (hydrous) oxides was the major remobilization mechanism for Cd, Cr, Cu, Pb, and Zn in the mudflats. Benthic diffusive fluxes of these trace metals from the mudflats were also estimated on the basis of the concentration gradients of trace metals between surface sediments and the overlying <span class="hlt">water</span> column. The magnitude of the estimated diffusive fluxes followed the order Zn > Cr > Cu > Pb > Cd.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4898891','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4898891"><span>Evaluation of Bound and <span class="hlt">Pore</span> <span class="hlt">Water</span> in Cortical Bone Using Ultrashort Echo Time (UTE) Magnetic Resonance Imaging</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Shao, Hongda; D'Lima, Darryl; Bydder, Graeme M; Wu, Zhihong; Du, Jiang</p> <p>2015-01-01</p> <p>Bone <span class="hlt">water</span> exists in different states with the majority bound to the organic matrix and to mineral, and a smaller fraction in ‘free’ form in the <span class="hlt">pores</span> of cortical bone. In this study we aimed to develop and evaluate ultrashort echo time (UTE) magnetic resonance imaging (MRI) techniques for assessment of T2*, T1 and concentration of collagen-bound and <span class="hlt">pore</span> <span class="hlt">water</span> in cortical bone using a 3T clinical whole-body scanner. UTE MRI together with an isotope study using tritiated and distilled <span class="hlt">water</span> (THO-H2O) exchange as well as gravimetrical analysis were performed on ten sectioned bovine bone samples. In addition, 32 human cortical bone samples were prepared for comparison between <span class="hlt">pore</span> <span class="hlt">water</span> concentration measured with UTE MRI and cortical porosity derived from micro computed tomography (μCT). A short T2* of 0.27 ± 0.03 ms and T1 of 116±6 ms were observed for collagen-bound <span class="hlt">water</span> in bovine bone. A longer T2* of 1.84 ± 0.52 ms and T1 of 527±28 ms were observed for <span class="hlt">pore</span> <span class="hlt">water</span> in bovine bone. UTE MRI measurements showed a <span class="hlt">pore</span> <span class="hlt">water</span> concentration of 4.7-5.3% by volume and collagen-bound <span class="hlt">water</span> concentration of 15.7-17.9% in bovine bone. THO-H2O exchange studies showed a <span class="hlt">pore</span> <span class="hlt">water</span> concentration of 5.9 ± 0.6% and collagen-bound <span class="hlt">water</span> concentration of 18.1 ± 2.1% in bovine bone. Gravimetrical analysis showed a <span class="hlt">pore</span> <span class="hlt">water</span> concentration of 6.3 ± 0.8% and collagen-bound <span class="hlt">water</span> concentration of 19.2 ± 3.6% in bovine bone. A mineral <span class="hlt">water</span> concentration of 9.5 ± 0.6% was derived in bovine bone with the THO-H2O exchange study. UTE measured <span class="hlt">pore</span> <span class="hlt">water</span> concentration is highly correlated (R2 = 0.72, P < 0.0001) with μCT porosity in the human cortical bone study. Both bovine and human bone studies suggest that UTE sequences could reliably measure collagen-bound and <span class="hlt">pore</span> <span class="hlt">water</span> concentration in cortical bone using a clinical scanner. PMID:26527298</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/90942','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/90942"><span>Meteoric-like fabrics forming in <span class="hlt">marine</span> <span class="hlt">waters</span>. Implications for the use of petrography to identify diagenetic environments</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Melim, L.A.; Swart, P.K.; Maliva, R.G.</p> <p>1995-08-01</p> <p>Petrographic fabrics have long been used to identify meteoric diagnesis of carbonate sediments. However, on the basis of oxygen isotopic data, we document similar fabrics forming in <span class="hlt">marine</span> <span class="hlt">pore</span> fluids in the shallow subsurface of Great Bahama Bank. Therefore, petrographic fabrics alone are not reliable indicators of diagenetic environments, even for shallow-<span class="hlt">water</span> sediments. In our study, skeletal grainstones show two distinct diagenetic assemblages: either dissolution of aragonitic grains and minimal cementation (high-permeability intervals) or abundant blocky spar cement and neomorphism of aragonitic skeletal grains (low-permeability intervals). These <span class="hlt">marine</span>-burial fabrics are present as shallow as 110 m below sea level, well above the aragonite compensation depth, a feature that must be considered for models of diagenesis in ancient carbonate sediments. <span class="hlt">Marine</span>-burial diagenesis may be important in ancient carbonate sediments deposited in moderate <span class="hlt">water</span> depths or in shallow <span class="hlt">water</span> during rising sea level where meteoric diagenesis is suppressed. 17 refs., 5 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19780062895&hterms=Water+buffalo&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DWater%2Bbuffalo','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19780062895&hterms=Water+buffalo&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DWater%2Bbuffalo"><span><span class="hlt">Water</span> vapor weathering of Taurus-Littrow orange soil - A <span class="hlt">pore</span>-structure analysis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cadenhead, D. A.; Mikhail, R. S.</p> <p>1975-01-01</p> <p>A <span class="hlt">pore</span>-volume analysis was performed on <span class="hlt">water</span> vapor adsorption data previously obtained on a fresh sample of Taurus-Littrow orange soil, and the analysis was repeated on the same sample after its exposure to moist air for a period of approximately six months. The results indicate that exposure of an outgassed sample to high relative pressures of <span class="hlt">water</span> vapor can result in the formation of substantial micropore structure, the precise amount being dependent on the sample pretreatment, particularly the outgassing temperature. Micropore formation is explained in terms of <span class="hlt">water</span> penetration into surface defects. In contrast, long-term exposure to moist air at low relative pressures appears to reverse the process with the elimination of micropores and enlargement of mesopores possibly through surface diffusion of metastable adsorbent material. The results are considered with reference to the storage of lunar samples.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25427672','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25427672"><span><span class="hlt">Water</span> transport in the nano-<span class="hlt">pore</span> of the calcium silicate phase: reactivity, structure and dynamics.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hou, Dongshuai; Li, Zongjin; Zhao, Tiejun; Zhang, Peng</p> <p>2015-01-14</p> <p>Reactive force field molecular dynamics was utilized to simulate the reactivity, structure and dynamics of <span class="hlt">water</span> molecules confined in calcium-silicate-hydrate (C-S-H) nano-<span class="hlt">pores</span> of 4.5 nm width. Due to the highly reactive C-S-H surface, hydrolytic reactions occur in the solid-liquid interfacial zone, and partially surface adsorbed <span class="hlt">water</span> molecules transforming into the Si-OH and Ca-OH groups are strongly embedded in the C-S-H structure. Due to the electronic charge difference, the silicate and calcium hydroxyl groups have binomial distributions of the dipolar moment and <span class="hlt">water</span> orientation. While Ca-OH contributes to the Ow-downward orientation, the ONB atoms in the silicate chains prefer to accept H-bonds from the surface <span class="hlt">water</span> molecules. Furthermore, the defective silicate chains and solvated Caw atoms near the surface contribute to the glassy nature of the surface <span class="hlt">water</span> molecules, with large packing density, pronounced orientation preference, and distorted organization. The stable H-bonds connected with the Ca-OH and Si-OH groups also restrict the mobility of the surface <span class="hlt">water</span> molecules. The significant reduction of the diffusion coefficient matches well with the experimental results obtained by NMR, QENS and PCFR techniques. Upon increasing the distance from the channel, the structural and dynamic behavior of the <span class="hlt">water</span> molecules varies and gradually translates into bulk <span class="hlt">water</span> properties at distances of 10-15 Å from the liquid-solid interface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011NatGe...4..298L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011NatGe...4..298L"><span>Methylation of inorganic mercury in polar <span class="hlt">marine</span> <span class="hlt">waters</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lehnherr, Igor; St. Louis, Vincent L.; Hintelmann, Holger; Kirk, Jane L.</p> <p>2011-05-01</p> <p>Monomethylmercury is a neurotoxin that accumulates in <span class="hlt">marine</span> organisms, with serious implications for human health. The toxin is of particular concern to northern Inuit peoples, for example, whose traditional diets are composed primarily of <span class="hlt">marine</span> mammals and fish. The ultimate source of monomethylmercury to <span class="hlt">marine</span> organisms has remained uncertain, although various potential sources have been proposed, including export from coastal and deep-sea sediments and major river systems, atmospheric deposition and <span class="hlt">water</span>-column production. Here, we report results from incubation experiments in which we added isotopically labelled inorganic mercury and monomethylmercury to seawater samples collected from a range of sites in the Canadian Arctic Archipelago. Monomethylmercury formed from the methylation of inorganic mercury in all samples. Demethylation of monomethylmercury was also observed in <span class="hlt">water</span> from all sites. We determined steady-state concentrations of monomethylmercury in <span class="hlt">marine</span> <span class="hlt">waters</span> by incorporating the rate constants for monomethylmercury formation and degradation derived from these experiments into a numerical model. We estimate that the conversion of inorganic mercury to monomethylmercury in the <span class="hlt">water</span> column accounts for around 47% (+/-62%, standard deviation) of the monomethylmercury present in polar <span class="hlt">marine</span> <span class="hlt">waters</span>, with site-to-site differences in inorganic mercury and monomethylmercury levels accounting for most of the variability. We suggest that <span class="hlt">water</span>-column methylation of inorganic mercury is a significant source of monomethylmercury in pelagic <span class="hlt">marine</span> food webs in the Arctic, and possibly in the world's oceans in general.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26266899','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26266899"><span>Occurrence and significance of polychlorinated biphenyls in <span class="hlt">water</span>, sediment <span class="hlt">pore</span> <span class="hlt">water</span> and surface sediments of Umgeni River, KwaZulu-Natal, South Africa.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gakuba, Emmanuel; Moodley, Brenda; Ndungu, Patrick; Birungi, Grace</p> <p>2015-09-01</p> <p>The Umgeni River is one of the main sources of <span class="hlt">water</span> in KwaZulu-Natal, South Africa; however; there is currently a lack of information on the presence and distribution of polychlorinated biphenyls (PCBs) in its sediment, sediment <span class="hlt">pore</span> <span class="hlt">water</span> and surface <span class="hlt">water</span>. This study aims to determine the occurrence and significance of selected PCBs in the surface <span class="hlt">water</span>, sediment <span class="hlt">pore</span> <span class="hlt">water</span> and surface sediment samples from the Umgeni River. Liquid-liquid and soxhlet extractions were used for <span class="hlt">water</span> or <span class="hlt">pore</span> <span class="hlt">water</span>, and sediments, respectively. Extracts were cleaned up using a florisil column and analysed by gas chromatography-mass spectrometry. The total concentrations of eight polychlorinated biphenyls were 6.91-21.69 ng/mL, 40.67-252.30 ng/mL and 102.60-427.80 ng/g (dry weight), in unfiltered surface <span class="hlt">water</span>, unfiltered sediment <span class="hlt">pore</span> <span class="hlt">water</span> and surface sediments, respectively. The percentage contributions of various matrices were 4, 36 and 60 % for unfiltered surface <span class="hlt">water</span>, unfiltered <span class="hlt">pore</span> <span class="hlt">water</span> and sediment, respectively. The highest concentrations of PCBs were found in <span class="hlt">water</span>, <span class="hlt">pore</span> <span class="hlt">water</span> and sediment collected from sampling sites close to the Northern Wastewater Treatment Works. The highest chlorinated biphenyl, PCB 180, was the most abundant at almost all sampling sites. To our knowledge, this is the first report on occurrence of polychlorinated biphenyls in the Umgeni River <span class="hlt">water</span>, <span class="hlt">pore</span> <span class="hlt">water</span> and sediment system and our results provide valuable information regarding the partitioning of the PCBs between the <span class="hlt">water</span> and sediment systems as well as the organic chemical quality of the <span class="hlt">water</span>.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/355592','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/355592"><span>Toxicity identification evaluation of metal-contaminated sediments using an artificial <span class="hlt">pore</span> <span class="hlt">water</span> containing dissolved organic carbons</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Boucher, A.M.; Watzin, M.C.</p> <p>1999-03-01</p> <p>Recent investigations of sediment-associated pollutants in Lake Champlain indicated significant contamination with As, Mn, and Ni in Outer Malletts Bay, Vermont, US. Ceriodaphnia dubia exposed to sediment <span class="hlt">pore</span> <span class="hlt">water</span> from several sites in Outer Malletts Bay showed repeatable, acute mortality at only one site. A toxicity identification evaluation (TIE) was conducted on <span class="hlt">pore</span> <span class="hlt">water</span> to determine the contaminants causing mortality at this site. Unlike most TIE applications, the dilution <span class="hlt">water</span> used in these tests was formulated to match the hardness, alkalinity, pH, conductivity, and dissolved organic carbon content of the <span class="hlt">pore</span> <span class="hlt">water</span>. Results from phase 1 of the TIE indicated that divalent metals may be responsible for toxicity. Phase 2 results revealed levels of Mn above LC50 values. Spiking experiments employed in phase 3 confirmed Mn as the principal toxicant in sediment <span class="hlt">pore</span> <span class="hlt">water</span>. The formulated <span class="hlt">pore</span> <span class="hlt">water</span> worked well and helped ensure that toxicant behavior was influenced primarily by each TIE manipulation and not by physical and chemical differences between the dilution and site <span class="hlt">water</span>. Although the Mn toxicity at this site may be the result of its unique geomorphology, this situation underscores the need to look broadly for potential toxicants when evaluating contaminated sites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.H53B1036V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.H53B1036V"><span>Solute contributions from precipitation to the compositions of soil <span class="hlt">waters</span> in a <span class="hlt">marine</span> terrace chronosequence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vivit, D. V.; White, A. F.; Bullen, T. D.; Fitzpatrick, J.</p> <p>2010-12-01</p> <p>Solute loading of soil <span class="hlt">waters</span> by rainfall together with evapo-transpiration can increase the concentrations of various dissolved constituents. This process complicates the modeling of saturation states for the different mineral phases in the soil profile that are products of the weathering of primary minerals found in the original granitic source material. The estimation of true rates of regolith weathering due to CO2 drawdown at temperate hydrogeological sites requires having soil <span class="hlt">pore</span> <span class="hlt">water</span> solute concentration data which have been corrected for solute inputs from precipitation before proceeding with chemical weathering calculations. As part of a chemical weathering study of a coastal <span class="hlt">marine</span> terrace chronosequence located in the vicinity of Wilder Ranch State Park, Santa Cruz County, CA, bulk samplers and automatic precipitation-event samplers installed at a range of sites enabled us to determine elemental concentrations and isotopic compositions of rainfall solutes which influence the overall compositions of the <span class="hlt">pore</span> <span class="hlt">waters</span>. Variations in rain sample chemistry (mole-ratio data using Na, Mg, Ca, Cl and SO4) correlated with precipitation intensity result from solute inputs contributed by <span class="hlt">marine</span> and terrestrial aerosols. Higher strontium-isotope ratios (87Sr/86Sr), which point to radiogenic dust sources, occur in rain <span class="hlt">water</span> collected in the fall at the beginning of the rainy season while lower ratio values indicating <span class="hlt">marine</span> aerosol sources appear in winter and spring samples. Use of the NOAA HYSPLIT particle-tracking program for computing the chronological progression of storm tracks during precipitation events could show the development of solute levels in rain. Subsequently, the installation of wind sensors along with the automatic rain collectors afforded the capability of correlating high resolution wind-speed and wind-direction data with changing compositions of rain samples collected at fixed-time intervals during storm events. Wind data show that wind</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/477292','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/477292"><span>Geochemical properties of bentonite <span class="hlt">pore</span> <span class="hlt">water</span> in high-level-waste repository condition</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ohe, Toshiaki; Tsukamoto, Masaki</p> <p>1997-04-01</p> <p>The chemically favorable nature of bentonite <span class="hlt">pore</span> <span class="hlt">water</span> is clarified by the PHREEQE geochemical simulation code. Bentonite is viewed as a candidate buffer material for a high-level-waste repository, and bentonite`s <span class="hlt">pore</span> <span class="hlt">water</span> chemistry is expected to result in a reduced Eh and weak alkaline pH region. Pyrite (Fe{sub 2}S), initially contained in bentonite, alters to magnetite (Fe{sub 3}O{sub 4}), and this redox couple reaction controls the oxidation reduction potential. A mild alkaline pH condition is produced mainly by an ion exchange reaction between the sodium in bentonite and the protons in the solution. A geochemical simulation of the ion exchange reactions and the pyrite-magnetite alteration suggests that a favorable chemical condition would exist during the waste glass dissolution and indicates that the Ph and the Eh values are {minus}7.5 to {minus}9.4 and {minus}450 to {minus}320 mV, respectively, when the granitic groundwater intrudes into the compacted bentonite in the repository.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22764500','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22764500"><span>Trophic cascade induced by molluscivore predator alters <span class="hlt">pore-water</span> biogeochemistry via competitive release of prey.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>van Gils, Jan A; van der Geest, Matthijs; Jansen, Erik J; Govers, Laura L; de Fouw, Jimmy; Piersma, Theunis</p> <p>2012-05-01</p> <p>Effects of predation may cascade down the food web. By alleviating interspecific competition among prey, predators may promote biodiversity, but the precise mechanisms of how predators alter competition have remained elusive. Here we report on a predator-exclosure experiment carried out in a tropical intertidal ecosystem, providing evidence for a three-level trophic cascade induced by predation by molluscivore Red Knots (Calidris canutus) that affects <span class="hlt">pore</span> <span class="hlt">water</span> biogeochemistry. In the exclosures the knots' favorite prey (Dosinia isocardia) became dominant and reduced the individual growth rate in an alternative prey (Loripes lucinalis). Dosinia, a suspension feeder, consumes suspended particulate organic matter (POM), whereas Loripes is a facultative mixotroph, partly living on metabolites produced by sulfur-oxidizing chemoautotrophic bacteria, but also consuming suspended POM. Reduced sulfide concentrations in the exclosures suggest that, without predation on Dosinia, stronger competition for suspended POM forces Loripes to rely on energy produced by endosymbiotic bacteria, thus leading to an enhanced uptake of sulfide from the surrounding <span class="hlt">pore</span> <span class="hlt">water</span>. As sulfide is toxic to most organisms, this competition-induced diet shift by Loripes may detoxify the environment, which in turn may facilitate other species. The inference that predators affect the toxicity of their environment via a multi-level trophic cascade is novel, but we believe it may be a general phenomenon in detritus-based ecosystems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25569179','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25569179"><span>Chabazite: stable cation-exchanger in hyper alkaline concrete <span class="hlt">pore</span> <span class="hlt">water</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Van Tendeloo, Leen; Wangermez, Wauter; Kurttepeli, Mert; de Blochouse, Benny; Bals, Sara; Van Tendeloo, Gustaaf; Martens, Johan A; Maes, André; Kirschhock, Christine E A; Breynaert, Eric</p> <p>2015-02-17</p> <p>To avoid impact on the environment, facilities for permanent disposal of hazardous waste adopt multibarrier design schemes. As the primary barrier very often consists of cement-based materials, two distinct aspects are essential for the selection of suitable complementary barriers: (1) selective sorption of the contaminants in the repository and (2) long-term chemical stability in hyperalkaline concrete-derived media. A multidisciplinary approach combining experimental strategies from environmental chemistry and materials science is therefore essential to provide a reliable assessment of potential candidate materials. Chabazite is typically synthesized in 1 M KOH solutions but also crystallizes in simulated young cement <span class="hlt">pore</span> <span class="hlt">water</span>, a pH 13 aqueous solution mainly containing K(+) and Na(+) cations. Its formation and stability in this medium was evaluated as a function of temperature (60 and 85 °C) over a timeframe of more than 2 years and was also asessed from a mechanistic point of view. Chabazite demonstrates excellent cation-exchange properties in simulated young cement <span class="hlt">pore</span> <span class="hlt">water</span>. Comparison of its Cs(+) cation exchange properties at pH 8 and pH 13 unexpectedly demonstrated an increase of the KD with increasing pH. The combined results identify chabazite as a valid candidate for inclusion in engineered barriers for concrete-based waste disposal.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..1210970R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..1210970R"><span><span class="hlt">Pore</span> <span class="hlt">water</span> pressure variations in Subpermafrost groundwater : Numerical modeling compared with experimental modeling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rivière, Agnès.; Goncalves, Julio; Jost, Anne; Font, Marianne</p> <p>2010-05-01</p> <p>Development and degradation of permafrost directly affect numerous hydrogeological processes such as thermal regime, exchange between river and groundwater, groundwater flows patterns and groundwater recharge (Michel, 1994). Groundwater in permafrost area is subdivided into two zones: suprapermafrost and subpermafrost which are separated by permafrost. As a result of the volumetric expansion of <span class="hlt">water</span> upon freezing and assuming ice lenses and frost heave do not form freezing in a saturated aquifer, the progressive formation of permafrost leads to the pressurization of the subpermafrost groundwater (Wang, 2006). Therefore disappearance or aggradation of permafrost modifies the confined or unconfined state of subpermafrost groundwater. Our study focuses on modifications of <span class="hlt">pore</span> <span class="hlt">water</span> pressure of subpermafrost groundwater which could appear during thawing and freezing of soil. Numerical simulation allows elucidation of some of these processes. Our numerical model accounts for phase changes for coupled heat transport and variably saturated flow involving cycles of freezing and thawing. The flow model is a combination of a one-dimensional channel flow model which uses Manning-Strickler equation and a two-dimensional vertically groundwater flow model using Richards equation. Numerical simulation of heat transport consisted in a two dimensional model accounting for the effects of latent heat of phase change of <span class="hlt">water</span> associated with melting/freezing cycles which incorporated the advection-diffusion equation describing heat-transfer in porous media. The change of hydraulic conductivity and thermal conductivity are considered by our numerical model. The model was evaluated by comparing predictions with data from laboratory freezing experiments. Experimental design was undertaken at the Laboratory M2C (Univesité de Caen-Basse Normandie, CNRS, France). The device consisted of a Plexiglas box insulated on all sides except on the top. Precipitation and ambient temperature are</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70020892','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70020892"><span>Changes in14c activity over time during vacuum distillation of carbon from rock <span class="hlt">pore</span> <span class="hlt">water</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Davidson, G.R.; Yang, I.C.</p> <p>1999-01-01</p> <p>The radiocarbon activity of carbon collected by vacuum distillation from a single partially saturated tuff began to decline after approximately 60% of the <span class="hlt">water</span> and carbon had been extracted. Disproportionate changes in 14C activity and ??13C during distillation rule out simple isotopic fractionation as a causative explanation. Additional phenomena such as matrix diffusion and ion exclusion in micropores may play a role in altering the isotopic value of extracted carbon, but neither can fully account for the observed changes. The most plausible explanation is that distillation recovers carbon from an adsorbed phase that is depleted in 14C relative to DIC in the bulk <span class="hlt">pore</span> <span class="hlt">water</span>. ?? 1999 by the Arizona Board of Regents on behalf of the University of Arizona.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4507585','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4507585"><span>Investigation of Two Novel Approaches for Detection of Sulfate Ion and Methane Dissolved in Sediment <span class="hlt">Pore</span> <span class="hlt">Water</span> Using Raman Spectroscopy</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Du, Zengfeng; Chen, Jing; Ye, Wangquan; Guo, Jinjia; Zhang, Xin; Zheng, Ronger</p> <p>2015-01-01</p> <p>The levels of dissolved sulfate and methane are crucial indicators in the geochemical analysis of <span class="hlt">pore</span> <span class="hlt">water</span>. Compositional analysis of <span class="hlt">pore</span> <span class="hlt">water</span> samples obtained from sea trials was conducted using Raman spectroscopy. It was found that the concentration of SO42− in <span class="hlt">pore</span> <span class="hlt">water</span> samples decreases as the depth increases, while the expected Raman signal of methane has not been observed. A possible reason for this is that the methane escaped after sampling and the remaining concentration of methane is too low to be detected. To find more effective ways to analyze the composition of <span class="hlt">pore</span> <span class="hlt">water</span>, two novel approaches are proposed. One is based on Liquid Core Optical Fiber (LCOF) for detection of SO42−. The other one is an enrichment process for the detection of CH4. With the aid of LCOF, the Raman signal of SO42− is found to be enhanced over 10 times compared to that obtained by a conventional Raman setup. The enrichment process is also found to be effective in the investigation to the prepared sample of methane dissolved in <span class="hlt">water</span>. By CCl4 extraction, methane at a concentration below 1.14 mmol/L has been detected by conventional Raman spectroscopy. All the obtained results suggest that the approach proposed in this paper has great potential to be developed as a sensor for SO42− and CH4 detection in <span class="hlt">pore</span> <span class="hlt">water</span>. PMID:26016919</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4824874','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4824874"><span>Praziquantel degradation in <span class="hlt">marine</span> aquarium <span class="hlt">water</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Dawson, Matthew R.; Ellis, Helen; Stamper, M. Andrew</p> <p>2016-01-01</p> <p>Praziquantel (PZQ) is a drug commonly utilized to treat both human schistosomiasis and some parasitic infections and infestations in animals. In the aquarium industry, PZQ can be administered in a “bath” to treat the presence of ectoparasites on both the gills and skin of fish and elasmobranchs. In order to fully treat an infestation, the bath treatment has to maintain therapeutic levels of PZQ over a period of days or weeks. It has long been assumed that, once administered, PZQ is stable in a <span class="hlt">marine</span> environment throughout the treatment interval and must be mechanically removed, but no controlled experiments have been conducted to validate that claim. This study aimed to determine if PZQ would break down naturally within a <span class="hlt">marine</span> aquarium below its 2 ppm therapeutic level during a typical 30-day treatment: and if so, does the presence of fish or the elimination of all living biological material impact the degradation of PZQ? Three 650 L <span class="hlt">marine</span> aquarium systems, each containing 12 fish (French grunts: Haemulon flavolineatum), and three 650 L <span class="hlt">marine</span> aquariums each containing no fish were treated with PZQ (2 ppm) and concentrations were measured daily for 30 days. After one round of treatment, the PZQ was no longer detectable in any system after 8 (±1) days. The subsequent two PZQ treatments yielded even faster PZQ breakdown (non-detectable after 2 days and 2 ± 1 day, respectively) with slight variations between systems. Linear mixed effects models of the data indicate that day and trial most impact PZQ degradation, while the presence of fish was not a factor in the best-fit models. In a completely sterilized <span class="hlt">marine</span> system (0.5 L) PZQ concentration remained unchanged over 15 days, suggesting that PZQ may be stable in a <span class="hlt">marine</span> system during this time period. The degradation observed in non-sterile <span class="hlt">marine</span> systems in this study may be microbial in nature. This work should be taken into consideration when providing PZQ bath treatments to <span class="hlt">marine</span> animals to ensure</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27069797','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27069797"><span>Praziquantel degradation in <span class="hlt">marine</span> aquarium <span class="hlt">water</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Thomas, Amber; Dawson, Matthew R; Ellis, Helen; Stamper, M Andrew</p> <p>2016-01-01</p> <p>Praziquantel (PZQ) is a drug commonly utilized to treat both human schistosomiasis and some parasitic infections and infestations in animals. In the aquarium industry, PZQ can be administered in a "bath" to treat the presence of ectoparasites on both the gills and skin of fish and elasmobranchs. In order to fully treat an infestation, the bath treatment has to maintain therapeutic levels of PZQ over a period of days or weeks. It has long been assumed that, once administered, PZQ is stable in a <span class="hlt">marine</span> environment throughout the treatment interval and must be mechanically removed, but no controlled experiments have been conducted to validate that claim. This study aimed to determine if PZQ would break down naturally within a <span class="hlt">marine</span> aquarium below its 2 ppm therapeutic level during a typical 30-day treatment: and if so, does the presence of fish or the elimination of all living biological material impact the degradation of PZQ? Three 650 L <span class="hlt">marine</span> aquarium systems, each containing 12 fish (French grunts: Haemulon flavolineatum), and three 650 L <span class="hlt">marine</span> aquariums each containing no fish were treated with PZQ (2 ppm) and concentrations were measured daily for 30 days. After one round of treatment, the PZQ was no longer detectable in any system after 8 (±1) days. The subsequent two PZQ treatments yielded even faster PZQ breakdown (non-detectable after 2 days and 2 ± 1 day, respectively) with slight variations between systems. Linear mixed effects models of the data indicate that day and trial most impact PZQ degradation, while the presence of fish was not a factor in the best-fit models. In a completely sterilized <span class="hlt">marine</span> system (0.5 L) PZQ concentration remained unchanged over 15 days, suggesting that PZQ may be stable in a <span class="hlt">marine</span> system during this time period. The degradation observed in non-sterile <span class="hlt">marine</span> systems in this study may be microbial in nature. This work should be taken into consideration when providing PZQ bath treatments to <span class="hlt">marine</span> animals to ensure maximum</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.C53A0551R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.C53A0551R"><span>A combined experimental and numerical study of <span class="hlt">pore</span> <span class="hlt">water</span> pressure variations in sub-permafrost groundwater</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rivière, A.; Anne, J.; Goncalves, J.</p> <p>2013-12-01</p> <p>The past few decades have seen a rapid development and progress in research on past and current hydrologic impacts of permafrost evolution. In permafrost area, groundwater is subdivided into two zones: supra-permafrost and sub-permafrost which are separated by permafrost. Knowledge of the sub-permafrost aquifers is often lacking due to the difficulty to access those systems. The few available data show that this aquifers are generally artesian below the continuous permafrost. In the literature, there are two plausible explanations for the relatively high <span class="hlt">pore</span> pressures in the sub-permafrost aquifer; the recharge related to the ice sheet melting and the expulsion of <span class="hlt">water</span> related to the ice expansion. In this study, we investigated areas where ice sheets have never developed like in the Paris basin region. The ice expansion induces also soil surface uplift. Our study focuses on modifications of <span class="hlt">pore</span> <span class="hlt">water</span> pressure in the sub-permafrost aquifer and the soil surface motion during the permafrost development (freezing front deepening). To fill in the gaps to the field data availability, we developed an experimental approach. Experimental design was undertaken at the Laboratory M2C (Université de Caen-Basse Normandie, CNRS, France). The device consisted in a 2 m2 box insulated at all sides except on the top where a surface temperature was prescribed. The box is filled with silty sand of which hydraulics and thermal parameters are known. Soil temperatures, <span class="hlt">pore</span> <span class="hlt">water</span> pressure and soil motion are continuously recorded at different elevations in the sand-box. We developed a two-dimensional transient fully coupled heat and <span class="hlt">water</span> transport model to simulate thawing and freezing processes taking into account the phase change (Latent heat effects). The balance equations are solved using of a finite difference numerical scheme. Experimental results are used to verify the implementation of the hydro-mechanical processes in our numerical simulations. Experimental and numerical</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/1993/4144/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/1993/4144/report.pdf"><span><span class="hlt">Pore-water</span> extraction from unsaturated tuff by triaxial and one-dimensional compression methods, Nevada Test Site, Nevada</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Mower, Timothy E.; Higgins, Jerry D.; Yang, In C.; Peters, Charles A.</p> <p>1994-01-01</p> <p>Study of the hydrologic system at Yucca Mountain, Nevada, requires the extraction of <span class="hlt">pore-water</span> samples from welded and nonwelded, unsaturated tuffs. Two compression methods (triaxial compression and one-dimensional compression) were examined to develop a repeatable extraction technique and to investigate the effects of the extraction method on the original <span class="hlt">pore</span>-fluid composition. A commercially available triaxial cell was modified to collect <span class="hlt">pore</span> <span class="hlt">water</span> expelled from tuff cores. The triaxial cell applied a maximum axial stress of 193 MPa and a maximum confining stress of 68 MPa. Results obtained from triaxial compression testing indicated that <span class="hlt">pore-water</span> samples could be obtained from nonwelded tuff cores that had initial moisture contents as small as 13 percent (by weight of dry soil). Injection of nitrogen gas while the test core was held at the maximum axial stress caused expulsion of additional <span class="hlt">pore</span> <span class="hlt">water</span> and reduced the required initial moisture content from 13 to 11 percent. Experimental calculations, together with experience gained from testing moderately welded tuff cores, indicated that the triaxial cell used in this study could not apply adequate axial or confining stress to expel <span class="hlt">pore</span> <span class="hlt">water</span> from cores of densely welded tuffs. This concern led to the design, fabrication, and testing of a one-dimensional compression cell. The one-dimensional compression cell used in this study was constructed from hardened 4340-alloy and nickel-alloy steels and could apply a maximum axial stress of 552 MPa. The major components of the device include a corpus ring and sample sleeve to confine the sample, a piston and base platen to apply axial load, and drainage plates to transmit expelled <span class="hlt">water</span> from the test core out of the cell. One-dimensional compression extracted <span class="hlt">pore</span> <span class="hlt">water</span> from nonwelded tuff cores that had initial moisture contents as small as 7.6 percent; <span class="hlt">pore</span> <span class="hlt">water</span> was expelled from densely welded tuff cores that had initial moisture contents as small as 7</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EP%26S...66..137T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EP%26S...66..137T"><span>Origin and transport of <span class="hlt">pore</span> fluids in the Nankai accretionary prism inferred from chemical and isotopic compositions of <span class="hlt">pore</span> <span class="hlt">water</span> at cold seep sites off Kumano</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Toki, Tomohiro; Higa, Ryosaku; Ijiri, Akira; Tsunogai, Urumu; Ashi, Juichiro</p> <p>2014-12-01</p> <p>We used push corers during manned submersible dives to obtain sediment samples of up to 30 cm from the subseafloor at the Oomine Ridge. The concentrations of B in <span class="hlt">pore</span> <span class="hlt">water</span> extracted from the sediment samples from cold seep sites were higher than could be explained by organic matter decomposition, suggesting that the seepage fluid at the site was influenced by B derived from smectite-illite alteration, which occurs between 50°C and 160°C. Although the negative δ18OH2O and δDH2O values of the <span class="hlt">pore</span> fluids cannot be explained by freshwater derived from clay mineral dehydration (CMD), we considered the contribution of <span class="hlt">pore</span> fluids in the shallow sediments of the accretionary prism, which showed negative δ18OH2O and δDH2O values according to the results obtained during Integrated Ocean Drilling Program (IODP) Expeditions 315 and 316. We calculated the mixing ratios based on a four-end-member mixing model including freshwater derived from CMD, <span class="hlt">pore</span> fluids in the shallow (SPF) accretionary prism sediment, seawater (SW), and freshwater derived from methane hydrate (MH) dissociation. However, the Oomine seep fluids were unable to be explained without four end members, suggesting that deep-sourced fluids in the accretionary prism influenced the seeping fluids from this area. This finding presents the first evidence of deep-sourced fluids at cold seep sites in the Oomine Ridge, indicating that a megasplay fault is a potential pathway for the deep-sourced fluids.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.B34A..04L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.B34A..04L"><span>Determining Carbonate Concretion Formation Temperatures and <span class="hlt">Pore</span> <span class="hlt">Water</span> δ18O Values Using the Clumped Isotope Approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Loyd, S. J.; Corsetti, F. A.; Tripati, A. K.</p> <p>2010-12-01</p> <p>The porosity/permeability of siliciclastic strata is affected by post-depositional cementation, but determining at what depth and under what conditions cementation occurs is difficult with standard techniques. The oxygen isotopic composition of solid phase carbonate cements (δ18Ocarb) can be related to temperature (and by extension depth) of formation, and thus has been widely used in diagenetic studies. However, δ18Ocarb paleothermometry requires the prediction or assumption of <span class="hlt">pore</span> <span class="hlt">water</span> δ18O (δ18Opw), a parameter that is poorly constrained in past diagenetic environments (for convenience δ18Opw is usually assumed to be 0‰ VSMOW). Here, we use clumped isotope thermometry (CIT)—a fluid δ18O-independent temperature proxy—to avoid the often ambiguous yet necessary δ18Opw assumption applied to δ18Ocarb paleothermometery and reevaluate the temperature of carbonate concretion formation in the Miocene Monterey Formation (dolomite) and the Cretaceous Holz Shale (calcite) of southern California. CIT analysis of Monterey Formation concretions produced slightly increased temperatures of formation versus traditional δ18Ocarb paleothermometry, whereas the Holz Shale concretions produced significantly decreased temperatures. Inputting the CIT-derived temperature into the associated δ18Ocarb-temperature equation allows the calculation of the ancient δ18Opw. Calculated δ18Opw values range from ~ -8 to +2‰ VSMOW, significantly different from coeval seawater. δ18Opw less than 0‰ can be generated by a number of processes including the influx of non-<span class="hlt">marine</span> fluids and/or hydrate formation, whereas δ18Opw greater than 0‰ can be produced by silicate diagenesis, influx of evaporative brines, or hydrate dissolution. These data demonstrate that <span class="hlt">pore</span> <span class="hlt">water</span> modifying diagenetic processes were operating in past environments and emphasize that the formation temperatures of diagenetic carbonates should be calculated using a fluid δ18O-independent approach, such as</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatSR...621886S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatSR...621886S"><span>Active Sampling Device for Determining Pollutants in Surface and <span class="hlt">Pore</span> <span class="hlt">Water</span> – the In Situ Sampler for Biphasic <span class="hlt">Water</span> Monitoring</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Supowit, Samuel D.; Roll, Isaac B.; Dang, Viet D.; Kroll, Kevin J.; Denslow, Nancy D.; Halden, Rolf U.</p> <p>2016-02-01</p> <p>We designed and evaluated an active sampling device, using as analytical targets a family of pesticides purported to contribute to honeybee colony collapse disorder. Simultaneous sampling of bulk <span class="hlt">water</span> and <span class="hlt">pore</span> <span class="hlt">water</span> was accomplished using a low-flow, multi-channel pump to deliver <span class="hlt">water</span> to an array of solid-phase extraction cartridges. Analytes were separated using either liquid or gas chromatography, and analysis was performed using tandem mass spectrometry (MS/MS). Achieved recoveries of fipronil and degradates in <span class="hlt">water</span> spiked to nominal concentrations of 0.1, 1, and 10 ng/L ranged from 77 ± 12 to 110 ± 18%. Method detection limits (MDLs) were as low as 0.040–0.8 ng/L. Extraction and quantitation of total fiproles at a wastewater-receiving wetland yielded concentrations in surface <span class="hlt">water</span> and <span class="hlt">pore</span> <span class="hlt">water</span> ranging from 9.9 ± 4.6 to 18.1 ± 4.6 ng/L and 9.1 ± 3.0 to 12.6 ± 2.1 ng/L, respectively. Detected concentrations were statistically indistinguishable from those determined by conventional, more laborious techniques (p > 0.2 for the three most abundant fiproles). Aside from offering time-averaged sampling capabilities for two phases simultaneously with picogram-per-liter MDLs, the novel methodology eliminates the need for <span class="hlt">water</span> and sediment transport via in situ solid phase extraction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4764808','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4764808"><span>Active Sampling Device for Determining Pollutants in Surface and <span class="hlt">Pore</span> <span class="hlt">Water</span> – the In Situ Sampler for Biphasic <span class="hlt">Water</span> Monitoring</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Supowit, Samuel D.; Roll, Isaac B.; Dang, Viet D.; Kroll, Kevin J.; Denslow, Nancy D.; Halden, Rolf U.</p> <p>2016-01-01</p> <p>We designed and evaluated an active sampling device, using as analytical targets a family of pesticides purported to contribute to honeybee colony collapse disorder. Simultaneous sampling of bulk <span class="hlt">water</span> and <span class="hlt">pore</span> <span class="hlt">water</span> was accomplished using a low-flow, multi-channel pump to deliver <span class="hlt">water</span> to an array of solid-phase extraction cartridges. Analytes were separated using either liquid or gas chromatography, and analysis was performed using tandem mass spectrometry (MS/MS). Achieved recoveries of fipronil and degradates in <span class="hlt">water</span> spiked to nominal concentrations of 0.1, 1, and 10 ng/L ranged from 77 ± 12 to 110 ± 18%. Method detection limits (MDLs) were as low as 0.040–0.8 ng/L. Extraction and quantitation of total fiproles at a wastewater-receiving wetland yielded concentrations in surface <span class="hlt">water</span> and <span class="hlt">pore</span> <span class="hlt">water</span> ranging from 9.9 ± 4.6 to 18.1 ± 4.6 ng/L and 9.1 ± 3.0 to 12.6 ± 2.1 ng/L, respectively. Detected concentrations were statistically indistinguishable from those determined by conventional, more laborious techniques (p > 0.2 for the three most abundant fiproles). Aside from offering time-averaged sampling capabilities for two phases simultaneously with picogram-per-liter MDLs, the novel methodology eliminates the need for <span class="hlt">water</span> and sediment transport via in situ solid phase extraction. PMID:26905924</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.H21B0837V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.H21B0837V"><span>Solute contributions from precipitation to the compositions of soil <span class="hlt">waters</span> in a <span class="hlt">marine</span> terrace chronosequence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vivit, D. V.; White, A. F.; Bullen, T. D.; Fitzpatrick, J.</p> <p>2009-12-01</p> <p>Solute loading of soil <span class="hlt">waters</span> by rainfall together with evapo-transpiration can increase the concentrations of various dissolved constituents. This process complicates the modeling of saturation states for the different mineral phases in the soil profile that are products of the weathering of primary minerals in the original granitic source material. The estimation of true rates of regolith weathering due to CO2 drawdown at temperate hydrogeological sites requires having soil <span class="hlt">pore</span> <span class="hlt">water</span> solute concentration data which have been corrected for solute inputs from precipitation before proceeding with chemical weathering calculations. As part of a chemical weathering study of a coastal <span class="hlt">marine</span> terrace chronosequence located in the vicinity of Wilder Ranch State Park, Santa Cruz County, CA, bulk samplers and automatic precipitation-event samplers were used at a range of sites to determine elemental concentrations as well as isotopic compositions of rainfall solutes which influence the overall compositions of the <span class="hlt">pore</span> <span class="hlt">waters</span>. Variations in rain sample chemistry correlated with precipitation intensity (see Fig. 1) are a result of solute inputs from aerosols of <span class="hlt">marine</span> and terrestrial origins. Higher isotope ratios (87Sr/86Sr), which point to radiogenic dust sources, were found in rain collected in the fall at the beginning of the rainy season while lower ratio values indicating <span class="hlt">marine</span> aerosol effects were seen in winter and spring samples. To further understand the development of solute levels in rain, the NOAA HYSPLIT particle-tracking program was used to follow the chronological progression of storm tracks during precipitation events. Subsequently, wind sensors along with the automatic rain collectors were installed in an effort to correlate high resolution wind-speed and wind-direction data with changing compositions of rain samples collected at fixed-time intervals during storm events. Wind data show that wind directions during periods of rainfall generally deviate from</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70014185','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70014185"><span>Solid-state 13C NMR studies of dissolved organic matter in <span class="hlt">pore</span> <span class="hlt">waters</span> from different depositional environments</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Orem, W.H.; Hatcher, P.G.</p> <p>1987-01-01</p> <p>Dissolved organic matter (DOM) in <span class="hlt">pore</span> <span class="hlt">waters</span> from sediments of a number of different depositional environments was isolated by ultrafiltration using membranes with a nominal molecular weight cutoff of 500. This > 500 molecular weight DOM represents 70-98% of the total DOM in these <span class="hlt">pore</span> <span class="hlt">waters</span>. We determined the gross chemical structure of this material using both solid-state 13C nuclear magnetic resonance spectroscopy and elemental analysis. Our results show that the DOM in these <span class="hlt">pore</span> <span class="hlt">waters</span> appears to exist as two major types: one type dominated by carbohydrates and paraffinic structures and the second dominated by paraffinic and aromatic structures. We suggest that the dominance of one or the other structural type of DOM in the <span class="hlt">pore</span> <span class="hlt">water</span> depends on the relative oxidizing/reducing nature of the sediments as well as the source of the detrital organic matter. Under dominantly anaerobic conditions carbohydrates in the sediments are degraded by bacteria and accumulate in the <span class="hlt">pore</span> <span class="hlt">water</span> as DOM. However, little or no degradation of lignin occurs under these conditions. In contrast, sediments thought to be predominantly aerobic in character have DOM with diminished carbohydrate and enhanced aromatic character. The aromatic structures in the DOM from these sediments are thought to arise from the degradation of lignin. The large amounts of paraffinic structures in both types of DOM may be due to the degradation of unidentified paraffinic materials in algal or bacterial remains. ?? 1987.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70038464','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70038464"><span>Toxicity of sediment <span class="hlt">pore</span> <span class="hlt">water</span> in Puget Sound (Washington, USA): a review of spatial status and temporal trends</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Long, Edward R.; Carr, R. Scott; Biedenbach, James M.; Weakland, Sandra; Partridge, Valerie; Dutch, Margaret</p> <p>2013-01-01</p> <p>Data from toxicity tests of the <span class="hlt">pore</span> <span class="hlt">water</span> extracted from Puget Sound sediments were compiled from surveys conducted from 1997 to 2009. Tests were performed on 664 samples collected throughout all of the eight monitoring regions in the Sound, an area encompassing 2,294.1 km2. Tests were performed with the gametes of the Pacific purple sea urchin, Strongylocentrotus purpuratus, to measure percent fertilization success as an indicator of relative sediment quality. Data were evaluated to determine the incidence, degree of response, geographic patterns, spatial extent, and temporal changes in toxicity. This is the first survey of this kind and magnitude in Puget Sound. In the initial round of surveys of the eight regions, 40 of 381 samples were toxic for an incidence of 10.5 %. Stations classified as toxic represented an estimated total of 107.1 km2, equivalent to 4.7 % of the total area. Percent sea urchin fertilization ranged from >100 % of the nontoxic, negative controls to 0 %. Toxicity was most prevalent and pervasive in the industrialized harbors and lowest in the deep basins. Conditions were intermediate in deep-<span class="hlt">water</span> passages, urban bays, and rural bays. A second round of testing in four regions and three selected urban bays was completed 5–10 years following the first round. The incidence and spatial extent of toxicity decreased in two of the regions and two of the bays and increased in the other two regions and the third bay; however, only the latter change was statistically significant. Both the incidence and spatial extent of toxicity were lower in the Sound than in most other US estuaries and <span class="hlt">marine</span> bays.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20153161','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20153161"><span>Mineralogy and <span class="hlt">pore</span> <span class="hlt">water</span> chemistry of a boiler ash from a MSW fluidized-bed incinerator.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bodénan, F; Guyonnet, D; Piantone, P; Blanc, P</p> <p>2010-07-01</p> <p>This paper presents an investigation of the mineralogy and <span class="hlt">pore</span> <span class="hlt">water</span> chemistry of a boiler ash sampled from a municipal solid waste fluidized-bed incinerator, subject to 18 months of dynamic leaching in a large percolation column experiment. A particular focus is on the redox behaviour of Cr(VI) in relation to metal aluminium Al(0), as chromium may represent an environmental or health hazard. The leaching behaviour and interaction between Cr(VI) and Al(0) are interpreted on the basis of mineralogical evolutions observed over the 18-month period and of saturation indices calculated with the geochemical code PhreeqC and reviewed thermodynamic data. Results of mineralogical analyses show in particular the alteration of mineral phases during leaching (e.g. quartz and metal aluminium grains), while geochemical calculations suggest equilibria of percolating fluids with respect to specific mineral phases (e.g. monohydrocalcite and aluminium hydroxide). The combination of leaching data on a large scale and mineralogical analyses document the coupled leaching behaviour of aluminium and chromium, with chromium appearing in the <span class="hlt">pore</span> fluids in its hexavalent and mobile state once metal aluminium is no longer available for chromium reduction.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21357685','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21357685"><span>Mineralogy and <span class="hlt">pore</span> <span class="hlt">water</span> chemistry of a boiler ash from a MSW fluidized-bed incinerator</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bodenan, F.; Guyonnet, D.; Piantone, P.; Blanc, P.</p> <p>2010-07-15</p> <p>This paper presents an investigation of the mineralogy and <span class="hlt">pore</span> <span class="hlt">water</span> chemistry of a boiler ash sampled from a municipal solid waste fluidized-bed incinerator, subject to 18 months of dynamic leaching in a large percolation column experiment. A particular focus is on the redox behaviour of Cr(VI) in relation to metal aluminium Al{sup 0}, as chromium may represent an environmental or health hazard. The leaching behaviour and interaction between Cr(VI) and Al{sup 0} are interpreted on the basis of mineralogical evolutions observed over the 18-month period and of saturation indices calculated with the geochemical code PhreeqC and reviewed thermodynamic data. Results of mineralogical analyses show in particular the alteration of mineral phases during leaching (e.g. quartz and metal aluminium grains), while geochemical calculations suggest equilibria of percolating fluids with respect to specific mineral phases (e.g. monohydrocalcite and aluminium hydroxide). The combination of leaching data on a large scale and mineralogical analyses document the coupled leaching behaviour of aluminium and chromium, with chromium appearing in the <span class="hlt">pore</span> fluids in its hexavalent and mobile state once metal aluminium is no longer available for chromium reduction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PhDT.......109R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PhDT.......109R"><span>Using direct measurements of submarine groundwater discharge to investigate the coupling between surface and <span class="hlt">pore</span> <span class="hlt">waters</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rapaglia, John Paul</p> <p></p> <p>Submarine groundwater discharge (SGD) and its associated impact on coastal ecosystems was investigated at the sediment-<span class="hlt">water</span> interface using diverse methods. This intercomparison of methods was the objective of a major project carried out in 5 diverse hydrogeological settings (Cockburn Sound, Australia; Donnalucata, Sicily; Shelter Island, USA; Ubatuba Bay, Brazil; and Flic-en-Flac Bay, Mauritius). Small-scale sedimentary processes were deemed very important in the control of local hydrogeological characteristics. Seepage meters were used to directly measure the flow of <span class="hlt">water</span> across the sediment-sea interface. Coincident measurements of bulk ground conductivity (BGC) were made alongside seepage meters at four of these locations. An inverse relationship between BGC and SGD allowed for the extrapolation of point measurements of SGD to larger areas using BGC data. SGD estimates made using this method compared favorably with those obtained using other techniques. Using seepage meters to measure flow rates, along with a manual drive point piezometer to measure <span class="hlt">pore</span> <span class="hlt">water</span> profiles, the coupling between <span class="hlt">pore</span> <span class="hlt">water</span> composition and advection due to SGD was investigated. The process of dispersion was found to determine both the shape and depth of salinity, nutrient, and radium profiles in the sediment. Dispersion may be controlled by biological or physical processes including the rate of advection itself, all of which change over time. Dispersion coefficients ranging from 0.02 m2d -1 to 2.8 m2d-1 were estimated from direct measurements. This data also allowed for the investigation of anthropogenic impacts on the signature of SGD in coastal lagoons. At Shelter Island, the pilings of a pier altered the flow of groundwater into the sea by piercing a confining layer and allowing for a large influx of fresh groundwater from below. In the Venice Lagoon, the difference in <span class="hlt">water</span> elevation between the lagoon and the sea has been investigated as a possible driver of SGD beneath the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24061783','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24061783"><span>Pilot-scale in situ bioremediation of HMX and RDX in soil <span class="hlt">pore</span> <span class="hlt">water</span> in Hawaii.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Payne, Zachary M; Lamichhane, Krishna M; Babcock, Roger W; Turnbull, Stephen J</p> <p>2013-10-01</p> <p>A nine-month in situ bioremediation study was conducted in Makua Military Reservation (MMR) in Oahu, Hawaii (USA) to evaluate the potential of molasses to enhance biodegradation of royal demolition explosive (RDX) and high-melting explosive (HMX) contaminated soil below the root zone. MMR has been in operation since the 1940's resulting in subsurface contamination that in some locations exceeds USEPA preliminary remediation goals for these chemicals. A molasses-<span class="hlt">water</span> mixture (1 : 40 dilution) was applied to a treatment plot and clean <span class="hlt">water</span> was applied to a control plot via seven flood irrigation events. <span class="hlt">Pore</span> <span class="hlt">water</span> samples were collected from 12 lysimeters installed at different depths in 3 boreholes in each test plot. The difference in mean concentrations of RDX in <span class="hlt">pore</span> <span class="hlt">water</span> samples from the two test plots was very highly significant (p < 0.001). The concentrations differences with depth were also very highly significant (p < 0.001) and degradation was greatly enhanced at depths from 5 to 13.5 ft. biodegradation was modeled as first order and the rate constant was 0.063 per day at 5 ft and decreased to 0.023 per day at 11 ft to 13.5 ft depth. Enhanced biodegradation of HMX was also observed in molasses treated plot samples but only at a depth of 5 ft. The difference in mean TOC concentration (surrogate for molasses) was highly significant with depth (p = 0.003) and very highly significant with treatment (p < 0.001). Mean total nitrogen concentrations also differed significantly with treatment (p < 0.001) and depth (p = 0.059). The molasses <span class="hlt">water</span> mixture had a similar infiltration rate to that of plain <span class="hlt">water</span> (average 4.12 ft per day) and reached the deepest sensor (31 ft) within 5 days of application. Most of the molasses was consumed by soil microorganisms by about 13.5 feet below ground surface and treatment of deeper depths may require greater molasses concentrations and/or more frequent flood irrigation. Use of the bioremediation method described herein</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.H33L..01B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.H33L..01B"><span><span class="hlt">Water</span>-Organic-Rock Reactions Recorded in <span class="hlt">Pores</span> in Shales from the Marcellus and Rose Hill Formations (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brantley, S. L.; Jin, L.; Rother, G.; Cole, D. R.; gu, X.; Balashov, V. N.</p> <p>2013-12-01</p> <p>The porosity of shales varies depending upon such attributes as the mineralogy, grain size, organic content, depth and duration of burial, and extent of <span class="hlt">water</span>-rock reaction. Today, shales are being exploited when they contain significant natural gas, and the connectivity of <span class="hlt">pores</span> are important toward controlling both recovery of gas after hydrofracking. In fact, the fine-scale nature of the <span class="hlt">pores</span> controls aspects of release of natural gas and brines during hydrofracturing and gas exploitation. Despite the importance of shale as a source rock for natural gas and petroleum, it remains difficult to quantify and image porosity in shales because of their fine-scale nature. We are using neutron scattering, FIB SEM, CT microtomography, and other techniques to understand <span class="hlt">pores</span> in a black (Marcellus) and a grey shale (Rose Hill formation) sampled in Pennsylvania. Samples were recovered both from outcrop and from depth in wellbores. We also report a new approach for investigating <span class="hlt">pores</span> in shales by using neutron scattering before and after removal of organic matter. <span class="hlt">Pores</span> in the two shales are observed to be isotropic (i.e. in the plane of bedding) or anisotropic (i.e. perpendicular to bedding), as expected for sediments that have been compacted after burial. Some nanometer-sized <span class="hlt">pores</span> are observed in the organic matter of the Marcellus to be spherical; other <span class="hlt">pores</span> are observed to be present in pyrite framboids and among silicate grains in that rock. We have no evidence that significant porosity is present in the organic matter in the Rose Hill formation, a relatively organic-poor shale, but <span class="hlt">pores</span> are observed between and in clay particles. We also investigate how progressive <span class="hlt">water</span>-rock reaction changes the primary porosity in the shales by investigating weathering samples. FIB SEM images document that organic matter is oxidized and removed significantly from the weathering Marcellus before the rock turns to soil, leaving behind porosity. Pyrite oxidation and dissolution</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMOS44A..08H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMOS44A..08H"><span>Sediment-<span class="hlt">pore</span> <span class="hlt">water</span> interactions controlling cementation in the NanTroSEIZE drilling transects</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hong, W.; Spinelli, G. A.; Torres, M. E.</p> <p>2012-12-01</p> <p>One goal of the Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) is to understand how changes in subducting sediment control the transition from aseismic to seismogenic behavior in subduction zones. In the sediment entering the Nankai subduction zone, dramatic changes in physical and chemical properties occur across a diagenetic boundary; they are thought to affect sediment strength and deformation. The dissolution of disseminated volcanic ash and precipitation of silica cement may be responsible for these changes in physical properties, but the mechanism controlling cementation was unclear (Spinelli et al., 2007). In this study, we used CrunchFlow (Steefel, 2009) to simulate chemical reactions and fluid flow through 1-D sediment columns at Integrated Ocean Drilling Program (IODP) sites on the incoming plate in Nankai Trough. The simulations include the thermodynamics and kinetics of sediment-<span class="hlt">water</span> interactions, advection of <span class="hlt">pore</span> <span class="hlt">water</span> and sediment due to compaction, and multi-component diffusion in an accumulating sediment column. Key reactions in the simulations are: ash dissolution, amorphous silica precipitation and dissolution, and zeolite precipitation. The rate of ash decomposition was constrained using Sr isotope data of Joseph et al. (2012). Our model reproduces the distinct diagenetic boundary observed in sediment and <span class="hlt">pore</span> <span class="hlt">water</span> chemistry, which defines two zones. Above this boundary (zone 1), dissolved and amorphous silicate contents are high and the potassium concentration remains near seawater values or gradually decreases toward the boundary. Below the boundary, both dissolved and amorphous silicate content drop rapidly, concomitant with a decrease in dissolved potassium. Our model shows that these changes in the system are driven by formation of clinoptilolite in response to changes in <span class="hlt">pore</span> fluid pH. The low pH values (<7.6) above the diagenetic boundary accelerate ash decomposition and maintain clinoptilolite slightly undersaturated. The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1514238S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1514238S"><span>Impact of long term wetting on <span class="hlt">pore</span> <span class="hlt">water</span> chemistry in a peat bog in Ontario, Canada</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schaper, Jonas; Blodau, Christian; Holger Knorr, Klaus</p> <p>2013-04-01</p> <p>Peatlands of the northern hemisphere store a remarkable amount of carbon but also contribute to global methane emissions. As large areas in the boreal and subarctic zone are considered to undergo significant climate change it is necessary to understand how these ecosystems react to altered environmental conditions. Since not only temperatures but also precipitation is likely to increase in these regions, it is of particular interest to understand the impact of raised <span class="hlt">water</span> tables and changing local hydrological flow patterns on peatlands' carbon cycle. We chose a pristine bog that was partly flooded by a reservoir lake created 60 years ago in Ontario, Canada. <span class="hlt">Water</span> management in the reservoir resulted in seasonal flooding, shifting hydrological flow patterns and vegetation gradients. The impact of partial flooding on <span class="hlt">pore</span> <span class="hlt">water</span> chemistry and DIC and CH4 concentrations were studied within surface peat layers. Samples were taken with <span class="hlt">pore</span> <span class="hlt">water</span> peepers along the vegetation- and flooding gradient. Turnover rates of DIC and methane were calculated from obtained concentration profiles and peat porosity under the assumption that transport is dominated by diffusion. Values of pH changed remarkably from 4 within the undisturbed bog part to almost 8 at the lake shore. Ca2+ and Mg2+ were the only ions that showed significant distribution patterns with readily increasing concentrations towards the lake <span class="hlt">water</span> body. CH4 and DIC concentrations also increased towards the lake and peaked in around 100 cm depth right at the shore with maximum concentrations being 2766 μmol L-1 for CH4 and 7543 μmol L-1 for DIC, respectively. Turnover rates also increased towards the shore albeit some uncertainty lies in this finding as steady state condition required for calculations were probably not established and transport was not only dominated by diffusion. Maximum CH4 production rates were modeled to be 36 nmol cm-3 d-1 and maximum DIC production was calculated to 64 nmol cm-3 d-1. Ca2</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6874662','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6874662"><span><span class="hlt">Pore</span> <span class="hlt">water</span> chemistry of an alkaline rift valley lake: Lake Turkana, Kenya</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cerling, T.E.; Johnson, T.C.; Halfman, J.D.; Lister, G.</p> <p>1985-01-01</p> <p>Lake Turkana is the largest closed basin lake in the African rift system. It has evolved through the past 5000 years to become a moderately alkaline lake. Previous mass balance argument suggest that sulfate is removed from the lake by sulfate reduction in the sediments, and that the lake is accumulating in chloride, sodium, and alkalinity. Studies of <span class="hlt">pore</span> <span class="hlt">water</span> from 12 meter cores collected in November 1984 show that sulfate is reduced in the sediment column with a net production of alkalinity. Some sodium is lost from the lake and diffuses into the sediment to maintain charge balance. At several meters depth, organic matter is destroyed by methanogenic bacteria, as shown by the high delta /sup 13/C values for dissolved inorganic carbon. Magnesium and calcium molar ratios change with depth; chloride, sodium, and alkalinity also change with depth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850024431','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850024431"><span>Microanalysis of dissolved iron and phosphate in <span class="hlt">pore</span> <span class="hlt">waters</span> of hypersaline sediment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Haddad, R.; Shaw, T.</p> <p>1985-01-01</p> <p>Diurnal fluctuations of reduced iron concentrations, expected to occur in reduced sediments in the photic zone, were studied. Iron concentration was compared to O2-H2S, a microcanalysis of sulfate reduction was performed, as well as an examination of diurnal concentration of dissolved phosphate and changes in interstitial CO2. The iron profiles suggest a strong correlation between iron remobilization and processes occurring in the light. Phosphate profiles suggest the removal of phosphate is strongly correlated with precipitation of oxidized iron in the upper 2 mm to 5 mm of the sediments. <span class="hlt">Pore</span> <span class="hlt">water</span> CO2 concentrations and carbon isotope ratios are presented. These data are from the analyses of minisediment cores collected from the 42 per mil salt pond and incubated in the laboratory under light and dark conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23722150','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23722150"><span>Plant uptake of elements in soil and <span class="hlt">pore</span> <span class="hlt">water</span>: field observations versus model assumptions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Raguž, Veronika; Jarsjö, Jerker; Grolander, Sara; Lindborg, Regina; Avila, Rodolfo</p> <p>2013-09-15</p> <p>Contaminant concentrations in various edible plant parts transfer hazardous substances from polluted areas to animals and humans. Thus, the accurate prediction of plant uptake of elements is of significant importance. The processes involved contain many interacting factors and are, as such, complex. In contrast, the most common way to currently quantify element transfer from soils into plants is relatively simple, using an empirical soil-to-plant transfer factor (TF). This practice is based on theoretical assumptions that have been previously shown to not generally be valid. Using field data on concentrations of 61 basic elements in spring barley, soil and <span class="hlt">pore</span> <span class="hlt">water</span> at four agricultural sites in mid-eastern Sweden, we quantify element-specific TFs. Our aim is to investigate to which extent observed element-specific uptake is consistent with TF model assumptions and to which extent TF's can be used to predict observed differences in concentrations between different plant parts (root, stem and ear). Results show that for most elements, plant-ear concentrations are not linearly related to bulk soil concentrations, which is congruent with previous studies. This behaviour violates a basic TF model assumption of linearity. However, substantially better linear correlations are found when weighted average element concentrations in whole plants are used for TF estimation. The highest number of linearly-behaving elements was found when relating average plant concentrations to soil <span class="hlt">pore-water</span> concentrations. In contrast to other elements, essential elements (micronutrients and macronutrients) exhibited relatively small differences in concentration between different plant parts. Generally, the TF model was shown to work reasonably well for micronutrients, whereas it did not for macronutrients. The results also suggest that plant uptake of elements from sources other than the soil compartment (e.g. from air) may be non-negligible.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AtmEn.152..323Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AtmEn.152..323Y"><span>Responses of CO2 emission and <span class="hlt">pore</span> <span class="hlt">water</span> DOC concentration to soil warming and <span class="hlt">water</span> table drawdown in Zoige Peatlands</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Gang; Wang, Mei; Chen, Huai; Liu, Liangfeng; Wu, Ning; Zhu, Dan; Tian, Jianqing; Peng, Changhui; Zhu, Qiuan; He, Yixin</p> <p>2017-03-01</p> <p>Peatlands in Zoige Plateau contains more than half of peatland carbon stock in China. This part of carbon is losing with climate change through dissolved organic carbon (DOC) export and carbon dioxide (CO2) emissions, both of which are vulnerable to the environmental changes, especially on the Zoige Plateau with a pace of twice the observed rate of global climate warming. This research aimed to understand how climate change including soil warming, rainfall reduction and <span class="hlt">water</span> table change affect CO2 emissions and whether the trends of changes in CO2 emission are consistent with those of <span class="hlt">pore</span> <span class="hlt">water</span> DOC concentration. A mesocosm experiment was designed to investigate the CO2 emission and <span class="hlt">pore</span> <span class="hlt">water</span> DOC during the growing seasons of 2009-2010 under scenarios of passive soil warming, 20% rainfall reduction and changes to the <span class="hlt">water</span> table levels. The results showed a positive relationship between CO2 emission and DOC concentration. For single factor effect, we found no significant relationship between <span class="hlt">water</span> table and CO2 emission or DOC concentration. However, temperature at 5 cm depth was found to have positive linear relationship with CO2 emission and DOC concentration. The combined effect of soil warming and rainfall reduction increased CO2 emission by 96.8%. It suggested that the drying and warming could stimulate potential emission of CO2. Extending this result to the entire peatland area in Zoige Plateau translates into 0.45 Tg CO2 emission per year over a growing season. These results suggested that the dryer and warmer Zoige Plateau will increase CO2 emission. We also found the contribution rate of DOC concentration to CO2 emission was increased by 12.1% in the surface layer and decreased by 13.8% in the subsurface layer with combined treatment of soil warming and rainfall reduction, which indicated that the warmer and dryer environmental conditions stimulate surface peat decomposition process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMGC51F1167S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMGC51F1167S"><span>Rare earth elements in <span class="hlt">pore</span> <span class="hlt">waters</span> from Cabo Friós western boundary upwelling system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smoak, J. M.; Silva-Filho, E. V.; Rousseau, T.; Albuquerque, A. L.; Caldeira, P. P.; Moreira, M.</p> <p>2015-12-01</p> <p>Rare earth elements (REE) are a group of reactive trace elements in aqueous media, they have a coherent chemical behavior with however a subtle and gradual shift in physicochemical properties allowing their use as tracers of sources and processes. Uncertainties on their oceanic inputs and outputs still remains [Arsouze et al., 2009; Siddall et al., 2008; Tachikawa et al., 2003]. The <span class="hlt">water</span>-sediment interface were early on identified as a relevant REE source due to the high distribution coefficient between sediments and <span class="hlt">pore</span> <span class="hlt">waters</span> [Elderfield and Sholkovitz, 1987] and substantially higher concentration then the <span class="hlt">water</span> column [Abbott et al., 2015; Haley et al., 2004; Sholkovitz et al., 1989; Soyol-Erdene and Huh, 2013]. Here we present a cross shelf transect of 4 short <span class="hlt">pore</span> <span class="hlt">waters</span> REE profiles on a 680 km2 mud bank located in the region of Cabo Frio, Brazil. This study reveals similar trends at the four sites: a REE production zone reflected by a maximum in concentration at the top of the sediment evolving with depth toward a REE consumption zone reflected by a minimum in REE concentrations. PAAS normalized patterns shows 1) a progressive depletion in LREE with depth with HREE/LREE ratios comprised between 1.1 and 1.6 in the 2 first centimeters evolving gradually to ratios comprised between 2.8 and 4.7 above 7 cm 2) A sharp gradient in negative Ce anomaly with Ce/Ce* values reaching 0.3. With maximum Nd concentrations comprised between 780 and 1200 pmol.kg and considering that seawater Nd concentrations of Brazilian shelf bottom <span class="hlt">waters</span> are comprised between 24 and 50 pmol.Kg-1 we apply the Fick´s First Law of diffusion and estimate that 340 +/- 90 nmol. m-2 Y-1 of Nd is released in the Cabo frio´s mudbank. This flux is in the same order of magnitude of recent estimates by [Abbott et al., 2015] in the slope of Oregon´s margin. Unraveling processes responsible for the REE production zone will help to refine the global REE fluxes estimates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013NIMPB.294..537H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013NIMPB.294..537H"><span>A summary of global 129I in <span class="hlt">marine</span> <span class="hlt">waters</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>He, Peng; Aldahan, A.; Possnert, G.; Hou, X. L.</p> <p>2013-01-01</p> <p>Despite the many investigations concerning the occurrence of anthropogenic iodine-129 in the atmosphere, terrestrial and <span class="hlt">marine</span> environments, there is a lack of a comprehensive collection of data on the distribution of the isotope in <span class="hlt">marine</span> <span class="hlt">waters</span>. The temporal and spatial variability of anthropogenic 129I is strongly linked to the major point sources in the Irish Sea and the English Channel and the global <span class="hlt">marine</span> spreading pathways are partly outlined from these sources. The temporal evolution is still, however, not well defined when transport and dissipation are considered in the different oceans and ocean compartments. We here summarize available published literature data on 129I temporal and spatial distribution in the global <span class="hlt">marine</span> <span class="hlt">water</span>. The results show presence of numerous data sets for the North Atlantic and Arctic Oceans where strong variability in terms of <span class="hlt">water</span> depth, time and location also occur. Scarcity of data on 129I from the Pacific, Indian and South Atlantic Oceans demonstrates gaps in the coverage of the isotope spatial extent. These shortcomings in the spatial coverage may relate to the understanding that the anthropogenic 129I signal will take a long time to be transported, if at all, from the North Atlantic into other oceans. Data from recent expeditions in the Southern oceans and the Geotraces ocean profiling will reveal additional information about 129I distribution in the <span class="hlt">marine</span> <span class="hlt">waters</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/355543','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/355543"><span>Determination of acute Zn toxicity in <span class="hlt">pore</span> <span class="hlt">water</span> from soils previously treated with sewage sludge using bioluminescence assays</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chaudri, A.M.; Knight, B.P.; Barbosa-Jefferson, V.L.</p> <p>1999-06-01</p> <p>The effects of increasing concentrations of Zn and Cu in soil <span class="hlt">pore</span> <span class="hlt">water</span> from soils of a long-term sewage sludge field experiment on microbial bioluminescence were investigated. Concentrations of total soluble Zn, free Zn{sup 2+}, and soluble Cu increased sharply in soil <span class="hlt">pore</span> <span class="hlt">water</span> with increasing total soil metal concentrations above 140 mg of Zn kg{sup {minus}1} or 100 mg of Cu kg{sup {minus}1}. Two luminescence bioassays were tested, based on two bacteria (Escherichia coli and Pseudomonas fluorescens) with the lux genes encoding bacterial luminescence inserted into them. The bioluminescence response of the two microorganisms declined as total soil Zn, soil <span class="hlt">pore</span> <span class="hlt">water</span> soluble Zn, and soil <span class="hlt">pore</span> <span class="hlt">water</span> free Zn{sup 2+} concentrations increased. The EC{sub 25} values for E. coli and P. fluorescens were 1.3 {+-} 0.2 and 4.3 {+-} 0.5 mg L{sup {minus}1} on a free Zn{sup 2+} basis, respectively. The EC{sub 50} values were 2.5 {+-} 0.2 and 9.6 {+-} 0.9 mg of free Zn{sup 2+} L{sup {minus}1}, respectively. Copper had no significant effect on bioluminescence in the two assays, even at the largest soil <span class="hlt">pore</span> <span class="hlt">water</span> concentration of about 620 {micro}g L{sup {minus}1}, corresponding to a total Cu concentration in bulk soil of about 350 mg kg{sup {minus}1}. Thus, the decline in bioluminescence of the two assays was ascribed to increasing soil <span class="hlt">pore</span> <span class="hlt">water</span> free Zn{sup 2+} and not soluble Cu.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70030383','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70030383"><span>Assessing sulfate reduction and methane cycling in a high salinity <span class="hlt">pore</span> <span class="hlt">water</span> system in the northern Gulf of Mexico</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Pohlman, J.W.; Ruppel, C.; Hutchinson, D.R.; Downer, R.; Coffin, R.B.</p> <p>2008-01-01</p> <p><span class="hlt">Pore</span> <span class="hlt">waters</span> extracted from 18 piston cores obtained on and near a salt-cored bathymetric high in Keathley Canyon lease block 151 in the northern Gulf of Mexico contain elevated concentrations of chloride (up to 838 mM) and have <span class="hlt">pore</span> <span class="hlt">water</span> chemical concentration profiles that exhibit extensive departures (concavity) from steady-state (linear) diffusive equilibrium with depth. Minimum ??13C dissolved inorganic carbon (DIC) values of -55.9??? to -64.8??? at the sulfate-methane transition (SMT) strongly suggest active anaerobic oxidation of methane (AOM) throughout the study region. However, the nonlinear <span class="hlt">pore</span> <span class="hlt">water</span> chemistry-depth profiles make it impossible to determine the vertical extent of active AOM or the potential role of alternate sulfate reduction pathways. Here we utilize the conservative (non-reactive) nature of dissolved chloride to differentiate the effects of biogeochemical activity (e.g., AOM and/or organoclastic sulfate reduction) relative to physical mixing in high salinity Keathley Canyon sediments. In most cases, the DIC and sulfate concentrations in <span class="hlt">pore</span> <span class="hlt">waters</span> are consistent with a conservative mixing model that uses chloride concentrations at the seafloor and the SMT as endmembers. Conservative mixing of <span class="hlt">pore</span> <span class="hlt">water</span> constituents implies that an undetermined physical process is primarily responsible for the nonlinearity of the <span class="hlt">pore</span> <span class="hlt">water</span>-depth profiles. In limited cases where the sulfate and DIC concentrations deviated from conservative mixing between the seafloor and SMT, the ??13C-DIC mixing diagrams suggest that the excess DIC is produced from a 13C-depleted source that could only be accounted for by microbial methane, the dominant form of methane identified during this study. We conclude that AOM is the most prevalent sink for sulfate and that it occurs primarily at the SMT at this Keathley Canyon site.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PCE....36.1817S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PCE....36.1817S"><span>Testing geochemical models of bentonite <span class="hlt">pore</span> <span class="hlt">water</span> evolution against laboratory experimental data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Savage, David; Arthur, Randy; Watson, Claire; Wilson, James; Strömberg, Bo</p> <p></p> <p>The determination of a bentonite <span class="hlt">pore</span> <span class="hlt">water</span> composition and understanding its evolution with time underpins many radioactive waste disposal issues, such as buffer erosion, canister corrosion, and radionuclide solubility, sorption, and diffusion, inter alia. Previous modelling approaches have tended to ignore clay dissolution-precipitation reactions, a consequence of which is that montmorillonite is theoretically preserved indefinitely in the repository system. Here, we investigate the applicability of an alternative clay <span class="hlt">pore</span> fluid evolution model, that incorporates clay dissolution-precipitation reactions as an integral component and test it against well-characterised laboratory experimental data, where key geochemical parameters, Eh and pH, have been measured directly in compacted bentonite. Simulations have been conducted using different computer codes (Geochemist’s Workbench, PHREEQC, and QPAC) to test the applicability of this model. Thermodynamic data for the Gibb’s free energy of formation of MX-80 smectite used in the calculations were estimated using two different methods (‘Polymer’ and ‘Vieillard’ Models). Simulations of ‘end-point’ pH measurements in batch bentonite-<span class="hlt">water</span> slurry experiments showed different pH values according to the complexity of the system studied. The most complete system investigated revealed pH values were a strong function of partial pressure of carbon dioxide, with pH increasing with decreasing PCO 2 (with log PCO 2 values ranging from -3.5 to -7.5 bars produced pH values ranging from 7.9 to 9.6). A second set of calculations investigated disequilibrium between clay and <span class="hlt">pore</span> fluid in laboratory squeezing cell tests involving pure <span class="hlt">water</span> (pH = 9.0) or a 1 M NaOH solution (pH = 12.1). Simulations carried out for 100 days (the same timescale as the experiments) showed that smectite remained far from equilibrium throughout, and that the lowering of pH due to smectite hydrolysis was trivial. However, extending the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFM.G51A0940B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.G51A0940B"><span>A Mechanism for Seismically Induced <span class="hlt">Pore</span> Pressure Changes Inferred from High Frequency <span class="hlt">Water</span> Well Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brodsky, E. E.; Roeloffs, E.; Woodcock, D.; Gall, I.; Manga, M.</p> <p>2002-12-01</p> <p>Earthquakes can produce <span class="hlt">water</span> level changes in certain distant wells orders of magnitude larger than can be explained by static stress changes. The redistribution of <span class="hlt">pore</span> pressure can generate crustal deformation and perhaps even trigger seismicity. Some studies suggest that earthquakes induce permeability increases or other aquifer property changes. Standard hydrogeological methods do not continuously measure aquifer properties therefore it is difficult to monitor the inferred variations. We developed a new method to measure aquifer properties over short times by combining high-sample rate <span class="hlt">water</span> level data (1 sps) and seismic data for a site near Grants Pass Oregon. The new method motivates a new model in which the seismic waves remove transient barriers of sediment in a fracture. Pumping test data for the site is well-modeled by a single, infinitesimally thin square planar fracture embedded in a unbounded, homogeneous and isotropic confined aquifer. For this geometry, the amplification factor χ, defined as the ratio of the <span class="hlt">water</span> level amplitude to the ground velocity, as a function of frequency f is \\[ χ = A(\</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=65284&keyword=teaching+AND+english&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=79984471&CFTOKEN=99160933','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=65284&keyword=teaching+AND+english&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=79984471&CFTOKEN=99160933"><span>DEVELOPMENT OF <span class="hlt">MARINE</span> <span class="hlt">WATER</span> QUALITY CRITERIA</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>The U.S. Environmental Protectional Agency has developed guidelines for deriving numerical national <span class="hlt">water</span> quality criteria for the protection of aquatic organisms and their uses. These guidelines provide the method for deriving <span class="hlt">water</span> quality criteria, including minimum data base...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JSCGE..67..464Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JSCGE..67..464Y"><span>MONITORING OF <span class="hlt">PORE</span> <span class="hlt">WATER</span> PRESSURE AND <span class="hlt">WATER</span> CONTENT AROUND A HORIZONTAL DRIFT THROUGH EXCAVATION - MEASUREMENT AT THE 140m GALLERY IN THE HORONOBE URL -</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yabuuchi, Satoshi; Kunimaru, Takanori; Kishi, Atsuyasu; Komatsu, Mitsuru</p> <p></p> <p>Japan Atomic Energy Agency has been conducting the Horonobe Underground Research Laboratory (URL) project in Horonobe, Hokkaido, as a part of the research and development program on geological disposal of high-level radioactive waste. <span class="hlt">Pore</span> <span class="hlt">water</span> pressure and <span class="hlt">water</span> content around a horizontal drift in the URL have been monitored for over 18 months since before the drift excavation was started. During the drift excavation, both <span class="hlt">pore</span> <span class="hlt">water</span> pressure and <span class="hlt">water</span> content were decreasing. <span class="hlt">Pore</span> <span class="hlt">water</span> pressure has been still positive though it continued to decrease with its gradient gradually smaller after excavation, while <span class="hlt">water</span> content turned to increase about 6 months after the completion of the excavation. It turned to fall again about 5 months later. An unsaturated zone containing gases which were dissolved in groundwater may have been formed around the horizontal drift.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2012-10-04/pdf/2012-24481.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2012-10-04/pdf/2012-24481.pdf"><span>77 FR 60687 - Record of Decision for the U.S. <span class="hlt">Marine</span> Corps Basewide <span class="hlt">Water</span> Infrastructure Project at <span class="hlt">Marine</span>...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2012-10-04</p> <p>... construction, operation, and maintenance of a new Northern Advanced <span class="hlt">Water</span> Treatment plant and associated... Department of the Navy Record of Decision for the U.S. <span class="hlt">Marine</span> Corps Basewide <span class="hlt">Water</span> Infrastructure Project at... decision to upgrade and improve the Basewide <span class="hlt">water</span> infrastructure at <span class="hlt">Marine</span> Corps Base Camp...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25892066','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25892066"><span>Analysis of intracellular and extracellular microcystin variants in sediments and <span class="hlt">pore</span> <span class="hlt">waters</span> by accelerated solvent extraction and high performance liquid chromatography-tandem mass spectrometry.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zastepa, Arthur; Pick, Frances R; Blais, Jules M; Saleem, Ammar</p> <p>2015-05-04</p> <p>The fate and persistence of microcystin cyanotoxins in aquatic ecosystems remains poorly understood in part due to the lack of analytical methods for microcystins in sediments. Existing methods have been limited to the extraction of a few extracellular microcystins of similar chemistry. We developed a single analytical method, consisting of accelerated solvent extraction, hydrophilic-lipophilic balance solid phase extraction, and reversed phase high performance liquid chromatography-tandem mass spectrometry, suitable for the extraction and quantitation of both intracellular and extracellular cyanotoxins in sediments as well as <span class="hlt">pore</span> <span class="hlt">waters</span>. Recoveries of nine microcystins, representing the chemical diversity of microcystins, and nodularin (a <span class="hlt">marine</span> analogue) ranged between 75 and 98% with one, microcystin-RR (MC-RR), at 50%. Chromatographic separation of these analytes was achieved within 7.5 min and the method detection limits were between 1.1 and 2.5 ng g(-1) dry weight (dw). The robustness of the method was demonstrated on sediment cores collected from seven Canadian lakes of diverse geography and trophic states. Individual microcystin variants reached a maximum concentration of 829 ng g(-1) dw on sediment particles and 132 ng mL(-1) in <span class="hlt">pore</span> <span class="hlt">waters</span> and could be detected in sediments as deep as 41 cm (>100 years in age). MC-LR, -RR, and -LA were more often detected while MC-YR, -LY, -LF, and -LW were less common. The analytical method enabled us to estimate sediment-<span class="hlt">pore</span> <span class="hlt">water</span> distribution coefficients (K(d)), MC-RR had the highest affinity for sediment particles (log K(d)=1.3) while MC-LA had the lowest affinity (log K(d)=-0.4), partitioning mainly into <span class="hlt">pore</span> <span class="hlt">waters</span>. Our findings confirm that sediments serve as a reservoir for microcystins but suggest that some variants may diffuse into overlying <span class="hlt">water</span> thereby constituting a new route of exposure following the dissipation of toxic blooms. The method is well suited to determine the fate and persistence of different</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1812210D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1812210D"><span>Monitoring and Analysis of Transient <span class="hlt">Pore</span> <span class="hlt">Water</span> Pressures in Large Suspended Rock Slides near Poschiavo, CH</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>de Palézieux, Larissa; Loew, Simon; Zwahlen, Peter</p> <p>2016-04-01</p> <p>Many mountain slopes in the Alps exhibit large compound rock slides or Deep Seated Gravitational Slope Deformations. Due to the basal rupture plane geometry and the cumulative displacement magnitude such landslide bodies are often strongly deformed, highly fractured and - at least locally - very permeable. This can lead to high infiltration rates and low phreatic groundwater tables. This is also the situation in the studied mountain slopes southwest of Poschiavo, where large suspended rockslides occur, with very little surface runoff at high elevations, and torrents developing only at the elevation of the basal rupture planes. Below the landslide toes, at altitudes below ca. 1700 m a.s.l., groundwater appears forming spring lines or distributed spring clusters. Within the scope of the design of a hydropower pump storage plant in the Poschiavo valley by Lagobianco SA (Repower AG), numerous cored and deep boreholes (of 50 to 300 m depth) have been drilled along the planned pressure tunnel alignement at elevations ranging from 963 to 2538 m a.s.l. in the years 2010 and 2012. In several boreholes Lugeon and transient pressure tests were executed and <span class="hlt">pore</span> <span class="hlt">water</span> pressure sensors installed in short monitoring sections at various depths. Most of these boreholes intersect deep rockslides in crystalline rocks and limestones, showing highly fragmented rock masses and cohesionless cataclastic shear zones of several tens of meters thickness. This study explores these borehole observations in landslides and adjacent stable slopes and links them to the general hydrologic and hydrogeologic framework. The analysis of the <span class="hlt">pore</span> <span class="hlt">water</span> pressure data shows significant variability in seasonal trends and short-term events (from snow melt and summer rain storms) and remarkable pressure differences over short horizontal and vertical distances. This reflects rock mass damage within landslide bodies and important sealing horizons at their base. Based on <span class="hlt">water</span> balances, the estimated effective</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.7687R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.7687R"><span><span class="hlt">Marine</span> <span class="hlt">water</span> quality under climate change conditions/scenarios</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rizzi, Jonathan; Torresan, Silvia; Critto, Andrea; Zabeo, Alex; Brigolin, Daniele; Carniel, Sandro; Pastres, Roberto; Marcomini, Antonio</p> <p>2016-04-01</p> <p>The increase of sea temperature and the changes in <span class="hlt">marine</span> currents are generating impacts on coastal <span class="hlt">waters</span> such as changes in <span class="hlt">water</span> biogeochemical and physical parameters (e.g. primary production, pH, salinity) leading to progressive degradation of the <span class="hlt">marine</span> environment. With the main aim of analysing the potential impacts of climate change on coastal <span class="hlt">water</span> quality, a Regional Risk Assessment (RRA) methodology was developed and applied to coastal <span class="hlt">marine</span> <span class="hlt">waters</span> of the North Adriatic (i.e. coastal <span class="hlt">water</span> bodies of the Veneto and Friuli Venezia Giulia regions, Italy). RRA integrates the outputs of regional models providing information on macronutrients (i.e. dissolved inorganic nitrogen e reactive phosphorus), dissolved oxygen, pH, salinity and temperature, etc., under future climate change scenarios with site-specific environmental and socio-economic indicators (e.g. biotic index, presence and extension of seagrasses, presence of aquaculture). The presented approach uses Geographic Information Systems to manage, analyse, and visualize data and employs Multi-Criteria Decision Analysis for the integration of stakeholders preferences and experts judgments into the evaluation process. RRA outputs are hazard, exposure, vulnerability, risk and damage maps useful for the identification and prioritization of hot-spot areas and vulnerable targets in the considered region. Therefore, the main aim of this contribution is to apply the RRA methodology to integrate, visualize, and rank according to spatial distribution, physical and chemical data concerning the coastal <span class="hlt">waters</span> of the North Adriatic Sea in order to predict possible changes of the actual <span class="hlt">water</span> quality.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23246660','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23246660"><span>Relationships of surface <span class="hlt">water</span>, <span class="hlt">pore</span> <span class="hlt">water</span>, and sediment chemistry in wetlands adjacent to Great Salt Lake, Utah, and potential impacts on plant community health.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Carling, Gregory T; Richards, David C; Hoven, Heidi; Miller, Theron; Fernandez, Diego P; Rudd, Abigail; Pazmino, Eddy; Johnson, William P</p> <p>2013-01-15</p> <p>We collected surface <span class="hlt">water</span>, <span class="hlt">pore</span> <span class="hlt">water</span>, and sediment samples at five impounded wetlands adjacent to Great Salt Lake, Utah, during 2010 and 2011 in order to characterize pond chemistry and to compare chemistry with plant community health metrics. We also collected <span class="hlt">pore</span> <span class="hlt">water</span> and sediment samples along multiple transects at two sheet flow wetlands during 2011 to investigate a potential link between wetland chemistry and encroachment of invasive emergent plant species. Samples were analyzed for a suite of trace and major elements, nutrients, and relevant field parameters. The extensive sampling campaign provides a broad assessment of Great Salt Lake wetlands, including a range of conditions from reference to highly degraded. We used nonmetric multidimensional scaling (NMS) to characterize the wetland sites based on the multiple parameters measured in surface <span class="hlt">water</span>, <span class="hlt">pore</span> <span class="hlt">water</span>, and sediment. NMS results showed that the impounded wetlands fall along a gradient of high salinity/low trace element concentrations to low salinity/high trace element concentrations, whereas the sheet flow wetlands have both elevated salinity and high trace element concentrations, reflecting either different sources of element loading or different biogeochemical/hydrological processes operating within the wetlands. Other geochemical distinctions were found among the wetlands, including Fe-reducing conditions at two sites and sulfate-reducing conditions at the remaining sites. Plant community health metrics in the impounded wetlands showed negative correlations with specific metal concentrations in sediment (THg, Cu, Zn, Cd, Sb, Pb, Ag, Tl), and negative correlations with nutrient concentrations in surface <span class="hlt">water</span> (nitrite, phosphate, nitrate). In the sheet flow wetlands, invasive plant species were inversely correlated with <span class="hlt">pore</span> <span class="hlt">water</span> salinity. These results indicate that sediment and <span class="hlt">pore</span> <span class="hlt">water</span> chemistry play an important role in wetland plant community health, and that monitoring and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70021295','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70021295"><span>A mini drivepoint sampler for measuring <span class="hlt">pore</span> <span class="hlt">water</span> solute concentrations in the hyporheic zone of sand-bottom streams</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Duff, J.H.; Murphy, F.; Fuller, C.C.; Triska, F.J.</p> <p>1998-01-01</p> <p>A new method for collecting <span class="hlt">pore-water</span> samples in sand and gravel streambeds is presented. We developed a mini drivepoint solution sampling (MINIPOINT) technique to collect <span class="hlt">pore-water</span> samples at 2.5-cm vertical resolution. The sampler consisted of six small-diameter stainless steel drivepoints arranged in a 10-cm-diameter circular array. In a simple procedure, the sampler was installed in the streambed to preset drivepoint depths of 2.5, 5.0, 7.5, 10.0, 12.5, and 15.0 cm. Sampler performance was evaluated in the Shingobee River, Minnesota, and Pinal Creek, Arizona, by measuring the vertical gradient of chloride concentration in <span class="hlt">pore</span> <span class="hlt">water</span> beneath the streambed that was established by the uninterrupted injection to the stream for 3 d. <span class="hlt">Pore-water</span> samples were withdrawn from all drivepoints simultaneously. In the first evaluation, the vertical chloride gradient was unchanged at withdrawal rates between 0.3 and 4.0 ml min-1 but was disturbed at higher rates. In the second evaluation, up to 70 ml of <span class="hlt">pore</span> <span class="hlt">water</span> was withdrawn from each drivepoint at a withdrawal rate of 2.5 ml min-1 without disturbing the vertical chloride gradient. Background concentrations of other solutes were also determined with MINIPOINT sampling. Steep vertical gradients were present for biologically reactive solutes such as DO, NH4/+, NO3/-, and dissolved organic C in the top 20 cm of the streambed. These detailed solute profiles in the hyporheic zone could not have been determined without a method for close interval vertical sampling that does not disturb natural hydrologic mixing between stream <span class="hlt">water</span> and groundwater.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26802565','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26802565"><span>Concentrations, diffusive fluxes and toxicity of heavy metals in <span class="hlt">pore</span> <span class="hlt">water</span> of the Fuyang River, Haihe Basin.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tang, Wenzhong; Duan, Shenghui; Shan, Baoqing; Zhang, Hong; Zhang, Wenqiang; Zhao, Yu; Zhang, Chao</p> <p>2016-05-01</p> <p>While the concentrations of heavy metals in <span class="hlt">pore</span> <span class="hlt">water</span> provide important information about their bioavailability, to date few studies have focused on this topic. In this study, <span class="hlt">pore</span> <span class="hlt">water</span> in river sediments collected from nine sampling sites (S1-S9) was examined to determine the concentrations, fluxes, and toxicity of heavy metals in the Fuyang River. The results showed that the average concentrations of Cr, Ni, Cu, As, Zn, and Pb in <span class="hlt">pore</span> <span class="hlt">water</span> were 17.06, 15.97, 20.93, 19.08, 43.72, and 0.56μgL(-1), respectively; these concentrations varied as the <span class="hlt">pore</span> <span class="hlt">water</span> depth increased. The diffusive fluxes of Cr, Ni, Cu, As, Zn, and Pb were in the following range: (-0.37) to 3.17, (-1.37) to 2.63, (-4.61) to 3.44, 0.17-6.02, (-180.26) to 7.51, and (-0.92) to (-0.29)μg(m(2)day)(-1), respectively. There was a potential risk of toxicity from Cu to aquatic organisms, as indicated by a value of the Interstitial <span class="hlt">Water</span> Criteria Toxic Units that exceeded 1.0. Values of the Nemeraw Index were 2.06, 0.48, 0.11, 0.20, 1.11, 1.03, 0.99, 0.88, and 0.89 from S1 to S9, respectively. Only S1 was moderately polluted by heavy metals in <span class="hlt">pore</span> <span class="hlt">water</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/367433','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/367433"><span>Development of a toxicity-based fractionation approach for the identification of phototoxic PAHs in <span class="hlt">pore</span> <span class="hlt">water</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kosian, P.A.; Makynen, E.A.; Ankley, G.T.; Monson, P.D.</p> <p>1995-12-31</p> <p>Environmental matrices often contain complex mixtures of chemical compounds, however, typically only a few chemicals are responsible for observed toxicity. To determine those chemicals responsible for toxicity, a toxicity-based fractionation technique coupled with gas chromatography/mass spectrometry (GC/MS) has been used for the isolation and identification of nonpolar toxicants in aqueous samples. In this study, this technique was modified to separate and identify polycyclic aromatic hydrocarbons (PAHs) responsible for phototoxicity in <span class="hlt">pore</span> <span class="hlt">water</span>. Whole <span class="hlt">pore</span> <span class="hlt">water</span>, obtained from sediments collected near an oil refinery discharge site, was found to be toxic to Lumbriculus variegatus in the presence of ultraviolet (UV) light. Solid phase extraction disks and high pressure liquid chromatography were used, in conjunction with toxicity tests with L. variegatus, to extract and fractionate phototoxic chemicals from the <span class="hlt">pore</span> <span class="hlt">water</span>. GC/MS analysis was performed on the toxic fractions and a tentative list of compound identifications were made based on interpretation of mass spectra and elution information from the chromatographic separation. The compounds identified include PAHs and substituted PAHs that are known or predicted to be phototoxic in the presence of UV light. The results show that a modified toxicity-based fractionation approach can be successfully applied to identify phototoxic PAHs in sediment <span class="hlt">pore</span> <span class="hlt">water</span> and therefore used in the assessment of contaminated sediments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16678886','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16678886"><span>The impact of sampling techniques on soil <span class="hlt">pore</span> <span class="hlt">water</span> carbon measurements of an Icelandic Histic Andosol.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sigfusson, Bergur; Paton, Graeme I; Gislason, Sigurdur R</p> <p>2006-10-01</p> <p>The carbon in soil <span class="hlt">pore</span> <span class="hlt">water</span> from a Histic Andosol from Western Iceland was studied at three different scales; in the field, in undisturbed outdoor mesocosms and in laboratory repacked microcosms. <span class="hlt">Pore</span> <span class="hlt">water</span> was extracted using suction cup lysimeters and hollow-fibre tube sampler devices (Rhizon samplers). There were significant differences in all measured variables, dissolved inorganic carbon (DIC), dissolved organic carbon (DOC) and pH values between the scales of the experiment. Gaseous constituents of soil solution and pH were more susceptible to changes in scale and the type of sampling devices used. Dissolved inorganic carbon concentrations did not differ significantly between field and mesocosm solutions but where up to 14 times lower in microcosms compared to mesocosms solutions. Rhizon samplers yielded solutions with up to 4.7 times higher DIC concentrations than porous cup lysimeters. Mesocosm surface horizon DOC concentrations were 20 and 2 times higher than in field and microcosms respectively. There was difference in DOC concentration between sampling methods (up to 8 times higher in suction cups than rhizon samplers) above 50 cm depth. Soil solution pH values did not differ between field and mesocosms and mesocosms and microcosms respectively down to 80 cm depth. Direct comparison between field and microcosms was not possible due to the nature of sampling devices. Soil solutions sampled with Rhizon samplers yielded lower pH values (up to 1.3 pH units) than those sampled with suction cups. Twenty percent of annually bound organic carbon at the soils surface under field conditions was lost by leaching of DOC and through decomposition to DIC in disturbed non-vegetated microcosms. This percentage increased to 38% in undisturbed vegetated mesocosms highlighting the importance of surface vegetation in importing carbon to soils. Increased influx of nutrients will increase growth and photosynthesis but decrease carbon sequestration in near surface horizons</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5181194','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5181194"><span>The lipid geochemistry of interstitial <span class="hlt">waters</span> of recent <span class="hlt">marine</span> sediments</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Saliot, A.; Brault, M.; Boussuge, C. )</p> <p>1988-04-01</p> <p>To elucidate the nature of biogeochemical processes occurring at the <span class="hlt">water</span>-sediment interface, the authors have analyzed fatty acids, n-alkanes and sterols contained in interstitial <span class="hlt">waters</span> collected from oxic and anoxic <span class="hlt">marine</span> sediments in the eastern and western intertropical Atlantic Ocean and in the Arabian Sea. Lipid concentrations in interstitial <span class="hlt">waters</span> vary widely and are generally much higher than concentrations encountered in the overlying sea <span class="hlt">water</span>. Higher concentrations in interstitial <span class="hlt">water</span> are observed in environments favorable for organic input and preservation of the organic matter in the <span class="hlt">water</span> column and in the surficial sediment. The analysis of biogeochemical markers in the various media of occurrence of the organic matter such as sea <span class="hlt">water</span>, suspended particles, settling particles and sediment is discussed in terms of differences existing between these media and bio-transformations of the organic matter at the <span class="hlt">water</span>-sediment interface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19760039151&hterms=Seismic+waves&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DSeismic%2Bwaves','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19760039151&hterms=Seismic+waves&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DSeismic%2Bwaves"><span>The effects of pressure, temperature, and <span class="hlt">pore</span> <span class="hlt">water</span> on velocities in Westerly granite. [for seismic wave propagation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Spencer, J. W., Jr.; Nur, A. M.</p> <p>1976-01-01</p> <p>A description is presented of an experimental assembly which has been developed to conduct concurrent measurements of compressional and shear wave velocities in rocks at high temperatures and confining pressures and with independent control of the <span class="hlt">pore</span> pressure. The apparatus was used in studies of the joint effects of temperature, external confining pressure, and internal <span class="hlt">pore</span> <span class="hlt">water</span> on sonic velocities in Westerly granite. It was found that at a given temperature, confining pressure has a larger accelerating effect on compressional waves in dry rock, whereas at a given confining pressure, temperature has a larger retarding effect on shear waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12714300','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12714300"><span>Chemical analyses of <span class="hlt">pore</span> <span class="hlt">water</span> from boreholes USW SD-6 and USW WT-24, Yucca Mountain, Nevada.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yang, In C; Peterman, Zell E; Scofield, Kevin M</p> <p>2003-01-01</p> <p>Analyses of <span class="hlt">pore</span> <span class="hlt">water</span> extracted from cores of boreholes USW SD-6 in the central part and USW WT-24 in the northern part of Yucca Mountain, Nevada, show significant vertical and lateral variations in dissolved-ion concentrations. Analyses of samples of only a few milliliters of <span class="hlt">pore</span> <span class="hlt">water</span> extracted by uniaxial or triaxial compression and by ultracentrifugation methods from adjacent core samples are generally in agreement, within the analytical error of 10% to 15%. However, the values of silica for <span class="hlt">water</span> obtained by ultracentrifugation are consistently lower than values for <span class="hlt">water</span> obtained by compression. The larger concentrations probably are due to localized pressure solution of silicate minerals during compression. The shallower <span class="hlt">water</span> from core in borehole USW SD-6 was extracted from nonwelded units collectively referred to as the Paintbrush Tuff nonwelded (PTn). The deeper <span class="hlt">water</span> was from core in both boreholes USW SD-6 and USW WT-24 in the nonwelded units referred to as the Calico Hills nonwelded (CHn). Significant differences in mean dissolved-ion concentrations in <span class="hlt">pore</span> <span class="hlt">water</span> between the PTn and CHn are (1) decreases in Ca, Mg, SO(4), and NO(3) and (2) increases in HCO(3) and (Na+K)/(Ca+Mg) ratios. The decrease in NO(3) and the increase in HCO(3) could be the result of denitrification through the oxidation of organic matter. The decrease in Ca and associated increase in (Na+K)/(Ca+Mg) is the result of ion exchange with zeolites in the CHn in borehole USW WT-24. This effect is not nearly as pronounced in borehole USW SD-6, probably reflecting a smaller amount of zeolitization of the CHn in USW SD-6. Geochemical calculations using the PHREEQC code indicate that the <span class="hlt">pore</span> <span class="hlt">water</span> from both boreholes USW SD-6 and USW WT-24 is uniformly undersaturated in anhydrite, gypsum, and amorphous silica, but supersaturated in quartz and chalcedony. The saturation of calcite, aragonite, sepiolite, and dolomite is more variable from sample to sample.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18688535','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18688535"><span>Melting behavior of <span class="hlt">water</span> in cylindrical <span class="hlt">pores</span>: carbon nanotubes and silica glasses.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sliwinska-Bartkowiak, M; Jazdzewska, M; Huang, L L; Gubbins, K E</p> <p>2008-08-28</p> <p>We report a study of the effects of confinement in multi-walled carbon nanotubes and mesoporous silica glasses (SBA-15) on the solid structure and melting of both H(2)O and D(2)O ice, using differential scanning calorimetry, dielectric relaxation spectroscopy, and neutron diffraction. Multi-walled nanotubes of 2.4, 3.9 and 10 nm are studied, and the SBA-15 studied has <span class="hlt">pores</span> of mean diameter 3.9 nm; temperatures ranging from approximately 110 to 290 K were studied. We find that the melting point is depressed relative to the bulk <span class="hlt">water</span> for all systems studied, with the depression being greater in the case of the silica mesopores. These results are shown to be consistent with molecular simulation studies of freezing in silica and carbon materials. The neutron diffraction data show that the cubic phase of ice is stabilized by the confinement in carbon nanotubes, as well as in silica mesopores, and persists up to temperatures of about 240 K, above which there is a transition to the hexagonal ice structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H51A0561Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H51A0561Z"><span>Interaction of Ammonia Gas with Sediments and <span class="hlt">Pore</span> <span class="hlt">Water</span> and Induced Uranium Immobilization under Vadose Zone Conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhong, L.; Szecsody, J. E.; Truex, M. J.</p> <p>2014-12-01</p> <p>Preliminary studies have demonstrated the potential of ammonia gas (NH3) treatment on contaminated sediment as a vadose zone uranium remediation approach. In this work, we conducted batch, column, and flow wedge experiments to study the ammonia gas transport and interaction with sediments and <span class="hlt">pore</span> <span class="hlt">water</span>. The uranium immobilization effectiveness of the ammonia gas treatment technology was also evaluated. Ammonia gas quickly partitions into sediment <span class="hlt">pore</span> <span class="hlt">water</span> and significantly increases the pH (up to ~13.2) and the electrical conductivity (EC). The rate and range of the increase in both pH and EC are dependent on the ammonia concentration in the gas and the <span class="hlt">pore</span> <span class="hlt">water</span> content and chemistry. The pH and EC changes follow a similar pattern. During an ammonia gas injection into a heterogeneous system, it was observed that the NH3 front proceeded faster in layers of lower <span class="hlt">water</span> content compared to the same sediment layers of higher <span class="hlt">water</span> content. Elevated pH values (11 to 13.2) initially resulted from the NH3 gas partitioning into the <span class="hlt">pore</span> <span class="hlt">water</span> was buffered down to ~ 9 after 7 months of sediment exposure to the air. The rate of NH3 diffusion in sediment is a function of the <span class="hlt">water</span> content in the sediment. Higher cation/anion concentrations during the ammonia gas treatment indicated mineral dissolution due to pH increase, while lower ionic concentrations after the pH buffering revealed significant mineral precipitation. This precipitation incorporates uranium into mineral structures or provides a coating to uranium minerals, therefore achieving uranium immobilization. Treatment with 5% v/v NH3 gas for one week followed by three weeks buffering resulted in a 75% reduction in the mobile uranium mass. After 2 to 12 months of treatment, the immobile phase of uranium mass increased by up to 2.3 times.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23029086','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23029086"><span>The influence of sulphate deposition on the seasonal variation of peat <span class="hlt">pore</span> <span class="hlt">water</span> methyl Hg in a boreal mire.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bergman, Inger; Bishop, Kevin; Tu, Qiang; Frech, Wolfgang; Åkerblom, Staffan; Nilsson, Mats</p> <p>2012-01-01</p> <p>In this paper we investigate the hypothesis that long-term sulphate (SO(4) (2-)) deposition has made peatlands a larger source of methyl mercury (MeHg) to remote boreal lakes. This was done on experimental plots at a boreal, low sedge mire where the effect of long-term addition of SO(4) (2-) on peat <span class="hlt">pore</span> <span class="hlt">water</span> MeHg concentrations was observed weekly throughout the snow-free portion of 1999. The additions of SO(4) (2-) started in 1995. The seasonal mean of the <span class="hlt">pore</span> <span class="hlt">water</span> MeHg concentrations on the plots with 17 kg ha(-1) yr(-1) of sulphur (S) addition (1.3±0.08 ng L(-1), SE; n = 44) was significantly (p<0.0001) higher than the mean MeHg concentration on the plots with 3 kg ha(-1) yr(-1) of ambient S deposition (0.6±0.02 ng L(-1), SE; n = 44). The temporal variation in <span class="hlt">pore</span> <span class="hlt">water</span> MeHg concentrations during the snow free season was larger in the S-addition plots, with an amplitude of >2 ng L(-1) compared to +/-0.5 ng L(-1) in the ambient S deposition plots. The concentrations of <span class="hlt">pore</span> <span class="hlt">water</span> MeHg in the S-addition plots were positively correlated (r(2) = 0.21; p = 0.001) to the groundwater level, with the lowest concentrations of MeHg during the period with the lowest groundwater levels. The <span class="hlt">pore</span> <span class="hlt">water</span> MeHg concentrations were not correlated to total Hg, DOC concentration or pH. The results from this study indicate that the persistently higher <span class="hlt">pore</span> <span class="hlt">water</span> concentrations of MeHg in the S-addition plots are caused by the long-term additions of SO(4) (2-) to the mire surface. Since these <span class="hlt">waters</span> are an important source of runoff, the results support the hypothesis that SO(4) (2-) deposition has increased the contribution of peatlands to MeHg in downstream aquatic systems. This would mean that the increased deposition of SO(4) (2-) in acid rain has contributed to the modern increase in the MeHg burdens of remote lakes hydrologically connected to peatlands.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27541153','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27541153"><span>Distribution, diffusive fluxes, and toxicity of heavy metals and PAHs in <span class="hlt">pore</span> <span class="hlt">water</span> profiles from the northern bays of Taihu Lake.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lei, Pei; Zhang, Hong; Shan, Baoqing; Zhang, Bozheng</p> <p>2016-11-01</p> <p><span class="hlt">Pore</span> <span class="hlt">water</span> plays a more significant role than do sediments in pollutant cycling dynamics. Also, concentrations of pollutants in <span class="hlt">pore</span> <span class="hlt">water</span> provide important information about their bioavailability or eco-toxicity; however, very few studies have focused on this topic. In this study, four duplicate sediment cores from three typical northern bays as well as the central part of Taihu Lake were collected to investigate the distribution, diffusive fluxes, and toxicity of heavy metals and polycyclic aromatic hydrocarbons (PAHs) in <span class="hlt">pore</span> <span class="hlt">water</span> profiles, which will be good in understanding the mobility and toxicity of these toxic pollutants and achieving better environmental management. The diffusive fluxes of heavy metals across the sediment-<span class="hlt">water</span> interface was estimated through Fick's First Law, and the toxicity of heavy metals and PAHs in <span class="hlt">pore</span> <span class="hlt">water</span> was assessed by applying a <span class="hlt">water</span> quality index (interstitial <span class="hlt">water</span> toxicity criteria unit, IWCTU) and a hazard index (HI), respectively. The average concentrations of Cr, Cu, Ni, Pb, and Zn in surface <span class="hlt">pore</span> <span class="hlt">water</span> were 18.8, 23.4, 12.0, 13.5, and 42.5 μg L(-1), respectively. Also, concentrations of the selected heavy metals in both overlying <span class="hlt">water</span> and <span class="hlt">pore</span> <span class="hlt">water</span> from Taihu Lake were all lower than the standard values of the environmental quality standards for surface <span class="hlt">water</span>. The concentrations as the <span class="hlt">pore</span> <span class="hlt">water</span> depth increased, and the highest detected concentrations of heavy metals were recorded between 3 and 5 cm below the sediment surface. The average diffusive fluxes of these metals were 27.3, 24.8, 7.03, 7.81, and -3.32 μg (m(2) day)(-1), respectively, indicating export from sediment into overlying <span class="hlt">water</span>, with the exception of Zn. There was a potential risk of toxicity, mainly from Pb and Cu, indicating that heavy metals in <span class="hlt">pore</span> <span class="hlt">water</span> had slight to moderate impact on sediment-dwelling organisms by values of the IWCTU and the Nemeraw index. The total PAH concentrations in <span class="hlt">pore</span> <span class="hlt">water</span> were higher than those in overlying</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26573312','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26573312"><span>Distributions, fluxes, and toxicities of heavy metals in sediment <span class="hlt">pore</span> <span class="hlt">water</span> from tributaries of the Ziya River system, northern China.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhu, Xiaolei; Shan, Baoqing; Tang, Wenzhong; Li, Shanshan; Rong, Nan</p> <p>2016-03-01</p> <p>The distributions and mobilities of metals in <span class="hlt">pore</span> <span class="hlt">water</span> strongly influence the biogeochemical processes and bioavailabilities of metals at sediment-<span class="hlt">water</span> interfaces. Heavy metal concentrations were measured in <span class="hlt">pore</span> <span class="hlt">water</span> samples from the Shaocun River (SR), the Wangyang River (WR), and the Xiao River (XR), tributaries of the Ziya River system, northern China. The aim was to assess heavy metal contamination in the system and the associated environmental risks. The mean Cd, Cr, Cu, Ni, Pb, and Zn concentrations in all three tributaries were 0.373, 57.1, 37.7, 20.4, 14.0, and 90.6 μg/L, respectively. The calculated Cd, Cr, Cu, Ni, Pb, and Zn diffusion fluxes in the rivers were -0.427 to 0.469, -71.8 to 42.5, 3.16 to 86.6, 5.29 to 14.0, 7.24 to 19.0, and -204 to 21.9 μg/(m(2) day), respectively, showing that the <span class="hlt">pore</span> <span class="hlt">water</span> was a source of most of the metals to the <span class="hlt">water</span> column. Only Cu and Pb in the XR and Cu in the WR exceeded the final chronic value recommended by the US Environmental Protection Agency, but the metals in the WR sediment could have caused toxic effects. These results are likely to be useful to the authorities responsible for sustainable river management.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA461868','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA461868"><span>Impact of a Hydrate-Based <span class="hlt">Marine</span> Desalination Technology on <span class="hlt">Marine</span> Microbiota and <span class="hlt">Water</span> Quality</span></a></p> <p><a target="_blank" href="https://publicaccess.dtic.mil/psm/api/service/search/search">DTIC Science & Technology</a></p> <p></p> <p>2006-12-27</p> <p>bacterial assemblages (Ezura et al. 1974, Rheinheimer 1977) and particularly psychrophilic <span class="hlt">marine</span> bacteria (Helmke and Weyland 1995, Morita 1976...Morita et al. 1973, Stanley and Morita 1968). The latter class of bacteria may be important in the expected deep <span class="hlt">water</span> hydrate formation zone for the...MDS technology. Bacteria change the composition of their cell membranes in response to local environmental conditions and these alterations can</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25835808','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25835808"><span>Investigation of the Effect of the Tortuous <span class="hlt">Pore</span> Structure on <span class="hlt">Water</span> Diffusion through a Polymer Film Using Lattice Boltzmann Simulations.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gebäck, Tobias; Marucci, Mariagrazia; Boissier, Catherine; Arnehed, Johan; Heintz, Alexei</p> <p>2015-04-23</p> <p>Understanding how the <span class="hlt">pore</span> structure influences the mass transport through a porous material is important in several applications, not the least in the design of polymer film coatings intended to control drug release. In this study, a polymer film made of ethyl cellulose and hydroxypropyl cellulose was investigated. The 3D structure of the films was first experimentally characterized using confocal laser scanning microscopy data and then mathematically reconstructed for the whole film thickness. Lattice Boltzmann simulations were performed to compute the effective diffusion coefficient of <span class="hlt">water</span> in the film and the results were compared to experimental data. The local porosities and <span class="hlt">pore</span> sizes were also analyzed to determine how the properties of the internal film structure affect the <span class="hlt">water</span> effective diffusion coefficient. The results show that the top part of the film has lower porosity, lower <span class="hlt">pore</span> size, and lower connectivity, which results in a much lower effective diffusion coefficient in this part, largely determining the diffusion rate through the entire film. Furthermore, the local effective diffusion coefficients were not proportional to the local film porosity, indicating that the results cannot be explained by a single tortuosity factor. In summary, the proposed methodology of combining microscopy data, mass transport simulations, and <span class="hlt">pore</span> space analysis can give valuable insights on how the film structure affects the mass transport through the film.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1166855','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1166855"><span><span class="hlt">Pore</span>-scale simulation of liquid CO2 displacement of <span class="hlt">water</span> using a two-phase lattice Boltzmann model</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Liu, Haihu; Valocchi, Albert J.; Werth, Charles J.; Kang, Oinjun; Oostrom, Martinus</p> <p>2014-11-01</p> <p>A lattice Boltzmann color-fluid model, which was recently proposed by Liu et al. [H. Liu, A.J. Valocchi, and Q. Kang. Three-dimensional lattice Boltzmann model for immiscible two-phase flow simulations. Phys. Rev. E, 85:046309, 2012.] based on a concept of continuum surface force, is improved to simulate immiscible two-phase flows in porous media. The new improvements allow the model to account for different kinematic viscosities of both fluids and to model fluid-solid interactions. The capability and accuracy of this model is first validated by two benchmark tests: a layered two-phase flow with a viscosity ratio, and a dynamic capillary intrusion. This model is then used to simulate liquid CO2 (LCO2) displacing <span class="hlt">water</span> in a dual-permeability <span class="hlt">pore</span> network. The extent and behavior of LCO2 preferential flow (i.e., fingering) is found to depend on the capillary number (Ca), and three different displacement patterns observed in previous micromodel experiments are reproduced. The predicted variation of LCO2 saturation with Ca, as well as variation of specific interfacial length with LCO2 saturation, are both in good agreement with the experimental observations. To understand the effect of heterogeneity on <span class="hlt">pore</span>-scale displacement, we also simulate LCO2 displacing <span class="hlt">water</span> in a randomly heterogeneous <span class="hlt">pore</span> network, which has the same size and porosity as the dual-permeability <span class="hlt">pore</span> network. In comparison to the dual-permeability case, the transition from capillary fingering to viscous fingering occurs at a higher Ca, and LCO2 saturation is higher at low Ca but lower at high Ca. In either <span class="hlt">pore</span> network, the LCO2-<span class="hlt">water</span> specific interfacial length is found to obey a power-law dependence on LCO2 saturation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2011/1078/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2011/1078/"><span>Sediment <span class="hlt">pore-water</span> toxicity test results and preliminary toxicity identification of post-landfall <span class="hlt">pore-water</span> samples collected following the Deepwater Horizon oil release, Gulf of Mexico, 2010</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Biedenbach, James M.; Carr, Robert S.</p> <p>2011-01-01</p> <p><span class="hlt">Pore</span> <span class="hlt">water</span> from coastal beach and marsh sediments from the northern Gulf of Mexico, pre- and post-landfall of the Deepwater Horizon oil release, were collected and evaluated for toxicity with the sea urchin fertilization and embryological development assays. There were 17 pre-landfall samples and 49 post-landfall samples tested using both assays. Toxicity was determined in four pre-landfall sites and in seven post-landfall sites in one or both assays as compared to a known reference sediment <span class="hlt">pore-water</span> sample collected in Aransas Bay, Texas. Further analysis and testing of five of the post-landfall toxic samples utilizing Toxicity Identification Evaluation techniques indicated that ammonia, and to a lesser extent metals, contributed to most, if not all, of the observed toxicity in four of the five samples. Results of one sample (MS-39) indicated evidence that ammonia, metals, and non-ionic organics were contributing to the observed toxicity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.9896H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.9896H"><span>Geochemical changes in <span class="hlt">pore</span> <span class="hlt">water</span> and reservoir rock due to CO2 injection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huq, Farhana; Blum, Philipp; Nowak, Marcus; Haderlein, Stefan; Grathwohl, Peter</p> <p>2010-05-01</p> <p>In response to current global warming, carbon capture and storage has been identified as one of the promising option. Thus, it can be an interim solution that is indeed a bridge to the future renewable energy without altering the present mode of energy consumption. Although large natural CO2 sinks are terrestrial eco-system and oceans, geological media or more specifically large sedimentary basins are now the most feasible options for carbon sequestration. At the study site, a former gas field (Altmark), which is located in the South of the Northeast German Basin, CO2 is planned to be injected into the reservoir with high pressure (> 50 bar) and temperature (125°C). Afterwards, CO2 dissolves into the <span class="hlt">pore</span> <span class="hlt">water</span> leading to acidification and follow up reactions such as dissolution/precipitation, which potentially change the porosity-permeability of the reservoir and the wetting properties of the mineral surfaces. The Altmark site was chosen due to its large storage capacity, well explored reservoir, high seal integrity due to the presence of massive salt layer (cap rock) and existing infrastructure required for enhanced gas recovery. The main objective of the current study is to quantify the CO2 trapping in aqueous solution under in situ reservoir condition. Therefore, it is necessary to investigate the geochemical changes in fluid composition due to dissolution of minerals under controlled laboratory conditions and to quantify the concentrations of complexing agents that might influence the concentration of total dissolved CO2 in aqueous solution over time. To observe these geochemical and hydraulic changes due to the injection of CO2, a closed system (batch system) technique is developed to study the influence of salinity, temperature, pressure and kinetics on mineral reactions. In addition to the closed system, a flow through (open) autoclave system was constructed. <span class="hlt">Water</span> saturated sedimentary rock cores (e.g. from the Altmark site; 5cm long, 3cm diameter) are</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11108852','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11108852"><span>Diurnal changes in <span class="hlt">pore</span> <span class="hlt">water</span> sulfide concentrations in the seagrass Thalassia testudinum beds: the effects of seagrasses on sulfide dynamics.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lee; Dunton</p> <p>2000-12-20</p> <p>The dynamics of the seagrass-sulfide interaction were examined in relation to diel changes in sediment <span class="hlt">pore</span> <span class="hlt">water</span> sulfide concentrations in Thalassia testudinum beds and adjacent bare areas in Corpus Christi Bay and lower Laguna Madre, Texas, USA, during July 1996. <span class="hlt">Pore</span> <span class="hlt">water</span> sulfide concentrations in seagrass beds were significantly higher than in adjacent bare areas and showed strong diurnal variations; levels significantly decreased during mid-day at shallow sediment depths (0-10 cm) containing high below-ground tissue biomass and surface area. In contrast, diurnal variations in sediment sulfide concentrations were absent in adjacent bare patches, and at deeper (>10 cm) sediment depths characterized by low below-ground plant biomass or when the grasses were experimentally shaded. These observations suggest that the mid-day depressions in sulfide levels are linked to the transport of photosynthetically produced oxygen to seagrass below-ground tissues that fuels sediment sulfide oxidation. Lower sulfide concentrations in bare areas are likely a result of low sulfate reduction rates due to low organic matter available for remineralization. Further, high reoxidation rates due to rapid exchange between anoxic <span class="hlt">pore</span> <span class="hlt">water</span> and oxic overlying <span class="hlt">water</span> are probably stimulated in bare areas by higher current velocity on the sediment surface than in seagrass beds. The dynamics of <span class="hlt">pore</span> <span class="hlt">water</span> sulfides in seagrass beds suggest no toxic sulfide intrusion into below-ground tissues during photosynthetic periods and demonstrate that the sediment chemical environment is considerably modified by seagrasses. The reduced sediment sulfide levels in seagrass beds during photosynthetic periods will enhance seagrass production through reduced sulfide toxicity to seagrasses and sediment microorganisms related to the nutrient cycling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H23D0904T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H23D0904T"><span>Paleohydrological Information from Profiles in <span class="hlt">Pore</span> <span class="hlt">Water</span> of Holocene Low-Permeability Cores and Groundwater Flow Simulation, Lake Kasumigaura, Japan</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Takamoto, N.; Shimada, J.</p> <p>2014-12-01</p> <p>The paleohydrological information can become important to predict hydrological conditions in the future. In Japan, which hydrologically is characterized by relatively small catchment scales with steep relief of topography under humid temperate climatic conditions, the residence time of the groundwater should be relatively short. Thus the paleohydrological information preserved in the groundwater aquifer should also be limited compared with the continental aquifer. However, regarding groundwater in clay and silt sediments have low-permeability characteristic, archiving the paleohydrologic information at the time of deposition is expected.  Therefore, in this study, cores were drilled into Holocene clay and silt deposits (Site K-1 and Site K-2) in the Lake Kasumigaurain Japan, where the depositional rate 10,000 years ago was rapid and it has been affected strongly by sea level changes including transgression and regression. By using the obtained core samples and extracted <span class="hlt">pore</span> <span class="hlt">water</span> from the cores, paleohydrologic information was investigated, and it was tried to understand hydrologic environments at the study area during a Holocene. In addition, groundwater flow and solute transport simulation were conducted to reproduce profiles of <span class="hlt">pore</span> <span class="hlt">water</span>.  Results of investigation show that the profiles of <span class="hlt">pore</span> <span class="hlt">water</span> contents reflect sea level change and the difference in hydrological environment at that time at each site. The content of the paleo-brackish <span class="hlt">water</span> in the culmination of transgression was about 14,000 mg/l in Cl-, -13.0‰ in δD and -2.6‰ in δ18O. It is allowed better understanding paleohydrological information by studying not only inorganic chemistry contents and stable isotopes of <span class="hlt">pore</span> <span class="hlt">water</span> and also the diatom fossils and groundwater flow and solute transport simulation. We will characterize the paleohydrological information of the study area acquired by those investigations and analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26702554','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26702554"><span>Behaviour of pharmaceuticals and personal care products in constructed wetland compartments: Influent, effluent, <span class="hlt">pore</span> <span class="hlt">water</span>, substrate and plant roots.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hijosa-Valsero, María; Reyes-Contreras, Carolina; Domínguez, Carmen; Bécares, Eloy; Bayona, Josep M</p> <p>2016-02-01</p> <p>Seven mesocosm-scale constructed wetlands (CWs) with different design configurations, dealing with primary-treated urban wastewater, were assessed for the concentration, distribution and fate of ten pharmaceutical and personal care products (PPCPs) [ibuprofen, ketoprofen, naproxen, diclofenac, salicylic acid, caffeine, carbamazepine, methyl dihydrojasmonate, galaxolide and tonalide] and eight of their transformation products (TPs). Apart from influent and effluent, various CW compartments were analysed, namely, substrate, plant roots and <span class="hlt">pore</span> <span class="hlt">water</span>. PPCP content in <span class="hlt">pore</span> <span class="hlt">water</span> depended on the specific CW configuration. Macrophytes can take up PPCPs through their roots. Ibuprofen, salicylic acid, caffeine, methyl dihydrojasmonate, galaxolide and tonalide were present on the root surface with a predominance of galaxolide and caffeine in all the planted systems. Naproxen, ibuprofen, salicylic acid, methyl dihydrojasmonate, galaxolide and tonalide were uptaken by the roots. In order to better understand the removal processes, biomass measurement and biodegradability studies through the characterization of internal-external isomeric linear alkylbenzenes present on the gravel bed were performed. Three TPs namely, ibuprofen-amide, 3-ethylbenzophenone and 4-hydroxy-diclofenac were identified for the first time in wetland <span class="hlt">pore</span> <span class="hlt">water</span> and effluent <span class="hlt">water</span>, which suggests de novo formation (they were not present in the influent). Conversely, O-desmethyl-naproxen was degraded through the wetland passage since it was detected in the influent but not in the subsequent treatment stages. Biodegradation pathways are therefore suggested for most of the studied PPCPs in the assessed CWs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/15013719','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/15013719"><span>Comparison of Experimental and Model Data for the Evaporation of a Synthetic Topopah Spring Tuff <span class="hlt">Pore</span> <span class="hlt">Water</span>, Yucca Mountain, NV</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Alai, M; Sutton, M; Carroll, S</p> <p>2003-10-14</p> <p>The evaporation of a range of synthetic <span class="hlt">pore</span> <span class="hlt">water</span> solutions representative of the potential high-level-nuclear-waste repository at Yucca Mountain, NV is being investigated. The motivation of this work is to understand and predict the range of brine compositions that may contact the waste containers from evaporation of <span class="hlt">pore</span> <span class="hlt">waters</span>, because these brines could form corrosive thin films on the containers and impact their long-term integrity. A relatively complex synthetic Topopah Spring Tuff <span class="hlt">pore</span> <span class="hlt">water</span> was progressively concentrated by evaporation in a closed vessel, heated to 95 C in a series of sequential experiments. Periodic samples of the evaporating solution were taken to determine the evolving <span class="hlt">water</span> chemistry. According to chemical divide theory at 25 C and 95 C our starting solution should evolve towards a high pH carbonate brine. Results at 95 C show that this solution evolves towards a complex brine that contains about 99 mol% Na{sup +} for the cations, and 71 mol% Cl{sup -}, 18 mol% {Sigma}CO{sub 2}(aq), 9 mol% SO{sub 4}{sup 2-} for the anions. Initial modeling of the evaporating solution indicates precipitation of aragonite, halite, silica, sulfate and fluoride phases. The experiments have been used to benchmark the use of the EQ3/6 geochemical code in predicting the evolution of carbonate-rich brines during evaporation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70011623','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70011623"><span>Geochemistry of <span class="hlt">pore</span> <span class="hlt">waters</span> from Shell Oil Company drill holes on the continental slope of the northern Gulf of Mexico</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Manheim, F. T.; Bischoff, J.L.</p> <p>1969-01-01</p> <p><span class="hlt">Pore</span> <span class="hlt">waters</span> were analyzed from 6 holes drilled from M.V. "Eureka" as a part of the Shell Oil Co. deeper offshore study. The holes were drilled in <span class="hlt">water</span> depths of 600-3,000 ft. (approximately 180-550 m) and penetrated up to 1,000 ft. (300 m) of Pliocene-Recent clayey sediments. Salt and anhydrite caprock was encountered in one diapiric structure on the continental slope. Samples from holes drilled near diapiric structures showed systematic increases of <span class="hlt">pore-water</span> salinity with depth, suggestive of salt diffusion from underlying salt plugs. Anomalous concentrations of K and Br indicate that at least one plug contains late-stage evaporite minerals. Salinities approaching halite saturation were observed. Samples from holes away from diapiric structures showed little change in <span class="hlt">pore-water</span> chemistry, except for loss of SO4 and other variations attributable to early-stage diagenetic reactions with enclosing sediments. Thus, increased salt concentrations in even shallow sediments from this part of the Gulf appear to provide an indicator of salt masses at depth. ?? 1969.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/244882','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/244882"><span>Rapid toxicity screening of sediment <span class="hlt">pore</span> <span class="hlt">waters</span> using physiological and biochemical biomarkers of Daphnia magna</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Coen, W.M. De; Janssen, C.R.; Persoone, G.</p> <p>1995-12-31</p> <p>Two new rapid toxicity tests, based on ingestion activity and digestive enzyme activity of D. magna, were developed and evaluated. The ingestion activity was measured using fluorescent latex micro-beads and an automated microplate fluorimeter allowing a sensitive quantification of the feeding activity of the organisms. The activity of the digestive enzymes, 6-galactosidase, esterase and trypsin, was determined in test organism homogenates using the following fluorogenic{sup 1} and chromogenic{sup 2} substrates: 4-methylumbelliferyl-{beta}-D galactoside{sup 1}, fluorescin diacetate{sup 1} and N-Benzoyl-L-arginine-4-nitroanilide{sup 2}. Both biomarker techniques were developed to allow rapid toxicity screening on a routine basis. The toxicity of the <span class="hlt">pore</span> <span class="hlt">waters</span> of eight contaminated samples was assessed with the aid of the developed biomarker assays. Comparison of the conventional 24h EC50 values with the EC50 values obtained with the 1.5h ingestion test and the threshold concentrations of the 2h digestive enzyme tests revealed a positive correlation between the different effect concentrations. A similar correlation (r{sup 2} = 0.87) between the conventional 24h EC50 values and 1.5h EC50 values was observed in toxicity tests with pure compounds. Correlation coefficients for the relationships between the 3 enzyme effect concentrations and the 24h EC50 values ranged from 0.95 to 0.98, The positive correlations between the conventional and biomarker effect criteria, observed for both environmental samples and pure compounds, demonstrate the potential use of the developed methods as rapid toxicity screening tools.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26312406','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26312406"><span>Redox processes in <span class="hlt">pore</span> <span class="hlt">water</span> of anoxic sediments with shallow gas.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ramírez-Pérez, A M; de Blas, E; García-Gil, S</p> <p>2015-12-15</p> <p>The Ría de Vigo (NW Spain) has a high organic matter content and high rates of sedimentation. The microbial degradation of this organic matter has led to shallow gas accumulations of methane, currently distributed all along the ría. These peculiar characteristics favor the development of anoxic conditions that can determine the dynamics of iron and manganese. In order to study the role played by iron and manganese in the processes that take place in anoxic sediments with shallow gas, four gravity cores were retrieved in anoxic sediments of the Ría de Vigo in November 2012. Methane was present in two of them, below 90cm in the inner zone and below 200cm, in the outer zone. <span class="hlt">Pore</span> <span class="hlt">water</span> was collected and analyzed for vertical profiles of pH, sulfide, sulfate, iron and manganese concentrations. Sulfate concentrations decreased with depth but never reached the minimum detection limit. High sulfide concentrations were measured in all cores. The highest sulfide concentrations were found in the inner zone with methane and the lowest were in the outer zone without methane. Concentrations of iron and manganese reached maximum values in the upper layers of the sediment, decreasing with depth, except in the outer zone without gas, where iron and manganese concentration increased strongly toward the bottom of the sediment. In areas with shallow gas iron reduction, sulfate reduction and methane production processes coexist, showing that the traditional redox cascade is highly simplified and suggesting that iron may be involved in a cryptic sulfur cycle and in the oxidation of methane.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27656005','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27656005"><span>Mercury in <span class="hlt">Marine</span> and Oceanic <span class="hlt">Waters</span>-a Review.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gworek, Barbara; Bemowska-Kałabun, Olga; Kijeńska, Marta; Wrzosek-Jakubowska, Justyna</p> <p></p> <p>Mercury contamination in <span class="hlt">water</span> has been an issue to the environment and human health. In this article, mercury in <span class="hlt">marine</span> and oceanic <span class="hlt">waters</span> has been reviewed. In the aquatic environment, mercury occurs in many forms, which depend on the oxidation-reduction conditions. These forms have been briefly described in this article. Mercury concentrations in <span class="hlt">marine</span> <span class="hlt">waters</span> in the different parts of the world have been presented. In the relevant literature, two models describing the fate and behavior of mercury in saltwater reservoirs have been presented, a conceptual model which treats all the oceans as one ocean and the "ocean margin" model, providing that the ocean margins manifested themselves as the convergence of continents and oceans, covering such geological features, such as estuaries, inland seas, and the continental shelf. These two conceptual models have been summarized in the text. The mercury content in benthic sediments usually reflects is level in the <span class="hlt">water</span> reservoir, particularly in reservoirs situated in contaminated areas (mines, metallurgical plants, chemically protected crops). The concentrations of mercury and its compounds determined in the sediments in surface <span class="hlt">waters</span> in the different parts of the world have been presented. Due to the fact that the pollution caused by mercury is a serious threat for the <span class="hlt">marine</span> environment, the short paragraph about mercury bioaccumulation in aquatic organisms has been included. The cited data demonstrated a large scatter of mercury contents both between the fish species and the <span class="hlt">water</span> areas. Mathematical models, valuable tools which provide information about the possible responses of ecosystems, developed to simulate mercury emissions, both at a small scale, for local <span class="hlt">water</span> reservoirs, and at a global scale, as well as to model mercury bioaccumulation in the chain web of aquatic systems have been described.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2229644','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2229644"><span>A <span class="hlt">Marine</span> Snail Neurotoxin Shares with Scorpion Toxins a Convergent Mechanism of Blockade on the <span class="hlt">Pore</span> of Voltage-Gated K Channels</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>García, Esperanza; Scanlon, Martin; Naranjo, David</p> <p>1999-01-01</p> <p>κ-Conotoxin-PVIIA (κ-PVIIA) belongs to a family of peptides derived from a hunting <span class="hlt">marine</span> snail that targets to a wide variety of ion channels and receptors. κ-PVIIA is a small, structurally constrained, 27-residue peptide that inhibits voltage-gated K channels. Three disulfide bonds shape a characteristic four-loop folding. The spatial localization of positively charged residues in κ-PVIIA exhibits strong structural mimicry to that of charybdotoxin, a scorpion toxin that occludes the <span class="hlt">pore</span> of K channels. We studied the mechanism by which this peptide inhibits Shaker K channels expressed in Xenopus oocytes with the N-type inactivation removed. Chronically applied to whole oocytes or outside-out patches, κ-PVIIA inhibition appears as a voltage-dependent relaxation in response to the depolarizing pulse used to activate the channels. At any applied voltage, the relaxation rate depended linearly on the toxin concentration, indicating a bimolecular stoichiometry. Time constants and voltage dependence of the current relaxation produced by chronic applications agreed with that of rapid applications to open channels. Effective valence of the voltage dependence, zδ, is ∼0.55 and resides primarily in the rate of dissociation from the channel, while the association rate is voltage independent with a magnitude of 107–108 M−1 s−1, consistent with diffusion-limited binding. Compatible with a purely competitive interaction for a site in the external vestibule, tetraethylammonium, a well-known K-<span class="hlt">pore</span> blocker, reduced κ-PVIIA's association rate only. Removal of internal K+ reduced, but did not eliminate, the effective valence of the toxin dissociation rate to a value <0.3. This trans-<span class="hlt">pore</span> effect suggests that: (a) as in the α-KTx, a positively charged side chain, possibly a Lys, interacts electrostatically with ions residing inside the Shaker <span class="hlt">pore</span>, and (b) a part of the toxin occupies an externally accessible K+ binding site, decreasing the degree of <span class="hlt">pore</span> occupancy</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/123342','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/123342"><span>Chlorofluorocarbon-11 removal in anoxic <span class="hlt">marine</span> <span class="hlt">waters</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bullister, J.L.; Lee, B.S.</p> <p>1995-07-15</p> <p>Measurements of the chlorofluorocarbons CCl{sub 3}F (F-11) and CCl{sub 2}F{sub 2}(F-12) made in the subsurface anoxic zones of the Black Sea and Saanich Inlet, B.C., Canada show a pronounced depletion of dissolved F-11. These zones are strongly reducing and are characterized by the absence of dissolved nitrate (NO{sub 3}{sup {minus}}) and the presence of hydrogen sulfide (H{sub 2}S). Models incorporating the atmospheric input histories of these CFCs and the observed distributions are used to estimate residence times for <span class="hlt">water</span> in these zones and first order in-situ removal rates for F-11. In contrast, measurements in the mid-depth low-oxygen zone of the eastern Pacific (where NO{sub 3}{sup {minus}} is present and H{sub 2}S is below detection limits) do not show evidence of similar rapid F-11 removal. 22 refs., 3 figs., 1 tab.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6240107','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6240107"><span>Contaminated <span class="hlt">marine</span> sediments: <span class="hlt">Water</span> column and interstitial toxic effects</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Burgess, R.M.; Schweitzer, K.A.; McKinney, R.A.; Phelps, D.K.</p> <p>1993-01-01</p> <p>The toxicity that contaminated sediments may introduce into the <span class="hlt">water</span> column has not been measured extensively. In order to quantify this potential toxicity, the seawater overlying two uncontaminated and three contaminated <span class="hlt">marine</span> sediments was evaluated in the laboratory with the sea urchin Arbacia punctulata fertilization test. Concentrations of polychlorinated biphenyls (PCBs) and copper, as representative contaminants, were also measured. To characterize sources of toxicity, samples were chemically manipulated using reversed-phase chromatography, cation exchange, and chelation. <span class="hlt">Water</span> column toxicity and contaminant concentrations were higher in the suspended exposures than in bedded exposures. Interstitial <span class="hlt">water</span> toxicity and contaminant concentrations were generally greater than either bedded or suspended exposures. Chemical manipulation indicated that the observed toxicity in <span class="hlt">water</span> column exposures was probably caused by metallic and/or nonionic organic contaminants. Conversely, manipulation of interstitial <span class="hlt">waters</span> did not result in significantly reduced toxicity, suggesting that other toxicants such as ammonia and hydrogen sulfide may be active.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6449724','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6449724"><span>Contaminated <span class="hlt">marine</span> sediments: <span class="hlt">Water</span> column and interstitial toxic effects</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Burgess, R.M.; McKinney, R.A. ); Schweitzer, K.A. ); Phelps, D.K. )</p> <p>1993-01-01</p> <p>The toxicity that contaminated sediments may introduce into the <span class="hlt">water</span> column has not been measured extensively. In order to quantify this potential toxicity, the seawater overlying two uncontaminated and three contaminated <span class="hlt">marine</span> sediments was evaluated in the laboratory with the sea urchin Arbacia punctulata fertilization test. Concentration of polychlorinated biphenyls (PCBs) and copper, as representative contaminants, were also measured. To characterize sources of toxicity, samples were chemically manipulated using reversed-phase chromatography, cation exchange, and chelation. <span class="hlt">Water</span> column toxicity and contaminant concentrations were higher in the suspended exposures than in bedded exposures. Interstitial <span class="hlt">water</span> toxicity and contaminant concentrations were generally greater than either bedded or suspended exposures. Chemical manipulation indicated that the observed toxicity in <span class="hlt">water</span> column exposures was probably caused by metallic and/or nonionic organic contaminants. Conversely, manipulation of interstitial <span class="hlt">water</span> did not result in significantly reduced toxicity, suggesting that other toxicants such as ammonia and hydrogen sulfide may be active.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013GGG....14.1626B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GGG....14.1626B"><span>Using ammonium <span class="hlt">pore</span> <span class="hlt">water</span> profiles to assess stoichiometry of deep remineralization processes in methanogenic continental margin sediments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Burdige, David J.; Komada, Tomoko</p> <p>2013-05-01</p> <p>many continental margin sediments, a deep reaction zone exists which is separated from remineralization processes near the sediment surface. Here, methane diffuses upward to a depth where it is oxidized by downwardly diffusing sulfate. However, the methane sources that drive this anaerobic oxidation of methane (AOM) in the sulfate-methane transition zone (SMT) may vary among sites. In particular, these sources can be thought of as either (i) "internal" sources from in situ methanogenesis (regardless of where it occurs in the sediment column) that are ultimately coupled to organic matter deposition and burial, or (ii) "external" sources such as hydrocarbon reservoirs derived from ancient source rocks, or deeply buried gas hydrates, both of which are decoupled from contemporaneous organic carbon deposition at the sediment surface. Using a modeling approach, we examine the relationship between different methane sources and <span class="hlt">pore</span> <span class="hlt">water</span> sulfate, methane, dissolved inorganic carbon (DIC), and ammonium profiles. We show that <span class="hlt">pore</span> <span class="hlt">water</span> ammonium profiles through the SMT represent an independent "tracer" of remineralization processes occurring in deep sediments that complement information obtained from profiles of solutes directly associated with AOM and carbonate precipitation, i.e., DIC, methane, and sulfate. <span class="hlt">Pore</span> <span class="hlt">water</span> DIC profiles also show an inflection point in the SMT based on the type of deep methane source and the presence/absence of accompanying upward DIC fluxes. With these results, we present a conceptual framework which illustrates how shallow <span class="hlt">pore</span> <span class="hlt">water</span> profiles from continental margin settings can be used to obtain important information about remineralization processes and methane sources in deep sediments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JCHyd.142...75P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JCHyd.142...75P"><span>Influence of <span class="hlt">pore</span> <span class="hlt">water</span> velocity on the release of carbofuran and fenamiphos from commercial granulates embedded in a porous matrix</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Paradelo, Marcos; Pérez-Rodríguez, Paula; Arias-Estévez, Manuel; López-Periago, J. Eugenio</p> <p>2012-11-01</p> <p><span class="hlt">Pore</span> <span class="hlt">water</span> flow velocity can influence the processes involved in the contaminant transport between relative stagnant zones of porous media and their adjacent mobile zones. A particular case of special interest is the occurrence of high flow rates around the controlled release granules containing pesticides buried in soil. The release of the pesticides carbofuran and fenamiphos from commercial controlled release formulations (CRFs) was studied, comparing release tests in a finite volume of <span class="hlt">water</span> with <span class="hlt">water</span> flow release tests in saturated packed sand at different seepage velocities. For <span class="hlt">water</span> release kinetics, the time taken for 50% of the pesticide to be released (T50) was 0.64 hours for carbofuran and 1.97 hours for fenamiphos. In general, the release rate was lower in the porous matrix than in the free <span class="hlt">water</span> tests. The faster release rate for carbofuran was attributed to its higher <span class="hlt">water</span> diffusivity. The seepage velocity has a strong influence on the pesticide release rate. The dominant release mechanism varies with the progress of release. The evolution of the mechanism is discussed on the basis of the successive steps that involve the moving boundary of the dissolution front of the pesticide inside the granule, the concentration gradient inside the granule and the flow boundary layer resistance to solute diffusion around the granule. The <span class="hlt">pore</span> <span class="hlt">water</span> velocity influences the overall release dynamics. Therefore, seepage velocity should be considered in pesticide release to evaluate the risk of pesticide leaching, especially in scenarios with fast infiltration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/334212','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/334212"><span>Ion and <span class="hlt">water</span> transport in a Nafion{reg_sign} membrane <span class="hlt">pore</span>: A statistical mechanical model with molecular structure</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Paddison, S.J.; Zawodzinski, T.A. Jr.; Paul, R.</p> <p>1998-12-31</p> <p>With the well established importance of the coupling of <span class="hlt">water</span> and protons through electroosmotic drag in operating PEFCs the authors present here a derivation of a mathematical model that focuses on the computation of the mobility of an hydronium ion through an arbitrary cylindrical <span class="hlt">pore</span> of a PEM with a non-uniform charge distribution on the walls of the <span class="hlt">pore</span>. The total Hamiltonian is derived for the hydronium ion as it moves through the hydrated <span class="hlt">pore</span> and is effected by the net potential due to interaction with the solvent molecules and the pendant side chains. The corresponding probability density is derived through solution of the Liouville equation. This probability density is then used to compute the friction tensor for the hydronium ion. The authors find two types of contributions: (a) due to the solvent-ion interactions for which they adopt the conventional continuum model; (b) due to the interaction between the pendant charges and the hydronium ion. The latter is a new result and displays the role of the non-uniform nature of the charge distribution on the <span class="hlt">pore</span> wall.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70005222','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70005222"><span>Characterization of the intragranular <span class="hlt">water</span> regime within subsurface sediments: <span class="hlt">pore</span> volume, surface area, and mass transfer limitations</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hay, Michael B.; Stoliker, Deborah L.; Davis, James A.; Zachara, John M.</p> <p>2011-01-01</p> <p>Although "intragranular" <span class="hlt">pore</span> space within grain aggregates, grain fractures, and mineral surface coatings may contain a relatively small fraction of the total porosity within a porous medium, it often contains a significant fraction of the reactive surface area, and can thus strongly affect the transport of sorbing solutes. In this work, we demonstrate a batch experiment procedure using tritiated <span class="hlt">water</span> as a high-resolution diffusive tracer to characterize the intragranular <span class="hlt">pore</span> space. The method was tested using uranium-contaminated sediments from the vadose and capillary fringe zones beneath the former 300A process ponds at the Hanford site (Washington). Sediments were contacted with tracers in artificial groundwater, followed by a replacement of bulk solution with tracer-free groundwater and the monitoring of tracer release. From these data, intragranular <span class="hlt">pore</span> volumes were calculated and mass transfer rates were quantified using a multirate first-order mass transfer model. Tritium-hydrogen exchange on surface hydroxyls was accounted for by conducting additional tracer experiments on sediment that was vacuum dried after reaction. The complementary ("wet" and "dry") techniques allowed for the simultaneous determination of intragranular porosity and surface area using tritium. The Hanford 300A samples exhibited intragranular <span class="hlt">pore</span> volumes of ~1% of the solid volume and intragranular surface areas of ~20%–35% of the total surface area. Analogous experiments using bromide ion as a tracer yielded very different results, suggesting very little penetration of bromide into the intragranular porosity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70036215','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70036215"><span>Characterization of the intragranular <span class="hlt">water</span> regime within subsurface sediments: <span class="hlt">Pore</span> volume, surface area, and mass transfer limitations</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hay, M.B.; Stoliker, D.L.; Davis, J.A.; Zachara, J.M.</p> <p>2011-01-01</p> <p>Although "intragranular" <span class="hlt">pore</span> space within grain aggregates, grain fractures, and mineral surface coatings may contain a relatively small fraction of the total porosity within a porous medium, it often contains a significant fraction of the reactive surface area, and can thus strongly affect the transport of sorbing solutes. In this work, we demonstrate a batch experiment procedure using tritiated <span class="hlt">water</span> as a high-resolution diffusive tracer to characterize the intragranular <span class="hlt">pore</span> space. The method was tested using uranium-contaminated sediments from the vadose and capillary fringe zones beneath the former 300A process ponds at the Hanford site (Washington). Sediments were contacted with tracers in artificial groundwater, followed by a replacement of bulk solution with tracer-free groundwater and the monitoring of tracer release. From these data, intragranular <span class="hlt">pore</span> volumes were calculated and mass transfer rates were quantified using a multirate first-order mass transfer model. Tritium-hydrogen exchange on surface hydroxyls was accounted for by conducting additional tracer experiments on sediment that was vacuum dried after reaction. The complementary ("wet" and "dry") techniques allowed for the simultaneous determination of intragranular porosity and surface area using tritium. The Hanford 300A samples exhibited intragranular <span class="hlt">pore</span> volumes of ???1% of the solid volume and intragranular surface areas of ???20%-35% of the total surface area. Analogous experiments using bromide ion as a tracer yielded very different results, suggesting very little penetration of bromide into the intragranular porosity. Copyright 2011 by the American Geophysical Union.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/14672723','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/14672723"><span>Changes in constituent equilibrium leaching and <span class="hlt">pore</span> <span class="hlt">water</span> characteristics of a Portland cement mortar as a result of carbonation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Garrabrants, A C; Sanchez, F; Kosson, D S</p> <p>2004-01-01</p> <p>Two equilibrium-based characterization protocols were applied to ground samples of a cement-based material containing metal oxide powders in both noncarbonated and carbonated states. The effects of carbonation were shown through comparison of (i) material buffering capacity, (ii) constituent equilibrium as a function of leachate pH, and (iii) constituent solubility and release as a function of liquid-to-solid (LS) ratio. As expected, the material alkalinity was significantly neutralized during carbonation. In addition, carbonation of the cement material led to the formation of calcium carbonate and a corresponding increase in arsenic release across the entire pH range. The solubility as a function of pH for lead and copper was lower in the alkaline pH range (pH>9) for carbonated samples compared with the parent material. When solubility and release as a function of LS ratio was compared, carbonation was observed to decrease calcium solubility, sodium and potassium release, and ionic strength. In response to carbonate solid formation, chloride and sulfate release as a function of LS ratio was observed to increase. Trends in constituent concentration as a function of LS ratio were extrapolated to estimate <span class="hlt">pore</span> <span class="hlt">water</span> composition at a 0.06 mL/g LS ratio. Significant differences were observed upon comparison of estimated <span class="hlt">pore</span> <span class="hlt">water</span> composition to leachate concentrations extracted at LS ratio of 5 mL/g. These differences show that practical laboratory extractions cannot be assumed directly representative of <span class="hlt">pore</span> <span class="hlt">water</span> concentrations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21538492','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21538492"><span>Intercomparison and applicability of some dynamic and equilibrium approaches to determine methylated mercury species in <span class="hlt">pore</span> <span class="hlt">water</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Jinling; Feng, Xinbin; Qiu, Guangle; Yao, Heng; Shang, Lihai; Yan, Haiyu</p> <p>2011-08-01</p> <p>To assess adequately the impact of methylmercury (MeHg) on sensitive wetland ecosystems, accurate measurements of MeHg in <span class="hlt">pore</span> <span class="hlt">water</span> are required. In the present study, the feasibility of three methods for porewater sampling was investigated with respect to MeHg in sediments and rice paddy fields. The performance of dialysis samplers (peepers), sediment core sectioning followed by porewater separation by centrifugation (core), and the thin film diffusive samplers (DGT) were evaluated. These methods were intercompared in field experiments at two sites in Guizhou province, SW China disparately impacted by mercury pollution. All the methods report that the concentrations of MeHg in the soils of the Gouxi (GX) rice paddy near Wanshan were much higher than that in the sediment of the Hongjiadu Reservoir (HR), which is located within the Wujiang River basin. The three methods also report different MeHg profiles at the same site. However, these methods exhibit different temporal and spatial resolution scales, due to the differing operations involved with the sampling methods, may also reflect different states of MeHg in <span class="hlt">pore</span> <span class="hlt">water</span>. This corresponds to MeHg derived from diffusive flux, equilibrium concentration, and bulk concentration in <span class="hlt">pore</span> <span class="hlt">water</span> detected by DGT, peeper, and sediment core, respectively. The advantages and limits of the three methods are also presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/211908','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/211908"><span>Bioavailability of metals and toxicity identification of the sediment <span class="hlt">pore</span> <span class="hlt">waters</span> from Plow Shop Pond, Fort Devens, Massachusetts</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jop, K.; Putt, A.; Shepherd, S.; Askew, A.; Bleiler, J.; Reed, S.; George, C.</p> <p>1995-12-31</p> <p>Plow Shop Pond is a shallow, 30-acre pond located at Fort Devens, Massachusetts. An ecological risk assessment was conducted at Plow Shop Pond as part of a remedial investigation. Preliminary analysis revealed high concentrations of arsenic, copper, chromium, lead, and mercury in the sediment. Therefore, a laboratory testing program was incorporated into this investigation to assess the toxicity of sediments to aquatic organisms. The screening testing program included short-term chronic exposure of Ceriodaphnia dubia to <span class="hlt">pore</span> <span class="hlt">waters</span>, 10-day exposures of Chironomus tentans and Hyalella azteca to bulk sediments and a bioaccumulation study with Lumbriculus variegatus. Survival and reproduction of C. dubia, growth of amphipods and reproduction of oligochaetes appeared to indicate sediment toxicity at some sites within the pond. Although high concentrations of arsenic, copper, mercury and lead were detected in the whole sediments and <span class="hlt">pore</span> <span class="hlt">waters</span>, the response could not be correlated to a particular element. Also, relatively low bioaccumulation of methyl mercury and high uptake of inorganic mercury was established for three sediment samples. To characterize and identify the source of toxicity, a toxicity identification evaluation program using sediments collected at several locations was performed. The <span class="hlt">pore</span> <span class="hlt">water</span> from these samples was used for fractionation coupled with a 10-day test using H. azteca. Survival and growth were evaluated as endpoints during the exposures. Partitioning of metals and their bioavailability was influenced primarily by organic carbon and AVS concentration. At least two constituents were responsible for the toxicity.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.9784R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.9784R"><span>Evaluation of chloride mass balance of <span class="hlt">pore</span> <span class="hlt">water</span> as an indicator of groundwater recharge to the Monterrey Metropolitan Area, Mexico</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rosales-Lagarde, Laura; Pasten, Ernesto; Mora, Abrahan; Mahlknecht, Jürgen</p> <p>2016-04-01</p> <p>Monterrey Metropolitan Area in Nuevo Leon, Mexico, is the third largest metropolitan area and one of the most important industrial sites of Mexico. Groundwater constitutes 40% of the <span class="hlt">water</span> supply to this urban area. This supply is under constant stress due to the population increase. The unsaturated zone at six sites along two cross-sections was characterized to evaluate the potential of chloride concentration as an indicator of recharge. The selected sites include the range of topographic elevations, vegetation, and annual precipitation of the study area. In each site, boreholes up to 5 m deep were drilled and soil was sampled every 0.5 m. The grain size of each soil sample was determined and <span class="hlt">pore</span> <span class="hlt">water</span> extracted to determine the <span class="hlt">water</span> content percentage, and the chloride, sulfate and nitrate concentration of the <span class="hlt">pore</span> <span class="hlt">water</span>. The undersaturated zone consists of alluvial deposits with an average gravel and sand content greater than 60% for all but one of the sampling sites. The <span class="hlt">pore</span> <span class="hlt">water</span> content varies from 0.4 to 25% by weight with a decreasing trend as depth increases in areas with agriculture. Sulfate has the highest anion concentration in the <span class="hlt">pore</span> <span class="hlt">waters</span>, ranging from 42 to 45,000 mg/L and no apparent distribution pattern along the soil profile columns. Chloride concentration ranges from 8 to 3600 mg/L with an increase in concentration below 1.5 m depth in all the profiles. Chloride and sulfate concentrations with depth are directly correlated suggesting a common input, possibly dissolution-precipitation of evaporite minerals from nearby outcrops or an anthropogenic input. Hence, it is unlikely that chloride behaves as a conservative ion. As a result, its concentration is not likely to be a good indicator of groundwater recharge. Finally; the nitrate concentration ranges from 2 to 96 mg/L nitrate, without a clear pattern along the soil profiles. Low concentration of nitrate in the soil profiles below agricultural areas may suggest denitrification as suggested</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/658778','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/658778"><span>Canadian <span class="hlt">water</span> quality guidelines. Appendix 22: Interim <span class="hlt">marine</span> and estuarine <span class="hlt">water</span> quality guidelines for general variables</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p></p> <p>1996-12-31</p> <p>This document has been prepared in response to the need for <span class="hlt">marine</span> <span class="hlt">water</span> quality guidelines for general <span class="hlt">water</span> quality variables. It presents interim guidelines, summaries of existing guidelines if any, the rationale for the guidelines, and variable-specific background information, and notes gaps in data, for the following variables: Debris, including floating or submerged litter, and settleable matter; dissolved oxygen; pH; salinity; temperature; and suspended solids and turbidity. For the purpose of this document, the <span class="hlt">marine</span> environment includes shorelines, estuaries up to the freshwater limit, and nearshore and offshore <span class="hlt">waters</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70017363','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70017363"><span>Differential equations governing slip-induced <span class="hlt">pore</span>-pressure fluctuations in a <span class="hlt">water</span>-saturated granular medium</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Iverson, R.M.</p> <p>1993-01-01</p> <p>Macroscopic frictional slip in <span class="hlt">water</span>-saturated granular media occurs commonly during landsliding, surface faulting, and intense bedload transport. A mathematical model of dynamic <span class="hlt">pore</span>-pressure fluctuations that accompany and influence such sliding is derived here by both inductive and deductive methods. The inductive derivation shows how the governing differential equations represent the physics of the steadily sliding array of cylindrical fiberglass rods investigated experimentally by Iverson and LaHusen (1989). The deductive derivation shows how the same equations result from a novel application of Biot's (1956) dynamic mixture theory to macroscopic deformation. The model consists of two linear differential equations and five initial and boundary conditions that govern solid displacements and <span class="hlt">pore-water</span> pressures. Solid displacements and <span class="hlt">water</span> pressures are strongly coupled, in part through a boundary condition that ensures mass conservation during irreversible <span class="hlt">pore</span> deformation that occurs along the bumpy slip surface. Feedback between this deformation and the <span class="hlt">pore</span>-pressure field may yield complex system responses. The dual derivations of the model help explicate key assumptions. For example, the model requires that the dimensionless parameter B, defined here through normalization of Biot's equations, is much larger than one. This indicates that solid-fluid coupling forces are dominated by viscous rather than inertial effects. A tabulation of physical and kinematic variables for the rod-array experiments of Iverson and LaHusen and for various geologic phenomena shows that the model assumptions commonly are satisfied. A subsequent paper will describe model tests against experimental data. ?? 1993 International Association for Mathematical Geology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26829659','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26829659"><span>Colloid Mobilization in a Fractured Soil: Effect of <span class="hlt">Pore-Water</span> Exchange between Preferential Flow Paths and Soil Matrix.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mohanty, Sanjay K; Saiers, James E; Ryan, Joseph N</p> <p>2016-03-01</p> <p>Exchange of <span class="hlt">water</span> and solutes between contaminated soil matrix and bulk solution in preferential flow paths has been shown to contribute to the long-term release of dissolved contaminants in the subsurface, but whether and how this exchange can affect the release of colloids in a soil are unclear. To examine this, we applied rainfall solutions of different ionic strength on an intact soil core and compared the resulting changes in effluent colloid concentration through multiple sampling ports. The exchange of <span class="hlt">water</span> between soil matrix and the preferential flow paths leading to each port was characterized on the basis of the bromide (conservative tracer) breakthrough time at the port. At individual ports, two rainfalls of a certain ionic strength mobilized different amounts of colloids when the soil was pre-exposed to a solution of lower or higher ionic strength. This result indicates that colloid mobilization depended on rainfall solution history, which is referred as colloid mobilization hysteresis. The extent of hysteresis was increased with increases in exchange of <span class="hlt">pore</span> <span class="hlt">water</span> and solutes between preferential flow paths and matrix. The results indicate that the soil matrix exchanged the old <span class="hlt">water</span> from the previous infiltration with new infiltrating <span class="hlt">water</span> during successive infiltration and changed the <span class="hlt">pore</span> <span class="hlt">water</span> chemistry in the preferential flow paths, which in turn affected the release of soil colloids. Therefore, rainfall solution history and soil heterogeneity must be considered to assess colloid mobilization in the subsurface. These findings have implications for the release of colloids, colloid-associated contaminants, and pathogens from soils.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.1172T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.1172T"><span>Gas Hydrate and <span class="hlt">Pore</span> Pressure</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tinivella, Umberta; Giustiniani, Michela</p> <p>2014-05-01</p> <p>Many efforts have been devoted to quantify excess <span class="hlt">pore</span> pressures related to gas hydrate dissociation in <span class="hlt">marine</span> sediments below the BSR using several approaches. Dissociation of gas hydrates in proximity of the BSR, in response to a change in the physical environment (i.e., temperature and/or pressure regime), can liberate excess gas incrising the local <span class="hlt">pore</span> fluid pressure in the sediment, so decreasing the effective normal stress. So, gas hydrate dissociation may lead to excess <span class="hlt">pore</span> pressure resulting in sediment deformation or failure, such as submarine landslides, sediment slumping, pockmarks and mud volcanoes, soft-sediment deformation and giant hummocks. Moreover, excess <span class="hlt">pore</span> pressure may be the result of gas hydrate dissociation due to continuous sedimentation, tectonic uplift, sea level fall, heating or inhibitor injection. In order to detect the presence of the overpressure below the BSR, we propose two approachs. The fist approach models the BSR depth versus <span class="hlt">pore</span> pressure; in fact, if the free gas below the BSR is in overpressure condition, the base of the gas hydrate stability is deeper with respect to the hydrostatic case. This effect causes a discrepancy between seismic and theoretical BSR depths. The second approach models the velocities versus gas hydrate and free gas concentrations and <span class="hlt">pore</span> pressure, considering the approximation of the Biot theory in case of low frequency, i.e. seismic frequency. Knowing the P and S seismic velocity from seismic data analysis, it is possibile to jointly estimate the gas hydrate and free gas concentrations and the <span class="hlt">pore</span> pressure regime. Alternatively, if the S-wave velocity is not availbale (due to lack of OBS/OBC data), an AVO analysis can be performed in order to extract information about Poisson ratio. Our modeling suggests that the areas characterized by shallow <span class="hlt">waters</span> (i.e., areas in which human infrastructures, such as pipelines, are present) are significantly affected by the presence of overpressure condition</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMNH41C1830H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMNH41C1830H"><span>Seasonal Effects on the Relationships Between Soil <span class="hlt">Water</span> Content, <span class="hlt">Pore</span> <span class="hlt">Water</span> Pressure and Shear Strength and Their Implications for Slope Stability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hughes, P. N.</p> <p>2015-12-01</p> <p>A soil's shear resistance is mainly dependent upon the magnitude of effective stress. For small to medium height slopes (up to 10m) in clay soils the total stress acting along potential failure planes will be low, therefore the magnitude of effective stress (and hence soil shear strength) will be dominated by the <span class="hlt">pore-water</span> pressure. The stability of slopes on this scale through periods of increased precipitation is improved by the generation of negative <span class="hlt">pore</span> pressures (soil suctions) during preceding, warmer, drier periods. These negative <span class="hlt">pore</span> <span class="hlt">water</span> pressures increase the effective stress within the soil and cause a corresponding increase in shearing resistance. The relationships between soil <span class="hlt">water</span> content and <span class="hlt">pore</span> <span class="hlt">water</span> pressure (soil <span class="hlt">water</span> retention curves) are known to be hysteretic, but for the purposes of the majority of slope stability assessments in partially saturated clay soils, these are assumed to be consistent with time. Similarly, the relationship between shear strength and <span class="hlt">water</span> content is assumed to be consistent over time. This research presents a laboratory study in which specimens of compacted Glacial Till (typical of engineered slopes within the UK) were subjected to repeated cycles of wetting and drying to simulate seasonal cycles. At predetermined <span class="hlt">water</span> contents, measurements of soil suction were made using tensiometer and dewpoint potentiometer methods. The undrained shear strength of the specimens was then measured using triaxial strength testing equipment. Results indicate that repeated wetting and drying cycles caused a change in the soil <span class="hlt">water</span> retention behaviour. A reduction in undrained shear strength at corresponding <span class="hlt">water</span> contents along the wetting and drying paths was also observed. The mechanism for the change in the relationship is believed to be a deterioration in the soil physical structure due to shrink/swell induced micro-cracking. The non-stationarity of these relationships has implications for slope stability assessment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27049790','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27049790"><span>Use of sunlight to degrade oxytetracycline in <span class="hlt">marine</span> aquaculture's <span class="hlt">waters</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Leal, J F; Esteves, V I; Santos, E B H</p> <p>2016-06-01</p> <p>Oxytracycline (OTC) is a broad spectrum antibiotic authorized for use in European aquaculture. Its photo-degradation has been widely studied in synthetic aqueous solutions, sometimes resorting to expensive methods and without proven effectiveness in natural <span class="hlt">waters</span>. Thus, this work studied the possibility to apply the solar photo-degradation for removal of OTC from <span class="hlt">marine</span> aquaculture's <span class="hlt">waters</span>. For that, <span class="hlt">water</span> samples were collected at different locals of the <span class="hlt">water</span> treatment circuit, from two different aquaculture companies. <span class="hlt">Water</span> samples were firstly characterized regarding to pH, salinity, total suspended solids (TSS), organic carbon and UV-Vis spectroscopic characteristics. Then, the samples were spiked with OTC and irradiated using simulated sunlight in order to evaluate the matrix effects on OTC photo-degradation. From kinetic results, the apparent quantum yields and the outdoor half-life times, at 40°N for midsummer and midwinter days were estimated by the first time for these conditions. For a midsummer day, at sea level, the outdoor half-life time predicted for OTC in these aquaculture's <span class="hlt">waters</span> ranged between 21 and 25 min. Additionally, the pH and salinity effects on the OTC photo-degradation were evaluated and it has been shown that high pH values and the presence of sea salt increase the OTC photo-degradation rate in aquaculture's <span class="hlt">waters</span>, compared to results in deionised <span class="hlt">water</span>. The results are very promising to apply this low-cost methodology using the natural sunlight in aquaculture's <span class="hlt">waters</span> to remove OTC.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27974156','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27974156"><span>Floating <span class="hlt">Marine</span> Debris in <span class="hlt">waters</span> of the Mexican Central Pacific.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Díaz-Torres, Evelyn R; Ortega-Ortiz, Christian D; Silva-Iñiguez, Lidia; Nene-Preciado, Alejandro; Orozco, Ernesto Torres</p> <p>2017-02-15</p> <p>The presence of <span class="hlt">marine</span> debris has been reported recently in several oceans basins; there is very little information available for Mexican Pacific coasts, however. This research examined the composition, possible sources, distribution, and density of Floating <span class="hlt">Marine</span> Debris (FMD) during nine research surveys conducted during 2010-2012 in the Mexican Central Pacific (MCP). Of 1820 floating objects recorded, 80% were plastic items. Sources of FMD were determined using key objects, which indicated that the most were related to the presence of the industrial harbor and of a growing fishing industry in the study area. Densities were relatively high, ranging from 40 to 2440objects/km(2); the highest densities were recorded in autumn. FMD were distributed near coastal regions, mainly in Jalisco, influenced by river outflow and surface currents. Our results seem to follow worldwide trends and highlight the need for further studies on potential ecological impacts within coastal <span class="hlt">waters</span> of the MCP.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/949046','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/949046"><span>A <span class="hlt">pore</span>-scale model of two-phase flow in <span class="hlt">water</span>-wet rock</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Silin, Dmitriy; Patzek, Tad</p> <p>2009-02-01</p> <p>A finite-difference discretization of Stokes equations is used to simulate flow in the <span class="hlt">pore</span> space of natural rocks. Numerical solutions are obtained using the method of artificial compressibility. In conjunction with Maximal Inscribed Spheres method, these computations produce relative permeability curves. The results of computations are in agreement with laboratory measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70025689','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70025689"><span>Chemical analyses of <span class="hlt">pore</span> <span class="hlt">water</span> from boreholes USW SD-6 and USW WT-24, Yucca Mountain, Nevada</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Yang, I.C.; Peterman, Z.E.; Scofield, K.M.</p> <p>2003-01-01</p> <p>Analyses of <span class="hlt">pore</span> <span class="hlt">water</span> extracted from cores of boreholes USW SD-6 in the central part and USW WT-24 in the northern part of Yucca Mountain, Nevada, show significant vertical and lateral variations in dissolved-ion concentrations. Analyses of samples of only a few milliliters of <span class="hlt">pore</span> <span class="hlt">water</span> extracted by uniaxial or triaxial compression and by ultracentrifugation methods from adjacent core samples are generally in agreement, within the analytical error of 10% to 15%. However, the values of silica for <span class="hlt">water</span> obtained by ultracentrifugation are consistently lower than values for <span class="hlt">water</span> obtained by compression. The larger concentrations probably are due to localized pressure solution of silicate minerals during compression. The shallower <span class="hlt">water</span> from core in borehole USW SD-6 was extracted from nonwelded units collectively referred to as the Paintbrush Tuff nonwelded (PTn). The deeper <span class="hlt">water</span> was from core in both boreholes USW SD-6 and USW WT-24 in the nonwelded units referred to as the Calico Hills nonwelded (CHn). Significant differences in mean dissolved-ion concentrations in <span class="hlt">pore</span> <span class="hlt">water</span> between the PTn and CHn are (1) decreases in Ca, Mg, SO4, and NO3 and (2) increases in HCO3 and (Na+K)/(Ca+Mg) ratios. The decrease in NO3 and the increase in HCO3 could be the result of denitrification through the oxidation of organic matter. The decrease in Ca and associated increase in (Na+K)/(Ca+Mg) is the result of ion exchange with zeolites in the CHn in borehole USW WT-24. This effect is not nearly as pronounced in borehole USW SD-6, probably reflecting a smaller amount of zeolitization of the CHn in USW SD-6. Geochemical calculations using the PHREEQC code indicate that the <span class="hlt">pore</span> <span class="hlt">water</span> from both boreholes USW SD-6 and USW WT-24 is uniformly undersaturated in anhydrite, gypsum, and amorphous silica, but supersaturated in quartz and chalcedony. The saturation of calcite, aragonite, sepiolite, and dolomite is more variable from sample to sample. ?? 2002 Elsevier Science B.V. All rights</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/837485','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/837485"><span>Strontium Isotopes in <span class="hlt">Pore</span> <span class="hlt">Water</span> as an Indicator of <span class="hlt">Water</span> Flux at the Proposed High-Level Radioactive Waste Repository, Yucca Mountain, Nevada</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>B. Marshall; K. Futa</p> <p>2004-02-19</p> <p>The proposed high-level radioactive waste repository at Yucca Mountain, Nevada, would be constructed in the high-silica rhyolite (Tptp) member of the Miocene-age Topopah Spring Tuff, a mostly welded ash-flow tuff in the {approx}500-m-thick unsaturated zone. Strontium isotope compositions have been measured in <span class="hlt">pore</span> <span class="hlt">water</span> centrifuged from preserved core samples and in leachates of <span class="hlt">pore-water</span> salts from dried core samples, both from boreholes in the Tptp. Strontium isotope ratios ({sup 87}Sr/{sup 86}Sr) vary systematically with depth in the surface-based boreholes. Ratios in <span class="hlt">pore</span> <span class="hlt">water</span> near the surface (0.7114 to 0.7124) reflect the range of ratios in soil carbonate (0.7112 to 0.7125) collected near the boreholes, but ratios in the Tptp (0.7122 to 0.7127) at depths of 150 to 370 m have a narrower range and are more radiogenic due to interaction with the volcanic rocks (primarily non-welded tuffs) above the Tptp. An advection-reaction model relates the rate of strontium dissolution from the rocks with flow velocity. The model results agree with the low transport velocity ({approx}2 cm per year) calculated from carbon-14 data by I.C. Yang (2002, App. Geochem., v. 17, no. 6, p. 807-817). Strontium isotope ratios in <span class="hlt">pore</span> <span class="hlt">water</span> from Tptp samples from horizontal boreholes collared in tunnels at the proposed repository horizon have a similar range (0.7121 to 0.7127), also indicating a low transport velocity. Strontium isotope compositions of <span class="hlt">pore</span> <span class="hlt">water</span> below the proposed repository in core samples from boreholes drilled vertically downward from tunnel floors are more varied, ranging from 0.7112 to 0.7127. The lower ratios (<0.7121) indicate that some of the <span class="hlt">pore</span> <span class="hlt">water</span> in these boreholes was replaced by tunnel construction <span class="hlt">water</span>, which had an {sup 87}Sr/{sup 86}Sr of 0.7115. Ratios lower than 0.7115 likely reflect interaction of construction <span class="hlt">water</span> with concrete in the tunnel inverts, which had an {sup 87}Sr/{sup 86}Sr < 0.709. These low Sr ratios indicate penetration of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24704964','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24704964"><span>Response of <span class="hlt">pore</span> <span class="hlt">water</span> Al, Fe and S concentrations to waterlogging in a boreal acid sulphate soil.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Virtanen, Seija; Simojoki, Asko; Hartikainen, Helinä; Yli-Halla, Markku</p> <p>2014-07-01</p> <p>Environmental hazards caused by acid sulphate (AS) soils are of worldwide concern. Among various mitigation measures, waterlogging has mainly been studied in subtropical and tropical conditions. To assess the environmental relevance of waterlogging as a mitigation option in boreal AS soils, we arranged a 2.5-year experiment with monolithic lysimeters to monitor changes in the soil redox potential, pH and the concentrations of aluminium (Al), iron (Fe) and sulphur (S) in <span class="hlt">pore</span> <span class="hlt">water</span> in response to low and high groundwater levels in four AS soil horizons. The monoliths consisted of acidic oxidized B horizons and a reduced C horizon containing sulphidic material. Eight lysimeters were cropped (reed canary grass, Phalaris arundinacea) and two were bare without a crop. Waterlogging was conducive to reduction reactions causing a slight rise in pH, a substantial increase in Fe (Fepw) and a decrease in Al (Alpw) in the <span class="hlt">pore</span> <span class="hlt">water</span>. The increase in Fepw was decisively higher in the cropped waterlogged lysimeters than in the bare ones, which was attributable to the microbiologically catalysed reductive dissolution of poorly ordered iron oxides and secondary minerals. In contrast to warmer climates, Fepw concentrations remained high throughout the experiment, indicating that the reduction was poised in the iron range, while sulphate was not reduced to sulphide. Therefore, the precipitation of iron sulphide was negligible in the environment with a low pH and abundant with poorly ordered Fe oxides. Increased Fe in <span class="hlt">pore</span> <span class="hlt">water</span> counteracts the positive effects of waterlogging, when <span class="hlt">water</span> is flushed from fields to watercourses, where re-oxidation of Fe causes acidity and oxygen depletion. However, waterlogging prevented further oxidation of sulphidic materials and decreased Alpw to one-tenth of the initial concentrations, and even to one-hundredth of the levels in the low <span class="hlt">water</span> table lysimeters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12171411','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12171411"><span>A new rechargeable dialysis <span class="hlt">pore</span> <span class="hlt">water</span> sampler for monitoring sub-aqueous in-situ sediment caps.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jacobs, Patrick H</p> <p>2002-07-01</p> <p>A new rechargeable dialysis <span class="hlt">pore</span> <span class="hlt">water</span> sampler is proposed that is adapted to the requirements of monitoring in-situ sediment remediation techniques, in particular in-situ capping. Sampling and recharging of the sampler can be carried out from a boat or a pontoon by means of separate tubing and a peristaltic pump. The possibility of repeated sampling permits a temporal as well as a spatial resolution of <span class="hlt">pore</span> <span class="hlt">water</span> geochemistry. This aims to facilitate a monitoring of temporal variations in contaminant profiles within a cap matrix. To meet these particular requirements the basic peeper design is modified. In this manuscript constructive details and materials used are discussed as well as the feasibility and reliability of the sampling and recharging process. The peeper is designed for I m depth profile with spatial resolution of 1/5.5cm and the practical temporal resolution, that chiefly depends on sediment characteristics, is 1/3 weeks. Results from laboratory and field testing show that sample volumes of 20 cm3 can be obtained from a depth of 8 m without mixing of sample and recharge <span class="hlt">water</span>. The field test results with an exposure time of 8 months indicate that no clogging of neither the membranes nor the sample tubing occurred. The temporal development of the concentration-vs. -depth profiles of sodium, iron, and nickle, chosen as examples from the investigated metals in the <span class="hlt">pore</span> <span class="hlt">water</span>, document the stability of the monitoring system. The results thus corroborate that this new type of sampler can be employed as a tool for monitoring contaminants at the sediment-to-<span class="hlt">water</span> interface and particularly within an in-situ cap.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70042340','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70042340"><span><span class="hlt">Pore-water</span> chemistry from the ICDP-USGS coer hole in the Chesapeake Bay impact structure--Implications for paleohydrology, microbial habitat, and <span class="hlt">water</span> resources</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sanford, Ward E.; Voytek, Mary A.; Powars, David S.; Jones, Blair F.; Cozzarelli, Isabelle M.; Eganhouse, Robert P.; Cockell, Charles S.</p> <p>2009-01-01</p> <p>We investigated the groundwater system of the Chesapeake Bay impact structure by analyzing the <span class="hlt">pore-water</span> chemistry in cores taken from a 1766-m-deep drill hole 10 km north of Cape Charles, Virginia. <span class="hlt">Pore</span> <span class="hlt">water</span> was extracted using high-speed centrifuges from over 100 cores sampled from a 1300 m section of the drill hole. The <span class="hlt">pore-water</span> samples were analyzed for major cations and anions, stable isotopes of <span class="hlt">water</span> and sulfate, dissolved and total carbon, and bioavailable iron. The results reveal a broad transition between fresh and saline <span class="hlt">water</span> from 100 to 500 m depth in the post-impact sediment section, and an underlying syn-impact section that is almost entirely filled with brine. The presence of brine in the lowermost post-impact section and the trend in the dissolved chloride with depth suggest a transport process dominated by molecular diffusion and slow, compaction-driven, upward flow. Major ion results indicate residual effects of diagenesis from heating, and a pre-impact origin for the brine. High levels of dissolved organic carbon (6-95 mg/L) and the distribution of electron acceptors indicate an environment that may be favorable for microbial activity throughout the drilled section. The concentration and extent of the brine is much greater than had previously been observed, suggesting its occurrence may be common in the inner crater. However, groundwater flow conditions in the structure may reduce the salt-<span class="hlt">water</span>-intrusion hazard associated with the brine.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/962849','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/962849"><span>Electrical Resistivity Correlation to Vadose Zone Sediment and <span class="hlt">Pore-Water</span> Composition for the BC Cribs and Trenches Area</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Serne, R. Jeffrey; Ward, Anderson L.; Um, Wooyong; Bjornstad, Bruce N.; Rucker, Dale F.; Lanigan, David C.; Benecke, Mark W.</p> <p>2009-06-01</p> <p>This technical report documents the results of geochemical and soil resistivity characterization of sediment obtained from four boreholes drilled in the BC Cribs and Trench area. Vadose zone sediment samples were obtained at a frequency of about every 2.5 ft from approximately 5 ft bgs to borehole total depth. In total, 505 grab samples and 39 six-inch long cores were obtained for characterization. The <span class="hlt">pore-water</span> chemical composition data, laboratory-scale soil resistivity and other ancillary physical and hydrologic measurements and analyses described in this report are designed to provide a crucial link between direct measurements on sediments and the surface-based electrical-resistivity information obtained via field surveys. A second goal of the sediment characterization was to measure the total and <span class="hlt">water</span>-leachable concentrations of key contaminants of concern as a function of depth and distance from the footprints of inactive disposal facilities. The total and <span class="hlt">water</span>-leachable concentrations of key contaminants will be used to update contaminant distribution conceptual models and to provide more data for improving base-line risk predictions and remedial alternative selections. The ERC “ground truthing” exercise for the individual boreholes showed mixed results. In general, the high concentrations of dissolved salts in the <span class="hlt">pore</span> <span class="hlt">waters</span> of sediments from C5923, C5924 and C4191 produced a low resistivity “target” in the processed resistivity field surveys, and variability could be seen in the resistivity data that could relate to the variability in <span class="hlt">pore</span>- <span class="hlt">water</span> concentrations but the correlations (regression R2 were mediocre ranging from 0.2 to 0.7 at best; where perfect correlation is 1.0). The field-based geophysical data also seemed to suffer from a sort of vertigo, where looking down from the ground surface, the target (e.g., maximum <span class="hlt">pore-water</span> salt concentration) depth was difficult to resolve. The best correlations between the field electrical</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.B11D0378G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.B11D0378G"><span><span class="hlt">Pore</span> <span class="hlt">water</span> chemistry in a disturbed and an undisturbed peat forests in Brunei Darussalam: Nutrient and carbon contents</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gandois, L.; Cobb, A.; Abu Salim, K.; Chieng Hei, I.; Lim Biaw Leng, L.; Corlett, R.; Harvey, C.</p> <p>2010-12-01</p> <p>Tropical peat swamp forests in their natural state are important reservoir of biodiversity, carbon and <span class="hlt">water</span>. However, they are rapidly vanishing due to agricultural conversion (mainly to oil palms), logging, drainage and fire. Peat swamp forests constitute an important contribution to global and regional biodiversity, providing an habitat to rare and threatened species. They encompass a sequence of forest types from the perimeter to the center of mildely elevated domes, and at our site in Brunei, are host to Shorea Albida trees (Anderson, 1983). They constitute a large terrestrial carbon reservoir (tropical peat soils contain up to 70 Pg C, which accounts for 20% of global peat soil carbon and 2% of the global soil carbon (Hirano et al., 2007)). In tropical peat swamp forests, the most important factors controling organic matter accumulation, as well as the biodiversity and structure of the forest, are hydrology and nutrients availability (Page et al., 1999). Study of <span class="hlt">pore</span> <span class="hlt">water</span> in peat swamp forest can provide key information on carbon cycle, including biomass production, organic matter decomposition and leaching of carbon in draining <span class="hlt">water</span>. However, data on <span class="hlt">pore</span> <span class="hlt">water</span> chemistry and nutrient concentrations in pristine tropical peatlands, as well as the effect of forest exploitation are scarce. The study area is located in the Belait district in Brunei Darussalam in Borneo Island. Brunei is perhaps the best of the regional guardians of peat forest systems; potentially irreversible damage to peat forest ecosystems has been widespread elsewhere. Two sites, one pristine dome and a logging concession, are being investigated. In order to assess the chemical status of the peat soil, <span class="hlt">pore</span> <span class="hlt">water</span> is sampled at different depth along the dome radius. The chemistry of <span class="hlt">pore</span> <span class="hlt">water</span>, including pH, conductivity, dissolved oxygen, concentration of major elements, as well as organic carbon content and properties are analyzed. References: Anderson, 1983. The tropical peat swamp of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27389452','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27389452"><span>Prevalence of microplastics in the <span class="hlt">marine</span> <span class="hlt">waters</span> of Qatar.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Castillo, Azenith B; Al-Maslamani, Ibrahim; Obbard, Jeffrey Philip</p> <p>2016-10-15</p> <p>Microplastics are firmly recognized as a ubiquitous and growing threat to <span class="hlt">marine</span> biota and their associated <span class="hlt">marine</span> habitats worldwide. The evidence of the prevalence of microplastics was documented for the first time in the <span class="hlt">marine</span> <span class="hlt">waters</span> of Qatar's Exclusive Economic Zone (EEZ). An optimized and validated protocol was developed for the extraction of microplastics from plankton-rich seawater samples without loss of microplastic debris present and characterized using Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy. In total 30 microplastic polymers have been identified with an average concentration of 0.71particlesm(-3) (range 0-3particlesm(-3)). Polypropylene, low density polyethylene, polyethylene, polystyrene, polyamide, polymethyl methacrylate, cellophane, and acrylonitrile butadiene styrene polymers were characterized with majority of the microplastics either granular shape, sizes ranging from 125μm to 1.82mm or fibrous with sizes from 150μm to 15.98mm. The microplastics are evident in areas where nearby anthropogenic activities, including oil-rig installations and shipping operations are present.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.water.usgs.gov/sir2005-5036/','USGSPUBS'); return false;" href="http://pubs.water.usgs.gov/sir2005-5036/"><span>Pushpoint sampling for defining spatial and temporal variations in contaminant concentrations in sediment <span class="hlt">pore</span> <span class="hlt">water</span> near the ground-<span class="hlt">water</span> / surface-<span class="hlt">water</span> interface</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Zimmerman, Marc J.; Massey, Andrew J.; Campo, Kimberly W.</p> <p>2005-01-01</p> <p>During four periods from April 2002 to June 2003, <span class="hlt">pore-water</span> samples were taken from river sediment within a gaining reach (Mill Pond) of the Sudbury River in Ashland, Massachusetts, with a temporary pushpoint sampler to determine whether this device is an effective tool for measuring small-scale spatial variations in concentrations of volatile organic compounds and selected field parameters (specific conductance and dissolved oxygen concentration). The <span class="hlt">pore</span> <span class="hlt">waters</span> sampled were within a subsurface plume of volatile organic compounds extending from the nearby Nyanza Chemical Waste Dump Superfund site to the river. Samples were collected from depths of 10, 30, and 60 centimeters below the sediment surface along two 10-meter-long, parallel transects extending into the river. Twenty-five volatile organic compounds were detected at concentrations ranging from less than 1 microgram per liter to hundreds of micrograms per liter (for example, 1,2-dichlorobenzene, 490 micrograms per liter; cis-1,2-dichloroethene, 290 micrograms per liter). The most frequently detected compounds were either chlorobenzenes or chlorinated ethenes. Many of the compounds were detected only infrequently. Quality-control sampling indicated a low incidence of trace concentrations of contaminants. Additional samples collected with passive-<span class="hlt">water</span>-diffusion-bag samplers yielded results comparable to those collected with the pushpoint sampler and to samples collected in previous studies at the site. The results demonstrate that the pushpoint sampler can yield distinct samples from sites in close proximity; in this case, sampling sites were 1 meter apart horizontally and 20 or 30 centimeters apart vertically. Moreover, the pushpoint sampler was able to draw <span class="hlt">pore</span> <span class="hlt">water</span> when inserted to depths as shallow as 10 centimeters below the sediment surface without entraining surface <span class="hlt">water</span>. The simplicity of collecting numerous samples in a short time period (routinely, 20 to 30 per day) validates the use of a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6654414','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6654414"><span>Sulfide variation in the <span class="hlt">pore</span> and surface <span class="hlt">waters</span> of artificial salt-marsh ditches and a natural tidal creek</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rey, J.R.; Shaffer, J.; Kain, T.; Stahl, R.; Crossman, R. )</p> <p>1992-09-01</p> <p><span class="hlt">Pore</span> and surface <span class="hlt">water</span> sulfide variation near artificial ditches and a natural creek are examined in salt marshes bordering the Indian River Lagoon in east-central Florida. <span class="hlt">Pore</span> <span class="hlt">water</span> sulfide concentrations ranged from 0 [mu]g-at l[sup [minus]1] to 1,640 [mu]g-at l[sup [minus]1]. On average, the natural creek had the lowest sulfide concentrations (mean < 1.0 [mu]g-at l[sup [minus]1]) and the perimeter ditch of a managed salt marsh impoundment the highest (436.5 [mu]g-at l[sup [minus]1]). There was a trend of increasing sulfide concentration in the summer, and sharp peaks in late fall-early winter which correspond with peak litter input into the sediments. Significant differences in sulfide concentration between sites are attributed to differences in <span class="hlt">water</span> flow and in organic matter content. Delaying the seasonal opening of culverts (which connect impounded marshes with the lagoon) until lagoon <span class="hlt">water</span> levels rise in fall may prevent massive fish kills that have been associated with high sulfide levels in the impoundment perimeter ditches. 35 refs., 7 figs., 5 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/14641903','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/14641903"><span>Distribution of arsenic and copper in sediment <span class="hlt">pore</span> <span class="hlt">water</span>: an ecological risk assessment case study for offshore drilling waste discharges.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sadiq, Rehan; Husain, Tahir; Veitch, Brian; Bose, Neil</p> <p>2003-12-01</p> <p>Due to the hydrophobic nature of synthetic based fluids (SBFs), drilling cuttings are not very dispersive in the <span class="hlt">water</span> column and settle down close to the disposal site. Arsenic and copper are two important toxic heavy metals, among others, found in the drilling waste. In this article, the concentrations of heavy metals are determined using a steady state "aquivalence-based" fate model in a probabilistic mode. Monte Carlo simulations are employed to determine <span class="hlt">pore</span> <span class="hlt">water</span> concentrations. A hypothetical case study is used to determine the <span class="hlt">water</span> quality impacts for two discharge options: 4% and 10% attached SBFs, which correspond to the best available technology option and the current discharge practice in the U.S. offshore. The exposure concentration (CE) is a predicted environmental concentration, which is adjusted for exposure probability and bioavailable fraction of heavy metals. The response of the ecosystem (RE) is defined by developing an empirical distribution function of predicted no-effect concentration. The pollutants' <span class="hlt">pore</span> <span class="hlt">water</span> concentrations within the radius of 750 m are estimated and cumulative distributions of risk quotient (RQ=CE/RE) are developed to determine the probability of RQ greater than 1.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70033840','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70033840"><span><span class="hlt">Pore-water</span> chemistry from the ICDP-USGS core hole in the Chesapeake Bay impact structure-Implications for paleohydrology, microbial habitat, and <span class="hlt">water</span> resources</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sanford, W.E.; Voytek, M.A.; Powars, D.S.; Jones, B.F.; Cozzarelli, I.M.; Cockell, C.S.; Eganhouse, R.P.</p> <p>2009-01-01</p> <p>We investigated the groundwater system of the Chesapeake Bay impact structure by analyzing the <span class="hlt">pore-water</span> chemistry in cores taken from a 1766-m-deep drill hole 10 km north of Cape Charles, Virginia. <span class="hlt">Pore</span> <span class="hlt">water</span> was extracted using high-speed centrifuges from over 100 cores sampled from a 1300 m section of the drill hole. The <span class="hlt">pore-water</span> samples were analyzed for major cations and anions, stable isotopes of <span class="hlt">water</span> and sulfate, dissolved and total carbon, and bioavailable iron. The results reveal a broad transition between freshwater and saline <span class="hlt">water</span> from 100 to 500 m depth in the postimpact sediment section, and an underlying synimpact section that is almost entirely filled with brine. The presence of brine in the lowermost postimpact section and the trend in dissolved chloride with depth suggest a transport process dominated by molecular diffusion and slow, compaction-driven, upward flow. Major ion results indicate residual effects of diagenesis from heating, and a pre-impact origin for the brine. High levels of dissolved organic carbon (6-95 mg/L) and the distribution of electron acceptors indicate an environment that may be favorable for microbial activity throughout the drilled section. The concentration and extent of the brine is much greater than had previously been observed, suggesting that its occurrence may be common in the inner crater. However, groundwater-flow conditions in the structure may reduce the saltwater-intrusion hazard associated with the brine. ?? 2009 The Geological Society of America.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2914028','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2914028"><span>An Overview of <span class="hlt">Marine</span> Biodiversity in United States <span class="hlt">Waters</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Fautin, Daphne; Dalton, Penelope; Incze, Lewis S.; Leong, Jo-Ann C.; Pautzke, Clarence; Rosenberg, Andrew; Sandifer, Paul; Sedberry, George; Tunnell, John W.; Abbott, Isabella; Brainard, Russell E.; Brodeur, Melissa; Eldredge, Lucius G.; Feldman, Michael; Moretzsohn, Fabio; Vroom, Peter S.; Wainstein, Michelle; Wolff, Nicholas</p> <p>2010-01-01</p> <p><span class="hlt">Marine</span> biodiversity of the United States (U.S.) is extensively documented, but data assembled by the United States National Committee for the Census of <span class="hlt">Marine</span> Life demonstrate that even the most complete taxonomic inventories are based on records scattered in space and time. The best-known taxa are those of commercial importance. Body size is directly correlated with knowledge of a species, and knowledge also diminishes with distance from shore and depth. Measures of biodiversity other than species diversity, such as ecosystem and genetic diversity, are poorly documented. Threats to <span class="hlt">marine</span> biodiversity in the U.S. are the same as those for most of the world: overexploitation of living resources; reduced <span class="hlt">water</span> quality; coastal development; shipping; invasive species; rising temperature and concentrations of carbon dioxide in the surface ocean, and other changes that may be consequences of global change, including shifting currents; increased number and size of hypoxic or anoxic areas; and increased number and duration of harmful algal blooms. More information must be obtained through field and laboratory research and monitoring that involve innovative sampling techniques (such as genetics and acoustics), but data that already exist must be made accessible. And all data must have a temporal component so trends can be identified. As data are compiled, techniques must be developed to make certain that scales are compatible, to combine and reconcile data collected for various purposes with disparate gear, and to automate taxonomic changes. Information on biotic and abiotic elements of the environment must be interactively linked. Impediments to assembling existing data and collecting new data on <span class="hlt">marine</span> biodiversity include logistical problems as well as shortages in finances and taxonomic expertise. PMID:20689852</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70156341','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70156341"><span>An overview of <span class="hlt">marine</span> biodiversity in United States <span class="hlt">waters</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fautin, Daphne G.; Delton, Penelope; Incze, Lewis S.; Leong, Jo-Ann C.; Pautzke, Clarence; Rosenberg, Andrew A.; Sandifer, Paul; Sedberry, George R.; Tunnell, John W.; Abbott, Isabella; Brainard, Russell E.; Brodeur, Melissa; Eldredge, Lucius G.; Feldman, Michael; Moretzsohn, Fabio; Vroom, Peter S.; Wainstein, Michelle; Wolff, Nicholas</p> <p>2010-01-01</p> <p><span class="hlt">Marine</span> biodiversity of the United States (U.S.) is extensively documented, but data assembled by the United States National Committee for the Census of <span class="hlt">Marine</span> Life demonstrate that even the most complete taxonomic inventories are based on records scattered in space and time. The best-known taxa are those of commercial importance. Body size is directly correlated with knowledge of a species, and knowledge also diminishes with distance from shore and depth. Measures of biodiversity other than species diversity, such as ecosystem and genetic diversity, are poorly documented. Threats to <span class="hlt">marine</span> biodiversity in the U.S. are the same as those for most of the world: overexploitation of living resources; reduced <span class="hlt">water</span> quality; coastal development; shipping; invasive species; rising temperature and concentrations of carbon dioxide in the surface ocean, and other changes that may be consequences of global change, including shifting currents; increased number and size of hypoxic or anoxic areas; and increased number and duration of harmful algal blooms. More information must be obtained through field and laboratory research and monitoring that involve innovative sampling techniques (such as genetics and acoustics), but data that already exist must be made accessible. And all data must have a temporal component so trends can be identified. As data are compiled, techniques must be developed to make certain that scales are compatible, to combine and reconcile data collected for various purposes with disparate gear, and to automate taxonomic changes. Information on biotic and abiotic elements of the environment must be interactively linked. Impediments to assembling existing data and collecting new data on <span class="hlt">marine</span> biodiversity include logistical problems as well as shortages in finances and taxonomic expertise.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18726245','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18726245"><span>Effect of sampling method on contaminant measurement in <span class="hlt">pore-water</span> and surface <span class="hlt">water</span> at two uranium operations: can method affect conclusions?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Robertson, Erin L; Liber, Karsten</p> <p>2009-08-01</p> <p>This paper describes a comparison of two methods of sediment <span class="hlt">pore-water</span> sampling and two methods of surface <span class="hlt">water</span> sampling that were used in a broader investigation of cause(s) of adverse effects on benthic invertebrate communities at two Saskatchewan uranium operations (Key Lake and Rabbit Lake). Variables measured and compared included pH, ammonia, DOC, and trace metals. The two types of sediment <span class="hlt">pore-water</span> samples that were compared are centrifuged and 0.45-microm filtered sediment core samples vs. 0.2-microm dialysis (peeper) samples. The two types of surface <span class="hlt">water</span> samples that were compared are 53-microm filtered Van Dorn horizontal beta samples vs. 0.2-microm dialysis (peeper) samples. Results showed that 62% of the sediment core <span class="hlt">pore</span> <span class="hlt">water</span> values were higher than the corresponding peeper <span class="hlt">pore-water</span> measurements, and that 63% of the Van Dorn surface <span class="hlt">water</span> measurements were lower than corresponding peeper surface <span class="hlt">water</span> measurements. Furthermore, only 24% and 14% of surface <span class="hlt">water</span> and <span class="hlt">pore-water</span> measurements, respectively, fell within +/-10% range of one another; 73% and 50%, respectively, fell within +/-50%. Although somewhat confounded by differences in filtering method, the observed differences are believed to primarily be related to small, vertical differences in the environment sampled. Despite observed differences in concentrations of toxicologically relevant variables generated by the different sampling methods, the weight of evidence (WOE) conclusions drawn from each set of exposure data on the possible cause(s) of in situ toxicity to Hyalella azteca from a related study were the same at each uranium operation. However, this concurrence was largely due to other dominant lines of evidence. The WOE conclusions at Key Lake were dominated by the toxicity response of H. azteca in relation to exposure chemistry, where as the WOE conclusions at Rabbit Lake were informed by exposure chemistry, the toxicological response of H. azteca, and whole-body contaminant</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70031443','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70031443"><span>Composition of <span class="hlt">pore</span> <span class="hlt">water</span> in lake sediments, research site "B", Osage County, Oklahoma: Implications for lake <span class="hlt">water</span> quality and benthic organisms</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Zielinski, R.A.; Herkelrath, W.N.; Otton, J.K.</p> <p>2007-01-01</p> <p>Shallow ground <span class="hlt">water</span> at US Geological Survey research site B in northeastern Oklahoma is contaminated with NaCl-rich brine from past and present oil production operations. Contaminated ground <span class="hlt">water</span> provides a potential source of salts, metals, and hydrocarbons to sediment and <span class="hlt">water</span> of adjacent Skiatook Lake. A former brine storage pit 10 m in diameter that is now submerged just offshore from site B provides an additional source of contamination. Cores of the upper 16-40 cm of lake sediment were taken at the submerged brine pit, near an offshore saline seep, and at a location containing relatively uncontaminated lake sediment. <span class="hlt">Pore</span> <span class="hlt">waters</span> from each 2-cm interval were separated by centrifugation and analyzed for dissolved anions, cations, and trace elements. High concentrations of dissolved Cl- in <span class="hlt">pore</span> <span class="hlt">waters</span> (200-5000 mg/L) provide the most direct evidence of contamination, and contrast sharply with an average value of only about 37 mg/L in Skiatook Lake. Chloride/Br- mass ratios of 220-240 in contaminated <span class="hlt">pore</span> <span class="hlt">waters</span> are comparable to values in contaminated well <span class="hlt">waters</span> collected onshore. Dissolved concentrations of Se, Pb, Cu and Ni in Cl--rich <span class="hlt">pore</span> <span class="hlt">waters</span> exceed current US Environmental Protection Agency criteria for probable toxicity to aquatic life. At the submerged brine storage pit, the increase of Cl- concentration with depth is consistent with diffusion-dominant transport from deeper contaminated sediments. Near the offshore saline seep, <span class="hlt">pore</span> <span class="hlt">water</span> Cl- concentrations are consistently high and vary irregularly with depth, indicating probable Cl- transport by layer-directed advective flow. Estimated annual contributions of Cl- to the lake from the brine storage pit (???20 kg) and the offshore seep (???9 kg) can be applied to any number of similar sources. Generous estimates of the number of such sources at site B indicate minimal impact on <span class="hlt">water</span> quality in the local inlet of Skiatook Lake. Similar methodologies can be applied at other sites of Na</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26490407','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26490407"><span>Changes in the <span class="hlt">water</span> quality conditions of Kuwait's <span class="hlt">marine</span> <span class="hlt">waters</span>: Long term impacts of nutrient enrichment.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Devlin, M J; Massoud, M S; Hamid, S A; Al-Zaidan, A; Al-Sarawi, H; Al-Enezi, M; Al-Ghofran, L; Smith, A J; Barry, J; Stentiford, G D; Morris, S; da Silva, E T; Lyons, B P</p> <p>2015-11-30</p> <p>This work analyses a 30 year <span class="hlt">water</span> quality data set collated from chemical analyses of Kuwait's <span class="hlt">marine</span> <span class="hlt">waters</span>. Spatial patterns across six sites in Kuwait Bay and seven sites located in the Arabian Gulf are explored and discussed in terms of the changing influences associated with point and diffuse sources. Statistical modelling demonstrated significant increases for dissolved nutrients over the time period. Kuwait <span class="hlt">marine</span> <span class="hlt">waters</span> have been subject to inputs from urban development, untreated sewage discharges and decreasing river flow from the Shatt al-Arab River. Chlorophyll biomass showed a small but significant reduction; the high sewage content of the coastal <span class="hlt">waters</span> from sewage discharges likely favouring the presence of smaller phytoplankton taxa. This detailed assessment of temporal data of the impacts of sewage inputs into Kuwait's coastal <span class="hlt">waters</span> establishes an important baseline permitting future assessments to be made as sewage is upgraded, and the river continues to be extracted upstream.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70011999','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70011999"><span>Gas hydrates (clathrates) causing <span class="hlt">pore-water</span> freshening and oxygen isotope fractionation in deep-<span class="hlt">water</span> sedimentary sections of terrigenous continental margins</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hesse, R.; Harrison, W.E.</p> <p>1981-01-01</p> <p>The occurrence of gas hydrates in deep-<span class="hlt">water</span> sections of the continental margins predicted from anomalous acoustic reflectors on seismic profiles has been confirmed by recent deep-sea drilling results. On the Pacific continental slope off Guatemala gas hydrates were brought up for the first time from two holes (497, 498A) drilled during Leg 67 of the DSDP in <span class="hlt">water</span> depths of 2360 and 5500 m, respectively. The hydrates occur in organic matter-rich Pleistocene to Miocene terrigenous sediments. In the hydrate-bearing zone a marked decrease in interstitial <span class="hlt">water</span> chlorinities was observed starting at about 10-20 m subbottom depth. <span class="hlt">Pore</span> <span class="hlt">waters</span> at the bottom of the holes (near 400 m subbottom) have as little as half the chlorinity of seawater (i.e. 9???). Similar, but less pronounced, trends were observed during previous legs of the DSDP in other hydrate-prone segments of the continental margins where recharge of fresh <span class="hlt">water</span> from the continent can be excluded (e.g. Leg 11). The crystallization of hydrates, like ice, excludes salt ions from the crystal structure. During burial the dissolved salts are separated from the solids. Subsidence results in a downward motion of the solids (including hydrates) relative to the <span class="hlt">pore</span> fluids. Thawing of hydrates during recovery releases fresh <span class="hlt">water</span> which is remixed with the <span class="hlt">pore</span> fluid not involved in hydrate formation. The volume of the latter decreases downhole thus causing downward decreasing salinity (chlorinity). Hydrate formation is responsible for oxygen isotope fractionation with 18O-enrichment in the hydrate explaining increasingly more positive ??18O values in the <span class="hlt">pore</span> fluids recovered (after hydrate dissociation) with depth. ?? 1981.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/391144','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/391144"><span>Acute toxicity of saline produced <span class="hlt">waters</span> to <span class="hlt">marine</span> organisms</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pillard, D.A.; Evans, J.M.; DuFresne, D.L.</p> <p>1996-11-01</p> <p>Produced <span class="hlt">waters</span> from oil and gas drilling operations are typically very saline, and may cause acute toxicity to <span class="hlt">marine</span> organisms due imbalances as well as to an excess or deficiency of to osmotic specific common ions. In order to better understand the relationship between toxicity and ion concentration, laboratory toxicity tests were conducted using mysid shrimp (Mysidopsis bahia), sheepshead minnow, (Cyprinodon variegatus), and inland silvemide (Menidia beryllina). For each species the ionic concentration of standard laboratory <span class="hlt">water</span> was proportionally increased or decreased to produce test solutions with a range of salinities. Individual ions (sodium, potassium, calcium, magnesium, strontium, chloride, bromide, sulfate, bicarbonate, and borate) were also manipulated to examine individual ion toxicity. Organisms were exposed for 48 hours. The three test species differ in their tolerance of salinity. Mysid shrimp show a marked decrease in survival at salinities less than approximately 5 ppt. Both fish species tolerated low salinity <span class="hlt">water</span>, however, silversides were less tolerant of saline <span class="hlt">waters</span> (salinity greater than 40 ppt). There were also significant differences in the responses of the organisms to different ions. The results show that salinity of the test solution may play an important role in the responses of the organisms to produced <span class="hlt">water</span> effluent. Predictable toxicity/ion relationships developed in this study can be used to estimate whether toxicity in produced <span class="hlt">water</span> is a result of common ions, salinity, or some other unknown toxicant.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23346958','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23346958"><span>Adsorption of carbon dioxide, methane, and their mixtures in porous carbons: effect of surface chemistry, <span class="hlt">water</span> content, and <span class="hlt">pore</span> disorder.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Billemont, Pierre; Coasne, Benoit; De Weireld, Guy</p> <p>2013-03-12</p> <p>The adsorption of carbon dioxide, methane, and their mixtures in nanoporous carbons in the presence of <span class="hlt">water</span> is studied using experiments and molecular simulations. Both the experimental and numerical samples contain polar groups that account for their partially hydrophilicity. For small amounts of adsorbed <span class="hlt">water</span>, although the shape of the adsorption isotherms remain similar, both the molecular simulations and experiments show a slight decrease in the CO2 and CH4 adsorption amounts. For large amounts of adsorbed <span class="hlt">water</span>, the experimental data suggest the formation of methane or carbon dioxide clathrates in agreement with previous work. In contrast, the molecular simulations do not account for the formation of such clathrates. Another important difference between the simulated and experimental data concerns the number of <span class="hlt">water</span> molecules that desorb upon increasing the pressure of carbon dioxide and methane. Although the experimental data indicate that <span class="hlt">water</span> remains adsorbed upon carbon dioxide and methane adsorption, the molecular simulations suggest that 40 to 75% of the initial amount of adsorbed <span class="hlt">water</span> desorbs with carbon dioxide or methane pressure. Such discrepancies show that differences between the simulated and experimental samples are crucial to account for the rich phase behavior of confined <span class="hlt">water</span>-gas systems. Our simulations for carbon dioxide-methane coadsorption in the presence of <span class="hlt">water</span> suggest that the <span class="hlt">pore</span> filling is not affected by the presence of <span class="hlt">water</span> and that adsorbed solution theory can be applied for pressures as high as 15 MPa.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70035576','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70035576"><span>Polar organic compounds in <span class="hlt">pore</span> <span class="hlt">waters</span> of the Chesapeake Bay impact structure, Eyreville core hole: Character of the dissolved organic carbon and comparison with drilling fluids</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Rostad, C.E.; Sanford, W.E.</p> <p>2009-01-01</p> <p><span class="hlt">Pore</span> <span class="hlt">waters</span> from the Chesapeake Bay impact structure cores recovered at Eyreville Farm, Northampton County, Virginia, were analyzed to characterize the dissolved organic carbon. After squeezing or centrifuging, a small volume of <span class="hlt">pore</span> <span class="hlt">water</span>, 100 ??L, was taken for analysis by electrospray ionization-mass spectrometry. Porewater samples were analyzed directly without filtration or fractionation, in positive and negative mode, for polar organic compounds. Spectra in both modes were dominated by low-molecular-weight ions. Negative mode had clusters of ions differing by -60 daltons, possibly due to increasing concentrations of inorganic salts. The numberaverage molecular weight and weight-average molecular weight values for the <span class="hlt">pore</span> <span class="hlt">waters</span> from the Chesapeake Bay impact structure are higher than those reported for other aquatic sources of natural dissolved organic carbon as determined by electrospray ionization-mass spectrometry. In order to address the question of whether drilling mud fluids may have contaminated the <span class="hlt">pore</span> <span class="hlt">waters</span> during sample collection, spectra from the <span class="hlt">pore</span> <span class="hlt">waters</span> were compared to spectra from drilling mud fluids. Ions indicative of drilling mud fluids were not found in spectra from the <span class="hlt">pore</span> <span class="hlt">waters</span>, indicating there was no detectable contamination, and highlighting the usefulness of this analytical technique for detecting potential contamination during sample collection. ?? 2009 The Geological Society of America.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21326079','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21326079"><span>Experimental Study on the pH of <span class="hlt">Pore</span> <span class="hlt">water</span> in Compacted Bentonite under Reducing Conditions with Electromigration</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Nessa, S.A.; Idemitsu, K.; Yamazaki, S.; Ikeuchi, H.; Inagaki, Y.; Arima, T.</p> <p>2008-07-01</p> <p>Compacted bentonite and carbon steel are considered a good buffer and over-pack materials in the repositories of high-level radioactive waste disposal. Sodium bentonite, Kunipia-F contains approximately 95 wt% of montmorillonite. Bentonites prominent properties of high swelling, sealing ability and cation exchange capacity provide retardation against the transport of radionuclides from the waste into the surrounding rocks in the repository and its properties determine the behavior of bentonite. In this regards, the pH of <span class="hlt">pore</span> <span class="hlt">water</span> in compacted bentonite is measured with pH test paper wrapped with semi-permeable membrane of collodion sheet under reducing conditions. On 30 days, the pH test paper in the experimental apparatus indicated that the pH of <span class="hlt">pore</span> <span class="hlt">water</span> in compacted bentonite is around 8.0 at saturated state. The carbon steel coupon is connected as the working electrode to the potentiostat and is held at a constant supplied potential between +300 and -300 mV vs. Ag/AgCl electrode for up to 7 days. During applying electromigration the pH of <span class="hlt">pore</span> <span class="hlt">water</span> in bentonite decreased and it reached 6.0{approx}6.0 on 7 days. The concentration of iron and sodium showed nearly complementary distribution in the bentonite specimen after electromigration. It is expected that iron could migrate as ferrous ion through the interlayer of montmorillonite replacing exchangeable sodium ions in the interlayer. Semi-permeable membrane of collodion sheet does not affect the color change of pH test paper during the experiment. (authors)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21595462','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21595462"><span>Predicting <span class="hlt">pore</span> <span class="hlt">water</span> EPA-34 PAH concentrations and toxicity in pyrogenic-impacted sediments using pyrene content.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Arp, Hans Peter H; Azzolina, Nicholas A; Cornelissen, Gerard; Hawthorne, Steven B</p> <p>2011-06-15</p> <p>Sediment and freely dissolved <span class="hlt">pore</span> <span class="hlt">water</span> concentrations of the U.S. Environmental Protection Agency's list of 34 alkyl and parent PAHs (EPA-34) were measured in 335 sediment samples from 19 different sites impacted by manufactured gas plants, aluminum smelters and other pyrogenic sources. The total EPA-34 freely dissolved <span class="hlt">pore</span> <span class="hlt">water</span> concentration, C(pw,EPA-34), expressed as toxic units (TU) is currently considered one of the most accurate measures to assess risk at such sites; however, it is very seldom measured. With this data set, we address how accurately C(pw,EPA-34) can be estimated using limited 16 parent PAH data (EPA-16) commonly available for such sites. An exhaustive statistical analysis of the obtained data validated earlier observations that PAHs with more than 3 rings are present in similar relative abundances and their partitioning behavior typically follows Raoult's law and models developed for coal tar. As a result, sediment and freely dissolved <span class="hlt">pore</span> <span class="hlt">water</span> concentrations of pyrene and other 3- and 4-ring PAHs exhibit good log-log correlations (r² > 0.8) to most individual EPA-34 PAHs and also to C(pw,EPA-34). Correlations improve further by including the ratio of high to low molecular weight PAHs, as 2-ring PAHs exhibit the most variability in terms of their relative abundance. The most practical result of the current work is that log C(pw,EPA-34) estimated by the recommended pyrene-based estimation techniques was similarly well correlated to % survival of the benthic amphipods Hyalella azteca and Leptocheirus plumulosus as directly measured log C(pw,EPA-34) values (n = 211). Incorporation of the presented C(pw,EPA-34) estimation techniques could substantially improve risk assessments and guidelines for sediments impacted by pyrogenic residues, especially when limited data are available, without requiring any extra data or measurement costs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.B13A0154K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.B13A0154K"><span>Radiocarbon Evidence for Active Turnover of <span class="hlt">Pore-Water</span> Dissolved Organic Carbon in the Methanogenic and Sulfate-Methane-Transition Zones of Santa Barbara Basin Sediments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Komada, T.; Li, H. L.; Cada, A. K.; Burdige, D.; Magen, C.; Chanton, J.; Grose, A. M.</p> <p>2014-12-01</p> <p>Diverse metabolic activities have been documented in the deep biosphere. However, how these activities affect carbon cycling in the subsurface, and how they in turn affect the <span class="hlt">marine</span> and global cycles of carbon are still unclear. Here we present natural-abundance 14C and 13C data from the uppermost 4.5 m of the sediments of the Santa Barbara Basin, California Borderland, showing active turnover of dissolved organic carbon (DOC) within, and immediately below, the sulfate-methane transition zone (SMTZ; ~1.25 m). DOC concentrations increased with depth throughout the core, indicating net production within the sediment column. Enhanced DOC production was observed near the sediment-<span class="hlt">water</span> interface, and also at ~30 cm below the SMTZ (~1.55 m). ∆14C values of DOC increased across the sediment-<span class="hlt">water</span> interface, then decreased with depth, consistent with net production of modern DOC near the sediment-<span class="hlt">water</span> interface, and input of 14C-depleted DOC from deeper horizons. An isotope mixing plot constructed with these data shows that the DOC diffusing upward at the base of the core is devoid of 14C, yet the DOC diffusing into and out of the SMTZ is relatively enriched (-460‰ and -300‰, respectively). This difference in 14C content of the DOC flux can only be reconciled if the following two are occurring within, and immediately below, the SMTZ: (1) >90% of the 14C-dead basal DOC flux is removed from the <span class="hlt">pore</span> <span class="hlt">water</span> (by, e.g., oxidation, fermentation, methanogenesis, precipitation), and (2) this DOC is replaced by material produced in this region at a rate that exceeds the upward basal flux. The 14C and 13C signatures suggest sedimentary organic matter to be the dominant source of DOC in process (2). Our data provide a unique insight into the active transformation of DOC and sedimentary organic matter in the subsurface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/1002893','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/1002893"><span>Temporal and vertical distribution of total ammonia nitrogen and un-ionized ammonia nitrogen in sediment <span class="hlt">pore</span> <span class="hlt">water</span> from the upper Mississippi River</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Frazier, Bradley E.; Naimo, Teresa J.; Sandheinrich, Mark B.</p> <p>1996-01-01</p> <p>We examined the temporal and vertical distribution of total ammonia nitrogen (TAN) and un-ionized ammonia nitrogen (NH3-N) in sediment <span class="hlt">pore</span> <span class="hlt">water</span> and compared the temporal patterns of TAN and NH3-N concentrations in overlying surface <span class="hlt">water</span> with those in <span class="hlt">pore</span> <span class="hlt">water</span>. <span class="hlt">Pore</span> <span class="hlt">water</span> was obtained by core extraction and subsequent centrifugation. We measured TAN concentrations and calculated NH3-N concentrations from February through October 1993 at four sites in Pool 8, upper Mississippi River, at depths of 0 to 4, 4 to 8, and 8 to 12 cm below the sediment-<span class="hlt">water</span> interface. Total ammonia nitrogen and NH3-N concentrations were significantly different among sampling dates (p = 0.0001) and sediment depths (p = 0.0001). Concentrations of TAN and NH3-N in surface <span class="hlt">water</span> were significantly less than those in <span class="hlt">pore</span> <span class="hlt">water</span> from all sediment depths (p < 0.05). Concentrations in <span class="hlt">pore</span> <span class="hlt">water</span> ranged from 0.07 to 4.0 mg TAN/L and less than 1 to 20 I?g NH3-N/L in winter, and from 0.07 to 10.0 mg TAN/L and 1 to 175 I?g NH3-N/L in summer; greatest concentrations were usually found in sediments 8 to 12 cm deep. Annual mean TAN concentrations were positively correlated with silt and volatile solids content and were negatively correlated with sand content. Because of the high variability of TAN and NH3-N concentrations in <span class="hlt">pore</span> <span class="hlt">water</span>, sediment toxicity studies should take into account the season and the depth at which sediments are obtained. The annual mean NH3-N concentration in <span class="hlt">pore</span> <span class="hlt">water</span> at one site (55 I?g/L) exceeded the concentration (30 I?g/L) demonstrated to inhibit growth of fingernail clams in laboratory studies. However, these concentrations apparently were not lethal, as evidenced by the presence of fingernail clams at this site.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ESASP.722E.194U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ESASP.722E.194U"><span>Mapping <span class="hlt">Marine</span> Macroalgae In Case 2 <span class="hlt">Waters</span> Using CHRIS PROBA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Uhl, Florian; Oppelt, Natascha; Bartsch, Inka</p> <p>2013-12-01</p> <p><span class="hlt">Marine</span> macroalgae fulfil an important role in coastal ecosystems providing food and habitat for wildlife. The impacts of climate change and increasing human encroachment exert significant pressures on coastal ecosystems. Monitoring of <span class="hlt">marine</span> macroalgae communities provides information on the state of habitats and their structural changes. At landscape scale airborne remote sensing became an acknowledged tool to monitor coastal vegetation; for an operational use of macroalgae mapping, however, satellite remote sensing has significant advantages. In this paper, we therefore analyse the performance of three approaches to assess sublitoral macroalgae communities in the turbid coastal <span class="hlt">waters</span> around the island of Helgoland (North Sea, Germany) using CHRIS/Proba and EnMAP-like data. A Slope Based Index Classification, which has already been successfully applied in Helgolands intertidal zone during low tide, performed best; it was able to map the presence of sublitoral macroalgae with high accuracy (>80%) for both sensors. However successful detection of macroalgae was only achievable in <span class="hlt">water</span> depths up to 2m.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/7000235','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/7000235"><span>Metabolic regulation of amino acid uptake in <span class="hlt">marine</span> <span class="hlt">waters</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kirchman, D.L.; Hodson, R.E.</p> <p>1986-03-01</p> <p>To determine the relationships among the processes of uptake, intracellular pool formation, and incorporation of amino acids into protein, the authors measured the uptake of dipeptides and free amino acids by bacterial assemblages in estuarine and coastal <span class="hlt">waters</span> of the southeast US. The dipeptide phenylalanyl-phenylalanine (phe-phe) lowered V/sub max/ of phenylalanine uptake when the turnover rate of phenylalanine was relatively high. When the turnover rate was relatively low, phe-phe either had no effect or increased V/sub max/ of phenylalanine uptake. An analytical model was developed and tested to measure the turnover time of the intracellular pool of phenylalanine. The results suggested that the size of the intracellular pool is regulated, which precludes high assimilation rates of both phenylalanine and phe-phe. In <span class="hlt">waters</span> with relatively low phenylalanine turnover rates, bacterial assemblages appear to have a greater capacity to assimilate phenylalanine and phe-phe simultaneously. <span class="hlt">Marine</span> bacterial assemblages do not substantially increase the apparent respiration of amino acids when concentrations increase. The authors conclude that sustained increases in uptake rates and mineralization by <span class="hlt">marine</span> bacterial assemblages in response to an increase in the concentrations of dissolved organic nitrogen is determined by the rate of protein synthesis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4478152','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4478152"><span>Bi-Component T2* Analysis of Bound and <span class="hlt">Pore</span> Bone <span class="hlt">Water</span> Fractions Fails at High Field Strengths</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Seifert, Alan C.; Wehrli, Suzanne L.; Wehrli, Felix W.</p> <p>2015-01-01</p> <p>Osteoporosis involves degradation of bone’s trabecular architecture, cortical thinning, and enlargement of cortical <span class="hlt">pores</span>. Increased cortical porosity is a major cause of the decreased strength of osteoporotic bone. The majority of cortical <span class="hlt">pores</span>, however, are below the resolution limit of MRI. Recent work has shown that porosity can be evaluated by MRI-based quantification of bone <span class="hlt">water</span>. Bi-exponential T2* fitting and adiabatic inversion preparation are the two most common methods purported to distinguish bound and <span class="hlt">pore</span> <span class="hlt">water</span> in order to quantify matrix density and porosity. To assess the viability of T2* bi-component analysis as a method for quantifying bound and <span class="hlt">pore</span> <span class="hlt">water</span> fractions, we have applied this method to human cortical bone at 1.5T, 3T, 7T, and 9.4T, and validated the resulting pool fractions against μCT-derived porosity and gravimetrically-determined bone densities. We also investigated alternative methods: 2D T1–T2* bi-component fitting by incorporating saturation-recovery, 1D and 2D fitting of CPMG echo amplitudes, and deuterium inversion recovery. Short-T2* pool fraction was moderately correlated with porosity (R2 = 0.70) and matrix density (R2 = 0.63) at 1.5T, but the strengths of these associations were found to diminish rapidly as field strength increases, falling below R2 = 0.5 at 3T. Addition of the T1 dimension to bi-component analysis only slightly improved the strengths of these correlations. T2*-based bi-component analysis should therefore be used with caution. Performance of deuterium inversion-recovery at 9.4T was also poor (R2 = 0.50 versus porosity and R2 = 0.46 versus matrix density). CPMG-derived short-T2 fraction at 9.4T, however, is highly correlated with porosity (R2 = 0.87) and matrix density (R2 = 0.88), confirming the utility of this method for independent validation of bone <span class="hlt">water</span> pools. PMID:25981785</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1343742-linking-basin-scale-pore-scale-gas-hydrate-distribution-patterns-diffusion-dominated-marine-hydrate-systems-diffusion-driven-hydrate-growth-sands','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1343742-linking-basin-scale-pore-scale-gas-hydrate-distribution-patterns-diffusion-dominated-marine-hydrate-systems-diffusion-driven-hydrate-growth-sands"><span>Linking basin-scale and <span class="hlt">pore</span>-scale gas hydrate distribution patterns in diffusion-dominated <span class="hlt">marine</span> hydrate systems: DIFFUSION-DRIVEN HYDRATE GROWTH IN SANDS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Nole, Michael; Daigle, Hugh; Cook, Ann E.; ...</p> <p>2017-02-01</p> <p>The goal of this study is to computationally determine the potential distribution patterns of diffusion-driven methane hydrate accumulations in coarse-grained <span class="hlt">marine</span> sediments. Diffusion of dissolved methane in <span class="hlt">marine</span> gas hydrate systems has been proposed as a potential transport mechanism through which large concentrations of hydrate can preferentially accumulate in coarse-grained sediments over geologic time. Using one-dimensional compositional reservoir simulations, we examine hydrate distribution patterns at the scale of individual sand layers (1 to 20 m thick) that are deposited between microbially active fine-grained material buried through the gas hydrate stability zone (GHSZ). We then extrapolate to two- dimensional and basin-scalemore » three-dimensional simulations, where we model dipping sands and multilayered systems. We find that properties of a sand layer including <span class="hlt">pore</span> size distribution, layer thickness, dip, and proximity to other layers in multilayered systems all exert control on diffusive methane fluxes toward and within a sand, which in turn impact the distribution of hydrate throughout a sand unit. In all of these simulations, we incorporate data on physical properties and sand layer geometries from the Terrebonne Basin gas hydrate system in the Gulf of Mexico. We demonstrate that diffusion can generate high hydrate saturations (upward of 90%) at the edges of thin sands at shallow depths within the GHSZ, but that it is ineffective at producing high hydrate saturations throughout thick (greater than 10 m) sands buried deep within the GHSZ. As a result, we find that hydrate in fine-grained material can preserve high hydrate saturations in nearby thin sands with burial.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6218741','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6218741"><span><span class="hlt">Pore</span> <span class="hlt">water</span> chemistry of the mounds hydrothermal field, Galapagos Spreading Center: Results from Glomar Challenger piston coring</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bender, M.L.</p> <p>1983-02-10</p> <p>On DSDP Leg 70, Glomar Challenger piston cored hydrothermal MnO/sub 2/-encrusted nontronite mounds and adjacent pelagic sediments through to basement. <span class="hlt">Pore</span> <span class="hlt">waters</span> were collected by centrifuging, squeezing, and in situ sampling: analyses are presented here for Ca, Mg, Si, NH/sub 3/, Mn, and Fe. Our results confirm Maris and Bender's (1982) conclusions that hydrothermal solutions enriched in Ca by 1-2 mM and depleted in Mg by approx.2 mM are upwelling through the mounds and the surrounding pelagic sediments. Si, NH/sub 3/, and Mn/sup 2 +/ concentrations generally increase upcore, reflecting addition of products of metabolic reactions to upwelling hydrothermal solutions. <span class="hlt">Pore</span> <span class="hlt">water</span> iron concentrations decrease upcore, probably as a result of oxidation and precipitation of upwelling hydrothermal iron. The formation of nontronite (Fe(III)/sub 4/Si/sub 8/O/sub 20/(OH)/sub 4/) involves oxidation of dissolved Fe/sup 2 +/. Several models, constrained by the electron balance, are proposed to explain the process of nontronite formation. The stratigraphy of the mounds (thick nontronite covered by a thin MnO/sub 2/ crust) may be explained by postulating Fe/sup 2 +/ oxidation by MnO/sub 2/ and replacement of MnO/sub 2/ by nontronite at the base of the MnO/sub 2/ crust, followed by upward migration of Mn/sup 2 +/ and precipitation of MnO/sub 2/ at the sediment <span class="hlt">water</span> interface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/1997/0245/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/1997/0245/report.pdf"><span>Chemical data for bottom sediment, lake <span class="hlt">water</span>, bottom-sediment <span class="hlt">pore</span> <span class="hlt">water</span>, and fish in Mountain Creek Lake, Dallas, Texas, 1994-96</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Jones, S.A.; Van Metre, P.C.; Moring, J.B.; Braun, C.L.; Wilson, J.T.; Mahler, B.J.</p> <p>1997-01-01</p> <p>Mountain Creek Lake is a reservoir adjacent to two U.S. Department of the Navy facilities, the Naval Weapons Industrial Reserve Plant and the Naval Air Station in Dallas, Texas. A Resource Conservation and Recovery Act Facility Investigation found ground-<span class="hlt">water</span> plumes containing chlorinated solvents on both facilities. These findings led to a U.S. Geological Survey study of Mountain Creek Lake adjacent to both facilities between June 1994 and August 1996. Bottom sediments, lake <span class="hlt">water</span>, bottom-sediment <span class="hlt">pore</span> <span class="hlt">water</span>, and fish were collected for chemical analysis.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPS...331..462A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPS...331..462A"><span>Validation of <span class="hlt">pore</span> network simulations of ex-situ <span class="hlt">water</span> distributions in a gas diffusion layer of proton exchange membrane fuel cells with X-ray tomographic images</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Agaesse, Tristan; Lamibrac, Adrien; Büchi, Felix N.; Pauchet, Joel; Prat, Marc</p> <p>2016-11-01</p> <p>Understanding and modeling two-phase flows in the gas diffusion layer (GDL) of proton exchange membrane fuel cells are important in order to improve fuel cells performance. They are scientifically challenging because of the peculiarities of GDLs microstructures. In the present work, simulations on a <span class="hlt">pore</span> network model are compared to X-ray tomographic images of <span class="hlt">water</span> distributions during an ex-situ <span class="hlt">water</span> invasion experiment. A method based on watershed segmentation was developed to extract a <span class="hlt">pore</span> network from the 3D segmented image of the dry GDL. <span class="hlt">Pore</span> network modeling and a full morphology model were then used to perform two-phase simulations and compared to the experimental data. The results show good agreement between experimental and simulated microscopic <span class="hlt">water</span> distributions. <span class="hlt">Pore</span> network extraction parameters were also benchmarked using the experimental data and results from full morphology simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED239839.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED239839.pdf"><span>Wet Worlds: Explore the World of <span class="hlt">Water</span>. <span class="hlt">Marine</span> and Fresh <span class="hlt">Water</span> Activities for the Elementary Classroom.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Solomon, Gerard; And Others</p> <p></p> <p>Complete with student worksheets, field trip ideas, illustrations, vocabulary lists, suggested materials, and step-by-step procedures, the document presents a compilation of ideas for teaching elementary school (K-6) students about <span class="hlt">marine</span> and fresh <span class="hlt">water</span>. In the first unit students build miniature monuments and observe the deterioration of…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMOS33A2003P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMOS33A2003P"><span>In situ Determination of <span class="hlt">Pore-water</span> pH in Reducing Sediments near Methane Seeps and Vents by Laser Raman Spectroscopy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peltzer, E. T.; Walz, P. M.; Luna, M.; Zhang, X.; Brewer, P. G.</p> <p>2015-12-01</p> <p>Sediments near methane vents and seeps are often anoxic in nature due to the microbial oxidation of organic matter. When the <span class="hlt">pore-water</span> oxygen is consumed, the microbial population resorts to using sulfate as the terminal electron receptor. For the anaerobic oxidation of methane, the net reaction is: CH4 + SO42- = HCO3- + HS- + H2O. Hydrogen sulfide produced by this reaction dissociates into bisulfide in proportion to the <span class="hlt">pore-water</span> pH. Since the first pK of H2S is about 7 and close to the in situ <span class="hlt">pore-water</span> pH, it satisfies the criteria for a useful pH indicating dye. Although the two forms of hydrogen sulfide are not visually discernable by the human eye, these two forms have distinct Raman spectra and thus can be easily quantified using an in situ spectrometer. The relative Raman cross-sections of the hydrogen sulfide species were determined in the laboratory across a range of relevant pH values and at the approximate salinity (ionic strength) and temperature of deep-sea <span class="hlt">pore</span> <span class="hlt">waters</span>. With this calibration, it is simple to compute the <span class="hlt">pore-water</span> pH from the relative abundance of the two sulfide species: pH = pK1 + log10([HS-]/[H2S]). <span class="hlt">Pore-water</span> profiles were investigated at several sites in the Santa Monica basin around methane mounds, gas vents and cold seeps. A titanium <span class="hlt">pore-water</span> probe with a stainless steel frit was used to filter and collect <span class="hlt">pore-water</span> samples at 5-10 cm intervals in the top 50-60 cm of sediment. Filtration and collection of the <span class="hlt">pore-water</span> samples was usually accomplished in 5-10 minutes, with acquisition of the laser Raman spectra requiring only 2-4 minutes additional time. Vertical profiles of sulfate, total sulfide (H2S + HS-), methane and pH were collected simultaneously using the laser Raman spectrometer and <span class="hlt">pore-water</span> profile sampler. Sulfate was observed to decrease from seawater concentrations to below detection limits while both methane and total sulfide increased proportionally to the sulfate loss. Once total sulfide concentrations</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19926207','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19926207"><span>In situ measurement of soil moisture and <span class="hlt">pore-water</span> pressures in an 'incipient' landslide: Lake Tutira, New Zealand.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hawke, Richard; McConchie, Jack</p> <p>2011-02-01</p> <p>The immediate cost of shallow regolith landslides in New Zealand has been estimated to exceed US$33M annually. Since the majority of these landslides occur during prolonged wet conditions, or intense rainstorms, moisture conditions are a critical control. The nature, dynamics, and character of soil moisture conditions, and the piezometric response to rainfall, have been recorded within an 'incipient' landslide for more than 5 years. The study site, on pastoral hill country within the Lake Tutira catchment in northern Hawkes Bay, is typical of large areas of New Zealand episodically affected by extensive landsliding. Detailed continuous measurements show that both the soil moisture and piezometric response within the regolith are highly storm- and site-specific. The development of positive <span class="hlt">pore</span> pressures is infrequent; they form only during intense rainstorms, and persist for a short time. The hydraulic response of the soil is primarily a function of storm characteristics, but this response can be modified by antecedent moisture conditions, topographic position, and heterogeneity of soil properties. Stability analysis shows that most slopes in the study area are significantly steeper than can be explained by the frictional strength of the regolith. Measured hydraulic conditions also show that positive <span class="hlt">pore-water</span> pressures alone do not trigger slope instability. A recent slope failure followed a period of extremely high antecedent moisture conditions, and occurred when maximum soil moisture conditions, though not <span class="hlt">pore-water</span> pressures, were recorded. Increased moisture content of the regolith reduces matric tension, and therefore effective cohesion of the soil. This cohesion is critical to maintaining stability of the regolith on these slopes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16..158B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16..158B"><span>Comparison between monitored and modeled <span class="hlt">pore</span> <span class="hlt">water</span> pressure and safety factor in a slope susceptible to shallow landslides</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bordoni, Massimiliano; Meisina, Claudia; Zizioli, Davide; Valentino, Roberto; Bittelli, Marco; Chersich, Silvia</p> <p>2014-05-01</p> <p>Shallow landslides can be defined as slope movements affecting superficial deposits of small thicknesses which are usually triggered due to extreme rainfall events, also very concentrated in time. Shallow landslides are hazardous phenomena: in particular, if they happen close to urbanized areas they could cause significant damages to cultivations, structures, infrastructures and, sometimes, human losses. The triggering mechanism of rainfall-induced shallow landslides is strictly linked with the hydrological and mechanical responses of usually unsaturated soils to rainfall events. For this reason, it is fundamental knowing the intrinsic hydro-mechanical properties of the soils in order to assess both susceptibility and hazard of shallow landslide and to develop early-warning systems at large scale. The hydrological data collected by a 20 months monitoring on a slope susceptible to shallow landslides in an area of the North -Eastern Oltrepo Pavese (Northern Apennines, Italy) were used to identify the hydrological behaviors of the investigated soils towards rainfall events. Field conditions under different rainfall trends have also been modeled by using both hydrological and physically-based stability models for the evaluation of the slope safety factor . The main objectives of this research are: (a) to compare the field measured <span class="hlt">pore</span> <span class="hlt">water</span> pressures at different depths with results of hydrological models, in order to evaluate the efficiency of the tested models and to determine how precipitations affect <span class="hlt">pore</span> pressure development; (b) to compare the time trends of the safety factor that have been obtained by applying different stability models; (c) to evaluate, through a sensitivity analysis, the effects of soil hydrological properties on modeling <span class="hlt">pore</span> <span class="hlt">water</span> pressure and safety factor. The test site slope where field measurements were acquired is representative of other sites in Northern Apennines affected by shallow landslides and is characterized by medium</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22619072','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22619072"><span>Using in situ <span class="hlt">pore</span> <span class="hlt">water</span> concentrations to estimate the phytotoxicity of nicosulfuron in soils to corn (Zea mays L.).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Kailin; Cao, Zhengya; Pan, Xiong; Yu, Yunlong</p> <p>2012-08-01</p> <p>The phytotoxicity of an herbicide in soil is typically dependent on the soil characteristics. To obtain a comparable value of the concentration that inhibits growth by 50% (IC50), 0.01 M CaCl(2) , excess <span class="hlt">pore</span> <span class="hlt">water</span> (EPW) and in situ <span class="hlt">pore</span> <span class="hlt">water</span> (IPW) were used to extract the bioavailable fraction of nicosulfuron from five different soils to estimate the nicosulfuron phytotoxicity to corn (Zea mays L.). The results indicated that the phytotoxicity of nicosulfuron in soils to corn depended on the soil type, and the IC50 values calculated based on the amended concentration of nicosulfuron ranged from 0.77 to 9.77 mg/kg among the five tested soils. The range of variation in IC50 values for nicosulfuron was smaller when the concentrations of nicosulfuron extracted with 0.01 M CaCl(2) and EPW were used instead of the amended concentration. No significant difference was observed among the IC50 values calculated from the IPW concentrations of nicosulfuron in the five tested soils, suggesting that the concentration of nicosulfuron in IPW could be used to estimate the phytotoxicity of residual nicosulfuron in soils.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22233919','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22233919"><span>Assessment of sediment quality and <span class="hlt">pore</span> <span class="hlt">water</span> ecotoxicity in Kebir Rhumel basin (NE-Algeria): a combined approach.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sahli, Leila; Afri-Mehennaoui, Fatima-Zohra; El Hadef El Okki, Mohamed; Férard, Jean François; Mehennaoui, Smail</p> <p>2012-01-01</p> <p>The objectives of this study are to use different approaches to assess the current pollution status in the wadis of the Kebir Rhumel basin. First, sediment trace metal contents were measured by flame atomic absorption spectroscopy. Then, sediment quality was assessed on the basis of contamination assessment indexes such as: Geoaccumulation Index (Igeo), Contamination factor (C(f)), Contamination degree (C(d)), Sediment Pollution Index (SPI) and SEQ guidelines (Consensus Sediment Quality Guidelines). In addition, several toxicity tests (Daphnia magna mobility inhibition acute test-48 h, Aliivibrio fischeri luminescence inhibition acute test - 15/30 mn and Pseudokirchneriella subcapitata growth inhibition chronic test - 72 h) were conducted to assess sediment <span class="hlt">pore</span> <span class="hlt">water</span> ecotoxicity. Trace metal concentrations followed the order: Mn > Zn > Pb > Cr > Cu > Ni > Co > Cd. Indexes used indicate varying degrees of sediment quality. Igeo, C(f), C(d) and SPI reveal a polymetallic contamination dominated by two or more elements in which Cd, Cu and Pb are of greatest concern. SEQ guidelines showed that biological effects on fauna would likely be observed occasionally and/or frequently for Cd, Cr, Cu, Pb and Zn contents. Test organisms exposed to sediment <span class="hlt">pore</span> <span class="hlt">water</span> showed that the algal P. subcapitata test was more sensitive than the D. magna and A. fischeri tests. Hence, algal growth inhibition proved to be the most sensitive response to contaminants present in sediment extracts but a significant relationship with trace metal contents was not demonstrated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=203992','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=203992"><span>Survival of Candida albicans in tropical <span class="hlt">marine</span> and fresh <span class="hlt">waters</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Valdes-Collazo, L; Schultz, A J; Hazen, T C</p> <p>1987-01-01</p> <p>A survey of Candida albicans indicated that the organism was present at all sites sampled in a rain forest stream and in near-shore coastal <span class="hlt">waters</span> of Puerto Rico. In the rain forest watershed no relationship existed between densities of fecal coliforms and densities of C. albicans. At two pristine sites in the rain forest watershed both C. albicans and Escherichia coli survived in diffusion chambers for extended periods of time. In near-shore coastal <span class="hlt">waters</span> C. albicans and E. coli survival times in diffusion chambers were enhanced by effluent from a rum distillery. The rum distillery effluent had a greater effect on E. coli than on C. albicans survival in the diffusion chambers. These studies show that neither E. coli nor C. albicans organisms are good indicators of recent fecal contamination in tropical <span class="hlt">waters</span>. It further demonstrates that pristine freshwater environments and <span class="hlt">marine</span> <span class="hlt">waters</span> receiving organic loading in the tropics can support densities of C. albicans which may be a health hazard. Images PMID:3310885</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4169402','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4169402"><span>Importance of Boreal Rivers in Providing Iron to <span class="hlt">Marine</span> <span class="hlt">Waters</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kritzberg, Emma S.; Bedmar Villanueva, Ana; Jung, Marco; Reader, Heather E.</p> <p>2014-01-01</p> <p>This study reports increasing iron concentrations in rivers draining into the Baltic Sea. Given the decisive role of iron to the structure and biogeochemical function of aquatic ecosystems, this trend is likely one with far reaching consequences to the receiving system. What those consequences may be depends on the fate of the iron in estuarine mixing. We here assess the stability of riverine iron by mixing <span class="hlt">water</span> from seven boreal rivers with artificial sea salts. The results show a gradual loss of iron from suspension with increasing salinity. However, the capacity of the different river <span class="hlt">waters</span> to maintain iron in suspension varied greatly, i.e. between 1 and 54% of iron was in suspension at a salinity of 30. The variability was best explained by iron:organic carbon ratios in the riverine <span class="hlt">waters</span> – the lower the ratio the more iron remained in suspension. <span class="hlt">Water</span> with an initially low iron:organic carbon ratio could keep even higher than ambient concentrations of Fe in suspension across the salinity gradient, as shown in experiments with iron amendments. Moreover, there was a positive relationship between the molecular size of the riverine organic matter and the amount of iron in suspension. In all, the results point towards a remarkably high transport capacity of iron from boreal rivers, suggesting that increasing concentrations of iron in river mouths may result in higher concentrations of potentially bioavailable iron in the <span class="hlt">marine</span> system. PMID:25233197</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeoJI.203.1072B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeoJI.203.1072B"><span>The electrical conductivity of CO2-bearing <span class="hlt">pore</span> <span class="hlt">waters</span> at elevated pressure and temperature: a laboratory study and its implications in CO2 storage monitoring and leakage detection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Börner, Jana H.; Herdegen, Volker; Repke, Jens-Uwe; Spitzer, Klaus</p> <p>2015-11-01</p> <p>The electrical rock conductivity is a sensitive indicator for carbon dioxide (CO2) injection and migration processes. For a reliable balancing of the free CO2 in <span class="hlt">pore</span> space with petrophysical models such as Archie's law or for the detection of migrating CO2, detailed knowledge of the <span class="hlt">pore</span> <span class="hlt">water</span> conductivity during interaction with CO2 is essential but not available yet. Contrary to common assumptions, <span class="hlt">pore</span> <span class="hlt">water</span> conductivity cannot be assumed constant since CO2 is a reactive gas that dissolves into the <span class="hlt">pore</span> <span class="hlt">water</span> in large amounts and provides additional charge carriers due to the dissociation of carbonic acid. We consequently carried out systematic laboratory experiments to quantify and analyse the changes in saline <span class="hlt">pore</span> <span class="hlt">water</span> conductivity caused by CO2 at thermodynamic equilibrium. Electrical conductivity is measured on <span class="hlt">pore</span> <span class="hlt">water</span> samples for pressures up to 30 MPa and temperatures up to 80 °C. The parameter range covers the gaseous, liquid and supercritical state of the CO2 involved. <span class="hlt">Pore</span> <span class="hlt">water</span> salinities from 0.006 up to 57.27 g L-1 sodium chloride were investigated as well as selective other ion species. At the same time, the CO2 concentration in the salt solution was determined by a wet-chemical procedure. A two-regime behaviour appears: for small salinities, we observe an increase of up to more than factor 3 in the electrical <span class="hlt">pore</span> <span class="hlt">water</span> conductivity, which strongly depends on the solution salinity (low-salinity regime). This is an expected behaviour, since the additional ions originating from the dissociation of carbonic acid positively contribute to the solution conductivity. However, when increasing salinities are considered this effect is completely diminished. For highly saline solutions, the increased mutual impeding causes the mobility of all ions to decrease, which may result in a significant reduction of conductivity by up to 15 per cent despite the added CO2 (high-salinity regime). We present the data set covering the pressure, temperature, salinity</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMOS52B..02P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMOS52B..02P"><span>In situ Measurement of <span class="hlt">Pore-Water</span> pH in Anoxic Sediments Using Laser Raman Spectrometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peltzer, E. T.; Luna, M.; Walz, P. M.; Zhang, X.; Brewer, P. G.</p> <p>2010-12-01</p> <p>Accurate measurement of the geochemical properties of sediment <span class="hlt">pore</span> <span class="hlt">waters</span> is of fundamental importance in ocean geochemistry and microbiology. Recent work has shown that the properties of <span class="hlt">pore</span> <span class="hlt">waters</span> can be measured rapidly in situ with a novel Raman based insertion probe (Zhang et al., 2010), and that data obtained from anoxic sediments on in situ dissolved methane concentrations are very different (~30x) than from recovered cores due the large scale degassing that occurs during core recovery (Zhang et al., submitted). Degassing of methane must carry with it via Henry’s Law partioning significant quantities of H2S, which is clearly detectable by smell during sample processing, and thus in situ measurement of H2S is also highly desirable. In practice, dissolved H2S is partitioned between the HS- and H2S species as a function of pH with pKa ~7 for the acid dissociation reaction. Since both species are Raman active full determination of the sulfide system is possible if the relative Raman cross sections are known. The diagenetic equations for these reactions are commonly summarized as: 2CH2O + SO4= ↔ 2HCO3- + H2S CH4 + SO4= ↔ HCO3- + HS- + H2O Three of the major components of these equations, CH4, SO4=, and H2S/HS-, are all observable directly by Raman spectroscopy; but the detection of HCO3- presents a challenge due to its low Raman cross section and thus poor sensitivity. We show that <span class="hlt">pore</span> <span class="hlt">water</span> pH, which is a good estimator of HCO3- if total CO2 or alkalinity are known, can be measured by observing the H2S / HS- ratio via the equation: pH = pKa + log([HS-]/[H2S]) thereby fully constraining these equations within a single measurement protocol. The Raman peak for HS- is at 2573 cm-1 and for H2S is at 2592 cm-1; thus the peaks are well separated and may easily be deconvoluted from the observed spectrum. We have determined the relative Raman cross sections by a series of laboratory measurements over a range of pH and by using the definition that when pH = p</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70019626','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70019626"><span>The Determination of Metals in Sediment <span class="hlt">Pore</span> <span class="hlt">Waters</span> and in 1N HCl-Extracted Sediments by ICP-MS</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>May, T.W.; Wiedmeyer, Ray H.; Brumbaugh, W.G.; Schmitt, C.J.</p> <p>1997-01-01</p> <p>Concentrations of metals in sediment interstitial <span class="hlt">water</span> (<span class="hlt">pore</span> <span class="hlt">water</span>) and those extractable from sediment with weak acids can provide important information about the bioavailability and toxicological effects of such contaminants. The highly variable nature of metal concentrations in these matrices requires instrumentation with the detection limit capability of graphite furnace atomic absorption and the wide dynamic linear range capability of ICP-OES. These criteria are satisfied with ICP-MS instrumentation. We investigated the performance of ICP-MS in the determination of certain metals from these matrices. The results for three metals were compared to those determined by graphite furnace atomic absorption spectroscopy. It was concluded that ICP-MS was an excellent instrumental approach for the determination of metals in these matrices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1134080','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1134080"><span>2014 <span class="hlt">Water</span> Power Program Peer Review: <span class="hlt">Marine</span> and Hydrokinetic Technologies, Compiled Presentations (Presentation)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Not Available</p> <p>2014-02-01</p> <p>This document represents a collection of all presentations given during the EERE Wind and <span class="hlt">Water</span> Power Program's 2014 <span class="hlt">Marine</span> and Hydrokinetic Peer Review. The purpose of the meeting was to evaluate DOE-funded hydropower and <span class="hlt">marine</span> and hydrokinetic R&D projects for their contribution to the mission and goals of the <span class="hlt">Water</span> Power Program and to assess progress made against stated objectives.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=marine+AND+biology+AND+career&pg=3&id=ED236325','ERIC'); return false;" href="http://eric.ed.gov/?q=marine+AND+biology+AND+career&pg=3&id=ED236325"><span>Competency-Based Curriculum for Prevocational Exploration. <span class="hlt">Marine</span>/Fresh <span class="hlt">Water</span>.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Reese, Clara C.</p> <p></p> <p>This competency-based curriculum is intended to help teachers of prevocational career exploration courses in West Virginia to present information about <span class="hlt">marine</span>/fresh <span class="hlt">water</span> occupations. The document is organized into five units: fisheries, life sciences, <span class="hlt">marine</span> life cultivation, research, and <span class="hlt">water</span> vehicle operation. Each unit consists of five to 15…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=107520&keyword=Bivalves&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=90564317&CFTOKEN=94300855','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=107520&keyword=Bivalves&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=90564317&CFTOKEN=94300855"><span>IMPORTANCE OF INTERSTITIAL, OVERLYING <span class="hlt">WATER</span> AND WHOLE SEDIMENT EXPOSURES TO BIOACCUMUALTION BY <span class="hlt">MARINE</span> BIVALVES</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>During the performance of contaminated sediment studies using nonpolar pollutants, like polyclorinated biphenyls (PCBs), with <span class="hlt">marine</span> organisms, the routes of exposure can include whole sediment, overlying <span class="hlt">waters</span> and interstitial <span class="hlt">waters</span> (assuming no feeding). These routes can be f...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JHyd..544..195Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JHyd..544..195Z"><span><span class="hlt">Water</span> content dynamics at plot scale - comparison of time-lapse electrical resistivity tomography monitoring and <span class="hlt">pore</span> pressure modelling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zieher, Thomas; Markart, Gerhard; Ottowitz, David; Römer, Alexander; Rutzinger, Martin; Meißl, Gertraud; Geitner, Clemens</p> <p>2017-01-01</p> <p>Physically-based dynamic modelling of shallow landslide susceptibility rests on several assumptions and simplifications. However, the applicability of physically-based models is only rarely tested in the field at the appropriate scale. This paper presents results of a spray irrigation experiment conducted on a plot of 100 m2 on an Alpine slope susceptible to shallow landsliding. Infiltrating precipitation applied at a constant rate (27.5 mm/h for 5.3 h) was monitored by means of 2D time-lapse electrical resistivity tomography, combined with time-domain reflectometry sensors installed at various depths. In addition, regolith characteristics were assessed by dynamic cone penetration tests using a light-weight cone penetrometer. The spray irrigation experiment resulted in a vertically progressing wetting front to a depth of 80-100 cm. Below that, the unconsolidated material was already saturated by rainfall in the previous days. The observed mean resistivity reduction attributed to infiltrating <span class="hlt">water</span> during irrigation was scaled to pressure head. Mean variations in <span class="hlt">pore</span> pressure were reproduced by a linear diffusion model also used in physically-based dynamic landslide susceptibility modelling. Sensitive parameters (hydraulic conductivity and specific storage) were tested over selected value ranges and calibrated. Calibrated parameter values are within published and experimentally derived ranges. The results of the comparison of observations and model results suggest that the model is capable of reproducing mean changes of <span class="hlt">pore</span> pressure at a suitable scale for physically-based modelling of shallow landslide susceptibility. However, small-scale variations in <span class="hlt">pore</span> pressure that may facilitate the triggering of shallow landslides are not captured by the model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.H33L..04D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.H33L..04D"><span><span class="hlt">Pore</span> characteristics and their emergent effect on <span class="hlt">water</span> adsorption and transport in clays using small-angle neutron scattering with contrast variation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ding, M.; Hartl, M.; Wang, Y.; Hjelm, R.</p> <p>2013-12-01</p> <p>In nuclear waste management, clays are canonical materials in the construction of engineered barriers. They are also naturally occurring reactive minerals which play an important role in retention and colloidal facilitated reactive transport in subsurface systems. Knowledge of total and accessible porosity in clays is crucial in determining fluids transport behavior in clays. It will provide fundamental insight on the performance efficiency of specific clays as a barrier material and their role in regulating radionuclide transport in subsurface environments. The aim of the present work is to experimentally investigate the change in <span class="hlt">pore</span> characteristics of clays as function of moisture content, and to determine their <span class="hlt">pore</span> character in relation to their <span class="hlt">water</span> retention capacity. Recent developments in small-angle neutron scattering (SANS) techniques allow quantitative measurement of <span class="hlt">pore</span> morphology and size distribution of various materials in their pristine state under various sample environments (exposure to solution, high temperature, and so on). Furthermore, due to dramatic different neutron scattering properties of hydrogen and deuterium, one can readily use contrast variation, which is the isotopic labeling with various ratios of H and D (e.g. mixture of H2O/D2O) to highlight or suppress features of the sample. This is particularly useful in the study of complex <span class="hlt">pore</span> system such as clays. In this study, we have characterized the <span class="hlt">pore</span> structures for a number of clays including clay minerals and field samples which are relevant to high-level waste systems under various sample environments (e.g., humidity, temperature and pressure) using SANS. Our results suggest that different clays show unique <span class="hlt">pore</span> features under various sample environments. To distinguish between accessible/non-accessible <span class="hlt">pores</span> and the nature of <span class="hlt">pore</span> filling (e.g. the quantity of H2O adsorbed by clays, and the distribution of H2O in relation to <span class="hlt">pore</span> character) to <span class="hlt">water</span>, clays were exposed for</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24268236','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24268236"><span>Exploitation of 3D face-centered cubic mesoporous silica as a carrier for a poorly <span class="hlt">water</span> soluble drug: influence of <span class="hlt">pore</span> size on release rate.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhu, Wenquan; Wan, Long; Zhang, Chen; Gao, Yikun; Zheng, Xin; Jiang, Tongying; Wang, Siling</p> <p>2014-01-01</p> <p>The purposes of the present work were to explore the potential application of 3D face-centered cubic mesoporous silica (FMS) with <span class="hlt">pore</span> size of 16.0nm as a delivery system for poorly soluble drugs and investigate the effect of <span class="hlt">pore</span> size on the dissolution rate. FMS with different <span class="hlt">pore</span> sizes (16.0, 6.9 and 3.7nm) was successfully synthesized by using Pluronic block co-polymer F127 as a template and adjusting the reaction temperatures. Celecoxib (CEL), which is a BCS class II drug, was used as a model drug and loaded into FMS with different <span class="hlt">pore</span> sizes by the solvent deposition method at a drug-silica ratio of 1:4. Characterization using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transformation infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), nitrogen adsorption, X-ray diffraction (XRD), and differential scanning calorimetry (DSC) was used to systematically investigate the drug loading process. The results obtained showed that CEL was in a non-crystalline state after incorporation of CEL into the <span class="hlt">pores</span> of FMS-15 with <span class="hlt">pore</span> size of 16.0nm. In vitro dissolution was carried out to demonstrate the effects of FMS with different <span class="hlt">pore</span> sizes on the release of CEL. The results obtained indicated that the dissolution rate of CEL from FMS-15 was significantly enhanced compared with pure CEL. This could be explained by supposing that CEL encountered less diffusion resistance and its crystallinity decreased due to the large <span class="hlt">pore</span> size of 16.0nm and the nanopore channels of FMS-15. Moreover, drug loading and <span class="hlt">pore</span> size both play an important role in enhancing the dissolution properties for the poorly <span class="hlt">water</span>-soluble drugs. As the <span class="hlt">pore</span> size between 3.7 and 16.0nm increased, the dissolution rate of CEL from FMS gradually increased.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JCrGr.345...61J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JCrGr.345...61J"><span>Hydrate formation and growth in <span class="hlt">pores</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jung, Jong-Won; Santamarina, J. Carlos</p> <p>2012-04-01</p> <p>Gas hydrates consist of guest gas molecules encaged in <span class="hlt">water</span> cages. Methane hydrate forms in <span class="hlt">marine</span> and permafrost sediments. In this study, we use optical, mechanical and electrical measurements to monitor hydrate formation and growth in small <span class="hlt">pores</span> to better understand the hydrate <span class="hlt">pore</span> habit in hydrate-bearing sediments. Hydrate formation in capillary tubes exposes the complex and dynamic interactions between nucleation, gas diffusion and gas solubility. The observation of hydrate growth in a droplet between transparent plates shows that the hydrate shell does not grow homogeneously but advances in the form of lobes that invade the <span class="hlt">water</span> phase; in fact, the hydrate shell must be discontinuous and possibly cracked to justify the relatively fast growth rates observed in these experiments. Volume expansion during hydrate formation causes <span class="hlt">water</span> to flow out of menisci; expelled <span class="hlt">water</span> either spreads on the surface of <span class="hlt">water</span>-wet substrates and forms a thin hydrate sheet, or remains next to menisci when substrates are oil-wet. Hydrate formation is accompanied by ion exclusion, yet, there is an overall increase in electrical resistance during hydrate formation. Hydrate growth may become salt-limited in trapped <span class="hlt">water</span> conditions; in this case, aqueous brine and gas CH4 may be separated by hydrate and the three-phase system remains stable within the <span class="hlt">pore</span> space of sediments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/AD1018837','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/AD1018837"><span>Dredged Material Evaluations: Review of Zooplankton Toxicity Test Methods for <span class="hlt">Marine</span> <span class="hlt">Water</span> Quality Evaluations</span></a></p> <p><a target="_blank" href="https://publicaccess.dtic.mil/psm/api/service/search/search">DTIC Science & Technology</a></p> <p></p> <p>2016-09-01</p> <p>Toxicity Test Methods for <span class="hlt">Marine</span> <span class="hlt">Water</span> Quality Evaluations by Alan J Kennedy, Guilherme Lotufo, Jennifer G. Laird, and J. Daniel Farrar PURPOSE: The...first objective of this Dredging Operations and Engineering (DOER) technical note is to summarize currently available estuarine and <span class="hlt">marine</span> <span class="hlt">water</span> ...suitable for unrestricted open <span class="hlt">water</span> placement, beneficial use, or if management strategies are necessary. Open <span class="hlt">water</span> placement of DM into inland</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4177409','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4177409"><span>Environmental Quality of Italian <span class="hlt">Marine</span> <span class="hlt">Water</span> by Means of <span class="hlt">Marine</span> Strategy Framework Directive (MSFD) Descriptor 9</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Maggi, Chiara; Lomiri, Serena; Di Lorenzo, Bianca; d’Antona, Marco; Berducci, Maria Teresa</p> <p>2014-01-01</p> <p>ISPRA, on behalf of the Italian Ministry of Environment, carried out the initial assessment of environmental quality status of the 3 Italian subregions (Mediterranean Sea Region) on Descriptor 9. The approach adopted to define the GES started to verify that contaminants in fish and other seafood for human consumption did not exceed levels established by Community legislation (Reg. 1881/2006 and further updates). As the <span class="hlt">Marine</span> Strategy Framework Directive (MSFD) requires to use health tools to assess the environment, Italy decided to adopt a statistical range of acceptance of thresholds identified by national (D.Lgs. 152/2006 concerning <span class="hlt">water</span> quality required for mussel farms) and international legislation (Reg. 1881/2006 and further updates), which allowed to use the health results and to employ them for the assessment of environmental quality. Italy proposed that Good Environmental Status (GES) is achieved when concentrations are lower than statistical range of acceptance, estimated on samples of fish and fishery products coming from only national <span class="hlt">waters</span>. GIS-based approach a to perform different integration levels for station, cell’s grid and years, was used; the elaborations allowed to judge the environmental quality good. PMID:25251745</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21516994','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21516994"><span>Influence of flooding and vegetation on carbon, nitrogen, and phosphorus dynamics in the <span class="hlt">pore</span> <span class="hlt">water</span> of a Spartina alterniflora salt marsh.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Negrin, Vanesa L; Spetter, Carla V; Asteasuain, Raúl O; Perillo, Gerardo M E; Marcovecchio, Jorge E</p> <p>2011-01-01</p> <p>Four sites were selected in a salt marsh in the Bahia Blanca Estuary (Argentina): (1) low marsh (flooded by the tide twice daily) vegetated by S. alterniflora; (2) non-vegetated low marsh; (3) high marsh (flooded only in spring tides) vegetated by S. alterniflora; (4) non-vegetated high marsh. The pH and Eh were measured in sediments, while dissolved nutrients (ammonium, nitrate, nitrite and phosphate) and particulate organic matter (POM) were determined in <span class="hlt">pore</span> <span class="hlt">water</span>. pH (6.2-8.7) was only affected by vegetation in low areas. Eh (from -300 to 250 mV) was lower at low sites than at high ones; in the latter, the values were higher in the non-vegetated sediments. The POM concentration was greater in the high marsh than in the low marsh, with no effect of vegetation. Ammonium was the most abundant nitrogen nutrient species in <span class="hlt">pore</span> <span class="hlt">water</span>, except in the non-vegetated high marsh where nitrate concentration was higher. All nitrogen nutrients were affected by both flooding and vegetation. Phosphate was always present in <span class="hlt">pore</span> <span class="hlt">water</span> at all sites throughout the year and its concentration varied within narrow limits, with no effect of flooding and greater values always at non-vegetated sites. Our results showed that the variability of the <span class="hlt">pore</span> <span class="hlt">water</span> composition within the marsh is greater than the temporal variation, meaning that both tidal flooding and vegetation are important in the dynamics of nutrients and organic matter in the sediment <span class="hlt">pore</span> <span class="hlt">water</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21966906','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21966906"><span>An ectobiont-bearing foraminiferan, Bolivina pacifica, that inhabits microxic <span class="hlt">pore</span> <span class="hlt">waters</span>: cell-biological and paleoceanographic insights.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bernhard, Joan M; Goldstein, Susan T; Bowser, Samuel S</p> <p>2010-08-01</p> <p>The presence of tests (shells) in foraminifera could be taken as an indicator that this protist taxon is unlikely to possess ectosymbionts. Here, however, we describe an association between Bolivina pacifica, a foraminiferan with a calcareous test, and a rod-shaped microbe (bacterium or archaeon) that is directly associated with the <span class="hlt">pores</span> of the foraminiferan's test. In addition to these putative ectosymbionts, B. pacifica has previously undescribed cytoplasmic plasma membrane invaginations (PMIs). These adaptations (i.e. PMIs, ectobionts), along with the clustering of mitochondria under the <span class="hlt">pores</span> and at the cell periphery, suggest active exchange between the host and ectobiont. The B. pacifica specimens examined were collected from sediments overlain by oxygen-depleted bottom <span class="hlt">waters</span> (0.7 μM) of the Santa Barbara Basin (California, USA). An ultrastructural comparison between B. pacifica from the Santa Barbara Basin and a congener (Bolivina cf. B. lanceolata) collected from well-oxygenated sediments (Florida Keys) suggests that PMIs, ectobionts and peripherally distributed mitochondria are all factors that promote inhabitation of microxic environments by B. pacifica. The calcitic δ(13)C signatures of B. pacifica and of a co-occurring congener (B. argentea) that lacks ectobionts differ by > 1.5‰, raising the possibility that the presence of ectobionts can affect incorporation of paleoceanographic proxies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16083767','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16083767"><span>Dissolved organic matter in <span class="hlt">pore</span> <span class="hlt">water</span> of freshwater sediments: effects of separation procedure on quantity, quality and functionality.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Akkanen, Jarkko; Lyytikäinen, Merja; Tuikka, Anita; Kukkonen, Jussi V K</p> <p>2005-09-01</p> <p><span class="hlt">Pore</span> <span class="hlt">water</span> was separated either with or without <span class="hlt">water</span> extraction prior to centrifugation (7600 or 20,000 x g) in order to investigate the effects of separation procedure on the amount and properties of dissolved organic matter (DOM i.e. the material passing through a 0.45-microm filter) in three freshwater sediments. On the basis of solubility in alkaline, organic matter was concluded to compose of humic substances in two (S1 and S3) and of humin (S2) in one of the sediments. DOM in the samples was quantified by total organic carbon measurement. Specific UV-absorption (SUVA) and high performance size exclusion chromatography (HPSEC) analyses were used to characterize DOM. Sorption of pyrene was used as a measure for functionality of DOM. Both <span class="hlt">water</span> extraction and centrifugation speed were shown to affect the properties of DOM; however, the effects were sediment dependent. <span class="hlt">Water</span> extraction increased the amount of DOM separated from the two sediments that had humic character (S1 and S3). In most cases <span class="hlt">water</span> extraction increased SUVA and shifted the molecular size distribution of DOM towards larger sizes. The separation procedure had also an effect on the functionality of DOM. In <span class="hlt">water</span> extracted samples of S2 and S3 the sorption of pyrene was higher than in the corresponding samples separated without <span class="hlt">water</span> extraction, whereas in S1 similar effect was not found. Generally, centrifugation speed had smaller effects on the properties of DOM than <span class="hlt">water</span> extraction. The fact that the effects of separation procedure on DOM depend on the sediment characteristics complicates the comparison between samples and evaluation of functionality in field conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JMS...143...39B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JMS...143...39B"><span>Suspended <span class="hlt">marine</span> particulate proteins in coastal and oligotrophic <span class="hlt">waters</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bridoux, Maxime C.; Neibauer, Jaqui; Ingalls, Anitra E.; Nunn, Brook L.; Keil, Richard G.</p> <p>2015-03-01</p> <p>Metaproteomic analyses were performed on suspended sediments collected in one coastal environment (Washington margin, Pacific Ocean, n = 5) and two oligotrophic environments (Atlantic Ocean near BATS, n = 5, and Pacific Ocean near HOTS, n = 5). Using a database of 2.3 million <span class="hlt">marine</span> proteins developed using the NCBI database, 443 unique peptides were detected from which 363 unique proteins were identified. Samples from the euphotic zone contained on average 2-3x more identifiable proteins than deeper <span class="hlt">waters</span> (150-1500 m) and these proteins were predominately from photosynthetic organisms. Diatom peptides dominate the spectra of the Washington margin while peptides from cyanobacteria, such as Synechococcus sp. dominated the spectra of both oligotrophic sites. Despite differences in the exact proteins identified at each location, there is good agreement for protein function and cellular location. Proteins in surface <span class="hlt">waters</span> code for a variety of cellular functions including photosynthesis (24% of detected proteins), energy production (10%), membrane production (9%) and genetic coding and reading (9%), and are split 60-40 between membrane proteins and intracellular cytoplasmic proteins. Sargasso Sea surface <span class="hlt">waters</span> contain a suite of peptides consistent with proteins involved in circadian rhythms that promote both C and N fixation at night. At depth in the Sargasso Sea, both muscle-derived myosin protein and the muscle-hydrolyzing proteases deseasin MCP-01 and metalloprotease Mcp02 from γ-proteobacteria were observed. Deeper <span class="hlt">waters</span> contain peptides predominately sourced from γ-proteobacteria (37% of detected proteins) and α-proteobacteria (26%), although peptides from membrane and photosynthetic proteins attributable to phytoplankton were still observed (13%). Relative to surface values, detection frequencies for bacterial membrane proteins and extracellular enzymes rose from 9 to 16 and 2 to 4% respectively below the thermocline and the overall balance between</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3841840','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3841840"><span>High Resolution <span class="hlt">Marine</span> Magnetic Survey of Shallow <span class="hlt">Water</span> Littoral Area</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ginzburg, Boris; Cohen, Tsuriel Ram; Zafrir, Hovav; Alimi, Roger; Salomonski, Nizan; Sharvit, Jacob</p> <p>2007-01-01</p> <p>The purpose of this paper is to present a system developed for detection and accurate mapping of ferro-metallic objects buried below the seabed in shallow <span class="hlt">waters</span>. The system comprises a precise magnetic gradiometer and navigation subsystem, both installed on a non-magnetic catamaran towed by a low-magnetic interfering boat. In addition we present the results of a <span class="hlt">marine</span> survey of a near-shore area in the vicinity of Atlit, a town situated on the Mediterranean coast of Israel, about 15 km south of Haifa. The primary purpose of the survey was to search for a Harvard airplane that crashed into the sea in 1960. A magnetic map of the survey area (3.5 km2 on a 0.5 m grid) was created revealing the anomalies at sub-meter accuracy. For each investigated target location a corresponding ferro-metallic item was dug out, one of which turned to be very similar to a part of the crashed airplane. The accuracy of location was confirmed by matching the position of the actual dug artifacts with the magnetic map within a range of ± 1 m, in a <span class="hlt">water</span> depth of 9 m.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=226152&keyword=burkhard&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=90759676&CFTOKEN=99673896','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=226152&keyword=burkhard&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=90759676&CFTOKEN=99673896"><span>Comparing Sediment and <span class="hlt">Pore-water</span> Measurements as Predictors of PCB Uptake by Oligochaetes from Sediments</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>There is an increasing amount of chemical and biological evidence that using sediment concentrations and commonly applied Koc values frequently overpredicts interstitial <span class="hlt">water</span> concentrations of HOCs, and thereby overestimates uptake and/or effects of those chemicals on exposed or...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NIMPB.385....9S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NIMPB.385....9S"><span>Scattering of hydrogen, nitrogen and <span class="hlt">water</span> ions from micro <span class="hlt">pore</span> optic plates for application in spaceborne plasma instrumentation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stude, Joan; Wieser, Martin; Barabash, Stas</p> <p>2016-10-01</p> <p>Time-of-flight mass spectrometers for upcoming space missions into enhanced radiation environments need to be small, light weight and energy efficient. Time-of-flight systems using surface interactions as start-event generation can be smaller than foil-type instruments. Start surfaces for such applications need to provide narrow angular scattering, high ionization yields and high secondary electron emissions to be effective. We measured the angular scattering, energy distribution and positive ionization yield of micro <span class="hlt">pore</span> optics for incident hydrogen, nitrogen and <span class="hlt">water</span> ions at 2 keV. Positive ionization yields of 2% for H+ , 0.5% for N+ and 0.2% for H2O+ were detected.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/884716','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/884716"><span>Measurement and modeling of energetic-material mass transfer to soil-<span class="hlt">pore</span> <span class="hlt">water</span> - Project CP-1227 final technical report.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Stein, Joshua S.; Sallaberry, Cedric M.; Webb, Stephen Walter; Phelan, James M.; Hadgu, Teklu</p> <p>2006-05-01</p> <p>Military test and training ranges operate with live-fire engagements to provide realism important to the maintenance of key tactical skills. Ordnance detonations during these operations typically produce minute residues of parent explosive chemical compounds. Occasional low-order detonations also disperse solid-phase energetic material onto the surface soil. These detonation remnants are implicated in chemical contamination impacts to groundwater on a limited set of ranges where environmental characterization projects have occurred. Key questions arise regarding how these residues and the environmental conditions (e.g., weather and geostratigraphy) contribute to groundwater pollution. This final report documents the results of experimental and simulation model development for evaluating mass transfer processes from solid-phase energetics to soil-<span class="hlt">pore</span> <span class="hlt">water</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/921717','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/921717"><span>Measurement and modeling of energetic material mass transfer to soil <span class="hlt">pore</span> <span class="hlt">water</span> : Project CP-1227 : FY04 annual technical report.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Stein, Joshua S.; Webb, Stephen Walter</p> <p>2005-01-01</p> <p>Military test and training ranges operate with live fire engagements to provide realism important to the maintenance of key tactical skills. Ordnance detonations during these operations typically produce minute residues of parent explosive chemical compounds. Occasional low order detonations also disperse solid phase energetic material onto the surface soil. These detonation remnants are implicated in chemical contamination impacts to groundwater on a limited set of ranges where environmental characterization projects have occurred. Key questions arise regarding how these residues and the environmental conditions (e.g., weather and geostratigraphy) contribute to groundwater pollution impacts. This report documents interim results of a mass transfer model evaluating mass transfer processes from solid phase energetics to soil <span class="hlt">pore</span> <span class="hlt">water</span> based on experimental work obtained earlier in this project. This mass transfer numerical model has been incorporated into the porous media simulation code T2TNT. Next year, the energetic material mass transfer model will be developed further using additional experimental data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/1996/0459/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/1996/0459/report.pdf"><span>Determination of atrazine and its major degradation products in soil <span class="hlt">pore</span> <span class="hlt">water</span> by solid-phase extraction, chemical derivatization, and gas chromatography/mass spectrometry</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Carter, D.S.</p> <p>1996-01-01</p> <p>This report describes a method for the determination of atrazine, desethylatrazine, deisopropylatrazine, didealkylatrazine, and hydroxyatrazine from soil <span class="hlt">pore</span> <span class="hlt">waters</span> by use of solid-phase extractionfollowed by chemical derivatization and gas chromatography/mass spectrometry. The analytes are isolated from the <span class="hlt">pore-water</span> matrix byextraction onto a graphitized carbon-black cartridge. The cartridge is dried under vacuum, and adsorbed analytes are removed by elution with ethyl acetate followed by dichloromethane/methanol (7:3, volume/volume). <span class="hlt">Water</span> is removed from the ethyl acetate fraction on an anhydrous sodium sulfate column. The combined fractions are solvent exchanged into acetonitrile, evaporated by use of a nitrogen stream, and derivatized by use of N- methyl-N-(tert-butyldimethylsilyl)- trifluoroacetamide. The derivatized extracts are analyzed by capillary-column gaschromatography/electron-impact mass spectrometry in the scan mode. Estimated method detection limits range from 0.03 to 0.07 micrograms per liter. The mean recoveries of all analytes and surrogates determined at 0.74 to 0.82 micrograms per liter in reagent <span class="hlt">water</span> in soil <span class="hlt">pore</span> <span class="hlt">water</span> were 94 percent and 98 percent, respectively. The mean recoveries of all analytes and surrogates determined at 7.4 to 8.2 micrograms per liter in reagent <span class="hlt">water</span> and in soil <span class="hlt">pore</span> <span class="hlt">water</span> were 96 percent and 97 percent,respectively. Recoveries were 90 percent or higher, regardless of analyte concentration or matrix composition, for all compounds excepthydroxyatrazine, whose recoveries were slightly lower (77 percent) at the low concentration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014GML....34..241M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GML....34..241M"><span>Sequentially sampled gas hydrate <span class="hlt">water</span>, coupled with <span class="hlt">pore</span> <span class="hlt">water</span> and bottom <span class="hlt">water</span> isotopic and ionic signatures at the Kukuy mud volcano, Lake Baikal: ambiguous deep-rooted source of hydrate-forming <span class="hlt">water</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Minami, Hirotsugu; Hachikubo, Akihiro; Sakagami, Hirotoshi; Yamashita, Satoshi; Soramoto, Yusuke; Kotake, Tsuyoshi; Takahashi, Nobuo; Shoji, Hitoshi; Pogodaeva, Tatyana; Khlystov, Oleg; Khabuev, Andrey; Naudts, Lieven; De Batist, Marc</p> <p>2014-06-01</p> <p>The isotopic and ionic composition of pure gas hydrate (GH) <span class="hlt">water</span> was examined for GHs recovered in three gravity cores (165-193 cm length) from the Kukuy K-9 mud volcano (MV) in Lake Baikal. A massive GH sample from core St6GC4 (143-165 cm core depth interval) was dissociated progressively over 6 h in a closed glass chamber, and 11 sequentially collected fractions of dissociated GH <span class="hlt">water</span> analyzed. Their hydrogen and oxygen isotopic compositions, and the concentrations of Cl- and HCO3 - remained essentially constant over time, except that the fraction collected during the first 50 minutes deviated partly from this pattern. Fraction #1 had a substantially higher Cl- concentration, similar to that of <span class="hlt">pore</span> <span class="hlt">water</span> sampled immediately above (135-142 cm core depth) the main GH-bearing interval in that core. Like the subsequent fractions, however, the HCO3 - concentration was markedly lower than that of <span class="hlt">pore</span> <span class="hlt">water</span>. For the GH <span class="hlt">water</span> fractions #2 to #11, an essentially constant HCO3 -/Cl- ratio of 305 differed markedly from downcore <span class="hlt">pore</span> <span class="hlt">water</span> HCO3 -/Cl- ratios of 63-99. Evidently, contamination of the extracted GH <span class="hlt">water</span> by ambient <span class="hlt">pore</span> <span class="hlt">water</span> probably adhered to the massive GH sample was satisfactorily restricted to the initial phase of GH dissociation. The hydrogen and oxygen isotopic composition of hydrate-forming <span class="hlt">water</span> was estimated using the measured isotopic composition of extracted GH <span class="hlt">water</span> combined with known isotopic fractionation factors between GH and GH-forming <span class="hlt">water</span>. Estimated δD of -126 to -133‰ and δ18O of -15.7 to -16.7‰ differed partly from the corresponding signatures of ambient <span class="hlt">pore</span> <span class="hlt">water</span> (δD of -123‰, δ18O of -15.6‰) and of lake bottom <span class="hlt">water</span> (δD of -121‰, δ18O of -15.8‰) at the St6GC4 coring site, suggesting that the GH was not formed from those <span class="hlt">waters</span>. Observations of breccias in that core point to a possible deep-rooted <span class="hlt">water</span> source, consistent with published thermal measurements for the neighboring Kukuy K-2 MV. By contrast, the <span class="hlt">pore</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25130624','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25130624"><span>Biogeochemical environments of streambed-sediment <span class="hlt">pore</span> <span class="hlt">waters</span> with and without arsenic enrichment in a sedimentary rock terrain, New Jersey Piedmont, USA.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mumford, A C; Barringer, J L; Reilly, P A; Eberl, D D; Blum, A E; Young, L Y</p> <p>2015-02-01</p> <p>Release of arsenic (As) from sedimentary rocks has resulted in contamination of groundwater in aquifers of the New Jersey Piedmont Physiographic Province, USA; the contamination also may affect the quality of the region's streamwater to which groundwater discharges. Biogeochemical mechanisms involved in the release process were investigated in the streambeds of Six Mile Run and Pike Run, tributaries to the Millstone River in the Piedmont. At Six Mile Run, streambed <span class="hlt">pore</span> <span class="hlt">water</span> and shallow groundwater were low or depleted in oxygen, and contained As at concentrations greater than 20 μg/L. At Pike Run, oxidizing conditions were present in the streambed, and the As concentration in <span class="hlt">pore</span> <span class="hlt">water</span> was 2.1 μg/L. The 16S rRNA gene and the As(V) respiratory reductase gene, arrA, were amplified from DNA extracted from streambed <span class="hlt">pore</span> <span class="hlt">water</span> at both sites and analyzed, revealing that distinct bacterial communities that corresponded to the redox conditions were present at each site. Anaerobic enrichment cultures were inoculated with <span class="hlt">pore</span> <span class="hlt">water</span> from gaining reaches of the streams with acetate and As(V). As(V) was reduced by microbes to As(III) in enrichments with Six Mile Run <span class="hlt">pore</span> <span class="hlt">water</span> and groundwater, whereas no reduction occurred in enrichments with Pike Run <span class="hlt">pore</span> <span class="hlt">water</span>. Cloning and sequencing of the arrA gene indicated 8 unique operational taxonomic units (OTUs) at Six Mile Run and 11 unique OTUs at Pike Run, which may be representative of the arsenite oxidase gene arxA. Low-oxygen conditions at Six Mile Run have favored microbial As reduction and release, whereas release was inhibited by oxidizing conditions at Pike Run.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013BGD....1018241T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013BGD....1018241T"><span>Methane production correlates positively with methanogens, sulfate-reducing bacteria and <span class="hlt">pore</span> <span class="hlt">water</span> acetate at an estuarine brackish-marsh landscape scale</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tong, C.; She, C. X.; Jin, Y. F.; Yang, P.; Huang, J. F.</p> <p>2013-11-01</p> <p>Methane production is influenced by the abundance of methanogens and the availability of terminal substrates. Sulfate-reducing bacteria (SRB) also play an important role in the anaerobic decomposition of organic matter. However, the relationships between methane production and methanogen populations, <span class="hlt">pore</span> <span class="hlt">water</span> terminal substrates in estuarine brackish marshes are poorly characterized, and even to our knowledge, no published research has explored the relationship between methane production rate and abundance of SRB and <span class="hlt">pore</span> <span class="hlt">water</span> dimethyl sulfide (DMS) concentration. We investigated methane production rate, abundances of methanogens and SRB, concentrations of <span class="hlt">pore</span> <span class="hlt">water</span> terminal substrates and electron acceptors at a brackish marsh landscape dominated by Phragmites australis, Cyperus malaccensis and Spatina alterniflora marshes zones in the Min River estuary. The average rates of methane production at a soil depth of 30 cm in the three marsh zones were 0.142, 0.058 and 0.067 μg g-1 d-1, respectively. The abundance of both methanogens and SRB in the soil of the P. australis marsh with highest soil organic carbon content was higher than in the C. malaccensis and S. alterniflora marshes. The abundance of methanogens and SRB in the three soil layers was statistically indistinguishable. Mean <span class="hlt">pore</span> <span class="hlt">water</span> DMS concentrations at a soil depth of 30 cm under the S. alterniflora marsh were higher than those in the C. malaccensis and P. australis marshes. Methane production rate increased with the abundance of both methanogens and SRB across three marsh zones together at the landscape scale, and also increased with the concentration of <span class="hlt">pore</span> <span class="hlt">water</span> acetate, but did not correlate with concentrations of <span class="hlt">pore</span> <span class="hlt">water</span> DMS and dissolved CO2. Our results suggest that, provided that substrates are available in ample supply, methanogens can continue to produce methane regardless of whether SRB are prevalent in estuarine brackish marshes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70126405','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70126405"><span>Biogeochemical environments of streambed-sediment <span class="hlt">pore</span> <span class="hlt">waters</span> withand without arsenic enrichment in a sedimentary rock terrain, New Jersey Piedmont, USA</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Mumford, Adam C.; Barringer, Julia L.; Reilly, Pamela A.; Eberl, Dennis D.; Blum, Alex E.; Young, Lily Y.</p> <p>2015-01-01</p> <p>Release of arsenic (As) from sedimentary rocks has resulted in contamination of groundwater in aquifers of the New Jersey Piedmont Physiographic Province, USA; the contamination also may affect the quality of the region's streamwater to which groundwater discharges. Biogeochemical mechanisms involved in the release process were investigated in the streambeds of Six Mile Run and Pike Run, tributaries to the Millstone River in the Piedmont. At Six Mile Run, streambed <span class="hlt">pore</span> <span class="hlt">water</span> and shallow groundwater were low or depleted in oxygen, and contained As at concentrations greater than 20μg/L. At Pike Run, oxidizing conditions were present in the streambed, and the As concentration in <span class="hlt">pore</span> <span class="hlt">water</span> was 2.1μg/L. The 16S rRNA gene and the As(V) respiratory reductase gene, arrA, were amplified from DNA extracted from streambed <span class="hlt">pore</span> <span class="hlt">water</span> at both sites and analyzed, revealing that distinct bacterial communities that corresponded to the redox conditions were present at each site. Anaerobic enrichment cultures were inoculated with <span class="hlt">pore</span> <span class="hlt">water</span> from gaining reaches of the streams with acetate and As(V). As(V) was reduced by microbes to As(III) in enrichments with Six Mile Run <span class="hlt">pore</span> <span class="hlt">water</span> and groundwater, whereas no reduction occurred in enrichments with Pike Run <span class="hlt">pore</span> <span class="hlt">water</span>. Cloning and sequencing of the arrA gene indicated 8 unique operational taxonomic units (OTUs) at Six Mile Run and 11 unique OTUs at Pike Run, which may be representative of the arsenite oxidase gene arxA. Low-oxygen conditions at Six Mile Run have favored microbial As reduction and release, whereas release was inhibited by oxidizing conditions at Pike Run.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA630976','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA630976"><span>Airborne, In Situ and Laboratory Measurements of the Optical and Photochemical Properties of Surface <span class="hlt">Marine</span> <span class="hlt">Waters</span></span></a></p> <p><a target="_blank" href="https://publicaccess.dtic.mil/psm/api/service/search/search">DTIC Science & Technology</a></p> <p></p> <p>2016-06-07</p> <p>Airborne, In Situ And Laboratory Measurements Of The Optical And Photochemical Properties Of Surface <span class="hlt">Marine</span> <span class="hlt">Waters</span> Neil V. Blough Department of...matter (CDOM) in <span class="hlt">marine</span> and estuarine <span class="hlt">waters</span> , 2) to determine the impact of CDOM on the aquatic light field and remotely-sensed optical signals, 3) to...October 1999 was performed to examine the optical and photochemical properties of <span class="hlt">waters</span> in the Middle Atlantic Bight and in the Delaware and Chesapeake</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/951961','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/951961"><span>Modeling the diffusion of Na+ in compacted <span class="hlt">water</span>-saturated Na-bentonite as a function of <span class="hlt">pore</span> <span class="hlt">water</span> ionic strength</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bourg, I.C.; Sposito, G.; Bourg, A.C.M.</p> <p>2008-08-15</p> <p>Assessments of bentonite barrier performance in waste management scenarios require an accurate description of the diffusion of <span class="hlt">water</span> and solutes through the barrier. A two-compartment macropore/nanopore model (on which smectite interlayer nanopores are treated as a distinct compartment of the overall <span class="hlt">pore</span> space) was applied to describe the diffusion of {sup 22}Na{sup +} in compacted, <span class="hlt">water</span>-saturated Na-bentonites and then compared with the well-known surface diffusion model. The two-compartment model successfully predicted the observed weak ionic strength dependence of the apparent diffusion coefficient (D{sub a}) of Na{sup +}, whereas the surface diffusion model did not, thus confirming previous research indicating the strong influence of interlayer nanopores on the properties of smectite clay barriers. Since bentonite mechanical properties and <span class="hlt">pore</span> <span class="hlt">water</span> chemistry have been described successfully with two-compartment models, the results in the present study represent an important contribution toward the construction of a comprehensive two-compartment model of compacted bentonite barriers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4339505','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4339505"><span>Erythritol predicted to inhibit permeation of <span class="hlt">water</span> and solutes through the conducting <span class="hlt">pore</span> of P. falciparum aquaporin</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Chen, Liao Y.</p> <p>2015-01-01</p> <p>Plasmodium falciparum aquaporin (PfAQP) is a multifunctional channel protein in the plasma membrane of the malarial parasite that causes the most severe form of malaria infecting more than a million people a year. This channel protein facilitates transport of <span class="hlt">water</span> and several solutes across the cell membrane. In order to better elucidate the fundamental interactions between PfAQP and its permeants and among the permeants, I conducted over three microseconds in silico experiments of atomistic models of the PfAQP-membrane system to obtain the free-energy profiles of five permeants (erythritol, <span class="hlt">water</span>, glycerol, urea, and ammonia) throughout the amphipathic conducting <span class="hlt">pore</span> of PfAQP. The profiles are analyzed in light of and shown to be consistent with the existent in vitro data. The binding affinities are computed using the free-energy profiles and the permeant fluctuations inside the channel. On this basis, it is predicted that erythritol, a permeant of PfAQP itself having a deep ditch in its permeation passageway, inhibits PfAQP’s functions of transporting <span class="hlt">water</span> and other solutes with an IC50 in the range of high nanomolars. This leads to the possibility that erythritol, a sweetener generally considered safe, may inhibit or kill the malarial parasite in vivo without causing undesired side effects. Experimental studies are hereby called for to directly test this theoretical prediction of erythritol strongly inhibiting PfAQP in vitro and possibly inhibiting P. falciparum in vivo. PMID:25637890</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25318392','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25318392"><span>Derivation of a <span class="hlt">water</span> quality guideline for aluminium in <span class="hlt">marine</span> <span class="hlt">waters</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Golding, Lisa A; Angel, Brad M; Batley, Graeme E; Apte, Simon C; Krassoi, Rick; Doyle, Chris J</p> <p>2015-01-01</p> <p>Metal risk assessment of industrialized harbors and coastal <span class="hlt">marine</span> <span class="hlt">waters</span> requires the application of robust <span class="hlt">water</span> quality guidelines to determine the likelihood of biological impacts. Currently there is no such guideline available for aluminium in <span class="hlt">marine</span> <span class="hlt">waters</span>. A <span class="hlt">water</span> quality guideline of 24 µg total Al/L has been developed for aluminium in <span class="hlt">marine</span> <span class="hlt">waters</span> based on chronic 10% inhibition or effect concentrations (IC10 or EC10) and no-observed-effect concentrations (NOECs) from 11 species (2 literature values and 9 species tested including temperate and tropical species) representing 6 taxonomic groups. The 3 most sensitive species tested were a diatom Ceratoneis closterium (formerly Nitzschia closterium; IC10 = 18 µg Al/L, 72-h growth rate inhibition) < mussel Mytilus edulis plannulatus (EC10 = 250 µg Al/L, 72-h embryo development) < oyster Saccostrea echinata (EC10 = 410 µg Al/L, 48-h embryo development). Toxicity to these species was the result of the dissolved aluminium forms of aluminate (Al(OH4 (-) ) and aluminium hydroxide (Al(OH)3 (0) ) although both dissolved, and particulate aluminium contributed to toxicity in the diatom Minutocellus polymorphus and green alga Dunaliella tertiolecta. In contrast, aluminium toxicity to the green flagellate alga Tetraselmis sp. was the result of particulate aluminium only. Four species, a brown macroalga (Hormosira banksii), sea urchin embryo (Heliocidaris tuberculata), and 2 juvenile fish species (Lates calcarifer and Acanthochromis polyacanthus), were not adversely affected at the highest test concentration used.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2007/5154/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2007/5154/"><span>Evaluation of <span class="hlt">pore-water</span> samplers at a drainage ditch, Installation Restoration Site 4, Naval Air Station Corpus Christi, Corpus Christi, Texas, 2005–06</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Vroblesky, Don A.; Casey, Clifton C.</p> <p>2007-01-01</p> <p>The U.S. Geological Survey, in cooperation with the Naval Facilities Engineering Command Southeast, used innovative sampling methods to investigate ground-<span class="hlt">water</span> contamination by chlorobenzenes beneath a drainage ditch on the southwestern side of Installation Restoration Site 4, Naval Air Station Corpus Christi, Corpus Christi, Texas, during 2005-06. The drainage ditch, which is a potential receptor for ground-<span class="hlt">water</span> contaminants from Installation Restoration Site 4, intermittently discharges <span class="hlt">water</span> to Corpus Christi Bay. This report evaluates a new type of <span class="hlt">pore-water</span> sampler developed for this investigation to examine the subsurface contamination beneath the drainage ditch. The new type of <span class="hlt">pore-water</span> sampler appears to be an effective approach for long-term monitoring of ground <span class="hlt">water</span> in the sand and organic-rich mud beneath the drainage ditch.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.H41L..08O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.H41L..08O"><span><span class="hlt">Pore</span>-Scale Effects of Soil Structure And Microbial EPS Production On Soil <span class="hlt">Water</span> Retention</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Orner, E.; Anderson, E.; Rubinstein, R. L.; Chau, J. F.; Shor, L. M.; Gage, D. J.</p> <p>2013-12-01</p> <p>Climate-induced changes to the hydrological cycle will increase the frequency of extreme weather events including powerful storms and prolonged droughts. Moving forward, one of the major factors limiting primary productivity in terrestrial ecosystems will be sub-optimal soil moisture. We focus here on the ability of soils to retain moisture under drying conditions. A soil's ability to retain moisture is influenced by many factors including its texture, its structure, and the activities of soil microbes. In soil microcosms, the addition of small amounts of microbially-produced extracellular polymeric substances (EPS) can dramatically shift moisture retention curves. The objective of this research is to better understand how soil structure and EPS may act together to retain moisture in unsaturated soils. Replicate micromodels with exactly-conserved 2-D physical geometry were initially filled with aqueous suspensions of one of two types of bacteria: one mutant was ultra- muccoid and the other was non-muccoid. Replicate micromodels were held at a fixed, external, relative humidity, and the position of the air-<span class="hlt">water</span> interface was imaged over time as <span class="hlt">water</span> evaporates. There was no forced convection of air or <span class="hlt">water</span> inside the micromodels: drying was achieved by <span class="hlt">water</span> evaporation and diffusion alone. We used a fully automated, inverted microscope to image replicate drying lanes each with dimensions of 1 mm x 10 mm. A complete set of images was collected every 30 minutes for 30 hours. The results show devices loaded with the highly muccoid strain remained >40% hydrated for 13 h, while devices loaded with the non-muccoid remained >40% hydrated for only 6 h, and were completely dry by 13 h. Current work is comparing interfacial <span class="hlt">water</span> fluxes in structured and unstructured settings, and is attempting to model the synergistic effects of soil structure and EPS content on moisture retention in real soils. This research may allow more accurate description of naturally</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DFD.G9005Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DFD.G9005Z"><span>Flow enhancement of <span class="hlt">water</span> flow through silica slit <span class="hlt">pores</span> with graphene-coated walls</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zambrano, Harvey; Wagemann, Enrique; Oyarzua, Elton; Walther, J. H.</p> <p>2015-11-01</p> <p>Nanofluidic devices such as Lab-On-a-Chip often are designed to transport <span class="hlt">water</span> solutions through hydrophilic nano-conduits. In these systems with narrow confinement, the viscous forces dominate the flow and as a result, the hydrodynamic friction drag is very high. Moreover, the drag and the amount of energy required for pumping a fluid are directly related. Therefore, it is desirable to explore drag reduction strategies in nanoconfined flows. Liquids are known to slip past non-wetting surfaces. Graphene is a single-atom-thick sheet of carbon atoms arranged in a hexagonal honeycomb lattice, which features a unparalleled combination of high specific surface area, chemical stability, mechanical strength and flexibility. Recently, the wettability of <span class="hlt">water</span> droplets on multilayer graphene sheets deposited on a silica substrate has been investigated. In this study, we investigate the role of graphene coatings to induce flow enhancement in silica channels. We conduct molecular dynamics simulations of pressurized <span class="hlt">water</span> flow inside silica channels with and without graphene layers covering the walls. In particular, we compute density and velocity profiles, flow enhancement and slip lengths to understand the drag reduction capabilities of multilayer graphene coatings. We aknowledge partial support from Fondecyt project 11130559.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5334613','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5334613"><span>Recent Trends in <span class="hlt">Marine</span> Phycotoxins from Australian Coastal <span class="hlt">Waters</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ajani, Penelope; Harwood, D. Tim; Murray, Shauna A.</p> <p>2017-01-01</p> <p>Phycotoxins, which are produced by harmful microalgae and bioaccumulate in the <span class="hlt">marine</span> food web, are of growing concern for Australia. These harmful algae pose a threat to ecosystem and human health, as well as constraining the progress of aquaculture, one of the fastest growing food sectors in the world. With better monitoring, advanced analytical skills and an increase in microalgal expertise, many phycotoxins have been identified in Australian coastal <span class="hlt">waters</span> in recent years. The most concerning of these toxins are ciguatoxin, paralytic shellfish toxins, okadaic acid and domoic acid, with palytoxin and karlotoxin increasing in significance. The potential for tetrodotoxin, maitotoxin and palytoxin to contaminate seafood is also of concern, warranting future investigation. The largest and most significant toxic bloom in Tasmania in 2012 resulted in an estimated total economic loss of ~AUD$23M, indicating that there is an imperative to improve toxin and organism detection methods, clarify the toxin profiles of species of phytoplankton and carry out both intra- and inter-species toxicity comparisons. Future work also includes the application of rapid, real-time molecular assays for the detection of harmful species and toxin genes. This information, in conjunction with a better understanding of the life histories and ecology of harmful bloom species, may lead to more appropriate management of environmental, health and economic resources. PMID:28208796</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26287831','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26287831"><span>Abatement vs. treatment for efficient diffuse source <span class="hlt">water</span> pollution management in terrestrial-<span class="hlt">marine</span> systems.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Roebeling, P C; Cunha, M C; Arroja, L; van Grieken, M E</p> <p>2015-01-01</p> <p><span class="hlt">Marine</span> ecosystems are affected by <span class="hlt">water</span> pollution originating from coastal catchments. The delivery of <span class="hlt">water</span> pollutants can be reduced through <span class="hlt">water</span> pollution abatement as well as <span class="hlt">water</span> pollution treatment. Hence, sustainable economic development of coastal regions requires balancing of the marginal costs from <span class="hlt">water</span> pollution abatement and/or treatment and the associated marginal benefits from <span class="hlt">marine</span> resource appreciation. <span class="hlt">Water</span> pollution delivery reduction costs are, however, not equal across abatement and treatment options. In this paper, an optimal control approach is developed and applied to explore welfare maximizing rates of <span class="hlt">water</span> pollution abatement and/or treatment for efficient diffuse source <span class="hlt">water</span> pollution management in terrestrial-<span class="hlt">marine</span> systems. For the case of diffuse source dissolved inorganic nitrogen <span class="hlt">water</span> pollution in the Tully-Murray region, Queensland, Australia, (agricultural) <span class="hlt">water</span> pollution abatement cost, (wetland) <span class="hlt">water</span> pollution treatment cost and <span class="hlt">marine</span> benefit functions are determined to explore welfare maximizing rates of <span class="hlt">water</span> pollution abatement and/or treatment. Considering partial (wetland) treatment costs and positive <span class="hlt">water</span> quality improvement benefits, results show that welfare gains can be obtained, primarily, through diffuse source <span class="hlt">water</span> pollution abatement (improved agricultural management practices) and, to a minor extent, through diffuse source <span class="hlt">water</span> pollution treatment (wetland restoration).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2011-05-24/pdf/2011-12815.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2011-05-24/pdf/2011-12815.pdf"><span>76 FR 30023 - Pamlico Sound and Adjacent <span class="hlt">Waters</span>, NC; Danger Zones for <span class="hlt">Marine</span> Corps Operations</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2011-05-24</p> <p>... Subjects in 33 CFR Part 334 Danger zones, <span class="hlt">Marine</span> safety, Navigation (<span class="hlt">water</span>), Restricted areas, Waterways... current military training mission requires enhanced public safety and protection of vessels that operate.... Establishment of this additional danger zone will allow the <span class="hlt">Marine</span> Corps to minimize the public safety...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007WRR....43.4410G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007WRR....43.4410G"><span>Stable <span class="hlt">water</span> isotopes in <span class="hlt">pore</span> <span class="hlt">water</span> of Jurassic argillaceous rocks as tracers for solute transport over large spatial and temporal scales</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gimmi, T.; Waber, H. N.; Gautschi, A.; Rübel, A.</p> <p>2007-04-01</p> <p>In order to characterize the large-scale transport properties of the Opalinus Clay formation, the <span class="hlt">pore</span> <span class="hlt">water</span> isotope composition (δ18O and δ2H) was determined on samples from the deep borehole Benken (northeastern Switzerland) across Jurassic argillaceous rocks. The sequence of claystones and marls, delimited by two aquifers, is located at depth from about 400 to 700 m and exhibits very low hydraulic conductivities (below 10-13 m s-1). The isotope data of the <span class="hlt">pore</span> <span class="hlt">water</span> were obtained from core samples by diffusive vapor equilibration, vacuum distillation, and squeezing. Compared with the other methods, vacuum distillation led to too low values. To evaluate the large-scale transport properties of the formation, we performed a series of advective-dispersive model calculations and compared them with the experimental data. In accordance with the hydrogeological history, we varied initial and boundary conditions as well as model parameters. The main results can be summarized as follows: (1) Molecular diffusion to the underlying aquifer can explain the general features of the isotope profiles, (2) no signatures of advective flow could be detected, (3) the evolution time is of the order of 0.5-1 Ma (relying on laboratory diffusion coefficients) with a possible range of about 0.2-2 Ma, which is geologically plausible, and (4) parameters measured on small scales (centimeters or meters and months) are also plausible at the formation scale (tens of meters and millions of years) for the sediments investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApSS..387.1080L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApSS..387.1080L"><span>Selective surface adsorption and <span class="hlt">pore</span> trapping for ethanol-<span class="hlt">water</span> mixtures near single-layer polyporous graphynes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Fang; Yang, Jie; Xu, Zhijun; Yang, Xiaoning</p> <p>2016-11-01</p> <p>The interfacial behavior of ethanol-<span class="hlt">water</span> mixtures with various concentrations near single-layer polyporous γ-graphyne (Graphyne-n, n = 3,4,5) surfaces were investigated using molecular dynamics simulation. Comprehensive energetic analysis and structure properties, including density profiles, radial distribution functions, orientation distributions, and surface two-dimensional densities, have been simulated to quantify the surface-induced effect. Our simulation results illustrate micro-phase demixing phenomenon with ethanol molecules preferential adsorbing on the graphyne surfaces. This surface-induced demixing behavior is enhanced as the <span class="hlt">pore</span> area decreases for the γ-graphynes, that is, G-3 surface induces the strongest demixing of ethanol-<span class="hlt">water</span> mixture. Meanwhile, when in contacting with the graphyne-4 and graphyne-5 surfaces, ethanol molecules from the mixture are able to predominately occupy the nanopores of graphynes, and display selective ethanol penetration through single-layer graphynes. This unique interface behavior could be attributed to the enhanced hydrophobic interaction between amphiphilic ethanol molecules and graphyne carbon surfaces.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007BGD.....4.3701V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007BGD.....4.3701V"><span>Soil atmosphere exchange of Carbonyl Sulfide (COS) regulated by diffusivity depending on <span class="hlt">water</span>-filled <span class="hlt">pore</span> space</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van Diest, H.; Kesselmeier, J.</p> <p>2007-10-01</p> <p>The exchange of carbonyl sulfide (COS) between soil and the atmosphere was investigated for three arable soils from Germany, China and Finland and one forest soil from Siberia for parameterization in the relation to ambient carbonyl sulfide (COS) concentration, soil <span class="hlt">water</span> content (WC) and air temperature. All investigated soils acted as significant sinks for COS. A clear and distinct uptake optimum was found for the German, Chinese, Finnish and Siberian soils at 11.5%, 9%, 11.5%, and 9% soil WC, respectively, indicating that the soil WC acts as an important biological and physical parameter for characterizing the exchange of COS between soils and the atmosphere. Different optima of deposition velocities (Vd) as observed for the Chinese, Finnish and Siberian boreal soil types in relation to their soil WC, aligned at 19% in relation to the <span class="hlt">water</span>-filled <span class="hlt">pore</span> space (WFPS), indicating the dominating role of gas diffusion. This interpretation was supported by the linear correlation between Vd and bulk density. We suggest that the uptake of COS depends on the diffusivity dominated by WFPS, a parameter depending on soil WC, soil structure and porosity of the soil.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008BGeo....5..475V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008BGeo....5..475V"><span>Soil atmosphere exchange of carbonyl sulfide (COS) regulated by diffusivity depending on <span class="hlt">water</span>-filled <span class="hlt">pore</span> space</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van Diest, H.; Kesselmeier, J.</p> <p>2008-04-01</p> <p>The exchange of carbonyl sulfide (COS) between soil and the atmosphere was investigated for three arable soils from Germany, China and Finland and one forest soil from Siberia for parameterization in the relation to ambient carbonyl sulfide (COS) concentration, soil <span class="hlt">water</span> content (WC) and air temperature. All investigated soils acted as sinks for COS. A clear and distinct uptake optimum was found for the German, Chinese, Finnish and Siberian soils at 11.5%, 9%, 11.5%, and 9% soil WC, respectively, indicating that the soil WC acts as an important biological and physical parameter for characterizing the exchange of COS between soils and the atmosphere. Different optima of deposition velocities (Vd) as observed for the Chinese, Finnish and Siberian boreal soil types in relation to their soil WC, aligned at 19% in relation to the <span class="hlt">water</span>-filled <span class="hlt">pore</span> space (WFPS), indicating the dominating role of gas diffusion. This interpretation was supported by the linear correlation between Vd and bulk density. We suggest that the uptake of COS depends on the diffusivity dominated by WFPS, a parameter depending on soil WC, soil structure and porosity of the soil.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/808621','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/808621"><span>Measurement and Modeling of Energetic Material Mass Transfer to Soil <span class="hlt">Pore</span> <span class="hlt">Water</span> - Project CP-1227 Annual Technical Report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>PHELAN, JAMES M.; WEBB, STEPHEN W.; ROMERO, JOSEPH V.; BARNETT, JAMES L.; GRIFFIN, FAWN A.</p> <p>2003-01-01</p> <p>Military test and training ranges operate with live fire engagements to provide realism important to the maintenance of key tactical skills. Ordnance detonations during these operations typically produce minute residues of parent explosive chemical compounds. Occasional low order detonations also disperse solid phase energetic material onto the surface soil. These detonation remnants are implicated in chemical contamination impacts to groundwater on a limited set of ranges where environmental characterization projects have occurred. Key questions arise regarding how these residues and the environmental conditions (e.g. weather and geostratigraphy) contribute to groundwater pollution impacts. This report documents interim results of experimental work evaluating mass transfer processes from solid phase energetics to soil <span class="hlt">pore</span> <span class="hlt">water</span>. The experimental work is used as a basis to formulate a mass transfer numerical model, which has been incorporated into the porous media simulation code T2TNT. Experimental work to date with Composition B explosive has shown that column tests typically produce effluents near the temperature dependent solubility limits for RDX and TNT. The influence of <span class="hlt">water</span> flow rate, temperature, porous media saturation and mass loading is documented. The mass transfer model formulation uses a mass transfer coefficient and surface area function and shows good agreement with the experimental data. Continued experimental work is necessary to evaluate solid phase particle size and 2-dimensional effects, and actual low order detonation debris. Simulation model improvements will continue leading to a capability to complete screening assessments of the impacts of military range operations on groundwater quality.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22676368','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22676368"><span>Experimental study of crossover from capillary to viscous fingering for supercritical CO2-<span class="hlt">water</span> displacement in a homogeneous <span class="hlt">pore</span> network.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Ying; Zhang, Changyong; Wei, Ning; Oostrom, Mart; Wietsma, Thomas W; Li, Xiaochun; Bonneville, Alain</p> <p>2013-01-02</p> <p>Carbon sequestration in saline aquifers involves displacing brine from the <span class="hlt">pore</span> space by supercritical CO(2) (scCO(2)). The displacement process is considered unstable due to the unfavorable viscosity ratio between the invading scCO(2) and the resident brine. The mechanisms that affect scCO(2)-<span class="hlt">water</span> displacement under reservoir conditions (41 °C, 9 MPa) were investigated in a homogeneous micromodel. A large range of injection rates, expressed as the dimensionless capillary number (Ca), was studied in two sets of experiments: discontinuous-rate injection, where the micromodel was saturated with <span class="hlt">water</span> before each injection rate was imposed, and continuous-rate injection, where the rate was increased after quasi-steady conditions were reached for a certain rate. For the discontinuous-rate experiments, capillary fingering and viscous fingering are the dominant mechanisms for low (logCa ≤ -6.61) and high injection rates (logCa ≥ -5.21), respectively. Crossover from capillary to viscous fingering was observed for logCa = -5.91 to -5.21, resulting in a large decrease in scCO(2) saturation. The discontinuous-rate experimental results confirmed the decrease in nonwetting fluid saturation during crossover from capillary to viscous fingering predicted by numerical simulations by Lenormand et al. (J. Fluid Mech.1988, 189, 165-187). Capillary fingering was the dominant mechanism for all injection rates in the continuous-rate experiment, resulting in monotonic increase in scCO(2) saturation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1252733','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1252733"><span>Simulations of the infrared, Raman, and 2D-IR photon echo spectra of <span class="hlt">water</span> in nanoscale silica <span class="hlt">pores</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Burris, Paul C.; Laage, Damien; Thompson, Ward H.</p> <p>2016-05-20</p> <p>Vibrational spectroscopy is frequently used to characterize nanoconfined liquids and probe the effect of the confining framework on the liquid structure and dynamics relative to the corresponding bulk fluid. However, it is still unclear what molecular-level information can be obtained from such measurements. In this Paper, we address this question by using molecular dynamics (MD) simulations to reproduce the linear infrared (IR), Raman, and two-dimensional IR (2D-IR) photon echo spectra for <span class="hlt">water</span> confined within hydrophilic (hydroxyl-terminated) silica mesopores. To simplify the spectra the OH stretching region of isotopically dilute HOD in D<sub>2</sub>O is considered. An empirical mapping approach is used to obtain the OH vibrational frequencies, transition dipoles, and transition polarizabilities from the MD simulations. The simulated linear IR and Raman spectra are in good general agreement with measured spectra of <span class="hlt">water</span> in mesoporous silica reported in the literature. The key effect of confinement on the <span class="hlt">water</span> spectrum is a vibrational blueshift for OH groups that are closest to the <span class="hlt">pore</span> interface. The blueshift can be attributed to the weaker hydrogen bonds (H-bonds) formed between the OH groups and silica oxygen acceptors. Non-Condon effects greatly diminish the contribution of these OH moieties to the linear IR spectrum, but these weaker H-bonds are readily apparent in the Raman spectrum. The 2D-IR spectra have not yet been measured and thus the present results represent a prediction. Lastly, the simulated spectra indicate that it should be possible to probe the slower spectral diffusion of confined <span class="hlt">water</span> compared to the bulk liquid by analysis of the 2D-IR spectra.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27208967','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27208967"><span>Simulations of the infrared, Raman, and 2D-IR photon echo spectra of <span class="hlt">water</span> in nanoscale silica <span class="hlt">pores</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Burris, Paul C; Laage, Damien; Thompson, Ward H</p> <p>2016-05-21</p> <p>Vibrational spectroscopy is frequently used to characterize nanoconfined liquids and probe the effect of the confining framework on the liquid structure and dynamics relative to the corresponding bulk fluid. However, it is still unclear what molecular-level information can be obtained from such measurements. In this paper, we address this question by using molecular dynamics (MD) simulations to reproduce the linear infrared (IR), Raman, and two-dimensional IR (2D-IR) photon echo spectra for <span class="hlt">water</span> confined within hydrophilic (hydroxyl-terminated) silica mesopores. To simplify the spectra the OH stretching region of isotopically dilute HOD in D2O is considered. An empirical mapping approach is used to obtain the OH vibrational frequencies, transition dipoles, and transition polarizabilities from the MD simulations. The simulated linear IR and Raman spectra are in good general agreement with measured spectra of <span class="hlt">water</span> in mesoporous silica reported in the literature. The key effect of confinement on the <span class="hlt">water</span> spectrum is a vibrational blueshift for OH groups that are closest to the <span class="hlt">pore</span> interface. The blueshift can be attributed to the weaker hydrogen bonds (H-bonds) formed between the OH groups and silica oxygen acceptors. Non-Condon effects greatly diminish the contribution of these OH moieties to the linear IR spectrum, but these weaker H-bonds are readily apparent in the Raman spectrum. The 2D-IR spectra have not yet been measured and thus the present results represent a prediction. The simulated spectra indicates that it should be possible to probe the slower spectral diffusion of confined <span class="hlt">water</span> compared to the bulk liquid by analysis of the 2D-IR spectra.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1252733-simulations-infrared-raman-ir-photon-echo-spectra-water-nanoscale-silica-pores','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1252733-simulations-infrared-raman-ir-photon-echo-spectra-water-nanoscale-silica-pores"><span>Simulations of the infrared, Raman, and 2D-IR photon echo spectra of <span class="hlt">water</span> in nanoscale silica <span class="hlt">pores</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Burris, Paul C.; Laage, Damien; Thompson, Ward H.</p> <p>2016-05-20</p> <p>Vibrational spectroscopy is frequently used to characterize nanoconfined liquids and probe the effect of the confining framework on the liquid structure and dynamics relative to the corresponding bulk fluid. However, it is still unclear what molecular-level information can be obtained from such measurements. In this Paper, we address this question by using molecular dynamics (MD) simulations to reproduce the linear infrared (IR), Raman, and two-dimensional IR (2D-IR) photon echo spectra for <span class="hlt">water</span> confined within hydrophilic (hydroxyl-terminated) silica mesopores. To simplify the spectra the OH stretching region of isotopically dilute HOD in D2O is considered. An empirical mapping approach is usedmore » to obtain the OH vibrational frequencies, transition dipoles, and transition polarizabilities from the MD simulations. The simulated linear IR and Raman spectra are in good general agreement with measured spectra of <span class="hlt">water</span> in mesoporous silica reported in the literature. The key effect of confinement on the <span class="hlt">water</span> spectrum is a vibrational blueshift for OH groups that are closest to the <span class="hlt">pore</span> interface. The blueshift can be attributed to the weaker hydrogen bonds (H-bonds) formed between the OH groups and silica oxygen acceptors. Non-Condon effects greatly diminish the contribution of these OH moieties to the linear IR spectrum, but these weaker H-bonds are readily apparent in the Raman spectrum. The 2D-IR spectra have not yet been measured and thus the present results represent a prediction. Lastly, the simulated spectra indicate that it should be possible to probe the slower spectral diffusion of confined <span class="hlt">water</span> compared to the bulk liquid by analysis of the 2D-IR spectra.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JMS....85...30H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JMS....85...30H"><span>Seasonal variability of hydrographical properties of the Syrian <span class="hlt">marine</span> <span class="hlt">water</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hussein, Mohammad; Courp, Thierry; Ibrahim, Amir; Benkhelil, Jean</p> <p>2011-03-01</p> <p>The hydrographical properties of the Syrian <span class="hlt">marine</span> <span class="hlt">water</span> are described on the basis of three cruises performed during December 2006, March 2009 and October 2009. In all cruises a Conductivity-Temperature-Depth (CTD) instrument equipped with a fluorometer and oxygen sensor was used for casts that extended to a maximum depth of 480 m. The hydrographic data reveal the presence of Levantine Surface <span class="hlt">Water</span> (LSW) and Atlantic <span class="hlt">Water</span> (AW) within the upper 90 m layer, Levantine Intermediate <span class="hlt">Water</span> (LIW) between 90 and 250 m, and Deep <span class="hlt">Water</span> (DW) further below. Stratification was clearer in October and December compared to March. Cyclonic and anticyclonic eddies were observed during the three cruises at different locations situated along the Syrian coast. The flow structure along the Syrian coast is controlled by the shape of the coastline and the bottom topography of the continental shelf. From March 2009 to October 2009 a dynamic height rise (within 6 months) of about 3.7-9.8 cm reflected the seasonal cycle of sea level due mainly to thermosteric expansion of the <span class="hlt">water</span> column. This gave a rise rate in the range of 0.6-1.7 cm month - 1 . Dissolved oxygen was higher in March 2009 (214 ± 4.8 μM) than in December 2006 (202 ± 11.5 μM) or in October 2009 (188 ± 18.9 μM). During March 2009 the <span class="hlt">water</span> column oxygen distribution was homogeneous. In December 2006 the oxygen distribution was homogeneous in the upper 125 m where LSW was present and subsequently decreased in concentration due to bacterial oxidation of detritus. However, a shallow oxygen maximum (oversaturated) was present at 50-80 m depth during October 2009. Oversaturation was attributed mainly to the biological and physical processes of rapid capping and trapping of oxygen in the AW mass. Chlorophyll- a concentration varied substantially depending on depth and season, having values of 0.05 ± 0.01 mg m - 3 during December 2006, 0.08 ± 0.01 mg m - 3 during March 2009 and 0.06 ± 0.01 mg m - 3 during October 2009</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25602329','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25602329"><span>Microbial metabolism alters <span class="hlt">pore</span> <span class="hlt">water</span> chemistry and increases consolidation of oil sands tailings.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Arkell, Nicholas; Kuznetsov, Petr; Kuznetsova, Alsu; Foght, Julia M; Siddique, Tariq</p> <p>2015-01-01</p> <p>Tailings produced during bitumen extraction from surface-mined oil sands ores (tar sands) comprise an aqueous suspension of clay particles that remain dispersed for decades in tailings ponds. Slow consolidation of the clays hinders <span class="hlt">water</span> recovery for reuse and retards volume reduction, thereby increasing the environmental footprint of tailings ponds. We investigated mechanisms of tailings consolidation and revealed that indigenous anaerobic microorganisms altered porewater chemistry by producing CO and CH during metabolism of acetate added as a labile carbon amendment. Entrapped biogenic CO decreased tailings pH, thereby increasing calcium (Ca) and magnesium (Mg) cations and bicarbonate (HCO) concentrations in the porewater through dissolution of carbonate minerals. Soluble ions increased the porewater ionic strength, which, with higher exchangeable Ca and Mg, decreased the diffuse double layer of clays and increased consolidation of tailings compared with unamended tailings in which little microbial activity was observed. These results are relevant to effective tailings pond management strategies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17674819','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17674819"><span>Review of fundamentals and specific aspects of oxidation technologies in <span class="hlt">marine</span> <span class="hlt">waters</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kornmueller, A</p> <p>2007-01-01</p> <p>This review is based on the existing literature and on our experiences in the application of different oxidation processes in brackish <span class="hlt">water</span> and seawater. The oxidation reactions of advanced oxidation processes (AOPs) and the formation of disinfection byproducts (DBPs) are considerably different in <span class="hlt">marine</span> <span class="hlt">waters</span> from well-known drinking, process and wastewater applications. In contrast, the major secondary oxidants are bromine species in <span class="hlt">marine</span> <span class="hlt">waters</span>, which might form the DBPs of concern bromate and bromoform. An efficient AOP application needs knowledge of the source <span class="hlt">water</span> constitutions and the oxidant demand. Besides changes in the oxidants chemistry compared to fresh <span class="hlt">water</span>, the great and seasonal variation of <span class="hlt">marine</span> <span class="hlt">waters</span> has to be considered in the process design. The complexity of oxidant reactions and formation of byproducts are only partially researched and known as yet. Hence, it is advisable to determine the characteristic and variation of the <span class="hlt">water</span> source as well as its influence on each AOP in experiments prior to the process design.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996GBioC..10..527H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996GBioC..10..527H"><span>Calcite dissolution in sediments of the Ontong-Java Plateau: In situ measurements of <span class="hlt">pore</span> <span class="hlt">water</span> O2 and pH</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hales, Burke; Emerson, Steve</p> <p>1996-09-01</p> <p>We present in situ electrode measurements of sediment resistivity, <span class="hlt">pore</span> <span class="hlt">water</span> oxygen, and <span class="hlt">pore</span> <span class="hlt">water</span> pH from three stations between 2300 and 3000 m depth on the Ontong-Java Plateau in the western equatorial Pacific. One of these stations is also the site of a concurrent benthic chamber incubation experiment [Jahnke et al., 1994]. The <span class="hlt">pore</span> <span class="hlt">water</span> oxygen data and a steady state diffusion and reaction model constrain the depth-dependent rate of oxic respiration in the sediments and imply a diffusive flux of oxygen to the sediments of 10-21 μmol cm-2 yr-1. Given these respiration rates, the <span class="hlt">pore</span> <span class="hlt">water</span> pH data cannot be explained without calcite dissolution driven by metabolically produced CO2. The dissolution necessary to explain the observations, quantified by a statistical approach, is 3.5-6 μmol cm-2 yr-1, which corresponds to at least 20-40% of the calcite rain to these sediments. Over 65% of the total dissolution is driven by metabolic CO2. Oxygen fluxes and net calcite dissolution constrained by the electrode data are compatible with the benthic chamber measurements of Jahnke et al. [1994]. The dissolution flux, while a significant part of the early diagenesis of calcite in these sediments, is less than would be predicted by earlier models of dissolution, and Jahnke et al. [1994] probably could not distinguish it from zero with the benthic chamber technique. The dissolution rates found in this study are lower than previous estimates because the respiration reaction is concentrated near the sediment-<span class="hlt">water</span> interface, and the calcite dissolution rate constants are very small. The statistical evaluation of the <span class="hlt">pore</span> <span class="hlt">water</span> pH data and model constrain the calcite dissolution rate constant to 0.005-0.16% d-1, following the general trend of lower values determined by in situ techniques rather than by laboratory methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26593280','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26593280"><span>Equilibrium passive sampling as a tool to study polycyclic aromatic hydrocarbons in Baltic Sea sediment <span class="hlt">pore-water</span> systems.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lang, Susann-Cathrin; Hursthouse, Andrew; Mayer, Philipp; Kötke, Danjiela; Hand, Ines; Schulz-Bull, Detlef; Witt, Gesine</p> <p>2015-12-15</p> <p>Solid Phase Microextraction (SPME) was applied to provide the first large scale dataset of freely dissolved concentrations for 9 polycyclic aromatic hydrocarbons (PAHs) in Baltic Sea sediment cores. Polydimethylsiloxane (PDMS) coated glass fibers were used for ex-situ equilibrium sampling followed by automated thermal desorption and GC-MS analysis. From the PAH concentrations in the fiber coating we examined (i) spatially resolved freely dissolved PAH concentrations (Cfree); (ii) baseline toxicity potential on the basis of chemical activities (a); (iii) site specific mixture compositions; (iv) diffusion gradients at the sediment <span class="hlt">water</span> interface and within the sediment cores and (v) site specific distribution ratios. Contamination levels were low in the northern Baltic Sea, moderate to elevated in the Baltic Proper and highest in the Gulf of Finland. Chemical activities were well below levels expected to cause narcosis to benthos organisms. The SPME method is a very sensitive tool that opens new possibilities for studying the PAHs at trace levels in <span class="hlt">marine</span> environments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4263649','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4263649"><span>Cortical Bone <span class="hlt">Water</span> Concentration: Dependence of MR Imaging Measures on Age and <span class="hlt">Pore</span> Volume Fraction</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Li, Cheng; Seifert, Alan C.; Rad, Hamidreza Saligheh; Bhagat, Yusuf A.; Rajapakse, Chamith S.; Sun, Wenli; Lam, Shing Chun Benny</p> <p>2014-01-01</p> <p>Purpose To quantify bulk bone <span class="hlt">water</span> to test the hypothesis that bone <span class="hlt">water</span> concentration (BWC) is negatively correlated with bone mineral density (BMD) and is positively correlated with age, and to propose the suppression ratio (SR) (the ratio of signal amplitude without to that with long-T2 suppression) as a potentially stronger surrogate measure of porosity, which is evaluated ex vivo and in vivo. Materials and Methods Human subject studies were conducted in compliance with institutional review board and HIPAA regulations. Healthy men and women (n = 72; age range, 20–80 years) were examined with a hybrid radial ultrashort echo time magnetic resonance (MR) imaging sequence at 3.0 T, and BWC was determined in the tibial midshaft. In a subset of 40 female subjects, the SR was measured with a similar sequence. Cortical volumetric BMD (vBMD) was measured by means of peripheral quantitative computed tomography (CT). The method was validated against micro-CT–derived porosity in 13 donor human cortical bone specimens. Associations among parameters were evaluated by using standard statistical tools. Results BWC was positively correlated with age (r = 0.52; 95% confidence interval [CI]: 0.22, 0.73; P = .002) and negatively correlated with vBMD at the same location (r = −0.57; 95% CI: −0.76, −0.29; P < .001). Data were suggestive of stronger associations with SR (r = 0.64, 95% CI: 0.39, 0.81, P < .001 for age; r = −0.67, 95% CI: −0.82, −0.43, P < .001 for vBMD; P < .001 for both), indicating that SR may be a more direct measure of porosity. This interpretation was supported by ex vivo measurements showing SR to be strongly positively correlated with micro-CT porosity (r = 0.88; 95% CI: 0.64, 0.96; P < .001) and with age (r = 0.87; 95% CI: 0.62, 0.96; P < .001). Conclusion The MR imaging–derived SR may serve as a biomarker for cortical bone porosity that is potentially superior to BWC, but corroboration in larger cohorts is indicated. © RSNA, 2014 PMID</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/402391','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/402391"><span>Produced <span class="hlt">water</span> toxicity tests accurately measure the produced <span class="hlt">water</span> toxicity in <span class="hlt">marine</span> environments?</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Douglas, W.S.; Veil, J.A.</p> <p>1996-10-01</p> <p>U.S. Environmental Protection Agency (EPA) Region VI has issued a general permit for offshore oil and gas discharges to the Gulf of Mexico that places numerical limits on whole effluent toxicity (WEI) for produced <span class="hlt">water</span>. Recently proposed EPA general permits for other produced <span class="hlt">water</span> discharges in Regions VI and X also include enforceable numerical limits on WET. Clearly, the industry will be conducting extensive produced <span class="hlt">water</span> WET testing. Unfortunately, the WET test may not accurately measure the toxicity of the chemical constituents of produced <span class="hlt">water</span>. Rather the mortality of test organisms may be attributable to (1) the high salinity of produced <span class="hlt">water</span>, which causes salinity shock to the organisms, or (2) an ionic imbalance caused by excesses or deficiencies of one or more of seawater`s essential ions in the test chambers. Both of these effects are likely to be mitigated in actual offshore discharge settings, where the receiving <span class="hlt">water</span> will be seawater and substantial dilution will be probable. Thus, the additional salinity of produced <span class="hlt">water</span> will be rapidly assimilated, and the proper <span class="hlt">marine</span> ionic balance will be quickly restored. Regulatory authorities should be aware of these factors when interpreting WET test results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title33-vol2/pdf/CFR-2010-title33-vol2-sec165-514.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title33-vol2/pdf/CFR-2010-title33-vol2-sec165-514.pdf"><span>33 CFR 165.514 - Safety Zone: Atlantic Intracoastal Waterway and connecting <span class="hlt">waters</span>, vicinity of <span class="hlt">Marine</span> Corps Base...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-07-01</p> <p>... Intracoastal Waterway and connecting <span class="hlt">waters</span>, vicinity of <span class="hlt">Marine</span> Corps Base Camp Lejeune, North Carolina. 165... Intracoastal Waterway and connecting <span class="hlt">waters</span>, vicinity of <span class="hlt">Marine</span> Corps Base Camp Lejeune, North Carolina. (a... from <span class="hlt">Marine</span> Corps Base Camp Lejeune will be suspended and vessels permitted to transit the specified...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA....11567T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA....11567T"><span>Carbonate cementation by cold <span class="hlt">marine</span> <span class="hlt">waters</span>: evidence from carbonate mounds at the NE Atlantic margin.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Taberner, C.; Richter, T. O.; van Weering, T. C. E.; Vonhof, H. B.; Stadnitskaya, A.</p> <p>2003-04-01</p> <p>Cementation of <span class="hlt">marine</span> carbonate sediments by <span class="hlt">marine</span> <span class="hlt">waters</span> is well known to occur either in shallow tropical to temperate carbonate platforms, or during burial from modified interstitial brines. Cementation by cold <span class="hlt">marine</span> <span class="hlt">waters</span> is traditionally ruled out for both recent and fossil carbonates. We present petrographic and stable isotope (δ18O, δ13C) results on well-cemented carbonates from cold-<span class="hlt">water</span> carbonate mounds at the SW and SE Rockall Margin (700--800m <span class="hlt">water</span> depth). Calcite micritic cements, as well as concentrically zoned microspar filling cavities (e.g. foraminifera), have been recognised in dredged hardground samples and carbonate concretions from sediment cores. Microsampled cements have δ13C and δ18O values (respectively ≈+3.5 ppm PDB and ≈+5 ppm PDB) that appear to be in equilibrium with glacial intermediate <span class="hlt">waters</span>, more than with present-day Atlantic <span class="hlt">waters</span> at those depths. Cementation during glacial intervals is also indicated by AMS 14C ages of well-cemented deep-<span class="hlt">water</span> carbonate rocks (hardgrounds) of 25--29ka, thus bracketing the <span class="hlt">marine</span> isotope stage 3/2 boundary. These data provide evidence for carbonate cementation by cold <span class="hlt">marine</span> <span class="hlt">waters</span> and have implications for the paleoceanographic interpretation of deep-<span class="hlt">water</span> carbonate mounds. Additionally, these results provide new insights for the re-evaluation of the depth of deposition of carbonate mounds from the geological record.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.B51J0140P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.B51J0140P"><span>Evidence of Chlorobenzene Natural Attenuation in Contaminated Sediments Using Compound Specific Isotope Analysis and High Resolution <span class="hlt">Pore</span> <span class="hlt">Water</span> Sampling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Passeport, E.; Landis, R.; Lacrampe Couloume, G.; Lutz, E. J.; Mack, E. E.; West, K.; Sherwood Lollar, B.</p> <p>2014-12-01</p> <p>Contaminated sediments can represent a significant risk for ecosystems and hinder drinking <span class="hlt">water</span> production if contaminants discharge to surface and ground <span class="hlt">water</span>. Understanding of contaminant fate and the potential for natural attenuation can help protect aquatic resources. In this study, the fate of chlorobenzene (MCB) and benzene was investigated in a contaminated canal sediment field site located in New Jersey, USA. Compound Specific Isotope Analysis (CSIA) was applied to sediment <span class="hlt">pore</span> <span class="hlt">water</span> samples collected with a peeper at high spatial resolution (3 cm) across the sediment - surface <span class="hlt">water</span> interface (SWI). Samples were collected at three locations in canal sediments, all of which exhibited reducing redox conditions. The largest concentrations were observed in the bottommost portions of the sediment profile, with concentrations ranging from 300 to 2000 µg/L for MCB, and 16 to 180 µg/L for benzene. Conversely, concentrations were below detection limit in the surface <span class="hlt">water</span> and in the top 6 cm of the sediment. In the zones of highest MCB concentrations, the δ13C values were -26.4 (location C) and -21.9 ‰ (location F), and became progressively more enriched in 13C while concentrations decreased, reaching -23.9 (at 12 cm below the SWI, location C) and -18.4 ‰ (at 16.5 cm below SWI, location F). Benzene was only detected in the bottom 6 cm of the sediment profiles. Benzene δ13C values were -27 (bottommost, i.e., 24 cm deep) to -29.7 ‰ (18 cm deep), in location C. Such significant isotopic enrichments in 13C (2.5 to 3.5 ‰) correlated with MCB and benzene concentration decrease are suggestive of in situ biodegradation. In addition, benzene δ13C values were systematically more depleted in 13C than MCB, suggesting that benzene found in these zones was likely produced from MCB via reductive dechlorination. This study combined for the first time CSIA with high spatial sampling resolution in surface <span class="hlt">water</span> sediments. This setup enabled not only detection of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JGRG..118..825D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRG..118..825D"><span>Legacy mercury and stoichiometry with C, N, and S in soil, <span class="hlt">pore</span> <span class="hlt">water</span>, and stream <span class="hlt">water</span> across the upland-wetland interface: The influence of hydrogeologic setting</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Demers, Jason D.; Yavitt, Joseph B.; Driscoll, Charles T.; Montesdeoca, Mario R.</p> <p>2013-06-01</p> <p>Mechanisms influencing retention, biogeochemical cycling, and release of legacy mercury within soils of forests and wetlands remain poorly understood. We quantified mercury pool size and stoichiometry with carbon, nitrogen, and sulfur across forest-wetland transects and among wetlands of different hydrogeologic settings in the Adirondack region of New York State. Average total mercury pool size in soils (to 50 cm depth) was greater in forests (17.5 mg/m2) than in wetlands (6.1 mg/m2; p < 0.010). The average mercury pool size (to 50 cm depth) in shallow-peat riparian wetlands (9.3 mg/m2) was greater than in deep-peat riparian (5.4 mg/m2; p = 0.099) or headwater wetlands (3.6 mg/m2; p = 0.046). Accumulation of mercury was enhanced at the forest-wetland interface. In mineral horizons of the forest soil and in shallow-peat riparian wetlands, mercury was positively correlated with carbon (r2 = 0.73-0.96) and nitrogen (r2 = 0.82-0.93), but not sulfur. In contrast, mercury and sulfur were strongly correlated in headwater wetland peat (r2 = 0.73). Dissolved mercury was correlated with dissolved organic carbon (DOC) in <span class="hlt">pore</span> <span class="hlt">water</span> and stream <span class="hlt">water</span> of deep-peat and shallow-peat riparian wetlands (r2 = 0.46-0.73), but not in headwater wetland <span class="hlt">pore</span> <span class="hlt">water</span>. In headwater outlet streams, dissolved mercury was correlated with DOC (r2 = 0.62), but the slope was only one third that in riparian streams. Hydrogeologic setting influences decomposition processes, biogeochemical cycling of mercury, and hydrologic transport that in turn, govern the size and stoichiometry of mercury pools across the upland-wetland interface and among different wetland types. Ultimately, mobilization of legacy mercury into aquatic ecosystems from forest soils and wetlands likely depends upon decomposition dynamics and hydrologic flow paths.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21574403','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21574403"><span>[Determination of tracer gas contents in sediment <span class="hlt">pore</span> <span class="hlt">water</span> of gas hydrate area by two-dimensional gas chromatography].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Hu; Yang, Qunhui; Ji, Fuwu; Zhou, Huaiyang; Xue, Xiang</p> <p>2011-01-01</p> <p>A two-dimensional gas chromatographic instrument was established by the capillary flow technology (Deans Switch) and two columns (PoraPLOT Q and Molsieve 5A) and three detectors (pulsed discharge helium ionization detector, flame photometric detector and thermal conductivity detector). The instrument can be used to measure tracer gases simultaneously including hydrogen, methane, carbon dioxide and hydrogen sulfide. The detection limits of the hydrogen, methane, carbon dioxide and hydrogen sulfide were 0.51, 0.17, 82 and 0.08 micromol/mol, and the calibration curves presented good linear relationships in the range of 2-1030, 0.6-501, 120-10500 and 0.2- 49.1 micromol/mol, respectively. The relative standard deviations were less than 10% for the measurements of ten standard gases. By this method, the tracer gases in the sediment <span class="hlt">pore</span> <span class="hlt">water</span> of gas hydrate area in South China Sea had been detected. This method is simple, sensitive, and suitable for on-board detection. Compared with the usual methods for measuring tracer gases, the amount of a sample necessary is reduced greatly. It is useful for the survey of gas hydrate and hydrothermal resources below sea floor and for the research of dissolved gases in the ocean.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/875976','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/875976"><span>Measurement and modeling of energetic material mass transfer to soil <span class="hlt">pore</span> <span class="hlt">water</span> :project CP-1227 FY03 annual technical report.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Phelan, James M.; Barnett, James L.; Kerr, Dayle R.</p> <p>2004-01-01</p> <p>Military test and training ranges operate with live fire engagements to provide realism important to the maintenance of key tactical skills. Ordnance detonations during these operations typically produce minute residues of parent explosive chemical compounds. Occasional low order detonations also disperse solid phase energetic material onto the surface soil. These detonation remnants are implicated in chemical contamination impacts to groundwater on a limited set of ranges where environmental characterization projects have occurred. Key questions arise regarding how these residues and the environmental conditions (e.g., weather and geostratigraphy) contribute to groundwater pollution impacts. This report documents interim results of experimental work evaluating mass transfer processes from solid phase energetics to soil <span class="hlt">pore</span> <span class="hlt">water</span>. The experimental work is used as a basis to formulate a mass transfer numerical model, which has been incorporated into the porous media simulation code T2TNT. This report documents the results of the Phase III experimental effort, which evaluated the impacts of surface deposits versus buried deposits, energetic material particle size, and low order detonation debris. Next year, the energetic material mass transfer model will be refined and a 2-d screening model will be developed for initial site-specific applications. A technology development roadmap was created to show how specific R&D efforts are linked to technology and products for key customers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28122673','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28122673"><span>Mechanisms of nickel toxicity to fish and invertebrates in <span class="hlt">marine</span> and estuarine <span class="hlt">waters</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Blewett, Tamzin A; Leonard, Erin M</p> <p>2017-04-01</p> <p>In freshwater settings the toxicity of the trace metal nickel (Ni) is relatively well understood. However, until recently, there was little knowledge regarding Ni toxicity in <span class="hlt">waters</span> of higher salinity, where factors such as <span class="hlt">water</span> chemistry and the physiology of estuarine and <span class="hlt">marine</span> biota would be expected to alter toxicological impact. This review summarizes recent literature investigating Ni toxicity in <span class="hlt">marine</span> and estuarine invertebrates and fish. As in freshwater, three main mechanisms of Ni toxicity exist: ionoregulatory impairment, inhibition of respiration, and promotion of oxidative stress. However, unlike in freshwater biota, where mechanisms of toxicity are largely Class-specific, the delineation of toxic mechanisms between different species is less defined. In general, despite changes in Ni speciation in <span class="hlt">marine</span> <span class="hlt">waters</span>, organism physiology appears to be the main driver of toxic impact, a fact that will need to be accounted for when adapting regulatory tools (such as bioavailability normalization) from freshwater to estuarine and <span class="hlt">marine</span> environments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ERL.....9j9001T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ERL.....9j9001T"><span>Comment on ‘<span class="hlt">Water</span> footprint of <span class="hlt">marine</span> protein consumption—aquaculture’s link to agriculture’</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Troell, Max; Metian, Marc; Beveridge, Malcolm; Verdegem, Marc; Deutsch, Lisa</p> <p>2014-10-01</p> <p>In their article ‘Freshwater savings from <span class="hlt">marine</span> protein consumption’ (2014 Environ. Res. Lett. 9 014005), Gephart and her colleagues analyzed how consumption of <span class="hlt">marine</span> animal protein rather than terrestrial animal protein leads to reduced freshwater allocation. They concluded that future <span class="hlt">water</span> savings from increased <span class="hlt">marine</span> fish consumption would be possible. We find the approach interesting and, if they only considered <span class="hlt">marine</span> capture fisheries, their analysis would be quite straightforward and show savings of freshwater. However, both capture fisheries and aquaculture are considered in the analysis, and the fact that <span class="hlt">marine</span> aquaculture is assumed to have a zero freshwater usage, makes the analysis incomplete. Feed resources used in <span class="hlt">marine</span> aquaculture contain agriculture compounds, which results in a freshwater footprint. To correct this shortcoming we complement the approach taken by Gephart and her colleagues by estimating the freshwater footprint (WF) for crops used for feeding <span class="hlt">marine</span> aquaculture. We show that this is critically important when estimating the true freshwater footprint for <span class="hlt">marine</span> aquaculture, and that it will be increasingly so in the future. We also further expand on aquaculture’s dependency on fish resources, as this was only briefly touched upon in the paper. We do so because changes in availability of fish resources will play an important role for feed development and thereby for the future freshwater footprint of <span class="hlt">marine</span> aquaculture.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=115261&keyword=roles+AND+distribution&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=84621730&CFTOKEN=82079289','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=115261&keyword=roles+AND+distribution&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=84621730&CFTOKEN=82079289"><span>IMPORTANCE OF BLACK CARBON IN DISTRIBUTION AND BIOACCUMULATION MODELS OF POLYCYCLIC AROMATIC HYDROCARBONS IN CONTAMINATED <span class="hlt">MARINE</span> SEDIMENTS</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>The roles and relative importance of nonpyrogenic organic carbon (NPOC) and black carbon (BC) as binding phases of polycyclic aromatic hydrocarbons (PAHs) were assessed by their ability to estimate <span class="hlt">pore</span> <span class="hlt">water</span> concentrations and biological uptake in various <span class="hlt">marine</span> sediments. Sedim...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004JCHyd..75...31L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004JCHyd..75...31L"><span><span class="hlt">Water</span>-soluble gases as partitioning tracers to investigate the <span class="hlt">pore</span> volume?transmissivity correlation in a fracture</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lunati, Ivan; Kinzelbach, Wolfgang</p> <p>2004-11-01</p> <p>Hydraulically equivalent fractures may show striking differences when a gas-migration experiment is performed because of the different correlations between transmissivity, <span class="hlt">pore</span> volume and entry pressure. We numerically simulate gas migration between injection and extraction boreholes in a parallel plate fracture with a heterogeneous fault gouge, in a rough-walled fracture filled with homogeneous material, and in a rough-walled empty fracture. The parallel plate model and the empty model clearly show the existence of preferential paths; for high variance of the transmissivity field, gas flow takes place only in few discrete channels separated by <span class="hlt">water</span>-saturated regions. In contrast, in the fracture filled with homogeneous fault gouge, the gas saturation is continuous and more uniformly distributed. It appears a fundamental issue to be able to discriminate in situ among conceptual models that can yield such a different gas-saturation distribution. As in practice, the saturation distribution cannot be directly observed, tracer experiments are performed to characterize a fracture. For these reasons, we simulate the transport of tracers, which are added to the gas phase as soon as quasi-steady saturation distribution and extraction rate are achieved, and we compare the breakthrough curves obtained assuming different models. Our numerical simulations suggest that discrimination among the models on the basis of single-tracer tests is unlikely. A better tool to investigate fracture properties is provided by a gas-tracer test, in which a cocktail of gases with different <span class="hlt">water</span> solubility is employed. These gases behave as partitioning tracers and allow us to estimate the gas saturation in the fracture. Indeed, by comparison of the residence-time distributions of different gases, we are able to compute a streamline effective saturation, which is an excellent estimate of fracture saturation. In addition, the streamline effective saturation curve contains information that is</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.H51K..06B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.H51K..06B"><span>Using <span class="hlt">Pore</span> <span class="hlt">Water</span> Chemistry to Understand Critical Zone Mineral Weathering Reactions: A Comparison of Three Tropical Watersheds</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Buss, H. L.; White, A. F.; Dessert, C.; Gaillardet, J.</p> <p>2007-12-01</p> <p>Geochemical, physical, biological, and hydrologic processes are tightly coupled within the critical zone and impact global and local <span class="hlt">water</span> cycles, solute movement, weathering rates, and nutrient bioavailability. The weathering of primary minerals in regolith and at bedrock-regolith interfaces directly impacts the availability of many important soil nutrients including Mg, Ca, K, PO4, and Fe. However, surprisingly little biogeochemical data exists as a function of depth in terrestrial regolith below the rooting zone. This shortage of data hinders quantification of the coupled processes that control nutrient fluxes. Installation of nested suction soil <span class="hlt">water</span> samplers enables multiple researchers to measure biogeochemical parameters as a function of depth. Nested suction <span class="hlt">water</span> samplers have been installed in soil and regolith at 0.15 m to as deep as 16.0 m in two watersheds in the Luquillo Mountains of Puerto Rico and in a watershed on Basse-Terre, Guadeloupe, in the French Antilles. All three watersheds are steep, rugged, humid, and tropical, have similar vegetation and land- use, and contain thick saprolites developed on volcanic materials: a quartz diorite intrusion in the Rio Icacos watershed, Puerto Rico; <span class="hlt">marine</span> bedded volcaniclastics in the Bisley watershed, Puerto Rico; and a volcanic debris flow in the Bras-David watershed, Guadeloupe. The two Puerto Rican watersheds are part of the USGS <span class="hlt">Water</span> Energy and Biogeochemical Budgets (WEBB) program and also constitute a Critical Zone Exploration Network (CZEN) seed site. The Bisley watershed is also part of the Luquillo Long Term Ecological Research (LTER) site. The Guadeloupean watershed is a Critical Zone International Scholar seed site and the surface <span class="hlt">water</span> chemistry is monitored by the Observatoire Volcanologique et Sismologique de Guadeloupe and the Institut de Physique du Globe de Paris (IPGP). In the mid 1990's the Rio Icacos watershed was instrumented with regolith gas samplers, tensiometers, and nested</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011BGD.....8.9763F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011BGD.....8.9763F"><span>Interaction between hydrocarbon seepage, chemosynthetic communities and bottom <span class="hlt">water</span> redox at cold seeps of the Makran accretionary prism: insights from habitat-specific <span class="hlt">pore</span> <span class="hlt">water</span> sampling and modeling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fischer, D.; Sahling, H.; Nöthen, K.; Bohrmann, G.; Zabel, M.; Kasten, S.</p> <p>2011-09-01</p> <p>The interaction between fluid seepage, bottom <span class="hlt">water</span> redox, and chemosynthetic communities was studied at cold seeps across one of the world's largest oxygen minimum zones (OMZ) located at the Makran convergent continental margin. Push cores were obtained from seeps within and at the lower boundary of the core-OMZ with a remotely operated vehicle. Extracted <span class="hlt">pore</span> <span class="hlt">water</span> was analyzed for sulfide and sulfate contents. Depending on oxygen availability, seeps were either colonized by microbial mats or by mats and macrofauna. The latter, including ampharetid polychaetes and vesicomyid clams, occurred in distinct benthic habitats which were arranged in a concentric fashion around gas orifices. At most sites colonized by microbial mats, hydrogen sulfide was exported into the bottom <span class="hlt">water</span>. Where macrofauna was widely abundant, hydrogen sulfide was consumed within the sediment. Numerical modeling of <span class="hlt">pore</span> <span class="hlt">water</span> profiles was performed in order to assess rates of fluid advection and bioirrigation. While the magnitude of upward fluid flow decreased from 11 cm yr-1 to <1 cm yr-1 and the sulfate/methane transition zone (SMTZ) deepened with increasing distance from the central gas orifice, the fluxes of sulfate into the SMTZ did not significantly differ (6.6-9.3 mol m-2 yr-1). Depth-integrated rates of bioirrigation increased from 162 cm yr-1 in central habitats characterized by microbial mats and sparse macrofauna to 348 cm yr-1 in habitats of large and small vesicomyid clams. These results reveal that chemosynthetic macrofauna inhabiting the outer seep habitats at the lower boundary of the OMZ efficiently bioirrigate and thus transport sulfate into the upper 10 to 15 cm of the sediment. In this way bioirrigation compensates for the lower upward flux of methane in outer habitats and stimulates rates of anaerobic oxidation of methane (AOM) with sulfate high enough to provide sulfide for chemosynthesis. Through bioirrigation macrofauna engineer their geochemical environment and fuel</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22296346','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22296346"><span>Role of dense shelf <span class="hlt">water</span> cascading in the transfer of organochlorine compounds to open <span class="hlt">marine</span> <span class="hlt">waters</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Salvadó, Joan A; Grimalt, Joan O; López, Jordi F; Palanques, Albert; Heussner, Serge; Pasqual, Catalina; Sanchez-Vidal, Anna; Canals, Miquel</p> <p>2012-03-06</p> <p>Settling particles were collected by an array of sediment trap moorings deployed along the Cap de Creus (CCC) and Lacaze-Duthiers (LDC) submarine canyons and on the adjacent southern open slope (SOS) between October 2005 and October 2006. This array collected particles during common settling processes and particles transferred to deep <span class="hlt">waters</span> by dense shelf <span class="hlt">water</span> cascading (DSWC). Polychlorobiphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), chlorobenzenes (CBzs)--pentachlorobenzene and hexachlorobenzene--and hexachlorocyclohexanes were analyzed in all samples. The results show much higher settling fluxes of these compounds during DSWC than during common sedimentation processes. The area of highest deposition was located between 1000 and 1500 m depth and extended along the canyons and outside them showing their channelling effects but also overflows of dense shelf <span class="hlt">water</span> from these canyons. Higher fluxes were observed near the bottom (30 m above bottom; mab) than at intermediate <span class="hlt">waters</span> (500 mab) which is consistent with the formation and sinking of dense <span class="hlt">water</span> close to the continental shelf and main displacement through the slope by the bottom. DSWC involved the highest settling fluxes of these compounds ever described in <span class="hlt">marine</span> continental slopes and pelagic areas, e.g., peak values of PCBs (960 ng · m(-2) · d(-1)), DDTs (2900 ng · m(-2) · d(-1)), CBzs (340 ng · m(-2) · d(-1)) and lindane (180 ng · m(-2) · d(-1)).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27771099','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27771099"><span>Escherichia coli in <span class="hlt">marine</span> <span class="hlt">water</span>: Comparison of methods for the assessment of recreational bathing <span class="hlt">water</span> samples.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lušić, Darija Vukić; Jozić, Slaven; Cenov, Arijana; Glad, Marin; Bulić, Marko; Lušić, Dražen</p> <p>2016-12-15</p> <p>Bathing <span class="hlt">Water</span> Directive (2006/7/EC) specifies two reference methods for Escherichia coli detection: ISO 9308-1 and 9308-3. The revised ISO 9308-1 is recommended only for <span class="hlt">waters</span> with a low bacterial background flora. Considering the extended time needed for analysis and, generally, the lack of experience in using ISO 9308-3 in the Mediterranean, the suitability of ISO 9308-1 for the examination of E. coli in bathing <span class="hlt">water</span> was evaluated. The present study was aimed at a comparison of data obtained by the reference method in seawater samples (110 beaches, N=477) with data received from six alternative methods. Results show that recently used TSA/TBA method may overestimate E. coli numbers in <span class="hlt">marine</span> <span class="hlt">waters</span>. The temperature modified ISO 9308-1 (44°C) did not significantly alter the results, but outperformed the antibiotic supplemented agar at reducing non-E. coli bacteria on the plates, allowing the use of the respective method for monitoring coastal <span class="hlt">water</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/ds/375/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/ds/375/"><span>Total Mercury, Methylmercury, Methylmercury Production Potential, and Ancillary Streambed-Sediment and <span class="hlt">Pore-Water</span> Data for Selected Streams in Oregon, Wisconsin, and Florida, 2003-04</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Marvin-DiPasquale, Mark C.; Lutz, Michelle A.; Krabbenhoft, David P.; Aiken, George R.; Orem, William H.; Hall, Britt D.; DeWild, John F.; Brigham, Mark E.</p> <p>2008-01-01</p> <p>Mercury contamination of aquatic ecosystems is an issue of national concern, affecting both wildlife and human health. Detailed information on mercury cycling and food-web bioaccumulation in stream settings and the factors that control these processes is currently limited. In response, the U.S. Geological Survey (USGS) National <span class="hlt">Water</span>-Quality Assessment Program (NAWQA) conducted detailed studies from 2002 to 2006 on various media to enhance process-level understanding of mercury contamination, biogeochemical cycling, and trophic transfer. Eight streams were sampled for this study: two streams in Oregon, and three streams each in Wisconsin and Florida. Streambed-sediment and <span class="hlt">pore-water</span> samples were collected between February 2003 and September 2004. This report summarizes the suite of geochemical and microbial constituents measured, the analytical methods used, and provides the raw data in electronic form for both bed-sediment and <span class="hlt">pore-water</span> media associated with this study.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2012-02-27/pdf/2012-4469.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2012-02-27/pdf/2012-4469.pdf"><span>77 FR 11401 - <span class="hlt">Marine</span> Sanitation Devices (MSDs): No Discharge Zone (NDZ) for California State <span class="hlt">Marine</span> <span class="hlt">Waters</span></span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2012-02-27</p> <p>... quality impairments and impacts to sensitive <span class="hlt">marine</span> habitats. In 2000, an Alaska Cruise Ship Initiative study sampled 21 cruise ships twice during the cruise season and found that 57 percent of the samples... Environmental Conservation, ``Alaska Cruise Ship Initiative, Part 2 Report'' (2001), available at...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70024895','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70024895"><span>Effects of <span class="hlt">pore-water</span> ammonia on in situ survival and growth of juvenile mussels (Lampsilis cardium) in the St. Croix Riverway, Wisconsin, USA</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bartsch, M.R.; Newton, T.J.; Allran, J.W.; O'Donnell, J. A.; Richardson, W.B.</p> <p>2003-01-01</p> <p>We conducted a series of in situ tests to evaluate the effects of <span class="hlt">pore-water</span> ammonia on juvenile Lampsilis cardium in the St. Croix River (WI, USA). Threats to this river and its associated unionid fauna have accelerated in recent years because of its proximity to Minneapolis-St. Paul, Minnesota, USA. In 2000, caged juveniles were exposed to sediments and overlying <span class="hlt">water</span> at 12 sites for 10 d. Survival and growth of juveniles was significantly different between sediment (mean, 47%) and <span class="hlt">water</span> column (mean, 86%) exposures; however, these effects were unrelated to <span class="hlt">pore-water</span> ammonia. During 2001, juveniles were exposed to sediments for 4, 10, and 28 d. <span class="hlt">Pore-water</span> ammonia concentrations ranged from 0.3 to 62.0 ??g NH3-NIL in sediments and from 0.5 to 140.8 ??g NH3-N/L within exposure chambers. Survival (mean, 45, 28, and 41% at 4, 10, and 28 d, respectively) and growth (range, 3-45 ??,m/d) of juveniles were highly variable and generally unrelated to ammonia concentrations. Although laboratory studies have shown unionids to be quite sensitive to ammonia, further research is needed to identify the route(s) of ammonia exposure in unionids and to understand the factors that contribute to the spatial variability of ammonia in rivers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70006707','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70006707"><span>Effects of <span class="hlt">pore-water</span> ammonia on in situ survival and growth of juvenile mussels (Lampsilis cardium) in the St. Croix Riverway, Wisconsin, USA</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bartsch, Michelle; Newton, Teresa J.; Allran, John W.; O'Donnell, Jonathan A.; Richardson, William B.</p> <p>2003-01-01</p> <p>We conducted a series of in situ tests to evaluate the effects of <span class="hlt">pore-water</span> ammonia on juvenile Lampsilis cardium in the St. Croix River (WI, USA). Threats to this river and its associated unionid fauna have accelerated in recent years because of its proximity to Minneapolis-St. Paul, Minnesota, USA. In 2000, caged juveniles were exposed to sediments and overlying <span class="hlt">water</span> at 12 sites for 10 d. Survival and growth of juveniles was significantly different between sediment (mean, 47%) and <span class="hlt">water</span> column (mean, 86%) exposures; however, these effects were unrelated to <span class="hlt">pore-water</span> ammonia. During 2001, juveniles were exposed to sediments for 4, 10, and 28 d. <span class="hlt">Pore-water</span> ammonia concentrations ranged from 0.3 to 62.0 μg NH3-N/L in sediments and from 0.5 to 140.8 μg NH3-N/L within exposure chambers. Survival (mean, 45, 28, and 41% at 4, 10, and 28 d, respectively) and growth (range, 3-45 μm/d) of juveniles were highly variable and generally unrelated to ammonia concentrations. Although laboratory studies have shown unionids to be quite sensitive to ammonia, further research is needed to identify the route(s) of ammonia exposure in unionids and to understand the factors that contribute to the spatial variability of ammonia in rivers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..DFDM40001L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..DFDM40001L"><span>Experimental quantification of <span class="hlt">pore</span>-scale flow of <span class="hlt">water</span> and liquid CO2 in 2D heterogeneous porous micromodels at reservoir conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Yaofa; Kazemifar, Farzan; Blois, Gianluca; Christensen, Kenneth</p> <p>2016-11-01</p> <p><span class="hlt">Pore</span>-scale flow interactions between <span class="hlt">water</span> and supercritical CO2 is relevant to large-scale geologic sequestration of CO2. Recent studies have provided evidence of strong instabilities at the meniscus resulting in burst events and onset of inertial effects. This supports the notion that <span class="hlt">pore</span>-scale physics cannot be captured by Darcian models and unsteady events play a defining role in CO2 transport/trapping processes and such burst events may generate pressure fluctuations that can be linked to micro-seismic events in the <span class="hlt">pore</span> structure. To this end, the <span class="hlt">pore</span>-scale flow of <span class="hlt">water</span> and liquid/supercritical CO2 is investigated under reservoir-relevant conditions in 2D heterogeneous porous micro-models that reflect the complexity of a real sandstone. Fluorescent microscopy and micro-PIV are complemented by a fast differential pressure transmitter, allowing for simultaneous quantification of the flow field within and the instantaneous pressure drop across the micromodels. A number of CO2 invasion patterns and corresponding pressure drop variations are observed over a range of wettability conditions, yielding a more comprehensive picture of the CO2 drainage processes. This work was primarily supported as part of the Center for Geologic Storage of CO2 , an EFRC funded by the U.S. Department of Energy, Office of Science and partially supported by WPI-I2CNER based at Kyushu University, Japan.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001E%26PSL.192....1P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001E%26PSL.192....1P"><span>Oxygen isotopic composition of the Mediterranean Sea since the Last Glacial Maximum: constraints from <span class="hlt">pore</span> <span class="hlt">water</span> analyses</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Paul, Hilary A.; Bernasconi, Stefano M.; Schmid, Daniel W.; McKenzie, Judith A.</p> <p>2001-09-01</p> <p>Interstitial <span class="hlt">waters</span> recovered from Ocean Drilling Program, Leg 161, site 976 in the western Mediterranean Sea are used in conjunction with a numerical model to constrain the δ 18O of seawater in the basin since the Last Glacial Maximum, including Sapropel Event 1. To resolve the oxygen isotopic composition of the deep Mediterranean, we use a model that couples fluid diffusion with advective transport, thus producing a profile of seawater δ 18O variability that is unaffected by glacial-interglacial variations in <span class="hlt">marine</span> temperature. Comparing our reconstructed seawater δ 18O to recent determinations of 1.0‰ for the mean ocean change in glacial-interglacial δ 18O due to the expansion of global ice volume, we calculate an additional 0.2‰ increase in Mediterranean δ 18O caused by local evaporative enrichment. This estimate of δ 18O change, due to salinity variability, is smaller than previous studies have proposed and demonstrates that Mediterranean records of foraminiferal calcite δ 18O from the last glacial period include a strong temperature component. Paleotemperatures determined in combination with a stacked record of foraminiferal calcite depict almost 9°C of regional cooling for the Last Glacial Maximum. Model results suggest a decrease of ˜1.1‰ in seawater δ 18O relative to the modern value caused by increased freshwater input and reduced salinity accompanying the formation of the most recent sapropel. The results additionally indicate the existence of isotopically light <span class="hlt">water</span> circulating down to bottom <span class="hlt">water</span> depths, at least in the western Mediterranean, supporting the existence of an 'anti-estuarine' thermohaline circulation pattern during Sapropel Event 1.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17568653','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17568653"><span>Effect of overlying <span class="hlt">water</span> pH, dissolved oxygen, salinity and sediment disturbances on metal release and sequestration from metal contaminated <span class="hlt">marine</span> sediments.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Atkinson, Clare A; Jolley, Dianne F; Simpson, Stuart L</p> <p>2007-11-01</p> <p>Experiments were undertaken to examine the key variables affecting metal release and sequestration processes in <span class="hlt">marine</span> sediments with metal concentrations in sediments reaching up to 86, 240, 700, and 3000 mg kg(-1) (dry weight) for Cd, Cu, Pb and Zn, respectively. The metal release and sequestration rates were affected to a much greater extent by changes in overlying <span class="hlt">water</span> pH (5.5-8.0) and sediment disturbance (by physical mixing) than by changes in dissolved oxygen concentration (3-8 mg l(-1)) or salinity (15-45 practical salinity units). The physical disturbance of sediments was also found to release metals more rapidly than biological disturbance (bioturbation). The rate of oxidative precipitation of released iron and manganese increased as pH decreased and appeared to greatly influence the sequestration rate of released lead and zinc. Released metals were sequestered less rapidly in <span class="hlt">waters</span> with lower dissolved oxygen concentrations. Sediments bioturbated by the benthic bivalve Tellina deltoidalis caused metal release from the <span class="hlt">pore</span> <span class="hlt">waters</span> and higher concentrations of iron and manganese in overlying <span class="hlt">waters</span> than non-bioturbated sediments. During 21-day sediment exposures, T. deltoidalis accumulated significantly higher tissue concentrations of cadmium, lead and zinc from the metal contaminated sediments compared to controls. This study suggests that despite the fact that lead and zinc were most likely bound as sulfide phases in deeper sediments, the metals maintain their bioavailability because of the continued cycling between <span class="hlt">pore</span> <span class="hlt">waters</span> and surface sediments due to physical mixing and bioturbation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007GeCoA..71.3272T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007GeCoA..71.3272T"><span>Lipids of <span class="hlt">marine</span> Archaea: Patterns and provenance in the <span class="hlt">water</span>-column and sediments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Turich, Courtney; Freeman, Katherine H.; Bruns, Mary Ann; Conte, Maureen; Jones, A. Daniel; Wakeham, Stuart G.</p> <p>2007-07-01</p> <p>We measured archaeal lipid distributions from globally distributed samples of freshwater, <span class="hlt">marine</span>, and hypersaline suspended particulate matter. Cluster analysis of relative lipid distributions identified four distinct groups, including: (1) <span class="hlt">marine</span> epipelagic (<100 m) <span class="hlt">waters</span>, (2) <span class="hlt">marine</span> mesopelagic (200-1500 m) and upwelling <span class="hlt">waters</span>, (3) freshwater/estuarine <span class="hlt">waters</span>, and (4) hypersaline <span class="hlt">waters</span>. A pronounced difference in lipid composition patterns is the near absence of ring-containing glycerol dialkyl glycerol tetraethers (GDGTs) at high salinity. Different archaeal communities populate <span class="hlt">marine</span> (mesophilic Crenarchaeota and Euryarchaeota), and hypersaline environments (halophilic Euryarchaeota) and community shifts can regulate differences in lipid patterns between <span class="hlt">marine</span> and hypersaline <span class="hlt">waters</span>. We propose that community changes within meosphilic <span class="hlt">marine</span> Archaea also regulate the lipid patterns distinguishing epipelagic and mesopelagic/upwelling zones. Changes in the relative amounts of crenarchaeol and caldarchaeol and low relative abundances of ringed structures in surface <span class="hlt">waters</span> differentiate lipids from the epipelagic and mesopelagic/upwelling <span class="hlt">waters</span>. Patterns of lipids in mesopelagic (and upwelling) <span class="hlt">waters</span> are similar to those expected of the ammonia-oxidizing Group I Crenarchaeota, with predominance of crenarchaeol and abundant cyclic GDGTs; non-metric multidimensional analysis (NMDS) shows this pattern is associated with high nitrate concentrations. In contrast, limited culture evidence indicates <span class="hlt">marine</span> Group II Euryarchaeota may be capable of producing mainly caldarchaeol and some, but not all, of the ringed GDGTs and we suggest that these organisms, along with the Crenarchaeota, contribute to lipids in epipelagic <span class="hlt">marine</span> <span class="hlt">waters</span>. Calculated TEX 86 temperatures in mesopelagic samples (reported here and in published data sets) are always much warmer than measured in situ temperatures. We propose lipids used in the temperature proxy derive from both Euryarchaeaota</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.water.usgs.gov/ofr2004-1326/','USGSPUBS'); return false;" href="http://pubs.water.usgs.gov/ofr2004-1326/"><span>Atrazine concentrations in stream <span class="hlt">water</span> and streambed sediment <span class="hlt">pore</span> <span class="hlt">water</span> in the St. Joseph and Galien River basins, Michigan and Indiana, May 2001-September 2003</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Duris, Joseph W.; Reeves, Howard W.; Kiesler, James L.</p> <p>2005-01-01</p> <p>The U.S. Geological Survey (USGS) sampled multiple stream sites across the St. Joseph and Galien River Basins to detect and quantify the herbicide atrazine using a field enzyme-linked immunosorbent assay (ELISA) triazine test. In May 2001, July 2001, April 2002, August 2002, August 2003 and September 2003, composite samples were collected across streams at USGS streamflow-gaging stations. Concentrations and instantaneous loading for atrazine sampled in stream <span class="hlt">water</span> throughout the St. Joseph River and Galien River Basins in Michigan and Indiana ranged from nondetection (< 0.05 part per billion (ppb)) with an associated load less than 0.001 kilogram per day (kg/d) to 6 ppb and a maximum load of 10 kg/d. Atrazine concentrations were highest in May 2001 just after the planting season. The lowest concentration was found in April 2002 just before planting. Atrazine concentrations in streambed-sediment <span class="hlt">pore</span> <span class="hlt">water</span> were not spatially connected with atrazine concentrations in stream-<span class="hlt">water</span> samples. This study showed that atrazine concentrations were elevated from May to July in the St. Joseph and Galien River Basins. At many sites, concentrations exceeded the level that has been shown to feminize frog populations (0.2 ppb). There were 8 sites where concentrations exceeded 0.2 ppb atrazine in May 2001 and July 2001.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22960505','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22960505"><span>Estimating the toxicity of the weak base carbendazim to the earthworm (Eisenia fetida) using in situ <span class="hlt">pore</span> <span class="hlt">water</span> concentrations in different soils.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Kailin; Pan, Xiong; Han, Yuling; Tang, Feifan; Yu, Yunlong</p> <p>2012-11-01</p> <p>Both sorption by soil and uptake by organisms of ionizable organic pollutants depend on their speciation (i.e., neutral and ionized forms); thus, the bioavailability of ionizable organic pollutants is more complicated than that of neutral organic pollutants in soil. The toxicity of the weak base carbendazim to earthworms (Eisenia fetida) was estimated using Soxhlet extracted concentrations (C(SE)), an excess of <span class="hlt">water</span> extracted concentrations (C(EEW)), ex situ <span class="hlt">pore</span> <span class="hlt">water</span> concentrations (C(EPW)) and in situ <span class="hlt">pore</span> <span class="hlt">water</span> concentrations (C(IPW)) in different soils. The results indicated that the median lethal concentrations (LC50) calculated from C(SE) ranged from 2.32 to 34.0 mg kg(-1) in the five tested soils and the coefficient of variation (CV) of LC50s was 69.8%. When the LC50 was calculated from the C(EEW), C(EPW) and C(IPW), the variability of the LC50 gradually became smaller in these soils, with the CVs of LC50s being 58.1%, 50.6% and 38.6% (for C(EEW), C(EPW) and C(IPW), respectively). However, the LC50 based on C(IPW) in strongly acidic soil (where carbendazim partially exists as ionized form) was significantly lower than in other soils, and the values of the LC50 calculated from the in situ <span class="hlt">pore</span> <span class="hlt">water</span> concentrations were approximately equal. The results indicated that the in situ <span class="hlt">pore</span> <span class="hlt">water</span> concentration could be used to estimate the toxicity of carbendazim in different soils especially in those soils where carbendazim exists in the neutral form.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeoRL..42.2885O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeoRL..42.2885O"><span>Nitrous oxide and methane dynamics in a coral reef lagoon driven by <span class="hlt">pore</span> <span class="hlt">water</span> exchange: Insights from automated high-frequency observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>O'Reilly, Chiara; Santos, Isaac R.; Cyronak, Tyler; McMahon, Ashly; Maher, Damien T.</p> <p>2015-04-01</p> <p>Automated cavity ring down spectroscopy was used to make continuous measurements of dissolved methane, nitrous oxide, and carbon dioxide in a coral reef lagoon for 2 weeks (Heron Island, Great Barrier Reef). Radon (222Rn) was used to trace the influence of tidally driven <span class="hlt">pore</span> <span class="hlt">water</span> exchange on greenhouse gas dynamics. Clear tidal variation was observed for CH4, which correlated to 222Rn in lagoon <span class="hlt">waters</span>. N2O correlated to 222Rn during the day only, which appears to be a response to coupled nitrification-denitrification in oxic sediments, fueled by nitrate derived from bird guano. The lagoon was a net source of CH4 and N2O to the atmosphere and a sink for atmospheric CO2. The estimated <span class="hlt">pore</span> <span class="hlt">water</span>-derived CH4 and N2O fluxes were 3.2-fold and 24.0-fold greater than the fluxes to the atmosphere. Overall, <span class="hlt">pore</span> <span class="hlt">water</span> and/or groundwater exchange were the only important sources of CH4 and major controls of N2O in the coral reef lagoon.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15884378','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15884378"><span>Solid-phase microextraction measurement of parent and alkyl polycyclic aromatic hydrocarbons in milliliter sediment <span class="hlt">pore</span> <span class="hlt">water</span> samples and determination of K(DOC) values.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hawthorne, Steven B; Grabanski, Carol B; Miller, David J; Kreitinger, Joseph P</p> <p>2005-04-15</p> <p>The U.S. Environmental Protection Agency (EPA) narcosis model for benthic organisms in polycyclic aromatic hydrocarbon (PAH) contaminated sediments requires the measurement of 18 parent PAHs and 16 groups of alkyl PAHs ("34" PAHs) in <span class="hlt">pore</span> <span class="hlt">water</span> with desired detection limits as low as nanograms per liter. Solid-phase microextraction (SPME) with gas chromatographic/mass spectrometric (GC/ MS) analysis can achieve such detection limits in small <span class="hlt">water</span> samples, which greatly reduces the quantity of sediment <span class="hlt">pore</span> <span class="hlt">water</span> that has to be collected, shipped, stored, and prepared for analysis. Four sediments that ranged from urban background levels (50 mg/kg total "34" PAHs) to highly contaminated (10 000 mg/kg total PAHs) were used to develop SPME methodology for the "34" PAH determinations with only 1.5 mL of <span class="hlt">pore</span> <span class="hlt">water</span> per analysis. <span class="hlt">Pore</span> <span class="hlt">water</span> was obtained by centrifuging the wet sediment, and alum flocculation was used to remove colloids. Quantitative calibration was simplified by adding 15 two- to six-ring perdeuterated PAHs as internal standards to the <span class="hlt">water</span> calibration standards and the <span class="hlt">pore</span> <span class="hlt">water</span> samples. Response factors for SPME followed by GC/MS were measured for 22 alkyl PAHs compared to their parent PAHs and used to calibrate for the 18 groups of alkyl PAHs. Dissolved organic carbon (DOC) ranging from 4 to 27 mg/L had no measurable effect on the freely dissolved concentrations of two- and three-ring PAHs. In contrast, 5-80% of the total dissolved four- to six-ring PAHs were associated with the DOC rather than being freely dissolved, corresponding to DOC/<span class="hlt">water</span> partitioning coefficients (K(DOC)) with log K(DOC) values ranging from 4.1 (for fluoranthene) to 5.6 (for benzo[ghi]perylene). However, DOC-associated versus freely dissolved PAHs had no significant effect on the total "34" PAH concentrations or the sum of the "toxic units" (calculated bythe EPA protocol), since virtually all (86-99%) of the dissolved PAH concentrations and toxic units were contributed by two</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2974642','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2974642"><span>Distribution Analysis of Hydrogenases in Surface <span class="hlt">Waters</span> of <span class="hlt">Marine</span> and Freshwater Environments</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Barz, Martin; Beimgraben, Christian; Staller, Torsten; Germer, Frauke; Opitz, Friederike; Marquardt, Claudia; Schwarz, Christoph; Gutekunst, Kirstin; Vanselow, Klaus Heinrich; Schmitz, Ruth; LaRoche, Julie; Schulz, Rüdiger; Appel, Jens</p> <p>2010-01-01</p> <p>Background Surface <span class="hlt">waters</span> of aquatic environments have been shown to both evolve and consume hydrogen and the ocean is estimated to be the principal natural source. In some <span class="hlt">marine</span> habitats, H2 evolution and uptake are clearly due to biological activity, while contributions of abiotic sources must be considered in others. Until now the only known biological process involved in H2 metabolism in <span class="hlt">marine</span> environments is nitrogen fixation. Principal Findings We analyzed <span class="hlt">marine</span> and freshwater environments for the presence and distribution of genes of all known hydrogenases, the enzymes involved in biological hydrogen turnover. The total genomes and the available <span class="hlt">marine</span> metagenome datasets were searched for hydrogenase sequences. Furthermore, we isolated DNA from samples from the North Atlantic, Mediterranean Sea, North Sea, Baltic Sea, and two fresh <span class="hlt">water</span> lakes and amplified and sequenced part of the gene encoding the bidirectional NAD(P)-linked hydrogenase. In 21% of all <span class="hlt">marine</span> heterotrophic bacterial genomes from surface <span class="hlt">waters</span>, one or several hydrogenase genes were found, with the membrane-bound H2 uptake hydrogenase being the most widespread. A clear bias of hydrogenases to environments with terrestrial influence was found. This is exemplified by the cyanobacterial bidirectional NAD(P)-linked hydrogenase that was found in freshwater and coastal areas but not in the open ocean. Significance This study shows that hydrogenases are surprisingly abundant in <span class="hlt">marine</span> environments. Due to its ecological distribution the primary function of the bidirectional NAD(P)-linked hydrogenase seems to be fermentative hydrogen evolution. Moreover, our data suggests that <span class="hlt">marine</span> surface <span class="hlt">waters</span> could be an interesting source of oxygen-resistant uptake hydrogenases. The respective genes occur in coastal as well as open ocean habitats and we presume that they are used as additional energy scavenging devices in otherwise nutrient limited environments. The membrane-bound H2-evolving</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28306899','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28306899"><span>[On the colonization of brackish <span class="hlt">water</span> by <span class="hlt">marine</span> animals of different ecological origin].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Remmert, Hermann</p> <p>1968-11-01</p> <p>Since animals of the <span class="hlt">marine</span> littoral and supralitoral zones tolerate greater salinity-fluctuations than those of deep <span class="hlt">water</span> layers they are far better adapted to colonize estuaries and brackish <span class="hlt">waters</span>.This is why there live only few animals from the seabottom in brackish <span class="hlt">water</span> even if it is very deep. Only animals from the littoral invade <span class="hlt">water</span> with low or fluctuationg salinities.Those which are not restricted to surface regions (by their food - many depend on green plants) extend their range in brackish <span class="hlt">waters</span> into deep layers since there is almost no competition.Therefore the bottom communities of the sea differ very much from the bottom communities of deep brackish <span class="hlt">waters</span>.The extension of the range of <span class="hlt">marine</span> littoral animals in deep brackish basins ("Brackwassersubmergenz") therefore is characteristic for deep brackish-<span class="hlt">water</span>-zones and no special case of the Baltic Sea.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016E%26ES...43a2058N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016E%26ES...43a2058N"><span>Changes in composition and <span class="hlt">pore</span> space of sand rocks in the oil <span class="hlt">water</span> contact zone (section YU1 3-4, Klyuchevskaya area, Tomsk region)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nedolivko, N.; Perevertailo, T.; Pavlovec, T.</p> <p>2016-09-01</p> <p>The article provides an analysis of specific features in changes of rocks in the oil <span class="hlt">water</span> contact zone. The object of study is the formation YU1 3-4 (J3o1) of Klyuchevskaya oil deposit (West Siberian oil-gas province, Tomsk region). The research data allow the authors to determine vertical zoning of the surface structure and identify the following zones: oil saturation (weak alteration), bitumen-content dissolution, non-bitumen-content dissolution, cementation, including rocks not affected by hydrocarbon deposit. The rocks under investigation are characterized by different changes in composition, <span class="hlt">pore</span> space, as well as reservoir filtration and volumetric parameters. Detection of irregularity in distribution of void- <span class="hlt">pore</span> space in oil-<span class="hlt">water</span> contact zones is of great practical importance. It helps to avoid the errors in differential pressure drawdown and explain the origin of low-resistivity collectors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title33-vol3/pdf/CFR-2014-title33-vol3-sec334-420.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title33-vol3/pdf/CFR-2014-title33-vol3-sec334-420.pdf"><span>33 CFR 334.420 - Pamlico Sound and adjacent <span class="hlt">waters</span>, N.C.; danger zones for <span class="hlt">Marine</span> Corps operations.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-07-01</p> <p>..., N.C.; danger zones for <span class="hlt">Marine</span> Corps operations. 334.420 Section 334.420 Navigation and Navigable... REGULATIONS § 334.420 Pamlico Sound and adjacent <span class="hlt">waters</span>, N.C.; danger zones for <span class="hlt">Marine</span> Corps operations. (a... date. <span class="hlt">Marine</span> Corps Air Station Cherry Point will have a call-in number for public use to...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14...37S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14...37S"><span>Transport of viruses in <span class="hlt">water</span> saturated columns packed with sand: Effect of <span class="hlt">pore</span> <span class="hlt">water</span> velocity, sand grain size, and suspended colloids</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Syngouna, V.; Chrysikopoulos, C.</p> <p>2012-04-01</p> <p>In this study, the attachment behavior of model viruses (bacteriophages MS2 and ΦX174) onto quartz sand of three different grain sizes for various <span class="hlt">pore</span> <span class="hlt">water</span> velocities with and without the presence of suspended model clay colloids (kaolinite: KGa-1b and montmorillonite: STx-1b) were evaluated. No obvious relationships between virus mass recoveries and <span class="hlt">water</span> velocity or grain size could be established from the experimental results. The observed mean dispersivity values for each sand grain size were higher for MS2 than ΦX174. The interaction of viruses with KGa-1b and STx-1b was investigated with batch as well as virus-clay cotransport experiments. The batch experimental data suggested that virus attachment onto KGa-1b and STx-1b is adequately described by the Freundlich isotherm equation. The presence of suspended colloids was shown to significantly influence virus deposition. In both batch and co-transport experiments, MS2 and ΦX174 were attached in greater amounts onto KGa-1b than STx-1b with MS2 having greater affinity than ΦX174 for both clays. Furthermore, extended-DLVO interaction energy calculations explained that the attachment of viruses onto model clay colloids was primarily caused by hydrophobic interaction. The theoretical and experimental results of this study were found to be in good agreement with previous findings.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2006/5134/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2006/5134/"><span><span class="hlt">Pore-Water</span> Quality in the Clay-Silt Confining Units of the Lower Miocene Kirkwood Formation and Hypothetical Effects on <span class="hlt">Water</span> Quality in the Atlantic City 800-Foot Sand, Northeastern Cape May County, New Jersey, 2001</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Szabo, Zoltan; Keller, Elizabeth A.; Defawe, Rose M.</p> <p>2006-01-01</p> <p><span class="hlt">Pore</span> <span class="hlt">water</span> was extracted from clay-silt core samples collected from a borehole at Ocean View, west of Sea Isle City, in northeastern Cape May County, New Jersey. The borehole intersects the lower Miocene Kirkwood Formation, which includes a thick sand and gravel unit between two clay-silt units. The sand and gravel unit forms a major confined aquifer in the region, known as the Atlantic City 800-foot sand, the major source of potable <span class="hlt">water</span> along the Atlantic Coast of southern New Jersey. The <span class="hlt">pore</span> <span class="hlt">water</span> from the core is of interest because the borehole intersects the aquifer in an area where the ground <span class="hlt">water</span> is sodium-rich and sulfidic. Locally in the aquifer in central and southern Cape May County, sodium concentrations are near the New Jersey secondary drinking-<span class="hlt">water</span> standard of 50 mg/L (milligrams per liter), and typically are greater than 30 mg/L, but chloride and sulfate do not approach their respective secondary drinking-<span class="hlt">water</span> standards except in southernmost Cape May County. <span class="hlt">Pore</span> <span class="hlt">waters</span> from the confining units are suspected to be a source of sodium, sulfur, and chloride to the aquifer. Constituent concentrations in filtered <span class="hlt">pore-water</span> samples were determined using the inductively coupled plasma-mass spectrometry analytical technique to facilitate the determination of low-level concentrations of many trace constituents. Calcium-sodium-sulfate-bicarbonate, calcium-chloride-sulfate, calcium-sulfate, and sodium-sulfate-chloride-bicarbonate type <span class="hlt">waters</span> characterize samples from the deepest part of the confining unit directly overlying the aquifer (termed the 'lower' confining unit). A sodium-chloride-sulfate type <span class="hlt">water</span> is dominant in the composite confining unit below the aquifer. Sodium, chloride, and sulfate became increasingly dominant with depth. <span class="hlt">Pore</span> <span class="hlt">water</span> from the deepest sample recovered (1,390 ft (feet) below land surface) was brackish, with concentrations of sodium, chloride, and sulfate of 5,930, 8,400, and 5,070 mg/L, respectively. <span class="hlt">Pore-water</span> samples</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2350241','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2350241"><span>GATED <span class="hlt">PORES</span> IN THE FERRITIN PROTEIN NANOCAGE</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Theil, Elizabeth C.; Liu, Xiaofeng S.; Tosha, Takehiko</p> <p>2008-01-01</p> <p>Synopsis and pictogram: Gated <span class="hlt">pores</span> in the ferritin family of protein nanocages, illustrated in the pictogram, control transfer of ferrous iron into and out of the cages by regulating contact between hydrated ferric oxide mineral inside the protein cage, and reductants such as FMNH2 on the outside. The structural and functional homology between the gated ion channel proteins in inaccessible membranes and gated ferritin <span class="hlt">pores</span> in the stable, <span class="hlt">water</span> soluble nanoprotein, make studies of ferritin <span class="hlt">pores</span> models for gated <span class="hlt">pores</span> in many ion channel proteins. Properties of ferritin gated <span class="hlt">pores</span>, which control rates of FMNH2 reduction of ferric iron in hydrated oxide minerals inside the protein nanocage, are discussed in terms of the conserved <span class="hlt">pore</span> gate residues (arginine 72-apspartate 122 and leucine 110-leucine 134), of <span class="hlt">pore</span> sensitivity to heat at temperatures 30 °C below that of the nanocage itself, and of <span class="hlt">pore</span> sensitivity to physiological changes in urea (1–10 mM). Conditions which alter ferritin <span class="hlt">pore</span> structure/function in solution, coupled with the high evolutionary conservation of the <span class="hlt">pore</span> gates, suggest the presence of molecular regulators in vivo that recognize the <span class="hlt">pore</span> gates and hold them either closed or open, depending on biological iron need. The apparent homology between ferrous ion transport through gated <span class="hlt">pores</span> in the ferritin nanocage and ion transport through gated <span class="hlt">pores</span> in ion channel proteins embedded in cell membranes, make studies of <span class="hlt">water</span> soluble ferritin and the <span class="hlt">pore</span> gating folding/unfolding a useful model for other gated <span class="hlt">pores</span>. PMID:19262678</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMOS51D1285H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMOS51D1285H"><span>Use of <span class="hlt">Pore</span> <span class="hlt">water</span> Rn and Ra Profiles to Evaluate the Nature of Flow through Permeable Coastal Sands in Huntington Beach, Southern California</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hammond, D. E.; Colbert, S. L.; Talsky, H.; Schwartz, R. J.</p> <p>2008-12-01</p> <p>Submarine Groundwater Discharge (SGD), as commonly defined, can represent (1) <span class="hlt">water</span> recharged above sea level, or (2) <span class="hlt">water</span> that is circulated locally through permeable sediments by pressure gradients generated by flow over rough topography, by wave activity, and by physical pumping of irrigating macrofauna. Under some circumstances, rapid increases in <span class="hlt">water</span> column density over time could also drive episodes of <span class="hlt">pore</span> fluid circulation. Budgets for radium isotopes in the <span class="hlt">water</span> column have been used to evaluate SGD in a number of recent studies, and used to calculate fluxes of nutrients due to SGD. However, because the scale distances for nutrients may differ from those of the Ra isotopes, it is important to constrain whether SGD calculated from near-shore <span class="hlt">water</span> column Ra budgets represents local circulation of overlying <span class="hlt">water</span> through sediments, or regional flow driven by recharge above sea level. This also can define whether nutrient fluxes are driven by re-mineralization of biogenic material formed in the overlying <span class="hlt">water</span>, or by transport from adjacent land areas. We have measured profiles of Rn-222 and Ra isotopes (223,224, 228) in <span class="hlt">pore</span> <span class="hlt">waters</span> of permeable sediments offshore from Huntington Beach on multiple occasions, working at the shoreline and at <span class="hlt">water</span> depths of 5 to 15 m. By also determining the rate at which these isotopes emanate from solid phases and the adsorption constant for Ra on solid phases, we can evaluate the nature of SGD circulation in this system. Results indicate that nearly all of the SGD is due to local recirculation of overlying <span class="hlt">water</span>, with macrofaunal irrigation probably driving most of the flow. Ra-228 profiles, coupled with <span class="hlt">water</span> column budgets, can be used to put constraints on regional vertical flow.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1475027','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1475027"><span>Levels of toxic metals in <span class="hlt">marine</span> organisms collected from Southern California coastal <span class="hlt">waters</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Fowler, B A; Fay, R C; Walter, R L; Willis, R D; Gutknecht, W F</p> <p>1975-01-01</p> <p>Emission of toxic trace metals into southern California coastal <span class="hlt">waters</span> has resulted in the extensive accumulation of the elements within <span class="hlt">marine</span> sediments. The current study was undertaken to evaluate concentrations of trace metals in bottom-dwelling <span class="hlt">marine</span> fauna collected from two sampling areas. Analyses carried out on muscle samples of the dover sole (Microstomus pacificus) and the crab (Cancer anthonyi) by proton-induced x-ray emission analysis showed considerable concentrations of arsenic and selenium. Samples of gonads, digestive gland, and muscle from the crab Mursia gaudichaudii analyzed by atomic absorption spectroscopy showed elemental concentrations in muscle similar to the crab Cancer anthonyi and much higher metal levels in gonad and digestive gland. These findings suggest the need for further studies concerning the relationship between emission of metals into the <span class="hlt">marine</span> environment and their abundance in <span class="hlt">marine</span> fauna. PMID:1227863</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016E%26ES...39a2031Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016E%26ES...39a2031Z"><span><span class="hlt">Pore</span> pressure propagation in a permeable thin-layer coal seam based on a dual porosity model: A case of risk prediction of <span class="hlt">water</span> inrush in coalmines</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhu, B.; Gao, F.; Yang, J. W.; Zhou, G. Q.</p> <p>2016-08-01</p> <p>Thin-layer coal seams, a type of filling coal rock body, are considered aquifer systems made up of dual porosity medium with immediate floor. A numerical simulation for the <span class="hlt">pore</span> pressure propagation along a thin-layer coal seam was carried out for the case of the Zhaogezhuang coalmine in China. By valuing the permeability (Kf ) of the thin-layer coal seam, <span class="hlt">pore</span> pressure variation with time was simulated and compared to the analytical solutions of a dual porosity model (DPM). The main conclusions were drawn as follow: (1) Seepage in the thin-layer coal seam was predominant in the whole process, and the distance of seepage was lengthened and the <span class="hlt">pore</span> pressure decreased with increased Kf , (2) A series of simulated hydraulic graphs demonstrated that the <span class="hlt">pore</span> pressure characteristics of peak-occurring and time-lag effects agreed with the analytical solutions of DPM; (3) By adjusting the parameters of DPM, two results of analytical solutions and numerical solutions fit well, particularly in the thin-layer coal seam, (4) The power law relationship between the peak-values and lag time of <span class="hlt">pore</span> pressure were derived statistically under consideration of the Kf parameter in the range of 10-8 to 10-10 m2/pa-s orders, and it was reasonable that the Kf of the thin-layer coal seam was in the range of 10-8 m2/pa-s orders. The results were significantly helpful in decision-making for mining <span class="hlt">water</span> prevention and prediction in practice.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009JChPh.130l4518J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009JChPh.130l4518J"><span>Origin of the enthalpy features of <span class="hlt">water</span> in 1.8 nm <span class="hlt">pores</span> of MCM-41 and the large Cp increase at 210 K</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Johari, G. P.</p> <p>2009-03-01</p> <p>It is shown that exothermic and endothermic features of dHm/dt observed on heating rapidly precooled and slowly precooled states of <span class="hlt">water</span> in 1.8 nm <span class="hlt">pores</span> of MCM-41 and the unusually large increase in the specific heat in the 210-230 K range [M. Oguni, Y. Kanke, S. Namba, and AIP Conf, Proc. 982, 34 (2008)] are inconsistent with kinetic unfreezing of a disordered solid, or glass softening. The exotherm is attributable to the melt's gradual conversion to distorted icelike structures and the endotherm to the reverse process until their fractional amounts reach a reversible equilibrium on heating. The large increase in Cp,m with T is attributed to the latent heat, similar to that seen on premelting of fine grain crystals. The available calorimetric data on freezing and melting and the <span class="hlt">pore</span>-size dependence of the features support this interpretation. The findings also put into question a conclusion from neutron scattering studies that in 1.8 nm <span class="hlt">pores</span> <span class="hlt">water</span> undergoes a structural and kinetic transition at ˜225 K while remaining a liquid.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19730050862&hterms=Water+pollution&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DWater%2Bpollution','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19730050862&hterms=Water+pollution&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DWater%2Bpollution"><span>Remote sensing of chlorophyll and temperature in <span class="hlt">marine</span> and fresh <span class="hlt">waters</span>.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Arvesen, J. C.; Millard, J. P.; Weaver, E. C.</p> <p>1973-01-01</p> <p>An airborne differential radiometer was demonstrated to be a sensitive, real-time detector of surface chlorophyll content in <span class="hlt">water</span> bodies. The instrument continuously measures the difference in radiance between two wavelength bands, one centered near the maximum of the blue chlorophyll a absorption region and the other at a reference wavelength outside this region. Flights were made over fresh <span class="hlt">water</span> lakes, <span class="hlt">marine</span> <span class="hlt">waters</span>, and an estuary, and the results were compared with 'ground truth' measurements of chlorophyll concentration. A correlation between output signal of the differential radiometer and the chlorophyll concentration was obtained. Examples of flight data are illustrated. Simultaneous airborne measurements of chlorophyll content and <span class="hlt">water</span> temperature revealed that variations in chlorophyll are often associated with changes in temperature. Thus, simultaneous sensing of chlorophyll and temperature provides useful information for studies of <span class="hlt">marine</span> food production, <span class="hlt">water</span> pollution, and physical processes such as upwelling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/965182','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/965182"><span>Post-Remediation Biomonitoring of Pesticides in <span class="hlt">Marine</span> <span class="hlt">Waters</span> Near the United Heckathorn Site, Richmond, California</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Antrim, Liam D.; Kohn, Nancy P.</p> <p>2000-09-05</p> <p><span class="hlt">Marine</span> sediment remediation at the United Heckathorn Superfund Site was completed in April 1997. <span class="hlt">Water</span> and mussel tissues were sampled in January 1998 from four stations near Lauritzen Canal in Richmond, California, for the first post-remediation monitoring of <span class="hlt">marine</span> areas near the United Heckathorn Site. Dieldrin and DDT were analyzed in <span class="hlt">water</span> samples, tissue samples from resident mussels, and tissue samples from transplanted mussels deployed for 4 months. Concentrations of dieldrin and total DDT in <span class="hlt">water</span> and total DDT in tissue were compared to pre-remediation data available from the California State Mussel Watch program (tissues) and the Ecological Risk Assessment for the United Heckathorn Superfund Site (tissues and <span class="hlt">water</span>). Biomonitoring results indicated that pesticides were still bioavailable in the <span class="hlt">water</span> column, and have not been reduced from pre-remediation levels. Annual biomonitoring will continue to assess the effectiveness of remedial actions at the United Heckathorn Site.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26961471','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26961471"><span>Impact of Stormwater Discharges on <span class="hlt">Water</span> Quality in Coastal <span class="hlt">Marine</span> Protected Areas.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schiff, Kenneth; Luk, Brenda; Gregorio, Dominic</p> <p>2015-09-01</p> <p><span class="hlt">Marine</span> protected areas worldwide limit harvest to protect sensitive fisheries, but rarely do they address <span class="hlt">water</span> quality goals that may have equally demonstrable impacts. California has over 500 coastal shoreline miles of <span class="hlt">marine</span> protected areas designated as Areas of Special Biological Significance (ASBS), but receives untreated wet weather runoff discharges from over 1600 storm drain outfalls. The goal of this study was to assess the extent and magnitude of <span class="hlt">water</span> quality impacts in ASBS following storm events. A stratified probabilistic design was used for sampling receiving <span class="hlt">water</span> shorelines near (discharge) and far (non-discharge) from storm drain outfalls. In general, reasonably good <span class="hlt">water</span> quality exists in California's ASBS following storm events. Many of the target analytes measured did not exceed <span class="hlt">water</span> quality standards. The post-storm concentrations of most constituents in discharge and non-discharge strata of ASBS were similar. The three potentially problematic parameters identified were total PAH, chromium, and copper.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9240E..1EZ','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9240E..1EZ"><span>Study of the selection of indicator parameters in <span class="hlt">marine</span> <span class="hlt">water</span> quality evaluation and the evaluation methodology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Ying; Pan, Delu; Wang, Difeng; Fu, Dongyang</p> <p>2014-10-01</p> <p>In order to obtain the indicator types which must be introduced in <span class="hlt">marine</span> <span class="hlt">water</span> quality evaluation as well as the suitable evaluation methodology, GB3097-1997 National <span class="hlt">Marine</span> <span class="hlt">Water</span> Quality Standards is, in the first place, analyzed to establish a hypothetical sample which is consisting of 2000 stances, each stance containing the information of 21 indicators. And then a stepwise discriminant method is utilized to filter the 21 indicators in accordance with their <span class="hlt">water</span> quality classification discriminant abilities. And finally, 6 indicators with significant discriminant ability, biochemical oxygen demand(BOD5), oil type(Oil), total phosphorus(P), cadmium(Cd), cyanide(HH) and chemical oxygen demand(COD), are selected and the <span class="hlt">water</span> quality evaluation chart of the corresponding six indicators is also established. Theoretically, the <span class="hlt">water</span> quality indicator types and the suitable evaluation methodology, which must be introduced when the <span class="hlt">water</span> quality evaluation is done in all the <span class="hlt">waters</span> under the jurisdiction of China, are discussed in this paper, providing theoretical basis for the subsequent <span class="hlt">marine</span> <span class="hlt">water</span> quality evaluation based on field observation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6281743','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6281743"><span>Interactions of aquaculture, <span class="hlt">marine</span> coastal ecosystems, and near-shore <span class="hlt">waters</span>: A bibliography. Bibliographies and literature of agriculture (Final)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hanfman, D.T.; Coleman, D.E.; Tibbitt, S.J.</p> <p>1991-01-01</p> <p>The bibliography contains selected literature citations on the interactions of aquaculture and <span class="hlt">marine</span> coastal ecosystems. The focus is on aquaculture effluents and their impact on <span class="hlt">marine</span> coastal ecosystems and waterways as well as the impact of pollutants on aquaculture development. Factors affecting these issues include domestic and industrial wastes, thermal discharges, acid rain, heavy metals, oil spills, and microbial contamination of <span class="hlt">marine</span> <span class="hlt">waters</span> and aquatic species. Coastal zone management, environmenal impact of aquaculture, and <span class="hlt">water</span> quality issues are also included in the bibliography.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28186740','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28186740"><span>Effect of Low Energy Waves on the Accumulation and Transport of Fecal Indicator Bacteria in Sand and <span class="hlt">Pore</span> <span class="hlt">Water</span> at Freshwater Beaches.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wu, Ming Zhi; O'Carroll, Denis M; Vogel, Laura J; Robinson, Clare E</p> <p>2017-03-07</p> <p>Elevated fecal indicator bacteria (FIB) in beach sand and <span class="hlt">pore</span> <span class="hlt">water</span> represent an important nonpoint source of contamination to surface <span class="hlt">waters</span>. This study examines the physical processes governing the accumulation and distribution of FIB in a beach aquifer. Field data indicate E. coli and enterococci can be transported 1 and 2 m, respectively, below the <span class="hlt">water</span> table. Data were used to calibrate a numerical model whereby FIB are delivered to a beach aquifer by wave-induced infiltration across the beach face. Simulations indicate FIB rapidly accumulate in a beach aquifer with FIB primarily associated with sand rather than freely residing in the <span class="hlt">pore</span> <span class="hlt">water</span>. Simulated transport of E. coli in a beach aquifer is complex and does not correlate with conservative tracer transport. Beaches with higher wave-induced infiltration rate and vertical infiltration velocity (i.e., beaches with higher beach slope and wave height, and lower terrestrial groundwater discharge) had greater E. coli accumulation and E. coli was transported deeper below the beach face. For certain beach conditions, the amount of FIB accumulated in sand over 5-6 days was found to be sufficient to trigger a beach advisory if eroded to surface <span class="hlt">water</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title36-vol1/pdf/CFR-2012-title36-vol1-sec13-1130.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title36-vol1/pdf/CFR-2012-title36-vol1-sec13-1130.pdf"><span>36 CFR 13.1130 - Is commercial fishing authorized in the <span class="hlt">marine</span> <span class="hlt">waters</span> of Glacier Bay National Park?</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-07-01</p> <p>... authorized in the <span class="hlt">marine</span> <span class="hlt">waters</span> of Glacier Bay National Park? 13.1130 Section 13.1130 Parks, Forests, and... Special Regulations-Glacier Bay National Park and Preserve Commercial Fishing § 13.1130 Is commercial fishing authorized in the <span class="hlt">marine</span> <span class="hlt">waters</span> of Glacier Bay National Park? Yes—Commercial fishing is...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title36-vol1/pdf/CFR-2014-title36-vol1-sec13-1130.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title36-vol1/pdf/CFR-2014-title36-vol1-sec13-1130.pdf"><span>36 CFR 13.1130 - Is commercial fishing authorized in the <span class="hlt">marine</span> <span class="hlt">waters</span> of Glacier Bay National Park?</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-07-01</p> <p>... authorized in the <span class="hlt">marine</span> <span class="hlt">waters</span> of Glacier Bay National Park? 13.1130 Section 13.1130 Parks, Forests, and... Special Regulations-Glacier Bay National Park and Preserve Commercial Fishing § 13.1130 Is commercial fishing authorized in the <span class="hlt">marine</span> <span class="hlt">waters</span> of Glacier Bay National Park? Yes—Commercial fishing is...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title36-vol1/pdf/CFR-2013-title36-vol1-sec13-1130.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title36-vol1/pdf/CFR-2013-title36-vol1-sec13-1130.pdf"><span>36 CFR 13.1130 - Is commercial fishing authorized in the <span class="hlt">marine</span> <span class="hlt">waters</span> of Glacier Bay National Park?</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-07-01</p> <p>... authorized in the <span class="hlt">marine</span> <span class="hlt">waters</span> of Glacier Bay National Park? 13.1130 Section 13.1130 Parks, Forests, and... Special Regulations-Glacier Bay National Park and Preserve Commercial Fishing § 13.1130 Is commercial fishing authorized in the <span class="hlt">marine</span> <span class="hlt">waters</span> of Glacier Bay National Park? Yes—Commercial fishing is...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4431714','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4431714"><span>Decoding Size Distribution Patterns in <span class="hlt">Marine</span> and Transitional <span class="hlt">Water</span> Phytoplankton: From Community to Species Level</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Roselli, Leonilde; Basset, Alberto</p> <p>2015-01-01</p> <p>Understanding the mechanisms of phytoplankton community assembly is a fundamental issue of aquatic ecology. Here, we use field data from transitional (e.g. coastal lagoons) and coastal <span class="hlt">water</span> environments to decode patterns of phytoplankton size distribution into organization and adaptive mechanisms. Transitional <span class="hlt">waters</span> are characterized by higher resource availability and shallower well-mixed <span class="hlt">water</span> column than coastal <span class="hlt">marine</span> environments. Differences in physico-chemical regime between the two environments have been hypothesized to exert contrasting selective pressures on phytoplankton cell morphology (size and shape). We tested the hypothesis focusing on resource availability (nutrients and light) and mixed layer depth as ecological axes that define ecological niches of phytoplankton. We report fundamental differences in size distributions of <span class="hlt">marine</span> and freshwater diatoms, with transitional <span class="hlt">water</span> phytoplankton significantly smaller and with higher surface to volume ratio than <span class="hlt">marine</span> species. Here, we hypothesize that mixing condition affecting size-dependent sinking may drive phytoplankton size and shape distributions. The interplay between shallow mixed layer depth and frequent and complete mixing of transitional <span class="hlt">waters</span> may likely increase the competitive advantage of small phytoplankton limiting large cell fitness. The nutrient regime appears to explain the size distribution within both <span class="hlt">marine</span> and transitional <span class="hlt">water</span> environments, while it seem does not explain the pattern observed across the two environments. In addition, difference in light availability across the two environments appear do not explain the occurrence of asymmetric size distribution at each hierarchical level. We hypothesize that such competitive equilibria and adaptive strategies in resource exploitation may drive by organism’s behavior which exploring patch resources in transitional and <span class="hlt">marine</span> phytoplankton communities. PMID:25974052</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25974052','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25974052"><span>Decoding size distribution patterns in <span class="hlt">marine</span> and transitional <span class="hlt">water</span> phytoplankton: from community to species level.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Roselli, Leonilde; Basset, Alberto</p> <p>2015-01-01</p> <p>Understanding the mechanisms of phytoplankton community assembly is a fundamental issue of aquatic ecology. Here, we use field data from transitional (e.g. coastal lagoons) and coastal <span class="hlt">water</span> environments to decode patterns of phytoplankton size distribution into organization and adaptive mechanisms. Transitional <span class="hlt">waters</span> are characterized by higher resource availability and shallower well-mixed <span class="hlt">water</span> column than coastal <span class="hlt">marine</span> environments. Differences in physico-chemical regime between the two environments have been hypothesized to exert contrasting selective pressures on phytoplankton cell morphology (size and shape). We tested the hypothesis focusing on resource availability (nutrients and light) and mixed layer depth as ecological axes that define ecological niches of phytoplankton. We report fundamental differences in size distributions of <span class="hlt">marine</span> and freshwater diatoms, with transitional <span class="hlt">water</span> phytoplankton significantly smaller and with higher surface to volume ratio than <span class="hlt">marine</span> species. Here, we hypothesize that mixing condition affecting size-dependent sinking may drive phytoplankton size and shape distributions. The interplay between shallow mixed layer depth and frequent and complete mixing of transitional <span class="hlt">waters</span> may likely increase the competitive advantage of small phytoplankton limiting large cell fitness. The nutrient regime appears to explain the size distribution within both <span class="hlt">marine</span> and transitional <span class="hlt">water</span> environments, while it seem does not explain the pattern observed across the two environments. In addition, difference in light availability across the two environments appear do not explain the occurrence of asymmetric size distribution at each hierarchical level. We hypothesize that such competitive equilibria and adaptive strategies in resource exploitation may drive by organism's behavior which exploring patch resources in transitional and <span class="hlt">marine</span> phytoplankton communities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/7973603','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/7973603"><span>Environmental contamination and <span class="hlt">marine</span> mammals in coastal <span class="hlt">waters</span> from Argentina: an overview.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Marcovecchio, J E; Gerpe, M S; Bastida, R O; Rodríguez, D H; Morón, S G</p> <p>1994-09-16</p> <p>Environmental contamination become an increasing global problem. Different scientific strategies have been developed in order to assess the impact of pollutants on <span class="hlt">marine</span> ecosystems. The distribution of toxic contaminants in tissues of different <span class="hlt">marine</span> mammal species--both cetaceans and pinnipeds--has been studied in many ecosystems, as well as several related ecological processes, like pollutant accumulation or transfer through the food web. A research program directed towards evaluating the occurrence of pollutants in <span class="hlt">marine</span> mammals from the coastal <span class="hlt">waters</span> of Argentina (southwestern Atlantic Ocean) has been developed since 1985, and includes the study of heavy metal contents in stranded or incidentally caught animals. The <span class="hlt">marine</span> mammal species studied during this period were: the seals Otaria flavescens and Arctocephalus australis, and small cetaceans Tursiops gephyreus, Pontoporia blainvillei, Kogia breviceps and Ziphius cavirostris. In most of the cases, high contents of heavy metals (total mercury, cadmium, zinc, and copper) have been recorded. Moreover, liver showed the maximum capability for accumulation of heavy metals in all studied species. The biological and ecological characteristics of each species of the above-mentioned <span class="hlt">marine</span> mammals (feeding habits, age, migratory pathways, or sex) contributed to the understanding of the metal sources. Considering the results as obtained during the study period it can be assumed that: (1) The global distribution of toxic contaminants also affects the southwestern Atlantic Ocean ecosystems, and (2) <span class="hlt">Marine</span> mammals could be appropriate bioindicator species in order to assess this kind of environmental problem.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1219871','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1219871"><span>U.S. <span class="hlt">Marine</span> Corps Stand at Forefront of Energy and <span class="hlt">Water</span> Savings</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p></p> <p>2012-12-01</p> <p>Located in the heart of South Carolina, the U.S. <span class="hlt">Marine</span> Corps Air Station (MCAS) Beaufort is among the military’s most important installations. Located on 6,900 acres 70 miles southwest of Charleston, the installation has established an energy- and <span class="hlt">water</span>-saving culture that explores and implements new strategies and management approaches aimed at surpassing presidential mandates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17794007','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17794007"><span>Barium in southern california coastal <span class="hlt">waters</span>: a potential indicator of <span class="hlt">marine</span> drilling contamination.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chow, T J</p> <p>1976-07-02</p> <p>The present barium content of Southern California coastal <span class="hlt">waters</span> was determined to be 11 to 22 micrograms per kilogram of seawater. These values may be used as base-line concentrations to monitor <span class="hlt">marine</span> contamination during future off-shore oil and gas explorations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17553708','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17553708"><span>Bridging the Rubicon: phylogenetic analysis reveals repeated colonizations of <span class="hlt">marine</span> and fresh <span class="hlt">waters</span> by thalassiosiroid diatoms.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Alverson, Andrew J; Jansen, Robert K; Theriot, Edward C</p> <p>2007-10-01</p> <p>Salinity imposes a significant barrier to the distribution of many organisms, including diatoms. Diatoms are ancestrally <span class="hlt">marine</span>, and the number of times they have independently colonized fresh <span class="hlt">waters</span> and the physiological adaptations that facilitated these transitions remain outstanding questions in diatom evolution. The colonization of fresh <span class="hlt">waters</span> by diatoms has been compared to "crossing the Rubicon," implying that successful colonization events are rare, irreversible, and lead to substantial species diversification. To test these hypotheses, we reconstructed the phylogeny of Thalassiosirales, a diatom lineage with high diversity in both <span class="hlt">marine</span> and fresh <span class="hlt">waters</span>. We collected approximately 5.3kb of DNA sequence data from the nuclear (SSU and partial LSU rDNA) and chloroplast genomes (psbC and rbcL) and reconstructed the phylogeny using parsimony and Bayesian methods. Alternative topology tests strongly reject all previous colonization hypotheses, including monophyly of the predominantly freshwater Stephanodiscaceae. Results showed at least three independent colonizations of fresh <span class="hlt">waters</span>, and whereas previous accounts of freshwater-to-<span class="hlt">marine</span> transitions have been discounted, these results provide compelling evidence for as many as three independent re-colonizations of the <span class="hlt">marine</span> habitat, two of which led to speciation events. This study adds valuable phylogenetic context to previous debate about the nature of the salinity barrier in diatoms and provides compelling evidence that, at least for Thalassiosirales, the salinity barrier might be less formidable than previously thought.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=191163&keyword=Molybdenum&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=89768401&CFTOKEN=73120354','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=191163&keyword=Molybdenum&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=89768401&CFTOKEN=73120354"><span>Molybdenum Accumulation in <span class="hlt">Marine</span> Sediments as an Indicator of Hypoxic <span class="hlt">Water</span> Conditions (NACAETAC)</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Direct monitoring of hypoxic <span class="hlt">water</span> column conditions over large spatial and temporal extents is difficult due to the substantial logistical and financial investment required. Recent studies have indicated that concentrations of molybdenum (Mo) in <span class="hlt">marine</span> sediments may serve as a u...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015LPICo1843.8018D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015LPICo1843.8018D"><span>Parameterization of Finite-Element Cryo-Hydrologic Sand Dune Model to Constrain Debris-Flow-Initiating Subsurface Temperatures and <span class="hlt">Pore-Water</span> Pressures, Great Kobuk Sand Dunes, Alaska</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dinwiddie, C. L.; Hooper, D. M.</p> <p>2015-05-01</p> <p>To explain how debris flows form at subfreezing air temperatures, we present meteorology-driven, numerical simulation-derived subsurface temperature and <span class="hlt">pore-water</span> pressure profiles in the Great Kobuk Sand Dunes of Alaska, for incipient flow events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ERL.....9j9002G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ERL.....9j9002G"><span>Reply to Comment on ‘<span class="hlt">Water</span> footprint of <span class="hlt">marine</span> protein consumption—aquaculture’s link to freshwater’</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gephart, Jessica A.; Pace, Michael L.; D'Odorico, Paolo</p> <p>2014-10-01</p> <p>In this reply to ‘<span class="hlt">water</span> footprint of <span class="hlt">marine</span> protein consumption—aquaculture’s link to freshwater,’ we argue that Troell et al’s calculation of the <span class="hlt">water</span> footprint of <span class="hlt">marine</span> aquaculture supports our assumption that <span class="hlt">marine</span> aquaculture requires a negligible amount of freshwater relative to the cost of terrestrial crop substitution that is the focus of our analysis in ‘freshwater savings from <span class="hlt">marine</span> protein consumption’. We recognize that the <span class="hlt">water</span> requirements of <span class="hlt">marine</span> aquaculture could be important for specific countries and will likely become more important at the global level as aquaculture incorporates more terrestrially-based feeds and as aquaculture comprises a larger percentage of total <span class="hlt">marine</span> fish production. In response to Troell et al’s comments on stagnant capture fisheries, we clarify that our original discussion encompassed several possible future conditions for these fisheries.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26152856','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26152856"><span>Climate change impacts on <span class="hlt">marine</span> <span class="hlt">water</span> quality: The case study of the Northern Adriatic sea.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rizzi, J; Torresan, S; Critto, A; Zabeo, A; Brigolin, D; Carniel, S; Pastres, R; Marcomini, A</p> <p>2016-01-30</p> <p>Climate change is posing additional pressures on coastal ecosystems due to variations in <span class="hlt">water</span> biogeochemical and physico-chemical parameters (e.g., pH, salinity) leading to aquatic ecosystem degradation. With the main aim of analyzing the potential impacts of climate change on <span class="hlt">marine</span> <span class="hlt">water</span> quality, a Regional Risk Assessment methodology was developed and applied to coastal <span class="hlt">marine</span> <span class="hlt">waters</span> of the North Adriatic. It integrates the outputs of regional biogeochemical and physico-chemical models considering future climate change scenarios (i.e., years 2070 and 2100) with site-specific environmental and socio-economic indicators. Results showed that salinity and temperature will be the main drivers of changes, together with macronutrients, especially in the area of the Po' river delta. The final outputs are exposure, susceptibility and risk maps supporting the communication of the potential consequences of climate change on <span class="hlt">water</span> quality to decision makers and stakeholders and provide a basis for the definition of adaptation and management strategies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900032299&hterms=hogg&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dhogg','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900032299&hterms=hogg&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dhogg"><span>Observed reflectivities and liquid <span class="hlt">water</span> content for <span class="hlt">marine</span> stratocumulus</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Coakley, J. A., Jr.; Snider, J. B.</p> <p>1989-01-01</p> <p>Simultaneous observations of cloud liquid <span class="hlt">water</span> content and cloud reflectivity are used to verify their parametric relationship in a manner consistent with simple parameterizations often used in general-circulation climate models. The column amount of cloud liquid <span class="hlt">water</span> was measured with a microwave radiometer on San Nicolas Island as described by Hogg et al., (1983). Cloud reflectivity was obtained through spatial coherence analysis of AVHRR imagery data as per Coakley and Baldwin (1984) and Coakley and Beckner (1988). The dependence of the observed reflectivity on the observed liquid <span class="hlt">water</span> is discussed, and this empirical relationship is compared with the parameterization proposed by Stephens (1978).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMGP24B..01C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMGP24B..01C"><span><span class="hlt">Water</span> and Electricity Do Mix: Studying Plates, Petroleum, and Permafrost using <span class="hlt">Marine</span> Electromagnetism</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Constable, S.</p> <p>2015-12-01</p> <p><span class="hlt">Marine</span> magnetotelluric (MT) and controlled-source electromagnetic (CSEM) sounding methods were developed in the early 1980's as deep-<span class="hlt">water</span> academic tools to study the oceanic lithosphere and mantle. Electrical conductivity is a strong function of porosity, temperature, melting, and volatile content, and so <span class="hlt">marine</span> MT and CSEM data can be used to address a variety of geological questions related to plate tectonics. These include the distribution of melt at mid-ocean ridges, the fate of fluids in subduction zones, and the nature of the lithosphere-asthenosphere boundary. With the advent of deepwater oil and gas drilling in the late 1990's, <span class="hlt">marine</span> EM methods were embraced by the exploration community, and are now routinely used to assist in exploration and make drilling decisions for wells costing $100M or more. For countries without conventional hydrocarbon resources, gas hydrate offers the potential for energy production, and <span class="hlt">marine</span> CSEM methods may be the only effective way to explore for and characterize this resource. The use of EM methods to map geothermal, groundwater, and mineral resources also has application in the <span class="hlt">marine</span> environment. <span class="hlt">Water</span> and electricity has proved to be a very successful mix!</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.A44D..06L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.A44D..06L"><span>Production and Cycling of Methylated Mercury Species in Arctic <span class="hlt">Marine</span> <span class="hlt">Waters</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lehnherr, I.; St. Louis, V. L.; Hintelmann, H.</p> <p>2009-12-01</p> <p>Monomethyl mercury (MMHg), a vertebrate neurotoxin which bioaccumulates through foodwebs, is found in some Arctic <span class="hlt">marine</span> mammals at levels that may be harmful to northern peoples consuming them as food. Unfortunately, sources of MMHg to polar <span class="hlt">marine</span> food webs remain unknown, in part due to the complex nature of Hg cycling in polar <span class="hlt">marine</span> <span class="hlt">waters</span>. Since 2005, we have been sampling the <span class="hlt">marine</span> <span class="hlt">waters</span> of the Canadian Arctic Archipelago from the Canadian Coast Guard research icebreaker CCGS Amundsen. Early results demonstrated that elevated concentrations of both MMHg and dimethyl mercury (DMHg, a toxic, gaseous Hg species) are found in sub-surface Arctic <span class="hlt">marine</span> <span class="hlt">waters</span> (89±36 pg L-1 and 73±37 pg L-1, respectively) despite low total Hg (THg) concentrations (290±220 pg L-1), suggesting an internal source of methylated Hg. We tested the hypothesis that methylated Hg species are produced directly in the <span class="hlt">marine</span> <span class="hlt">water</span> column using stable-isotope Hg tracers. Seawater samples were amended with 198Hg(II) and incubated for 0, 8, 16 or 24 hours to measure the production of MM198Hg, DM198Hg and gaseous elemental 198Hg(0) (GEM) over time. A second tracer, MM199Hg, was also added to quantify MMHg methylation (formation of DM199Hg), demethylation (loss of MM199Hg) and reduction (formation of 199Hg(0)). Preliminary analysis of the data indicates that Hg(II) is methylated in polar <span class="hlt">marine</span> <span class="hlt">waters</span> to form both MMHg (first order rate-constant km1 ~6x10-4 d-1) and DMHg (km2 ~5x10-6 d-1). We also found that DMHg production from MMHg is ~50x faster than with Hg(II) as the substrate. Furthermore, at a small number of sites, we measured methylation rates that were elevated by almost a full order of magnitude compared to the average, suggesting that methylation hotspots may exist in Arctic <span class="hlt">marine</span> <span class="hlt">waters</span>. However, during the less productive fall season when the CCGS Amundsen cruises were conducted, demethylation of MMHg generally appears to dominate in the <span class="hlt">water</span> column and can occur via a number</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015HESSD..12.6241H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015HESSD..12.6241H"><span>Determining the stable isotope composition of <span class="hlt">pore</span> <span class="hlt">water</span> from saturated and unsaturated zone core: improvements to the direct vapor equilibration laser spectroscopy method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hendry, M. J.; Schmeling, E.; Wassenaar, L. I.; Barbour, S. L.; Pratt, D.</p> <p>2015-06-01</p> <p>A method to measure the δ2H and δ18O composition of <span class="hlt">pore</span> <span class="hlt">waters</span> in saturated and unsaturated geologic core samples using direct vapor equilibration and laser spectroscopy (DVE-LS) was first described in 2008, and has since been widely adopted by others. Here, we describe a number of important methodological improvements and limitations encountered in routine application of DVE-LS over several years. Generally, good comparative agreement and accuracy is obtained between core <span class="hlt">pore</span> <span class="hlt">water</span> isotopic data obtained using DVE-LS and that measured on <span class="hlt">water</span> squeezed from the same core. In complex hydrogeologic settings, high-resolution DVE-LS depth profiles provide greater spatial resolution of isotopic profiles compared to long-screened or nested piezometers. When fluid is used during drilling and coring (e.g., <span class="hlt">water</span> rotary or wet sonic drill methods), spiking the drill fluid with 2H can be conducted to identify core contamination. DVE-LS analyses yield accurate formational isotopic data for fine-textured core (e.g., clay, shale) samples, but are less effective for cores obtained from saturated permeable (e.g., sand, gravels) geologic media or on chip samples that are easily contaminated by wet rotary drilling fluid. Data obtained from DVE-LS analyses of core samples collected using wet (contamination by drill <span class="hlt">water</span>) and dry sonic (<span class="hlt">water</span> loss by heating) methods were also problematic. Accurate DVE-LS results can be obtained on core samples with gravimetric <span class="hlt">water</span> contents < 5 % by increasing the sample size tested. Inexpensive Ziploc™ gas sampling bags were determined to be as good as, if not better, than other, more expensive bags. Sample storage in gas tight sample bags provides acceptable results for up to 10 days of storage; however, measureable <span class="hlt">water</span> loss and evaporitic isotopic enrichment occurs for samples stored for up to 6 months. With appropriate care taken during sample collection and storage, the DVE-LS approach for obtaining high resolution <span class="hlt">pore</span> <span class="hlt">water</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015HESS...19.4427H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015HESS...19.4427H"><span>Determining the stable isotope composition of <span class="hlt">pore</span> <span class="hlt">water</span> from saturated and unsaturated zone core: improvements to the direct vapour equilibration laser spectrometry method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hendry, M. J.; Schmeling, E.; Wassenaar, L. I.; Barbour, S. L.; Pratt, D.</p> <p>2015-11-01</p> <p>A method to measure the δ2H and δ18O composition of <span class="hlt">pore</span> <span class="hlt">waters</span> in saturated and unsaturated geologic core samples using direct vapour equilibration and laser spectrometry (DVE-LS) was first described in 2008, and has since been rapidly adopted. Here, we describe a number of important methodological improvements and limitations encountered in routine application of DVE-LS over several years. Generally, good comparative agreement, as well as accuracy, is obtained between core <span class="hlt">pore</span> <span class="hlt">water</span> isotopic data obtained using DVE-LS and that measured on <span class="hlt">water</span> squeezed from the same core. In complex hydrogeologic settings, high-resolution DVE-LS depth profiles provide greater spatial resolution of isotopic profiles compared to long-screened or nested piezometers. When fluid is used during drilling and coring (e.g. <span class="hlt">water</span> rotary or wet sonic drill methods), spiking the drill fluid with 2H can be conducted to identify core contamination. DVE-LS analyses yield accurate formational isotopic data for fine-textured core (e.g. clay, shale) samples, but are less effective for cores obtained from saturated permeable (e.g. sand, gravels) geologic media or on chip samples that are easily contaminated by wet rotary drilling fluid. Data obtained from DVE-LS analyses of core samples collected using wet (contamination by drill <span class="hlt">water</span>) and dry sonic (<span class="hlt">water</span> loss by heating) methods were also problematic. Accurate DVE-LS results can be obtained on core samples with gravimetric <span class="hlt">water</span> contents > 5 % by increasing the sample size tested. Inexpensive Ziploc™ gas-sampling bags were determined to be as good as, if not better than, other, more expensive specialty bags. Sample storage in sample bags provides acceptable results for up to 10 days of storage; however, measurable <span class="hlt">water</span> loss, as well as evaporitic isotopic enrichment, occurs for samples stored for up to 6 months. With appropriate care taken during sample collection and storage, the DVE-LS approach for obtaining high-resolution <span class="hlt">pore</span> <span class="hlt">water</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007GeCoA..71.4221W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007GeCoA..71.4221W"><span>Oxygen isotope biogeochemistry of <span class="hlt">pore</span> <span class="hlt">water</span> sulfate in the deep biosphere: Dominance of isotope exchange reactions with ambient <span class="hlt">water</span> during microbial sulfate reduction (ODP Site 1130)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wortmann, Ulrich G.; Chernyavsky, Boris; Bernasconi, Stefano M.; Brunner, Benjamin; Böttcher, Michael E.; Swart, Peter K.</p> <p>2007-09-01</p> <p>Microbially mediated sulfate reduction affects the isotopic composition of dissolved and solid sulfur species in <span class="hlt">marine</span> sediments. Experiments and field data show that the δ18O composition is also modified in the presence of sulfate-reducing microorganisms. This has been attributed either to a kinetic isotope effect during the reduction of sulfate to sulfite, cell-internal exchange reactions between enzymatically-activated sulfate (APS), and/or sulfite with cytoplasmic <span class="hlt">water</span>. The isotopic fingerprint of these processes may be further modified by the cell-external reoxidation of sulfide to elemental sulfur, and the subsequent disproportionation to sulfide and sulfate or by the oxidation of sulfite to sulfate. Here we report δ18O values from interstitial <span class="hlt">water</span> samples of ODP Leg 182 (Site 1130) and provide the mathematical framework to describe the oxygen isotope fractionation of sulfate during microbial sulfate reduction. We show that a purely kinetic model is unable to explain our δ18O data, and that the data are well explained by a model using oxygen isotope exchange reactions. We propose that the oxygen isotope exchange occurs between APS and cytoplasmic <span class="hlt">water</span>, and/or between sulfite and adenosine monophosphate (AMP) during APS formation. Model calculations show that cell external reoxidation of reduced sulfur species would require up to 3000 mol/m 3 of an oxidant at ODP Site 1130, which is incompatible with the sediment geochemical data. In addition, we show that the volumetric fluxes required to explain the observed δ18O data are on average 14 times higher than the volumetric sulfate reduction rates (SRR) obtained from inverse modeling of the porewater data. The ratio between the gross sulfate flux into the microbes and the net sulfate flux through the microbes is depth invariant, and independent of sulfide concentrations. This suggests that both fluxes are controlled by cell density and that cell-specific sulfate reduction rates remain constant with depth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930038725&hterms=marine+biology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dmarine%2Bbiology','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930038725&hterms=marine+biology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dmarine%2Bbiology"><span>A photoautotrophic source for lycopane in <span class="hlt">marine</span> <span class="hlt">water</span> columns</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wakeham, Stuart G.; Freeman, Katherine H.; Pease, Tamara K.; Hayes, J. M.</p> <p>1993-01-01</p> <p>Suspended particulate matter and recent sediments from diverse oceanic sites have been investigated for their contents of lycopane. Lycopane was present in all samples, including both oxic and anoxic <span class="hlt">water</span> column and sediments. The highest concentrations in the <span class="hlt">water</span> column were found in surface <span class="hlt">waters</span> of the central Pacific gyre (1.5 ng/L) and in the anoxic <span class="hlt">waters</span> of the Cariaco Trench (1.1 ng/L) and the Black Sea (0.3 ng/L). Vertical concentration profiles suggest that lycopane is probably algal in origin. Moreover, biogeochemical conditions in anoxic zones apparently result in a secondary production of lycopane from an as yet unidentified precursor. Compound-specific carbon isotopic analyses have been carried out on lycopane from <span class="hlt">water</span> column and sediment samples. Isotopic compositions of lycopane range between -23.6 and -32.9 percent and are consistent with a photoautotrophic origin. We postulate that some lycopane is produced in surface <span class="hlt">waters</span> of the ocean, while additional lycopane is produced in anoxic zones by anaerobic microbial action on an algal precursor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70028867','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70028867"><span>Offshore <span class="hlt">marine</span> observation of Willow Ptarmigan, including <span class="hlt">water</span> landings, Kuskokwim Bay, Alaska</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Zimmerman, Christian E.; Hillgruber, Nicola; Burril, Sean E.; St. Peters, Michelle A.; Wetzel, Jennifer D.</p> <p>2005-01-01</p> <p>We report an observation of Willow Ptarmigan (Lagopus lagopus) encountered 8 to 17 km from the nearest shoreline on Kuskokwim Bay, Alaska, on 30 August 2003. The ptarmigan were observed flying, landing on our research vessel, and landing and taking off from the <span class="hlt">water</span> surface. We also report on one other observation of ptarmigan sitting on the <span class="hlt">water</span> surface and other <span class="hlt">marine</span> observations of ptarmigan from the North Pacific Pelagic Seabird Database. These observations provide evidence that Willow Ptarmigan are capable of dispersing across large bodies of <span class="hlt">water</span> and landing and taking off from the <span class="hlt">water</span> surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.B23C0615K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.B23C0615K"><span>Microbial Controlled Carbon Monoxide Budget in the <span class="hlt">Marine</span> Surface <span class="hlt">Waters</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kwon, Y. S.; Rhee, T. S.</p> <p>2015-12-01</p> <p>In the upper ocean, the dissolved CO exhibits typical diurnal cycle being produced by photolytic decomposition of chromophoric dissolved organic matter (CDOM), consumed by microbes, and outgassed by the gas exchange processes. To investigate the CO budget in the mixed layer, we measured air-sea gas exchange, microbial consumption rate, and CDOM on-board at two stark different <span class="hlt">marine</span> environments in summer season of 2012: the Amundsen Sea, Antractica, and the North Pacific. Dark incubation experiments revealed that microbial consumption rate in the North Pacific was 4.5 nM d-1 whilst 0.8 nM d-1 in the Amundsen Sea. Also CO production rate was about 3.5-times higher in the North Pacific (2.4 nM d-1) likely due to weak dilution and strong photochemical production. This different CO budget between the two regions renders different amplitude of diurnal variation of dissolved CO. That is, compared to the Amundsen Sea, CO was produced faster at daytime and removed faster at nighttime in the North Pacific where the amplitude of CO cycle is larger. In both regions, sea-to-air flux was insignificant (about 0.1 nM d-1 for the both regions) and microbial consumption overwhelmed CO sinks. A simple mass-balance model simulated well our observations, suggesting that other processes than mentioned above were unrevealed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/292932','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/292932"><span>Application of toxicity-based fractionation techniques and structure-activity relationship models for the identification of phototoxic polycyclic aromatic hydrocarbons in sediment <span class="hlt">pore</span> <span class="hlt">water</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kosian, P.A.; Makynen, E.A.; Monson, P.D.; Mount, D.R.; Ankley, G.T.; Spacie, A.; Mekenyan, O.G.</p> <p>1998-06-01</p> <p>Recent studies conducted at their laboratory have shown that sediments contaminated with complex mixtures of polycyclic aromatic hydrocarbons (PAHs) can exhibit enhanced toxicity (lethality) to a variety of aquatic species when the samples are tested under ultraviolet (UV) light designed to mimic the wavelengths present in sunlight. However, because these contaminated sediments can contain literally thousands of chemicals, it is difficult to use conventional analytical techniques to identify those compounds responsible for photo-induced toxicity. The purpose of this study was to adapt existing toxicity identification evaluation methods to attempt to identify those compounds contributing to the phototoxicity observed in their sediment samples. <span class="hlt">Pore</span> <span class="hlt">water</span> obtained from sediments collected near an oil refinery discharge was toxic to Lumbriculus variegatus following exposure to UV light, while organisms exposed to the same <span class="hlt">pore</span> <span class="hlt">water</span>, but without subsequent UV treatment, showed no toxic effect. Solid-phase extraction disks and high-performance liquid chromatography were used, in conjunction with toxicity tests with L. variegatus, to extract and fractionate phototoxic chemicals from the <span class="hlt">pore</span> <span class="hlt">water</span>. Phototoxic fractions analyzed by gas chromatography-mass spectrometry revealed the presence of a number of aliphatic hydrocarbons, substituted PAHs, and PAHs containing heteroatoms. Chemicals were screened for their phototoxic potential based on empirical data and predictive models. A refined list of PAHs was then evaluated on the basis of their phototoxic potency as defined by a recently developed quantitative structure-activity relationship model and estimates of their bioaccumulation potential. Based on the model predictions of potency and bioaccumulation, nine likely phototoxic chemicals were identified.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeCoA.197..193G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeCoA.197..193G"><span>Effects of a thermal perturbation on mineralogy and <span class="hlt">pore</span> <span class="hlt">water</span> composition in a clay-rock: An experimental and modeling study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gailhanou, H.; Lerouge, C.; Debure, M.; Gaboreau, S.; Gaucher, E. C.; Grangeon, S.; Grenèche, J.-M.; Kars, M.; Madé, B.; Marty, N. C. M.; Warmont, F.; Tournassat, C.</p> <p>2017-01-01</p> <p>The physical and chemical properties of clay-rocks are, at least partly, controlled by the chemical composition of their <span class="hlt">pore</span> <span class="hlt">water</span>. In evaluating the concept of disposing of radioactive waste in clay-rock formations, determining <span class="hlt">pore</span> <span class="hlt">water</span> composition is an important step in predicting how a clay-rock will behave over time and as a function of external forces, such as chemical and thermal perturbations. This study aimed to assess experimental and modeling methodology to calculate <span class="hlt">pore</span> <span class="hlt">water</span> composition in a clay-rock as a function of temperature (up to 80 °C). Hydrothermal alteration experiments were carried out on clay-rock samples. We conducted comprehensive chemical and mineralogical characterization of the material before and after reaction, and monitored how the chemical parameters in the liquid and gas phases changed. We compared the experimental results with the a priori predictions made by various models that differed in their hypotheses on the reactivity of the minerals present in the system. Thermodynamic equilibrium could not be assessed unequivocally in these experiments and most of the predicted mineralogy changes were too subtle to be tracked quantitatively. However, from observing the neo-formation of minerals such as goethite we were able to assess the prominent role of Fe-bearing phases in the outcome of the experiments, especially for the measured pH and pCO2 values. After calibrating the amount of reacting Fe-bearing phases with our data, we proposed a thermodynamic model that was capable of predicting the chemical evolution of the systems under investigation as well as the evolution of other systems already published in the literature, with the same clay-rock material but with significant differences in experimental conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5489554','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5489554"><span>Cultivation of macroscopic <span class="hlt">marine</span> algae and fresh <span class="hlt">water</span> aquatic weeds</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ryther, J.H.</p> <p>1982-02-01</p> <p>The ORCA clone of the red seaweed Gracilaria tikvahiae has been in culture continuously for over two years. Yield for the past year has averaged 12 g ash-free dry wt/m/sup 2/ .day (17.5 t/a.y) in suspended 2600-1 aluminum tank cultures with four exchanges of enriched seawater per day and continuous aeration. Yields from nonintensive pond-bottom culture, similar to commercial Gracilaria culture methods in Taiwan, averaged 3 g afdw/m/sup 2/.day in preliminary experiments. Rope and spray cultures were not successful. Yields of <span class="hlt">water</span> hyacinths from March 1978 to March 1979 averaged 25 g afdw/m/sup 2/.day (37 t/a.y). Season, nutrient availability (form and quantity) and stand density were found to affect the relative proportions of structural and nonstructural tissue in <span class="hlt">water</span> hyacinths and thereby significantly affect digestibility of and methane production by the plants. Pennywort (Hydrocotyle) grew poorly in winter and its annual yield averaged only one-third that of <span class="hlt">water</span> hyacinth. <span class="hlt">Water</span> lettuce (Pistia) appears more comparable to hyacinths in preliminary studies and its yields will be monitored throughout a complete year. Stable, continuous anaerobic digestion of both <span class="hlt">water</span> hyacinths and Gracilaria has been maintained with an average gas production from both species of 0.4 1/g volatile solids at 60% methane.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFMPP51D..02T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFMPP51D..02T"><span><span class="hlt">Marine</span> Archaea lipids: patterns and provenance in the <span class="hlt">water</span>-column</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Turich, C.; Freeman, K. H.; Bruns, M.; Conte, M.; Jones, A.; Wakeham, S. G.</p> <p>2007-12-01</p> <p>The paleotemperature proxy TEX86 (TetraEther indeX) is based on a robust correlation between the ratio of <span class="hlt">marine</span> archaeal lipids (glycerol dialkyl glycerol tetraethers (GDGTs) with different numbers of rings), and temperature. The potential paleoceanographic utility of this proxy is tremendous, and it has already been used successfully in a number of paleoenvironments (e.g. Younger Dryas detection in the southern hemisphere) but poses problems in others (e.g. the southern North Sea with high sediment input). The physiological, phylogenetic, and physical controls on this correlation remain speculative and difficult to test. Different archaeal subgroups live throughout the <span class="hlt">water</span> column (some with unknown metabolisms), only one representative of <span class="hlt">marine</span> Crenarchaeota and no <span class="hlt">marine</span> Euryarchaeota are available in pure culture for experimentation, and lipid ratios observed in enrichment versus in situ samples inexplicably differ. We hypothesize that lipid distribution patterns are affected by ecological changes. We measured archaeal lipids from globally distributed samples of freshwater, <span class="hlt">marine</span>, and hypersaline suspended particulate matter. Cluster analysis of relative lipid distributions identified four distinct groups, including: 1) <span class="hlt">marine</span> epipelagic <span class="hlt">waters</span>, 2) <span class="hlt">marine</span> mesopelagic/upwelling <span class="hlt">waters</span>, 3) freshwater/estuarine <span class="hlt">waters</span>, and 4) hypersaline <span class="hlt">waters</span>. We propose that community changes regulate the lipid patterns distinguishing these groups, including epipelagic and mesopelagic/upwelling zones. Lipid patterns in mesopelagic/upwelling <span class="hlt">waters</span> are similar to those expected for nitrifying Group I Crenarchaeota-- predominance of crenarchaeol and abundant cyclic GDGTs. Non-metric multidimensional analysis shows this pattern is associated with high nitrate concentrations. Furthermore, the difference between calculated TEX86 temperature and in situ temperature from surface to deep <span class="hlt">waters</span> correlates with nitrate concentrations, enforcing a connection between community change</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910001211','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910001211"><span>Dependence of <span class="hlt">marine</span> stratocumulus reflectivities on liquid <span class="hlt">water</span> paths</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Coakley, James A., Jr.; Snider, Jack B.</p> <p>1990-01-01</p> <p>Simple parameterizations that relate cloud liquid <span class="hlt">water</span> content to cloud reflectivity are often used in general circulation climate models to calculate the effect of clouds in the earth's energy budget. Such parameterizations have been developed by Stephens (1978) and by Slingo and Schrecker (1982) and others. Here researchers seek to verify the parametric relationship through the use of simultaneous observations of cloud liquid <span class="hlt">water</span> content and cloud reflectivity. The column amount of cloud liquid was measured using a microwave radiometer on San Nicolas Island following techniques described by Hogg et al., (1983). Cloud reflectivity was obtained through spatial coherence analysis of Advanced Very High Resolution Radiometer (AVHRR) imagery data (Coakley and Beckner, 1988). They present the dependence of the observed reflectivity on the observed liquid <span class="hlt">water</span> path. They also compare this empirical relationship with that proposed by Stephens (1978). Researchers found that by taking clouds to be isotropic reflectors, the observed reflectivities and observed column amounts of cloud liquid <span class="hlt">water</span> are related in a manner that is consistent with simple parameterizations often used in general circulation climate models to determine the effect of clouds on the earth's radiation budget. Attempts to use the results of radiative transfer calculations to correct for the anisotropy of the AVHRR derived reflectivities resulted in a greater scatter of the points about the relationship expected between liquid <span class="hlt">water</span> path and reflectivity. The anisotropy of the observed reflectivities proved to be small, much smaller than indicated by theory. To critically assess parameterizations, more simultaneous observations of cloud liquid <span class="hlt">water</span> and cloud reflectivities and better calibration of the AVHRR sensors are needed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18404233','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18404233"><span>Is the mobility of the <span class="hlt">pore</span> walls and <span class="hlt">water</span> molecules in the selectivity filter of KcsA channel functionally important?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kraszewski, Sebastian; Yesylevskyy, Semen O; Boiteux, Céline; Ramseyer, Christophe; Kharkyanen, Valery N</p> <p>2008-04-28</p> <p>We performed in-depth analysis of the forces which act on the K(+) ions in the selectivity filter of the KcsA channel in order to estimate the relative importance of static and dynamic influence of the filter wall and <span class="hlt">water</span> molecules on ion permeation and selectivity. The forces were computed using the trajectories of all-atom molecular dynamics simulations. It is shown that the dynamics of the selectivity filter contributes about 3% to the net force acting on the ions and can be neglected in the studie